Purslane supplementation improved antioxidant capacity and milk quality potentially through rumen microbiota in dairy goats.

Purslane is a common plant with medicinal and edible homology that displays potential as a dietary supplement. In this study, this experiment aimed to investigate the effects of purslane on the health and milk quality of dairy goats in peak-lactation period. Twenty primiparous goats with similar days in milk (90 ± 10 d) and milk yield (1.54 ± 0.10 kg/d) were randomly divided into two treatments, each consisting of 10 replicates with one goat per replicate. The goats were fed with a basal diet supplemented with or without 2.5% purslane. After eight weeks, milk samples were collected for milk composition and biochemical analysis. Serum samples were obtained to identify serum parameters. Rumen fluid was collected for 16S rRNA sequencing. The metabolome of rumen fluid and serum was analyzed via untargeted metabolomics. The results showed that compared to the control, purslane decreased the relative abundance of harmful bacteria in the rumen, including [Eubacterium]_ruminantium_group and Butyrivibrio (P < 0.05); ruminal concentrations of propionate, isobutyrate, butyrate, isovalerate, and valerate were greater in goats fed with purslane (P < 0.05); purslane markedly enhanced antioxidant capacity, which was evidenced by the increased activities of serum antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) (P < 0.05). Also, nontargeted metabolomic analysis revealed that purslane increased serum metabolites involved in glycolipid metabolism, which were associated with the enhanced anti-inflammatory system (P < 0.05). Meanwhile, purslane increased immunoglobulin M (IgM) content and up-regulated beneficial metabolites in milk, such as flindersine, pyruvate, and didymin (P < 0.05). Correlation analysis further revealed that the relative abundance of ruminal Firmicutes, [Eubacterium]_ruminantium_group, and Butyrivibrio had negative relationships with serum SOD, GSH-Px activities and milk IgM content (P < 0.05). More importantly, linalool oxide, a component of purslane, was released into milk, which is considered as a potential anti-inflammatory compound. In conclusion, this study demonstrated that purslane improved antioxidant capacity and milk immunoglobulins in dairy goats, which may be associated with the modulation of ruminal microbiota.