Investigation of some nucleoli traits in interphase leukocytes of two rabbit breeds and their hybrid

Abstract

Aim. The aim was to study the differences in three traits of nucleoli in interphase leukocytes of two rab- bit breeds and a hybrid thereof. Methods. Doe rabbits, 4-month -old, from Ukrainian breed Poltavske Sriblo (n = 30), Californian (n = 25), and their hybrid (n = 21) were used in the experiment. The nucleoli in intact blood leukocytes were stained using silver staining according to Howell and Black (1980). Stained cells were observed, and their nucleoli counted in light microscopy at 10×100 oil immersion magnification. 200 leukocytes from each animal were analyzed. The activity of nucleoli was evaluated by the following parameters: the aver- age number of nucleoli in the nucleus (nNO), the total area of nucleoli in the nucleus (ΣSNO, mcm 2), the share of nucleolus area in the lymphocyte nucleus area (shΣS NO, %). Statistical analysis was conducted using the STATISTICA software package (2020). Results. The average number of nucleoli per cell varied from – 1.70 ± 0.08 in Californian rabbits to 5.90 ± 0.29 in hybrid animals. A statistically significant difference (p < 0.05) was found between the experimental groups of purebred and hybrid rabbits. The variation coefficient for the index of the average number of nucleoli per cell was on the average level of variability: 20.58 % for the rabbits of Poltavske sriblo breed, 19.50 % for Californian rabbits, and 16.49 % for hybrid ones. The total area of nucleoli in the cells of all the investigated animals varied from 5 μm2 in one Californian rabbit to 12 μm2 in animals of hybrid origin. The share of the nucleolus area in the nucleus area for rabbits of Poltavske sriblo, Californian, and hybrid breeds was 26.10 ± 1.80 %, 24.30 ± 1.62 and 29.40 ± 2.50, respectively. Conclusions. Polymorphism was observed for three nucleolar parameters after silver staining of interphase leukocytes of rabbits of Poltavske sriblo, Californian breed and their hybrid. This concerned 1) the average number of nucleoli (p < 0.05); 2) the total area of nucleoli (p < 0.05); 3) the average share of the nucleolar area in the nucleus area (p < 0.05). The results of our comparative analysis of the investigated nucleolar activity parameters suggest a higher activity of nucleoli in the animals of hybrid origin. In the future, the results of such studies may be used to assess the potential ability of animals to implement productive traits.