Early gestation selenium supplementation enhances litter size and sow reproductive health

Embryonic loss during early gestation is a major constraint on sow reproductive performance. Selenium yeast may improve embryo survival by enhancing antioxidant defences, reducing oxidative stress, and modulating the gut microbiota.

Objective: This study evaluated the effects of selenium yeast supplementation during early gestation in Landrace × Yorkshire sows.

Method: Eighty-eight multiparous sows were allocated to either a control diet (0.27 mg Se/kg; n = 45) or the same diet supplemented with selenium yeast (0.40 mg Se/kg total Se; n = 43) from 7 days before mating until day 21 of gestation. Blood samples were collected on gestation days 14, 21, and 28, while faecal samples were collected on gestation days 14, 21, and 107, and lactation days 7 and 21. Faecal microbiota was analysed by full-length 16S rRNA sequencing, and untargeted metabolomics was performed on faecal and serum samples.

Results: Selenium yeast supplementation during early gestation improved sow reproductive performance, increasing litter size and enhancing the number and total weight of piglets at 21 days of lactation. The supplementation also improved maternal physiological status by increasing serum progesterone levels and antioxidant capacity, with higher activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT), together with reduced oxidative stress markers. Selenium yeast supplementation modulated the gut microbiota composition, increasing microbial diversity and promoting beneficial bacteria such as Limosilactobacillus, Lactobacillus, L. amylovorus, L. reuteri, and L. johnsonii. It also altered intestinal and serum metabolic profiles, particularly pathways related to steroid hormone biosynthesis. The supplementation increased short-chain fatty acid production, especially butyric acid, which was positively associated with progesterone levels, antioxidant status, litter size, and total litter birth weight.

Conclusion: Overall, these findings suggest that selenium yeast supplementation during early gestation improves sow reproductive efficiency through coordinated effects on antioxidant capacity, hormonal regulation, gut microbiota, and metabolism.