Molecular characterization of intergeneric hybrids between Malus and Pyrus

Apple(Malus)and pear(Pyrus)are economically important fruit crops well known for their unique textures,f lavours,and nutritional qualities.Both genera are characterised by a distinct pattern of secondary metabolites,which directly affect not only resistance to certain diseases,but also have significant impacts on the f lavour and nutritional value of the fruit.The identical chromosome numbers,similar genome size,and their recent divergence date,together with DNA markers have shown that apple and pear genomes are highly co-linear.This study utilized comparative genomic approaches,including simple sequence repeats,high resolution single nucleotide polymorphism melting analysis,and single nucleotide polymorphism chip analysis to identify genetic differences among hybrids of Malus and Pyrus,and F2 offspring.This research has demonstrated and validated that these three marker types,along with metabolomics analysis are very powerful tools to detect and confirm hybridity of progeny derived from crosses between apple and pear in both cross directions.Furthermore,this work analysed the genus-specific metabolite patterns and the resistance to fire blight(Erwinia amylovora)in progeny.The findings of this work will enhance and accelerate the breeding of novel tree fruit crops that benefit producers and consumers,by enabling marker assisted selection of desired traits introgressed between pear and apple.

Phenotypic and Molecular Characterization of <i>Phaseolus vulgaris</i>Plants from Non-Cryopreserved and Cryopre-served Seeds

The objective of this work was to evaluate if cryostorage of Phaseolus vulgaris L. seeds induced variations in regenerated plants at the phenotypic and molecular levels. A series of agricultural traits was measured on plants grown from control, non-cryopreserved and cryopreserved seeds, and the genetic stability of plants of the second generation was analysed at selected microsatellite loci. The phenotype of the second generation plants was evaluated as well. No statistically significant phenotypic differences were observed for the parameters measured, neither in the first nor in the second generations. Averaging both treatments, about 76% of the seeds had germinated 10 days after sowing. At harvest we recorded plants with about 73 cm in height, 13 stem internodes, 25 fruits, 103 grains and 4 grains per fruit. One hundred seeds weighted about 26 g. The genetic analyses performed on the second generation plants using six nuclear Simple Sequences Repeats (SSR) markers revealed no changes in microsatellite length between control and cryopreserved samples, implying that there was no effect of seed liquid nitrogen exposure on genome integrity. The phenotypic and molecular results reported here confirm that cryostorage is an efficient and reliable technique to conserve P. vulgaris seeds and regenerate true-to-type plants.

Transcriptional regulation of MdmiR285N microRNA in apple(Malus x domestica)and the heterologous plant system Arabidopsis thaliana

Malus x domestica microRNA MdmiR285N is a potential key regulator of plant immunity,as it has been predicted to target 35 RNA transcripts coding for different disease resistance proteins involved in plant defense to pathogens.In this study,the promoter region of MdmiR285N was isolated from the apple genome and analyzed in silico to detect potential regulatory regions controlling its transcription.A complex network of putative regulatory elements involved in plant growth and development,and in response to different hormones and stress conditions,was identified.Activity of theβ-Glucoronidase(GUS)reporter gene driven by the promoter of MdmiR285N was examined in transgenic apple,demonstrating that MdmiR285N was expressed during the vegetative growth phase.Similarly,in transgenic Arabidopsis thaliana,spatial and temporal patterns of GUS expression revealed that MdmiR285N was differentially regulated during seed germination,vegetative phase change,and reproductive development.To elucidate the role of MdmiR285N in plant immunity,MdmiR285N expression in wild-type apple plants and GUS activity in transgenic apple and Arabidopsis thaliana plants were monitored in response to Erwinia amylovora and Pseudomonas syringae pv.Tomato DC3000.A significant decrease of MdmiR285N levels and GUS expression was observed during host-pathogen infections.Overall,these data suggest that MdmiR285N is involved in the biotic stress response,plant growth,and reproductive development.

