Follicular characteristics and intrafollicular concentrations of nitric oxide and ascorbic acid during ovarian acyclicity in water buffalo (Bubalus bubalis)

Follicular Dynamics during Estrous Cycle of Pubertal, Mature and Postpartum Crossbred (Nili Ravi × Jianghan) Buffaloes

The follicular dynamics is used as a reliable indicator for reproductive management in livestock. However, the follicular dynamics (follicle wave emergence, estrus cycle length, diameter of dominant follicle, follicular growth and atretic phases) during the estrous cycle of crossbred (Nili Ravi-Jianghan) buffalo is still unexplored. Therefore, the present study aimed to observe the follicular dynamics in estrous cycle of crossbred buffaloes at different physiological stages (pubertal; n = 28, sexual mature; n = 22 and postpartum; n = 18). In the present study, the follicular dynamics were ultrasonically examined at 12 h intervals throughout an estrous cycle during the breeding season. The results indicate that about 86.76% (59/68) crossbred buffaloes, irrespective of physiological stage, exhibited two follicular waves in estrous cycle with an average estrus cycle length was 20.7 ± 0.4 days. The estrus cycle length was significantly shorter (p < 0.05) in pubertal buffaloes (19.4 ± 0.4 days) compared with sexual mature (21.5 ± 0.3 days) and postpartum (21.9 ± 0.4 days) buffaloes. The first follicular wave emerged on same day during one- (pubertal vs. postpartum), two- (pubertal vs. mature vs. postpartum) or three-wave (mature vs. postpartum) estrous cycle buffaloes. The maximum diameter of dominant follicle (DF) in pubertal, sexually mature and postpartum crossbred buffaloes was 9.6 ± 2.0 mm, 10.6 ± 0.5 mm and 12.6 ± 0.7 mm with growth rate of 1.08 ± 0.04 mm/day, 0.92 ± 0.04 mm/day, and 0.9 ± 0.07 mm/day, respectively. In conclusion, similar to other buffalo breeds, Nili Ravi-Jianghan crossbred buffaloes showed the two-wave follicular pattern dominantly with an average duration of ~20 days estrous cycle. The observed follicular dynamics can be used as a reliable indicator for synchronization and fixed-time artificial insemination (FTAI) programs to improve the fertility of crossbred buffaloes.

Effect of exogenous melatonin on endocrinological profiles, biochemical and antioxidant and oxidative stress profiles in post-partum anestrus Andaman local buffaloes (Bubalus bubalis) in tropical island ecosystem

Andaman local buffalo (ALB) is distributed in Andaman and Nicobar Islands. ALB is non-descriptive and represents admixture of different Indian breeds of buffaloes. ALB is suffering infertility due to anestrus in dry (summer) season. Therefore, this study was conducted to assess the effect of slow release subcutaneous exogenous melatonin (MT) implant on hematological profiles, endocrinological profiles (cortisol and prolactin), biochemical profile (total protein, albumin, globulin, glucose and total cholesterol), antioxidant profiles [total antioxidant capacity (TAC), catalase (CAT), glutathione (GSH) and superoxide dismutase (SOD)] and oxidative stress profile (malondialdehyde; MDA) in anestrus buffalo cows during summer to improve its reproductive efficiency. Experimental buffaloes (5–7 years of age) were selected and divided into two groups, Gr I: Control (n=6) and Gr II: Treatment (n=6; melatonin implant @ 18 mg/50 kg b.wt). Statistical analysis revealed that these experimental profiles differed significantly between treatment and control groups. Blood profiles revealed that anestrus buffalo suffered severe macrocytic hypochromic anemia with increased leukocytosis and MT has improved the health status of reproductive system and whole body systems. Concentration of cortisol and prolactin were lower in MT treated than in control group. Similarly, antioxidant profiles were higher and oxidative stress profile was lower in MT treated group than in control group. Biochemical profiles were increased in MT treated than in untreated buffalos. Study concludes that melatonin had significant beneficial effects in improvement of the antioxidant profiles, minimization of oxidative stress with cascading beneficial effects on hormone, biochemical and hematological profiles, which will improve the cyclicity and fertility rate in anestrus buffalo during summers in humid tropical island ecosystem.

Ameliorating postpartum reproductive cyclicity using exogenous melatonin implant in water buffalo (Bubalus bubalis)

This study was conducted to evaluate the impact of melatonin implants on oxidative stress levels and improving reproductive cyclicity in early postpartum buffalo. Total of 30 buffaloes at 15 days postpartum were randomly divided into melatonin treatment (n=15, one melatonin implant/50 kg body weight, 18 mg melatonin/implant) and control (n=15) groups. Both the groups were equally monitored for overt estrus signs and subjected to trans-rectal ultrasonography to check ovarian status. The blood samples were collected from jugular vein at weekly interval from day 15 to 43 post-partum to assess oxidative stress status. Significant reduction in concentration of malondialdehyde was observed in blood plasma from day 36 postpartum in treatment as compared to control buffaloes. The superoxide dismutase increased in treatment group from day 29 postpartum as compared to control. The concentration of glutathione reductase revealed nonsignificant difference between the groups. Treatment buffaloes showed higher oestrous exhibition rate (66.6% v/s 26.6%) with significant early onset of overt oestrus signs (24.10±1.49 days) compared to control (34.25±5.25 days). Ovulation rate was higher in treatment (n= 13; 86.66%) than that in control (n=8; 53.33%) buffaloes. In conclusion, melatonin implants efficiently reduced oxidative stress and resulted early resumption of ovarian activity, higher oestrus exhibition and ovulation rates in postpartum buffaloes.

