Optimizing additive combinations to improve peanut vine silage fermentation quality and feed efficiency for...

Peanut vine is a widely available agricultural by-product with high nutritional value, but its utilization is limited by poor ensiling characteristics. The purpose of this study was to improve the fermentation quality of peanut vine silage by using lactic acid bacteria (LAB), compound enzymes, and molasses both separately and in combination, and to evaluate their effects on growth performance and metabolic indicators in fattening Hu sheep.

Peanut vine was treated with different levels of LAB, enzymes, and molasses to determine optimal dosages. The optimal combination of 2 g/t LAB, 200 mL/t enzyme preparation, and 10 kg/t molasses was identified based on fermentation characteristics. Treatments included a control (no additive), single additives, and the combined treatment. After 60 d of ensiling, silage pH, lactic acid, ammonia-N, fiber degradation, and bacterial community structure were analyzed. A 56 d feeding trial was subsequently conducted with 56 Hu sheep (28.4±1.3 kg), randomly assigned to two groups: peanut vine hay and peanut vine silage. Growth performance and serum biochemical parameters were assessed.

The optimal additive combination significantly improved fermentation by reducing pH (from 4.74 to 4.36), ammonia-N/total nitrogen (from 2.82% to 1.50% dry matter [DM]) and detergent fiber contents (neutral detergent fiber from 43.9% to 41.3% and acid detergent fiber from 34.6% to 32.2%), while increasing lactic acid concentration (from 3.55% to 5.00% DM). Microbial analysis revealed a higher relative abundance of Lactobacillus plantarum and increased microbial diversity. In the animal trial, no significant differences were found in average daily gain, DM intake, or feed conversion ratio between groups. However, sheep fed silage showed lower blood urea nitrogen and higher serum triglyceride concentrations, indicating improved nitrogen and lipid metabolism.

Peanut vine silage treated with LAB, enzymes, and molasses improves fermentation quality and supports comparable growth performance to hay while improving nutrient metabolism in fattening Hu sheep. This approach provides a sustainable strategy for converting legume crop residues into valuable ruminant feed.