In ovo administration of the Marek's disease vaccine in conjunction with 25-hydroxyvitamin D3 and its subsequent effects on the performance and immunity-related characteristics of Ross 708 broiler hatchlings1,2,3

The combined effects of the in ovo injection of commercial Marek's disease vaccine (MDV) and various levels of 25-hydroxyvitamin D3 (25OHD3) on the hatch variables, immunological measurements, and gene expression of Ross 708 hatchling broilers were investigated. A total of 5 in ovo injection treatments that were applied at 18 d of incubation (doi) included: 1) noninjected (control); or a 50 μL solution volume of 2) MDV alone; or MDV combined with 3) 0.6 μg of 25OHD3; 4) 1.2 μg of 25OHD3; or 5) 2.4 μg of 25OHD3. At hatch, hatchability of set and live embryonated eggs, hatchling body weight, hatch residue analysis, serum IgY and alpha-1 acid glycoprotein (AGP) concentrations, and the expression of genes related to immunity (INFα, INFβ, INFγ, TLR-3, and TLR-21) and vitamin D3 activity (1 α-hydroxylase, 24 hydroxylase, and vitamin D receptor) were determined. No significant treatment differences were observed for hatchability of set and live embryonated eggs, or for serum IgY and AGP concentrations. However, hatchling body weight was higher when MDV was combined with either 1.2 or 2.4 μg of 25OHD3 than when MDV was provided alone or in combination with 0.6 μg of 25OHD3. Also, in comparison to the noninjected treatment group, the expression of the genes for 1 α-hydroxylase and 24 hydroxylase was improved when MDV was combined with either 1.2 or 2.4 μg of 25OHD3. Lastly, expression of the genes linked to viral detection (TLR-3) and antibody production (INF-β) was increased in those treatments that contained any level of 25OHD3. These results indicate that in comparison to controls, the effects of MDV were observed to be greater on hatchling BW and splenic gene expression when it was administered in combination with the 1.2 or 2.4 μg doses of 25OHD3. Further research is needed to determine the posthatch effects of the administration of various levels of 25OHD3 in combination with MDV.

Effects of the in ovo injection of an Escherichia coli vaccine on the hatchability and quality characteristics of commercial layer hatchlings

In the commercial egg industry, avian pathogenic Escherichia coli (APEC) can lead to significant economic loss. The Poulvac E. coli vaccine (PECV) is a commercially available attenuated live vaccine commonly applied via spray or drinking water to protect against losses associated with colibacillosis. The PECV has not been tested in layer hatching eggs using in ovo injection. Therefore, the purpose of this experiment was to determine the effects of injecting 50 μL of different doses of the PECV into Hy-Line W-36-layer hatching eggs on the hatchability and quality characteristics of hatchlings. At 18 d of incubation (DOI), treatments included 1 noninjected and 1 diluent-injected control. Furthermore, PECV treatments included a full dose (4.4 × 108E. coli CFU) or serial dilutions of the full dose to produce 4.4 × 106, 4.4 × 104, or 4.4 × 102 CFU doses of E. coli. In ovo injections targeted the amnion. Percent hatchability of live embryonated eggs (HI), percent residue eggs, hatchling mortality, and female chick whole and yolk-free BW, relative yolk sac weight, and body length were among the variables examined. Treatment significantly (P < 0.0001) affected HI, with HI being highest in the control groups (97.3% in the noninjected and 94.2% in the diluent-injected), and with HI values being 89.0, 88.9, 84.4, and 71.2% in the 4.4 × 102, 4.4 × 104, 4.4 × 106, and 4.4 × 108 CFU E. coli dose treatments, respectively. The percentage of live embryos that did not complete hatch but that pipped internally (P = 0.024) or externally (P < 0.0001) were significantly affected by treatment, with percentages being highest in the 4.4 × 108 CFU treatment. Female chick body length was significantly (P < 0.0001) affected by treatment and was longer in both control groups and in the 1 × 102 CFU E. coli treatment in comparison to all other treatments. Yolk-free female chick BW was significantly (P = 0.034) affected by treatment and was lower in the 4.4 × 106 CFU and 4.4 × 108 CFU treatments when compared to the diluent-injected control group. An increase in the E. coli concentration administered in the amnion of embryonated layer hatching eggs at 18 DOI decreased hatch success and female chick yolk-free BW and body length.

Onset of the humoral immune response of layer chicks vaccinated in ovo with strain F Mycoplasma gallisepticum vaccine and evidence of male-biased mortality,,

Previous trials in which layers were in ovo-vaccinated against strain F Mycoplasma gallisepticum (FMG) showed that nearly 50% of the birds produced IgM antibody against FMG at 6 wk of age (WOA). Standard FMG vaccination application at 9 or 10 woa, result in this percentage at approximately 15 woa. This study investigated when FMG in ovo-vaccinated birds initiate a humoral immune response prior to 6 wk, and if sex influences this response. Hy-Line W-36 embryonated eggs were either not vaccinated (controls) or in-ovo vaccinated with a 50 µL volume of a 10⁻⁶ dilution of Poulvac MycoF vaccine (Zoetis). For each treatment group, 384 straight-run chicks were reared. At hatch and at 2, 3, 5, 7, 14, 21, and 28 d post-hatch, 54 birds per treatment were individually weighed and a blood sample was collected for Mycoplasma gallisepticum (MG) IgM antibody detection. ELISA was run on blood samples at 14, 21, and 28 d to distinguish IgG antibody production. At each age, BW was not different between vaccinated and control chicks (all P > 0.19). Males, however, outweighed females starting at d 5 (P = 0.02). Mortality was 1.0% for the control birds and 12.2% for the FMG birds during the first 2 wk. The majority (72.3%) of the mortalities in the FMG group were male. The percentage of control and FMG in ovo-vaccinated birds with IgM antibody production was 0% and 1.9% on d 7, 0% and 31.5% on d 14, 1.9% and 55.9% on d 21, and 0% and 60.6% on d 28, respectively. IgG antibody production in the FMG in ovo-vaccinated birds was 0.0% at 14 d, 2.9% at 21 d, and 21.2% at 28 d of age. All control birds tested negative for FMG-IgG production. In conclusion, the earliest detection of MG antibodies after in ovo vaccination with live FMG occurred at 7 d. Male layer chickens were more susceptible to the effects of an in ovo FMG vaccine than females.

Effects of the in ovo injection of vitamin D3 and 25-hydroxyvitamin D3 in Ross 708 broilers subsequently challenged with coccidiosis. I. performance, meat yield and intestinal lesion incidence1,2,3

Effects of the in ovo administration of vitamin D₃ (D₃) and 25-hydroxyvitamin D₃ (25OHD₃) on broiler intestinal lesion incidence, performance and breast meat yield after a coccidiosis challenge were investigated. On each of 10 incubator tray levels, 10 Ross 708 broiler hatching eggs were randomly assigned to each of the following 5 in ovo injection treatments administrated at 18 d of incubation (doi): 1) noninjected; 2) diluent; diluent containing either 3) 2.4 μg D₃ (D₃), 4) 2.4 μg 25OHD₃ (25OHD₃), or 5) 2.4 μg D₃ + 2.4 μg 25OHD₃ (D₃+25OHD₃). A 50 μL solution volume was injected into each egg using an Inovoject multi-egg injector. Four male chicks were randomly assigned to each of 80 battery cages in each of 2 rooms. Half of the treatment-replicate cages (8) in each room were challenged with a 20× live coccidial vaccine at 14 d of age (doa). One randomly selected bird from each of 4 treatment-replicate cages was scored for coccidiosis lesions before and 2 wk after challenge. Mean BW, BW gain (BWG), feed intake, and feed conversion ratio were determined for all birds from 0 to 14, 15 to 28, and 29 to 41 doa. Carcass weight, and the absolute and relative (% of carcass weight) weights of carcass parts were determined in 3 birds per treatment-replicate cage at 42 doa. Hatchability of live embryonated injected eggs and hatch residue were not affected by treatment. Across challenge treatment, birds in the 25OHD₃ treatment group experienced an increase in BWG between 29 and 41 doa when compared to the D₃ or diluent-injected birds. Furthermore, pectoralis major muscle percentage tended (P = 0.059) to increase in birds belonging to the 25OHD₃ treatment in comparison to birds in the D₃ or diluent-injected treatments. These results indicate that regardless of challenge treatment, 2.4 μg of 25OHD₃ may increase the BWG and breast meat yield of birds relative to those that only received an injection of commercial diluent.

Effects of the in ovo injection of vitamin D3 and 25-hydroxyvitamin D3 in Ross 708 broilers subsequently fed commercial or calcium and phosphorus-restricted diets. II. Immunity and small intestine morphology1,2,3

Effects of the in ovo injection of vitamin D₃ (D₃) and 25-hydroxyvitamin D₃ (25OHD₃) on the immunity and small intestine morphology of broilers fed calcium and phosphorus-restricted diets were investigated. At 18 d of incubation (doi), live embryonated Ross 708 broiler hatching eggs were in ovo-injected with a 50 μL solution of one of the following treatments using an Inovoject multiegg injector: 1) diluent (control); diluent containing either 2) 2.4 μg D₃; 3) 2.4 μg 25OHD₃; or 4) 2.4 μg D₃ + 2.4 μg 25OHD₃. At hatch, 18 randomly selected male broilers belonging to one of the 4 in ovo injection treatments were placed in each of 12 floor pens and were fed either a commercial diet or a diet restricted by 20% in calcium and available phosphorus (ReCaP) content for the starter, grower and finisher dietary phases. Concentrations of plasma IgG and IgM at 14 d of age (doa) and α-1-acid glycoprotein at 40 doa were determined. Bursa, liver, spleen, duodenum, jejunum, and ileum weights were recorded at 7, 14, and 40 doa and small intestine histology was evaluated at 14 and 40 doa. Blood and organ samples were randomly collected from 1 bird in each of the 6 replicate pens within each of the 8 (4 in ovo x 2 dietary) treatment groups. Plasma IgG levels were higher in 25OHD₃ than in diluent or D₃ in ovo-injected birds. At 14 doa, a higher jejunal villus length (VL) to crypt depth (CD) ratio (RVC) was observed in birds that were in ovo-injected with 25OHD₃ alone as compared to all other in ovo injection treatments. At 40 doa, ileal VL increased and jejunal CD decreased in commercial diet-fed birds compared to ReCaP diet-fed birds. In conclusion, the in ovo injection of 25OHD₃ alone increased the immune response and improved the small intestine morphology and subsequent nutrient uptake of Ross 708 broilers. However, a ReCaP diet was observed to be detrimental to their small intestine morphology.

