Plasma adrenocorticosteroid levels in protein and energy restricted pigs

Pigs (Yorkshire) were subjected to protein-energy malnutrition in the following manner: 3- or 4-week-old pigs from control dams were fed a control diet (18% protein), an energy-restricted diet (18% protein), or a low protein diet (6% and 3% protein) for 8 weeks. Energy restriction was achieved by feeding the control diet in amounts that allowed some growth, but only to an extent equal to the low protein diet being matched. After the restriction period, all pigs were fed the control diet for another 8 weeks. Blood samples were collected at intervals from the superior vena cava. Plasma samples were analyzed for corticosteroids in all groups and for free cortisol in the controls and 3% protein groups. No significant differences were found for total plasma corticosteroids among all groups. Free cortisol was found significantly higher in the 3% group compared to the controls. An ACTH test was performed with depleted and recovered pigs of the 3% protein group and controls. No differences were found among controls, depleted and recovered pigs.