1H-NMR-based metabolite profiling of abalone digestive gland in response to short-term starvation

The effect of a short-term feeding and starvation experiment on juvenile abalone (Haliotis rubra x H. laevigata) was investigated. Artificial feed was supplied ad libitum to the fed group and no feed was supplied to the... [ view full abstract ]

The effect of a short-term feeding and starvation experiment on juvenile abalone (Haliotis rubra x H. laevigata) was investigated. Artificial feed was supplied ad libitum to the fed group and no feed was supplied to the starved group. A modified metabolite extraction protocol using deuterated solvents was developed for 1H-NMR based metabolite profiling of digestive gland in response to the short-term feeding/starvation experiment, to avoid lyophilization prior to biochemical analysis. PLS-DA revealed fed and starved abalone are metabolically distinct from each other after 28 and 56 days. After 28 days, the fed group was defined by an increase in arginine, glucose, glutamate, glycine, inosine and uracil (P<0.05) and the starved group defined by an increase in N,N-dimethylglycine. After 56 days, the fed group still displayed increased glucose (P<0.05), while N,N-dimethylglycine remained elevated in the starved group (P<0.05). Arginine and glycogen were all higher at 28 days compared to 56 days, suggesting decreased anaerobic energy production at the later time point. Only glucose and N,N-dimethylglycine were significantly different between the fed and starved groups after 56 days, suggesting that abalone had not acclimatized to the starvation treatment after 28 days. These results infer N,N-dimethylglycine is a robust marker for short-term starvation in abalone. 1H-NMR was also conducted on the artificial feed and starved abalone fecal matter, revealing the biochemical differences between them and digestive gland tissue. These methodology and results will facilitate a deeper understanding of the nutritional and physiological requirements of abalone in an aquaculture setting.