Contrasting the effects of phytase and pure myo-inositol on the performance, digestibility, blood and egg yolk inositol levels and digestion physiology of laying hens

ABSRACT1. An experiment was designed to compare the effects of supplementing laying hen diets with phytase and myo-inositol (inositol).2. Five diets were formulated: high balanced protein (HBP - 840 mg of Dlys/hen/day), HBP with inositol (HBP+I - 0.16%), reduced balance protein (RBP - 672 mg of Dlys/hen/day), RBP with inositol (RBP+I - 0.16%) and RBP with phytase (RBP+P - 3000 FTU/kg).3. Laying hen production, inositol concentrations, digestive tract morphology, amino acid digestibility and intestinal inositol transporters transcript abundance were evaluated. Data were analysed with a one-way ANOVA in SAS 9.4. Contrasts were used to assess the effect of protein, inositol, phytase and phytase vs. inositol. Differences were accepted when P ≤ 0.05.4. No effect on hen-day egg production or feed efficiency was found. However, feed intake and the incidence of abnormally shaped eggs were 0.77 g/h/d and 0.17% higher, respectively, in inositol treatments. Inositol decreased egg specific gravity from 1.088 to 1.0865.5. Inositol concentration in egg yolk was similar among HBP+I, RBP+I and RBP+P, and higher than for the HBP and RBP diet groups. Both gizzard and ileal digesta were enriched in inositol in all supplemented treatments, and phytase supplementation decreased the level of IP5 and IP6 in the gizzard and ileum. Generally, neither phytase or inositol affected amino acid digestibility.6. Inositol increased transcript abundance of alkaline phosphatase in the ileum, while phytase upregulated duodenal alkaline phosphatase and SMIT1, jejunal SMIT2 and reduced ileal HMIT and SMIT1 abundance.7. In conclusion, no effect of phytase or inositol was found for laying hen production performance or amino acid digestibility, but egg quality was reduced by inositol supplementation. Inositol concentration in egg yolk was similar among supplemented treatments.

Development of a Coccidiosis Disease Challenge Model Using a Commercially Available Live Oocyst Vaccine

With growing cross-disciplinary collaboration among researchers, it is increasingly important to record detailed methodology to prevent the repetition of preliminary experiments. The purpose of this paper is to explain the development of a coccidiosis challenge model for the investigation of dietary interventions to coccidiosis in broiler chickens. The objectives are to select a dose of mixed species coccidial vaccine and evaluate the suitability (ability to produce a consistent, marked change) of selected response variables important to nutritional studies at different times postinfection (PI). Coccivac-B and Coccivac-B52 (Merck Animal Health) were evaluated as the source of coccidia in three trials. Trials 1 and 2 were randomized complete block designs with four doses (0, 10, 20, or 30 times (×) label dose) of Coccivac-B administered to 12 replicate cages of six birds by repeater pipette (Trial 1) or gavaging needle (Trial 2). Trial 3 used a completely randomized design with 0× or 30× label dose of Coccivac-B52 administered by gavaging needle to six replicate cages of six birds. Birds were gavaged at 15 days of age, and response criteria were evaluated 7 days PI in all trials and again at 10 days PI in Trials 1 and 2. All means are reported in order of increasing coccidia dose with significance accepted at P ≤ 0.05. Broiler performance was not affected by coccidia in Trials 1 or 3 but grew poorer with increasing dose from 0 to 7 days PI in Trial 2 (body weight gain, 465, 421, 388, 365 g; feed to gain, 1.37, 1.47, 1.52, 1.58). As coccidia dose increased, nitrogen corrected apparent metabolizable energy decreased (Trial 1, 3387, 3318, 3267, 3170 kcal kg^-1; Trial 2, 3358, 2535, 2422, 2309 kcal kg^-1; Trial 3, not measured), while relative weight, length, and content for intestinal sections increased (Trials 1through 3). Gross lesion (duodenum, jejunum/ileum, ceca) and oocyst count scores (jejunum/ileum, ceca) increased with dose; however, gross scoring often suggested infection in unchallenged birds, a finding unsupported by oocyst count scores. At 7 days PI there was no correlation between midgut gross lesion score and midgut oocyst count score (r = 0.06, P = 0.705), but cecal scores were weakly correlated (r = 0.55, P < 0.001). Administering coccidia via repeater pipette (Trial 1) resulted in respiratory distress in some birds, while use of the gavaging needle (Trials 2 and 3) successfully induced intestinal damage in chickens without resulting in coccidia related mortality. Thirty times the label dose at 7 days PI resulted in the greatest number of response variables that produced a consistent, marked change. Therefore, consideration should be given to these conditions when designing future coccidiosis challenge models using vaccines as a source of coccidia.

The influence of indigestible protein on the performance and meat quality of broilers vaccinated for coccidiosis

High dietary protein and the use of poorly digested protein sources have been suggested to negatively impact broiler health, possibly because of protein fermentation in the distal intestinal tract. The effect of dietary protein levels with low or high indigestible protein fractions (LIP or HIP) on male and female broiler performance were evaluated. The trial was completely randomized with a 2 × 3 × 2 factorial arrangement, where gender, dietary protein levels (24, 26, and 28%), and dietary protein digestible fractions were the main factors. Ross 308 male (1944) and female (2232) were allocated to 72 pens with 54 males or 62 females per pen. Six grower diets 24-LIP, 24-HIP, 26-LIP, 26-HIP, 28-LIP, and 28-HIP were fed from 0 to 32 D of age. Birds were vaccinated with Coccivac-B52 on day 5, and feed intake and BW were recorded on 0, 12, 22, and 32 D. On day 32, 24 birds per treatment were processed for meat yield. Males were heavier than females at all post-hatch ages and the LIP birds were heavier than their HIP counterparts on 32 D. On day 22, birds fed 24 and 26% CP were heavier than those fed 28% CP. Birds fed the 28-LIP diet consumed less total feed than their 24 and 26-LIP equivalents. Birds fed 24% CP had the highest total feed to gain ratio, whereas LIP fed birds had a lower total feed to gain than those fed HIP diets. LIP diets resulted in higher total mortality than the HIP diets. Carcass yield was higher for females than males, increased with CP level, and was lower in HIP than LIP birds. An interaction between CP level and protein digestibility resulted in the 26 and 28-LIP having higher breast yield than all other diets. In conclusion, broiler growth performance and meat yield were affected by dietary indigestible protein alone or in combination with gender and dietary CP level.

The impact of beak tissue sloughing and beak shape variation on the behavior and welfare of infrared beak-treated layer pullets and hens

This research examined how infrared beak treatment (IRBT), sloughing of the treated beak tissue, and the variations in beak shape that can occur post-IRBT impact the welfare and mortality of Lohmann LSL-Lite (LW) and Lohmann Brown (LB) pullets and hens. Two experiments were conducted and birds for both experiments were treated on the day of hatch. IRBT equipment settings were adjusted to create 4 specific beak shapes: shovel (SHV), step (STP), standard (STAN), and an untreated sham control (C). Experiment 1 pullets (n = 80 per strain) were reared in bioassay cages from 1 to 29 D of age (4 replicates per treatment). Data collected included time and presence of beak sloughing, pecking force, behavioral expression, and mortality. Experiment 2 pullets (n = 320 per strain) were reared in floor pens from 1 D to 18 wk of age (2 replicates per treatment) and then conventional cages from 18 to 60 wk of age (6 replicates per treatment). Data collected for Experiment 2 included behavioral expression, feather cover, comb damage, and mortality. Data were analyzed using PROC MIXED (SAS® 9.4) with Tukey's test to separate means. Differences were significant when P ≤ 0.05. IRBT and sloughing had no effect on pecking force or mortality throughout rearing. The variations in post-IRBT beak shape had minor effects on behavior. During rearing, STAN pullets were more active than C pullets but STP and STAN pullets performed less exploratory pecking. During the laying period, SHV and STP hens preened more than C hens. The IRBT treatments, regardless of beak shape, reduced feather loss, comb damage, and cannibalism-related mortality during the laying period. Overall, the results indicate that LW and LB pullets and hens can cope with the change in beak shape that occurs with IRBT, and that welfare is not negatively impacted if some variation in beak shape occurs.

The effect of beak tissue sloughing and post-treatment beak shape on the productivity of infrared beak-treated layer pullets and hens

Infrared beak treatment (IRBT) results in a change in beak shape; however, it is unclear what effect variations in post-treatment beak shape have on young pullets. Additionally, the impact of sloughing of the treated beak tissue is not fully understood. Two experiments were conducted to determine the effects of beak tissue sloughing and post-treatment beak shape on the productivity of infrared beak-treated Lohmann Brown (LB) and Lohmann LSL-Lite (LW) pullets and hens. Birds were treated on day of hatch and IRBT equipment settings were adjusted to create 4 specific beak shapes: shovel (SHV), step (STP), standard (STAN), and an untreated sham control (C). Experiment 1 pullets (n = 160) were housed in cages from 1 to 29 d of age and had access to water through chick founts or 360° nipple drinkers (2 replicate cages per treatment). Data collected included body weight (BW), feed intake (FI), feed efficiency (FE), and water disappearance (WD). Experiment 2 pullets (n = 640) were housed in floor pens from 1 d to 18 wk of age (2 replicate pens per treatment) then conventional cages during the laying period (6 replicate cages per treatment). Data collected included BW, FI, egg production, and egg quality. Data were analyzed using PROC MIXED (SAS® 9.4) and differences were significant when P ≤ 0.05. During early life, the IRBT treatments and sloughing had minor effects on FI, FE, and BW. At 4 wk of age, STAN pullets were lighter than C pullets; however, differences were no longer apparent after this age. Pullets with STP or STAN beak shapes had lower WD than C pullets when allowed access to water via nipple drinkers but this did not result in reduced growth. Throughout the laying period, SHV hens laid more saleable eggs than C hens, with no other effects on production. Overall, variations in beak shape and sloughing of the beak tissue had minimal impacts on the productivity of LW and LB pullets and hens.

