showed a trendP<0.05
Relative Expression of Genes in the Intestine With regard to antioxidant genes, the relative expression of nuclear factor erythroid 2-related factor 2 (Nrf2) showed a trend of increasing first and then decreasing with the addition levels of TB in feed, and the highest levels was observed in 0.06% TB supplementation in feed ( P<0.05 ), however, the relative expression of Kelch-like ECH-associated protein 1 (Keap1) showed an opposite trend with Nrf2.