Gender Status Effects on Beef Fatty Acid Profile of Angus x Nellore Cattle

Beef fatty acid (FA) profile can be modified by the sex of the animals. Therefore, the goal of this study was to evaluate the influence of gender status on beef FA profile of feedlot Angus x Nellore cattle. A total of 176 cattle, 20 months of age, from the Brazilian Certified Angus Beef Program, were assigned to four sex classes: 32 bulls, 48 steers, 48 immunocastrates, and 48 heifers, presenting initial mean weight of 251.4±3.62 kg for bulls, 266.6±2.95 kg for immunocastrates, 226.4±2.95 kg for steers, and 255.4±2.95 kg for heifers. Cattle were fed during 190 days ad libitum high-grain diet containing 80% concentrate. At the end of the experimental period, cattle were slaughtered. Steaks were collected from the longissimus muscle and stored at -80°C pending analysis for FA profile. Beef FA was extracted and then the methyl esters were formed. FA were quantified using a gas chromatography. Statistical analyzes were performed using the proc MIXED SAS^® program, including the fixed effect of gender status, and the random effect of cattle within gender groups. The gender status had no effect on the total saturated FA (SFA), but significant differences were observed for monounsaturated FA (MUFA), polyunsaturated FA (PUFA), conjugated linoleic acid (CLA), omega 6 (n-6), n-6:n-3 ratio, and PUFA:SFA ratio (P < 0.05). Beef from heifers group had greater levels of MUFA (45.77%; P < 0.01) and CLA (0.42%; P = 0.0006) when compared with bulls (41.56% and 0.30%, respectively), steers (44.21% and 0.30%), and immunocastrates (43.95% and 0.36%). The highest levels of MUFA in the heifers beef was mainly related to the higher levels of the major single FA in this group, namely C18:1 n-9 (35.65%, P < 0.01) and C16:1 n-9 (2.94%, P < 0.01). On the other hand, the levels of PUFA, n-6, PUFA/SFA ratio, and n-6:n-3 ratio were greater (P < 0.01) in the beef from bulls (9.76%, 8.36%, 0.22%, 4.83%, respectively), compared with the other gender status. In conclusion, beef from heifers can be considered healthier to human health, since it presented lower levels of n-6 and myristic acid and higher levels of CLA, MUFA and oleic acid.