Effects of Tea Polyphenols on Post-Weaning Meat Quality and Antioxidant Status in Lambs

In this present study, we aimed to investigate the effects of adding tea polyphenols to feed on the meat quality, muscle antioxidant capacity, and muscle fatty acid composition of lambs. Forty healthy 45-day-old weaned lambs with similar body weights (average initial weight 9.1 ± 0.8 kg) were randomly divided into four treatment groups (n = 10) for a 45-day trial. The control group (CON) was fed a basal diet, while the other three groups (TP2, TP4, and TP6) received the basal diet supplemented with 2, 4, and 6 g/kg of tea polyphenols, respectively. Supplementation with tea polyphenols significantly reduced the cooked meat rate of biceps femoris in the TP2 and TP6 groups, and significantly increased the pH values of triceps brachii at 0 h and 24 h in the TP6 group (p < 0.05). Increased activities of total superoxide dismutase in the longissimus dorsi and glutathione peroxidase in biceps femoris, significantly decreased contents of hydrogen peroxide in the biceps femoris and triceps brachii, and significantly increased activity of catalase in triceps brachii were observed (p < 0.05). TP4 and TP6 significantly increased the activities of the total antioxidant capacity in biceps femoris and glutathione peroxidase in triceps brachii, and significantly decreased the concentration of malondialdehyde in biceps femoris (p < 0.05). The dietary tea polyphenols significantly increased the contents of C16-1, C18-1n9t, C18-2n6c, C18-3n3, C18-3n6, n-3 PUFAs, and n-6 PUFAs in the longissimus dorsi of the TP6 group (p < 0.05), and the ratio of n6/n3 in the biceps femoris of lambs changed significantly (p < 0.05). In addition, the relative expression levels of myosin heavy chainsI (MyHCI) and MyHCIIa mRNAs in the muscles were significantly increased, and the relative expression levels of MyHCIIX and MyHCIIB mRNAs in the muscles were significantly decreased. And in terms of comprehensive economic benefits, it is most appropriate to add 6 g/kg tea polyphenols to the diet.