Factors Influencing Salmonella Contamination and Microbial Load of Beef Carcass at the Yaoundé Slaughterhouse, Cameroon

Delivering safe beef carcass at the Yaoundéabattoir is challenged by improper Good Manufacturing Practices(GMP)and poor hygiene practices leading to microbial contamination during slaughtering and dressing processes.This study was to estimate the safety and quality of carcasses via detection of Salmonella and evaluation of aerobic colony count(ACC),Enterobacteriaceae count(EC).Swabs of carcass from 145 cattle were collected at three different sites.Hides&anus from live cattle,butchers’hands,and processing environment were also swabbed.Detection of Salmonella was carried out following ISO 6579.ACC and EC were evaluated using ISO 4833 and ISO 21528-2.Beef carcass registered higher Salmonella prevalence(4.37%).Generally,microbial load of carcass was beyond FAO microbiological criteria.The post-evisceration carcasses had the highest isolation rate of Salmonella(52.63%).Both sampling site and seasonal variations had statistically significant impact(p<0.05)on microbial load.Our results reflected poor conditions of slaughtering and inadequate hygienic practices.There is an urgent need for training the abattoir personnel on the GMP and need for the implementation of Hazard Analysis and Critical Control Point(HACCP)principles throughout the slaughtering process at the Yaoundéslaughterhouse.

Breed and adaptive response modulate bovine peripheral blood cells＇ transcriptome

Background： Adaptive response includes a variety of physiological modifications to face changes in external or internal conditions and adapt to a new situation. The acute phase proteins（APPs） are reactants synthesized against environmental stimuli like stress, infection, inflammation.Methods： To delineate the differences in molecular constituents of adaptive response to the environment we performed the whole-blood transcriptome analysis in Italian Holstein（IH） and Italian Simmental（IS） breeds. For this, 663 IH and IS cows from six commercial farms were clustered according to the blood level of APPs. Ten extreme individuals（five APP＋ and APP-variants） from each farm were selected for the RNA-seq using the Illumina sequencing technology. Differentially expressed（DE） genes were analyzed using dynamic impact approach（DIA）and DAVID annotation clustering. Milk production data were statistically elaborated to assess the association of APP＋ and APP-gene expression patterns with variations in milk parameters.Results： The overall de novo assembly of cDNA sequence data generated 13,665 genes expressed in bovine blood cells. Comparative genomic analysis revealed 1,152 DE genes in the comparison of all APP＋ vs. all APP-variants; 531 and 217 DE genes specific for IH and IS comparison respectively. In all comparisons overexpressed genes were more represented than underexpressed ones. DAVID analysis revealed 369 DE genes across breeds, 173 and 73 DE genes in IH and IS comparison respectively. Among the most impacted pathways for both breeds were vitamin B6 metabolism, folate biosynthesis, nitrogen metabolism and linoleic acid metabolism.Conclusions： Both DIA and DAVID approaches produced a high number of significantly impacted genes and pathways with a narrow connection to adaptive response in cows with high level of blood APPs. A similar variation in gene expression and impacted pathways between APP＋ and APP-variants was found between two studied breeds. Such similarity was also confirmed by annotation clustering of the DE genes. However, IH breed showed higher and more differentiated impacts compared to IS breed and such particular features in the IH adaptive response could be explained by its higher metabolic activity. Variations of milk production data were significantly associated with APP＋ and APP-gene expression patterns.

Combined forest and soil management after a catastrophic event

At the end of October 2018,a storm of unprecedented strength severely damaged the forests of the eastern sector of the Italian Alps.The affected forest area covers 42,500 ha.The president of one of the damaged regions asked for help from the University of Padua.After eight months of discussion,the authors of this article wrote a consensus text.The sometimes asper debate brought to light some crucial aspects:1)even experienced specialists may have various opinions based on scientific knowledge that lead to conflicting proposals for action.For some of them there is evidence that to restore a destroyed natural environment it is more judicious to do nothing;2)the soil corresponds to a living structure and every ecosystem’s management should be based on it;3)faced with a catastrophe,people and politicians find themselves unarmed,also because they rarely have the scientific background to understand natural processes.Yet politicians are the only persons who make the key decisions that drive the economy in play and therefore determine the near future of our planet.This article is an attempt to respond directly to the governor of a region who formally and prudently asked a university department called"Land,Environment,Agriculture and Forestry"for help before taking decisions;4)the authors also propose an artistic interpretation of facts(uncontrolled storm)and conclusions(listen to the soil).Briefly,the authors identify the soil as an indispensable source for the renewal of the destroyed forest,give indications on how to prepare a map of the soils of the damaged region,and suggest to anchor on this soil map a series of silvicultural and soil management actions that will promote the soil conservation and the faster recovery of the natural dynamic stability and resilience.

