Effect of functional oils and high levels of glycerine in the diet of Purunã bulls finished in a feedlot on fatty acid composition in the Longissimus muscle grilled

Abstract Text: Bulls were distributed in a complete randomized design by a factorial scheme 2 x 2 to evaluate the effects of the addition of a commercial mixture of functional oils – cashew and castor oil (Essential^®, Oligo Basics, Paraná, Brazil) and the effects of corn replace by glycerine (800 g of glycerol kg^-1) in the diet of Purunã bulls on fatty acids of the Longissimus muscle grilled. Thirty-three bulls (206.1 ± 20.0 kg BW, 8 months old) were allocated in individual pens and distributed into 4 treatments: CON - without glycerine or functional oils), FOL - functional oil (3 g animal^-1 day^-1), GLY – 203 g kg^-1 of glycerine of dry matter and GFO – 203 g kg^-1 of glycerine of dry matter and 3 g animal^-1 day^-1 of functional oils. The bulls were fed during 252 d a diet with 420 g corn silage, 477 g ground corn, and 103 g soybean meal day^-1; or a diet with 420 g corn silage, 203 g glycerol and 150 g soybean meal. All diets were kept isonitrogenous and isoenergetic. The bulls were slaughtered at commercial slaughterhouse with BW of 468 kg (SD 31.53) ± 19 months old. The carcasses were labelled and chilled for 24 h at 4^oC. Longissimus muscle samples were taken by complete cross-section between the 12^th and 13^th ribs and taken to the laboratory and was frozen at -20^oC. Longissimus muscle samples were sliced into 1 cm-thick steaks 2 h before grilling. Industrial grill was used to samples grilling at 200 °C until reaching 75 °C internal temperature. Total lipids were extracted using method with a chloroform/methanol mixture. Fatty acid methyl esters (FAME) were prepared by triacylglycerol methylation according ISO-R-5509 (1978). Then, the esters were extracted with 2 mL of n-heptane and stored at -18 °C for later chromatographic analysis (Thermo 3300 gas chromatograph). Retention times and peak area percentages were automatically computed with Chronquest 5.0 software. The fatty acids composition in the Longissimus muscle grilled were similar (P>0.05) for bulls fed with functional oils addition. On the other hand in the diet with high level of glycerine the fatty acids (P<0.05) pentadecanoic, margaric, cis-10-heptadecaenoic, oleic, cis-vaccenic, and ∑-monounsaturated increase in the Longissimus muscle grilled. Whereas the fatty acids 15:1 n-9, stearic, docosapentaenoic, ∑-saturated fatty acid and ratio ∑-Omega-6:∑-Omega-3 had reduction in the Longissimusmuscle grilled of bulls feed with glycerine.

Keywords: cashew nutshell liquid; castor oil; meat quality