Cecal microbiome composition and metabolic function in probiotic treated broilers.

Probiotics have become increasingly popular in the poultry industry as a promising nutritional intervention to promote the modulation of intestinal microbial communities and their metabolic activities as a means of improving health and performance. This study aimed to determine the influence of different probiotic formulations on the taxonomic and metabolic profiling of cecal microbial communities, as well as to define associations between cecal microbiota and growth parameters in 21 and 42-day-old broilers. Probiotics investigated included a synbiotic (SYNBIO), a yeast-based probiotic (YEAST), and three single-strain formulations of spore-forming Bacillus amyloliquefaciens (SINGLE1), B. subtilis (SINGLE2) and B. licheniformis (SINGLE3). Dietary inclusion of SYNBIO, YEAST, SINGLE2, and SINGLE3 into the diets supported a significant stimulation of BW and BWG by 7 days of age. Besides, SYNBIO reduced the overall mortality rate by 42d (p<0.05). No significant variation was observed among different probiotic-based formulations for cecal microbiota composition. However, there was a treatment-specific effect on the metabolic profiles, with a particular beneficial metabolic adaptation by the microbiota when supplemented by SYNBIO and SINGLE2. Furthermore, the population of Lactobacillales was identified to be strongly associated with lower Enterobacteriales colonization, higher BW means, and lower mortality rate of growing broilers. Overall, the results emphasize that probiotic supplementation may enhance the microbial energy metabolism in the ceca of young broilers.

Comparative effectiveness of probiotic-based formulations on cecal microbiota modulation in broilers.

The potential of probiotics to manipulate the intestinal microbial ecosystem toward commensal bacteria growth offers great opportunity for enhancing health and performance in poultry. This study aimed to evaluate the efficacy of five probiotic-based formulations in modulating cecal microbiota in broilers at 21 and 42 days of age. Probiotics investigated included a synbiotic (SYNBIO), a yeast (YEAST), and three single-strain formulations of Bacillus amyloliquefaciens (SINGLE1), B. subtilis (SINGLE2) and B. licheniformis (SINGLE3). Alpha-diversity analyses showed that cecal microbiota of SINGLE1, SINGLE2, and YEAST had low diversity compared to the control diet with no feed additive (CON) at 21d. At the same age, weighted Unifrac distance measure showed significant differences between samples from SYNBIO and CON (P = 0.02). However, by analyzing principal coordinates analysis (PCoA) with unweighted Unifrac, there was no evidence of clustering between CON and probiotic treatments. By 42d, there were no differences in alpha or beta-diversity in the microbiota of probiotic treatments compared to CON. Similarly, taxonomic microbial profiling did not show major changes in cecal microbial taxa. In conclusion, not all probiotic-based formulations tested had a core benefit on the modulation of microbiota. However, based on the quantitative beta diversity results, SYNBIO greatly influenced the cecal microbial community structure attributable to transient variations in relative taxon abundance.

Intestinal Pioneer Colonizers as Drivers of Ileal Microbial Composition and Diversity of Broiler Chickens.

Given that recent advances in metagenomics have highlighted the importance of intestinal microbes for poultry health, there has been a corresponding search for early manipulation strategies of intestinal microbiota in order to advance immune system development and optimize functional properties of growth. In this study, we used the in ovo technique as an experimental model to address how early bacterial intestinal colonization could affect the development and establishment of the mature ileal microbiota. Inoculations containing one of the following: 0.2 mL of 0.9% sterile saline (S), approximately 102 cells of Citrobacter freundii (CF), Citrobacter species (C2) or lactic acid bacteria mixture (L) were administered via in ovo into the amnion. Results showed that Enterobacteriaceae abundance was negatively correlated with aging, although its high population at day of hatch affected the microbiota composition, delaying mature microbiota establishment. L treatment increased colonization of butyrate-producing bacteria by 3 and 10 days, and segmented filamentous bacteria in the lower ileum by 10 days. On the other hand, L-probiotic decreased the population of Enterococcaceae. In addition, L and C2 microbial communities were less diverse at 10 than 3 days of age in the upper ileum. Importantly, these findings provide a valuable resource for a potential study model for interactions between microbial colonization and associated immune responses. In conclusion, our analysis demonstrates that intestinal pioneer colonizers play a critical role in driving the course of microbial community composition and diversity over time, in which early life exposure to L-based probiotic supported selection alongside greater colonization of symbiotic populations in the ileum of young broilers.

