Effects of in ovo vaccination time on broiler performance parameters under field conditions

Hatchery performance is often evaluated based on descriptors such as hatchability, 7-d mortality, and cost. In addition to these descriptors, it is useful to include in this analysis aspects of chick quality through post-hatch performance. Realizing the bird's complete genetic potential necessitates meeting various criteria, with effective support for the chick's immune system being among the pivotal factors. To be effective, in ovo vaccination systems must deliver the vaccines to specific sites in the egg, a circumstance that directly depends on when the injection is made. We examined production data to evaluate the impact of in ovo vaccination time on performance parameters of male Ross308AP chicks. A comprehensive survey was conducted examining records from 3,722 broiler flocks produced and raised by the same company under standard nutrition and management conditions. The selected data specifically pertained to flocks that underwent slaughter between 41 and 45 d. In our analysis, 4 different linear models were built, one for each response variable: mean weight (MW), body weight gain (BWG), corrected feeding conversion rate (cFCR), and total mortality (TM). The linear models used in the analyses included as main predictor the timing of in ovo vaccination (440, 444, 448, 452, 456, 458, and 460 h of incubation), and as additional predictors: age of the breeding flock (26-35, 36-55 and 56-66 wks old), slaughter age, identity of the hatchery, and the season at which the data was collected. Our results showed that the timing of in ovo vaccination significantly affected BWG and cFCR, with procedures performed at 460 h of incubation showing the best outcomes. Breeding flock age affected all response variables, with older breeding flocks delivering increased MW, BWG and TM, and middle-aged flocks increased cFCR. Increasing slaughter age reduced BWG while MW, cFCR and TM were all increased. These data emphasize the benefits of performing in ovo vaccination as close as possible to 460 h of incubation to extract the best BWG and cFCR from Ross308AP male broiler.

Productive performance, breast growth and digestive system development in European quail subjected to post-hatch fasting for different periods

This study assessed the effect of different periods of post-hatch fasting on animal performance and breast and digestive system growth in European quail. Quail chicks were distributed in a completely randomized design, with four fasting periods (0, 24, 36, and 48 hs) and four replications of 40 birds per treatment. In 1 to 14-day-old chicks, weight gain decreased with increasing fasting time. Compensatory gain was observed from 15 days of age onward. Fasted quail had a lower length and relative weight of the digestive system than fed animals for up to 14 days. Histologically, the duodenal villus height was significantly lower in 3-day-old quail fasted for 36 hs than in those fasted for 48 hs, but this effect was not observed at 7 days. Scanning electron microscopy showed no differences in the small intestinal mucosa between fasted and fed birds at 3 days of age. Post-hatch fasting reduced the relative weight of the breast in quail aged 1 to 14 days but did not affect type IIa and IIb fiber diameter at 35 days. On the basis of these results, it is recommended that European quail raised for meat should not be fasted for more than 48 hs post-hatch.

Performance traits and selected blood constituents of broiler chicks as influenced by early access to feed post-hatch

The present study aimed to investigate the effect of early access to feed and water post-hatch on broiler chicks' performance. One hundred and twenty chicks were transferred from the hatchery to the rearing house and randomly divided into two groups. The first group: chicks were immediately access to feed and water (F-time 0). The second group: was held without feed and water for 24 h (F-time 24). Then, feed and water were provided ad-libitum, for both groups until 35 days of age. Results indicated that F-time 0 increased body weight and body weight gain throughout the experimental period. It increased feed intake during all experimental periods except from (22-28 days). Additionally, the F-time 0 enhanced the European production efficiency factor index. The F-time 24, increased red blood cells (RBCs) count, hemoglobin (HGB), and packed cell volume (PCV) percentage after 24 h. However, the F-time 0 had a higher RBCs count, HGB, and PCV at 35 days of age. F-time 24 increased total plasma protein, albumin, cholesterol, and triglycerides, after 24 h. In conclusion, early access to feed and water post-hatch enhances broiler chicks' performance and productivity and increases producers' revenue.

Antimicrobial Use in On-Farm Hatching Systems vs. Traditional Hatching Systems: A Case Study

On-farm hatching is a relatively new method in the broiler industry, in which fertilized broiler eggs are transported to the farms at the stage of 17-19 days of incubation. Once hatched, the broiler chicks have direct access to feed and water. Previous studies have shown on-farm hatching to increase animal welfare and intestinal development. However, no studies have yet aimed to quantify and compare the antimicrobial use in on-farm hatched flocks with that of traditionally hatched flocks. In this study, information on antimicrobial use (AMU) was collected from 211 Belgian conventional broiler farms, including data from 2244 traditionally hatched flocks and 227 on-farm (NestBorn) hatched flocks. On-farm hatched flocks had significantly (p < 0.001) more antimicrobial-free flocks (n = 109, 48.01%) compared to traditional flocks (n = 271, 12.08%) and a 44% lower (p < 0.01) treatment incidence (TI) at flock level (TI 8.40 vs. TI 15.13). Overall, the farms using traditional hatching had 5.6 times (95% CI 3.6-8.7) higher odds to use antimicrobials than the farms using on-farm hatching. Treated on-farm hatched flocks received three times less lincomycin-spectinomycin (linco-spectin) and less (routine) treatments at the start of the production round. However, both traditional and on-farm flocks experienced outbreaks later in the production round. These results show that on-farm hatching can contribute to the reduction in antimicrobial use in conventional broiler production.

