111 Increased dietary DL-methionine supplementation enhanced intestinal integrity and immunity in growing pigs.

Abstract Pig’s gastrointestinal tract is vulnerable to oxidative stress which can disrupt its structure and functionality. It has been reported that methionine (Met), a sulfur amino acid, can protect the gut against oxidative damages and enhance its health status. This study examined the effects of supplementing DL-Met above growth requirement on the intestinal histomorphology, integrity, and immunity in diquat-challenged growing pigs. Twenty individually penned barrows (average body weight (21.2. ± 2.01 kg) were used in 2 feeding trials with 10 pigs in each, which were randomly assigned to two treatment groups. Group 1 were fed a corn-and-soybean-meal-based diet that met or exceeded the NRC (2012) recommended requirements of nutrients and energy (SID lysine = 1.00%; SID Met+Cys =0.62%; net energy = 2531 kcal/kg), but Group 2 received the basal diet supplemented with more DL-Met (SID lysine = 1.00%; SID Met+Cys = 0.78; net energy = 2534 kcal/kg). After three weeks of feeding, each pig was injected with 10mg/kg-BW diquat in 10mL saline. After that, pigs continued their respective diets for one more week and were euthanized at the end of week 4. Ileum samples were collected for histomorphometric analyseis of villus height, villus width (VW), crypt depth, and goblet cell counts. Additionally, the mRNA expression levels of three integrity-associated genes (Muc-1, Muc-2, Muc-4), three tight junction genes (ZO-1, ZO-3, and Cld-1), and three immunity-associated genes (IL-6, IL-18, and TNF-α) in ileum tissue were quantitatively determined. Data was analyzed using PROC GLM in SAS. Results showed that ileal VW tended to be broader (P < 0.10) in pigs fed increased Met + Cys diet (Group 2 than in Group 1). Also, pigs in Group 2 showed higher level of integrity-associated gene Muc-2 (P < 0.05) and lower level of TNF-α, a pro-inflammatory cytokine (P < 0.05) compared to Group 1. In conclusion, the results of this study showed that additional DL-Met may increase ileal villus width and enhance the small intestinal integrity and immunity in pigs under oxidative stress.