Crude glycerin or glycerol in the lamb diet: A meta-analysis – performance, carcass and meat

Abstract

The intensification of biodiesel production inevitably generates the crude glycerine byproduct, which has little output for other uses mainly due to its purity. The inclusion of crude glycerin (GB) or glycerol (G) as an energy source, mainly as a corn substitute, may be a viable alternative in lamb finishing. In this sense, the objective of this study was to evaluate the levels of GB and G in the diet on lamb performance, carcass characteristics and meat quality through a metanalytic study. Twenty-four high impact articles were selected from research conducted in Brazil and abroad, involving 880 lambs distributed in 86 treatments. Data from both GB and G were grouped into levels. Based on the data contained in these articles were analyzed: initial live weight (PVI), slaughter live weight (PVA), dry matter intake (CMS), average daily gain (GMD), feed conversion (CA), carcass yield (RCQ), cold carcass yield (RCF), loin eye area (AOL), fat thickness (EG), saturated fatty acids (AGS), unsaturated (AGI), monounsaturated (AGMI), polyunsaturated (AGPI) , n6: n3 ratio, crude protein (CP), ether extract (EE), final pH and shear force in relation to control treatment (0% GB or G in MS). The obtained data were submitted to analysis of variance for linear and quadratic effect in each of the variables within all levels and, in the case of significance, regression analysis was performed. The performance, carcass characteristics and meat quality of lambs up to 36.0% of inclusion in the DM of GB and 32.4% of lambs diet did not have deleterious effect on them, and can be considered safe for human consumption. GB and G are presented as an alternative in the diet of finishing lambs, however, the strategy of use as energy substitute should come together with the study of the economic viability based on the price of corn, crude glycerin and demand of finished lambs in the region in question.