Pellet die thickness and a commercial throughput agent interacted to demonstrate that high frictional heat increased apparent ileal amino acid digestibility, but did not influence trypsin inhibitor activity or male broiler pe

Authors: KNARR, LUCAS - West Virginia University; BOWEN, KRISTINA - West Virginia University; FERREL, J - Azomite Mineral Products, Inc; KIM, SUNHYUNG - University Of Missouri; Krishnan, Hari; MORITZ, JOE - West Virginia University

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2024
Publication Date: 8/18/2024
Citation: Knarr, L., Bowen, K., Ferrel, J., Kim, S., Krishnan, H.B., Moritz, J. 2024. Pellet die thickness and a commerical throughput agent interacted to demonstrate that high frictional heat increased apparent ileal amino acid digestibility, but did not influence trypsin inhibitor activity or male broiler pe. Journal of Applied Poultry Research. 33(4). https://doi.org/10.1016/j.japr.2024.100460.
DOI: https://doi.org/10.1016/j.japr.2024.100460

Interpretive Summary: Broiler production is a dynamic industry, where optimizing feed quality plays a pivotal role in achieving profitable outcomes. Understanding the intricate relationship between feed manufacture, pelleting parameters, and broiler performance is critical for poultry growers. In the United States, broiler diets are predominantly pelleted to reduce selective consumption, minimize ingredient segregation, enhance productive energy utilization, and improve handling characteristics and flowability. However, the impact of modifying pelleting parameters on nutrient digestibility, exogenous enzyme activity, and digestive inhibitor activity remains an area that warrants further investigation. In this study, we examined the effects of feed pelleting using varying inclusion rates of Azomite - a ground, solidified volcanic ash acting as a throughput agent—and different pellet die thicknesses on Ross 308 broiler performance. Our findings indicate that apparent ileal amino acid digestibility was influenced by our treatments, while broiler performance and trypsin and chymotrypsin inhibitor activity remained unaffected. These results empower US feed manufacturers to fine-tune Azomite inclusion rates and optimize pellet die thickness, ultimately enhancing poultry performance and increasing profitability.

Technical Abstract: Modifying pellet die thickness (PDT) has been shown to affect the frictional heat exposure of feed. The inclusion of Azomite (AZM) in broiler diets containing dicalcium phosphate has been shown to maintain apparent ileal amino acid digestibility (AIAAD). This is likely due to AZM's proposed die-scouring and lubrication properties that decreased the frictional heat exposure of feed which can change protein conformation and reduce AIAAD. Therefore, it was hypothesized that PDT and AZM would interact to influence AIAAD and broiler performance. The objective of the study was to determine the effect of AZM (0.0% or 0.25%) and PDT (32 and 45 mm; with a constant pellet diameter of 4.5 mm) on broiler performance and AIAAD from 0 to 21 d of age using a corn and soybean meal-based diet. Live performance was not influenced by AZM, PDT, or their 2-way interaction (P > 0.05). However, AIAAD was affected by AZM and PDT interactions (P < 0.05), with 11 amino acids demonstrating increased AIAAD in only the 45 mm control treatment. The AIAAD increase was likely not enough to influence performance. It was presumed that increased frictional heat deactivated trypsin inhibitors (TI) and chymotrypsin inhibitors (CTI), ultimately increasing AIAAD. Quantitative analysis of TI and CTI activity, utilizing a novel assay based on the current American Oil Chemists’ Society (Ba 12–75) and the American Association of Cereal Chemists International (22-40.01) accepted procedures, showed no practically influential amount of either inhibitor before or after pelleting. The authors, therefore, speculate that the increased AIAAD was due to corn aleurone layer cell wall lysis via increased frictional heat exposure of the 45 mm PDT and the absence of AZM.