Gut Microbiome Differences in Rescued Common Kestrels (Falco tinnunculus) Before and After Captivity

Abstract

Gut microbes significantly impact animal health, yet research on the gut microbiota of most birds, especially raptors, is lacking. This study investigated the effects of dietary and environmental changes on the composition and abundance of gut microbiota in 17 rescued common kestrels (Falco tinnunculus) through 16S rRNA gene high-throughput sequencing of microorganisms in the feces of the birds. Firmicutes (relative abundance, 43.63%), Proteobacteria (37.26%), Actinobacteria (7.31%), and Bacteroidetes (5.48%) were the dominant phyla in the gut microbiota of the common kestrels. A comparison of the gut microbiota before and after captivity revealed that community composition and abundance of the common kestrel gut microbiota differed among different living conditions including diet and environment. At the phylum level, the abundance of Firmicutes was higher (P < 0.05), and that of Proteobacteria was lower (P < 0.05), after captivity (54.62 and 27.16%, respectively) compared with before captivity (33.67 and 46.41%, respectively), but no significant differences were found among other phyla. At the genus level, the abundance of Lactobacillus was higher (P < 0.05) after captivity (15.77%) compared with the abundance before captivity (5.02%). Hierarchical clustering and principal component analyses showed that common kestrels in different living conditions exhibited differences (P < 0.05) in gut microbiota at phylum and genus levels. Functional prediction of gene sequences using PICRUSt2 further revealed that pathways related to glucose metabolism and amino acid metabolism were enhanced (P < 0.05) after captivity. Collectively, the findings from this study demonstrated that the relative abundance of specific microbes in the gut of the rescued common kestrels either increased or decreased, and that dietary and environment changes might be the predominant factors affecting the gut microbiota of these birds during rescue or captivity.

Comparison of gut microbiota between immigrant and native populations of the Silver-eared Mesia (Leiothrix argentauris) living in mining area

“…Some studies of other wild birds have found Firmicutes to be the dominant species in the gut microbiota (Wang et al, 2017;Oliveira et al, 2020;Wu et al, 2021). In several other studies on wild birds, nevertheless, Proteobacteria were found to have a higher abundance than Firmicutes (Zhou et al, 2020;Zhang et al, 2022). Even so, compared with our study in which Proteobacteria accounted for almost 90% of the intestinal flora, Proteobacteria in their study were only slightly higher than Firmicutes.…”

“…We also predicted the metabolic function of the gut microbiota of the Silver-eared Mesia. The metabolic pathways predicted by PICRUSt2 were consistent with those predicted by other wild species ( Figure 6A ; Zhou et al, 2020 ; Jiang F. et al, 2021 ; Zhang et al, 2022 ). Microbial metabolic pathways (such as xenobiotics biodegradation metabolism, carbohydrate metabolism, amino acid metabolism, and metabolism of cofactors and vitamins) accounted for more than 60% of the 31 predicted most abundant pathways.…”

“…This is the first study to show the gut microbiota of Silver-eared Mesia whose habitat has been altered by trade. Previous studies have focused on comparing native habitats with captivity ( Wienemann et al, 2011 ; Sun et al, 2019 ; Oliveira et al, 2020 ; San Juan et al, 2021 ; Grieves et al, 2022 ; Zhang et al, 2022 ). However, under captive conditions, the host’s living environment and diet are artificially controlled, so it is difficult to reflect the impact of the real field environment on the intestinal microbiota of immigrant species.…”

Falcon gut microbiome is shaped by diet and enriched inSalmonella

“…However, microbiome studies investigating their gut microbiomes are scarce. As a result, whether genetics, evolutionary histories, and diet have a measurable effect on the raptor gut microbiomes has remained unclear (18-21). We sequenced purebred and hybrid falcons of multiple species in this study and found that the gut microbiome composition of the falcons did not differ between sex, age, or purebred status, indicating that genetic variations in the falcon genome may have minor contributions in shaping their gut microbiota.…”

“…However, bird microbiome studies have predominantly focused on birds of commercial importance (17). Uber-carnivorous raptors whose diet almost exclusively consists of animal flesh, are highly underrepresented in the microbiome literature (18), with the exception of a few studies that include a handful of hawks, eagles, vultures, and falcons (15,(18)(19)(20)(21).…”