Growth performance, carcass yield and characteristics, meat quality, serum biochemistry, jejunal histomorphometry, oxidative stability of liver and breast muscle, and immune response of broiler chickens fed natural antioxidant alone or in combination with Bacillus licheniformis

Abstract

In this study, oxidative stability of liver and breast meat, and immune response were evaluated in broiler chickens fed supplemental phytogenic feed additive (PFA) alone or in combination with Bacillus licheniformis. Three experimental groups - control, PFA (60 mg kg ${}^{-1}$ ), and PFA (60 mg kg ${}^{-1}$ ) $+$ 0.5 mg kg ${}^{-1}$ B. licheniformis (1.6 $\times$ 10 ${}^{12}$ cfu g ${}^{-1}$ ), each consisting of 5 replicates - were established with 20 one-day-old chickens per replicate (300 birds in total). Growth performance, carcass yield and characteristics, and meat quality remained unaffected. However, supplemental PFA and PFA $+$ B. licheniformis improved the serum biochemistry and jejunal histomorphometry of broiler chickens ( $P<0.05$ ). PFA and PFA $+$ B. licheniformis groups had lower thiobarbituric acid reacting substances (TBARS) in liver, and freeze-thaw breast meat after 30, 60, and 90 d of storage ( $P<0.05$ ). PFA and PFA $+$ B. licheniformis supplementation lowered the carbonyl group in fresh and stored breast meat ( $P<0.05$ ). Antibody titer against infectious bursal disease virus was higher in the PFA $+$ B. licheniformis group than the control group ( $P<0.05$ ). It can be concluded that PFA or PFA $+$ B. licheniformis in broiler diets improves the health, oxidative stability of liver and breast meat, and immune response of broiler chickens.