Abstract:
Objective Effects of diet composition on growth performance, serum biochemistry and carcass trait-related gene expression of Sujiang pigs at final stage prior to slaughtering were investigated.
Method Randomly selected 162 Sujiang pigs with a body weight of (50.49±4.78)kg were divided in 9 groups with 3 replicates per group and 6 pigs per replicate (half male and half female) for the study. The diets used in the L9(34) orthogonal experiment were varied with 3 levels of digestible energy (DE) at 11.64, 12.24, and 12.84 MJ·kg-1, 3 levels of crude protein (CP) at 12%, 13%, and 14%, and 3 levels of crude fiber (CF) at 5%, 8%, and 11%. A pre-feeding period lasted 7 d followed by 42-d-feeding before sampling for serum analysis on the pigs.
Result (1) The TP content in the 12.84 MJ·kg-1 DE group was significantly higher than that in the 11.64 MJ·kg-1 DE group (P < 0.05), and GLB in the 12.84 MJ·kg-1 DE groups were significantly higher than those in the 11.64 and 12.24 MJ·kg-1 DE groups (P < 0.01). UN in the 8% CF and the 11% CF groups were extremely significantly (P < 0.01) and significantly (P < 0.05) higher than that in the 5% CF group. TC in the 14% CP groups were significantly lower than that in the 12% CP group (P < 0.01), and TG in the 14% CP group was significantly lower than that in the 12% CP group (P < 0.01). Glu in the 11% CF group was significantly lower than that in the 5% CF group (P < 0.01), and CREA in the 12.84 MJ·kg-1 DE group was significantly lower than that in the 11.64 MJ·kg-1 DE group (P < 0.05). (2) The serum insulin in the 12.84 MJ·kg-1 DE group was significantly higher than that in the 11.64 MJ·kg-1 DE group (P < 0.05). Serum T3 in the 11% CF group was significantly lower than that in the 5% CF group (P < 0.05). However, the dietary nutrition showed no significant effect on serum enzyme activities in the pigs (P>0.05). (3) The expressions of H-FABP and PRAKG3 genes in the longissimus dorsi muscle of the 11.64 MJ·kg-1 DE group were significantly higher than those in the muscle of the 12.24 and 12.84 MJ·kg-1 DE groups (P < 0.05), while that of HSL gene was significantly higher than those of 12.24 and 12.84 MJ·kg-1 DE groups (P < 0.01). The dietary CP or CF induced no significant effect on the expression of the genes in the pigs (P>0.05).
Conclusion Dietary DE, CP and CF affected the growth and development of Sujiang pigs at the final fattening stage through regulating the serum biochemistry and carcass trait-related gene expression of the animals. It appeared that a provision of DE at 12.84 MJ·kg-1, CP at 12%, and CF at 11% in the forage was appropriate for the pigs in that stage.