The control of recovery process with clove tree (Eugenia caryophyllata) in rainbow trout (Oncorhynchus mykiss)

In order to investigate the effect of different temperature of anesthetic (clove tree) and recover (anesthetic-free water) solutions on recovery process, The anesthetic induction times and recovery times of 540 fingerlings of rainbow trout (Oncorhynchus mykiss) weighing 3.2 ± 0.2 g in anesthesia/ recovery solutions with cross-combined of temperature of 5,11 and 17 °C as experimental treatments (9 treatments) were compared. The anesthesia was induced by170 ppm of aqueous clove (Eugenia caryophyllata) solution. Results showed that both induction and recovery times were adversely temperature-dependent. Recovery times of treatments, related to temperature of anesthetic solutions and their temperature, were significantly different (P < 0.05). Our results indicated that mean recovery time (three temperature treatments) of the fish exposed to the lower temperature anesthetic solutions generally decreased opposing with higher anesthetic solutions. The lowest recovery time (61±11.1 seconds) in17°C anesthetic-free water occurred in fishes induced to 5°C anesthetic solution. In contrast, the highest recovery time (523±154 seconds) in 5°C water happened in fishes induced to 17°C anesthetic solution. Warm and cold thermal difference in anesthetic and recover solutions could extend recovery time 1 up to 8 minutes. Regarding to aim and demanded time, by selected favorite temperatures can control anesthesia/or recovery time in order to prevent the use of drug over-dosing

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

Investigation of chromosome and ploidy levels of rainbow trout produced from imported eyed eggs

Rainbow trout is the main cultural species of coldwater fishes in iran. Often, aquaculturists intend to breeding in order to production of lines with higher growth rate potential and disease resistant. Nevertheless in the country, no trout breeding programs, has been performed yet and most of the farms focused on the cultivation of the first (unbred) race. While European countries progressed in trout breeding techniques and production lines with higher growth through genetic manipulation (chromosomal number and type changes of fish) and/or selection and their fish products derived from this technology, including eyed eggs and so on have sold to other regions of the world (eg: Iran). In this study, some biological parameters including survival, growth, feed conversion ratio (FCR.) and chromosomal number of two juvenile groups from imported( group 1) and native(group 2) eyed fish eggs were compared. For chromosomal investigation, blood smear test and flow cytometry were performed. sults showed a significant difference (P≤5%) in growth rate of native fishes and French group Native fish feed conversion ratio (0.9) was significantly difference (P≤5%) from that of French fishes (1.15). Chromosomal analysis showed no difference in chromosome number in treatments and two fish groups were 2n chromosome. Based on the results, the fishes of group 1 had faster grow potential and gain weight in less time than that of group 2 and this has been achieved to go through the process of selection and feminization without any change in number of ploidy. Whereas the ability of native fishes in food efficiency ( lower FCR.) was better. However, the reduction of rearing period is the benefit and preference of cultivation of imported or origionally foreign

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

Evaluation of sperm quality and different nutrient levels on sperm efficiency in male rainbow trout

Considering the importance of rainbow trout (Oncorhynchus mykiss) in supplying required protein of people and effort to increase the efficiency of these fish reproduction, some related factors such as sperm quality and potential fertility of male are necessary. The aim of this study was to find out the effects of different dosages of Arginine on the biochemical parameters (including LDH, AST, ALT, ALP, iron, magnesium, phosphorous, chloride, calcium, sodium, Potassium, cholesterol, uric acid, urea, fructose, glucose, total protein and pH) of rainbow trout seminal plasma. For this purpose, five practical diets (each consisting of 3 triplicates) were supplemented with Arginine at 0.00 (Control), 0.50, 1.00, 1.50 and 2.00%. Broodstock feed last for 90 days. At the end of the feeding period one fish was captured from each replicate in order to collect their semen. Results indicate that there were no significant differences in LDH, ALP, Fe^2+ and P content among different treatments. The lowest level of AST and ALT and the highest level of Ca^2+ and Mg^2+ ions were observed in the treatment fed with 1.50% of Arginine which showed significant differences with other treatments (p<0.05). Moreover, the amount of Cl^-, Na^+ and K^+ ions were significantly increased in the seminal plasma in fish which were fed on diets containing arginine in comparison to control. As the amount of Arginine were increased, the levels of uric acid stepped up significantly in contrast to the urea and glucose. The highest amounts of cholesterol, fructose and total protein were observed in the treatments fed on 2.00, 0.50 and 1.00% of Arginine, respectively, that showed significant differences with other treatments (p<0.05). The highest pH value was assayed in the 1.50% of Arginine treatment. The results of the Pearson correlation coefficient showed a significant positive correlation between Ca^2+ and Mg^2+ ions and Na^+ with K^+ and Clions (r=0.750, r=0.769 and r= 0.938, p<0.01), respectively. On the other hand, a significant negative correlation between cholesterol with Cl^-, Na^+, K^+, ALT and LDH (r=- 0.764, r=-0.724 and r=-0.728, p<0.01) and (r=-0.531 and r=-0.560, p<0.05) and also a significant positive correlation between K^+ and Clions (r=0.836, p<0.01) were observed. Finally, it can be expressed that the levels of most of the ions were increased and there was a reduction in the levels of enzymes in seminal plasma of fish which were fed with practical diet including 1.5% of Arginine. So it can be recommended that adding this value of Arginine to the diets of rainbow trout broodstock, would improve the sperm quality which results in the enhancement of efficiency in rainbow trout reproduction