Gross and histological signs of dietary deficiencies of biotin and pantothenic acid in lake trout, Salvelinus namaycush.

We describe the pathologic changes of single or simultaneous dietary deprivations of biotin (B) and pantothenic acid (PA) in lake trout, Salvelinus namaycush. A deficiency of PA produced gross signs of anorexia, inanition, emaciation, gill abnormalities and high mortality. In B-deficient fish, growth retardation reached statistically significant levels (P less than 0.05) after week 10, but gill and liver lesions were observed earlier. Anorexia and reduced weight gain were observed earlier in fish deprived of both nutrients than in those deficient in B alone. All B-deficient trout fed PA survived the study, and were less anorexic, anemic and emaciated than were those fed B without PA. Deposition of glycogen was greater in kidney tubules of B-deficient fish than in those lacking both vitamins. However, lesions interpreted to be mitochondrial conglutination and cellular necrosis of renal tubules and pancreatic acini were more exaggerated in fish fed neither nutrient than in those deprived of only one. Both vitamins are needed for energy transfer metabolism and their absence in metabolically active tissues causes lesions that resemble those reported for cellular anoxia.