Community composition of cecal microbiota in commercial yellow broilers with high and low feed efficiencies

Metagenomics-Metabolomics Exploration of Three-Way-Crossbreeding Effects on Rumen to Provide Basis for Crossbreeding Improvement of Sheep Microbiome and Metabolome of Sheep

The objective of this experiment was to explore the effects of three-way hybridization on rumen microbes and metabolites in sheep using rumen metagenomics and metabolomics. Healthy Hu and CAH (Charolais × Australian White × Hu) male lambs of similar birth weight and age were selected for short-term fattening after intensive weaning to collect rumen fluid for sequencing. Rumen metagenomics diversity showed that Hu and CAH sheep were significantly segregated at the species, KEGG-enzyme, and CAZy-family levels. Moreover, the CAH significantly increased the ACE and Chao1 indices. Further, correlation analysis of the abundance of the top 80 revealed that the microorganisms were interrelated at the species, KEGG-enzyme, and CAZy-family levels. Overall, the microbiome significantly affected metabolites of the top five pathways, with the strongest correlation found with succinic acid. Meanwhile, species-level microbial markers significantly affected rumen differential metabolites. In addition, rumen microbial markers in Hu sheep were overall positively correlated with down-regulated metabolites and negatively correlated with up-regulated metabolites. In contrast, rumen microbial markers in CAH lambs were overall negatively correlated with down-regulated metabolites and positively correlated with up-regulated metabolites. These results suggest that three-way crossbreeding significantly affects rumen microbial community and metabolite composition, and that significant interactions exist between rumen microbes and metabolites.

Measuring the impact of dietary supplementation with citrus or cucumber extract on chicken gut microbiota using 16s rRNA gene sequencing

This study investigated the effects of dietary supplements, citrus (CTS) and cucumber (CMB), on the jejunum and cecum microbiota of 14- and 28-days old broiler chickens to evaluate their impact on the gut health and assess their role as alternatives to antibiotic growth promoters (ABGPs). 16SrRNA gene sequencing revealed the overall bacterial microbiota composition was significantly affected by the gut site (p? Collapse

Key Words

• 16SrRNA gene sequencing
• Broiler chicken
• Citrus
• Cucumber
• Gut microbiota
• Novel plant extracts

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MESH Headings

• Animals
• Gastrointestinal Microbiome/drug effects
• Dietary Supplements/analysis
• Chickens/microbiology
• RNA, Ribosomal, 16S/genetics
• Citrus/chemistry
• Animal Feed/analysis
• Diet/veterinary
• Plant Extracts/pharmacology
• Plant Extracts/administration & dosage
• Cucumis sativus/microbiology
• Cecum/microbiology
• Jejunum/microbiology

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Grants

• 765423 Horizon 2020

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Affiliation(s)

Francesca Riva School of Health and Life Sciences, University of the West of Scotland, High St, PA1 2BE, Paisley, UK School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Bearsden Rd, G61 1QH, Glasgow, UK Faculty of Veterinary Medicine, University of Zagreb, Radoslava Cimermana, 10000, Zagreb, Croatia
David H McGuinness Glasgow Polyomics, University of Glasgow, Switchback Rd, G61 1BD, Bearsden, Glasgow, UK
Dorothy E F McKeegan School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Bearsden Rd, G61 1QH, Glasgow, UK
Jorge Peinado-Izaguerri School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Bearsden Rd, G61 1QH, Glasgow, UK Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Ko?ice, Komensk?ho, 041 81, Ko?ice, Slovakia School of Biological Sciences, The University of Manchester, Oxford Rd, M13 9PT, Manchester, UK
Geert Bruggeman Nutrition Sciences N. V, B-9031, Booiebos, Ghent, Belgium
David Hermans Nutrition Sciences N. V, B-9031, Booiebos, Ghent, Belgium
Peter D Eckersall School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Bearsden Rd, G61 1QH, Glasgow, UK
Mark McLaughlin School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Bearsden Rd, G61 1QH, Glasgow, UK.
Maureen Bain School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Bearsden Rd, G61 1QH, Glasgow, UK

