And possibly cause liver damage, as fish can't process it properly: Metabolic and histological studies on the effect of garlic administration on the carnivorous fish Chrysichthys auratus Mohamed B. Al-Salahy, Abd Allah B. Mahmoud Abstract Chrysichthys auratus fish were orally administered with doses of garlic (Allium sativum) juice equivalent to 2g per kg body wt, as a single dose or the same dose every 48h for 5 and 11 days. The results showed a hypoglycaemia, hypolipidaemia, hypocholesterolaemia, hypotriglyceridaemia and drop in serum TFAA as well as promotion of lipogenesis and glycogenesis in white muscle in response to repeated doses of garlic. Such results may correlate with elevation of insulin release in the fish following garlic administration. Histological and biochemical studies confirmed liver glycogen depletion and liver histopathological changes including vacuolation, hypertrophy and degeneration of some hepatocytes, and dilatation and congestion of some blood vessels. Histopathological changes of the kidney were vacuolation and rupture of some renal tubules, and degeneration of the parietal cells of some Malpighian corpuscles. Garlic decreased the amount of collagenous fibres in both liver and kidney, and reduced carbohydrate content in the kidney. In spite of some cell degeneration in the liver and renal tubules, serum AST and ALT did not show any significant changes, while serum ALP was decreased. Generally, it could be concluded that garlic strongly affected carbohydrate metabolism in Chrysichthys auratus. Garlic may improve carbohydrate metabolism, probably lowering the dietary protein costs of the fish; the damage of garlic on both liver and kidney in this work may be attributed to the relative high dose of garlic used. Some physiological studies on the effect of onion and garlic juices on the fish, Clarias lazera M.B. Al-Salahy Abstract Fish, Clarias Lazera were orally administered onion (Allium cepa) or garlic (Allium sativum) juices. Contents of glucose, free amino acids, total lipids, triglycerides, cholesterol, albumin, total protein, urea, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum as well as glycogen, free amino acids, total lipids, triglycerides and cholesterol contents in liver, white and red muscle were determined 5 h and 24 h after a single dose or after repeated doses (1 dose every 24 h for 5 days). Both onion and garlic treatments caused a temporary hypoglycemia as well as liver glycogen muscle depletion accompanied with a significant elevation in white muscle glycogen suggesting that dietary onion or garlic may enhance the process of glycogenesis in white muscle. Onion feeding caused hypolipidemia accompanied with significant decreases in liver content of total lipids in response to the repeated doses for 5 days and a severe rise in the lipid content of red muscle at all periods. Such results suggest that dietary onion may enhance the process of lipogenesis in red muscle of Clarias lazera. Probably, the main precursor of such lipogenesis in the red muscle was the serum fatty acids. Moreover, dietary onion led to hypocholesterolemia accompanied with a significant rise in cholesterol level of both liver and red muscle. On the other hand, dietary garlic significantly decreased serum free amino acids after 5 h and 5 days. Furthermore, significant elevations of liver free amino acids were dedected in the onion-treated fish group (24 h and 5 days) and in the garlic-treated fish group (5 h), probably due to oxidation of thiol components (sulfur attached to the proteins). This result was accompanied with either a marked increase in white muscle free amino acids at all periods of garlic fish group, or a noticeable drop in the onion group (repeated doses). Also, dietary onion and garlic treatment led to an elevation in hepatic ureagenesis in spite of the unchanged serum urea level. Significant decreases of both serum AST and ALT in garlic groups (all periods) and in onion groups (repeated doses) were observed. In liver, AST and ALT showed temporary rises after onion or garlic supplementation. In general, it could be concluded that both dietary onion and garlic have a transitory hypoglycemic action as well as a promoting effect on the process of glycogenesis in white muscle whereas dietary onion promotes lipogenesis in red muscle of fish. Also, dietary garlic may enhance the white muscle uptake of free amino acids which, in turn, may promote protein synthesis.