Effect of 17 beta-estradiol on ferminization of Thai silver barb (Puntius gonionotus Bleeker)
1998
Samnao Saowakoon
Study on sex reversal to female by oral administration of 17 beta-estradiol hormone was conducted in Thai silver barb (Puntius gonionotus). Four doses of the hormone 50, 100, 150 and 200 mg hormone/kg feed were tested. The treatment initiated the at age of 2 weeks, treatment duration was 30 and 60 days. A dose of 50 mg/kg gave the highest percentage of female and there were no differences between durations of 30 and 60 days. When dosages of 30, 40, 50, 60 and 70 mg hormone/kg feed were used highest percentages of female fish were obtained in the groups received 50 or 60 mg hormone/kg feed (76.67 and 78.80 percentage respectively). Percentages of intersex fish were not different between these two groups (4.44 and 3.33 percentage respectively), but percentage of sterile fish was significantly higher in the group treated with 60 mg hormone/kg feed than 50 mg hormone/kg feed group (8.89 and 3.33 percentage respectively). The experiment on comparison of growth of hormone treated fish and the untreated control was done using doses of 40 and 60 mg hormone/kg feed, treatment initiated at 2 weeks post hatched and lasted for 30 days. Each experiment group was stocked separately in earthen ponds with 3 repplicates. The experiment started when the fish were 60 days old and finished at 210 days old. Results revealed that the group received 60 mg hormone/kg feed reached the biggest size (body weight = 162.24+-4.51 g and body lenght = 21.19+-0.63 cm) and was statistically differents from control group (body weight = 110.07+-13.59 g and body lenght = 18.24+-1.44 cm). The group received the 60 mg hormone/kg feed comprised of 78.66 percentage of female fish was 46.67 percentage in the control.
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