Effects of the in ovo injection of vitamin D3 and 25-hydroxyvitamin D3 in Ross 708 broilers subsequently fed commercial or calcium and phosphorus-restricted diets. I. Performance, carcass characteristics, and incidence of woody breast myopathy1,2,3

Effects of the in ovo-injection of vitamin D₃ (D₃) and 25-hydroxyvitamin D₃ (25OHD₃) on broiler performance, carcass characteristics, and woody breast myopathy (WBM) incidence were investigated. Live embryonated Ross 708 broiler hatching eggs (2,880) were randomly assigned to one of the following in ovo injection treatments: (1) diluent (50 μL); diluent (50 μL) containing either (2) 2.4 μg D₃; (3) 2.4 μg 25OHD₃; or (4) 2.4 μg D₃ + 2.4 μg 25OHD₃. Eggs were injected at 18 d of incubation (doi) using an Inovoject multiegg injector. At hatch, 18 male chicks were randomly placed in each of 6 replicate pens belonging to each in ovo injection and, dietary treatment combination. Birds were fed either a commercial diet or a diet restricted in calcium and phosphorous (ReCaP) content by 20% for the starter, grower and finisher dietary phases. Broiler performance was determined in each dietary phase and breast muscle yield was also determined at 14 and 40 d of age (doa). At 41 and 46 doa, birds were processed for determination of WBM, carcass weight, and the absolute and relative (% of carcass weight) weights of various carcass parts. Compared to birds fed the commercial diet, birds fed ReCaP diets experienced a reduction in performance from 14 to 40 doa, in breast meat yield at 41 and 46 doa, and in WBM at 41 and 46 doa. At 14 and 40 doa, breast meat yield in birds that received an in ovo injection of 25OHD₃ alone was higher compared to birds that received diluent alone or a combination of D₃ and 25OHD₃. Lower WBM incidence in ReCaP-fed birds was associated with a lower breast weight. An increase in breast meat yield in response to 25OHD₃ alone may be due to improved immunity and small intestine morphology. However, further study is needed to determine the aforementioned effects.

Effects of administration of an in ovo coccidiosis vaccine at different embryonic ages on vaccine cycling and performance of broiler chickens,. Poult Sci 2020;100:100914. [PMID: 33518328 PMCID: PMC7936202 DOI: 10.1016/j.psj.2020.11.078]

Use of a live coccidiosis vaccine has become an increasingly common method to control coccidiosis, especially in antibiotic-free broiler production. The Inovocox EM1 vaccine (EM1) is recommended for the vaccination of embryonated broiler hatching eggs between 18.0 and 19.0 d of incubation (doi). This allows for earlier acquisition of immunity to wild-type coccidia. However, it is unclear whether the difference in embryo age at the time of in ovo injection can influence the effect of the vaccine during grow-out as well as if the growth performance of broiler chickens is affected. Therefore, the objective of the study was to evaluate the effects of 2 injection ages (18.5 and 19.0 doi) and 3 injection types (noninjected, diluent, and vaccine) in a 3 × 2 factorial design, consisting of 10 replicates per treatment (60 treatment-replicate groups). There was a significant effect of injection age on BW at 0, 14, and 35 d after hatch, with a difference in the BW of birds belonging to the 18.5 and 19.0 doi groups up to day 35 after hatch. There was a significant effect of injection type on BW gain, feed intake, and FCR between 0 and 28 d after hatch. Between 0 and 35 d, FCR was lower in the vaccine-injected group in comparison with the noninjected and diluent control groups. Furthermore, total intestine coccidia and lesion indices were higher in the vaccine-18.5 treatment group in comparison with the diluent-18.5 treatment group at 28 d. In conclusion, hatchling weight was affected by injection age, and this subsequently affected growth performance. Furthermore, intestinal coccidia cycling peaked at 28 d, resulting in a reduction in growth performance through 28 d and subsequent compensatory growth by 35 d. There was no significant difference in coccidiosis cycling between the vaccine-18.5 and vaccine-19.0 doi treatment combination groups.

Research Note: Effects of the in ovo injection of organic zinc, manganese, and copper and posthatch holding time before placement on broiler body temperature during grow out

Effects of the in ovo injection of organic microminerals (OM) (zinc, manganese, and copper) and posthatch holding time (HT) on the daily body temperature (bt) of broilers during grow out were determined. The hatching eggs from a Ross 708 breeder flock at 32 wk of age were incubated under standard commercial conditions. At 17 d of incubation, eggs were randomly allocated to 3 in ovo OM injection treatment (TRT) groups, and at 21 d of incubation, male hatchlings were randomly allocated to 2 posthatch HT treatment groups. Eggs were either not injected or were in ovo injected with diluent only or diluent containing the OM mixture. A 0-hour HT group had immediate access to water and feed, and a 24-hour HT (24HT) group contained birds that were kept in transport baskets in their pens without access to feed and water for 24 h before being released. Fifteen male birds were placed in each of 36 litter floor pens in a temperature-controlled facility. Approximately 2 birds in each of 6 replicate pens belonging to each TRT-HT combination had temperature transponders inserted subcutaneous in the mid-dorsal region of the neck. All birds were brooded under standard commercial conditions and had ad libitum access to feed and water after their respective HT. The bt of the same birds were determined daily at the same time each day beginning at hatch and ending on 39 d of posthatch age (AGE). There were no significant main or interactive effects involving TRT or HT for bt. However, there was a significant (P ≤ 0.0001) main effect because of AGE. A general increase in bt occurred during the 39 d grow out period. At hatch, bt was 40.54 ± 0.056°C and at AGE 39 was 41.46 ± 0.055°C. Under standard brooding conditions, a general increase in bt occurred in the Ross 708 broilers. However, these birds did not exhibit a significant bt response to TRT or a 24HT before placement.

Improvement in the performance and inflammatory reaction of Ross 708 broilers in response to the in ovo injection of 25-hydroxyvitamin D3

The effects of the in ovo administration of vitamin D₃ (D₃) and its metabolite, 25-hydroxyvitamin D₃ (25OHD₃)_, on the performance, breast meat yield, and inflammatory responses of broilers fed commercial diets were investigated. Live embryonated Ross 708 broiler hatching eggs were randomly assigned to one of the following 5 in ovo injection treatments at 18 d of incubation: 1) noninjected; 2) diluent; diluent containing 3) 2.4-μg D₃, 4) 2.4-μg 25OHD₃, or 5) 2.4-μg D₃ + 2.4-μg 25OHD₃. A 50-μL solution volume of each prespecified treatment was injected into each egg using an Inovoject multiegg injector. At hatch, 18 male chicks were randomly assigned to each of 30 floor pens. The BW, BW gain, feed intake, and feed conversion ratio of the birds were determined in each dietary phase. At 14, 28, and 39 d of posthatch age (doa), plasma α-1-acid glycoprotein (AGP) levels in 1 bird in each of 6 replicate pens per treatment were determined at 14 and 39 doa. The pectoralis major and minor weights of those same birds were also determined. The remaining birds were processed at 43 doa, and the weights of their processing parts were determined. At 39 doa, the in ovo injection of 25OHD₃ alone decreased plasma AGP concentrations in comparison with the noninjected, diluent, and D₃-alone treatment groups. In addition, birds that received 25OHD₃ alone had a greater BW at 42 doa than birds in the noninjected, diluent, and D₃-alone treatment groups. At 39 and 43 doa, breast meat yield was increased in response to the in ovo injection of 25OHD₃ alone in comparison to all other treatments. These results indicate that the in ovo injection of 2.4 μg of 25OHD₃ resulted in an improvement in the performance and inflammatory responses of broilers. A reduction in the inflammatory response subsequent to the in ovo injection of 2.4 μg of 25OHD₃ may have led to an increase in broiler performance.

Effects of source and level of in ovo-injected vitamin D3 on the hatchability and serum 25-hydroxycholecalciferol concentrations of Ross 708 broilers

Effects of the in ovo injection of vitamin D3 (D3) and 25-hydroxycholecalciferol (25OHD3) on broiler embryo serum 25OHD3 concentrations, hatchability, and hatchling somatic characteristics were determined. Eggs from a 35-wk-old commercial Ross 708 broiler breeder flock were set in a single-stage incubator with 11 treatments represented on each of 8 incubator tray levels (blocks). Each treatment group within a flat on each tray level contained 30 eggs. Control treatments were noninjected and diluent injected. Vitamin treatments were commercial diluent containing 0.6 μg D3, 0.6 μg 25OHD3, 0.6 μg D3 + 0.6 μg 25OHD3, 1.2 μg D3, 1.2 μg 25OHD3, 1.2 μg D3 + 1.2 μg 25OHD3, 2.4 μg D3, 2.4 μg 25OHD3, or 2.4 μg D3 + 2.4 μg 25OHD3. At 432 h of incubation (hoi), 50-μL solution volumes were injected. Blood samples were collected at 462 hoi for serum 25OHD3 analysis, and hatchability of injected live embryonated eggs (HI) was determined at 492 and 516 hoi. At 516 hoi, hatchling yolk-free BW and weights of the liver and yolk sac were determined. Percentage of yolk moisture and dry mater was calculated. At 492 and 516 hoi, HI did not differ between treatments. Embryos that received 1.2 μg or more of either vitamin D3 source alone or in combination had higher serum 25OHD3 concentrations than those that were injected with diluent alone or diluent containing 0.6 μg of D3. Hatchlings that received 1.2 or 2.4 μg of 25OHD3 had higher percentage of yolk dry matter or lower percentage of yolk moisture levels than noninjected controls and those that received D3 alone at any level. These results indicate that the in ovo injection of either vitamin D3 source at levels equal to or higher than 1.2 μg resulted in serum 25OHD3 concentrations that were higher than that of noninjected controls. In addition, the in ovo injection of 1.2 μg or higher of either vitamin D3 source did not negatively affect broiler HI or chick quality.

Effects of dietary Original XPC on selected blood variables in layer pullets challenged with Mycoplasma gallisepticum,. Poult Sci 2020;99:4373-4383. [PMID: 32867981 PMCID: PMC7598016 DOI: 10.1016/j.psj.2020.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Effects of dietary Original XPC (XPC) on 17 selected blood variables in commercial layer pullets challenged with the virulent, low-passage R strain of Mycoplasma gallisepticum (R_lowMG) were investigated. Hy-Line W-36 pullets sourced from M. gallisepticum–clean layer breeders were fed a basal diet with XPC (1.25 kg/metric ton) or without from hatch until 12 wk of age (woa). At 8 and 10 woa, half of the birds in each dietary treatment were challenged with R_lowMG. Blood samples were taken immediately before the initial R_lowMG challenge at 8 woa and again at 12 woa (4 wk after challenge). At 8 woa, blood pH was lower and glucose concentration was higher in the preassigned challenge treatment groups. At 12 woa, the concentration of oxygen dissolved in the blood was significantly lower in the R_lowMG-challenged group than the unchallenged group of birds regardless of dietary treatment. The R_lowMG challenge significantly increased blood carbon dioxide partial pressure, calcium, sodium, anion gap, osmolality, glucose, and corticosterone levels but significantly decreased blood oxygen partial pressure, oxyhemoglobin concentration, concentration of oxygen dissolved in the blood, chloride, and pH levels. Because blood pH and glucose concentration at 8 woa were examined before challenge, their baseline values were biased with respect to challenge treatment before treatment was applied. However, the lack of a significant main effect due to diet at 8 woa for blood pH and glucose concentration, along with the other 15 blood variables, indicate that the baseline data with respect to dietary treatment were unbiased, allowing for real dietary effects to be accurately assessed. In conclusion, layer pullets challenged with R_lowMG undergo a stress response associated with changes in various physiological blood variables, and a decrease in pH and increase in carbon dioxide partial pressure, in association with a lack of change in bicarbonate, indicates that the stress response caused by the R_lowMG challenge was associated with respiratory acidosis. Nevertheless, feeding XPC did not influence the effects of challenge treatment on these postchallenge physiological blood values.

