Search Results (8)

Taurine is essential for sustaining the body’s physiological equilibrium and is extensively utilized as a dietary supplement and immune system enhancer for aquatic creatures. The gut microbiota serves as a vital health indicator in animals. In this study, our goal was to evaluate the effects of dietary taurine on the gut microbiome of Chinese stripe-necked turtles (Mauremys sinensis). Turtles were evenly divided into three supplementation groups: a control group with no taurine in the diet, a low group with 0.1% taurine, and a high group with 0.4% taurine. High-throughput sequencing was employed to analyze the gut microbiome’s composition and structure. The results showed that the impact of taurine supplementation on the α-diversity and β-diversity of the gut microbiome was not statistically significant. At the phylum level, Firmicutes and Bacteroidetes predominated the gut microbiome. At the genus level, three beneficial bacteria, Clostridium_sensu_stricto_13, Pygmaiobacter, and Terrisporobacter showed significant differences under different levels of taurine supplementation and increased in abundance with the supplementation of taurine, while the harmful bacterium Brucella decreased in abundance with the addition of taurine and exhibited significant differences. Furthermore, LEfSe analysis and functional predictions highlighted significant variations in the functional traits of gram-positive intestinal bacteria among the different taurine supplementation levels. These findings imply that dietary taurine may alter the intestinal microbiome structure in Chinese stripe-necked turtles, offering valuable insights for the scientific assessment of taurine’s health benefits as a feed additive and potentially guiding the formulation of more informed and healthier feeding practices. Full article

The Chinese striped-necked turtle Mauremys sinensis, introduced into South Korea presumably in 2012, is considered an invasive alien species owing to its devastating impact, including hybridization with the native protected species Reeves’ turtle M. reevesii. Recently, the presence of M. sinensis has been confirmed throughout the country, and several sympatric areas with M. reevesii have been reported. Thus, field surveys were conducted at 47 sites across M. sinensis and M. reevesii habitats in South Korea to determine the extent of hybridization. Five sympatric sites were confirmed, and hybrid individuals were identified at four sites. Genetic analyses (COI and R35) of two individuals from Jeju Island confirmed maternal M. reevesii and paternal M. sinensis lineages. Hybridization presumably does not occur under natural conditions, and the hybrids likely originated from captive breeding. This study identifies for the first time the habitats of M. sinensis and its hybrids in the wild of South Korea. The management measures proposed in the current study could be of value for the conservation of the native species; however, our study did not include reproductive monitoring, and there is a need for such surveys as well as for systematic management of non-native turtles introduced into South Korea. Full article

Dietary lipids provide energy for animals and can also be converted into other nutrients (such as non-essential amino acids), which play a role in saving protein. The Chinese stripe-necked turtle is a protected and endangered species that has been bred in captivity; however, basic data on lipid requirements remain unavailable. In this study, 360 Mauremys sinensis (body weight of 65.32 ± 0.15 g) were randomly divided into six groups with three replicates per group; the turtles were fed experimental diets supplemented with various levels of fish oil (i.e., 1% (control group, CG), 3.5% (HF-1), 6% (HF-2), 8.5% (HF-3), 11% (HF-4), and 13.5% (HF-5)) for 10 weeks. The results showed that compared with CG, increasing the fish oil level promoted the growth performance of turtles, and the HF-3 group achieved the best effect. The HF-4 group showed the highest increases in the hepatosomatic index and viscerosomatic index. In addition, increased lipid levels also increased the crude lipid content and reduced the crude protein content in muscle tissue. Oil red O staining showed that the liver lipid content increased with the level of supplemented fish oil, which is consistent with the results of the hepatosomatic index. Compared with CG, triglyceride, total cholesterol, and low-density lipoprotein cholesterol increased significantly in both the liver and serum when fish oil levels exceeded 8.5% (p < 0.05), while high-density lipoprotein cholesterol decreased significantly. Aspartate transaminase and cerealthirdtransaminase levels in serum increased significantly when fish oil levels exceeded 8.5% (p < 0.05). Moreover, the activities of antioxidant enzymes (GSH-Px, SOD, T-AOC, and CAT) and MDA showed similar results, indicating that high fish oil levels (8.5–13.5%) caused liver tissue damage in M. sinensis. Increased fish oil levels significantly upregulated the expression levels of cytokines (IFN-γ, TNF-α, TGF-β1, IL-10, and IL-12) (p < 0.05), downregulated the expression levels of antioxidant enzyme-related genes (cat, mn-sod, and gsh-px), and increased apoptosis of liver cells. Supplementation of the diet with 3.5–6% fish oil improved the growth performance of M. sinensis, and the turtles maintained a beneficial immune status. The results provide a scientific basis for optimizing the commercial feed formula of M. sinensis. Full article

