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Effect of tannins on grass silage composition
Andrej Lavrečić
Alenka Levart
Sažetak
Fresh meadow grass was ensiled with chestnut tannin extract (Farmatan 75®, Tanin Sevnica, Slovenia) at concentrations of 0 (control), 3, 15 and 30 g of extract/kg of ensiling material. Addition of tannins to the fresh grass material did not change substantially the dry matter (DM), ether extract and neutral detergent fibre (NDF) contents of silages. The crude fibre content decreased (P < 0.05) and nitrogen-free extracts increased (P < 0.05) with the increasing amounts of added chestnut extract. The crude protein (CP) content decreased from 133 in control silage to 116 and 117 g/kg DM (P < 0.05) in silages prepared with 15 and 30 g of chestnut extract/kg of ensiling material, respectively. Silages prepared with increasing amounts of chestnut tannin extract had greater amounts (from 11.2 to 13.6 g N in true protein/kg DM in control silage and silage prepared with 30 g of chestnut extract/kg of fresh grass, respectively) and proportion of N in true protein (TrueN) (from 52.3 to 72.5 % of N in control silage and silage prepared with 30 g of chestnut extract/kg of fresh grass, respectively). On the contrary, the amounts of soluble N (SolN) decreased significantly (P < 0.05) with increasing amounts of chestnut tannin extract from 8.9 to 3.0 and 2.9 g N/kg DM in control silage and silages prepared with 15 and 30 g of chestnut extract/kg of fresh grass, respectively. In accordance with the above mentioned trends, the proportions of SolN in total CP contents also decreased (P < 0.05) from 43.7 to 15.7 % in control silage and silage prepared with 15 g of chestnut extract/kg of ensiling material, respectively. Increasing the amounts of chestnut extract in silages also decreased the amounts of ammonia-N in silages. The addition of chestnut tannin extract did not influence pH values of silages. The highest amounts of added chestnut tannin extract (15 and 30 g/kg of fresh grass) significantly (P < 0.05) decreased lactic acid content (from 101 to 81 g/kg DM in control silage and silages with 15 and 30 g of chestnut extract/kg of fresh grass, respectively). On the contrary, the amounts of acetic, propionic and butyric acid did not change significantly. Obtained results suggest that tannins can be successfully used as silage additives, with favorable effects on protein solubility and true protein contents.
Ključne riječi
Hrčak ID:
4496
URI
Datum izdavanja:
1.6.2006.
Posjeta: 2.245 *