Consumer attitudes towards the mountain product label: Implications for mountain development

To protect and promote the originality and authenticity of mountain foodstuffs, the European Union set Regulation No 1151/2012 to create the optional quality term "mountain product". Our research aimed at exploring the attractiveness of the mountain product label for consumers, considering both attitude towards the label itself and purchase intentions. We propose a model to investigate relationships between four latent constructs-mountain attractiveness, mountain food attractiveness, attitude towards the mountain product label, and purchase intention-which have been tested, thus confirming the statistical relevance of the relationships. All 47 items selected for describing the latent constructs are suitable for this purpose. Ridge and LASSO results also show that 17 items of the first three constructs are relevant in explaining purchase intentions. Some contextual variables, such as age, income, geographical origin of consumers, and knowledge of mountain products and mountains for tourism purposes, can positively influence consumers’ behavior. These findings could support the design of mountain development strategies, in particular marketing actions for both the product and the territory.

A plant-based diet supplemented with Hermetia illucens alone or in combination with poultry by-product meal:one step closer to sustainable aquafeeds for European seabass

Background:Increasing demand for high-value fish species and pressure on forage fish is challenging aquaculture to ensure sustainable growth by replacing protein sources in aquafeeds with plant and terrestrial animal proteins,without compromising the economic value and quality of the final fish product.In the present study,the effects of a plant protein-based diet(CV),two plant-based diets in which graded amounts of plan protein mixtures were replaced with Hermetia illucens meal alone(VH10)or in combination with poultry by-product meal(PBM)(VH10P30),a fishmeal(FM)diet(CF)and an FM diet supplemented with H.illucens(FH10)on growth performance,gut health and homeostasis of farmed subadult European seabass were tested and compared.Results:Fish fed the VH10 and VH10P30 diets showed the highest specific growth rates and lowest feed conversion ratios among the tested groups.Expectedly,the best preservation of PI morphology was observed in fish fed the CF or FH10 diets,while fish fed the CV diet exhibited significant degenerative changes in the proximal and distal intestines.However,PBM supplementation mitigated these effects and significantly improved all gut morphometric parameters in the VH10P30 group.Partial substitution of the plant mixture with insect meal alone or PBM also induced most BBM genes and activated BBM enzymes,suggesting a beneficial effect on intestinal digestive/absorption functions.Regarding intestinal microbiota,fish fed diets containing H.illucens meal(FH10,VH10,VH10P30)had the highest richness of bacterial communities and abundance of beneficial genera such as Lactobacillus and Bacillus.On the other hand,fish fed CV had the highest microbial diversity but lost a significant component of fish intestinal microbiota,the phylum Bacteroidetes.Finally,skin pigmentation most similar to that of farmed or even wild seabass was also observed in the fish groups fed CF,FH10 or VH10P30.Conclusion:Plant-based diets supplemented with PBM and H.illucens pupae meal have great potential as alternative diets for European seabass,without affecting growth performance,gut homeostasis,or overall fitness.This also highlights the importance of animal proteins in diets of European seabass,as the addition of a small amount of these alternative animal protein sources significantly improved all measured parameters.

Solanaceae Evolutionary Dynamics of the <i>I</i>2-NBS Domain

In Solanaceae family several plant resistant genes to pathogen (R-genes) have been mapped and cloned. Most of them encode Nucleotide Binding Site Leucine Rich Repeat domain (NBS-LRR) protein. However, little is known about the resistance genes variability pattern and the evolutionary process acting on different species belonging to the same family. The aims of the present work, was to genotype and study the evolutionary relationship of fifty wild tomato accessions using the I2 resistance gene sequences. Thirty-three new candidate homologues I2 resistance gene nucleotide sequence were obtained from wild tomato species. Nucleotide polymorphisms in I2-NBS domain was detected in wild tomato species: diversity could have accumulated over a long time and species sorting could have produced new variants. In order to study the NBS-LRR domain variability we analyzed the evolution process acting on the amino acid sequence. The FEL method (codon Model) based on dN/dS, was used to estimate the presence of positive, negative and neutral selection acting on each codon. The I2-NBS domain sequence data studied seems to be under a general purification process of evolution. However, intermittent bouts of positive selection sites were detected in high variable regions. Phylogenetic analysis conducted within the Solanaceae family shows that the Solanum genus is under a rapid adaptative divergence process and Nicotiana and Capsicum clustered separately;Solanum peruvianum, in particular, displayed to be the most polymorphic specie. These results might be important for the identification of new sources of resistance genes to tomato pathogens.

