J. Illek

Influence of organic versus inorganic dietary selenium supplementation on the concentration of selenium in colostrum, milk and blood of beef cows

BackgroundSelenium (Se) is important for the postnatal development of the calf. In the first weeks of life, milk is the only source of Se for the calf and insufficient level of Se in the milk may lead to Se deficiency. Maternal Se supplementation is used to prevent this.We investigated the effect of dietary Se-enriched yeast (SY) or sodium selenite (SS) supplements on selected blood parameters and on Se concentrations in the blood, colostrum, and milk of Se-deficient Charolais cows.MethodsCows in late pregnancy received a mineral premix with Se (SS or SY, 50 mg Se per kg premix) or without Se (control – C). Supplementation was initiated 6 weeks before expected calving. Blood and colostrum samples were taken from the cows that had just calved (Colostral period). Additional samples were taken around 2 weeks (milk) and 5 weeks (milk and blood) after calving corresponding to Se supplementation for 6 and 12 weeks, respectively (Lactation period) for Se, biochemical and haematological analyses.ResultsColostral period. Se concentrations in whole blood and colostrum on day 1 post partum and in colostrum on day 3 post partum were 93.0, 72.9, and 47.5 μg/L in the SY group; 68.0, 56.0 and 18.8 μg/L in the SS group; and 35.1, 27.3 and 10.5 μg/L in the C group, respectively. Differences among all the groups were significant (P < 0.01) at each sampling, just as the colostrum Se content decreases were from day 1 to day 3 in each group. The relatively smallest decrease in colostrum Se concentration was found in the SY group (P < 0.01).Lactation period. The mean Se concentrations in milk in weeks 6 and 12 of supplementation were 20.4 and 19.6 μg/L in the SY group, 8.3 and 11.9 μg/L in the SS group, and 6.9 and 6.6 μg/L in the C group, respectively. The values only differed significantly in the SS group (P < 0.05). The Se concentrations in the blood were similar to those of cows examined on the day of calving. The levels of glutathione peroxidase (GSH-Px) activity were 364.70, 283.82 and 187.46 μkat/L in the SY, SS, and C groups, respectively. This was the only significantly variable biochemical and haematological parameter.ConclusionSe-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in the blood, colostrum and milk, as well as the GSH-Px activity.

Concentrations of Mineral Substances in the Tibiotarsus of the Japanese Quail in Weightlessness

Ivanova I. Ye., T. A. Derendiayeva, G. I. Meleshko, Yeo Ya. Shepelev: Higher Plants in a Biological Life SupportSystemfor Man. Acta vet. Bmo 1996,65: 27-32. A model of human biological life support system (BLSS) was created with a photoautotrophic link including unicellular algae and higher plants having an equal oxygen production. This system model supported the vital activities of two people at the biomass regeneration of 92% from that consumed by them. The plant cultures studied were wheat grown on 11.25 m2 (of a total 15 m2) and several vegetable species. The total photosynthetic productivity of the plants was high, stable over the studied time span, and independent on the composition of the system. However, the grain productivity of wheat decreased periodically, and during certain harvests it decreased to almost zero. A detailed analysis revealed that this decrease was not caused by any of the systems adjacent links as a similar decrease in yield was also found in the control period with an autonomous growth of the plants in a closed volume of a chamber. Inclusion of bigher plants into BLSS led to a considerable improvement od food supply regeneration for man as compared to the previous model with only 26% regeneration effect. This inclusion did not exert any marked effect upon the general closure of the cycle. However, the biological value of the food for man was increased dramatically. This improvement is the main goal of designing and operating such BLSS systems. Regeneration. ecosystem. photosynthesis, photoautotroph link, unicellular algae. higher p.lants The prospect of long-teon existence of man outside the Earths biosphere (interplanetary flights, lunar and planetary bases) is connected with creating an artificial environment with the help of regenerating it from the products of vital activity. This environment must correspond to the evolutionarily conditioned biological needs of the humans and to provide their lives for generations. The fact of adaptive biology shows that the full-value environment for humans and other terrestrial organisms is the natural environment of the Earth. In order to recreate that environment artificially it is necessary to reproduce the mechanisms existing on Earth, i. e. to foon closed ecological systems including man. The lack of our knowledge about the natural environment of the humans prevents us from reproducing it by non-biological means, even if it were possible. The investigation of the problem of creating biological life-support systems (BLSS) of man began as early as in the 60ies. By the present time, experimental BLSS models have been created with different structures and different degrees of the cycle closure. , The creation of the systems was based on the ecological concept according to which strategy and tactics were worked out providing the organisms and populations were studied and then united into biocenoses, including also humans. The main method of solving the problem was the method of experimental modelling from the simple to the complex (Rashevski 1966).