Effects of Dietary Fiber Fermentation and Protein Digestion Properties on Growth Performance and Microbial Metabolites in Weaned Pigs.

Dietary nutrient digestion and utilization patterns influence pig performance and intestinal health. This study aimed to evaluate the effects of protein digestion and fiber fermentation speed among different feed ingredients on growth performance and fecal short-chain fatty acid (SCFA) concentrations in weaned pigs. A total of 192 weaned pigs (Duroc × Landrace × Yorkshire [6.87 ± 0.14 kg]) were selected and randomly divided into four dietary groups: fast-digesting protein with fast-fermenting fiber, fast-digesting protein with slow-fermenting fiber, slow-digesting protein with fast-fermenting fiber, and slow-digesting protein with slow-fermenting fiber. The results showed that cottonseed and wheat protein powders exhibited faster protein digestion than potato protein powder (p < 0.05). In vitro microbial fermentation of hawthorn powder and orange pomace resulted in greater and faster gas production and SCFA concentrations than sugarcane bagasse (p < 0.05). Orange pomace increased the abundance of Klebsiella and Escherichia-Shigella, whereas sugarcane bagasse increased the abundance of Rikenellaceae_RC9_gut_group and norank_f__Muribaculaceae. In addition, the fast-fermentation fiber tended to increase the daily weight gain and feed intake of piglets (p < 0.10), and the slow-fermentation fiber significantly reduced diarrhea incidence in pigs (p < 0.05). Fast fermentation increased acetate and valerate concentrations, and slow-digestion protein increased branched-chain SCFA and valerate contents (p < 0.05). In conclusion, there were large variations in protein digestion and fiber fermentation speed among the different common feed ingredients. Dietary protein digestion and fiber fermentation speed would affect growth performance and diarrhea incidence in weaned pigs.