Chromium propionate in turkeys: effect on performance and animal safety.

Two hundred eighty-eight male Nicholas Large White turkey poults were used to determine the effect of supplementing turkeys with chromium propionate (Cr Prop) from 1 to 84 d of age on performance and animal safety. Treatments consisted of Cr prop supplemented to provide 0, 0.2, or 1.0 mg Cr/kg diet. One mg of supplemental Cr is 5 times (x) the minimal concentration of Cr Prop that enhanced insulin sensitivity in turkeys. Each treatment consisted of 8 floor pens with 12 poults per pen. Turkeys were individually weighed initially, and at the end of the starter 1 (d 21), starter 2 (d 42), grower 1 (d 63), and grower 2 phase (d 84). On d 85, blood was collected from the wing vein in heparinized tubes from 2 turkeys per pen for plasma chemistry measurements. A separate blood sample was collected from the same turkeys in tubes containing K2EDTA for hematology measurements. Turkey performance was not affected by treatment during the starter 1 phase. Gain was greater (P = 0.024) and feed/gain lower (P = 0.030) for turkeys supplemented with Cr compared with controls during the starter 2 phase. Over the entire 84-d study turkeys supplemented with Cr had greater (P = 0.005) ADG and tended (P = 0.074) to gain more efficiently than controls. Gain (P = 0.180) and feed/gain (P = 0.511) of turkeys supplemented with 0.2 mg Cr/kg did not differ from those receiving 1.0 mg Cr/kg over the entire 84-d study. Feed intake was not affected by treatment. Body weights of turkeys supplemented with Cr were heavier (P = 0.005) than controls by d 84. Chromium supplementation did not affect hematological measurements and had minimal effect on plasma chemistry variables. Results of this study indicates that Cr Prop supplementation can improve turkey performance, and is safe when supplemented to turkey diets at 5x the minimal concentration that enhanced insulin sensitivity.

Chromium propionate in turkeys: effects on insulin sensitivity.

The objective of this study was to evaluate the effects of dietary chromium (Cr), as Cr propionate (Cr Prop), on measures of insulin sensitivity in turkeys. Plasma glucose and nonesterified fatty acid (NEFA), and liver glycogen concentrations were used as indicators of insulin sensitivity. One-day-old Nicholas Large White female poults (n = 336) were randomly assigned to dietary treatments consisting of 0 (control), 0.2, 0.4, or 0.6 mg supplemental Cr/kg diet. Each treatment consisted of 12 replicate cages with 7 turkeys per cage. Final BW were taken on d 34, and on d 35 two birds from each cage were sampled for plasma glucose and NEFA, and liver glycogen determination at the initiation (fed state) and termination (fasted state) of a 24-h fast. Following a 24-h fast, 2 turkeys per cage were refed (refed state) their treatment diet for 4 h, and then harvested. Feed/gain and ADG did not differ between control and Cr-supplemented turkeys over the 34-d study, but feed intake tended (P = 0.071) to be greater for controls than turkeys receiving 0.4 mg Cr/kg diet. Fed turkeys had greater plasma glucose (P = 0.002) and liver glycogen (P = 0.001) concentrations, and lower (P = 0.001) NEFA concentrations than fasted birds. Turkeys refed after fasting had greater (P = 0.001) plasma glucose and liver glycogen concentrations, and lower (P = 0.001) plasma NEFA levels than fed turkeys. Liver glycogen and plasma NEFA concentrations did not differ among control and Cr-supplemented birds in the fed, fasted, or refed state. Plasma glucose concentrations were not affected by treatment in fed or fasted turkeys. Turkeys supplemented with 0.2 or 0.4 mg Cr/kg and refed after fasting had lower (quadratic, P = 0.038) plasma glucose concentrations than controls. Plasma glucose concentrations in refed birds did not differ among Cr-supplemented turkeys. The lower plasma glucose concentration in Cr-supplemented turkeys following refeeding is consistent with Cr enhancing insulin sensitivity.

Research Note: Chromium propionate for turkeys: effect on tissue chromium concentrations and human food safety.

