Saifeldin Hassan

Biopotency of vitamin E in barley.

Investigations were carried out to establish the total biopotency of the natural vitamin E isomers in barley compared with that of DL-alpha-tocopheryl acetate. The chick was used as an experimental animal. Prevention of nutritional encephalomalacia (NE) and chick liver-storage and plasma-storage assays of vitamin E were the methods used in the study. The individual tocopherols and tocotrienols, both in the tissue samples and in the grain and barley oil, were analysed using high-pressure liquid chromatography (HPLC) with fluorescence detection. The diagnosis of NE was based on careful clinical and histopathological observations. It can be concluded from the results that full protection against NE in the chicks was obtained with a supplementation level of 7.5 mg DL-alpha-tocopheryl acetate/kg diet (i.e. a total vitamin E content of 11.20 mg/kg diet) or with a supplement of 8.7 g barley oil/kg diet (i.e. a total vitamin E content of 22.99 mg from barley oil/kg diet). This gave a biopotency factor of 0.49 for barley for prevention of NE of the chicks, as compared to that of DL-alpha-tocopheryl acetate. Using regression analysis a statistically linear relationship could be observed between the total dietary vitamin E level and the response, as measured by the total vitamin E content in the liver and plasma, both in the groups supplemented with DL-alpha-tocopheryl acetate and in the groups supplemented with corresponding amounts of vitamin E in barley oil. The liver and plasma responses to the total vitamin E in the barley-oil diet compared with those of the DL-alpha-tocopheryl acetate reference diet gave identical values for the regression coefficients, i.e. in both liver-storage and plasma-storage assays the value for slopes of dose-response lines was 0.37. This means that the biopotency of the total vitamin E in barley was 37% of that of dietary DL-alpha-tocopheryl acetate. Thus, barley is not as rich a source of vitamin E as could be supposed on the basis of the chemical determination of its total vitamin E content. It was possible to verify this experimentally established biopotency of 0.37 for the total vitamin E in barley by converting the chemically determined amounts of the vitamin E isomers in barley into DL-alpha-tocopheryl acetate equivalents by multiplying them with internationally accepted potency factors for the individual natural isomers (DL-alpha-tocopheryl acetate 1.00, D-alpha-tocopherol 1.49, D-beta-tocopherol 0.60, D-gamma-tocopherol 0.15, D-alpha-tocotrienol 0.37).(ABSTRACT TRUNCATED AT 400 WORDS)

Selenium Concentration in Egg and Body Tissue as Affected by the Level and Source of Selenium in the Hen Diet

Abstract This study was carried out to determine the effect of three dietary selenium (Se) supplemental levels (0.20, 0.40 and 0.60 mg/kg), provided as sodium selenite or barley Se to low-Se basal diets on the concentration of Se in the edible egg components and body tissue of laying hens. The Se concentration in whole egg, egg yolk and egg white was determined at 0, 5, 10, 15 and 20 weeks, while tissue Se concentration was observed only at 20 weeks of Se treatment. Hens fed the low-Se basal diets had significantly lower Se concentrations in the whole egg and edible egg components than did hens receiving a supplement of 0.20 mg Se from sodium selenite or barley Se/kg diet. A slight or significant (p<0.05) increase in egg Se concentration was observed with each increment in dietary Se from either sources. At all supplemental levels, hens fed barley Se had a higher or significantly (p<0.05) higher concentration of Se in whole egg, egg white and yolk than did hens fed sodium selenite. The Se concentration wa...

Influence of dietary sodium selenite and barley selenium on the performance of laying hens and their subsequent progeny

Abstract The study was conducted to investigate the effect of dietary selenium (Se) deficiency and supplemental Se as sodium selenite or Se-enriched barley on the performance of laying hens and their subsequent progeny. Low-Se basal diets (0.03 mg/kg) were fed alone or supplemented with 0.20, 0.40 or 0.60 mg Se/kg provided as sodium selenite or Se-enriched barley, for 20 weeks to White Leghorn laying hens with initially low-Se status. Egg production and hatchability were significantly (p 0.05) differences were observed in the hens with regard to feed consumption, egg and body weight or fertility as a result of these dietary treatments. Increasing the dietary Se supplementation above 0.20 mg/kg had no adverse effect on hen per...

Response of whole blood glutathione peroxidase and selenium in chicks fed with sodium selenite, wheat and fish meal

Abstract The biological availability of selenium (Se) in wheat and fish meal in comparison with that in sodium selenite was estimated in the chick. Newly hatched White Leghorn chicks with a low-Se status were fed a low-Se basal diet for 2 weeks post-hatching, followed by either continued depletion or a repletion period of 4 weeks with graded levels of Se (0.03, 0.06, 0.09 and 0.12 mg kg −1 ) provided via sodium selenite, wheat or fish meal. The efficacy of Se from these sources in inducing glutathione peroxidase (GSH-Px) activity and in increasing Se concentration in whole blood were used as indices. A slope ratio assay was employed to obtain estimates of the biological availability of Se in wheat and fish meal in comparison with the sodium selenite standard (100%). The bioavailability of Se in wheat and fish meal for increasing the activity of GSH-Px, when calculated as units per millilitre was 78% and 58%, respectively, and 81% and 54%, respectively, when this enzyme activity was calculated as units per gram of haemoglobin. The efficiency of wheat and fish meal Se for increasing Se concentration in the whole blood was 123% and 107%, respectively. Even though the Se obtained from wheat and fish meal was retained more in whole blood than was the Se from sodium selenite, its utilization for the synthesis of GSH-Px was inferior.