In a ground breaking work, the Fisheries Research Centre of Assam Agricultural University (AAU) has observed the amazing regeneration of the dissected testis of a male catfish (Clarias batrachus) popularly known as Magur.
Bibha Chetia Borah, principal scientist and officer in-charge of the Centre said that this would prevent the mutilating and killing of male Magurs for breeding purpose as was the practice and that the conceptual understanding of the natural mechanism of regeneration in such animals will pave the way for developing novel regenerative medical strategies for treatment of traumatic injuries in people as humans do not have this regenerative capability.
The Asian catfish known as Magur in Assam is one of the most important native food fish species. Traditionally, this fish is used for therapeutic purpose in curing anemic or convalescing patients as well as to lactating mothers.
Chetia Borah said that the Magur had a specialized organ for breathing atmospheric oxygen which made it capable of remaining alive for many hours out of water.
“This air-breathing capacity of the fish helps traders to market the fish alive and hence fetches a higher market price in comparison to carps and other commercially important food fishes. In Assam, the market price of the species is as high as Rs 500 to Rs 1000 per kg during different seasons of the year,” she said.
The scientist further said that although the fish was in high demand, the culture of the species had not been geared up due to non-availability of seed and moreover they were also fast disappearing in the marshes of Assam due to large scale consumption.
“In order to popularise the culture and breeding of Magur, the seed production of this species through artificial breeding has been carried out at the Fisheries Research Centre under the Mega Seed Project, funded by ICAR, since 2006. However, there is an inherent problem with this technology for which the farmers exhibit reluctance for adoption of same,” said Borah.
Boarh added, “The technology of artificial breeding of Magur which is in vogue since 2005 requires stripping of the female and dry fertilization with the sperm solution of the male, for which the males are to be dissected to take out the testis. In the process of dissection, the males do not survive and are not in marketable condition which is why this technique is questionable whether it is economically and ecologically viable.”
A trial on refinement of Magur breeding technology under Mega Seed Project was conducted at the Centre, with some variations from the recommended technology which included the probability of keeping the males alive after dissection.
What the scientist observed over a period of two years was the regeneration of the testes which had been dissected out to for seed purpose artificially with the female eggs.
“After removal of the testes, the opening is tapped gently with fingers and then the fish was kept undisturbed in tanks in about 20 cm depth of water for 40 days. Observations of behaviour of the fish, mortality, secondary infection, healing, duration of survival, etc. along with water quality parameters were recorded. It was observed that around 90 pc of the fishes remained alive. More surprisingly, it was observed that without any stitching or without any medication, the slit in the abdomen started healing after four to five days. No abnormal behaviour was observed in the fish during these days,” the scientist added.