Location: Poultry Research
2023 Annual Report
Objectives
1. Determine the effectiveness of altering the balance and concentration of dietary nutrients to reduce incidence, severity, and adverse performance associated with enteric infections.
1.A. Assess effects of dietary mineral sources and concentrations on necrotic enteritis infections in broilers.
1.B. Determine effects of dietary fiber types and concentrations on susceptibility and severity of necrotic enteritis infections in broilers.
1.C. Evaluate dietary amino concentrations and feed ingredients and the interactive effects of dietary minerals, fiber, and amino acid concentrations on broiler resiliency during enteric infections.
2. Characterize the physical and chemical components of feed ingredients and diets and their effect on feed utilization and gastrointestinal function of healthy and enteric infection affected broilers.
2.A. Determine the effect of ingredient particle size and dietary pellet quality on nutrient utilization and gastrointestinal function in broilers with and without enteric infections.
2.B. Determine the physical and chemical composition effects of alternative ingredients on broiler nutrient utilization and gastrointestinal function in broilers with and without enteric infections.
3. Identify physiological and microbiological biomarkers associated with subclinical enteric infections.
3.A. Conduct hematological, tissue, bacterial, and short chain fatty acid analyses to determine physiological and microflora differences in broilers with and without subclinical enteric infections.
3.B. Evaluate the effects of subclinical enteric infections on muscle protein degradation rate in broilers.
Approach
Approximately 9 billion broilers are produced annually in the United States. For decades boilers have been fed diets with sub-therapeutic levels of antibiotic growth promoters (AGP) to enhance growth rate and efficiency. The human medicine community has raised concerns of antimicrobial resistance with the consumption of poultry products originating from broilers fed diets with AGP. Consequently, consumers have placed demands to reduce the use of AGP. The removal of AGP from broiler diets has led to increased incidences of subclinical enteric infections such as coccidiosis and necrotic enteritis which has decreased animal productivity resulting in increased economic losses. Anticoccidial vaccines are live vaccines, and most anticoccidial vaccines on the American market are fully virulent. Their use requires careful management, and vaccine strains themselves can negatively affect broiler performance. Therefore, comprehensive nutritional research exploring factors such as optimal balance and concentrations of nutrients, physical and chemical components of ingredients and diets, and biomarkers of subclinical enteric infections are warranted to optimize gastrointestinal health, nutrient utilization, and performance of broilers without in-feed AGP. This research will explore the effectiveness of altering the balance and concentration of dietary nutrients (calcium, amino acids, and fiber) to reduce the incidence and severity of enteric infections. Additionally, this research will characterize the physical (ingredient particle size and pellet quality) and chemical (alternative ingredients) components of feed ingredients and diets on nutrient utilization and gastrointestinal function of healthy and enteric infected broilers. Lastly, this research will identify physiological (gastrointestinal structure and function, immune responses, genetic expression, and protein turnover rate) and microbiological (gastrointestinal microbiome) biomarkers associated with subclinical enteric infections to help refine nutritional strategies. Determining optimal balance and concentration of nutrients for gastrointestinal health and performance will equip industry nutritionists with formulation strategies to reduce the incidence and severity of enteric infections. Characterizing physical and chemical components of feed ingredients and diets will assist feed mill managers in developing processing techniques to optimize nutrient utilization. Identifying physiological and microbiological biomarkers associated with subclinical enteric infections will benefit the poultry industry and scientific community at large by generating information to refine nutritional strategies. Overall, this research will benefit consumers by meeting their demands while providing a healthy, cost-effective, high quality protein source.
Progress Report
This is the initial report for project 6064-32630-011-000D “Reducing the Impact of Subclinical Enteric Infections on Performance and Gastrointestinal Function of Broilers.”
Research conducted to address Objective 2 is designed to characterize the physical and chemical components of feed ingredients and diets and their effect on feed utilization and gastrointestinal function of healthy and enteric infection affected broilers. For Objective 2A, the goal is to determine the effect of ingredient particle size and dietary pellet quality on nutrient utilization and gastrointestinal function in broilers with and without enteric infections. A survey and an experiment were conducted to determine the range of ingredient particle sizes and pellet quality observed in commercial broiler diets. These results helped establish relevant thresholds to ensure industry applicability. Experiments to address research for Objective 2A are currently ongoing and will be completed in in FY24.
Research conducted to address Objective 3 is to identify physiological and microbiological biomarkers associated with subclinical enteric infections. The goal of Objective 3B is to evaluate the effects of subclinical enteric infections on muscle protein degradation rate in broilers. Experiments to address research for Objective 3B are currently ongoing and will be completed in FY23 and analysis will begin in FY24.
