The Canarian Camel: A Traditional Dromedary Population

The one-humped camel: The animal of future, potential alternative red meat, technological suitability and future perspectives

The 2020 world population data sheet indicates that world population is projected to increase from 7.8 billion in 2020 to 9.9 billion by 2050 (Increase of more than 25%). Due to the expected growth in human population, the demand for meats that could improve health status and provide therapeutic benefits is also projected to rise. The dromedary also known as the Arabian camel, or one-humped camel ( Camelus dromedarius), a pseudo ruminant adapted to arid climates, has physiological, biological and metabolic characteristics which give it a legendary reputation for surviving in the extreme conditions of desert environments considered restrictive for other ruminants. Camel meat is an ethnic food consumed across the arid regions of Middle East, North-East Africa, Australia and China. For these medicinal and nutritional benefits, camel meat can be a great option for sustainable meat worldwide supply. A considerable amount of literature has been published on technological aspects and quality properties of beef, lamb and pork but the information available on the technological aspects of the meat of the one humped camel is very limited. Camels are usually raised in less developed countries and their meat is as nutritionally good as any other traditional meat source. Its quality also depends on the breed, sex, age, breeding conditions and type of muscle consumed. A compilation of existing literature related to new technological advances in packaging, shelf-life and quality of camel meat has not been reviewed to the best of our knowledge. Therefore, this review attempts to explore the nutritional composition, health benefits of camel meat, as well as various technological and processing interventions to improve its quality and consumer acceptance. This review will be helpful for camel sector and highlight the potential for global marketability of camel meat and to generate value added products.

Surveillance and control of Trypanosoma evansi in the canary Islands: A descriptive analysis

This study examines the occurrence of Surra, a disease caused by Trypanosoma evansi, in camels in the Canary Islands. The 1997 detection of T. evansi in camels in the Canary Islands led to the implementation of an initial control program, resulting in a decrease in prevalence. Following an outbreak in 2014, and due to the impossibility of eradicating it using the conventional measures, a lazaret was set up to separate positive and suspicious animals, in addition to the control measures previously implemented. Stomoxys calcitrans was the only vector captured, and no other animals tested were found to be positive for T. evansi. In November 2019, the last camels that tested serologically positive were detected; however, since February 2018, no camels that tested positive for PCR have been found in the farms were the outbreak was detected, suggesting that the sanitary measures implemented are adequate. The duration of the outbreak control and potential eradication for the disease has yet to be established. This study provides evidence to facilitate the control of African Animal Trypanosomosis in endemic areas of the world, which may contribute to revise the World Organization for Animal Health (WOAH) protocol to implement recommendations of surveillance and control strategies for animal Trypanosomosis in camels.

Haematological and biochemical blood reference values for Canary Island camels (Camelus dromedarius), an endangered dromedary species

The purpose of this research was to develop reference values for haematological and biochemical variables in the Canary camel breed (Camelus dromedarius). 114 clinically healthy dromedary camels were assessed. Age, sex, and pregnancy status was also recorded. The reference range for red blood cells (RBCs) was 8.45 - 13.65 X10⁶/µL, haemoglobin (HGB) was 10.61 - 15.29 g/dL, packed cell volume (PCV) was 19.93 - 32.51 %, and white blood cells (WBCs) 7.35 - 18.36 X10³/µL. A correlation was established between the haemoglobin concentration (HGB) (g/dl) and packed cell volume (PCV) obtaining a linear regression (HGB = 0.31 PCV + 4.67). Young animals had higher RBC and WBC values than adult animals. Additionally, blood urea nitrogen (BUN), phosphorus, calcium, albumin/globulin (A/G) ratio, alkaline phosphatase, cholesterol, and lipase were higher in young animals compared with adults. Female dromedary camels showed higher values for the three main variables: RBC, HGB and PCV, but no differences between sexes were detected in the biochemical variables results. The WBC count was higher in non-pregnant females than in pregnant animals. These results provide references values for the Canary camel breed and may contribute to the understanding of differences in 18 haematological and biochemical parameters in dromedary camels with a potential impact in health and welfare for this species.