In vivo digestion characteristics of protein sources fed to broilers

The rate and extent of protein digestion are relevant to broiler performance and health, but information is lacking on the rate of digestion and the characteristics of the undigested fraction for common protein feed ingredients. Therefore, this study evaluated the digestion kinetics and the distal ileum (DI) digesta protein characteristics of protein meals fed to broiler chickens. Using a completely randomized design, 360 male broilers at 14 D of age were assigned to 60 battery cages and fed semi-purified diets composed of wheat starch (N-free) or wheat starch with either corn distillers dried grains with solubles (CDDGS), corn gluten meal, meat and bone meal, soybean meal, fish meal (FM), porcine meal (PCM), canola meal, blood meal (BM), or feather meal. At day 21, the protein digestion kinetics and total and soluble protein of the DI content were determined. Differences were considered significant when P ≤ 0.05. Protein source affected the extent of amino acid (AA) and CP digestibility at the DI. The results demonstrated differences in digesta mean retention time (MRT) and the rate of digestion of AA and CP among protein sources. FM had the shortest MRT of 46 min, whereas CDDGS had the longest at 142 min. Both FM and PCM had the highest digestion rates for most of the AA evaluated among the protein sources, whereas CDDGS had the lowest. In turn, the total and soluble CP in the distal ileal contents ranged from 54 to 1466 mg and 6 to 347 mg, respectively. In conclusion, dietary protein source influences the amount and solubility of the undigested protein in the DI and the digestion kinetics of AA and CP along the small intestine of broilers. These parameters may contribute to the effects of protein source on muscle deposition and could influence the impact protein sources may have on gut health through protein fermentation.

The effects of stocking density on turkey tom performance and environment to 16 weeks of age

Stocking density (SD) of turkey toms (n = 2,868 Nicholas Select) was evaluated in 2 16-wk trials. Poults were randomly allocated to 1 of 8 independently ventilated rooms (6.71 × 10.06 m) for each trial, to reach a final target SD of 30, 40, 50, or 60 kg/m2. Air quality was monitored (carbon dioxide and ammonia) throughout the trial, and ventilation was adjusted to balance these parameters across all rooms. Within each trial, body weight and feed consumption were recorded (0, 4, 8, 12, and 16 wk of age). Body weight gain and mortality-corrected feed-to-gain ratio (F: Gm) were calculated for each 4-wk interval. Uniformity was assessed at 12 and 16 wk of age (20 birds per replicate). Mortality and culled birds were recorded daily and necropsied to determine cause of death or illness. Room temperature was recorded hourly, and litter moisture and temperature (trial 2) were evaluated weekly from 12 to 16 wk. A 1-way ANOVA was performed to evaluate the effects of SD on room temperature. Regression analyses were performed to determine the relationship between SD and all other measured variables (linear, Proc Reg; quadratic, Proc RSReg in SAS 9.4). Differences were considered significant when P ≤ 0.05. Body weight decreased as SD increased at 12 (quadratic) and 16 wk (linear). Body weight gain decreased in the last 4 wk (12 to 16, linear) and over the course of the trial (0 to 12, quadratic; 0 to 16, linear) as SD increased. Feed consumption demonstrated a linear relationship with increasing SD, increasing from week 4 to 8 and decreasing from week 12 to 16. The F: Gm ratio increased linearly with increasing SD for all time periods beginning at week 4. Flock uniformity and total percent mortality were unaffected by SD. Litter moisture demonstrated a quadratic effect and litter temperature increased (quadratic) as SD increased. Overall, increasing SD negatively impacted aspects of bird performance, including body weight, body weight gain, and feed efficiency. Feed consumption was negatively impacted later in production (week 12 to 16). Finally, overall mortality and uniformity were not affected.

The impact of dark exposure on broiler feeding behavior and weight of gastrointestinal tract segments and contents

Ross 308 broilers were observed at 2 ages to quantify how duration of darkness affects behavior and alters the gastrointestinal tract (GIT, segment and content weights) over 24 h. Four treatments provided 1 (1D), 4 (4D), 7 (7D), or 10 (10D) h of darkness. Birds (n = 4000) were housed in 8 rooms with 8 pens per room (2 replications per treatment and 4 replications per gender per room). The GIT data were collected on day 27 to 28 (6 males per treatment, euthanized at 2 h intervals for 24 h) and expressed as a percentage of body weight. Data were analyzed as a completely randomized design, with treatment nested within room. Production data were analyzed as a 4 (dark) x 2 (gender) factorial arrangement and GIT data as a 4 (dark) x 12 (time) factorial arrangement. Regression analyses established relationships between darkness and dependent variables. At 31 d, regression analyses showed no effect on body weight. The highest feed consumption was observed under 4D. Mortality was lowest under 10D. Birds on 10D were the most feed efficient and had the heaviest crops. Crop content interacted with time of day, with peaks prior to dark under 4D, 7D, and 10D. Empty gizzard weight increased linearly as dark increased (P < .01). Behavior was examined as a 4 (dark) x 2 (age) x 2 (gender) factorial arrangement of treatments. Five birds per gender per room were focally observed for 24 h. Dark data were examined using regression analyses and an analysis of variance assessed age and gender data. As dark increased, feeding bout frequency increased and total time spent at the feeder decreased linearly (P = 0.01 and P < .01, respectively). As birds aged, feeding frequency decreased and feed bout length increased. Males visited the feeder more frequently. Birds anticipated dark periods >4 h and increased feeding activity prior to dark. Broilers adapt their feeding behavior in response to dark exposure, which alters GIT segment and content weight and likely feed passage rate.

MHC variability in heritage breeds of chickens

The chicken Major Histocompatibility Complex (MHC) is very strongly associated with disease resistance and thus is a very important region of the chicken genome. Historically, MHC (B locus) has been identified by the use of serology with haplotype specific alloantisera. These antisera can be difficult to produce and frequently cross-react with multiple haplotypes and hence their application is generally limited to inbred and MHC-defined lines. As a consequence, very little information about MHC variability in heritage chicken breeds is available. DNA-based methods are now available for examining MHC variability in these previously uncharacterized populations. A high density SNP panel consisting of 101 SNP that span a 230,000 bp region of the chicken MHC was used to examine MHC variability in 17 heritage populations of chickens from five universities from Canada and the United States. The breeds included 6 heritage broiler lines, 3 Barred Plymouth Rock, 2 New Hampshire and one each of Rhode Island Red, Light Sussex, White Leghorn, Dark Brown Leghorn, and 2 synthetic lines. These heritage breeds contained from one to 11 haplotypes per line. A total of 52 unique MHC haplotypes were found with only 10 of them identical to serologically defined haplotypes. Furthermore, nine MHC recombinants with their respective parental haplotypes were identified. This survey confirms the value of these non-commercially utilized lines in maintaining genetic diversity. The identification of multiple MHC haplotypes and novel MHC recombinants indicates that diversity is being generated and maintained within these heritage populations.

Effects of wheat distillers dried grains with solubles with or without protease and β-mannanase on the performance of turkey hen poults

Expansion in bioethanol production has resulted in distillers dried grains with solubles (DDGS) being readily available as a major protein source in the poultry industry. Two experiments were conducted to investigate effects of wheat DDGS (wDDGS) and enzyme on nutrient digestibility and performance of turkey hen poults (7 to 21 d). Two starter diets (0 or 30% wDDGS) were formulated to meet or exceed the nutrient requirements for Hybrid Converter female turkeys. These diets were then mixed in different proportions to obtain 2 additional wDDGS inclusion levels (10 and 20%). In Experiment 1, 0 and 30% wDDGS diets were each subdivided into 3 portions and supplemented with no enzyme (E-), protease (P+; 0.125 g/kg) or β-mannanase (M+; 0.5 g/kg). A total of 144, 7-day-old poults were randomly distributed in groups of 4 in 6 replicate cages per treatment. There were no significant main effects or interactions on feed intake from 7 to 21 d. However, a positive (P<0.05) effect of 30% wDDGS was shown for weight gain and gain:feed. A significant interaction on nitrogen retention (NR) was found between enzymes and wDDGS level. There were significant main effects and interactions on the AME of the diets. The AME was higher (P<0.05) for 30% compared to 0% wDDGS. Supplementation of P+ decreased (P<0.05) AME for 0% diets as compared to 30% diets and vice versa for M+. In Experiment 2, 7-day-old poults (4 birds per 6 replications per treatment) were fed 4 levels of wDDGS (0, 10, 20, and 30%) with no enzyme. A linear (P<0.01) response was found for gain:feed with 30% wDDGS having a better response. Quadratic (P<0.01) responses were also found for NR and AME; both were highest for 10% wDDGS diets. In summary, no beneficial effects of P+ or M+ were demonstrated in diets containing 30% wDDGS. Wheat DDGS is a valuable energy source and as high as 30% can be incorporated in turkey hen poults (7 to 21 d) diets.

