نوع مقاله : علمی پژوهشی- تغذیه طیور
1 فارغ التحصیل علوم دامی. گروه کشاورزی. دانشگاه پیام نور. تهران.ایران
2 گروه علوم دامی. دانشکده کشاورزی. دانشگاه پیام نور. تهران.ایران.
عنوان مقاله [English]
Introduction: Selenium is an essential trace element that is indispensable for normal functioning of the body and thus plays a critical role in the maintenance of optimal health. It is known to have important role in a number of biological functions, such as antioxidant defense, immune function, reproduction and thyroid hormone metabolism. Eggs and meat are considered to be good sources of Se in human diet. Egg Se content can easily be manipulated to give increased levels, when organic selenium as selenomethionine is included in layer diets. Recently, Nano-Se which is bright red, highly stable, soluble has attracted widespread attention because nanometer particulates exhibit novel characteristics such as a large surface area, high surface activity, high catalytic efficiency, strong adsorbing ability, high bioavailability and low toxicity. It is also, Selenium concentration of whole eggs, yolks and albumins higher in selenomethionin-fed laying hen than in sodium selenite. Also, research has shown that the addition of organic selenium to the diet of commercial laying hens significantly increases the selenium concentration in egg yolk and egg albumins. Since there is little information about the antioxidant effects of selenium nanoparticles on antioxidant status in laying hens, the main goal of this study was to compare the antioxidant effects of nano-selenium in laying hens and the oxidative stability of eggs during storage in the warehouse was.
Materials and Methods: This experiment was carried out in a completely randomized design with 4 treatments, 4 replicates and 10 birds per experimental unit in a total of 160 laying hens of HY-Line W36 from 30 weeks of age. The experimental diets included: 1- control diet 2- control diet plus 0.2 mg/kg nano selenium 3- control diet plus 0.3 mg/kg selenium 4- control diet plus 0.5 mg/Kg, nano selenium was available to experimental birds for 8 weeks. Performance parameters including, egg percentage, egg weight, feed intake and feed conversion coefficients were calculated for the whole trial period. At the end of the experimental period, blood parameters and yolk metabolites from each experimental unit including: blood serum metabolites and yolk metabolites were also calculated. The blood serum metabolites tested included: determination of malondialdehyde, total cholesterol, total triglyceride, aspartate aminotransferase, alanine transferase and total antioxidant. Egg yolk metabolites were tested to determine the concentration of yolk selenium and yolk fat proxide number. Data from blood metabolites and yolk metabolites were analyzed in a completely randomized design, under the GLM procedure, using statistical software version 1/9 (SAS, 2003). Mean comparison was done using Tukey test at 5% level.
Results and Discussion: The results showed that the addition of nano selenium increased egg production and improved feed conversion ratio. Effects of different levels of nano selenium on serum malondialdehyde, cholesterol, triglyceride, aspartate aminotransferase and alanine aminotransferase were not significant. Supplementation of diet with 0.5 mg / kg Nano selenium showed the highest selenium in yolk. Serum antioxidant capacity increased curvature by increasing the level of nano selenium up to 0.3 mg/kg feed, but decreased by 0.5 mg/kg feed. Peroxidation of yolk fat was influenced by storage time and experimental treatments, so that levels of 0.2 and 0.3 mg of nano selenium caused a significant decrease in egg malondialdehyde on day one and 15 days after storage. Other biochemical parameters of serum were not significantly affected by experimental treatments.
Selenium has shown to increase the activity of glutathione peroxidase and decrease the sensitivity of yolk to oxidative damage during storage, and selenium, by slowing down the process of carbon dioxide removal from the crust, reduced the weight loss and increased the unit size, thereby reducing egg corruption. Increasing levels of selenium can have toxic effects on the antioxidant capacity of the body. It has been reported that high nano-selenium levels induce oxidative stress and possibly increase free radicals and increase serum lipids malondialdehyde.
Conclusion: The results of this study indicate that addition of nano selenium up to 0.3 mg / kg can, improved feed conversion ratio and increase egg production egg storage time by increasing the egg yolk selenium level by preventing the peroxidation of the lipids. Nano selenium used in the proposed levels in this study, improved the health of laying hens by increasing the antioxidant capacity of the serum.
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