Effect of dietary supplementation with Lactobacillus acidophilus D2/CSL (CECT 4529) on caecum microbioma and productive performance in broiler chickens

Plasma activated water effects on behavior, performance, carcass quality, biochemical changes, and histopathological alterations in quail

BACKGROUND

Plasma-activated water (PAW) is an innovative promising technology which could be applied to improve poultry health. The current study investigated the effects of drinking water supply with PAW on quail behaviour, performance, biochemical parameters, carcass quality, intestinal microbial populations, and internal organs histopathology. A total of 54 twenty-one-day-old Japanese quail chicks were randomly allotted to three treatments provided with PAW at doses 0, 1 ml (PAW-1), and 2 ml (PAW-2) per one litter drinking water. Each treatment contained 6 replicates (3 birds/ cage; one male and two females).

RESULTS

The results clarified that there were no significant (P > 0.05) changes in behaviour, and performance. For the biochemical indicators, the PAW-1 group showed significantly higher serum H2O2, total protein and globulin levels compared with the other groups (P = 0.015, < 0.001, and 0.019; respectively). PAW groups had significantly lower serum creatinine and urea levels than the control (P = 0.003). For the carcass quality, the internal organs relative weight between different treatments was not changed. In contrast, there was a significant increase in the meat colour, taste, and overall acceptance scores in PAW groups compared with the control one (P = 0.013, 0.001, and < 0.001; respectively). For the intestinal microbial population, lactobacilli count was significantly higher in PAW-2 compared with the control group (P = 0.014), while there were no changes in the total bacterial count between different treatment groups. Moreover, mild histological changes were recorded in the intestine, liver, and spleen of PAW groups especially PAW-2 compared with the control one.

CONCLUSIONS

PAW offered benefits, such as reducing creatine and urea levels, improving meat characteristics, and increasing lactobacilli count, all of which are crucial for sustainable quail farming. Therefore, further research is needed.

Effect of supplementation with Glycyrrhiza uralensis extract and Lactobacillus acidophilus on growth performance and intestinal health in broiler chickens

Intestinal microbiota community is an important factor affecting the nutritional and health status of poultry, and its balance is crucial for improving the overall health of poultry. The study aimed to investigate the effect of dietary supplementation with Glycyrrhiza uralensis extract (GUE), Lactobacillus acidophilus (Lac) and their combination (GL) on growth performance and intestinal health in broilers in an 84-day feeding experiment. Supplementary 0.1% GUE and 4.5×107 CFU/g Lac significantly increased average daily gain (ADG), and GL (0.1% GUE and 4.5×107 CFU/g Lac) increased ADG and average daily feed intake (ADFI), and decreased feed conversion rate (FCR) in broilers aged 29 to 84 d and 1 to 84 d. Dietary GUE, Lac and GL increased the superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activity and decreased Malondialdehyde (MDA) content in the jejunum mucosa of broilers, and increased secretory IgA (sIgA) content in broilers at 84 d. Moreover, GUE, Lac and GL increased cecal microbial richness and diversity, and modulated microbial community composition. Both GUE and Lac reduced the harmful bacteria Epsilonbacteraeota, Helicobacter, and H. pullorum at 28 d and Proteobacteria, Escherichia, and E. coli at 84 d, while Lac and GL increased beneficial bacteria Lactobacillus and L. gallinarum at 28 d. Compared with individual supplementation, GL markedly increased the SOD activity and the sIgA content, and reduced Helicobacter and Helicobacter pullorum. In conclusion, GUE and Lactobacillus acidophilus as feed additives benefit growth performance and intestinal health, and their combined use shows an even more positive effect in broilers.

Research Note: The effect of photoperiod on the NLRP3 inflammasome and gut microbiota in broiler chickens

The present study aimed to investigate the effect of photoperiod on the intestinal inflammation and gut microbiota. A total of 96 broiler chickens were divided into 2 groups and fed separately under 2 different photoperiods (12L:12D group and 23L:1D group) for 21 d. The results showed that the photoperiod of 23L:1D damaged duodenal tissue structure (intestinal villus erosion, mucosal epithelial cell detachment, and inflammatory cell infiltration), significantly increased the concentration of inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α) and significantly increased the mRNA expression levels and protein expression levels of NOD-, LRR-, pyrin domain-containing protein 3 (NLRP3) and caspase1 (P <0.05) compared with 12L:12D, which indicating that extended photoperiod induced intestinal injury and activated NLRP3 inflammasome. 16S rRNA sequencing analysis revealed that Bacteroides was significantly decreased, Ruminococcus_torques_group, norank_f_Desulfovibrionaceae, GCA-900066575, Defluviitaleaceae_UCG-011, Lachnospiraceae_FCS020_group, norank_f_UCG-010 and norank_f_norank_o_Clostridia_vadinBB60_group and were significantly increased in the 23L:1D group, compared with the 12L:12D group (P < 0.05). The correlation analysis between differential microbial communities and intestinal inflammation showed that the relative abundance of Bacteroides was negatively correlated with the mRNA expression level of NLRP3 (P < 0.05) and the relative abundance of Ruminococcus_torques_group was positively correlated with the mRNA expression level of NLRP3 (P < 0.05). linear discriminant analysis (LDA) effect size (LEfSe) results (LDA > 4) showed that the relative abundance of Bacteroides was dramatically higher (P < 0.05) in the 12L:12D group, whereas the relative abundance of Ruminococcus_torques_group was noticeably higher (P < 0.05) in the 23L:1D group. By the comprehensive analysis of the gut microbiota, the interaction of gut microbiota (Bacteroides and Ruminococcus_torques_group) and NLRP3 inflammasome may contribute to the intestinal injury under the condition of extended photoperiod.

Lactobacillus acidophilus and Bacillus subtilis significantly change the growth performance, serum immunity and cecal microbiota of Cherry Valley ducks during the fattening period

This study explored the effects of a Bacillus subtilis and Lactobacillus acidophilus mixture containing the co-fermented products of the two probiotics on growth performance, serum immunity and cecal microbiota of Cherry Valley ducks. This study included 480 one-day-old Cherry Valley ducks divided into four feeding groups: basal diet (control group) and basal diet supplemented with 300, 500, or 700 mg/kg of the probiotic powder; the ducks were raised for 42 days. Compared with the control group, body weight on day 42 and the average daily gain on days 15-42 significantly increased (p < 0.05), and the feed conversion rate significantly decreased (p < 0.05) in the experimental groups. Furthermore, the serum immunoglobulin (Ig) A, IgG, IgM, and interleukin (IL)-4 levels increased significantly (p < 0.05), and IL-1β, IL-2, and tumor necrosis factor-α decreased significantly (p < 0.05) in the experimental groups. Finally, Sellimonas, Prevotellaceae NK3B31 group, Lachnospiraceae NK4A136 group and Butyricoccus played an important role in the cecal microbiota of the experimental group. Thus, the probiotic powder has impacts on the growth performance, serum immunity and cecal microbiota of Cherry Valley Ducks.

Comparison of yeast-derived commercial feed additives on Salmonella Enteritidis survival and microbiota populations in rooster cecal in vitro incubations

Yeast-derived products have become more of an interest in the poultry industry as of late because of their use in modulating the gastrointestinal tract (GIT) microbiome to both improve production parameters and prevent infection. This study aimed to evaluate the effects of various yeast-derived products on Salmonella enterica inoculation in un in vitro rooster cecal incubations and associated effects on the cecal microbiome. Cecal contents were obtained from 53-wk old White Leghorn H & N Nick Chick roosters (n = 3) fed a wheat-based, commercial-type basal diet. Cecal contents were diluted 1:3000 in anaerobic dilution solution (ADS) in an anaerobic chamber, with 20 mL aliquoted to each serum bottle. There were three controls (n = 3): basal diet only, diluted cecal contents only, and basal diet and diluted cecal contents; and five treatments containing the basal diet and diluted cecal contents (n = 3): Citristim® (ADM), ImmunoWall® (ICC), Maxi-Gen Plus® (CBS Bio Platforms), Hilyses® (ICC), and Original XPC® (Diamond V). All treatments were applied at a rate of 2.5 kg/tonne or less. All groups were inoculated with a nalidixic acid-resistant strain of Salmonella Enteritidis at 10^7 CFU/mL and incubated at 37 deg C. Samples were collected at 0, 24, and 48 h for S. Enteritidis enumeration and 16S rDNA microbial sequencing. Salmonella data were log-transformed and analyzed in a two-way ANOVA with means separated using Tukey's HSD (P≤0.05). Genomic DNA was extracted, and resulting libraries were prepared and sequenced using an Illumina MiSeq. Sequencing data were analyzed in QIIME2 (2021.4) with diversity metrics (alpha and beta), and an analysis of the composition of microbiomes (ANCOM) was performed. Main effects were considered significant at P≤0.05, with pairwise differences considered significant at Q≤0.05. There was an interaction of treatment and time on the enumeration of Salmonella where treatments of Citristim, Immunowall, Hilyses, and XPC reduced Salmonella by 1 log CFU/mL compared to the controls. At 48 h, each yeast product treatment reduced Salmonella by 3 log CFU/mL compared to the controls. There was no main effect of treatment on the alpha diversity metrics, richness, or evenness (P > 0.05). Treatment affected the beta diversity, abundance, and phylogenetic differences, but there were no pairwise differences (P>0.05, Q>0.05). Using ANCOM at the genus level, the taxa Synergistes, Alloprevotella, Sutterella, and Megasphaera abundance were significantly different (W = 154,147,145,140, respectively). These results demonstrate the potential of these yeast-derived products to reduce foodborne pathogens, such as Salmonella Enteriditis, in vitro, without negatively disrupting the cecal microbiome.

