Effects of Dietary β-Mannanase Supplementation on Growth Performance, Apparent Total Tract Digestibility, Intestinal Integrity, and Immune Responses in Weaning Pigs

SIMPLE SUMMARY: Many plant-based feedstuffs contain non-digestible factors, such as β-mannans, that may reduce growth performance, as well as energy and nutrient digestibility. However, weaning pigs lack enzymes—such as β-mannanase—necessary to more completely digest β-mannan. Therefore, this experiment aimed to investigate the effects of dietary β-mannanase supplementation on growth performance, apparent total tract digestibility of nutrients, intestinal integrity and the immunological and oxidative stress parameters of weaning pigs. Our result suggested that adding β-mannanase to the weaning pigs’ diet increased the apparent total tract digestibility (ATTD) of ether extract, jejunum villus height, and villus height-to-crypt depth ratio, and lowered crypt depth compared with those fed the no-β-mannanase diet. This study indicated that the inclusion of β-mannanase showed the potential to improve fat digestibility, intestinal development and gut health of weaning pigs. ABSTRACT: The experiment aimed to investigate the effects of dietary β-mannanase supplementation on growth performance, apparent total tract digestibility (ATTD) of nutrients, intestinal integrity, and the immunological and oxidative stress parameters in weaning pigs. A total of 64 newly weaning pigs (initial body weight: 6.96 ± 0.70 kg) were allotted to two dietary treatments in eight replicates per treatment with four pigs per pen based on body weight and sex. Dietary treatments were 1.) CON (control: corn-soybean meal based basal diet) and 2.) β-mannanase (basal diet +0.06% β-mannanase). The β-mannanase supplementation did not affect growth performance, concentrations of acute phase protein, superoxide dismutase and glutathione peroxidase. However, the pigs fed the β-mannanase-supplemented diet had greater ATTD of ether extract, jejunum villus height, and villus height-to-crypt depth ratio, and lower crypt depth compared with those fed the CON diet (p < 0.05). The pigs fed the β-mannanase-supplemented diet tended to have the lower count of E. coli in cecum than those fed the CON diet (p = 0.08). In conclusion, dietary β-mannanase supplementation did not affect growth performance, immune response and oxidative stress of weaning pigs, whereas it increased fat digestibility and had positive effects on intestinal integrity and cecum microflora by reducing the count of E.coli.