Psyllium and Inulin Supplementation Alleviates Diarrhea and Supports Gut Flora in PreWeaning Calves

Pre-weaning diets are critical to the intestinal health of calves, and dietary fiber is considered to regulate gut microbiota and enhance gastrointestinal conditions.However, the effects of different types of dietary fibers vary significantly, and the specific impacts on the intestinal microbiota of neonatal calves remain largely unexplored.This study investigates the effects of supplemental psyllium husk powder and inulin on growth performance, diarrhea prevention, and fecal microbiota composition in calves.A total of 136 healthy newborn Holstein calves were randomly assigned to one of three groups: control, psyllium husk, and inulin groups, with the experimental groups receiving a fiber supplementation of 0.2 g/kg body weight from birth until weaning.The daily mixed feed was added to milk and evenly divided into two to three feedings.Key parameters assessed included average daily gain (ADG), starter intake post-56 days, and diarrhea status.To better evaluate the effects of dietary fiber, calves that remained diarrhea-free throughout the study period were selected, with fecal samples collected from the same calves at age 0, 7, 14, 28, and 56 days.Results showed that psyllium husk and inulin supplementation significantly reduced the incidence and duration of diarrhea, promoted the growth of beneficial flora, especially acid-producing bacteria, and decreased the relative abundance of Dorea during the peak diarrhea period.By the end of the pre-weaning phase, both fibers increased the relative abundance of Prevotella, contributing to improved gastrointestinal health in calves.This study suggests that psyllium husk and inulin supplementation may offer a viable nutritional intervention strategy to enhance gut microbiota composition and health outcomes in pre-weaning calves.