The Effectivity of Bull Testes Meal Extract on Sex Reversal Nile Tilapia, Oreochromis niloticus By Immersion Technique

Abstract

Monosex fish stocks are desirable in aquaculture in order to control reproduction and select the gender that have faster growth characteristics in a particular species. Synthetic steroids are commonly used to sex-reverse tilapia but because of their potential hazards and not recommended in Indonesia; the use of new natural compound is a potential alternative to be explored. Bull testes meal extract (BTME) had knowed containing natural testosterone hormone which can used on sex reversal in fish. The objective of this study was to determine the efficacy of a short-term immersion procedure for masculinizing Nile tilapia,_Oreochromis niloticus. Two androgens hormone were evaluated: 17a-methyltestosterone as control part (synthetic androgens) and the other is BTME as natural androgen. Exposure (8 h) on 4 and again on 7 days post-fertilization to 17a-methyltestosterone at 500 μg/ l successfully masculinized fry in all replicated experiments, resulting in 81,11% respectively. Immersions in BTME at 1 ml/l (Experiments A) resulted in significantly skewed sex ratios in (68,89 %), and Experiments B (3 ml/l) resulted in 75,56 % males; and Experiments C (5 ml/l) resulted in 85,56 % males. Although further research and refinement is needed, immersion of Nile tilapia in BTME may provide a practical alternative to the use of natural steroid-treated immersion. Furthermore, when compared with current techniques for steroid-induced sex inversion of tilapia, short-term immersion reduces the period of time that workers are exposed to anabolic steroids.