Effects in broiler hens of genetic lines differing in fertility, biotin supplementation, and age on relative abundance of oviductal transforming growth factor-β and carbonic anhydrase mRNA transcripts

There was evaluation of effects of biotin administration on oviductal abundance of transforming growth factor-β (TGF-β) and carbonic anhydrase (CA) mRNA transcript in younger and older broiler hens of relatively lesser and greater fertility lines. Additionally, effects of biotin supplementation on attenuation of age-related subfertility were evaluated. Hens from the relatively greater (Line D, n = 60) and lesser (Line B, n = 60) fertility rate line were randomly assigned to three treatment groups. Biotin was not or was administered in drinking water from 30 to 33 (younger age) and 53 to 56 (older age) wk of age to have access to no biotin (T₀), or 0.3 (T₁), or 0.45 (T₂) mg/L of biotin. There was assessment the relative oviductal abundances of TGF-β and CA mRNA transcript abundances. Supplemental biotin and age had no effect on the relative abundance of oviductal TGF-β mRNA transcript in hens of Line D. There, however, was a ten-fold greater abundance of TGF-β in hens of the T₀ group of Line B compared with Line D. Relative abundance of TGF-β mRNA transcript was greater in younger hens of Line B; however, biotin supplementation of older hens of the T₂ group of Line B resulted in a similar TGF-β abundance to that of younger hens. Inconstant with the TGF-β abundance, CA abundance in hens of Line B was not affected by supplemental biotin or bird age. Overall, differences in TGF-β or CA abundances did not affect fertility of broiler hens.

Growth and humoral immune effects of dietary Original XPC in layer pullets challenged with Mycoplasma gallisepticum

Effects of dietary Original XPC (XPC) in commercial layer pullets challenged with the virulent, low passage R strain of Mycoplasma gallisepticum (R_low MG) were investigated. Hy-Line W-36 pullets sourced from MG-clean breeders were fed a basal diet with or without (CON) XPC (1.25 kg/metric ton) from hatch until 12 wk of age (woa). At 8 and 10 woa, half of the birds in each dietary treatment were challenged with R_low MG. Body weight was recorded at 3, 8, and 12 woa, and ovary, ceca, and bursa weights were recorded at 3 and 12 woa. Blood samples were taken immediately before the initial R_low MG challenge at 8 woa and again at 12 woa to test for IgM and IgG antibody production against MG. All birds were evaluated for MG lesion scores at 12 woa. Regardless of challenge, inclusion of XPC in the diet did not significantly alter BW at 3 or 8 woa or relative organ weights at 3 or 12 woa. However, at 12 woa, BW of XPC-fed birds, regardless of challenge was significantly (P = 0.0038) heavier than CON by 25.7 g. All birds tested negative for MG antibodies before the 8 woa challenge. Respective percentage serum plate agglutination and ELISA positive birds at 12 woa were 0 and 0% (CON, nonchallenged), 1.4 and 0% (XPC, nonchallenged), 100 and 47.2% (CON, challenged), and 100 and 50.0% (XPC, challenged). Diet did not significantly affect ELISA titers, but they were significantly (P < 0.0001) increased due to challenge. Furthermore, lesion scores were significantly higher for R_low MG-challenged birds (P = 0.0012), and dietary treatment with XPC in challenged birds numerically reduced MG lesion scores from 0.278 to 0.194. In conclusion, although dietary XPC did not significantly alter the humoral immune response, antibody titer levels, or severity of MG lesions in layer pullets that were or were not challenged with R_low MG, it led to an increase in their rate of growth through 12 woa.

Effects of stage of broiler embryo development on coccidiosis vaccine injection accuracy, and subsequent oocyst localization and hatchling quality

Control of coccidiosis in broiler chickens continues to pose challenges to commercial poultry producers, especially in an era of increased consumer demand for antibiotic-free broiler production. As a result, coccidiosis vaccines are now commonly used in rotation programs to achieve effective coccidiosis control. Inovocox EM1 vaccine (EM1) is a coccidiosis vaccine that allows for earlier immune acquisition through oocyst cycling, which reduces the effects of wild-type coccidia. The EM1 vaccine is administered to embryonated broiler hatching eggs between 18 and 19 D of incubation (doi). In the U.S., commercial broiler hatcheries vaccinate embryonated eggs at either 18.5 or 19 doi. However, it is unclear whether a difference in embryo age at the time of in ovo injection can impact the actual site of vaccine delivery. In addition, it is unclear where oocysts eventually become localized within the embryo following the in ovo injection of EM1. Therefore, the objective of this study was to determine the effects of stage of embryonic development on the actual deposition site of the EM1 vaccine oocysts when they are in ovo injected and to subsequently investigate the movement and eventual location of EM1 oocysts after in ovo injection. Because all eggs were injected at the same time, a 12-h difference in set time was a means to derive 18.5 and 19.0 incubation age of injection (IAN) treatments. The experimental design was a 3 injection treatment (noninjected, diluent-injected, and vaccine-injected) × 2 IAN factorial. There was a significant main effect of IAN on site of vaccine oocysts delivery, and subsequent hatching chick quality. Qualitative histological evaluation revealed the oral uptake of vaccine oocysts through the amnion, with their subsequent presence in the gizzard and intestinal lumen by 24 to 36 h postinjection. In conclusion, physiological development influenced the site of injection, and oocysts imbibed along with the amniotic fluid in late stage broiler embryos are subsequently transported to the gastrointestinal tract.

Occurrence of horizontal transmission in layer chickens after administration of an in ovo strain F Mycoplasma gallisepticum vaccine1,2,3

In ovo vaccination is currently being considered as a means of delivery for live Mycoplasma gallisepticum (MG) vaccines. This study was performed to determine the transmissibility of strain F MG (FMG) from in ovo-vaccinated chicks to non-vaccinated pen mates. Eggs from an MG clean flock were incubated together for 18 D, at which point all live embryonated eggs were either not injected or administered a dilution of an FMG vaccine at 106 CFU per dose, 1 × 104 CFU per dose, 1 × 102 CFU per dose, or 1 CFU per dose. Non-injected eggs were hatched in a separate incubator. Ten non-injected, sentinel birds, and 1 in ovo-vaccinated FMG chick were placed in each of 32 isolation units located in 2 replicate rooms (8 replicates per dose). At 6 wk of age, surviving birds that had been vaccinated in ovo were removed, swabbed for FMG detection by PCR, and bled for serum plate agglutination (SPA) and ELISA testing for the presence of antibodies against MG (1, 2, 6, and all 8 in ovo-vaccinated chicks in the 106, 104, 102, and 1 CFU dosages). At 12 wk of age, the remaining sentinel birds were likewise sampled. No sentinel birds died. The in ovo-vaccinated birds that survived to 6 wk were serologically positive except for 5 birds in the 1 CFU treatment. The percentages of MG-positive sentinel birds and sentinel birds with antibody production against MG at 12 wk from each unit were not different between all MG dosages (P = 0.48, PCR; P = 0.77, SPA; P = 0.85, ELISA). Body weights of the in ovo-vaccinated chicks at 6 wk of age (P = 0.43) and the sentinel birds at 12 wk of age (P = 0.95) were each not affected by FMG treatment. These findings indicate that layer chickens in ovo vaccinated with a live-attenuated FMG vaccine were capable of transmitting FMG to other chicks with which they were in direct contact.

Effects of in ovo injection of L-ascorbic acid on growth performance, carcass composition, plasma antioxidant capacity, and meat quality in broiler chickens1,2,3

The current study was designed to investigate the effects of the in ovo injection of different dosages of L-ascorbic acid (AA) on posthatch growth performance, carcass characteristics, plasma antioxidant capacity, and meat quality in broiler chickens. A total of 2,220 Ross 708 broiler hatching eggs containing live embryos at 17 D of incubation were subjected to 1 of 6 treatments (trt): non-injected control, saline-injected control, or saline containing 3, 6, 12 or 36 mg of AA. An Inovoject m semi-automatic multi-egg injector was used to inject a 100 μL volume of sterile saline (0.85%) alone or containing the different AA dosage into each egg. After hatch, 14 male hatchlings from each trt group were randomly selected and placed in each of 10 replicate floor pens for growth performance evaluation through 45 D posthatch. Chicks from the 3 and 6 mg AA trt groups had a higher average daily BW gain and a higher feed intake compared to the saline-injected control group during the grower phase. Chicks in the 12 mg AA trt group exhibited a better feed efficiency in the late finisher phase and the entire growing phase than those in the saline-injected control group. Higher thigh and leg percentages were observed in chicks from the 3 and 6 mg AA trt groups than in the non-injected control group. Compared to the non-injected or saline-injected control groups, birds in the 12 mg AA trt group were observed to have a lower plasma malondialdehyde content during the grower and finisher phases, and breast muscle tenderness was elevated in chicks from the 36 mg AA trt group. Taken together, these results suggest that the in ovo injection of AA (3 to 12 mg per egg) have lasting positive effects on the posthatch growth, leg muscle development, and systemic antioxidant capacity of broilers. Higher injected dosages of AA (36 mg per egg) may also have the potential to improve broiler meat quality.

Sperm characteristics of Chukar partridge (Alectoris chukar) breeders as affected by the addition of calcitriol to the semen extender

This study was carried out to determine the effect of supplementing the semen extender with calcitriol on in vitro sperm characteristics in Chukar partridges. A total of 60 male Chukar partridges were habituated for semen collection by abdominal massage. Pooled ejaculates from several males were extended (1 to 5 v/v ratio) in the Sexton's diluent containing 0, 24, 48, 96, or 192 μg calcitriol/mL. These concentrations represented 0-, 2-, 4-, 8-, and 16-fold levels of the mean seminal calcitriol concentration, respectively. A total of 12 subsamples from each treatment group were kept at 4 to 5°C or 19 to 24°C for 4, 24, or 48 h. The percentages of motile sperm, live sperm, abnormal sperm, incidence of hypoosmotic swelling (HOS), and thiobarbituric acid reactive species (TBARS) concentrations were determined. The data were analyzed by the xtmixed procedure of STATA software. The percentages of motile sperm, live sperm, abnormal sperm, and seminal TBARS were affected by calcitriol (P < 0.05). There was no effect of treatments on HOS (P > 0.05). There was an interaction effect between calcitriol, storage time, and storage temperature on sperm motility, sperm viability, and seminal TBARS. Supplementation of the diluent with 96 μg calcitriol/mL resulted in the highest sperm motility at 4°C. Also, the same treatment group recorded the highest sperm viability and lowest seminal TBARS at 19 to 24°C. Supplementing the diluent with calcitriol had beneficial effects on spermatozoa; however, the fertility rate of spermatozoa extended in calcitriol-supplemented diluent needs to be determined before the procedure can be recommended for use in artificial insemination programs.

