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Abalone is currently considered South Africa's most successfully produced aquaculture export product, with a 76% share of the total value generated by the aquaculture sector. A major risk factor for this sector is slow growth rates experienced during farming. Abalone feeds are often supplemented with amino acids in an attempt to enhance abalone growth. This is a first investigation of the effect of added proline to standard abalone feed, on the metabolite profile of slow‐growing abalone. A targeted liquid chromatography tandem mass spectrometry metabolomics research approach was followed to recognise the metabolic response of abalone showing slower growth performance. The addition of proline to the standard abalone diet was found to serve as a substrate for amino acid catabolism in slower growing abalone, by means of proline breakdown to assist with energy production via the tricarboxylic acid cycle. Other amino acids and urea cycle intermediates, that is, arginine, asparagine, ornithine and creatine further support energy production via the action of protein catabolism in slow‐growing abalone. Additionally, the importance of understanding how abalone respond metabolically to modified feed highlights the use of metabolomics to answer abalone aquaculture farming questions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Worldwide, there are approximately 100 Haliotis species, more commonly known as abalone or ‘Paua’ in New Zealand, ‘Venus's‐ears’ in Greece, ‘Awabi’ in Japan, ‘Perlemoen’ in South Africa and ‘Ormers’ in Europe. Regardless of what they are called in any part of the world, a high monetary value is coupled to this animal, because it is largely considered a seafood delicacy. Subsequently, a great deal of research primarily focused on improving the health and growth rates of abalone were carried out to maximise productivity of the commercial farming efforts in various countries. In this review, we comprehensively describe the most recent available scientific literature on abalone biology, and those aspects related to the growth of this organism; more specifically, those factors related to the uptake and breakdown of metabolic products which ensures long‐term growth. We subsequently discuss this in terms of basic animal design, farming outcomes, feeding, cellular growth mechanisms and the unique metabolic processes that exist in these species. Using this information and the knowledge of the metabolic processes in other organisms, we additionally make a number of new hypotheses regarding how these metabolic processes may function in terms of abalone growth. Based on the information presented in this review, we also identify major research opportunities and gaps in the existing knowledge of abalone metabolism, which when elucidated may not only serve the purpose of better understanding these organisms growth but also could potentially lead to increased productivity of the abalone commercial farming sector. [ABSTRACT FROM AUTHOR]

Introduction: Oxygen is essential for metabolic processes and in the absence thereof alternative metabolic pathways are required for energy production, as seen in marine invertebrates like abalone. Even though hypoxia has been responsible for significant losses to the aquaculture industry, the overall metabolic adaptations of abalone in response to environmental hypoxia are as yet, not fully elucidated.Objective: To use a multiplatform metabolomics approach to characterize the metabolic changes associated with energy production in abalone (Haliotis midae) when exposed to environmental hypoxia.Methods: Metabolomics analysis of abalone adductor and foot muscle, left and right gill, hemolymph, and epipodial tissue samples were conducted using a multiplatform approach, which included untargeted NMR spectroscopy, untargeted and targeted LC-MS spectrometry, and untargeted and semi-targeted GC-MS spectrometric analyses.Results: Increased levels of anaerobic end-products specific to marine animals were found which include alanopine, strombine, tauropine and octopine. These were accompanied by elevated lactate, succinate and arginine, of which the latter is a product of phosphoarginine breakdown in abalone. Primarily amino acid metabolism was affected, with carbohydrate and lipid metabolism assisting with anaerobic energy production to a lesser extent. Different tissues showed varied metabolic responses to hypoxia, with the largest metabolic changes in the adductor muscle.Conclusions: From this investigation, it becomes evident that abalone have well-developed (yet understudied) metabolic mechanisms for surviving hypoxic periods. Furthermore, metabolomics serves as a powerful tool for investigating the altered metabolic processes in abalone. [ABSTRACT FROM AUTHOR]