Plasma inhibin levels in relation to steroids and gonadotrophins during oestrous cycle in buffalo.

The study was conducted on six Murrah buffalo synchronized and induced to oestrus. An indwelling catheter was placed in the jugular vein of each buffalo 4 days before the expected onset of the oestrus following the induced oestrus and blood samples were collected at 8 h intervals from each animal throughout the oestrous cycle. Plasma immunoreactive inhibin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol-17 beta and progesterone were estimated by radioimmunoassay to study the variations in the peripheral levels of these hormones and their inter-relationships in order to elucidate the feedback systems controlling them during the oestrous cycle of buffalo. Plasma inhibin levels ranged between 391.25 and 631.97 pg/ml during various phases of the oestrous cycle and were found to be higher than reported in cows. Peak LH and FSH levels during oestrus were 38.40 +/- 9.21 and 24.04 +/- 4.75 ng/ml, respectively and estradiol-17 beta and progesterone were 19.50 +/- 5.51 pg/ml and 0.61 +/- 0.25 ng/ml, respectively. The mean plasma inhibin concentration on the day of oestrus was 562.5 +/- 18.9 pg/ml. Levels of FSH in the plasma showed three mid-cycle elevations which corresponded to comparatively lower inhibin and elevated estradiol-17 beta levels during the same period. From this observation it was deduced that both inhibin and estradiol-17 beta have a feed-back regulatory effect on FSH secretion in buffalo.

Circadian and pulsatile variations in plasma levels of inhibin, FSH, LH and testosterone in adult Murrah buffalo bulls.

The present study investigated pulsatile and circadian variations in the circulatory levels of inhibin, gonadotrophins and testosterone. Six adult buffalo bulls (6 to 7 yr of age) were fitted with indwelling jugular vein catheters, and blood samples were collected at 2-h intervals for a period of 24 h and then at 15-min interval for 5 h. Plasma concentrations of inhibin, FSH, LH and testosterone were determined by specific radioimmunoassays. Plasma inhibin levels in Murrah buffalo bulls ranged between 0.201 to 0.429 ng/mL, with a mean of 0.278 +/- 0.023 ng/mL. No inhibin pulses could be detected during the 15-min sampling interval. Plasma FSH levels ranged between 0.95 to 3.61 ng/mL, the mean concentration of FSH over 24 h was 1.66 +/- 0.25 ng/mL. A single FSH pulse was detected in 2 of 6 bulls. The LH levels in peripheral circulation ranged between 0.92 to 9.91 ng/mL, with a mean concentration of 3.33 +/- 1.02 ng/mL. Pulsatility was detected in LH secretion with an average of 0.6 pulses/h. Plasma testosterone levels in 4 buffalo bulls ranged from 0.19 to 2.99 ng/mL, the mean level over 24 h were 1.34 +/- 0.52 ng/mL. Testosterone levels in peripheral circulation followed the LH secretory pattern, with an average of 0.32 pulses/h. The results indicate parallelism in inhibin, FSH and LH, and testosterone secretory pattern. Divergence in LH and FSH secretory patterns in adult buffalo bulls might be due to the presence of appreciable amounts of peripheral inhibin.

Comparison of quality and freezability of water buffalo semen after washing or Sephadex filtration.

Split aliquots of pooled buffalo semen samples were processed before freezing 1) by washing twice with Tris-citric acid buffer by centrifugation and re-suspension to the original volume in the same buffer, or 2) or by passage through a G-15 Sephadex column. The effect of these procedures on progressive motility, percentages of live spermatozoa, sperm abnormalities and intact acrosomes and release of glutamate oxatoacetate transaminase (GOT) into the medium were assessed after extension, after equilibration and after 18 to 24 h or 15 d of frozen storage. Prior to extension, gel filtration reduced sperm concentration and enhanced progressive motility, whereas washing produced little effect on these attributes. Except in the case of GOT release, which was significantly (P < 0.05) lower after the washing of semen (34.3 +/- 16.40) than the filtering of semen (45.7 +/- 12.35), the 2 procedures did not cause significant effects (P > 0.05). Damage to spermatozoa due to freeze-processing was also similar in the 2 treatments, and the extent of beneficial effect in improved motility and live spermatozoan numbers after thawing was also similar.

Lipid peroxidation in buffalo (Bubalus bubalis L.) spermatozoa: effect of added vitamin C and glucose.

Addition of 2.5 mM vitamin C or 40 mM of glucose to washed buffalo spermatozoan suspensions in Ca2(+)-free Kreb's Ringer Hanseliet saline buffer (pH 7.0) resulted in significant lower malonaldehyde concentration and higher spermatozoan motility and liver spermatozoa compared to control levels after 45 min of aerobic incubation at 37 degrees C or pre-incubation levels.

Effect of dietary zinc and copper on peripheral blood plasma cholesterol, testosterone and histomorphology of testes in rats.

Total plasma cholesterol (mg/dl) significantly (P less than 0.01) decreased from 70.8 to 54.01 as the dietary Cu levels increased from 2.5 to 5 ppm at 12 pm Zn concentrations in male weanling rats. A similar trend was observed in the blood peripheral testosterone concentration at 12 ppm Zn and 2.5 ppm Cu. Histological examination of testes revealed smaller seminiferous tubules with atrophy of germinal epithelium. Also a marked loss of spermatogenic cells was observed in Zn and Cu deficient rats.

Effect of vitamin E on lipid peroxidation in buffalo Bubalus bubalis L.

Vitamin E significantly (P less than 0.01), inhibited lipid peroxidation as indicated by malonaldehyde (MDA) production and improved significantly (P less than 0.01) motility and percent live spermatazoa of B. bubalis semen. Bulls with higher MDA formation had lower sperm motility and percent live count. Variance due to bulls for all the three parameters were significant (P less than 0.05).