Strategies to Enhance Cultivation of Anaerobic Bacteria from Gastrointestinal Tract of Chicken.

The gastrointestinal tract (GIT) of chicken is a complex ecosystem harboring trillions of microbes that play a pivotal role in the host's physiology, digestion, nutrient absorption, immune system maturation, and prevention of pathogen intrusion. For optimal animal health and productivity, it is imperative to characterize these microorganisms and comprehend their role. While the GIT of poultry holds a reservoir of microorganisms with potential probiotic applications, most of the diversity remains unexplored. To enhance our understanding of uncultured microbial diversity, concerted efforts are required to bring these microorganisms into culture. Isolation and cultivation of GIT-colonizing microorganisms yield reproducible material, including cells, DNA, and metabolites, offering new insights into metabolic processes in the environment. Without cultivation, the role of these organisms in their natural settings remains unclear and limited to a descriptive level. Our objective is to implement cultivation strategies aimed at improving the isolation of a diverse range of anaerobic microbes from the chicken's GIT, leveraging multidisciplinary knowledge from animal physiology, animal nutrition, metagenomics, feed biochemistry, and modern cultivation strategies. Additionally, we aim to implement the use of proper practices for sampling, transportation, and media preparation, which are known to influence isolation success. Appropriate methodologies should ensure a consistent oxygen-free environment, optimal atmospheric conditions, appropriate host incubation temperature, and provision for specific nutritional requirements in alignment with their distinctive needs. By following these methodologies, cultivation will not only yield reproducible results for isolation but will also facilitate isolation procedures, thus fostering a comprehensive understanding of the intricate microbial ecosystem within the chicken's GIT.

Linking Variability in Phytochemical Composition with Safety Profile of Thymus carnosus Boiss. Extracts: Effect of Major Compounds and Evaluation of Markers of Oxidative Stress and Cell Death.

Natural products are generally considered safe for human consumption, but this classification is often based on ethnobotanical surveys or their use in traditional medicine over a long period of time. However, edaphoclimatic factors are known to produce different chemotypes, which may affect the safety profile and bioactivities, and are not commonly considered for plants exploited as crops worldwide. Thymus carnosus Boiss., a thyme species with various health-promoting effects, has potential pharmaceutical applications, but edaphoclimatic factors were found to significantly impact its phytochemical composition. Thus, we aimed to assess the safety profile of T. carnosus extracts obtained from plants harvested in two locations over three consecutive years and to establish an association with specific components, an essential study in the search for new sources of nutraceuticals. Thus, the antiproliferative effect of an aqueous decoction (AD), hydroethanolic (HE) extracts, and major extracts' components of T. carnosus was evaluated on intestinal (Caco-2) and hepatic (HepG2) cell models, revealing effects dependent on extract type, cell line, and tested compounds. Flavonoids induced different cytotoxic patterns, which could be attributed to molecular structural differences. Flow cytometry analysis showed apoptosis and necrosis induction, mediated by the modulation of intracellular reactive oxygen species and mitochondrial membrane potential, effects that were dependent on the cell line and phytochemical composition and on the synergism between extracts components, rather than on the activity of an isolated compound. While ursolic acid was the component with the strongest impact on the difference between extraction methods, flavonoids assumed a pivotal role in the response of different cell lines to the extracts. We report for the first time, for Thymus spp. extracts, that variations in the phytochemical composition clearly influence the cellular response, thus highlighting the need for extract standardization for medicinal applications.

Labdanum Resin from Cistus ladanifer L. as a Source of Compounds with Anti-Diabetic, Neuroprotective and Anti-Proliferative Activity.

Labdanum resin or "gum" can be obtained from Cistus ladanifer L. by two different extraction methods: the Zamorean and the Andalusian processes. Although its main use is in the fragrance and perfumery sectors, ethnobotanical reports describe its use for medicinal purposes in managing hyperglycemia and mental illnesses. However, data concerning the bioactivities and pharmacological applications are scarce. In this work, it was found that the yield of labdanum resin extracted by the Andalusian process was 25-fold higher than the Zamorean one. Both resins were purified as absolutes, and the Andalusian absolute was purified into diterpenoid and flavonoid fractions. GC-EI-MS analysis confirmed the presence of phenylpropanoids, labdane-type diterpenoids, and methylated flavonoids, which are already described in the literature, but revealed other compounds, and showed that the different extracts presented distinct chemical profile. The potential antidiabetic activity, by inhibition of α-amylase and α-glucosidase, and the potential neuroprotective activity, by inhibition of acetylcholinesterase, were investigated. Diterpenoid fraction produced the higher α-amylase inhibitory effect (~30% and ~40% at 0.5 and 1 mg/mL, respectively). Zamorean absolute showed the highest α-glucosidase inhibitory effect (~14% and ~24%, at 0.5 and 1 mg/mL, respectively). Andalusian absolute showed the highest acetylcholinesterase inhibitory effect (~70% and ~75%, at 0.5 and 1 mg/mL, respectively). Using Caco-2 and HepG2 cell lines, Andalusian absolute and its purified fractions showed moderate cytotoxic/anti-proliferative activity at 24 h exposure (IC50 = 45-70 µg/mL, for Caco-2; IC50 = 60-80 µg/mL, for HepG2), whereas Zamorean absolute did not produce cytotoxicity (IC50 ≥ 200.00 µg/mL). Here we show, for the first time, that labdanum resin obtained by the Andalusian process, and its fractions, are composed of phytochemicals with anti-diabetic, neuroprotective and anti-proliferative potential, which are worth investigating for the pharmaceutical industry. However, toxic side-effects must also be addressed when using these products by ingestion, as done traditionally.

