Investigation on the characteristics of gut microbiota in critically endangered blue-crowned laughingthrush (Garrulax courtoisi).

Blue-crowned laughingthrush (Garrulax courtoisi), passeriformes, is a critically endangered bird endemic to China. Gut microbiota is well known to play a pivotal role in host health and survival. Thus, the understanding of the microbial communities associated with Garrulax courtoisi could be beneficial to save this species from the brink of extinction. In this study, we used 16 s rDNA amplicon sequencing to investigate the gut community composition and microbial diversity of the Garrulax courtoisi population reared in Nanchang Zoo. The results showed that there were 31 phyla that were dominated by Firmicutes, Proteobacteria, Bacteroidetes, and Cyanobacteria in the intestine of Garrulax courtoisi. Compared with previous studies on birds, the Cyanobacteria exhibited an excessive abundance, which may be largely related to the personal lifestyle of Garrulax courtoisi. At the genus level, a total of 552 genera were identified, among which, 21 key genera constituted the core microbiome, including some culturable bacterial genera such as Lactobacillus, Acinetobacter, and Deinococcus. In the meanwhile, we found that there were remarkable intraspecific differences both in terms of microbial community structures, representative biomarkers and predicted functions between the parental generation and their offspring of the population investigated in this study. Furthermore, we also summarized their different eating behaviors and predicted its association with gut microbiota. This study provided the needed pieces of information about these extremely rare birds, Garrulax courtoisi, whose community composition and microbial diversity are hardly known. Importantly, these findings could contribute to our knowledge of the gut health of Garrulax courtoisi and advance the comprehensive conservation of this endangered bird.

Clinical and Pathological Aspects of Systemic Isospora Infection in Blue-crowned Laughing Thrushes (Garrulax courtoisi) at Jersey Zoo.

Based on a review of species mortalities, systemic Isospora species was identified as the primary cause of death in 22% (19 of 87) of blue-crowned laughing thrushes (BCLTs; Garrulax courtoisi) at the Jersey Zoo between 1997 and 2016. Fifty-eight percent of the affected birds were between 1 and 2 years old, and in 89% of cases, death occurred between August and December. Abnormal clinical findings in BCLTs with Isospora species infections included hepatomegaly and pectoral muscle myositis in 79% of the cases. The results of diagnostic blood testing in 90% of infected BCLTs 30 days before death were consistent with a severe leukocytosis with greater than 20% of mononuclear cells infected by merozoites. The most common lesions identified during gross necropsy examination were splenomegaly (100%), hepatomegaly (95%), and multifocal, raised, white foci in pectoral (84%) and heart (79%) muscle. Lymphohistiocytic inflammation was identified in the liver, heart, spleen, lung, striated muscle, and kidney tissue of birds with positive results for Isospora species. Merozoites were often observed in spleen, liver, pectoral muscle, and hearts of infected BCLTs. Polymerase chain reaction diagnostic testing that targeted the cytochrome c oxidase subunit, followed by Sanger sequencing, was used to confirm Isospora species in all 14 birds tested. Of samples tested, the highest genetic correlation was with GenBank accession number KT203397 (Isospora species JRB-2016 mitochondrion).

Home range size and habitat use of the blue-crowned laughingthrush during the breeding season.

The home range size and habitat use of the blue-crowned laughingthrush (Garrulax courtoisi, hereafter BCLT), a critically endangered, subtropical, cooperative-breeding bird species in southeast China, were studied during its breeding period using radio telemetry at different sites during 3 consecutive years (2016-18, from May to June of each year). A total of 17 birds (12 males, four females, and one of unknown sex) were tagged, and a total 1515 locations (mean ± se = 89.12 ± 11.42) were obtained over 54 days of tracking. The average 100% minimum convex polygon (MCP) home range size was 10.05 ± 1.17 ha, and the estimated KDE core area (fiexed kernel density estimator, KDE) size was 7.84 ± 1.18 ha. According to the Wilcoxon rank sum tests, both the 100% MCP and KDE core area size of males did not significantly differ from those of females. There were no significant differences in the 100% MCP or KDE core area sizes of the three breeding sites. The available habitats in the breeding sites included water areas, shrubs, grass plots, woodland, residential areas, vegetable field, farmland, and sandy beaches; among them, only woodland was significantly preferred by BCLTs. Woodland (average use ratio was 45.86 ± 1.74%) was strongly preferred by BCLTs for nesting, foraging and roosting. Shrubs/grass plots (24.72 ± 3.39%) and vegetable plots (11.80 ± 1.83%) were used relatively more often than the other habitats, except woodland, since shrubs were always used as perches, and vegetable plots were rich in food resources. Vertically, the canopy layer was used most often from April to June, but it was used most in May when the birds were hatching and brooding. This result indicates that BCLT is predominantly active in the upper strata during the breeding season. In addition, broadleaved trees within or adjacent to villages were important activity areas for the breeding birds; protection and management measures should be increased in these areas.