Effects of feeding high-moisture corn on growth performance, serum biochemistry, and serum metabolomics in Simmental crossbred bulls

This study aimed to investigate the effects of replacing cracked corn with different proportions of high‑moisture corn (HMC) on the growth performance, serum biochemistry, and serum metabolomics of Simmental crossbred bulls.Thirty-two bulls were randomly assigned to four dietary treatment groups, where cracked corn was substituted with high-moisture corn (HMC) at inclusion rates of 0 % (CT), 15 % (T1), 30 % (T2), and 45 % (T3) on an equal-weight basis. The experiment lasted 120 days. Compared with the CT group, all HMC‑supplemented groups showed increased average daily gain (ADG) and average daily feed intake (ADFI). The T3 group (45 % HMC) exhibited the most pronounced improvement, with final body weight and ADG being significantly higher than those of the other groups ( P < 0.05). Serum biochemical analysis indicated that the T3 group had significantly elevated levels of immunoglobulins (IgA, IgM, IgG), growth hormone, and insulin‑like growth factor‑1 ( P < 0.05). Metabolomics analysis further revealed that HMC supplementation significantly affected lipid‑related pathways, including glycerophospholipid metabolism and linoleic acid metabolism. Key lipid metabolites such as phosphatidylethanolamine, phosphatidylcholine, and triglycerides were markedly up‑regulated ( P < 0.01). In conclusion, feeding HMC at a 45 % substitution rate effectively promoted growth, enhanced immune function, and modulated lipid metabolism pathways in Simmental crossbred bulls.