Effect of feeding diets containing ethanol extract of algea, Sargassum angustifolium and Laurencia snyderia on growth, survival rate and skin pigmentation in Macro (Labidochromis caeruleus)

Brown algae (Sargassum angustifolium) and red algae (Laurencia snyderia) are important seaweeds in Persian Gulf that are great sources of protein, vitamins, minerals and pigments. Most important pigments are carotenoids that found in marine algae. To evaluate the effectiveness of marine algae on growth and coloration of ornamental fish, 210 fish (6.5±0.65g) were randomly divided into seven groups (each group contains 30 pieces of fish) and were conserved and fed for 60 days for studying. Control group received only the commercial diet (Biomar) wet with olive oil, other groups, were fed with ethanolic extract of sargassum and laurensia containing 5, 10 and 15 g/kg dry matter for two months. Growth factors (specific growth rate, feed conversion ratio, protein efficiency rate and condition factor) measured on days 0, 30 and 60 respectively. The results showed that the groups fed with algae, did not show significant changes in growth factors. In order to estimate colors in fish in different groups, imaging parameters, L*, a*, *b, Hue and Chroma in three different region were studied. The results showed that the yellow color and clarity and color intensity in all treatments which fed algae were significantly higher than the control group. The results showed that the measurement of carotenoids in the skin of fish fed with algae, laurensia, were significantly higher than control group. In the groups that fed sargassum, only the rate of 15 g/kg diet caused a significant increase the amount of pigment in the skin.