Evaluation of green tea by-product and green tea plus probiotics on the growth performance, meat quality and immunity of growing–finishing pigs

The present study was conducted to evaluate the effects of green tea by-product (GTB) and green tea plus probiotics (GT+P) on the growth performance, carcass characteristics, meat quality, blood parameters and immunity of growing–finishing pigs. In total, 80 crossbreed growing pigs were assigned to receive four dietary treatments for a period of 8 weeks. The dietary treatments were a basal diet (control), basal diet supplemented with 0.003% chlortetracycline (antibiotic), basal diet with 0.5% GTB (GTB) and basal diet containing 0.5% GT+P (GT+P). The results of our study indicated that bodyweight gain increased (P < 0.05) in response to the addition of GT+P to the basal diet. Crude protein and crude ash content, and shear values of loin meat were significantly (P < 0.05) increased in the GT+P group, although moisture and juiciness were decreased (P < 0.05). The GTB group had higher (P < 0.05) serum glucose concentrations, whereas the GT+P exhibited lower (P < 0.05) insulin concentrations. The values of thiobarbituric acid-reactive substances of fresh loin meat and meat that had been preserved for 1 week were lower (P < 0.05) in the GT+P group than those of the control and GTB groups. The growth of spleen cells incubated in concanavalin A (Con A) and lipopolysaccharide (LPS) medium was statistically higher (P < 0.05) for the GT+P group than for the GTB or antibiotic group. IL-6 and TNF-α production by spleen cells induced by Con A and LPS was increased in the GTB and GT+P group (P < 0.05) compared with the antibiotic group. Taken together, the results of the present study indicated that GT+P exerts positive effects on weight gain, meat composition, blood parameters and immunity in pigs, and could be used as an alternative to antibiotics for growing–finishing pig feeds.