LAUSR

This study was aimed to investigate the effects of betaine on intestinal structures and digestive enzyme activities of piglets. A total of 150 crossbred piglets (Duroc × Landrace × Yorkshire), with an average initial body weight of 8.52 ± 0.26 kg and age of 39-day, were randomly divided into three dietary treatments, each of which was replicated five times with ten pigs per replicate. The dietary treatments were basal diet supplemented with 0, 1250, 2500 mg/kg betaine, respectively. The experiments lasted for 30 days. The results showed that supplementation of betaine in the diet significantly increased average daily gain (P < 0.05), decreased diarrhea rate (P < 0.05), and improved feed conversion rate (P < 0.05) of piglets. The villus height and the ratio of villus height to crypt depth of small intestine were significantly increased with betaine supplementation (P < 0.05). The addition of betaine in diet also increased the expression of tight junction proteins in small intestine (P < 0.05) and decreased the diamine oxidase in plasma (P < 0.05). The apparent total tract digestibility of crude protein and ether extract (P < 0.05) and the activities of amylase, trypsin, and lipase (P < 0.05) in small intestinal were increased with betaine addition. Enzyme kinetic experiments in vitro indicated that hypertonic environment formed by NaCl could inhibit the activities of amylase and trypsin. While betaine addition improved the affinity of amylase and trypsin with their corresponding substrates, thereby counteracted the inhibitory effect of hyperosmolarity. In conclusion, the supplementation of betaine in diet could improve growth performance of piglets by ameliorating intestinal structure, increasing digestive enzymes activities, promoting the digestion of nutrients and decreasing the diarrhea rate.