Effects of whole cotton seed on plasma metabolism and lactation performance of sheep

Whole cottonseed (WCS), a major by-product of cotton ginning, is rich in protein and energy, yet its effects on perinatal ewes remain underexplored. This study aimed to assess the impact of WCS supplementation on the lactation performance, milk composition, plasma antioxidant capacity of perinatal Hu ewes, and the growth performance of their lambs, providing insights into the potential application of WCS in Hu ewes production. The experiment lasted 56 days, comprising a 7-day adaptation period followed by a 49-day experimental phase (21 days prepartum and 28 days postpartum). Forty-four healthy perinatal Hu ewes, with an average body weight of 45.67 ± 5.12 kg (mean ± SD) and similar expected lambing dates, were selected and randomly assigned to two groups (22 ewes per group): the control group (basal diet) and the experimental group (basal diet supplemented with 200 g WCS/d). Data were analyzed using independent samples t-tests, while metabolomics data were subjected to partial least squares-discriminant analysis (PLS-DA) and KEGG pathway enrichment. The results demonstrated that the milk protein percentage on day 21 was significantly higher in the trial group compared to the control group (p < 0.05). WCS supplementation notably increased lamb body weight at 14 and 28 days of age (p < 0.05), as well as the average daily gain from days 1 to 14 and days 1 to 28 (p < 0.05). Additionally, WCS supplementation significantly elevated albumin (ALB) levels in Hu ewes on day 28 postpartum (p < 0.05). Plasma antioxidant capacity was significantly enhanced (p < 0.01), alongside increased activities of catalase, superoxide dismutase, glutathione peroxidase, and nitric oxide concentration, while malondialdehyde levels were reduced, though not significantly (p > 0.05). Milk protein percentage was 6.2% higher (p < 0.05), T-AOC, CAT, SOD, and GSH-Px increased by 15–25% (p < 0.01). In conclusion, supplementing perinatal Hu ewes with WCS effectively improved their antioxidant capacity, lactation performance, and milk composition, which in turn promoted lamb growth. Supplementation with 200 g/d WCS was associated with improvements in antioxidant capacity, lactation performance, and lamb growth. Untargeted metabolomics further suggested that these improvements might be linked to enhanced lipid utilization, altered purine metabolism, and modulation of sphingolipid signaling, highlighting the molecular basis behind the nutritional effects.