The purpose of this study was to investigate the optimum proportion of sorghum straw and ammoniated wheat straw in vitro and in vivo to apply in ruminant diets. One-factor and two-factor experimental designs were used in the in vitro tests, with different ratios of sorghum straw to ammoniated wheat straw (S:AWS) of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, and 8:2 to measure the in vitro total gas production, CH₄ production, in vitro dry matter degradability (IVDMD), in vitro organic matter degradability (IVOMD) and in vitro fermentation parameters. Additionally, the nylon bag technique was used to determine the dynamic degradation of these different ratios of mixed feedstuffs for incubating in sheep rumen for 6 h, 12 h, 24 h, and 48 h. The results show that IVDMD, IVOMD, and the molar ratio of propionate were the highest when the ratio of S:AWS was 8:2 (p < 0.05) in vitro; however, this ratio released much more CH₄ (p < 0.05). In addition, the degradability of DM, OM, CP, and ash and the effective degradability of DM and CP were the highest when the ratio of S:AWS was 8:2 cultured in sheep rumen for 48 h (p < 0.05). In the in vitro and in situ nylon bag tests, IVDMD, IVOMD, rumen nutrient degradability, and effective degradability of DM and CP increased with the increase in the sorghum straw proportion. In conclusion, the higher the proportion of sorghum straw, the higher the nutrient degradability in vivo and in vitro, but also the higher the emissions of CH₄. Therefore, when the ratio of S:AWS is 8:2, ruminants can effectively utilize nutrients in feed.

The aim of this experiment was to study the sustained effects of early supplementation with a starter on the performance of lambs during the pre-weaning, post-weaning, and fattening periods. Sixty male Hu lambs (3.59 ± 0.05 kg) were randomly assigned to two (30 lambs per group) treatments. The lambs were fed milk replacer from three days of age. The early supplementation (ES) group was supplemented with a starter ration at seven days of age, the control (CON) group was supplemented at 21 days of age, and lambs in both groups were weaned from milk replacer at 28 days of age. Eight lambs from each group were randomly slaughtered at 98 days of age, and the remaining lambs were fed the same nutrient level of a fattening ration until slaughter at 200 days of age. The results showed that early supplementation with starter significantly improved average daily feed intake (ADFI) and average daily weight gain (ADG) in the pre-weaning period (7–28 days of age), and ADFI and slaughter performance (live weight before slaughter, carcass weight and dressing percentage) in the post-weaning period (29–98 days of age, p < 0.05). In addition, early supplementation with the starter had no significant effect (p > 0.05) on ADFI, ADG, and slaughter performance, but significantly decreased (p < 0.05) the feed-to-gain ratio (F/G) of lambs during the fattening period (99–200 days of age). In addition, early supplementation with starter increased the ratio of rumen and reticulum weight to total stomach weight in lambs (p < 0.05). In conclusion, early supplementation with starter can reduce feed costs and improve the performance of lambs, while the growth advantage produced by early supplementation had initially disappeared by 154 days of age.

Background: The prolonged cold season on the Qinghai-Tibet Plateau poses substantial challenges for most animals, including limited access to natural pasture, reduced appetite, and subsequent weight loss. The polysaccharides that are contained in yeast cell wall (YCW) act as prebiotics, promoting the action and development of beneficial gut microbiota while inhibiting the proliferation of pathogens, thereby maintaining normal gastrointestinal function in animals. Methods: This research aimed to examine how incorporating yeast cell wall (YCW) into the diet influences rumen fermentation, the composition of microbiota, and liver metabolism in Tibetan sheep. A total of 30 one-year-old Tibetan sheep, with an mean weight of 30.51 ± 7.07 kg, was randomly assigned to groups: a control group and a supplementation of 0.3% YCW group. Each group consisted of 15 sheep. The experimental period lasted for 98 days. Results: The research showed that the addition of YCW increased Dry matter digestibility and average daily gain (ADG) of Tibetan sheep significantly ( P < 0.05); the concentrations of propionic acid, acetic acid, total volatile fatty acids, and ammonia nitrogen in the rumen were significantly increased ( P < 0.05); In the liver, the mRNA expression of genes associated with gluconeogenesis, including Glucose-6-phosphatase, catalytic subunit (G6PC), Phosphoenolpyruvate carboxykinase 1(PEPCK1), and Fructose-1,6-bisphosphatase (FBP), were significantly increased following YCW supplementation ( P < 0.05); the mRNA expression level of Sterol regulatory element-binding protein 1c (SREBP1c), which is involved in lipid metabolism, was significantly decreased ( P < 0.05); The inclusion of YCW in the diet reduced the relative abundance of Desulfobacterota and Firmicutes significantly, and increased Prevotella ’s abundance significantly in the rumen ( P < 0.05). Liver metabolites were substantially enriched in the glycerolipid metabolism, glycolysis/gluconeogenesis, and the AMP-activated protein kinase (AMPK) signaling pathway ( P < 0.05). Conclusions: YCW supplementation in feed may advance the growth and gain of Tibetan sheep and improve gluconeogenesis. This effect may be ascribed to modifications in the rumen microbiota facilitating propionic acid fermentation, subsequently regulating liver lipid metabolism.