The objective of this experiment was to determine whether the dietary inclusion of fermented corn gluten meal (FCGM) would alter the growth, rumen fermentation and plasma metabolites of postweaning calves. Twenty-four Holstein male calves (mean ± SEM: ages = 56.21 ± 2.43 d; body weight = 83.36 ± 3.62 kg) were kept in individual pens (2.0 × 2.5 m2). After 2 weeks of adaptation, the calves were blocked for body weight and age before being randomly assigned to 1 of 2 diets groups (12 calves per group): (1) untreated basal diet (Control diet, CON), and (2) supplementation with 5% of FCGM in the basal diet (FCGM diet, FCGM, DM basis). Diets were isoenergetic and isonitrogenous as well as the amino acids levels were similar between 2 diets. Moreover, the calves received diets and water ad libitum throughout the 8 week trial period. Calves fed FCGM diet significantly increased the average daily gain (P = 0.028) and feed efficiency (P = 0.034) and tended to elevate withers height (P = 0.067) compared with the CON. No difference was observed for body weight, body length and heart girth between the treatments. The rumen ammonia nitrogen (P < 0.001), acetate (P = 0.004), propionate (P = 0.042), total volatile fatty acids (P = 0.002), microbial protein (P = 0.003) and proteinase (P = 0.001) were higher in FCGM calves. Moreover, rumen pH (P < 0.001) was lower in FCGM. The relative abundance of the phylum-level Bacteroidetes (79.4%) and the family-level Prevotellaceae (56.1%) in FCGM was higher than that in CON (66.8% and 37.7%, respectively). Feeding FCGM significantly increased the relative abundance of the genera-level Prevotella_1 (P = 0.028) and Prevotellaceae_UCG-003 (P = 0.016) but decreased the relative abundance of the Ruminobacter (P = 0.011) compared with the CON. Additionally, FCGM significantly increased the plasma total protein (P = 0.027), glucose (P = 0.014), total superoxide dismutase (P = 0.003), catalase (P = 0.023), total antioxidant capacity (P = 0.029), immunoglobulin A (P = 0.016), immunoglobulin G (P = 0.026), growth hormone (P = 0.027) and insulin-like growth factor-І (P = 0.007). In conclusion, the dietary inclusion of FCGM elevated the growth rate and feed efficiency, promoted rumen fermentation, diversified the bacterial community composition in the rumen, as well as improved antioxidant and immune functions of calves during the postweaning stage.
Read full abstract