Effects of access to feed, water, and a competitive exclusion product in the hatcher on some immune traits and gut development in broiler chickens

This study evaluated the effect of access to feed, water, and the competitive exclusion (CE) product Broilact®, administered in the hatcher, on broiler performance, caecal microbiota development, organ development, intestinal morphology, serum levels of IgY and vaccine-induced antibody responses.In total, 250 chicks were hatched in a HatchCare^TM hatcher and divided into four groups, given access to feed, water and the CE product sprayed on the chicks (CEs); access to feed, water, and the CE product in water (CEw); access to feed and water (Cpos); or no access to feed and water (Cneg) in the hatcher. At the research facility, 10 chicks per hatching treatment were euthanized for organ measurements. The remaining 200 chicks were randomly distributed to 20 pens. On d 11, all birds were vaccinated against avian pneumovirus (APV). Three focal birds per pen were blood-sampled weekly for quantification of IgY and serum antibodies to APV. On d 11 and 32, two birds per replicate pen were euthanised for organ measurements and sample collection. Feed intake and body weight were recorded weekly.Delayed access to feed and water reduced weight gain and feed intake early in life. At the end of the study, no differences in body weight remained.There were some early effects on organs, with depressed intestinal development and higher relative gizzard weight for the Cneg group at placement. No treatment effects on the immune traits measured were detected. The relative abundance of seven bacterial genera differed between treatment groups at d 11 of age. The results suggested that chickens are capable of compensating for 40 h feed and water deprival post-hatch. Provision of Broilact® did not have any persistent performance-enhancing properties, although different outcomes under rearing conditions closer to commercial production cannot be ruled out.

Effect of L-arginine and L-Lysine HCl ratio on growth performance and ileum morphology of native chickens aged 2-14 weeks

Background and Aim:

Micronutrients such as essential amino acids in chicken feed must be balanced to promote optimal development. The balance of the amino acids arginine and lysine in chicken feed is particularly important. This study aimed to examine the effect of the ratio of L-arginine to L-Lysine HCl on growth performance and ileum morphology of native chickens aged 2-14 weeks-old.

Materials and Methods:

One hundred and eighty 2-week-old native chickens which initial weight 78.10±4.97 g were classified into six treatments and five repetitions using a completely randomized design.

Treatments were based on the ratio of arginine to lysine in the feed:

T1 (0.50% L-arginine: 0.85% L-lysine HCl); T2 (0.75% L-arginine: 0.85% L-lysine HCl); T3 (1.00% L-arginine: 0.85% L-lysine HCl); T4 (0.50% L-arginine: 1.00% L-lysine HCl); T5 (0.75% L-arginine: 1.00% L-lysine HCl); and T6 (1.00% L-arginine: 1.00% L-lysine HCl).

Results:

Groups T3 and T6 had the highest feed consumption (42.06±0.29 and 42.78±0.72 g/bird/day, respectively), while Group T6 had the highest body weight and body weight gain rate (1505.60±103.20 kg/bird and 16.99±1.24 g/bird/day, respectively). Groups T3 and T6 also had the highest carcass weight (916.16±46.99 and 947.18±62.32 g/bird, respectively). The best feed conversion was seen for Groups T3, T5, and T6 (2.55±0.14, 2.50±0.20, and 2.53±0.19, respectively). For ileum morphometry, the highest villus height occurred in Groups T2, T3, T5, and T6 (962.80±23.31, 982.80±10.03, 972.80±18.99, and 989.80±10.69 μm, respectively); and Group T6 had the highest crypt depth and villus width (340.80±11.52 and 302.00±4.00 μm, respectively). Statistical analysis indicated significant differences among the treatment groups for all variables examined (p<0.05).

Conclusion:

The highest ratio of arginine-lysine was associated with the largest increase in native chicken feed consumption, body weight gain, feed conversion, and carcass weight, as well as villus height and width, and crypt depth in the ileum. Overall, an arginine-lysine ratio of 0.8-1.20 promoted optimal growth of native chickens aged 2-14 weeks. In the future, it is important to increase the arginine-lysine ratio with low feed protein levels in native chickens.

Induction of gut leakage in young broiler chickens fed a diet with low rye inclusion

The aim of the present study was to assess the absence of a non-starch polysaccharide (NSP) enzyme in a broiler diet containing a low level (10%) of rye inclusion. Two experimental groups with 40 Ross broilers each, were fed a diet containing 10% rye. One group was supplemented with a NSP enzyme, and the other was not supplemented with the enzyme to increase intestinal viscosity. The birds were fed the respective diets for 14 or 28 days. Intestinal sections were submitted to morphological, morphometric and mRNA-level gene expression analyses. To assess gut leakage, 150 min before euthanasia, broilers had no access to feed and received an oral gavage with fluorescein isothiocyanate-labelled dextran (FITC-d). Serum levels of FITC-d, D-lactate, tight-junction-associated protein 1 (TJAP1), citrulline and ovotransferrin were determined. A significant increase in FITC-d levels was observed in the 14-day-old birds fed the non-supplemented rye diet, and no other serum markers were affected. These birds presented a decreased villus height/crypt depth (VH:CD) ratio and an increased degree of damage in the jejunum. The ileum VH:CD increased, and the goblet cell number decreased in 28-day-old birds fed the non-supplemented rye diet. When broilers were fed the non-supplemented rye diet, the mRNA expression of the tight-junction zona occludens 1 (ZO1) was significantly decreased in the jejunum of 14-day-old broilers, whereas a significant decrease in jejunum mRNA expression of ZO2 and mucin-2 (MUC2) was observed in the jejunum of 28-day-old broilers. In contrast, a significant increase in the mRNA expression of ZO2 was observed in the ileum from 28-day-old broilers fed the non-supplemented rye diet. In conclusion, a 10% rye diet causes intestinal stress in young broiler chickens when the feed is not supplemented with a NSP enzyme. This study may be applied as experimental model of mild gut leakage of broiler chickens.

