Nutritional and metabolic parameters in lambs fed diets containing crude glycerine

Abstract

The objective of this work was to evaluate the intake, apparent digestibility, nitrogen balance, ruminal and blood parameters in lambs fed diets containing of crude glycerin. Four castrated lambs of Santa Ines breed with an average weight of 25.0 kg were used. The evaluated diets contained four levels of crude glycerin (0.0, 50.0, 100.0 and 150.0 g kg DM-1). All diets were formulated to meet the nutrient requirements of growing and finishing lambs. The ingredients were: Brachiaria dyctioneura hay as roughage, ground corn grain, soybean meal, urea, mineral salt and crude glycerin. The complete diet provided to the animals was composed of 500 g kg-1 roughage and 500 g kg-1 concentrate on DM basis. A 4 x 4 Latin square experimental design was used. The highest intake (P<0.05) of dry matter (129.08 g kg BW-0.75), neutral detergent fiber (62.91 g kg BW-0.75), acid detergent fiber (41.10 g kg BW-0.75), total carbohydrate (99.92 g kg BW-0.75) and organic matter (116.89 g kg BW-0.75) was achieved with diets varying from 39.2 to 44.7 g kg DM-1 crude glycerin. Crude protein (17.84 g kg BW-0.75) and ether extract (2,70 g kg BW-0.75) intake was higher (P<0.05) with diets containing 39.0 and 77.1 g kg DM-1 of crude glycerin, respectively. Consumed and absorbed N displayed a quadratic effect, whereas retained N displayed a linear decreasing effect in function of crude glycerin levels. Ruminal concentrations of acetate, propionate, and butyrate, and blood glucose was influenced (P<0.05) by the postprandial hour vs. experimental diet interaction. Glycerin levels in the diet did not influence (P>0.05) the apparent digestibility and ruminal N-NH3, pH, ciliate protozoa and blood urea. Therefore, diets containing crude glycerin influenced dry matter intake, with the highest value being around 40 g kg DM-1. Likewise, diets containing crude glycerin influenced the N consumed and absorbed with maximum crude glycerin points of 36.9 and 28.4 g kg DM-1.