This study was conducted to determine the effect of supplementing turkey diets with chromium propionate (Cr Prop) on Cr concentrations in tissues consumed by humans. Nicholas White male day-old poults were used in this study. Treatments consisted of 0, 0.20, or 1.0 mg supplemental Cr/kg diet. Each treatment consisted of 8 replicate floor pens with 12 poults housed per pen. Diets were fed ad libitum for 84 d. At the end of the study, 2 turkeys per pen were euthanized and samples of liver, breast muscle, kidney, and skin with adhering fat were collected from a similar location in each bird for Cr analysis. Orthogonal contrasts were used to compare the 2 Cr supplemented treatments to the control (0 added Cr) and 0.20 mg Cr to 1.0 mg Cr/kg diet. When expressed on a DM or wet tissue basis, liver (P = 0.001) and muscle (P = 0.015) Cr concentrations were greater in turkeys supplemented with Cr compared with controls. Chromium concentrations in liver were also greater (P = 0.001) in turkeys supplemented with 1.0 mg Cr/kg than those receiving 0.20 mg Cr/kg. Concentrations of Cr in kidney and skin + fat were not affected by treatment. Considering the adequate intake of Cr established for humans, supplementation of Cr Prop at up to 1.0 mg Cr/kg diet would have minimal effect on total Cr intake by humans.

Performance and processing yield comparisons of Large White male turkeys by genetic lines, sources, and seasonal rearing.

Large White male turkey genetic lines (GL) comparison in performance and processing yields under the same conditions are rare in the literature. Two rearing experiments (EXP) were conducted to accomplish 2 objectives. The first objective was to test the effects of poult source and genetic lines on performance and processing yields. The second objective was to extract season and growth patterns when comparing both EXP common treatments. In EXP 1, male poults from 5 different sources were randomly assigned to 48 concrete: litter-covered floor pens. In EXP 2, male poults from 7 different genetic lines were randomly assigned to 48 concrete: litter-covered floor pens. For both EXP, the experimental design was a completely randomized block design with a one-factor arrangement. Both EXP were placed in the same house with the same management and nutrition in two separate seasons of the same year. Bird performance and carcass processing yield were analyzed in SAS 9.4 or JMP 15.1 in a mixed model. In EXP 1 no significant difference in BW or processing yield was observed. However, a similar GL from a commercial hatchery had an improved feed conversion ratio (FCR) over the same GL sourced directly from the genetic company hatchery. In EXP 2, statistical differences were observed in performance and breast meat yield depending on the GL. A season effect was observed when comparing the two EXP. Birds raised in the fall season had a 2 kg BW increase, on average, over their spring counterparts. This difference in BW can also be observed in a statistically higher breast meat yield by the birds raised in the fall over the ones raised in the spring. In conclusion, a comparison between GL resulted in effects due to genetic line, poult source, and rearing season on bird performance and carcass yield.

The effect of feed processing of novel unheated, low trypsin inhibitor soybeans on the performance of young female turkeys reared from hatch to 21 days of age.

The objective of this study was to evaluate the effects of dietary inclusion of a novel low trypsin inhibitor soybean (LTI) fed as mash or crumbled pellet form on the productive performance and digestibility in turkey poults from hatch to 21 d. A total of 336 Hybrid Converter turkey poults were allocated in groups of 7 to 6 treatments, each with 8 replicate cages. Treatments were arranged as a 3 × 2 factorial with inclusion level of the low trypsin-inhibitor soybean (0, 20, and 40% LTI) and feed form (mash and crumbled pellet). A single batch of feed was mixed for each inclusion level and divided into 2 aliquots: one remaining as mash and the other conditioned at 82°C for approximately 30 s, pelleted and then crumbled. On d 7, 14, and 21 posthatching, BW, and feed intake (FI) were recorded and BW gain (BWG) and feed conversion ratio (FCR) calculated. Excreta samples were collected from d 19 to 21 and pooled by cage. At d 21, intestines were excised, pancreas weights recorded (PRW), and ileal contents collected. There were no interactions (linear, P > 0.05) between LTI inclusion and feed form on BW, BWG, FI, or FCR at d 7 or 21. Increasing LTI resulted in a linear reduction in BW at 7, 14, and 21 d (P < 0.006). Poults fed crumbles were significantly heavier at d 21 than those fed mash feed (P < 0.027) with no interaction of LTI level with feed form. FCR was not significantly greater with increasing LTI. However, poults fed crumbles had a better, lower FCR that those fed mash feed from d 0 to 21 (P < 0.018). There was a significant interaction between feed form and LTI level at 14 d (P < 0.031), but not 7 or 21 d. Pancreatic hypertrophy (PRW) increased linearly with increasing LTI (P < 0.001) with a significant linear interaction with feed form (P < 0.001). Poults fed crumbles had less pancreatic hypertrophy. At 21 d of age, dietary fat digestibility (ALD, %) was linearly reduced with increasing LTI (P < 0.001). However, poults fed crumbles had significantly better fat absorption than poults fed mash (91.2 vs. 85.8%) (P < 0.001), and there was a significant linear interaction between feed form and LTI level (P < 0.001). AMEn was significantly better for the poults fed crumbles compared to mash (3228 vs. 3132 kcal/kg) (P < 0.001), and there was a significant linear interaction between feed form and LTI level (P < 0.001). Based on the results this trial, it is possible to include up to 20% unheated full fat LTI soybeans into poult starter diets after pelleting. Pelleting improves nutrient utilization, allowing for greater incorporation of the LTI soybean in the crumbled diet compared to the mash diet.

