Effect of high contents of dietary animal-derived protein or carbohydrates on canine faecal microbiota. BMC Vet Res. 2012;8:90. [PMID: 22735212 DOI: 10.1186/1746-6148-8-90]

Large intestinal nutritional and physicochemical parameters from different dog sizes reshape canine microbiota structure and functions in vitro

Different dog sizes are associated with variations in large intestinal physiology including gut microbiota, which plays a key role in animal health. This study aims to evaluate, using the CANIM-ARCOL (Canine Mucosal Artificial Colon), the relative importance of gut microbes versus physicochemical and nutritional parameters of the canine colonic environment in shaping microbiota structure and functions. CANIM-ARCOL was set up to reproduce nutrient availability, bile acid profiles, colonic pH, and transit time from small, medium, or large dogs according to in vivo data, while bioreactors were all inoculated with a fecal sample collected from medium size dogs (n = 2). Applying different dog size parameters resulted in a positive association between size and gas or SCFA production, as well as distinct microbiota profiles as revealed by 16S Metabarcoding. Comparisons with in vivo data from canine stools and previous in vitro results obtained when CANIM-ARCOL was inoculated with fecal samples from three dog sizes revealed that environmental colonic parameters were sufficient to drive microbiota functions. However, size-related fecal microbes were necessary to accurately reproduce in vitro the colonic ecosystem of small, medium, and large dogs. For the first time, this study provides mechanistic insights on which parameters from colonic ecosystem mainly drive canine microbiota in relation to dog size. The CANIM-ARCOL can be used as a relevant in vitro platform to unravel interactions between food or pharma compounds and canine colonic microbiota, under different dog size conditions. The potential of the model will be extended soon to diseased situations (e.g. chronic enteropathies or obesity).

Using meta-analysis to understand the impacts of dietary protein and fat content on the composition of fecal microbiota of domestic dogs (Canis lupus familiaris): A pilot study

The interplay between diet and fecal microbiota composition is garnering increased interest across various host species, including domestic dogs. While the influence of dietary macronutrients and their associated microbial communities have been extensively reviewed, these reviews are descriptive and do not account for differences in microbial community analysis, nor do they standardize macronutrient content across studies. To address this, a meta-analysis was performed to assess the impact of dietary crude protein ("protein") and dietary crude fat ("fat") on the fecal microbiota composition in healthy dogs. Sixteen publications met the eligibility criteria for the meta-analysis, yielding a final data set of 314 dogs. Diets were classed as low, moderate, high, or supra in terms of protein or fat content. Sequence data from each publication were retrieved from public databases and reanalyzed using consistent bioinformatic pipelines. Analysis of community diversity indices and unsupervised clustering of the data with principal coordinate analysis revealed a small effect size and complete overlap between protein and fat levels at the overall community level. Supervised clustering through random forest analysis and partial least squares-discriminant analysis indicated alterations in the fecal microbiota composition at a more individual taxonomic level, corresponding to the levels of protein or fat. The Prevotellaceae Ga6A1 group and Enterococcus were associated with increasing levels of protein, while Allobaculum and Clostridium sensu stricto 13 were associated with increasing levels of fat. Interestingly, the random forest analyses revealed that Sharpea, despite its low relative abundance in the dog's fecal microbiome, was primarily responsible for the separation of the microbiome for both protein and fat. Future research should focus on validating and understanding the functional roles of these relatively low-abundant genera.

The effects of galacto-oligosaccharides on faecal parameters in healthy dogs and cats

The aim of this study was to evaluate the effects of galacto-oligosaccharides (GOS) on faecal parameters in healthy dogs and cats. To this end, 20 dogs and 20 Domestic shorthair cats were fed a commercially available adult dog food, or cat food, respectively, with either syrup containing GOS (at 1% w galacto-oligosaccharides/w formulated feed) on top (test group) or no topping (control group) for 56 days in a cross-over design. The study consisted of 2 periods of 24 days adaptation, followed by 4 days of collection of faeces. Faecal samples were tested for moisture, nitrogen, pH, macronutrients, enzymes, and fermentation products. The faecal microbiota were analysed by 16S rDNA profiling. It appeared that GOS have different effects in dogs compared to cats. In dogs, the addition of GOS resulted in increased carbohydrate fermentation (increase of acetic and butyric acid), whereas in cats GOS resulted in increased amino acid fermentation (increase of isovaleric acid). The α-diversity of the canine faecal microbiota was reduced by dietary GOS (Inverse Simpson Index, p = 0.063; Shannon index, p = 0.035) whereas the α-diversity of cat faecal microbiota was unaffected (Inverse Simpson Index, p = 0.539; Shannon index, p = 0.872). Lachnospiraceae spp. and Bifidobacterium spp. positively responded to GOS in both cats and dogs. Lactobacillus spp. and Enterobacteriaceae spp. positively responded to GOS in dogs. In both dogs and cats, GOS may therefore improve stool microbiota and result in the production of specific metabolites that are beneficial to gut health.

Faecal metabolome responses to an altered dietary protein:carbohydrate ratio in adult dogs

High-protein diets may aid weight loss and weight maintenance programs in both humans and dogs, although the effect of dietary protein levels on gut metabolism and functionality has not been studied in depth. The current study aimed to investigate the effect of an altered dietary protein:carbohydrate ratio on gut function in adult dogs by means of faecal metabolomic fingerprinting. More specifically, functional metabolic differences in dogs fed a high-protein/low-carbohydrate (HPLC) vs. low-protein/high-carbohydrate (LPHC) diet were studied by equally allocating twelve clinically healthy (6 lean and 6 obese) Beagles into two groups in a cross-over design, with each group receiving two isocaloric diets for four weeks. The faecal metabolome revealed that different protein:carbohydrate ratio can influence host and/or gut microbiome metabolism and function, while no effect was observed on the body condition. Targeted analysis demonstrated that the HPLC diet significantly increased the concentration of indole, spermidine, and pipecolinic acid and decreased the concentration of azelaic acid, D-fructose, mannose, and galactose (p < 0.05). Multivariate modelling (OPLS-DA) of the untargeted faecal metabolome revealed distinctly different metabolomic profiles following the HPLC vs. LPHC diet, with 18 altered pathways. The HPLC diet influenced amino acid and lipid metabolism, potentially promoting weight loss and immune function, whereas the LPHC diet affected carbohydrate fermentation and may promote anti-oxidative function.

Effects of rye inclusion in dog food on fecal microbiota and short-chain fatty acids

BACKGROUND

Rye intake has been associated with beneficial effects on health in human interventions, possibly due to dietary fiber in rye. In dogs, few studies have explored the effects on health of dietary fiber in general, and rye fiber in particular. The aim of this study was to investigate how inclusion of rye, compared with wheat, influenced fecal microbiota composition, short chain fatty acids (SCFA) and apparent total tract digestibility (ATTD) in dogs. Six male Beagle dogs (mean age 4.6 years, SEM 0.95 years; mean body weight 14.6 kg, SEM 0.32 kg) were fed three experimental diets, each for 21 days, including an adaptation period of six days and with 2-2.5 months between diet periods. The diets were similar regarding energy and protein, but had different carbohydrate sources (refined wheat (W), whole grain rye (R), or an equal mixture of both (RW)) comprising 50% of total weight on a dry matter (DM) basis. The diets were baked and titanium dioxide was added for ATTD determination. Fecal samples were collected before and in the end of each experimental period. Fecal microbiota was analyzed by sequencing 16S rRNA gene amplicons and fecal SCFA by high-performance liquid chromatography. Crude protein, crude fat, neutral detergent fiber, and gross energy (GE) in food and feces were analyzed and ATTD of each was determined. Univariate and multivariate statistical methods were applied in data evaluation.

RESULTS

Faecal microbiota composition, differed depending on diet (P = 0.002), with samples collected after consumption of the R diet differing from baseline. This was primarily because of a shift in proportion of Prevotella, which increased significantly after consumption of the R diet (P < 0.001). No significant differences were found for SCFA, but there was a tendency (P < 0.06) for higher molar proportions of acetic acid following consumption of the R diet. The ATTD of crude protein, crude fat, neutral detergent fiber, and GE was lower after consumption of the R diet compared with the other diets (P < 0.05).

CONCLUSIONS

Consumption of the R diet, but not RW or W diets, was associated with specific shifts in microbial community composition and function, but also with lower ATTD.

What Is the Microbiota and What Is Its Role in Colic?

The fecal microbiome of the horse is reflective of the large colon and plays an important role in the health of the horse. The microbes of the gastrointestinal tract digest fiber and produce energy for the host. Healthy horses have Firmicutes, Bacteroidetes, and Verrucromicrobia as the most common phyla. During gastrointestinal disease such as colic or colitis, the microbiome shows less diversity and changes in bacterial community composition.

Diet Influences the Gut Microbial Diversity and Olfactory Preference of the German Cockroach Blattella germanica

The gut microbiota of insects has been proven to play a role in the host's nutrition and foraging. The German cockroach, Blattella germanica, is an important vector of various pathogens and causes severe allergic reactions in humans. Food bait is an effective and frequently used method of controlling this omnivorous insect. Thus, understanding the relationships among diet, gut microbiota, and olfactory preferences could be useful for optimizing this management strategy. In this study, B. germanica was exposed to different foods, i.e., high-fat diet, high-protein diet, high-starch diet, and dog food (as control). Then their gut microbial and olfactory responses were investigated. 16S rRNA gene sequencing confirmed that the gut microbiota significantly differed across the four treatments, especially in relation to bacteria associated with the metabolism and digestion of essential components. Behavioral tests and the antenna electrophysiological responses showed that insects had a greater preference for other types of diets compared with their long-term domesticated diet. Moreover, continuously providing a single-type diet could change almost all the OR genes' expression of B. germanica, especially BgORco, which was significantly repressed compared to control. These results indicate that diet can shape the gut microbiota diversity and drive the olfactory preference of B. germanica. The association between gut microbiota profiles and diets can be utilized in managing B. germanica according to their olfactory preference.

