Abstract This study aimed to investigate the effects of dietary supplementation with modified-hen-egg-yolk on plasma lipids and lipoprotein profiles in rats. During the four-week-experiment, 64 Wistar rats were divided into four groups of 16 (eight of both sexes), and fed commercial rat food (group C); food containing 70% commercial rat mixture and 30% freshly cooked egg yolk originating from laying hen eggs fed with 3% fish oil (group F); 3% palm olein (group P), or 3% lard (group L). The cooked egg yolk in the rat diet affected the concentrations of plasma total and LDL-cholesterol in males of the P and L groups. Cholesterol and total fat in the diet did not have a hypercholesterolemic effect on their own, but when in combination with fatty acid composition, they could contribute to an increase in plasma total and LDL cholesterol concentrations in rats. HDL-cholesterol was the most resilient plasma lipoprotein of rats to dietary treatments in our experiment. Compared to the control group, the addition of hen egg yolk to the rat diet regardless of its quality, adversely affected the values of HDL-C/TC and HDL-C/LDL-C in both males and females.

The aim of the study was to explore the effect of lactate on insulin-stimulated glucose uptake in rats. Thirty Wistar rats, weighing 250 - 300 g. were arbitrarily divided into one of three groups (n =10): insulin (1 IU/kg) treated group, lactate (80 mg/kg), and insulin plus lactate treated groups. Blood glucose levels were measured in venous samples collected from the tail vein over 3 hour period after insulin or/and lactate administration in 30-minute intervals. To estimate the influence of lactate on insulin blood level, a total of 20 rats were divided into 4 groups (n = 5): saline, insulin, lactate, and insulin plus lactate treated group, respectively. Sixty minutes after the appropriate application of the same doses of insulin, lactate, and lactate plus insulin, as in the previous part of the experiment, plasma insulin and blood glucose levels were determined in blood samples drawn from the abdominal aorta. Lactate in combination with insulin, in comparison to insulin application alone, caused a dramatic increase in plasma insulin level (p<0,001) and more profound hypoglicaemia (p<0,001). The results of this investigation indicate that lactate application significantly increases the rate of glucose uptake from peripheral blood caused by exogenous insulin action. The possible involvement of lactate in the mechanism of enhanced glucose uptake due to insulin action after physical exercise is discussed.

Knowledge of spontaneous aberrations, namely, of their frequency in non-irradiated cells is of paramount importance not only in cytogenetic research, but also in contemporary animal production. The paper deals with research on spontaneously emerged chromosomal aberrations in the peripheral blood lymphocytes in the cattle of 'Busa' breed. To obtain metaphase chromosomes the conventional method of lymphocyte cultivation was used, albeit slightly modified and adapted to the examined animals and the laboratory conditions. The research findings indicate that a certain percent of spontaneously emerged chromosomal aberrations of chromatid type (gap and break) have been found in the peripheral blood lymphocytes in the cattle of 'Busa' breed.