Effect of methionine chelated Zn and Mn and corn particle size on Large White male turkey live performance and carcass yields.

Most turkey research has been conducted with a regular corn particle size set through phase-feeding programs. This study's first objective was to determine the effect of increasing corn particle size through the feed phases on performance, processing yield, and feed milling energy usage in Large White commercial male turkey production. Zinc (Zn) and manganese (Mn) are essential microminerals for animals' healthy growth. The source in which these elements are supplied to the bird will determine their bioavailability, effect on bird growth, and subsequent environmental impact. This study's second objective was to measure both inorganic and chelated Zn and Mn sources on turkey performance, turkey carcass processing yields, and subsequent litter residues. Twelve hundred Nicolas Select male poults were randomly assigned to 48 concrete; litter-covered floor pens. The experimental design was a completely randomized block design with a 2 × 2 factorial arrangement of 2 sources of minerals (organic blend vs. inorganic) formulated to match breeder recommendations and 2 types of corn mean particle size (coarse corn [1,000-3,500 µm] vs. fine corn [276 µm]). The ASABE S319.4 standard was used to measure corn mean particle size. Bird performance, carcass processing yield, litter content of Zn and Mn, and pellet mill energy consumption were analyzed in SAS 9.4 in a mixed model. There was a reduction of pellet mill energy usage of 36% when coarse corn was added post-pelleting. Birds fed increasing coarse corn mean particle size were 250 g lighter on average in body weight (BW) than birds fed a constant control mean particle size. No difference was found in feed intake (FI) or feed conversion ratio (FCR). Birds fed methionine chelated Zn and Mn blended with inorganic mineral sources were 250 g heavier on average than birds fed only an inorganic source of minerals. In addition, feeding an organic blend of Zn and Mn resulted in greater breast meat yield. Litter from birds fed the control corn mean particle size, and inorganic minerals had a higher concentration of Zn in the litter but were not different when the chelated Zn/Mn were fed. In conclusion, increasing the corn mean particle size and adding it post pellet could save money during feed milling; however, birds might have a slightly lower BW. A combination of inorganic and chelated Zn and Mn may improve performance and increase total breast meat yields.

The effect of a heat-stable xylanase on digesta viscosity, apparent metabolizable energy and growth performance of broiler chicks fed a wheat-based diet.

Feed costs represent a significant portion of the cost of poultry production. This study, in 3 experiments, was conducted to evaluate the effectiveness of a heat-stable xylanase (XYL) as a dietary supplement and its effect on digesta viscosity, nitrogen-corrected apparent metabolizable energy (AMEn), and live performance in broiler chicks. Experiment 1: the objective was to determine the effects of the amount and type of enzyme supplementation on digesta viscosity, AMEn, and bird performance using 7 diets. The dietary treatments were: no supplementation (C), 5 levels of XYL (1 to 16 ppm), or supplementation with a carbohydrase cocktail (CC). Experiment 2: the objective was to determine the interaction of the dietary XYL and the energy content of the feed. There were 2 levels of XYL (0 and 20 ppm) and 3 dietary energy levels (2,770, 2,920, and 3,070 kcal/kg ME). Experiment 3: the objective was to determine the interaction of the dietary XYL and feed form. The treatments were: 5 levels of XYL (0 to 40 ppm) and 2 feed forms (mash and crumble). Broiler chicks were reared in battery cages to 21 d. Statistical analysis of the data was completed using Proc GLM of SAS (9.2) (SAS Institute, Cary, NC). In experiment 1, increasing XYL (0 to 16 ppm) resulted in a decrease in digesta viscosity and an increase in AMEn. The XYL included as low as 1 ppm resulted in a significant increase in AMEn which reached 5% with 16 ppm XYL. In contrast, increase in BWG (4%) above values with the basal diet was greatest with 1 ppm XYL. In experiment 2, the caloric content of the diet influenced the increase in AMEn with inclusion of XYL, 8% and 6% increases with 2,920 kcal/kg and 3,070 kcal/kg diets, respectively. Without addition of XYL, BWG was significantly lower when fed the diet with the highest energy content. In experiment 3, feed form x XYL influenced the effect of XYL on BWG. The BWG was greater when birds were fed the crumble diet with XYL vs when they were fed the mash feed with XYL. The xylanase proved effective for broilers to 21 d when fed the diets used herein with changes in digesta viscosity, increased dietary AMEn, and improved bird performance represented by either BW gain or FCR.

The effect of methyl-beta-cyclodextrin on DNA absorption and quality of posttransfected sperm.

