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

Abstract

This study investigated the effects of short-term food restriction or supplementation on folliculogenesis and plasma and intrafollicular metabolite and hormone concentrations. Ewes were randomly assigned to three groups: the control group received a maintenance diet (M) while the supplemented group and restricted group received 1.5!M and 0.5!M respectively on days 6-12 of their estrous cycle. Estrus was synchronized by intravaginal progestogen sponges for 12 days. On days 7-12, blood samples were taken. After slaughter, the ovarian follicles were classified and the follicular fluid was collected. Compared with restriction, supplementation shortened the estrous cycle length, decreased the number of follicles 2.5-3.5 mm and follicular fluid estradiol (E 2 ) concentration, increased the number of follicles O3.5 mm and plasma glucose, insulin and glucagon concentrations, and augmented the volume of follicles O2.5 mm. Restricted ewes had higher intrafollicular insulin concentration, but it was similar to that of supplemented ewes. Compared with follicles %2.5 mm, the intrafollicular glucose and E 2 concentrations were increased and the testosterone, insulin, and glucagon concentrations and lactate dehydrogenase (LDH) activity were decreased in follicles O2.5 mm. Only in restricted ewes were intrafollicular LDH and testosterone concentrations in follicles %2.5 mm not different from those in follicles %2.5 mm. In conclusion, the mechanism by which short-term dietary restriction inhibits folliculogenesis may involve responses to intrafollicular increased E 2 , testosterone, and LDH levels in late-stage follicles. This may not be due to the variation of intrafollicular insulin level but rather due to decreased circulating levels of glucose, insulin, and glucagon.

Differences in the metabolomic signatures of porcine follicular fluid collected from environments associated with good and poor oocyte quality

“…Only glucose levels were greater in large follicles compared with small follicles, with the levels of acetate, lactate, hypoxanthine, inositol, trimethylamine and the amino acids alanine, leucine, lysine, methionine and phenylalanine being lower. The finding that glucose concentration increased as follicular diameter increased is consistent with analyses of sheep (Ying et al 2011), cattle (Leroy et al 2004) and buffalo (Nandi et al 2008) FF, but contrary to findings in camels (Ali et al 2008) and horses (Collins et al 1997, Gérard et al 2002. Furthermore, Leroy et al (2004) also observed a concomitant reduction in lactate levels as follicle size increased.…”

Follicle growth, ovulation rate, body weight change, and antioxidant and metabolic status in three fat-tailed sheep breeds fed a half-maintenance diet

“…Thus, the measurement of LDH activity in follicular fluid is important as a potential index of early follicular degeneration. 29 LDH activity was found to reduce in follicular fluid as follicular size increased. 30,44 LDH levels increased in serum of Rahmani and Ossimi ewes, indicating the increase in tissue destruction and explained that large numbers of follicles grow were atretic, so ovulation rate declined in these two breeds; restricted Barki ewes had low LDH, so no change in their ovulation rate was observed.…”

“…Similarly, the concentration of serum insulin was lower in restricted ewes than in those fed ad libitum. 34 Moreover, ewes restricted by 30% for 35 days had low insulin, 35 while Hu ewes fed a 0.5-maintenance diet had slightly lower insulin levels compared to controls, 29 and concentrations of plasma insulin concentrations were lower in low-body condition than in high-body condition ewes during mid-pregnancy. 36 Overall, there were no main effects on insulin concentrations in ewes that were 50% restricted for 27 days, although the insulin levels were lower than in controls.…”

“…27,28 The mechanism by which short-term restriction inhibits folliculogenesis may involve responses to intrafollicular increased estrogen, testosterone, and LDH levels in late-stage follicles, not to variation in intrafollicular insulin level. 29 This effect may be due to decreased circulating levels of glucose. As follicles became larger, the concentrations of glucose and cholesterol significantly increased, while those of triglycerides, lactate, ALP, and LDH significantly decreased.…”

“…21 In Hu sheep fed 0.5-maintenance for 7 days, from day 6 to day 12 of the estrous cycle after removal of the vaginal pessary, lowered glucose levels were recorded from day 7 to day 10, but, on day 12, the glucose level was similar to that of control ewes. 29 …”