Abstract
A total of seven experiments were conducted to produce house fly(Lucilia sericata) larvae (maggot) and spirulina (Spirulina platensis), and to evaluate their efficiency as ingredients replacing fish meal (FM) (sole source of good quality animal protein) in diets of stinging catfish (SCF) (Heteropneustes fossilis) post-larvae (PL). The cassava tuber powder (CTP) as a rich source of carbohydrate (starch) was used in diets as replacer of wheat flour. The objective was to use maggot meal (MM) and spirulina meal (SM) as rich sources of good quality protein for reduction of high pressure on FM and as alternate sources of FM in the country. Similarly CTP was used as an alternate source and to reduce use of wheat flour as source of carbohydrate (starch). The maggot was produced in higher amount (1050 ± 40 g live weight) in 6.0 kg poultry waste than 9.0 kg followed by 3.0 kg nearby a poultry farm within three days through Experiment 4.1. It was cleaned taking in mosquito net through washing, collected, dried, ground, sieved and the meal was kept in plastic packets for use in diets and chemical analysis. Some small maggot were sorted and small ones were kept in frozen condition for future use as feed for SCF PL. The small frozen maggot was use to feed SCF PL in four different proportion and a control diet where diet 3 (60% frozen larvae, 33% crude protein) gave better growth performances of SCF fry than other diets. The SCF PL fed diet 3 contained 25% FM and 75% MM (30% crude protein) gave significantly (p < 0.05) better growth performances than those fed other diets through Experiment 4.3. The SCF PL fed diet 3 prepared with 20% CTP (crude protein 30%) gave better growth performances than those fed other diets made with 25, 15 and 10% CTP through Experiment 4.4. Better growth and production of spirulina was (almost 1.0g/L on dry weight basis) found in supernatant of digested 4.0g/L poultry waste than other concentrations through Experiment 4.5. It was collected, dried and made meal for use in diets and chemical analysis. Spirulina meal was used to prepare four diets with different inclusion levels of FM with SM where SCF PL fed diet 3 (CP 7.50% of FM & CP 22.50% of SM), diet 2 (CP 15% of FM & CP 15% of SM), diet 4 (CP 100% SM) and diet 1 (CP 22.50% of FM & CP 7.50% of SM) gave better growth performances than those fed control diet through Experiment 4.6. From the results of Experiments 4.3, 4.4, 4.5 and 4.6, the final experiment (4.7) was conducted where SCF PL fed diet 2 (7.50% CP of FM, 7.50% CP of MM & 15% CP of SM) and diet 1 (7.50% CP of FM, 15% CP of MM & 7.50% CP of SM) gave significantly (p < 0.05) better growth performances than those fed control diet 5 (T5). The overall survival rates of the experiments were ranged from 76 to 92%. It was concluded that due to high growth performances of stinging catfish post- larvae fed diets prepared with cheap ingredients as MM and SM replacing FM, and CTP replacing wheat flour. Though poultry waste and other agro-industrial wastes are easily available and cassava will be produced in fallow land specially in river side, therefore the protein rich ingredients as maggot and spirulina and carbohydrate rich ingredient as cassava tuber produced in large amount as well as industrial scale with low expenditure in the country as well as other countries. These ingredients will reduce the cost for production of feed for fishes and other farm animals, and ultimately reduce the high demand of fish meal and cassava tuber powder instead of wheat flour. The fish and other animal farmers will be benefited using the feed prepared with these low cost effective ingredients. Nation will be benefited in at least two ways - 1) food and feed ingredients will be produced, and 2) pollution will be partially reduced.