Butyl paraben (BuP) has been widely used as a preservative in the cosmetics, food, and medicine industries. Recently, it has become a new pollutant and has attracted much attention. In order to evaluate the toxic effect of BuP on aquatic animals, Chinese striped-neck turtles (Mauremys sinensis) were exposed to BuP solutions with different concentrations of 0, 5, 50, 500, and 5000 µg/L for 20 weeks. The results showed that with an increase in BuP concentration, the activity of antioxidant enzymes (SOD, CAT and GSH-PX) in liver decreased. The expression of key genes in the Nrf2-Keap1 signal pathways first increased and then decreased, while the expression of the HSP70 and HSP90 genes increased. In addition, the liver had an inflammatory reaction. The expression of the BAFF and IL-6 genes increased and then decreased with an increase in BuP concentration, while the expression of P50 and P65 increased significantly. Oxidative stress induced apoptosis, and the expression of pro-apoptosis genes (BAX, cytc, Caspase3 and Caspase9) increased, while the expression of the anti-apoptosis gene Bcl2 decreased. The results provide an important reference for the comprehensive ecological and health risk assessment of environmental BuP. Full article

Citizen science is emerging as a powerful tool for the early detection of biological invasions. The exotic pet trade has been deemed as the most significant cause of establishment for reptiles, and among them, turtles have the highest number of introduction events. In Europe, at least 13 species of alien freshwater turtles have been recorded in the wild. In Greece, only two species of alien turtles have been reported, namely the American pond slider Trachemys scripta and the Florida cooter Pseudemys floridana. In this study, we provide an updated checklist of the alien freshwater turtles recorded in Greece, using citizen science, personal observations, and literature. Our results provide the first records for the country of five species, namely the Florida red-bellied cooter Pseudemys nelsoni, the Eastern river cooter Pseudemys concinna, the Chinese stripe-necked turtle Mauremys sinensis, the Chinese soft-shelled turtle Pelodiscus sinensis, and the Common snapping turtle Chelydra serpentina and new localities for T. scripta. Similar to the myth of the Lernaean Hydra (i.e., for every head chopped off, more would regrow), the pet turtle trade has been proven to have multiple heads. Full article

According to the IUCN, Southeast Asia is the area of the world with the highest number of threatened turtle species. The current status of chelonians is particularly catastrophic in Vietnam. However, there is still a lack of field data to unambiguously support this fact for a few species. To better understand the freshwater turtle diversity and eventually undertake efficient conservation actions, we conducted surveys with local fishers using standardized questionnaires in two independent river systems in northern Vietnam. A total of 112 questionnaires were administered to as many fishers in April and October 2022. We directly observed four sympatric freshwater species (Pelodiscus sinensis, Palea steindachneri, Mauremys sinensis and Sacalia quadriocellata) in Lao Cai and Yen Bai provinces, and two species (Pelodiscus sinensis and Palea steindachneri) in Bac Giang, Hai Duong, Thai Binh, and Hung Yen provinces. Based on the interviews, we added as possible the presence of two other species (Rafetus swinhoei and Pelochelys cantorii) in each of the two study areas. Moreover, we recorded for the first time in Vietnam, two wild individuals of an invasive alien species, the Common snapping turtle (Chelydra serpentina), confirming that the distribution and ecology of turtle species in Vietnam is poorly understood. Furthermore, recent photos (year 2019) of a 38 kg softshell turtle, possibly attributable to Rafetus swinhoei, were recorded from a restaurant in the area. In conclusion, interviews with local fishers have been found to be useful for exploring the likely presence and the local distribution of the various turtle species. Full article

