This study aimed to investigate the effects of Yucca schidigera extract (YSE) on growth performance, serum immune parameters, rumen microbiota, and metabolites of fattening goats. For this purpose, thirty-two healthy male Boer goats with similar initial body weights (36.91 ± 3.05 kg) were randomly assigned to four groups. Goats in the control group (Group A) were fed a basal pelleted diet, whereas the experimental groups (Groups B, C, and D) received 200, 400, and 600 mg of YSE per kg of basal diet, respectively. The results reveal that dietary supplementation with 600 mg/kg YSE significantly elevated average daily gain (ADG) and decreased feed-to-gain ratio (F/G) (p < 0.05). The 400 mg/kg YSE addition significantly increased serum IgM concentration and reduced the TNF-α concentration (p < 0.05). Meanwhile, 400 mg/kg dietary YSE supplementation significantly elevated Ace and Chao-1 indices of ruminal microbiota (p < 0.05). Differential ruminal metabolites were predominantly enriched in pathways involving pantothenate and CoA biosynthesis, regulation of lipolysis in adipocytes, thermogenesis, and lysine degradation. Prevotellaceae_UCG-001 was negatively correlated with average daily feed intake (ADFI) and immunoglobulin M (IgM) (p < 0.05), and ascorbate radical and ureidoperacrylic acid showed significant correlations with ADFI, IgM, and Prevotellaceae_UCG-001 (p < 0.05). Both Anaerobispirillum and Quinella were negatively correlated with TNF-α (p < 0.05), whereas thiamine and zeatin showed positive correlations with TNF-α and Quinella (p < 0.05). Under the present experimental conditions, the optimal supplemental level of YSE was 400 mg/kg diet.

The Northwest Xizang White Cashmere goat has a high global reputation for good goat cashmere germplasm characteristics, and its cashmere industry is the economic pillar of the herdsmen in the northwest plateau of Xizang. Cashmere is produced by the secondary hair follicles of the skin, and the key period of hair follicle development is from birth to 3 months old. This study aimed to explore how early compound nutritional intervention affects lamb growth performance and secondary hair follicle development. We assessed skin follicle density and performed skin transcriptomic and multi-omics analyses to clarify this regulatory effect. The trial was performed at the Northwest Xizang White Cashmere Goat Breeding Farm, Ritu County, Ngari region, Xizang. Thirty newborn single lambs of comparable birth status were randomly divided into control and early compound nutritional intervention groups (n = 15 per group). The results showed that early compound nutritional intervention significantly increased the secondary hair follicle density, total hair follicle density, and secondary/primary hair follicle (S/P) value of lambs (p < 0.05). However, there was no significant difference in the average cashmere fineness between the two groups (p > 0.05). The transcriptome, proteome, and metabolomics analyses of the skin revealed candidate genes related to hair follicle development and the regulation of cashmere fineness: keratin structural genes (KRT10, KRT18, KRT26), cell proliferation and adhesion-related regulatory genes (ITGB2, CSF1R, AKT1), and extracellular matrix coding genes (COL6A1, COL6A2, COL6A6). Moreover, the results revealed that key proteins related to hair follicle development include RBP4, KAP13-3, KRTAP3-1, KRTAP27-1, DKK3, ITGB2, and DUSP23. The differentially expressed metabolites, 15-Deoxy-delta12,14-Prostaglandin J2 and Thromboxane B2 (TXB2), modulate prostaglandin-associated pathways; altered pathway activity subsequently regulates the expression of hair follicle functional genes and key proteins, which may in turn indirectly regulate hair follicle growth and development, thereby affecting hair follicle density and, by extension, cashmere production performance. Therefore, early compound nutritional intervention of Northwest Xizang White Cashmere goats promotes the growth and development of secondary hair follicles. The identified candidate genes and key proteins involved in secondary hair follicle development provide a reference for exploring the mechanism of hair follicle development.