Bahram Rahbar, Amir Hossein Asgari Safdar and Nasroallah Moradi Kor
Inadequate dietary energy intake and poor body condition can negatively affect reproductive function. Fats in the diet can influence reproduction positively by altering both ovarian follicle and corpus luteum function via improved energy status and by increasing precursors for the synthesis of reproductive hormones such as steroids and prostaglandins. Supplemental lipids have been used to increase energy density of the diet and may also have direct positive effects on reproduction in animal. Several fatty acid sources have been studied as they relate to reproductive function. Common sources include sunflower, safflower, cottonseed, rice bran, soybeans, fishmeal, animal tallow, and calcium salts of fatty acids. This review will examine dietary fat as a reproductive including the role of fatty acid content and minimum effective intake. Although the consumption of neutral lipids by ruminants is limited under natural conditions, the addition of digestible fats to increase caloric content or to positively modify diet physical characteristics is a long-standing practice. More recently, fat supplements have been used in attempts to influence specific metabolic pathways and, ultimately, hormones that directly modulate ovarian cellular processes. Evidence suggests that the consumption of fat by cattle, particularly polyunsaturated plant oils, can positively influence ovarian follicular growth, luteal function, and postpartum reproductive performance independent of caloric effects. Mechanistically, these effects have been attributed to a cascade of events that change rumen fermentation patterns, heighten lipoprotein-cholesterol synthesis, increase secretion of ovarian steroids, modify circulating concentrations of insulin and GH, and enhance the synthesis or accumulation of IGF-I in ovarian cells. Whole oilseeds, oil milling by-products, and some manufactured products are available to exploit these physiological concepts.
