Chemical composition and fermentative characteristics of elephant grass silages with increasing levels of soursop by-product

Abstract

The experiment was carried out at the Forrage Research Sector, with the aim to evaluate the nutritive value and fermentative characteristics of elephant grass silages by adding soursop by-product (SB). 20 experimental silos of polyvinyl chloride (100 x 340 mm) were used in a completely ramdomized design with five addition levels (0; 5; 10; 15 e 20%, in a fresh matter basis) of SB and four replicates. After 32 days of ensiling, samples were collected to determine the dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, ethereal extract (EE), ammonia (N-NH3) levels and the pH values. The DM (P<0,05) and CP (P<0,05) levels were raised in 0.80 and 0.14 percent units for each 1% of SB, respectively. The NDF (P>0,05) levels showed the medium value of 68.13% while ADF (P<0,05) levels were raised in 0.18 percent units for each 1% of SB addition. The EE (P<0,05) level changed from 4.46 to 16.60% between silages with 0 and 20%, respectively. The silages N-NH3 (P>0,05) levels stayed below the limit of 12%, averaging 9.50%, and the pH (P>0,05) values remained within the ideal range of pH considered for well-kept silages (3.8 - 4.2). The SB addition improved the nutritive value of the silages, keeping their fermentative patterns. However, the higher contents of EE indicate that the inclusion of SB on elephant grass ensiling must be up to the level of 2.63%, in a fresh matter basis.