A. J. Pescatore

Ammonia Emissions from Twelve U.S. Broiler Chicken Houses

Twelve commercial broiler houses in the U.S. were each monitored for at least thirteen 48 h periods over the course of one year to obtain ammonia emission data. Paired repetition of houses on four farms represents current construction with variety in litter management (built-up or new litter each flock) and climate conditions (cold or mixed-humid). Ammonia concentration was determined using portable electrochemical sensors incorporating a fresh air purge cycle. Ventilation rate was determined via in-situ measurement of fan capacity, fan on-off times, and house static pressure difference. There were seasonal trends in exhaust ammonia concentration (highest in cold weather) and ventilation rates (highest in warm weather) but not for emission rate. Flocks with at least three monitoring periods (13 of 22 flocks) demonstrated similar emission rates at a given bird age among the four study farms and across the seasons. An analysis of emissions from all houses on the three farms using built-up litter resulted in predicted regression slopes of 0.028, 0.034, and 0.038 g NH3 bird-1 d-1 per day of age; the fourth farm, managed with new litter, had the lowest emission rate at 0.024 g NH3 bird-1 d-1. The intercept of these composite relationships was influenced by litter conditions, with flocks on new litter having essentially no emissions for about six days while built-up litter flocks had emissions starting at flock placement. Data from all four farms and all flocks provided a regression slope of 0.031(±0.001 std error) g NH3 bird-1 d-1 per day of age. Emission rate per animal unit for built-up litter flocks indicated very high emissions for the youngest birds (under 14 days of age), after which time the emissions decreased exponentially and were then relatively steady for the balance of the flock cycle.

Effect of enzyme supplementation and acidification of diets on nutrient digestibility and growth performance of broiler chicks

Two experiments were conducted to examine the effects of alpha-galactosidase supplementation and acidification of diets on nutrient digestibility and growth performance of broiler chicks. In experiment 1, dietary treatments consisted of feeding a low-energy basal diet (2.74 Mcal of ME/kg) alone, the basal diet supplemented with 1,724 units of alpha-galactosidase per kg, the basal diet supplemented with 2% citric acid, or the basal diet supplemented with both. alpha-Galactosidase significantly increased feed intake, weight gain, AME(n) of the diets, and retention of CP and neutral detergent fiber (NDF) (P < 0.05). Citric acid significantly increased the retention of DM, CP, and NDF, but decreased feed intake and weight gain. The greatest values for DM and NDF retention and for AME(n) were obtained with the combination of alpha-galactosidase plus citric acid. In experiment 2, chicks were fed diets with 2 levels of energy (2.74 or 3.11 Mcal/kg), 2 levels of citric acid (0 or 1.5%), and 2 levels of alpha-galactosidase (0 or 1,724 units/kg) in a 2 x 2 x 2 factorial arrangement of treatments. alpha-Galactosidase significantly increased the reducing sugar concentration in the crop content, whereas citric acid decreased the pH and increased the reducing sugar concentration in the crop content. Citric acid decreased the gain to feed ratio in the absence but not in the presence of alpha-galactosidase. The data from these studies indicate that acidification of diet improves the efficacy of alpha-galactosidase.

Effects of feeding different forms of zinc and copper on the performance and tissue mineral content of chicks

A study was conducted to investigate the effects of feeding inorganic or organic Zn and Cu on the performance and tissue mineral content of chicks. A corn-soybean meal diet without Cu and Zn supplementation, containing 31 mg of Zn/kg of diet and 6.6 mg of Cu/kg of diet, was used as a basal diet. Organic Zn (a chelated Zn proteinate) and organic Cu (a chelated Cu proteinate) were used as organic sources for comparison with inorganic reagent-grade sulfates. Supplements provided 20 mg/kg of Zn and 8 mg/kg of Cu. A 3x3 factorial arrangement of treatments consisting of feeding the basal diet with 3 supplements (none, sulfate, or organic) of Cu and of Zn was used. Ten groups of 6 one-day-old male broilers were assigned to each of 9 dietary treatments. Tap water and feed were supplied on an ad libitum basis during the 3-wk trial. The Zn and Cu content in the mucosa of the duodenum of the chick was determined. Dietary supplementation of Zn increased (P<0.01) weight gain, feed intake, and G:F of chicks. The G:F for chicks fed both inorganic sources of Zn and Cu was lower (P<0.01) than that for chicks fed only the inorganic source of Zn. Dietary inclusion of Zn increased (P<0.01) tibia and plasma Zn content. The tibia Zn content for chicks fed organic Zn was higher (P<0.01) than that for chicks fed inorganic Zn. Liver Cu content was decreased (P<0.05) by dietary inclusion of Zn. The Zn and Cu contents in the mucosa of chicks fed the organic source were higher (P<0.01) than those of chicks fed the control diet. The feed conversion data suggest that the antagonism between Zn and Cu occurred when the inorganic forms, but not organic forms, of these 2 minerals were included in a chick diet.

