Reproductive Biotechnologies for Improvement of Buffalo: The Current Status

Abstract

Reproductive biotechnologies continue to be developed for genetic improvement of both river and swamp buffalo.Although artificial insemination using frozen semen emerged some decades back, there are still considerable limitations. The major problem appears to be the lack of efficient methods for estrus detection and timely insemination. Controlled breeding experiments in the buffalo had been limited and similar to those applied in cattle. Studies on multiple ovulation and embryo transfer are essentially a replica of those in cattle, however with inherent problems such as lower number of primordial follicles on the buffalo ovary, poor fertility and seasonality of reproduction, lower population of antral follicles at all stages of the estrous cycle, poor endocrine status and a high incidence of deep atresia in ovarian follicles, the response in terms of transferable embryo recovery has remained low with 0.51 to 3.0 per donor and pregnancy rates between 15 to 30%. In vitro production of buffalo embryos is a valid alternative to recovery of embryos by superovulation. This aspect received considerable attention during the past decade, however the proportion of embryos that develops to the blastocyst stage is still around 25-30% and hence the in vitro culture procedures need substantial improvement. Embryo cryopreservation procedures for direct transfer post thaw need to be developed for bubaline embryos. Nuclear transfer and embryo cloning is a technique that has received attention in various species during recent years and can be of immense value in buffaloes as they have a low rate of embryo recoveries by both in vitro and in vivo procedures. Gender pre-selection, genome analysis, gene mapping and gene transfer are a few of the techniques that have been studied to a limited extent during recent years and are likely to be included in future studies on buffaloes. Very recently, reproductive biotechnologies have been applied to feral buffaloes as well, but the results obtained so far are modest. When fully exploited they can play an important role in the preservation of endangered species.

Current Status of animal biotechnology and option for improvement of animal reproduction in Asia

“…The birth of the first calf through embryo transfer was achieved by Betteridge (Betteridge, 2006). Although super ovulation in buffalo started three decades ago the first live calves from bubaline embryos were born in1983 in the USA and later in India (Purohit et al, 2003). Studies on superovulation among buffaloes have been carried outboth in the river and swamp buffaloes in various countries including India (Nandi et al, 2002).…”

“…Earlier attempts were reported from South East Asia (Thailand) and Bulgaria with modest results due to peculiarities inherent to the buffalo. Multiple Ovulation and Embryo transfer (MOET) optimizes the female contribution to genetic progress and it increases genetic gain by 63 to 70% per year from juvenile and adult buffalo compared to progeny testing (Purohit et al, 2003). The in vivo procedures involve induction of multiple ovulation, breeding and non-surgical recovery of embryos which are then transferred to synchronized recipients Inherently poor reproduction and seasonality in buffalo warrants the use of advanced reproductive technologies in this species.…”

“…Cloned embryos produced from nucleus transfer of buffalo fetal and adult somatic nuclei into enucleated bovine oocytes and subsequent development to the blastocyst stage has been reported (Kandil et al, 2014). Most previous studies have utilized adult or fetal fibroblasts as nucleus donors (Misra and Tyagi, 2007) however, some of the more recent reports depict the successful production of cloned embryos by nucleus transfer from cells other than fibroblasts such as somatic cells isolated from urine (Jain et al, 2011) amniotic fluid derived stem cells (Purohit et al, 2003) and somatic cells from milk (Zhang et al, 2011).…”

Advances in reproductive biotechnologies

“…[ 26 ], and subsequently, first bovine calf (Holi) was produced at ICAR-National Dairy Research Institute. OPU has advantage to collect oocytes from animals with less invasiveness and the use of superior animals as oocyte donors in embryo transfer [ 27 ]. This method not only increases the lifetime reproductive efficiency but also can be used in follicle ablation for aiding follicle turnover during embryo transfer protocol.…”

Vitrification of immature bubaline cumulus oocyte complexes by the open-pulled straw and conventional straw methods and their subsequent in vitro fertilization

“…Buffalo oocyte cryopreservation can be important because of the relatively lower oocyte yield per ovary (Purohit and Sharma, 2002;Purohit et al, 2003) however, the cryopreservation protocols need substantial improvement. The objective of the present study was to vitrify bubaline oocytes using conventional straw and OPS methods with two cryoprotectants in order to determine the optimum cryoprotectant and vitrification method.…”