Effects of Diatoms Amphora coffeaeformis on growth parameters, non specific immunity and protection of the Nile tilapia (Oreochromis niloticus) to Aeromonas hydrophila infection

F. Ayoub, Hala; F. Abdelghany, Mohamed; B. El-Sayed, Abo El-Khair

Effects of Diatoms Amphora coffeaeformis on growth parameters, non specific immunity and protection of the Nile tilapia (Oreochromis niloticus) to Aeromonas hydrophila infection

Document Type : Original Article

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Abstract

Eight weeks feeding trial was carried out to assess the growth promoting and the immune-stimulatory effects of the supplementation of Amphora coffeaeformis (A. coffeaeformis) in the Nile tilapia diets and its resistance to bacterial infections. Fish were fed on diet containing 0, 10, 20 and 30 g of A. coffeaeformis per kg . Growth performance parameters and body composition of experimental fish were evaluated. Serum protein profile (albumin, globulin, total protein and A/G ratio), serum liver function enzymes, and serum lysozyme were assessed. Therefore, fish in all the experimental groups were challenged with pathogenic Aeromonas hydrophila following the feeding experiment. The results showed that the growth-promoting influence of A. coffeaeformis was observed on Nile tilapia performance, the optimum growth and feed utilization were obtained at fish maintained on 10g A. coffeaeformis kg^-1 diet. A. coffeaeformis supplementation improved the protein and lipid contents in fish bodies without significant differences among them, especially when fed 20 or 30 g per kg, while no significant differences in the moisture and ash contents were observed among different treatments. As well, the physiological parameters (serum protein profile and serum lysozyme) were improved when fish were fed on A. coffeaeformis enriched diet. Besides, lysozyme activity was giving good results in 10, 20 and 30 g per kg. Fish mortality after challenged against A. hydrophila decreased with increasing A. coffeaeformis level in fish diets. These results indicated that A. coffeaeformis supplement is promising as an alternative method to antibiotics for disease prevention in Nile tilapia culture, and the optimum level of A. coffeaeformis in the fish diet should be ranged between 10 to 20 g kg^-1 diet.

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