Longitudinal fecal microbiome and metabolite data demonstrate rapid shifts and subsequent stabilization after an abrupt dietary change in healthy adult dogs

Background

Diet has a large influence on gut microbiota diversity and function. Although previous studies have investigated the effect of dietary interventions on the gut microbiome, longitudinal changes in the gut microbiome, microbial functions, and metabolite profiles post dietary interventions have been underexplored. How long these outcomes require to reach a steady-state, how they relate to one another, and their impact on host physiological changes are largely unknown. To address these unknowns, we collected longitudinal fecal samples following an abrupt dietary change in healthy adult beagles (n = 12, age: 5.16 ± 0.87 year, BW: 13.37 ± 0.68 kg) using a crossover design. All dogs were fed a kibble diet (control) from d1-14, and then fed that same diet supplemented with fiber (HFD) or a protein-rich canned diet (CD) from d15-27. Fresh fecal samples were collected on d13, 16, 20, 24, and 27 for metabolite and microbiome assessment. Fecal microbial diversity and composition, metabolite profiles, and microbial functions dramatically diverged and stabilized within a few days (2 d for metabolites; 6 d for microbiota) after dietary interventions. Fecal acetate, propionate, and total short-chain fatty acids increased after change to HFD, while fecal isobutyrate, isovalerate, total branched-chain fatty acids, phenol, and indole increased after dogs consumed CD. Relative abundance of ~ 100 bacterial species mainly belonging to the Firmicutes, Proteobacteria, and Actinobacteria phyla increased in HFD. These shifts in gut microbiome diversity and composition were accompanied by functional changes. Transition to HFD led to increases in the relative abundance of KEGG orthology (KO) terms related to starch and sucrose metabolism, fatty acid biosynthesis, and amino sugar and nucleotide sugar metabolism, while transition to CD resulted in increased relative abundance of KO terms pertaining to inositol phosphate metabolism and sulfur metabolism. Significant associations among fecal microbial taxa, KO terms, and metabolites were observed, allowing for high-accuracy prediction of diet group by random forest analysis.

Conclusions

Longitudinal sampling and a multi-modal approach to characterizing the gastrointestinal environment allowed us to demonstrate how drastically and quickly dietary changes impact the fecal microbiome and metabolite profiles of dogs following an abrupt dietary change and identify key microbe-metabolite relationships that allowed for treatment prediction.

Impact of Dietary Sodium Butyrate and Salinomycin on Performance and Intestinal Microbiota in a Broiler Gut Leakage Model

Unfavorable alterations of the commensal gut microbiota and dysbacteriosis is a major health problem in the poultry industry. Understanding how dietary intervention alters the microbial ecology of broiler chickens is important for prevention strategies. A trial was conducted with 672 Ross 308 day-old male broilers fed a basic diet (no additives, control) or the basic diet supplemented with 500 mg/kg encapsulated butyrate or 68 mg/kg salinomycin. Enteric challenge was induced by inclusion of 50 g/kg rye in a grower diet and oral gavage of a 10 times overdose of a vaccine against coccidiosis. Compared to control and butyrate-supplemented birds, salinomycin supplementation alleviated growth depression. Compared to butyrate and non-supplemented control, salinomycin increased potentially beneficial Ruminococcaceae and reduced potentially pathogenic Enterobacteriaceae and counts of Lactobacillus salivarius and Clostridium perfringens. Further, salinomycin supplementation was accompanied by a pH decrease and succinic acid increase in ceca, while coated butyrate (0.5 g/kg) showed no or limited effects. Salinomycin alleviated growth depression and maintained intestinal homeostasis in the challenged broilers, while butyrate in the tested concentration showed limited effects. Thus, further investigations are required to identify optimal dietary inclusion rates for butyrate used as alternative to ionophore coccidiostats in broiler production.

Effect of Geography and Captivity on Scat Bacterial Communities in the Imperiled Channel Island Fox

With developing understanding that host-associated microbiota play significant roles in individual health and fitness, taking an interdisciplinary approach combining microbiome research with conservation science is increasingly favored. Here we establish the scat microbiome of the imperiled Channel Island fox (Urocyon littoralis) and examine the effects of geography and captivity on the variation in bacterial communities. Using high throughput 16S rRNA gene amplicon sequencing, we discovered distinct bacterial communities in each island fox subspecies. Weight, timing of the sample collection, and sex contributed to the geographic patterns. We uncovered significant taxonomic differences and an overall decrease in bacterial diversity in captive versus wild foxes. Understanding the drivers of microbial variation in this system provides a valuable lens through which to evaluate the health and conservation of these genetically depauperate foxes. The island-specific bacterial community baselines established in this study can make monitoring island fox health easier and understanding the implications of inter-island translocation clearer. The decrease in bacterial diversity within captive foxes could lead to losses in the functional services normally provided by commensal microbes and suggests that zoos and captive breeding programs would benefit from maintaining microbial diversity.

Low Crude Protein Diet Affects the Intestinal Microbiome and Metabolome Differently in Barrows and Gilts

Low protein diets are commonly used in the growing-finishing pig stage of swine production; however, the effects of low dietary protein on the intestinal microbiota and their metabolites, and their association with pig sex, remain unclear. The present study aimed to assess the impact of a low crude protein (CP) diet on the gut microbiome and metabolome, and to reveal any relationship with sex. Barrows and gilts (both n = 24; initial body = 68.33 ± 0.881 kg) were allocated into two treatments according to sex. The four groups comprised two pairs of gilts and barrows fed with a high protein diet (CP 17% at stage I; CP 13% at stage II) and a low protein diet (CP 15% at stage I; CP 11% at stage II), respectively, for 51 d. Eight pigs in each group were slaughtered and their colon contents were collected. Intestinal microbiota and their metabolites were assessed using 16S rRNA sequencing and tandem mass spectrometry, respectively. The low protein diet increased intestinal microbiota species and richness indices (P < 0.05) in both sexes compared with the high protein diet. The sample Shannon index was different (P < 0.01) between barrows and gilts. At the genus level, unidentified Clostridiales (P < 0.05), Neisseria (P < 0.05), unidentified Prevotellaceae (P < 0.01) and Gracilibacteria (P < 0.05) were affected by dietary protein levels. The relative abundance of unidentified Prevotellaceae was different (P < 0.01) between barrows and gilts. The influence of dietary protein levels on Neisseria (P < 0.05), unidentified Prevotellaceae (P < 0.01) and Gracilibacteria (P < 0.05) were associated with sex. Metabolomic profiling indicated that dietary protein levels mainly affected intestinal metabolites in gilts rather than barrows. A total of 434 differentially abundant metabolites were identified in gilts fed the two protein diets. Correlation analysis identified that six differentially abundant microbiota communities were closely associated with twelve metabolites that were enriched for amino acids, inflammation, immune, and disease-related metabolic pathways. These results suggested that decreasing dietary protein contents changed the intestinal microbiota in growing-finishing pigs, which selectively affected the intestinal metabolite profiles in gilts.

Unveiling the Fecal Microbiota in Two Captive Mexican Wolf (Canis lupus baileyi) Populations Receiving Different Type of Diets

Simple Summary

The Mexican wolf (Canis lupus baileyi) is an endangered canine. Both Mexico and the United States are currently collaborating to reproduce and reintroduce individuals to their original habitats. However, keeping these wolves in captivity represents a great commitment to meet their basic needs. Diet is a determining factor that is closely related to health and reproductive fitness. The type of diet that is fed to canines in captivity must provide the required nutrients for their development and welfare. The study of the fecal microbiota is a non-invasive way to establish the abundance and diversity of bacterial communities to determine if they are in a healthy condition. We analyzed data from two captive populations of Mexican wolves (i.e., northern and central Mexico) receiving different type of diets (Michilia population: mainly kibble vs. Ocotal population: mainly raw meat). The operational taxonomic units (OTUs) in Michilia resulted in 204 genera and 316 species, while in Ocotal there were 232 genera and 379 species. In the Michilia, dominance of bacteria that degrade carbohydrates was observed (related to kibble diet). In contrast, the Ocotal microbiota was dominated by protein-degrading bacteria (related to raw meat diet). The main outcomes generated in this study should help to enhance the welfare of the captive Mexican wolves to increase its numbers.

Abstract

The Mexican wolf (Canis lupus baileyi) was once distributed in southern United States and northern Mexico. It is an endangered subspecies detached from the gray wolf, and likely exemplifies one of the original migration waves of C. lupus into the new world. This is a canine whose individuals survive in specialized facilities, zoos, and museums as part of captive-breeding programs. In order to contribute to the improvement of the management of this species and favor its long-term conservation in Mexico, we aimed to evaluate the diversity and abundance of the fecal bacterial microbiota in two populations exposed to different types of diet: (1) Michilia (23° N, 104° W); kibble daily and raw meat sporadically, and (2) Ocotal (19° N, 99° W); raw meat daily and live animals periodically. Next generation sequencing (V3-V4 16S rRNA gene) by Illumina was implemented. The operational taxonomic units (OTUs) in Michilia resulted in 9 phyla, 19 classes, 34 orders, 61 families, 204 genera, and 316 species, while in Ocotal there were 12 phyla, 24 classes, 37 orders, 69 families, 232 genera, and 379 species. Higher estimated Chao1 richness, Shannon diversity, and core microbiota were observed in Ocotal. Differences (p < 0.05) between populations occurred according to the Bray–Curtis beta diversity index. In the Michilia, dominance of bacteria that degrade carbohydrates (Firmicutes, Lachnospiraceae, Blautia, Clostrodium, Eisenbergiella, Romboutsia, and Ruminococcus) was observed; they are abundant in kibble diets. In contrast, the Ocotal microbiota was dominated by protein-degrading bacteria (Fusobacteria, Fusobacteriaceae, and Fusobacteria), indicating a possible positive relation with a raw meat diet. The information generated in this study is fundamental to support the implementation of better management plans in the two populations considered here, as well as in different facilities of southern United States and Mexico, where this subspecies is kept in captivity for conservation purposes.