Evaluation of inclusion level of wheat distillers dried grains with solubles with and without protease or β-mannanase on performance and water intake of turkey hens

It is becoming a common practice to use higher levels of wheat distillers dried grains with solubles (wDDGS) in poultry diets. The objective of this study was to determine the effects of level of inclusion of wDDGS with or without enzyme (E-, i.e., wDDGSE-) supplementation on performance and water consumption of turkey hens (0 to 72 d). Two diets (0 or 30% wDDGS) were formulated to meet the nutrient requirements of Hybrid Converter turkeys. Diets (0 or 30% wDDGS; starter, grower, and finisher) were then blended to obtain a different level of inclusion (15%) of wDDGS. The 30% wDDGS diet was divided into 3 fractions and 2 fractions supplemented with either protease (P+, i.e., wDDGSP+; 0.126 g/kg) or β-mannanase (M+, i.e., wDDGSM+; 0.05 g/kg). All 5 diets were fed ad libitum as mash. The 700 0-d turkey hens were randomly allocated into groups of 35 birds per replicate with 4 replicate floor pens per treatment, in a completely randomized design. Water consumption per pen was recorded beginning at 7 d. There was no effect of dietary treatment on feed intake. BW of turkey hens (52 d; grower) was significantly higher for 30% wDDGSP+ as compared to 0% wDDGSE- or 15% wDDGSE- diets; but was not different from 30% wDDGSE- or 30% wDDGSM+ diets. FCR (P < 0.01; 28 to 52 d), and total FCR (P < 0.05; 0 to 72 d) was significantly improved for birds fed 15 or 30% wDDGS regardless of enzyme treatment compared to 0% wDDGSE-. Water intake (WI, in mL per bird per day) tended to be higher (P = 0.08) between 7 and 28 d for 30% wDDGSP+ diets compared to other treatments. Similarly, WI of birds fed 30% wDDGSP+ was higher (P < 0.05; 28 to 52 and 52 to 72 d) and total WI (P = 0.07; 7 to 72 d) tended to be higher than other treatments. This study is the first to report the impact of wDDGS on WI. As high as 30% wDDGS can be substituted in turkey hen diets. No effect of P+ or M+ at the inclusion level tested was found on performance.

The effect of toe trimming on behavior, mobility, toe length and other indicators of welfare in tom turkeys

Society is increasingly concerned about the welfare of animals kept for food production, for this reason, invasive procedures such as toe trimming in turkeys must be studied to assess the corresponding welfare implications and to ensure such procedures are acceptable for continued use. To this end, research was conducted to evaluate the welfare effects of toe trimming on toms raised to 140 d. The study used 306 Hybrid Converter toms, half of which were toe trimmed using a Microwave Claw Processor (MCP) which group are denoted T, and half of which were sham treated but not trimmed, which group are denoted NT. Turkey behavior was observed on d 1, 3, 5, and 133. Toe cross sections were taken every second day for 14 d after treatment and were used to histologically examine the healing process. Toe length, gait score, and bird stance were assessed on d 55, 84, 119, and 139. For the first 5 d after treatment, T birds demonstrated less active behaviors such as feeding, standing, walking and running (P ≤ 0.05), indicative of pain with the effect diminishing with age. At d 133, T turkeys stood more and walked less than NT birds (P ≤ 0.05). Gait score and bird stance were not affected by treatment. Trimmed toes were on average 91.9% of the length of NT toes and toe length was more variable (P ≤ 0.05) as a result of the trimming process. Histological examination indicated T toes had complete epithelium closure over the healthy tissue by d 8 and were fully healed by d 14. Although bird mobility and stance were unaffected by treatment, turkey behavior both early and late in the production cycle were suggestive of pain and balance effects; both indicators of reduced welfare as a result of toe trimming.

The effects of extrusion of wheat distillers dried grains with solubles with or without an enzyme cocktail on performance of turkey hen poults

Two experiments were conducted to determine if extrusion (EX) or enzymes (E) could overcome the restrictions (e.g., high fiber) of feeding wheat distillers dried grain with solubles (wDDGS) and improve its nutritional value for feeding turkeys. Two starter diets with either 0 or 30% wDDGS were formulated to meet or exceed the nutrient requirements of the Hybrid Converter female turkeys. The 30% wDDGS diet was substituted with either non-extruded (EX-) or extruded (EX+) wDDGS to produce three basal diets [0% wDDGS (EX-) or 30% wDDGS (EX-/EX+)]. Diets were blended to obtain 15% wDDGS. In the respective treatments, only wDDGS was extruded (temperature; 118°C, retention; 15 sec, total moisture; 25% and pressure 33 bar). The respective experimental diets were supplemented with/without an enzyme cocktail (E; 0.5 g/kg). Test diets were fed from 7-21 d in a completely randomized design. In Experiment 1, a total of 210 turkey hen poults were fed diets containing 0, 15, or 30% wDDGS (EX-) with or without enzyme (E+/E-). Body weight (BW) and feed intake (FI) were significantly higher for 0% wDDGSE-. Nitrogen retention (NR) and apparent metabolizable energy (AME) for the 30% wDDGSE- was significantly higher than other treatments at 21 d. The results indicated significant main effects of E and an interaction between wDDGS level and E. In Experiment 2, 280 turkey hen poults were fed 8 diets [15/30% wDDGS (E+/E-), (EX-/EX+)]. The level of wDDGS had a significant effect on BW, FI and gain:feed; 15% inclusion was superior to 30%. There were significant 2- and 3-way interactions for AME and NR at 21 d due to differences in enzyme response with 15 or 30% wDDGS inclusion and/or extrusion of wDDGS. As high as 15% wDDGS can be incorporated in turkey hen diets. There were no beneficial effects of EX or E on poult performance.

Cloacal and surface temperatures of tom turkeys exposed to different rearing temperature regimes during the first 12 weeks of growth

Years of genetic selection have caused an increase in growth rate and market body mass in agricultural poultry species compared to earlier genetic strains, potentially altering their physiological requirements. The objective of this study was to expose Hybrid Converter tom turkeys on a weekly basis to the recommended rearing temperature regime (TCON: control) or 4°C below the recommended standard (TTRT: treatment) to determine their thermal responses. Once per week for 12 weeks, 12 turkeys were individually exposed to either TCON or TTRT for a 2-h period. Surface temperatures of the breast (TBREAST), wing (TWING), drumstick (TDRUM), head (THEAD), and shank (TSHANK) were measured at 20-min intervals using an infrared camera, while a thermal data logger measured the skin surface temperature under the wing (TLOGGER) at 30-s intervals. The cloacal temperature (TCORE) was measured using a medical thermometer at the start and end of the exposure period. Regardless of exposure temperature, the TBREAST (TCON: P<0.001 and TTRT: P<0.001), TWING (TCON: P<0.001 and TTRT: P<0.001), and TDRUM (TCON: P<0.001 and TTRT: P<0.001) decreased from weeks 4 to 6 and remained constant from weeks 1 to 3 and 8 to 12. THEAD was elevated in week 2 (TCON: P<0.001) or week 3 (TTRT: P<0.001), TSHANK increased slightly during week 3 for both TCON (P<0.001) and TTRT (P<0.001), and TLOGGER (TCON: P<0.001 and TTRT: P=0.001) and TCORE (TCON: P<0.001 and TTRT: P<0.001) were lower during the first week. Thereafter, THEAD, TSHANK, TLOGGER, and TCORE remained constant. Exposure to TTRT resulted in lower TBREAST, TWING, and TDRUM compared to TCON. Generally, THEAD, TSHANK, TLOGGER, and TCORE were not affected by the different exposure temperatures. The data demonstrated that the degree of thermal response expressed is dependent on the location of measurement, age, and exposure temperature.

Minimum light intensity threshold to prevent negative effects on broiler production and welfare

1. Research focused on lower light intensity levels is required to set minimum standards appropriate for production and welfare of intensively housed broilers. The objective of this research was to study light intensity (0.1 to 10 lx) effects on Ross × Ross 308 and 708 genotypes. 2. Three experiments (35 d each) using 18 720 broilers were conducted with the initial experiment using two replicates of 0.1, 1, 5 and 10 lx. The second and third experiments examined 0.5, 1, 5 and 10 lx with treatments replicated twice in each experiment in a randomised complete block design with experiment acting as a block. In each experiment, mixed sex broilers from each genotype were housed in 6 equally sized pens per room. 3. In Experiment 1, the introduction of 0.1 lx at d 7 caused high levels of mortality and poor growth rate from d 7 to 14 and was discontinued. 4. In Experiments 2 and 3, increasing light intensity increased body weight gain (0-35 d) and feed intake (0-35 d) in a quadratic and linear fashion, respectively. Similarly, mortality corrected gain to feed ratio (FCR, 0-35 d) demonstrated a quadratic response with a maximum at 5 lx. Carcass, breast meat and skin, abdominal fat and drum skin, as a percentage of live weight, increased while drum bone and wing yield decreased in a linear fashion with increasing light intensity. Total carcass composition was unaffected by light intensity. 5. Genotype effects were numerous. No interactions were found between genotype and light intensity. 6. Ocular dimensions and the incidence of foot pad lesions decreased in a quadratic and linear fashion, respectively, with increasing light intensity. In contrast, welfare-associated gait score and mortality levels were not affected by light intensity. 7. It was concluded that performance, breast meat yield and bird welfare improved with increasing light intensity. The data support 5 lx as a minimum light intensity in broiler production.

