Effects of different concentrate to forage ratio diets on the nutrient composition of the muscle of Qinghai Black Tibetan sheep

This study was conducted to investigate the effects of different concentrate to forage ratio diets on the levels of conventional nutrients, amino acids, and fatty acids of the longissimus dorsi of fattening black Tibetan sheep. A single factor randomized block design was used. Sixty 2-month-old healthy black Tibetan sheep with similar weight of (10.45 ± 0.96) kg were randomly divided into three groups with five replicates per group and four sheep per replicate. The three groups were fed diets with concentrate to forage ratios of 30 ꞉ 70 (C30), 50 ꞉ 50 (C50), and 70 ꞉ 30 (C70). The experiment lasted for 4 months, and 8 days during the pre-feeding period. After the feeding experiment, sheep were slaughtered and the longissimus dorsi muscle between the 12th and 13th ribs was collected to determine the related meat quality parameters. Results showed that there was no significant difference in moisture, crude protein, ash, and ether extract levels among the groups (P > 0.05). The content of methionine with the C30 diet was higher than that with the C50 (P < 0.05) and C70 (P < 0.05) diets, and the content of histidine with the C50 diet was significantly lower than that with the other two diets (P < 0.05). The content of pearl acid (C17 ꞉ 0) with C30 was significantly higher than that with the other two diets (P < 0.05), whereas trans-oleic acid (C18 ꞉ 1n9t) showed the opposite trend (P < 0.05). The content of conjugated linoleic acid (C18 ꞉ 2n6c) with the C50 diet was significantly lower than that with the other two diets (P < 0.05). In conclusion, when the ratio of concentrate to forage was 30 ꞉ 70, the levels of methionine, histidine, trans-oleic acid, and conjugated linoleic acid in the longissimus muscle of Qinghai black Tibetan sheep significantly increased, and the content of pearl acid significantly reduced.