Response of newly hatched chicks to inanition.

Newly hatched chicks were kept for up to 48 hours without food and water and compared with a control group of chicks given access to food and water within six hours of hatching. The deprived chicks progressively lost body water and developed increases in plasma total protein concentration consistent with a decrease in plasma volume. They demonstrated a stronger motivation to drink and drank more when offered water, suggesting that they had become dehydrated. There was evidence, however, that normally access to food was necessary to initiate drinking. The deprived chicks continued to rely on fat metabolism to supply their energy needs whereas the fed birds showed rapid reductions in circulating levels of beta-hydroxybutyrate and increases in plasma glucose and liver glycogen concentrations, indicating a change to carbohydrate-orientated energy metabolism. The deprived chicks lost weight at an average of 0.14 g/hour and weighed 16.5 g less than the fed chicks after 48 hours.