Effect of Long-term Relative High and Low Environmental Temperatures on the Microbial Diversity of Ileum in Broilers

PurposeTo explore the effects of long-term relative high and low environmental temperature on the ileum microbial diversity in broilers.

MethodThree hundred one-day-old Avian broilers were randomly divided into three groups: high temperature group (36.5 ℃, HI), control group (33.5 ℃, CI) and low temperature group (30.5 ℃, LI). The temperature was decreased as a parallel, and the temperature difference among each group was 3 ℃. Other feeding conditions were the same, and 12 broilers in each group were slaughtered at 22 ℃, 19 ℃ and 16 ℃ on the 42th day. Ileum chyme was collected to 16S rRNA gene sequencing analysis.

Result(1) Compared with CI group, Shannon and Simpson index in HI and LI groups were significantly higher (P<0.05). (2) At the phylum level, the abundance of Firmicutes, Cyanobacteria/Chloroplast and the ratio of Firmicutes to Bacteroides (F/B) in the ileum of the HI group were significantly higher than those of the CI group, while the abundance of Bacteroides was significantly lower than that of the CI group (P<0.05); At the genus level, the abundance of Lactobacillus and Turicibacter in ileumin HI group was significantly higher than that in CI group, while the abundance of Clostridium XI and Escherichia/Shigella in ileum in LI group was significantly lower than that in CI group (P<0.05). (3) Transcription machinery signal transduction pathway was significantly enriched in CI group. Eighteen signal pathways such as DNA repair and recombination proteins were significantly enriched in HI group. Fourteen signal pathways such as glyoxylate and dicarboxylate metabolism were significantly enriched in LI group. (4) There was a positive correlation between Clostridium XVIII and transcription machinery pathway in CI group, Lactobacillus and phosphotransferase system pathway in HI group, and Pandoraea and glyoxylate and dicarboxylate metabolism pathway in LI group.

ConclusionThe results showed that the ileum microbial diversity of broilers increased in long-term relatively low temperature environment, while the ratio of F/B, Clostridium XI and Escherichia/Shigella decreased in long-term relatively low temperature environment, while in long-term relatively high temperature environment, the ileum microbial diversity increased, the ratio of F/B decreased, and the abundance of Lactobacillus and Turicibacter increased, which provided a theoretical basis for healthy breeding of broilers.