AGRI-ENVIRONMENTAL ASSESSMENT OF CONVENTIONAL AND ALTERNATIVE BIOENERGY CROPPING SYSTEMS PROMOTING BIOMASS PRODUCTIVITY

Bioenergy,currently the largest renewable energy source in the EU(64%of the total renewable energy consumption),has sparked great interest to meet the32%renewable resources for the 2030 bioeconomy goal.The design of innovative cropping systems informed by bioeconomy imperatives requires the evaluate of the effects of introducing crops for bioenergy into conventional crop rotations.This study aimed to assess the impacts of changes in conventional cropping systems in mixed dairy cattle farms redesigned to introduce bioenergy crops either by increasing the biomass production through an increase of cover crops,while keeping main feed/food crops,or by substituting food crops with an increase of the crop rotation length.The assessment is based on the comparison between conventional and innovative systems oriented to feed and biogas production,with and without tillage,to evaluate their agri-environmental performances(biomass production,nitrogen fertilization autonomy,greenhouse gas emissions and biogas production).The result showed higher values in the biogas cropping system than in the conventional and feed ones for all indicators,biomass productivity(27%and20%higher,respectively),nitrogen fertilization autonomy(26%and 73%higher,respectively),methanogenic potential(77%and 41%higher,respectively)and greenhouse gas emissions(15%and 3%higher,respectively).There were no negative impacts of no-till compared to the tillage practice,for all tested variables.The biogas cropping system showed a better potential in terms of agri-environmental performance,although its greenhouse gas emissions were higher.Consequently,it would be appropriate to undertake a multicriteria assessment integrating agri-environmental,economic and social performances.

Spatiotemporal behavior of predators and prey in an arid environment of Central Asia

The mechanisms of interactions between apex and smaller carnivores may range from competition to facilitation.Conversely,interactions between predators and prey are mainly driven by the prey reducing the likelihood of encounters with predators.In this study,we investigated(1)the spatiotemporal interactions between an apex(the snow leopard)and a meso-predator(the red fox),and(2)the temporal interactions between the snow leopard and its potential prey(Siberian ibex,argali,Asian wild ass,Tolai hare)through camera trapping in the Mongolian Great Gobi-A.The probability of occurrence for the red fox was higher in the presence of the snow leopard than in its absence.Moreover,the red fox activity pattern matched that of the snow leopard,with both species mostly active at sunset.This positive spatiotemporal interaction suggests that the presence of the snow leopard may be beneficial for the red fox in terms of scavenging opportunities.However,other explanations may also be possible.Amongst prey,the Siberian ibex and the argali were mainly active during the day,whereas the Asian wild ass and the Tolai hare were more nocturnal.These findings suggest that potential prey(especially the Siberian ibex and the argali)may shape their behavior to decrease the opportunity for encounters with the snow leopard.Our results have revealed complex interactions between apex and smaller predators andbetween apexpredatorand its potential prey.

Adsorption of Phosphate onto Ferrihydrite and Ferrihydrite-Humic Acid Complexes

The adsorption of phosphate onto ferrihydrite(FH) and two FH-humic acid(HA) complexes, obtained by co-precipitating FH with low(FH-HA1) and relatively high amounts of humic acid(FH-HA2), was studied through kinetics and isotherm experiments to determine the differences in phosphate adsorption between FH-HA complexes and FH and to reveal the mechanisms of phosphate adsorption onto two soil compositions. The isoelectric point(IEP) and the specific surface area(SSA) of the mineral decreased as the particle porosity of the mineral increased, which corresponded to an increase in the amount of organic carbon. The adsorption capacity of phosphate was higher on FH than on FH-HA1 and FH-HA2 at the scale of micromoles per kilogram. The initial adsorption rate and adsorption affinity of phosphate decreased with an increase in the amount of HA in the mineral. The sensitivity of phosphate adsorption to the change in the pH was greater for FH than for FH-HA complexes. Ionic strength did not affect the adsorption of phosphate onto FH and FH-HA1 at a lower p H, and the increase in the ionic strength promoted phosphate adsorption at a higher p H.However, for the FH-HA2 complex, the increase in the ionic strength inhibited the adsorption of phosphate onto FH-HA2 at a lower p H and increased the adsorption at a higher pH.

