Triploidy in white sturgeon (Acipenser transmontanus): Effects of acute stress and warm acclimation on physiological performance

Abstract

Previous studies have demonstrated reduced performance in triploid fish when reared under suboptimal conditions, which may be the result of a higher susceptibility to stressors when compared to diploids. The goal of this project was to investigate differences in the capacity of diploid (8 N) and triploid (12 N) white sturgeon, Acipenser transmontanus, to respond to both warm acclimation (6-weeks of acclimation to either 18 or 22°C) and a subsequent acute stress (10-min low water stress). Following the 6-week acclimation, fish were sampled either before or following an acute low water stress. Bioindices of the primary and secondary stress response, hematology and cellular metabolic status were measured. We also sought to determine if time to peak cortisol levels were similar between diploid and triploid sturgeon after exposure to a severe acute stressor (netting stress). While both ploidies had similar primary and secondary responses to acute stress, both with and without warm acclimation, warm acclimation impacted the ability of diploid and triploid white sturgeon to mount a typical stress response to an acute stressor. In response to warm acclimation, triploids exhibited little change in branchial lactate dehydrogenase activity, while diploids increased activity. After exposure to an acute water reduction stress, diploids increased citrate synthase activity, yet triploids showed a decrease in activity. Differences in metabolic enzyme activity in response to warm acclimation and acute stress suggest triploid white sturgeon may have a reduced cellular metabolic capacity under chronic and acute stress, which may impact performance of triploid sturgeon in suboptimal conditions.

Seasonal Temperature Fluctuations Differently Affect the Immune and Biochemical Parameters of Diploid and Triploid Oncorhynchus mykiss Cage-Cultured in Temperate Latitudes

“…A similar response was observed due to changes in other environmental conditions, such as rearing in saltwater [37]. Likewise, impaired development has been reported in other induced triploid fish, such as Acipenser transmontanus [10] and Salmo salar [8].…”

“…The Ec was also higher in diploid animals at lower temperatures (9 • C). The differences in the metabolic enzyme activity of diploid and triploid Acipenses transmontanus in response to warm acclimation also indicated the lower cellular metabolic capacity of triploid individuals under stress conditions [10]. Furthermore, higher metabolic rates were observed for triploid Salmo salar and Salvelinus fontinalis at lower temperatures (12 • C), along with the inversion of these metabolic tendencies at higher temperatures (18 and 15 • C, respectively) [55].…”

“…However, their lower growth and survival in warmer waters were quickly noted [6]. There is also rising evidence of the increased costs of triploidy, due to triploids' higher mortality rates and underperformance in suboptimal conditions, namely suboptimal temperatures, when compared to diploids [7][8][9][10][11]. The better survival rates of triploid trout were only observed in fish reared for recreational purposes at low densities [12].…”

The Innate Immune Response of Atlantic Salmon (Salmo salar) Is Not Negatively Affected by High Temperature and Moderate Hypoxia

“…There is little information on the effect of the rate of temperature change (increase) on fish immune responses (15), and although the current study did not examine this issue, we suspect that the non-deleterious effect of long-term exposure to high temperature may, in part, be related to circulating cortisol levels in fish exposed to long-term vs. acute increases in temperature. Plasma cortisol has been shown to increase sharply after an acute exposure to high temperature in fish (109)(110)(111)(112), while chronic exposure to high temperature revealed few impacts on the stress physiology/cortisol levels in Atlantic salmon (113) or other teleost species (25,34,114,115). In fact, we measured resting plasma cortisol levels in a very similar experiment to this one [see Experiment # 2 in Gamperl et al (37)] and they did not become elevated until the fish experienced a temperature of 22 • C [Zanuzzo et al (in preparation)].…”

Hybridization of Russian Sturgeon (Acipenser gueldenstaedtii, Brandt and Ratzeberg, 1833) and American Paddlefish (Polyodon spathula, Walbaum 1792) and Evaluation of Their Progeny

“…Havelka et al [ 20 ] described the spontaneous duplication of the maternal chromosome set in Siberian sturgeon of different ploidy caused by either premeiotic endomitosis or the retention of the second polar body. Many other studies [ 51 , 52 , 53 ] have stated the retention that the second polar body can lead to polyploidization. The different ratios of triploid/pentaploid individuals among the parent combinations in our study also supported this hypothesis.…”