Early Nutrition with Different Diets Composition versus Fasting on Immunity-Related Gene Expression and Histomorphology of Digestive and Lymphoid Organs of Layer-Type Chicks

Simple Summary

With the continuous improvement in the progress of poultry industry, a better understanding of the avian immune system is necessary. A prolonged holding period (36–72 h), along with a delay in access to feed and/or water post-hatching, has a negative influence on performance, intestinal histomorphology, and the immune system development of chicks. Therefore, the present study aimed to investigate the effect of early feeding with different diet composition or delayed feeding during the first 72 h of chick’s life on the expression of immunity-related genes and histomorphology of digestive and lymphoid organs of layer-type chicks. Early nutrition post-hatching had no negative effect on the development of the lymphoid and digestive organs in chicks. Histomorphological examination revealed an increase in cortex and cortex:medulla of thymus and bursa in the early fed groups compared to the fasted ones, with resultant impacts on the primary lymphoid organs. Higher germinal center areas and white pulp of the spleen were recorded in the early fed chicks, implying augmented proliferation and maturation of B cells in the secondary lymphoid organs. In the liver, a strong positive reaction to Best’s carmine stain in the early fed groups, indicating that the liver of these chicks had numerous glycogen granules in the cytoplasm of hepatocytes. The expression levels of splenic-immunity related genes were up-regulated in most of the early fed chicks at 14 day of age. Our findings suggested that early feeding post-hatch can modify the splenic-immunity related genes and modulate the histomorphology of the digestive (liver and proventriculus) and lymphoid organ in layer-type chicks during the early life post-hatching.

Abstract

Early feeding post-hatching (EFPH) can impact the immune response and modify the immunity-related gene expression. Therefore, we aimed to examine the effects of EFPH with different diets composition versus fasting during the first 72 h of chick’s life on the histomorphological structures of the liver, proventriculus, central and peripheral lymphoid organs, and immunity-related genes in layer-type chicks during the brooding period. A total of 400 chicks were randomly allotted into 4 groups with 4 replicates each. The experimental groups during the first 72 h of life were: feed and water deprivation (control, T1), feeding a starter layer diet (20% CP and 11.84 MJ/kg ME, T2), feeding a starter layer diet contained 3% molasses in its composition (20% CP and 11.81 MJ/kg ME; T3), and feeding a starter broiler diet (23% CP and 12.68 MJ/kg ME, T4). After the first 72 h of chick’s life, all chicks were fed ad libitum the T2 diet. EFPH had no negative effect on the development of the lymphoid or digestive organs in chicks. Greater relative weights of the spleen and bursa of Fabricius (p < 0.05) were observed in the early fed chicks compared to control at day 14 of age. Histomorphological examination revealed an increase (p < 0.05) in thymus cortex and cortex:medulla in the T3 and T4 groups compared to the fasted ones at day 28 of age. Pelicae height, follicular width, cortex, and cortex:medulla of bursa were improved (p < 0.01) in the fed groups compared to fasted chicks, with resultant influences on the primary lymphoid organs. Compared to control, higher germinal center areas and white pulp of the spleen (p < 0.05) were recorded in the early fed chicks, implying augmented proliferation and maturation of B cells in the secondary lymphoid organs. In the liver, a strong positive reaction to Best’s carmine stain in the early fed groups, indicating that the liver of these chicks had numerous glycogen granules or greater glycogen density in the cytoplasm of hepatocytes. There was a significant enhancement in the proventriculus mucosal and gland thickness, as well as fold height (p < 0.05) in the early fed chicks. The expression levels of splenic Toll-like receptor 2, interleukin 4, tumor necrosis factor α, and interferon gamma were up-regulated (p < 0.01) in most of the early fed chicks (T2, T3, and T4) compared to fasted ones at 14 day of age. In conclusion, EFPH could modify the splenic-immunity related genes and modulate the histomorphology of the digestive (liver and proventriculus) and lymphoid organs in layer-type chicks during the brooding period.

Effects of Betaine Supplementation on Live Performance, Selected Blood Parameters, and Expression of Water Channel and Stress-Related mRNA Transcripts of Delayed Placement Broiler Chicks

This study examined the effect of supplemental betaine on live performance, selected blood parameters, and gene expression of water channel proteins (Aquaporins, AQP) of broiler chicks delayed in placement for 48 h post-hatch. In total, 540 newly-hatched male broiler chicks were obtained from a local hatchery and were randomly allotted to one of five treatments with nine replicates per treatment (12 chicks per replicate). Chicks were either placed immediately, control; held for 48 h post-hatch with no access to feed or water, Holdnull; held for 48 h with free access to drinking water only, HoldW; held for 48 h with free access to drinking water supplemented with 1 ml per L of betaine solution (40% betaine), HoldB1; or held for 48 h with free access to drinking water supplemented with 2 ml per L of betaine solution (40% betaine), HoldB2 group. The results showed that post-hatch holding for 48 h depressed feed intake and body weight gain during the entire 15 d study period with no beneficial effect of supplemental betaine. Chicks in the HoldB2 group had elevated serum glucose, triglycerides, and aspartate aminotransferase 48 h post-hatch. Early water deprivation directly affected the brain proopiomelanocortin (POMC) and hepatic glucocorticoid receptors (GR) expression and induced significant changes in various aquaporins (AQP1, AQP2, AQP4, and AQP9). In conclusion, betaine supplementation to chicks held for 48 h post-hatch resulted in some changes in blood biochemical indices with no effects on performance during the first 15 days of life. The results suggest that betaine supplementation could ameliorate the stressful effects of water deprivation on POMC and GR expression and maintain cellular osmosis through interactions with variable aquaporins expression, particularly the AQP1 and AQP2. Further investigations are required to investigate the molecular mechanisms underlying the selective regulatory expression of different aquaporins in relation to betaine supplementation.

