Captivity Influences Gut Microbiota in Crocodile Lizards (Shinisaurus crocodilurus)

Abstract

Captivity is an important measure for conservation of an endangered species, and it is becoming a hot topic in conservation biology, which integrates gut microbiota and endangered species management in captivity. As an ancient reptile, the crocodile lizard (Shinisaurus crocodilurus) is facing extreme danger of extinction, resulting in great significance to species conservation in the reserve. Thus, it is critical to understand the differences in gut microbiota composition between captive and wild populations, as it could provide fundamental information for conservative management of crocodile lizards. Here, fecal samples of crocodile lizards were collected from two wild and one captive populations with different ages (i.e., juveniles and adults) and were analyzed for microbiota composition by 16S ribosomal RNA (rRNA) gene amplicon sequencing. This study showed that the lizard gut microbiota was mainly composed of Firmicutes and Proteobacteria. The gut microbiota composition of crocodile lizard did not differ between juveniles and adults, as well as between two wild populations. Interestingly, captivity increased community richness and influenced community structures of gut microbiota in crocodile lizards, compared with wild congeners. This was indicated by higher abundances of the genera Epulopiscium and Glutamicibacter. These increases might be induced by complex integration of simple food resources or human contact in captivity. The gut microbiota functions of crocodile lizards are primarily enriched in metabolism, environmental information processing, genetic information processing, and cellular processes based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. This study provides fundamental information about the gut microbiota of crocodile lizards in wild and captive populations. In the future, exploring the relationship among diet, gut microbiota, and host health is necessary for providing animal conservation strategies.

The invasive red-eared slider turtle is more successful than the native Chinese three-keeled pond turtle: evidence from the gut microbiota

“…Our data showed that in both species the most functionally distinct categories were focused on metabolism, genetic information processing and environmental information processing at the first function level, followed by gene functions associated with membrane transport, replication and repair, amino acid metabolism and carbohydrate metabolism at the second level, and transporters and ABC transporters at the third level. In reptiles, that the gene functions of the gut microbes are associated with metabolism has been reported for the timber rattlesnake Crotalus horridus ( Mclaughlin, Cochran & Dowd, 2015 ), the crocodile lizard Shinisaurus crocodilurus ( Tang et al, 2020 ), and the northern grass lizard Takydromus septentrionalis ( Zhou et al, 2020 ). Similar results have also been reported for birds ( Wang et al, 2018 ) and mammals ( Zhao et al, 2018 ).…”

“…For example, early growth, household location, and antibiotic experiences during pregnancy are correlated with the early gut microbial composition in humans ( Vatanen et al, 2019 ). Seasonal variation in diets may lead to changes in the gut microbiota ( Kartzinel et al, 2019 ), and exposure of host animals to artificial environments (e.g., animals in captivity) may lead to an increase in the abundance of human disease-related functional genes in the gut microbes ( Tang et al, 2020 ; Zhou et al, 2020 ). Taken together, the gut microbial community is affected by the host’s genetic background, diets and individual status and, in turn, affects the physiological, behavioral and even evolutionary processes of the host.…”

Environment-Dependent Variation in Gut Microbiota of an Oviparous Lizard (Calotes versicolor)

“…The lizrads’ gut microbial community compositions and structures were similar to those observed in mammals, and previous studies have documented general patterns. Further, gut bacterial diversity did not depend on the diversification of lizard hosts [ 33 ], but it varied along altitudes, diet and captive environment [ 2 , 14 , 34 , 35 , 36 , 37 , 38 ], and changed due to climate warming [ 32 ]. There was no significant difference in gut bacterial diversity between juveniles and adults [ 35 ], but males had significantly higher gut bacterial diversity and richness than do females [ 39 ], while non-gestation females had higher gut bacterial richness than do late-gravid females [ 11 ].…”

“…The microbiome composition differs between the large intestine and small intestine in Agkistrodon piscivorus [ 42 ]. However, the differences in the relative abundance in Shinisaurus crocodilurus were reported, such as Bacteroidetes (32.1%) and Proteobacteria (47.9%) were the dominant phyla in the cloacal swab samples [ 38 ], whereas Firmicutes (61.2%) and Proteobacteria (35.8%) were the dominant phyla in fecal samples [ 35 ]. The majority of these studies have been conducted using fecal samples, cloaca swabs, or the intestinal contents collected from wild-caught or captive individuals.…”

Parasites, Drugs and Captivity: Blastocystis-Microbiome Associations in Captive Water Voles

“…A common objective of animal studies has been to explore the extent of bacterial community perturbations in the gut caused by anthropogenic intervention and investigate resulting ramifications on animal fitness and longevity [ 13 , 14 , 15 , 16 , 17 , 18 ]. Recent investigations have focused on comparing gut microbiota of captive animals and their wild counterparts in order to assess links to the captive lifestyle [ 14 , 19 , 20 , 21 ]. Roles of microbiota on host survival upon release have also been examined.…”