Effect of vitamin B₁₂ on resilience to turbidity stress for Moina macrocopa

Abstract

Sediment transport associated with extreme rainfall has become an important issue for aquatic animals under conditions of ongoing climate change. In this study, effect of vitamin B₁₂, which is exclusively produced by bacteria in nature, were investigated for maintaining zooplankton fitness in changing environment. A series of experiments were conducted to explore possible damages caused by turbidity change and mitigation by vitamin B₁₂ on the fitness of Moina macrocopa. Test animals were exposed during their entire lifespan with different levels of turbidity (0, 15, 50, 100, and 600 NTU by adding kaolin clay) and fed by Chlorella vulgaris with various levels of supplemental vitamin B₁₂ (0, 5, 25 µg/l) and a commercial product which contained vitamin B₁₂ in the cell. M. macrocopa showed better performance when fed on Chlorella with vitamin B₁₂ compare to Chlorella without vitamin B₁₂ upon exposure to turbidity change. The absence of vitamin B₁₂ together with turbidity change exposure decreased lifespan, delayed the age of first reproduction, and decreased offspring number and size (P < 0.05). These results revealed that the resilience of M. macrocopa to turbidity change can be enhanced by the help of vitamin B₁₂ in media and/or foods.