Effect of dehydration and salt diet on dynamics of osmoregulatory hormones of ducks

This article presents results of a study examining the effects of prolonged dehydration and dietary sodium chloride on blood arginine vasotocin, prolactin, aldosterone, and corticosterone levels in ducks. The study was conducted on birds from two groups: a control group (low-salt diet + water) and an experimental group (highsalt diet +0.5% sodium chloride solution). After nine days of adaptation to the diet, significant differences were found between the groups in plasma osmolality, sodium and chloride concentrations, which corresponded to the level of sodium chloride intake. Long-term dehydration caused a progressive increase in plasma osmolality, sodium and chloride concentrations in all groups, with these values being significantly higher in the experimental group. Potassium concentration remained relatively stable in the high-sodium group during the dehydration period. The study revealed a significant increase in arginine vasotocin levels, which demonstrated a direct relationship with sodium chloride intake and a strong positive correlation with plasma osmolality (r=0.958-0.987). However, with dehydration, arginine vasotocin secretion reached a plateau, despite the continued increase in osmolality. Prolactin levels increased significantly, demonstrating a close correlation with plasma osmolality (r=0.911-0.995) and arginine vasotocin concentrations (r=0.932-0.957). In contrast to these hormones, aldosterone concentrations significantly decreased with high sodium chloride intake and demonstrated a weak negative correlation with osmolality and electrolytes. Corticosterone concentrations consistently increased in response to dehydration. These data indicate complex changes in osmoregulation and hormonal status in ducks during prolonged dehydration and varying levels of sodium chloride intake.