Article

Histopathological changes in gills of the estuarine crab Chasmagnathus granulata (Crustacea-Decapoda) following acute exposure to ammonia

University of Buenos Aires, Buenos Aires, Buenos Aires F.D., Argentina
Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology (Impact Factor: 2.3). 02/2000; 125(2):157-64. DOI: 10.1016/S0742-8413(99)00093-6
Source: PubMed

ABSTRACT

Histopathological effects of ammonia on the gills of the estuarine crab Chasmagnathus granulata (Dana, 1851) were evaluated after acute exposure to ammonia concentrations around LC(50) value (17.85 Mm). Disruption of pilaster cells and a subsequent collapse of gill lamellae were the main effects observed. Epithelial necrosis and hyperplasia were also detected. Significant (P<0.05) increases in pCO(2) and lactate, and significant decreases of pO(2) were detected in the haemolymph of ammonia-exposed crabs. These changes suggest that the observed histopathological damage affected gas exchange, possibly leading to death.

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    • "Although total hemocyte count decreases in crustaceans exposed to stress conditions, circulating hemocytes are also affected by extrinsic factors such as temperature, oxygen levels and pH (Le Moullac and Haffner, 2000; Cheng and Chen, 2002). Besides changes in the gill structure and physiology (Rebelo et al., 2000; Romano and Zeng, 2007), exposure to high ammonia titers can induce alterations in cellular and humoral components of the crustacean immune system (Le Moullac and Haffner, 2000; Liu and Chen, 2004), the release of free oxygen radicals (Le Moullac and Haffner, 2000), hemocyte apoptosis and activation of antioxidant enzymes (Zhang et al., 2015). However, while alterations in hemocyte count in crustaceans exposed to elevated ammonia titers are highly speciesspecific , the mechanism leading to a decreased hemocyte count is not clear as yet (Cheng et al., 2003; Jiang et al., 2004; Liu and Chen, 2004; Hong et al., 2007; Verghese et al., 2007; Rodríguez-Ramos et al., 2008). "
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