The effects of altering diet formulation and manufacturing technique on pellet quality

Abstract

SUMMARY Least-cost diet formulations and pellet mill operating techniques vary widely. As a result, pellet quality is often inconsistent. Past research has associated pellet quality changes with feed formulation and manufacturing techniques. However, the interaction between the 2 factors has rarely been explored. The objective of the current study was to evaluate the effects of altering a least-cost diet (LC) formulation and altering manufacturing techniques on pellet processing variables and quality. Generally, pellet quality improves with higher levels of protein and moisture. Therefore, increased levels of CP and moisture were added to LC broiler starter and grower formulations to compose a research-based (RB) formulation. The LC and RB formulations were pelleted using 2 manufacturing techniques, a thin die with a fast production rate (TF) or a thick die with a slow production rate (TS). During manufacture of the starter diets, the RB formulation improved the pellet durability index (PDI) and modified PDI (MPDI) while decreasing pellet mill relative electrical energy usage (P ≤ 0.05) compared with the LC formulation. The TS technique increased PDI and MPDI while decreasing production of fines (P ≤ 0.05) compared with the TF technique. During manufacture of the grower diets, the RB formulation and TS technique resulted in decreased production of fines (P ≤ 0.05) compared with the LC formulation and TF technique. A significant interaction observed for PDI and MPDI of the grower diets indicated that the RB formulation improved pellet quality and would be even more beneficial if a mill used a TF technique (P ≤ 0.05). We conclude that diet formulation and manufacturing technique are, in fact, linked and must be considered when attempting to optimize pellet quality.