Modified Black Soldier Fly Larva Fat in Broiler Diet: Effects on Performance, Carcass Traits, Blood Parameters, Histomorphological Features and Gut Microbiota

Simple Summary

Black soldier fly (Hermetia illucens L.; BSF) is gaining interest as a functional feed additive, due to the high amount of medium-chain fatty acids (MCFAs) and monoglycerides, which provide antimicrobial activities and stimulate gastrointestinal health through inhibition of potentially pathogenic bacteria. The present study evaluated the effect of BSF and modified BSF larvae fat in broiler chicken’s diet. Overall results were comparable among the studied diets, suggesting that modified BSF larvae fat showed a positive modulation of fecal microbiota by a positive reduction in potentially pathogenic bacteria such as Clostridium and Corynebacterium, without affecting intestinal morphology or showing any adverse histopathological alternations.

Abstract

In this study, a total of 200 male broiler chickens (Ross 308) were assigned to four dietary treatments (5 pens/treatment and 10 birds/pen) for two feeding phases: starter (0–11 days of age) and grower-finisher (11–33 days of age). A basal diet containing soy oil (SO) as added fat was used as control group (C), tested against three experimental diets where the SO was partially substituted by BSF larvae fat (BSF) or one of two types of modified BSF larvae fat (MBSF1 and MBSF2, respectively). The two modified BSF larvae fats had a high and low ratio of monobutyrin to monoglycerides of medium chain fatty acid, respectively. Diet did not influence the growth or slaughter performance, pH, color, or the chemical composition of breast and thigh muscles, gut morphometric indices, or histopathological alterations in all the organs. As far as fecal microbiota are concerned, MBSF1 and MBSF2 diets reduced the presence of Clostridium and Corynebacterium, which can frequently cause infection in poultry. In conclusion, modified BSF larva fat may positively modulate the fecal microbiota of broiler chickens without influencing the growth performance and intestinal morphology or showing any adverse histopathological alternations.

Effect of sequentially fed high protein, hydrolyzed protein, and high fiber diets on the fecal microbiota of healthy dogs: a cross-over study

Background

Dietary content and environmental factors can shape the gut microbiota, and consequently, the way the gut microbiota metabolizes fats, carbohydrates, and proteins, affecting overall health of the host. We evaluated the impact of 3 diets (all meat [raw], high-insoluble fiber dry extruded diet and hydrolyzed protein dry extruded diet) on the gut microbiota of healthy dogs in a cross-over sequential study.

Results

We showed that diet can have an effect on the gut microbiome in dogs, which was influenced by the order of feeding. High-protein (all meat) diets were characterized by an increase in bacteria belonging to the Fusobacteria and Bacteroidetes phyla, whereas a high-insoluble fiber commercial diet correlated with increases in Firmicutes and Actinobacteria phyla. However, the individual dog’s baseline microbiota had the most impact on the magnitude and nature of the changes in response to dietary intervention.

Conclusion

Our results suggest that the dog fecal microbiota is driven by protein and fiber composition to different degrees in individual animals, and targeted modification of these patterns could be useful in the modulation of the gut microbiota in different diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-021-00101-8.

Use of Legumes and Yeast as Novel Dietary Protein Sources in Extruded Canine Diets

The popularity of plant-based protein sources has increased as consumer demand for grain-free and novel protein sources increase. Minimal research has been conducted as regards to use of legumes and yeast and their effects on acceptability and digestibility in canine diets. The objective of this study was to evaluate macronutrient apparent total tract digestibility (ATTD), gastrointestinal tolerance, and fermentative end-products in extruded, canine diets. Five diets were formulated to be isocaloric and isonitrogenous with either garbanzo beans (GBD), green lentils (GLD), peanut flour (PFD), dried yeast (DYD), or poultry by-product meal (CON) as the primary protein sources. Ten adult, intact, female beagles (mean age: 4.2 ± 1.1 yr, mean weight: 11.9 ± 1.3 kg) were used in a replicated, 5 × 5 Latin square design with 14 d periods. Each experimental period consisted of 10 d of diet adaptation, followed by 4 d of total fecal and urine collection. A fasted, 5 ml blood sample was collected at the end of each period and analyzed for serum metabolites and complete blood count. Serum metabolites were within normal ranges and all dogs remained healthy throughout the study. Fecal quality, evaluated on a 5-point scale, was considered ideal. Macronutrient ATTD was similar among dietary treatments, with diets highly digestible (>80%). Total fecal branched-chain fatty acid concentrations were highest (P < 0.05) for DYD (23.4 μmol/g) than GLD (16.1 μmol/g) and PFD (16.0 μmol/g) but not different (P > 0.05) than other treatments. The plant-based protein treatments had greater (P < 0.05) total fecal short chain fatty acid (SCFA) concentrations (average 627.6 μmol/g) compared with CON (381.1 μmol/g). Fecal butyrate concentration was highest (P < 0.05) for DYD than all other dietary treatments (103.9 μmol/g vs. average 46.2 μmol/g). Fecal microbial communities showed Firmicutes, Bacteroidetes, Fusobacteria, and Proteobacteria as abundant phyla. There was greater β-diversity for dogs fed DYD which differed from all other diets in both weighted and unweighted UNIFRAC analyses. Inclusion of these novel, plant-based, protein sources showed no detrimental effects on nutrient digestibility or fecal characteristics and represent viable protein sources in canine diets that can produce beneficial shifts in fecal metabolites.

White and Red Sorghum as Primary Carbohydrate Sources in Extruded Diets of Felines

The research objectives were to evaluate the effect of dietary supplementation of white (WSH) and red (RSH) sorghum grains on gastrointestinal health of felines through the determination of apparent total tract macronutrient digestibility (ATTD), fecal characteristics, fermentative end-products, and microbiota, compared with a traditional corn-based diet. We hypothesize that inclusion of RSH and WSH, respectively, would be well-accepted by cats, and the RSH and WSH diets would be comparable to corn when added as the main carbohydrate source in extruded diets. Three diets containing 30% corn, 30% WSH, or 30% RSH were formulated to meet or exceed the AAFCO (2018) nutrient profiles for cats during growth. Nine male cats (0.8 ± 0.00 yr) were randomly assigned to one of the three dietary treatments using a triplicated 3 × 3 Latin square design. Experimental periods consisted of 14 d (10 d of diet adaption and 4 d of total and fresh fecal collections). The ATTD of dry matter (DM) did not differ amongst treatments, organic matter was greatest (P < 0.05) for both sorghum diets (86.4%) and lowest for the corn diet (84.2%), crude protein was comparable among diets ranging from 84.5 to 86.6%, acid hydrolyzed fat was high among diets varying between 91.4 and 92.8%, and total dietary fiber was greatest (P < 0.05) for the WSH diet (56.0%) with the corn diet being lowest (44.7%). Digestible energy was greatest (P < 0.05) for the WSH diet (4.66 kcal/g) and lowest for the corn diet (4.54 kcal/g), with the RSH diet being intermediate (4.64; P > 0.05). Fecal pH (6.3–6.5) and most fecal metabolites did not differ among diets except for phenol/indole concentrations that were significantly lower (P < 0.05) in cats fed the RSH diet (1.5 μmole/g DM) than for cats fed the corn diet (2.1 μmole/g DM). Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria were the major phyla observed in the microbiota of feces of cats fed the three experimental diets, with no differences seen amongst all treatments. Data indicate that dietary supplementation of these varieties of WSH and RSH as carbohydrate sources were well-tolerated by the cat.

Flexibility and resilience of great tit (Parus major) gut microbiomes to changing diets

Background

Gut microbial communities play important roles in nutrient management and can change in response to host diets. The extent of this flexibility and the concomitant resilience is largely unknown in wild animals. To untangle the dynamics of avian-gut microbiome symbiosis associated with diet changes, we exposed Parus major (Great tits) fed with a standard diet (seeds and mealworms) to either a mixed (seeds, mealworms and fruits), a seed, or a mealworm diet for 4 weeks, and examined the flexibility of gut microbiomes to these compositionally different diets. To assess microbiome resilience (recovery potential), all individuals were subsequently reversed to a standard diet for another 4 weeks. Cloacal microbiomes were collected weekly and characterised through sequencing the v4 region of the 16S rRNA gene using Illumina MiSeq.

Results

Initial microbiomes changed significantly with the diet manipulation, but the communities did not differ significantly between the three diet groups (mixed, seed and mealworm), despite multiple diet-specific changes in certain bacterial genera. Reverting birds to the standard diet led only to a partial recovery in gut community compositions. The majority of the bacterial taxa that increased significantly during diet manipulation decreased in relative abundance after reversion to the standard diet; however, bacterial taxa that decreased during the manipulation rarely increased after diet reversal

Conclusions

The gut microbial response and partial resilience to dietary changes support that gut bacterial communities of P. major play a role in accommodating dietary changes experienced by wild avian hosts. This may be a contributing factor to the relaxed association between microbiome composition and the bird phylogeny. Our findings further imply that interpretations of wild bird gut microbiome analyses from single-time point sampling, especially for omnivorous species or species with seasonally changing diets, should be done with caution. The partial community recovery implies that ecologically relevant diet changes (e.g., seasonality and migration) open up gut niches that may be filled by previously abundant microbes or replaced by different symbiont lineages, which has important implications for the integrity and specificity of long-term avian-symbiont associations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-021-00076-6.

