Anthony, N. B. | bioRxiv Science

bioRxiv2023

Evaluating the ileal and cecal microbiota composition of a 1940 heritage genetic line and a 2016 commercial line of white leghorns fed representative diets from 1940 and 2016

This study was conducted to identify and evaluate the differences between the microbiome composition of the ileum and ceca of 1940 and 2016 genetic strains of white leghorns fed representative contemporary diets from those times. Ileal and cecal samples were aseptically collected from both genetic lines at 69 weeks of age. The genomic DNA of the ileal and cecal contents were extracted and the V4 region of the 16S rDNA was sequenced on an Illumina Miseq. Microbiota data were filtered and aligned using the QIIME2 2020.2 pipeline. Alpha and beta diversity metrics were generated and the Analysis of Composition of Microbiomes (ANCOM) was utilized to determine significantly different taxa. Data were considered significant at P [≤] 0.05 for main effects and Q [≤] 0.05 for pairwise differences. Alpha diversity of the ileum and ceca were significantly different (P = 0.001; Q = 0.001; however, no differences between genetic lineage were observed (P > 0.05; Q > 0.05). The beta diversity between the ileum and ceca, as well as between the genetic lines (1940 vs. 2016) were significantly different from one another (P = 0.001; Q = 0.001). Using ANCOM, Proteobacteria and Actinobacteriota were significantly different than other phyla (P 0.05) with a higher relative abundance of Proteobacteria being observed among treatment groups 2 and 3, while Actinobacteriota had higher relative abundance in treatment groups 1 and 4. Among the significantly different genera in the ileum, Pseudomonas, Rhizobiaceae, Leuconostoc, and Aeriscardovia were different (P 0.05) with treatment groups 1 and 4 having a higher relative abundance of Aeriscardovia, while treatment groups 2 and 3 had higher relative abundance in both Pseudomonas and Leuconostoc. In the ceca, Proteobacteria, Firmicutes, Actinobacteriota, and Euryarchaeota were significantly different phyla (P 0.05) with Firmicutes having the highest relative abundance across all treatment groups. Among the significantly different genera (Pseudomonas, Leuconostoc, Alloprevotella, and Aeriscardovia), Alloprevotella had the highest relative abundance across all treatment groups 1 and 2, while Leuconostoc and Pseudomonas had the highest relative abundance in treatment group 4. Results from this study suggest that genetic makeup in conjunction with the nutritional composition of laying hens influences the cecal and ileal microbiota of corresponding hens.

microbiology↗

bioRxiv2018

Further Investigation of Mitochondrial Biogenesis and Gene Expression of Key Regulators in Ascites- Susceptible and Ascites-Resistant Broiler Research Lines

We have extended our previous survey of the association of mitochondrial prevalence in particular tissues with ascites susceptibility in broilers. We previously reported that in breast muscle of 22 week old susceptible line male birds had significantly higher mtDNA copy number relative to nuclear copy number (mtDNA/nucDNA), compared to resistant line male birds. The higher copy number correlated with higher expression of PPARGC1A mRNA gene. Ascites is a significant metabolic disease associated with fast-growing meat-type chickens (broilers) and is a terminal result of pulmonary hypertension syndrome. We now report the mtDNA/nucDNA ratio in lung, liver, heart, thigh, and breast of both genders at 3, and 20 weeks old. At 3 weeks the mtDNA/nucDNA ratio is significantly higher in lung, breast, and thigh for susceptible line males compared to the resistant line males. Conversely, we see the opposite for lung and breast in females. At 20 weeks of age the differences between males from the two lines is lost for lung, and thigh. Although there is a significant reduction in the mtDNA/nucDNA ratio of breast from 3 weeks to 20 weeks in the susceptible line males, the susceptible males remain higher than resistant line males for this specific tissue. We assessed relative expression of five genes known to regulate mitochondrial biogenesis for lung, thigh and breast muscle from males and females of both lines with no consistent pattern to explain the marked gender and line differences for these tissues. Our results indicate clear sex differences in mitochondrial biogenesis establishing a strong association between the mtDNA quantity in a tissue-specific manner and correlated with ascites-phenotype. We propose that mtDNA/nucDNA levels could serve as a potential predictive marker in breeding programs to reduce ascites.

developmental biology↗