Juvenile psittacine environmental enrichment.

Environmental enrichment is of great import to the emotional, intellectual, and physical development of the juvenile psittacine and their success in the human home environment. Five major types of enrichment include social, occupational, physical, sensory, and nutritional. Occupational enrichment includes exercise and psychological enrichment. Physical enrichment includes the cage and accessories and the external home environment. Sensory enrichment may be visual, auditory, tactile, olfactory, or taste oriented. Nutritional enrichment includes variations in appearance, type, and frequency of diet, and treats, novelty, and foraging. Two phases of the preadult period deserve special enrichment considerations: the development of autonomy and puberty.

Investigations on feathering, feather growth and potential influences of nutrient supply on feathers' regrowth in small pet birds (canaries, budgerigars and lovebirds).

The aim of this study was to quantitate feathering in several companion birds. Besides the ratio of feathers to whole body mass, feather length as well as feather weight were of interest. Furthermore, data on feather loss and growth rates were estimated. In general, it could be observed that the proportion of feathers relative to body mass varied between 14 (canaries) and 7.4% (lovebirds). Feather losses (outside the moult period) amounted to an average of 6.65 (canaries), 8.98 (budgerigars), and 8.43 (lovebirds) mg/bird/day respectively or 37 (canaries), 20 (budgerigars), and 17 (lovebirds) mg/100 g body weight/day (values of interest in calculating of protein requirements for maintenance). In canaries, the average growth rate of the developing feathers amounted to 2 mm/day. In contrast to the onset of feather regeneration, the growth rate of new feathers leaving the follicle was not influenced by the supplements used here. The regeneration period (first measurable feather growth) of a plucked pinion can be used as an indicator and objective parameter to test potential nutritional influences. Parallel to the improvement of nutrient supply the rates of feather losses and also replacement increased, whereas the rates decreased when seed mixtures without any addition of minerals, sulphurous amino acids, and vitamins were fed.

Dietary glycine: its importance in growth and development of the budgerigar (Melopsittacus undulatus).

Birds have a high demand for the amino acid glycine due to its involvement in uric acid biosynthesis. Because the ability to synthesize glycine may be limited in the immature liver of young birds, glycine is usually considered to be semiessential in the diet of newly hatched chicks. This study investigated the effects of supplementary dietary glycine on growth and development in budgerigar chicks. Eighteen pairs of breeding budgerigars were randomly assigned to one of three dietary treatment groups. Each pair of birds was offered a seed-based diet and a rearing food that was used as the supplementation medium. One group received an unsupplemented rearing diet (2.7 g glycine/kg), whereas the remaining groups received diets supplemented with 15.0 and 30.0 g glycine/kg, respectively. Sixty-seven chicks were reared with records kept of growth and survival rates. A dietary glycine supplement tended to enhance the growth rate of budgerigar chicks, although this was not significant. There was no influence of diet on the rate of feather growth or the number of chicks that survived to adulthood. Follow-up measurements, conducted 1 y later, indicated that a dietary glycine supplement during development had long-term morphological effects. Bodyweight, tarsus length and beak width were all significantly greater in adult budgerigars that had received the highest level of glycine supplementation as chicks.

Comparative cell kinetics of avian growth plates.

New data on the cell kinetics of the cartilage growth plates in the chicken, budgerigar and rhea derived from studies with tritiated thymidine labelling are given. Quantitative histological measurements on growth plates from leg bones (tibiotarsus, tarsometatarsus and a phalangeal bone) in a further five species of birds are presented. Counts of flat cells and measurements of the average diameter of hypertrophic cells were made for each growth plate. These data are compared with values for the overall growth rates of the bones. The variation in sizes of hypertrophic cells was small and it is concluded that the largest factor in determining the growth rate of an avian bone is the size of the zone of flat cells.

The early ontogeny of ventilation and homeothermy in an altricial bird, Agapornis roseicollis (Psittaciformes).

The body temperature (Tb) of brooded Agapornis nestlings increased with age from 36.2 on the day of hatching to 38.9 degrees C on day 11.5, whereas the thermally neutral ambient temperature (Ta,n) decreased with age. The Tb of nestlings after a 20 min exposure to Ta approximately equal to 5 degrees C less than Ta,n increased from 31.9 on day 0.5 to 37 degrees C on day 11.5. At Ta,n both resting VO2 and mass-independent resting VO2 increased with age. Ventilation frequency (f) at Ta,n increased with age from 14.9 br/min on day 0.5 to 65.6 on day 11.5. This trend is the opposite of the allometric prediction based upon data from adult birds. At hatching, tidal volume (VT) was larger than predicted allometrically, whereas minute volume (VI) was smaller. After 20 min exposure to Ta 5 degrees C less than Ta,n, f, VT, and VI in nestlings 1 to 3 days old remained unchanged, but VO2 and oxygen extraction efficiency decreased. This mild cold-challenge caused a transient increase in VO2 of nestlings 5 to 8 days of age and 20 to 35% of adult mass. By the time the nestlings were 11.5 days old and had a mass 44% that of adults, their metabolic response to a mild cold-challenge was equal to that of an adult of the same mass. However, they were not capable of effective homeothermy over a wide range of Ta's.