Efficacy of a novel multi-enzyme feed additive on growth performance, nutrient digestibility and gut microbiome of weanling pigs fed corn-wheat or wheat-barley based diet

Abstract

One-hundred-and-ninety-two weanling pigs (6.7 kg BW) were used to evaluate the impact of a carbohydrases-protease enzyme complex (CPEC) on growth performance, nutrient digestibility, and gut microbiome. Pigs were assigned to 1 of 4 dietary treatments for 42 d according to a 2 × 2 factorial arrangement of diet type [low fiber (LF) or high fiber (HF)] and CPEC supplementation (0 or 170 mg/kg diet). The LF diet was prepared as corn-wheat-based diet while the HF diet was wheat-barley-based and contained wheat middlings and canola meal. Each dietary treatment consisted of 12 replicate pens (6 replicates per gender) and 4 pigs per replicate pen. Over the 42-d period, there was no interaction between diet type and CPEC supplementation on growth performance indices of pigs. Dietary addition of CPEC improved (P < 0.05) the body weight of pigs at d 28 and d 42 and the gain-to-feed ratio of pigs from d 0 to 14. During the entire experimental period, dietary CPEC supplementation improved (P < 0.05) the average daily gain and gain-to-feed ratio of pigs. There were interactions between diet type and CPEC supplementation on apparent total tract digestibility (ATTD) of dry matter (DM; P < 0.01), gross energy (GE; P < 0.01), and neutral detergent fiber (NDF; P < 0.05) at d 42. Dietary CPEC addition improved (P < 0.05) ATTD of DM, GE, and NDF in the HF diets. At d 43, dietary CPEC addition resulted in improved (P < 0.05) apparent ileal digestibility (AID) of NDF and interactions (P < 0.05) between diet type and CPEC supplementation on AID of DM and crude fiber. Alpha diversity indices including phylogenetic diversity and observed amplicon sequence variants (ASV) of fecal microbiome increased (P < 0.05) by the addition of CPEC in the HF diets on d 42. An interaction (P < 0.05) between diet type and CPEC addition on Bray-Curtis dissimilarity index and Unweighted UniFrac distances was observed at d 42. In conclusion, CPEC improved weanling pig performance and feed efficiency, especially in wheat-barley diets, while dietary fiber composition had a more significant impact on fecal microbial communities than CPEC administration. The results of this study underscores carbohydrase's potential to boost pig performance without major microbiome changes.