The use of internal markers to determine metabolizable energy and digestibility of diets in the African Grey parrot
Both acid-insoluble ash and acid-detergent lignin were evaluated as internal markers in digestibility studies with African Grey parrots (Psittacus erithacus erithacus). The markers were tested in a seed mixture, sunflower seed and a pelleted parrot diet.
Apparent metabolizable energy, corrected for nitrogen (N) retention (AMEn), nitrogen retention (NR), and apparent digestibility of dry matter, organic matter, crude protein and crude fat of a commercial seed mixture, sunflower seed, and a commercial pelleted parrot diet were determined using either the method of total collection of feed and excreta or using the marker technique. Both acid-insoluble ash (AIA) and acid-detergent lignin (ADL) presented unrealistic negative digestibility values for whole seed diets due to the higher concentration of marker found in the calculated feed intake than in the excreta. This study illustrates the necessity to determine nutrient concentration in feed refusals in digestibility studies with parrots due to the feeding habits of these birds. However, AIA as marker presented digestibility values that, although higher (P<0.05), showed similar or less variation than the method of total collection when applied to pelleted parrot diets in which feed refusals contain a similar nutrient concentration as the feed offered.
Title: The use of internal markers to determine metabolizable energy and digestibility of diets in the African Grey parrot (Psittacus erithacus)
Authors: Sales, J., Schutter, L. de, Janssens, G. P. J.