Changes in lipid metabolism during last month of pregnancy and first two months of lactation in primiparous cows-analysis of apolipoprotein expression pattern and changes in concentration of total cholesterol, HDL, LDL, triglycerides

The final weeks of pregnancy and period of increasing lactation abound with adaptive changes in the intensity of metabolic processes. Maintaining the homeostasis of an organism in prepartum and postpartum periods is the key condition in maintaining the health of the mother and the fetus/calf. The aim of the study was to analyze physiological changes in lipid metabolism in cows during the last month of first pregnancy and in the first two months of lactation, based on the expression of identified apolipoproteins and changes in selected parameters of the lipid metabolism in peripheral blood plasma. Statistically significant changes in the expression of identified apolipoproteins were observed for apolipoprotein A-1 precursor, apolipoprotein A-IV precursor, apolipoprotein E precursor and apolipoprotein J precursor. The lowest expression of the apolipoproteins was noted around parturition and higher expression was observed during the final weeks of pregnancy and during lactation. Tendencies of changes in the concentration of total cholesterol, HDL and LDL were similar in blood plasma from analyzed cows - in the last month of pregnancy a decrease was observed and subsequently an increase in the first two months of lactation was noted. In contrast to abrupt changes observed for total cholesterol, HDL and LDL, changes in concentration of triglycerides were not that extensive and during lactation this parameter was rather stable. Evaluation of changes in the analyzed parameters may contribute to a better understanding of the changes in lipid metabolism occurring in the body of pregnant and lactating young cows

Feeding milk replacer instead of whole milk affects blood plasma proteome and lipid profile in preruminant calves

The study was undertaken to determine the effect of feeding milk or milk-replacer on the blood plasma proteome and lipid profile in calves during the second week of life. Feeding milk-replacer significantly decreased the expression of plasma apoA-I. Age of calves affected apoA-I expression, which was higher on the 8th than on the 11th and 14th day of life. A significant effect of interaction between diet and age was also observed. The expression of apoA-IV, was significantly affected by diet and was lower in calves fed milk replacer. Expression of this protein was significantly lower at the 8th day of life and was up-regulated in the calves fed milk-replacer at the second week of life. Calves fed milk-replacer had greater expression of haptoglobin, which differed significantly between days of blood sampling, being higher on the 8th than on the11th and 14th day. The interactive effect of diet and age affected haptoglobin expression, which was successively down-regulated in calves fed milk replacer. Diet had a significant effect on the plasma lipid profile. Animals fed milk had a greater concentration of TC, HDLC and LDLC. The composition of milk-replacer, especially fat source, is probably the main factor that affects expression of proteins involved in cholesterol metabolism and level of components of lipid profile in calves fed formula. We claim that the initially increased level of haptoglobin, followed by its decrease during the second week of life in calves fed milk-replacer may indicate the presence of short-term stress induced by changes in the feeding system

Blood plasma protein and lipid profile changes in calves during the first week of life

The present study was undertaken to determine blood plasma protein and lipid profile changes in healthy Polish Holstein-Fresian calves of Black-and-White variety. Blood was drawn immediately after birth, before first colostrum intake and at the 3rd, 6th, 12th, 24th, 36th, 48th and 72nd hour of life. Subsequent four blood samples were collected at 24 hour intervals until the 7th day of life. Plasma proteins within the isoelectric point ranging from 3.0 to 10.0 were separated using high resolution two-dimensional electrophoresis. Among the 74 protein spots detected and analyzed, 16 were significantly altered during the first week of life. Differentially expressed spots were excised from the gels and subjected to peptide mass fingerprinting using MALDI-TOF MS. In total, 12 spots were successfully identified, which correspond to three proteins, namely: apolipoprotein A-I, apolipoprotein A-IV and fibrinogen gamma-B chain. A gradual increase in plasma triglyceride, total cholesterol, HDL and LDL cholesterol values was shown during the first seven days of calves life. The lowest concentration of these indicators were observed at birth and was followed by a rapid increase during the first week of postnatal life. These changes appear to be related to the transition in energy sources, from a maternal nutrient supply comprising mainly carbohydrates and amino acids to a diet which was rich in fat – colostrum and milk. This was reflected by the intense up-regulation of plasma proteins related with lipid transport and lipoprotein metabolism during the first week of life

Mapping of polar fox renal cortex proteins using two-dimensional gel electrophoresis and mass spectrometry – a preliminary study

The aim of the present study was to establish protein map of polar fox (Alopex lagopus) renal cortex. Kidney cortex proteins of isoelectric point ranging from 3 to 10 were analysed using two-dimensional electrophoresis and MALDI-TOF mass spectrometry. Sixteen protein spots corresponding to thirteen different gene products were identified. These proteins were divided into following groups: lipid and fatty acid metabolism, amino acid metabolism, energetic pathways, regulatory proteins, transport proteins and structural proteins. This is the first attempt to create reproducible 2-D map, of renal cortex proteins characteristic for polar foxes, used as animal model for carnivores. It is worth emphasizing that the results of this study may broaden currently available protein databases