The temporal fluctuations and development of faecal microbiota in commercial layer flocks

The microbiota of the gastrointestinal tract influences gut health, which in turn strongly impacts the general health and productivity of laying hens. It is essential to characterise the composition and temporal development of the gut microbiota in healthy layers raised under different management systems, to understand the variations in typical healthy microbiota structure, so that deviations from this might be recognised and correlated with production and health issues when they arise. The present investigation aimed to study the temporal development and phylogenetic composition of the gut microbiota of four commercially raised layer flocks from hatch to end of the production cycle. Non-intrusive faecal sampling was undertaken as a proxy to represent the gut microbiota. Sequencing of 16S rRNA gene amplicons was used to characterise the microbiota. Beta diversity analysis indicated that each faecal microbiota was different across the four flocks and had subtly different temporal development patterns. Despite these inter-flock differences, common patterns of microbiota development were identified. Firmicutes and Proteobacteria were dominant at an early age in all flocks. The microbiota developed gradually during the rearing phase; richness and diversity increased after 42 d of age and then underwent significant changes in composition after the shift to the production farms, with Bacteroidota becoming more dominant in older birds. By developing a more profound knowledge of normal microbiota development in layers, opportunities to harness the microbiota to aid in the management of layer gut health and productivity may be more clearly seen and realised.

Canaries' Microbiota: The Gut Bacterial Communities along One Female Reproductive Cycle

Investigations of bacterial communities are on the rise both in human and veterinary medicine. Their role in health maintenance and pathogenic mechanisms is in the limelight of infectious, metabolic, and cancer research. Among the most considered, gut bacterial communities take the cake. Their part in animals was assessed mainly to improve animal production, public health, and pet management. In this regard, canaries deserve attention, being a popular pet and source of economic income for bird-keepers, for whom breeding represents a pivotal point. Thus, the present work aimed to follow gut bacterial communities' evolution along on whole reproductive cycle of 12 healthy female canaries. Feces were collected during parental care, molting, and resting phase, and submitted for 16S rRNA sequencing. Data were analyzed and a substantial presence of Lactobacillus aviarius along all the phases, and a relevant shift of microbiota during molting and rest due to an abrupt decrease of the Vermiphilaceae family were detected. Although the meaning of such change is not clear, future research may highlight unforeseen scenarios. Moreover, Lactobacillus aviarius may be deemed for normal bacteria flora restoration in debilitated birds, perhaps improving their health and productivity.

Ameliorative avian gut environment and bird productivity through the application of safe antibiotics alternatives: a comprehensive review

The avian digestive tract is an important system for converting ingested food into the nutrients their bodies need for maintenance, growth, and reproduction (meat, table eggs, and fertile eggs). Therefore, preserving digestive system integrity is crucial to bird health and productivity. As an alternative to antibiotics, the world has recently turned to the use of natural products to enhance avian development, intestinal health, and production. Therefore, the primary goal of this review is to explain the various characteristics of the avian digestive tract and how to enhance its performance with natural, safe feed additives such as exogenous enzymes, organic acids, photogenic products, amino acids, prebiotics, probiotics, synbiotics, and herbal extracts. In conclusion, the composition of the gut microbiome can be influenced by a number of circumstances, and this has important consequences for the health and productivity of birds. To better understand the connection between pathogens, the variety of therapies available, and the microbiome of the gut, additional research needs to be carried out.

Amplicon-based metagenomic association analysis of gut microbiota in relation to egg-laying period and breeds of hens

BACKGROUND

The gut microbiota plays an essential role in maintaining gut homeostasis and improving performance, with the composition of microbial communities visibly differing across different laying stages in hens and significantly correlating with egg production. To gain further insights into the association between microbial community characteristics and laying periods in Hy-Line variety brown and Isa brown laying hens, we conducted a 16S rRNA amplicon sequencing survey.

RESULTS

Our result revealed the diversity of bacteria in the early laying period was commonly higher than peak, and in Hy-Line variety brown laying hens were generally higher than Isa brown. Principal coordinate analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA) revealed that the structure and composition of the gut microbiota of laying hens exhibited significant differences among different groups. Phylum Firmicutes, Bacteroidota, Proteobacteria, and Fusobacteriota were found that dominant in the host's feces. Therein, the abundance of Fusobacteriota was higher in the peak period than in the early period, while the abundance of Cyanobacteria in the early period was higher in two breeds of hens. Furthermore, random forest based on machine learning showed that there were several distinctly abundant genera, which can be used as potential biomarkers to differentiate the different groups of laying periods and breeds. In addition, the prediction of biological function indicated the existing discrepancy in microbial function among the microbiota of four groups.

CONCLUSIONS

Our findings offer new insights into the bacterial diversity and intestinal flora composition of different strains of laying hens during various laying periods, contributing significantly to the improvement of production performance and the prevention of chicken diseases.

Microbiome of Ceca from Broiler Chicken Vaccinated or Not against Coccidiosis and Fed Berry Pomaces

American cranberry (Vaccinium macrocarpon) and lowbush/wild blueberry (V. angustifolium) pomace are polyphenol-rich products having potentially beneficial effects in broiler chickens. This study investigated the cecal microbiome of broiler-vaccinated or non-vaccinated birds against coccidiosis. Birds in each of the two groups (vaccinated or non-vaccinated) were fed a basal non-supplemented diet (NC), a basal diet supplemented with bacitracin (BAC), American cranberry (CP), and lowbush blueberry (BP) pomace alone or in combination (CP + BP). At 21 days of age, cecal DNA samples were extracted and analyzed using both whole-metagenome shotgun sequencing and targeted-resistome sequencing approaches. Ceca from vaccinated birds showed a lower abundance of Lactobacillus and a higher abundance of Escherichia coli than non-vaccinated birds (p < 0.05). The highest and lowest abundance of L. crispatus and E. coli, respectively, were observed in birds fed CP, BP, and CP + BP compared to those from NC or BAC treatments (p < 0.05). Coccidiosis vaccination affected the abundance of virulence genes (VGs) related to adherence, flagella, iron utilization, and secretion system. Toxin-related genes were observed in vaccinated birds (p < 0.05) in general, with less prevalence in birds fed CP, BP, and CP + BP than NC and BAC (p < 0.05). More than 75 antimicrobial resistance genes (ARGs) detected by the shotgun metagenomics sequencing were impacted by vaccination. Ceca from birds fed CP, BP, and CP + BP showed the lowest (p < 0.05) abundances of ARGs related to multi-drug efflux pumps, modifying/hydrolyzing enzyme and target-mediated mutation, when compared to ceca from birds fed BAC. Targeted metagenomics showed that resistome from BP treatment was distant to other groups for antimicrobials, such as aminoglycosides (p < 0.05). Significant differences in the richness were observed between the vaccinated and non-vaccinated groups for aminoglycosides, β-lactams, lincosamides, and trimethoprim resistance genes (p < 0.05). Overall, this study demonstrated that dietary berry pomaces and coccidiosis vaccination significantly impacted cecal microbiota, virulome, resistome, and metabolic pathways in broiler chickens.

Feeding broiler chickens with arginine above recommended levels: effects on growth performance, metabolism, and intestinal microbiota

BACKGROUND

Arginine is an essential amino acid for chickens and feeding diets with arginine beyond the recommended levels has been shown to influence the growth performance of broiler chickens in a positive way. Nonetheless, further research is required to understand how arginine supplementation above the widely adopted dosages affects metabolism and intestinal health of broilers. Therefore, this study was designed to assess the effects of arginine supplementation (i.e., total arginine to total lysine ratio of 1.20 instead of 1.06-1.08 recommended by the breeding company) on growth performance of broiler chickens and to explore its impacts on the hepatic and blood metabolic profiles, as well as on the intestinal microbiota. For this purpose, 630 one-day-old male Ross 308 broiler chicks were assigned to 2 treatments (7 replicates each) fed a control diet or a crystalline L-arginine-supplemented diet for 49 d.