The effect of toe trimming on production characteristics of heavy turkey toms

Trimming the 3 anterior toes on both feet at day of hatch to remove the claws, reduce bird scratching, and improve carcass grades is a common practice in the turkey industry. Changes in the method of trimming and the growth potential of turkeys since the majority of research on this topic was completed motivated this study with the objective of establishing the effects of microwave toe treatment on production characteristics of tom turkeys. Turkey toms (306 in total) were either toe trimmed at the hatchery using a microwave claw processor (T) or were sham treated only (NT). Poults were randomly assigned to 1 of 9 replicate pens for each treatment. Average BW, feed consumption, and feed efficiency were determined from BW and feed intake measured by pen on d 0, 7, 21, 42, 56, 70, 91, 126, and 140. On d 140, toms were sent to a commercial processing facility where 5 carcasses from each pen were examined for scratching and other externally visible damage. Average BW was higher for NT toms on d 91, 126, and 140, with final weights of 21.70 and 21.15 kg for NT and T birds, respectively. The T birds had lower feed consumption than their NT counterparts during the first and last week of production, but feed efficiency was unaffected. Carcass scratching (T, 13.33% of carcasses scratched vs. NT, 15.56%) and other carcass damages were not affected by treatment. Although overall mortality was not affected by treatment, the incidence of mortality due to skeletal causes, especially rotated tibia, was increased in T toms. Negative effects on performance and no effect on carcass quality suggest that toe trimming may not be required or recommended for heavy tom turkeys.

Safety assessment of consumption of glabrous canary seed (Phalaris canariensis L.) in rats

Canary seed is a nutrient-rich cereal grain; however, it has not been used in human food in part due to concerns regarding safety of consumption. Glabrous or hairless canary seed has potential human food use as trichomes are absent. The objective of the oral feeding studies reported here was to assess the safety of yellow and brown glabrous canary seed cultivars as human cereal foods. The first study was a 90-day rat oral toxicity study, which compared the effects of diets containing 50% of either brown dehulled glabrous, brown hulled glabrous, or brown hulled pubescent (hairy) hulled canary seed to a diet containing 50% wheat. No significant adverse effects were observed. In a 28-day and a 90-day study rats were fed yellow or brown glabrous canary seed groats in the AIN-76 diet at concentrations levels of 2.5%, 5% and 10%. The NOAELs in 90-day study were 5.15 g/kg/d and 5.23 g/kg/d for yellow and brown canary seed groats. Consumption of canary seed was associated with reduced incidence and severity of liver lipidosis as compared to controls. The combined results of these studies clearly demonstrate the safety of consumption of glabrous canary seed, and support its use as a human cereal grain.

Impact of daylength on the productivity of two commercial broiler strains

1. The impact of daylength on productivity in male and female broilers of two genotypes was studied in two replicated experiments. In each experiment, four lighting programs (14L:10D (14L), 17L:7D (17L), 20L:4D (20L) and 23L:1D (23L)) were used to study the relationships between productivity and daylength in two genotypes and both genders. 2. General Linear Model analysis was used to test for differences in daylength, genotype, gender and their interactions, and regression analysis to define relationships between productivity and daylength in experiment one and daylength differences in experiment two. 3. In experiment one, body weights at d 32 (P = 0·002) and d 39 (P = 0·011) were related in a quadratic fashion to daylength, with the heaviest birds raised under 20L. The growth curve at d 49 was similar in shape, and body weights under both 17L and 20L were significantly higher than under 14L and 23L (P < 0·001). In experiment two, data were similar, although the quadratic relationship was not significant. 4. Feed consumption was highest to d 39 or d 49 under 20L, and birds under 23L ate as much (d 39) or less feed (d 49) than under 17L. 5. Gain-to-feed efficiency (FCR) responded in a quadratic fashion, with maximum efficiency observed under the shortest daylength. 6. Mortality increased linearly with daylength for all time periods in both experiments.

Broiler chicken thigh and breast muscle responses to cold stress during simulated transport before slaughter

The effect of acute cold exposure was assessed on broiler physiology, breast and thigh muscle metabolites, and meat quality. In total, 160 male birds at ages of 5 and 6 wk were exposed to temperatures of -9 to -15°C (cold stressed) and +20°C (control) in a simulated transport chamber for 3 h before slaughter followed by 0 or 2 h of lairage. Bird physiology parameters, including core body temperature, live shrink, blood glucose, and muscle temperature, were assessed. Core body temperature was monitored every minute using i-Button data loggers, and live shrink and blood glucose were assessed. Total glucose and lactate concentrations at 30 h postmortem, as well as ultimate pH (pH(u)), color, and water-holding attributes were evaluated on pectoralis major muscle of breast and iliotibialis muscle of thigh. Birds were grouped based on their microclimate temperature to control and cold-stressed groups (0 to -8, -8 to -11, and -11 to -14°C). Significant (P < 0.05) decreases in core body temperature and breast and thigh muscle temperatures were observed at simulated transport temperatures below 0°C. In addition, higher (P < 0.05) live shrink and lower blood glucose values were observed as a result of 3-h exposure to temperatures below 0°C, exacerbated as temperature decreased further below -8°C. Thigh muscle was almost depleted of glycogen reserve compared with a significant but small reduction in breast muscle glycogen when exposure temperature was below -8°C. Similarly, much greater effects were observed on thigh pH(u) and quality attributes compared with breast. In addition, 84% incidence of the dark, firm, dry quality defect was observed in thigh meat (pH(u) > 6.4, L* < 44) compared with 42% incidence of dark, firm, dry in breast meat (pH(u) > 6.1, L* < 46) when transportation temperature was below 0°C. Results of this study showed that thigh muscle was affected more severely than breast muscle by exposure to cold temperatures before slaughter.

Broiler trailer thermal conditions during cold climate transport

Burlinguette, N. A., Strawford, M. L., Watts, J. M., Classen, H. L., Shand, P. J. and Crowe, T. G. 2012. Broiler trailer thermal conditions during cold climate transport. Can. J. Anim. Sci. 92: 109–122. Thermal environments within broiler transport vehicles are dependent on ambient conditions and, if poorly managed, can be a welfare concern. To effectively manage broiler transport, the environmental conditions throughout vehicles must be understood. Under standard commercial practices, temperature and humidity levels in double-trailer broiler vehicles were examined for a range of ambient temperatures (−24 to 11°C). During warmer ambient conditions (9.8°C) trailer roof vents and side curtains were all open, which resulted in a narrowing of the on-board temperature range (10.3 to 16.7°C). As ambient temperature cooled side curtains and some of the roof vents were closed. This resulted in increasingly variable and more extreme thermal conditions, with heat and moisture accumulated along the midline of the load near the front of the lead trailer and near the back of the rear trailer. At an ambient temperature of −22.1°C trailer temperatures ranged from −20.7 to 21.7°C with an estimated 58.6% of the load volume being exposed to temperatures below 0°C. In addition, the trailer humidity ratio rose 14.0 g kg−1 above ambient and conditions approached saturation (RH>80%) in 55.2% of the load volume. These results support the need to find a means to remove moisture and redistribute heat on broiler trailers during cold ambient conditions.

The effect of simulated cold weather transport on core body temperature and behavior of broilers

During the winter in Western Canada, broilers are routinely transported in ambient temperatures ranging from 0°C to -40°C, yet there is little research in this area. This study examined the physiology and behavior of broilers undergoing simulated transport at typical Western Canadian winter temperatures. Groups of 15 broilers aged 32 to 33 d were exposed to an air stream regulated to -5, -10, or -15°C. Birds were placed into a typical transport drawer. Following baseline observations, the drawer was placed into a test chamber where cold air was drawn past the birds for 3 h. Three replications were conducted at each temperature. The birds adjusted their position within the drawer based upon the temperature distribution within the drawer. In comparison to the baseline period, exposing the birds to a cold air stream caused them to avoid the front plane (P = 0.003) which was the coldest area within the drawer. The birds did not adjust their usage of the middle (P = 0.308) and rear (P = 0.640) planes, because these were the warmer areas within the drawer. The total amount of space the birds occupied within the drawer did not decrease when exposed to the test chamber (P = 0.669). The core body temperature (CBT) did not vary and was within the known normal range during the normal (P = 0.528), pre-chamber (P = 0.060), and post-chamber (P = 0.285) periods. The CBT of the birds significantly decreased during the in-chamber period (P < 0.001) and then increased during the lairage period (P < 0.001). The shrink loss (P = 0.981) and amount of time to resume feed consumption (P = 0.357) were not affected by exposing the birds to temperatures of -5°C and colder. Exposing birds to temperatures of -5°C and colder had a negative effect on the CBT of the birds. However, the birds demonstrated behaviors which mitigated the negative effect that cold exposure could have on their CBT.

