Читать книгу Clinical Guide to Fish Medicine - Группа авторов - Страница 46

The liver is the primary lipid storage organ in elasmobranchs, which helps maintain neutral buoyancy. A large volume of lipid must be stored in the liver, and the size and density are critical in maintaining position in the water column. As the primary energy storage organ, the liver is also an indicator of general health and caloric intake, although size may fluctuate with the reproductive cycle or age (Hamlett 1999; Hussey et al. 2009). A hepatosomatic index (HSI), the ratio of liver weight to body weight, has been identified for many species as a “fitness” indicator (Sherman and Gilliam 1996; Hoffmayer et al. 2006). Grossly the liver should be tan‐colored, fill a large percentage of the ventral coelom (Figure A1.19), and float in formalin; if it does not, there are inadequate lipid reserves. Normal elasmobranch livers may easily be misinterpreted as hepatic lipidosis on histology. The gallbladder is dynamic and appears to increase in size with inappetence.

Figure A1.19 Gross appearance of a normal liver (a) and a small liver (b) at necropsy of a southern stingray (Hypanus americanus). The open coelom shows the liver (Lv), spleen (Sp), valvular intestine (VI), ovary (Ov), and epigonal organ (Ep).