Effect of Diet on the Cardiovascular System in Healthy Beagles

Abstract

ABSTRACT. In management of canine cardiac disorders, cardiac drugs are commonly administered with food, although the cardiovascular effects of feeding and frequency of feeding are unknown. This study investigated the cardiovascular effect of feeding and frequency of feeding using a telemetry monitoring system in unanesthetized and unrestrained dogs. Systolic and diastolic blood pressure, heart rate and double product were steeply elevated during the five minutes immediately before feeding. They showed a sharp fall within 60 min after feeding time, especially the systolic and diastolic blood pressure, which showed lower values than from before feeding time. There were no significant differences in the means of preprandial elevation, postprandial fall or 24-hr averages in the once-and twice-daily feeding periods.KEY WORDS: blood pressure, canine, cardiovascular effect, feeding, telemetry system. J. Vet. Med. Sci. 72(5): 615-619, 2010 Cardiovascular disorders are common in elderly dogs, one-third of which have been shown to suffer from valvular heart disease [2]. Vasodilators such as angiotensin-converting enzyme inhibitors, beta-blockers and diuretics are commonly prescribed in this situation [2], and these drugs are usually administered with food for the sake of convenience. Some studies [5,12,13] that have used telemetry systems to track systolic blood pressure (SBP) and diastolic blood pressure (DBP) in dogs have suggested that feeding regimens affect canine variations of blood pressure (BP) and heart rate (HR). Household dogs are generally fed once or twice a day, depending on the lifestyle of the owner, and the precise cardiovascular effects of various times of feeding are not known. The purpose of this study was to examine the influence of feeding and times of feeding on the variation of BP, HR and double product (DP), a parameter of oxygen consumption, in healthy Beagles.Animals: Three healthy female Beagles (mean age of 7.3  4.6 years; mean weight of 9.1  0.3 kg) were used in this study. Based on the results of a physical examination, complete blood count and serum chemistry, the dogs were confirmed to be healthy. They were acclimated for 10 weeks under experimental conditions at the Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Nippon Veterinary and Life Science University.Feeding time: Food (Hill's Science Diet Canine Maintenance) was given at 15:00 in the once-daily feeding group and at 9:00 and 17:00 in the twice-daily feeding group. Water was given ad libitum.Experimental environment: The dogs were housed in individual stainless steel cages measuring 710 (W)  1,095 (D)  795 (H) mm. The cages were placed under environment conditions similar to those for household animals; human entry to the room was unlimited from 7:00-24:00, and neither the room temperature nor the lighting cycle was controlled.Procedures: This experiment was carried out in a crossover design. Placement of a BP telemetry system (Data Science International, New Brighton, MN, U.S.A.) and collection o...

Influence of feeding schedules on the chronobiology of renin activity, urinary electrolytes and blood pressure in dogs

“…In all feeding groups SBP and DBP exhibited a marked fall just after food intake. The observed drop in BP, which is consistent with previous studies in healthy beagle dogs (Gelzer & Ball, 1997;Mishina et al, 1999;Miyazaki et al, 2002;Nakagawa et al, 2010), is likely related to the decreased activity of renin, and the secretion of vasodilatory gut peptides, such as neurotensin and insulin (Shibao et al, 2007). Indeed, intravenous infusions of insulin at physiological levels have been shown to reduce BP in patients with autonomic disorders (Brown et al, 1989).…”