Heat and moisture production by broilers during simulated cold weather transport

To ensure broiler welfare during winter transport, it is necessary to manage heat and moisture accumulation within the transport vehicles. Hence, it is necessary to determine heat production (HP) and moisture production (MP) rates under representative conditions. An environmental chamber containing a standard transport drawer was used. Cold air was drawn from outside the building, warmed to the desired temperature, and passed through the drawer at 0.35 m(3)/s. Broilers were fasted for 7 h, placed into the drawer, and exposed to test conditions within the chamber for 3 h. Air temperature and RH were measured upstream and downstream of the insulated bird compartment at 1-min intervals. Differences in the paired temperature and RH values were used to calculate sensible HP and MP for each 1 min of confinement. Effects of temperatures between -8 and -18°C and a control (+20°C) were measured for birds in 2 conditions. In condition A, there were 15 birds/drawer. Birds were 32 to 33 d old and weighed 1.8 kg. Packing density was approximately 27 kg/drawer (31 kg/m(2)). In condition B, there were 19 or 22 birds/drawer. The drawers with 19 birds contained birds that were 39 to 40 d old that weighed 2.68 kg. In the drawers with 22 birds, the birds were 35 to 36 d old and weighed 2.29 kg. In either case, the packing density was approximately 50 kg/drawer (59 kg/m(2)). Thus, the birds in condition B were bigger, more numerous, and more tightly packed than the birds in condition A. Drawers were balanced for sex. At +20°C, HP and MP rates were similar to other published values. However, for both conditions, HP and MP rates increased with decreasing exposure temperatures. In condition A, HP was 6.08 ± 0.43 W/kg and MP was 4.46 g/h per kg at 20°C compared with 87.5 ± 10.3 W/kg and 22.08 ± 5.05 g/h per kg at -15°C. In condition B, HP was 8.12 ± 1.24 W/kg and MP was 5.53 ± 1.68 g/h per kg at 20°C compared with 45.92 ± 1.95 W/kg and 12.33 ± 0.22 g/h per kg at -18°C.

Effect of light intensity on broiler production, processing characteristics, and welfare

Manipulation of light intensity is an important management tool affecting broiler production and well being. Despite considerable research on light intensity, there is still a debate on the optimum level to be used for intensively housed broilers. Two trials were conducted with the objective of investigating the effect of light intensity, within the practical levels at confinement barns (1, 10, 20, and 40 lx), on production, processing characteristics, and welfare of broilers raised to 35 d of age. Each light intensity treatment was replicated in 2 environmentally controlled rooms in each trial with 950 Ross × Ross 308 chicks per room. Data were analyzed as a randomized complete block design with trial serving as a block. All chicks were exposed to 40 lx of light intensity and 23 h of light for the first 7 d followed by treatment light intensity and 17 h of day length thereafter. Body weight and feed consumption were determined at 7, 14, and 35 d of age. At the end of each trial, 60 birds per treatment were processed to determine the detailed meat yield. Skeletal and footpad and ocular health were monitored at 31 and 32 d of age, respectively. Body weight, feed consumption, feed:gain ratio, and mortality were unaffected by light intensity. Carcass, thigh, and drum yield as a percentage of live weight decreased linearly with increasing light intensity. The 1 lx treatment resulted in heavier wings as a percentage of live weight. Light intensity had no effect on skeletal health, but ulcerative footpad lesions decreased linearly with increasing light intensity. Birds exposed to the 1 lx treatment had heavier and larger eyes. In conclusion, light intensity did not affect broiler production and mortality but did affect carcass characteristics. The 1 lx light intensity treatment had a negative effect on broiler welfare as demonstrated by increased ulcerative footpad lesions and eye size.

Temperature gradients in trailers and changes in broiler rectal and core body temperature during winter transportation in Saskatchewan

Temperature conditions inside commercial trailers transporting market-age broilers during four winter journeys were measured, and changes in the rectal and core body temperature of birds were quantified. Pre-selected modules were equipped with data loggers recording temperature every 72 s. Rectal temperatures were taken from eight birds in each of four modules immediately before and after each trip, and two or three birds, with temperature recording implants, were placed in each of two selected modules. Temperature heterogeneity was found among modules on all loads with average crate temperatures ranging from 10.9 to 30.7, 8.9 to 28.1, 2.5 to 26.1 and -0.7 to 16.5°C for transportation times of 191, 193, 178 and 18 min and ambient temperatures of -7.1, -27.1, -28.2 and -18.4°C, respectively. Wet birds, condensation and frost provided evidence for moisture accumulation during transportation. Body temperature recordings indicated the potential for the development of both hypothermia and hyperthermia, showing that cold stress can occur near air inlets and heat stress in poorly ventilated areas. Passive ventilation inside trailers resulted in crate temperatures 17.7 to 55.2°C above outside temperature. Mortality ranged from 0.7 to 1.4% but several deaths occurred during lairage, prior to processing. A heterogeneous distribution of airflow resulted in undesirable temperate and humidity conditions for some birds. Key words: Broiler, transportation, temperature gradient, mortality, cold weather

Effect of Quantum phytase on nutrient digestibility and bone ash in White Leghorn laying hens fed corn-soybean meal-based diets

The efficacy of an Escherichia coli 6-phytase supplementation (Quantum) on nutrient digestibility-retention and bone ash in laying hens fed corn-soybean meal (CSM) diets was investigated. White Leghorn hens (Shaver and Bovan strains) were fed CSM diets containing 0.35% (positive control, PC), 0.25% (negative control 1, NC1), or 0.15% (negative control 2, NC2) nonphytate P from 21 to 61 wk of age. Six more diets were manufactured by supplementing the negative control diets with 200, 400, and 600 units per kilogram of exogenous phytase resulting in a total of 9 treatments. Each dietary treatment x strain subclass was replicated twice with 6 hens per replication. Fecal and ileal digesta samples were collected at 42 wk of age to determine apparent nutrient digestibility or retention. Left tibiae were collected at 42 and 61 wk of age to determine bone ash. The coefficients for ileal digestibility and fecal retention for protein were higher (P < 0.05) for the unsupplemented negative control treatments compared with the PC. A linear reduction in phytate digestibility and ileal protein digestibility was reported with increasing levels of phytase to the NC1 diet. Phytase addition to the NC1 treatment resulted in a linear decrease in the digestibility of amino acids except for methionine and proline. Significantly higher phytate digestibility was demonstrated with the NC2 treatment containing 400 units per kilogram of phytase compared with the PC. Tibial bone ash percentage was higher (P < 0.05) in 61-wk-old hens fed 200 or 400 units per kilogram of phytase-supplemented NC2 diets. Significantly higher diet AME and fecal protein retention were demonstrated for Shaver hens in comparison to the Bovan hens. Overall, the Quantum phytase was not efficacious at improving nutrient digestibility-retention in laying hens fed CSM diets deficient in nonphytate P.

Fishy-egg tainting is recessively inherited when brown-shelled layers are fed canola meal

Feeding canola meal to brown-shelled laying hens can result in the production of eggs with a fishy odor. This fishy taint is caused by the accumulation of trimethylamine (TMA) in the yolk. Trimethylamine is produced by the bacterial fermentation of choline in the lower gut. Fishy-egg tainting is caused by a SNP in flavin-containing monooxygenase 3 (FMO3 c.984A > T), rendering the hen unable to metabolize TMA into the nonodorous TMA N-oxide. The purpose of this study was to characterize the inheritance pattern of fishy-egg tainting when hens are fed canola meal at levels reflecting maximum use based on conventional formulation of laying hen diets. Additionally, we wished to examine the effect of choline source (choline chloride vs. canola meal) on egg tainting. In the first of 2 experiments, 6 hens per genotype (AA, AT, and TT) were allocated to each of 5 dietary treatments (0, 6, 12, 18, or 24% canola meal) for 4 wk. Three yolks per hen collected in the last week of the trial were analyzed for TMA concentration. There was a significant linear regression (P < 0.05) between yolk TMA concentration and dietary canola meal level for hens of the TT but not the AA or AT genotypes. In the second experiment, 6 hens of the TT (homozygous tainting) genotype were each assigned to 1 of 9 dietary treatments: the 5 diets used in the first experiment plus 4 diets that used choline chloride to match the total choline concentration of the 6, 12, 18, and 24% canola meal diets, respectively. Three yolks per hen were analyzed for TMA concentration. A significant response in yolk TMA concentration was seen with the canola meal diets but not the choline chloride diets. We conclude that fishy-egg tainting is recessively expressed when hens are fed canola meal at levels from 12 up to 24% inclusion. We also conclude that choline chloride, at levels typical of commercial egg production, will not lead to egg tainting.

