Hematology and stress physiology of juvenile diploid and triploid shortnose sturgeon (Acipenser brevirostrum)

Abstract

This study examined diploid and triploid shortnose sturgeon hematology and stress physiology through the investigation of various characteristics and components of whole blood and blood plasma. Erythrocytic cellular and nuclear length and width were significantly larger in triploids than in diploids. Hematocrit was depressed in triploid sturgeon in comparison to diploids, but total blood hemoglobin content and mean erythrocytic hemoglobin concentration (MEHC) did not differ between ploidies. The mean erythrocytic hemoglobin (MEH) was elevated in proportion to the increase in erythrocyte size. Taken together, these data suggest that triploids and diploids likely have similar oxygen carrying and aerobic capacities. In response to an acute stressor of 15 min chasing, plasma cortisol and glucose levels did not differ between ploidies. Cortisol levels were significantly depressed at 2 h post-stress with an increase back to 0 h post-stress levels at 6 h into recovery, whereas glucose levels did not change during the recovery period. There was a significant interaction between ploidy and time post-stress for blood hemoglobin concentrations, with diploids demonstrating elevated hemoglobin content at 6 h post-stress. Plasma osmolality, chloride ion concentrations and lactate levels were elevated in triploids. Overall, it does not appear that sturgeon have developed an elaborate stress response and the triploid stress response appears to be slightly reduced in comparison to diploids.