Effect of melatonin supplementation in the long-term preservation of the sheep ovaries at different temperatures and subsequent in vitro embryo production

Investigations in the past decades have shown that oocytes developmental competence following in vitro fertilization is greatly influenced by an interval between isolation of the ovaries immediately after death/slaughter and oocytes recovery from the visible follicles. In order to determine the optimal conditions for long-term preservation of ovaries, an experiment was conducted with adding different doses of melatonin (0 (C), 500 (M1), 600 (M2), 700 (M3) and 800 (M4) μM) as an antioxidant to sheep ovaries preservation medium (PBS) maintained at 4 and 20 °C for 24 h. The effects on in vitro embryo production (IVEP) parameters including maturation, fertilization, cleavage, and blastocyst rates and the total number of blastomere were evaluated after the ovaries preservation. Melatonin reduced the decline in fertilization rate as an indicator of success in vitro maturation (P ≤ 0.05). Furthermore, ovarian storage time had significant negative effect (P ≤ 0.05) on IVEP parameters. Supplementation with melatonin increased the total cell number of blastocysts as an indicator of embryo quality (i.e. mean blastomeric cells in 4Math Eq groups: 86.00 ± 3.00, 98.50 ± 3.5, 111.5 ± 1.5, 125.5 ± 2.00 and 126.50 ± 5.5 for C, M1, M2, M3 and M4. respectively). Overall, the results showed that the use of melatonin antioxidant in the ovaries storage medium had beneficial effects on sheep oocytes development and embryos quality

Effect of glucose, lactate and pyruvate concentrations on in vitro growth of goat granulosa cell

Carbohydrates are among the most influential of the numerous components of culture medium that affect metabolism and developmental potential. Glucose, lactate and pyruvate are required for the growth of oocytes and other follicular cells in vitro. The aim of this study was to determine the effects of different concentrations of glucose, lactate and pyruvate on promoting DNA synthesis of granulosa cells in a serum-free medium. Effects of glucose (0.75, 1.5 or 3 mM), pyruvate (0.1 or 0.33 mM) and Llactate (3, 6 or 12 mM) concentrations in the maturation medium on the relative granulosa cell growth during metaphase II (MII) were examined in a 3 × 2 × 3 factorial design. The greatest relative granulosa cell growth response (p<0.05) was observed in the presence of 1.5 mM glucose and 0.33 mM pyruvate or in 6 mM lactate and 0.33 mM pyruvate. Increasing pyruvate concentrations from 0.1 to 0.33 mM resulted in an increase in DNA synthesis in granulosa cells. In conclusion, the results of this study showed that increasing glucose and pyruvate concentrations in the maturation medium increased the growth of goat granulosa cells.Key word: Energy substrate, granulosa cell growth, methyl-3H-thymidine, goat

Effect of oral administration of pioglitazone on follicular dynamics in Holstein dairy cows

This study investigated the effects of oral administration of pioglitazone (PGT), a specific and synthetic ligand of peroxisome proliferator-activated receptors gamma (PPARγ), on follicular dynamics and corpus luteum (CL) functionality in dairy cows. Cows exhibiting strong signs of estrus after 2 injections of PGF2α (given14 d apart) at d 30 postpartum (n = 28) were allotted to four groups (n = 7 cows/treatment) and orally received 6 mg PGT/kg body weight/day according to the following protocol: no PGT (control); PGT for 14 d from 7 d before expected estrus (10 d after 1st injection of PGF2α) to 7 d after observed estrus (PGT14); PGT for 21 d after observed estrus (PGT21); and PGT for 28 d, 7 d before expected estrus to 21 d after observed estrus (PGT28). During the first follicular wave, number of follicles (total and small) increased in PGT14 and PGT28 cows compared to the control group (P < 0.05). During the ovulatory wave, number of total and small follicles increased in PGT28 (P < 0.05) and PGT21 (P < 0.10) compared with PGT14 and control cows. Size of the largest follicle at first wave was greater in PGT28 (P < 0.05), PGT14 (P < 0.05) and PGT21 (P < 0.10) compared to the control cows. Maximal size of the ovulatory follicle was greater in PGT28 (P < 0.05) and PGT21 (P < 0.10) groups compared to the control group. Growth rate of the largest follicle at first wave was higher (P < 0.05) in PGT-treated cows, while growth rate of the ovulatory wave was higher in PGT28 and PGT21 groups, leading to shorter days from luteolysis to ovulation. Pioglitazone administration did not affect CL size, but increased progesterone (P4) concentration. The PGT14 and PGT28 cows had higher maximal plasma P4 concentration and shorter intervals to reach maximal plasma P4 compared to the control group. In conclusion, oral administration of PGT had some positive effects on follicular development and circulating P4 levels which may be conducive to better reproductive performance

