The effects of densities and feed types on the production of Macrobrachium rosenbergii (de Man) in the rotational rice-prawn system.

摘要

Postlarvae (PL) of Macrobrachium rosenbergii (de Man 1879) were stocked at 1, 2, 3 and 4 PL m-2. Prawns were fed only pellets (P) and a combination of pellets and snail meat (PS) with three replications in 100 m2 plots in the rotational prawn-rice system. Water levels were 0.3-0.6 m in rice growing areas. The water temperatures at noon in the hot months were higher than the suitable range for prawns. The final mean weights of prawns in treatments 1, 2 and 3 PL m-2 were significantly higher than in treatment 4 PL m-2 (P<0.05). The yields from different density treatments ranged from 194+or-82 to 373+or-32 kg ha-1 and increased significantly with the increases in prawn densities (P<0.05). There was no significant difference between the two types of feed on production parameters (P>0.05). The total cost significantly increased at higher densities (P<0.05), but it was not different between feed types (P>0.05). Net profit and cost benefit ratio of treatment PS were significantly higher than in treatment P. In the present study, treatment 3 PL m-2 and treatment PS offered the optimal results..