Sperm can be selected as a natural vector for the production of transgenic animals. Methyl-beta-cyclodextrin (MBCD) removes cholesterol from the phospholipid membrane of sperm and improves the efficiency of DNA uptake by sperm. In experiment 1, fresh sperm was treated with various concentrations of MBCD. The direct effects of MBCD on sperm parameters were monitored. In experiment 2, different concentrations of MBCD (0, 1, 2, and 4 mmol) were assessed for the transfection of genetically exogenous construction to rooster sperm. Washed semen was divided into 5 equal groups for the incubation and transfection with a pcDNA3.1+/hG-CSF vector (exogenous DNA) as follows; Treatment I-Control (washed semen without DNA); Treatment II-Control (washed semen with DNA); Treatment III-(washed semen incubated with DNA and 1 mmol MBCD); Treatment IV-(washed semen incubated with DNA and 2 mmol MBCD); and Treatment V-(washed semen incubated with DNA and 4 mmol MBCD). We demonstrated that rooster spermatozoa spontaneously can uptake exogenous DNA; this was assessed using exogenous DNA amplification (sperm genomic DNA used as a template for PCR reaction) after DNase I treatment. In addition, total motility (TM), progressive motility (PM), velocity parameters [curvilinear velocity (VCL), straight linear velocity (VSL), sperm track straightness (STR), linearity (LIN)], membrane integrity (MI), and membrane functionality were posttransfectionally evaluated. The concentrations of 1 and 2 mmol MBCD significantly (P < 0.05) improved the motion characteristics and membrane integrity of fresh sperm. The presence of hG-CSF in rooster sperm was detected by PCR and based on sperm analyses MBCD (1 mmol) improved the percentage of motility (98.9 ± 0.81), membrane functionality (64 ± 1.64), and MI (76.2 ± 1.65) after transfection when compared with the other groups (P < 0.05). For the production of transgenic chicken, hens were inseminated (AI) by transfected sperm treated with 1 and 0 mmol MBCD. A PCR analysis of the blood samples and dead embryo tissues of chicks did not reveal the transgene integration.

Effect of pellet quality and biochar litter amendment on male turkey performance.

Bedding (litter) is essential to poultry performance and health and can have an environmental impact after use in the poultry facility such as a soil amendment or as an alternative energy source. Pine shavings are the most common bedding used for turkey production. However, the increase in its price and its increasing scarcity in some areas have created new research opportunities for reusing litter as bedding. Improvement in feed pellet quality has been reported to improve poultry performance. However, the reports for turkeys are limited and dated. This study's objective was to determine how the improvement of feed pellet quality and the use of biochar added to a combination of used turkey brooder house litter and Miscanthus grass as bedding affects turkey performance, small intestine morphology, and ammonia production. Nicolas Select (Aviagen Turkeys, Lewisburg, WV) male poults (816) were randomly assigned to 48 concrete litter floor pens on the day of hatch. The experiment used a completely randomized block design with a 2 × 4 factorial arrangement of treatments: 2 levels of fines in the feed and 4 bedding treatments. The bedding treatments were a constant level of used turkey brooder house litter combined with a varying combination of biochar and Miscanthus grass. Turkey's body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were determined. Differences in treatment means were considered to be statistically significant at P ≤ 0.05 using a mixed model in SAS 9.4. Turkeys fed the feed with improved pellet quality had a higher BW from 3 to 17 wk (17.0 ± 0.1 kg) than turkeys fed an increased abundance of fines (16.72 ± 0.1 kg). Turkeys fed feed with increased pellet quality had a lower FI (45.6 vs. 48.1 ± 0.4 kg) and improved FCR (2.20 vs. 2.31 ± 0.01) from 0 to 20 wk. Litter treatment with 20% biochar resulted in higher BW at 20 wk (20.91 ± 0.16 kg) because of increased BWG at 11 wk over the rest of the biochar levels (3.7 ± 0.1 kg). Strategies to reduce the abundance of fines in feed through feed formulation, feed manufacturing, feed transport, and in-house feed management should be considered to increase male turkeys' performance. There may be opportunities to use biochar as a litter amendment to improve turkey health and performance.

Effects of dietary alpha-lipoic acid supplementation on the seminal parameters and fertility potential in aging broiler breeder roosters.