Microbial signatures and enterotype clusters in fattening pigs: implications for nitrogen utilization efficiency.

As global demand for pork continues to rise, strategies to enhance nitrogen utilization efficiency (NUE) in pig farming have become vital for environmental sustainability. This study explored the relationship between the fecal microbiota, their metabolites, and NUE in crossbreed fattening pigs with a defined family structure. Pigs were kept under standardized conditions and fed in a two-phase feeding regime. In each phase, one fecal sample was collected from each pig. DNA was extracted from a total of 892 fecal samples and subjected to target amplicon sequencing. The results indicated an influence of sire, sampling period (SP), and sex on the fecal microbiota. Streptococcus emerged as a potential biomarker in comparing high and low NUE pigs in SP 1, suggesting a genetic predisposition to NUE regarding the fecal microbiota. All fecal samples were grouped into two enterotype-like clusters named cluster LACTO and cluster CSST. Pigs' affiliation with enterotype-like clusters altered over time and might be sex-dependent. The stable cluster CSST demonstrated the highest NUE despite containing pigs with lower performance characteristics such as average daily gain, dry matter intake, and daily nitrogen retention. This research contributes with valuable insights into the microbiome's role in NUE, paving the way for future strategies to enhance sustainable pig production.

Squid meal and shrimp hydrolysate as novel protein sources for dog food.

The world's growing pet population is raising sustainability and environmental concerns for the petfood industry. Protein-rich marine by-products might contribute to mitigating negative environmental effects, decreasing waste, and improving economic efficiency. The present study evaluated two marine by-products, squid meal and shrimp hydrolysate, as novel protein sources for dog feeding. Along with the analysis of chemical composition and antioxidant activity, palatability was evaluated by comparing a commercial diet (basal diet) and diets with the inclusion of 150 g kg-1 of squid meal or shrimp hydrolysate using 12 Beagle dogs (2.2 ± 0.03 years). Two in vivo digestibility trials were conducted with six dogs, three experimental periods (10 days each) and three dietary inclusion levels (50, 100 and 150 g kg-1) of squid meal or shrimp hydrolysate in place of the basal diet to evaluate effects of inclusion level on apparent total tract digestibility (ATTD), metabolizable energy content, fecal characteristics, metabolites, and microbiota. Both protein sources presented higher protein and methionine contents than ingredients traditionally used in dog food formulation. Shrimp hydrolysate showed higher antioxidant activity than squid meal. First approach and taste were not affected by the inclusion of protein sources, but animals showed a preference for the basal diet. Effects on nutrient intake reflected the chemical composition of diets, and fecal output and characteristics were not affected by the increasing inclusion levels of both protein sources. The higher ATTD of dry matter, most nutrients and energy of diets with the inclusion of both by-products when compared to the basal diet, suggests their potential to be included in highly digestible diets for dogs. Although not affected by the inclusion level of protein sources, when compared to the basal diet, the inclusion of squid meal decreased butyrate concentration and shrimp hydrolysate increased all volatile fatty acids, except butyrate. Fecal microbiota was not affected by squid meal inclusion, whereas inclusion levels of shrimp hydrolysate significantly affected abundances of Oscillosperaceae (UCG-005), Firmicutes and Lactobacillus. Overall, results suggest that squid meal and shrimp hydrolysate constitute novel and promising protein sources for dog food, but further research is needed to fully evaluate their functional value.

Genomic analyses of nitrogen utilization efficiency, its indicator trait blood urea nitrogen and the relationship to classical growth performance and feed efficiency traits in a Landrace × Piétrain crossbred population.