Comparative effects of in ovo versus subcutaneous administration of the Marek's disease vaccine and pre-placement holding time on the intestinal villus to crypt ratios of Ross 708 broilers during early post-hatch development1,2,3

Villus to crypt ratio (VCR) is used to quantify the microanatomical response of the intestine to various treatments. In early age chickens, comparative effects of the in ovo (i.o.) and s.c. methods of administration (moa) of the Marek's disease (MD) vaccine on 2 types of measurement of small intestinal VCR at 0 and 4 h post-hatch (poh) were investigated. The effects of moa and 4 and 18 h pre-placement holding times (pht) on the VCR measurements at 168 h (7 d) poh were also investigated. In the jejunum of the small intestine, a standard method for VCR determination, based on 10 villus and crypt length measurements, was utilized for the calculation of villus to crypt length ratio (VCLR). In that same region, a single histomorphometric determination of the crypt and total mucosa areas using image analysis software was also used. Subtraction of the crypt area from the total mucosa area provided the villus area, allowing for calculation of the villus to crypt area ratio (VCAR). Across 0, 4, and 18 h of poh bird age, the VCLR of birds that received an s.c. vaccination was higher in comparison to that of those that received an i.o. vaccination. The highest and lowest VCAR values were observed in the s.c. treatment at 0 h poh and in the i.o. treatment at 4 h poh, respectively. Furthermore, at 168 h poh, VCLR values in the 18 h pht and s.c. vaccination group were higher than those in the 4 h pht and s.c. vaccination or 18 h and i.o. vaccination groups. In conclusion, the effects of pht and MD vaccine moa on VCR were dependent on the use of either the VCLR or VCAR method of measurement. However, regardless of method, s.c. injection overall led to a higher VCR through 4 h poh in Ross 708 broilers, and the effects of moa on VCLR at 168 h were influenced by pht.

Early post-hatch survival and humoral immune response of layer chickens when in ovo vaccinated with strain F Mycoplasma gallisepticum,

Commercial layer hens reared on multi-age hen complexes are vaccinated during pullet rearing to combat production losses due to the bacteria Mycoplasma gallisepticum (MG). In this study, the potential to in ovo vaccinate layer chickens against MG was investigated. Layer embryos were administered a dosage of a live attenuated strain F MG (FMG) vaccine at 18 d of incubation and raised for 6 wk for initial post-hatch evaluation in 2 replicate trials. Treatments included control non-injected eggs, eggs injected with diluent, a non-diluted dosage, a 10-2 dilution, a 10-4 dilution, and a 10-6 dilution. A subset of chicks were swabbed for detection of FMG in the trachea at hatch. At 6 wk of age, birds were swabbed again for FMG detection and a blood sample was tested for MG antibody production. Hatch was depressed in the non-diluted dose group (P < 0.0001). Strain F MG was detected at hatch in the trachea in each FMG injection treatment, with decreasing numbers of positive chicks in the lower dosage groups. Mortality during the first 2 wk post-hatch was 3.5% (trial 1) and was 11.7% (trial 2) in the 10-6 dilution treatment, with all other FMG treatments experiencing a high rate of mortality (>50%). Birds in the in ovo FMG treatments had detectable FMG and antibody production at 6 wk. There were no differences in percentage positive birds (P > 0.3 for all tests) or ELISA titers (P = 0.079) between the FMG treatments. Body weight at 6 wk of age was diminished with increasing FMG dose (P < 0.0001). The lowest dose tested was found to be the most practical, causing the least mortality, least weight loss, and a humoral immune response in the majority of the birds. Further work is needed to evaluate how this in ovo vaccine, promoting immunity earlier, would compare to a standard post-hatch vaccination against an MG challenge scenario through a lay cycle.

In ovo applications in poultry: A review,

The various methods employed for the in ovo administration of different materials for promoting the health and productivity of poultry are discussed in this review article. The amnion has proven to be an effective site for injection and the timing of in ovo injection has commonly occurred at transfer. However, the volumes and dosages or concentrations of the materials administered vary depending on bird type, egg size, timing and site of injection, incubation system and regimen, and the type of material. Both manual and automated injections have been shown to be effective. Nevertheless, commercial application mandates automation. Materials described in the literature over the past 20 years or more for in ovo use in avian species include vaccines, drugs, hormones, competitive exclusion cultures and prebiotics, and supplemental nutrients. Vaccines approved for in ovo delivery include those for Marek's disease, infectious bursal disease, fowl pox, Newcastle disease, and coccidiosis. Some of the materials listed above have been shown to be viable candidates for enhancing immunity and for promoting embryonic and posthatch development. Several reports have indicated that probiotics may be effectively used to fight intestinal bacterial infections, and folic aid, as well as egg white protein and various amino acids, including L-arginine, L-lysine, L-histidine, HMB, and threonine alone or in combination, have been shown to benefit embryonic development or posthatch performance. Furthermore, CpG oligodeoxynucleotides, vitamins C and E, and thyme and savory have the potential to enhance immunity, carbohydrates can be used to increase tissue glycogen stores, and creatine can be used to promote muscle growth. Trace minerals and vitamin D3 have shown potential to improve bone strength, and potassium chloride may be an effective alternative electrolyte in vaccine diluent. The in ovo application of these and other materials will continue to expand and provide further benefits to the poultry industry.

Effects of in ovo injection of different doses of coccidiosis vaccine and turn-out times on broiler performance,

Inovocox EM1 vaccine (EM1) is hatchery-applied via in ovo injection for the control of coccidiosis in broiler chickens. Effects of 3 in ovo injection treatments (INT) and 2 turn-out times (TOT) on the hatching chick quality variables and 35 d posthatch performance of Ross × Ross 708 broilers were investigated. In a single-stage incubator, 1,440 hatching eggs were randomly distributed among 3 INT groups on each of 8 tray levels. At 19 d of incubation (doi), embryonated eggs were subjected to one of the following INT by in ovo injection: noninjected control; 1 × dose of EM1; 10 × dose of EM1. On 21 doi, hatchability of injected eggs (HI), hatching body weight (HBW), and hatching chick quality variables were determined. Additionally, for the grow-out phase, birds belonging to each INT were randomly subjected to a 7 or 10 d TOT. Twenty chicks were initially placed in each of 48 floor pens (6 INT × TOT combination groups × 8 replications) for growth performance evaluation from 0 to 35 d posthatch. The main effect of INT on hatching chick quality variables, as well as the main and interactive effects of INT and TOT on various grow-out performance variables were determined. Although there was no significant INT effect on HI or HBW, significant INT effects on chick total BW, yolk-free BW, and yolk sac weight were observed. There were significant INT effects on BWG and FCR in the 21- to 28-d posthatch interval, as well as on BWG and FCR in the 0- to 35-d posthatch interval. There was no main effect of TOT or interactive effect of INT and TOT on BW and other performance variables from 0 to 35 d posthatch. There was a significant main effect of INT on relative intestine weight at 28 d posthatch. In conclusion, the injection of EM1 vaccine at a 10 × dose may affect hatching chick quality variables and growth performance up to 35 d posthatch.

Comparison of two methods for determination of intestinal villus to crypt ratios and documentation of early age-associated ratio changes in broiler chickens,

The determination of intestinal villus to crypt ratios (VCR) is a common method utilized to evaluate effects of various diet regimens on gut microanatomy and for the histologic quantification of intestinal responses to disease processes. Two methods for the determination of small intestinal VCR were compared in early age chickens. A standard method for VCR determination based on 10 villus and crypt length measurements in the jejunal region of the small intestine was employed for the calculation of villus to crypt length ratio (VCLR). That method was compared to a new approach based on a single histomorphometric determination of the crypt and total mucosal areas using image analysis software. Subtraction of the crypt area from the total area provided the villus area and allowed for the subsequent calculation of villus to crypt area ratio (VCAR). At 4 and 18 h posthatch, VCLR was higher than that of VCAR, but there was no significant difference between VCLR and VCAR at 0 h (hatch) and at 168 h (d 7) posthatch. Nevertheless, the pattern of age-associated changes for VCLR and VCAR were comparable throughout the early posthatch period. Furthermore, the new method used in determining VCAR is subject to less human error, allows for an appreciable reduction in the number of measurements required, and facilitates a larger intestinal segment evaluation. Standard linear measurements require the selection of variable numbers of villi and crypts, whereas the area method only requires selection of a single region that incorporates numerous villi and crypts of variable sizes in providing a less subjective approach. This is particularly advantageous in studies on intestinal disease conditions resulting in marked multifocal variation in villus stature. This study further documented age-associated changes occurring in the VCR of the small intestine during the early posthatch period. Across the 2 methods used for VCR determination, a major and highly significant reduction in the VCR was observed to occur between 18 h and 168 h posthatch.

Symposium: avian embryo nutrition and incubation

The embryonic period represents approximately 33 percent of the total productive life of modern broilers and is very important for attaining quality broiler performance at marketing. In this symposium, recent developments in pre-hatch broiler development were discussed with special focus on maternal nutrition, in ovo nutrition, and the regulation and monitoring of the incubational environment. The symposium was concluded with discussion about the implementation of future innovations in incubation technology.

Comparative effects of in ovo versus subcutaneous administration of the Marek's disease vaccine and pre-placement holding time on the post-hatch performance of Ross 708 broilers1,2,3

Effects of 2 types of methods of administration (moa; in ovo or s.c.) of the Marek's disease (MD) vaccine and 4 and 18 h pre-placement holding times (pht) on the performance of male broilers through 48 d of age were investigated. Ross 708 broiler hatching eggs (3,900) were either in ovo-vaccinated at 18 d of incubation or chicks from eggs that were not in ovo-injected were vaccinated s.c. at hatch, and chicks from each moa group were held for one of the 2 pht. In ovo injections (50 μL) were delivered by a commercial multi-egg injector and s.c. injections (0.2 mL) were delivered by an automatic pneumatic s.c. injector. Sixteen birds were assigned to each of 15 replicate floor pens belonging to each of the 4 moa and pht combination groups. Mortality and BW gain were determined at weekly intervals, and feed consumption and conversion were determined in the zero to 14, 14 to 28, 28 to 42, and 42 to 48 d age intervals. No interactive effects between moa and pht were observed for any variable, and mortality was not significantly affected by moa or pht. The 14 to 28 d feed consumption and 14 to 21 d BW gain of s.c.-vaccinated birds were lower than that of in ovo-vaccinated birds, and the increase in pht from 4 to 18 h decreased feed consumption through 28 d post hatch and BW gain through 35 d post hatch. Overall, the performances of male Ross 708 broilers through 48 d of age in response to in ovo and s.c. injections of the MD vaccine were comparable, and delays in hatchling placement should be less that 18 h in duration. Furthermore, despite the decrease in BW gain through 35 d associated with the reduction in feed consumption through 28 d in response to the 14 h increase in pht, in ovo injection did not exacerbate the effect of the increase in pht.

