Effects of Microalgae Chlorella vulgaris Density on the Larval Performances of Fresh Water Prawn Macrobrachium rosenbergii (De Man, 1879)

Abstract

Background: Microalgae have several potential applications in early stages especially in the hatchery phase of several fish, mollusc and crustacean species. The present study aimed to evaluate the effects of microalgae Chlorella vulgaris at different concentrations on larval performances of Macrobrachium rosenbergii. Methods: Freshly hatched larvae were reared until the metamorphosis of first post larval (PL) stage in plastic aquaria (5 liter, 12ppt and 12L:12D) with a density of 10 larvae/liter under five randomly arranged treatment groups in 3 replicates such as, 0×105 (T1, control) and four different concentrations of C. vulgaris 5×105 (T2), 10×105 (T3), 15×105 (T4) and 20×105 (T5) cells/ml. Larvae were fed Artemia (6 nauplii/ml) six times daily. Result: The results revealed that the addition of microalgae in rearing system significantly enhanced (P less than 0.05) the larval survival and developments than without microalgae. The highest larval survival and faster appearance of PL (in days) was observed in T3 group (60.83%, 24.67 days) followed by T4 (56.91%, 28.33 days) T2 (48.39%, 31.33 days) T5 (40.93%, 32.33 days) and T1 (30.65%, 39 days), respectively. Larvae reared at moderate concentrations of microalgae (T3 and T4) resulted in high dry weight that of extreme low (T2) or high (T5) concentrations of microalgae. This study identified the best concentration of Chlorella vulgaris for the rearing of M. rosenbergii larval and could be applicable for the mass larval production of this species commercially.