THE EFFECT OF AGE AND THE TYPE OF LIQUID FEED ON THE INSULIN AND INSULIN RECEPTOR ISOFORMS mRNA EXPRESSION IN THE JEJUNUM OF NEONATAL CALVES

The objective of the study was to determine the effect of age and the type of the liquid feed on the mRNA expression of insulin and two isoforms of its receptor (IR-A and IR-B) in the jejunum of neonatal calves. Thirty bull calves were randomly allocated to five experimental groups (6 animals per group). Calves from group 1 were slaughtered immediately after allocation to the trial at the age of 5 days. Calves from the group 2, 3 and 4 were fed milk replacer and slaughtered at week intervals (on 12., 19., 26. day of life, respectively). Calves from group 5 were fed whole milk and slaughtered at the 26. day of life. Groups 2, 3, 4 and 5 were offered starter mixture ad libitum during whole study period. Tissues from the jejunum were collected subsequently to slaughter. Expression of mRNA of insulin and insulin receptor isoforms were evaluated using the semi-quantitative RT-PCR method. Ins mRNA expression increased linearly together with calves age whereas IR-B mRNA expression showed the quadratic trend of changes. Type of liquid feed had no effect on the expression of investigated genes in jejunum of neonatal calves.