Supplemental summer-autumn tea leaf (Camellia sinensis) improve the immune status of broilers

Summer-autumn tea leaf (SATL) is a waste tea plant resource which is not commonly used in tea industry due to its bitter and astringent taste. This study evaluated the effects of SATL-supplemented diet on broiler immune status. Accordingly, broilers were divided into control group and 3 SATL supplemented groups (0.5, 1.0, and 2.0%). The growth performance, immune organ index, serum antioxidant enzymes activity, sheep red blood cells (SRBC) Ab titers and Igs, as well as the Igs mRNA levels in the bursa of Fabricius were evaluated. The results showed that 1.0% and 2.0% SATL-supplemented diets significantly increased the relative thymus weight of broilers (P both < 0.05). 2.0% SATL treatment increased serum superoxide dismutase and glutathione peroxidase activities (P both < 0.01). Further, the serum SRBC Ab titers were significantly higher in the SATL-supplemented groups, meanwhile, IgY and IgA levels were remarkably elevated in the 1.0% and 2.0% SATL groups (P all < 0.05). In addition, an increasing of IgY and IgA mRNA levels in the bursa of Fabricius were observed in the 1.0% SATL group (P < 0.01). In summary, supplemental SATL can improve broiler immune status which indicates the potential application of SATL in broiler dietary supplement