Assessment of uptake and processing of different types of yolk proteins during ovarian and embryonic development in Atlantic halibut (Hippoglossus hippoglossus) and European placie (Pleuronectes platessa)
Variable egg quality is one of the remaining bottlenecks in flatfish culture and it is necessary to perform comparative studies between different species, and also spawning performance consistency in individuals. 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 and European plaice, in order to obtain a specialised and reliable tool for selection of broodstock in flatfishes. The current proposal is a follow-up study of work done in 2019 and 2020 (FOTS 19294 and 22921, respectively) to examine consistency in spawning performance of individual females and needs to be extended until 2024 to allow comparisons between the two flatfish species. Accordingly, ovarian samples will be collected via biopsies from mature females who are, based on data obtained from previous reproductive seasons, known to steadily release good and poor quality eggs. Additional egg 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 (sample collection via biposy), 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 and European plaice by discovering the potential impairments in the normal functioning of the multiple vitellogenin system. 10-12 mature female of each species will be sampled once during their reproductive season. 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.
Different stages of oocytes (sample collection via biposy), 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 and European plaice by discovering the potential impairments in the normal functioning of the multiple vitellogenin system. 10-12 mature female of each species will be sampled once during their reproductive season. 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.