Browsing by Subject "broilers"
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Item Continuous multi-phase feeding of broiler chickens(Texas A&M University, 2005-02-17) NasrilContinuous multi-phase feeding of broiler chickens was evaluated to optimize broiler nutrition and minimize environmental impact related to excess nitrogen in poultry manure. Four experiments were conducted. Experiments 1 and 2 studied effects of continuous multi-phase feeding during a 3-week starting period using battery brooders while experiments 3 and 4 evaluated multi-phase feeding during a traditional 7-week growing period using both battery brooders and floor pens. In the first and second experiments, the nutrient content of the multi-phase diets was changed every 24 hours in comparison to single-phase feeding. Results indicated that during the starter period, continuous multi-phase feeding had no significant influence on feed consumption, daily gain, feed to gain ratio or fecal nitrogen. In the third and fourth experiments, a four phase industry type broiler feeding program was compared to intensive multi-phase feeding programs created by linearly blending three different diets based on typical industry nutrient values and a commercial nutrient modeling computer program (EFG Natal?). In both intensive multi-phase feeding programs, the diets were changed every three days over a 7-week growth period. Broilers in experiment 3 were raised in Petersime battery brooders to primarily access nitrogen balance while birds in experiment 4 were raised in a floor pen on pine shaving litter to resemble commercial broiler production. The results indicated that intensive multi-phase feeding improved body weight gain and feed to gain ratio only in weeks 5 and 6 but not during the overall 7-week period. Nitrogen excretion and nitrogen retention were unaffected by the intensive multi-phase feeding systems. Economic analysis indicated that intensive multi-phase feeding programs could potentially lower feed costs per kilogram of gain. However, the high cost of implementing a continuous multi-phase feeding system may not justify the relatively small gain in lower feed cost per kilogram of gain. In conclusion, continuous multi-phase feeding of broiler chickens using corn-soy diets does not appear to be justified by either increased performance or reduced nitrogen excretion.Item Detecting Aflatoxicosis in Broilers in the Evaluation of Clay-based, Toxin-binding Feed Additives(2014-11-17) Fowler, Justin CaseThe objectives of this research were to evaluate common biological measures of aflatoxicosis in broilers (such as growth rate and relative organ weights) along with variables such as hepatic gene expression and aflatoxin residues in the liver, pursuant to identifying a more sensitive biological assay that will allow researchers to conduct three-week broiler trials at aflatoxin concentrations <1000 ppb, prior to significant changes in the growth rate or relative organ weights. This will help us both better understand how aflatoxicosis presents in broilers, as well as help us evaluate the efficacy of clay-based binders for their ability to ameliorate aflatoxicosis under experimental conditions. In the first study, a recently mined calcium bentonite clay (TX4) was evaluated against Novasil?. Both clays appeared able to sequester aflatoxin, and overall TX4 appeared capable of ameliorating aflatoxicosis comparable to Novasil?. In the second study, growth and relative organ weight data were compared with the gene expression of hepatic enzymes known to detoxify aflatoxin B1 in broilers that had consumed a wide range of aflatoxin concentrations. When gene expression data from liver samples were analyzed, the genotypic effect of aflatoxin on the CYP1A1 and CYP2H1 isoforms simply mirrored the phenotypic effects seen in the growth and relative organ weights, suggesting that this variable was not any more sensitive than the more traditional ones. The third study evaluated the TX4 clay when in diets containing <1000 ppb aflatoxin. Although weight gain was unaffected by aflatoxin at these lower levels (after three weeks on treatment diets, body weights between the 0 ppb treatment and the 700 ppb treatment only varied by 4%), there were negative effects on feed conversion and productivity index and there was an increase in the relative weights of the liver and kidney. The inclusion of TX4 to the treatment diets did not offer any amelioration from the main effects of aflatoxin. Finally, a study was conducted to evaluate the effects of TX4 clay when using residues of aflatoxin B1 in the liver as the primary variable of interest. Results after one week on treatment diets showed that TX4 was effective at reducing the accumulation of aflatoxin B1 residues in liver. However, after the first week, liver residue data were not any more sensitive in evaluating aflatoxin or clay effects when compared to the ?traditional? measures of growth performance and organ weights. Also, these results indicate that the clearance time required to remove aflatoxin residues from the liver is less than one week on a clean corn diet. Based on these evaluations, attempts to characterize a more sensitive, sentinel-type response to aflatoxin exposure in broilers were not any more successful at evaluating aflatoxicosis than was the common bioassay measures such as growth rate and relative organ weights. These studies (by contaminating corn with aflatoxigenic species of Aspergillus) were able to find significant main effects for aflatoxin at lower concentrations (?1000 ppb) than had been previously reported by the studies that included inoculated rice.Item Effects of Microbial Litter Amendments on Broiler Performance, Litter Quality and Ammonia Production(2011-02-22) Hinkle, MatthewThe reuse of litter in broiler production can lead to litter pathogen buildup and high levels of ammonia in broiler housing, thus resulting in poor broiler performance. This study evaluated the effects of two microbial litter amendments on litter