Characterising in vivo cardiac function in the rat following supplementation of human dietary achievable fish oil doses

Background: Regular fish consumption is consistently associated with a range of health benefits, particularly cardiovascular related. In excitable tissue such as skeletal and cardiac muscle, fish or fish oil (FO) intake increases membrane phospholipid concentration of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA), especially docosahexaenoic acid (DHA). Of physiological consequence, skeletal muscle and cardiac function has been demonstrated to be modified, even during episodes of hypoxia/ischaemia. There is evidence that shows variation in the patterns by which DHA phospholipid incorporation occurs according to tissue type. However, little is known about whether incorporation of DHA is associated with specific physiological properties unique to the tissue. In addition, it is not known if physiological effects can be attributed to the supplementation of FO doses achievable within a typical Westernstyle human diet (high SFA and n-6 PUFA). Some physiological effects have been reported in skeletal muscle using human dietary achievable FO doses. The physiological effects demonstrated within the myocardium and pacemaker regions of the heart are postulated to underpin the cardiovascular health benefits of regular fish intake observed at a population level. However, previous studies have relied upon FO doses well above what could be achieved in the habitual human diet. This research therefore aimed, firstly, to characterise patterns of phospholipid DHA incorporation throughout muscle types with unique physiological properties, including ventricular myocardium, following supplementation of FO doses achievable within a typical Western-style human diet. Secondly, it aimed to relate ventricular myocardial phospholipid DHA concentrations to cardiac physiology at rest; and during ischaemia and reperfusion; that may explain the cardiovascular health benefits associated with regular fish consumption in humans.