Effects of salinity, photoperiod, and light spectrum on larval survival, growth, and related enzyme activities in the giant freshwater prawn, Macrobrachium rosenbergii

Little is known about the effects of environmental factors on the early life history stages of giant freshwater prawns (Macrobrachium rosenbergii). Here, we conducted three experiments to analyze the effects of salinity (10 parts per thousand, 13 parts per thousand, and 16 parts per thousand), photoperiod (light dark cycle = 0:24 h, 6:18 h, 12:12 h, 18:6 h, and 24:0 h), and light spectrum (red, yellow, white, green, and blue) on the growth performance and enzyme activity at the larval developmental stage. Our findings reveal that all three factors significantly influence the growth and metamorphosis of giant freshwater prawn larvae, and the best performances were obtained at a salinity of 13 parts per thousand, with a photoperiod of 24 h light:0 h dark, and under green or white light. Red light was found to disadvantage the larval development of this species. These three environmental factors influenced the activity of four enzymes (superoxide dismutase, catalase, alkaline phosphatase, and lysozyme) to varying degrees, and the activities of all these enzymes decreased with a longer light period. The present study of these three environmental factors is an extensive resource for the future culture development of this species.

Automated summary

The study found that salinity, photoperiod, and light spectrum significantly influence the growth and metamorphosis of giant freshwater prawn larvae, with red light being disadvantageous for larval development while green and white light produce the best results. The activities of four enzymes were also affected by these environmental factors, decreasing with longer light periods. This research provides valuable insights for the future aquaculture development of this species.