Preliminary Investigation of <i>Tribulus terrestris</i> (Linn., 1753) Extracts as Natural Sex Reversal Agent in <i>Oreochromis niloticus</i> (Linn., 1758) Larvae

Abstract

Synthetic sex reversal hormone used in controlling Tilapia population under culture condition has a perceived public health risk. This study therefore examined the prospect of utilization Tribulus terrestris as sex reversal agent in Oreochromis niloticus . Five pairs of Oreochromis niloticus (350±25.8) g in a ratio of 1:1 male to female were used for fry production. Four hundred and fifty day-old fry were randomly distributed into 18 experimental tanks (30 L capacity) and fed 50% crude protein diets containing 0.0 g, 1.0 g, 1.5 g, 2.0 g, and 2.5 g per 1 kg of basal feed of T. terrestris extract. Diet six contained 50 mg/kg of basal feed of 17-α-methyltestosterone served as control. Data collected includes, water quality (Temperature, pH and Dissolved oxygen), Growth performance (Mean Weight Gain (MWG), Food Conversion Ratio (FCR) and Specific Growth Rate (SGR)), survival rates at the fry and fingerlings stage and sex ratio. Data collected were subjected to 2-way analysis of variance. Temperature and pH ranged between 26 ℃ to 28 ℃ and 7.7 to 8.2 respectively. Dissolved oxygen varied from 5.13 mg/L to 9.12 mg/L. The mean weight gain of fry ranged from (0.73±0.08) g to (0.92±0.1) g and fingerlings from (14.35±1.26) g to (18.29±1.59) g which was significantly different across the treatments (p<0.05). FCR recorded for fry ranged from 1.53±0.17 to 2.12±0.14 and SGR, from 14.477±0.15 to 15.257±0.25. There was no significant difference in FCR and SGR across the treatments for fingerlings. Survival rates ranged from 80% to 89.3%. Percentage of males in treated fish increased as concentration of T. terrestris increased with T5-2.5g (85.7±1.3) %.