Project number: 2017-220
Project Status:
Completed
Budget expenditure: $85,422.00
Principal Investigator: Jan Strugnell
Organisation: James Cook University (JCU)
Project start/end date: 3 Jun 2018 - 30 Dec 2020
Contact:
FRDC

Need

There is a need in the abalone industry to improve production animals. However, abalone are relatively slow growing animals and take several years to reach harvest size. This means that during the establishment of foundation broodstock populations it may be several years before the relative genetic merit of each of the broodstock can be determined and the first selection decisions made. During this time, the hatchery manager will have to blindly spawn broodstock to stock the farm, often with broodstock possessing poor gEBV and that produce slow growing animals. This comes at the additional cost of not being able to cull poor performing broodstock early in the establishment of the population and replacing them with new broodstock.

Through measuring the family performance (and thus broodstock gEBV) of these cellular traits in larvae and comparing broodstock gEBV with those derived from progeny at harvest, a high genetic correlation would indicate that it is possible to predict genetic merit using these cellular traits. Studies have shown that the ratio between RNA and DNA in cells has a high heritability (necessary for the traits to have predictive power) and that it can be used to accurately predict the gEBV of barramundi broodstock without the necessity of rearing progeny all the way through to harvest (genetic correlation >0.8). Therefore, using RNA/DNA as the trait to measure in barramundi larvae it is now possible to establish high performing broodstock foundation populations via mass-spawning broodstock, estimating their genetic merit based on larvae RNA/DNA, and then eliminating those broodstock with inferior gEBV from the breeding population.

Several Australian barramundi hatcheries now apply this technique to assist in the selection of broodstock. This method is as yet untested in abalone, but if successful, has great potential in helping screen broodstock. This project will test the efficacy of this early prediction method in abalone. The impact of this early detection method would be to save costs by assisting in the selection of superior broodstock individuals which would produce faster growing offspring. Currently new broodstock animals are unevaluated with regard to their genetic merit.

Objectives

1. Assess the utility of RNA/DNA ratio as a method for early prediction of high performing abalone broodstock

Final report

ISBN: 978-0-6454198-2-5
Authors: Phoebe Arbon Dean Jerry Jan M. Strugnell
Final Report • 2022-05-01 • 2.99 MB
2017-220 DLD.pdf

Summary

This report provides an assessment of the utility of RNA/DNA ratio as a method for early prediction of high performing abalone broodstock. The study was carried out on farmed Greenlip Abalone (Haliotis laevigata) whereby families were produced and resulting progeny were reared using commercial protocols. RNA/DNA ratio and shell length were measured in post larvae, and shell length, shell width and total weight were measured in juveniles and harvest sized individuals. All individuals were genotyped, parentage was assigned and heritability and genetic correlation of traits was calculated. Analyses in post-larvae and juveniles could not estimate heritability of traits including RNA:DNA and shell length indicating that the additive genetic variance component of these traits were unable to be separated from non-genetic components (e.g., environment) at early production stages (i.e. post-larvae and juveniles). This indicates that further grow out would be required to assess broodstock quality for use in breeding programs. The project was carried out between 2019-2022 by Phoebe Arbon, under the supervision of Prof. Jan Strugnell and Prof. Dean Jerry, based within the Department of Aquaculture at James Cook University, Australia.
There was no detectible heritability of post-larval traits including RNA:DNA and shell length. Therefore, the genetic potential of broodstock was not able to be predicted using progeny performance at the earlier life stages (i.e., post larvae or juveniles). This is likely to be due to a strong influence of environmental factors at early life stages. At harvest size, however, all production traits (shell length, width and animal weight) had a significant additive genetic component. Therefore, realisation of a genetic effect only occurred in the later harvest stage of production and was masked at the earlier stages of production (i.e., post-larvae and juvenile stages).
The implications of this study are that grow out of progeny to harvest size (or close to) is currently still required to determine the genetic merit of abalone broodstock in selective breeding programs. Furthermore, future studies following the same individuals in a cohort through time are required to better understand the result that the genetic effect is only realised at the harvest stage. This work is required to better inform current grading practices. Furthermore, a moderate heritability for growth traits was detected and so there is also potential for farmers to improve growth of stock through selection.

Related research

Industry
Industry
Industry
PROJECT NUMBER • 2021-076
PROJECT STATUS:
COMPLETED

Abalone Viral Ganglioneuritis (AVG) R&D Needs Workshop

1. Conduct an analysis of past research on AVG, create a plain English summary and identify knowledge and research gaps that can be evaluated nationally by key stakeholders
ORGANISATION:
Abalone Council Victoria Inc (ACVI)