Qualidade da carne e expressão de genes envolvidos no metabolismo lipídico de touros Nelore terminados com dietas contendo ou não silagem de espigas de milho (Snaplage)

Abstract

The objective of this study was to evaluate the chemical composition, qualitative characteristics of beef, and genes involved in lipid metabolism in Nellore young bulls fed snaplage. Seventy-two Nellore young bulls with initial body weight of 400 ±27.4 kg were used in a completely randomized design. The experimental diets were control (CON, no snaplage), snaplage + ground corn (SNAP65, with 65% of snaplage) and snaplage (SNA85, with 85% of snaplage). After an experimental period of 86 days, the animals were slaughtered and muscle samples for expression analyses were taken from the Longissimus thoracis (LT) of the left half-carcass at the 13th rib, and twenty-four hours after slaughter, samples were taken to analyze chemical composition, pH, cooking loss, shear force, and color. There was no effect of diet in the intramuscular fat (P > 0.05) of diet. However, animals fed SNAP85 had greater expression of PPARG (P = 0,03). Additionally, the LT of bulls fed SNAP65 and SNAP85 had greater expression of ACACA e SCD1 (P ≤ 0,03) compared to control diet. There were no effects of diet and diet x aging time interaction for pH, cooking loss, shear force, and color (P ≥ 0,11), but the aging time affected all variables. Cooking loss and pH increased with 14 days of aging, whereas shear force decreased with aging time (P ≤ 0,04). In conclusion, the snaplage diet can increase the expression of lipogenic genes and has potential to increase de novo synthesis of intramuscular fat. However, the use of this diet in Zebu cattle does not affect chemical composition, shear force and color.