Changes in juvenile sturgeon erythrocytes across age classes reflects evolutionary development

Abstract

Erythrocytes are important for gas transport and exchange in animals and play an important role in maintaining normal functions of the body. The purpose of this study was to observe the changes in erythrocyte morphology during the development of juvenile sturgeon (Acipenser baeri ♀×Acipenser schrenckii ♂ hybrid F1) and to describe the relationship between erythrocyte morphology and development. We compared the erythrocyte morphology of juvenile sturgeon in three developmental stages. The results showed that the blood index of the sturgeon in different age classes was significantly different. The erythrocyte volume in the blood became smaller and the shape of erythrocytes changed from circular to elliptical. With the increase in age, the number of selfdividing erythrocytes, and the types and numbers of organelles in the erythrocytes, decreased. The results demonstrated that the morphology and the internal structure of erythrocytes develop to be more beneficial for gas transport reflecting the needs for juvenile sturgeon maintenance and environmental changes.

Comparing the incidence of spontaneous autopolyploidy in wild and hatchery Lake Sturgeon

“…However, previous research has established a direct relationship between body size and cell volume in vertebrates, consistent with the negative correlation that we observed (Gregory 2001;Lahnsteiner 2021). Age-related differences have also been investigated, with older individuals having significantly smaller erythrocytes (Nikinmaa 2020;Yang et al 2021). Unfortunately, in those studies, body size changes were considered akin to aging such that it was unclear whether size, age, or some combination of the two was causing these cellular changes.…”

“…Total length and wet mass were both weakly correlated with the changes in MNV over time; like the analysis between populations, the MNV decreased as the individuals grew. This complements recent research, which found that older juvenile sturgeon (40-540 days) had smaller and more numerous erythrocytes (Yang et al 2021). Although statistically significant, the magnitude of change in average MNV within this population over time was small (52.9-55.7 fL).…”

“…As RBCs perform key functions in respiratory gas exchange, the availability of oxygen in the environment has been shown to regulate RBC size (Hardie and Hebert 2003). Demand for oxygen is parallel to growth in aerobic animals such that larger individuals require more oxygen (Yang et al 2021). To accommodate a growing demand for oxygen, circulating RBCs become smaller and more numerous, allowing higher rates of oxygen diffusion (Yang et al 2021).…”

“…Demand for oxygen is parallel to growth in aerobic animals such that larger individuals require more oxygen (Yang et al 2021). To accommodate a growing demand for oxygen, circulating RBCs become smaller and more numerous, allowing higher rates of oxygen diffusion (Yang et al 2021). Therefore, erythrocyte morphometry (i.e., size) undergoes changes over an organism's development such that significant differences in nucleus volume have been observed within juvenile development (40-540 days) and between the juvenile (1 year) and adult (6 years) stages of fish (Lahnsteiner 2021;Yang et al 2021).…”

“…To accommodate a growing demand for oxygen, circulating RBCs become smaller and more numerous, allowing higher rates of oxygen diffusion (Yang et al 2021). Therefore, erythrocyte morphometry (i.e., size) undergoes changes over an organism's development such that significant differences in nucleus volume have been observed within juvenile development (40-540 days) and between the juvenile (1 year) and adult (6 years) stages of fish (Lahnsteiner 2021;Yang et al 2021). Oxygen availability in aquatic ectotherms is further regulated by environmental temperature and metabolic activity such that their influence also moderates RBC size (Hardie and Hebert 2003).…”