Protein requirements of rainbow lorikeets, Trichoglossus haematodus

The natural diet of rainbow lorikeets is low in protein but in captivity th eir diets contain relatively high concentrations of protein. A nitrogen (N) balance study was carried out to determine the protein requirements of lor ikeets for maintenance. Five lorikeets were fed each of three diets, contai ning 3, 7 or 11 g egg white protein (100 g powdered diet)(-1) ('as is' basi s). After 10 days on a diet, lorikeets were placed in metabolism cages and N intakes and N excretion determined over three days. From the regression o f N excretion on N intake (y = 0.8664x + 0.032) endogenous nitrogen loss (E NL) was calculated as 32 mg N (kg body mass)(-0.75) day(-1) and the mainten ance N requirement as 240 mg N kg(-0.75) day(-1). The ENL is lower than tha t of other nectarivores but maintenance requirement is greater, indicating an unusually low digestibility for egg white protein (13.3%). Using a conse rvatively low digestibility of 4.5% for pollen, it can be calculated that 5 -6 g pollen (dry matter) per day would provide the 8 mg N day(-1) required by a 150-g lorikeet to replace ENL. By eating 150-200 mL nectar, about 30% of requirement could be obtained.