Effects of hatching system on the welfare of broiler chickens in early and later life

Broiler chicks usually hatch in the hatchery without access to feed and water until placement at the farm. This can affect their health and welfare negatively. Therefore, alternative strategies have been developed, for instance providing chicks with early nutrition in the hatchery or hatching eggs directly on-farm. However, information on the physical and mental welfare of chicks hatched in these systems compared to conventionally hatched chicks is limited. The aim of this study was to investigate the effects of alternative hatching systems on the welfare of broiler chickens in early and later life. A system comparison was performed with chickens that hatched conventionally in a hatchery (HH), in a system which provided light, feed, and water in a hatcher (hatchery-fed, HF), or on-farm (on-farm hatched, OH, where feed and water were available and transport of day-old chicks from the hatchery to the farm was not necessary). Chickens were reared in 3 batches, in 12 floor pens per batch (approximately 1,155 animals per pen), with a total of 12 replicates per treatment. Animal-based welfare indicators were assessed following standard protocols: plumage cleanliness, footpad dermatitis (FPD), hock burn, skin lesions (all at day 21 and 35 of age), and gait score (day 35). Furthermore, a set of behavioral tests was carried out: novel environment (day 1 and 21), tonic immobility, novel object, and avoidance distance test (day 4 and 35). Plumage cleanliness, hock burn, and skin lesions were affected by age but not by hatching system, with older broilers scoring worse than younger ones (P < 0.05). An effect of hatching system was only found for FPD, with the highest prevalence in HH chickens, followed by HF and OH chickens (P < 0.05). All responses measured in the behavioral tests were affected by age but not by hatching system. In later life, chickens were significantly less fearful than during the first days of life. The results indicate that conventionally hatched chickens scored significantly worse for FPD, whereas, in general, hatching system seemed to have minor effects on other broiler welfare indicators.

Effect of posthatch feed and water access time on residual yolk and broiler live performance

This study investigated the effect of feed and water access time on yolk sac utilization and subsequent broiler live performance. Hatching eggs were collected from commercial flocks of Ross 308 breeders at 35 and 39 wk of age in experiments 1 and 2, respectively. Chicks already out of their shells that still had some dampness on their down were removed, recorded, feather-sexed, and weighed at 488 h of incubation in both experiments. Chicks were weighed individually and received feed and water at 2 (immediate feed; IF), 8, 12, 16, 20, 24, 28, and 32 h after hatching (488 h) in experiments 1 and 2 (IF) and at 24, 26, 28, 32, 36, and 40 h after hatching in experiment 2.

The residual yolk sac weight was determined at 32 and 40 h after hatching (day 0) in all groups in experiments 1 and 2, respectively. Feed consumption and BW were recorded at 7, 14, 21, and 35 d and at the same age relative to placement on feed and water at the end of the growing period. Mortality was recorded twice daily in both experiments.

Feed and water access time did not influence yolk sac utilization in either experiment (P > 0.05). The IF group exhibited a higher (P < 0.05) BW than those that received feed at or after 28 h at 35 d in both experiments. There was a significant increase in feed consumption in the IF group compared with the groups with access to feed and water after 24 h at 35 d in experiment 2 (P < 0.05), with a similar trend in experiment 1 (P > 0.05). There were no significant differences in the feed conversion ratio (FCR) or mortality at 35 d of age, but the IF group tended to have a poorer FCR than the other groups in both experiments. When the total feed and water times were equalized among all groups, irrespective of the deprivation duration, there were no significant differences among the groups in the BW, feed consumption, the FCR, or mortality in both experiments.

It can be concluded that feed and water deprivation for 28 h or longer after hatching (≥28 h) negatively affects the final BW but tends to improve the FCR at 35 d of age compared with chicks that receive feed immediately (2 h after hatching). When the feeding period was equalized in all groups, feed and water deprivation up to 40 h under optimum conditions had no detrimental effect on final live performance. These results suggest that the total feeding period is more critical for broiler performance than the time of posthatch access to feed and water.

Effects of First Feed Administration on Small Intestinal Development and Plasma Hormones in Broiler Chicks

Simple Summary

In this study, the effects of first feed administration on intestinal morphology, barrier function, and plasma hormones in broilers during the initial 168 h posthatch. Results revealed that early feeding posthatch had a positive effect on small intestinal growth by increasing weight and improving intestinal morphology and barrier function. In other words, early feeding promoted intestinal development, which could be very meaningful for commercial broiler production.

Abstract

(1) Background: Under practical conditions, newly hatched chicks were usually withheld feed and water for 48 to 72 h. It was shown that early feeding after hatch promoted gastrointestinal development of broiler chicks. However, the mechanism of early feeding affecting intestinal development in chicks needs further research. The present study was conducted to investigate the effects of first feed administration on intestinal morphology, barrier function, and plasma hormones in broilers during the initial 168 h posthatch. (2) Methods: A total of 720 one-day-old chicks (newborn chick, Lingnan Yellow) were placed 2 h after hatch and randomly assigned to three treatments: Group A (feed immediately after placement), Group B (fasting for 24 h after placement), and Group C (fasting for 48 h after placement). The trial lasted for 168 h and water ad libitum all the time. Sampling was performed at 0, 24, 48, 72, 120, and 168 h. (3) Results: Higher (p < 0.05) absolute weight and relative weight of the small intestine were observed in Group A. Moreover, the villus height, crypt depth, and ratio of the jejunum and ileum were significantly higher (p < 0.05) in Groups A and B than those in Group C. Microvilli of the duodenum were closely packed in Group A but sparse and disorganized in Groups B and C. The expression levels of mRNA and protein of tight junction genes (occludin and claudin-1) were upregulated (p < 0.05) in Group A. The levels of gastrin and insulin in plasma were decreased (p < 0.05) significantly in the Groups B and C. However, chicks in Groups B and C had higher (p < 0.05) plasma glucagon levels at 24 and 48 h after placement. (4) Conclusions: These results suggested that early feeding posthatch had a positive effect on small intestinal growth increasing weight and improving intestinal morphology and barrier function.

