Effects of dietary supplementation of cysteamine on growth performance, carcass quality, serum hormones and gastric ulcer in finishing pigs

A study was conducted to determine the effects of graded levels of dietary inclusion of a cysteamine (Cs) preparation on growth performance, carcass quality, plasma hormone levels, gastric pH and occurrence of gastric ulcer in finishing pigs. A total of 384 Landrace x Large White finishing pigs, (192 gilts and 192 barrows) with an average initial body weight of 66.05 ± 0.623 kg (mean ± SEM) were randomly divided into 24 floor pens, with eight gilts and eight barrows in each pen (9.2 m²) as one experimental unit. The 24 pens of pigs were randomly allocated to one of three diets: (1) a maize/soybean meal basal diet; (2) the basal diet plus 30 mg Cs kg^-1 diet; and (3) the basal diet plus 50 mg Cs kg^-1 diet. Dietary supplementation of Cs had quadratic effects (P < 0.01) on final body weight and average daily gain, with optimal responses occurring at 30 mg kg ^-1. Dietary supplementation of Cs quadratically improved (P < 0.01) average daily feed intake and feed/gain ratio, with optimal responses occurring at 30 mg kg^-1. Dietary supplementation of Cs had a quadratic effect (P < 0.01) on muscle RNA/DNA ratio. Furthermore, dietary supplementation of Cs reduced (P < 0.05) back-fat thickness. Dietary supplementation of Cs had quadratic effects (P < 0.05) on plasma glucagon and T₃ hormone levels, with optimal responses occurring at 30 mg kg ^-1, but had no effect (P > 0.05) on plasma growth hormone, insulin and T₄ levels. There were no apparent pathological changes seen in the stomach mucosa of pigs fed at 30 mg Cs kg^-1 compared with the control diet. It is concluded that a low dose of dietary inclusion of Cs at 30 mg kg^-1 can improve growth performance and carcass quality without adverse effects on the stomach in finishing pigs.