Endocrine responses in mares and geldings with high body condition scores grouped by high vs. low resting leptin concentrations1

The hypothesis for this study was that a higher dietary proportion of soluble fibre would result in stable and constant plasma metabolite and regulatory hormone concentrations. The study was a 4 × 4 Latin Square design with a sequence of 17 days adaptation to the ration followed by 8 sampling days. The feed rations consisted of only timothy hay (H), hay plus molassed sugar beet pulp combined with either whole oats (OB) or barley (BB) and hay plus a loose chaff-based concentrate (M). Four horses were fitted with permanent caecal cannulas and liquid caecal content was withdrawn manually and blood was drawn from the jugular vein at 0, 3 and 9 h postprandial. The horses were exercised daily at medium level for about 1 h. Samples were analysed for shortchain fatty acids (SCFA) and metabolic traits. Caecal SCFA and propionic acid concentrations increased with increased dietary starch and soluble fibre. The diet highest in soluble fibre (M) resulted in the highest plasma glucose and insulin concentrations in the morning, which then remained stable and constant throughout the day. A strong interaction (P < 0.01) between time and diet was measured for plasma urea, glucose, insulin and leptin. The greatest variations in plasma glycaemic and insulinaemic responses were associated with the cereal grain diets (OB and BB). There were indications of a negative energy balance, which was reflected in a significantly higher plasma β-hydroxybutyrate concentration and a numerically higher non-esterified fatty acid concentration. In conclusion, this study found that inclusion of soluble fibre resulted in increased total caecal SCFA and propionic acid concentrations. This consequently resulted in stable and constant plasma glycaemic and insulinaemic responses. Diets with a high content of soluble fibre provided enough energy for horses at medium work level.

Section: Dietary Compositionsupporting

confidence: 74%

Metabolic response to dietary fibre composition in horses

Brøkner

Austbø

Næsset

et al. 2016

“…This observation is consistent with the previous reports. Cartmill et al (2003) and Piccione et al (2004) did not find any change in the leptin level of exercised horses. Gordon et al (2007b) only noted a decrease in the plasma leptin concentration 24 h after Standardbred mares had been exercised.…”

Section: Discussionmentioning

confidence: 70%

“…Therefore, harnessing horses studied here also had higher plasma leptin concentration determined at rest than other horses. On the contrary, the work by Cartmill et al (2003) showed that horses with similar BCS could have various levels of leptin in the blood. However, higher plasma leptin concentration at rest in horses from group H cannot be the reason of post-exercise increase of about 60% observed in this adipokine during this study.…”

Section: Discussionmentioning

confidence: 98%

Changes in plasma leptin concentration during different types of exercises performed by horses

Kędzierski

2014

Leptin is a tissue-derivative adipokine that regulates appetite, food intake and energy expenditure. It is still not clear how exercise affects plasma leptin concentration in horses. The aim of this study was to evaluate the influence of exercise intensity and duration on plasma leptin levels in working horses. A total of 38 horses were prospectively included in the study and grouped according to the type of exercise they performed: dressage (six stallions, group D), jumping (12 stallions, group J), race (12 Thoroughbred horses, six stallions and six mares, group R) and harness (10 light draft stallions, group H). Blood samples were taken both before and after routine exercise (immediately after the exercise, 30 min and 24 h after). Blood lactic acid (LA) and plasma concentration of leptin, cortisol, uric acid, triacylglycerols, glycerol and free fatty acids were determined. Immediately after exercise, group R had the highest level of LA, whereas groups D and J had the lowest levels. A significant increase in plasma leptin concentration was stated only in group H in samples taken immediately after the end of the exercise period and 30 min after the exercise period, as compared with the values obtained at rest. A significant increase in plasma cortisol concentration was found immediately after the end of the exercise period in groups R and H. Leptin exercise-to-rest ratio was significantly correlated with cortisol exercise-to-rest ratio (r = 0.64; P < 0.001). The increase in plasma leptin concentration in exercised horses was related to the increased plasma cortisol concentration and took place only during long-lasting exercise, which was not intensive.Keywords: cortisol, leptin, horse, exercise ImplicationsLeptin is an adipokine that regulates energetic metabolism, appetite and food intake in mammals. The effect of exercise on plasma leptin concentration in horses is still not clear. The results of the present study indicate that some kinds of exercise increase the plasma leptin level in horses. Better understanding of the regulation of leptin release during exercise could contribute towards improving the performance and state of health of exercising horses; it is thus clear that detailed knowledge of improving the performance of trained horses will have an economic importance. The data presented in this study have never been published elsewhere.

“…The direct effect of exercise on the plasma leptin concentration in horses has not been reported. An increase of leptin value was indicated 180 min after 5 min of lunging only in mares selected for high leptin concentration (Cartmill et al, 2003). In the study of Gordon et al (2007b), short-term high-intensity exercise did not lead to changes in the leptin level during the first 60 min after the test, but the decrease was shown in this hormone plasma concentration 24 h later.…”

Section: Discussionmentioning

confidence: 89%

Plasma concentration of leptin and ghrelin in Standardbred foals as related to the age, sex, exercise and training

Kędzierski¹,

Kapica²

2008

The effect of acute exercise was studied in a group of 42 clinically healthy young Standardbred trotters. These trotters had been divided into four groups according to their age. Their ages were from 1.5 to 3 years. Three jugular venous blood samples were collected via venipuncture from each horse. These samples were collected while (1) at rest, (2) after the end of the exercise and (3) 30 min after the end of the exercise. Exercise showed a significant increase in plasma leptin concentration (3.8 6 0.31 at rest v. 4.3 6 0.37 just after exercise and 4.4 6 0.47 ng/ml after a 30-min rest; ANOVA P , 0.05). The difference between values obtained 30 min after exercise and at rest was significantly greater in 1.5-year-old horses than in those aged 2.5 years (11.3 6 0.43 v. 10.1 6 0.15 ng/ml; ANOVA P , 0.05). The mean plasma leptin concentration was higher in fillies than in colts (4.9 6 0.47 v. 3.5 6 0.36 ng/ml; ANOVA P , 0.05). A positive correlation between the plasma concentrations of leptin and triacylglycerides measured just after exercise was detected (r 5 0.65). The acute exercise significantly increased the plasma concentration of ghrelin that was measured just after exercise (1255 6 55.9 v. 1127 6 54.2 pg/ml; ANOVA P , 0.05). The exercise-induced age-related changes in the plasma ghrelin concentration were significantly lower in 2.5-year-old trotters than in 1.5-year olds. To sum up, the changes in plasma leptin and ghrelin concentrations during bouts of exertion tend to decrease with age and/or training of Standardbred foals.