Synchronization with controlled internal drug release (CIDR) and prostaglandin F2α (PGF2α) influences oxidant/antioxidant biomarkers and mineral profile in summer-stressed anoestrous buffalo (Bubalus bubalis)

During the summer season, high ambient temperature in tropical and subtropical countries exposes buffaloes to oxidative stress that have antigonadotropic and antisteroidogenic effects. Uses of hormonal therapy can improve the state of ovarian inactivity caused by heat stress and cause anoestrous buffaloes to come into oestrus and successfully achieve pregnancy. Therefore, this study was designed to detect the role of oxidative stress in production of the anoestrous state in summer heat stressed buffaloes and the effects of treatment by Controlled internal drug release (CIDR) in solving of this problem. Also it monitored the changes in Oxidant/antioxidant biomarkers and mineral profile before and after the treatment. Forty buffaloes with no signs of oestrus for more than 120 days after calving were selected. The animals were divided into two groups: the first group (group I, n = 25) was subjected to treatment with CIDR, while the second group (group II) received no treatment and was considered the control group (n = 25). Blood samples were collected before treatment, after treatment and after 45 days of oestrus. The serum level of TAC, MDA, NO, ascorbic acid (vitamin C), P, Cu and Zn were measured. The results showed that 80% of treated buffaloes came into oestrus. The conception rate was 75%. TAC concentrations were significantly higher in group I than in group II. There were significant decreases in the mean values of MDA, NO and ascorbic acid in the buffaloes in oestrus, but these values increased when the buffaloes became pregnant. In contrast there were no significant differences in the mean values of MDA, NO or ascorbic acid in the buffaloes that came into oestrus but failed to conceive. The mean serum P, Cu and Zn values were significantly increased (P < 0.05) in the buffaloes that came into oestrus compared to the control animals. The levels of P and Zn significantly increased when the buffaloes became pregnant and remained unchanged when they failed to conceive. In conclusion, known physiological and pathological variations in the oxidant/antioxidant parameters and mineral profile of summer anoestrous buffaloes may help to understand this problem of infertility.

Investigation into homocysteine [corrected], vitamin E and malondialdehyde as indicators of successful artificial insemination in synchronized buffalo cows (Bubalus bubalis)

The aim of this study was to describe modifications in plasma homocysteine (Hcy), vitamin E (VitE) and malondialdehyde (MDA) concentrations in the first 56 days after artificial insemination (AI) in buffalo. Thirty-five buffalo cows were divided, ex post, into three groups on the basis of pregnancy diagnosis: pregnant, not pregnant, with embryonic mortality. Pregnancy was diagnosed by ultrasonography and plasma concentrations of pregnancy-associated glycoproteins (PAGs). Our results showed that, in pregnant buffaloes, included those with embryonic mortality, MDA increased progressively while VitE decreased. In non-pregnant buffaloes, MDA and Vit E were unchanged. Hcy concentrations also remained unchanged within each group throughout the study period, but were lower in non-pregnant buffaloes than in the pregnant ones and in those with embryonic mortality. In conclusion, present data suggest that successful pregnancy in buffalo cows might be linked to Hcy metabolism and oxidative stress involvement.

Endometritis impairs luteal development, function, and nitric oxide and ascorbic acid concentrations in buffalo (Bubalus bubalis)

A vast majority of the world buffalo resource is concentrated in tropical and subtropical countries. Apart from heat stress and poor nutritional availability, endometritis is one of the most commonly encountered reproductive problems limiting fertility and consequently productive potential of the species. As demonstrated recently, endometritis impairs growth and follicular fluid composition of the largest follicle in buffalo. In the present study, the effect of endometritis on luteal development, function, nitric oxide (NO), and ascorbic acid was investigated. Reproductive tracts were collected from 90 cyclic buffaloes at an abattoir and grouped into endometritic (n = 36) or non-endometritic (n = 54) buffaloes based on physical examination of uterine mucus, white side test, and uterine cytology. Samples with pus-containing mucus, positive reaction on white side test, and/or >5 % neutrophils were considered to be positive for endometritis. Corpora lutea were enucleated, weighed, classified into stages I to IV, and assayed for progesterone (P(4)), NO, and ascorbic acid concentrations. Endometritic buffaloes had lesser (P < 0.0001) luteal weight and P(4), NO, and ascorbic acid concentrations than non-endometritic buffaloes. The findings indicated that endometritis impairs corpus luteum development and function in buffalo. Reduced luteal NO and ascorbic acid concentrations during endometritis are novel findings.

Biology and biotechnology of follicle development

Growth and development of ovarian follicles require a series of coordinated events that induce morphological and functional changes within the follicle, leading to cell differentiation and oocyte development. The preantral early antral follicle transition is the stage of follicular development during which gonadotropin dependence is obtained and the progression into growing or atresia of the follicle is made. Follicular growth during this period is tightly regulated by oocyte-granulosatheca cell interactions. A cluster of early expressed genes is required for normal folliculogenesis. Granulosa cell factors stimulate the recruitment of theca cells from cortical stromal cells. Thecal factors promote granulosa cell proliferation and suppress granulosa cell apoptosis. Cell-cell and cell-extracellular matrix interactions influence the production of growth factors in the different follicular compartments (oocyte, granulosa, and theca cells). Several autocrine and paracrine factors are involved in follicular growth and differentiation; their activity is present even at the time of ovulation, decreasing the gap junction communication, and stimulating the theca cell proliferation. In addition, the identification of the factors that promote follicular growth from the preantral stage to the small antral stage may provide important information for the identification for assisted reproduction techniques.