Botanicals for Pigs—Peppermint

Botanicals have been proposed as a substitute for antimicrobials in swine diets because of their natural antibacterial activity. Peppermint, a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. Performance of pigs on all treatments was similar, including the positive and negative controls. At the tested inclusion levels (0, 0.5, 2.5, and 5.0%), no statistical advantage existed over the 5-week study when compared with a positive control diet with 50 g/ton Mecadox or with a negative control containing no antibacterial inclusions. Increasing levels of peppermint did not influence the muscle characteristics evaluated

Botanicals for Pigs—Echinacea

Botanicals have been proposed as a substitute for antimicrobials in swine diets because of their natural antibacterial activity. Echinacea, a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. At the tested inclusion levels (0.1, 0.5 and 2.0%) no statistical advantage existed when compared with a positive control diet with 50 g/ton Mecadox or with a negative control containing no antibacterial inclusions. Echinacea-treated pigs exhibited a slight, but not objectionable, off-flavor compared with noninclusion levels. Higher levels of Echinacea inclusions may be required to enhance growth rate and feed efficiency swine production

Botanicals for Pigs—Goldenseal

Various botanical products have been suggested to have beneficial effects as a replacement for manmade chemotherapeutic and antibacterial agents. This study evaluated four levels of goldenseal (0.0 to 1.0%) compared with a control diet control diet containing Mecadox for nursery pigs. Although not performing to the level of the Mecadox control, pigs on the 0.25 and 1.00% goldenseal diets generally performed better than ones on the 0.00 and 0.05% goldenseal diets and were often not statistically different from the Mecadox control pigs. Increasing levels of goldenseal did not influence the muscle characteristics evaluated

Botanicals for Pigs—Garlic

Botanicals have been proposed as a substitute for antimicrobials in swine diets because of their natural antibacterial activity. Garlic, a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. At the tested inclusion levels (0.5, 2.5 and 5%) increasing levels of garlic generally depressed feed intake and average daily gain in nursery pigs and depressed performance compared with the positive control diet with Mecadox. Muscle samples from the garlic-fed pigs all had very objectionable or extremely objectionable off-flavors.

Botanicals as part of an integral value-added pork production system

Selected herbs are known to naturally possess antibacterial and other characteristics that could be useful in animal protein production. Inclusion of these herbs in animal feeds as alternative growth promotion and efficiency stimulants may be able to address some of the current concerns about the possibility of significant antibiotic-resistant bacteria development that stems from drugs currently used at subtherapeutic levels in animal production. Several herbs were tested for their ability to aid animal growth rates and feed efficiency without giving rise to antibiotic-resistant microbes

Microbial strategies for survival in the glass sponge Vazella pourtalesii

Few studies have thus far explored the microbiomes of glass sponges (Hexactinellida). The present study seeks to elucidate the composition of the microbiota associated with the glass sponge Vazella pourtalesii and the functional strategies of the main symbionts. We combined microscopic approaches with metagenome-guided microbial genome reconstruction and amplicon community profiling towards this goal. Microscopic imaging revealed that the host and microbial cells appeared within dense biomass patches that are presumably syncytial tissue aggregates. Based on abundances in amplicon libraries and metagenomic data, SAR324 bacteria, Crenarchaeota, Patescibacteria and Nanoarchaeota were identified as abundant members of the V. pourtalesii microbiome and their genomic potentials were thus analyzed in detail. A general pattern emerged in that the V. pourtalesii symbionts had very small genome sizes in the range of 0.5-2.2 Mb and low GC contents, even below those of seawater relatives. Based on functional analyses of metagenome-assembled genomes (MAGs), we propose two major microbial strategies: the “givers”, namely Crenarchaeota and SAR324, heterotrophs and facultative anaerobes, produce and partly secrete all required amino acids and vitamins. The “takers”, Nanoarchaeota and Patescibacteria, are anaerobes with reduced genomes that tap into the microbial community for resources, e.g., lipids and DNA, likely using pili-like structures. We posit that the existence of microbial cells in sponge syncytia together with the low-oxygen conditions in the seawater environment are factors that shape the unique compositional and functional properties of the microbial community associated with V. pourtalesii . Importance: We investigated the microbial community of V. pourtalesii that forms globally unique, monospecific sponge grounds under low-oxygen conditions on the Scotian Shelf, where it plays a key role for its vulnerable ecosystem. The microbial community was found to be concentrated within biomass patches and is dominated by small cells (<1 μm). MAG analyses showed consistently small genome sizes and low GC contents, which is unusual in comparison to known sponge symbionts. These properties as well as the (facultatively) anaerobic metabolism and a high degree of interdependence between the dominant symbionts regarding amino acid and vitamin synthesis are likely adaptations to the unique conditions within the syncytial tissue of their hexactinellid host and the low-oxygen environment