Delayed access to feed affects broiler small intestinal morphology and goblet cell ontogeny

Broilers are often deprived of feed and water for up to 48 h after hatch. This delayed access to feed (DAF) can inhibit small intestine development. The objective of this study was to determine the effects of DAF on small intestinal morphology, mRNA abundance of the goblet cell marker Muc2 and absorptive cell marker PepT1, and the distribution of goblet cells in young broilers. Cobb 500 chicks, hatching within a 12-h window, were randomly allocated into 3 groups: control with no feed delay (ND), 24-h feed delay (DAF24), and 36-h feed delay (DAF36). Morphology, gene expression, and in situ hybridization analyses were conducted on the duodenum, jejunum, and ileum at 0, 24, 36, 72, 120, and 168 h after hatch. Statistical analysis was performed using a t test for ND and DAF24 at 24 h. A 2-way ANOVA and Tukey's HSD test (P < 0.05) were used for ND, DAF24, and DAF36 from 36 h. At 24 to 36 h, DAF decreased the ratio of villus height/crypt depth (VH/CD) in the duodenum but increased VH/CD in the ileum due to changes in CD, whereas at 72 h, DAF decreased VH/CD due to a decrease in VH. The mRNA abundance of PepT1 was upregulated, while Muc2 mRNA was downregulated in DAF chicks. Cells expressing Muc2 mRNA were present along the villi and in the crypts. The ratio of the number of goblet cells found in the upper half to the lower half of the villus was greater in DAF chicks than in ND chicks, suggesting that DAF affected the appearance of new goblet cells. The number of Muc2 mRNA-expressing cells in the crypt, however, was generally not affected by DAF. In conclusion, DAF transiently affected small intestinal morphology, upregulated PepT1 mRNA, downregulated Muc2 mRNA, and changed the distribution of goblet cells in the villi. By 168 h, however, these parameters were not different between ND, DAF24, and DAF36 chicks.

Risk factors for poor health and performance in European broiler production systems

BACKGROUND

Conventional broilers are currently one of the most efficient protein converters. Although decades of progress in genetic selection and feed formulation have lead to high standards of efficient broiler production, still a lot of variability is found between farms and between successive flocks. The aim of this study was to investigate risk- and/or protective factors for poor health and performance in conventional broiler-farms in Europe by developing eight multivariable linear mixed models. Three different models were used to investigate mortality (overall, first week, after first week), three models for performance variables (growth, feed conversion, European production index) and two models were related to slaughterhouse data (i.e. dead on arrival and condemnation rate).

RESULTS

Several factors related to management and housing were significantly associated with health and performance of broilers. The following factors were associated with increased mortality: floor quality, neonatal septicemia, ventilation type and other professional activities of the farmer. The factors associated with performance were chick sex, coccidiosis infections, necrotic enteritis, dysbacteriosis, light intensity adaptations, ventilation type, comparing daily flock results with previous flock results by farmer, daily check of feed and water system and type of feed. For dead on arrival three risk factors were identified i.e. daily growth, type of light adaptation and type of drinkers system. For condemnation rate seven risk factors were found, i.e. type of drinking system, daily growth, feed withdrawal time, type of ventilation, house size, septicemia after seven days and type of feed.

CONCLUSIONS

These results imply that a multifactorial approach is required with adaptations involving both improvements in management, housing, health programs and an increasing level of professionalism of the farmer in order to improve broiler performance and health.

Effects of on-farm and traditional hatching on welfare, health, and performance of broiler chickens

In on-farm hatching systems, eggs that have been incubated for 18 D are transported to the broiler farm. After hatching around day 21, the chicks have immediate access to feed and water. By contrast, traditionally hatched chicks are in early life exposed to dust and pathogens in the hatcher, handling procedures, and transport and remain without feed and water until they have arrived on the farm 1 to 3 D after hatching. We compared welfare and performance of on-farm hatched (OH) and traditionally hatched control (C) Ross 308 broiler chickens from day 0 to 40, housed under semicommercial conditions. The experiment included 3 production cycles in 4 rooms, with each room containing 1 OH and 1 C pen with 1,150 chickens in each pen. Per cycle, C and OH chicks were from the same batch of eggs of 1 parent stock flock. Day-old chick quality was worse for OH than C chickens (hock and navel score; P < 0.05). On-farm hatched chickens were heavier than C chickens until day 21 of age (P < 0.05). Total mortality was significantly lower in OH compared with C pens (P < 0.05). A tendency for lower footpad dermatitis scores was found in OH pens compared with C pens (P < 0.10), probably because of the dryer litter in OH than C pens (P < 0.05). No differences between treatments were found in gait, hock burn, cleanliness, and injury scores, and no or only minor, short lasting differences were found in pathology and intestinal histology. In conclusion, the present study showed that on-farm hatching may be beneficial for broiler welfare, as it reduced total mortality and resulted in dryer litter which is known to be beneficial for reducing footpad dermatitis.

Mineral supplementation: effects on bone integrity and intestinal morphometry of broiler chickens challenged with Eimeria sp

The objective of this study was to evaluate the effect of supplementation of organic minerals on the productive performance and bone quality of broilers from 1 to 21 days of age and the intestinal health in situations of enteric challenge from 21 to 28 days of age. In a completely randomized design, with two treatments composed for minerals as sulfate and Carbo-Amino-Phospho-Chelate (CAPC), a total of 900 male broiler chicks were allocated to nine replicates and 18 experimental units with 50 birds each. 640 birds at 21 days of age were transferred to experimental cages and distributed in a completely randomized design, in factorial 2 × 2 (minerals as sulfate and CAPC × with and without enteric challenge), obtaining 4 treatments with 16 replicates and 10 birds each. In the same day of change, the group of challenged broilers received a commercial vaccine for coccidiosis that covers the Eimeria sp. At 7 days, the supplementation with CAPC minerals resulted in higher (p<0.05) weight gain and better feed conversion in relation to the inorganic source. The deposition of minerals evaluated in the tibia of broilers was not influenced (p>0.05) by the source of minerals, with the exception of Cu and Mn, whose deposition was greater (p<0.05) in the bones of poultries supplemented with inorganic source of minerals. There was higher (p<0.05) length and width of the villi and increase in the ratio villus: crypt in response to the intestinal spoliation with CAPC supplementation when compared to the inorganic source.