Accomplishments
1. Evaluation of individual and combined effects of antibiotic growth protomer (AGP) alternatives (phytase and butyric acid) on performance, yield, and intestinal health of broilers. Reduced use of AGP in broiler diets has led to increased incidence of intestinal disease and reduced growth performance. Consequently, the need for cost-effective and efficacious AGP alternatives have increased to help maintain broiler health and performance in the absence of AGP. ARS researchers in Starkville, Mississippi, collaborated with researchers at Auburn University to evaluate the impact and efficacy of phytase and butyric acid as AGP alternatives in growing broilers when compared with diets with AGP. This research demonstrated that broiler performance, health, and physiology can be altered with the supplementation of these additives. In general, growth performance was most improved with the supplementation of AGP when compared with phytase and butyric acid. However, improvements in broiler growth performance were observed with phytase and butyric acid. Moreover, improvements in broiler intestinal health (cecal microbiome) and physiology (villus length, crypt depth, tight junction gene expression) were observed with feeding a combination of phytase and butyric acid. These results indicated that phytase and butyric acid may be supplemented as efficacious AGP alternatives to help maintain broiler health and performance in the absence of AGP.
2. Evaluation of pellet die condition and wear on the physical quality of pellets and final feed composition of commercial broiler diets. Increasing the dietary density of feed through pelleting has been observed to improve nutrient utilization and growth performance in broilers. Optimizing nutrient utilization through physical improvements in dietary quality not only improves broiler growth performance but can also help fortify intestinal health by minimizing the concentration of unabsorbed nutrients in the hind gut which reduces the proliferation of opportunistic bacteria. Consequently, optimizing milling conditions to maximize physical feed quality will help develop processing techniques to maximize nutrient utilization. The pellet die is a key element in pelleting. Consequently, it was hypothesized that the condition of the die and its wear over time would impact the physical quality (formation and durability of pellets and final feed composition) of broiler diets. ARS researchers in Starkville, Mississippi, collaborated with a broiler integrator to determine the impact of die condition (new or reconditioned) and wear (12-week period) on pellet quality and finished feed composition from 4 commercial feed mills. This research demonstrated that neither die condition nor wear affected the quality of dietary pellets and finished feed composition. However, differences in dietary quality among the commercial feed mills indicated that further research evaluating milling conditions is warranted to reduce sources of variation and improve physical characteristics of broiler diets in order to optimize nutrient utilization and performance in broilers.
3. Evaluation of an alternative protein ingredient (insect meal) on apparent metabolizable energy (AME) and live performance of broilers. Including insect meal as an alternative protein source in broiler diets has received increased attention due to population growth projections and the demand for quality and cost-effective alternative feed ingredients. However, the economic and environmental benefit of insect meal as an alternative protein source in broiler diets largely depends on the insects’ ability to utilize plant or food wastes of low nutritional value or those contaminated with mycotoxins (fungal-produced toxins) at concentrations unsafe for animal consumption. Moreover, the benefits of feeding insect meal derived from Deoxynivalenol (DON) contaminated grain as an alternative ingredient depends on its nutrient availability and its impacts on nutrient utilization, performance, gastrointestinal function and health of broilers. Therefore, ARS researchers in Starkville, Mississippi, collaborated with insect production company to determine safety and efficacy of feeding insect meal derived from meal worms reared on DON contaminated diets as an alternative protein ingredient in broiler diets. The dietary inclusion of insect meal did not negatively affect broiler growth performance during the starter or grower periods. Feeding broilers diets with insect meal led to some improvements in growth rate and feed efficiency when compared with those fed the negative control. Moreover, insect meal inclusion did not affect AME. These results demonstrated that insect meal derived from yellow meal worms reared on DON contaminated diets can be incorporated as a safe and efficacious alternative protein source in broiler diets.
Review Publications
Mccafferty, K.W., Purswell, J.L. 2023. Effects of feeding varying proportions of pellets and fines on growth performance and carcass yield of broilers during a 63-day production period1. Journal of Applied Poultry Research. 32(2). Article 100332. https://doi.org/10.1016/j.japr.2023.100332.
Mccafferty, K.W., Purswell, J.L. 2023. Applied Research Note: Effects of various concentrations of supplemental biochar on ileal digestible energy and live performance of broilers during an 8-wk production period. Journal of Applied Poultry Research. 32(1). Article 100323. https://doi.org/10.1016/j.japr.2022.100323.
Ennis, C.E., Gehring, C.E., Bedford, M.R., Wyatt, C.L., Wamsley, K.G. 2020. Strategies to determine the efficacy of multiple phytase use at low activities using Ross x Ross 708 male broilers from 0 to 14. Journal of Applied Poultry Research. 29(4):977-994. https://doi.org/10.1016/j.japr.2020.09.006.
Hirai, R.A., Mejia, L., Coto, C., Caldas, J., Mcdaniel, C.D., Wamsley, K.G. 2020. Impact of varying starter amino acid density and energy on 42 d male Cobb MV × Cobb 500 broiler performance and processing. Journal of Applied Poultry Research. 29(4):1004-1019. https://doi.org/10.1016/j.japr.2020.09.009.
Brown, A.T., Lemons, M.E., Perryman, K., Kiess, A.S., Wamsley, K.G. 2021. Determining the relationship between varying inclusions of Bacillus lichenformis and tribasic copper chloride on 42-day-old Ross 708 male broiler performance. Journal of Applied Poultry Research. 30(1). Article 100109. https://doi.org/10.1016/j.japr.2020.10.008.
