Effect of bran and lactic acid bacteria preparation on silage quality and nutrient content of a tea residue

This experiment was conducted to investigate the effect of different bran contents and lactic acid bacteria concentrations on silage quality and nutrient content of a tea residue. Four different concentrations of lactic acid bacteria in a preparation (0, 50, 100, and 200 mg·kg^–1) were added to five tea residue materials with different bran contents (0, 5%, 10%, 15%, and 20%). Silage quality and nutrient content were measured after 45 days. The results showed that compared with tea residue silage alone, adding bran increased ammonia/total nitrogen ratio, and contents of lactic acid, acetic acid, dry matter, and ash significantly (P < 0.05), and reduced pH, concentration of crude protein, acid detergent fiber, and tea tannin of silage tea residue significantly (P < 0.05). Adding the lactic acid bacteria preparation reduced pH, ammonia/total nitrogen ratio, and contents of acetic acid, dry matter, and acid detergent fiber significantly (P < 0.05), and increased the contents of lactic acid, crude protein, crude ash, and tea tannin of silage tea residue significantly (P < 0.05). Among them, pH of the silage tea residue with 15% and 20% bran was significantly lower than that of other groups (P < 0.05); the ammonia/total nitrogen ratio and acetic acid content of tea residue with 100 mg·kg^–1 lactic acid bacteria were significantly lower than those of other groups (P < 0.05), and the ash content was significantly higher than those of other groups (P < 0.05). In summary, addition of bran and a lactic acid bacteria preparation to the tea residue improved the palatability, silage quality, and nutrient content of the silage tea residue significantly; in terms of silage quality, 100 mg·kg^–1 lactic acid bacteria preparation added to the mixture of 85% tea residue +15% bran resulted in better quality of silage tea residue feed.