Effect of diets containing different levels of crude glycerol on nutrient intake in lambs

Abstract Text:

Crude glycerin is a byproduct of biodiesel production that represents a potential ingredient for use in animal nutrition. The objective of this study was to evaluate the effect of diets containing different levels of crude glycerin on nutrient intake in male lambs. The experiment was conducted in the animal metabolism laboratory of Universidade Estadual de Londrina. Four castrated male lambs (25 ± 2.6 kg) were used in a 4 × 4 Latin square design. Animals were identified and individually allocated to metabolic cages containing a feeder and a water trough. The experiment was divided in 4 periods of 13 d, with the first 7 d for diet adaptation and 6 d of sample collection. A basal diet (50:50 forage to concentrade) consisting of chopped Brachiaria dyctioneura hay, ground corn, soybean meal, urea and a mineral and vitamin premix was provided throughout the experiment. Crude glycerin was added to the basal diet at either 0, 5, 10 or 15% of diet DM. Diets were made isocaloric and isonitrogenous by the addition of ground corn and urea, respectively. Daily intake was measured based on individual orts. Samples of offered diets and orts were analyzed for DM, OM, CP, NDF, ADF, ether extract (EE) and total carbohydrates (TC). Data was submitted to analysis of variance and regression with 5% significance level. The inclusion of crude glycerin influenced the intake of nutrients (P<0.01) when expressed as g/d, %BW and g/kg^0.75, with a quadratic response for all parameters evaluated. Overall, the highest theoretical nutrient intake in kg/d was between 3.81 and 5.14% glycerol inclusion. Only CP and EE, when expressed as %BW and g/d, resulted in higher theoretical intake for diets containing glycerin at 10.88 and 7.91% inclusion, respectively. Nutrient intake for all treatments was sufficient to meet the nutritional requirements, and to keep the body condition score, within the desired to maintain the physiological status of the animals during the experimental period. Crude glycerin, when fed to lambs in a 50:50 forage to concentrate diet, can be included up to 5.14% of diet DM without negatively affect the intake of nutrients in g/d and g/ kg^0.75. 

Keywords: byproduct, small ruminants, energy