Paternal Methyl Donor Supplementation in Rats Improves Fertility, Physiological Outcomes, Gut Microbial Signatures and Epigenetic Markers Altered by High Fat/High Sucrose Diet

Increased consumption of high fat/sucrose (HF/S) diets has contributed to rising rates of obesity and its co-morbidities globally, while also negatively impacting male reproductive health. Our objective was to examine whether adding a methyl donor cocktail to paternal HF/S diet (HF/S+M) improves health status in fathers and offspring. From 3–12 weeks of age, male Sprague Dawley rats consumed a HF/S or HF/S+M diet. Offspring were followed until 16 weeks of age. Body composition, metabolic markers, gut microbiota, DNA methyltransferase (DNMT) and microRNA expression were measured in fathers and offspring. Compared to HF/S, paternal HF/S+M diet reduced fat mass in offspring (p < 0.005). HF/S+M fathers consumed 16% fewer kcal/day, which persisted in HF/S+M female offspring and was explained in part by changes in serum glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) levels. Compared to HF/S, HF/S+M fathers had a 33% improvement in days until conception and 300% fewer stillbirths. In fathers, adipose tissue DNMT3a and hepatic miR-34a expression were reduced with HF/S+M. Adult male offspring showed upregulated miR-24, -33, -122a and -143 expression while females exhibited downregulated miR-33 expression. Fathers and offspring presented differences in gut microbial signatures. Supplementing a paternal HF/S diet with methyl-donors improved fertility, physiological outcomes, epigenetic and gut microbial signatures intergenerationally.

High-Fat Diets Led to OTU-Level Shifts in Fecal Samples of Healthy Adult Dogs

High fat diets have been reported to negatively affect the microbiota in both mice and humans. However, there is a lack of studies in canine models. The variation among the gastrointestinal (GI) tract anatomy/physiology and typical diet compositions of these animal species may lead to vastly different results. Due to the large inclusion rate of dietary fat in pet food, it is critical to understand its effects in a canine model. Therefore, the study objective was to report the effects of high fat, low carbohydrate diets on the fecal microbiota in healthy adult dogs. Eight adult beagles were randomly assigned to one of four dietary treatments within each 15-day period of a replicated 4x4 Latin Square design. Diets contained 32% (T1), 37% (T2), 42% (T3), and 47% (T4) fat. T2, T3, and T4 were created by adding increasing levels of canola oil to T1, a commercially manufactured canned canine diet, which served as the control diet. Fresh fecal samples were collected during the last 5 days of each period for microbial analysis. DNA was extracted from fecal samples and paired-end 16S rRNA gene amplicon sequencing was performed using the Illumina MiSeq platform. When comparing whole microbial communities using PERMANOVA, no significant differences were observed among treatments (P = 0.735). Individual OTUs were analyzed using the GLIMMIX procedure of SAS with fixed effects of diet and room, and the random effects of period and animal. Out of the 100 most abundant individual OTUs, 36 showed significant differences in abundance based on treatment (q < 0.05). Overall, OTUs assigned to genera related to fat digestion increased while OTUs assigned to genera involved in carbohydrate digestion decreased. In conclusion, the microbial community adapted to dietary intervention without jeopardizing the health of the animals, evaluated by body condition score, fecal characteristics, and blood parameters.

Gut Microbiomes Differ Among Dietary Types and Stool Consistency in the Captive Red Wolf (Canis rufus)

Captive management of many wildlife species can be challenging, with individuals displaying health disorders that are not generally described in the wild population. Retrospective studies have identified gastrointestinal (GI) diseases, in particular inflammatory bowel disease (IBD), as the second leading cause of captive adult red wolf (Canis rufus) mortality. Recent molecular studies show that imbalanced gut microbial composition is tightly linked to IBD in the domestic dog. The goal of the present study was to address two main questions: (1) how do red wolf gut microbiomes differ between animals with loose stool consistency, indicative of GI issues, and those with normal stool consistency and (2) how does dietary type relate to stool consistency and red wolf gut microbiomes? Fresh fecal samples were collected from 48 captive wolves housed in eight facilities in the United States and from two wild wolves living in Alligator River National Wildlife Refuge, NC, United States. For each individual, the stool consistency was categorized as loose or normal using a standardized protocol and their diet was categorized as either wild, whole meat, a mix of whole meat and kibble or kibble. We characterized gut microbiome structure using 16S rRNA gene amplicon sequencing. We found that red wolves with a loose stool consistency differed in composition than wolves with normal stool consistency, suggesting a link between GI health and microbiome composition. Diet was not related to stool consistency but did significantly impact gut microbiome composition; gut microbiome composition of wolves fed a kibble diet were significantly different than the gut microbiome composition of wolves fed a mixed, whole meat and wild diet. Findings from this study increase the understanding of the interplay between diet and GI health in the red wolf, a critical piece of information needed to maintain a healthy red wolf population ex situ.

Targeted Metabolomics With Ultraperformance Liquid Chromatography-Mass Spectrometry (UPLC-MS) Highlights Metabolic Differences in Healthy and Atopic Staffordshire Bull Terriers Fed Two Different Diets, A Pilot Study

Background: While anecdotal evidence has long claimed that a raw meat-based diet (RMBD) improves the metabolic health of canines, no rigorous scientific study has clarified this issue. Canine atopic dermatitis (CAD) has also been linked to metabolic health, but its relation to diet remains poorly understood. This study investigates whether dietary choice is linked to metabolic health in healthy and CAD-diagnosed canines via targeted serum and urine metabolomic analysis of polar, non-ionic metabolites, as well as whether the underlying CAD condition modulates the response to nutritional intake. Materials and Methods: Serum metabolites of client-owned Staffordshire bull terriers, divided into CAD-diagnosed (n = 14) and healthy (n = 6) cohorts, were studied. Urine metabolites of a subset of the CAD-diagnosed canines (n = 8) were also studied. The canines were split into two cohorts based on diet. The first cohort were fed a commercially available high-fat, moderate-protein, low-carbohydrate RMBD (n = 11, CAD diagnosed n = 8, healthy n = 3). Those in the second cohort were fed a commercially available moderate-fat, moderate-protein, high-carbohydrate kibble diet (KD) (n = 9: CAD diagnosed n = 6, healthy n = 3). The diet intervention period lasted approximately 4.5 months (median 135 days). Statistical analyses of the serum profiles across all dogs (n = 20) and the urine profiles of the CAD-diagnosed subset (n = 8) were performed. Results and Discussion: The KD cohort was found to have higher concentrations of methionine than the RMBD cohort, both in serum (all dogs, p < 0.0001) and in urine (CAD-only cohort, p < 0.0002), as well as cystathionine and 4-pyridoxic acid. Methionine plays important roles in homocysteine metabolism, and elevated levels have been implicated in various pathologies. The CAD (n = 14) cohort dogs showed starker metabolic changes in response to diet regarding these pathways compared to the healthy (n = 6) cohort. However, there was no significant change in CAD severity as a result of either diet. Likely due to the higher meat content of the RMBD, higher concentrations of several carnitines and creatine were found in the RMBD cohort. Citrulline was found in higher concentrations in the KD cohort. Our findings provide insight into the relationship between diet and the serum and urine metabolite profiles of canines. They also suggest that neither diet significantly affected CAD severity.

Varying Protein Levels Influence Metabolomics and the Gut Microbiome in Healthy Adult Dogs

The optimal ranges of protein for healthy adult dogs are not known. This study evaluated the impact of long-term consumption of foods containing low, medium, and high levels of protein on serum, urine, and fecal metabolites, and gut microbiome in beagles. Following maintenance on a prefeed food for 14 days, dogs (15 neutered males, 15 spayed females, aged 2–9 years, mean initial weight 11.3 kg) consumed the low (18.99%, dry matter basis), medium (25.34%), or high (45.77%) protein foods, each for 90 days, in a William’s Latin Square Design sequence. In serum and/or urine, metabolites associated with inflammation (9,10-dihydroxyoctadecanoic acid (DiHOME)), 12,13-DiHOME) and kidney dysfunction (urea, 5-hydroxyindole sulfate, 7-hydroxyindole sulfate, p-cresol sulfate) increased with higher protein levels in food, while one-carbon pathway metabolites (betaine, dimethylglycine, sarcosine) decreased. Fecal pH increased with protein consumed, and levels of beneficial indoles and short-chain fatty acids decreased while branched-chain fatty acids increased. Beta diversity of the fecal microbiome was significantly different, with increased abundances of proteolytic bacteria with higher protein food. Feeding dogs a high amount of protein leads to a shift to proteolytic gut bacteria, higher fecal pH, and is associated with increased levels of metabolites linked with inflammation and kidney dysfunction.

Distribution of microbiota across different intestinal tract segments of a stranded dwarf minke whale, Balaenoptera acutorostrata

Marine mammals are an important part of ocean ecosystems, of which, whales play a vital role in the marine food chain. In this study, the mucosa and contents from different intestinal tract segments (ITSs) of a stranded dwarf minke whale (Balaenoptera acutorostrata) were analyzed. The gut microbiota were sequenced using high‐throughput sequencing technology, based on a 16S rRNA approach. The microbial composition of the intestinal mucosa and its contents were similar in every single ITS. Large intestine microbiota richness and diversity were significantly higher when compared to the duodenum and jejunum. The dominant bacteria in the gut were Firmicutes and Actinobacteria; the former was enriched in the large intestine, whereas the latter was more abundant in the duodenum and jejunum. Our findings provide novel insights for microbiota in B. acutorostrata.

