Sodium monensin or propolis extract in the diet of crossbred (½ Red Angus vs. ½ Nellore) bulls finished in feedlot: chemical composition and fatty acid profile of the Longissimus muscle

Resumo

This work was carried out to evaluate the chemical composition and the fatty acid profile of the Longissimus muscle of crossbred bulls (F1 – ½ Red Angus x ½ Nellore) with an initial average age of 20 months old and an initial average weight of 393 ± 24 kg finished in feedlot. Three treatments (Control – CON, Sodium monensin – MON and Propolis extract – PRO) were evaluated. The animals were kept in feedlot for 70 days and slaughtered at an average weight of 498 ± 25 kg. They were fed with corn silage (roughage), cracked corn, soybean meal, urea, limestone and mineral salt. The roughage:concentrate ratio was 50:50. The bulls were fed twice daily, at 8 a.m. and 4 p.m. The chemical composition and the fatty acid profile of the Longissimus muscle was measured between the 12th and 13th ribs. The inclusion of additives (sodium monensin or propolis extract) did not influence (P > 0.05) the chemical composition (moisture, crude protein, ashes, total lipids and total cholesterol) of the animals’ Longissimus muscle. Therefore, diet has little effect on fatty acid composition of the Longissimus muscle of bulls. However, the percentage of C18:2 n-6 fatty acid was lower (P < 0.05) as a percentage of total fatty acids in the CON diet in comparison to the MON and PRO diets. On the contrary, the percentage of C22:6 n – 3 fatty acid was higher (P < 0.05) as a percentage of total fatty acids in the CON diet in comparison to the PRO diet. However, diet did not influence (P > 0.05) polyunsaturated, monounsaturated, saturated fatty, n-6, or n-3 fatty acids or the ratio of PUFA/SFA and n-6/n-3 fatty acids.