Crude Inactivated Influenza A Virus Adjuvated with a Bispecific Antibody Complex Targeting Chicken CD40 and AIV M2e Confers Protection Against Lethal HPAI Challenge in Chickens.

In vivo targeting an immunogen to the CD40 receptor expressed on professional antigen-presenting cells (APCs) dramatically enhances speed, magnitude, and quality of the immune response. Our previous evaluation of this strategy in poultry was limited to immunogenicity studies using CD40-targeted synthetic peptides, which demonstrated significant antigen-specific serum IgG and tracheal IgA levels <1 week after primary administration. In this study, this antibody-guided immunization strategy was modified to permit incorporation of inactivated highly pathogenic avian influenza virions (in lieu of short synthetic peptides) as the immunogen by simply mixing a bispecific antibody complex (anti-CD40/M2e) with crude inactivated virus before injection. Adjuvated avian influenza virus (AIV) induced significant hemagglutination inhibition titers up to 6 weeks postimmunization. In efficacy studies, administration of a single vaccine dose yielded 56%-64% survival against challenge with highly pathogenic H5N1, and 100% protection was achieved upon boosting. These results represent a feasible strategy to effectively target whole inactivated influenza A virus to chicken APCs, regardless of AIV clade and without phenotyping or purifying the virus from crude allantoic fluid. The data represent proof of principle for the unique prophylactic efficacy and versatility of a CD40-targeting adjuvation strategy that can in principle also be harnessed in other poultry vaccines.

Hooke's law: applications of a recurring principle.

Students generally approach topics in physiology as a series of unrelated phenomena that share few underlying principles. However, if students recognized that the same underlying principles can be used to explain many physiological phenomena, they may gain a more unified understanding of physiological systems. To address this concern, we developed a simple, inexpensive, and easy to build model to demonstrate the underlying principles regarding Starling's Law of the Heart as well as lung and arterial elastic recoil. A model was chosen because models significantly enhance student understanding. Working with models also encourages research-oriented learning and helps our students understand complex ideas. Students are drawn into discussion by the power of learning that is associated with manipulating and thinking about objects. Recognizing that the same underlying principles can be used to explain many physiological phenomena may help students gain a more complete understanding of physiological systems.

A model of locomotor-respiratory coupling in quadrupeds.

Locomotion and respiration are not independent phenomena in running mammals because locomotion and respiration both rely on cyclic movements of the ribs, sternum, and associated musculature. Thus, constraints are imposed on locomotor and respiratory function by virtue of their linkage. Specifically, locomotion imposes mechanical constraints on breathing that require the respiratory cycle to be synchronized with gait. Thus, many mammals, including humans, synchronize respiration with the movement of the limbs during locomotion. For example, quadrupeds synchronize locomotor and respiratory cycles at a 1:1 ratio (stride/breath) over a wide range of speeds. Interestingly, quadrupeds maintain an almost constant stride frequency (and therefore respiratory frequency) at different speeds. To increase speed, quadrupeds lengthen their stride. Accordingly, to increase minute ventilation, quadrupeds must increase tidal volume since respiratory rate is coupled with stride frequency. We developed a simple, inexpensive, and easy to build model to demonstrate this concept. A model was chosen because models significantly enhance student understanding. Students are drawn into discussion by the power of learning that is associated with manipulating and thinking about objects. Building and using this model strengthen the concept that locomotor-respiratory coupling provides a basis for the appropriate matching of lung ventilation to running speed and metabolic power.