Anesthetic protocol for microinjection-related handling of Siberian sturgeon (Acipenser baerii; Acipenseriformes) prolarvae

Abstract

An anesthetic protocol was optimized for microinjection-related handling of Siberian sturgeon (Acipenser baerii; Acipenseriformes) prolarvae, an extant primitive fish species commonly grown in aquaculture. Comparative examinations of three selected anesthetics (clove oil, lidocaine, and MS-222) with a dosage regime of 50, 100, 200, and 400 mg/L indicated that MS-222 was the most efficient agent for Siberian sturgeon prolarvae, as evidenced by the fast induction of anesthesia with quick and uniform recovery. Meanwhile, clove oil should be avoided, due to prolonged recovery times varying widely between individuals. None of the tested anesthetics significantly affected prolarval viability at any of the dosage regimes tested in this study. Based on an analysis of the duration of an unconscious state in air, we recommend a dose of 200 mg/L MS-222 for microinjection. Recovery time after use of this dose was influenced by the prolarval age and the development of gills, in which prolarvae older than 3 days after hatching required longer recovery times than did younger prolarvae. Post-recovery behavioral assessment showed no apparent difference between MS-222-anesthetized and non-anesthetized prolarvae in their swimming behavior and phototactic responses. Applicability of currently developed anesthetic protocol using MS-222 in larval microinjection was demonstrated with the injection of a visible dye to the anesthetized prolarvae, followed by the analysis of post-recovery viability. Taken together, the present anesthetic protocol based on 200 mg/L of MS-222 could provide researchers with practical usefulness with good safety margins for the micromanipulation and other related handlings of Siberian sturgeon prolarvae.

Superoxide Dismutase Multigene Family from a Primitive Chondrostean Sturgeon, Acipenser baerii: Molecular Characterization, Evolution, and Antioxidant Defense during Development and Pathogen Infection

“…During the early ontogenetic period (1 to 3 dph), showing an initial increase in the expression of AbSOD1 (and AbSOD2), A. baerii prelarvae change their behavior from drifting movement to active pelagic swimming at the upper water column, with dramatic increases in swimming distance and speed. Furthermore, prelarvae during this period have the strongest positive phototaxis, making them continuously pursue light sources [ 61 ]. Undoubtedly, such energy-intensive behavioral changes are accompanied by an increased respiration rate and parallel accumulation of oxygen radicals.…”

“…However, one plausible explanation is that the continuous increase in this isoform might be partially related to neovascularization and increased circulation activities in developed blood vessels, rather than to the defense against the overall oxidative stress caused by high-oxygen-consuming exercise. Previous studies have indicated that A. baerii hatchlings usually continue vasculogenesis/angiogenesis during the prelarval period, especially associated with the active development of the external gill filaments and branchial circulation [ 39 , 40 , 42 , 61 ].…”

“…In Vivo Immunostimulatory Challenges 2.6.1. Microinjection of LPS or Microbial Pathogens into Prelarvae To examine whether hatched prelarvae were able to modulate AbSOD mRNA expression in response to endotoxins or pathogen infection, which would potentially provoke ROS generation, we microinjected prelarvae with lipopolysaccharides (LPS; Escherichia coli; 0111: B4; Sigma-Aldrich, St. Louis, MO, USA) or Aeromonas hydrophila (Gram-negative; KCTC 2358); the conditions for the microinjection and anesthesia of prelarvae were as described in our previous work [61]. Briefly, 1-day-old prelarvae (n = 48, average body weight (BW) = 14.3 ± 0.42 mg) were anesthetized with 200 ppm of MS-222 (Sigma-Aldrich, USA), which was microinjected along with 20 nL of LPS at 20, 40, and 80 µg/g BW or 1 × 10 3 CFU/g BW of A. hydrophila suspended in phosphate-buffered saline (PBS, pH 7.4) into the border region between the prelarval body and yolk extension.…”

Geometric morphometric analysis of body shape and size variations in hatchery-reared larvae of a tropical damsel fish, Dascyllus carneus Fischer, 1885

“…Test species and procedure A total of 260 number of larvae of D. carneus were used for the entire study. The larvae were anesthetized using MS222 before the study procedures [116,117] . Different larval stages and juveniles stages were photographed appropriately.…”

Behavioral characteristics of a chondrostean sturgeon species Acipenser baerii prelarvae in response to different environmental light intensities in a diel photoperiodic cycle

“…In hatcheries, sturgeon prelarvae are generally expected to experience substantial changes of light intensities according to the diel photoperiodicity, suggesting that the practical guide for prelarval nursery should essentially consider the photobehavior of prelarvae. Furthermore, the comprehensive guideline of behavioral ontogeny may also be a fundamental basis for various research investigations with prelarvae such as ontogenetic gene expression assay and examination of physiological alterations, because all those investigations need the information on the standard behavioral phenotype of experimental specimens used (Song et al, 2016;Kim and Nam, 2018;Kim et al, 2019c).…”