Influence of partial replacement of corn by crude glycerin on water consumption, feed intake and nutrient apparent digestibility

Abstract Text: Glycerin is a co-product from biodiesel production and it can improve energy efficiency when replaces corn. Five Dorper x Santa Inês ram lambs (BW 59.7 ± 1.3 kg), cannulated in the rumen, were used in a 5 X 5 Latin Square design to determine the effects of partial replacement of corn by crude glycerin (CG) on water consumption, feed intake and nutrient apparent digestibility. Animals were fed a total mix ration composed of 90% concentrate and 10% coastcross hay. The diets were isonitrogenous (15.9 ± 0.2 CP, DM basis) and the crude protein content was adjusted by increasing soybean meal. Crude glycerin (83.6% glycerol, DM basis) was included in the ration at 0, 5, 10, 15 or 20% (DM basis), corresponding to the experimental diets G0, G5, G10, G15 and G20, respectively. The diet was fed ad libitum, once daily. Every experimental period lasted 19 d. The first 15 d were used to adapt the lambs with the diets and the remaining 4 d were used to determine daily feed intake, water consumption and fecal output. For total collection of feces, harnesses with collection bags were used to avoid contamination of feces by urine. Data were analyzed using the MIXED procedure (SAS Inst. Inc.) and the LSMEANS option was used to generate individual means. Orthogonal polynomials for diet responses were determined by linear, quadratic or cubic effects. CG did not affect (P > 0.05) water consumption (4.77, 5.02, 5.01, 5.25, 4.56 L/d), dry matter (1.56, 1.51, 1.45, 1.43, 1.47 kg/d), crude protein (0.25, 0.25, 0.24, 0.22, 0.23 kg/d) and organic matter intakes (1.48, 1.43, 1.36, 1.33, 1.38 kg/d). Crude glycerin decreased (P < 0.01) NDF intake (0.29, 0.28, 0.24, 0.22, 0.24 kg/d) and increased (P < 0.01) mineral matter intake (0.08, 0.08, 0.09, 0.09, 0.10 kg/d). There was no effect on NDF (55.9, 54.5, 56.3, 56.7, 58.0%) and crude protein digestibilities (82.4, 81.7, 82.8, 81.5, 83.6%), However, DM (83.3, 82.5, 84.2, 85.4, 85.7%) and OM (84.8, 84.0, 85.9, 86.5, 86.8%) digestibilities showed a linear increase (P < 0.01). Crude glycerin can replace corn up to 20% of dietary DM increasing DM and OM apparent digestibilities.

Keywords: Glycerol, sheep, biodiesel