Distortions in Sensitivity of Carotid Baroreceptor Reflexes in Rabbits Following Consumption of Two Forms of Palm Oil Diets

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Aim: Long term consumption of dietary oils has been implicated in the etiology of hypertension. This study seeks to compare the effects of long term consumption of fresh palm oil (FPO) and thermoxidized palm oil (TPO) on baroreceptor reflex sensitivity (BRS), which is responsible for short term regulation of blood pressure. Methodology: The design of this study involved the use of eighteen, male, five month old New Zealand rabbits weighing 750 – 1000 g. They were divided into three groups (n = 6) as follows; control group (received normal animal feed only), FPO diet – fed group (received animal feed mixed with fresh palm oil in the ratio 85:15, respectively) and TPO diet – fed group (received animal feed mixed with thermoxidised palm oil in the ratio 85:15, respectively). The animals were fed for 6 months, after which they were used for the various experiments. Results: Mean daily food and water intake in FPO and TPO fed groups was significantly (p<0.001) lower compared with control. Heart rate for FPO group was significantly higher than the control Original Research Article Ani et al.; BJMMR, 8(3): 245-255, 2015; Article no.BJMMR.2015.445 246 (p<0.001) and TPO (p<0.01) group. Basal systolic and diastolic blood pressures were significantly higher in TPO group than in the FPO and control (p<0.05) group. The FPO group also had a significantly lower basal systolic (p<0.01) and diastolic pressure (p<0.001) than the control group. The basal pulse pressure was significantly lower in the FPO group than the control (p<0.001) and the TPO group (p<0.01). The mean arterial pressure (MAP) for TPO group was significantly higher (p<0.001) than that of control and FPO groups. The baroreflex sensitivity for FPO group was significantly reduced compared with control (p<0.01) and TPO group (p<0.05). The TPO group showed a significantly lower (p<0.01) baroreflex sensitivity, compared with control. Conclusion: This study observed that chronic consumption of both fresh and thermoxidised palm oil diets caused a significant reduction in carotid baroreceptor reflex sensitivity. However, reduction in BRS was more in fresh palm oil – diet fed group, than the thermally oxidized palm oil diet – fed.