Determine optimal diet for rearing black tilapia (Oreochromis niloticus) in Bafgh brackish water

Tilapia is one of African native fishes has been introduced to many thermal and temperate regions in the world for second part of twentieth century. First, intensive culture system dependes on complete and wide information in nutrition requirements, specially protein as most expensive nutrient; second, the importance of tilapia in future of Iran; and third, lipid as first non-protein energy source that is so influent and it’s unsufficient values affect negatively on growth and protein requirement, make us to investigating the protein and lipid requirement of Nile tilapia Oreochromis niloticus to achive a convience diet causing most economical interest by maximum growth and minimum feed conversion ratio. This experiment performed in Bafgh Inland Saline Water Fish Research Station. It was planned in four protein (15, 22, 29 and 36%) and three lipid (5, 9 and 13%) levels in factorial system. Thirty six 300 l tanks with 150 l water and 3 l/min water flow used for 12 treatments with triplicates. 15 male Nile tilapia fingerlings (13.94±0.88 g) kept in every tank and fed near satiation during 8 weeks experiment. There was any significant different in survival in all treatments. Growth performance (WG & SGR), feed and protein efficiency (FCR & C and PER & PCE respectively) improved with increasing proein level until 29%, however, significant positive effect was not observed by lipid increasing. Then, best economical protein and lipid level for convinienc growth performance and protein and lipid efficiency is 29 and 5% respectively. In 5% lipid, maximum growth and protein efficiency appears between 33.9 to 35.3% protein according to the mathematical method (polynomiyal curve)

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

Artificial propagation and Culture of Rutilus frisii kutum of Autumn form for restocking

The Kutum, Rutilus frisii kutum, is one of the most important bony fishes in Iranian coastal of Caspian Sea. Its harvest range is between 9000-10000 tons in a year, nearly 60% of the income of Bony fish fishery produced by kutum fishery. The stock of this species reduced drastically in 1982 and the catch slumped to the less than 250 tons in a year. Kutum spawning grounds deterioration, illegal catch, and lack of restocking program were the main cause of the decline. This Spices in nature comprised by two distinct form, autumn and spring form. It is worth to be mentioned, by the effect of Caspian Sea Bony fishes Research Center s experts in 1983, artificial spawning and releasing the fries to the sea were commenced and the catch steadily improved. But all activities concerning restocking of kutum concentrated in spring form, as at present about 260 million its fries are released into sea for restocking by Iranian Fisheries Organization, but for above reasons and lack of restocking program, the populations of autumn form gravely shrinked and neared to be extinct. Therefore, to enhance the biodiversity and boost fishers livelihood of kutum in Caspian Sea this project implemented by cooperation of Iranian Fisheries Organization (IFRO) and Caspian Environment Program (CEP) in Aquaculture Institute (Inland Waters). In this project, brooders caught from Anzali lagoon and maintained in two different condition, include of floating cages in Anzali lagoon and earthen ponds in Sefidrud Fisheries Research Station. The results showed that there weren’t significant differences between two maintenance statuses in maturation period and other reproductive characteristics of brooders. The ratio of male to female was 1 to 1.4. Minimum and maximum weight measured 1450 to 3100 g (with average of 1850 g) in female and 670 to 1900 g (with average of 1165 g) in male, respectively. The first natural spawning of brooders occurred in the end of January in temperature of 8 till 10 °C in concrete ponds. Also, some of maintained brooders in earthen ponds spawned in February. The average number of absolute, function and relative fecundity determined 88565 16809, 73805 14008 and 48670 12056, respectively. For artificial spawning, male and female brooders injected by pituitary gland with dose of 2-3 and 4-5 mg/kg body weight, respectively. Approximately, 10 and 8 present of female were over-ripe and immature in March (artificial spawning time), respectively. More than 59 % of injected female brooders induced to spawning in first stage after 10-12 hours and 13 % of them in twice stage and 7-8 hours after first stage. And also, 27.6% of females didn’t positive response to injection. Dry method used for eggs fecundity and incubation period lasted 7- 10 days in 14-16 °C. In totally, eggs fertilization were more than 95% and the average of eggs fertilization percent in throughout of period measured more than 92.7 6 %. Eyed eggs appearance occurred 3 days after fecundity and its mean was 92.7 15.1%. Larvae after yolk sac absorption feed with dry milk for 4-5 days and then introduced into fertilized earthen ponds (500 m2 and equipped to aerators) in intensive condition and fed with micro pellet food for 3-4 month. In finally, more than 1.8 million fries of 1-2 g and some more than 5 g produced and released into Anzali lagoon to its restocking for first time. It is expected that continuing of restocking process of autumn form kutum by Iranian Fisheries Organization eventuate to population increasing of this form in Caspian Sea in future

Responsible aquaculture: feeding management and preparation of guidelines

In this study, data were gathered from library research, discussing with feed and feeding experts in warm and cold water fish farms and also from research project implemented by executer. Standardization on selection of materials and ingredients percentage in order to prepare dry pellet feed for these two kind of cultured fishes emphasized on proximate composition energy, carbohydrate, protein with amino acids profile, lipid with fatty acid profile, minerals and vitamins and also feeding frequency, kind of feed pellet manufacture were codified environmental friendly, according to responsible aquaculture. On the other hand, feed color, taste, smell, their attraction and the best physico-chemical condition for storing of in order to get optimum result of responsible aquaculture were recorded