Tunisian camel casein gene characterization reveals similarities and differences with Sudanese and Nigerian populations

Milk is a primary protein source that has always played a role in mammalian health. Despite the intensification of research projects on dromedary and the knowledge of the genetic diversity at the casein loci, the genetic structure of the Tunisian camel population still needs exploration. This study sought to determine the genetic diversity of 3 casein gene variants in 5 Tunisian camel ecotypes: c.150G>T at CSN1S1 (α_S1-casein), g.2126A>G at CSN2 (β-casein), and g.1029T>C at CSN3 (κ-casein). The obtained results were compared with data published on Sudanese and Nigerian camels to establish the level of differentiation within and between populations. A total of 159 blood samples were collected from 5 Tunisian camel ecotypes and the extracted DNA was genotyped by PCR-RFLP. A streamlined genotyping protocol was also developed for CSN3. Results indicated that allele T was quite rare (0.06) at CSN1S1 for all ecotypes. Minor allele frequency was found for G (0.462) in CSN2 except for Ardhaoui Medenine ecotype who deviated from the average CSN2 allele frequency of the total population. Allele C showed minor allele frequency of 0.384 in CSN3. Among the Tunisian population, GAT (0.343) was the most represented haplotype in all ecotypes except for Ardhaoui Medenine, where GGC (0.322) was the most frequent one. Significant differences in heterozygosity and local inbreeding were observed across the Tunisian, Sudanese, and Nigerian populations, although the global fixation index indicated that only 2.2% of the genetic variance is related to ecotype differences. Instead, phylogenetic analysis revealed a closer link between the Tunisian and Sudanese populations through a clade subdivision with 3 main branches among the ecotypes. This study represents the first attempt to understand casein gene variability in Tunisian camels; with further study, milk traits and genetic differentiation among populations can be associated with the history of camel domestication.

Aspects of Molecular Genetics in Dromedary Camel

Dromedary camels are unique in their morphological and physiological characteristics and are capable of providing milk and meat even under extreme environmental conditions. Like other species, the dromedary camel has also benefitted from the development of the molecular genetics to increase the knowledge about different aspect in camel genetics (genetic variation, molecular marker, parentage control, gene of interest, whole genome, dating…etc.). In this paper we review the different molecular genetic technics used in this particular species and future prospects. Dromedary genetic studies started in the end of the 1980s with phenotypic evaluation and the attempts to highlight the protein and biochemical diversity. In the 2000s, with the development of molecular markers such as microsatellites, genetic diversity of different types in several countries were estimated and microsatellites were also used for parentage control. In terms of genetic characterization, microsatellites revealed a defined global structure, differentiating East African and South Arabian dromedaries from North African, North Arabian, and South Asian individuals, respectively. Also, mitochondrialDNA sequence analysis of ancient DNA proved to be crucial in resolving domestication processes in dromedaries. Ancient and modern DNA revealed dynamics of domestication and cross-continental dispersion of the dromedary. Nuclear SNPs, single nucleotide polymorphisms changes that occur approximately each 1000 bps in the mammalian genome were also applied in some studies in dromedary. These markers are a very useful alternative to microsatellites and have been employed in some studies on genetic diversity and relevant phenotypic traits in livestock. Finally, thanks to the use of Next Generation Sequencing (NGS) the whole-genome assemblies of the dromedary (Camelus dromedarius) and a work to establish the organization of the dromedary genome at chromosome level were recently published.

A tool for functional selection of leisure camels: Behaviour breeding criteria may ensure long-term sustainability of a European unique breed

Livestock selection for desirable temperament traits still remains disregarded for minor productive species, such as camels. Despite dromedary camels from Canary Islands were at once polyvalent, current major functionality for this unique European recognised breed is limited to tourism-oriented interactive experiences. The conservation of this endemic breed implies the immediate enforcement of selective breeding programmes by including behavioural functional traits as genetic selection criteria. With this purpose, we evaluated the suitability of a practical proposal to qualitatively and quantitatively evaluate camel behaviour performance to be applied in breeding programmes for the improvement of camel personality dimensions. One-hundred thirty-one respondents enjoying a camelback leisure riding during high season in Southern Spain were asked to voluntarily fulfill an on-site questionnaire just after the tourist ride concluded. Eleven behaviour criteria were rated on a 5-point Likert-type scale by each respondent for the camel they had ridden on. Generalized Procrustes Analysis revealed that a general consensus between participants for dromedary behavioural features were reached, more substantial for those expressions reflecting agitation and/or indifference towards interaction with human. Moreover, the variability in animal behaviour patterns could be attributed to camel sex- and age-related differences. Mid- to long-term sustainability of Canarian camels may rely on the ability of involved stakeholders to adapt leisure opportunities to customer demands and expectations. Hence, those camel behavioural features with a conditioning potential of overall participants satisfaction, may become potential objective selection criteria candidates. Consequently, camel functional selective breeding may ensure camel breed preservation and sustainable protection based on leisure activities.

