Effects of Dietary Protein Level and Phase Feeding Regimen on Growth Performance, Carcass Characteristics and Pork Quality in Growing-finishing Pigs

Two experiments were conducted to study the effects of dietary protein level and phase feeding regimens on performance, carcass characteristics and pork quality in growing-finishing pigs. In both experiments, growing pigs (n=90; barrows; Landrace $\times$ Yorkshire $\times$ Duroc) were allotted to 3 treatments. Each treatment had 3 replicate pens comprising 10 pigs in each. In Exp. 1, pigs (average body weight $25.06{\pm}0.57\;kg$) were fed diets having low (17.50-14.50-12.51%), medium (19.49-17.50-13.87%) or high (22.47-19.49-16.36%) CP concentration (LP, MP and HP diets, respectively) diets during grower-finisher I-finisher II phases, respectively. Feeding of MP diet resulted in higher (P<0.05) ADG and better FCR than pigs fed LP diet. Pigs fed HP diet had lower (P<0.05) pork color and marbling score. Meat of pigs fed LP diet had higher (P<0.05) Thiobarbituric acid reactive substances (TBARS), while meat of pigs fed HP and LP diets had greater drip loss than pigs fed MP diet. In addition, meat from pigs fed LP diet was darker while meat of pigs fed HP and MP diets was paler and redder. In Exp. 2, pigs (average body weight $10.40{\pm}0.61\;kg$) were subjected during 126 days to three or four phase regimes of different duration. The treatments T1 and T2 were subjected to four phase feeding regimens (grower I, grower II, finisher I and finisher II) for 22, 42, 32 and 30 days (T1) and 40, 40, 25 and 21 days (T2), respectively, while T3 was subjected to three phase feeding regimen (grower I, grower II and finisherI) for 40, 56 and 30 days, respectively. Duration of phase feeding regimens had no effect (P>0.05) on the performance, carcass traits and meat quality of pigs. These results suggest that both high and low levels of CP have a negative effect on performance and pork quality; however, alterations in the phase feeding regimens do not have any discernible effect on the performance and pork quality in growing-finishing pigs.