Influence of fibre and betaine on development of the gastrointestinal tract of broilers between hatch and 14 d of age

An experiment was designed to determine the influence of fibre and betaine on the development of the intestine, liver and pancreas of broilers from hatch to 14 d of age. A total of 250-day-old Cobb 500 male broilers were allocated to 16 cages with 15 broilers each. Treatments were arranged in a 2 × 4 factorial design, consisting of 2 feed formulations (low and high fibre diets) and 4 levels of betaine (0, 1, 3 or 5 kg/t). At hatch, 10 birds in total were euthanised, and samples of the liver, pancreas, yolk sac and intestine were collected for reference of the analysed parameters before the start of the trial. On d 4, 9 and 14, 5 birds per cage (10 birds per treatment) were selected, euthanised and treated as the same as the birds at hatch. Villus height and width and crypt depth were determined on the duodenum samples, and absorptive area was calculated. The number of enterocytes in mitosis at the villus was determined by a positive reaction to antibody for Ki67 protein, and fused villus was evaluated visually. The relative weight of the yolk sac reduced (P < 0.05) as birds aged while the intestine and liver reached a maximum (P < 0.05) at around d 4 and the pancreas at d 9. Birds fed the high fibre diet had greater feed intake, lower relative weight of the pancreas and higher villus (P < 0.05) than birds fed the low fibre diet. Villus width increased (P < 0.05) at 4 d of age, and this was associated with fused villus. Betaine inclusion reduced (P < 0.05) villus width, increased (P < 0.05) villus size and absorptive area, and reduced (P < 0.05) the number of enterocytes with positive reaction for the antibody Ki-67. Betaine inclusion reduced the width and increased the absorptive area and the villus height of the duodenum of birds up to 14 d of age. The higher fibre diet increased feed intake and villus height, yet reduced pancreas relative weight, while not affecting body weight gain. This response was possibly due to a dilution effect of the fibre, reducing nutrient absorption and consequently stimulating villus growth to improve absorption rates.

A 'meta-analysis' of effects of post-hatch food and water deprivation on development, performance and welfare of chickens

A 'meta-analysis' was performed to determine effects of post-hatch food and water deprivation (PHFWD) on chicken development, performance and welfare (including health). Two types of meta-analysis were performed on peer-reviewed scientific publications: a quantitative 'meta-analysis' (MA) and a qualitative analysis (QA). Previously reported effects of PHFWD were quantified in the MA, for variables related to performance, mortality and relative yolk sac weight. The QA counted the number of studies reporting (non-)significant effects when five or more records were available in the data set (i.e. relative heart, liver and pancreas weight; plasma T3, T4 and glucose concentrations; relative duodenum, jejunum and ileum weight; duodenum, jejunum and ileum length; and villus height and crypt depth in duodenum, jejunum and ileum). MA results indicated that 24 hours of PHFWD (i.e. ≥12-36 hours) or more resulted in significantly lower body weights compared to early-fed chickens up to six weeks of age. Body weights and food intake were more reduced as durations of PHFWD (24, 48, 72, ≥84 hours) increased. Feed conversion rate increased in chickens up to 21 and 42 days of age after ≥84 hours PHFWD in comparison with chickens fed earlier. Total mortality at day 42 was higher in chickens after 48 hours PHFWD compared to early fed chickens or chickens after 24 hours PHFWD. First week mortality was higher in chickens after ≥84 hours PHFWD than in early fed chickens. The MA for relative yolk sac weight was inconclusive for PHFWD. The QA for plasma T3, T4 and glucose concentrations indicated mainly short-term decreases in T3 and glucose in PHFWD chickens compared to early fed chickens, and no effects of PHFWD on T4 concentrations. Relative weights of liver, pancreas and heart were lower after PHFWD, but only in the first week of life. A retarded development of gut segments (duodenum, jejunum and ileum) was found in the first week of life, measured as shorter, lower relative weight, and lower villus height and crypt depth. It is concluded that 48 hours (≥36-60 hours) PHFWD leads to lower body weights and higher total mortality in chickens up to six weeks of age, the latter suggesting compromised chicken welfare, but effects of PHFWD on organ development and physiological status appear to be mainly short-term.

In ovo nutrient supplementation improves the performance and intestinal morphology in early feed deprived egg type chickens

The effect of in ovo feeding (IOF) in ameliorating the adverse effects of feed deprivation (FD) was studied in egg type chickens (White leghorn). The experimental design was a 3 × 3 factorial design with three treatments (in ovo, sham and un-injected control) and three types of feeding (immediate fed or fasted for 24 h and 36 h) as factors. Response criteria were embryonic weight, digestive organ development, growth performance, intestinal and villi morphology. Embryonic weight at 20 d (% of pre incubated egg) in IOF group was significantly higher compared to un-injected control group. IOF chicks had higher body weight (BW), proventriculus weight, duodenal villi length (VL) and villi width (VW) at 24 and 36 h post hatch (PH) than the sham control and un-injected control chicks. Immediately fed and 24 h FD chicks had significantly higher BW than 36 h FD chicks, while organ weight was higher in immediately fed chicks compared to FD chicks. The IOF and 24 h FD chicks had higher digestive organ weight, BW and VL than the un-injected and immediately fed chicks. IOF and 36 h FD chicks had comparable performances with un-injected control and immediately fed chicks. It is concluded that in ovo supplemented chicks can withstand early post-hatch feed deprivation and had improved PH performance.

