Effect of Treatment Duration on Ultrasound cum 17ß, Methyl Testosterone Immersion masculin Technique of Nile Tilapia (Oreochromis niloticus L) Fry

Abstract

The objective of this study was to explore the effect of treatment duration on ultrasound cum 17ß-methyi testosterone immersion technique of sexually undifferentiated Nile Tilapia fries to produce all male mono-sex population in 1.5h and 2.Oh. A 50 fries density of three treatment groups were immersed in one litre of 100 pg/L 17-ß, methyl testosterone hormone solution with and without cavitation level ultrasound, without hormone immersion ultrasound only along with the control group of which neither hormone immersed nor ultrasound received in both treatment duration. Hormone immersion with ultrasound in two hours duration produced significantly higher effect (p<0.05) on percentage of males 92.02 ± 0.80 (mean ± SD) and the mean survival rate of 83.67±1.53 (mean SD), where as the 1.5h duration produced 83.00±0.68 (mean ± SD) percentage of males. Ultrasound application alone without hormone solution also, produced higher male percentages of 81.36±0.65 (mean ± SD) and 79.77±1.34 (mean ± SD) in 1.5h and 2.0h treatment durations respectively, than the hormone immersion only without receiving ultrasound application which produced 77.86±1.7 (mean ± SD) and 78.55±0.24 (mean ± SD) male percentage in 1.5h and 2.0h treatment durations respectively. All treatment groups produced significantly higher (p<0.05) results than the control group which neither received hormone-immersion nor ultrasound produced 56.59± 2.75 (mean ± SD) and 56.26 ± 0.82(mean ± SD) percentage of males in both 1.5h and 2.0h treatment durations respectively. This study indicated that 50 fries/L unit in an ultrasound cum 17- (3, methyl testosterone hormone immersion for 2.Oh duration would be commercially viable than the previous protocols recommended and this protocol would be adapted by farmers as an alternative for 2 Id nursery phase dietary administration of 30mg/kg 17- ß, methyl testosterone.