Sarvpreet Singh Ghuman

Integration between different hypothalamic nuclei involved in stress and GnRH secretion in the ewe.

This study investigated possible integrated links in the neuroanatomical pathways through which the activity of neurones in the paraventricular nucleus and arcuate nucleus may modulate suppression of gonadotrophin-releasing hormone (GnRH) secretion during stressful situations. Double-label immunofluorescence and laser scanning confocal microscopy were used to examine the hypothalamic sections from the follicular phase ewes. Noradrenergic terminals were in close contact with 65.7 ± 6.1% corticotrophin-releasing hormone (CRH) and 84.6 ± 3.2% arginine vasopressin (AVP) cell bodies in the paraventricular nucleus but not with β-endorphin cell bodies in the arcuate nucleus. Furthermore, γ-amino butyric acid (GABA) terminals were close to 80.9 ± 3.5% CRH but no AVP cell bodies in the paraventricular nucleus, as well as 60.8 ± 4.1%β-endorphin cell bodies in the arcuate nucleus. Although CRH, AVP and β-endorphin cell terminals were identified in the medial pre-optic area, no direct contacts with GnRH cell bodies were observed. Within the median eminence, abundant CRH but not AVP terminals were close to GnRH cell terminals in the external zone; whereas, β-endorphin cells and terminals were in the internal zone. In conclusion, neuroanatomical evidence is provided for the ewe supporting the hypothesis that brainstem noradrenergic and hypothalamic GABA neurones are important in modulating the activity of CRH and AVP neurones in the paraventricular nucleus, as well as β-endorphin neurones in the arcuate nucleus. These paraventricular and arcuate neurones may also involve interneurones to influence GnRH cell bodies in medial pre-optic area, whereas the median eminence may provide a major site for direct modulation of GnRH release by CRH terminals.

In utero exposure of neonatal buffalo calves to pesticide residues and the alterations within their reproductive tract.

In utero exposure of neonates to pesticide residues could be damaging to the reproductive tract. Hence, the present study assessed the circulating concentrations of pesticide residues in buffalo and their neonatal calves as well as in the reproductive tract tissue samples of same calves. Also, histopathological alterations were revealed in the reproductive tract of calves. Pesticide residues were high (P<0.05) in the reproductive tract of calves (119.5 ± 20.2 ng/g, 35% positive) in comparison to their blood (32.1 ± 8.4 ng/ml, 15% positive) or blood of their dams (41.5 ± 8.3 ng/ml, 25% positive). The number of histopathological alterations were high (P<0.05) in the reproductive tract of a calf contaminated with high concentrations of pesticide residues (3.43 ± 1.29) in comparison to a tract positive for low residue concentrations (1.57 ± 0.60) or pesticide negative tract (0.28 ± 0.10). In conclusion, in utero exposure of neonatal buffalo calves to pesticide residues may be associated with damaging alterations in their reproductive tract.

Size of dominant follicle, plasma progesterone and estradiol levels on the day of ovulation and subsequent conception rate in buffalo (Bubalus bubalis) following modified ovsynch + CIDR protocol

The study was designed to compare the size of dominant follicle (DF) achieved, plasma progesterone decline and plasma estradiol level on the day of estrus and subsequent conception in buffaloes subjected to modified ovsynch-based regimen in buffaloes. In estradiol-based protocol (n = 15) on day 0 (beginning of experiment), buffaloes were administered controlled internal drug release (CIDR) device (1.38 g P4) and concurrently received 1.5 mg estradiol-17β in 1.5 ml canola oil (i.m.). On day 9, CIDR was removed and a PGF2α analogue (500 µg, i.m.) administered. On day 11, buffaloes were administered gonadotropin releasing hormone (GnRH) analogue (20 µg, i.m.) and inseminated on day 11 and day 12. Ovsynch-based group (control, n = 15) received GnRH on day 0 in place of estradiol-17β, CIDR insert for 7 instead of 9 days and the remaining protocol and insemination procedures were same as treatment group. The diameter of DF, plasma progesterone and estradiol levels were not different between the groups. The first service conception rate (FSCR) was higher (p < 0.05) in estradiol-based group than in control (53.33 vs. 33.33%, respectively). In conclusion, replacement of first GnRH with estradiol-17β in ovsynch plus CIDR protocol and increasing CIDR exposure by two days leads to higher FSCR.

Effects of melatonin supplementation prior to Ovsynch protocol on ovarian activity and conception rates in anestrous Murrah buffalo heifers during out of breeding season

Buffalo heifers have tendency to show anestrus during summer season. Melatonin has been used for correcting summer dependent anestrous via inducing resumption of ovarian activity. Therefore, the investigation was conducted to compare efficacy of melatonin for induction of estrus and conception rate with Ovsynch protocol in summer anestrous Murrah buffalo heifers. Thirty, summer anestrous Murrah buffalo heifers were selected and divided into two groups- treatment (n = 20; 12 melatonin implants) and control (n = 10; no treatment). On day 28 post-implant insertion, animals of both the groups were subjected to Ovsynch protocol. Blood sampling and ovarian ultrasonography were conducted to measure plasma melatonin, progesterone concentration and ovarian dynamics, respectively. No animal in either group showed estrus during first 28 days post-implant insertion. However, estrus induction rate was 100% after Ovsynch protocol in both groups. As compared to controls, treatment group exhibited higher (p < 0.05) plasma melatonin on days 1, 4, 8, 15, 22 and 28 post-melatonin, with highest concentration on day 4. The progesterone concentration increased (p < 0.05) on days 15 and 22 post-melatonin treatment. The treatment group had larger (p < 0.05) preovulatory follicle on day of AI, subsequently developed larger (p < 0.05) corpus luteum and higher plasma progesterone concentrations by day 12 post-AI as compared to the control group. The overall conception rate was 50 and 20% in treatment and control groups, respectively. In conclusion, melatonin treatment along with Ovsynch protocol improved the luteal profiles as well as the conception rate in buffalo heifers when compared with animals treated with Ovsynch protocol alone during summer season.

Circulating levels of estradiol 17-β and progesterone vis à vis nitric oxide and nitric oxide synthase at and around oestrus in cycling buffaloes

The present study was designed to measure the circulating levels of estradiol 17-β and progesterone vis à vis nitric oxide (NO) and nitric oxide synthase (NOS) levels at and around oestrus in cycling buffaloes. Blood samples were collected −2, −1, 0, +1 and +2 days of oestrus cycle from cycling buffaloes and analyzed for NO, NOS, estradiol 17-β and progesterone levels. In present study, the levels of NO did not show significant (P < 0.05) variation from −2 day to day of oestrus then decreased significantly and ranged between 11.4 and 26.4 μM/L. The NOS concentration showed similar pattern as exhibited by NO in buffaloes and ranged from 0.56 to 1.28 U/L. The estradiol 17-β in buffaloes gradually increased and peaked at day of oestrus and ranged between 1.9 and 29.32 pg/ml and the pattern was observed almost similar to those of NO and NOS. The levels of progesterone decreased from −2 day to day of oestrus and then increased and ranged between 0.01 and 0.42 ng/ml. The present study generates data of NO, NOS, estradiol 17-β and progesterone at and around oestrus in buffaloes and that is of practical importance for clinical and experimental interpretations.