Characterising the metabolic differences related to growth variation in farmed Haliotis midae

Abstract

The South African abalone farming industry is entirely based on Haliotis midae, which has been commercially cultured with great success the last 20 years. Even though abalone are cultivated under identical farming conditions, originating from homogenous genetic stocks, variation is experienced in individual abalone growth rates, justifying further research into the mechanisms related to these growth differences. Insights into the biochemical processes of abalone would help to identify the various metabolic factors related to varied abalone growth rates. Metabolomics, aims to investigate the metabolism holistically, and is considered a powerful tool for better elucidation of observed phenotypical changes. A metabolomics approach including the use of untargeted gas chromatography-time of flight spectrometry, semi-targeted liquid chromatography-quadrupole time of flight mass spectrometry and targeted liquid chromatography-tandem mass spectrometry were used to indicate and better describe the metabolic variation associated with slow and fast growing abalone. The results obtained by metabolomics analysis of H. midae adductor muscle samples showed that faster growing individuals utilise energy pathways and reserves (via elevated insulin production) in such a way that they promote protein synthesis. In contrast the metabolic profile of slow growing individuals supports protein catabolism, where energy allocation for breakdown of metabolic products has priority over mechanisms utilised for abalone growth. Overall these results sets the stage for future work highlighting metabolic pathways which should be investigated in a qualitative manner ensuring reference values which can furthermore be monitored to assist with abalone growth predictions.