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The experiment was conducted to investigate the effect of different doses of deoxynivalenol on plasma indices of broiler chickens. Forty-two one-day-old male broiler chicks were fed 1 of 3 diets containing deoxynivalenol (DON) for 42 d. The diets included: (1) control (0.2 ppm of deoxynivalenol), (2) low level of deoxynivalenol (1 ppm of DON), and (3) high level of deoxynivalenol (3 ppm of DON). Then, all the birds were sacrificed and blood samples for biochemical analyses were collected. The mycotoxin doses in diets were verified using gas chromatography-mass spectrometry. The administration of 1 ppm of DON altered total protein, triglycerides, free glycerol, and potassium levels. Dietary addition of 3 ppm of DON resulted in altered calcium, potassium, total protein, triglycerides, along with free glycerol levels, and aspartate aminotransferase activity. No biochemical parameter, however, responded to increased DON concentration in the diet. The feeding of DON-containing diets did not significantly alter plasma chloride, cholesterol, and albumin levels or aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase activities. It was concluded that both levels of deoxynivalenol in the diets tested significantly affected protein and lipid metabolism in broiler chicks.
The experiment was designed to investigate the effects of feed supplementation with selenite or selenized yeast on parameters of antioxidant and selenium status of laying hens. Hens of laying breed Shaver Starcross 288 were randomly divided at the day of hatching into 4 groups and fed for 9 months on diets which differed only in amounts or forms of selenium supplemented. Group 1 was fed the basal diet (BD) with native Se content 0.1 mg.kg-1 DM. Groups 2 and 3 were fed the BD diets supplemented with equivalent Se dose 0.4 mg.kg-1 DM of either sodium selenite or Se-yeast, respectively. The diet for group 4 was supplemented with Se-yeast at Se dose 0.9 mg.kg-1 DM. The activities of glutathione peroxidase (GPx) in blood and tissues of liver, kidney and duodenal mucosa were significantly increased by Se supplementation, but no differences due to form or dose of Se were observed. Both Se sources resulted in significant reduction of superoxide dismutase (SOD) activity in erythrocytes. Malondialdehyde (MDA) content in kidney tissue was reduced by both Se sources, but its production in liver tissue was inhibited by Se-yeast only. Selenium supplementation did not influence the levels of MDA and -SH groups in plasma. Altrough both Se significantly raised Se concentrations in blood and tissues of liver, kidney, spleen, hearth and duodenal mucosa, significant Se deposition into muscles appeared in hens given Se-yeast only. The presented results suggest that Se-yeast is more effective in maintenance of antioxidant and selenium status of laying hens than selenite.
The influence of dietary CLA isomer(s) and/or selenized yeast on the growth, concentration of CLA isomers and other fatty acids in the liver was investigated in rats. Plasma blood triacylglycerols (TAG), total cholesterol (TC), HDL and LDL cholesterol fractions in relation to dietary CLA isomer(s) and/or selenium (Se) were analysed. The experiment was performed on female rats (Wistar), 8 weeks of age and initial body weight of about 200 g. After a 1-week preliminary period, for 4 weeks the animals were fed a diet enriched in conjugated linoleic acid (CLA) isomer(s) and selenized yeast (2×2 experimental design). Dietary Se or/and CLA isomer(s) resulted in small changes in the spleen, heart, kidneys and brain, and increased liver weight. Administration of Se and trans10cis12CLA most efficiently increased the body weight gain of rats. CLA isomer(s) administered with or without Se elevated the CLA isomer(s) level in the liver. These results demonstrate that trans,transCLA isomers are metabolized more slowly, while cis,trans/trans,cisCLA isomers, more rapidly to longchain fatty acids containing a conjugated double bond. Enrichment of the diet in CLA isomer(s) with or without Se caused a reduction in the capacity of Δ9-, Δ6- and Δ5-desaturases in the liver, while dietary trans10cis12CLA or the CLA isomer mixture increased Δ4-desaturases. The contents of oleic acid, C20:4n-6, and C20:5n-3 decreased in the liver, whereas the level of C22:5n-3 and C22:6n-3 increased in the liver of rats fed the CLA isomer mixture. Individual dietary CLA isomers with or without Se increased the concentration of palmitic and stearic acids in the liver. All experimental diets increased the concentration of triacylglycerols in blood plasma, while trans10cis12CLA with or without Se usually decreased the concentration of total cholesterol, LDL, and HDL cholesterol.
The activities of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), glutathione-S-transferase (GST) and glutathione reductase (GR) were examined in liver, kidney cortex and heart tissues of lambs fed diets supplemented with inorganic (sodium selenite) and an organic (Se-yeast) form of selenium. Additional selenium resulted in a significant increase of the Se content in the examined tissues in both supplemented groups. The activities of GSHPx, CAT in the liver as well as of CAT, GST and SOD in the kidney cortex were significantly lower in the Se-yeast supplemented group when compared with both the control and selenite-fed groups. In the heart, the activities of all of the assayed enzymes increased in both supplemented groups. SOD activity was found to be significantly higher in the Se-yeast supplemented group when compared with the selenite group. In addition, two Cu, Zn-SOD isoenzymes of higher band intensity were generated in this group, probably as a result of oxidative stress, which was also manifested by a significant increase of thiobarbituric acid reactive substances (TBARS). The presented results suggest specific regulation of antioxidant enzyme activities in the tissues of lambs depending on the form of selenium intake.
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