Effects of Supplemented Resveratrol on In Vitro Ruminal Fermentation and Growth Performance of Hanwoo Calves

Simple Summary Recently, probiotics and plant extracts have been used as alternatives to antibiotics in livestock systems. Extracts of various plants have been shown to enhance digestion, increase intestinal immunity, and affect nutrient utilization and metabolism in ruminants. However, the physiological effects of plant extracts are diverse and complex, and the exact underlying mechanism has not yet been elucidated. Resveratrol is a polyphenolic substance produced when plants are exposed to adverse environments, such as fungi and pests. It has antitoxic properties that constitute plant self-defense and antioxidant properties that inhibit fatty acid oxidation. Although the metabolism of resveratrol in the rumen is unknown, resveratrol and its metabolites may play an important role in manipulating rumen bacteria. We show that feeding resveratrol to ruminants affects their digestion and immunity. The health and immunity of young ruminants can affect disease pathogenesis and long-term fattening. We believe that healthy calves could grow stably without losing energy due to disease, which would improve their growth and boost their immunity. We investigated the effects of resveratrol supplementation on in vitro ruminal fermentation and growth performance of Hanwoo calves. Treatment with three resveratrol concentrations (0%, 0.1%, 0.3%, and 0.5%) was used for in vitro ruminal fermentation. Resveratrol concentrations and pH of rumen fluid were negatively correlated (p < 0.05); therefore, total gas production, total volatile fatty acids, and acetate, propionate, and butyrate levels were significantly higher in the treatments than in the control at all time periods (p < 0.05). The appropriate resveratrol concentration that could be added without negative effects on the rumen was 0.3%. In farm experiments, we divided 14 Korean cattle calves into control (C) and 0.3% resveratrol (T) groups. There were no significant differences in the daily weight gain, feed conversion, final body weight, body length, withers height, and height at hip cross in the resveratrol-fed Hanwoo calves. Immunoglobulin G level was significantly higher in the treatment than in the control (p < 0.05), but IgA and IgM levels did not differ. Supplemental feeding of resveratrol is beneficial to in vitro ruminal fermentation, but it is important to supplement it at 0.3%. Furthermore, resveratrol affects calf immunoglobulin G.