RESULTS

Compared to control birds, those supplemented with arginine performed significantly better exhibiting greater final body weight at D49 (3778 vs. 3937 g; P < 0.001), higher growth rate (76.15 vs. 79.46 g of body weight gained daily; P < 0.001), and lower cumulative feed conversion ratio (1.808 vs. 1.732; P < 0.05). Plasma concentrations of arginine, betaine, histidine, and creatine were greater in supplemented birds than in their control counterparts, as were those of creatine, leucine and other essential amino acids at the hepatic level. In contrast, leucine concentration was lower in the caecal content of supplemented birds. Reduced alpha diversity and relative abundance of Firmicutes and Proteobacteria (specifically Escherichia coli), as well as increased abundance of Bacteroidetes and Lactobacillus salivarius were found in the caecal content of supplemented birds.

CONCLUSIONS

The improvement in growth performance corroborates the advantages of supplementing arginine in broiler nutrition. It can be hypothesized that the performance enhancement found in this study is associated with the increased availability of arginine, betaine, histidine, and creatine in plasma and the liver, as well as to the ability of extra dietary arginine to potentially ameliorate intestinal conditions and microbiota of supplemented birds. However, the latter promising property, along with other research questions raised by this study, deserve further investigations.

Effects of Lactobacillus plantarum and its Fermentation Products on Growth Performance, Immune Function, Intestinal pH and Cecal Microorganisms of Lingnan Yellow Chicken

The present research was conducted to investigate the effects of dietary supplementation of Lactobacillus plantarum and its fermentation products on growth performance, specific immune function, intestinal pH, and cecal microorganisms in yellow-feather broilers. A total of 1,200 yellow-feather broilers of similar weight and good health condition at 1 d of age were selected and randomly divided into 5 groups. The CK group was fed the basal diet, and the experimental group (I, II, III, IV) were supplemented with 0.1, 0.15% L. plantarum and 3, 4% L. plantarum fermentation products. The results showed that each treatment could improve the growth performance (P < 0.05) and feed conversion rate of yellow-feather broilers. Besides, the pH value of the gastrointestinal tract of yellow-feather broilers (P < 0.05) was significantly reduced through the use of L. plantarum and its fermentation products as additives, which also facilitated the animals to regulate the balance of cecal microorganisms. The immune function assay showed that the bursal index (P < 0.05), spleen index (P < 0.05), and the content of serum immunoglobulins IgA and IgG (P < 0.05) were significantly increased in yellow-finned broilers aged 1 to 21 d by supplementing the diet with L. plantarum. In conclusion, adding L. plantarum or its fermentation products to the diet can improve the growth performance of yellow-feather broilers, and the direct addition of L. plantarum is better than adding fermentation products.

Week-Old Chicks with High Bacteroides Abundance Have Increased Short-Chain Fatty Acids and Reduced Markers of Gut Inflammation

As important commensals in the chicken intestine, Bacteroides are essential complex carbohydrate degraders, and short-chain fatty acid (SCFA) producers that are highly adapted to the distal gut. Previous studies have shown large variation in Bacteroides abundance in young chickens. However, limited information is available regarding how this variation affects the gut microbiome and host immunity. To investigate how elevated or depleted Bacteroides levels affect gut microbial functional capacity and impact host response, we sampled 7-day-old broiler chickens from 14 commercial production flocks. Week-old broiler chickens were screened and birds with low Bacteroides (LB) and high Bacteroides (HB) abundance were identified via 16S rRNA gene amplicon sequencing and quantitative PCR (qPCR) assays. Cecal microbial functionality and SCFA concentration of chickens with distinct cecal Bacteroides abundance were profiled by shotgun metagenomic sequencing and gas chromatography, respectively. The intestinal immune responses of LB and HB chickens were assessed via reverse transcription qPCR. Results showed that the gut microbiota of the LB group had increased abundance of lactic acid bacteria pyruvate fermentation pathway, whereas complex polysaccharide degradation and SCFA production pathways were enriched in the HB group (P < 0.05), which was supported by increased SCFA concentrations in the ceca of HB chickens (P < 0.05). HB chickens also showed decreased expression of interleukin-1β and increased expression of interleukin-10 and tight-junction protein claudin-1 (P < 0.05). Overall, the results indicated that elevated Bacteroides may benefit the 7-day broiler gut and that further work should be done to confirm the causal role of Bacteroides in the observed positive outcomes. IMPORTANCE To date, limited information is available comparing distinct Bacteroides compositions in the chicken gut microbial communities, particularly in the context of microbial functional capacities and host responses. This study showed that possessing a microbiome with elevated Bacteroides in early life may confer beneficial effects to the chicken host, particularly in improving SCFA production and gut health. This study is among the first metagenomic studies focusing on the early life chicken gut microbiota structure, microbial functionality, and host immune responses. We believe that it will offer insights to future studies on broiler gut microbial population and their effects on host health.

Association of gut microbiota and SCFAs with finishing weight of Diannan small ear pigs

Finishing weight is a key economic trait in the domestic pig industry. Evidence has linked the gut microbiota and SCFAs to health and production performance in pigs. Nevertheless, for Diannan small ear (DSE) pigs, a specific pig breed in China, the potential effect of gut microbiota and SCFAs on their finishing weight remains unclear. Herein, based on the data of the 16S ribosomal RNA gene and metagenomic sequencing analysis, we found that 13 OTUs could be potential biomarkers and 19 microbial species were associated with finishing weight. Among these, carbohydrate-decomposing bacteria of the families Streptococcaceae, Lactobacillaceae, and Prevotellaceae were positively related to finishing weight, whereas the microbial taxa associated with intestinal inflammation and damage exhibited opposite effects. In addition, interactions of these microbial species were found to be linked with finishing weight for the first time. Gut microbial functional annotation analysis indicated that CAZymes, such as glucosidase and glucanase could significantly affect finishing weight, given their roles in increasing nutrient absorption efficiency. Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthologies (KOs) and KEGG pathways analysis indicated that glycolysis/gluconeogenesis, phosphotransferase system (PTS), secondary bile acid biosynthesis, ABC transporters, sulfur metabolism, and one carbon pool by folate could act as key factors in regulating finishing weight. Additionally, SCFA levels, especially acetate and butyrate, had pivotal impacts on finishing weight. Finishing weight-associated species Prevotella sp. RS2, Ruminococcus sp. AF31-14BH and Lactobacillus pontis showed positive associations with butyrate concentration, and Paraprevotella xylaniphila and Bacteroides sp. OF04-15BH were positively related to acetate level. Taken together, our study provides essential knowledge for manipulating gut microbiomes to improve finishing weight. The underlying mechanisms of how gut microbiome and SCFAs modulate pigs' finishing weight required further elucidation.

Effects of Dietary Isoleucine Supplementation on the Production Performance, Health Status and Cecal Microbiota of Arbor Acre Broiler Chickens

A total of 24,000 healthy 1-day-old Arbor Acres broilers with similar initial weights were used in this study and fed a basal diet supplemented with 0, 400 and 800 mg/kg isoleucine (Ile), denoted CON, ILE400 and ILE800, respectively. Results revealed that the final body weight, average daily weight gain, and eviscerated carcass rate, of broiler chickens in the ILE400 group were significantly higher than in other groups (p < 0.05). In addition, the ILE400 and ILE800 groups had a lower feed conversion rate and a higher survival rate and breast muscle rate (p < 0.05), while the abdominal fat rate was significantly lower than the CON group (p < 0.05). There were significantly lower serum concentrations of UREA, glucose (GLU) and total cholesterol (TCHO) in the ILE400 and ILE800 groups than in the CON group (p < 0.05); glutathione peroxidase (GSH-Px) activity was significantly higher in the ILE400 group than in the other groups, and tumor necrosis factor-alpha (TNF-α) concentration was considerably lower than in other groups (p < 0.05). Moreover, interleukin (IL)-10 concentration in the ILE800 group was significantly higher than in the other groups (p < 0.05). The ILE400 group significantly down-regulated the mRNA expressions of fatty-acid synthase (FASN) and solid alcohol regulatory element binding protein 1c (SREBP1c), and significantly up-regulated the mRNA expressions of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), lipoprotein lipase (LPL) and sirtuin1 (Sirt1) (p < 0.05). The ILE400 group had significantly higher intestinal villus height than the CON and ILE800 groups, while the ILE800 group had significantly lower intestinal villus height/crypt depth (p < 0.05). Furthermore, high-throughput sequencing showed that the Shannon index, and Verrucomicrobiota, Colidextribacter and Bacteroides abundances were significantly higher in the ILE400 group than in the CON group (p < 0.05). Interestingly, the ILE800 group reduced the Simpson index, phylum Firmicutes and Bacteroidota abundances (including genera Colidextribacter, Butyricicoccus, [Ruminococcus]_torques_group, Bacteroides, Alistipes, Barnesiella and Butyricimonas), and increased Proteobacteria and Cyanobacteria (including genera Dyella, Devosia, unidentified_Chloroplast and Hyphomicrobium) (p < 0.05). Overall, our study showed that adding 400 mg/kg Ile to the diet (diets total Ile levels at 1.01%, 0.90% and 0.87% during the starter, grower and finisher phases, respectively) increased production performance and improved the health status in broiler chickens.

