Higher final weight of fries of Oreochromis aureus was attained due to feeding on the tested coloured feeds rather than basal diet. Non-significant changes were reported for most of growth parameters for fries. However, they have significant reduction of specific growth rate (SGR) due to feeding on blue and yellow feeds. On the other hand, fingerlings fed with basal diet exhibited a better growth performance than those fed with different feed colours. Significant reduction in final weight (Wf), weight gain and average daily weight gain (ADG) of fingerlings fed brown feed colour were reported compared to control. Aspartate aminotranaminase (AST, E.C 2.6.1.1) and alanine aminotransaminase (ALT, E.C 2.6.1.2) activities were significantly reduced in fries fed with blue and brown feeds compared to control. Similarly, alkaline phosphatase (ALP, E.C.3.1.3.1) activity and albumin level were significantly reduced in case of fries fed with brown feed colour. For fingerlings, there were significant differences found among the experimental groups, in total protein, albumin, AST, ALT, and cholesterol. Glutathione (GSH) and water content were generally reduced in fingerlings fed with the examined tested coloured feeds. Blue and brown feed colours induced significant reduction in most of the tested biochemical parameters from those of the control. The present study suggests that using coloured feeds did not promote growth of Oreochromis aureus, both fries and fingerlings. Also, adverse biochemical changes for those fed with coloured feeds were reported. Therefore, ordinary basal diet is recommended.
Key words: Feed colours, Growth, Biochemical parameters, Fries, Fingerlings, Oreochromis aureus.
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