Nutritive value of buffelgrass-based diets supplemented with dried distillers grains with solubles and dried citrus pulp

Abstract Text: The objective of the study was to evaluate the effect of supplementing small amounts of dried distillers grains with solubles (DDGS) or dried citrus pulp (DCP) upon the nutritive value of buffelgrass (Cenchrus ciliaris L)-based diets. Twelve experimental diets were formulated using three qualities of buffelgrass: low (3.0% CP, 70% NDF), medium (5.6% CP, 66.5% NDF) and high quality (12.4% CP, 60.8% NDF) and four levels of supplementation (0%, 10% DCP, 10% 50DCP:50DDGS, and 10% DDGS). Utilized DCP and DDGS contained 3.8% and 30.6% CP, respectively. Sample contents of ash, crude protein (CP, Leco), neutral detergent fiber (NDF), hemicellulose, cellulose, lignin, and ether extract (EE) were determined. The in vitro dry matter digestibility (IVDMD; Daisy^II, ANKOM), and in vitro gas production (GP) at 0, 3, 6, 9, 12, 24, 48, 72 and 96 h were measured, and fermentation parameters a, b, and c were calculated. Metabolizable energy (ME) content was calculated from the gas production, protein and ether extract content. Each treatment was replicated four times, and results were evaluated according to a 3 x 4 factorial arrangement of treatments, using SPSS software. There were no significant (P>0.05) grass quality x supplement interactions. Ash and protein contents were respectively 30% and 70% less for low- than for high-quality buffelgrass-based diets. Diets made up of high quality buffelgrass had 14% less NDF content, 7% lower hemicellulose, 19% less cellulose and 29% lower lignin content than diets based on low quality buffelgrass (68.1% NDF, 30.9% hemicellulose, 32.5% cellulose, and 4.7% lignin, DM basis). IVDMD was 81.8% for high quality-, and 67.2% for low quality-buffelgrass-based diets, and inversely correlated (r:-0.832; P<0.001) with NDF content. ME content of diets was 26% higher (P<0.05) in high quality-, than in the low quality-grass based diets (1424 Kcal ME/ kg DM). Addition of DDGS increased (P<0.05) 28% the ether extract and 34% the protein content of buffelgrass. Addition of DCP and DDGS to the diet increased in average 5.5% (P<0.05) the IVDMD of non-supplemented buffelgrass (72.5%). In vitro fermentation parameters a, b, and cwere neither affected by grass quality nor by type of supplement (P>0.05). In conclusion, quality of buffelgrass determined the nutritive value of diets; supplementing DDGS increased protein and fat content and DCP improved IVDMD.

Keywords: buffelgrass, dried citrus pulp, dried distillers grains with solubles