Effects of Clostridium butyricum on Growth Performance, Health Status, and Metabolic Response of Pre-Weaning Angus Calves

This study investigated the effects of <i>Clostridium butyricum</i> (<i>C. butyricum</i>) supplementation on the bacterial community composition and fermentation characteristics of the digestive system, assessed blood antioxidant capacity, and evaluated growth performance and digestibility in pre-weaning Angus calves. Sixteen male Angus calves were randomly divided into two groups (<i>n</i> = 8). The control group was fed a basal diet, while the other group was supplemented with 2 × 10⁷ colony-forming unit/d <i>C. butyricum</i> in the basal diet. After 8 weeks of feeding, body growth and nutrient intake were measured. Rumen fluid samples, blood samples, and fecal samples were collected and analyzed. Fecal scores were recorded daily, and the frequency of diarrhea treatments was documented. The results showed <i>C. butyricum</i> supplementation improved the digestibility of neutral detergent fiber, crude protein, and ether extract in calves, as well as the growth hormone content in the blood. Furthermore, supplementation elevated isovaleric acid concentrations in the rumen, modulated the microbiome, and increased pre-weaning body weight and average daily gain of calves. Meanwhile, <i>C. butyricum</i> supplementation reduced myeloperoxidase and superoxide dismutase levels while increasing total antioxidant capacity in the blood, alleviating oxidative stress, and enhancing the antioxidant capacity of the body. Intestinal health was also improved, as evidenced by an increase in butyrate content, a reduction in <i>enterotoxigenic Escherichia coli</i>, lower fecal scores, and a decreased need for diarrhea treatments. In summary, dietary <i>C. butyricum</i> supplementation may support digestive system development, enhance antioxidant capacity, and improve growth performance and health status in pre-weaning Angus calves.