Tannins-Based Extracts: Effects on Gut Chicken Spontaneous Contractility

The impossibility of using drugs for the health of farm animals leads to the search for alternative strategies with two purposes: to maintain animal health and safeguard human health. In this perspective, tannins have shown great promises. These phytocomplexes obtained from natural matrices with multiple health properties may be used as a feed supplement in chicken farms. In this work, we studied two tannin-based extracts (from Castanea sativa Mill. wood and from Schinopsis balansae Engl. Quebracho Colorado hardwood) with different chemical compositions on the spontaneous contractility on the isolated intestinal tissues of healthy chicken. The results showed that the chemical composition of the two phytocomplexes influenced the spontaneous intestinal contractility in different ways by regulating the tone and consequent progression of the food bolus. The chemical analysis of the two extracts revealed that Castanea sativa Mill. wood mainly contains hydrolysable tannins, while Schinopsis balansae Engl. hardwood mainly contains condensed tannins. The two phytocomplexes showed different effects towards gastrointestinal smooth muscle contractility, with Castanea sativa Mill. wood providing a better activity profile than Schinopsis balansae Engl. hardwood.

Effects of Dietary Supplementation of Lactobacillus acidophilus on Blood Parameters and Gut Health of Rabbits

This study aimed to evaluate the effects of Lactobacillus acidophilus D2/CSL (L-1 × 109 cfu/kg feed/day) on biochemical parameters, faecal score (FS), cecal pH, gut morphometry, microbiota and cecal short-chain fatty acid (SCFAs) in rabbits. Three zootechnical trials were performed and in each trial 30 rabbits were allotted to two groups; a probiotic group (L) and a control group (C). At slaughter (day 45), samples of blood, duodenum, jejunum, ileum, liver and spleen were collected and submitted to histomorphometric analyses. Blood biochemical analyses, cecal microbiota and SCFAs determination were also performed. In trial 1 and 3, L. acidophilus D2/CSL did not affect productive parameters (p > 0.05). However, L group of trial 1 showed a lower morbidity and mortality compared to the control. In trial 2, C group showed a higher daily feed intake (p = 0.018) and a positive statistical tendency for live weight and average daily gain (p = 0.068). On the contrary, albumin was higher and ALFA-1 globulin was lower in the C group compared to L (p < 0.05). In all the trials, FS, cecal pH, histomorphometry, microbiota and SCFAs were unaffected. In conclusion, L. acidophilus D2/CSL did not impair growth performances, gut and rabbit’s health, reducing morbidity and mortality.

Gut Microbiome Studies in Livestock: Achievements, Challenges, and Perspectives

The variety and makeup of the gut microbiome are frequently regarded as the primary determinants of health and production performances in domestic animals. High-throughput DNA/RNA sequencing techniques (NGS) have recently gained popularity and permitted previously unheard-of advancements in the study of gut microbiota, particularly for determining the taxonomic composition of such complex communities. Here, we summarize the existing body of knowledge on livestock gut microbiome, discuss the state-of-the-art in sequencing techniques, and offer predictions for next research. We found that the enormous volumes of available data are biased toward a small number of globally distributed and carefully chosen varieties, while local breeds (or populations) are frequently overlooked despite their demonstrated resistance to harsh environmental circumstances. Furthermore, the bulk of this research has mostly focused on bacteria, whereas other microbial components such as protists, fungi, and viruses have received far less attention. The majority of these data were gathered utilizing traditional metabarcoding techniques that taxonomically identify the gut microbiota by analyzing small portions of their genome (less than 1000 base pairs). However, to extend the coverage of microbial genomes for a more precise and thorough characterization of microbial communities, a variety of increasingly practical and economical shotgun techniques are currently available.

Gut microbiota dysbiosis exaggerates ammonia-induced tracheal injury Via TLR4 signaling pathway

Ammonia is a toxic air pollutant that causes severe respiratory tract injury in animals and humans. Gut microbiota dysbiosis has been found to be involved in the development of respiratory tract injury induced by air pollutants, however, the specific mechanism requires investigation. Here, we found that, inhaled ammonia induced tracheal injury by reducing expression of claudin-1, increasing expression of muc5ac, TLR4, MyD88, NF-κB and cytokines (TNF-α, IL-1β, IL-6 and IL-10), and also altering tracheal microbiota composition. Spearman correlation analysis indicated that gut microbiota dysbiosis positively correlated with TLR4 level in the trachea. Antibiotic depletion intestinal microbiota treatment reduced the severity of ammonia-induced tracheal injury via TLR4 signaling pathway. Microbiota transplantation induced the tracheal injury via TLR4 signaling pathway even without the ammonia exposure. These results indicate that gut microbiota dysbiosis exaggerates ammonia-induced tracheal injury via TLR4 signaling pathway. In addition, the [Ruminococcus]_torques_group, Faecalibacterium, unclassified_f_Lachnospiraceae may be the key gut microbiota contributing to the alterations of tracheal microbiota composition.

The active core microbiota of two high-yielding laying hen breeds fed with different levels of calcium and phosphorus

The nutrient availability and supplementation of dietary phosphorus (P) and calcium (Ca) in avian feed, especially in laying hens, plays a vital role in phytase degradation and mineral utilization during the laying phase. The required concentration of P and Ca peaks during the laying phase, and the direct interaction between Ca and P concentration shrinks the availability of both supplements in the feed. Our goal was to characterize the active microbiota of the entire gastrointestinal tract (GIT) (crop, gizzard, duodenum, ileum, caeca), including digesta- and mucosa-associated communities of two contrasting high-yielding breeds of laying hens (Lohmann Brown Classic, LB; Lohmann LSL-Classic, LSL) under different P and Ca supplementation levels. Statistical significances were observed for breed, GIT section, Ca, and the interaction of GIT section x breed, P x Ca, Ca x breed and P x Ca x breed (p &lt; 0.05). A core microbiota of five species was detected in more than 97% of all samples. They were represented by an uncl. Lactobacillus (average relative abundance (av. abu.) 12.1%), Lactobacillus helveticus (av. abu. 10.8%), Megamonas funiformis (av. abu. 6.8%), Ligilactobacillus salivarius (av. abu. 4.5%), and an uncl. Fusicatenibacter (av. abu. 1.1%). Our findings indicated that Ca and P supplementation levels 20% below the recommendation have a minor effect on the microbiota compared to the strong impact of the bird’s genetic background. Moreover, a core active microbiota across the GIT of two high-yielding laying hen breeds was revealed for the first time.

Acids produced by lactobacilli inhibit the growth of commensal Lachnospiraceae and S24-7 bacteria

The Lactobacillaceae are an intensively studied family of bacteria widely used in fermented food and probiotics, and many are native to the gut and vaginal microbiota of humans and other animals. Various studies have shown that specific Lactobacillaceae species produce metabolites that can inhibit the colonization of fungal and bacterial pathogens, but less is known about how Lactobacillaceae affect individual bacterial species in the endogenous animal microbiota. Here, we show that numerous Lactobacillaceae species inhibit the growth of the Lachnospiraceae family and the S24-7 group, two dominant clades of bacteria within the gut. We demonstrate that inhibitory activity is a property common to homofermentative Lactobacillaceae species, but not to species that use heterofermentative metabolism. We observe that homofermentative Lactobacillaceae species robustly acidify their environment, and that acidification alone is sufficient to inhibit growth of Lachnospiraceae and S24-7 growth, but not related species from the Clostridiales or Bacteroidales orders. This study represents one of the first in-depth explorations of the dynamic between Lactobacillaceae species and commensal intestinal bacteria, and contributes valuable insight toward deconvoluting their interactions within the gut microbial ecosystem.