High levels of polyunsaturated fatty acids in avian sperm cause more susceptibility to lipid peroxidation. Aging in roosters reduces the antioxidant capacity of sperm and thus fertility. The purpose of this study was to investigate the effects of different levels of alpha-lipoic acid (ALA) as a feed supplement to improve the semen quality and fertility parameters of aged broiler breeder roosters and identification of its most effective level. A total of forty-two roosters at 45 wk of age were randomly assigned to 7 treatments (0, 15, 40, 70, 95, 120, and 145 mg ALA/bird per day) for 8 wk. Semen parameters and body weight were assessed biweekly, and testosterone plasma levels were determined in the 8th wk of the experimental period. Artificial insemination was performed at the end of the experiment to evaluate the fertility potential. The dietary administration of ALA had no significant effects on body weight, semen volume, average path velocity, linearity, straightness, wobble, the amplitude of lateral head displacement, beat-cross frequency, sperm concentration, morphology, plasma testosterone level, fertility, or hatchability (P > 0.05). Alpha-lipoic acid supplementations resulted in a significant decrease in seminal malondialdehyde concentration and immotile (type D) sperms (P < 0.05). The total motility, progressive motility (types A + type B sperms), curvilinear velocity, straight-line velocity, viability, and membrane integrity of sperm improved with ALA dietary supplementations (P < 0.05). With increasing ALA levels, improvement in semen parameters had an incremental trend until the level of 95 mg ALA. Thus, 95 mg dietary ALA as an antioxidant supplement can improve semen quality of aging breeder roosters while higher doses resulted in no further improvement.

Effect of feed form, soybean meal protein content, and Rovabio Advance on poult live performance to 3 wk of age.

Based on research reports, feed characteristics can increase poult growth via several factors. Two rearing experiments (EXP) were conducted to test the effects of feed form and ingredient quality in turkey poults. Bird performance and the duodenum, jejunum, ileum, and cecum morphology were observed in both EXP. Poults were reared in battery cages (48 cages in EXP 1 and 72 cages in EXP 2). Four dietary treatments with differing feed form and function factors were evaluated in EXP 1. A completely randomized block design with a 2 × 2 × 2 factorial arrangement of treatments consisting of 2 levels of fines, 2 soybean meal (SBM) sources, and 2 levels of an enzyme cocktail (Rovabio Advance) was tested in EXP 2. Poult BW, BW gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were determined in both EXP. Apparent metabolizable energy corrected for nitrogen (AMEn) was determined in EXP 2. Differences were considered to be statistically significant at P ≤ 0.05. Feeding increased feed crumble particle size with fewer fines in the starter feed resulted in an increased BWG accompanied by an increased FI. Reduced feed fines reduced AMEn when the dietary enzyme cocktail was not present. The feed formulation with 60% CP SBM resulted in a lower FI and an improved FCR. The enzyme cocktail interacted synergistically with screening and fed SBM source factors on the AMEn and FCR. It was concluded that both the feed form and quality, as used in this study, affect poult performance.

Effects of stocking density on large white, commercial tom turkeys reared to 20 weeks of age: 1. growth and performance.

Industry standards for turkey stocking densities are variable and may not represent the more rapidly growing strains currently available. Therefore, a study was completed to evaluate 4 stocking densities: a nominal density (0.3525 m2/bird), 10% tighter density (0.3169 m2/bird), 10% looser density (0.3882 m2/bird), and 20% looser density (0.4238 m2/bird) on the effects on large white, commercial male turkeys with regard to performance from 5 to 20 wk of age. Brooding stocking density was fixed for all pens of birds with 60 birds per replicate pen at 0.46 m2/bird to 5 wk of age. Density treatments were applied from 5 to 20 wk by altering pen size with pen population held constant at 60 per pen. There were 4 pens of birds per density treatment. Birds were weighed individually at 0, 5, and 20 wk of age and performance parameters were calculated. There were no differences in bird performance at 5 wk, which was expected because stocking density was fixed. From 5 to 20 wk and at 20 wk, birds that were reared at the nominal standard (0.3525 m2/bird) and 10% tighter density (0.3169 m2/bird) had significantly lower body weight compared with the 10% looser density (0.3882 m2/bird) and 20% looser density (0.4238 m2/bird) (P = 0.03 and 0.01, respectfully). The feed conversion ratio (FCR) tended (P = 0.08) to be improved for birds reared at looser density. In addition, based on linear regression, as stocking density decreased (i.e., m2/bird increased), BW (P < 0.05) increased, and FCR (P = 0.10) tended to decrease (improve) at 20 wk. It was concluded that birds reared at looser density had improved performance.

Chromium propionate in broilers: human food and broiler safety.