Comparative effects of in ovo versus subcutaneous administration of the Marek's disease vaccine and pre-placement holding time on the processing yield of Ross 708 broilers

Effects of the in ovo (i.o.) or subcutaneous (s.c.) method of administration (moa) of the Marek's disease (MD) vaccine and 4 or 18 h pre-placement holding time (pht) on the processing yield of male broilers through 49 d of age (doa) were investigated. Ross 708 broiler hatching eggs (3,900) were either i.o.-vaccinated at 18 d of incubation or chicks from eggs that were not i.o.-vaccinated were s.c.-vaccinated at hatch. The i.o. injections (50 μL) were delivered by a commercial multi-egg injector and s.c. injections (200 μL) were delivered by an automatic pneumatic s.c. injector. The pht was imposed on chicks after vaccination. Sixteen birds were initially assigned to each of 15 replicate floor pens belonging to each of the moa and pht combination groups and were grown out through 48 doa. At 48 doa, 6 birds were randomly selected from each replicate pen and were weighed and fasted for 16 h before being processed. At 49 doa, whole carcass, fat pad, breast muscle, and tenders muscles weights were recorded. Whole carcass weight as a percentage of live BW, and fat pad, breast muscle, and tenders muscles weights as percentages of both live and whole carcass weights were calculated. Upon subjection of the data to a 2 × 2 factorial analysis, only a main effect due to moa was observed for tenders muscles weight as a percentage of live and whole carcass weights. Tenders muscles weight as a percentage of both live (P ≤ 0.010) and whole carcass (P ≤ 0.004) weight was higher in birds hatched from eggs that received i.o. rather than s.c. vaccinations. In conclusion, in comparison to s.c. vaccination, i.o. vaccination increased relative tenders weight yield, whether or not broilers were held for 4 or 18 h prior to placement. Therefore, with regard to broiler processing yield, i.o. and s.c. vaccinations were safe for the administration of the MD vaccine, with i.o. vaccination displaying a slight potential advantage.

Effects of embryo temperature estimation methodology on the determination of eggshell conductance values in Ross 708 broiler hatching eggs with consideration given to eggshell pigmentation variation

In a preliminary experiment, the influence of pigment color variation on the temperature readings of the shells (EST) of live embryonated Ross 708 broiler hatching eggs was tested. Prior to set, eggshell color in L*, a*, and b* coordinates were measured at the equator of each egg. Eggshell pigmentation was found not to influence EST from zero through 18 d of incubation (DOI). In a subsequent experiment, EST, as well as air cell (ACT) and cloaca (CLT) temperature measurements were used for the calculation of absolute (GH2O) and specific (gH20) eggshell conductance values for these same types of eggs. An infrared thermometer was used to determine EST from zero to 19 DOI, ACT was measured using a transponder from 12 to 19 DOI, and CLT was determined using a transponder at 4:00 PM at 19 DOI. In the 12 to 19 DOI interval, the values for GH2O as well as for gH20 that were calculated using either EST or ACT were significantly correlated (r ≥ 0.99; P < 0.0001). A similar correlation level for both GH2O and gH20 was likewise observed in the 10:00 AM to 10:00 PM time period at 19 DOI when either EST, ACT, or CLT was used. However, in the 12 to 19 DOI interval, calculated GH2O and gH20 values based on ACT were significantly different from those based on EST. In addition, a significant difference in calculated GH2O and gH20 values resulted when ACT was used rather than when EST or CLT was used in the 10:00 AM to 10:00 PM time period at 19 DOI. In both time periods, GH2O and gH20 values calculated using ACT were significantly lower than those derived using the other 2 types of measurements. These findings suggest that although EST was not affected by shell coloration, because ACT more closely reflects embryo body temperature, it should be used to more accurately calculate the GH2O and gH20 of Ross 708 broiler hatching eggs.

Relationships of eggshell, air cell, and cloacal temperatures of embryonated broiler hatching eggs during incubation

The relationships of eggshell, air cell, and embryo cloacal temperatures in Ross × Ross 708 broiler hatching eggs were determined. Twenty eggs were weighed and set on each of 3 tray levels of a single incubator. Eggshell temperature (EST) of the eggs were recorded once in the morning (AM) and afternoon (PM) between 0 and 19 d of incubation (DOI) using an infrared thermometer (IRT). All eggs were candled and a transponder was implanted in the air cell of eggs containing live embryos (12 per tray level) at 12 DOI. At 19 DOI, transponders were implanted in the cloaca of live embryos from those same eggs. Air cell temperature (ACT) and EST readings were recorded once in the AM and PM between 12 and 19 DOI, and ACT and cloaca temperature (CLT) readings were recorded every 6 h between 19 and 21 DOI. The EST and ACT readings between 13 and 19 DOI were positively correlated. However, their respective mean temperatures between 13 and 19 DOI differed. The EST and ACT were not significantly influenced by tray level. Nevertheless, a main effect due to location (eggshell vs. air cell), and an interaction between DOI and time of day (AM and PM) in the 13 to 19 DOI interval were observed. Furthermore, an interaction was observed between location (air cell and cloaca) and the 6 h sequential time periods in the 19 to 21 DOI interval. However, across the entire 19 to 21 DOI interval, mean ACT and CLT were not significantly different, and were positively correlated. These data suggest that ACT readings are higher than those of EST during the last half of incubation, and that between 13 and 19 DOI, ACT readings may have the potential for use as a minimally invasive method by which to more accurately estimate the true core body temperature of broiler embryos. The effects of this method on hatchability and post-hatch performance need determination to better establish its practicality.

Effects of different vaccine combinations against Mycoplasma gallisepticum on the digestive and reproductive organ characteristics of commercial egg-laying hens

Mycoplasma gallisepticum (MG) is a major and economically significant pathogen of avian species. When administered before lay, F-strain MG (FMG) can reduce egg production during lay, but the ts-11 strain of MG (ts11MG) does not exert this effect. Two trials were conducted to determine the effects of pre-lay vaccinations of ts11MG, MG-Bacterin (MGBac), or their combination, in conjunction with an FMG vaccination overlay after peak production on the digestive and reproductive organ characteristics of Hy-Line W-36 layers housed in biological isolation units (4 units per treatment, 10 birds per unit). The following vaccination treatments were administered at 10 wk of age (woa): 1) Control (no vaccinations); 2) MGBac; 3) ts11MG; and 4) ts11MG and MGBac combination (ts11MG+MGBac). At 45 woa, half of the birds were vaccinated with a laboratory stock of high passage FMG. In both trials, parameters determined in 4 birds per unit at 55 woa included: BW; fatty liver hemorrhagic syndrome incidence; mean number of mature ovarian follicles; ovarian, oviduct, and small intestine weights; and the weights and lengths of the various portions of the oviduct and small intestine. Treatment effects were observed for the weights of the entire small intestine and the duodenum, jejunum, and ileum, as percentages of BW; and for vagina weight as a percentage of total oviduct weight. In general, the weights of the small intestine and its 3 components were increased in response to the FMG vaccine that was administered at 45 woa. An FMG vaccination at 45 woa may increase relative intestine weight in layers; however, use of a prelay MGBac vaccine alone or in combination with ts11MG, with or without an FMG overlay, does not affect the gross characteristics of their digestive and reproductive organs, and may be used without having an adverse effect on their performance, as was observed in a previous companion study.

Effects of different vaccine combinations against Mycoplasma gallisepticum on the internal egg and eggshell characteristics of commercial layer chickens 1,2,3

Live F-strain Mycoplasma gallisepticum (FMG) vaccines are presently being used to help control field-strain MG outbreaks. However, they may exert some adverse effects on egg production. Live strains of MG of lesser virulence as well as killed vaccines have little or no effect on egg production, but afford lower levels of protection. This has led to research investigating their use in combination with a subsequent overlay vaccination of FMG given later in the production cycle. In the present study, 2 trials were conducted to investigate the effects of prelay vaccinations of live and killed MG vaccines or their combination, in conjunction with an FMG vaccine overlay after peak production, on the egg characteristics of commercial layers. The following vaccination treatments were administered at 10 wk of age (woa): 1) unvaccinated (Control), 2) MG-Bacterin (MGBac) vaccine, 3) ts-11 strain MG (ts11MG) vaccine, and 4) MGBac and ts11MG combination (MGBac + ts11MG). At 45 woa, half of the birds were overlaid with an FMG vaccine. In each trial, internal egg and eggshell parameters including egg weight (EW), Haugh unit score (HU), eggshell breaking strength (EBS), percentage yolk weight (PYW), percentage albumen weight (PAW), percentage eggshell weight (PSW), eggshell weight per unit surface area (SWUSA), percentage yolk moisture (PYM), and percent total lipids (PYL) were determined at various time periods between 21 and 52 woa. At 28 woa, SWUSA was lower in the ts11MG and MGBac + ts11MG groups compared to the Control group. Conversely, at 43 woa, SWUSA was higher in the ts11MG than in the MGBac group. Between 23 and 43 woa, PYL was higher in the MGBac and ts11MG groups in comparison to the Control group. In conclusion, vaccination with MGBac alone or in combination with ts11MG at 10 woa with or without an FMG vaccine overlay at 45 woa does not adversely affect the internal egg or eggshell quality of commercial layers throughout lay.

Effects of live and killed vaccines against Mycoplasma gallisepticum on the performance characteristics of commercial layer chickens

Different vaccine strains of Mycoplasma gallisepticum have been used on multiple-age commercial layer farms in an effort to protect birds against virulent field-strain infections. Use of the F-strain of M. gallisepticum (FMG), as an overlay vaccine during lay, may be necessary because of the lower level of protection afforded by M. gallisepticum vaccines of low virulence given before lay. Two replicate trials were conducted to investigate effects of live and killed M. gallisepticum vaccines administered individually and in combination before lay, in conjunction with an FMG vaccine overlay after peak egg production (EP), on the performance characteristics of commercial layers. The following treatments were utilized at 10 wk of age (woa): 1) control (no vaccinations); 2) ts11 strain M. gallisepticum (ts11MG) vaccine; 3) M. gallisepticum-Bacterin vaccine (MG-Bacterin); and 4) ts11MG and MG-Bacterin vaccines combination. At 45 woa, half of the birds were overlaid with an FMG vaccine. Hen mortality, BW, egg weight, percentage hen-day EP, egg blood spots, and egg meat spots were determined at various time periods between 18 and 52 woa. The data from each trial were pooled. Treatment did not affect performance in interval I (23 to 45 woa). However, during interval II (46 to 52 woa), the EP of control and MG-Bacterin-vaccinated birds that later received an FMG vaccine overlay was lower than that in the other treatment groups. Furthermore, treatment application reduced bird BW during interval II. Despite the effects on BW and EP, no differences were observed for egg blood or meat spots among the various treatments. It is suggested that the vaccination of commercial layers before lay with ts11MG, but not MG-Bacterin, may reduce the negative impacts of an FMG overlay vaccination given during lay. These results establish that the vaccination of pullets with ts11MG in combination with the vaccination of hens with an FMG overlay, for continual protection against field-strain M. gallisepticum infections, may be used without suppressing performance.

Effects of protein source and nutrient density in the diets of male broilers from 8 to 21 days of age on their subsequent growth, blood constituents, and carcass compositions

The effects of protein source and amino acid (AA) and AME levels in the diets of male broilers from 8 to 21 d of age on subsequent growth and blood and carcass traits were investigated in the current study. Fourteen Ross × Ross 708 male broiler chicks were randomly allocated to each of 80 floor pens arranged in a randomized complete block design. Each diet contained 1 of 2 dietary protein sources (high inclusion of distillers dried grains with solubles or high inclusion of meat and bone meal), 1 of 2 AA densities (moderate or 10% higher), and 1 of 2 AME densities (2,998 or 3,100 kcal/kg). Experimental diets were fed from 8 to 21 d of age, and common diets from 1 to 7 and 21 to 55 d of age. The higher AME density in high inclusion of meat and bone meal diets increased serum triglyceride and cholesterol levels on d 20. The dietary inclusion of high inclusion of distillers dried grains with solubles or lower levels of AA increased high-density lipoprotein cholesterol on d 20. Feeding the high-AA-density diet decreased feed intake without affecting BW gain, which resulted in a lower feed conversion ratio (FCR). A high-AME-density diet lowered feed intake but increased BW gain, which resulted in a lower FCR from 8 to 21 d of age. Feed intake, BW gain, FCR from 21 to 54 d of age, and carcass weight on 42 and 55 d of age were not affected by treatments from 8 to 21 d of age. However, early dietary manipulation from 8 to 21 d of age affected fat and meat yield at 42 and 55 d of age. Moreover, a high-AME diet decreased feed cost per carcass weight gain from 8 to 55 d of age. In conclusion, high AA or AME densities during the grower phase, from d 8 to 21 of age, may improve growth during the grower feeding phase, but may also affect meat yield during the latter grow-out phases. Furthermore, high-AME diets from 8 to 21 d of age may save on feed costs for meat production.

