A mixture of the branched chain amino acids leucine, isoleucine and valine increases ovulation rate in ewes when infused during the late luteal phase of the oestrous cycle: an effect that may be mediated by insulin

Abstract

The positive relationship between nutritional state and ovulation rate in sheep may involve the action of specific nutrients on gonadotrophin release. LH and FSH secretion is controlled in part by hypothalamic GnRH, which is in turn influenced by central adrenergic and serotonergic neuronal systems. In this experiment the branched chain amino acids (BCAAs) leucine, isoleucine and valine were examined for effects on LH and FSH secretion. A mixture of the three amino acids was infused into ewes for 5 days immediately before luteolysis, a time when nutritional effects on ovulation rate occur. The infusion significantly increased ovulation rate without any associated increase in FSH or LH. However, the infusion did increase plasma insulin concentrations and this effect, together with the high levels of blood urea observed, suggests that these amino acids had increased the supply of energy substrates to the follicles. An increase in insulin-mediated glucose uptake by follicles could be the stimulus responsible for the increase in ovulation rate. The ability of the animal to utilize BCAAs for energy metabolism may be an important component of the ovulation responses to nutrition.

Productive and Reproductive Traits of Sheep Fed Acacia saligna Leaves-Based Diets

“…These effects probably occur as a result of including tannins-rich plants in ewe's diets, which enhance the live body weight, body condition, and energy and protein intake and protein absorption from the small intestine [29]. Moreover, increased plasma of essential amino acids principally branched chain amino acids and plasma metabolic hormones especially insulin were found in tannin-fed animals [30]. Short periods of improved nutrient supply before and during mating and reproduction have been known to affect ovulation rate along with increased size and number of follicle [31], reduce follicular atresia [32], altered plasma gonadotrophin concentration [33] and affect ovarian sensitivity to gonadotrophins [32].…”

Changes in barrier health status of the gill for grass carp (Ctenopharyngodon idella) during valine deficiency: Regulation of tight junction protein transcript, antioxidant status and apoptosis-related gene expression

“…The up-regulation of mTOR expression increased Nrf2 expression in human hepatic cells. Valine decreases insulin levels in sheep plasma [33]. Seiliez et al [34] reported that insulin may be involved in the beneficial effects on TOR expression in rainbow trout muscle cells.…”

Effect of different levels of short-term feed intake on folliculogenesis and follicular fluid and plasma concentrations of lactate dehydrogenase, glucose, and hormones in Hu sheep during the luteal phase

“…Many studies reported that short-term nutritional supplementation stimulated follicle development or ovulation rate (Teleni et al 1989, Downing & Scaramuzzi 1991, Downing et al 1995a, 1995c, van Barneveld 1999, Munoz-Gutierrez et al 2002, Viñoles et al 2005, Somchit et al 2007. The current theory regarding the immediate effect of nutrition on folliculogenesis is that metabolites and metabolic hormones act as signals directly on follicles to regulate folliculogenesis (Scaramuzzi et al 1993, Downing et al 1995a, 1995b, 1995c, Scaramuzzi et al 2006, since glucose transporter proteins and specific receptors are present in the follicles (Williams et al 2001, Munoz-Gutierrez et al 2004, Sutton-McDowall et al 2010; however, there was little information about follicular fluid responses to the short-term nutritional treatment.…”

“…Short-term nutritional treatment increased the plasma concentrations of glucose and insulin (Teleni et al 1989, Downing & Scaramuzzi 1991, Downing et al 1995a, 1995b, 1995c, van Barneveld 1999, Viñ oles et al 2005, Alexander et al 2007, elevated intrafollicular glucose concentration, and lowered progesterone concentration in small follicles, but it did not affected estradiol (E 2 ) secretion (Somchit et al 2007). Glucose consumed by follicles can be used for energy production, cellular homeostasis, nuclear maturation, and as substrates for matrix production to maintain follicle development (Sutton-McDowall et al 2010).…”