Chromium propionate (Cr Prop) is approved by the U.S. Food and Drug Administration Center for Veterinary Medicine for supplementation to broiler diets up to 0.20 mg Cr/kg diet. A 49-D study was conducted to: 1) determine the safety of Cr Prop when supplemented at 2 and 10 times (×) the approved feeding level over the normal life span of broilers, and 2) determine the effects of supplementing Cr Prop on Cr concentrations of tissues consumed by humans. On day zero, 216 Ross 708 broilers were stratified by weight within sex and randomly assigned to treatments. Dietary treatments were 0 (control), 0.40, and 2.0 mg supplemental Cr/kg diet from Cr Prop. There were 6 replicate cages each of male and female broilers per treatment. At the end of the study blood was collected for determination of plasma biochemical measurements and tissue samples were collected for Cr analysis. Supplementing 0.40 mg Cr/kg diet (2×) did not adversely affect broiler performance, mortality, plasma biochemical measurements or Cr concentrations in breast muscle, skin with adhering fat, or liver. Chromium propionate supplemented at 2.0 mg Cr/kg (10×) did not affect Cr concentrations in breast muscle or skin with adhering fat, but increased (P < 0.05) liver Cr concentrations. Supplementing Cr Prop at 10× the approved feeding level decreased feed intake and gain in male but not female broilers from days 21 to 49. Results of this study support the safety of Cr Prop in broiler diets, and indicate that Cr Prop supplementation to broiler diets at 2 or 10× the approved feeding level does not present a human health concern.

Efficacy of feed additives to reduce the effect of naturally occurring mycotoxins fed to turkey hen poults reared to 6 weeks of age.

Corn with naturally occurring aflatoxin (AF), wheat with naturally occurring doxynivalenol (DON), and barley with naturally occurring zearalenone (ZEA) were used to make rations for feeding turkey hen poults to 6 weeks of age. Control rations with equal amounts of corn, wheat, and barley were also fed. The control rations did contain some DON while both sets of rations contained ZEA. Within each grain source, there were 4 treatments: the control ration plus 3 rations each with a different feed additive which were evaluated for the potential to lessen potential mycotoxin effects on bird performance and physiology. The additives were Biomin BioFix (2 lb/ton), Kemin Kallsil (4 lb/ton), and Nutriad UNIKE (3 lb/ton). The mycotoxin rations reduced poult body weight (2.31 vs. 2.08 ± 0.02 kg) and increased (worsened) poult feed conversion (1.47 vs. 1.51 ± 0.01) at 6 wk. Feeding the poults the mycotoxin feed also resulted in organ and physiological changes typical of feeding dietary aflatoxin although a combined effect of AF, DON, and ZEA which cannot be dismissed. The feed additives resulted in improved feed conversion to 6 wk in both grain treatment groups. The observed physiological effect of feeding the additives was to reduce relative gizzard weight for both groups and to lessen the increase in relative kidney weight for the birds fed the mycotoxin feed. In conclusion, the feed additives used in this study did alleviate the effect of dietary mycotoxins to some degree, especially with respect to feed conversion. Further studies of longer duration are warranted.

Gait parameters in four strains of turkeys and correlations with bone strength.

Locomotion problems in meat poultry have multifactorial etiology. A better understanding of normal gait and its influences on biomechanical aspects of leg bones among turkey genetic lines is important to prevent skeletal disorders and locomotion issues. The objective of this experiment was to determine the possible differences in gait kinetic and kinematic parameters of turkey strains and their effects on bone biomechanical properties. Four genetic lines, named A, B, C, and D, were obtained and raised in 48 floor pens with new pine shavings. Leg health issues were classified at 16 and 33 d of age. Fifteen turkeys from each strain with apparent normal legs and gait at 33 d of age were selected for gait analysis. These 15 turkeys were trained to walk on a pressure sensitive walkway and video was recorded to calculate articulation movements. These data also were analyzed to obtain kinetic and kinematic parameters of the gait cycle collected at 47, 84, 107, and 145 d of age. At 20 wk all turkeys were sacrificed, and legs were collected and frozen for analysis. Weights and morphologic measurements of the femur, tibia, and shank were recorded. Bone mineral density (BMD) and content (BMC) were obtained using DEXA. Femur and tibia strength were evaluated by a 4-point bending test and torsion test, respectively. Gait parameters changed as toms aged and some differences were observed among lines. Genetic lines differed on BMD, but not on BMC. Strain D had a higher BMD and smaller diaphyseal angle than strain C, characteristics that were correlated with stronger bones. Strain D also had the lowest incidence of leg problems while strain C had the highest. Furthermore, the D strain had a smaller vertical motion of the toe than strains C and B at 47 d and strain A at 145 d, indicating that the D strain had a more efficient gait. In summary, genetic strains differ significantly on gait parameters, which in turn impacts bone biomechanics.

Chromium propionate in broilers: effect on insulin sensitivity.