A multi-omics approach to elucidate the mechanisms of action of a dietary muramidase administered to broiler chickens

A novel dietary muramidase has been shown to have positive effects on broiler chickens. However, very little is known about its mechanisms of action. The present multi-omics investigation sought to address this knowledge gap. A total of 2,340 day-old male broilers were assigned to 3 groups (12 replicates each) fed, from 0 to 42 d, a basal diet (control group—CON) or the basal diet supplemented with muramidase at 25,000 (low-dose group—MUL) or 45,000 LSU(F)/kg feed (high-dose group—MUH). MUH significantly outperformed CON in terms of cumulative feed intake (4,798 vs 4,705 g), body weight (2,906 vs 2,775 g), and feed conversion ratio (1.686 vs 1.729), while MUL exhibited intermediate performance. At caecal level, MUH showed the lowest alpha diversity, a significantly different beta diversity, a reduction in Firmicutes, and a rise in Bacteroidetes, especially compared with MUL. MUH also exhibited a considerable decrease in Clostridiaceae and an overrepresentation of Bacteroidaceae and Lactobacillaceae. At blood level, MUH had lower hypoxanthine—probably due to its drop at caecal level—histidine, and uracil, while greater pyruvate, 2-oxoglutarate, and glucose. This study sheds light on the mode of action of this muramidase and lays the groundwork for future investigations on its effects on the intestinal ecosystem and systemic metabolism of broiler chickens.

Pilot Study on Poultry Meat from Antibiotic Free and Conventional Farms: Can Metagenomics Detect Any Difference?

Antibiotic free farms are increasing in the poultry sector in order to address new EU regulations and consumer concerns. In this pilot study, we investigated whether the efforts of raising chickens without the use antibiotics make any difference in the microbiome of poultry meat eaten by consumers. To this aim we compared the microbiomes characterizing caeca and the corresponding carcasses of two groups of chickens reared, one reared on a conventional farm and one on an antibiotic-free intensive farm. The results showed a clear separation between the taxonomic, functional and antibiotic resistant genes in the caeca of the birds reared on the conventional and antibiotic free farm. However, that separation was completely lost on carcasses belonging to the two groups. The antibiotic-free production resulted in statistically significant lower antimicrobial resistance load in the caeca in comparison to the conventional production. Moreover, the antimicrobial resistance load on carcasses was much higher than in the caeca, without any significant difference between carcasses coming from the two types of farms. All in all, the results of this research highlighted the need to reduce sources of microbial contamination and antimicrobial resistance not only at the farm level but also at the post-harvest one.

<i>Bacillus subtilis-</i>Fermented Products Ameliorate the Growth Performance, Alleviate Intestinal Inflammatory Gene Expression, and Modulate Cecal Microbiota Community in Broilers during the Starter Phase under Dextran Sulfate Sodium Challenge

The aim of this study was to evaluate the effects of B. subtilis-fermented products (BSFP) on growth performance, intestinal inflammatory gene expression, and cecal microbiota community in broilers challenged with dextran sulfate sodium (DSS) in a 14-day experiment. A total of 32, 1-day-old male broiler chickens (Ross 308), were randomly divided into four groups of eight birds per group and reared individually (n=8). The treatments consisted of a control diet without supplementation and DSS challenge, control diet plus 1.5% DSS, control diet plus 1 g/kg BSFP in combination with 1.5% DSS, and control diet plus 3 g/kg of BSFP in combination with 1.5% DSS. The results showed that BSFP supplementation (1 and 3 g/kg) partially improved body weight and average daily gain in broilers under DSS challenge. Relative to DSS treatment alone, BSFP supplementation dose-dependently increased the body weight of broilers at 7 days of age, with the average daily gain being at 1 to 7 days of age. BSFP supplementation (1 and 3 g/kg) alleviated intestinal inflammatory gene expression in broilers under DSS challenge. The richness and evenness of bacterial species in cecal digesta increased in a dose-dependent manner in the groups treated with BSFP (1 and 3 g/kg) in combination with DSS challenge, compared with the control group. Unweighted principal coordinate analysis indicated distinct clusters separating the group treated with 3 g/kg of BSFP in combination with DSS challenge from the other three groups. The abundance of short-chain fatty acid-producing bacteria (genus Ruminococcaceae_unclassified) increased and that of mucindegrading bacteria (genus Ruminococcus torques group) decreased in the cecal digesta of broilers fed 3 g/kg of BSFP, compared with the control group. In conclusion, BSFP supplementation dose-dependently improved growth performance, reduced gut inflammation, and regulated the cecal microbiota of broilers exposed to DSS challenge during the starter phase.

Ammonia exposure induced intestinal inflammation injury mediated by intestinal microbiota in broiler chickens via TLR4/TNF-α signaling pathway

Ammonia is a known environmental pollutant that causes injury to the intestine. Growing evidence suggests that intestinal microbiota dysbiosis involves in the development of intestinal injury under environmental pollution. However, the specific mechanism remains unexplored. To do this, broiler chicken ileal exposed to ammonia was selected as the research object. Further, antibiotic depletion of intestinal microbiota and flora transplantation were used to clarify the role of intestinal microbiota in the intestinal injury. Histopathological examination indicated inhaled ammonia caused intestinal injury. Then we observed a decrease in intestinal muc-2, claudin-1, IL-6, IL-10 in ammonia inhalation, as opposed to the control group, associated with a significant increase in TLR4, MyD88, NF-κB, TNF-α, IL-1β, caspase3. Moreover, there was a significant increase of Streptococcus, Escherichia-Shigella, Faecalibacterium, [Ruminococcus]_torques_group, Ruminococcaceae_UCG-014, unclassified_f_Lachnospiraceae, Rothia, unclassified_f_Ruminococcaceae in the inhaled ammonia exposure. Correlation analysis suggested that the altered genera were positively correlated with the expression of TLR4 and TNF-α. Moreover, transferring intestinal microbiota from ammonia exposure broiler into healthy broiler caused intestinal injury and increased TLR4 and TNF-α concentrations in recipient broiler. Furthermore, antibiotic depletion of intestinal microbiota attenuated ammonia-caused intestinal injury and reduced TLR4 and TNF-α productions. In summary, TLR4/TNF-α signaling pathway was an important regulated mechanism involved in the intestinal injury mediated by intestinal microbiota dysbiosis under inhaled ammonia.

Lactic Acid Bacteria - A Promising Tool for Controlling Chicken Campylobacter Infection

Since 2005, campylobacteriosis has been the most common zoonotic disease in Europe. The main reservoir of pathogenic Campylobacter strains is broilers, which makes raw and undercooked poultry meat two major sources of disease. Infection in chicken flocks is most often asymptomatic, despite a high level of colonization reaching 106-109cfu/g in animal ceca. It is widely believed that controlling the level of colonization of the birds' digestive tract by pathogenic strains is a good way to increase food safety. Many treatments have been proposed to combat or at least reduce the level of colonization in animals reservoirs: probiotics, bacteriophages, vaccines, and anti-Campylobacter bacteriocins. This review focuses on the effects of Campylobacter infection on the chicken microbiome and colonization control strategies using probiotics (mostly lactic acid bacteria, LAB), which are live microorganisms included in the diet of animals as feed additives or supplements. Probiotics are not only an alternative to antibiotics, which were used for years as animal growth promoters, but they also constitute an effective protective barrier against excessive colonization of the digestive system by pathogenic bacteria, including Campylobacter. Moreover, one of the many beneficial functions of probiotics is the ability to manipulate the host's microbiota. Recently, there have also been some promising attempts to use lactic acid bacteria as a delivery system of oral vaccine against Campylobacter. Recombinant LAB strains induce primarily a mucosal immune response against foreign antigens, accompanied by at most a low-level immune response against carrier strains. Since the main barrier against the invasion of pathogens in the gastrointestinal tract is the intestinal mucosal membrane, the development of effective oral vaccines to protect animals against enteric infection is very reasonable.

Probiotics and gut health: linking gut homeostasis and poultry productivity

The use of probiotics in poultry production has increased rapidly, and this movement has been promoted by global events, such as the prohibition or decline in the use of antibiotic growth promotants in poultry feeds. There has been a persistent search for alternative feed additives, and probiotics have shown that they can restore the composition of the gut microbiota, and produce health benefits to the host, including improvements in performance. Probiotics have shown potential to increase productivity in poultry, especially in flocks challenged by stressors. However, the outcomes of probiotic use have not always been consistent. There is an increasing demand for well defined products that can be applied strategically, and currently, probiotic research is focusing on delineating their mechanisms of action in the gut that contribute to an improved efficacy. In particular, mechanisms involved in the maintenance and protection of intestinal barrier integrity and the role of the gut microbiota are being extensively investigated. It has been shown that probiotics modulate intestinal immune pathways both directly and through interactions with the gut microbiota. These interactions are key to maintaining gut homeostasis and function, and improving feed efficiency. Research has demonstrated that probiotics execute their effects through multiple mechanisms. The present review describes recent advances in probiotic use in poultry. It focuses on the current understanding of gut homeostasis and gut health in chickens, and how it can be assessed and improved through supplementation of poultry diets with probiotics in poultry diets. In particular, cellular and molecular mechanisms involved in the maintenance and protection of gut barrier structure and function are described. It also highlights important factors that influence probiotic efficacy and bird performance.