Effects of time of initiation of feeding after hatching and diet composition on performance, carcass characteristics, digestive tract development and immune responses of broilers

This study was conducted to evaluate the effects of time of initiation of feeding after hatching and influence of diet composition on growth performance, carcass characteristics, digestive tract development and immune responses of broilers. A total of straight-run 420 Ross 308 broiler chicks were randomly allotted to six treatments with five replicates of 14 chicks each. The dietary treatments consisted of feeding a maize-soybean meal diet immediately posthatching until 14 days of age (Control), fasting for 24 or 48 h posthatching, feeding maize for 24–48 h posthatching, and feeding a maize gluten-dextrose pre-starter diet for 5 days posthatching. The study lasted from 0 to 42 days of age. For the entire 42-day period, chicks fasted or fed maize for 48 h posthatching or those fed the maize gluten-dextrose diet for 5 days posthatching had lower (P &lt; 0.05) feed intake and lower (P &lt; 0.05) weight gain compared with the Control. However, birds fasted or those fed maize for 24 or 48 h posthatching had similar (P &gt; 0.05) feed intake and weight gain as the Control. The duodenal villus height and villus height:crypt depth ratio were lower (P &lt; 0.05) and the duodenal crypt depth was higher (P &lt; 0.05) in birds fasted for 48 h posthatching compared with the Control. Conversely, birds fasted for 48 h posthatching had higher (P &lt; 0.05) jejunal villus height and villus height:crypt depth ratio and lower (P &lt; 0.05) jejunal crypt depth compared with the Control. The antibody titres against Newcastle disease was lower (P &lt; 0.05) for the groups other than the Control, whereas the antibody titres against Avian Influenza virus was lower (P &lt; 0.05) in birds fasted for 48 h posthatching and in those fed maize for 48 h posthatching compared with the Control. Also, birds fed maize for 24 h posthatching had lower (P &lt; 0.05) antibody titres against sheep red blood cells compared with the other treatments. These results indicated that feeding a maize-soybean meal starter diet immediately after hatch has a beneficial effect on growth performance and immune response of broilers and improves morphological development of the intestine.

Sunflower cake with or without enzymatic complex for broiler chickens feeding

Objective

This study was to evaluate the sunflower cake and enzymatic complex fed to broilers from 22 to 42 d of age.

Methods

In a completely randomized design, a total of 850 birds were allotted in a 2×5 factorial scheme (with and without enzymatic complex) and five inclusion levels (0%, 5%, 10%, 15%, 20%) of sunflower cake. There were 5 replications and 17 birds in each experimental unit. Data from performance, carcass yield and intestinal morphology were evaluated.

Results

Feed intake, weight gain, final weight and feed:gain ratio linearly worsened as sunflower cake increased. For weight gain, final weight and feed:gain ratio, the birds whose diets contained levels of 15% and 20% of sunflower cake showed worse values (p<0.05) than the birds fed the control diet. When fed the enzymatic complex, birds improved (p<0.05) crypt depth and villus:crypt ratio in the jejunum. As inclusion levels of sunflower cake increased, villus depth and villus:crypt ratio in duodenum, jejunum and ileum linearly reduced and the crypt depth linearly increased. Carcass yield linearly reduced as sunflower cake increased.

Conclusion

Based on performance, sunflower cake can be used up to 10% in broilers feeding from 21 to 42 days of age.

Effects of feed access after hatch and inclusion of fish oil and medium chain fatty acids in a pre-starter diet on broiler chicken growth performance and humoral immunity

Delayed feed and water access is known to impair growth performance of day old broiler chickens. Although effects of feed access on growth performance and immune function of broilers have been examined before, effects of dietary composition and its potential interaction with feed access are hardly investigated. This experiment aimed to determine whether moment of first feed and water access after hatch and pre-starter composition (0 to 7 days) affect growth rate and humoral immune function in broiler chickens. Direct fed chickens received feed and water directly after placement in the grow-out facility, whilst delayed fed chickens only after 48 h. Direct and delayed fed chickens received a control pre-starter diet, or a diet containing medium chain fatty acids (MCFA) or fish oil. At 21 days, chickens were immunized by injection of sheep red blood cells. The mortality rate depended on an interaction between feed access and pre-starter composition (P=0.014). Chickens with direct feed access fed the control pre-starter diet had a higher risk for mortality than chickens with delayed feed access fed the control pre-starter diet (16.4% v. 4.2%) whereas the other treatment groups were in-between. BW gain and feed intake till 25 days in direct fed chickens were higher compared with delayed fed chickens, whilst gain to feed ratio was lower. Within the direct fed chickens, the control pre-starter diet resulted in the highest BW at 28 days and the MCFA pre-starter diet the lowest (Δ=2.4%), whereas this was opposite for delayed fed chickens (Δ=3.0%; P=0.033). Provision of MCFA resulted in a 4.6% higher BW gain and a higher gain to feed ratio compared with other pre-starter diets, but only during the period it was provided (2 to 7 days). Minor treatment effects were found for humoral immune response by measuring immunoglobulins, agglutination titers, interferon gamma (IFN- γ ), and complement activity. Concluding, current inclusion levels of fish oil (5 g/kg) and MCFA (30 g/kg) in the pre-starter diet appear to have limited (carryover) effects on growth and development, as well as on humoral immune function.

