Effects of waste vinegar residue on nutrient digestibility and nitrogen balance in laying hens

The aim of this study was to evaluate apparent metabolizable energy (AME) of waste vinegar residue (WVR) and to evaluate the effects of WVR on nutrient digestibility and nitrogen excretion in laying hens. In the first experiment the AME value and the nitrogen-corrected apparent metabolizable energy (AMEn) of WVR were studied by feeding hens 0, 100, 150, or 200 g/kg WVR. In the second experiment, 96 38-wk-old Hy-line laying hens were divided into four treatment groups, fed corn-soybean meal-based diets with 0, 20, 40, and 60 g/kg WVR, and nutrient digestibility and nitrogen excretion were measured. Regression analysis revealed that the AME and AMEn value of the WVR were 650 kcal/kg and 716 kcal/kg respectively. Diet including 40 g/kg WVR increased total tract apparent digestibilities (TTADs) of nitrogen (P=0.006) of hens. Inclusion of 60 g/kg WVR in the diet resulted in lower TTADs of dry matter (P=0.005). Inclusion of 40 g/kg WVR in the diet significantly decreased the nitrogen excretion (P=0.006) and uric acid N excretion (P<0.001). These results suggest that inclusion of 40 g/kg WVR in laying hen diet reduces nitrogen excretion.