The objective of this study was to evaluate the effects of dietary chromium (Cr), as chromium propionate, on measures of insulin sensitivity. Liver and muscle glycogen, and plasma glucose and non-esterified fatty acid (NEFA) concentrations were used as indicators of insulin sensitivity. In total, 288 newly hatched male Ross broilers were divided into 4 dietary treatments consisting of 0 (control diet analyzed 0.43 to 0.45 mg Cr/kg), 0.2, 0.4, or 0.6 mg supplemental Cr/kg diet, resulting in 4 treatments with 9 replicate pens per treatment containing eight birds per pen. At d 21, 2 birds per cage were removed based on the greatest deviation from pen mean BW, resulting in each pen containing 6 birds for the final analyses. Final BW were taken on d 40, and on d 42 two birds from each pen were sampled for plasma NEFA, glucose, and muscle and liver glycogen determination at the initiation and termination of a 22 h fast. The remaining 2 fasted birds were sampled after a 30 min refeeding period. No differences were observed in feed intake, BW gain, or feed efficiency on d 21 or d 40. Liver glycogen tended (P=0.10) to be greater in Cr-supplemented chicks in the fed state, and muscle glycogen concentrations tended (P=0.07) to be greater in Cr-supplemented chicks compared with controls following fasting and refeeding. Plasma glucose concentrations were not affected by dietary Cr in the fed, fasted, or refed state. Plasma NEFA levels were not affected by treatment in fed or fasted birds. However, plasma NEFA concentrations were lower (P<0.01) in chicks supplemented with Cr than in controls following fasting and refeeding, suggesting that Cr increased insulin sensitivity. No differences were detected among birds supplemented with 0.2 or 0.4 mg Cr/kg, and among those receiving 0.4 or 0.6 mg Cr/kg. Results of this study indicate that Cr propionate supplementation of a control diet containing 0.43 to 0.45 mg Cr/kg enhanced insulin sensitivity.

Effect of direct-fed microbials on performance and Clostridium perfringens colonization of turkey poults.

Clostridium perfringens is recognized as an enteric pathogen in humans, domestic animals, and livestock. This organism is associated with necrotic enteritis, gangrenous dermatitis, clostridial dermatitis (turkeys), and gizzard erosions in poultry. This study was conducted to evaluate the effectiveness of a direct-fed microbial (DFM), Primalac (Star Labs, Clarksdale, MO), in preventing intestinal colonization of turkey poults with C. perfringens. One-day-old turkey poults (n = 128) were randomly divided into 4 treatments with 4 replicates (8 birds/pen). Treatments were as follows: 1) basal diet without DFM (C); 2) basal diet supplemented with Primalac (1.5 kg/ton; PM); 3) basal diet with poults gavaged with C. perfringens (CCP); and 4) basal diet supplemented with Primalac and poults gavaged with C. perfringens (PMCP). Feed and water were provided ad libitum throughout the trials, and birds were inoculated with C. perfringens (10(8)cfu/mL) on d 3 and 7. On d 21, 2 birds/pen were killed, spleen and bursa of Fabricius were collected and weighed, and cecal contents were used for C. perfringens enumeration. Feed consumption, BW, and feed conversion were calculated throughout the trial (weekly and cumulatively). Data were analyzed using GLM of SAS (SAS Institute, Cary, NC; P < 0.05). Among the inoculated groups, birds fed the DFM-supplemented diet had significantly lower cecal C. perfringens counts than the birds fed the diet without the DFM. The C. perfringens (log(10) cfu/g) in ceca were as follows: C, 5.88; CCP, 7.26; PM, 5.35; PMCP, 6.19 ± 0.36. No differences were observed for BW (814 ± 11 g), feed conversion (1.33 ± 0.03), organ weights, or relative organ weights. Further studies are needed to fully ascertain the potential of using DFM to reduce the numbers of C. perfringens in the gastrointestinal tract of turkey poults.

Effect of a direct-fed microbial (Primalac) on structure and ultrastructure of small intestine in turkey poults.

The effects of dietary supplementation of the direct-fed microbial (DFM) Primalac in mash or crumbled feed on histological and ultrastructural changes of intestinal mucosa was determined in 2 populations of poults; 1 with and 1 without a Salmonella spp. challenge. Three hundred thirty-six 1-d-old female Large White turkey poults were randomly distributed into 8 treatment groups with 6 replicates of 7 poults in each pen. The poults were placed on 1 of 4 dietary treatments in a 2 x 2 x 2 factorial arrangement (mash or crumble feed, with or without DFM, not-challenged or challenged at 3 d of age). The DFM groups were fed a Primalac-supplemented diet from d 1 until the last day of the experiment (d 21). At 3 d of age, 50% of the poults were challenged with 1 mL of 10(10) cfu/ mL of Salmonella spp. (Salmonella enterica serovar Typhimurium, Salmonella Heidelberg, and Salmonella Kentucky) by oral gavage. The inoculated poults were housed in a separate room from nonchallenged controls. Feed and water were provided ad libitum for all birds. At d 21, 1 poult per pen (total of 6 poults per treatment) was randomly selected and killed humanely by cervical dislocation. After necropsy, the small intestine was removed, and tissue samples from duodenum, jejunum, and ileum were taken for light and electron microscopic evaluation. The DFM birds showed increased goblet cell (GC) numbers, total GC area, GC mean size, mucosal thickness, and a greater number of segmented filamentous bacteria compared with controls. Changes in intestinal morphology as observed in this study support the concept that poultry gut health and function, and ultimately bird performance, can be improved by dietary supplementation with DFM products such as Primalac as used in this study.

