1806
Supplementation of selenium plus vitamin E vs. canola oil in the diet of feedlot cattle: which one can improve nutritional quality of meat modifying gene expression?
The metabolic conversion of dietary components is a control mechanism for gene expression, so the present study aimed to evaluate the effects of selenium (Se), vitamin E and canola oil on the expression of antioxidant and lipogenic genes. Forty-eight Nellore bulls at calan gate allocated in the Department of Animal Science USP-FZEA-Brazil were divided into four groups: Control(C): basal diet (30% forage- corn silage- and 70% concentrate, dry matter according to the nutrient requirements recommended by NRC,1996); Se+Vit E: addition of 2.5mg Se+500 IU vitamin E; Canola: addition of 3% canola oil; Se+Vit E+Canola: addition of 3% canola oil+2.5mg Se+500 IU of vitamin E(/kg DM, always). After 12 weeks, the animals were slaughtered at the Abattoir-School Campus and liver samples collected. Total RNA was extracted using RNeasy Tissue Kit (Qiagen®), measured at 260 and 280nm, analyzed by agarose gel. RNA was converted into cDNA using DNase I and High Capacity RNA-to-cDNA kit and it was used for determination of gene expression by RT-qPCR using Taqman probes, 18S as endogenous control (Applied Biosystems®) and calculated by Pfaffl’s equation. The data were analyzed by Mixed SAS 2009 and contrasts used were: control vs. other (C1); Se+Vit E and Canola vs. Se+Vit E+Canola (C2); Se+Vit E vs. Canola (C3). The results are in Table 1. The supplementation with Se+Vit E and Canola didn’t show effects when compared to the control (C1), but differences were observed between Se+Vit E and Canola (C3), which had opposite effects. Se+Vit E induced expression of cytoprotectives genes (NRF2, GPXs, GSS) and increased the expression of responsible gene for the synthesis of CLAs (SCD) encouraging studies to improve nutritional quality of meat, but caution is needed because it can induce the synthesis of cholesterol through the expression of the gene HMG-CoA-R. Although Canola didn’t increase the expression SCD gene, canola oil reduced the expression of HMG-CoA-R gene.
Table 1. Gene expression.
GENE |
C |
Se+Vit E |
Canola |
Se+Vit E+Canola |
Pr > F |
C1 |
C2 |
C3 |
NRF2 |
1.1661 |
1.8295 |
0.8032 |
1.121 |
0.0525 |
0.7904 |
0.5756 |
0.0079 |
GPX-1 |
1.1209 |
1.6099 |
0.8125 |
1.1594 |
0.08 |
0.783 |
0.8467 |
0.0109 |
GPX-4 |
1.3153 |
2.6565 |
1.1741 |
1.0114 |
0.0265 |
0.553 |
0.1032 |
0.0118 |
SCD |
1.4732 |
2.3247 |
1.0792 |
2.674 |
0.0568 |
0.289 |
0.0751 |
0.0572 |
HMG-CoA-R |
1.1911 |
1.4905 |
0.2459 |
0.9522 |
0.0633 |
0.4948 |
0.811 |
0.0096 |
Keywords: antioxidants, bovine, cholesterol.