Feed particle size and amylase supplementation in diets for nursery piglets: Digestibility and growth performance

The objective of this study was to evaluate the effect of diet particle size, amylase supplementation, and their possible interaction on nutrient digestibility and performance of nursery pigs. A total of 352 whole male piglets (28-D-old) were distributed in a completely randomized block design with a 2 x 2 factorial scheme: 2 feed particle sizes; with or without inclusion of 80 kg-novo units (KNU) of amylase/kg. Initial weight was the blocking factor. The diets were pelleted, based on corn and soybean meal, and divided into pre-starter (28 to 42 d) and starter (43 to 63 d). The tested particle sizes were 339/588 pm and 696/920 pm for pre-starter and starter phases, respectively, and were obtained through grinding of the corn. Diets were fed ad libitum. Average daily feed intake (ADFI), average daily weight gain (ADWG), and feed conversion ratio (FCR) were evaluated. Apparent digestibility of dry matter (DM), crude protein (CP), and ether extract (EE), as well as digestible energy (DE) were additionally evaluated in the starter phase. No interaction between factors was observed throughout the experiment. In the pre-starter phase, piglets fed finer diets (339 pm) had lower FCR (P < 0.05), although ADFI and ADWG were not affected. In the starter phase, the use of a coarser diet (920 pm) led to greater ADFI and ADWG (P < 0.05), but with no effect on FCR, similarly to what was observed in the total period (28 to 63 days). Reducing the particle size increased EE digestibility (P < 0.05) but had no influence on DM and CP digestibility nor DE. Amylase supplementation increased ADFI and ADWG and reduced FCR in the pre-starter phase and total period (P < 0.05), and led to greater digestibility of DM, CP, and EE, as well as DE (P < 0.05). As a conclusion, fine grinding of diets can be applied to reduce FCR and increase fat digestibility in younger nursery pigs (up to 42-d-old), but coarser diets should be used at an older age (post-42-d) to prevent losses in ADFI and ADWG. Supplementation of 80 KNU/kg of exogenous amylase is recommended through the nursery phase (28 to 63 d) to improve growth performance, nutrient digestibility, and DE, regardless of diet particle size.

Automated summary

The objective of this study was to evaluate the effects of diet particle size and amylase supplementation on nutrient digestibility and performance of nursery pigs. The results showed that finer diet particle size reduces feed conversion ratio (FCR) and increases fat digestibility. Coarser diet particle size increases average daily feed intake (ADFI) and average daily weight gain (ADWG). The supplementation of amylase improves growth performance, nutrient digestibility, and digestible energy (DE).