الفهرس | Only 14 pages are availabe for public view |
Abstract The experimental system consisted of 27 glass aquaria (60×35×40cm) each aquarium was continuously supplied with a compressed air from an electric compressor. Dechlorinated tap water was used to change one third of the water in each aquarium every day. Water was aerated before be used for about 24 hours to remove chlorine. A group of Nile tilapia O. niloticus with Average initial body weigh of (20-25g) for three density 2, 3 and 4 g fish / liter. The fish were fed during the acclimatization period on artificial basal diet at a rate 3% of the body weight daily, at 2 times daily. The experimental treatments were tested in three aquaria for each. A basal diet (28% crude protein) was formulated from the memorial ingredients (fish meal, soy bean meal, yellow corn, wheat bran, sun flower oil, vit. & min. mixture and betaine).In the present work, feeding O. niloticus fish with diet containing different levels of betaine (0.0, 0.5 and 1.0%) and stoked in the three densities (2, 3 and 4 g fish / liter) led to some results from the foregoing results it could be concluded that the useful addition of 0.5% and/or 1.0% of betaine in the diets of Nile tilapia O. niloticus to increase or enhance the fish growth and fish production. Also, this material (betaine) is useful to alleviate from the stress of different densities in fish ponds. |