Effect of sodium butyrate on slaughter performance, serum indexes and intestinal barrier of rabbits

The purpose of this study was to investigate the effect of sodium butyrate on slaughter performance, serum indexes and the intestinal barrier in rabbits. Six hundred healthy weaned rabbits were randomly divided into three groups (5 replicates per group, 40 rabbits per replicate): control (fed a basal diet), sodium butyrate (fed a basal diet containing 0.5% sodium butyrate) and antibiotic (fed a basal diet containing 0.004% antibiotic). The trial lasted 35 days, including 7 days of pretesting and 28 days of formal testing. The results showed that dietary sodium butyrate supplementation increased the full-bore weight, the half-bore weight and the half-bore rate of rabbits. Meanwhile, the content of aspartate aminotransferase (AST) in serum was increased in rabbits fed the sodium butyrate diet. According to the intestinal barrier, after adding sodium butyrate to feed, the tight junction function of the rabbit intestine is enhanced, and the intestinal microbial composition is also improved. To sum up, after sodium butyrate was added to feed instead of antibiotics, slaughter performance was significantly enhanced, serum indexes were improved, and intestinal barrier function was also enhanced. Therefore, sodium butyrate can be added to feed as an additive and can replace antibiotics.

Temporal dynamics of gut microbiota in caged laying hens: a field observation from hatching to end of lay

Gut health has major implications for the general health of food-producing animals such as the layer birds used in the egg industry. In order to modulate gut microbiota for the benefit of gut health, an understanding of the dynamics and details of the development of gut microbiota is critical. The present study investigated the phylogenetic composition of the gut microbiota of a commercial layer flock raised in cages from hatch to the end of the production cycle. This study also aimed to understand the establishment and development of gut microbiota in layer chickens. Results showed that the faecal microbiota was dominated by phyla Firmicutes and Proteobacteria in the rearing phase, but Bacteroidetes in mid lay and late lay phase. The gut microbiota composition changed significantly during the transfer of the flock from the rearing to the production shed. The richness and diversity of gut microbiota increased after week 6 of the flocks age and stabilized in the mid and late lay phase. The overall dynamics of gut microbiota development was similar to that reported in earlier studies, but the phylogenetic composition at the phylum and family level was different. The production stage of the birds is one of the important factors in the development of gut microbiota. This study has contributed to a better understanding of baseline gut microbiota development over the complete life cycles in layer chickens and will help to develop strategies to improve the gut health. KEY POINTS: • Faecal microbiota of caged hens was dominated by phyla Firmicutes and Proteobacteria in the rearing phase. • The gut microbiota composition changed significantly during the transfer of the flock from the rearing to the production shed. • The richness and diversity of gut microbiota increased after week 6 of the flocks age and stabilized in the mid and late lay phase.

Effect of Fermented Products Produced by Bacillus licheniformis on the Growth Performance and Cecal Microbial Community of Broilers under Coccidial Challenge

This study investigated the effects of fermented products produced by Bacillus licheniformis (fermented products) on the growth performance and cecal microbial community in broilers exposed to coccidial challenge. A total of 108 one-day-old male broiler chicks (Ross 308) were randomly allotted to one of three treatments. Each treatment was distributed into six replicate cages with six birds each. The treatments consisted of a basal diet without treatment (NC), basal diet plus coccidial challenge (PC), and basal diet plus the coccidial challenge and 1 g/kg of fermented products (FP). The results indicated that FP increased the average daily gain of broilers at 21 to 35 days of age compared with the PC group (p < 0.05). The anti-coccidia index in the FP group was elevated compared with the PC group (p < 0.05). Principal coordinate analysis showed significant segregation in bacterial community composition in the cecal digesta among the groups. The genus Lactobacillus was more abundant in the cecal digesta of the FP group compared with the PC group (p < 0.05). There was a positive correlation between the abundance of the genus Lactobacillus in the cecal digesta and growth performance (body weight, average daily gain, and average feed intake). Furthermore, the abundance of the genus Lactobacillus in the cecal digesta was positively associated with the cecal short-chain fatty acid levels (formic acid, acetic acid, propionic acid, butyric acid, and isobutyric acid). These findings suggest that fermented products produced by B. licheniformis can ameliorate the average daily gain of broilers exposed to coccidial challenge. B. licheniformis-fermented product supplementation increases anti-coccidial activity and modulates gut microbiota composition by increasing beneficial microbes and decreasing harmful microbes in broilers under coccidial challenge.

Transcriptome Analysis Reveals the Genes Involved in Growth and Metabolism in Muscovy Ducks

Muscovy ducks are among the best meat ducks in the world. The objective of this study was to identify genes related to growth metabolism through transcriptome analysis of the ileal tissue of Muscovy ducks. Duck ileum samples with the highest (H group, n = 5) and lowest (L group, n = 5) body weight were selected from two hundred 70-day-old Muscovy ducks for transcriptome analysis by RNA sequencing. In the screening of differentially expressed genes (DEGs) between the H and L groups, a total of 602 DEGs with a fold change no less than 2 were identified, among which 285 were upregulated and 317 were downregulated. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that glutathione metabolism, pyrimidine metabolism, and protein digestion and absorption processes played a vital role in regulating growth and metabolism. The results showed that 7 genes related to growth and metabolism, namely, ANPEP, ENPEP, UPP1, SLC2A2, SLC6A19, NME4, and LOC106034733, were significantly expressed in group H, which was consistent with the phenotype results. The validation of these 7 genes using real-time quantitative PCR results indicated that the expression level of ENPEP was significantly different between the H and L groups (P < 0.05). This study provides a theoretical basis for exploring the influence of the ileum on growth and metabolism in ducks.

Cecal Microbiota Modulates Fat Deposition in Muscovy Ducks

Ducks with the same genetic background vary greatly in their adiposity phenotypes. The gut microbiota plays an essential role in host physiological development and metabolism including fat deposition. However, the association of the gut microbiota with the lipogenic phenotype of ducks remains unknown. In this study, we investigated the cecal microbiota of adult Muscovy ducks and the correlation of the cecal microbiota with fat phenotypes. A total of 200 Muscovy ducks were selected from a population of 5,000 Muscovy ducks to record their abdominal fat weight and collect their cecal contents after being slaughtered and defeathered. The cecal contents were subjective to DNA isolation and 16S rRNA gene sequencing. The results were sorted according to the percentage of abdominal fat and the top 20% (n = 40) and the bottom 20% (n = 40) were set as the high and low groups, respectively. Our results indicated that in the cecum of Muscovy ducks, Bacteroidetes, Firmicutes, and Fusobacteria were the predominant phyla while Bacteroides, Oscillospiraceae_uncultured, Parabacteroides, and Bacteroidales_norank were the top 4 dominant genera. Abdominal fat weight (18.57~138.10 g) and percentage of abdominal fat (1.02~27.12%) were significantly correlated (R² = 0.92, P < 0.001). Although the lipogenic phenotypes of ducks had a significant difference (P < 0.05), the α-diversities of the high and low groups were not significantly different (P > 0.05). Nevertheless, after random forest analysis, we identified two genera, Treponema and Ruminococcus_torques_group, that were significantly associated with fat deposition in Muscovy ducks. In addition, the abundances of Treponema and Ruminococcus_torques_group gave a significantly negative and positive association with abdominal fat weight, respectively (P < 0.05). Ducks with a low level of Treponema exhibited a tendency toward a high percentage of abdominal fat (P < 0.01), while the percentage of abdominal fat in ducks with high Ruminococcus_torques_group abundance tended to be higher than that in ducks with low Ruminococcus_torques_group abundance (P < 0.01). These findings could provide the basic data on the cecal microbiota in Muscovy ducks as well as a theoretical foundation to limit the fat deposition by modulating the gut microbiota in the duck industry.

Comparative efficacy of spray-dried plasma and bacitracin methylene disalicylate in reducing cecal colonization by Salmonella Enteritidis in broiler chickens

Spray-dried plasma (SDP) contains immunoglobulins and glycoproteins that possess antibacterial properties. Two floor-pen trials were conducted to determine the efficacy of dietary SDP and bacitracin methylene disalicylate (BMD) antibiotic in reducing intestinal colonization by Salmonella Enteritidis (SE) in broiler chickens. Experiment 1 was a 2-wk, 3 × 2 factorial design consisting of 6 treatments. Treatment CON consisted of chicks fed unmedicated corn-soybean meal (SBM) basal without SDP. Treatment BMD consisted of chicks given unmedicated corn-SBM basal into which BMD was added at 0.055g/kg diet. Treatment SDP consisted of chicks given unmedicated corn-SBM basal into which SDP was added at 30g/kg diet. Treatments CON-SE, BMD-SE, and SDP-SE consisted of chicks that were given diets similar to CON, BMD, and SDP, respectively, and were each inoculated with 7.46 × 10⁸ CFU SE /mL at 1 day of age. Experiment 2 was a 42-day trial that was similar to Experiment 1 in design, except that chicks were placed on fresh clean litter. On d 3, 7, 14, and 28 post-challenge (PC), ceca SE concentration was enumerated on xylose lysine tergitol-4 (XLT4) agar. Body weight gain (BWG) and feed conversion ratio (FCR) were also recorded. Results for d 3 showed that BMD- and SDP-fed chicks had similar (P > 0.05) cecal SE (3.39 log ₁₀ CFU / g and 3.58 log ₁₀ CFU / g, respectively), but these levels were lower (P < 0.05) than that of CON-fed chicks (5.68 log ₁₀ CFU / g). A similar trend was observed on d 7 and 14 PC. The BMD- and SDP-fed chicks also had higher BWG and FCR (P < 0.05) when compared with CON-fed chicks up to d 14. Thereafter, only BMD treatment sustained this growth-promoting effect till d 42 in SE-challenged birds. In conclusion, BMD and SDP showed similar efficacy in reducing cecal Salmonella and in mitigating consequent growth-depressing effect(s) in broiler chicks up to 2 wk of age.