Improving the nutrient efficiency in pork production is required to reduce the resource competition between human food and animal feed regarding diet components edible for humans and to minimize emissions relevant to climate or the environment. Thereby, protein utilization efficiency and its equivalent nitrogen utilization efficiency (NUE) play a major role. Breeding for more nitrogen (N) efficient pigs bears a promising strategy to improve such traits, however, directly phenotyping NUE based on N balance data is neither cost-efficient nor straightforward and not applicable for routine evaluations. Blood urea nitrogen (BUN) levels in the pig are suitable to predict the NUE and, therefore, might be an indicator trait for NUE because BUN is a relatively easy-to-measure trait. This study investigated the suitability of NUE as a selection trait in future breeding programs. The relationships to classical growth performance and feed efficiency traits were analysed as well as the relationship to BUN to infer the role of BUN as an indicator trait to improve NUE via breeding. The analyzes were based on a Landrace F1 cross population consisting of 502 individuals who descended from 20 Piétrain sires. All animals were genotyped for 48,525 SNPs. They were phenotyped in two different fattening phases, i.e., FP1 and FP2, during the experiment. Uni- and bivariate analyses were run to estimate variance components and to determine the genetic correlation between different traits or between the same trait measured at different time points. Moderate heritabilities were estimated for all traits, whereby the heritability for NUE was h2 = 0.293 in FP1 and h2 = 0.163 in FP2 and BUN had the by far highest heritability (h2 = 0.415 in FP1 and h2 = 0.460 in FP2). The significant genetic correlation between NUE and BUN showed the potential of BUN to be considered an indicator trait for NUE. This was particularly pronounced when NUE was measured in FP1 (genetic correlations r g = - 0.631 $$ {r}_g=-0.631 $$ and r g = - 0.688 $$ {r}_g=-0.688 $$ between NUE and BUN measured in FP1 and FP2, respectively). The genetic correlations of NUE and BUN with important production traits suggest selecting pigs with high growth rates and low BUN levels to breed more efficient pigs in future breeding programs.

Microbiota modulation by dietary oat beta-glucan prevents steatotic liver disease progression.

Background & Aims: Changes in gut microbiota in metabolic dysfunction-associated steatotic liver disease (MASLD) are important drivers of disease progression towards fibrosis. Therefore, reversing microbial alterations could ameliorate MASLD progression. Oat beta-glucan, a non-digestible polysaccharide, has shown promising therapeutic effects on hyperlipidemia associated with MASLD, but its impact on gut microbiota and most importantly MASLD-related fibrosis remains unknown. Methods: We performed detailed metabolic phenotyping, including assessments of body composition, glucose tolerance, and lipid metabolism, as well as comprehensive characterization of the gut-liver axis in a western-style diet (WSD)-induced model of MASLD and assessed the effect of a beta-glucan intervention on early and advanced liver disease. Gut microbiota were modulated using broad-spectrum antibiotic treatment. Results: Oat beta-glucan supplementation did not affect WSD-induced body weight gain or glucose intolerance and the metabolic phenotype remained largely unaffected. Interestingly, oat beta-glucan dampened MASLD-related inflammation, which was associated with significantly reduced monocyte-derived macrophage infiltration and fibroinflammatory gene expression, as well as strongly reduced fibrosis development. Mechanistically, this protective effect was not mediated by changes in bile acid composition or signaling, but was dependent on gut microbiota and was lost upon broad-spectrum antibiotic treatment. Specifically, oat beta-glucan partially reversed unfavorable changes in gut microbiota, resulting in an expansion of protective taxa, including Ruminococcus, and Lactobacillus followed by reduced translocation of Toll-like receptor ligands. Conclusions: Our findings identify oat beta-glucan as a highly efficacious food supplement that dampens inflammation and fibrosis development in diet-induced MASLD. These results, along with its favorable dietary profile, suggest that it may be a cost-effective and well-tolerated approach to preventing MASLD progression and should be assessed in clinical studies. Impact and Implications: Herein, we investigated the effect of oat beta-glucan on the gut-liver axis and fibrosis development in a mouse model of metabolic dysfunction-associated steatotic liver disease (MASLD). Beta-glucan significantly reduced inflammation and fibrosis in the liver, which was associated with favorable shifts in gut microbiota that protected against bacterial translocation and activation of fibroinflammatory pathways. Together, oat beta-glucan may be a cost-effective and well-tolerated approach to prevent MASLD progression and should be assessed in clinical studies.

The Impact of 8 Weeks of Combined Physical Exercise Training on SIRT3 and mTOR in Lymphocytes, and on Lipid Peroxidation.