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The baicalein amorphous solid dispersion to enhance the dissolution and bioavailability and effects on growth performance, meat quality, antioxidant capacity and intestinal flora in Taihang chickens

Baicalein (BAI) is a natural flavonoid with antioxidant, antitumor and antibacterial properties. However, the bioavailability of BAI was limited due to low solubility. This study aims to improve the solubility of BAI through the amorphous solid dispersion (ASD) and evaluate changes in its pharmacokinetics and pharmacodynamics in Taihang chickens. Polyethylene caprolactam-polyvinyl acetate-polyethylene glycol grafted copolymer (Soluplus) was chosen as the carrier, and ASD was prepared by rotary evaporation and was characterized by powder X-ray diffractions (PXRD), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR). In vitro dissolution assays were used to screen the optimal ratio of drug to carrier, in vivo pharmacokinetic assays were conducted to investigate the promoting effect on the absorption. In addition, the effects of ASD on the growth performance, meat quality, antioxidant capacity and intestinal flora were investigated. ASD (1:9 and 2:8) did not exhibit crystal diffraction peaks of BAI in PXRD or endothermic peaks in DSC, indicating the successful preparation of ASD. The results of in vitro dissolution assay showed that the cumulative dissolution rate of ASD (2:8) within 600 min was 52.67%, which was 7.84-fold higher than BAI. The pharmacokinetic results showed that the peak concentration (Cmax) and the area under the drug-time curve (AUC0∼24) of ASD (2:8) was (5.20 ± 0.82) μg/mL and (17.03 ± 0.67) μg·h/mL, which was 1.91 and 2.64-fold higher than BAI, respectively. Dietary supplementation of BAI and ASD could increase average daily gain (ADG), while decrease feed conversion ratio (FCR), but there was no significant difference (P > 0.05). The drip loss of BAIASD group was lower than BAI group (P < 0.05). In addition, the antioxidant capacity of Taihang chickens were enhanced, the diversity and the abundance of beneficial bacteria was improved. Results of BAI upon the dietary supplementation tested in Taihang chickens, after preparation of ASD, indicating a superior enhancement effect in growth performance, meat quality, antioxidant capacity and intestinal flora due to an improved solubility and optimized bioavailability.

Are there consistent effects of gut microbiota composition on performance, productivity and condition in poultry?

Microbiome of the gastrointestinal tract (GIT) has been identified as one of the crucial factors influencing the health and condition of domestic animals. The global poultry industry faces the challenge of understanding the complex relationship between gut microbiota composition and performance-related traits in birds. Considerable variation exists in the results of correlational studies using either 16S rRNA profiling or metagenomics to identify bacterial taxa associated with performance, productivity, or condition in poultry (e.g., body weight, growth rate, feeding efficiency, or egg yield). In this review, we survey the existing reports, discuss variation in research approaches, and identify bacterial taxa consistently linked to improved or deteriorated performance across individual poultry-focused studies. Our survey revealed high methodological heterogeneity, which was in contrast with vastly uniform focus of the research mainly on the domestic chicken (Gallus gallus) as a model. We also show that the bacterial taxa most frequently used in manipulative experiments and commercial probiotics intended for use in poultry (e.g., species of Lactobacillus, Bacillus, Enterococcus, or Bifidobacterium) do not overlap with the bacteria consistently correlated with their improved performance (Candidatus Arthromitus, Methanobrevibacter). Our conclusions urge for increased methodological standardization of the veterinary research in this field. We highlight the need to bridge the gap between correlational results and experimental applications in animal science. To better understand causality in the observed relationships, future research should involve a broader range of host species that includes both agricultural and wild models, as well as a broader range of age groups.

