Efficacy of a Yeast Cell Wall Extract to Mitigate the Effect of Naturally Co-Occurring Mycotoxins Contaminating Feed Ingredients Fed to Young Pigs: Impact on Gut Health, Microbiome, and Growth

Abstract

Mycotoxins are produced by fungi and are potentially toxic to pigs. Yeast cell wall extract (YCWE) is known to adsorb mycotoxins and improve gut health in pigs. One hundred and twenty growing (56 kg; experiment 1) and 48 nursery piglets (6 kg; experiment 2) were assigned to four dietary treatments in a 2 × 2 factorial design for 35 and 48 days, respectively. Factors were mycotoxins (no addition versus experiment 1: 180 μg/kg aflatoxins and 14 mg/kg fumonisins; or experiment 2: 180 μg/kg aflatoxins and 9 mg/kg fumonisins, and 1 mg/kg deoxynivalenol) and YCWE (0% versus 0.2%). Growth performance, blood, gut health and microbiome, and apparent ileal digestibility (AID) data were evaluated. In experiment 1, mycotoxins reduced ADG and G:F, and duodenal IgG, whereas in jejunum, YCWE increased IgG and reduced villus width. In experiment 2, mycotoxins reduced BW, ADG, and ADFI. Mycotoxins reduced ADG, which was recovered by YCWE. Mycotoxins reduced the AID of nutrients evaluated and increased protein carbonyl, whereas mycotoxins and YCWE increased the AID of the nutrients and reduced protein carbonyl. Mycotoxins reduced villus height, proportion of Ki-67-positive cells, and increased IgA and the proportion of bacteria with mycotoxin-degrading ability, whereas YCWE tended to increase villus height and reduced IgA and the proportion of pathogenic bacteria in jejunum. The YCWE effects were more evident in promoting gut health and growth in nursery pigs, which showed higher susceptibility to mycotoxin effects.

Keywords: mycotoxin; prevention; reduction strategies.

Figure 1

Bacterial phyla (expressed as a percentage of relative abundance of sequences) collected from jejunal mucosa of weanling pigs fed diets with mycotoxins (MT) or and yeast cell wall extract (YC), based on 16S rRNA gene sequencing in experiment 2. Each pattern represents a particular bacterial phylum. Phylum sequences that did not achieve 1% within each phylum were combined as “Others”. MT-: diet without aflatoxin B1 and fumonisin B1; MT+: inclusion of 180 μg/kg aflatoxin B1, 1 mg/kg deoxynivalenol, and 9 mg/kg fumonisin B1 by replacing the clean corn and clean wheat with naturally mycotoxin-contaminated corn and wheat; YC 0%: no addition of yeast cell wall extract (YCWE; Mycosorb A+, Alltech, Nicholasville, KY, USA); YC 0.2%: YCWE added at 2 g/kg of feed.

Figure 2

Tight junction proteins of jejunal mucosa in weanling pigs fed diets with mycotoxin or/and yeast cell wall extract. Zo-1: zona occludens-1 protein; MT-: diet without aflatoxin B1 and fumonisin B1; MT+: inclusion of 180 μg/kg aflatoxin B1, 1 mg/kg deoxynivalenol, and 9 mg/kg fumonisin B1 by replacing the clean corn and clean wheat with naturally mycotoxin-contaminated corn and wheat; YC 0%: no addition of yeast cell wall extract (YCWE; Mycosorb A+, Alltech, Nicholasville, KY, USA); YC 0.2%: YCWE added at 2 g/kg of feed.