RESEARCH ARTICLE Nitrogen Requirements of White‐Lipped Peccary (Mammalia, Tayassuidae) Sérgio L. G. Nogueira‐Filho, 1 * Rogério M. Borges, 1 Alcester Mendes, 1 and Carlos T. S. Dias 2 1 Laboratório de Nutrição de Animais Neo‐tropicais, Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil 2 Departamento de Ciências Exatas, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, São Paulo, Brazil A study was conducted to determine the protein requirement of the white‐lipped peccary (Tayassu pecari) performing a nitrogen (N) balance digestion trial. In a 4 Â 4 Latin square design, four adult captive male peccaries were fed four isoenergetic diets containing four different levels of N (13.3, 19.2, 28.7, and 37.1 g N/kg dry matter). After 15 days of adaptation, the total collection of feces and urine was carried out for five consecutive days. By regression analysis between N intake and N in feces and urine, the metabolic fecal nitrogen (MFN ¼ 3.1 g/kg of dry matter intake) and daily endogenous urinary N (EUN ¼ 91.0 mg/kg 0.75 ) were determined. Likewise, by regression analyses between consumption of nitrogen and the nitrogen balance [NBÀÀ ÀÀN consumed– (fecal N þ Urine N)] we estimated the daily requirement of 336.5 mgN/kg 0.75 . Therefore, if food intake is unrestricted, white‐ lipped peccaries require a minimum content in their diet of about 4.5% crude protein as percentage of dry diet. These values are similar to those found in frugivorous wild ruminants, which reinforces the proposition that peccaries have a digestive physiology nearer to that of ruminants than of domestic pigs. Furthermore, the low nutritional maintenance requirements for white‐lipped peccary may explain how this species thrive in the Neo‐tropical region eating predominantly palm‐fruits that normally have low crude protein contents. Zoo Biol. 33:320–326, 2014. © 2014 Wiley Periodicals, Inc. Keywords: animal nutrition; balance trials; comparative physiology; endogenous urinary nitrogen; metabolic fecal nitrogen; wildlife feeding INTRODUCTION The white‐lipped peccary (Tayassu pecari) is one of the three recognized living species of peccaries [Sowls, 1997]. This pig‐like mammal, despite being restricted to the Neo‐ tropical region, occupies a wide diversity of habitats from northern Argentina to south‐eastern Mexico, which include primarily humid tropical forests but also wet and dry grasslands and woodlands, xerophitic areas, tropical dry forests, and coastal mangroves [Keuroghlian et al., 2013]. This species is primarily frugivorous [Kiltie, 1981; Beck, 2006; Keuroghlian and Eaton, 2008; Desbiez et al., 2009], although it occasionally eats invertebrates and fish [Fragoso, 1999]. This ability to adapt to such diverse habitats, while mainly eating fruit that normally have low crude protein contents, could be explained by an anatomical/physiological characteristic of the species, the forestomach. Although the white‐lipped peccary does not ruminate, this species has a forestomach that represents up to 85% of the total digestive tract volume [Cavalcante‐Filho et al., 1997]. The fermenta- tion of dietary fiber occurs in this organ, which allows the species to digest forage like ruminants, resulting in the production of short chain fatty acids used in energy metabolism [Moraes, 1992; Comizzoli et al., 1997]. Besides Grant sponsor: Conselho Nacional de Desenvolvimento Científico e Tecnológico; grant number: 476033/2010‐1; grant sponsor: Coordena- ção de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/PNPD). Ã Correspondence to: Sérgio L. G. Nogueira‐Filho, Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Rod. Jorge Amado km 16, Ilhéus 45662‐900, Bahia, Brazil. E‐mail: slgnogue@uesc.b Received 22 November 2013; Revised 07 May 2014; Accepted 15 May 2014 DOI: 10.1002/zoo.21141 Published online 24 June 2014 in Wiley Online Library (wileyonlinelibrary.com). © 2014 Wiley Periodicals, Inc. Zoo Biology 33: 320–326 (2014)