characteristics, ammonia production and broiler performance. Experiment one, consisting of three trials, utilized eight pens approximately 3 x 3.2 m (10 x 10.5 ft) to rear broilers to 49 d of age. Experiment two, consisting of one trial, utilized twelve 1.8 x 3.7 m (6 x 12 ft) pens to rear broilers to 42 d of age. Used litter was obtained from separate commercial broiler farms for each experiment and placed into the pens at an average depth of 11 cm (4.3 in). Feed consumption and mortality were recorded for each pen for each trial. Ammonia production was measured by placing an enclosed chamber over the litter and measuring the headspace ammonia concentration after 20 minutes for both experiments. Experiment one also utilized a two minute ammonia flux technique. Ammonia measurements were taken at the time of litter treatment, at chick placement, and once per week for the remainder of the grow-out. Litter samples were collected at the same time and location as ammonia measurements. At the end of all trials, caked litter was removed from each pen, weighed and sampled. Litter and cake samples were analyzed for total aerobic and anaerobic microbial counts in experiment 1. Experiment 2 analyzed aerobic litter samples only. Paw scores were also recorded at the end of each trial for all birds using a 3-point scale. Data was subjected to ANOVA using the GLM procedure with means deemed significantly different at P < 0.05. Statistical differences were seen sparingly in different parameters in both experiments; however these differences were random in their distribution and showed no trend. Final results indicated that the microbial litter amendments had no effect on broiler performance, litter characteristics or ammonia production.Item Evaluation of Exogenous Enzymes Targeting Non-starch Polysaccharides in Reduced Energy Diets on Broiler Growth Performance and Processing Parameters(2013-12-04) Klein, Joseph ThomasMultiple experiments were conducted to investigate the inclusion of a cocktail NSPase and ?-mannanase, separately and in combination, in reduced energy diets on broiler growth performance and processing yield. Each experiment contained a positive control (PC), negative control (NC) diet (-132 kcal/kg AME), and the inclusion of enzymes in the NC to evaluate enzyme effectiveness. The reduction in energy negatively impacted performance and processing parameters in all experiments. The inclusion of NSPase negated the negative effects of energy reduction in experiment 1. Experiment 2 evaluated increased pelleting temperature on NSPase activity. Body weight (BW) was increased (P<0.05) with the inclusion of NSPase pelleted at 80, 85, and 90 C throughout the experiment compared to NC; however, the treatment pelleted at 80 C outperformed the other NSPase pelleted treatments. The inclusion of NSPase pelleted at 80 C reduced (P<0.05) feed conversion ratio (FCR) compared to the NC throughout the experiment. At the conclusion of the trial, NSPase inclusion pelleted at 85 and 90 C yielded FCR similar to PC. The experimental design of experiment 3 and 4 included five dietary treatments including a PC, NC, NC supplemented with ?-mannanase, NSPase, and ?-mannanase/NSPase. Performance parameters were evaluated on d 14, 28, 42, and 47 and a subset of broilers were processed on day 48. Increases (P<0.05) in BW were observed with the inclusion of NSPase and ?-mannanase/ NSPase on day 14 and with all treatment groups on day 28. An additive effect was observed with reduced FCR through day 28 with the combination of ?-mannanase/ NSPase. In experiment 4, performance was evaluated on days 14, 27, 35, and 41 and carcass yields determined on day 42. Increases in day 14 BW were observed with the inclusion of the NSPase alone and ?-mannanase/NSPase to reach a similar weight as the PC. Inclusion of ?-mannanase/NSPase increased (P<0.05) BW compared to the NC. Inclusion of the NSPase reduced (P<0.05) cumulative FCR through 41 days of age. Inclusion of ?-mannanase/NSPase resulted in reduced (P<0.05) FCR in the finisher phase and cumulatively throughout the trial to levels of the PC. The combination of ?-mannanase/NSPase did increase (P<0.05) WOG weight similar to observations in BW. These data confirm that enzyme supplementation in low energy diets improve performance and indicate that additive effects of a combination of enzymes could potentially be a cost saving strategy for producers.Item Preventive Measures to Control Clostridial Outbreaks of Gangrenous Dermatitis in Commercial Broiler Operations(2011-08-08) Waneck, Casey R.Gangrenous dermatitis (GD) has become a major health problem among broiler flocks in the United States, resulting in high mortality, carcass condemnations, and trimmed parts. There are large economic losses due to GD. Clostridium septicum, Clostridium perfringens type A, and Staphylococcus aureus are the etiologic agents associated with GD. Gangrenous dermatitis has been associated with birds that have a compromised immune system. It is known that the gastrointestinal (GI) tract plays a crucial role in animal health and performance. The development of a healthy normal microflora in the GI tract benefits the host by improved resistance to pathogens. Our hypothesis is the application of commercial disinfectants, probiotics, vitamins, acidifiers, and windrowing technologies will reduce Clostridium levels in poultry operations. The objective of the first study was to administer probiotics to commercial broilers on three farms periodically throughout the grow-out cycle to conclude if bird health and performance was improved. The objective of the second study was to use commercial disinfectants, vitamins, acidifiers, and windrowing technologies on three farms in multiple houses and determine their effects on broiler production parameters. During grow-out, standard production practices were followed in all experiments and standard production parameters were measured. On all three farms in this study, the probiotic-treated houses had no mortality due to GD and an increase (P