The influence of various lighting regimes and exogenous adrenal hormones upon blood glucose and electrolyte levels in chicks

The objectives of this study were to (1) determine rhythmic changes in blood glucose and electrolytes as influenced by different lighting regimes, (2) determine the influence of exogenous adrenal hormones and ACTH upon blood glucose and electrolyte levels of normally lighted birds, (3) compare blood glucose and electrolyte levels of non-treated birds from different lighting regimes to the blood levels of the treated, normally lighted birds, (4) make some conclusions regarding adrenal gland activity of the various experimental groups, using blood glucose and electrolyte levels as indicators of adrenal function. Groups of two-day old male and female chicks were subjected to lighting regimes of constant light, constant darkness, and normal light, i,e,, 12-hours light; 12-hours dark. Likewise, groups of both sex were exposed to normal illumination, but given daily dosages of adrenocortical hormones. The experimental period lasted 21 days. On day 22, blood samples were drawn at 4 hour intervals during a 24 hour period. Serum was extracted and stored via deep freeze until analysis could be performed. Serum samples were analyzed for chloride, bicarbonate, sodium, calcium, potassium, and glucose levels. This was accomplished by means of a sequential multiple analyzer (SMA-660) machine and an atomic absorption-emission spectrophotometer. An attempt was made to compare the data of the hormone treated groups to that of the various light regime groups. The results indicated that constant light and constant darkness stimulated adrenal function. This was evidenced by the fact that there was an increased retention of sodium and bicarbonate, and an increased excretion of calcium in birds exposed to constant light or darkness. Also, it appeared that normal circadian electrolyte and glucose rhythms were altered by constant light and darkness. It was also apparent that sexes responded differently to the various treatments.