Culture of Zooplankton (Brachionus Calyciflorus, Moina Micrura and Daphnia Pulex) As Live Food Heterobranchus Bidorsalis Hatchlings

Abstract

Live food Zooplankton population density in different zones of Awuma River at Shabu were investigated and Brachionus calyciflorus, Moina micrura and Daphnia pulex screened from littoral zone of the River at Shabu before the onset of rainy season was isolated into mono specific culture in the laboratory. Cow dung, chicken droppings, groundnut cake, soyabean cake, rice bran and single super phosphate were combined in different proportions of three, four and five combinations of manure in solution (3CM1...4, 4CM1...4 and 5CM1...4.) in three replicates for culture period of 9, 11 and 12 days for each of the zooplankton respectively. Effects of concentration, combination of manures and duration of production of the zooplankton were investigated. Dissolved oxygen, (mg/L) temperature (0C), carbon dioxide (mg/L) and total alkalinity (mg/L) of the water used for the various treatments were monitored. Chlorella vulgaris was cultured using repeated subculture method. Effects of filtrate of the combined manure and C. vulgaris on population density of B. calyciflorus and M. micrura were determined. Influence of temperature on percentage fertilization, hatchability of Heterobranchus bidorsalis eggs and survival rate of hatchlings were investigated in Jos in a controlled temperature hatchery. The effects of Artemia shell free, live B. calyciflorus, D. pulex, M. micrura, and a combination of M. micrura & B. calyciflorus on percentage weight gain, total body length, condition factor and percentage survival rate were also determined. The fish eggs (500) were mixed with milt and spread on mosquito net kakaban in aquaria in 4 treatments (260C, 280C, 300C and 320C) in three replicates. The numbers of unfertilized eggs were counted after 6 hours from the time of mixing of the eggs with the milt. The kakabans were removed after the hatching and hatchlings were counted then and after 3days. Fry (50) of 3 day-old were placed in a 10 litre plastic bowl in five treatments of 3 replicates for 16 days. Initial average length (cm) and weight (g) of the fry were recorded. Littoral zone of Awuma River had the highest population density of live food micro organisms. The highest population density of cultured B. calyciflorus (245 individual/ml of water) and of D. pulex (26,303 individual/L of water) were observed on day 5 and day 9 respectively in treatment 5CM1at concentration 4.00ml/L of water while M. micrura highest population density (55,184 individual/L of water) was observed on day 9 in 5CM2 at concentration 4.00ml/L of water. Beyond day 7 and day 9, a declining population density was observed in B. calyciflorus, M. micrura/D. pulex respectively. Population density of B. calyciflorus fed on filtrates of the manure was significantly (p<0.05) higher than those fed with Chlorella vulgaris. Water temperature range of 28-30oC was found to be significantly best for percentage fertilization, hatchability of eggs and 28oC for survival rate of catfish hatchlings. Mixture of B. calyciflorus & M. micrura significantly influence the highest percentage weight gain, total body length, survival rate and condition factor of Heterobranchus bidorsalis fry. These findings are highly recommended for zooplankton and fry production.