Silymarin Modulates Microbiota in the Gut to Improve the Health of Sow from Late Gestation to Lactation

SIMPLE SUMMARY: The gut microbiome is crucial for lactation sow health and production. This study aimed to investigate the effect of dietary silymarin supplementation on the inflammatory responses and fecal microbiota in lactation sow and to evaluate the relationship between the inflammatory factor and fecal microbiota in lactation sow. It is suggested in our results that silymarin supplementation decreased inflammatory responses of lactation sow and changed fecal microbiota composition at different taxonomic levels. The altered fecal microbiota was associated with variations in inflammatory factors, indicating that silymarin modulates microbiota in the gut and may improve the health of lactation sow. ABSTRACT: Inflammatory responses reduce milk production in lactating sows. Silymarin may modulate inflammatory reactions. Here, we aimed to verify whether dietary silymarin supplementation could alleviate inflammatory responses in lactating sows through microbiota change in the gut. We also investigated how silymarin impacts inflammatory response in lactating sows. One hundred and ten sows were randomly assigned to a control diet (basal diet) or treatment diet (basal diet and 40 g/d silymarin) from the 108th day of gestation to weaning. Blood, milk, and feces from sows were collected for analysis. It was shown in the results that dietary silymarin supplementation decreased the level of pro-inflammatory cytokine IL-1β (p < 0.05) on the 18th day of lactation in the blood of the sows. Dietary silymarin supplementation tended to decrease (p = 0.06) somatic cell count in the colostrum of sows. Dietary silymarin supplementation reduced the gut bacterial community and the richness of the gut microbial community (p < 0.01) using 16S rRNA gene sequencing. The fecal microbes varied at different taxonomic levels in the lactating sows with silymarin supplementation. The most representative changes included an increase in the relative abundance of Fibrobacteres and Actinobacteria (p < 0.05) and tended to reduce the relative abundance of Spirochaetaes and Tenericutes (p = 0.09, 0.06) at the phylum level. It is suggested that dietary silymarin supplementation in late gestation until lactation has anti-inflammatory effects in lactation sow, which could be associated with the modulation of gut microbiota.