Effect of dietary lipid on response to exercise: relationship to metabolic adaptation

Abstract

The aim of the present study was to relate changes in muscle oxidative capacity and free fatty acid flux in response to oil supplementation to fuel utilisation during subsequent exercise of varying intensities. Following 10 weeks of oil supplementation there was an increased capacity for fat utilisation during low and moderate intensity exercise as indicated by a lower respiratory exchange ratio (RER) (P<0.05). We suggest that this was contributed to by a parallel increase in the oxidative capacity of muscle as indicated by a significant increase in the activity of muscle citrate synthase (CS) (P<0.05) and trend towards an increase in beta-Hydroxy acyl CoA dehydrogenase (beta-HAD), (P>0.05). In addition, low and moderate intensity exercise was associated with an exercise-induced increase in plasma free fatty acids (FFA) and there was an increased facility for uptake of FFA by working muscle from circulating triglycerides, as suggested by an increase in TL activity (P<0.01). The response to oil supplementation varied between individual horses and the magnitude of response, during the low intensity exercise test, in terms of difference in RER was correlated to the increase in CS activity (r2 = 0.95, P<0.05) following oil supplementation. There was no similar significant correlation with respect to FFA, TL or beta-HAD activity (P>0.05). The hypothesis in this study was that the metabolic adaptation to oil supplementation, in terms of exercise response, was related to individual increases in the activities of CS, beta-HAD or TL. However, the relationship between these parameters was unequivocal and requires further investigation, ideally with a larger group of horses.

A survey on the feeding of eventing horses during competition

“…A glucose‐sparing or lactate‐lowering effect was not detected with oil feeding. It is possible that the amounts of oil administered were too low to provide the beneficial effects described in the literature (Greiwe et al., 1989; Frape, 1998; Dunnett et al., 2002; Mattos et al., 2006). Alternatively, it may be that the oil was fed at the wrong time in relation to the commencement of exercise, that is, the majority of the horses received oil in the evening.…”

State of the art on daily rhythms of physiology and behaviour in horses

“…In the same hours it was also was possible to observe linoleic and linolenic acids acrophases that did not differ from the acrophase observed in the sedentary horse. In the athletic horse, the effect of physical exercise on the haematic concentration of NEFA is well documented (Dunnett et al 2002). NEFA are highly energetic metabolites whose metabolic contributions are inversely proportional to the work intensity and directly proportional to duration (Hambitzer and Bent 1988;Caola and Assenza 2001).…”

Adaptação metabólica de equinos suplementados com óleos vegetais em testes de longa duração

“…Dunnett et al (2002) encontraram resposta metabólica após três semanas de suplementação com óleo vegetal, porém, dentro de cinco semanas após o término da suplementação, as concentrações séricas dos componentes lipídicos voltaram ao valor basal. Portanto, a suplementação com óleo tem efeitos transitórios e depende do seu uso contínuo.…”