Gastrointestinal dynamics, immune response, and nutrient digestibility of weanling pigs fed diets supplemented with enzymatically treated yeast1

Lay Summary The post-weaning stage is fraught with challenges that could affect piglet lifetime growth, development, and gut health. Various factors predispose pigs to stress after weaning. These factors include the separation of piglets from the sow, temperature changes, crowding stress, exposure to new animals, and dietary and environmental antigens. With the increased search for antibiotic alternatives in weanling pigs, identifying potential health-promoting feed additives is exigent. Enzymatically treated yeast (ETY) is rich in bioactive components, including immune-stimulating glucans, mannans, and peptides. These may confer beneficial effects on pigs during the post-weaning period. In this study, ETY was supplemented in graded levels in the diet of weanling pigs. Our results showed that dietary ETY supplementation influenced gut health by promoting a better antioxidant status in weanling pigs. Enzymatically treated yeast (ETY) did not significantly improve the growth performance of pigs. However, proof exists that ETY may enhance the antioxidative status of pigs, which may set them up for better lifetime development. The objective of this trial was to investigate the effect of enzymatically treated yeast (ETY) on the growth performance, nutrient digestibility, immune response, and gut health of weanling pigs. A total of 192 weanling pigs (6.0 +/- 1.04 kg) were allocated to 4 corn and soybean-based diets with increasing concentrations of ETY (0, 1, 2, or 4 g/kg) for a 43-d trial. There were 8 replicate pens (4 replicate pens per sex) and 6 pigs per replicate. The experiment was set up as a randomized complete block design with body weight used as a blocking factor. Pigs had ad libitum access to water and diets for the duration of the study. There was no effect of ETY supplementation on the growth performance indices of weanling pigs. At day 14, there was a quadratic decrease (P < 0.05) in the apparent total tract digestibility (ATTD) of acid detergent fiber (ADF). At day 28, there was a linear increase (P < 0.05) in the ATTD of neutral detergent fiber and a quadratic decrease (P < 0.05) in the ATTD of ADF. On day 14, there was a linear increase (P < 0.05) in serum catalase activity with ETY supplementation. There was a linear increase (P < 0.01) in the gene expression of glutathione peroxidase-4 in the ileal mucosa of pigs. Increasing dietary ETY supplementation linearly decreased (P < 0.05) the gene expression of ileal peptide transporter 1. There was a tendency for a quadratic effect (P = 0.07) in the ileal villus height to crypt depth ratio with ETY supplementation. In addition, there was a tendency for a linear increase (P = 0.06) in ileal digesta butyrate with ETY supplementation. In conclusion, the current study demonstrated that dietary ETY supplementation could partly ameliorate the deleterious effects of post-weaning stress by enhancing the antioxidative status of weanling pigs. However, prolonged supplementation of ETY may be needed to see its effect on growth performance.

Automated summary

Supplementing enzymatically treated yeast (ETY) in piglet diet can partly improve the antioxidative status but has limited effect on growth performance. The addition of enzymatically treated yeast (ETY) in the diet can promote gut health in piglets to a certain extent. Further research is needed to investigate the long-term effect of enzymatically treated yeast (ETY) on growth performance.