The unique topological structure of a turtle shell, including the special ribs–scapula relationship, is an evolutionarily novelty of amniotes. The carapacial ridge is a key embryonic tissue for inducing turtle carapace morphologenesis. However, the gene expression profiles and molecular regulatory mechanisms that occur during carapacial ridge development, including the regulation mechanism of rib axis arrest, the development mechanism of the carapacial ridge, and the differentiation between soft-shell turtles and hard-shell turtles, are not fully understood. In this study, we obtained genome-wide gene expression profiles during the carapacial ridge development of Mauremys reevesii using RNA-sequencing by using carapacial ridge tissues from stage 14, 15 and 16 turtle embryos. In addition, a differentially expressed genes (DEGs) analysis and a gene set enrichment analysis (GSEA) of three comparison groups were performed. Furthermore, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to analyze the pathway enrichment of the differentially expressed genes of the three comparative groups. The result displayed that the Wnt signaling pathway was substantially enriched in the CrTK14 vs. the CrTK15 comparison group, while the Hedgehog signaling pathway was significantly enriched in the CrTK15 vs. the CrTK16 group. Moreover, the regulatory network of the Wnt signaling pathway showed that Wnt signaling pathways might interact with Fgfs, Bmps, and Shh to form a regulatory network to regulate the carapacial ridge development. Next, WGCNA was used to cluster and analyze the expression genes during the carapacial ridge development of M. reevesii and P. sinensis. Further, a KEGG functional enrichment analysis of the carapacial ridge correlation gene modules was performed. Interesting, these results indicated that the Wnt signaling pathway and the MAPK signaling pathway were significantly enriched in the gene modules that were highly correlated with the stage 14 and stage 15 carapacial ridge samples of the two species. The Hedgehog signaling pathway was significantly enriched in the modules that were strongly correlated with the stage 16 carapacial ridge samples of M. reevesii, however, the PI3K-Akt signaling and the TGF-β signaling pathways were significantly enriched in the modules that were strongly correlated with the stage 16 carapacial ridge samples of P. sinensis. Furthermore, we found that those modules that were strongly correlated with the stage 14 carapacial ridge samples of M. reevesii and P. sinensis contained Wnts and Lef1. While the navajo white 3 module which was strongly correlated with the stage 16 carapacial ridge samples of M. reevesii contained Shh and Ptchs. The dark green module strongly correlated with the stage 16 carapacial ridge samples of P. sinensis which contained Col1a1, Col1a2, and Itga8. Consequently, this study systematically revealed the signaling pathways and genes that regulate the carapacial ridge development of M. reevesii and P. sinensis, which provides new insights for revealing the molecular mechanism that is underlying the turtle’s body structure. Full article

Globally, an increase in the transportation and expansion of the pet market is the most important cause of the invasion of non-native species. Invasion of non-native species disturbs native ecosystems and leads to socio-economic problems. The pet trade involving turtles has been globally recognized as the route through which non-native species enter ecosystems. As a result, the invasion of non-native turtles worldwide is causing problems such as competition, predation, transmission of parasites, and hybridization with native turtles. Every year, both the number of non-native turtles imported as pets in the Republic of Korea and the number of introduced species found in the wild is increasing. However, the current status of non-native turtles in the wild is not well known, posing major challenges to their management. In this study, we aimed to determine the current status of non-native turtles introduced into the wild in Korea. We analyzed the factors associated with the detection and distribution of non-native turtles. In total, 1587 of non-native turtles (three families, six genera, and 13 species including subspecies) were found in 648 sites in Korea: Chelydra serpentina, Mauremys sinensis, Chrysemys picta bellii, Graptemys ouachitensis, G. pseudogeographica pseudogeographica, G. p. kohni, Pseudemys concinna, P. nelsoni, P. peninsularis, P. rubriventris, Trachemys scripta elegans, T. s. scripta, and T. s. troostii. There was relationship between the distribution of non-native turtles and environmental factors such as precipitation and temperature. Moreover, human factors such as number of human populations and size of region were significantly related with the distribution and number of non-native turtles. In conclusion, it is likely that human factors are associated with the influx of invasive turtles to the natural habitat, while the possibility of survival and adaption for the turtles is associated mainly with environmental factors. Our result will be an essential guideline not only for understanding the current status of non-native turtles in Korea, but also for establishing strategies for management and control. Full article