Date Published: May 28, 2019
Publisher: Public Library of Science
Author(s): Neeraja Recharla, Duwan Kim, Sivasubramanian Ramani, Minho Song, Juncheol Park, Balamuralikrishnan Balasubramanian, Pradeep Puligundla, Sungkwon Park, Juan J Loor.
This study was conducted in two stages to investigate the potential of multi-enzyme supplementation on the nutrient digestibility, growth performance, and gut microbial composition of pigs. In stage 1, effects of multi-enzyme complex (xylanase, α-amylase, β-glucanase, and protease) supplementation on the ileal and total tract dry matter (DM) digestibility of feed-stuffs were investigated with in vitro two-stage and three-stage enzyme incubation methods. A wide range of feed ingredients, namely, corn meal, wheat meal, soybean meal, fish meal, Oriental herbal extract, Italian rye-grass (IRG) and peanut hull were used as substrates. Supplementation of the multi-enzyme complex increased (P < 0.05) the digestibility of the Oriental herbal extract and corn meal. In stage 2, in vivo animal studies were performed to further investigate the effects of the dietary multi-enzyme complex on the nutrient utilization, growth performance, and fecal microbial composition of pigs. A total of 36 weaned pigs were fed corn- and soybean meal-based diets without (control) and with the multi-enzyme complex (treatment) for 6 weeks. Fecal samples were collected from 12 pigs to analyze the microbial communities by using DNA sequencing and bioinformatics tools. Multi-enzyme supplementation had no effect on apparent digestibility of nutrients and growth performance of pigs compared to control. Taxonomic analysis of the fecal samples indicated that the bacteria in both control and treatment samples predominantly belonged to Firmicutes and Bacteroidetes. In addition, the proportion of the phylum Firmicutes was slightly higher in the treatment group. At the genus level, the abundance of Treponema and Barnesiella increased in the treatment group; whereas the numbers ofthe genera including Prevotella, Butyricicoccus, Ruminococcus and Succinivibrio decreased in the treatment group. These results suggest that multi-enzyme supplementation with basal diets have the potential to improve nutrient digestibility and modify microbial communities in the hind-gut of pigs.
Many plant-based feed ingredients used in swine diets, especially cereal grains, contain large quantities of non-starch polysaccharides (NSPs) with anti-nutritional factors (ANFs). NSPs are poorly used by pigs because they lack specific endogenous enzymes for their breakdown, and, consequently, NSPs are fermented and used by pig intestinal microbes . The major NSPs of the plant cell wall are composed of cellulose (linear β-glucan chains), hemicellulose or non-cellulosic polymers (arabinoxylans, mixed-linked β-glucans, mannans, galactans, and xyloglucan) and pectic polysaccharides (polygalacturonic acids) . Elevated levels of NSPs in swine diets have adverse effects on nutrient digestibility and absorption rate. Especially, soluble NSPs increase the viscosity of digesta and alter the intestinal transit time. These effects could, in turn, lead to changes in the physiology and ecosystem of the gut [2,3]. The addition of exogenous NSP- degrading enzymes can improve nutrient availability in swine diets by breaking down the nutrient encapsulating cell wall as well as ameliorating viscosity problems associated with certain NSPs, particularly arabinoxylans and β-glucans [4,5].
Enzyme addition increased the in vitro total tract digestibility of Oriental herbal extract and corn meal. In the treatment group, multi-enzyme supplementation of the basal diet did not influence the nutrient digestibility and growth performance of the pigs. However, the microbial composition of the microbiota in the hindgut was modified by enzyme supplementation of the corn-soybean meal diet.