Effects of purified polymannuronate on the performance, immune status, antioxidant capacity, intestinal microbial populations and volatile fatty acid concentrations of weaned piglets

The aim of this study was to assess the effects of purified, low-molecular-weight, polymannuronate on the performance, immune status, antioxidant capacity and the intestinal tract fermentation profile of weaned piglets. In a 28-d experiment, 180 crossbred Duroc × (Landrace × Yorkshire) piglets weighing 9.19 ± 1.47 kg and weaned at 35 days of age, were divided into 5 groups and fed corn-soybean meal based diets supplemented with 0, 3, 4, 5 or 6 g/kg polymannuronate (supplemented at the expense of corn). Each treatment was replicated 6 times with 6 pigs per replicate. Average daily gain (ADG), gain to feed (G:F) ratio as well as the serum IgM and hepatic glutathione linearly increased (P < 0.01) with increasing level of polymannuronate. Supplementation with increasing levels of dietary polymannuronate resulted in increased numbers of ileal and colonic lactic acid bacteria (linear effect, P < 0.01). The number of E. coli in ileum and colon was linearly decreased (P < 0.05) with increasing level of polymannuronate. At the end of the experiment, ileal and cecal lactic acid concentrations were significantly linearly increased (P < 0.01) with increasing level of polymannuronate. The concentration of butyric acid in the cecum, acetic acid and total VFA in colonic were also linearly increased (P < 0.05) with increasing polymannuronate inclusion levels. These results indicate that polymannuronate can improve immune status, antioxidant capacity and performance of weaned piglets.