Location: Poultry Research
2024 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
A study evaluating the effects varying limestone particle size and calcium concentration on broiler performance and tibia mineralization when challenged with necrotic enteritis (Objective 1: Determine the effectiveness of altering the balance and concentration of dietary nutrients to reduce incidence, severity, and adverse performance associated with enteric infections) was conducted. A study evaluating the effects of ingredient particle size and dietary pellet quality on nutrient utilization and gastrointestinal function in broilers with and without enteric infections (Objective 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) was conducted (study 2), the analysis of study 1 was completed, and the publication of study 1 is ongoing and will be completed in fiscal year (FY) 2025. The muscle protein degradation analysis (Objective 3: Identify physiological and microbiological biomarkers associated with subclinical enteric infections) is currently ongoing and will be completed in FY 2025. Also, the feed mill was renovated and brought back online after 2 years of renovations.
Accomplishments
1. Dietary calcium and necrotic enteritis in broilers. Excess dietary calcium can be a predisposing factor for necrotic enteritis development in broilers because it plays a central role in phospholipase substrate binding. In addition, the particle size of the calcium source may affect its solubility and availability. Therefore, diets with varying dietary calcium concentrations and limestone particle sizes were fed by ARS researchers at Mississippi State, Mississippi, to broilers challenged with necrotic enteritis to determine if modulating calcium particle size and concentration can reduce the impact and severity of necrotic enteritis. This study demonstrated that reducing dietary calcium concentrations by 0.10% from the adequate calcium can maintain broiler performance and tibia mineralization during a necrotic enteritis challenge. However, this outcome was influenced by calcium particle size and should also be considered during formulation. These results indicate that modulating calcium concentration and the particle size of limestone can be effective nutritional strategies for reducing the incidence and severity of necrotic enteritis infections in broilers.
2. Physical feed quality and coccidiosis in broilers. The physical quality of feed has been observed to affect the performance, nutrient utilization, and gastrointestinal morphology of broilers. Dietary physical quality is manipulated through ingredient particle size and pellet quality. Optimizing the physical quality of broiler feed has potential to not only improve broiler performance but also to help fortify gastrointestinal health and function to minimize enteric infections. Therefore, this study by ARS researchers at Mississippi State, Mississippi, evaluated the effects of corn particle size and crumble quality of feed fed to broilers during the starter period when challenged with coccidiosis. Overall, the most consistent benefit was observed when birds were fed the diet with the moderate corn particle size and the high crumble size. This is beneficial to poultry integrators because it not only provides guidance on the optimal physical feed quality to achieve best performance during the starter phase, but it also will provide cost-savings for feed manufacturers because a higher crumble size would reduce the energy needed for pellet crumbling.
3. Feed mill upgrades. The feed mill was upgraded with new equipment and technology by ARS researchers at the Mississippi State University location, to help improve feed production.
Review Publications
Hirai, R.A., Mejia, L., Coto, C., Caldas, J., Mcdaniel, C.D., Wamsley, K.G. 2019. Evaluating the response of Cobb MV x Cobb 500 broilers to varying amino acid density regimens for a small bird program.. Journal of Applied Poultry Research. 28(4):943-962. https://doi.org/10.3382/japr/pfz055.
Mccafferty, K.W., Purswell, J.L. 2024. Effects of production time, die condition, and feed mill on the physical quality of commercial broiler diets. Journal of Applied Poultry Research. 33(3). Article 100430. https://doi.org/10.1016/j.japr.2024.100430.
Liu, J., Robinson, K., Lyu, W., Yang, Q., Wang, J., Christensen, K.D., Zhang, G. 2023. Anaerobutyricum and subdoligranulum are differentially enriched in broilers with disparate weight gains. Animals. 13(11). Article 13041071. https://doi.org/10.3390/ani13111834.
Robinson, K., Duffield, K.R., Ramirez, J.L., Cohnstaedt, L.W., Ashworth, A.J., Jesudhasan, P., Arsi, K., Morales Ramos, J.A., Rojas, M.G., Crippen, T.L., Shanmugasundaram, R., Vaughan, M.M., Webster, C.D., Sealey, W.M., Purswell, J.L., Oppert, B.S., Neven, L.G., Cook, K.L., Donoghue, A.M. 2024. MINIstock: Model for INsect Inclusion in sustainable agriculture: USDA-ARS's research approach to advancing insect meal development and inclusion in animal diets. Journal of Economic Entomology. 117(4):1199-1209. https://doi.org/10.1093/jee/toae130.