Comparison between 16S rRNA and shotgun sequencing data for the taxonomic characterization of the gut microbiota

In this paper we compared taxonomic results obtained by metataxonomics (16S rRNA gene sequencing) and metagenomics (whole shotgun metagenomic sequencing) to investigate their reliability for bacteria profiling, studying the chicken gut as a model system. The experimental conditions included two compartments of gastrointestinal tracts and two sampling times. We compared the relative abundance distributions obtained with the two sequencing strategies and then tested their capability to distinguish the experimental conditions. The results showed that 16S rRNA gene sequencing detects only part of the gut microbiota community revealed by shotgun sequencing. Specifically, when a sufficient number of reads is available, Shotgun sequencing has more power to identify less abundant taxa than 16S sequencing. Finally, we showed that the less abundant genera detected only by shotgun sequencing are biologically meaningful, being able to discriminate between the experimental conditions as much as the more abundant genera detected by both sequencing strategies.

Comparison of intestinal permeability, morphology, and ileal microbial communities of commercial hens housed in conventional cages and cage-free housing systems

The gastrointestinal health of poultry can be impacted by a variety of factors including their environment. As egg production moves from conventional cage housing (CC) toward cage-free housing (CF), it is important to understand this impact on intestinal health. This study was conducted to determine if housing type impacted intestinal permeability, morphology, and microbial communities in commercial hens across housing systems. Hens were randomly selected from 2 rooms of CC (n = 25) and CF (n = 25) at a commercial facility. Birds were given fluorescein isothiocyanate dextran (FITC-D) by oral gavage to measure intestinal permeability. Jejunal and ileal samples were collected to evaluate villus height, crypt depth, and their ratio. Ileal contents were collected for bacterial DNA isolation and 16S rRNA gene sequencing. Serum FITC-D was similar between housing type (P = 0.709). Hens housed in the CF had increased jejunal villus height and crypt depth compared with hens from the CC (P < 0.002). Hens from the CC tended to have a greater villus height to crypt depth ratio in both the jejunum and ileum compared with the CF (P = 0.064; P = 0.091, respectively). Microbial community diversity measurements favored hens housed in the CC as ileal contents tended to have increased species richness (P = 0.059), had greater alpha diversity (P = 0.044), and had an increased number of over represented operational taxonomic units (46/64), including Romboutsia sp. (30.80%), Lactobacillus kitasatonis (17.16%), and Lactobacillus aviarius (11.15%). Correlations between microbial communities with intestinal traits identified significant association with the greatest number of correlations with FITC-D and ileal morphology. Many of these correlations identified microbial communities associated with expected traits; thus, providing limited functional data to microbial communities with limited information. The greater number of correlations of ileal morphology with ileal microbial communities suggesting local microbial communities contribute to the intestinal environment distant. In this limited study, several parameters favored hens from CC suggesting an advantage of this system for intestinal health. However, the lower intestinal health parameters observed in CF were not at levels to indicate detrimental effects.

Effect of humate supplementation to feed and/or litter on performance, intestinal viscosity, litter quality, and occurrence of footpad dermatitis in broilers fed barley-based diets

We investigated the effect of in-feed and/or in-litter supplemental humate against footpad dermatitis (FPD) in broilers fed diets based on barley. Three hundred and sixty 1-day-old Ross 308 broiler chickens were randomly distributed to 24 floor pens (4 treatments, each consisting of 6 replicate pens; 15 chickens per pen) as a completely randomized design with 2 × 2 factorial arrangement of two levels of supplemental humate in feed (0 and 1 g/kg feed) and litter (0 and 5 g/kg litter). Growth performance, intestinal viscosity, litter quality, and incidence and severity of FPD in broilers were measured. In addition, malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined in blood and footpad tissues of broilers with different FPD scores. The results revealed that there was no interaction between humate supplementation to feed and litter. Neither dietary nor litter supplementation of humate had a significant effect on growth performance, intestinal viscosity, litter quality, and occurrence of FPD. And also, MDA and SOD levels in serum and footpad tissue did not affect by either dietary or litter supplementation of humate. The presence of FPD (score 1) had no effect on MDA and SOD levels in serum, however, increased the MDA and SOD levels (P < 0.001, P = 0.001, respectively) in footpad tissue of broilers. The intestinal viscosity did not differ between FPD scores 0 and 1. In conclusion, findings of this experiment suggest that humate supplementation to feed and litter did not alleviate FPD development in broilers fed diets based on barley. In addition, the presence of FPD lesions increases the MDA and SOD levels in the footpad tissues.

Emulsifier and Xylanase Can Modulate the Gut Microbiota Activity of Broiler Chickens

Simple Summary

Modern broiler nutrition, due to widely accepted goals of sustainable production, is concerned with the improvement of nutrient utilization. To achieve this, in our study, we used feed additives that improve the value of feed components. Due to the significant amounts of non-starch polysaccharides (which are not digested under broiler intestinal tract conditions and negatively affect broilers performance) in popular feed components like wheat, enzymes are needed. Furthermore, the use of emulsifiers to improve fat digestion is necessary, as young birds do not secrete sufficient enzyme and bile salts. Previous studies have shown that an additional increase in carbohydrate digestibility can be obtained by using an emulsifier containing xylanase in the feed. Presumably, the increase in carbohydrate digestibility occurred after adding the emulsifier. In our study, we aimed to investigate the effect of xylanase, emulsifier, and a combination of both in wheat diets with high level of tallow on the gastrointestinal tract microbiota activity of 480 one-day-old male ROSS 308 broiler chickens. The simultaneous usage of both additives in wheat-based diets with beef tallow reduces the ileum microbiota activity and enhances cecum microbiota activity. Presumably, the addition of both additives results in a cumulative effect on the gut microbiota activity.

Abstract

In this study, we aimed to investigate the effect of xylanase (XYL), emulsifier (EMU), and a combination of both (XYL + EMU) in wheat diet with a high level of tallow on gastrointestinal tract microbiota activity, excretion of sialic acids, and selected gut segments morphology of 480 one-day-old male ROSS 308 broiler chickens. The activities of bacterial enzymes in the ileal digesta were lower in experimental groups compared to the control (CON) group. Enzyme activity in the cecum was significantly higher than in the ileum. The additives did not affect the excretion of sialic acid. The number of duodenum goblet cells on the villi decreased in all of the experimental groups (p < 0.05). The simultaneous use of XYL + EMU deepened the ileum crypts (p < 0.05). The total short-chain fatty acid (SCFA) concentration in the cecal digesta was higher in experimental groups. The abundance of Bifidobacterium, Lactobacillus, and Escherichia coli did not change among experimental groups. The relative abundance of Clostridium was significantly (p < 0.05) lower in groups with emulsifier addition. In conclusion, the simultaneous usage of EMU and XYL in wheat-based diets with beef tallow reduces the ileum microbiota activity and enhances cecum microbiota activity. Presumably, the addition of both additives results in a cumulative effect on the gut microbiota activity.

