Seasonal effect on lactate dehydrogenase and citrate synthase in snapper (Pagrus auratus)

Abstract

The activities of two enzymes involved in metabolic energy production, lactate dehydrogenase (LDH) and citrate synthase (CS), were determined in the white trunk musculature of snapper, Pagrus auratus (Bloch & Schneider 1801), to determine whether the metabolic capacity reflects seasonal variations. LDH and CS activities for a population of wild fish were monitored on a monthly basis over a period of 1 year and correlated with body length and seasonal variation. Significant correlations were observed between enzyme activity and body length. Increased LDH activity may reflect energy demand for anaerobic burst swimming. In contrast, declining CS activity with increasing body length may indicate a reduction in energy generation. The seasonal variation of CS activity coincided with the somatic growth cycle, increasing from 1.18 U g -1 white muscle in winter to 1.79 in spring and 1.78 in late summer, whereas LDH activity did not show a clear seasonal pattern. This information could be useful for tracking metabolic capacity in field specimens using simple biochemical analysis. M01019

White epaxial muscle aerobic and anaerobic potential and muscle fiber structure in surface and cave morphotypes of the Mexican cavefish (Astyanax mexicanus)

“…Increases in aerobic capacity in poikilothermic vertebrates have been noted after 2–3 months of thermal acclimation and at increasingly lower temperatures than those we exposed the subtropical Mexican cavefish to (Johnston & Lucking, 1978), which are likely significant contributing factors towards why we did not see an effect of lower temperature acclimation in CS activity. LDH has often not shown a pattern relating to thermal seasonal variation, however (Majed et al, 2002), similar to our findings here.…”

“…Notably, although the cave and surface morphs of Astyanax mexicanus utilized in this study evolved in distinct environmental habitats, they were bred and reared in a controlled laboratory environment, and hence the differences reported herein reflect evolutionary strategies and not short‐term responses to the local environment. Others have found that increased LDH activity may suggest energy demand changes to support anaerobic burst swimming (Majed et al, 2002), suggesting that the increases in lactate we see in cave morphotypes may be functionally associated with burst swimming. Notably, however, cave morphs of Astyanax mexicanus have substantially lower burst speed and their swimming pattern relies predominantly on slow gliding movements rather than more sustained active swimming exhibited in the surface morph, though they are capable of elevating muscle activity under stimulation (Olson et al, 2023).…”

Oxygen consumption and enzyme activity of the subtidal flat oyster(Ostrea chilensis)and intertidal Pacific oyster(Crassostrea gigas):Responses to temperature and starvation

“…Citrate synthase (CS) activity was assayed according to Majed et al (2002). The extraction buffer for CS was adjusted to a final pH of 8.0 at 20°C.…”