White rhinoceroses are well known for their two horns, which have resulted in many of these animals being #selleck chemicals randurls[1|1|,|CHEM1|]# killed by poachers for their horns. Now the white rhinoceros is on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species [2]. The white rhinoceros once roamed much of sub-Saharan Africa, but today is on the near threatened list with less than 20,200 of these animals remaining in the wild [2]. One of the prerequisites to better protect

these endangered animal species is to better understand their digestive physiology and nutritional requirements. Given the importance of the gut microbiota in herbivorous animals, little is known about the hindgut microorganisms in the white rhinoceros. Methanogenic archaea, also called methanogens, exist widely in the GIT of many vertebrates and invertebrates [3]. Methanogens can use a number of different substrates, such as hydrogen, formate, acetate, methanol, and methlyamines, to reduce carbon dioxide to methane during the normal fermentation of feed [4], and studies on ruminants have shown that the production of enteric methane results in loss of gross energy available to the host [5, 6]. Methanogens have been isolated from various animals [7, 8] and several studies using culture-independent methods, including 16S rRNA gene clone

library analysis, have provided some useful data on many the diversity and abundance of methanogens in rumen [9–12]. In other hindgut fermenters, such as humans and https://www.selleckchem.com/products/pci-32765.html pigs, the diversity and density of methanogens in the human colon were different among obese and lean,

or post-gastric-bypass, individuals [13]. Moreover, the structure of fecal methanogens appears to differ among different pig breeds [14, 15]. These studies indicated that methanogen diversity in the GIT may be host species-specific and, or, function-dependent. Therefore, we hypothesize that the methanogens present in the white rhinoceros may have a unique community structure and composition than those from other herbivores, which have been studied to date. The objectives of the present study are to elucidate the molecular diversity and community structure of methanogens in the hindgut of the white rhinoceroses using 16S rRNA gene clone library analysis. Methods Sample sources and processing All animals were legally transported from South Africa into Yunnan Wild Animal Park in China as ornamental animals in July, 2010 under permission of the State Forestry Bureau of China, and were managed according to the guidelines of animal care and use approved by the Chinese Authority. Seven adult white rhinoceroses (4 males and 3 females), aged from 6 to 8 years old, were selected as experimental animals. Feed consisted of pellets, apple, carrot, fresh forage/alfalfa and alfalfa hay with a ratio as 10:5:10:80:10.