Effects of Dexamethasone Application in Growing Pigs on Hormones, N‐retention and Other Metabolic Parameters

Abstract

Many single effects of glucocorticoids are known but complex metabolic reactions in pigs in response to a glucocorticoid challenge were not reported. Seven pigs (mean weight 69 kg) with indwelling catheters were kept in metabolic crates. After a 7-day control period they were fed for 9 days with 0.4 mg dexamethasone (dex) per kg body weight daily, followed by another 9-day post-treatment period. Hormones and metabolic parameters were continuously determined in urine or blood plasma. Treatment significantly changed all parameters except non-esterified fatty acids. Cortisol decreased from 84.5 to 4.9 nmol/l, insulin-like growth factor I (IGF-I) from 17.5 to 10.8 nmol/l and aldosterone from 0.36 to 0.13 nmol/l. The N-retention decreased from 1.07 to 0.53 g/kg(0.75) and hydroxyproline from 2.97 to 1.05 mmol/day. An increase was found for urine volume (5.2 versus 13.6 l/day), urea-N (0.90 versus 1.43 g/kg(0.75)), allantoin (6.40 versus 8.75 mmol/day), glucose (3.9 versus 4.34 mmol/l) and insulin (6.21 versus 11.16 mU/l). In the post-treatment period IGF-I revealed a compensatory pattern (control period versus post-treatment period: 17.5 versus 22.9 nmol/l) whereas the other parameters were not significantly elevated. Data suggest that dex increased N-excretion both by inhibiting mitosis and resynthesis of proteins partly via a reduced collagen synthesis. Increased allantoin concentrations additionally pointed to increased apoptosis.

Administration of dexamethasone per os in finishing bulls. II. Effects on blood parameters used as indicators of animal welfare

“…Such treatment has been observed to lower the production of endogenous cortisol below physiological values in bovine species and this result is consistent with those obtained by Cagnasso et al (1987) in calves, by Lopes et al (2004) in growing pigs and by Allersmeier et al (2005) in horses using pour-on posology. Dexamethasone, acting as endogenous cortisol, inhibits hypothalamus and hypophysis activities (Sacher and McPherson, 2000), exerting a negative effect on ACTH secretion (Rijnberk and Mol, 1997).…”

Effects of two levels of feed allocation on IGF‐I concentrations and metabolic parameters in GnRH‐immunized boars

“…Urea in contrast did not differ between groups. Urea is an appropriate parameter to monitor protein degradation (Lopes et al, 2004) caused by glucocorticoids as the main regulator of protein breakdown. The catabolic effect of glucocorticoids is counteracted by testosterone, which was absent in both groups of immunocastrates and thus explains the increase of urea after second vaccination.…”