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

Abstract One-hundred-and-ninety-two weanling pigs (6.7 kg body weight) 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 one of the four 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 (six replicates per gender) and four 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 days 28 and 42 and the gain-to-feed ratio of pigs from days 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 day 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 of fecal microbiome increased (P < 0.05) by the addition of CPEC to the HF diets on day 42. An interaction (P < 0.05) between diet type and CPEC addition on Bray-Curtis dissimilarity index and Unweighted UniFrac distances was observed on day 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.