Browsing by Subject "Broiler"
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Item Enhancement of Growth Performance and Bone Mineralization in Market Broilers through Dietary Enzymes(2012-02-14) Coppedge, Jacob RyanFour research experiments were conducted to evaluate the influence of dietary enzyme inclusion (phytase and NSPase) on broiler performance parameters, processing yields, and bone mineralization. In Experiment 1, a 35-day grow out trial was conducted to investigate the effect of three commercially available phytase enzymes on growth performance and bone mineralization in phosphorus deficient corn/soy based diets. Increasing the level of available phosphorus (aP) in the control diets resulted in improved bird performance and bone ash data. The presence of dietary phytase in phosphorus deficient diets resulted in improvements in growth parameters and bone mineralization. Regression analysis confirmed that phytase supplementation can potentially increase the bioavailability of phosphorus in broiler diets up to 0.15 to 0.20 percent, however, the responses varied according to the enzyme used and inclusion level. In Experiment 2, a 42-day grow out trial was conducted to analyze the effects of NSPase inclusion on broiler performance and processing parameters when supplemented in diets with varying protein and energy concentrations. Reduced protein and energy levels reduced bird performance throughout the trial. The inclusion of both NSPase enzymes resulted in improvements in feed conversion throughout the starter and grower periods (day 26 of age). The results from this trial showed that NSPase inclusion can improve broiler performance and processing parameters. In Experiments 3 and 4, a battery trial and a floor trial were conducted to determine the effects of phytase and NSPase enzyme co-administration on growth and bone ash in low phosphorus diets. Increasing the level of available phosphorus resulted in increased bird performance and bone ash. The inclusion of phytase enhanced bird performance and bone mineralization. NSPase inclusion in diets containing low levels of phytase had improvements in bird performance during early stages of growth. The enhanced effects associated with dual administration of phytase and NSPase were not observed in a full grow out trial during later stages of growth. These four experiments indicate that phytase and NSPase enzyme inclusion in broiler diets have the ability to enhance bird performance, processing yield, and bone mineralization.Item Influence of dietary composition on coccidiosis vaccination efficacy in broilers(Texas A&M University, 2007-04-25) Lee, Jason ThomasThis research program included a series of experiments to investigate the effect of starter diet protein level on the performance of broilers vaccinated with Coccivac????-B and subsequently challenged with a mixed species Eimeria challenge compared to nonvaccinated broilers. Pre-challenge performance data indicates that vaccination may decrease body weights and increase feed conversion ratio (FCR) with vaccination. The time period associated with the observed effects is between 13 to 17 d of age. This reduction in performance of vaccinated broilers versus non-vaccinated broilers was eliminated by the conclusion of the experiments (27 d) in the higher protein diets. Vaccination was effective at generating protective immunity against the Eimeria challenge evidenced by significantly increased body weight gains, improved feed conversions, reduced post-challenge mortality, and reduced lesion development in vaccinated broilers compared to non-vaccinated. The final experiment included the comparison of Coccivac????-B to Bio-Cox???? (salinomycin) for controlling field strain Eimeria in broilers reared on two different dietary rations varying in protein concentration. Diet A had a lower protein concentration than Diet B. On day 14, Eimeria collected from commercial broiler farms in Texas were spray applied to the litter in all pens. Broilers reared on Diet B were heavier at Day 40 while body weights at day 50 were similar for all groups. Broilers fed Diet B had lower FCR during the starter and finisher diets. Broilers fed salinomycin had lower FCR for the starter and grower diets while vaccinated broilers had lower FCR during the withdrawal period. Cumulative FCR for the entire grow out period were similar for all groups. These data indicate that vaccination can be utilized as an anticoccidial preventive and are suggestive that reduced protein concentration of starter diets can lead to significant losses in broiler performance when utilizing a vaccination program to prevent coccidiosis. Feeding an appropriately formulated diet while vaccinating broilers with Coccivac????-B as an alternative to the use of salinomycin yields at least equivalent if not elevated performance in the presence of field-strain Eimeria during grow-out with no effect on the cost of production.