Stress Levels, Mortality, Intestinal Morphometry and Histomorphology of Chabro Broiler Birds Subjected to Varying Degrees of Post Hatch Delay in Feeding

BACKGROUND AND OBJECTIVE

Kashmir is a part of Jammu and Kashmir State of India where a large chunk of day old chicks are procured from outside the state and these chicks are transported across a distance of hundreds of kilometers over a period of several days. The long distance transport without any access to feed not only subjects the birds to early life stress but also affects their gut morphological development. Therefore, a study was conducted to evaluate the effect of delayed feeding on stress levels, mortality, intestinal morphometry and histomorphology of chabro broiler chicken.

MATERIALS AND METHODS

A total of 400 day old chabro chicks were randomly divided into 5 groups, each group comprising of four replicates of 20 birds. Chicks allotted to group-1 (G 1) were offered feed at hatchery itself whereas feeding in groups G 2, G 3, G 4 and G 5 were initiated at the farm after the delay of 12, 24, 48 and 72 h, respectively.

RESULTS

The results revealed that the heterophil count showed a steady increase from G 1-G 5 and significantly (p<0.05) higher count was found in G 3, G 4 and G 5 compared to G 1. However, the lymphocyte count showed a steady decrease as delay in feeding increased. H:L ratio followed a regular increase from G 1-G 5 and was significantly (p<0.05) higher in G 3, G 4 and G 5 compared to G 1. An overall mortality of 13% was recorded during the trial and all of it occurred during first 2 weeks. The highest overall mortality of 22.50±3.23% was recorded in group G 5 followed by 17.50±6.61% in G 4. The villus height of duodenum and jejunum was significantly (p<0.05) higher in G 2, G 3, G 4 and G 5 as compared to G 1. Crypt depth and muscular is thickness of duodenum was significantly (p>0.05) lower in G 4 and G 5 compared to G 1.

CONCLUSION

The duration of post hatch feeding delay gradually increased the stress level and mortality of birds and also decreased the length of different segments of small intestine in birds. No adverse effect on histomorphology was observed at the end of trial. Feeding at hatchery itself or feeding during transportation of birds would be a viable strategy to overcome the negative effects of delayed feeding in chicken.

Effects of starter diet supplementation with arginine on broiler production performance and on small intestine morphometry

The effects of starter diet (days 1 to 21) supplemented with arginine (Arg) on the production performance and duodenum and jejunum mucosa morphometry of broilers were studied. Male Cobb broiler chickens (990) were randomly assigned to one of five treatments in a complete random design. Measurements of 33 chicks per treatment were made in six repetitions. The treatments consisted of a basal diet with 1.390% digestible Arg (no supplementation) and four dietary levels (1.490%, 1.590%, 1.690%, and 1.790%), providing a relationship with lysine of 1.103; 1.183; 1.262; 1.341 and 1.421%, respectively. From the age of 22 days on, all birds received conventional grower diet. The data were submitted to regression analysis by polynomial decomposition of the degrees of freedom in relation to the levels of Arg. The Arg supplementation increased (P<0.05) the live weight and the feed conversion ratio without increasing the feed intake of the birds. However, no effect was observed (P>0.05) in the growth phase (days 22 to 42) in the absence of the Arg supplementation. The supplementation of Arg over of NRC recommendation during the starter phase may be necessary for the expression of the maximal weight gain potential in birds. No effect (P<0.05) of Arg dietary supplementation was observed either on small intestine weight and length at any age. However, the duodenum villus:crypt ratio increased and the crypt depth decreased in the first week in response to increasing dietary Arg. It is concluded that broiler Arg dietary supplementation in the starter diet improved production performance and small intestine morphometry, especially in the first week.

Inoculation of newly hatched broiler chicks with two Brazilian isolates of Salmonella Heidelberg strains with different virulence gene profiles, antimicrobial resistance, and pulsed field gel electrophoresis patterns to intestinal changes evaluation

Salmonella Heidelberg is one of the 3 most frequently isolated serovars from human Salmonella cases in Canada, and the fourth most commonly reported Salmonella serovar in human foodborne disease cases in the United States. Since 1962, Salmonella Heidelberg has been isolated and reported in poultry and poultry products in Brazil. The poultry industry has focused efforts on reducing salmonellae incidence in live production in an effort to reduce Salmonella in the processing plant. A better understanding of the initial infection in chicks could provide approaches to control Salmonella contamination. The objective of the present study was to evaluate 2 Salmonella Heidelberg strains that differed in the presence of virulence genes invA, agfA, and lpfA; antimicrobial resistance profiles; and epidemiologic profiles on aspects of pathogenicity and intestinal morphology. Newly hatched broiler chicks were inoculated with 2 strains (SH23 and SH35) of Salmonella Heidelberg and cecal morphometry, histopathology, electron microscopy, and bacterial counts in the liver and cecum were assessed. The SH23 and SH35 strains resulted in different changes in villi height and crypt depth and inflammatory cell infiltration in the cecum. The SH35 group had higher liver and cecum bacterial cell counts when compared with SH23 strains.

Factors affecting intestinal health in poultry

The gastrointestinal (GI) tract has the most extensive exposed surface in the body and is constantly exposed to a wide variety of potentially harmful substances. The GI tract acts as a selective barrier between the tissues of the bird and its luminal environment. This barrier is composed of physical, chemical, immunological, and microbiological components. A wide range of factors associated with diet and infectious disease agents can negatively affect the delicate balance among the components of the chicken gut and, as a result, affect health status and production performance of birds in commercial poultry operations. Phasing out of antibiotic growth promoters from poultry diets in Europe and recent moves toward reduction or removal of these compounds in other parts of the world including North America will likely change the microbial profile of the GI tract environment in commercial poultry. This paper reviews the GI tract from developmental, immunological, and microbial standpoints and then discusses factors that can affect health status of this system. Necrotic enteritis and coccidiosis and their interactions, and possible consequences of antibiotic growth promoter removal from poultry diets with respect to these diseases, are discussed in more detail.