Growth Performance of Nile tilapia Immersed in 17α-methyltestosterone and rElGH, and Fed a Diet Enriched with rElGH

Abstract

The aim of the present study was to investigate the growth performance of Nile tilapia immersed in 17α-methyltestosterone (MT) and recombinant giant grouper growth hormone (rElGH), and fed a rElGH-enriched diet. A total of 200 tilapia larvae aged 10 days and 14 days post hatching was immersed in 1 liter of 30 g/L saline water for 3 minutes, then in freshwater containing either MT, MT+rElGH, or rElGH for 4 hours. The MT dose was 2.0 mg/L and rElGH was 2.5 mg/L. As control was treatment without MT and rElGH. Fish were maintained in 250-L aquariums for 6 weeks and then moved to net cages for 8 weeks of rearing. The rElGH-enriched diet was fed to the 6-week-old fish for a month, and then fed a non-enriched diet. Each treatment was triplicates. The result showed that the daily growth rate (DGR), biomass gain (BM), survival (SR) and feed (artemia nauplii) consumption during maintenance in the aquariums in the rElGH and MT+rElGH treatments were higher (P<0.05) than in the control. The higher DGR and BM at net cage rearing and lower feed conversion ratio (P<0.05) were also found in MT and MT+rElGH treatments. None of the treatments showed any difference in survival (P>0.05). Profits estimation in the MT and MT+rElGH treatments were 63.38% and 57.91% higher than the control. The present study concluded that higher Nile tilapia farming performance could be obtanied by MT immersion in the larval phase and feeding juvenile on the rElGH-enriched diet.

Masculinization of Banggai Cardinalfish (<i>Pterapogon kauderni</i>) using 17α-Methyltestosterone-enriched <i>Artemia</i> sp.

“…which had been soaked with the 17α-Methyltestosterone (17α-MT) hormone for all treatments was not significantly different (P>0.05) from the control (Table 1). Similar results have also been reported by Safir et al (2017) using tilapia larvae aged 10 and 14 days soaked with the 17α-MT hormone for 4 hours and kept for six weeks. In another study, using the oral method on tilapia larvae aged 16 days with a duration of 28 days and kept for two months (Safir, 2018).…”

“…The parameters observed in the study included: daily growth rate measured every two weeks according to the method used by Safir et al, (2017). Furthermore, biomass gain and survival rate was measured at the beginning and end of maintenance by referring to the method used by Safir (2018).…”

“…The sex samples observed were only five fish for each treatment because of endemic fish. Observations were carried out using the acetocarmine method (Chakraborty et al, 2011;Safir et al, 2017) and observed under a microscope (Primo star brand magnification 40x).…”

“…During the incubation process, the male did not consume food and causes shrinkage of body weight, as occurs in the brood stock female tilapia (Safir et al, 2017). This will certainly have an impact on the spawning cycle in the next stage and make the time longer because the male needs time to recover physiologically.…”

“…Sex reversal using the hormone 17αmethyltestosterone (17α-MT) is one way that can be done to produce male androgynous fish (Chakraborty et al, 2011;Safir et al, 2017). The mechanism of this hormone is to inhibit the activity of aromatase in the formation of androgen hormones into estrogen, so that androgen levels are higher and cause phenotypic changes in test fish so that it resembles males as occurs in tilapia (Zairin, 2002;Safir et al, 2017). One method that can be used in the application of the 17α-MT hormone is through artificial feed (Carman et al, 2008;Safir, 2018).…”