Insulin responses to acute glucose infusions in Buša and Holstein-Friesian cattle breed during the peripartum period: Comparative study

Abstract

The aim of this study was to compare insulin responsevness to acute glucose infusion in cows of Holstein Friesian (HF) and Buša breeds during the peripartal period. Eight cows per each group (HF and Buša), were chosen. At day 7 prior to calving (ante partum) and day 14 after calving (post partum) animals were subjected to a glucose tolerance test (GTT). Blood samples were taken immediately before infusion and 15, 30, 60, 120 and 180 min thereafter. Glucose and insulin concentrations were measured in each blood sample, while BHBA and NEFA were measured only in samples taken before the infusion. QUICKY an indicator of insulin resistance in cows was calculated. Basal glycemia did not significantly differ between the breeds. Basal insulinemia was significantly higher in Buša than in HF cows in both examined periods (p lt 0.001, respectively). Basal NEFA levels tended (p=0.06) to be higher in Buša cows compared with those of HF ante partum, and was significantly higher (p lt 0.001) post partum. Basal BHBA was significantly lower in Buša than HF cows in both examined periods (p lt 0.01; p lt 0.001). QUICKI was significantly lower in Buša compared to HF cows both ante partum and post partum periods (p lt 0.001, respectively). Glycemia determined during GTT were higher in Buša than HF cows, both ante partum and post partum, but significantly starting from minute 15 ante partum i.e. minute 30 post partum. Insulinemia determined during GTT was significantly lower at min 15, and significantly higher starting from min 90 in Buša than HF cows, both ante partum and post partum. Results obtained in this study indicate on difference in insulin responsevness to acute glucose infusion between the examined breeds, which is probably a consequence of the difference in the degree of negative energy balance rather than of selection on high milk production. Namely, decreased insulin tissues sensitivity and decreased insulin responsiveness in Buša compared to HF cows is probably the consequence of inadequate energy intake from alimentary sources which leads to enhanced usage of energy from body reserves.

Cilj ovog rada je bio da se uporedi insulinski odgovor na akutnu infuziju glukoze kod krava holštajn frizijske rase (HF) i buše tokom peripartalnog perioda. Za ispitivanja je odabrano po osam krava obe rase. Sedam dana pre teljenja (ante partum) i 14 dana posle teljenja (post partum), životinje su podvrgnute testu tolerancije na glukozu (GTT). Uzorci krvi su uzimani neposredno pre aplikacije glukoze, kao i 15, 30, 60, 120 i 180 minuta kasnije. U svakom uzorku su određivane koncentracije glukoze i insulina, dok su koncentracije BHBA i NEFA određivane samo u uzorcima uzetim pre infuzije. Kao pokazatelj insulinske rezistencije kod krava je izračunat QUICKI. Bazalna vrednost glikemije se nije značajno razlikovala između krava različitih rasa, dok je vrednost bazalne insulinemije bila značajno viša kod krava rase buša nego HF u oba ispitivana perioda (p lt 0,001, pojedinač no). Bazalna vrednost koncentracija NEFA je imala tendenciju (p = 0,06) povećanja kod krava rase buša u odnosu na HF ante partum, a bila je značajno viša (p lt 0,001) post partum. Bazalna vrednost koncentracije BHBA je bila značajno niža kod krava rase buša nego kod HF tokom oba ispitivana perioda (p lt 0,01; p lt 0,001). QUICKI je bio značajno niži kod krava rase buša u odnosu na HF kako ante partum tako post partum (p lt 0,001, pojedinačno) ukazujući na manju senzitivnost tkiva na insulin kod krava rase buša. Koncentracija glukoze je tokom izvođenja GTT bila viša kod krava rase buša u odnosu na HF, kako ante partum tako i post partum, s tim da je ova razlika bila značajna počevši od 30. minuta testa ante partum i 15. minuta testa post partum. Koncentracija insulina je tokom izvođenja testa bila značajno niža 15. minuta, a značajno viša počevši od 90. minuta testa kod krava rase buša u odnosu na HF rasu kako ante partum tako i post partum. Razultati dobijeni u ovom radu ukazuju na razliku u insulinskom odgovoru na akutnu aplikaciju glukoze između dve ispitivane rase krava, a koja je najverovatnije posledica razlike u balansu energije, a ne selekcije na visoku proizvodnju mleka. Naime, smanjena senzitivnost tkiva na insulin i smanjeni insulinski odgovor krava rase buša u odnosu na HF je verovatno posledica smanjenog unošenja energije iz alimentarnih izvora zbog čega se u većem stepenu koriste izvori energije iz telesnih depoa.