Genetic Diversity and Population Structure of Dromedary Camel-Types

The dromedary camel is a unique livestock for its adaptations to arid-hot environments and its ability to provide goods under extreme conditions. There are no registries or breed standards for camels. Thus, named camel populations (i.e., camel-types) were examined for genetic uniqueness and breed status. Camel populations are generally named based on shared phenotype, country or region of origin, tribal ownership, or the ecology of their habitat. A dataset of 10 Short-Tandem Repeat markers genotyped for 701 individual camels from 27 camel-types was used to quantify genetic diversity within camel-types, compare genetic diversity across camel-types, determine the population genetic structure of camel-types, and identify camel-types that may represent true breeds. Summary statistics (genotyping call rate, heterozygosity, inbreeding coefficient FIS, and allelic frequencies) were calculated and population-specific analyses (pairwise FST, neighbor-joining tree, relatedness, Nei's genetic distance, principal coordinate analysis [PCoA], and STRUCTURE) were performed. The most notable findings were 1) little variation in genetic diversity was found across the camel-types, 2) the highest genetic diversity measure was detected in Targui and the lowest was in Awarik, 3) camel-types from Asia (especially the Arabian Peninsula) exhibited higher genetic diversity than their counterparts in Africa, 4) the highest DeltaK value of population structure separated camel-types based on geography (Asia vs. Africa), 5) the most distinct camel-types were the Omani, Awarik, and the Gabbra, 6) camel-types originating from the same country did not necessarily share high genetic similarity (e.g., camel-types from Oman), and 7) camel-type names were not consistently indicative of breed status.

Camel Genetic Resources Conservation through Tourism: A Key Sociocultural Approach of Camelback Leisure Riding

Camels are exotic elements, which can be comprised within adventure travel companies promoting ecotourism activities. Such recreations contribute to sustainable livelihoods for local communities and educational empowerment towards nature and its conservation. At present, some local camel breeds' survival reduces to this animal-based leisure industry and its reliability to perform and promote customized services accurately. By conducting an on-site questionnaire to customers participating in camelback riding tours, we assessed the motivational factors affecting participation, satisfaction, and loyalty in this tourism segment that may have made it socially differentiated. The sixfold combination of staff performance, culture geography, diverse and humane close interaction, camel behavior and performance, sociotemporal context, and positive previous experience involves the elemental dimensions that explain customer satisfaction and return intention probability within this entertainment business. Customer knowledge is essential for stakeholders to build personalized riding experiences and align profits with environmental sustainability and biodiversity mainstream concerns into their everyday operations. In turn, domestic camel tourist rides could be managed as a viable path to nature conservation by helping endangered local breeds to avoid their functional devaluation and potential extinction.

Utilization of microsatellite markers in genotyping of Saudi Arabian camels for productivity and conservation

Camels are considered as integral and notable components of the heritage of the Kingdom of Saudi Arabia. Genetic variabilities within and among four camel populations in Saudi Arabia were evaluated using 21 simple sequence repeat (SSR) loci of 122 unrelated individuals, including three indigenous breeds [Humur (HA), Zurg (ZR), Shuguh (SG)] and one exotic breed [Sudanese (SN)]. Nineteen SSR markers generated multilocus fingerprints with a total of 225 alleles, a range of 4–23 alleles per locus, and an average of 9, 7, 7, and 6 alleles per locus in HA, ZR, SG, and SN populations, respectively. The mean multilocus FSTvalue (0.034 ± 0.005) showed non-significant population differentiation. Mean observed heterozygosity values were 0.908 for HA, 0.860 for ZR, 0.919 for SG, and 0.887 for SN, which were higher than the expected heterozygosity. An excess of heterozygotes was observed, suggesting the presence of overdominant selection or the occurrence of outbreeding. Pairwise genetic distances indicated that the three indigenous camel breeds were genetically close to each other and genetically distant to the SN population. This genetic variability assessment by microsatellite analysis is important and useful for the conservation of local camel genetic resources as well as the future development of breeding programs.

Genetic diversity and population genetic structure of six dromedary camel (camelus dromedarius) populations in Saudi Arabia

Camels are an integral and essential component of the Saudi Arabian heritage. The genetic diversity and population genetic structure of dromedary camels are poorly documented in Saudi Arabia so this study was carried out to investigate the genetic diversity of both local and exotic camel breeds. The genetic diversity was evaluated within and among camel populations using 21 microsatellite loci. Hair and blood samples were collected from 296 unrelated animals representing 4 different local breeds, namely Majaheem (MG), Maghateer (MJ), Sofr (SO), and Shaul (SH), and two exotic breeds namely Sawahli (SL) and Somali (SU). Nineteen out of 21 microsatellite loci generated multi-locus fingerprints for the studied camel individuals, with an average of 13.3 alleles per locus. Based on the genetic analyses, the camels were divided into two groups: one contained the Saudi indigenous populations (MG, MJ, SH and SO) and the other contained the non-Saudi ones (SU and SL). There was very little gene flow occurring between the two groups. The African origin of SU and SL breeds may explain their close genetic relationship. It is anticipated that the genetic diversity assessment is important to preserve local camel genetic resources and develop future breeding programs to improve camel productivity.

