Calcium metabolism regulation in laying hens involves a complex of biochemical, nervous and hormonal factors. One of these factors is represented by the estradiol. Usualy it is accepted that estradiol is sinergic to parathormone in laying hens but the exact role of this hormone in the regulation of the calcium metabolism in laying hens isn't well understood (

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This study examined the changes in age at first oestrus, the weaning-to-oestrus interval (WEI), and duration of oestrus (DE) in a Yorkshire sow population during two years of adaptation from a northern (55°48′N, 9°13′W) European region to a southern (44°03′N, 23°35′W) one. The adaptation process induced a grouping effect of gilts around the mean age of the onset of puberty. Autumn and spring were characterized by the most enhanced gilt grouping effect at 201 to 210 days of age. The same effect was found for oestrus duration, which declined from a 12-to 96-hour range in the first year to an 18-to 90-hour range in the second year. The mean age of first oestrus was 0.8 days significantly lower in the second year compared with the first; the maximal lowering (1.7 days) occurred in the winter season. The WEI decreased significantly from the first to the second year in all four seasons, by a mean annual value of 0.88 days (15.9%). DE increased by 6.5 hours (significantly for all seasons) from the first year to the next. DE showed an ascending evolution from winter to spring and descending from summer to autumn, during each monitored year. Adaptation influences the oestrus in sows. The age to puberty and WEI tended to decrease, while DE tended to increase, with a simultaneous decrease in the variability of these oestrus parameters. ______________________________________________________________________________________

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Cadmium’s mechanism of toxicity is manifested by its fixation in mitochondria, inhibition of cellular respiration and oxidative phosphorylation. Vitamin E could act as a protective factor against the harmful effect of Cadmium intoxication. The experimental animals were randomly allocated into 3 experimental groups of 6 rats. The collected blood samples were used to determine hematocrit, hemoglobin concentration, blood erythrocyte count and leukocyte count. The following derived red blood cell parameters were calculated in parallel according to the standard methodology. Between groups 1 and 2 there are no significant differences, a sign that vitamin E exerts an effective protective role. We found a significant increase in the white blood cell count and the neutrophil count in group 3 compared to group 1. Between groups 1 and 2 there are no significant differences, a sign that vitamin E has annihilated the cadmium-induced specific effect. In the case of cadmium poisoned rats, we found a decrease in the number of red blood cells, the hematocrit and the hemoglobin level, but also a significant increase in the number of white blood cells. If rats were treated with cadmium and vitamin E, there were not significant differences from the control group.