Modulation of the intestinal microbiota of broilers supplemented with monensin or functional oils in response to challenge by Eimeria spp

The objective of this study was to evaluate the effect of supplementation with 100ppm sodium monensin or 0.15% of a blend of functional oils (cashew nut oil + castor oil) on the intestinal microbiota of broilers challenged with three different Eimeria spp. The challenge was accomplished by inoculating broiler chicks with sporulated oocysts of Eimeria tenella, Eimeria acervulina, and Eimeria maxima via oral gavage. A total of 864, day-old male broiler chicks (Cobb) were randomly assigned to six treatments (eight pens/treatment; 18 broilers/pen) in a 3 × 2 factorial arrangement, composed of three additives (control, monensin or blend), with or without Eimeria challenge. Intestinal contents was collected at 28 days of age for microbiota analysis by sequencing 16s rRNA in V3 and V4 regions using the Illumina MiSeq platform. Taxonomy was assigned through the SILVA database version 132, using the QIIME 2 software version 2019.1. No treatment effects (p > 0.05) were observed in the microbial richness at the family level estimated by Chao1 and the biodiversity assessed by Simpson’s index, except for Shannon's index (p < 0.05). The intestinal microbiota was dominated by members of the order Clostridiales and Lactobacillales, followed by the families Ruminococcaceae, Bacteroidaceae, and Lactobacillaceae, regardless of treatment. When the controls were compared, in the challenged control group there was an increase in Erysipelotrichaceae, Lactobacillaceae, Bacteroidaceae, Streptococcaceae, and Peptostreptococcaceae, and a decrease in Ruminococcaceae. Similar results were found for a challenged group that received monensin, while the blend partially mitigated this variation. Therefore, the blend alleviated the impact of coccidiosis challenge on the microbiome of broilers compared to monensin.

The canine gastrointestinal microbiota: early studies and research frontiers

The canine gut microbiota is a complex microbial population that is potentially related to metabolism, immunologic activity and gastrointestinal (GI) diseases. Early studies revealed that the canine gut microbiota was dynamic, and bacterial populations in the adjacent gut segments were similar, with anaerobes predominating. Metagenomics analysis revealed that nutrient contents in the diet modulated bacterial populations and metabolites in the canine gut. Further research revealed significant correlations between dietary factors and canine gut core microbiomes. Canine GI diseases are closely correlated with gut microbiota dysbiosis and metabolic disorders. Probiotic-related therapies can effectively treat canine GI diseases. Recent studies have revealed that the canine gut microbiota is similar to the human gut microbiota, and dietary factors affect both. Studying canine intestinal microorganisms enables clarifying changes in the canine intestinal bacteria under different conditions, simulating human diseases in dog models, and conducting in-depth studies of the interactions between intestinal bacteria and disease.

Combination of Bacillus licheniformis and Salinomycin: Effect on the Growth Performance and GIT Microbial Populations of Broiler Chickens

Simple Summary

The beneficial effects of Bacillus spp. probiotic preparations used for poultry are well-documented and characterized by growth performance improvement and positive modulation of gastrointestinal tract (GIT) microbiota. Moreover, the favorable influence of salinomycin has been frequently studied as an ionophore coccidiostat, as well as an antimicrobial agent. However, limited data are available in terms of the parallel usage of both Bacillus licheniformis DSM 28710 and salinomycin in poultry diets. From a practical point of view, evaluating the potential interactions between this species and agent is crucial to assess their parallel usage, and the current study confirmed the positive effect of their mixture on the modulation of pH value in the crop and ceca, as well as the GIT microbiota, especially in the jejunum and ceca. Additionally, the results obtained in this study show positive effects of B. licheniformis on the growth performance, as well as the influence of both experimental factors used separately in the case of GIT microbiota modulations.

Abstract

The aim of the study was to investigate the effect of Bacillus licheniformis and salinomycin supplementation in broiler diets as individual factors or in combination on the growth performance, GIT morphometry, and microbiota populations. Four hundred one-day-old Ross 308 chicks were randomly distributed to four dietary treatments (10 replicates, 10 birds each). The following treatments were applied: NC—no additives; NC + SAL—salinomycin addition (60 mg/kg diet), NC + PRO—B. licheniformis DSM 28710 preparation (1.6 × 10⁹ CFU/kg; 500 mg/kg diet), and NC + SAL + PRO—combination of salinomycin and B. licheniformis. Probiotic administration resulted in improvement (p < 0.05) of the performance parameters, including body weight gain (1–10 d, and 11–22 d) and feed conversion ratio (11–22 d, 1–36 d). An interaction (p < 0.05) between experimental factors was observed in terms of lower pH values in the crop (tendency, p = 0.053) and ceca. Both factors lowered the alpha diversity and Enterobacteriaceae and promoted Bacillaceae communities in the jejunum (p < 0.05). Interactions were also observed in terms of reducing Clostridiaceae in the ceca. In conclusion, the combined use of B. licheniformis and salinomycin in broilers’ diets had beneficial effects.

Characterization of gut microbiomes of household pets in the United States using a direct-to-consumer approach

The role of gut microbiomes as important regulators of mammalian health is increasingly recognized, although feline and canine gut microbiomes remain poorly characterized. In this proof-of-concept study, we assessed the utility of a direct-to-consumer approach to executing pet microbiome studies. We characterized the gut microbiomes of 238 pets (46 cats and 192 dogs) by generating ~11 million merged reads that were mapped to the V4 region of 16S ribosomal RNA gene at a sequencing depth of 45,806 (±22,325) reads per sample. Analyses of these reads revealed that both feline and canine gut microbiomes are dominated by three major phyla, namely Firmicutes, Proteobacteria, and Bacteroides and that alpha diversity is higher in the feline gut. In addition to interspecies differences between the feline and canine gut, we also detected appreciable intraspecies bacterial variation within the canine population. While the dogs in this dataset could be assigned to three distinct clusters based on their gut microbiome, no clustering was observed within the feline population. Integration of additional data obtained from survey questionnaires revealed that geography and body weight may be associated with canine gut microbiome composition. Furthermore, we found that both the inter and intraspecies differences are more pronounced at finer taxonomic levels, indicating that strain-level investigations may be necessary in the future. This study demonstrates that the direct-to-consumer approach overcomes existing limitations in pet microbiome research, for example, it allows collection of large numbers of pet samples. The direct-to-consumer approach has proven successful in human genomics as well as human microbiomics and this study demonstrates that by building partnerships with an engaged general public this approach can also propel the field of pet microbiomics forward.

Role of Dietary Nutrients in the Modulation of Gut Microbiota: A Narrative Review

Understanding how dietary nutrients modulate the gut microbiome is of great interest for the development of food products and eating patterns for combatting the global burden of non-communicable diseases. In this narrative review we assess scientific studies published from 2005 to 2019 that evaluated the effect of micro- and macro-nutrients on the composition of the gut microbiome using in vitro and in vivo models, and human clinical trials. The clinical evidence for micronutrients is less clear and generally lacking. However, preclinical evidence suggests that red wine- and tea-derived polyphenols and vitamin D can modulate potentially beneficial bacteria. Current research shows consistent clinical evidence that dietary fibers, including arabinoxylans, galacto-oligosaccharides, inulin, and oligofructose, promote a range of beneficial bacteria and suppress potentially detrimental species. The preclinical evidence suggests that both the quantity and type of fat modulate both beneficial and potentially detrimental microbes, as well as the Firmicutes/Bacteroides ratio in the gut. Clinical and preclinical studies suggest that the type and amount of proteins in the diet has substantial and differential effects on the gut microbiota. Further clinical investigation of the effect of micronutrients and macronutrients on the microbiome and metabolome is warranted, along with understanding how this influences host health.

Bacillus licheniformis-fermented products improve growth performance and the fecal microbiota community in broilers

This study investigated the effects of Bacillus licheniformis–fermented products on the growth performance and fecal microbial community of broilers. A total of 144 one-day-old male broiler chicks (Ross 308) were randomly assigned into 4 dietary treatments, with 6 replicate cages per treatment and 6 birds per cage. The dietary treatments comprised a basal diet as control, control plus 1 and 3 g/kg of B. licheniformis–fermented products, and control plus 10 mg/kg of enramycin. The results indicated that 3 g/kg of B. licheniformis–fermented products increased (P < 0.05) the BW and ADG of broilers relative to controls. No significant difference was observed in the growth performance of broilers fed enramycin and 3 g/kg of B. licheniformis–fermented products. However, principal coordinate analysis and a heatmap of species abundance indicated distinct clusters between the groups treated with enramycin and 3 g/kg of B. licheniformis–fermented products. The abundance of the phylum Firmicutes in feces increased (P < 0.05) in broilers fed 3 g/kg of B. licheniformis–fermented products, whereas the abundance of the phyla Verrucomicrobia and Bacteroidetes in feces decreased (P < 0.05) in response to treatment with 3 g/kg of B. licheniformis–fermented products. The abundance of the genera Enterococcus, Akkermansia, Ruminococcus torques group, Faecalibacterium, and Parabacteroides in feces decreased (P < 0.05) in broilers fed 3 g/kg of B. licheniformis–fermented products, whereas the abundance of the genus Lactobacillus in feces increased (P < 0.05) in response to treatment with 3 g/kg of B. licheniformis–fermented products. The average abundance of the genus Lactobacillus in feces was positively correlated with the growth performance of broilers. These results demonstrate that B. licheniformis–fermented products can improve the growth performance and fecal microflora composition of broilers.

