PSIII-A-13 Intramuscular fat and expression of genes involved in lipid metabolism and gluconeogenesis in nellore bulls fed snaplage

Abstract

We hypothesized that diets with snaplage would increase the expression of lipogenic genes, resulting in higher marbling fat content, compared to a diet of whole-plant silage and reconstituted corn silage. Therefore, the objective of this study was to analyze the chemical composition, as well as the expression of genes involved in lipid metabolism and liver gluconeogenesis of Nellore bulls fed snaplage. Seventy-two Nellore bulls (24 months, initial body weight 400 ±27.4 kg) were used in a completely randomized design. Animals were stratified by body weight, housed in 24 pens (3 animals per pen), and designed to one of the three treatments (8 pens per treatment). Experimental diets (around 14% of crude protein) were: control (corn silage, ground and reconstituted corn grain, protein sources), snaplage + ground corn, replacing completely corn silage (SNAP65, with 65% snaplage), and snaplage 85, replacing completely corn silage and corn grain (SNAP85, with 85% snaplage). Data were analyzed using MIXED procedure of SAS 9.4 with fixed effects of dietary treatment, and random effects of pen nested within treatment. Overall, diets did not affect (P>0.11) the intramuscular fat. However, animals fed SNAP85 showed higher PPARG expression (P=0.03). The muscle of animals fed snaplage (SNAP65 and SNAP85) also had higher expression of ACACA and SCD1 genes (P≤0.03) than the control animals. The FABP4 expression tended to be higher (P=0.10) in the muscle of animals fed SNAP85 compared with SNAP65. In addition, animals fed control diet tended to have higher (P=0.07) expression of PC in the liver compared with animals fed SNAP65 and SNAP85. Also, PEPCK2 expression was lower (P=0.05) in in the liver of animals fed SNAP65 diet than control SNAP85. We conclude that diets with snaplage increased the expression of genes involved in the muscle lipogenesis, without increase intramuscular fat.