Resolving structure and function of metaorganisms through a holistic framework combining reductionist and integrative approaches

Current research highlights the importance of associated microbes in contributing to the functioning, health, and even adaptation of their animal, plant, and fungal hosts. As such, we are witnessing a shift in research that moves away from focusing on the eukaryotic host sensu stricto to research into the complex conglomerate of the host and its associated microorganisms (i.e., microbial eukaryotes, archaea, bacteria, and viruses), the so-called metaorganism, as the biological entity. While recent research supports and encourages the adoption of such an integrative view, it must be understood that microorganisms are not involved in all host processes and not all associated microorganisms are functionally important. As such, our intention here is to provide a critical review and evaluation of perspectives and limitations relevant to studying organisms in a metaorganism framework and the functional toolbox available to do so. We note that marker gene-guided approaches that primarily characterize microbial diversity are a first step in delineating associated microbes but are not sufficient to establish proof of their functional relevance. More sophisticated tools and experiments are necessary to reveal the specific functions of associated microbes. This can be accomplished through the study of metaorganisms in less complex environments, the targeted manipulation of microbial associates, or work at the mechanistic level with the toolbox available in model systems. We conclude that the metaorganism framework is a powerful new concept to help provide answers to longstanding biological questions such as the evolution and ecology of organismal complexity and the importance of organismal symbioses to ecosystem functioning. The intricacy of the metaorganism requires a holistic framework combining reductionist and integrative approaches to resolve metaorganism identities and to disclose the various roles that microorganisms play in the biology of their hosts

MyD88-deficient Hydra reveal an ancient function of TLR signaling in sensing bacterial colonizers

Toll-like receptor (TLR) signaling is one of the most important signaling cascades of the innate immune system of vertebrates. Studies in invertebrates have focused on the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, and there is little information regarding the evolutionary origin and ancestral function of TLR signaling. In Drosophila, members of the Toll-like receptor family are involved in both embryonic development and innate immunity. In C. elegans, a clear immune function of the TLR homolog TOL-1 is controversial and central components of vertebrate TLR signaling including the key adapter protein myeloid differentiation primary response gene 88 (MyD88) and the transcription factor NF-κB are not present. In basal metazoans such as the cnidarians Hydra magnipapillata and Nematostella vectensis, all components of the vertebrate TLR signaling cascade are present, but their role in immunity is unknown. Here, we use a MyD88 loss-of-function approach in Hydra to demonstrate that recognition of bacteria is an ancestral function of TLR signaling and that this process contributes to both host-mediated recolonization by commensal bacteria as well as to defense against bacterial pathogens

Bacterial colonization of Hydra hatchlings follows a robust temporal pattern

Animals are colonized by complex bacterial communities. The processes controlling community membership and influencing the establishment of the microbial ecosystem during development are poorly understood. Here we aimed to explore the assembly of bacterial communities in Hydra with the broader goal of elucidating the general rules that determine the temporal progression of bacterial colonization of animal epithelia. We profiled the microbial communities in polyps at various time points after hatching in four replicates. The composition and temporal patterns of the bacterial communities were strikingly similar in all replicates. Distinct features included high diversity of community profiles in the first week, a remarkable but transient adult-like profile 2 weeks after hatching, followed by progressive emergence of a stable adult-like pattern characterized by low species diversity and the preponderance of the Betaproteobacterium Curvibacter. Intriguingly, this process displayed important parallels to the assembly of human fecal communities after birth. In addition, a mathematical modeling approach was used to uncover the organizational principles of this colonization process, suggesting that both, local environmental or host-derived factor(s) modulating the colonization rate, as well as frequency-dependent interactions of individual bacterial community members are important aspects in the emergence of a stable bacterial community at the end of developmen