Masculinization of featherfin squeaker Synodontis eupterus Boulenger, 1901 larvae using javanese long pepper extract Piper retrofractum and increased rearing temperature

Abstract

Javanese long pepper (Piper retrofractum) is known to have androgenic effect, could act as phytosteroid and alternative to masculinization. This research aimed to evaluate the optimum dose of the Javanese long pepper extracts combined with increased rearing temperature on featherfin squeaker masculinization through larva immersion. This research was designed using a completely randomized design with 8 treatments consisted of Javanese long pepper extract doses of 0.0625 mg L-1and 0.125 mg L-1, negative control (without both extract and 17α-metiltestosterone) and positive control (2 mg L-117α-metiltestosterone). Each of them consisted of two different temperature treatments, namely, normal (26-27ᴼC) and 32ᴼC. After five hours treatment, larvae were reared until five months age. The fish age four and then five months were dissected and their gonads were taken for acetocarmine and histology preparation. Beside that the percentage of fish survival, body length, weight gain, and specific growth rate were also recorded in certain period. The result showed that the Javanese long pepper extract dose at 0.125 mg L-1 with normal temperature treatment produced the highest male ratio and significantly different compare with control. Giving this dose to larvae did not affect fish survival and growth, meanwhile increased temperature treatment could not increase the effectivity of Javanese long pepper extract.