Exploring basic biochemical constituents in the body tissues of South African abaloneHaliotis midaereared in shore-based mariculture systems

Abstract

The study quantifies the effects of season, age and feeding regime on glucose, glycogen, proteins and lipids in abalone Haliotis midae tissues, and to assess water loss during simulated live export. Abalone of two age classes, younger (~30 months old) and older (~38 months old), were subjected to four dietary regimes: two single feeds, kelp and an artificial feed, and two rotational feeding regimes utilising kelp and the artificial feed in varying ratios. Total protein, free glucose, glycogen and total lipid content were determined in the digestive gland and foot/adductor muscle. One subset of older animals, from each feeding treatment, was subjected to water content analysis by drying. Subsets of older and younger animals were subjected to a simulated live export trial to determine mass loss. Digestive gland tissue proved to be of little value for routine monitoring. Muscle glucose, muscle lipid and muscle protein concentrations were affected by month and age. Muscle glycogen concentration was affected by month, age and feeding regime. During simulated export trials, animals lost on average 15% body mass, being significantly higher (p < 0.01) in younger compared to older animals. Feeding regime did not influence susceptibility to mass loss during export. Animal age influenced the biochemical composition and export performance of abalone.

Effect of proline-enriched abalone feed on selected metabolite levels of slow-growing adultHaliotis midae

“…Research done on plants show that during stress, proline and lipid metabolism share dual roles (Shinde, Villamor, Lin, Sharma, & Verslues, ), suggesting that proline has the ability to regulate β‐oxidation, subsequently resulting in decreased acetylcarnitine and an increase in alanine, as seen in this experiment (Figure ). Furthermore, adult abalone have the capacity to accumulate lipid stores, suggesting an increased dependence on a pathway like β‐oxidation for energy production in H. midae (Laas & Vosloo, ). Based on a dietary lipid investigation conducted on H. iris, it was concluded that lipids do not significantly affect the growth of this abalone species (Tung & Alfaro, ), which could be true for H. midae as well.…”

Abalone growth and associated aspects: now from a metabolic perspective

“…). Poor perfusion, high glycogen reserves (Laas & Vosloo ) and the diversity in anaerobic enzymes (Gäde ; O'omolo et al . ) suggest that the foot muscle relies primarily on anaerobic glycolysis for energy generation.…”

“…). Due to these dynamic functions, biochemical constituents of the digestive gland tissue are highly variable (Laas & Vosloo ), and there have been conflicting reports of digestive gland glycogen decreasing (Carefoot et al . ) or remaining unchanged (Sheedy et al .…”

“…Despite this however, knowledge of abalone metabolism and the biochemical processes associated with growth, development and feeding are not. This fact becomes evident when reviewing the existing scientific literature and is further substantiated by Morash and Alter (): ‘We are at a crucial time where understanding the mechanistic physiology of abalone will give us an advantage as the climate continues to change and farming practices become more industrialised.’ , Laas and Vosloo (): ‘Knowledge of the basic biochemical constituents of abalone under culture conditions would be a very useful tool in their management in aquaculture systems.’ , and Sales and Janssens (): ‘Evaluation of the effective use of feed ingredients in abalone feeds is not only hampered by a lack of knowledge on nutrient requirements and possible anti‐nutritional factors present in some feed ingredients, but also by an effective measurement of the response to these.’ As the future of sustainable abalone aquaculture depends on optimal growth rates, the various growth mechanisms involved has become a popular research topic.…”

“…Abalone farming on the other hand serve to supply to the growing demand, without depleting the natural abalone reserves, and have shown exponential growth since the mid-1990s. South African abalone are now successfully cultured in man-made, shore-based systems, where they are increasingly grown on formulated artificial feeds (Laas & Vosloo 2010). Due to its unique gustatory properties, special nutritional value and the safety standards that this food has to comply with, for commerce, these abalone are in high demand and of high monetary value (Øiseth et al 2013;Latuihamallo & Apituley 2015).…”