Rifaximin prevents ethanol-induced liver injury in obese KK-Ay mice through modulation of small intestinal microbiota signature

Exacerbation of alcoholic hepatitis (AH) with comorbid metabolic syndrome is an emerging clinical problem, where microbiota plays a profound role in the pathogenesis. Here, we investigated the effect of rifaximin (RFX) on liver injury following chronic-binge ethanol (EtOH) administration in KK-A^y mice, a rodent model of metabolic syndrome. Female, 8-wk-old KK-A^y mice were fed Lieber-DeCarli diet (5% EtOH) for 10 days, following a single EtOH gavage (4 g/kg body wt). Some mice were given RFX (0.1 g/L, in liquid diet) orally. Small intestinal contents were collected from mice without binge. Intestinal microbiota was quantified using aerobic and anaerobic culturing techniques and further analyzed by 16S rRNA sequencing in detail. EtOH feeding/binge caused hepatic steatosis, oxidative stress, and induction of inflammatory cytokines in KK-A^y mice, which were markedly prevented by RFX treatment. Hepatic mRNA levels for cluster of differentiation 14, Toll-like receptor (TLR) 4, TLR2, and NADPH oxidase 2 were increased following EtOH feeding/binge, and administration of RFX completely suppressed their increase. The net amount of small intestinal bacteria was increased over threefold after chronic EtOH feeding as expected; however, RFX did not prevent this net increase. Intriguingly, the profile of small intestinal microbiota was dramatically changed following EtOH feeding in the order level, where the Erysipelotrichales predominated in the relative abundance. In sharp contrast, RFX drastically blunted the EtOH-induced increases in the Erysipelotrichales almost completely, with increased proportion of the Bacteroidales. In conclusion, RFX prevents AH through modulation of small intestinal microbiota/innate immune responses in obese KK-A^y mice.NEW & NOTEWORTHY Here we demonstrated that rifaximin (RFX) prevents chronic-binge ethanol (EtOH)-induced steatohepatitis in KK-A^y mice. Chronic EtOH feeding caused small intestinal bacterial overgrowth, with drastic alteration in the microbiota profile predominating the order Erysipelotrichales. RFX minimized this EtOH induction in Erysipelotrichales with substitutive increases in Bacteroidales. RFX also prevented EtOH-induced increases in portal lipopolysaccharide, and hepatic cluster of differentiation 14, toll-like receptor (TLR) 2, and TLR4 mRNA levels, suggesting the potential involvement of microbiota-related innate immune responses.

Comparison of the effects of four commercially available prescription diet regimens on the fecal microbiome in healthy dogs

The effects of prescription diets on canine intestinal microbiota are unknown. In this study, we used next generation sequencing to investigate the impact of four commercially available prescription diet regimens on the fecal microbiome in six healthy dogs. The diet regimens used were as follows: weight-loss diet, low-fat diet, renal diet, and anallergenic diet. We found a significantly decreased proportion of phylum Actinobacteria with the weight-loss diet compared to the anallergenic diet. There were no significant differences in the proportion of phylum Bacteroidetes between the four diets. The proportion of phylum Firmicutes was significantly decreased with the weight-loss diet compared to the anallergenic diet. The proportion of phylum Fusobacteria was significantly increased with the weight-loss diet compared to the anallergenic diet. There were no significant differences in the proportion of phylum Proteobacteria after consumption of the four diets. We therefore demonstrated that commercial prescription diet influences the fecal microbiome in healthy dogs. These results might be useful when choosing a prescription diet for targeting a disease.

PANCOSMA COMPARATIVE GUT PHYSIOLOGY SYMPOSIUM: ALL ABOUT APPETITE REGULATION: Effects of diet and gonadal steroids on appetite regulation and food intake of companion animals

The prominent incidence of overweight and obese pet animals not only results in higher morbidity and mortality, but also poses a threat for the quality of life, longevity, and well-being of dogs and cats. To date, strategies to prevent BW gain or to induce weight loss have had modest success in the pet population. In part, due to the complexity and the multifactorial nature of this disease, which involves pet-human interaction, environmental and dietary factors, and an intertwined metabolic process that still is not fully understood. As such, research methods to investigate the role of physiological hormones and dietary management on mechanisms related to the control of feelings of satiety and hunger in pet animals is warranted. Increasing interest exists in exploring gut chemosensing mechanisms, the crosstalk between metabolic-active tissues, and the interface between the gut microbiota and the nervous system (gut-brain axis). The noninvasive nature of research conducted in companion animals focuses on systemic approaches to develop environmental, nutritional, or therapeutic interventions that can be translated from research settings to pet-owned households. Because the majority of the pet population is spayed or neutered, it is important to determine the effect that sex hormones might have on appetite regulation and fasting metabolic rate of these animals. In general, studies have revealed that gonadectomy may establish a new "set point" characterized by increased food intake and BW, accompanied by physiological and behavioral changes. Some studies have also shown associations between gonadectomy and alterations in appetite-related hormones (e.g., ghrelin, leptin, adiponectin, glucagon-like peptide-1). Manipulation of macronutrients in diets of dogs and cats have also been investigated as a mean to improve satiety. Most of the research in this area has focused on high-protein diets, predominantly, for cats, and the use of dietary fiber sources of contrasting fermentability and viscosity profiles. Dietary fibers may affect the production of fermentative end products and gut microbiome, digestive and absorptive processes, appetite-related hormones, and promote "gut fill" and satiety. More recent studies have reported profound effects of dietary manipulation on the phylogeny and functional capacity of gut microbial communities of dogs and cats.

Balance of saccharolysis and proteolysis underpins improvements in stool quality induced by adding a fiber bundle containing bound polyphenols to either hydrolyzed meat or grain-rich foods

Dietary fiber is a key component in gastrointestinal health maintenance partly due to its fermentation by the gut microbiome. The food-dependent effects of a novel fiber bundle added to hydrolyzed meat (HM) or grain-rich (GR) foods in healthy dogs (n = 16) or those with chronic enteritis/gastroenteritis (n = 16) were examined. Addition of fiber to either food improved stool quality in dogs regardless of health status; microbiome diversity of dogs with chronic enteritis/gastroenteritis became more similar to healthy dogs. The abundance of bacteria mediating beneficial saccharolytic processes (eg, Lachnospiraceae) significantly increased on addition of fiber to the GR food, while those mediating detrimental proteolytic catabolism (eg, Desulfovibrionaceae) significantly decreased. Fiber addition to the HM food led to significant changes in saccharolytic/proteolytic bacteria. Higher levels of free saccharides in feces upon fiber addition to either food indicated increased saccharolysis. Fiber addition to the GR food decreased levels of fecal free amino acids, indicating decreased proteolysis. Addition of fiber decreased fecal pH for both foods but likely by different mechanisms: addition of fiber to the HM food led to increased straight-chain short-chain fatty acids (SCFAs) and no significant change in proteolytic branched-chain SFCAs, while in the GR food, fiber mainly led to decreased proteolytic branched-chain SFCAs. Other postbiotics related to intestinal health were consistently altered when fiber was added to either food. Plant-derived bioactive molecules were enriched in feces from dogs fed either food with added fiber, which could account for the observed modulation of the canine gut microbiome and shifts in metabolic capacity.

Effect of an extruded animal protein-free diet on fecal microbiota of dogs with food-responsive enteropathy

Background

Dietary interventions are thought to modify gut microbial communities in healthy individuals. In dogs with chronic enteropathies, resolution of dysbiosis, along with remission of clinical signs, is expected with treatment.

Hypothesis/Objective

To evaluate changes in the fecal microbiota in dogs with food‐responsive chronic enteropathy (FRE) and in healthy control (HC) dogs before and after an elimination dietary trial with an animal protein‐free diet (APFD).

Animals

Dogs with FRE (n = 10) and HC (n = 14).

Methods

Dogs were fed the APFD for 60 days. Fecal microbiota was analyzed by Illumina 16S rRNA sequencing and quantitative polymerase chain reaction (PCR).

Results

A significantly lower bacterial alpha‐diversity was observed in dogs with FRE compared with HC dogs at baseline, and compared with FRE dogs after the trial. Distinct microbial communities were observed in dogs with FRE at baseline compared with HC dogs at baseline and compared with dogs with FRE after the trial. Microbial communities still were different in FRE dogs after the trial compared with HC dogs at baseline. In HC dogs, the fecal microbiota did not show a significant modification after administration of the APFD.

Conclusion and Clinical Importance

Our results suggest that, in FRE dogs, treatment with the APFD led to a partial recovery of the fecal microbiota by significantly increasing microbiota richness, which was significantly closer to a healthy microbiota after the treatment. In contrast, no changes were detected in the fecal microbiota of HC dogs fed the same APFD.

