FRI makes breakthrough in tiger grouper breeding using 'ubi gadong'.
The method, believed to be the first of its kind in the country, involves the use of the 'ubi gadong' ('Intoxicating Yam') as a hormone treatment for the maturity of the gonads, the reproductive organ in the parent fish.
(The groupers are mostly monandric protogynous hermaphrodites, that is, they mature only as female and have the ability to change sex after sexual maturity)
This latest finding in the marine fish breeding field enables the female parent fish to produce more eggs to obtain fish seeds.
Previously, the method had been carried out in Mexico, but only for the production of hormone steroids for human usage.
The 'Intoxicating Yam' (scientific name: Dioscorea hispida) is a creeper plant which contains poison which can be found in 19 other plant species.
This yam variant which grows in the wild can reach up to 20 metres high. Its yellow skin is rough and thin and its flesh, yellowish-white.
For some in Malaysia, the yam plant is made into a food product by removing its toxic content.
A senior researcher at the Tanjung Demong FRI, Dr Ahmad Daud Om, has successfully extracted the yam variant's toxic compound known as discorine.
The discorine, a type of alkaloid that dissolves in water during the production of steroid diosgenin, was found to be effective in the release of fish breeding hormones.
The steroid diosgenin extracted from the plant is a crucial element in the production of hormones which contributes to the maturity process of the fish.
'I started my research on the findings called i-gADO from 2016 on 50 tiger groupers at FRI,' said Ahmad Daud when met by Bernama at the centre today.
He said the study was conducted following problems faced by the centre, namely the inconsistent supply of grouper seeds, the production of low-quality eggs from the female parent fish and the costly dependency of parent stock from outside.
'To overcome these problems, we sought a method to stimulate the production of an extract from the gadong tuber to produce a solution that could be made into capsules to boost hormones in the fish that are cost-savvy and effective.
'From 50kg of processed gadong tuber, a 300gm mixture is produced and made into capsules for fish feed,' he explained.
He said prior to the discovery, synthetic hormones that were costly had to be used to spur the maturity of gonads in female groupers.
'Each synthetic injection weighing 15,000 IU (international unit) costs RM200, and two to three shots are needed for female parent groupers weighing between three and five kilogrammes within a period of several hours. This means that the costs incurred for each fish can reach up to RM1,200 (depending on the weight of the fish)', noted Ahmad Daud.
Meanwhile, he said, the gadong tuber capsules only cost RM3 each and were fed to the female grouper thrice a week, for a period of two months, with total cost at only RM70 for each fish.
Dr Ahmad Daud added that with consumption of i-gADO, the abdomen of the female parent grouper would enlarge within 30-40 days, indicating their hormone level had increased and the formation of eggs had started.
He said the i-gADO method was also easier to manage and reduced the stress experienced by the parent grouper which increased egg production.
The senior researcher said studies using the method would be continued and was optimistic that the problems faced by the Tanjung Demong FRI would be overcome by the middle of this year.
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|Publication:||Malay Mail Online (Petaling Jaya, Malaysia)|
|Date:||Jan 26, 2018|
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