Effects of organic zinc and phytase supplementation in a maize–soybean meal diet on the performance and tissue zinc content of broiler chicks

1. The purpose of this study was to investigate the effects of Bioplex Zn® (a chelated zinc proteinate) and phytase supplementation in a maize–soybean meal diet on the performance and tissue zinc (Zn) content of broiler chicks. Treatment structure consisted of a 2 × 6 factorial arrangement with two inclusions of phytase (0 or 500 PU/kg) and 6 of Bioplex Zn® providing 0, 2, 4, 8, 16 and 32 mg Zn/kg diet. A total of 864 chicks were randomly assigned to each of 12 dietary treatments with 6 replicate cages of 12 chicks. 2. Dietary inclusion of phytase increased feed intake, weight gain, plasma Zn content, tibia Zn content, tibia and ash weight. 3. Dietary supplementation of Bioplex Zn® linearly increased feed intake, weight gain, gain to feed ratio, plasma Zn concentration, liver Zn concentration, tibia Zn content, tibia and ash weight. 4. An interactive effect of phytase and Bioplex Zn® on feed intake, weight gain, tibia Zn concentration and tibia ash weight was found. 5. One slope, straight broken-line analysis of weight gain regressed on the supplemental Zn level provided as Bioplex Zn® indicated that 12 mg/kg supplemental Zn without phytase and 7·4 mg/kg supplemental Zn with phytase were required for the optimal weight gain of chicks.

Effects of yeast cell wall-derived mannan-oligosaccharides on jejunal gene expression in young broiler chickens

The use of mannan-oligosaccharides (MOS) as alternatives to antibiotic growth promoters (AGP) has gained in popularity in recent years due to regulatory restrictions of using AGP in food animal production. Benefits of MOS usage include improvement on animal performance, feed efficiency, and gastrointestinal health. The molecular mechanisms of these functions however are not clear. The goal of the current study was to use a transcriptomics approach to investigate the effects of MOS on the intestinal gene expression profile of young broilers and characterize biological gene pathways responsible for the actions of MOS. One hundred and twenty 1-d-old Cobb 500 broiler chicks were randomly divided into 2 groups and were fed either a standard wheat-soybean meal-based (control) diet or the same diet supplemented with 2.2 g/kg of MOS (Bio-Mos, Alltech, Nicholasville, KY) for 3 wk, followed by jejunal gene expression profiling analysis using chicken-specific Affymetrix microarrays. Results indicated that a total of 672 genes were differentially expressed (P < 0.01 and fold change >1.2) in the jejunum by MOS supplementation. Association analysis indicated that differentially expressed genes are involved in diverse biological functions including energy production, cell death, and protein translation. Expression of 77 protein synthesis-related genes was differentially regulated by MOS in the jejunum. Further pathway analysis indicated that 15 genes related to oxidative phosphorylation were upregulated in the jejunum, and expression of genes important in cellular stress response, such as peroxiredoxin 1, superoxide dismutase 1, and thioredoxin, were also increased by MOS. Differential expression of genes associated with cellular immune processes, including lysozyme, lumican, β 2-microglobin, apolipoprotein A-1, and fibronectin 1, were also observed in MOS-fed broilers. In summary, this study systematically identified biological functions and gene pathways that are important in mediating the biological effects of MOS in broilers.

Effects of feeding different concentration and forms of zinc on the performance and tissue mineral status of broiler chicks

1. Two studies were conducted to investigate the effect of feeding different concentration and forms of zinc (Zn) on the performance and tibia Zn status of broiler chicks. 2. In Experiment 1, chicks fed on the control or the diet supplemented with 12 mg of Zn as sulphate had lower feed intake, weight gain and tibia Zn content than other treatment groups. Chicks given 12 and 24 mg of organic Zn in starter and grower phases, respectively, had the same performance and tibia Zn content as those fed 40 mg of Zn as sulphate and the same performance but higher tibia Zn content than those given 12 mg of Zn as organic over the 42 d. 3. In Experiment 2, chicks given 24 mg organic Zn had greater weight gain than chicks fed on the other treatment diets in the starter period. Chicks fed on the control diet had lower tibia Zn content than chicks fed other treatment diets. Chicks given 80 mg Zn as sulphate had higher tibia Zn content than chicks fed the other treatment diets except those given 40 mg of Zn as sulphate. 4. The results from these trials indicate that feeding lower concentration of Zn as organic form may better promote the growth performance of broiler chicks.

