Hormonal sex reversal of rainbow trout (Oncorhynchus mykiss) by ethynylestradiol-17α (EE2)

Rainbow trout (Oncorhynchus mykiss) females grow larger and mature later than males, making all-female stocks economically advantageous. The objective of this research was to develop methods for the production of monosex populations of trout through the use of sex steroids. The synthetic estrogen ethynylestradiol-17α (EE2) was administered in single period-immersion treatment of 400 µg/l for 1, 2, 4 and 8 h to groups of newly-hatched sac fries of rainbow trout and in a 30 day dietary treatment of 5, 10, 15 and 20 mg/kgf of newly swum up fries. 73.4 And 94.5% females were obtained with 1 and 2-h single-immersion of EE2 respectively (38% female in control). However, higher doses progressively reduced the survival drastically. Sex ratios of dietary treatment of fry were 60, 57.4, 78 and 94% females respectively. Treatments also resulted in a slight increase of both weight and length. This increase was related to the method of hormonal exposure (dietary > immersion), but not dosage-dependent for utilized hormone. This demonstrates that the direct feminization of rainbow trout can be achieved and resulted in sex reversal ratio effectively but not decreased the growth, as observed in hormonal sex reversed females, and it would be a noticeable approach to the direct feminization of trout

Rearing of Indian craps fries to 1g weight in earthen ponds

30000 juvenile Indian majour carps (Labeo Rohita,Cirhinus merigala, Catla catla) imported (2007 and 2008) and transferred to the earthen ponds in Astaneh Fisheries Research Station (Gilan) and Sheiban Resaerch center (Khozestan), In order to assess the viability of rearing fry up to 1 gram fingerlings under the climatic condition of north and south part of Iran . Growth parameters from the larval stage to 1 g were studied also. The fry with 300 mg weight, were released in to 3ponds.specimens were separated to tree experimental categories. fishes were fed with artificial food and also with the natural products of the ponds which were enriched with organic fertilizers, after being equally stocked in the ponds .During the experiment, oxygen level ,PH, turbidity, and temperature were measured . Monthly fry samples were taken, for weight and length biometrical analysis and also determination of the weight gain percentage, average daily growth rate, specific growth rate. Results have indicated adaptations and considerable growth in this species, with an increase from the initial weight of 300 mg to an average of 13.5±1.6 mg in 50 days period until the end of November for fingerlings.Catla was gain 1 g. during 15 day while Roho and Merigal were gain 1 g. during 14 and 10 days respectively. Results revealed that the Indian majour carps compatibility with the condition in Gilan province was succesfull and the combination of species and optimization of their compatibility specialy in other provinces like Sistan and Baluchestan were remind for futhre studies

Production of monosex female population of rainbow trout by use of 17-B estradiol as direct method

In many species of finfish, females exhibit higher growth rates than males and achieve larger sizes. In addition, in some species, males mature before reaching marketable size. Therefore, there is great interest from the fish farmers to produce all-female stocks. In this project tried to reversing the sex of rainbow trout larvae by 17 estradiol and direct method, further more finding the optimum dose of this natural estrogen for endocrine sex reversion of Rainbow trout (O. mykiss). Four experimental treatments were designed with doses of 10, 20, 30 and 40 mg/kgf. Trout which treated with 40 mg/kgf yielded 96% female and greatest growth

A study on methanol herbal plant extract of Echinacea (Echinacea purpurea) on immunity level of Mugil cephalus

Medicinal plants have been used in oriental medicine for centuries. Echinacea purpurea (Asteraceae), also known as the purple coneflower, is an herbal medicine with positive effects on various immune parameters that has been used customarily as a treatment for the common cold, coughs, bronchitis, upper respiratory infections, and some inflammatory conditions. The aim of this study was to investigate the effect of Echinacea purpurea (EP) extract on a non-specific immunity of Mugil cephalus. Three hundred and sixty Gray mullet larvae with average weight of 0.75 ± 0.02 g and an average length of 4.40 ±0.81cm collected from Ramin port where is located at 5 km far from the Chabahar and finally transferred to lab of trial in Offshore Research Center. This research was designed based on 4 treatment, Each with 3 replicates. The major factors examined containing growth factors mainly consists of average weight, average daily gain, protein efficiency rate, protein productive rate, hematological and biochemical factors including globin, albumin, total protein, lysozyme, ultimately, immunological factors, and respiratory burst and phagocytosis percent. In general, the results of this study showed that the addition of 100 and 200 mg of EP extract per kg of diet led to a significant increase in growth parameters (final weight, food intake, daily growth rate and efficiency of protein), hematology (RBC, WBC, Hb, Hct) and biochemical factors (total protein, albumin, globulin) in gray mullet were compared to control. The highest lysozyme activity, immunoglobulin, phagocytosis and respiratory burst was observed in treatment containing 200 mg EP extract per kg food. Treatment containing 200 mg EP extract per kg food showed a minimal mortality after challenge with bacteria photobacterium damselae compared to the control treatment. Finally, the present results suggest that diet containing 200 200 mg EP extract per kg food could improve growth, hematology, immunity and resistance against photobacteriosis of grey mullet