The sirtuins (SIRT) protein family and the mechanistic/mammalian target of rapamycin (mTOR) are intracellular molecules that have been involved in the regulation of several biological processes, as well as in various aging-related processes. This pilot study, in small scale, aimed to analyze the effects of an 8-week physical exercise program on SIRT3 and mTOR levels in lymphocytes, as well as on lipid peroxidation in middle aged and older men. A total of 9 participants aged between 56 and 73 years were enrolled in an 8-week physical exercise program comprising cardiovascular and high-intensity interval training. The program involved three sessions per week, each lasting 45-60 min, conducted on non-consecutive days. Tests were conducted before and after the experimental period (pre- and post-training). Assessments included a vertical jump, 20 m velocity, ball throwing, and an aerobic capacity test. Lipid peroxidation (MDA) was measured in plasma as an oxidative stress biomarker. Additionally, sirtuin 3 (SIRT3/ß-actin) and mTOR (mTOR/ß-actin) levels were measured in isolated lymphocytes extracted from venous blood. Following the exercise training period, our results demonstrated a significant improvement in aerobic capacity (pre-training: 615.4 ± 45.3 m; post-training: 687.2 ± 34.6 m; t = -2.521; p = 0.012) and 20 m velocity (pre-training: 4.6 ± 0.5 s; post-training: 4.3 ± 0.3 s; t = -2.023; p = 0.04). Concerning blood variables, there was a significant decrease in mTOR levels (pre-training: 0.857 ± 0.593; post-training: 0.214 ± 0.097; t = -2.547; p = 0.011), while no changes were observed in SIRT3 (pre-training: 0.608 ± 0.404; post-training: 0.516 ± 0.390; t = 0.533; p = 0.594) and MDA (pre-training: 8420 ± 4615; post-training: 8800 ± 3163; t = -0.533; p = 0.594). The notable reduction in mTOR levels in lymphocytes following the 8-week physical exercise program suggests a potential role of exercise in modulating immune cell dynamics, particularly in middle-aged and older individuals. Furthermore, the exercise regimen resulted in improvements in physical function, including enhanced aerobic capacity and walking velocity.

Natural Products as Dietary Agents for the Prevention and Mitigation of Oxidative Damage and Inflammation in the Intestinal Barrier.

Food intake is a basic need to sustain life, but foodborne pathogens and food-related xenobiotics are also the main health concerns regarding intestinal barrier homeostasis. With a predominant role in the well-being of the entire human body, intestinal barrier homeostasis is strictly regulated by epithelial and immune cells. These cells are also the main intervenients in oxidative stress and inflammation-related diseases in the intestinal tract, triggered, for example, by genetic/epigenetic factors, food additives, pesticides, drugs, pathogens, and their metabolites. Nevertheless, the human diet can also be seen as a solution for the problem, mainly via the inclusion of functional foods or nutraceuticals that may act as antioxidant/anti-inflammatory agents to prevent and mitigate acute and chronic oxidative damage and inflammation. A literature analysis of recent advances in this topic highlights the significant role of Nrf2 (nuclear factor erythroid 2-related factor 2) and NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) pathways in these biological processes, with many natural products and phytochemicals targeting endogenous antioxidant systems and cytokine production and balance. In this review, we summarized and discussed studies using in vitro and in vivo models of the intestinal tract used to reproduce oxidative damage and inflammatory events, as well as the role of natural products as modulators of Nrf2 and NK-kB pathways.

Antibiotics attenuate diet-induced nonalcoholic fatty liver disease without altering intestinal barrier dysfunction.

To date the role of the alterations of intestinal microbiota in the development of intestinal barrier dysfunction in settings of nonalcoholic fatty liver disease (NAFLD) has not been fully understood. Here, we assessed the effect of antibiotics on development of NAFLD and their impact on intestinal barrier dysfunction. Male C57BL/6J mice were either pair-fed a liquid control diet (C) or fat- and fructose-rich diet (FFr) +/- antibiotics (AB, ampicillin/vancomycin/metronidazole/gentamycin) for 7 weeks. Fasting blood glucose was determined and markers of liver damage, inflammation, intestinal barrier function, and microbiota composition were assessed. The development of hepatic steatosis with early signs of inflammation found in FFr-fed mice was significantly abolished in FFr+AB-fed mice. Also, while prevalence of bacteria in feces was not detectable and TLR4 ligand levels in portal plasma were at the level of controls in FFr+AB-fed mice, impairments of intestinal barrier function like an increased permeation of xylose and iNOS protein levels persisted to a similar extent in both FFr-fed groups irrespective of AB use. Exposure of everted small intestinal tissue sacs of naïve mice to fructose resulted in a significant increase in tissue permeability and loss of tight junction proteins, being not affected by the presence of AB, whereas the concomitant treatment of tissue sacs with the NOS inhibitor aminoguanidine attenuated these alterations. Taken together, our data suggest that intestinal barrier dysfunction in diet-induced NAFLD in mice may not be predominantly dependent on changes in intestinal microbiota but rather that fructose-induced alterations of intestinal NO-homeostasis might be critically involved.