Effects of organic and inorganic dietary selenium supplementation on gene expression profiles in oviduct tissue from broiler-breeder hens

Selenium (Se) is an essential component of at least 25 selenoproteins involved in a multitude of physiological functions, including reproduction. However, relatively little is known about the mechanisms by which Se exerts its physiological effects in reproductive tissue. The objective of this study was to compare the effect of long-term inorganic Se (sodium selenite, SS) and organic yeast-derived Se (Sel-Plex(®), SP) supplementations on tissue Se content and gene expression patterns in the oviduct of broiler-breeder hens. Hens were randomly assigned at 6 weeks of age to one of the three treatments: basal semi-purified diet (control), basal diet+0.3 ppm Se as SP or basal diet+0.3 ppm Se as SS. At 49 weeks, oviduct tissue from hens randomly selected from each treatment (n=7) was analyzed for Se content and gene expression profiles using the Affymetrix Chicken genome array. Gene expression data were evaluated using GeneSpring GX 10.0 (Silicon Genetics, Redwood, CA) and Ingenuity Pathways Analysis software (Ingenuity Systems, Redwood City, CA). Oviduct Se concentration was greater with Se supplementation compared with the control (P≤0.05) but did not differ between SS- and SP-supplemented groups. Gene expression analysis revealed that the quantity of gene transcripts associated with energy production and protein translation were greater in the oviduct with SP but not SS supplementation. Targets up-regulated by SP, but not SS, included genes encoding several subunits of the mitochondrial respiratory complexes, ubiquinone production and ribosomal subunits. SS hens showed a decrease in transcripts of genes involved in respiratory complexes, ATP synthesis and protein translation and metabolism in oviduct relative to control hens. In this study, although tissue Se concentrations did not differ between hens fed SS- and SP-supplemented diets, expression patterns of genes involved in energy production and protein synthesis pathways differed between treatments. These variations may partially explain the differences in reproductive performance reported in hens fed different forms of Se.

Effect of zinc imprinting and replacing inorganic zinc with organic zinc on early performance of broiler chicks

&NA; The goal of this study was to determine the effects of feeding a zinc (Zn) deficient diet to broiler chicks for 96 h post‐hatch followed by feeding diets with different Zn sources and supplemental levels (5 to 21 d) on the growth performance, tissue, and excreta Zn content. At the start of the study, four hundred 20‐day‐old male broiler chicks were divided into two groups. One group was fed a corn soybean meal based diet containing 25 mg of Zn/kg (imprinting diet, ID). The second group was fed the basal diet supplemented with 40 mg of Zn/kg from Zn oxide (ZnO) (non‐imprinting diet, NID). Both groups were fed these diets for 96 h. At d 5, chicks from each group were randomly assigned to the dietary treatments consisting of the basal diet alone or the basal diet supplemented with 8 or 40 mg/kg Zn as ZnO or Zn proteinate. Main effects of post‐hatch Zn ID were observed on feed intake and G:F. ID decreased (P < 0.05) feed intake and improved (P < 0.05) the gain to feed ratio (G:F) of 14 and 21 d old chicks compared to G:F of chicks fed NID. Additionally, G:F for 14 and 21 d was improved (P < 0.05) by interaction of Zn source × level. Furthermore, at d 21 chicks fed the ID had a lower (P < 0.05) Zn content in the tibia ash and excreta, and a higher (P < 0.05) Zn content in the pancreas tissue compared to chicks fed NID. These results suggest that Zn imprinting can affect body Zn stores and early performance.

Barley β-glucan in poultry diets.

There has been an increased interest in the use of immunomodulators as substitutes for antibiotics in food animal production. Beta-glucans from yeast and fungi may be ideal substitutes because of their positive effects on the avian immune system without adversely affecting poultry performance. Barley β-glucans, however, have not shown this potential due to the adverse effects dietary inclusion of barley has on poultry performance.

Assessing Air Leakage in Commercial Broiler Houses

The design and operation of broiler house ventilation are directly related to the air inlet characteristics. Air leakage affects the air distribution and mixing inside the houses causing negative effects on the inside air quality and environmental control. A common method of evaluating broiler house tightness is to entirely close the house, turn on a single 1.2m (48-inch) exhaust fan, and record the static pressure. A new procedure to assess broiler house tightness was developed. Fourteen air leakage curves (of the form **this equation is following the Introduction below***) from fourteen different broiler houses (located in the state of Kentucky) were developed by recording static pressure inside the house when different calibrated fans were turned on. A Fan Assessment Numeration System (FANS) was used for exhaust fan calibration. The air flow exponent (n) ranged from 0.35 to 0.74 (standard error varying from 0.02 to 0.12). The flow coefficient k (m3s-1Pa-n) ranged from 0.55 to 3.55 (standard error varying from 0.1 to 0.45). The results show substantial variability among Kentucky broiler houses.