Succession of the turkey gastrointestinal bacterial microbiome related to weight gain

Abstract

Because of concerns related to the use of antibiotics in animal agriculture, antibiotic-free alternatives are greatly needed to prevent disease and promote animal growth. One of the current challenges facing commercial turkey production in Minnesota is difficulty obtaining flock average weights typical of the industry standard, and this condition has been coined “Light Turkey Syndrome” or LTS. This condition has been identified in Minnesota turkey flocks for at least five years, and it has been observed that average flock body weights never approach their genetic potential. However, a single causative agent responsible for these weight reductions has not been identified despite numerous efforts to do so. The purpose of this study was to identify the bacterial community composition within the small intestines of heavy and light turkey flocks using 16S rRNA sequencing, and to identify possible correlations between microbiome and average flock weight. This study also sought to define the temporal succession of bacteria occurring in the turkey ileum. Based upon 2.7 million sequences across nine different turkey flocks, dominant operational taxonomic units (OTUs) were identified and compared between the flocks studied. OTUs that were associated with heavier weight flocks included those with similarity to Candidatus division Arthromitus and Clostridium bartlettii, while these flocks had decreased counts of several Lactobacillus species compared to lighter weight flocks. The core bacterial microbiome succession in commercial turkeys was also defined. Several defining markers of microbiome succession were identified, including the presence or abundance of Candidatus division Arthromitus, Lactobacillus aviarius, Lactobacillus ingluviei, Lactobacillus salivarius, and Clostridium bartlettii. Overall, the succession of the ileum bacterial microbiome in commercial turkeys proceeds in a predictable manner. Efforts to prevent disease and promote growth in the absence of antibiotics could involve target dominant bacteria identified in the turkey ileum that are associated with increased weight gain.

Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives

“…These "pioneering species" pave the way for colonization of the gut by obligate anaerobes by consuming oxygen, producing carbon dioxide, and changing the pH (10). During early stages of succession, bacterial diversity is often low, and the community changes rapidly; this result has been observed in the mammalian digestive tract and also in the insect gut and in other, non-host-associated environments (9)(10)(11)(12)(13)(14)(15)(16)(17). However, after this period of early succession, the bacterial community reaches a steady state often referred to as the "climax community."…”

“…The event often coincides with a later developmental stage of the organism harboring the bacterial community (9,11,12,15). Bacterial diversity and the total number of bacteria are higher in a climax community than during early succession (9,10,17). The honey bee is a holometabolous insect and moves through a life cycle marked by the metamorphic transition from larval stage into a developed imago form.…”

“…The climax community of a bacterial population would be reached when there is an equilibrium that can be maintained of a specific mix of bacteria (9,10). The event often coincides with a later developmental stage of the organism harboring the bacterial community (9,11,12,15). Bacterial diversity and the total number of bacteria are higher in a climax community than during early succession (9,10,17).…”

“…From studies of bacterial succession in the digestive tract of mammals, we know that young are relatively uncolonized and that the first members to colonize the gut are often facultative anaerobes, such as Escherichia coli (9)(10)(11)(12). These "pioneering species" pave the way for colonization of the gut by obligate anaerobes by consuming oxygen, producing carbon dioxide, and changing the pH (10).…”

“…However, after this period of early succession, the bacterial community reaches a steady state often referred to as the "climax community." The climax community of a bacterial population would be reached when there is an equilibrium that can be maintained of a specific mix of bacteria (9,10). The event often coincides with a later developmental stage of the organism harboring the bacterial community (9,11,12,15).…”