Maintenance nitrogen requirements of adult female ostriches (Struthio camelus)

Abstract

Successful ostrich farming requires knowledge of the nutritional needs of the birds. While much information is available on the nutritional value of various feed ingredients fed to ostriches, there is little known about their specific nutrient requirements. In this study, we measured the maintenance nitrogen requirements (MNR) of ostriches by nitrogen balance. We predict, based on the previous analysis of nitrogen requirements of various species of birds, that ostriches would have a MNR of 13.6-19.1 g N/day and a total endogenous nitrogen loss (TENL) of 2.8-5.1 g N/day. Three adult female ostriches were fed five pelleted diets containing 0.6-2.3% N [4-14.6% crude protein (CP)], 17.5 kJ/g gross energy (11.4 kJ/g ME) and 30% neutral detergent fibre. Each dietary trial consisted of a 10-day adaptation period, followed by a 5-day total excreta collection period. Body mass (109 ± 3 kg) and metabolizable energy intake (20.5 ± 0.7 MJ/day) were unaffected by dietary nitrogen levels. After correcting for excreta nitrogen losses during drying, MNR was calculated to be 481 mg N/kg(0.75) /day or 16.2 g N/day (100 g CP/day), and TENL as 310 mg N/kg(0.75) /day or 10.5 g N/day. Failure to correct for the 10.9 ± 4.1% average N losses during drying would underpredict the 'true' MNR by 35% and TENL by 46%. Our estimate for MNR of ostriches predicts a dietary requirement of 6.7% protein. Our estimate of TENL was nearly twice that predicted, possibly reflecting the high fibre content of their diet.

Nutrient acquisition across a dietary shift: fruit feeding butterflies crave amino acids, nectivores seek salt

“…We did not measure butterflies' physiological requirements for sodium or amino acids, so can only speculate about demand. However, changes in nutritional requirements have been observed in other dietary shifts: for example, in birds, frugivorous, nectivorous, and herbivorous species have lower dietary nitrogen requirements than granivorous, omnivorous, and carnivorous species, allowing them to succeed in more nitrogen-limited environments (Bennett et al 2012). The dietary switch from nectar to fruit could be related to a more nitrogen-intensive life history.…”

Comparative digesta retention patterns in ratites

“…Note, however, that the results on retention times in those 2 species for which previously published data exist, the Ostrich and the Emu , Swart et al 1993, Fritz et al 2012, correspond to the findings of our study, and that any limitations affected all species equally, making interspecific comparisons possible. In particular, rather than relying on fecal collection from enclosure floors (even though covered by carpets), the use of a harness system as described by Bennett et al (2012) would have been preferable. Note that effects of differences in particle size reduction, which may occur on natural foods due to the scaling with body mass (Fritz et al 2011), did not affect the results of the present study because a common diet was used that had been finely ground before pelleting.…”

Current perspectives in avian nutrition: domestic animal models and their role in conservation management

“…5). Additionally, nectivorous species often require proportionally lower amounts of protein nitrogen (Bennett et al 2012), fat (Pryor 2003) and some micronutrients, in particular calcium (Peaker 1990), compared with omnivores, carnivores and hindgutand foregut-fermenting herbivores, a trend that is probably similar for lipid requirements of nectivores, frugivores and granivores alike (Table 1). Similarly, considerably less dietary iron is required by frugivorous species such as birds of paradise (Helmick et al 2011), mynahs (Mete et al 2003), toucans and starlings (Sheppard & Dierenfeld 2002) than typical herbivores and omnivores (Table 1).…”