Effects of salinity, temperature, feed type and feed concentration on the reproductive rate of Brachionus angularis

Abstract

The impact of salinity, temperature, feed type and feed concentration on reproductive rate ‘r’ of Brachionus angularis were examined in the present study. Three salinity levels (0.5%, 5.0% and 10.0%), three temperature regimes (25±1 o C, 29±1 o C and 35±1 o C) and four microalgal diets, Chlorella ellipsoidea, Ankistrodesmus convolutes, Scenedesmus protuberans and Chlorococcum infusorium at a concentration of 1x 10 6 , 2x 10 6 , 3x 10 6 , 4x 10 6 , 6x 10 6 , 8x 10 6 , 10x 10 6 and 12x 10 6 were tested in the experiment. The findings showed that all these parameters have significant influence on reproductive potential of B. angularis. The optimum salinity and temperature required for highest ‘r’ were 0.5% and 28.0 o C, respectively. The intrinsic rate of reproduction ‘r’ of B. angularis for the best salinity x feed concentration with C. ellipsoidea (4x10 6 cells mL -1 ), A. convolutus (3 x 10 6 cells mL -1 ), S. protuberans (1 x 106 cells mL-1), and C. infusorium (4x106 cells mL-1) at the optimal temperature were 1.74, 1.57, 0.92 and 1.56. Based on the study, the maximum reproductive potential of B. angularis can be achieved by feeding with C. ellipsoidea at a salinity and temperature of 0.5% and 29 ± 1 o C, respectively, which is useful for larviculture of fishes.