A. Sandin et al., EFFECTS OF DIFFERENTLY COMPOSED FEEDS AND PHYSICAL STRESS ON PLASMA GASTRIN-CONCENTRATION IN HORSES, Acta veterinaria Scandinavica, 39(2), 1998, pp. 265-272
Plasma gastrin concentrations were determined in 6 Standardbreds (4 ge
ldings and 2 mares) after 3 different meals consisting of unlimited am
ounts of hay (8-9 kg per horse), a restricted amount of hay (0.6 kg/10
0 kg bodyweight) and grain (0.2 kg/100 kg body-weight) in combination
or of grain alone (0.2 kg/100 kg body-weight). In another series of ex
periments the possible role of gastrin as a stress hormone was investi
gated. Plasma gastrin and cortisol concentrations were determined duri
ng fasting and compared with concentrations during hay feeding. In add
ition, gastrin and cortisol concentrations were determined before, dur
ing and after 2 kinds of physical exercise on a treadmill. Meal stimul
ation significantly increased the plasma gastrin concentration, irresp
ective of the meal composition. An immediate and large increase in pla
sma gastrin concentration was found when voluminous meals were given,
whereas a small meal evoked a later onset of gastrin release, suggesti
ng that gastric distention plays an important role in inducing gastrin
release during a meal. Meals consisting of grain seem to evoke a slow
er onset and then a more prolonged gastrin response than a hay meal, p
ossibly due to different emptying rates of the stomach. Nervous excita
tion may play a minor role in the activation of gastrin release in hor
ses. No experimental support was obtained for the idea that gastrin ac
ts as a stress hormone in the horse.