Development of Induced Breeding Technique for Freshwater Fish Gobi, Glossogobius giuris (Hamilton, 1822) Using Pituitary Gland (PG) Extract

This study aimed to establish induced breeding technique of freshwater fish gobi (Glossogobius giuris), using the pituitary gland (PG) extract. Six experiments were conducted at the Department of Fisheries Biology and Genetics, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh, Bangladesh. First breeding trial was conducted in June using 40, 45, and 50 mg PG kg-1 body weight of the female fish. None of the fish was ovulated in the 1st trial. Two more breeding trials were conducted in July and August, using 6 mg (T1), 8 mg (T2) and 10 mg (T3) PG kg-1 body weight of female, and 3 mg (T4), 4 mg (T5) and 5 mg (T6) PG kg-1 body weight of male fish. After treatment, the ovulation rates were recorded as 56.33±1.53, 82.67±2.52 and 75.33±1.53% in July and 58.00±2.65, 94.67±1.53 and 78.33±1.53% in August under the treatments T1, T2 and T3, respectively. Hatching rates of eggs were observed as 52.00±4.36, 81.67±3.21 and 72.33±6.03% in July, and 54.67±3.23, 91.67±3.06 and 73.67±5.13% in August under the T1, T2 and T3, respectively. Hatching time was ranged from 35 to 48 h and after the absorption of yolk sac (60-72 h), they were survived well when fed with tubificid worms and mixed zooplankton. The female treated with the dose of 8 mg PG kg-1 body weight in August showed the best performance so far as the ovulation, fertilization and hatching rates were concerned, while the single dose of 4 mg kg-1 body weight of PG was found to be effective for male fish in both months. The findings obtained from the present study reveals that induced breeding of G. giuris, using PG extract is successful for large scale production of quality seed in captive condition, which would further facilitate towards the aquaculture production and biodiversity conservation of this important fish species to a greater extent.