Cardiorespiratory responses to haemolytic anaemia in rainbow trout Oncorhynchus mykiss

Abstract

To quantify cardiorespiratory response to experimental anaemia in rainbow trout Oncorhynchus mykiss, a 24 h phenylhydrazine treatment was used to reduce haematocrit to almost one third of its initial value over 4-5 days. In response, relative blood velocity in the ventral aorta (an index of cardiac output) progressively increased to more than double to its normocythaemic value and there was no significant change in routine oxygen uptake. Thus, the primary compensatory response to anaemia was an increase in cardiac output.

Gill structural change in response to turbidity has no effect on the oxygen uptake of a juvenile sparid fish

“…In more severely affected fish, the increase in haematocrit and haemoglobin concentration was also associated with an increase in heart rate and stroke volume ( Dussault et al ., 2001 ). In another study of interest, Gold et al . (2015) showed that an increase in cardiac output was sufficient to maintain routine oxygen consumption in anaemic rainbow trout that had reduced aerobic capacity ( Gold et al ., 2015 ).…”

“…In another study of interest, Gold et al . (2015) showed that an increase in cardiac output was sufficient to maintain routine oxygen consumption in anaemic rainbow trout that had reduced aerobic capacity ( Gold et al ., 2015 ). Only one study to date has specifically examined the aerobic physiology of fish in response to turbidity ( Lowe et al ., 2015 ) and, in that study, it appeared that the gill ventilation rate of P. auratus was increased in turbid waters, but how this contributed to oxygen uptake across structurally modified gills was unfortunately not ascertained.…”