Comparison of Cecal Microbiota and Performance Indices Between Lean-Type and Fatty-Type Pekin Ducks

Abstract

Fatty-type (FT) Pekin ducks exhibit higher lipid deposition than lean-type (LT) ducks. The gut microbiota plays an important role in modulating fat metabolism. We compared the growth performance, slaughter performance, and cecal microbiota of FT and LT Pekin ducks and analyzed the role of cecal microbiota in lipid deposition in Pekin ducks. A total of 140 1-day-old FT and LT Pekin ducks with similar body weights were randomly assigned to 10 cages, with 14 ducks in each replicate. All ducks were fed commercial diets from 28 to 42 days of age. Results showed that the average body weight and feed intake of FT ducks were higher than those of LT ducks. The breast muscle and eviscerated percentages of LT ducks were higher than those of FT ducks; the abdominal fat and sebum percentages of LT ducks were lower than those of FT ducks at 6 weeks of age (P < 0.01). 16S DNA sequencing of the cecal microbiota revealed that the bacterial abundance differed between FT and LT ducks at 4 and 6 weeks of age. The abundance of Firmicutes was higher, while that of Fusobacteria and Fusobacterium was lower in LT ducks than in FT ducks at 4 weeks of age. The abundance of Spirochaetes was higher, while that of Firmicutes and Bacteroides was lower in LT ducks than in FT ducks at 6 weeks of age. The abundance of Spirochaetes and Brachyspira in LT ducks was higher at 6 weeks than at 4 weeks of age. Interestingly, the abundance of Firmicutes and Bacteroides in FT ducks was higher at 6 weeks of age than at 4 weeks of age, while that of Fusobacteria and Fusobacterium was lower at 6 weeks than at 4 weeks of age. Linear discriminant analysis effect size analysis showed that Spirochaetes, Brachyspira, Alistipes, Campylobacter, Megamonas, Butyricicoccus, and Fusobacteria may be involved in the fat metabolism pathway as specific markers. We reveal the differences in microbial abundance in the cecal microbiota between FT and LT Pekin ducks and provide an insight into the role of cecal microbiota in lipid deposition in Pekin ducks.

Keywords: Pekin duck; cecal microbiota; fat deposition; fatty-type; growth performance; lean-type; plasma biochemical index; slaughter percentage.

FIGURE 1

Effects of different age and strain on cecal microbial OUT. Venn diagrams for microbial OTU compositions. Control group: L.WK4, Four-week-old lean-type Pekin duck; F.WK4, Four-week-old fatty-type Pekin duck; L.WK6, Six-week-old lean-type Pekin duck; F.WK6, Six-week-old fatty-type Pekin duck.

FIGURE 2

Effects of different age and strain on the diversities in the cecal microbial. (A) Shannon index. (B) Simpson index. (C) Chao1 index. (D) ACE index. (E) The principal component analysis. PCA plot about the cecal microbiota. (F) PLS-DA sample plot with confidence ellipse plots. Control group: L.WK4, Four-week-old lean-type Pekin duck; F.WK4, Four-week-old fatty-type Pekin duck; L.WK6, Six-week-old lean-type Pekin duck; F.WK6, Six-week-old fatty-type Pekin duck (data are mean ± SD).

FIGURE 3

(A) Box plot of inter-group and intra-group beta distance (ANOSIM analysis) of L.WK4 and L.WK6. (B) Box plot of inter-group and intra-group beta distance (ANOSIM analysis) of F.WK4 and L.WK4. (C) Box plot of Inter-group and Intra-group Beta distance (ANOSIM analysis) of F.WK4 and F.WK6. (D) Box plot of inter-group and intra-group beta distance (ANOSIM analysis) of F.WK6 and L.WK6. L.WK4, four-week-old lean-type Pekin duck; F.WK4, four-week-old fatty-type Pekin duck; L.WK6, six-week-old lean-type Pekin duck; F.WK6, six-week-old fatty-type Pekin duck.

FIGURE 4

Comparison of cecal microbial community structure between lean-type and fatty-type Pekin duck. (A) The beta-diversity index (weighted UniFrac distance) was not significant among the 4 groups (P > 0.05). The box shows the quartiles above and below the median, with a dark line at the center of the box denoting the median and black dots outside the box showing the outlier. (B) The UPGMA Cluster Tree displaying the relative abundance of predominant bacteria at the phylum level in each group (weighted UniFrac distance). L.WK4, Four-week-old lean-type Pekin duck; F.WK4, Four-week-old fatty-type Pekin duck; L.WK6, Six-week-old lean-type Pekin duck; F.WK6, Six-week-old fatty-type Pekin duck.

FIGURE 5

The top 10 relative abundance of microbiota community (level phylum and level genera) indicate by histogram. (A) The top 10 phylum with the highest abundance. (B) The top 10 genera with the highest abundance. L.WK4, Four-week-old lean-type Pekin duck; F.WK4, Four-week-old fatty-type Pekin duck; L.WK6, Six-week-old lean-type Pekin duck; F.WK6, Six-week-old fatty-type Pekin duck.

FIGURE 6

Phylum and genus level OTU analysis taxa heatmap cluster group. (A) Heatmap of the top 20 most abundant phyla. (B) The top 35 most abundance genera in microbial samples in each group. (C) Heatmap of the top 20 most abundant phyla. (D) The top 35 most abundance genera in two kinds of strains of microbial samples. The phylum and genera with higher abundance are shown in red, whereas those with lower abundance are shown in blue. L.WK4, Four-week-old lean -type Pekin duck; F.WK4, Four-week-old fatty-type Pekin duck; L.WK6, Six-week-old lean-type Pekin duck; F.WK6, Six-week-old fatty-type Pekin duck.

FIGURE 7

Biomarkers of discriminative bacteria (from phylum to genus) in different temperature groups identified by LEfSe analysis (LDA score ≥ 4). The length of the bar chart represents the influence size of the different species (i.e., LDA score). L.WK4, Four-week-old lean-type Pekin duck; F.WK4, Four-week-old fatty-type Pekin duck; L.WK6, Six-week-old lean-type Pekin duck; F.WK6, Six-week-old fatty-type Pekin duck.

FIGURE 8

Function Prediction. (A) Tax4Fun features annotated clustering heat maps. According to the functional annotations and abundance information of the samples in the database, the top 35 functions and their abundance information in each sample were selected to draw a heat map, and the clustering was conducted from the level of functional differences. (B) KEGG pathway annotation. Statistical map of genetic prediction results.

FIGURE 9

Correlation between performances indices and gut microbiota diversity. (A) Correlation Circle plot representing each type of selected features for the Peking duck. The correlation between two variables is positive if the angle is sharp, negative if the angle is obtuse, and null if the vectors are perpendicular. The longer the distance to the origin, the stronger the relationship between the variables. For the sake of interpretability, variables are not represented as vectors but as the end points of the vectors in MixOmics. Two circles are usually represented, of radii 0.5 and 1, to better visualize the “important” variables. (B) Clustered Image Map (Euclidean Distance, Complete linkage). Samples are represented in rows, selected features on the first component in columns.