Estimation of hormone residuals (B-Estradiole) in rainbow trout

Residual level of 17- Beta Stradiol and progesterone hormones in rainbow trout fish plasma were measured during different period using RIA method. Blood sampling from abdominal aorta were taken from 70 individual of female fishes (100±11 g) which had been exposed to hormone at 0.5, 1,2,4,8,12,24 and 168 h (7 groups) compared with control group which was not exposed to this hormone. Results showed that plasma hormones measurement in different fish groups after exposing had significant differences (P<0.01) and the highest and lowest 17-Beta Stradiol hormone residue were observed in fishes that exposed 0.5h and 168h to hormone respectively (121±9 ng. ml^-1 and 3±0.9 ng. ml^-1) but there is no any differences between fishes exposed 168h to hormone and control group. Also the highest progesterone hormone level were measured in fishes 0.5 an 1h exposed and the lowest one was in fishes 168 h exposed. The range of progesterone hormone were between 0.3 to 1.1 ng .ml^-1 and significant increasing of this hormone levels were obtained in fishes exposed to hormone 4 to 24h (P<0.01). As consequence these hormone can not residue in fishes for a long time and maximum after one week the levels back to the normal

The production of all-female in rainbow trout (Oncorhynchus mykiss) using indirect feminization

The sex reversal technique in fish is widespread in many countries. The development of these techniques is desirable because rainbow trout males reach their gonad maturity earlier compared to the females. Rainbow trout alevins were treated with 17α-methyltestosterone incorporated in the diet (0.5. 1.5, 3, 6 and 10 mg/kg) for 60 days from the beginning of first feeding. Sex was determined at 180 and 680 dpf by sampling fish (n = 20) from each group and examining gross gonadal morphology under a dissecting microscope. Also sex reversal ratio and growth performance were determined in hormone-treated groups. These sex reversed functional males were reared for brood stock until they attained sexual maturity. At the end of experiment, normal rainbow trout eggs were fertilized with the sperms taken from sex reversed males for producing all-female populations. Examination of the results showed that 17α- methyltestosterone was effective in all treatment. The highest sex reversal ratio with 100% was observed in group treated with 0.5, 1.5 and 3 mg/kg 17α- methyltestosterone. The highest live weight ratios were observed in groups fed with 6, 0.5 17α-methyltestosterone and control group. Female progeny produced from the sex reversed males were 100 % in all males that sired offspring. All female trout stocks produced by this method have advantage in rainbow trout culture since the fish is not meant for direct human consumption and is used to generate brood stock, therefore, difference of growth parameters do not influence the success

Reproductive maturation of sub adult Indian carps in earthen ponds

Carp culture in extensive and semi-extensive systems: i.e., earthen ponds, natural and semi-natural water resources, reservoirs and the paddy field has widspred distribution. Indian major carps including Catla (Catla catla), Roho (Labeo rohita), Mrigal (Cirrhinus mirgala) which have faster growth and good feed value than other warm water fishes introduced to many countries including India, Thailand, Burma, Philippines, Japan and the former Soviet Union are also considered and are reared. Sex steroids are important in the control of reproduction in fish. Development of methods for Indian education programs for proliferation requires knowledge of the hormonal changes during sexual maturation and spawning is. Testosterone, progesterone and 17 ϐ-estradiol are steroid hormones that play an important role in controlling Tuesday reproduction and sexual maturity of the fish are. This study aimed to investigate the changes in steroid hormones testosterone and 17 beta-estradiol including Catla (Catla catla), Roho (Labeo rohita), Mrigal (Cirrhinus mirgala) were conducted in different seasons. 40 specimen of carps breeders were investigated in southern (Aquaculture Research Institute) and north (North Aquaculture Research Institute) of Iran and maintained in different seasons (spring, summer, autumn, winter). Fish were caught by netting vetch and spring 1 cm. Blood samples were collected from the fish caudal blood serum by centrifugal separation model Labofuga 200 was made in Germany. Testosterone, and estradiol RIA (Radioimmunoassy) using an automatic gamma counter LKB model made in Finland made in France using the Immunotech kit hormone were measured. The results showed that the average level of 17 betaestradiol in the female in the spring, summer, autumn and winter, respectively, 82/12 ± 75/107, 66/13 ± 2/80, 73/17 ± 8/122 and 72/17 ± 25/104 ml, respectively. Mean testosterone levels in the female in the spring, summer, autumn and winter, respectively, 004/0 ± 092/0, 002/0 ± 05/0, 003/0 ± 11/0 and 006/0 ± 1/0 ng ml, respectively. Overall, the highest levels of 17 beta-estradiol and testosterone in female Roho were recorded in autumn. Also, low levels of 17 beta-estradiol and testosterone in female Roho was observed in summer. Highest and lowest levels of the male hormone, respectively, were recorded in winter and spring. The relationship between the hormone 17 beta-estradiol and testosterone with environmental factors such as pH and dissolved oxygen were discussed. there was a positive correlation between testosterone levels in males only the amount of dissolved oxygen .results revieled that sex hormone levels were increased during winter and autumn would be the signe for reproductive performance and spawning seasone in three species