Diets Fermented with Bacteria and Enzymes in China Improve Growth Performance and Health of Weaned Piglets

Simple Summary Microbially fermented feed can improve the nutritional value and quality of the feed. Liquid feeding can increase feed intake and reduce the morbidity and mortality of piglets. Therefore, in this study, the integrated technology of a diet fermented with bacterial enzymes and liquid feeding was used to study its effects on the growth performance and intestinal health of weaned piglets. Compared with the control group (standard dry feed, control group), the diet of the liquid feeding group (liquid feeding group with fermented diet) was able to increase palatability, improve nutrient digestibility, and modulate metabolism, resulting in higher feed efficiency and better growth performance. The results of this study provide a reference for the development and utilization of antibiotic-free feed for weaned piglets. Microbial fermentation has been widely used to preserve or improve the nutritional properties of food. Liquid feeding can increase feed intake and reduce the morbidity of piglets. The objective of this study was to evaluate the effects of a diet fermented with bacteria and enzymes and liquid feeding on growth performance, nutrient digestibility, digestive enzyme activity, microflora, and expressions of intestinal development-related genes in weaning pigs. A total of 198 piglets (Duroc x Landrace x Yorkshire) with body weights of 8.70 +/- 0.45 kg were assigned to three groups with six replicates per treatment, and 11 weaned piglets per replicate according to the initial body weight and sex. The three dietary treatments (all nonpelleted diets) were a standard dry feed as the control (CON), a control diet supplemented with antibiotics (AB), and a liquid feeding with a fermented diet (LFD). The liquid feeding diet, having the same composition and proportion of each ingredient as the control diet, was prepared by storing the dietary cereals (corn, soybeans, etc.) and water (1:0.5, wt/wt) in a closed tank at 26-30 degrees C with enzymes and bacteria, and then adding the remaining dietary ingredients immediately before feeding. The whole trial lasted 42 days. On days 11 to 14 and 39 to 42, fresh faecal samples were collected to evaluate the apparent total tract digestibility of nutrients. Performance, digestibility, serum physiochemical parameters, intestinal barrier function, microbiota, and microbial metabolites were measured. The experimental data were subjected to analysis of variance using the GLM procedure of SAS for a complete randomized block design, with a "pen" as the experimental unit. The results showed that the AB increased (p < 0.05) average daily gain and reduced (p < 0.05) feed conversion (F/G) over the course of 1-14 days compared to the control. The liquid feeding group significantly increased (p < 0.05) average daily gain, average daily feed intake, and final body weight compared to the other two dietary groups. The digestibility of crude protein, ether extract, ash, gross energy, Ca, and P also improved in the liquid feeding group. Moreover, the liquid feeding group significantly decreased (p < 0.05) serum urea nitrogen and D-lactate concentrations, as well as the activity of diamine oxidase, and increased (p < 0.05) serum total protein and glucose concentrations on day 14. Furthermore, the liquid feeding group significantly increased (p < 0.05) mRNA expressions of zonula occludens-2 (ZO-2) in the jejunum and zonula occludens-1 (ZO-1), ZO-2, occludin, and claudin-1 in the ileum. In addition, microbiota measurement suggested an increase in Lactobacillus content and a decrease in Escherichia coli with higher (p < 0.05) concentrations of acetic acid, propionic acid, butyric acid, and total volatile fatty acids in the caecal and colonic digesta of piglets in the liquid feeding group. In conclusion, the diet in the liquid feeding group was able to increase palatability, improve nutrient digestibility, and modulate metabolism, which resulted in higher feed efficiency and better growth performance in the piglets.