Saturated fatty acids can be detrimental to human health and have received considerable attention in recent years. Several studies using taurine breeds showed the existence of genetic variability and thus the possibility of genetic improvement of the fatty acid profile in beef. This study identified the regions of the genome associated with saturated, mono- and polyunsaturated fatty acids, and n-6 to n-3 ratios in the Longissimus thoracis of Nellore finished in feedlot, using the single-step method. The results showed that 115 windows explain more than 1 % of the additive genetic variance for the 22 studied fatty acids. Thirty-one genomic regions that explain more than 1 % of the additive genetic variance were observed for total saturated fatty acids, C12:0, C14:0, C16:0 and C18:0. Nineteen genomic regions, distributed in sixteen different chromosomes accounted for more than 1 % of the additive genetic variance for the monounsaturated fatty acids, such as the sum of monounsaturated fatty acids, C14:1 cis-9, C18:1 trans-11, C18:1 cis-9, and C18:1 trans-9. Forty genomic regions explained more than 1 % of the additive variance for the polyunsaturated fatty acids group, which are related to the total polyunsaturated fatty acids, C20:4 n-6, C18:2 cis-9 cis12 n-6, C18:3 n-3, C18:3 n-6, C22:6 n-3 and C20:3 n-6 cis-8 cis-11 cis-14. Twenty-one genomic regions accounted for more than 1 % of the genetic variance for the group of omega-3, omega-6 and the n-6:n-3 ratio. The identification of such regions and the respective candidate genes, such as ELOVL5, ESSRG, PCYT1A and genes of the ABC group (ABC5, ABC6 and ABC10), should contribute to form a genetic basis of the fatty acid profile of Nellore (Bos indicus) beef, contributing to better selection of the traits associated with improving human health.

Three hundred and ninety Hy-Line W36 commercial laying hens, 46 wk of age, were assigned randomly to 13 dietary treatments for 140 d. Hens were housed in cages (2 hens per cage of 25 × 40 cm) in an open-sided house and were fed diets containing 3% of different fat sources (canola oil, sunflower oil, flaxseed oil, fish oil, and a mixture of 50% flaxseed oil plus 50% fish oil) and 9% ground flaxseed with 2 levels of vitamin E (12 and 100 IU/kg) in a factorial arrangement with 5 replicates of 6 hens each. A control diet, using soybean oil, was also fed. Concentrations of saturated (S), monounsaturated (M), and polyunsaturated fatty acids (PUFA), cholesterol, vitamin E, and sensory analyses of the eggs were measured. The results showed that the lipid profile in the yolk was modified by fat sources. Cholesterol content was slightly reduced by the inclusion of greater quantities of unsaturated fatty acids in the diet. Vitamin E concentration in eggs was related to corresponding dietary levels. There was no influence of the treatments on egg flavor. These findings indicate that is possible to improve the nutritional value of eggs by using flaxseed and increasing the vitamin E content of the diet.