Cryopreservation of germplasm from chickens kept in Canadian research institutions

Twenty-three genetically distinct lines of chickens are maintained as living populations by Agriculture and Agri-Food Canada and Canada’s eight Faculties of Agriculture. Historically, cryogenic storage of avian genetic material has been difficult, but we have developed techniques of gonadal transplantation to allow recuperation of stored genetic material into living birds. Gonads from 1660 day-old chicks or late-term embryos (810 females and 850 males) from 18 chicken populations from four Canadian institutions were harvested and cryopreserved using dimethylsulfoxide as a cryoprotectant. Future efforts will be directed to completing the collection of the populations kept in Canadian publicly-funded institutions that conduct agricultural research. Key words: Chicken, genetic resources, cryopreservation, gonads

The effect of dietary sinapic acid (4-hydroxy-3, 5-dimethoxy-cinnamic acid) on gastrointestinal tract microbial fermentation, nutrient utilization, and egg quality in laying hens

Plant-based simple phenolics are natural antimicrobial and antioxidant compounds that may possess biological activity when included in animal diets. Previous work in our lab has shown that sinapic acid (SA) found in canola meal improves nutrient retention and alters gut microbiota when fed at low levels (0 to 0.10%) to broiler chickens. It was of interest to investigate the effect of dietary SA in laying hens that possess a more mature intestinal microbiota. Therefore, 2 experiments were conducted to determine the effects of dietary SA on performance, nutrient digestibility, and egg quality in laying hens. Sinapic acid (Sigma-Aldrich, 98% purity) was included in diets at 0, 0.025, 0.050, and 0.075% in experiment 1, and 0 and 0.5% in experiment 2. Both experiments were conducted for 21 d. Dietary treatment did not affect production traits and gastrointestinal tract volatile fatty acid production in either experiment. Apparent metabolizable energy and protein digestibility were also unaffected by treatment in experiment 1, but in experiment 2, feeding 0.5% SA increased both AME(n) and protein digestibility in comparison to the unsupplemented control. Egg weight, albumen weight, yolk weight, egg specific gravity, shell thickness, and Haugh units were not significantly affected by dietary treatments in either of the experiments. Sinapic acid was not detected in eggs from experiment 1 but in experiment 2, low levels of SA were detected in both the yolk and albumen of eggs from hens fed 0.5% SA. Further research is needed to more completely define the relationship between dietary SA level and nutrient utilization as well as the accumulation of SA in egg components.

Nutritional and physiological effects of dietary sinapic acid (4-hydroxy-3,5-dimethoxy-cinnamic acid) in broiler chickens and its metabolism in the digestive tract

Sinapic acid (SA) is a major free phenolic acid in rapeseed meal, with the majority found in the esterified form of sinapine. Two experiments were conducted to delineate the effect of dietary SA on broiler chickens, in terms of performance, toxicity, and nutrient digestibility. In the first experiment, 80 male broiler chicks were randomly assigned to 5 diets adequate in all nutrients and containing 0, 0.05, 0.10, 0.15, or 0.20% dietary SA. Performance from 0 to 18 d of age and the relative size of all the internal organs and intestines were not affected (all P>0.05) by dietary treatment. In addition, dietary SA had no effect (P>0.05) on the serum activity of creatine kinase and lactate dehydrogenase, which indicated that there was no damage to skeletal muscle, heart muscle, liver, kidneys, or brain. The objectives of the second experiment were to investigate the effect of SA on nutrient retention and to study the retention of SA in the digestive tract. Male broiler chicks (96) were randomly assigned into 4 treatments containing dietary SA at 0, 0.025, 0.05, and 0.10%. Dietary SA at the 0.025% level increased feed intake compared with control (P<0.05). Regression analysis indicated a quadratic response for both weight gain and feed intake (P<0.05) as SA increased in the diet. Again, dietary SA did not affect the relative weights of bursa of Fabricius, liver, kidney, or digestive tract. Nitrogen-corrected AME and protein digestibility were not affected by SA level. A negative linear relationship was found between dietary SA level and apparent ileal digestibility of Met, Thr, Ser, Pro, Gly, Ala, and Phe. Sinapic acid disappearance in the ileum was above 97% for all SA levels, whereas apparent SA retention in excreta ranged from 64 to 79%. Sinapic acid at dietary levels investigated in this research is apparently not toxic to broiler chickens but may have a negative effect on amino acid digestibility at higher levels.

The efficacy of quantum phytase in a forty-week production trial using white leghorn laying hens fed corn-soybean meal-based diets

Microbial phytase is a prominent feed enzyme used in animal feeds, but there is relatively little information on its use in laying hen diets. In this experiment, an Escherichia coli 6-phytase (Quantum) was evaluated for its efficacy in a 40-wk laying hen production trial. A total of 1,080 White Leghorn hens (540 each of Shaver and Bovan strains) were fed mash corn-soybean meal-based diets containing 0.35% (positive control, PC), 0.25% (negative control, NC1), or 0.15% (NC2) nonphytate phosphorus (NPP). Six more diets were manufactured by supplementing the negative control diets with 200, 400, and 600 U/kg of exogenous phytase, resulting in a total of 9 treatments. Each dietary treatment x strain subclass was replicated 4 times with 5 adjoining cages per replicate (3 hens per cage) in a randomized complete block design. Production performance was measured from 21 to 61 wk of age. Only minor differences in production characteristics were found between the PC and NC1 treatments regardless of phytase addition, indicating that 0.25% NPP resulted in P intake that was at or above the hen's requirement. In contrast, the hens fed 0.15% NPP diet without phytase supplementation had significantly (P < 0.05) reduced total hen housed egg production and body weight at 61 wk of age in comparison to the PC treatment, whereas the incidence of soft-shelled, cracked, and broken eggs was increased significantly (P < 0.05) in hens fed the NC2 diet. Addition of phytase to the NC2 diet improved these production characteristics to levels equal or better than the PC diet. The results indicated that Quantum phytase was efficacious in corn-soybean meal-based diets fed to White Leghorn laying hens and can be used to reduce diet supplementation with inorganic phosphorus.

Influence of dietary nutrient density, feed form, and lighting on growth and meat yield of broiler chickens

The objective of this study was to examine main and interactive effects of nutrient density (ND), feed form (FF; mash, pellet), and lighting program (12L:12D, 20L:4D) on production characteristics and meat yield of broilers raised to 35 d of age. Diets (starter, grower, and finisher) were formulated so that amino acid levels were in proportion to the dietary energy level. Lighting programs were initiated at 4 d of age. Body weight was not affected by ND when diets were fed in a pellet form but decreased in a linear manner with lower ND when fed as a mash. Final BW of birds fed mash were less than those of birds fed pellet diets. Feed to gain ratio decreased with increasing ND but was not affected by FF. Feed intake decreased with increasing ND and was lower for birds fed mash. The effect of ND on feed intake was less when birds were fed mash in contrast to pellet diets (P(ND x F) < 0.0001). Dietary ND had no effect on mortality, but feeding mash decreased mortality (3.8%) compared with feeding pelleted feed (5.6%). Lighting programs affected production characteristics independently of ND and FF. Use of 12L:12D reduced BW, feed to gain ratio, feed intake, and mortality compared with 20L:4D. Similarly, carcass components were not affected by ND when fed in pellet form but decreased with lower ND when fed as a mash. Overall, carcass yields were reduced when broilers were fed mash or provided with 12L:12D. Female birds had higher carcass yields and increased proportional breast meat deposition compared with males.

The impact of nutrient density, feed form, and photoperiod on the walking ability and skeletal quality of broiler chickens

The aim of this study was to examine the main and interaction effects of 3 dietary nutrient densities (low-, medium-, high-density), 2 feed forms (mash, pellet), and 2 lighting programs (20L:4D, 12L:12D) on the walking ability and skeletal quality of broiler chickens raised to a young age (35 d). Forty-eight birds per treatment (nutrient density x feed form x lighting program subclass) were randomly selected (0 d) for assessment of their gait score (GS) and BW at 11, 18, 25, and 32 d. Samples of birds from various GS classifications were selected at 32 d for radiographs and histology of the femur and tibiotarsus. Bone ash (BA) content was evaluated at 35 d from the right tibiotarsus to assess bone quality. Overall, the mean GS values were low (GS <1). An interaction existed between lighting and sex. Males provided with 20L:4D had a higher GS (0.74) than females (0.45), and this score was greater than for broilers provided with 12L:12D (0.34 and 0.26 for males and females, respectively). Feeding mash reduced the GS (0.29) compared with pellet rations (0.62). The GS increased with age, and by 32 d 2.43% of birds had a GS >/=3. Broilers fed mash had a higher BA content (50.6%) than birds fed pellet diets (49.8%), and the 12L:12D value (50.5%) was greater than for 20L:4D (48.9%). Last, males had a lower BA content (49.8%) than females (50.6%). A positive correlation existed between BW and GS based on sex, where BW at 11, 18, and 25 d affected bird mobility at 32 d (r(2) = 0.39, 0.49, and 0.50 for males; r(2) = 0.34, 0.37, and 0.36 for females, respectively). Radiography and histology were unaffected by GS. This study confirmed that a reduced growth rate improved GS but also demonstrated that overall bird mobility was good and the incidence of skeletal disease was low.

Total dust and endotoxin in poultry operations: comparison between cage and floor housing and respiratory effects in workers

OBJECTIVE

The objective of this study was to assess respiratory outcomes and environmental exposure levels of workers in cage-housed and floor-housed poultry operations.

METHODS

Poultry operations were evaluated for total dust, endotoxin, and ammonia, and respiratory symptoms and lung function tests of workers were conducted.

