The objective of this study was to more clearly define the relationship between
body condition, plasma leptin and insulin-like growth factor-I (IGF-I) in stallions and
geldings in moderate (5.0-5.5) versus fleshy (7.0-7.5) body condition. Data analyses of
physical measurements showed that there was a difference for BCS (P<0.001) even
though the fat group only achieved a mean BCS of 6.3 + 0.2 as compared with a mean
BCS of 5.3 + 0.1 for the moderate group. Differences also existed for rump fat (P<0.05)
and percent body fat (P<0.05) between BCS groups. Analysis of physical measurements
revealed that there was no sex effect as geldings and stallions within each group were not
significantly different. Analysis of plasma leptin concurred with previous reports as a
difference (P<0.001) existed between the BCS groups. Mean leptin concentrations were
2.13 + 0.1 ng/ml for the fat group and 1.44 + 0.1 ng/ml for the moderate group. After
normalization of the data, changes in leptin concentrations still revealed a significant
difference (P<0.05) between BCS groups, yet no difference in leptin concentrations
between stallions and geldings was seen. Dexamethasone (DEX) treatment on d 0 caused
a subsequent 24 h rise in plasma leptin in both groups. Analysis of plasma IGF-I
revealed no difference in IGF-I concentrations between BCS groups. Mean plasma IGF-I
was 347.2 + 11.4 ng/ml for the fat group and 344.3 + 10.0 ng/ml for the moderate group. There was however a difference (P<0.05) between geldings and stallions. Geldings
exhibited an overall mean plasma IGF-I concentration of 360.6 + 9.1 ng/ml with stallions
exhibiting a mean IGF-I concentration of 329.1 + 12.1 ng/ml. The post DEX challenge
rise seen with leptin was not evident when analyzing the change in plasma IGF-I
concentrations. In conclusion, the data presented herein have provided a more accurate
profile of circulating concentrations of leptin and IGF-I in stallions and geldings of
moderate and fleshy body condition.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1035 |
| Date | 15 May 2009 |
| Creators | Chancellor, Tommy Neal |
| Contributors | Vogelsang, Martha M. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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