[The size and volume of the kidneys in nutria during postnatal ontogenesis]

Kidneye size and volume, absolute and relative mass, and tissue density was determined in 50 male and female nutria of different age groups (1 day, 2, 4, 5, 7.5 months and 1 year). It was found that in females the relative mass of the kidneys decreased with age, while in males this tendency remained only until the age of 7.5 months. In females from 1 day up to 1 year, the mass and the volume of the right kidney increased 11.44 and 11.25 times, its length and width - increased 2.16 and 2.59 times and its thickness - 2.07 times. In the left kidney, the corresponding indicators increased 11.69, 11.04, 2.14, 2.65 and 2.01 times. In males, from 1 day up to 1 year, the mass and the volume of the right kidney increases 19.49 and 16. 14 times, the length and the width increased 2.69 and 3.11 times and its thickness - 2.38 times. In the left kidney, the corresponding indicators increased 18.52, 16.83, 2.56, 2.98 and 2.72 times. The greatest increase in the indicators studied of the kidneys in female and male nutria took place from birth up to the age of 2 months. It was found that the density of the kidney tissue was the highest at 4.5 months. In the left and right kidneys in female nutria, its value varied from 1.09+/-0,03 to 1.12+/-0.02 g/cm3 respectively, while in the males it changed from 1,04+/-0.01 to 1.08+/-0.02 g/cm3.