RESULTS

Workers in floor-housed poultry operations had significantly greater exposures to total dust and ammonia, whereas workers from cage-housed poultry operations reported greater frequency of current and chronic symptoms overall and significantly greater current and chronic phlegm (39% vs 18% and 40% vs 11%, respectively). Endotoxin concentration (EU/mg) was a significant predictor (P = 0.05) of chronic phlegm for all poultry workers.

CONCLUSIONS

Greater endotoxin concentration in the presence of significantly lower total dust, in conjunction with greater respiratory symptoms in workers from cage-housed poultry operations, as compared with workers from floor-housed poultry operations, appears to indicate that differences in environmental exposures may impact respiratory outcomes of workers.

Response of Turkey Poults to Soybean Lectin Levels Typically Encountered in Commercial Diets. 2. Effect on Intestinal Development and Lymphoid Organs

Lectins are capable of altering intestinal morphology by binding to and disrupting the intestinal brush border membrane. They are also known to alter the weight of lymphoid organs. Therefore, we evaluated the effect of soybean lectin (SBL) on intestinal morphology and lymphoid organ weights of poults fed diets containing SBL. Dietary treatments evaluated in this study included a cornstarch and casein-based control (lectin-free) semipurified diet (PD) and semipurified diets containing 0.024 or 0.048% SBL (PDL and PDH, respectively). Experimental diets were fed from hatch to 14 d. Morphological evaluation of the intestine involved measurement of the villi height and perimeter, crypt depth, villus:crypt, and thickness of the muscle layer in the jejunum. Intestinal physical characteristics were also determined by measuring intestinal weight, length, and volume. Results indicated that 0.048% SBL in PDH increased villus:crypt and reduced total intestinal length in turkey poults. In addition, both the 0.024 and 0.048% dietary SBL levels reduced thymus weights. It was concluded that dietary SBL up to 0.048% enhanced intestinal development by increasing villus:crypt, but might alter the structural integrity of lymphoid organs.

Feeding high levels of lupine seeds to broiler chickens: plasma micronutrient status in the context of digesta viscosity and morphometric and ultrastructural changes in the gastrointestinal tract

This work examines the effects of lupine-based diets on the status of the host's riboflavin and zinc. Test diets contained 35% soybean meal (control) or raw (40%) or dehulled (35%) lupine seed meal and were isocaloric (13.4 MJ of AME/kg) and isonitrogenous (23% crude protein). Each diet was offered ad libitum to a group of 16 male commercial broiler chicks for 21 d, starting at 1 d of age. Broilers fed lupine diets had lower feed intakes and growth rates. All sections of the intestinal tract were significantly enlarged (P < 0.01) in all groups fed lupine-based diets in comparison with broilers fed the soybean meal diet, but there were no differences in the morphologies of the mucosa, submucosa, muscularis, or serosa. Increased size of the duodenum, jejunum, and ileum was predominantly attributed to the increase in length rather than intestinal tissue mass. Hence, the enlargement of the intestinal tract was consistent with physiological hyperplasia and not pathological remodeling and hypertrophy. Overall, broilers fed lupine-based diets had more viscous digesta than those fed the soybean meal diet, but the differences were statistically not significant. Blood plasma Zn concentration did not differ between broilers fed lupine-based diets and those fed soybean-meal-based diets, and all broilers fed lupine-based diets had significantly higher (P < 0.001) riboflavin concentrations. In this context, it is apparent that the bioavailability of these micronutrients from lupine diets is not compromised. Intestinal tissue hyperplasia may be interpreted as physiological adaptation to increase absorptive capacity and thus maximize absorption of essential nutrients in the face of antinutritional factors in the diet.

Pathogenesis of Ascites in Broilers Raised at Low Altitude: Aetiological Considerations Based on Echocardiographic Findings

This study reports novel insight into the aetiology of pulmonary hypertension and ascites in broiler chickens. The scope of measurements was focused on anatomical and functional parameters, and blood flow patterns in leghorns (resistant to ascites), fast-growing broilers (susceptible to ascites), broilers developing ascites, and ascitic broilers evaluated in vivo using echocardiography, and further examined in the context of postmortem findings. Both, in vivo observed features and postmortem findings, showed clear differences between broilers and leghorns, and between normal and ascitic broilers. Abnormalities in the heart chamber geometry and blood flow patterns were detected upon echocardiographic examination in all ascitic broilers. Right and left atrio-ventricular (AV) valve regurgitation were common findings in ascitic broilers and some apparently normal broilers, with left AV valve insufficiency being a predominant feature with respect to degree and frequency of occurrence. Blood flow disturbances were not detected in leghorns. Left ventricular fractional shortening (functional parameter) was considerably reduced (P < 0.01) in ascitic birds (mean: 21.7 +/- 2.0 SE) in comparison with normal broilers (mean: 39.1 +/- 3.6 SE), or leghorns (mean: 43.3 +/- 2.4 SE). The presented findings indicate that pathological and functional changes in the left ventricle and atrium play a significant role in the pathogenesis of ascites in broilers. Severe dilation of the left atrium and pulmonary veins seen on postmortem examination, as well as regurgitant blood flow in the left atrium, demonstrated by Doppler study in ascitic birds, provide evidence that chronically elevated pressure in the left atrium is involved in the aetiology of pulmonary hypertension and ascites in fast-growing broilers.

Response of turkey poults to soybean lectin levels typically encountered in commercial diets. 1. Effect on growth and nutrient digestibility

Lectins are known to bind to the intestinal brush border membrane and induce antinutritional effects such as disruption of the brush border membrane (BBM) and reduced nutrient digestibility in laboratory rodents. Because soybean lectin (SBL) is usually present in poult starter diets, 2 similar experiments with starting turkey poults were conducted to investigate the effects of purified SBL on growth performance and nutrient digestibility. Experimental diets were a corn starch-casein based control (lectin-free) semipurified diet (PD), semipurified diets containing 0.024 or 0.048% soybean lectin (PDL, PDH), and a corn-soybean meal diet (SBD). Experimental diets were fed from hatch to 14 d. Antibodies specific for soybean lectin were detected in the serum of poults fed the PDL and PDH diets, implying that the SBL in these diets remained active in the digestive tract. Poults fed the control PD or SBD grew equally well. The 0.024% SBL level in PDL had no significant detrimental effect on any parameters assessed in the 2 experiments. In contrast, the 0.048% SBL level in the PDH gave inconsistent results for feed efficiency (FE) and brush border enzyme levels. For instance, on d 6 in experiment 2, poults fed the PDH had poorer FE (P < 0.05) compared with the control PD treatment, but had similar FE to poults fed the PD in experiment 1. In conclusion, SBL present at levels up to 0.024% of the diet would not cause antinutritional effect in turkey poults up to 2 wk of age.

Effect of dietary calcium, 25-hydroxycholecalciferol, or bird strain on small intestinal phytase activity in broiler chickens

Broilers chickens have limited ability to utilize phytate phosphorus (PP), and the influence of nutrients on the activity and efficacy of intestinal phytase is unclear. Therefore in a 2 x 2 x 2 factorial experiment, male chicks were fed 0 or 0.21 mg/kg 25-hydroxycholecalciferol (25-OH D3), 4 or 9 g/kg Ca supplied from CaCO3 or Ca malate from 14 to 24 d of age (six pens/treatment, eight birds/pen). Source of Ca had no effect on tibia ash, intestinal phytase activity, or apparent ileal PP hydrolysis. Phytase activity (Vmax) within brush border vesicles prepared from small intestinal mucosa was greater in chicks fed 4 vs. 9 g/kg Ca (P < or = 0.05). Similarly, birds fed 4 vs. 9 g/kg Ca were able to hydrolyze an additional 24.36% PP (P < 0.01). Intestinal phytase activity and apparent ileal PP hydrolysis were not affected by 25-OH D3 supplementation, but tibia ash was improved by 2.7% (P < 0.01). A subsequent experiment validated the effect of dietary Ca (4 and 9 g/kg) and elucidated differences between strains (Ross 308 and Hubbard x Peterson) from 8 to 22 d of age (six pens/treatment, eight birds/pen). The strains responded similarly to dietary Ca in terms of intestinal phytase and apparent ileal PP hydrolysis. Intestinal phytase activity was 9% greater in birds fed 4 vs. 9 g/kg Ca (P < 0.05) and apparent ileal PP hydrolysis was 11.9% greater (P < 0.02). In conclusion, a typical dietary Ca concentration (9 g/kg) reduced intestinal phytase activity and apparent ileal PP hydrolysis.

Lesions of the pericardium and their significance in the aetiology of heart failure in broiler chickens

The present study focuses on lesions of the pericardium commonly observed in fast growing broilers. These lesions are examined in the context of electrophysiological and functional changes associated with cardiac performance and patho-physiology in broilers succumbing to acute or chronic heart failure. Typical lesions involving the pericardium in fast growing broiler chickens included: (1) excessive pericardial effusion, (2) locally extensive or focal adhesions between parietal and visceral components of the pericardium, (3) fibrous deposits on visceral pericardium, and (4) thickened pericardium. Echocardiographic evidence indicated that severe pericardial effusion and/or adhesions may have a restrictive effect on heart pump function, where both diastolic and systolic function of the heart may be affected. Electrocardiographic data showed a strong trend indicating that pericardial adhesions may be associated with ventricular arrhythmia and increased risk of sudden death in fast growing broilers. Relatively high levels of matrix metalloproteinase MMP-2 activity have been found in pericardial effusions from affected chickens, suggesting a possible involvement of this enzyme in the aetiology of pericardial lesions. The present results indicate that pericardial lesions may be associated with biochemical, morphological, electrophysiological, and functional changes occurring in the hearts of broilers succumbing to acute or chronic heart failure and ascites.

