Influence of the gross dietary level of glycerin on performance, blood parameters, carcass yield, and quality of meat of broilers

The objective of this study was to evaluate the effects of crude glycerin (CG) levels on performance, blood parameters, carcass yield and cuts, carcass chemical composition, and meat quality in broiler chickens. A total of 1,056 birds were randomly distributed into 2 experimental phases. In phase 1 (1–21 D), 6 levels of CG (0, 1, 3, 5, 7, and 9%) were supplemented in the diets, CG was supplemented at the expense of corn. Each CG level consisted of 8 replicates of 22 birds. In phase 2 (22–42 D), the inclusion levels of CG were maintained; however, 4 replicates of each CG level were given a CG-free ration. For this phase, each treatment combination consisted of 4 replicates. The inclusion of 5, 7, and 9% CG provided better weight gain (P < 0.05) than the control treatment (0% CG) during phase 1. The birds that received CG for both phase 1 and 2 (1–42 D) presented body weight gain, lower feed intake, and better feed conversion ratio relative to the group that received CG for only phase 1 (P < 0.05). Birds that received CG in their diet until age 21 D had higher blood levels of cholesterol and alanine aminotransferase than birds that received CG up to 42 D. The level of CG also influenced the protein deposition and the water retention of the carcass. It is concluded that CG can be included in broiler diets up to 9%, without impairing performance, blood parameters, and qualitative attributes of the meat.