Improvements in semen quality, sperm fatty acids, and reproductive performance in aged Cobb 500 breeder roosters fed diets containing dried ginger rhizomes (Zingiber officinale)

Exposure to high levels of polyunsaturated fatty acid predisposes spermatozoa to lipid peroxidation, resulting in their decreased fertility. Ginger powder (GP), which is high in antioxidative compounds, was fed to aged breeder roosters to improve their reproductive performance. Seventy-five 52-wk-old Cobb 500 breeder roosters randomly received either 0 (GP0), 15 (GP15), or 30 (GP30) g of GP/kg of diet for 14 consecutive wk, during which time their seminal characteristics were evaluated every 2 wk. At the end of the trial, semen samples were tested for determination of sperm fatty acid (FA) concentration and seminal plasma total antioxidant capacity. Furthermore, sperm penetration was assayed, and using 225 artificially inseminated hens, fertility and hatchability rates were determined. Dietary GP improved sperm forward motility, live sperm percentage, and sperm plasma membrane integrity. These were associated with a decrease in the percentage of abnormal sperm. The seminal TBA reactive species concentration was lower in birds belonging to the GP30 treatment in comparison with those in the GP15 and GP0 treatments. The feeding of GP resulted in overall decreases and increases in sperm saturated and unsaturated FA, respectively. The n-6:n-3 FA ratio of sperm was decreased in the GP30 group in comparison with controls. The highest levels of sperm C20:4(n-6) and C22:6(n-3) FA were recorded in the GP15 and GP30 treatments, respectively. A higher percentage of sperm C22:4(n-6) FA was found in GP-fed roosters. Seminal plasma total antioxidant capacity was considerably improved by the GP15 and GP30 treatments. Further, a higher number of perivitelline membrane sperm penetration holes was recorded for the GP30 treatment in comparison with the GP15 and GP0 treatments. Interestingly, although hatchability, chick quality, and embryonic mortality were not affected by dietary treatment, fertility rate was improved by the feeding of GP. In conclusion, dietary GP improved most of the seminal characteristics evaluated in aged roosters of this study, suggesting that it has potential for use in attenuating age-related subfertility in senescent male commercial broiler breeders.

Effects of nicarbazin on the blood glucose and liver glycogen statuses of male broilers

Nicarbazin (NCZ), an effective anticoccidial widely used by the global broiler industry, is known to produce some side effects in broilers. Recent field observations have suggested that NCZ could be associated with spiking mortality syndrome, a disease of uncertain etiology that is most commonly characterized by hypoglycemia. In turn, 2 trials were conducted to investigate the effects of NCZ on the blood glucose levels and liver glycogen content of Ross × Ross 708 male broilers. In 6 of 12 pens beginning at 1 d of age, NCZ was added to basal broiler diets at a rate of 125 mg/kg, and the other 6 pens were control pens in which birds received salinomycin instead of NCZ, at a rate of 66 mg/kg. Feed and water were provided ad libitum, feed was closely monitored in all pens to avoid shortages, no coccidial challenge was imposed, and room temperature never exceeded 29.4°C. At the end of the second trial, a photoperiod increase from 8L:16D to 24L:0D was imposed in an effort to induce stress due to feed engorgement. In response to NCZ in trial 1, 0 to 28 d feed conversion and relative liver weights on d 21 and 28 were higher, whereas 0 to 28 d cumulative BW gain was lower. In response to NCZ in trial 2, 0 to 13 d feed conversion was higher, whereas 0 to 13 d cumulative BW gain was lower. The added NCZ increased blood glucose on d 13 in trial 2, but did not affect at any time the liver constituents analyzed in both trials. In conclusion, the uninterrupted feeding of NCZ at 125 mg/kg in the starter and grower diets of male Ross × Ross 708 broilers increased feed conversion and reduced BW gain, but despite an increase in relative liver weight on d 21 and 28 posthatch, liver glucose and glycogen concentrations were not affected.

Physiological relationships of the early posthatch performance of broilers to their embryo and eggshell characteristics

Relationships between physiological parameters of early posthatch chicks with their corresponding egg and embryo parameters were examined in progeny of young broiler breeders. Four hundred and 80 broiler hatching eggs that were obtained from a 29-wk-old Ross 308 breeder flock were incubated on 8 replicate tray levels of an incubator until hatch. Between 10.5 and 18.5 d of incubation, internal (T(emb)) and external (T(ext)) egg temperatures were recorded twice daily using temperature transponders. Beginning at 18.5 d, the eggs were individually monitored for hatch every 12 h. Average T(emb), T(ext), and average daily incubational egg weight loss (EWL) for the 10.5- to 18.5-d incubation period were used to calculate eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to 100 g of set egg weight basis), and a G(H2O) constant (K(H2O)) for each egg. Chicks were grown out for 10 d in pens of a single battery brooder. In each pen, on d 3 posthatch, carcasses, yolk sac, liver, and pipping muscle samples were collected from at least 2 chicks that hatched from eggs implanted with transponders for determination of their relative weights and moisture concentrations. Livers and pipping muscles were also analyzed for glucose, glycogen, fat, and protein concentrations. Yolk sac weight as a percentage of chick BW (YW) and its moisture concentration (YSM) were positively correlated with T(emb). Egg g(H2O) was positively correlated with chick carcass moisture concentration and its relative weight as a percentage of set egg weight, but it was negatively correlated with YW. The positive functional relationship between T(emb) and incubation length may be mediated via their common positive relationships to YSM. A negative correlation was observed between percentage EWL and relative BW on d 0 and 0.5 posthatch for chicks hatched from unimplanted eggs. The results suggest that a higher g(H2O) results in an increased metabolism of the broiler embryo, which subsequently increases growth and yolk sac absorption in broiler chicks through 3 d posthatch.

Comparative evaluation of air cell and eggshell temperature measurement methodologies used in broiler hatching eggs during late incubation

The current study was conducted to compare and contrast the uses of 2 devices (temperature transponder or infrared thermometer) and their locations (inner air cell membrane or outer eggshell surface) in Ross × Ross 708 broiler hatching eggs. The air cells of 14 embryonated and 10 nonembryonated eggs were implanted with temperature transponders on d 13.5 of incubation. Likewise, for these same eggs, eggshell surface temperature was detected with the use of transponders and an infrared thermometer. Temperatures were recorded every 12 h between 14.5 and 18 d of incubation, and graphs and corresponding regression values were used to track the temperatures over these time periods. The temperature readings using all methods in embryonated and nonembryonated eggs were positively correlated. In nonembryonated eggs, temperatures in the air cell and on the eggshell surface using transponders were higher than those on the eggshell surface using an infrared thermometer. Mean air cell temperature readings of embryonated eggs using transponders were higher than those of the eggshell, as determined with the use of transponders or an infrared thermometer. Furthermore, the differences in air cell temperature using transponders and eggshell temperature using an infrared thermometer in embryonated eggs increased with embryonic age. These readings confirmed increased embryo heat production during the incubational period examined. It was further concluded that when compared with actual embryo body temperatures determined in previous studies, the use of transponders in the air cells of broiler hatching eggs detected a higher and closer temperature than eggshell surface temperature. It is suggested that the air cell transponders in embryonated eggs circumvented the confounding effects of the thermal barrier properties of the eggshell and the flow of air across its surface.

Effects of in ovo injection of carbohydrates on somatic characteristics and liver nutrient profiles of broiler embryos and hatchlings

Effects of the in ovo injection of commercial diluent supplemented with dextrin or with dextrin in combination with various other carbohydrates on the somatic characteristics and liver nutrient profiles of Ross × Ross 708 broiler embryos and chicks were investigated. Results include information concerning the gluconeogenic energy status of the liver before and after hatch. Eggs containing live embryos were injected in the amnion on d 18 of incubation using an automated multiple-egg injector for the delivery of the following carbohydrates dissolved in 0.4 mL of commercial diluent: 1) 6.25% glucose and 18.75% dextrin; 2) 6.25% sucrose and 18.75% dextrin; 3) 6.25% maltose and 18.75% dextrin; and 4) 25% dextrin. Also, a noninjected control and a 0.4-mL diluent-injected control were included. Body weight relative to set egg weight on d 19 of incubation (E19) was increased by the injection of all carbohydrate solutions, and on the day of hatch was increased by the injection of diluent, sucrose and dextrin, and maltose and dextrin solutions. Hatchability of the fertilized eggs, residual yolk sac weight, and liver weight were not affected by any injection treatment; however, as compared with the 0.4 mL diluent-injected group, all of the supplementary carbohydrates, except for the glucose and dextrin combination group, increased liver glycogen and glucose concentrations on E19. Furthermore, all carbohydrates, except for the 25% dextrin treatment, decreased liver fat concentration on E19. From E19 to the day of hatch, liver glycogen concentrations dropped dramatically from an average of 3.2 to 0.6%. Despite treatment differences observed on E19 for liver glycogen, glucose, and fat concentrations, these differences were lost by the day of hatch. Nevertheless, liver glycogen and glucose concentrations were positively correlated on the day of hatch. In conclusion, the in ovo injection of various supplemental carbohydrates dissolved in 0.4 mL of commercial diluent altered the liver nutrient profile of Ross × Ross 708 broiler embryos before hatch. However, the subsequent pattern of energy utilization during the hatching process modified these effects.

Determination of embryonic temperature profiles and eggshell water vapor conductance constants in incubating Ross x Ross 708 broiler hatching eggs using temperature transponders

The comprehensive profiles of the internal and external temperatures of embryonated Ross × Ross 708 broiler hatching eggs during incubation were determined using temperature transponders, and eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to a 100 g set egg weight basis), and G(H2O) constants (K(H2O)) were calculated. On each of 8 replicate tray levels of an incubator, 2 nonembryonated and 4 embryonated eggs were each implanted with a transponder on d 10.5 of incubation for the determination of internal (air cell) temperatures of nonembryonated (T(nem)) and embryonated (T(emb)) eggs, respectively. In addition, 2 water-filled vials, each containing a transponder, were used on each tray level for the determination of the external microenvironment temperatures (T(ext)) of the embryonated and nonembryonated eggs. Between 10.5 and 18 d of incubation, incubator data logger temperatures were determined every 5 min; and incubator dry bulb temperature, T(ext), T(nem), T(emb), and the difference between T(emb) and T(nem) (T) were determined every 12 h. Over the days of incubation, regression coefficients for T(emb) and T were positive, whereas the regression coefficient for T(nem) was negative. There was a significant day of incubation × type of temperature measurement (T(ext), T(nem), and T(emb)) interaction for temperature. Between 13 and 18 d of incubation, mean values of T(emb) readings that were recorded every 12 h were consistently higher than those of T(ext) and T(nem), indicating the importance of air cell transponder implantation for the efficient estimation of broiler embryo temperature. Furthermore, mean values of the percentage of daily incubational egg weight loss, G(H2O), g(H2O), and K(H2O) of the embryonated eggs were 0.54 ± 0.019%, 14.4 ± 0.56 mg of H₂O/d per Torr, 25.0 ± 0.96 mg of H₂O/d per Torr per 100 g, and 5.20 ± 0.205, respectively. The results suggest that transponders may be implanted in the air cells of broiler hatching eggs to detect incubational variations in T(emb) and to subsequently calculate G(H2O), g(H2O), and K(H2O).