Investigating the possibility of monitoring lectin levels in commercial soybean meals intended for poultry feeding using steam-heated soybean meal as a model

Native soybean lectins (SBL) could potentially have deleterious effects on young animals. The objectives of this study were to determine the optimum processing temperature and time at which SBL is inactivated and to investigate the possibility of using urease activity (UA) to predict residual lectin levels in soybean meal (SBM). Raw defatted SBM was steam-heated at incremental temperatures between 90 and 120 degrees C for 5 to 20 min in an autoclave. The processed meals were subjected to native-PAGE and measurement of total carbohydrate-binding lectin (TCBL), agglutinating lectin (AL), UA, and trypsin inhibitor (TI). Processing severity was evaluated by determining protein solubility in 0.2% potassium hydroxide. Results indicated that levels of all antinutrients (TCBL, AL, UA, and TI) decreased with increasing processing temperature (P < 0.05). The intensity of the lectin band on the electrophoresis gel was considerably reduced when meal was heated at 100 degrees C for 5 min. This result implied that lectin inactivation occurred at 100 degrees C. More than 90% of all the original antinutrient levels in the raw meal were destroyed when meals were heated at 100 degrees C for 5 min. Meals processed at 100 degrees C for 5 to 20 min had protein solubility values (80 to 85%) indicative of adequate processing. The denaturation pattern of UA was highly correlated with that of SBL (r > or = 0.73), indicating that UA could be used for monitoring lectin levels in commercial meals. We concluded that UA of 0.03 to 0.09 units of pH change are indicative of adequately processed meals that contain negligible lectin levels.

Interaction of wheat micronization and cultivar on its feeding value for broilers

Three experiments were conducted to investigate the interaction between micronization and cultivar of wheat on grain chemical composition and feeding value for chickens. Micronized whole grain feeding was evaluated in one experiment using inclusion levels of 10 and 50% for starter and grower diets, respectively. Dietary enzyme was used in two other experiments to study its interaction with micronization and genotype of wheat. Wheat cultivars Genesis, Kyle, and Katepwa were micronized at 100°C for 50 s and incorporated into broiler diets. Micronization improved overall feed efficiency, but did not always increase body weight. When feeding whole grain to birds, micronization improved feed efficiency from 21 to 42 d and 0 to 42 d, but did not affect final body weight. Micronization of wheat cultivars reduced early growth rate of all birds, regardless of wheat form in the diets. Micronization did not impact AME and digesta viscosity. Cultivar Kyle had a higher dietary AME and a lower digesta viscosity, and resulted in feed efficiency and weight gain values superior to those of either Genesis or Katepwa (exps. 2 and 3). Enzyme increased weight gain, feed efficiency and dietary AME, and decreased digesta viscosity. Key words: wheat, cultivars, micronization, AME, broilers

The digestibility and content of amino acids in toasted and non-toasted canola meals

A study was conducted to determine the level and digestibilities of amino acids and the level of glucosinolates in toasted and non-toasted canola meal samples produced in commercial crushing plants in western Canada. A total of 26 non-toasted and 31 toasted canola meals samples were analyzed for apparent ileal amino acid digestibilities using broiler chickens between 21 and 28 d of age. Commercially toasted canola meal contained 5.6 g 16 g-1 N (range 5.3–5.9) of Lys with a digestibility ranging from 65.5 to 85.7% (mean = 78.0%). Non-toasted canola meal contained 6.0 g 16 g-1 N (range 5.7–6.3) Lys with digestibility values ranging from 87 to 92% (mean = 89.7%). Toasted canola meal had an average total digestible amino acid content (not including Tyr and Trp) of 69.6 g 16 g-1 N (range 56.6–75.6) while non-toasted canola meal had 77.6 g 16 g-1 N (range 73.1–82.0). The levels of aliphatic glucosinolates in the toasted (6.16 μmol g-1 meal, range 1.2–12.5) and non-toasted meals (10.5 μmol g-1 meal, range 7.8–15.1) were low and likely of nonutritional consequence. In conclusion, non-toasted canola meal contains higher levels of digestible amino acids than conventional toasted canola meal and therefore consideration should be given to modifying commercial systems to produce a non-toasted meal. Key words: Canola meal, toasting, amino acid, digestibility, glucosinolates

Effects of micronization, tempering, and flaking on the chemical characteristics of wheat and its feeding value for broiler chicks

Five experiments were conducted to study the effects of micronizing, tempering and flaking of wheat (cv. Genesis) on the chemical characteristics and its feeding value for broiler chicks. Samples of wheat were micronized (infrared invisible band with wavelengths of 1.8 to 3.4 µ) at 90, 105, and 120°C for 50 s, with or without tempering to 20% moisture, and with or without flaking. Micronization at 120°C produced negative effects on weight gain and feed efficiency (0–18 d). Tempering reduced protein solubility in 0.2% KOH, increased the solubility of dietary fibre, and increased in vivo digesta viscosity and in vitro extract viscosity as well as diet AME. Flaking wheat had no effect on broiler performance in exps. 3 and 4, but decreased growth rate and feed efficiency in exp. 5 despite improved dietary AME. Flaking decreased protein solubility at 120°C but had little effect at lower temperatures. The lowest protein solubility was found in the sample that was tempered, micronized at 120°C, and then flaked. In conclusion, micronization at 90 and 105°C improved the feeding value of wheat for broiler chickens. Tempering and flaking may be beneficial at lower micronization temperatures, but can result in lower nutritional value at higher micronization temperature. Key words: Wheat, micronization, metabolizable energy, broiler

Performance of two strains of laying hens fed ground and whole barley with and without access to insoluble grit

The live performance from 19 to 43 wk of age of two strains of commercial White Leghorn hens fed two levels of whole barley (0 or 60%) and insoluble grit (0 or 4 g/bird per wk) was compared. The 0 and 60% whole barley diets differed only in feed form and were formulated to the same nutrient specifications. No dilution of nutrients or ingredients occurred. The 0% whole barley diet was fed in mash form. The 60% whole barley diet was fed as whole grain and mash concentrate blended into a complete diet and fed in the same feed trough. Feeding whole barley reduced egg production, feed efficiency, and egg specific gravity and increased feed intake, egg weight, and body weight gain. Access to insoluble grit had no effect on any of the production variables measured. The two strains of hens responded similarly to whole barley but differed in feed intake, feed efficiency, egg weight, egg specific gravity, and body weight gain. Feeding whole barley combined with a mash concentrate depressed hen performance compared to birds fed a similar diet in mash form. Strain of hen and access to insoluble grit did not alter the response to feeding whole barley.

Influence of whole barley and grit on live performance and health of turkey toms

Live performance to 96 d was compared for 1,584 turkey toms reared on diets containing four levels of whole barley and two levels of insoluble grit (0 or 9 g/bird per wk). Nutrient specifications for all diets were similar. The six dietary treatments were 1) 0% whole barley plus grit, 2) Treatment 1 minus grit, 3) grit plus 5% whole barley at 0 d increasing to 35% by 19 d, 4) grit plus 5% whole barley at 0 d increasing to 50% by 19 d, 5) Treatment 4 minus grit, and 6) grit plus 5% whole barley at 19 d increasing to 50% by 40 d. The concentrate blended with the whole barley was fed as crumbles or pellets. Nutrients were not diluted. Compared to the control treatments, feeding 35% or more whole barley temporarily reduced weight gain and increased feed:gain prior to 68 d. Cumulative weight gain was reduced in Treatments 3 and 5 compared to treatments in which no barley was fed. Cumulative feed:gain was increased in Treatment 5 compared to Treatments 2 and 3. Total mortality and leg and skeletal problems were reduced in treatments where whole grain slowed early growth rate. Feeding grit had no effect on the live performance of birds fed similar levels of whole barley. In treatments in which whole barley was introduced at 0 d, gizzard pH was decreased at 18 d, and gizzard weight was increased at 32 d. Jejunal viscosity was unaffected by dietary treatment.

Necrotic enteritis: effect of barley, wheat and corn diets on proliferation of Clostridium perfringens type A

Necrotic enteritis, caused by Clostridium perfringens type A, is more prevalent in broilers fed wheat or barley diets than in those fed a corn diet. We compared the effects of wheat, barley and corn diets on in vitro proliferation of C. perfringens type A. Bacteria were inoculated into the supernatants delivered from either digested or non-digested barley, wheat and corn diets mixed with thioglycollate medium (1:3). Colony forming units were counted following incubation for 6 h at 40 degrees C. There were no significant differences in clostridial proliferation among non-digested diets. Bacterial proliferation in the digested wheat and barley diets was significantly higher than in the digested corn diet. These findings suggest that the increased incidence of necrotic enteritis in broilers fed barley and wheat diets compared with those fed a corn diet may be due in part to increased clostridial proliferation associated with the wheat and barley diets, or to decreased proliferation associated with the corn diet.