Estimation of protein requirement for maintenance in adult parrots by determining inevitable N losses in excreta
Especially in older pet birds, an unnecessary overconsumption of protein - presumably occurring in human custody - should be avoided in view of a potential decrease in the excretory organs' (liver, kidney) efficiency.
Inevitable nitrogen (N)-losses enable the estimation of protein requirement for maintenance, because these losses have at least to be replaced to maintain N equilibrium. To determine the inevitable N losses in excreta of adult amazons (Amazona spp.), a frugivor-granivorous avian species from South America, adult amazons (n = 8) were fed a synthetic nearly N-free diet (in dry matter; DM: 37.8% starch, 26.6% sugar, 11.0% fat) for 9 days. Throughout the trial, feed and water intake were recorded, the amounts of excreta were measured and analysed for DM and ash content, N (Dumas analysis) and uric acid (enzymatic-photometric analysis) content. Effects of the N-free diet on body weight (BW) and protein-related blood parameters were quantified and compared with data collected during a previous 4-day period in which a commercial seed mixture was offered to the birds. After feeding an almost N-free diet for 9 days, under the conditions of a DM intake (20.1 g DM/bird/day) as in seeds and digestibility of organic matter comparable with those when fed seeds (82% and 76% respectively), it was possible to quantify the inevitable N losses via excrements to be 87.2 mg/bird/day or 172.5 mg/kg BW0.75/day. Assuming a utilization coefficient of 0.57 this leads to an estimated protein need of approximately 1.9 g/kg BW0.75/day (this value does not consider further N losses via feathers and desquamated cells; with the prerequisite that there is a balanced amino acid pattern).
Title: Estimation of protein requirement for maintenance in adult parrots (Amazona spp.) by determining inevitable N losses in excreta
Authors: C. Westfahl, P. Wolf and J. Kamphues