Effects of silverside and sorghum meals on growth performance, proximate composition and histological features of Thinlip Grey Mullet (Liza ramada) fingerlings.

Abstract

Future aquaculture growing may be constrained by fishmeal availability, which is influenced by environmental factors (such as climate changes). As a result, finding cheap sources of carbohydrates or alternative animal protein has become essential for aquaculture production to be sustainable. A total of 1200 fingerlings of Mullet (L. ramada) were obtained from the private farm at Fayoum Governorate and transported to the National Institute of Oceanography and Fisheries (NIOF) to use the local ingredients from silverside and sorghum to replace imported fish meal and yellow corn in mullet diets. The experiment was applied using a completely randomized design. Fingerlings were distributed in twelve fiberglass tanks with a volume of 2 m3 with a stocking density of 100 fingerlings/ tank with an initial average weight of (3.8 ± 0.1g). Four experimental diets were used: Control (D0), which contains fish meal and yellow corn, the second, third, and fourth diets incorporated each silverside and sorghum meals to replace, 50, 75, and 100% (D50, D75 and D100) of fish meal and yellow corn. The results showed that D100 gave the best gain and growth performance, followed by D75 without a significant difference between them. However, less performance was obtained with D0 and D50. The proximate carcass composition and muscle fatty acids contents of fish were not significantly affected by the incorporation of silverside and sorghum meals in mullet diets. In the same trend, the intestinal villi from the experimental groups did not show any changes in the mucosal layer, immune cells, and lymphatic vessels between tested groups. The present results confirmed that the incorporation of 100% silverside and sorghum meals can be used in mullet diets to spare the expensive imported meals from fish meals and yellow corn.