Flaxseed promotes productive performance through regulating gut microbiome in ducks

Flaxseed has been widely used in animal diets to increase the omega-3 polyunsaturated fatty acid content in animal products and promote overall animal health, but little known about its effects on the productive performance and the mictobita of gut of laying duck. Jinding duck, a Chinese indigenous breed, was used in the study. The corn-soybean basal diet supplemented with 0, 2%, 3% 4% and 5% flaxseed were provided to Control, 2% Fla, 3% Fla, 4% Fla and 5% Fla groups for 53 days, respectively. Compared with Control group, groups fed with flaxseed diets showed higher egg production, egg mass, ovary weight and more preovulatory follicles. The Docosahexaenoic Acid content of egg was extremely significantly elevated by flaxseed diets (P < 0.01), and the albumen height and haugh unit were elevated, especially in 4% Fla and/or 5% Fla group (P < 0.05). Groups 4% Fla and 5% Fla had highest ileal villus height, jejunal and ileal crypt depth. Moreover, Flaxseed diets significantly increased the levels of IgG and IgM in all Fla groups (P < 0.01), while increased IgA levels except for in 3% Fla group (P < 0.05). The results of 16s rDNA sequencing showed that flaxseed diet altered the microbial composition of gut and reduced the diversity and evenness of gut microbial communities except for 5% Fla. The correlation analysis identified Blautia, Butyricicoccus and Subdoligranulum positively associated with egg production. Genera Fourinierella, Fusobacterium and Intestinimonas positively associated with ovary weight, haught unit and album height. And Mucispirillum positively associated with haugh unit and album height. This study has suggested that flaxseed play a positive role in productive performance, the overall or intestinal health of laying ducks.