Organic trace minerals and 25-hydroxycholecalciferol affect performance characteristics, leg abnormalities, and biomechanical properties of leg bones of turkeys.

Leg problems and resulting mortality can exceed 1% per week in turkey toms starting at approximately 15 wk of age. Dietary supplementation of organic trace minerals (MIN) and 25-hydroxycholecalciferol (HyD) may improve performance, decrease incidence of leg abnormalities, and increase bone strength. Nicholas 85X700 toms were assigned to 4 treatments consisting of a factorial arrangement of 2 concentrations of MIN (0 and 0.1% of Mintrex P(Se), which adds 40, 40, 20, and 0.3 mg/kg of Zn, Mn, Cu, and Se, respectively) and 2 concentrations of HyD (0 and 92 microg/kg of HyD). Diets were formulated to be equal in nutrient content and fed ad libitum as 8 feed phases. Feed intake and BW were measured at 6, 12, 15, 17, and 20 wk of age. Valgus, varus, and shaky leg defects were determined at 12, 15, 17, and 20 wk of age. Tibia and femur biomechanical properties were evaluated by torsion and bending tests at 17 wk of age. There were no treatment effects on BW. Only MIN significantly improved feed conversion ratio through to 20 wk of age. Cumulative mortality at 3 wk of age was greater among the MIN birds, but it was lower by 20 wk (P = 0.085). The MIN decreased the incidence of varus defects at 17 wk of age; shaky leg at 12, 15, and 17 wk of age; and valgus defects at 15, 17, and 20 wk of age. There were no MIN x HyD interaction effects on individual gait problems. Maximum load and the bending stress required for tibias to break in a 4-point assay were increased with MIN supplementation, especially when HyD was also added. Maximum shear stress at failure of femoral bones in a torsion assay was increased by supplementation with both MIN and HyD together. Dietary supplementation of MIN and HyD may improve biomechanical properties of bones. Dietary MIN supplementation may improve feed conversion of turkeys, likely by decreasing leg problems.

Effects of incubator temperature and oxygen concentration during the plateau stage of oxygen consumption on Turkey embryo long bone development.

Temperature (TEM) and O(2) concentrations during the plateau stage of oxygen consumption are known to affect yolk utilization, tissue development, and thyroid metabolism in turkey embryos. Three experiments were conducted to evaluate these incubation effects on long bone development. Fertile eggs of Nicholas turkeys were used. In each trial, standard incubation conditions were used to 24 d, when the eggs containing viable embryos were randomly divided into 4 groups. Four experimental cabinets provided 4 TEM (36, 37, 38, or 39 degrees C) or 4 O(2) concentrations (17, 19, 21, or 23% O(2)). In the third experiment, 2 temperatures (36 and 39 degrees C) and 2 O(2) concentrations (17 and 23%) were evaluated in a 2 x 2 factorial design. Body and residual yolk weights were obtained. Both legs were dissected, and shanks, femur, and tibia weights, length, and thickness were recorded. Relative asymmetry of each leg section was calculated. Chondrocyte density was evaluated in slides stained with hematoxylin and eosin. Immunofluorescence was used to evaluate the presence of collagen type X and transforming growth factor beta. Hot TEM caused reduction of tibia weights and increase of shank weight when compared with cool TEM. The lengths of femur, tibia, and shanks were reduced by 39 degrees C. The relative asymmetry of leg weights were increased at 38 and 39 degrees C. Poult body and part weights were not affected by O(2) concentrations, but poults on 23% O(2) had bigger shanks and heavier tibias than the ones on 17% O(2). High TEM depressed the fluorescence of collagen type X and transforming growth factor beta. The O(2) concentrations did not consistently affect the immunofluorescence of these proteins. The chondrocyte density was affected by TEM and O(2) in resting and hypertrophic zones. In the third experiment, high TEM depressed BW, leg muscle weights, and shank length. Low O(2) reduced tibia and shanks as a proportion of the whole body. We concluded that incubation conditions affect long bone development in turkeys.