Physiological Effects of Sublethal Acid Exposure in Juvenile Rainbow Trout on a Limited or Unlimited Ration during a Simulated Global Warming Scenario

Protein synthesis (Ks), net accretion (Kg), and degradation (Kd) in liver, gills, and white muscle were measured using a flooding dose of [3H]phenylalanine in juvenile rainbow trout chronically exposed (90 days) to softwater in the presence or absence of sublethal acidity (H2SO4, pH 5.2) alone or in combination with a 2°C elevation in the normal temperature profile over the months of June-September 1993 (control temperature range 13-24°C). Chronic sublethal exposure to low pH reduced protein synthesis and degradation in both the gill and liver with little apparent impact on white muscle. As a result, protein was increased in the affected tissues. This suggested that both liver and gill have some capacity to compensate for the effects of acid exposure. The 2°C elevation in the normal temperature profile resulted in a slight increase in protein turnover in both gills and liver. However, during the period of peak water temperature, the 2°C elevation in temperature triggered a dramatic reduction in the protein turnover rates in these tissues. The exact mechanism by which these modifications in protein turnover occurred could not be clearly established. Overall, environmental acidification in combination with a summer global warming scenario would decrease fish growth and survival, most notably during periods of peak temperatures.

Download Full-text

Effects of chronic sublethal ammonia and a simulated summer global warming scenario: protein synthesis in juvenile rainbow trout (Oncorhynchus mykiss)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-021 ◽

1998 ◽

Vol 55 (6) ◽

pp. 1534-1544 ◽

Cited By ~ 13

Author(s):

Scott D Reid ◽

T K Linton ◽

J J Dockray ◽

D G McDonald ◽

C M Wood

Keyword(s):

Protein Synthesis ◽

Global Warming ◽

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Protein Turnover ◽

Warming Scenario ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Global Warming Scenario ◽

Protein Synthesis And Degradation ◽

Synthesis And Degradation

Protein synthesis, net accretion, and degradation in liver, gill, and white muscle and ribosomal translational efficiency and protein synthesis capacity in liver and gill were measured using a flooding dose of [3H]phenylalanine in juvenile rainbow trout (Oncorhynchus mykiss). The fish were chronically exposed (90 days) in hardwater to the presence or absence of sublethal ammonia (70 µmol total ammonia ·L-1) alone or in combination with a 2°C elevation in the normal temperature profile over the months of June-September 1993 (ambient temperature range 13-22°C). Chronic sublethal exposure to ammonia had little impact on gill protein synthesis and degradation (protein turnover) and even less in muscle. However, in the liver, both protein synthesis and degradation were stimulated following 60 days of the sublethal ammonia exposure. The 2°C elevation in temperature resulted in a slight increase in protein turnover in both gills and liver. However, during the period of peak water temperature, the 2°C elevation in temperature inhibited protein dynamics in these tissues. Overall, elevated environmental ammonia in combination with a summer global warming scenario would challenge the ability of fish to adapt to alterations in the quality of their environment, most notably during periods of peak temperatures.

Download Full-text