This study assessed the efficacy of Basella alba leaf extract in the sex reversal of Nile tilapia Oreochromis niloticus using egg immersion, oral administration and fry immersion techniques. Efficacy of B. alba was compared to the efficacy of the 170-methyltestosterone.

The experimental fish seeds were randomly distributed to eight (8) treatments, replicated three (3) times. Each replication contains 60 eggs and fry. Aqueous extract for egg and fry immersion was prepared by boiling whereas leaf extract for oral administration was prepared by ethanol extraction.
Egg immersion was performed by immersing yellow eggs in hormone solutions for 96 hours while fry immersion was completed by immersing the experimental fish in the hormone solutions every seven days for 28 days for 2 hours starting from the yolk-sac fry stage. On the other hand, oral administration was completed by feeding the experimental fish with hormone treated feeds for 28 days, starting from the time of complete yolk absorption.

ALEB recorded the highest survival rate (58.89%) in the egg immersion treatment (p<0.01) while lowest (13.33%) was from the 17a-methyltestosterone treatment. In the fry immersion and oral administration techniques, highest survival rate (22.22%) was recorded in the negative control (p<0.01) with lowest at 170-methyltestosterone (13.33%).

Highest percentage male in both oral administration (74.74%) and egg immersion (82.61%) techniques was obtained in the treatment using 17a-methyltestosterone followed by ALEB with 64.96% and 80.18% males, respectively. On the other hand, highest percentage male (75%) in fry immersion technique was observed in the treatment using ALEB, followed by 17a-methyltestosterone with 70% male. The result of the present study revealed no significant difference between ALEB and 17a-methyltestosterone which suggests that ALEB can be used in the sex reversal of Nile tilapia with the same effect as the 17a-methyltestosterone Basella alba can therefore be used as an alternative source of hormone, in place of the 17u-methyltestosterone which is commonly used in the sex reversal of Nile tilapia Moreover, the use of egg immersion technique in the sex reversal of Nile tilapia using Basella alba can achieve higher percentage of male compared to oral administration and fry immersion techniques.

Thesis (Doctor of Veterinary Medicine)

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