Quantification of liver lipid deposition and melano-macrophages in lesser guitarfish Zapteryx brevirostris submitted to different feeding cycles

Abstract

The objective of this study was to evaluate and quantify the fat storage in the liver of lesser guitarfish Zapteryx brevirostris submitted to different periods of restriction and refeeding. In a water recirculation system, 21 animals were divided into three groups: control (n=7), fed every day; W1 (n=7), with one week of restriction and two of refeeding and W2 (n=7), with two weeks of restriction and two of refeeding. After 76 days, the animals were euthanized and liver samples were collected, paraffin embedded, stained with PAS and evaluated with stereological procedures and histopatological changes were recorded. The area occupied by fat in the liver of control group was higher than that found in groups W1 and W2 (p<0.001). Melano-macrophage center areas and diameters have risen with increased fasting period while there were swollen and necrotic hepatocytes. These results pointed to physiological adaptations and liver lesions caused by free radicals during fasting periods. Similarly to teleost fish, there was a consumption of lipid reserves while enhancing the gluconeogenesis during fasting.