Effect of Heat-Inactivated Compound Probiotics on Growth Performance, Plasma Biochemical Indices, and Cecal Microbiome in Yellow-Feathered Broilers

This study was carried out to investigate the effect of heat-inactivated compound probiotics on growth performance, plasma biochemical indices, and gut microbiota composition and functions in yellow-feathered broilers. A total of 360 1-day-old broilers were randomly divided into 3 groups, including a basal diet as negative control group (PC), basal diet plus antibiotics with 250 mg/kg calcium oxytetracycline and 200 mg/kg Nosiheptide as positive control (PC), and basal diet plus 500 mg/kg compound probiotics consisting of heat-inactivated Bacillus subtilis and Lactobacillus acidophilus BFI (BFI). Each group had 6 replicates of 20 chickens. On d 21, 42, and 63, one chick from each replicate was selected for blood collection and cecal sampling. Compared to the NC group, dietary supplementation with heat-inactivated compound probiotics increased the feed efficiency during d 1–63 (P < 0.05). The plasma cholesterol content at 42 d and creatinine content at 63 d were decreased by dietary supplementation with heat-inactivated compound probiotics (P < 0.05). The dominant phyla in broiler cecal microbiota were Bacteroidetes, Firmicutes, and Proteobacteria, while the dominant genera were Bacteroides, Ruminococcaceae, and Phascolarctobacterium. The β-diversity index of cecal microbiota in BFI group was increased at d 42 (P < 0.01) and d 63 (P < 0.05). Dietary heat-inactivated compound probiotics increased the relative abundances of Barnesiellaceae (family), Barnesiella (genus), and Lactobacillus aviarius (species) at d 21, and reduced the relative abundances of genera Lachnoclostridium and Peptococcus at d 42, and unidentified Lachnospiraceae and Lachnoclostridium at d 63. The functional prediction of microbiota revealed that supplementation with heat-inactivated compound probiotics enriched the pathways related to methane metabolism, transcription machinery, purine metabolism and protein export. The Spearman's correlation analysis identified a significant correlation between cecal microbiota composition and overall feed efficiency and plasma metabolites. Collectively, dietary heat-inactivated compound probiotics with Bacillus subtilis and Lactobacillus acidophilus BFI enhanced feed efficiency, and decreased plasma cholesterol and creatinine contents, which might be associated with the modulation of community composition, diversity and functions of cecal microbiota in yellow-feathered broilers. These results indicated the potential of heat-inactivated probiotics used as alternatives to antibiotics for improvement of broiler health and productivity.

Dietary Supplementation of Probiotic Lactobacillus acidophilus Modulates Cholesterol Levels, Immune Response, and Productive Performance of Laying Hens

Simple Summary

Chicken eggs provide a considerable source of high-quality nutrients for human food and health. However, egg consumption may harm some people for its high contents of cholesterol and association with cardiovascular disease risk. Therefore, we investigated the possible effect of using Lactobacillus acidophilus (LA) as a probiotic additive in the laying hens’ diets on lowering egg-yolk cholesterol and also evaluated the immune responses and the productive performance of laying hens. The obtained results display the ability of LA, when supplemented in hen diets, to decrease the plasma triglycerides and cholesterol levels and the liver and egg yolk cholesterols in the hen. The beneficial effects of LA were also explored on some important humoral and cell-mediated immune responses in the laying hens. These positive effects led to an improvement in the productive performance of laying hens. Therefore, dietary LA supplementation could be recommended as a nutritional strategy for commercial lower-cholesterol egg production in addition to positive impacts on the performance and health of laying hens.

Abstract

This study examines the effect of dietary supplementation with Lactobacillus acidophilus (LA) on the cholesterol levels, immune response, and productive performance of laying hens. A total of 216, 40-week-old, commercial Hy-Line brown chicken layers were randomly assigned into four treatment groups (18 birds × three replicates per group) and fed diet supplemented with 0 (control), 1 × 10⁹, 21 × 10⁹, and 31 × 10⁹ colony forming units (CFUs) of Lactobacillus acidophilus (LA) per kg of feed for six consecutive weeks. Results show that plasma triglycerides, low-density lipoprotein (LDL) and total cholesterols became lesser, while high-density lipoprotein (HDL) cholesterol became higher in LA-supplemented groups compared to the control. In addition, a significant reduction occurred in the liver and egg yolk cholesterol by LA supplementation. Moreover, the immunological parameters including antibody titer against sheep red blood cells (SRBCs), phytohemagglutinin (PHA)-wattle swelling test, and T- & B-lymphocyte proliferation were enhanced in laying hens supplemented with LA compared to the control hens. While the heterophil to lymphocyte (H/L) ratio decreased with LA supplementation, indicating low stress conditions in the treated hens. These positive effects for LA were further reflected on the productive performance of laying hens and improved egg production, egg weight, egg mass, and feed efficiency. Our findings indicate that LA probiotic could be recommended in laying hens’ diets for lowering egg yolk cholesterol with positive impacts on health and performance.

Probiotic Bacillus amyloliquefaciens H57 ameliorates subclinical necrotic enteritis in broiler chicks by maintaining intestinal mucosal integrity and improving feed efficiency

Subclinical necrotic enteritis (NE) was induced in broiler chicks using a high dose of Eimeria spp. vaccine in the drinking water on day 9, and Clostridium perfringens (Cp) culture mixed in the feed on days 14 and 15. The aim was to evaluate the effects of probiotic Bacillus amyloliquefaciens strain H57 (H57) in preventing NE in chicks. Day-old Ross 308, male broilers were weighed and randomly assigned to 6 treatment groups (6 replicate cages/treatment and 8 birds/cage). Birds in group 1 (control) were fed the basal wheat-soybean diet without H57 or NE infection; in group 2 (Eimeria) were treated with Eimeria alone; in group 3 (Cp) were treated with Cp alone; in group 4 (NE) received both Eimeria and Cp; in group 5 (NE-H57) received NE infection and H57; and group 6 (H57) received H57. The basal diet of chicks in groups 5 and 6 was supplemented with H57 at a density of 2 × 108 spores/g feed from 1 D of age. On day 21, there were no significant treatment effects on BW and feed intake between control and H57 birds. However, on day 21, the feed conversion ratio of NE-H57 birds was significantly improved when compared with NE birds (1.28 vs. 1.36; P < 0.001). Birds challenged with NE had a higher occurrence of pasty vent than birds infected with either Eimeria, Cp, or NE-H57 (41 vs. 27 vs. 29 vs. 19%, respectively; P < 0.001). Intestinal lesion scores of NE birds were also higher than those of Eimeria, Cp, and NE-H57 birds (5.67 vs. 2.56 vs. 2.78 vs. 2.10, respectively; P < 0.001) and correlated with pasty vent (Pearson's r = 0.56; P < 0.001). Microscopic evaluation showed mucosal damage and necrosis in NE birds. In contrast, villi from NE-H57 birds were normal, with no damage or infiltration with Eimeria or Cp. H57 appears to be effective in challenged birds, as it maintained epithelial barrier integrity and improved feed efficiency.

Effects of Gut Microbiome and Short-Chain Fatty Acids (SCFAs) on Finishing Weight of Meat Rabbits

Understanding how the gut microbiome and short-chain fatty acids (SCFAs) affect finishing weight is beneficial to improve meat production in the meat rabbit industry. In this study, we identified 15 OTUs and 23 microbial species associated with finishing weight using 16S rRNA gene and metagenomic sequencing analysis, respectively. Among these, butyrate-producing bacteria of the family Ruminococcaceae were positively associated with finishing weight, whereas the microbial taxa related to intestinal damage and inflammation showed opposite effects. Furthermore, interactions of these microbial taxa were firstly found to be associated with finishing weight. Gut microbial functional capacity analysis revealed that CAZymes, such as galactosidase, xylanase, and glucosidase, could significantly affect finishing weight, given their roles in regulating nutrient digestibility. GOs related to the metabolism of several carbohydrates and amino acids also showed important effects on finishing weight. Additionally, both KOs and KEGG pathways related to the membrane transportation system and involved in aminoacyl-tRNA biosynthesis and butanoate metabolism could act as key factors in modulating finishing weight. Importantly, gut microbiome explained nearly 11% of the variation in finishing weight, and our findings revealed that a subset of metagenomic species could act as predictors of finishing weight. SCFAs levels, especially butyrate level, had critical impacts on finishing weight, and several finishing weight-associated species were potentially contributed to the shift in butyrate level. Thus, our results should give deep insights into how gut microbiome and SCFAs influence finishing weight of meat rabbits and provide essential knowledge for improving finishing weight by manipulating gut microbiome.

Lactobacillus ingluviei C37 from chicken inhibits inflammation in LPS-stimulated mouse macrophages

Probiotics are growing alternatives to antibiotics, and can contribute to the prevention and treatment of diseases and enhance livestock production. Lactobacillus (L.) ingluviei is a novel probiotic species with growth-enhancement effects; however, this species remains poorly understood, and there have been (to our knowledge) no studies focusing on its immunological effects. Here, we isolated L. ingluviei C37 (LIC37) from chicken and evaluated the bacterium's immunomodulatory properties to explore its probiotic potential. Real-time quantitative PCR and ELISA showed that in vitro exposure of inflammation-stimulated mouse peritoneal macrophages to heat-killed LIC37 led to decreases in tumor necrosis factor-α and interleukin (IL)-6 levels and an increase in IL-10. These findings suggested that LIC37 exerts anti-inflammatory effects by modulating cytokine profiles. This species may be an attractive probiotic bacterial strain for use in animal production.