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Aquaculture Feed and Fertilizer Resources Information System
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Deficiency diseases
A dietary deficiency in pyridoxine results in growth retardation, high mortality, poor food conversion, hyper-irritability coupled with erratic swimming behaviour, and degenerative changes in peripheral nerves (Kissil et al., 1981). Morris, Davies and Lowe (1995) observed that a dietary deficiency in thiamine, riboflavin, pyridoxine, niacin and pantothenic acid led to reduced feed intake, anorexia, anaemia and histological changes in the liver, besides skin colour changes, poor growth and increased mortalities. A lack of vitamin C leads to extensive tubular damage, glomerulonephritis and inflammatory response of the haemopoetic tissue leading to granuloma, etc. (Alexis, Karanikolas and Richards, 1997), as well as decreased resistance to stress (Henrique et al., 1998). Decreased immune response is observed under conditions of α-tocopherol or polyunsaturated fatty acid deficiencies (Montero et al., 1998). Such nutritional deficiency signs are, however, not commonly observed under current farming conditions, since most feeds are adequately supplied with vitamins, minerals and trace elements. |
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