The objective was to evaluate the effects of corn replacement by crude glycerin (CG) in diets with high-concentrate diets and low starch on enzyme activities and atherogenicity index of lamb meat. Forty Santa Ines lambs (23.5 ± 1.35 kg BW) were assigned to a randomized block design with 5 treatments: 0, 7.5, 15, 22.5, and 30% of CG on dry matter basis. The diet with 30% of CG promoted total replacement of corn. Diets consisted of Tifton-85 hay, corn, crude glycerin (83% glycerol), corn gluten meal, corn oil, urea, sunflower meal, soybean hulls and mineral. All diets had around 18% roughage and 82% concentrate. The Animals were housed in individual pens and fed ad libitum twice daily at 0700 and 1600 h. The experimental period had 72 ± 7 d of duration and the animals were slaughtered when reached 38 kg BW. The indices of enzyme activities Δ⁹-desaturase on C16 and C18 fatty acids and enlogase, as well as atherogenicity index (indicator of the risk of cardiovascular disease) were calculated using the concentration of fatty acids from Longissimus muscle. Orthogonal contrasts were used to determine the linear and quadratic effects of CG and also contrast of 0% CG vs. CG treatments were used. The enzymatic activity indexes for elongase and Δ⁹ desaturase 16 and 18 increased linearly with increasing dietary crude glycerin (P ≤ 0.02). Activity indexes were also higher in the meat from animals fed CG, regardless of concentration, when compared with meat from animals fed without CG (P ≤ 0.04). Increasing CG linearly reduced the meat atherogenicity index (P < 0.01). Moreover, the index was lower in animals fed CG, regardless of concentration, in comparison to animals fed CG (P < 0.01). The CG can provide higher activity of enzyme linked to production of CLA and oleic fatty acid in lamb meat. The CG has potential to decrease the risk of cardiovascular disease.