Crude glycerin in diets in feedlot wethers. Centesimal composition and fatty acids profile of longissimus dorsi

The aim was to evaluate the centesimal composition and fatty acids profile of longissimus dorsi of wethers fed diets with increasing levels (0; 2.65; 5.33 e 8.06% in dry matter) of crude glycerin (CG). Were used 20 crossbred, castrated lambs Dorper x St. Ines, with 24 +/- 2.0 kg of weight, housed in individual pens. The experimental design was completely randomized with four treatments and five replications. Diet samples were collected to fatty acids profile analyses. After 84 days of assessment and data collection, the animals were slaughtered. Longissimus dorsi samples were collected and frozen for subsequent analysis of fatty acids by gas chromatography. There was no effect of treatments on the ash content and protein, however, there was influence (P<0.05) on the lipid content and moisture. The fatty acids which had the highest percentages in meat were stearic and oleic acids respectively. These acids were not influenced (P>0.05) by increasing levels of crude glycerin in the diet. There was decreased linear effect (P<0.05) for palmitic fatty acid (16: 0) and quadratic effect (P<0.05) for myristic acid (14: 0) as a function of increasing glycerin levels in diet. The glycerin addition in the diets affected quadratically (P<0.05) the total polyunsaturated fatty acid (PUFA) and omega 6. There was increasing linear effect (P<0.05) for the sum of total conjugated linoleic acid (CLA) and PUFA/SFA ratio. Were not affected by increasing levels of glycerin in the diet the total saturated fatty acids (SFA), monounsaturated fatty acids, omega 3 family and 6 omega/omega 3 ratio. The inclusion of glycerin yielded changes in proximate composition and fatty acid profile of the meat, but these changes did not alter the meat quality.