Effects of chromium supplementation on selected metabolic responses in resting and exercising horses

Abstract

Link to this article: http://journals.cambridge.org/abstract_S1478061506000041How to cite this article: I Vervuert, D Cuddeford and M Coenen (2006). Effects of chromium supplementation on selected metabolic responses in resting and exercising horses. AbstractChromium (Cr) is required for insulin function in the control of cellular glucose uptake. Other functions of Cr relate to its effects on growth, lipid metabolism, immune responses and interactions with nucleic acids. This study was conducted to obtain information on the effect of Cr supplementation on the metabolic responses of five exercising Standardbred horses. During the experiment, horses were fed every day for a 21-day period in a randomized order either a yeast product without Cr (control) or with 4.15 or 8.3 mg Cr day 21 . Horses were exercised on a treadmill, alternating a work day of low-speed exercise at 5 m s 21 on a 3% incline for 45 min with a rest day. Each horse was adapted over a 21-day period to his or her respective supplementation before undergoing a standardized exercise test (SET). The SET comprised five incremental steps, each of 4 min duration, on a treadmill with a 3% incline; the first step was at 5 m s 21 and was followed with increments of 1 m s 21 . Blood samples were taken for lactate, plasma glucose, serum insulin and cortisol estimation before, during and after each SET (30, 120 min and 24 h post-exercise). Blood Cr was estimated 2 h after feeding the control or Cr-enriched yeast (intake 8.3 mg Cr) in two horses. Heart rate was monitored throughout each SET. Blood lactate and plasma glucose peaks were highest at 8 and 9 m s 21 during the SET when 8.3 mg Cr was supplied. Serum insulin levels declined during the SET and there were no treatment-related changes. Twenty-four hours after exercise, plasma glucose and serum cortisol concentrations returned to basal levels or lower. Serum insulin rebounded 30 min after exercise but 24 h later, serum insulin concentrations were below resting levels. During the recovery period, Cr supplementation did not clearly affect metabolic responses. These results suggest that Cr supplementation had no beneficial effect in healthy, exercising horses.

Chromium or l-carnitine supplementation during an aerobic conditioning program mildly modified the energy metabolism biomarker response in Mangalarga Marchador fillies

“…Daily supplementation with 10 mg Cr for 29 days decreased HR right after 50 min of marcha tests (3.3 m s À 1 ) besides leading to a lower HR value during recovery after exercise (Jordão et al, 2010). On the other hand, there are reports in the literature of no effect of Cr supplementation on HR during exercise (Gentry et al, 1999;Pagan et al, 1995), even though others report that HR increased in the supplemented group (Vervuert et al, 2006). As for LC supplementation, in accordance to the present study, no effect was shown on HR during standardized treadmill exercise (Niemeyer et al, 2005) and during field tests with animals under training for eventing (Iben et al, 1999).…”

“…Hence, Cr supplementation for at least seven days may have been enough to potentialize the effects of insulin and increase the availability of intracellular glucose as a substrate for glycolysis with the consequent increase in lactate production. Although the marcha test intensity was low and favored lipid oxidation, Cr supplementation may have favored glycolysis as in other reports that Cr supplementation resulted in higher lactate levels both during exercise (Vervuert et al, 2006) and after exercise (Gentry et al, 1999). Nevertheless, Pagan et al (1995) reported a decrease in blood lactate (P ¼0.08) in the early phases of the progressive treadmill exercise for animals supplemented with Cr, while Jordão et al (2010) reported no effect of such supplementation on blood lactate either during or after exercise.…”

“…Unlike the present study, Pagan et al (1995) reported lower blood glucose levels during incremental treadmill exercise tests of horses supplemented with Cr. However, there are also reports of no change during rest (Gentry et al, 1999;Vervuert et al, 2006) and of increased blood glucose levels right after exercise (Vervuert et al, 2006), while Jordão et al (2010) did not report an effect of Cr supplementation on blood glucose levels measured immediately after 50-min marcha field tests with MM mares. Stressful situations, diseases, and intense exercise (Anderson et al, 1988) increase the urinary excretion of Cr and, according to Pagan et al (1995), whether the animal is Cr-deficient or not is a key factor for any response to supplementation.…”

Effects of chromium yeast supplementation on postprandial glycaemic and insulinaemic responses in insulin-resistant ponies and horses

“…Unlike these results, Vervuert et al (2006) found higher plasma glucose levels during exercise in Cr-supplemented healthy horses. Cartmill et al (2005) found that dietary Cr supplementation had no effect on glucose dynamics or insulin sensitivity in mature horses with high body condition scores and hyperleptinaemia.…”

Effects of a supplement containing chromium and magnesium on morphometric measurements, resting glucose, insulin concentrations and insulin sensitivity in laminitic obese horses

“…Chromium supplementation has previously been evaluated in horses, but results have varied markedly among studies (Ott and Kivipelto 1999; Vervuert et al . 2006; Uyanik et al .…”