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Kumar A.,ICAR Res Complex for NEH Region | Mehrotra S.,Indian Veterinary Research Institute | Singh G.,Indian Veterinary Research Institute | Narayanan K.,Indian Veterinary Research Institute | And 6 more authors.
Theriogenology | Year: 2015

High ambient temperature during summer in tropical and subtropical countries predisposes water buffaloes (. Bubalus bubalis) to develop oxidative stress having antigonadotropic and antisteroidogenic actions. Melatonin is a regulator of seasonal reproduction in photoperiodic species and highly effective antioxidant and free radical scavenger. Therefore, a study was designed to evaluate the effect of sustained-release melatonin on biomarkers of oxidative stress i.e., the serum malondialdehyde (MDA) and nitric oxide (NO), and the total antioxidant capacity (TAC). For the study, postpartum buffaloes diagnosed as summer anestrus (absence of overt signs of estrus, concurrent rectal examination, and RIA for serum progesterone) were grouped as treated (single subcutaneous injection of melatonin at 18mg/50kg body weight dissolved in sterilized corn oil as vehicle, n=20) and untreated (subcutaneous sterilized corn oil, n=8). Blood sampling for estimation of serum TAC and MDA (mmol/L) and NO (μmol/L) was carried out at 4days of interval from 8days before treatment till 28days after treatment or for the ensuing entire cycle length. Results showed serum TAC concentration was higher in the treatment group with a significant (P<0.05) increasing trend, whereas MDA and NO revealed a significant (P<0.05) decline. Serum MDA and NO were higher in control compared with those of treatment group. Moreover, buffaloes in the treatment group showed 90% estrus induction with 18.06±1.57days mean interval from treatment to the onset of estrus. These results report that melatonin has a protective effect by elevating antioxidant status and reducing oxidative stress resulting in the induction of cyclicity in summer-stressed anestrous buffaloes. © 2015 Elsevier Inc. Source


Kumar A.,ICAR Res Complex for NEH Region | Mehrotra S.,Indian Veterinary Research Institute | Singh G.,Indian Veterinary Research Institute | Maurya V.P.,Indian Veterinary Research Institute | And 8 more authors.
Reproduction in Domestic Animals | Year: 2016

Contents: The role of melatonin as a protective neurohormone against restoring cyclicity in summer anoestrous animals in photoperiod species has gained wider acceptance. This study was designed to uncover the evidence the slow-release melatonin (MLT) has on initiation of ovarian cyclicity and conception rate (CR) in summer anoestrous buffaloes. Thus, buffaloes diagnosed as summer anoestrous (absence of overt signs of oestrus, concurrent rectal examination and radioimmunoassay for serum progesterone at 10 days interval) were grouped as untreated (Group I, sterilized corn oil, n = 8) and treated (Group II, single subcutaneous injection of MLT @18 mg/50 kg bwt in sterilized corn oil, n = 20). Animals treated and detected in oestrus were artificially inseminated (AI) followed by division into Group III (second dose of MLT on 5th day post-AI, n = 8) and Group IV (no melatonin administration, n = 10). Blood samples were collected at 4 days interval for estimation of serum MLT, progesterone and oestrogen using radioimmunoassay kit. Mean oestrous induction rate (OIR), oestrous induction interval (OII), interoestrous interval (IOI) and CR were estimated. Compared to control, concentration of melatonin was significantly (p < 0.05) higher in treated group ranging from 14.34 ± 1.72 to 412.31 ± 14.47 pg/ml whereas other two hormones did not show any concentration difference. Melatonin-administered buffaloes showed significantly (p < 0.05) higher (90%) OIR with OII of 18.06 ± 1.57 days. Results showed improvement in conception rate in buffaloes administered with post-insemination melatonin. It can be concluded from the study that slow-release melatonin supplementation restored cyclicity in summer anoestrous animals resulting in improvement in conception rate in buffaloes. © 2016 Blackwell Verlag GmbH. Source

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