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Hormonal patterns in normal and hyperleptinemic mares in response to three common feeding-housing regimens.
J Anim Sci. 2007 Nov; 85(11):2873-81.JA

Abstract

We previously reported that a rise in plasma leptin concentrations followed the rise in insulin and glucose in meal-fed horses, whereas horses maintained on pasture had little fluctuations in hormonal patterns. We have also described a hyperleptinemic-hyperinsulinemic condition that occurs in about 30% of our light horse mares of high body condition maintained on pasture. The present experiment was designed to 1) study the effect of 3 common feeding-housing regimens on leptin and other metabolic hormones in mares and 2) determine whether the hyperleptinemic condition interacted with these regimens. Six light horse mares with high body condition (average score = 7) were assigned to 2 simultaneous 3 x 3 Latin squares, 1 with normal mares (leptin = 0.1 to 6 ng/mL) and 1 with mares displaying hyperleptinemia (>10 ng/mL). Three feeding-housing regimens were compared: ad libitum pasture, ad libitum native grass hay in an outdoor paddock, and single morning feedings of a pelleted concentrate and hay at 0700 in a barn. Five days of acclimation to the feeding regimens were followed by a 36-h period of hourly blood collection to characterize the hormonal characteristics. Leptin concentrations were elevated (P < 0.001) in mares predetermined to be hyperleptinemic compared with normal mares, regardless of the feeding regimen. Leptin was greatest (P < 0.01) in mares on pasture and least in mares fed hay. Variations over time (P < 0.01) were present for all hormones and metabolites studied. Glucose and insulin concentrations were greatest (P < 0.01) in mares on pasture, with meal-fed mares exhibiting an immediate rise in plasma concentrations of both after feeding. Mares on hay had low and constant concentrations of glucose, insulin, and leptin, with no apparent fluctuations. Cortisol, prolactin, and IGF-I did not differ with leptin status, whereas GH differed due to feeding-housing regimen (P < 0.02); there was also an interaction of leptin status and feeding-housing regimen for GH concentrations (P = 0.094). It was concluded that 1) estimates of hormonal secretion in horses based on frequent sampling, depending upon the hormone in question, can be profoundly affected by the feeding-housing regimens, and 2) the hyperleptinemic condition persists under differing conditions of feeding-housing.

Authors+Show Affiliations

School of Animal Sciences, Louisiana Agriculture Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17591706

Citation

Storer, W A., et al. "Hormonal Patterns in Normal and Hyperleptinemic Mares in Response to Three Common Feeding-housing Regimens." Journal of Animal Science, vol. 85, no. 11, 2007, pp. 2873-81.
Storer WA, Thompson DL, Waller CA, et al. Hormonal patterns in normal and hyperleptinemic mares in response to three common feeding-housing regimens. J Anim Sci. 2007;85(11):2873-81.
Storer, W. A., Thompson, D. L., Waller, C. A., & Cartmill, J. A. (2007). Hormonal patterns in normal and hyperleptinemic mares in response to three common feeding-housing regimens. Journal of Animal Science, 85(11), 2873-81.
Storer WA, et al. Hormonal Patterns in Normal and Hyperleptinemic Mares in Response to Three Common Feeding-housing Regimens. J Anim Sci. 2007;85(11):2873-81. PubMed PMID: 17591706.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hormonal patterns in normal and hyperleptinemic mares in response to three common feeding-housing regimens. AU - Storer,W A, AU - Thompson,D L,Jr AU - Waller,C A, AU - Cartmill,J A, Y1 - 2007/06/25/ PY - 2007/6/27/pubmed PY - 2007/12/28/medline PY - 2007/6/27/entrez SP - 2873 EP - 81 JF - Journal of animal science JO - J Anim Sci VL - 85 IS - 11 N2 - We previously reported that a rise in plasma leptin concentrations followed the rise in insulin and glucose in meal-fed horses, whereas horses maintained on pasture had little fluctuations in hormonal patterns. We have also described a hyperleptinemic-hyperinsulinemic condition that occurs in about 30% of our light horse mares of high body condition maintained on pasture. The present experiment was designed to 1) study the effect of 3 common feeding-housing regimens on leptin and other metabolic hormones in mares and 2) determine whether the hyperleptinemic condition interacted with these regimens. Six light horse mares with high body condition (average score = 7) were assigned to 2 simultaneous 3 x 3 Latin squares, 1 with normal mares (leptin = 0.1 to 6 ng/mL) and 1 with mares displaying hyperleptinemia (>10 ng/mL). Three feeding-housing regimens were compared: ad libitum pasture, ad libitum native grass hay in an outdoor paddock, and single morning feedings of a pelleted concentrate and hay at 0700 in a barn. Five days of acclimation to the feeding regimens were followed by a 36-h period of hourly blood collection to characterize the hormonal characteristics. Leptin concentrations were elevated (P < 0.001) in mares predetermined to be hyperleptinemic compared with normal mares, regardless of the feeding regimen. Leptin was greatest (P < 0.01) in mares on pasture and least in mares fed hay. Variations over time (P < 0.01) were present for all hormones and metabolites studied. Glucose and insulin concentrations were greatest (P < 0.01) in mares on pasture, with meal-fed mares exhibiting an immediate rise in plasma concentrations of both after feeding. Mares on hay had low and constant concentrations of glucose, insulin, and leptin, with no apparent fluctuations. Cortisol, prolactin, and IGF-I did not differ with leptin status, whereas GH differed due to feeding-housing regimen (P < 0.02); there was also an interaction of leptin status and feeding-housing regimen for GH concentrations (P = 0.094). It was concluded that 1) estimates of hormonal secretion in horses based on frequent sampling, depending upon the hormone in question, can be profoundly affected by the feeding-housing regimens, and 2) the hyperleptinemic condition persists under differing conditions of feeding-housing. SN - 1525-3163 UR - https://www.unboundmedicine.com/medline/citation/17591706/Hormonal_patterns_in_normal_and_hyperleptinemic_mares_in_response_to_three_common_feeding_housing_regimens_ L2 - https://academic.oup.com/jas/article-lookup/doi/10.2527/jas.2007-0182 DB - PRIME DP - Unbound Medicine ER -