Efeitos de espectros de luz no comportamento e desenvolvimento larval do camarão da Malásia, Macrobrachium rosenbergii

Abstract

In indoor cultivation systems, it is essential to provide elements that favor the development of aquaculture species. Given this, the light spectrum, can improve growth and increase survival in different species. Three experiments were carried out with the objective of investigating the effects of red, blue, green, white light and absence of light on larval development, ingestion of Artemia nauplii and light color preference in Macrobrachium rosenbergii larvae. The results of the present study demonstrate a significant influence (p<0.05) on larval development, productivity, survival and final biomass of M. rosenbergii larvae. In general, the inferior results were from the animals exposed to the dark regime and under the red light. M. rosenbergii larvae, at the end of the study, showed the highest larval stage index and larval condition index under the white light spectrum, followed by blue and green light. The reduction of the limpid content of the intestine (hepatopancreas condition), the condition of the intestine and the color of the body were the main parameters that conditioned the reduction of the ICL. In the study on Artemia nauplii ingestion, the lowest total consumption of nauplii was observed under the black regime (no light) (2,065 nauplii), and the highest total consumption was under white light (3,998 nauplii). According to the results, in stages II, III, X and XI the color of the environment did not influence the ingestion of Artemia nauplii (p>0.05), however, between larval stages IV to IX there was a significant variation in the number of nauplii consumed, in which the larvae consumed more nauplii being under the effect of white, blue and green lights, compared to red light and under the absence of light. Regarding color preference for M. rosenbergii larvae, it was verified that in stage VII the animals preferred to remain under white light, regardless of whether they remained in a group or alone. As development progressed (stage XI), the animals began to prefer blue light (p<0.05). In summary, the results suggest an interaction between light spectrum and life stage, demonstrating that different light environments can affect the behavior of M. rosenbergii larvae. Based on our results under laboratory conditions, it is suggested that white light is the most favorable for larviculture of M. rosenbergii and that the effect of light color is species-specific for all analyzed parameters.