Endocrine and metabolic profile in Holstein and red Holstein heifers during peripartal period

Abstract

The aim of this stady was to examine the relationship between triiodothyronine (T3), thyroxin (T4), insulin-like growth factor-I (IGF-I) and blood serum liver function biomarkers concentrations in Holstein and Red Holstein heifers during the peripartal period. In the first experimental group (I) were heifers of Holstein Friesian breed (n=10), and in the second experimental group (II) were Red Holstein heifers (n=10). Blood samples were taken from the vena coccygea three times during the short peripartal period (5 days before delivery, at delivery and 5 days after delivery), and blood serum samples were separated after spontaneous coagulation. Blood serum T3, T4 and IGF-I concentrations were determinated using radioimmunoassay (RIA). Blood serum concentrations of glucose (G), total protein (TP), albumin, (Alb), urea, total bilirubin (tBil) and aspartate aminotrasferase (AST) were determined using commercial ELISA kits. The statistical significance between means was determined using Student t-test. Blood serum T3 concentration in Group II was significantly lower after delivery, and T4 concentration was significantly higher before delivery (p lt 0.05), compared to Group I. Mean blood serum IGF-I concentrations between the two experimental groups were not significantly different at all time intervals. Relationships between the determined hormones showed a median positive correlation between T3, and T4 (r=0.74) in Group I and highly positive correlation in Group II (r=0.81). Blood serum thyroid gland hormones and IGF-I concentrations in healthy heifers during peripartal period vary considerably, the lowest values being determined immediately after calving in both experimental groups. Blood serum G, TP, Alb and urea concentrations were significantly higher in Group I at all investigated time intervals. Blood serum tBil concentration was significantly higher after partus in Group I (11.02 ± 3.33 : 8.49 ± 3.35 μmol/L, Group I vs. II, respectively), and AST activity was not significantly different at all intervals.

Cilj ovih istraživanja je bio određivanje koncentracije triijodtironina (T3), tiroksina (T4), insulinu sličnog faktora rasta-I (IGF-I) i biomarkera, pokazatelja funkcionalnog stanja jetre u krvnom serumu dva varijeteta junica Holštajn rase u peripartalnom periodu. Prvu eksperimentalnu grupu (I) činile su junice crno belog holštajna (n=10), a drugu grupu (II) junice crvenog holštajna (n=10). Krv za analize je uzimana iz repne vene, tri puta u peripartalnom periodu (5 dana pre partusa, na dan partusa i do 5 dana posle partusa), a krvni serum je odvajan nakon spontane koagulacije. U krvnom serumu je radioimunološkom metodom (RIA, INEPZemun) određivanja koncentracija trijodtironina (T3), tiroksina (T4) i insulinu sličnog faktora rasta-I (IGF-I). Koncentracija glukoze (G), ukupnih proteina (TP), albumina, (Alb), ureje, ukupnog bilirubina (tBil) i aktivnost aspartat aminotrasferaze (AST) je određivana upotrebom komercijalnih ELISA kitova. Statistička značajnost razlika srednjih vrednosti ispitivanih endokrinih i metaboličkih parametara je određena Studentovim t-testom. Dobijeni rezultati ukazuju na vrlo različite koncentracije hormona štitne žlezde u krvnom serumu junica oba varijeteta holštajna pre i posle partusa. Koncentracija T3 je bila statistički značajno niža u grupi II nakon partusa, a T4 značajno viša pre partusa (p lt 0.05) u odnosu na nivo hormona u grupi I. Za prosečne vrednosti koncentracija IGF-I, između isptivanih grupa nije ustanovljena statistički značajna razlike ni u jednom od tri perioda ispitivanja. Utvrđena je srednje pozitivna korelacija između koncentracije T3 i T4 (r=0,74) u krvnom serumu junica grupe I, i vrlo visoka pozitivna korelacija u grupi II (r=0,81). Koncentracija TP, Alb i ureje bila je statistički značajno viša kod junica grupe I u sva tri perioda ispitivanja. Nivo tBil u krvnom serumu je takođe bio povišen kod junica grupe I u sva tri perioda ispitivanja, ali su statistički značajne razlike između srednjih vrednosti ustanovljene samo u periodu nakon partusa. Aktivnost AST u krvnom serumu junica oba varijeteta značajno je varirala u svim periodima ispitivanja i nisu ustanovljene statistički značajne razlike između srednjih vrednosti.