Dietary supplementation of green tea by-products on growth performance, meat quality, blood parameters and immunity in finishing pigs

Abstract

Green tea has a long-standing reputation for its health-promoting properties. It has a useful content of amino acids, proteins, vitamins, tannins and polyphenols, such as epicatechin, epigallocatechin, epigallocatechin gallate and gallocatechin. This study evaluated the potential use of green tea by-products in finishing pig diet. A total of 100 finishing pigs were assigned to 5 dietary treatments with 4 replications for 6 weeks in a completely randomized design. The treatments were as follows: control (basal diet), antibiotic (basal diet with 0.003% chlortetracycline), and basal diet with 0.5, 1 or 2% green tea by-products (GTB). In this experiment, a poor weight gain and feed conversion ratio was observed for the GTB-2% group when compared with the antibiotic group. Both crude protein and crude fat contents of the meat were inversely proportional to each other in the GTB groups and 0.5 to 1% level differed with the antibiotic group. The slaughter weight and shear value were higher in GTB-1 and 0.5%, group respectively, while a lower heating loss and higher tenderness were observed in the GTB-2% group. Supplementation of the pig diet with GTB reduced the thiobarbituric acid reactive substances values of the meat, and increased white blood cells (WBC) and red blood cells (RBC) content compare to others. Although, spleen weight was decreased in the GTB-1 and 2% groups, spleen cells growth and, IL-6 and TNF-α production were improved by the addition of GTB to the feed. These combined results indicated that 0.5 to 1% GTB hold great promise to use as feed additive for finishing pigs. Key words: Green tea by-products, growth, meat, blood, immunity, pigs.