Effect of Roasted Soybean and Canola Seeds on Peroxisome Proliferator-Activated Receptors Gamma (PPARG) Gene Expression and Cattle Milk Characteristics

The aim of this research was to investigate the changes in milk yield and its composition, fatty acid profile and peroxisome proliferator-activated receptors gamma (PPARG) gene expression in adipose tissue of Iranian Holstein cattle in response to feeding isonitrogenous and isocaloric diets but formulated based on different oilseeds (soybean or canola seeds). Twenty cows were tested randomly with experimental diets. Sampling from subcutaneous adipose tissue was performed. Moreover, fatty acid composition was analyzed, total RNA was isolated, cDNA synthesized and samples were amplified. SPSS 16.0, LinRegPCR and REST software were used to analyze real-time polymerase chain reaction results of gene expression. The amount of PPARG gene expression in the adipose tissue for canola seed treatment, in comparison with the soybean seed was higher. The milk production, 4% fat corrected milk, fat percentage, milk urea nitrogen and body condition score between two treatments was significant (P<0.05). The results showed that the amount of some fatty acids extracted from adipose tissue was changed by altering the diet. As, for C16:1, C18:0 and C18:3t fatty acids, there was a significant effect between the two treatments (P<0.05). In general, the PPARG gene expression was not significant in canola that can be due to the similarity of most of the fatty acids between canola and soybean, and the similarity and nutrient balance of the diet. Therefore, canola seed can be a good option for dairy cattle diet due to high levels of fat and protein and lower prices than soybean seed. It can also be used to improve milk, with the effect of feeding on the fatty acid composition of the milk.