Effects of in ovo injection of carbohydrates on embryonic metabolism, hatchability, and subsequent somatic characteristics of broiler hatchlings

The effects of the in ovo injection of different carbohydrate solutions on the internal egg temperature (IT), hatchability, and time of hatch of embryonated Ross × Ross 708 broiler hatching eggs were determined. In addition, the BW, liver weight, yolk sac weight (YSW), and yolk-free BW (YFBW) of the embryos on d 19.5 of incubation and of the chicks on day of hatch were determined. Eggs containing live embryos were injected in the amnion on d 18.5 of incubation using an automated multiple-egg injector. Solution injections delivered 1.2 mL of physiological saline (0.85%) alone or with a supplemental carbohydrate. The following supplemental carbohydrates were separately dissolved in saline at a concentration of 0.3 g/mL: glucose, fructose, sucrose, maltose, and dextrin. Temperature transponders were implanted in the air cells of embryonated and nonembryonated eggs after in ovo injection for the detection of IT at 6, 14, and 22 h after injection. The IT of embryonated eggs was significantly greater than that of nonembryonated eggs at all 3 times after the treatment period. Eggs that were injected with saline with or without supplemental carbohydrates experienced a reduction in IT when compared with control eggs whose shells were perforated without solution delivery, and the decrease in IT was associated with a delay in hatch time. Liver weight was negatively related to YSW and positively related to YFBW, and YSW was negatively related to YFBW. Although the saline and carbohydrate solution injections increased chick BW compared with noninjected controls, chick YFBW was decreased in the maltose- and sucrose-injected groups. In conclusion, the injection of 1.2 mL of saline with or without supplemental carbohydrates lowered embryonic metabolism, as reflected by a lower IT and a delay in time of hatch. However, effects of the different carbohydrate solutions on yolk absorption and tissue deposition in yolk-free embryos varied. These results suggest that lower volumes for solutions containing maltose, sucrose, or fructose should be considered for in ovo injection.

Effects of commercial in ovo injection of carbohydrates on broiler embryogenesis

The effects of in ovo injection of different carbohydrate solutions on hatchability of fertilized eggs (HF), rate of hatch, BW, body moisture, yolk sac weight, and yolk sac moisture of Ross × 708 broiler chicks, hatched from eggs laid by a 34-wk-old breeder flock, were investigated. Eggs containing live embryos were injected, using an automated multiple-egg injector, in the amnion on d 18.5 of incubation with 0.1, 0.4, 0.7, or 1.0 mL of commercial diluent or a carbohydrate dissolved in diluent. The commercial diluent containing 0.25 g/mL of one of the following carbohydrates was injected into eggs: glucose, fructose, sucrose, maltose, or dextrin. The results showed that no carbohydrate type or solution volume affected rate of hatch. Absolute and proportional BW on day of hatch were positively related to injection volume (P < 0.001). However, HF was negatively related to injection volume (P < 0.001). To realize an HF of 90%, the injection volume could not exceed 0.4 mL for fructose or sucrose and could not exceed 0.7 mL for glucose, maltose, or dextrin. Yolk-free BW was negatively related to injection volume of fructose and sucrose (P < 0.004), but was not related to injection volume of diluent, glucose, maltose, and dextrin. Conversely, absolute and proportional yolk sac weights were positively related to injection volume of fructose, sucrose, and dextrin (P < 0.01), but were also not significantly related to injection volume of diluent, glucose, and maltose. Yolk sac moisture was positively related to injection volume for all injectables, including the diluent (P < 0.03). However, body moisture and yolk-free body moisture were not related to injection type or volume. In conclusion, the use of carbohydrates added to a commercial diluent for the in ovo injection of broiler hatching eggs requires the use of appropriate volumes to promote growth and nutrient utilization without adversely affecting HF.

Influence of supplemental dietary poultry fat, phytase, and 25-hydroxycholecalciferol on the egg characteristics of commercial layers inoculated before or at the onset of lay with F-strain Mycoplasma gallisepticum

The effects of supplemental dietary poultry fat (PF), phytase (PHY), and 25-hydroxycholecalciferol (D3) on the egg characteristics of commercial layers inoculated with F-strain Mycoplasma gallisepticum (FMG) were investigated in 2 trials. Sham and FMG inoculations were administered at 12 (before lay) and 22 (onset of lay) wk and 4 dietary treatments [basal control diet (BCD); BCD with 0.75% supplemental PF; BCD with 1.50% supplemental PF; BCD with 1.50% supplemental PF, 0.013% PHY, and 0.025% D3] were initiated at 20 wk of age. Percentages of albumen, yolk, and eggshell weights; yolk:albumen ratio; yolk moisture and lipid concentrations; and eggshell weight per unit of surface area were determined at 24, 34, 44, 50, and 58 wk of age. Inoculation with FMG reduced yolk lipid concentration at wk 24 and increased yolk moisture concentration at wk 58. In birds inoculated on wk 22, percentage of yolk weight was lower in those inoculated with FMG compared with those that were sham-inoculated. Yolk:albumen ratio was lower in birds that were FMG-inoculated at 22 wk of age compared with those that were sham-inoculated at the same age or that were FMG-inoculated at 12 wk of age. Percentage of yolk weight was greater in birds inoculated at wk 22 and fed the BCD with 1.50% supplemental PF treatment compared with those inoculated at wk 22 and fed the BCD or BCD with 1.50% supplemental PF, 0.013% PHY, and 0.025% D3 treatments and compared with birds inoculated at wk 12 and fed the BCD with 0.75% supplemental PF treatment. In conclusion, inoculation with FMG before or at the onset of lay caused a decrease in yolk lipid content early in lay but an increase in yolk moisture late in lay, and FMG reduced percentage of yolk weight in birds inoculated on wk 22. Furthermore, when used in combination with added 1.50% PF in birds inoculated on wk 22, supplementary PHY and D3 prevented an increase in percentage of yolk weight that occurred in response to diets supplemented only with 1.50% PF.

Pipping muscle and liver metabolic profile changes and relationships in broiler embryos on days 15 and 19 of incubation

The relative proportions and relationships of pipping muscle and liver nutrients in broiler embryos on d 15 and 19 of incubation were determined. Ninety hatching eggs obtained from a 30-wk-old broiler breeder flock were incubated on 3 replicate tray levels (30 eggs per tray) for 19 d. On 15 and 19 d of incubation, 10 live embryos per tray level were necropsied to collect pipping muscle and liver samples. As the broiler embryo developed between d 15 and 19 of incubation, the glycogen and protein concentrations of the pipping muscle increased, whereas those of the liver decreased, and the fat concentration of the pipping muscle decreased, whereas that of the liver increased. Across d 15 and 19, pipping muscle glycogen was negatively correlated with liver fat, whereas on d 15, pipping muscle glucose was negatively correlated with liver fat, and pipping muscle glycogen was negatively correlated with liver glucose and glycogen. Pipping muscle fat was negatively correlated with liver glucose on d 15 but positively correlated with liver glycogen on d 19. In conclusion, in preparation for hatch between d 15 and 19 of incubation, weights of the liver and pipping muscle of broiler embryos increased relative to their BW. This occurred in association with the accumulation of glucose, glycogen, and protein and with the loss of fat in the pipping muscle. The carbohydrate stores in the pipping muscle were supported by the active metabolism of the liver before 19 d of incubation, which included the transfer of glucose and fatty acids to the pipping muscle via the circulation. Despite the liver's active supply of these nutrient subunits for assimilation and oxidation by the pipping muscle, there was an overall accumulation of hepatic fat between d 15 and 19 of incubation. These data suggest that the integrated changes in the energy profiles of pipping muscle and liver between 15 and 19 d of embryogenesis are integral to the broiler embryo's preparation for hatch.

Influence of supplemental dietary poultry fat, phytase, and 25-hydroxycholecalciferol on the performance of commercial layers inoculated before or at the onset of lay with F-strain Mycoplasma gallisepticum

The effects of 2 levels of supplemental dietary poultry fat (PF) and the combination of PF, phytase (PHY), and 25-hydroxycholecalciferol (D(3)) on the performance of commercial layers inoculated with F-strain Mycoplasma gallisepticum (FMG) were investigated in 2 trials. Sham and FMG inoculations were administered at 12 (before lay) and 22 (early in lay) wk and dietary treatments [basal control diet (BCD), BCD with 0.75% supplemental PF, BCD with 1.50% supplemental PF, and BCD with 1.50% supplemental PF, 0.013% PHY, and 0.025% D(3)] were initiated at 20 wk of age. Hen BW, egg weight, and egg production (EP) were determined every 4 wk between 24 and 58 wk of age. Feed consumption (FC) and feed conversion were determined in 4-wk intervals beginning on wk 25 and ending on wk 58, and total mortality and mean EP were determined over the entire 24 to 58-wk period. The addition of 0.75 and 1.50% PF increased BW at wk 48 and 58, respectively, and supplemental PF at the 1.50% level increased the BW of hens that had been inoculated (sham or FMG) on wk 22 and reduced the FC of hens inoculated on wk 12. Feed conversion was decreased in the 25 to 28- and 57 to 58-wk age periods and increased in the 45 to 48-wk age periods by an FMG inoculation. In birds inoculated at 22 wk of age, FMG increased egg weight. Although EP was reduced at wk 24 and was increased at wk 58 by FMG, total EP was not affected. In conclusion, an inoculation of FMG at either 12 or 22 wk of age can result in a relative shift in EP from the early to late stage of lay without affecting total EP, and although the BW and FC responses of hens to added dietary PF were influenced by their age and the age of inoculation, use of the supplemental combination of PHY and D(3) had no additional effect on performance when provided in conjunction with 1.50% PF.

