Abstract
OBJECTIVE: This experiment was designed to determine the effects of coated cysteamine hydrochloride (CC) on muscle fiber characteristics, amino acid composition and transporters gene expression in the longissimus dorsi muscle (LDM) of finishing pigs. METHODS: Two hundred and sixteen Duroc/Landrace/Yorkshire cross-bred male finishing pigs were fed with a corn-soybean basal diet supplemented with 0, 70 and 140 mg/kg cysteamine. Each group contained eight replicates of nine pigs per replicate. After 29 days, one pig was randomly selected from each replicate and slaughtered. Blood and LDM samples were collected and analyzed. RESULTS: The results showed that supplemental dietary CC increased (P < 0.05) the muscle fiber density. And CC supplementation also up-regulated (P < 0.05) the expression of MyHC1 and MyHC2x mRNA levels, and down-regulated (P < 0.05) MyHC2b expression in the LDM. Additionally, supplemental dietary CC reduced (P < 0.05) the concentration of total cholesterol in the plasma and enhanced (P < 0.05) the concentrations of essential amino acid and total amino acid in the LDM. The relative expression levels of CAT2, b0,+AT, and y+LAT1 were up-regulated (P < 0.05) in the LDM when pigs were fed with the dietary CC of 70 mg/kg. CONCLUSION: Cysteamine supplementation could increase fiber density and distribution of fiber types. It also improved the deposition of protein in the LDM by up-regulated the expression of amino acid transporters.