ENHANCED PYRIDOXINE SUPPLEMENTATION OF DIETS FOR GILTHEAD SEABREAM (SPARUS-AURATA L)

Using a high protein diet (483 g/kg), two trials were carried out to a ssess any potential benefit which may result from tire supplementation of diets for fingerling and grower class gilthead seabream with pyrid oxine at levels which were below, matched and far exceeded the minimum dietary requirement. At the level of supplementation below the minima l requirement (lowest level) the responses from the practical diet alm ost matched the responses from the diet containing an amount of pyrido xine corresponding to the published minimum requirement for the specie s and no significant improvement in performance was recorded in respon se to increasing supplement level. However, despite the absence of a m arked effect on overall performance, a small potential for increased a ctivity of alanine aminotransferase was recorded amongst grower class fish given diets containing the lowest supplement. The proximate compo sition of the grower class fish was unaffected by the level of pyridox ine supplementation though marginal increases in tile lipid content of the fingerlings were observed. At the haematological level, haematocr it, total haemoglobin and the plasma concentrations of glucose and pro tein were also unaffected. However, on the application of an acute str essor (repeated netting), significant alterations in haematocrit and p lasma glucose concentration reflecting dietary pyridoxine supplement w ere recorded.