Histological effects of Cu²⁺ to white shrimp Litopenaeus vannamei (Crustacea: Decapoda) juveniles at low salinities

Juveniles of the white shrimpLitopenaeus vannamei were exposed during 25 days to the Cu²⁺ concentration commonly used in Mexican shrimp farms, at salinities of 1, 5, and 10 psu, in order to observe possible histological alterations to the antennal glands, midgut, gills and hepatopancreas. Survival was 100% in controls and treatments, and no histopathologies were observed in gills, midgut and antennal glands. Sloughing of epithelial cells (< 75%), infiltration of hemocytes (< 75%) and reduction in R and B cells (100%) were observed after 10 days in the hepatopancreas of shrimps exposed to Cu²⁺ at the lowest salinity and, to a lower degree, at salinities of 5 and 10 psu. This should be taken into consideration to establish criteria of acceptable water quality for inland aquaculture, because the interaction metal-salinity may induce adverse shrimp responses.