Publications by authors named "Juan C Bautista-Covarrubias"

Cadmium (Cd2+) and copper (Cu2+) are considered immunotoxic metals and their presence in combination in the aquatic environment may cause effects on shrimp species as Litopenaeus vannamei. Thus, this research evaluates the combined effects of Cd2+ and Cu2+ on shrimp inoculated with Vibrio harveyi bacteria. The experiments were performed at 96-h of exposure to sublethal concentrations of both metals.

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The objective of this review is to synthetize knowledge of the relationship between metals and oxidative stress in aquatic crustaceans (mainly shrimp and crabs) to analyze antioxidant responses when organisms are exposed to metals because the direct metal binding to the active site of enzymes inactivates most of the antioxidant systems. This study reviewed over 150 works, which evidenced that: (i) antioxidant defense strategies used by aquatic decapod crustaceans vary among species; (ii) antioxidant enzymes could be induced or inhibited by metals depending on species, concentration, and exposure time; and (iii) some antioxidant enzymes, as superoxide dismutase increase their activity in low metal levels and time exposures, but their activities are inhibited with higher metal concentrations and exposure time.

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Moon phases influence the molting process of shrimp, which affect other physiological processes as immune response. This study analyzed some parameters of immune response: total hemocytes counts (THC), hemolymph clotting time and superoxide anion (O) production, total protein concentration, superoxide dismutase activity, and the presence of Vibrio spp. in Litopenaeus vannamei at different moon phases.

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White shrimp, Litopenaeus vannamei, subadults were exposed to four dilutions of the 96 h cadmium LC50 reported for postlarvae (PL12) of this species, and the effects were evaluated after 5, 48, and 96 h of exposure. While treatments did not affect survival and hemolymph clotting time increased with time, but not as a response to Cd exposure, the intensity of other responses was related to concentration, to time of exposure, and to their interaction. Hemocyanin decreased with time in all metal concentrations but increased in the control treatment, and an almost similar trend was observed with hemocyte numbers.

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