Old World camels in a modern world - a balancing act between conservation and genetic improvement

Old World camels have served humans in cross‐continental caravans, transporting people and goods, connecting different cultures and providing milk, meat, wool and draught since their domestication around 3000–6000 years ago. In a world of modern transport and fast connectivity, these beasts of burden seem to be out‐dated. However, a growing demand for sustainable milk and meat production, especially in countries affected by climate change and increasing desertification, brings dromedaries (Camelus dromedarius) and Bactrian camels (Camelus bactrianus) back onstage and into the focus of animal breeders and scientists. In this review on the molecular genetics of these economically important species we give an overview about the evolutionary history, domestication and dispersal of Old World camels, whereas highlighting the need for conservation of wild two‐humped camels (Camelus ferus) as an evolutionarily unique and highly endangered species. We provide cutting‐edge information on the current molecular resources and on‐going sequencing projects. We cannot emphasise enough the importance of balancing the need for improving camel production traits with maintaining the genetic diversity in two domestic species with specific physiological adaptation to a desert environment.

Piebald Camels

Animal breeds are the diverse outcome of the thousands-year-long process of livestock domestication. Many of these breeds are piebald, resulting from the artificial selection by pastoralists of animals bearing a genetic condition known as leucism, and selected for their productive, behavioural, or aesthetical traits. Piebald dromedary camels have not been studied or discussed before, and their same existence is often overlooked. Based on fieldwork in Western Sahara, direct observations across Northern and East Africa and the Middle East, and a literature review, we address the morphological and behavioural traits, geographical distribution, taxonomy, and material and cultural importance of piebald (painted) camels. They are a hundreds-year-old camel breed used for caravans, as mounts, and for aesthetical and cultural reasons across Sudan, Niger, Mali, Mauritania, Western Sahara, and Morocco. While they are increasingly bred out of a pastoral context for tourism and entertainment in the Canary Islands, mainland Europe, and the USA, in part of their original African range, piebald camels are under threat due to wars, droughts, and demise of pastoral livelihoods. More research is needed about these 'beautiful and dignified' animals.

The history of Old World camelids in the light of molecular genetics

Old World camels have come into the focus as sustainable livestock species, unique in their morphological and physiological characteristics and capable of providing vital products even under extreme environmental conditions. The evolutionary history of dromedary and Bactrian camels traces back to the middle Eocene (around 40 million years ago, mya), when the ancestors of Camelus emerged on the North American continent. While the genetic status of the two domestic species has long been established, the wild two-humped camel has only recently been recognized as a separate species, Camelus ferus, based on molecular genetic data. The demographic history established from genome drafts of Old World camels shows the independent development of the three species over the last 100,000 years with severe bottlenecks occurring during the last glacial period and in the recent past. Ongoing studies involve the immune system, relevant production traits, and the global population structure and domestication of Old World camels. Based on the now available whole genome drafts, specific metabolic pathways have been described shedding new light on the camels' ability to adapt to desert environments. These new data will also be at the origin for genome-wide association studies to link economically relevant phenotypes to genotypes and to conserve the diverse genetic resources in Old World camelids.

The de novo genome assembly and annotation of a female domestic dromedary of North African origin

The single-humped dromedary (Camelus dromedarius) is the most numerous and widespread of domestic camel species and is a significant source of meat, milk, wool, transportation and sport for millions of people. Dromedaries are particularly well adapted to hot, desert conditions and harbour a variety of biological and physiological characteristics with evolutionary, economic and medical importance. To understand the genetic basis of these traits, an extensive resource of genomic variation is required. In this study, we assembled at 65× coverage, a 2.06 Gb draft genome of a female dromedary whose ancestry can be traced to an isolated population from the Canary Islands. We annotated 21,167 protein-coding genes and estimated ~33.7% of the genome to be repetitive. A comparison with the recently published draft genome of an Arabian dromedary resulted in 1.91 Gb of aligned sequence with a divergence of 0.095%. An evaluation of our genome with the reference revealed that our assembly contains more error-free bases (91.2%) and fewer scaffolding errors. We identified ~1.4 million single-nucleotide polymorphisms with a mean density of 0.71 × 10(-3) per base. An analysis of demographic history indicated that changes in effective population size corresponded with recent glacial epochs. Our de novo assembly provides a useful resource of genomic variation for future studies of the camel's adaptations to arid environments and economically important traits. Furthermore, these results suggest that draft genome assemblies constructed with only two differently sized sequencing libraries can be comparable to those sequenced using additional library sizes, highlighting that additional resources might be better placed in technologies alternative to short-read sequencing to physically anchor scaffolds to genome maps.