جستجوی مقالات مرتبط با کلیدواژه "سلنیوم" در نشریات گروه "شیلات"

The aim of this study was to evaluate the effect of different levels of organic and mineral sources of selenium on the intestinal morphology and also histologically changes in liver tissues of juvenile rainbow trout for 60 days. For this purpose, 1080 healthy fry fish (50±2.8 g average body weight) were randomly divided into 3 groups, including organic selenium (0.15, 0.30, 0.45, 0.60 mg. kg-1), mineral selenium (0.15, 0.30, 0.45, 0.60 mg. kg-1) and a control group with triplicates. At the end of trial, 3 fish were caught in each treatment. After anesthesia, the fish were autopsied. The liver and intestine of fishes were removed and histologically studied by standard tissue procedures. Finally, prepared tissues were evaluated by optical microscopy. The microscopic and morphometric results indicated a significant improvement in the morphological changes of the intestinal tissue including the auxesis of absorption area, length and diameter of villi and abate of depth of villi crypt in treatment containing 0.45 mg. kg-1 organic selenium of diet compared with other treatments and control group (p<0.05). Also, the least histopathological changes of liver tissue in the treatment containing 0.45 mg. kg-1 organic selenium in diet and the most extensive lesions wereobserved in both the control group and higher levels of dietary mineral selenium. It seems that, the treatment containing 0.45 mg. kg-1 organic selenium in diet were identified as the best supplement for improving of the intestinal tract and decrease in possible histopathological side effects in rainbow trout.

In this study, the effect of different dietary levels of selenium on the growth of survival and muscle chemical composition of rainbow trout (Oncorhynchus mykiss) with an average weight of  80±0.57 g was investigated for 60 days. 320 fish were distributed randomly in 12 fiber tanks of 1500 L. Selenium was added at four levels, no selenium (control), 0.5 (treatment1), 1.5 (treatment2), and 3 (treatment3) mg/kilogram and the fish were fed for 6 weeks. The results showed that the specific growth rate, percentage of body weight gain, average daily growth, and food conversion ratio in the treatment fed with a diet containing 3 mg/kg selenium were significantly different from the control (p<0.05). There was no significant difference in the survival index between the investigated treatments and the control group (p>0.05). The effect of adding selenium on the chemical composition showed a significant difference in the level of carcass protein (p<0.05). The highest value related to treatment 4 (18.20±0.57 %) and the lowest value related to control group (16.47±0.16 %). In the treatments fed with selenium, a decrease in rainbowtrout fat was seen, which was significantly different from the control group (p<0.05). The moisture and ash levels in the control group were not significantly different from other treatments (p>0.05). The highest effect of selenium on growth was related to treatment 4 (3 mg/kg of selenium), but there was a significant difference with treatment 3 (1.5 mg/kg selenium) did not have (p>0.05). Overall, the results of this research showed the positive effect of adding 3 mg/kg selenium to the diet on the growth indices and improving the chemical composition of the rainbow trout.

Selenium is a non-metallic element and a kind of essential micronutrient for the body, which has chemical properties similar to oxygen and sulfur. Due to its unique physical, chemical and biological characteristics, it plays an important role in the ecosystem cycle of running and sea waters. Selenium is one of the low-requirement substances for animals, which as a cofactor in the structure of glutathione peroxidase enzyme plays an essential role in inhibiting the destructive effects of free radicals in the body and is vitally important in the antioxidant defense system, thyroid hormones and insulin function, regulation It has cell growth and fertility maintenance. Today, selenium-containing diets have received much attention in the feeding of aquatic animals. It is important to use the appropriate selenium supplement in the diet to improve the performance of aquatic growth and physiological and biochemical functions in fish. Selenium is used in inorganic, organic and nano forms in fish feed, but the use of inorganic selenium in fish food formula has been more than other forms.

In the present study, the effects of different levels of dietary antioxidant supplements on growth performance and biochemical indices in rainbow trout (Oncorhynchus mykiss) fingerlings were investigated. For this aim, nine experimental diets were formulated and supplemented with different combinations of three antioxidants including vitamin E (VE) at levels of 0, 100 and 150 mg kg-1 diet), coenzyme Q10 (CoQ10) at levels of 0, 10 and 20 mg kg-1 diet and selenium forms (mineral, organic and nano-selenium (Nano-Se)) at levels of 0, 0.3 and 0.5 mg kg-1 diet. The fish were randomly divided into these diets with stocking density of 25 per replicate and fed for 56 days. Based on the results, a relative increase was observed in the growth indices of fish fed with the treatment containing 0.5 mg Nano-Se + 100 mg VE. The highest of glucose content was obtained in supplemented treatment with 0.5 mg Nano-Se + 100 mg VE. For cholesterol and triglyceride, the highest values were reported in fish fed with treatments containing 0.5 mg mineral Se + 150 mg VE + 20 mg CoQ10 and 0.5 mg Nano-Se + 100 mg VE, respectively. Similarly, the highest values ​​of HDL and VLDL indices were observed fish fed with 0.5 mg Nano-Se + 100 mg VE. In contrast, the control treatment showed the highest LDL value. The results of this study revealed that supplemented diet with Nano-Se at level of 0.5 mg and VE at level of 100 mg can be effective in improving the growth and blood biochemical indices of rainbow trout.