Differential molecular and hormonal changes in oocytes, granulosa cells and follicular fluid of pregnant and non-pregnant camels.

This study aimed to compare the expression of genes regulating follicles development, survival and steroid hormones secretion in oocytes and granulosa cells (GCs) and study the correlation between their expression and follicular fluid (FF) levels of progesterone (P4) in pregnant and non-pregnant camels. In total, 138 ovarian pairs from slaughtered camels were used. Gene expression and hormonal assay were determined using real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The obtained results revealed that the number of follicles (3-8 mm) was significantly (P < 0.05) lower in pregnant, compared with non-pregnant, camels. P4 level in the FF was significantly (P < 0.05) higher in pregnant, compared with non-pregnant, camels. However, no significant (P > 0.05) difference was noticed in the oestradiol (E2) level. STAR, PTEN, IGF1 and BCL2 mRNA levels were significantly higher in GCs and significantly lower in oocytes of pregnant, compared with non-pregnant, camels. However, follicle-stimulating hormone receptor (FSHR) mRNA level was significantly lower in GCs and oocytes, and the BMP15 mRNA level was significantly lower in oocytes of pregnant, compared with non-pregnant, camels. P4 level in FF was positively correlated with STAR, PTEN, IGF1 and BCL2 mRNA levels in GCs and negatively correlated with BMP15 mRNA levels in oocytes and FSHR mRNA levels in GCs and oocytes of pregnant camels. It could be concluded that pregnancy-induced variations in oocytes and GC expression of BMP15, IGF1, FSHR, STAR, BCL2, and PTEN genes might be associated with a decrease in the number of follicles and an increase in the FF level of P4.

Effect of pretreatment with insulin on the response of buffaloes with inactive ovaries to gonadotrophin-releasing hormone agonist treatment in summer.

The aim of the present study was to evaluate the effect of a pretreatment with insulin on the response of buffalo cows with inactive ovaries to gonadotrophin-releasing hormone agonist (GnRHa) treatment during hot summer months (July and August). Thirty-six Egyptian buffalo cows with inactive ovaries were randomly allocated into three groups: (1) group treated with GnRHa (G1, n = 16) in which each buffalo received an intramuscular injection of 250 mg of GnRHa (Day 0; gonadorelin, Fertagyl); (2) group treated with insulin before the GnRHa injection (G2, n = 8) in which each buffalo received a subcutaneous injection of biphasic insulin at a dose of 0.25 IU kg(-1) bodyweight once daily starting at Day -3 for 3 consecutive days, followed by an intramuscular injection of 250 mg of GnRHa on Day 0; and (3) the control group (G3, n = 12) in which each buffalo cow received an intramuscular injection of 2.5 mL of sterile saline on Day 0. The ovaries of all animals were examined by trans-rectal ultrasonography (5 MHz) on Days -7, -3 and 0 and continued thereafter at 4-day intervals until oestrus or the end of the experiment. On the same days that ultrasound examinations were performed blood samples were collected to measure the progesterone concentrations. Administration of insulin for 3 days before GnRHa injection (G2) significantly (P < 0.05) increased the diameter of the largest follicle from 6.85 +/- 0.64 to 12.4 +/- 0.88 mm. There was a significant (P < 0.01) increase in the oestrous induction rate in G2 compared with both G1 and G3 during the first 12 days after the treatment interval. It is concluded that pretreatment with insulin for 3 days before GnRHa injection increases the diameter of the dominant follicle and therefore the oestrous induction rate of acyclic buffaloes.