جستجوی مقالات مرتبط با کلیدواژه "rainbow trout (oncorhynchus mykiss)" در نشریات گروه "زیست شناسی"

The present study was evaluated to determine effects of levamisole on growth and resistance of rainbow trout against density stress. For this purpose 1000 pieces fish (average weight of 150±6 g) were obtained from a local fish farm of Urmia and were divided in 5 test groups (33 kg/m3 density) and were fed on diet supplemented with levamisole at 0, 100, 250, 500 and 1000 mg per kg of diet for a period of 45 days. Then the fishes of all groups were fed on commercial diet without levamisole and were exposed density stress by 2-3 folds for the following 15 days. Biometry of fishes was done every 15 days and growth factors were measured. Results show that high level of levamisole (1000 mg/kg) had the lowest effect on growth factors of fishes. The maximum survival percent of fishes were observed in 500, 250, and 100 mg/kg Levamisole at the end of research and the level 1000 mg/kg Levamisole caused increase mortality of fishes into control group in density stress significantly (P

The mechanism of compensatory growth in rainbow trout (Oncorhynchus mykiss) was studied in a completely randomized design with four experimental treatments and a control group (no food deprivation) with three replicates. Animals in treatments 1 to 4 were fed with rates of 0, 25, 50 and 75% saturation, respectively for two weeks. Then, the treatments were fed twice a day until saturation level for more three weeks. The results of growth indexes, chemical body composition and blood factors showed that rainbow trout could tolerate compensatory growth and feeding until 25% of saturation level.

In regarding to study the effect of biological parameters of female rainbow trout (Oncorhynchus mykiss</em>) brood stocks on girt, 30 specimen of rainbow trout brood stocks were selected from 3 different age class (3, 4, 5 years). The results showed, maximum of girt 36.35± 0.35cm , ovary weight 600±11.25 gr, hatching 90±4 % and larvae weight after hatching 0.15±0.01 were in 5 and 3 years old brood stocks, respectively. The results  showed significant  differences between 3,4 and 5 years old  brood stocks for this instances (P</em><0.05). Maximum of number of eggs in each gram 15±0. 26 Registered in 3 and 5 years old brood stocks, respectively. Maximum absolute fecundity, relative fecundity, and working fecundity were recorded in 4 and 3 years old brood stocks, respectively. The study pointed significant difference between investigated brood stocks (p<0.05). Maximum of larvae survival percentage were observed in 4 and 3 years old brood stocks, respectively. The results showed no significant difference between 5 and 3 years old brood stocks, but for 4 and 5 years old brood stocks was saw significant difference (P</em><0.05). Maximum of gonadosomatic index were observed in 5 and 3 years old brood stocks, respectively. Although gonadosomatic index between 4 and 5 years old fish showed no significant difference, but the study showed significant difference for 3 years old brood stocks (P</em><0.05).

Some biological aspects of semen were investigated in the rainbow trout (Oncorhynchus mykiss( during the out-of-season spawning, by determination of spermatological parameters, seminal plasma indices (ionic and organic composition) and fertilization success. The concentrations of Sodium (Na), Potassium (K), Calcium (Ca2), Magnesium (Mg2) and Chlorine (Cl-) ions were 60.87±28.22, 36.56±13.69, 4.33±1.19, 3.08±.88 and 71.96±27.60 MmL-1 respectively. Seminal plasma contained 0.26±0.13 g/dl protein, 2.69±1.54 mg/dl cholesterol, 2.33±0.86 mg/dl glucose, 6.46±2.45 mg/dl triglyceride and 11.04±9.31 mg/dl urea. The pH of seminal plasma increased from 6.72±0.32 in spawning season to 7.16±0.26 during the out-of-season spawning (P0.05). In the present study spermatological parameters, seminal plasma indices and fertilization success were investigated in reproductive season and out-of-season spawning. Although some spermatological parameters and seminal plasma indices altered during out-of-season spawning, but significant difference on fertilization success was not observed.

Inroduction & Prebioticdietary supplements that have the potential to reduce the harmful effects of infectious agents and have beneficial effects on host health. In this study, the prebiotic of yeast cell wall Saccharomyces cerevisiaat different levels to evaluate the blood indices and immune indices in rainbow trout juveniles were used.To conduct this study, 120 rainbow trout fry with a mean weight 3.61± 0.12 gr were randomly assigned into 12 fiberglass tub drainage volume of 100 ml distribution and breeding were given. An experiment to determine the optimum level of prebiotic effect of dietary yeast cell wall in the diet of rainbow trout fry in 1% prebiotic treatments, 1.5% prebiotic, 2% prebiotic prebiotic-free control, in a balanced design with three replications each were studied. At the end of the period rearing, blood indices and immune indices juveniles were studied.The results of some blood indices such as levels of White blood cells, Red blood cells, hemoglobin and hematocrit levels and neutrophil counts were not significantly different between the treatment and control groups were observed in 2% and other treatments (P0.05). The results showed that non-specific immune indices in blood, such as lysozyme and specific immune IgM and Ig statistically significant difference between treatment groups fed with 2 % prebiotic yeast cell wall with the other treatments and the control group (P Based onthese results it can be stated that the level of 2% prebiotic yeast cell wallused in thediet caused a significant increase in immune indices, andsomeblood parametersof studied, An important rolein immune function and improve blood indices of rainbow trout fry can play.

Silver Nanoparticles included 56 % of total manufactured Nanomaterials due to its anti-bacterial properties in the world. Therefore، the release of Silver Nanoparticles to water ecosystems will make an irreparable damage to biota، especially to natural bacterial flora. The purpose of this study is to investigate the Silver Nanoparticles effects on the bacterial flora of rainbow trout skin. To ensure the quality of the Silver Nanoparticles، the ICP، Zetasizer، TEM، EDX، and Uv-vis Spectrophotometer sets were used. Also، the population’s mesophilic bacteria، psychrophile، Enterobacteriaceae and Lactic acid bacteria (LAB) of skin after 14 days kept of fish in 1، 0. 1 and control group of Silver Nanoparticle concentrations were counted by pour plate method. Results of the study showed that the fish skin LAB bacteria decreased significantly with the increase of Silver Nanoparticle concentration and mesophile and Enterobacteriaceae were less affected. Whereas، population of fish skin psychrophile bacteria significantly increased with enhancing of Silver Nanoparticles concentration. Analysis of result suggested that according to the type of studied group of bacteria، an antibacterial property of Silver Nanoparticles is selective and different.