Supplementing L-Citrulline Can Extend Lifespan in C. elegans and Attenuate the Development of Aging-Related Impairments of Glucose Tolerance and Intestinal Barrier in Mice.

L-Citrulline (L-Cit) is discussed to possess a protective effect on intestinal barrier dysfunction but also to diminish aging-associated degenerative processes. Here, the effects of L-Cit on lifespan were assessed in C. elegans, while the effects of L-Cit on aging-associated decline were determined in C57BL/6J mice. For lifespan analysis, C. elegans were treated with ±5 mM L-Cit. Twelve-month-old male C57BL/6J mice (n = 8-10/group) fed a standard chow diet received drinking water ± 2.5 g/kg/d L-Cit or 5 g/kg/d hydrolyzed soy protein (Iso-N-control) for 16 or 32 weeks. Additionally, 4-month-old C57BL/6J mice were treated accordingly for 8 weeks. Markers of senescence, glucose tolerance, intestinal barrier function, and intestinal microbiota composition were analyzed in mice. L-Cit treatment significantly extended the lifespan of C. elegans. The significant increase in markers of senescence and signs of impaired glucose tolerance found in 16- and 20-month-old control mice was attenuated in L-Cit-fed mice, which was associated with protection from intestinal barrier dysfunction and a decrease in NO2- levels in the small intestine, while no marked differences in intestinal microbiota composition were found when comparing age-matched groups. Our results suggest that pharmacological doses of L-Cit may have beneficial effects on lifespan in C. elegans and aging-associated decline in mice.

Microbiota and Nutrient Portraits of European Roe Deer (Capreolus capreolus) Rumen Contents in Characteristic Southern German Habitats.

Roe deer (Capreolus capreolus) are found in various habitats, from pure forest cultures to agricultural areas and mountains. In adapting to the geographically and seasonally differentiating food supply, they depend, above all, on an adapted microbiome. However, knowledge about the microbiome of wild ruminants still needs to be improved. There are only a few publications for individual species with a low number of samples. This study aims to identify a core microbiota for Bavarian roe deer and present nutrient and microbiota portraits of the individual habitat types. This study investigated the roe deer's rumen (reticulorumen) content from seven different characteristic Bavarian habitat types. The focus was on the composition of nutrients, fermentation products, and the rumen bacterial community. A total of 311 roe deer samples were analysed, with the most even possible distribution per habitat, season, age class, and gender. Significant differences in nutrient concentrations and microbial composition were identified for the factors habitat, season, and age class. The highest crude protein content (plant protein and microbial) in the rumen was determined in the purely agricultural habitat (AG), the highest value of non-fibre carbohydrates in the alpine mountain forest, and the highest fibre content (neutral detergent fibre, NDF) in the pine forest habitat. Maximum values for fibre content go up to 70% NDF. The proportion of metabolites (ammonia, lactate, total volatile fatty acids) was highest in the Agriculture-Beech-Forest habitat (ABF). Correlations can be identified between adaptations in the microbiota and specific nutrient concentrations, as well as in strong fluctuations in ingested forage. In addition, a core bacterial community comprising five genera could be identified across all habitats, up to 44% of total relative abundance. As with all wild ruminants, many microbial genera remain largely unclassified at various taxonomic levels. This study provides a more in-depth insight into the diversity and complexity of the roe deer rumen microbiota. It highlights the key microorganisms responsible for converting naturally available nutrients of different botanical origins.

The AnimalAssociatedMetagenomeDB reveals a bias towards livestock and developed countries and blind spots in functional-potential studies of animal-associated microbiomes.