Contrasting responses of native and alien plant species to soil properties shed new light on the invasion of dune systems

Aims Among terrestrial ecosystems,coastal sandy dunes are particularly prone to alien plant invasion.Many studies related the invasion of dune habitats to anthropic causes,but less is known about the role of soil properties and plant traits in plant invasion.In this study,we tested the relationships between soil features and alien plant invasion in dune systems,focusing on the interplay between soil nutrients,soil salinity and plant functional traits.Methods Study sites were sandy barrier islands of the Marano and Grado lagoon(northern Adriatic Sea).One hundred plots(4 m×4 m)were selected within 10 areas according to the main habitats occurring along the ecological gradient of dune system(foredune,backdune and saltmarsh).In each plot,we recorded all plant species occurrence and abundance and we collected a soil core.For each soil sample,soil texture,conductivity(as proxy of soil salinity),organic carbon and nitrogen content were analyzed and related to the species number and cover of native and alien plants.Variation of main reproductive and vegetative functional traits among habitats was also analyzed for both alien and native species.Important Findings Soil properties were strongly related to overall plant diversity,by differently affecting alien and native species pools.In backdune,the most invaded habitat,a high soil conductivity limited the number of alien species,whereas the content of soil organic carbon increased along with alien plant abundance,suggesting also the occurrence of potential feedback processes between plant invasion and soil.We found a significant convergence between native and alien plant functional trait spectra only in backdune habitat,where environmental conditions ameliorate and plant competition increases.Our findings suggest that in harsh conditions only native specialized plants can thrive while at intermediate conditions,soil properties gradient acts in synergy with plant traits to curb/facilitate alien plant richness.

Instrumental and bio-monitoring of heavy metal and nanoparticle emissions from diesel engine exhaust in controlled environment

In the present article we characterized the emissions at the exhaust of a Common Rail （CR） diesel engine, representative of lightduty class, equipped with a catalyzed diesel particulate filter （CDPF） in controlled environment. The downstream exhausts were directly analyzed （for PM, CO, CO/, Oz, HCs, NOx） by infrared and electrochemical sensors, and SEM-EDS microscope; heavy metals were chemically analyzed using mosses and lichens in bags, and glass-fibre filters all exposed at the engine exhausts. The highest particle emission value was in the 7-54 nm size range; the peak concentration rose until one order of magnitude for the highest load and speed. Particle composition was mainly carbonaceous, associated to noticeable amounts of Fe and silica fibres. Moreover, the content of Cu, Fe, Na, Ni and Zn in both moss and lichen, and of A1 and Cr in moss, was significantly increased. Glass-fibre filters were significantly enriched in A1, B, Ba, Cu, Fe, Na, and Zn. The role of diesel engines as source of carbonaceous nanoparticles has been confirmed, while further investigations in controlled environment are needed to test the catalytic muffler as a possible source of silica fibres considered very hazardous for human health.

Chemical composition and Zn bioavailability of the soil solution extracted from Zn amended variable charge soils

A study on variable charge soils （volcanic Italian and podzolic Scottish soils） was performed to investigate the influence of soil properties on the chemical composition of soil solution. Zinc speciation, bioavallability and toxicity in the soil solution were examined. The soils were spiked with increasing amounts of Zn （0, 100, 200, 400 and 1000 mg/kg） and the soil solutions were extracted using rhizon soil moisture samplers. The pH, total organic carbon （TOC）, base cations, anions, total Zn and free Zn^2＋ in soil solution were analysed. A rapid bioassay with the luminescent bacterium Escherichia coli HB 101 pUCD607 was performed to assess Zn toxicity. The influence of soil type and Zn treatments on the chemical composition of soil solution and on Zn toxicity was considered and discussed. Different trends of total and free Zn concentrations, base cations desorption and luminescence of E. coli HB 101 pUCD607 were observed. The soil solution extracted from the volcanic soils had very low total and free Zn concentrations and showed specific Zn^2＋/Ca^2＋ exchange. The soil solution from the podzolic soil had much higher total and free Zn concentrations and showed no evidence of specific Zn^2＋/Ca^2＋ exchange. In comparison with the subalkaline volcanic soils, the acidic podzol showed enhanced levels of toxic free Zn^2＋ and consequently stronger effects on E. coli viability.

