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Gender Reversal in Tilapia Fish to Increase Production

18 February 2013

OMAN - To increase the production of farm-raised tilapia, the Ministry of Agriculture and Fisheries (MoAF) has turned to sex reversal in the fish.

'Super males' are being produced through genetic engineering so that when they are bred with females, all the offsprings are males, reports Muscat Daily.

The reason for working on male tilapia population is that males grow faster, are larger and fleshier and hence, more in demand among consumers.

“Moreover, males need less feed unlike female tilapias. This means less production costs,” said Dr Fahad S Ibrahim, director of the Aquaculture Centre under MoAF.

“Our aim is to generate male tilapias for consumption without the use of any harmful substances. That is why we went for a genetic engineering technique for sex reversal in the fish or in other words, to get transsexual fish. The end result is the supermale (YY chromosomes).”

Breeding between a normal male (XY chromosome) and female (XX chromosome) tilapia doesn’t essentially lead to only male fry.

“Half of the fry could be females. The male fry are given a particular diet for some days which makes them phenotypic female (which look like females but are genetically males).

“Since these phenotypic females are capable of producing eggs, they are mated with normal males to produce a batch of fry containing 75 per cent males, thus diminishing the number of female offspring. Males from this batch when mated with female tilapias produce only male offsprings,” he said.

Funded by the Agriculture and Fisheries Development Fund (AFDF) under MoAF, the Aquaculture Centre has started developing a local hatchery for tilapia in collaboration with farmers.

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