Relationship between Rumen Microbial Differences and Phenotype Traits among Hu Sheep and Crossbred Offspring Sheep

This experiment was conducted to investigate the effect of three-way hybrid sheep and Hu sheep on serum indicators, rumen fermentation, rumen enzyme activity, and microorganisms in sheep. Healthy and similar birth weights from three groups (Hu, n = 11; Charolais × Australian White × Hu, CAH, n = 11; Charolais × Dorper × Hu, CDH, n = 11) were selected to be fed by the ewes until 45 days of age. Subsequently, they were weaned intensively and underwent short-term fattening for 3 months along with selected male lambs fed intensively. During this period, they were fed and watered ad libitum. Blood and rumen fluid were collected and analyzed for serum indicators and rumen fluid microorganisms, enzyme activity, and VFA, respectively, at the end of the fattening period. Compared with Hu lamb, the offspring of the three-way hybrid lamb showed significant improvements in body weight, serum lactate dehydrogenase, and creatinine content. However, there was no significant effect on serum immunity and antioxidant indices. In addition, the rumen fluid volatile fatty acid (VFA) molar concentration and microcrystalline cellulose and lipase content were significantly lower in the three-way hybrid lamb compared to Hu lamb, but β-glucosidase, amylase, pepsin, and VFA molar ratio were not significantly affected. Subsequently, 16S rRNA sequencing diversity analysis revealed that three-way hybrid lamb significantly increased rumen microbial ACE and Chao1 indices compared to Hu lamb. Meanwhile, the abundance of Verrucomicrobiota and Synergistota significantly increased at the phylum level. Correlation analysis showed that Prevotella had the highest proportion, while Rikenellaceae_RC9_gut_group correlated most closely with others genus. The microbial communities isovaleric acid molar concentration and proportion were strongly correlated. In addition, there were significant differences in correlations between microbial communities and isobutyric acid, butyric acid and valeric acid content, and their molar proportion, but they were not significantly correlated with digestive enzymes. From the functional enrichment analysis, it was found that hybrid progeny were mainly enriched in the pyruvate metabolism, microbial metabolism in diverse environments, carbon metabolism, and quorum sensing pathways. In contrast, the Hu sheep were primarily enriched in the cysteine and methionine, amino sugar and nucleotide sugar, and biosynthesis of secondary metabolite pathways. These results suggest that hybridization can play a role in regulating organismal metabolism and improve animal production performance by influencing the structure and characteristics of microbial communities.

Genome-wide detections for runs of homozygosity and selective signatures reveal novel candidate genes under domestication in chickens

BACKGROUND

Indigenous chickens were developed through a combination of natural and artificial selection; essentially, changes in genomes led to the formation of these modern breeds via admixture events. However, their confusing genetic backgrounds include a genomic footprint regulating complex traits, which is not conducive to modern animal breeding.

RESULTS

To better evaluate the candidate regions under domestication in indigenous chickens, we considered both runs of homozygosity (ROHs) and selective signatures in 13 indigenous chickens. The genomes of Silkie feather chickens presented the highest heterozygosity, whereas the highest inbreeding status and ROH number were found in Luhua chickens. Short ROH (< 1 Mb), were the principal type in all chickens. A total of 291 ROH islands were detected, and QTLdb mapping results indicated that body weight and carcass traits were the most important traits. An ROH on chromosome 2 covering VSTM2A gene was detected in 12 populations. Combined analysis with the Tajima's D index revealed that 18 genes (e.g., VSTM2A, BBOX1, and RYR2) were under selection and covered by ROH islands. Transcriptional analysis results showed that RYR2 and BBOX1 were specifically expressed in the heart and muscle tissue, respectively.

CONCLUSION

Based on genome-wide scanning for ROH and selective signatures, we evaluated the genomic characteristics and detected significant candidate genes covered by ROH islands and selective signatures. The findings in this study facilitated the understanding of genetic diversity and provided valuable insights for chicken breeding and conservation strategies.

Exploration of risk analysis and elimination methods for a Cr(VI)-removal recombinant strain through a biosafety assessment in mice

Though recombinant strains are increasingly recognized for their potential in heavy metal remediation, few studies have evaluated their safety. Moreover, biosafety assessments of fecal-oral pathway exposure at country as well as global level have seldom analyzed the health risks of exposure to microorganisms from a microscopic perspective. The present study aimed to predict the long-term toxic effects of recombinant strains by conducting a subacute toxicity test on the chromium-removal recombinant strain 3458 and analyzing the gut microbiome. The available disinfection methods were also evaluated. The results showed that strain 3458 induced liver damage and affected renal function and lipid metabolism at 1.0 × 1011 CFU/mL, which may be induced by its carrier strain, pET-28a. Strain 3458 poses the risk of increasing the number of pathogenic bacteria under prolonged exposure. When 500 mg L-1 chlorine-containing disinfectant or 250 mg L-1 chlorine dioxide disinfectant was added for 30 min, the sterilization rate exceeded 99.9 %. These findings suggest that existing wastewater disinfection methods can effectively sterilize strain 3458, ensuring its application value. The present study can serve a reference for the biosafety evaluation of the recombinant strain through exposure to the digestive tract and its feasibility for application in environmental pollution remediation.