BACKGROUND: Metagenomic data can shed light on animal-microbiome relationships and the functional potential of these communities. Over the past years, the generation of metagenomics data has increased exponentially, and so has the availability and reusability of data present in public repositories. However, identifying which datasets and associated metadata are available is not straightforward. We created the Animal-Associated Metagenome Metadata Database (AnimalAssociatedMetagenomeDB - AAMDB) to facilitate the identification and reuse of publicly available non-human, animal-associated metagenomic data, and metadata. Further, we used the AAMDB to (i) annotate common and scientific names of the species; (ii) determine the fraction of vertebrates and invertebrates; (iii) study their biogeography; and (iv) specify whether the animals were wild, pets, livestock or used for medical research. RESULTS: We manually selected metagenomes associated with non-human animals from SRA and MG-RAST.  Next, we standardized and curated 51 metadata attributes (e.g., host, compartment, geographic coordinates, and country). The AAMDB version 1.0 contains 10,885 metagenomes associated with 165 different species from 65 different countries. From the collected metagenomes, 51.1% were recovered from animals associated with medical research or grown for human consumption (i.e., mice, rats, cattle, pigs, and poultry). Further, we observed an over-representation of animals collected in temperate regions (89.2%) and a lower representation of samples from the polar zones, with only 11 samples in total. The most common genus among invertebrate animals was Trichocerca (rotifers). CONCLUSION: Our work may guide host species selection in novel animal-associated metagenome research, especially in biodiversity and conservation studies. The data available in our database will allow scientists to perform meta-analyses and test new hypotheses (e.g., host-specificity, strain heterogeneity, and biogeography of animal-associated metagenomes), leveraging existing data. The AAMDB WebApp is a user-friendly interface that is publicly available at https://webapp.ufz.de/aamdb/ .

Effects of microalgae as dietary supplement on palatability, digestibility, fecal metabolites, and microbiota in healthy dogs.

The current trend of dog owners increasingly favoring the functional value of food to assure preventive health and wellbeing of their pets has been raising the interest in microalgae as natural additives with bioactive properties. However, scientific studies addressing the effects of microalgae supplementation in diets for dogs are scarce. This study aimed to evaluate the effects of dietary supplementation with three microalgae species (Chlorella vulgaris, Nannochloropsis oceanica, and Tetradesmus obliquus) on diet palatability, total tract digestibility, metabolizable energy content, fecal metabolites and microbiota of dogs. Twelve adult Beagle dogs were used in three two-bowl tests to compare the palatability of a commercial complete diet for adult dogs without (reference diet) and with 1.5% supplementation of each microalgae. From the results obtained, three digestibility trials were performed according to a replicated Latin square 3 × 3, with six adult Beagle dogs, three experimental periods of 10 days each, and three dietary supplementation levels of microalgae (0.5, 1.0, and 1.5%). In each trial, effects of microalgae supplementation levels on total tract digestibility, metabolizable energy content, fecal metabolites and microbiota of dogs were evaluated. First diet approached or tasted was not significantly affected by microalgae inclusion, but dogs showed a preference for the reference diet over the diets with 1.5% inclusion of C. vulgaris and N. oceanica, no difference being observed with 1.5% T. obliquus. In all digestibility trials, dietary supplementation with microalgae up to 1.5% did not greatly affected the dietary chemical composition and kept unaffected food intake, fecal output and metabolites, and digestibility of nutrients and energy. Compared with the reference diet, supplementation with C. vulgaris increased protein digestibility. Fecal characteristics and metabolites were affected by microalgae supplementation, being the effects dependent on the species. Fecal microbiota composition of dogs fed with microalgae-supplemented diets was modified by promoting the beneficial Turicibacter and Peptococcus genera associated with gut health and activation of the immune system. Overall, the results support C. vulgaris, N. oceanica, and T. obliquus as sustainable functional supplements that potentially enhance gastrointestinal health of dogs through the selective stimulation of microbiota without detrimental effects on food intake and digestibility.

"Get the best out of what comes in" - adaptation of the microbiota of chamois (Rupicapra rupicapra) to seasonal forage availability in the Bavarian Alps.

As an inhabitant of the Alps, chamois are exposed to significant climatic changes throughout the year and are also strongly confronted with changing forage availability. Besides horizontal and vertical migratory movements as an adaptation, it undergoes physiological transformations and dynamic changes in the ruminal microbiota. The following study used 48 chamois of different ages and genders to investigate to which extent the ingested food plants, the resulting crude nutrients in the rumen (reticulorumen) contents, and the bacterial microbiota in the rumen and their fermentation products were influenced by the changes over the seasons. Very little is known about the microbiota of wild ruminants, and many bacterial taxa could only be determined to certain taxonomic levels in this study. However, adapted microbiota reflects the significant changes in the ingested forage and the resulting crude nutrients. For some taxa, our results indicated potential functional relationships. In addition, 15 genera were identified, representing almost 90% of the relative abundance, forming the central part of the microbial community throughout the year. The successful and flexible adaptation of chamois is reflected in the chamois rumen's nutrient and microbial profile. This is also the first study that analyzes the microbiota of the chamois using rumen samples and considers the microbiota in a seasonal comparison.

Cognitive Alterations in Old Mice Are Associated with Intestinal Barrier Dysfunction and Induced Toll-like Receptor 2 and 4 Signaling in Different Brain Regions.

