Flax meal supplementation on the activity of antioxidant enzymes and the expression of oxidative stress- and lipogenic-related genes in dairy cows infused with sunflower oil in the abomasum

The effects of abomasal infusion of sunflower oil (SO) and flax meal (FM) supplementation on activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in blood and mammary tissue and mRNA abundance of oxidative stress- and lipogenic-related genes in mammary tissue of dairy cows were examined. Eight lactating Holstein cows were assigned to a double 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: (1) no FM in the diet (CON); (2) diet containing 13.7 g/kg FM; (3) no FM in the diet and 250 g SO/d infused in the abomasum; and (4) diet containing 13.7 g/kg FM and 250 g SO/d infused in the abomasum. mRNA abundance of Kappa-B1 in mammary tissue tended to decrease with FM supplementation, while mRNA abundance of SOD2 tended to increase when SO was infused in the absence of FM in the diet. Fatty acid synthase, lipoprotein lipase and stearoyl-coA desaturase gene expression tended to decrease with SO infusion when cows were fed CON. Infusion of SO decreased mRNA abundance of peroxisome proliferator-activated receptorγ1 in mammary tissue of cows fed CON and sterol regulatory element binding transcription factor 1 expression decreased with SO infusion. In conclusion, FM had no effect on oxidative stress-related gene expression in mammary tissue of cows that were infused with SO in the abomasum. Limited effects were observed on mRNA abundance of antioxidant-related genes in mammary tissue whereas abomasal infusion of SO reduced lipogenic-related gene expression.