Uso do grão de soja processado na alimentação de bovinos confinados

Abstract

In this study aimed to evaluate the performance, fatty acid profile and gene expression of transcription factors involved in lipid metabolism in beef of crossbred young bulls fed with milled or extruded soybeans. Sixty crossbred young bulls were used, with average initial age 20 months and average alive initial weight 320 ± 8.12 kg, distributed in a completely randomized design. Three types of diets were provided, representing the following treatments: without additional lipid, milled and extruded soybean. The diets contained, respectively, 2.4, 6.1 and 6.3% ether extract. There was no effect of diet on animal performance, carcass characteristics, color and pH of the longissimus dorsi muscle (P>0.05). Diets with soybean, regardless of processing, had lower lauric acid content (C12:0) and CLA (C18: 2 c9, t11); and higher stearic acid content (C18:0). The myristic acid content was higher in animals fed diet without additional lipid compared to the animals receiving milled soybean, as the animals that were fed with extruded soybean did not differ statistically from the other treatments. There was a trend (P = 0.07) in decreasing the palmitoleic acid content (C16:1 c9) in animals receiving milled soybean. It is verified that the transoctadecenoic acids content (C18:1 t9, 10, 11) and EPA (C20:5 n3) were greater in the muscle of animals that received the diet with milled soybean compared to extruded soybean and without additional lipid. On the other hand, oleic acid content (C18:1 c9) in the muscle of animals receiving milled soybean was lower. The gene expression of the transcription factor per peroxisome proliferator activated receptor (PPARs) was not influenced by diet (P<0.05), as the transcription factor of steroid binding proteins (SREBF1) was more expressed (P>0.05) in the muscle of animals that received soybean. The luminosity index and intensity of red increased with maturation (P<0.05). The use of processed soybeans does not alter the performance, carcass characteristics, chemical composition, pH, and muscle color; and was unable to raise the unsaturated fatty acids content and CLA c9, t11 in relation to a diet without using soybean. However, the diet with extruded soybean resulted in increased expression of the gene SREBF1, which influenced the meat fatty acid profile.