Publikationsdatenbank

Effects of endocrinopathies on the plasma amino acid profile of horses (2023)

Art

Hochschulschrift

Autor

Stöckle, Sabita Diana (WE 17)

Quelle

Berlin: Mensch und Buch Verlag, 2023 — IV, 49 Seiten

ISBN: 978-3-96729-217-6

Sprache

Englisch

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/40373

Kontakt

Pferdeklinik

Oertzenweg 19 b
14163 Berlin
+49 30 838 62299 / 62300
pferdeklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Horses suffering from laminitis usually have an underlying endocrine disease such as equine metabolic syndrome or a dysfunction of the pituitary gland (pitiutary pars intermedia dysfunction = PPID). Hyperinsulinaemia, which is caused by insulin-dysregulation, is currently assumed to be the triggering factor for laminitis. Insulin-dysregulation is present in equine metabolic syndrome and can also occur in horses suffering from PPID. It has already been shown that experimentally induced hyperinsulinaemia causes a change in the plasma amino acid profile of horses. This project was divided into 2 sub-projects. In the first sub-project, the plasma amino acid concentration of horses suffering from PPID was compared with that of healthy horses. Therefore, EDTA-plasma of horses from horses that were presented at the Equine Clinic of the Freie Universität Berlin for different reasons and required laboratory tests of blood anticoagulated with EDTA was asserved. This plasma was used to determine the basal ACTH concentration as well as the amino acid profile. Horses were considered to have PPID if the ACTH concentration was ≥ 100 pg/ml, i.e. they were considered to have PPID at any time. Horses were defined as healthy (nPPID) if the ACTH concentration was below 30 pg/ml, so they were considered healthy at any time point. Horses that received pergolide and whose ACTH concentration was ≤ 30 pg/ml were assigned to the PPIDrr group (PPID, ACTH in the reference range) and horses that received pergolide and whose ACTH concentration was ACTH ≥ 100 pg/ml were assigned to the PPIDarr group (PPID, ACTH above the reference range). A total of 93 horses were examined, 88 of them in the clinic and 5 in a private practice. Of these, 53 horses met the inclusion criteria (ACTH ≤ 30 pg/ml or ACTH ≥ 100 pg/ml). 25 horses were diagnosed as nPPID, 20 as PPID, 5 as PPIDrr and 3 as PPIDarr. No significant differences were present between the groups in terms of sex and breed. However, significant differences were found between groups with respect to feeding, age and ACTH concentration. Significant differences were present between nPPID and PPIDrr and PPID and PPIDrr with respect to feeding: All horses identified as PPIDrr were fed hay only, whereas the nPPID and PPID patients were fed concentrates (1 nPPID), mash (10 nPPID, 3 PPID) or grass (1 nPPID, 12 PPID) in addition to hay. One horse (nPPID) received only grass. In addition, horses suffering from PPID were significantly older than nPPID horses. There were no significant differences in age between the other groups. There were no significant differences in ACTH concentration between nPPID and PPIDrr. The ACTH concentration of PPID patients was significantly higher than in nPPID, PPIDrr and PPIDarr. In addition, PPIDarr horses had significantly higher ACTH concentrations than PPIDrr horses. The following significant differences were present in plasma amino acid concentrations: Arginine was significantly higher in PPIDrr than in PPID and nPPID, asparagine was significantly higher in PPID, PPIDrr and PPIDarr than in nPPID, citrulline was significantly higher in PPIDrr than in nPPID and PPID, cysteine was significantly lower in PPIDrr than in PPID, nPPID and PPIDarr and glutamine was significantly higher in PPID and PPIDarr than in nPPID. In the second part of the project, the plasma amino acid concentration of obese horses with and without chronic laminitis/lean horses suffering from chronic laminitis presented for a combined glucose-insulin-test (CGIT) as well as for a radiographic examination of the hooves. A total of 25 obese horses and two lean horses with recurrent laminitis underwent CGIT. Of the 27 horses that presented, five were non-insulin-dysregulated (obese), 14 were insulindysregulated and eight were insulin-dysregulated with radiographic evidence of chronic laminitis. Significant differences in resting amino acid concentrations were found between obese and insulin-dysregulated laminitis affected horses (citrulline, GABA, methionine). Furthermore, a significant difference between insulin-dysregulated horses with and without laminitis was detected with respect to the plasma GABA concentration. Overall, this project provides interesting approaches to develop further diagnostic tests, especially for the detection of horses at risk of laminitis, and possibly also for research into feed supplements.