Evaluation of the Epithelial Barrier Function and Ileal Microbiome in an Established Necrotic Enteritis Challenge Model in Broiler Chickens

Necrotic enteritis (NE) is a recognized multifactorial disease that cost annually to the poultry industry around $2 billion. However, diverse aspects related to its presentation are not completely understood, requiring further studies using known induction experimental models. Therefore, the purpose of this study was to measure the changes occurring in performance, intestinal integrity and ileal microbiome using a previously established NE-challenge model. Chickens were assigned to a negative control group (NC) or a positive control group (PC). In the PC, broilers were orally gavaged with Salmonella Typhimurium (ST) (1 × 107 cfu/chick) at day 1, Eimeria maxima (EM) (2.5 × 104 oocyst/chick) at day 18 and Clostridium perfringens (CP) (1 × 108 cfu/chick/day) at 23-24 days of age. Weekly, body weight (BW), body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were evaluated. Morbidity and mortality were determined throughout the study, and NE lesion scores were recorded at day 25. Additionally, blood and liver samples were collected to measure gut permeability as determined by levels of serum fluorescein isothiocyanate-dextran (FITC-d) and bacterial translocation (BT). Ileal contents were processed for 16S rRNA gene-based microbiome analysis. Performance parameters and intestinal permeability measurements were negatively impacted in the PC resulting in elevated serum FITC-d and BT with a -6.4% difference in BWG. The NE lesion score in PC (1.97 vs. 0.00) was significantly higher in comparison to NC, although there was no difference in mortality. The microbiome analysis showed a dramatic shift of ileal microbiomes in PC groups as compared to NC (ANOSIM: R = 0.76, P = 0.001). The shift was characterized by reduced abundance of the phylum Actinobacteria (P < 0.01), and increased abundance of the genera Butyrivibrio, Lactobacillus, Prevotella and Ruminococcus in PC compared to NC (P < 0.05). Expectedly, Clostridium was found higher in PC (2.98 ± 0.71%) as compared to NC (1.84 ± 0.36%), yet the difference was not significant. In conclusion, results of the present study showed the different intestinal epithelial and microbiological alterations occurring in an established NE-challenge model that considers paratyphoid Salmonella infections in young chicks as an important predisposing factor for presentation of NE.

The fecal microbiome and metabolome differs between dogs fed Bones and Raw Food (BARF) diets and dogs fed commercial diets

INTRODUCTION

Feeding a Bones and Raw Food (BARF) diet has become an increasing trend in canine nutrition. Bones and Raw Food diets contain a high amount of animal components like meat, offal, and raw meaty bones, combined with comparatively small amounts of plant ingredients like vegetables and fruits as well as different sorts of oil and supplements. While many studies have focused on transmission of pathogens via contaminated meat and on nutritional imbalances, only few studies have evaluated the effect of BARF diets on the fecal microbiome and metabolome. The aim of the study was to investigate differences in the fecal microbiome and the metabolome between dogs on a BARF diet and dogs on a commercial diet (canned and dry dog food).

METHODS

Naturally passed fecal samples were obtained from 27 BARF and 19 commercially fed dogs. Differences in crude protein, fat, fiber, and NFE (Nitrogen-Free Extract) between diets were calculated with a scientific nutrient database. The fecal microbiota was analyzed by 16S rRNA gene sequencing and quantitative PCR assays. The fecal metabolome was analyzed in 10 BARF and 9 commercially fed dogs via untargeted metabolomics approach.

RESULTS

Dogs in the BARF group were fed a significantly higher amount of protein and fat and significantly lower amount of NFE and fiber. There was no significant difference in alpha-diversity measures between diet groups. Analysis of similarity (ANOSIM) revealed a significant difference in beta-diversity (p < 0.01) between both groups. Linear discriminant analysis effect size (LefSe) showed a higher abundance of Lactobacillales, Enterobacteriaceae, Fusobacterium and, Clostridium in the BARF group while conventionally fed dogs had a higher abundance of Clostridiaceae, Erysipelotrichaceae, Ruminococcaceae, and Lachnospiraceae. The qPCR assays revealed significantly higher abundance of Escherichia coli (E. coli) and Clostridium (C.). perfringens and an increased Dysbiosis Index in the BARF group. Principal component analysis (PCA) plots of metabolomics data showed clustering between diet groups. Random forest analysis showed differences in the abundance of various components, including increased 4-hydroxybutryric acid (GBH) and 4-aminobutyric acid (GABA) in the BARF group. Based on univariate statistics, several metabolites were significantly different between diet groups, but lost significance after adjusting for multiple comparison. No differences were found in fecal bile acid concentrations, but the BARF group had a higher fecal concentration of cholesterol in their feces compared to conventionally fed dogs.

CONCLUSION

Microbial communities and metabolome vary significantly between BARF and commercially fed dogs.

Characterization of the fecal and mucosa-associated microbiota in dogs with colorectal epithelial tumors

Colorectal epithelial tumors occur spontaneously in dogs, and the pathogenesis seems to parallel that of humans. The development of human colorectal tumorigenesis has been linked to alterations in the composition of the intestinal microbiota. This study characterized the fecal- and mucosa-associated microbiota in dogs with colorectal epithelial tumors (n = 10). The fecal microbiota was characterized by 16S rDNA analysis and compared with that of control dogs (n = 13). We also determined the mucosa-associated microbiota composition in colonic tumor tissue (n = 8) and in adjacent non-tumor tissue (n = 5) by 16S rDNA- and rRNA profiling. The fecal microbial community structure in dogs with tumors was different from that of control samples and was distinguished by oligotypes affiliated with Enterobacteriaceae, Bacteroides, Helicobacter, Porphyromonas, Peptostreptococcus and Streptococcus, and lower abundance of Ruminococcaceae, Slackia, Clostridium XI and Faecalibacterium. The overall community structure and populations of mucosal bacteria were not different based on either the 16S rDNA or the 16S rRNA profile in tumor tissue vs. adjacent non-tumor tissue. However, the proportion of live, potentially active bacteria appeared to be higher in non-tumor tissue compared with tumor tissue and included Slackia, Roseburia, unclass. Ruminococcaeceae, unclass. Lachnospiraceae and Oscillibacter. Colorectal tumors are rarely diagnosed in dogs, but despite this limitation, we were able to show that dogs with colorectal tumors have distinct fecal microbiota profiles. These initial results support the need for future case-control studies that are adequately powered, as well as age-matched and breed-matched, in order to evaluate the influence of bacteria on colorectal cancer etiopathogenesis and to determine whether the bacteria may have potential as biomarkers in clinical settings.

The Gastrointestinal Microbiome: A Review

The gastrointestinal microbiome is a diverse consortium of bacteria, archaea, fungi, protozoa, and viruses that inhabit the gut of all mammals. Studies in humans and other mammals have implicated the microbiome in a range of physiologic processes that are vital to host health including energy homeostasis, metabolism, gut epithelial health, immunologic activity, and neurobehavioral development. The microbial genome confers metabolic capabilities exceeding those of the host organism alone, making the gut microbiome an active participant in host physiology. Recent advances in DNA sequencing technology and computational biology have revolutionized the field of microbiomics, permitting mechanistic evaluation of the relationships between an animal and its microbial symbionts. Changes in the gastrointestinal microbiome are associated with diseases in humans and animals including inflammatory bowel disease, asthma, obesity, metabolic syndrome, cardiovascular disease, immune-mediated conditions, and neurodevelopmental conditions such as autism spectrum disorder. While there remains a paucity of data regarding the intestinal microbiome in small animals, recent studies have helped to characterize its role in host animal health and associated disease states. This review is intended to familiarize small animal veterinarians with recent advances in the field of microbiomics and to prime them for a future in which diagnostic tests and therapies will incorporate these developments into clinical practice.

The response of canine faecal microbiota to increased dietary protein is influenced by body condition

Background

High protein diets shift the faecal microbiota into a more unfavourable composition in obese humans. In lean dogs, higher protein consumption is accompanied with increased production of putrefactive fermentation products, whereas obese dogs have a different gut microbiota compared to lean dogs. Still, the impact of high dietary protein on gut microbiota in obese dogs remains unclear. The aim of this study was to investigate faecal microbial changes in lean and obese dogs in response to two different levels of dietary protein.

Six healthy lean and six obese Beagles were fed a high protein diet (HP) and a low protein diet (LP) for 28 days each in a crossover design. Denaturing gradient gel electrophoresis and quantitative PCR were performed on faecal samples for microbial profiling. Plasma acylcarnitine and fermentation metabolites were measured.

Results

Dogs fed HP had higher concentrations of protein fermentation metabolites including faecal ammonia, isovalerate, isobutyrate, phenol, indole, serum indoxyl sulphate and plasma 3-OH isovalerylcarnitine compared to dogs fed LP, whereas no changes in faecal concentrations of acetate and butyrate were observed. The abundances of clostridial clusters IV and XIVa, covering the majority of butyrate-producing bacteria, and of the butyrate kinase gene, one of the terminal genes of the butyrate synthesis pathway were higher in dogs on HP compared to LP. Significant interactions between diet and body condition were found for the abundance of Firmicutes, Lactobacillus and clostridial cluster I. The similarity coefficient of faecal microbiota between the two diets was smaller in obese dogs than in lean dogs.

Conclusions

High protein diet increased the abundance and activity of butyrate-producing bacteria in Beagles independent of the body condition. In addition, increasing dietary protein content had a greater overall impact on faecal microbiota in obese compared to lean dogs.

Electronic supplementary material

The online version of this article (10.1186/s12917-017-1276-0) contains supplementary material, which is available to authorized users.

Fecal microbiome in dogs with inflammatory bowel disease and intestinal lymphoma

Although alteration of commensal microbiota is associated with chronic gastrointestinal (GI) diseases such as inflammatory bowel disease (IBD) in dogs, the microbiota composition in intestinal lymphoma, an important differential diagnosis of canine IBD, has not been investigated. The objective of this study was to compare the fecal microbiota in dogs with IBD, dogs with intestinal lymphoma, and healthy dogs. Eight dogs with IBD, eight dogs with intestinal lymphoma, and fifteen healthy dogs were included in the study. Fecal samples were analyzed by 16S rRNA gene next-generation sequencing. Rarefaction analysis failed to reveal any difference in bacterial diversity among healthy dogs and diseased dogs. Based on PCoA plots of unweighted UniFrac distances, the bacterial composition in dogs with intestinal lymphoma was different from those observed in dogs with IBD and healthy dogs. When compared with healthy dogs, intestinal lymphoma subjects showed significant increases in organisms belonging to the Eubacteriaceae family. The proportion of the family Paraprevotellaceae and the genus Porphyromonas was significantly higher in dogs with IBD compared to healthy dogs. These observations suggest that dysbiosis is associated with intestinal lymphoma as well as IBD in dogs.

