Adaptation, growth and survival of tilapia (Oreochromis niloticus) in Bafgh brackish water

An experiment was conducted to evaluate the possibility of adaptation, growth and survival of Nile tilapia (Oreochromis niloticus) with 0.3g initial weight and red tilapia (Oreochromis sp.) with 0.7g initial weight in underground brackish water. Fry of Nile tilapia and red tilapia imported from Indonesia and after passing larviculture (25g) were examined separately in fiber glass tank by two replicate. Fish were fed at a restricted feeding program according to standard table during the light period. The results showed that some growth factors such as final weight, final length, daily growth rate, specific growth rate and weight gain in Nile tilapia were slightly higher than red tilapia but other factors such as survival and feed conversion rate in red tilapia were slightly higher than Nile tilapia. There were no significantly differences at 99% level among these factors. Length-weight relationship equation was w = 0.012×TL3.189 in Nile tilapia and w = 0.014×TL3.119 in red tilapia (r2 = 0.99), b value were 3.189 and 3.119 respectively in Nile and red tilapia representing isometric growth. According to the reliable growth and high survival rate (98%), it seems that both Nile and red tilapia could be good candidates for rearing in brackish water condition

Improvement of black tilapia (Oreochromis niloticus) diets with replacement of low-cost, native materials

Fish meal production has been fixed in the world because of a limitation in fish stocks. On the other hand, demand of fish meal is growing daily and consequent the cost, too. Therefore, attention to the other protein sources is nessesary. Some plant protein sources, especially oilseeds, have valuable potentials for replacing fish meal because of relative high production in the world and Iran and low cost. According to existing information and availability, cottonseed meal and canola meal were selected as oilseeds; and Azolla was considered whether to be controlled in north provinces of Iran as weed. Growth indices (WG and SGR), food (FCR) and protein efficiency (PER and PCE) of fingerling Nile tilapia Oreochromis niloticus were evaluated in 3 synchronous examinations with 12 treatments and 36 replications. Groups of control, canola meal (at rates of 25, 50, 75 and 100%), cottonseed meal (at rates of 15, 25, 35 and 45%), as the replacements of expensive protein sources (fish meal and soybean meal), and azolla (at rates of 13, 21 and 29% of diet) were studied. Growth indices, total food intake and protein intake of control group were higher than all diets contained plant protein sources. They decreased with plant protein increasing in every grous, separagely (p0.05) between control and canola meal (at rates of 25 and 50%), cottonseed meal (at rates of 15, 25 and 35%) and azolla (at rates of 13 and 21%). All plant protein ingredients were unpalatable, and consequent total food intake, protein consumption and growth decreased. It will be expected that Canola meal and cottonseed meal replace expensive protein sources at the rates of 50 and 35% respectively, and azolla use at the rate of 21% in diets If the problem in palatability solves