Long-term storage (1–4 years) maintains nutritional value of wheat for geese: Metabolic energy and nutrient utilization

We evaluated the nutritional value of wheat stored for 1-4 years in geese through metabolic trials, focusing on metabolizable energy (AME and TME), nutrient composition, amino acid (AA)utilization, and non-starch polysaccharides (NSP). A randomized experiment utilized 24 healthy adult male geese (aged 280 days, 4.31 ± 0.25 kg), evenly divided into four groups (six replicates per group, one goose per replicate). Wheat samples of the same variety, origin, and planting method were collected, representing storage durations of 1, 2, 3, and 4 years. Wheat stored for 1-4 years maintained consistently high levels of gross energy (GE), crude protein (CP), AA, and starch, and no mycotoxins were detected. The dry matter, GE, CP, crude fat, total phosphorus, starch, and AA contents remained stable across storage years (CV < 5 %). In contrast, acid detergent fiber (ADF), neutral detergent fiber (NDF), mannan, and β-glucan exhibited significant variations (CV > 5 %). Notably, geese's utilization efficiency of mannan, β-glucan, hemicellulose, ADF, NDF, and starch improved linearly with longer storage periods (P < 0.05). The apparent metabolizable energy (AME) values for 1-, 2-, 3-, and 4-year-old wheat were 14.12, 14.45, 15.34, and 13.59 MJ/kg (mean: 14.38 MJ/kg), while true metabolizable energy (TME) values were 15.35, 15.54, 16.40, and 14.76 MJ/kg (mean: 15.51 MJ/kg). AME and TME peaked at 3 years of storage but declined at 4 years. In conclusion, wheat without mycotoxin contamination retained nutritional suitability for geese during 1-4 years storage, although a reduction in nutritional value was observed after 4 years.