Effects of Dietary Beta-Adrenergic Agonist, Terbutaline, on Carcass Characteristics and Blood Attributes in Japanese Quails (Coturnix coturnix japonica)

The effect of dietary Terbutaline, a beta adrenergic agonist, on carcass characteristics and blood attributes in 288 Japanese quails was studied from 21 through 49 days of age. Dietary treatments included four levels of Terbutaline [0 (T0), 1 (T1), 3 (T3), and 5 (T5) mg/Kg of the diet]. Quails were bled at the end of the trial for biochemical assays and the carcass characteristics were then measured. The relative weights of breast and drumstick muscles were increased in birds treated with 3 and 5 mg/Kg diet of Terbutaline (P). Regardless of Terbutaline dietary levels included, the weight of subcutaneous and abdominal fat pad was significantly decreased in treated birds (P). The relative weight of heart was increased in T3 treatment group and that of liver was increased in all birds receiving Terbutaline as compared with the control group (P). Irrespective of the dosing level, the percentage of protein in breast muscle was higher in Terbutaline-treated birds (P). However, the fat percentage in drumstick muscle was reduced in birds treated with 3 and 5 mg/Kg diet of Terbutaline, but its protein percentage was increased in T1, T3, and T5 (P). A significant increase in plasma levels of free fatty acids was found in all birds that received Terbutaline (P) as compared with the control. Overally, the data suggested that dietary Terbutaline had a profound positive effect on carcass composition, but a minimal one on the plasma metabolites (glucose, cholesterol, and triglyceride) of Japanese quails

Effects of equine chorionic gonadotropin (eCG) administration and flushing on reproductive performance in Nadooshan goats of Iran

An experiment was conducted on Nadooshan goats of Iran, during the breeding season, to evaluate the effectiveness of flushing and equine chorionic gonadotropin (eCG) treatment on reproductive traits. Ninety-two intact does with an average live weight of 25.11 ± 3.933 kg were randomly divided into four equal experimental groups. Controlled internal drug release device (CIDR) were inserted for 18 days in all groups. Experimental groups consist of: 1-Control (C); 2-eCG (600 IU; E); 3-eCG (600 IU) + Flushing (E+F); and 4-Flushing (F). Does in two last groups (E and E+F) were injected intramuscularly, at the time of CIDR withdrawal, with 600 IU of eCG. The first group (C) received no treatment and served as a control. All animals were submitted to pasture and mineral licks and groups E+F and F additionally received flushing ration. Pregnancy rate in group F was more than the control group (p &lt; 0.05). Twinning rates and kid crops in groups E+F and F were significantly higher than control group (p &lt; 0.05). Time of onset of estrus decreased in groups with eCG administration (E and E+F). Therefore, it is concluded that the flushing especially coupled with the eCG treatment can improve reproductive performance in Nadooshan goats treated with CIDR during the breeding season

Alterations in reproductive hormones during heatstress in dairy cattle

In dairy cows inseminated during the hot months of the year, there is a decrease in fertility. Different factors contribute to this situation; the most important are a consequence of increased temperature and humidity that result in a decreased expression of overt estrus and a reduction in appetite and dry matter intake. Heat stress reduces the degree of dominance of the selected follicle and this can be seen as reduced steroidogenic capacity of its theca and granulosa cells and a fall in blood estradiol concentrations. Plasma progesterone levels can be increased or decreased depending on whether the heat stress is acute or chronic, and on the metabolic state of the animal. These endocrine changes reduce follicular activity and alter the ovulatory mechanism, leading to a decrease in oocyte and embryo quality. The uterine environment is also modified, reducing the likelihood of embryo implantation. Systems activated by heat stress can influence reproduction at the hypothalamus, pituitary gland or gonads. However, the major impact is thought to be within the brain or at the pituitary gland. Measurement of plasma concentrations of the gonadotrophins provides a good indication of the effects at these higher levels, since the pulsatile secretion of luteinizing hormone (LH) is a reflection of the secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. Both the secretion and actions of GnRH are influenced by the feedback actions of gonadal sex steroids and inhibin. Recent studies suggest that the use of gonadotropins to induce follicular development and ovulation can decrease the severity of seasonal postpartum infertility in dairy cows