Emerging evidence implicate the 'microbiota-gut-brain axis' in cognitive aging and neuroinflammation; however, underlying mechanisms still remain to be elucidated. Here, we assessed if potential alterations in intestinal barrier function and microbiota composition as well as levels of two key pattern-recognition receptors namely Toll-like receptor (TLR) 2 and TLR4, in blood and different brain regions, and depending signaling cascades are paralleling aging associated alterations of cognition in healthy aging mice. Cognitive function was assessed in the Y-maze and intestinal and brain tissue and blood were collected in young (4 months old) and old (24 months old) male C57BL/6 mice to determine intestinal microbiota composition by Illumina amplicon sequencing, the concentration of TLR2 and TLR4 ligands in plasma and brain tissue as well as to determine markers of intestinal barrier function, senescence and TLR2 and TLR4 signaling. Cognitive function was significantly impaired in old mice. Also, in old mice, intestinal microbiota composition was significantly altered, while the relative abundance of Gram-negative or Gram-positive bacteria in the small and large intestines at different ages was not altered. Moreover, intestinal barrier function was impaired in small intestine of old mice, and the levels of TLR2 and TLR4 ligands were also significantly higher in both portal and peripheral blood. Furthermore, levels of TLR2 and TLR4 ligands, and downstream markers of TLR signaling were higher in the hippocampal and prefrontal cortex of old mice compared to young animals. Taken together, our results suggest that even in 'healthy' aging, cognitive function is impaired in mice going along with an increased intestinal translocation of TLR ligands and alterations of TLR signaling in several brain regions.

Host specific adaptations of Ligilactobacillus aviarius to poultry.

The genus Ligilactobacillus encompasses species adapted to vertebrate hosts and fermented food. Their genomes encode adaptations to the host lifestyle. Reports of gut microbiota from chicken and turkey gastrointestinal tract have shown a high persistence of Ligilactobacillus aviarius along the digestive system compared to other species found in the same host. However, its adaptations to poultry as a host has not yet been described. In this work, the pan-genome of Ligilactobacillus aviarius was explored to describe the functional adaptability to the gastrointestinal environment. The core genome is composed of 1179 gene clusters that are present at least in one copy that codifies to structural, ribosomal and biogenesis proteins. The rest of the identified regions were classified into three different functional clusters of orthologous groups (clusters) that codify carbohydrate metabolism, envelope biogenesis, viral defence mechanisms, and mobilome inclusions. The pan-genome of Ligilactobacillus aviarius is a closed pan-genome, frequently found in poultry and highly prevalent across chicken faecal samples. The genome of L. aviarius codifies different clusters of glycoside hydrolases and glycosyltransferases that mediate interactions with the host cells. Accessory features, such as antiviral mechanisms and prophage inclusions, variate amongst strains from different GIT sections. This information provides hints about the interaction of this species with viral particles and other bacterial species. This work highlights functional adaptability traits present in L. aviarius that make it a dominant key member of the poultry gut microbiota and enlightens the convergent ecological relation of this species to the poultry gut environment.

Nitrogen and lysine utilization efficiencies, protein turnover, and blood urea concentrations in crossbred grower pigs at marginal dietary lysine concentration.

Nitrogen utilization efficiency (NUE) and lysine utilization efficiency (LUE) are key indicators of sustainable pork production and vary depending on nutritional and non-nutritional factors. The objective was to study NUE and LUE together with concentrations of blood urea nitrogen (BUN) and other metabolites in growing pigs fed diets with marginal Lys concentrations at 11-13 wk (40.5 kg mean BW) and 14 to 16 wk (60.2 kg mean BW). The cereal grain-soybean meal-based diets contained 10.6 and 7.9 g Lys/kg DM in periods 1 and 2, respectively. Feed intake and BW were measured for 508 individually penned pigs, and blood samples were collected 5 h after morning feeding at weeks 13 and 16. A subgroup of 48 barrows was used in a nitrogen (N) metabolism trial at weeks 13 and 16. In this subgroup, the mean N retention of pigs (27.3 g N/d) and mean LUE (70%) were not different between the periods, but NUE was higher in period 1 (47%) than in period 2 (43%) (P < 0.001). After administration of a single dose of 15N labeled glycine and measurement of 15N recovery in urine, the calculated whole-body protein turnover did not differ between the periods. The rate of protein synthesis was positively correlated with NUE (P < 0.001), but protein degradation was not. Excretion of urea-N in urine accounted for 80% of the total urinary N and was positively correlated with BUN. The N retention of all 508 pigs was estimated using an equation that was derived from the N metabolism data. N retention was on average 31.4 g/d, equal in both periods, and higher in barrows than in gilts in period 2, but not in period 1 (P = 0.003). The calculated NUE was, on average, 47% and was lower in barrows than in gilts (P < 0.001) and higher in period 1 than in period 2 (P < 0.001). The calculated LUE was, on average, 71%, and was lower in barrows than in gilts in period 2, but not in period 1 (P < 0.001). The BUN concentration was higher in barrows than in gilts (P < 0.001) and higher in period 1 than in period 2 (P < 0.001). BUN concentration was negatively correlated with NUE in Periods 1 (r = -0.50) and 2 (r = -0.15) (P < 0.05). We concluded that the maximum LUE was in the range of 70-72% under the conditions of this study, and only small differences between the periods and sexes existed. Protein synthesis, rather than degradation, appears to affect NUE. BUN concentration may be useful for estimating NUE in a large group of animals fed a diet with a marginal Lys concentration.

