Effects of Trametes versicolor-Pseudostellaria heterophylla Fermented Substrate on Growth Performance, Rumen Function and Meat Quality of Kazakh Lambs

This experiment was conducted to investigate the effects of dietary supplementation with Trametes versicolor-Pseudostellaria heterophylla fermented substrate (TV-PHFS) on the growth performance, serum biochemical indices, rumen function, and meat quality of Kazakh ram lambs. Twenty-four Kazakh ram lambs (32.54 ± 5.23 kg) were randomly allocated into four groups, with six replicates per group and one lamb per replicate. The control group was fed a basal diet, while the experimental groups received the basal diet supplemented with 0.1, 0.2, and 0.3 kg/d of TV-PHFS, respectively, for a total duration of 140 days. The findings indicated that basal diet supplementation with TV-PHFS did not exert a statistically significant effect on the growth performance, serum antioxidant indices, and immune indices of Kazakh ram lambs (p > 0.05). However, compared with the control group, supplementation with 0.2 kg/d of TV-PHFS significantly elevated the 45 min postmortem yellowness (b*) value of the longissimus dorsi muscle and the relative abundance of Prevotellaceae_UCG_003 in the rumen (p < 0.05). Similarly, supplementation with 0.3 kg/d of TV-PHFS significantly increased the 24 h postmortem lightness (L*) value and crude fat content of the longissimus dorsi muscle, as well as the relative abundances of Treponema and Veillonellaceae_UCG_001 in the rumen (p < 0.05). In conclusion, basal diet supplementation with 0.3 kg/d of TV-PHFS modulated the rumen microbial community structure, promoted intramuscular fat deposition, improved muscle coloration, and augmented meat quality in Kazakh ram lambs.