Effects of four different doses of organic manures in the production of Ceriodaphnia cornuta

Mass culture of Ceriodaphnia cornuta was done by using a mixture of organic manures: cattle manure:poultry droppings:mustard oil cake (1:1:1) at four different doses: 0.263 kg/m3 (first dose), 0.526 kg/m3 (second dose), 1.052 kg/m3 (third dose) and 2.104 kg/m3 (fourth dose). The peak of C. cornuta was found on 10th day of inoculum in first two doses and on 14th and 18th day in third and fourth doses, respectively. Among these four doses, significantly (P < 0.01) higher numbers of organisms (1930/l) were found in the fourth dose followed by third (1470/l), second (1017/l) and first (733/l) doses, respectively. The number of organisms decreased faster in two lower doses than higher doses. pH ranged from 7.20 to 8.09, 7.46 to 8.01, 7.55 to 7.89 and 7.61 to 8.03 in first, second, third and fourth doses, respectively. Dissolved oxygen showed inverse relationship with the dose of manures applied and direct relationship with number of organisms. This study showed that 3.28–4.63 mg/l dissolved oxygen was optimum to obtain the bloom of C. cornuta under the present manure schedule. Maximum number of organism was found when unionized ammonia and phosphate levels ranged between 0.65–0.85 mg/l and 0.42–0.98 mg/l, respectively. The fourth dose of organic manure is optimum for the culture of C. cornuta in outdoor condition and the bloom of the live food can be obtained within 18 days of inoculum.