Metagenome-assembled genome reveals species and functional composition of Jianghan chicken gut microbiota and isolation of Pediococcus acidilactic with probiotic properties

BACKGROUND

Chickens are one of the most widely farmed animals worldwide and play a crucial role in meat and egg production. Gut microbiota is essential for chickens' health, disease, growth, and egg production. However, native chickens such as Jianghan chickens have better meat and egg production quality than centralized chickens, their intestinal microbial diversity is richer, and the potential gut microbial resources may bring health benefits to the host.

RESULTS

The bacterial species composition in the gut microbiota of Jianghan chickens is similar to that of other chicken breeds, with Phocaeicola and Bacteroides being the most abundant bacterial genera. The LEfSe analysis revealed significant differences in species composition and functional profiles between samples from Jingzhou and the other three groups. Functional annotation indicated that the gut microbiota of Jianghan chickens were dominated by metabolic genes, with the highest number of genes related to carbohydrate metabolism. Several antibiotic resistance genes (ARGs) were found, and the composition of ARGs was similar to that of factory-farmed chickens, suggesting that antibiotics were widely present in the gut microbiota of Jianghan chickens. The resistance genes of Jianghan chickens are mainly carried by microorganisms of the Bacteroidota and Bacillota phylum. In addition, more than 829 isolates were selected from the microbiota of Jianghan chickens. Following three rounds of acid and bile tolerance experiments performed on all the isolated strains, it was determined that six strains of Pediococcus acidilactici exhibited consistent tolerance. Further experiments confirmed that three of these strains (A4, B9, and C2) held substantial probiotic potential, with P. acidilactici B9 displaying the highest probiotic potential.

CONCLUSIONS

This study elucidates the composition of the intestinal microbiota and functional gene repertoire in Jianghan chickens. Despite the absence of antibiotic supplementation, the intestinal microbial community of Jianghan chickens still demonstrates a profile of antibiotic resistance genes similar to that of intensively reared chickens, suggesting resistance genes are prevalent in free-ranging poultry. Moreover, Jianghan and intensively reared chickens host major resistance genes differently, an aspect seldom explored between free-range and pastured chickens. Furthermore, among the 829 isolates, three strains of P. acidilatici exhibited strong probiotic potential. These findings provide insights into the unique gut microbiota of Jianghan chickens and highlight potential probiotic strains offering benefits to the host. Video Abstract.

Enzymolytic soybean meal improves growth performance, economic efficiency and organ development associated with cecal fermentation and microbiota in broilers offered low crude protein diets

The objective of this experiment was to determine the effect of low crude protein (CP) diets containing increasing amounts of enzymolytic soybean meal (ESBM) on growth performance, economic benefit and organ development and the role of cecal fermentation and microbiota in broilers. A total of 360 one-day-old Arbor Acres chicks were randomly allocated into 6 groups with 6 replicates and 10 chicks each. The six dietary treatments consisted of a standard high-CP diet (PC), a low-CP diet (NC), and an NC diet with 0.5, 1.0, 1.5%, or 2.0% ESBM. The experiment lasted for 42 days. Compared to PC, NC showed decreased (p < 0.05) average daily gain (ADG) in broilers from 22 to 42 days and from 1 to 42 days, while increasing levels of ESBM quadratically increased (p < 0.05) ADG from 1 to 42 days. Feed cost and total revenue in the NC were lower (p < 0.05) than that in the PC, while supplementation with ESBM in the NC linearly increased (p < 0.05) net profit and economic efficiency in broilers. There were significant differences (p < 0.05) in the liver, proventriculus and gizzard indices between the PC and NC groups, and supplementation with ESBM linearly increased (p < 0.05) the relative weights of liver, pancreas, proventriculus and gizzard in broilers at 42 days of age. The PC group had a higher cecal acetic acid concentration at 21 days and propionic acid concentration at both 21 and 42 days than the NC group (p < 0.05). Cecal acetic acid and propionic acid concentrations linearly increased (p < 0.05) with increasing levels of ESBM in broilers at 42 days of age. No significant differences in ACE, Chao1, Shannon and Simpson indices were observed among groups (p > 0.05), while the cecal abundances of Bacteroides, Faecalibacterium and Clostridium IV increased (p < 0.05) with the increasing level of ESBM in the low-CP diets. In conclusion, feeding ESBM improved economic efficiency, digestive organ development, cecal fermentation and microbial community composition, and up to 2.0% ESBM addition had no negative effect on the growth performance in broilers fed low CP diets.

