Effects of dietary cysteamine supplementation on growth performance and whole-body protein turnover in finishing pigs

The objective of this study was to investigate the effects of dietary cysteamine (CS) supplementation on growth performance and whole-body protein turnover in finishing pigs. This experiment contained 2 trials with the first trial of effect of dietary cysteamine supplementation on growth performance in finishing pigs for 47 d. A total of 16 PIC pigs (60.02 ± 1.01 kg; eight gilts and eight barrows) were randomly assigned to one of two dietary groups, with four pens per group (per pen: one gilt, one barrow). In the second trial, a total of eight PIC barrows (60.04 ± 1.02 kg) were randomly assigned to one of the two dietary groups, with four pens/group (one pig/pen) for 37 d and then the eight barrows were housed individually in metabolism crates (four barrows in control group and four barrows in CS group) for 10 d. The pigs of the first and second trials were fed a basal diet containing 0 (control) or 70 mg CS/kg diet. A total of eight barrows of the second trial received a 7-d nitrogen balance trial. 15N-Glycine (10 mg/kg BW) was gastrically infused after d 5 of the nitrogen balance trial. Feces and urine were collected daily to determine the N output. Results indicated that CS supplementation increased (P < 0.05) average daily gain (ADG), feed intake (ADFI), nitrogen retention, nitrogen retention efficiency, and efficiency of digestible N utilization. In addition, CS supplementation resulted in a decreased (P < 0.05) protein breakdown rate. Net protein gain in nitrogen was increased (P < 0.05) by 63.5%. However, protein synthesis rate, nitrogen flux, and endogenous urinary nitrogen were not affected (P > 0.05). It is concluded that dietary CS supplementation may improve growth performance in finishing pigs. Protein deposition is increased after dietary CS supplementation. This increase is caused by a decrease in protein breakdown.