Effects of a single day of feed restriction on changes in serum leptin, gonadotropins, prolactin, and metabolites in aged and young mares

McManus, Christina J.; Fitzgerald, B. P.

doi:10.1016/s0739-7240(00)00061-8

Cited by 107 publications

(62 citation statements)

References 20 publications

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“…All samples were analysed twice. Plasma leptin concentration was determined using a radioimmunoassay leptin RIA multi-species kit (Millipore/Linco Research, St. Charles, USA), previously validated for use in horses (McManus and Fitzgerald, 2000). Samples were counted for 1 min using a gamma counter (Packard Instruments Company, Ramsey, USA).…”

Section: Horsesmentioning

confidence: 99%

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

Kędzierski

2014

Animal

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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.

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Section: Horsesmentioning

confidence: 99%

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

Kędzierski

2014

Animal

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“…Blood analysis Plasma leptin concentration was determined using a multispecies leptin radioimmunoassay (RIA) kit (Linco Research, St Louis, MO, USA), previously validated for use with horses (McManus and Fitzgerald, 2000), demonstrating an assay coefficient of variation (CV) of 8.5%. The lowest level of leptin that can be detected by this assay is 1 ng/ml.…”

Section: Exercise Test Protocolmentioning

confidence: 99%

“…Short-term feed deprivation leads to a decrease in the mean plasma concentration of leptin in mares (Buff et al, 2005 and2006). The changes in circulating leptin concentration according to the nutritional status indicate that the production of this protein by fat tissue is modulated by several factors (McManus and Fitzgerald, 2000). It has been demonstrated that the synthesis of leptin in humans is stimulated by food intake, insulin and glucocorticoids.…”

Section: Introductionmentioning

confidence: 99%

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

Kędzierski¹,

Kapica²

2008

Animal

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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.

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“…XL-85K, Linco Research Inc., St. Charles, MO, USA). According to McManus and Fitzgerald [18], the results are reported as human equivalents of immunoreactive leptin (ir-leptin), since purified equine leptin was not available.…”

Section: Milk Constituents and Hormone Determinationsmentioning

confidence: 99%

“…Serum leptin has been studied in mares in relation to reproductive activity [18], however no data are available on the leptin content of mares' milk. Since leptin may stimulate the functional development of the neonate and because newborn horses have a rapid growth rate, we decided to investigate leptin in mares' colostrum and milk.…”

Section: Introductionmentioning

confidence: 99%

Major constituents, leptin, and non-protein nitrogen compounds in mares' colostrum and milk

Salimei¹,

Varisco²,

Rosi³

2002

Reprod. Nutr. Dev.

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-Five Haflinger mares were hand-milked at 0 h (pre-suckle) and 6 h (postsuckle), 12, 24, 48, 72 and 96 h after parturition. Total solids, protein, fat, lactose, calculated gross energy content, leptin and non-protein nitrogen components (urea, a-amino nitrogen, creatinine and allantoin) were determined. The levels of the major constituents differed significantly in pre-suckle colostrum from subsequent samples. Leptin levels were the highest in whole (9 ng . mL -1 of immunoreactive human equivalent HE ± 0.48 ng . mL -1 , SEM) and skimmed (7.8 ng HE . mL -1 ± 0.52 ng . mL -1 , SEM) pre-suckle colostrum, declined sharply at 6 hours postpartum, and more slowly subsequently. Mean urea concentration was constant at around 5.0 mM, while a-amino N increased over the observation period and creatinine and allantoin decreased. These findings provide a further indication that mares' milk can be regarded as a functional food. mares' milk / colostrum / major constituents / leptin / non-protein nitrogenRésumé -Principaux constituants, leptine et métabolites d'azote non protéique dans le colostrum et le lait de jument. Cinq juments Haflinger ont été traitées à la main aux temps 0 (avant tétée) et 6 (après tétée), 12, 24, 48, 72 et 96 heures après le poulinage. Les paramètres évalués sur ces échantillons ont été les principaux constituants de la sécrétion mammaire (matière sèche, protéines, lipides, lactose), le contenu énergétique brut et la leptine ; en plus, on a considéré les teneurs en urée, a-aminoacides, créatinine et allantoïne. Une différence significative a été observée entre les valeurs enregistrées dans le colostrum prélevé avant la tétée et dans les autres échantillons. De même, des variations dynamiques concernant la leptine immunoréactive ont été relevées au cours de l'essai : les valeurs étaient les plus fortes dans le lait entier (9 ng . mL -1 équivalent de leptine humaine HE ± 0,48 ng . mL -1 , SEM) et dans le colostrum écrémé (7,8 ng HE . mL -1 ± 0,52 ng . mL -1 , SEM) prélevés avant la tétée. La concentration en urée était en moyenne de 5,0 mM et la concentration en azote des a-aminoacides dénote des bilans différents par rapport à celui mis en évidence pour la créatinine et pour l'allantoïne. Ces résultats contribuent à faire considérer le lait de jument comme un aliment fonctionnel.lait de jument / colostrum / constituants du lait / leptine / non-protein nitrogen Reprod. Nutr. Dev. 42 (2002) 65-72 65

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Effects of a single day of feed restriction on changes in serum leptin, gonadotropins, prolactin, and metabolites in aged and young mares

Cited by 107 publications

References 20 publications

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

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

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

Major constituents, leptin, and non-protein nitrogen compounds in mares' colostrum and milk

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