Effects of wheat-based fermented liquid feed on growth performance, nutrient digestibility, gut microbiota, intestinal morphology, and barrier function in grower-finisher pigs

Fermented liquid feed (FLF) can improve dietary nutrient absorption levels, degrade antinutrient factors in diets, and increase beneficial bacteria abundance in animal guts. However, few systematic studies have been conducted on wheat-based fermented liquid feed (WFLF) in pigs. The present study evaluates the effects of WFLF on the growth performance, nutrient digestibility, gastric volume, intestinal morphology, intestinal health, intestinal barrier function, serum biochemical immunity, gut microbiota, and intestinal microbial diversity of grower-finisher pigs. In total, 80 weaned pigs were randomly allocated to two treatment groups based on their initial body weight: a basal diet with pellet dry feeding (CON) and a basal diet with WFLF, with four replicate pens per group. The experiment lasted 82 d. Compared with CON pigs, those fed WFLF were significantly heavier at 60 to 82 d and had significantly higher average daily feed intake, average daily gain, and gain: feed ratio at 60 to 82 d and 1 to 82 d. WFLF pigs had significantly greater jejunum, total tract, and ileal digestibility for all nutrients and amino acids, excluding arginine, than CON pigs. WFLF intake influenced villus height, villus height:crypt depth ratio of the anterior segment of the jejunum (A-jejunum), crypt depth, and redox potential of the posterior segment of the jejunum (P-jejunum) while significantly affecting body weight. Additionally, FLF improved gastric capacity significantly. Furthermore, mRNA expression of occludin and claudin-1 in the mucosa of the ileum and jejunum was significantly higher in WFLF pigs than in CON pigs. WFLF increased serum concentrations of alanine transaminase and reduced low-density lipoprotein cholesterol, total cholesterol, and total bile acid content. The alpha diversity (Shannon and Simpson indices) in the stomachs of WFLF pigs was significantly higher than in CON pigs. Microbial diversity in the stomach, ileum, and cecum, as well as the abundance of lactic acid bacteria, were increased in WFLF pigs compared to CON pigs. In conclusion, WFLF intake may positively influence intestinal ecology by improving digestive tract structure, upregulating intestinal barrier-related genes, and improving intestinal morphology to enhance intestinal digestive function and health. Collectively, the present study shows that WFLF intake can increase growth performance while maintaining beneficial nutrient digestibility in grower-finisher pigs. Wheat-based fermented liquid feed improves growth performance, nutrient digestibility, and gut health in grower-finisher pigs, offering a promising strategy for sustainable pork production. Our study investigated the effects of fermented liquid feed (FLF) on pig growth and health. FLF is prepared by mixing feed with water and allowing it to ferment, which can improve its nutritional value and digestibility. We found that pigs fed a wheat-based fermented liquid feed (WFLF) showed improved growth performance, including higher body weight and better feed efficiency, compared to those on traditional dry pellet diets. Additionally, WFLF enhanced the health of the pig intestines by increasing the abundance of beneficial bacteria, such as lactic acid bacteria, and reducing harmful bacteria like Escherichia coli. These changes in the gut bacterial community were accompanied by improvements in the intestinal structure and function, as well as better nutrient absorption. Our findings suggest that using WFLF as an alternative to conventional dry feed can promote both growth and intestinal health in pigs. This feeding strategy has the potential to be a cost-effective and sustainable approach in pig production. Graphical Abstract