Genomics and metabolomics of post-weaning return to estrus

Gut microbiota affects the estrus return of sows by regulating the metabolism of sex steroid hormones

BACKGROUND

Sex hormones play important roles in the estrus return of post-weaning sows. Previous studies have demonstrated a complex and bi-directional regulation between sex hormones and gut microbiota. However, the extent to which the gut microbiota affects estrus return of post-weaning sows is largely unknown.

RESULTS

In this study, we first screened 207 fecal samples from well-phenotyped sows by 16S rRNA gene sequencing and identified significant associations between microbes and estrus return of post-weaning sows. Using metagenomic sequencing data from 85 fecal samples, we identified 37 bacterial species that were significantly associated with estrus return. Normally returning sows were characterized by increased abundances of L. reuteri and P. copri and decreased abundances of B. fragilis, S. suis, and B. pseudolongum. The changes in gut microbial composition significantly altered the functional capacity of steroid hormone biosynthesis in the gut microbiome. The results were confirmed in a validation cohort. Significant changes in sex steroid hormones and related compounds were found between normal and non-return sows via metabolome analysis. An integrated analysis of differential bacterial species, metagenome, and fecal metabolome provided evidence that normal return-associated bacterial species L. reuteri and Prevotella spp. participated in the degradation of pregnenolone, progesterone, and testosterone, thereby promoting estrogen biosynthesis. Furthermore, the microbial metabolites related to sow energy and nutrient supply or metabolic disorders also showed relationships with sow estrus return.

CONCLUSIONS

An integrated analysis of differentially abundant bacterial species, metagenome, and fecal metabolome revealed the involvement of L. reuteri and Prevotella spp. in sow estrus return. These findings provide deep insight into the role of gut microbiota in the estrus return of post-weaning sows and the complex cross-talk between gut microbiota and sex hormones, suggesting that the manipulation of the gut microbiota could be an effective strategy to improve sow estrus return after weaning.

Soybean oil supplementation for sows in the first three days after farrowing

One of the main causes of death in newborn piglets is the low level of energy reserves to maintain their body temperature, which can lead to hypothermia and, subsequently, death. Thus, the objective of this study was to evaluate the effect of soybean oil supplementation to sows in the first three days after farrowing to save piglet fat reserves through the higher nutritional intake of sow milk. In total, 604.5, 750, 1000, 1250 and 1500 g of soybean oil were provided for each sow during the three days of supplementation. A total of 60 sows were evaluated per treatment, distributed in a random block design, supplemented in the first three days after farrowing with soybean oil added on top of the feed at the time of feeding. Performance and reproductive data and milk samples were collected from the sows to determine fat levels. Piglets were evaluated for fall-back rate and survival. There was no significant effect of soybean oil supplementation on any of the parameters evaluated for both sows and their milk. Therefore, soybean oil supplementation for sows in the first three days after farrowing does not influence performance parameters, reproduction and milk fat of the sows and mortality and fall-back rate of the piglets.