Forsøksdyr: Assessment of uptake and processing of different types of yolk proteins during ovarian and embryonic development in Atlantic halibut (Hippoglossus hippoglossus).

Godkjenningsdato 20.02.2020

Godkjenningsperiode 20.02.2020-20.02.2021

The specific purpose of this study is to assess the uptake, deposition and processing of multiple forms of the yolk protein precursor vitellogenin (Vtg) in Atlantic halibut, in order to obtain a specialised and reliable tool for selection of broodstock.For this purpose, ovarian samples will be collected from mature females who are, based on data obtained from previous reproductive seasons, known to steadily release good and poor quality eggs . The current proposal is a follow-up study of work done in 2019 (FOTS 19294), to examine consistency in spawning performance of individual females. Samples will be taken during normal routine checks for ovulation and stripping of eggs. The team performing sampling have many years of experience in broodstock management, stripping of eggs and taking ovarian samples.Therefore, additional fish stress during sampling is expected to be minimal.
Different stages of oocytes, fertilized eggs and late embryos,and yolk sac larvae will be analysed for quantification of different types of Vtgs and their yolk protein domains. The study will allow better understanding on the specific timing of deposition and utilization of different types of yolk proteins in developing oocytes and offspring, and the mechanisms involved in this process. Results will assist in determining the roots of poor quality eggs in Atlantic halibut by discovering the potential impairments in the normal functioning of the multiple vitellogenin system. 8-10 mature female Atlantic halibut will be sampled once during their reproductive season. Variable egg quality is one of the remaining bottlenecks in halibut culture and it is necessary to perform species-specific studies, and also spawning performance consistency in individuals. The number of individuals is held as low as possible for valid statistic calculations and the aim is to improve spawning performance in female halibut, thereby refining management routines.