Changes in the expression pattern of genes affecting the growth and development of mammary tissue in pregnant Saanen goats in response to dietary fats.

The period from mid-pregnancy to term is a pivotal phase for the growth and development of the mammary glands. Diets containing unsaturated fat may also influence this process. This study examined the effects of saturated and unsaturated fat supplements on mammary gland growth in Saanen goats. Forty goats were divided into four groups: C- (negative control, no added fat), C+ (positive control, saturated palm oil), SB (Omega-6, roasted soybean), and FS (Omega-3, extruded flaxseed). Blood parameters, histological data, and the expression of genes related to mammary tissue growth and apoptosis were examined. Our findings showed that the C- group had the highest (p ≤ 0.05) serum insulin and lowest (p ≤ 0.05) serum triglyceride concentrations compared with the other groups. Serum cortisol concentration was lower (p ≤ 0.05) in the C+ group than in the C- and SB groups. Blood glucose concentration was lower (p ≤ 0.05) in the FS group compared to the C- and C+ groups. The total serum cholesterol concentration was lower (p ≤ 0.05) in the C- group than in the C+ and SB groups. The percentage of epithelial cells was higher (p ≤ 0.05) in the FS group, while the percentage of stroma was higher in the C+ group. Additionally, the SB group's alveolar, epithelial, and luminal areas were higher (p ≤ 0.05) than those in the other groups. The expression of the Insulin-like growth factor binding protein-5 (IGFBP-5) was the highest for the FS group (p ≤ 0.05). However, the expression of Insulin-like growth factor-I, Insulin-like growth factor binding protein-3 (IGFBP-3), Bcl-2 associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), Tumor necrosis factor-α (TNF-α), and the Bax/Bcl-2 ratio did not differ between the groups. In conclusion, providing goats with flaxseed during mid-pregnancy can promote mammary epithelial cell growth and development, prolong the lifespan, delay apoptosis, and sustain milk production.