Effects of dietary vitamin B6 on the skeletal muscle protein metabolism of growing rabbits

This study aimed to evaluate the effects of dietary vitamin B-6 on the skeletal muscle protein metabolism and expression of transcription and growth factor of growing rabbits. Two hundred, healthy, rabbits with similar bodyweights were randomly assigned to one offive dietary groups with 40 animals per group. The dietary groups consisted of the following different vitamin B-6 supplementation levels: 0, 5, 10, 20 and 40 mg/kg. The feeding trial lasted 60 days. The results showed that dietary vitamin B-6 elicited significant effects on the fore and hind leg muscle ratio (the fore and hind leg muscle weight/the liveweight; P < 0.05) and on serum total amino acids (T-AA), blood urea and insulin-like growth factor 1 (IGF1) content (P < 0.05). Additionally, expression of IGF1, myogenic determination factor (MYOD) and myogenin (MYOG), myocyte regulation factor 5 (MYF5), myostatin (MSTN) and WW domain-containing E3 proteasome ubiquitin ligase 1 (WWP1) mRNA in the loin (M. longissimus dorsi) were affected by vitamin B-6 in diets (P < 0.05). The immunoblot analysis revealed that dietary vitamin B-6 elicited significant effects on IGF1, MYOG and WWP1 expression in the loin (P < 0.05). Our results indicate that the addition of dietary vitamin B-6 can significantly alter the protein metabolism of growing rabbits and that an appropriate vitamin B-6 supplementation level is 20 mg/kg for 3-5-month-old growing rabbits (the basic diet vitamin B-6 content was 4.51 mg/kg).