Cholesterol-loaded cyclodextrin improves motility and survival of cryopreserved zebrafish (Danio rerio) sperm.

We studied the impact of modulating cholesterol levels in zebrafish sperm plasma membranes using cholesterol-loaded methyl-ß-cyclodextrin (CLC) and unloaded methyl-ß-cyclodextrin (MßC). Zebrafish sperm were treated with these substances before cryopreservation, and post-thaw sperm motility and in vitro fertilization (IVF) rates were compared between treated and untreated samples. Our findings indicate that adding cholesterol to sperm membranes increases post-thaw motility, motile cell count, and motile cell survival within a 0.5-4.0 mg per 1.2 × 108 cell concentration range. Conversely, depleting cholesterol using MßC at 1.0 and 2.0 mg per 1.2 × 108 cells reduced these parameters. On average, all CLC-treated sperm samples produced a 15 % higher IVF rate compared to untreated sperm. Including CLC in the extender before cryopreservation is beneficial for post-thaw sperm quantity and quality in zebrafish.

Tenth Aquatic Models of Human Disease Conference 2022 Workshop Report: Aquatics Nutrition and Reference Diet Development.

Progress in biomedical research requires rigorous studies and reproducible outcomes. However, despite recent achievements, standard reference diets (SRDs) for aquatic model organisms, vital for supporting scientific rigor and reproducibility, are yet to be adopted. At this workshop, we presented findings from a 7-month diet test study, tightly coordinated and conducted across three aquatic research facilities: Zebrafish International Resource Center (ZIRC), Kent and Sharpton laboratories (Oregon State University), and Xiphophorus Genetic Stock Center (XGSC, Texas State University). We compared the impact of two commercial diets and a suggested zebrafish SRD on general fish husbandry, microbiome composition, and health in three fish species (zebrafish, Xiphophorus, and Medaka), and three zebrafish wild-type strains. We reported outcomes, gathered community feedback, and addressed the aquatic research community's need for SRD development. Discussions underscored the influence of diet on aquatic research variability, emphasizing the need for SRDs to control cross-experiment and cross-laboratory reproducibility. Species-specific reference diets are essential for model organism health and consistent research outcomes.