Succession and Fermentation Products of Grass Carp (Ctenopharyngodon idellus) Hindgut Microbiota in Response to an Extreme Dietary Shift

Dietary intake affects the structure and function of microbes in host intestine. However, the succession of gut microbiota in response to changes in macronutrient levels during a long period of time remains insufficiently studied. Here, we determined the succession and metabolic products of intestinal microbiota in grass carp (Ctenopharyngodon idellus) undergoing an abrupt and extreme diet change, from fish meal to Sudan grass (Sorghum sudanense). Grass carp hindgut microbiota responded rapidly to the diet shift, reaching a new equilibrium approximately within 11 days. In comparison to animal-diet samples, Bacteroides, Lachnospiraceae and Erysipelotrichaceae increased significantly while Cetobacterium decreased significantly in plant-diet samples. Cetobacterium was negatively correlated with Bacteroides, Lachnospiraceae and Erysipelotrichaceae, while Bacteroides was positively correlated with Lachnospiraceae. Predicted glycoside hydrolase and polysaccharide lyase genes in Bacteroides and Lachnospiraceae from the Carbohydrate-Active enZymes (CAZy) database might be involved in degradation of the plant cell wall polysaccharides. However, none of these enzymes was detected in the grass carp genome searched against dbCAN database. Additionally, a significant decrease of short chain fatty acids levels in plant-based samples was observed. Generally, our results suggest a rapid adaption of grass carp intestinal microbiota to dietary shift, and that microbiota are likely to play an indispensable role in nutrient turnover and fermentation.

A diet change from dry food to beef induces reversible changes on the faecal microbiota in healthy, adult client-owned dogs

BACKGROUND

Diet has a major influence on the composition of the gut microbiota, whose importance for gut health and overall well-being is increasingly recognized. Knowledge is limited regarding health implications, including effects on the faecal microbiota, of feeding a diet with high content of red meat to dogs, despite some owners' apparent preference to do so. The aim of this study was to evaluate how a diet change from commercial dry food to one with a high content of boiled minced beef and vice versa influenced the faecal microbiota, and short chain fatty acid profile in healthy, adult, client-owned dogs.

RESULTS

The diet change influenced the faecal microbiota composition and diversity (Shannon diversity index). The most abundant OTUs in samples of dogs fed the dry food and high minced beef were affiliated with the species Faecalibacterium prausnitzii and Clostridia hiranonis respectively. The high minced beef diet apparently also influenced the short chain fatty acid profile, with increased isovaleric acid, as well as an increase in faecal pH. These effects were reversed when the commercial dry food was reintroduced in weeks 6 and 7.

CONCLUSIONS

Results of this study can aid in the understanding of how diet changes influence the faecal microbiota and metabolite content on a short-term basis. Long-term studies are required to investigate potential implications for canine gut and general health.

Raw meat based diet influences faecal microbiome and end products of fermentation in healthy dogs

BACKGROUND

Dietary intervention studies are required to deeper understand the variability of gut microbial ecosystem in healthy dogs under different feeding conditions and to improve diet formulations. The aim of the study was to investigate in dogs the influence of a raw based diet supplemented with vegetable foods on faecal microbiome in comparison with extruded food.

METHODS

Eight healthy adult Boxer dogs were recruited and randomly divided in two experimental blocks of 4 individuals. Dogs were regularly fed a commercial extruded diet (RD) and starting from the beginning of the trial, one group received the raw based diet (MD) and the other group continued to be fed with the RD diet (CD) for a fortnight. After 14 days, the two groups were inverted, the CD group shifted to the MD and the MD shifted to the CD, for the next 14 days. Faeces were collected at the beginning of the study (T0), after 14 days (T14) before the change of diet and at the end of experimental period (T28) for DNA extraction and analysis of metagenome by sequencing 16SrRNA V3 and V4 regions, short chain fatty acids (SCFA), lactate and faecal score.

RESULTS

A decreased proportion of Lactobacillus, Paralactobacillus (P < 0.01) and Prevotella (P < 0.05) genera was observed in the MD group while Shannon biodiversity Index significantly increased (3.31 ± 0.15) in comparison to the RD group (2.92 ± 0.31; P < 0.05). The MD diet significantly (P < 0.05) decreased the Faecal Score and increased the lactic acid concentration in the feces in comparison to the RD treatment (P < 0.01). Faecal acetate was negatively correlated with Escherichia/Shigella and Megamonas (P < 0.01), whilst butyrate was positively correlated with Blautia and Peptococcus (P < 0.05). Positive correlations were found between lactate and Megamonas (P < 0.05), Escherichia/Shigella (P < 0.01) and Lactococcus (P < 0.01).

CONCLUSION

These results suggest that the diet composition modifies faecal microbial composition and end products of fermentation. The administration of MD diet promoted a more balanced growth of bacterial communities and a positive change in the readouts of healthy gut functions in comparison to RD diet.

The Effects of Moderate Whole Grain Consumption on Fasting Glucose and Lipids, Gastrointestinal Symptoms, and Microbiota

This study was designed to determine if providing wheat, corn, and rice as whole (WG) or refined grains (RG) under free-living conditions will change parameters of health over a six-week intervention in healthy, habitual non-WG consumers. Measurements of body composition, fecal microbiota, fasting blood glucose, total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and triglycerides were made at baseline and post intervention. Subjects were given adequate servings of either WG or RG products based on their caloric need and asked to keep records of grain consumption, bowel movements, and GI symptoms weekly. After six weeks, subjects repeated baseline testing. Significant decreases in total, LDL, and non-HDL cholesterol were seen after the WG treatments but were not observed in the RG treatment. During Week 6, bowel movement frequency increased with increased WG consumption. No significant differences in microbiota were seen between baseline and post intervention, although, abundance of order Erysipelotrichales increased in RG subjects who ate more than 50% of the RG market basket products. Increasing consumption of WGs can alter parameters of health, but more research is needed to better elucidate the relationship between the amount consumed and the health-related outcome.

Impact of macronutrients on gut microbiota

The human gastrointestinal tract is colonized by microbial communities that have important effects on immune function, nutrient processing, and a broad range of other host activities. Diet and other environmental factors can modulate the composition and metabolic activity of the gut microbiota, which in turn impacts health. On the other hand, microbiota and its collective genomes provide us with genetic and metabolic attributes we have not been required to evolve on our own, including the ability to harvest nutrients such as polysaccharides. This review will focus on the impact of dietary macronutrients (carbohydrate, protein and fat) on the microbial ecology and metabolism within the intestine, and explore some of the consequences for animal health.

Understanding the canine intestinal microbiota and its modification by pro-, pre- and synbiotics - what is the evidence?

Interest in the composition of the intestinal microbiota and possibilities of its therapeutic modifications has soared over the last decade and more detailed knowledge specific to the canine microbiota at different mucosal sites including the gut is available. Probiotics, prebiotics or their combination (synbiotics) are a way of modifying the intestinal microbiota and exert effects on the host immune response. Probiotics are proposed to exert their beneficial effects through various pathways, for example production of antimicrobial peptides, enhancing growth of favourable endogenous microorganisms, competition for epithelial colonisation sites and immune‐modulatory functions. Despite widespread use of pro‐, pre‐ and synbiotics, scientific evidence of their beneficial effects in different conditions of the dog is scarce. Specific effects of different strains, their combination or their potential side‐effects have not been evaluated sufficiently. In some instances, in vitro results have been promising, but could not be transferred consistently into in vivo situations. Specific canine gastrointestinal (GI) diseases or conditions where probiotics would be beneficial, their most appropriate dosage and application have not been assessed extensively. This review summarises the current knowledge of the intestinal microbiome composition in the dog and evaluates the evidence for probiotic use in canine GI diseases to date. It wishes to provide veterinarians with evidence‐based information on when and why these products could be useful in preventing or treating canine GI conditions. It also outlines knowledge about safety and approval of commercial probiotic products, and the potential use of faecal microbial transplantation, as they are related to the topic of probiotic usage.

Diet shapes the gut microbiota of the omnivorous cockroach Blattella germanica

The gut microbiota of insects contributes positively to the physiology of its host mainly by participating in food digestion, protecting against pathogens, or provisioning vitamins or amino acids, but the dynamics of this complex ecosystem is not well understood so far. In this study, we have characterized the gut microbiota of the omnivorous cockroach Blattella germanica by pyrosequencing the hypervariable regions V1-V3 of the 16S rRNA gene of the whole bacterial community. Three diets differing in the protein content (0, 24 and 50%) were tested at two time points in lab-reared individuals. In addition, the gut microbiota of wild adult cockroaches was also analyzed. In contrast to the high microbial richness described on the studied samples, only few species are shared by wild and lab-reared cockroaches, constituting the bacterial core in the gut of B. germanica. Overall, we found that the gut microbiota of B. germanica is highly dynamic as the bacterial composition was reassembled in a diet-specific manner over a short time span, with no-protein diet promoting high diversity, although the highest diversity was found in the wild cockroaches analyzed. We discuss how the flexibility of the gut microbiota is probably due to its omnivorous life style and varied diets.