In vitro rumen fermentation of feed substrates added with chestnut tannins or an extract from Stevia rebaudiana Bertoni

Rumen fermentation parameters and microbiota were evaluated in 3 in vitro rumen fermentation experiments after addition of chestnut tannins(CWT)or an extract from Stevia rebaudiana Bertoni(SB)to substrates.A control(CTR)substrate was fermented alone or added with 1.5%of CWT or SB extracts in a batch culture system(Exp.1,fermentation in 500 mL for 24 h)and in a subsequent continuous culture system(Exp.2,fermentation in 2 L bottles for 9 d).Experiment 3 used the fermentation system of Exp.1 and tested 7 doses of each extract added to CTR(additions of 0.2%,0.4%,0.6%,0.8%,1.0%,1.2%and 1.4%for48 h).The addition of CWT lowered(P<0.01)the in vitro rumen ammonia concentration in all experiments and reduced the protozoa counts in Exp.1(P<0.05).In contrast,the SB extract did not modify the ammonia concentrations,but significantly lowered the protozoa counts in all 3 experiments(reduction of 47%and 20%in Exp.1 and 2,P<0.05;and a quadratic reduction in Exp.3,R^2=0.63,P<0.01).Neither extract affected the fermentation in terms of gas production(Exp.1 and 3)nor volatile fatty acids(VFA)yield(Exp.1 and 2),if we exclude a reduction at the highest CWT concentration in Exp.3.Changes in VFA profile were induced by CWT and were limited to reductions in the iso-valerate(P<0.01,in Exp.2)and iso-butyrate levels(P<0.01,Exp.2).The CWT increased the abundance of Prevotella ruminicola and Selenomonas ruminantium and decreased that of Ruminobacter amylophilus(P<0.01,P<0.05 and P<0.05,respectively).The SB extract increased the relative abundance of Treponema saccarophylum(P<0.05).Both of the studied substances had an impact on rumen metabolism,with SB reducing protozoa counts and CWT lowering the rumen ammonia concentration.The effects of both extracts on the rumen were appreciable at low dietary doses,and the negative impacts on fermentation were limited to the reduction in protein degradation with the addition of CWT.

Agroecological management of a soil-dwelling orthopteran pest in vineyards

The efficacy of different combinations of undervine and inter-row treatments for managing a soil-dwelling orthopteran pest, weta （Hemiandrus sp.）, in vineyards was investigated over 2 seasons. This insect damages vine buds, thus reducing subsequent grape yield. The undervine treatments comprised pea straw mulch, mussel shells, tick beans [Viciafaba Linn. var minor （Fab）], plastic sleeves on vine trunks （treated control） and control （no intervention）, while inter-rows contained either the existing vegetation or tick beans. Treatments were arranged in a randomized complete block design with 10 replicates. Data were collected on weta densities, damage to beans and components of yield. The latter were numbers of bud laid down per vine, shoots per bud, clusters per shoot, grape bunches per vine, bunch weight and yield. The undervine treatments significantly affected all variables except the number of shoots per bud. In contrast, none of the variables was significantly affected by the inter-row treatments or their interaction with undervine treatments, apart from weta density. At the end of the experiment, weta density in the shell treatment was about 58% lower than in the control. As a result, there was about 39% significant yield increase in that treatment compared to the control. Although the undervine beans and sleeves treatments increased yield, there were no reductions in weta density. With undervine beans, the insect fed on the bean plants instead of vine buds. Thus, yield in that treatment was approximately 28% higher than in the control. These results demonstrate that simple agroecological management approaches can reduce above-ground damage by soil-dwelling insects.

Effect of different starch sources in a raw meat-based diet on fecal microbiome in dogs housed in a shelter

A dietary intervention study was assessed to determine if different sources of starch in homemade diets could significantly modify fecal microbiome of dogs.Twenty-seven adult dogs were enrolled and fed a diet based on a mixture of rice and pasta with fresh raw meat(CD).After 90 d,8 dogs continued to receive CD diet,10 dogs received a diet made of a raw meat and a complementary food with rice as the main source of starch(B1),and 9 dogs were fed a diet with the same raw meat and a complementary food with potato as the main source of starch(B2).Samples of feces were collected from each dog in the mornings at the beginning of the study and after 15 d and analyzed for pH,ammonia N(N-NH3)and total N,short chain fatty acids(SCFA)and lactic acid.Relative abundance of fecal microbiota was assessed by sequencing and annotating the V3-V4 regions of the 16S rRNA.Total starch intake was similar between diets but differed in the in vitro rate digestion and in the resistant starch,which was higher in B2 than in B1 and CD diets.Dogs fed B2 diet showed lower(P<0.05)N-NH3 and pH but higher(P<0.05)molar proportion of lactic acid.Linear discriminant analysis of the genera relative abundances indicated a significant(P<0.01)increase of SMB53 genus at the end of the study in B1 diet and of Megamonas genus in B1 and B2 diets in comparison to CD diet.These results suggest that changes of starch source in a raw meat-based diet have limited effects on fecal microbiome in healthy dogs,but underline a high variability of microbiota among dogs.