Dietary Fiber during Gestation Improves Lactational Feed Intake of Sows by Modulating Gut Microbiota

Abstract Background The feed intake of sows during lactation is often lower than their needs. High-fiber feed is usually used during gestation to increase the voluntary feed intake of sows during lactation. However, the mechanism underlying the effect of bulky diets on the appetites of sows during lactation have not been fully clarified. The current study was conducted to determine whether a high-fiber diet during gestation improves lactational feed intake (LFI) of sows by modulating gut microbiota. Methods We selected an appropriate high-fiber diet during gestation and utilized the fecal microbial transplantation (FMT) method to conduct research on the role of the gut microbiota in feed intake regulation of sows during lactation, as follows: high-fiber (HF) diet during gestation (n = 23); low-fiber (LF) diet during gestation (n = 23); and low-fiber diet + HF-FMT (LFM) during gestation (n = 23). Results Sows in the HF and LFM groups had a higher LFI and litter weight of piglets at weaning, while the sows also had higher peptide tyrosine tyrosine and glucagon-like peptide 1 on day 110 of gestation (G110d) and day 7 of lactation (L7d). Sows given an HF diet had lower Proteobacteria, especially Escherichia-Shigella, on G110d and higher Lactobacilli, especially Lactobacillus_mucosae_LM1 and Lactobacillus_ amylovorus, on L7d. The enrichment of Escherichia-Shigella was alleviated by HF-FMT. In addition, HF and HF-FMT both decreased the perinatal concentrations of proinflammatory factors, such as endotoxin (ET), lipocalin-2 (LCN-2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). The concentration of ET and LCN-2 and the abundance of Proteobacteria and Escherichia-Shigella were negatively correlated with the LFI of sows. Conclusion The excessive enrichment of Proteobacteria, especially Escherichia-Shigella late in gestation, led to increased endotoxin levels, which result in inflammatory responses and adverse effects on the LFI of sows. Adding HF during gestation reverses this process by increasing the abundance of Lactobacilli, especially Lactobacillus_mucosae_LM1 and Lactobacillus_amylovorus.