Abstract:[Objectives] After long-term natural selection, the Bactrian Camel (Camelus bactrianus) has many special biological characteristics, such as strong thirst tolerance, hunger tolerance and the ability to adapt to bad weather. Nesfatin-1 is a peptide composed of 82 amino acids. It is derived from the protein hydrolysis of its precursor NUCB2 in prohormone convertases (PCS) at Lys 83 - Arg 84 site. It can regulate the efficiency of energy metabolism and inhibit appetite. To study the distribution and expression of NUCB2/Nesfatin-1 in Bactrian camels, in order to explore whether Bactrian camels have a unique way of energy metabolism and whether it is related to the absence of metabolic diseases. [Methods] The hapten polypeptide of specific epitope of Bactrian camel NUCB2/Nesfatin-1 protein was synthesized by chemical synthesis method. The hapten was coupled with keyhole limpet hemocyanin (KLH) by maleimide method, and polyclonal antibody against single antigenic epitope of NUCB2/Nesfatin-1 protein was prepared by immunizing animals, Western blot was used to detect the expression of NUCB2/Nesfatin-1 protein in the hypothalamus (arcuate nucleus, solitary tract nucleus, ventromedial nucleus), anterior peak fat, posterior peak fat, stomach (tissue around gastric fundus gland), duodenum, jejunum, ileum, cecum, colon, rectum, pancreas, liver and abdominal adipose tissue of Bactrian camel. The expression of NUCB2/Nesfatin-1 mRNA in the above tissues o was also detected by fluorescence quantitative PCR. T-test analysis was used to analyze the results by using graphpad prism 5.0 software. [Results] The synthesized Bactrian Camel NUCB2/Nesfatin-1 protein had few polypeptide heteropeaks at specific epitopes, and its purity was calculated to be more than 95%. The mass charge ratio [M + 4H]4+ and [M + 3H]3+ of the polypeptide was in line with its expectation (Fig. 1, 2). The titer of the polyclonal antibody against NUCB2/Nesfatin-1 protein determined by indirect ELISA was 5.12 ′ 105, and the polyclonal antibody was successfully prepared (Fig. 4). The prepared polyclonal antibody of NUCB2/Nesfatin-1 was used to detect the distribution of NUCB2/Nesfatin-1 protein various tissues and organs mentioned above. It was significantly expressed in adipose tissue and pancreas of Bactrian Camel (Fig. 7, 8). The distribution of NUCB2/Nesfatin-1 mRNA in Bactrian camel was detected by fluorescence quantitative PCR. It was found that the gene was expressed in the detected tissues, especially in abdominal fat and liver tissues (Fig. 9). [Conclusion] In this study, a specific antibody against Bactrian Camel NUCB2/ Nesfatin-1 protein was successfully prepared by analyzing antigen epitopes and synthesizing peptides, and the antibody has high titer and strong specificity. The distribution of NUCB2/Nesfatin-1 in Bactrian Camels was detected at the protein level by the successfully prepared specific antibody, and then the distribution of NUCB2/Nesfatin-1 in Bactrian Camels was detected at mRNA level by fluorescence quantitative PCR. Through the analysis of the results, it is found that NUCB2/Nesfatin-1 is highly expressed in the peripheral adipose tissue, and it may play a role in inhibiting appetite in the regulation of thirst and hunger tolerance mechanism of Bactrian camel, so that Bactrian Camel can endure long-term hunger. It is speculated that NUCB2/Nesfatin-1 protein may inhibit the differentiation of adipocytes, promote the hydrolysis of lipid droplets in adipocytes and provide energy for the body in Bactrian Camel. Its specific function in adipocytes needs our further study.