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To determine the changes in blood chemistry associated with sequential transfer of summer flounder Paralichthys dentatus (320–480 g), 300 hatchery-reared fish were moved to three different environmental conditions during a 20-d period. Fish were transferred in progression from a recirculating seawater system (22 ppt, 22.5 C) to a flow-thru seawater system (31 ppt, 20.0 C), to three small coastal net pens (33 ppt, 15.5 C), and finally to a large open ocean net pen (33 ppt, 16.0 C). For this study, eight random fish were captured at each progressive step (environmental condition), anesthetized (MS222), and bled from the caudal vein (2 mL). Transferred flounder were bled every 12 h for 48 h to collect plasma cortisol and glucose samples. Fish were bled 24 h after transport and every 3 d thereafter for osmolarity, hematocrit, hemoglobin concentration, mean corpuscular hemoglobin content, glucose, cortisol, and the electrolytes Cl- Na+ , K+ and Ca+ . The most significant perturbations to blood chemistry (P < 0.05) occurred within 24 h of initial transfer from the recirculating to flow-thru seawater systems, suggesting an osmoregulatory rather than handling or transfer related stress. Osmolarity, electrolyte, and hematological parameters fluctuated and then recovered to stable levels by day 8 in the flow-thru seawater system. However, unlike the initial transfer, successive movement to the coastal and then the open ocean net pens produced transient increases in both plasma cortisol and glucose levels, suggesting a high level of stress associated with extended flounder handling and transfer. 相似文献
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Laura Jay Williams Matthew D. Campbell Paul C. W. Tsang James A. Sulikowski 《Fish physiology and biochemistry》2013,39(5):1089-1099
In the current study, plasma steroid hormones were used to assess the individual variability of Leucoraja erinacea over the course of 12 months, in hopes of further defining its reproductive cycle. No statistical differences in hormone concentrations were observed between the isolated and non-isolated female skates. Monthly E2 concentrations ranged from 1,430 pg ml?1 in August to 3,940 pg ml?1 in March, indicating the presence of mature ovarian follicles and supporting the conclusions from previous studies that L. erinacea is capable of reproducing year-round. Concentrations of E2 were significantly elevated or depressed during some months (February, March, June, July, August, and September) of the year, suggesting that reproductive activity may vary over the annual cycle. Even though monthly P4 concentrations were highly variable, ranging from 82 pg ml?1 in November to 816 pg ml?1 in September, no significant reproductive peaks were observed. In addition, a persistently large variation in E2 and P4 concentrations, indicative of reproductive asynchrony within (mean CV 62 % and CV 69 %, respectively) and between (mean range CV 78 and 125 %, respectively) individual skates, was observed throughout the study. Collectively, the continually high E2 concentrations and variability in both hormones observed in the current study are indicative of an oviparous species that reproduces actively throughout the year. However, the weekly sampling frequency revealed that plasma E2 concentrations, not P4, were more useful to assess reproductive status in asynchronous continuously breeding oviparous elasmobranchs. 相似文献
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