Production of live larvae following in vitro maturation of zebrafish oocytes

Abstract

This study aimed to assess the effects of carp pituitary extract (CPE), follicle stimulating hormone (FSH) and luteinizing hormone (LH) on zebrafish oocyte maturation and the ability of these mature oocytes to be fertilized and developed until hatching. Stage III follicles were matured in eight treatments: five concentrations of CPE (16, 32, 48, 64 and 80 μg/mL), one of FSH (0.5 μg/mL), one of LH (0.5 μg/mL), or one combination of FSH (0.5 μg/mL) and LH (0.5 μg/mL). Maturation rates in CPE treatments were 12.8% (16 μg/mL), 24.8% (32 μg/mL), 27.0% (48 μg/mL), 22.7% (64 μg/mL) and 9.6% (80 μg/mL); in FSH was 15.7% (0.5 μg/mL), in LH was 31.8% (0.5 μg/mL) and in FSH (0.5 μg/mL) combined with LH (0.5 μg/mL) it was 50.4%. In vitro fertilization was performed in all treatments; however, only the treatment combining FSH and LH resulted in fertilized oocytes. After maturation using FSH combined with LH, the cleavage rate was 33.3% and hatching rate of live larvae was 20.0%. These results showed that FSH combined with LH was effective in IVM of zebrafish oocyte.

Chilling sensitivity of Steindachneridion parahybae (Siluriformes: Pimelodidae) oocytes in different cryoprotectants

“…So, this stage of development could be better for cryopreservation studies, but for the fertilization in vitro maturation is necessary, although this technique has not been resolved yet. In this context, the first positive results were showed by Silva et al. (2018) using different hormones for vitelogenic oocytes (Stage III) maturation in zebrafish, Danio rerio , which is very important for future studies in this way.…”

Improving CRISPR/Cas9 mutagenesis efficiency by delaying the early development of zebrafish embryos

“…However, although the method by Xie et al significantly increased the mutagenesis efficiency, it also resulted in mosaic animals, perhaps due to a short incubation time (30 min) between the injection and in vitro fertilization and the use of Cas9 mRNA instead of a protein 10 . As reported by Xie et al, and by many others, the choice of an appropriate medium is critical for the storage of the oocytes and the success for the in vitro fertilization 12,[15][16][17] . Here, we used the ovarian fluid form Rainbow trout as a novel preservation medium for zebrafish oocytes.…”

“…These rather low survival rates even in the control group are not exceptional among the in vitro fertilization studies in zebrafish and mainly result from the varying quality of oocytes and sperm, i.e. parameters which based on the current knowledge are difficult to control 10,15,16 . Our results therefore also highlight the need for an optimized in vitro fertilization protocol for zebrafish.…”

Maturation Inducing Hormones in teleosts: Are progestogens always the first to be nominated?

“…The choice of the most reliable culture medium has been proven to be highly dependent on the osmolality of the medium (Seki et al, 2008). Indeed, the medium should be isosmotic (Silva et al, 2018). In a recent study performed on sturgeon, it was revealed that the percentage of oocytes that were successfully ovulated in vitro increased after the concentration of sodium bicarbonate in the culture medium was decreased.…”