Abstract
Experiments were conducted on production of some live food organisms using poultry waste for feeding fish fry between November, 2004 and December, 2007 in the Department of Aquaculture, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. Live food organisms viz., maggot, chironomid larvae and Spirulina platensis were produced by using an inexpensive but a potential media, poultry waste media (PWM). Maggot was cultured in PWM for a period of 7 days. Chironomid larvae were cultured in the residue of PWM after maggot grown for a period of 40 days. Both of them were cultured in three different treatments viz., T1, T2 and T3 each with three replications. The highest production rates of maggot and chironomid larvae were 19.91 and 26.15 g/kg PWM respectively in T1 and T2. The lowest production rates of maggot and chironomid larvae were 18.58 and 20.57 g/kg PWM respectively in T2 and T3. Proximate composition (% dry matter, % crude protein, % crude lipid, % ash, % NFE) of maggot and chironomid larvae and PWM at its different stages was analysed. Growth performance and proximate composition of maggot and chironomid larvae showed the significant differences (p<0.05) among all the treatments. In case of PWM it was significantly indifferent (p>0.05) before being used as culture, but after maggot and chironomid larvae grown showed the significant differences (p<0.050) among all the treatments. S. platensis was cultured in three different concentrations of the residue of poultry waste media (PWM) after maggot and chironomid larvae grown viz., 50%, 75% and 100% PWM and 100% Kosaric Medium (KM) as a control for a period of 14 days. Among the three different concentrations, 50% PWM showed significantly (p<0.05) higher growth than other concentrations of media except control media (100% KM) in respect to cell number, chlorophyll a, specific growth rate of cell and chlorophyll a and total biomass. The physico-chemical parameters of the culture media were found within the suitable range of S. platensis culture. Proximate composition analysis showed that the cultured S. platensis was rich in protein, lipid and other mineral contents. Protein percentage of S. platensis was significantly (p<0.05) higher in 50% PWM than others except control KM.5-day old fish (C. batrachus) fry were reared in aquaria by feeding those cultured live food organisms in ten treatments viz., T1, T2, T3, T4, T5, T6, T7, T8, T9 and T10 including a control fed on formulated diet (40% protein contained) for a period of five weeks in laboratory conditions. In respect of length and weight gain and specific growth rate (SGR, %/day) of reared fish were significantly (p<0.05) higher in T1 when fed on 75% maggot and 25% formulated feed than other treatments. The reared fish fry were found nutritionally rich. It was concluded that culture of live food organisms might be established in Bangladesh using poultry waste as an inexpensive media, which ultimately promote culture based aquaculture system and environment will be partially free from pollution.