Influence of supplemental dietary poultry fat on the digestive and reproductive organ characteristics of commercial layers inoculated before or at the onset of lay with F-strain Mycoplasma gallisepticum

Effects of F-strain Mycoplasma gallisepticum (FMG) inoculation and 1.5% supplemental dietary poultry fat (PF) on the digestive and reproductive organ characteristics of commercial layers at 58 wk of age were investigated. Sham and FMG inoculations were administered at 12 (before lay) and 22 (early in lay) wk of age, and dietary treatments (basal control diets and basal control diets with PF) were initiated at 20 wk of age. Supplemental PF increased BW and decreased isthmal length relative to total oviduct length in hens. Various oviduct segments were also affected by the type and age of inoculation, and these effects were further influenced by the use of PF. In comparison to their time-specific sham-inoculated controls, infundibulum weight relative to BW was increased when birds were inoculated with FMG at 22 wk, whereas isthmus weight relative to total oviduct weight was increased by FMG inoculation at 12 wk of age. However, PF affected infundibulum length relative to total oviduct length only in sham-inoculated birds, and PF increased magnum weight relative to total oviduct weight only in birds inoculated at 22 wk of age (sham or FMG). Furthermore, PF decreased isthmus weight relative to total oviduct weight only in birds that were sham-inoculated (12 or 22 wk). In conclusion, the inoculation of FMG at 12 or 22 wk may increase the relative contributions of the isthmus and infundibulum, respectively, to the total mass of the oviduct. In addition, PF may decrease the relative length of the isthmus and increase the relative weight of the magnum in the oviducts of birds that have been inoculated at 22 wk of age (sham or FMG). Previous studies have shown 1.5% supplemental dietary PF to influence feed consumption throughout lay and performance early in lay in hens that were inoculated with FMG at 12 wk of age. However, the current results suggest that these influences are associated with gross changes in the oviduct but not the digestive tract of layers.

Influence of supplemental dietary poultry fat on the yolk characteristics of commercial layers inoculated before or at the onset of lay with F-strain Mycoplasma gallisepticum

Effects of F-strain Mycoplasma gallisepticum (FMG) inoculation and 1.5% supplemental dietary poultry fat (PF) on the egg yolk characteristics of commercial layers at 24, 34, 44, 50, and 58 wk of age were investigated. Sham and FMG inoculations were administered at 12 and 22 wk of age and dietary treatments (basal control and basal control with 1.5% supplemental PF) were initiated at 20 wk of age. Yolk lipid concentration was reduced on wk 24 in birds that had been inoculated at 12 or 22 wk of age with FMG. The use of 1.5% supplemental PF increased percentage of yolk weight and yolk:albumen ratio across age and inoculation treatment. At 58 wk of age, concentrations of yolk palmitic acid increased and those of oleic and linolenic acid decreased when sham inoculations were given at 22 rather than at 12 wk of age. However, FMG inoculations given at 22 rather than at 12 wk increased palmitoleic acid and decreased stearic acid yolk concentrations. At 12 wk of age, FMG inoculations decreased yolk palmitoleic, oleic, and linolenic acid concentrations while causing increased yolk stearic and arachidonic acid levels when compared with sham inoculations. Furthermore, 1.5% supplemental PF decreased concentrations of palmitic and oleic acid and increased those of linoleic acid in the yolk at 58 wk of age. Despite the interaction of 1.5% supplemental PF with the prelay inoculation of FMG on early (18 to 26 wk) layer performance noted in a previous report, the effects of a prelay FMG inoculation and 1.5% supplemental PF on the egg yolk characteristics examined in the current study were independent of each other. This suggests that 1.5% supplemental PF is not effective in modulating the effects of an FMG inoculation at 12 wk of age on hen egg yolk characteristics between 24 and 58 wk of age and that the combined effects of PF supplementation and FMG inoculation on performance do not influence egg yolk characteristics.

Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts-11-strain M. gallisepticum vaccination on blood characteristics of commercial laying hens

Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in combination with subsequent time-specific F-strain M. gallisepticum (FMG) inoculations on the blood characteristics of commercial laying hens. The following 4 treatments were utilized: 1) sham vaccination at 10 wk of age, 2) vaccination of ts-11MG at 10 wk, 3) ts-11MG at 10 wk overlaid by FMG inoculation at 22 wk, and 4) ts-11MG at 10 wk overlaid by FMG at 45 wk. Parameters measured in both trials were whole blood hematocrit, plasma protein, serum cholesterol, serum triglycerides, and serum calcium. No significant age x treatment interactions and no significant age or treatment main effects were observed for any of the blood parameters investigated, except for serum calcium. At wk 22, serum calcium concentrations were increased by vaccination with ts-11MG at 10 wk, and levels were further increased when the ts-11MG vaccination at 10 wk was overlaid by an FMG inoculation at 22 wk. These results suggest that ts-11MG vaccination at 10 wk of age alone or combined with F-strain inoculum overlays at either 22 or 45 wk may be used without any consequential effects on hematocrit or the lipid and protein levels in the blood of commercial layers. Because elevations in serum calcium were not associated with changes in hen performance, as reported in a previous companion article, it is further suggested that prelay ts-11MG vaccination before FMG inoculation overlays during lay may provide adequate protection against field strain M. gallisepticum infections while being innocuous to layer performance.

Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts-11-strain M. gallisepticum vaccination on digestive and reproductive organ characteristics of commercial egg-laying hens

Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in conjunction with F-strain M. gallisepticum (FMG) inoculation overlays at 2 different age periods during lay on the digestive and reproductive organ characteristics of commercial egg-laying hens. In each trial, the following 4 treatments were utilized: sham vaccination at 10 wk of age, ts-11MG vaccination at 10 wk of age, ts-11MG at 10 wk of age overlaid by FMG inoculation at 22 wk of age, and ts-11MG at 10 wk of age overlaid by FMG at 45 wk of age. Necropsies were performed at the end of both trials (58 wk of age), using 2 birds from each of 4 replicate units per treatment, to observe treatment effects on the following parameters: liver weight, liver lipid and moisture concentrations, incidence of fatty liver hemorrhagic syndrome, ovary weight, number of mature ovarian follicles, and the total and segmental weights, lengths, and histologies of the oviduct and small intestine. Treatments affected only vaginal length as a percentage of total oviduct length. Vaginas were relatively longer in hens that had only been vaccinated with ts-11MG at 10 wk in comparison to all the other treatment groups, including controls. Except for relative vaginal length, the digestive and reproductive organs of layers were not influenced by the ts-11MG and FMG treatment regimens imposed in this study. These results confirm that when coupled with FMG inoculations during lay, prelay ts-11MG vaccinations may be a practical substitute for prelay FMG inoculations for providing continual protection against field-strain M. gallisepticum infections in layers.

Influence of supplemental dietary poultry fat on the performance of commercial layers inoculated before or at the onset of lay with F-strain Mycoplasma gallisepticum

The effects of F-strain Mycoplasma gallisepticum (FMG) inoculation and 1.5% supplemental dietary poultry fat (PF) on the performance of commercial layers between 20 and 58 wk of age were investigated. Sham and FMG inoculations were administered at 12 (before lay) and 22 (early in lay) wk and dietary treatments (basal control diets and basal control diets with 1.5% supplemental PF) were initiated at 20 wk of age. Mortality at wk 47 and 53 was greatest in birds inoculated with FMG at 22 wk. Feed consumption from 20 to 23 and from 52 to 55 wk of age was greater in birds that were inoculated with FMG (12 or 22 wk). However, feed consumption decreased in birds that were inoculated at 12 wk (sham or FMG) when 1.5% supplemental PF was added to the diet. Percentage of total egg production (EP) between 22 and 58 wk of age was highest in hens that were inoculated with FMG at 22 wk. Furthermore, weekly EP increased at wk 27 and 58 and decreased at wk 47 after birds had been inoculated with FMG (12 or 22 wk), and increased at 22 wk and decreased at 54 wk when inoculations (sham or FMG) were given at 22 wk. Egg weight was increased at wk 29, 31, 39, 40, 42, 44, 53, and 58 in birds that were inoculated with FMG (12 or 22 wk); however, there were no coherent treatment effects on eggshell quality. An FMG inoculation at 22 wk may promote total EP through 58 wk, whereas the inoculation of commercial layers with FMG (12 or 22 wk) may increase subsequent feed consumption during the early and late stages of EP and increase egg weight throughout lay. However, the supplementation of hen diets with 1.5% PF beginning at 20 wk of age may reduce subsequent feed consumption throughout lay in birds having experienced a prelay (12 wk) inoculation.

Effects of prelay 6/85-strain Mycoplasma gallisepticum inoculation alone or in conjunction with the inoculation of F-strain Mycoplasma gallisepticum during lay on the blood characteristics of commercial egg-laying hens

The effects of 6/85-strain Mycoplasma gallisepticum (6/85MG) inoculation alone or in conjunction with F-strain M. gallisepticum (FMG) overlays and their timing on the blood characteristics of commercial egg-laying hens were investigated. Control birds received sham inoculations at 10 wk of age. Birds in a second treatment group were inoculated with 6/85MG at 10 wk of age, those in a third treatment group were inoculated with 6/85MG at 10 wk followed by an overlay inoculation of FMG at 22 wk, and those in a fourth treatment group were inoculated with 6/85MG at 10 wk followed by an overlay inoculation of FMG at 45 wk. Parameters investigated at 24, 32, 43, and 47 wk were hematocrit, plasma total protein, and serum calcium, triglycerides, and cholesterol. No significant treatment effects were noted for hematocrit, serum triglycerides, or serum cholesterol. However, at wk 32, plasma protein was greater in birds that received 6/85MG at 10 wk or 6/85MG at 10 wk and FMG at 22 wk in comparison to controls. Also, at wk 47, serum calcium concentration was greater in birds that received 6/85MG at 10 wk and FMG at 45 wk compared with controls and those that received 6/85MG at 10 wk and FMG at 22 wk. These results suggest that the prelay inoculation of pullets with 6/85MG may subsequently elevate plasma protein, and in conjunction with an FMG overlay at 45 wk, may increase serum calcium concentrations in laying hens.

Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts11-strain Mycoplasma gallisepticum inoculation on performance characteristics of commercial laying hens

Mycoplasma bacteria are virtually ubiquitous in layer chicken flocks, and Mycoplasma gallisepticum is the species of greatest concern to commercial egg producers. Live M. gallisepticum vaccines were initially approved by the USDA for use in commercial layers in 1988 to help control M. gallisepticum outbreaks. In the present study, 2 trials were conducted to determine the effects of 2 currently available live Mycoplasma vaccines (the ts11-and F-strains) when used together. The following 4 inoculation treatments were used: 1) sham inoculation at 10 wk of age, 2) ts11 at 10 wk, 3) ts11 at 10 wk overlaid by the F-strain at 22 wk, and 4) ts11 at 10 wk overlaid by the F-strain at 45 wk. In each trial, at various ages between 18 and 57 wk of age, hen mortality; BW; egg weight; egg production; eggshell breaking strength; incidences of egg blood spots, egg meat spots, and eggshell pimpling; and eggshell weight per unit of surface area were assessed. The effects of inoculation treatment on egg weight at 27, 37, and 38 wk were inconsistent and variable. Eggshell pimpling and egg blood spot incidences at 56 wk were highest in eggs belonging to the ts11 at 10 wk/F-strain at 45 wk group. Despite increases in pimpling and blood spot incidences very late in production because of the ts11 at 10 wk/F-strain at 45 wk treatment, performance in layers was not adversely affected by a 10-wk ts11 inoculation alone or in conjunction with subsequent overlay inoculations of the F-strain during lay. It is therefore suggested that the 10-wk inoculation of commercial layers with ts11 may reduce the negative impacts of a prelay F-strain inoculation on performance, as reported in earlier studies, while providing protection against subsequent field strain M. gallisepticum infections. Furthermore, the ts11- and F-strain M. gallisepticum treatment combinations may overcome some of the inadequacies that prelay ts11- or F-strain M. gallisepticum vaccines may have when given independently.