The Biological Effect Of Nano Selenium On Avian Broiler And Approach To The Molecular Mechanism

Nano-Se is the nano particle of elementary selenium(Se? that dispersed by protein. Chicken's kidney cells and Avian broilers were used to study the effects of Nano-Se ( Na₂SeO₃ and Se-Met as controls ) on the activity of GPx in cell and its influence to anti-oxidation ability , immunity, hormone level, tissue selenium concentration, muscle quality , growth performance , as well as its influence to the expression abundance of GPx and ID I gene in liver tissue, were investigated. In vitro trial (cell culture), basic medium M199, which include 5% PCS, was adapted, and 0.01, 0.05, 0.10, 0.20, 0.30 mol/L selenium were added, respectively. GPx activity was determined after incubated 24 h, 48 h, 72 h, and 96 h. In rearing trial, 2160 Avian broilers were randomly allotted to 16 groups, each of which was replicated three times. One group received the basal diet, the other groups received the same basal diet and supplemented with 0.10, 0.20, 0.30, 0.40, 0.50 mg/kg selenium(Nano-Se, Na₂SeO₃, Se-Met). After 6 weeks, six Avian broilers in each treatment were selected based on similar live weight and slaughtered for determining the indexes of anti-oxidation, immunity, muscle quality, tissue selenium, hormone, activity of GPx and ID I in liver, mRNA level of GPx and ID I in liver. The followings were main results.1. The results of cell culture trial showed that in the range of 0.01 0.10 u mol/L, there are no difference in the GPx activity of the same concentration but different forms selenium, and the GPx activity is increasing with the changed of concentration, which showed the effect-dose relation. When the concentration of Na₂SeO₃>0.10 mol/L, Se-Met > 0.20 mol/L, selenium inhibits of the activity of GPx, which changes with the increase of selenium concentration and culture time. However, in the concentration range of 0.1 0.3 mol/L, Nano-Se can constantly keep the GPx activity at the highest point. It implicates that the security of Nano-se is higher than the other chemical states at super dose added in cell culture medium; the range of selenium concentration of Nano-Se is wider than that of Na₂SeO₃ and Se-Met that can maintain the GPx activity at high level.2. The results of rearing trial showed that there were no difference in performances among the groups of Nano-Se, Se-Met and Na₂SeO₃ (p>0.05) when added seleniumconcentration was≤0.40mg/kg. The performance of Nano-Se group was higher than the groups of Se-Met and Na₂SeO₃ (p<0.05) when 0.50 mg/kg selenium was added in basal diet.3. The analysis of anti-oxidation capacity showed that there is no difference in anti-oxidation capacity among three forms of selenium (p>0.05) when added selenium concentration was≤0.40mg/kg.. Adding 0.50 mg/kg Se-Met and Na₂SeO₃ to basal diet,the activity of GPx and T-AOC were descending and the level of O₂ and MDA were higher compared with adding 0.40 mg/kg Se (same Se form) (P<0.05). Nano-Se group did not show any difference.4. The analysis results of the muscle quality showed that adding 0.50 mg/kg selenium, Nano-Se could depress the loss of drop water(P<0.05), increase red chroma and content of myoglobin(P<0.05) in breast muscle compared with Se-Met and Na₂SeO₃5. The results of determination on serum immunity index showed that Nano-Se made IgG content increased compared with Se-Met and Na₂SeO₃ when adding 0.20, 0.30, 0.40, 0.50 mg/kg Se (p<0.05) to basic diet. Nano-Se made IgM content increased compared with Na₂SeO₃(p<0.05). There was no difference in IgA content among these three forms of selenium (p>0.05).6. Adding 0.50 mg/kg selenium to basal diet, the content of-insulin in serum for Nano-Se group was higher than the controls (p<0.05).7. There was no difference on the levels of T₃, T4, TSH in serum, the activity of ID I in liver tissue and tissue selenium concentration among the three forms of selenium(P>0.05).8. The experiment results of molecular biology show that when 0.50 mg/kg selenium was added to b...