Download Cardiac Performance of an Athletic Teleost

Cardiac performance of an athletic teleost:
The yellowtailed kingfish, Seriola lalandi
Bachelor of Philosophy in Physiology and Anatomy
1990
Kara Lee Hutchison
Abstract
Cardiac performance is considered to be an important determinant of swimming
performance in fish. The present study examines how form and function of the heart
enable athletic fishes to meet the level of cardiac performance required by their lifestyle.
An in situ saline perfused heart preparation was used to investigate the cardiac
performance of the kingfish (Seriola lalandi), a fast swimming predatory species. The
results are compared in this study to data from the literature on cardiac performance of
the eel, trout and tuna. The eel (Anguilla dieffenbachii) and the rainbow trout
(Oncorhynchus mykiss) are both considered to have less active lifestyles than the kingfish
and the yellowfin tuna (Thunnus albacares) is a very athletic fish.
The kingfish heart xhibited the Frank-Starling response of increased cardiac output as
input pressure was increased, and the mechanism of homeometric regulation in response
to increases in output pressure. Maximum cardiac output was 76.5 ml.min-l .kg body
mass-1, more than 70% higher than maximum cardiac output recorded for hearts of eels
and trout. Maximum power output of the heart was 8.7 mW.g ventricle mass-1, the
highest power output recorded for any fish heart preparation, including hearts from tuna.
The hearts of the athletic species show trends towards lower working input pressures and
higher working output pressures. In addition, the most active fishes have larger hearts
with a higher proportion of compact myocardium, higher and more variable heart rates
and smaller and less variable stroke volumes. These strategies are similar to those which
have been adopted by the hearts of mammals to meet their cardiovascular demands.