Abstract

In the context of guppies (Poecilia reticulata), male fish are considered more attractive and valuable. The majority of mono-sex production in male fish employs the use of 17α-methyltestosterone, an expensive hormone with limited supply. It is therefore necessary to explore the potential of natural ingredients as an alternative replacement, such as purwoceng (Pimpinella alpina). The objective of this study was to determine the optimal immersion duration for the masculinization of P. reticulata. This study employed a completely randomized design with four treatments of immersion duration (0, 8, 10, and 12 h), with three replications allocated to each treatment. Following immersion, the guppy larvae were reared for a period of 45 days and fed with Daphnia sp. and Artemia cysts. The sex of each fish was determined through surgical procedure at the conclusion of the larval rearing period. The findings revealed that the duration of larval immersion in P. alpina extract had a notable impact (P < 0.05) on the proportion of male fish. In this study, the 10-h immersion treatment yielded the highest number of male P. reticulata, at 83.33%. The results of this study are highly valuable for the application of sex reversal techniques using phytosterol as a replacement for synthetic hormones.

Key words: mono sex culture, phytosterol, purwoceng, sex reversal, stigmasterol