Increasing the utilization of protein and amino acids by pigs is an effective tool for improving the sustainability of pork production. This study showed that the utilization of lysine, the limiting amino acid in pigs, can reach 72% in growing pigs aged 11­16 wk when fed diets based on cereal grains and soybean meal. The average utilization of total nitrogen was 47%, with high variation among the pigs. Higher nitrogen utilization was associated with lower concentration of urea in the blood. This indicates that the blood urea concentration is an easy-to-determine proxy trait for nitrogen utilization in pigs when the concentration of lysine in the feed is low. Only small differences were observed between gilts and barrows during the investigation period. Nitrogen utilization increased when pigs had a higher rate of whole-body protein synthesis, which was associated with anabolic hormone concentrations in the blood.

Effect of dietary calcium concentration and exogenous phytase on inositol phosphate degradation, mineral digestibility, and gut microbiota in growing pigs.

Variations in the dietary Ca concentration may affect inositol phosphate (InsP) degradation, and thereby, P digestibility in pigs. This study assessed the effects of dietary Ca concentration and exogenous phytase on InsP degradation, nutrient digestion and retention, blood metabolites, and microbiota composition in growing pigs with ileal cannulation. In a completely randomized row-column design with four periods, eight ileal-cannulated barrows (initial body weight 27 kg) were fed four corn-soybean- and rapeseed meal-based diets containing 5.5 or 8.5 g Ca/kg dry matter (DM), with or without 1,500 FTU of an exogenous hybrid-6-phytase/kg diet. No mineral P was added and the P concentration in the feed was 4.8 g P/kg DM. Prececal InsP6 disappearance in pigs fed diets containing exogenous phytase was lower (P = 0.022) with additional Ca than without. Concentrations of InsP2-4 isomers and myo-inositol in the distal ileal digesta and prececal P digestibility were greater (P < 0.001) with exogenous phytase than without exogenous phytase. In feces, InsP6 disappearance was lower (P < 0.002) and concentration of InsP5 and InsP4 isomers was higher (P ≤ 0.031) with additional Ca compared to without additional Ca. The prececal amino acid digestibility, energy digestibility, and hindgut disappearance of energy did not differ. The Shannon diversity index of the microbiota in the distal ileal digesta and feces was similar among the diets but was lower in the distal ileal digesta than in the feces (P < 0.001). Permutation analysis of variance revealed no dietary differences between the bacterial groups within the ileal digesta and fecal samples (P > 0.05). In conclusion, additional Ca reduced the effect of exogenous phytase on prececal InsP6 degradation. Endogenous InsP degradation was impaired by additional Ca only in the hindgut but the abundance of bacterial genera in feces was not affected.

The dietary calcium concentration can influence the release of phosphorus from phytate in growing pigs. This study assessed the effects of dietary calcium and exogenous phytase on inositol phosphate (InsP) degradation and nutrient digestibility in ileal-cannulated, growing pigs. The phosphorus, calcium, and myo-inositol concentrations in the blood, microbiota composition in the ileal digesta and feces, and volatile fatty acid concentrations in the feces were also evaluated. Additional dietary calcium decreased prececal inositol hexakisphosphate (InsP6) disappearance, but only with exogenous phytase. Concentrations of InsP2-4 isomers and myo-inositol in the ileal digesta and prececal phosphorus digestibility were greater with exogenous phytase, but not affected by dietary calcium concentration. In contrast, fecal InsP6 disappearance was lower and the concentration of InsP4-5 isomers in feces was greater with additional dietary calcium. Regarding microbiota, the Shannon diversity index was lower in ileal digesta than in feces but was unaffected by dietary calcium concentration or exogenous phytase. In conclusion, dietary calcium concentration is relevant for phytate disappearance in feces, but not in the ileal digesta. However, when exogenous phytase is used, the dietary calcium concentration is important because prececal phytate degradation is changed.