The digestive tract histology and geographical distribution of gastrointestinal microbiota in yellow-feather broilers

Exhaustive understanding of intestinal physiological characteristics is the critical precondition for the improvement of intestinal health and growth performance of yellow-feather broilers (YFB). As a vital part of gastrointestinal tract, the symbiotic, complex, and variable microbiota have a profound effect on the nutrition, immunity, health, and production of broilers. Hence, the development status of proventriculus, jejunum, and cecum, and spatial heterogeneity of bacterial community in crop, proventriculus, gizzard, jejunum, cecum, and rectum of adult YFB were detected in our study. The results revealed that proventriculus, jejunum, and cecum of broilers are well-developed based on morphological observation. The Chao and Shannon indexes in cecum and rectum are notably higher than other sections and their microbiota structure is also distinct from foregut. Firmicutes and Lactobacillus are the predominant phylum and genus in all gastrointestinal sections, respectively. As feature species of crop, Lactobacillus spp. mainly settle in foregut, whereas some Clostridia species (unclassified Lachnospiraceae, Faecalibacterium, Romboutsia and so on) are characteristic and more abundant in cecum and rectum. Interestingly, there are 2 Ruminococcus torques strains positively and negatively correlated with cecum development, respectively. In a whole, our findings reveal the specialized digestive physiology and regional distribution of intestinal microbiota in YFB, which provides a reference for the future study on the improvement of growth performance and intestinal development through microbiota manipulation in yellow-feather broilers.

Effect of replacement of soybean oil by Hermetia illucens fat on performance, digestibility, cecal microbiome, liver transcriptome and liver and plasma lipidomes of broilers

BACKGROUND

In contrast to protein-rich insect meal, the feed potential of insect fat is generally less explored and knowledge about the suitability of insect fat as a fat source specifically in broiler diets is still limited. In view of this, the present study aimed to comprehensively investigate the effect of partial (50%) and complete replacement of soybean oil with insect fat from Hermetia illucens (HI) larvae in broiler diets on performance, fat digestibility, cecal microbiome, liver transcriptome and liver and plasma lipidomes. Thus, 100 male, 1-day-old Cobb 500 broilers were randomly assigned to three groups and fed three different diets with either 0 (group HI-0, n = 30), 2.5% (group HI-2.5, n = 35) or 5.0% (HI-5.0, n = 35) Hermetia illucens (HI) larvae fat for 35 d.

RESULTS

Body weight gain, final body weight, feed intake, and feed:gain ratio during the whole period and apparent ileal digestibility coefficient for ether extract were not different between groups. Cecal microbial diversity did not differ between groups and taxonomic analysis revealed differences in the abundance of only four low-abundance bacterial taxa among groups; the abundances of phylum Actinobacteriota, class Coriobacteriia, order Coriobacteriales and family Eggerthellaceae were lower in group HI-5.0 compared to group HI-2.5 (P < 0.05). Concentrations of total and individual short-chain fatty acids in the cecal digesta were not different between the three groups. Liver transcriptomics revealed a total of 55 and 25 transcripts to be differentially expressed between groups HI-5.0 vs. HI-0 and groups HI-2.5 vs. HI-0, respectively (P < 0.05). The concentrations of most lipid classes, with the exception of phosphatidylethanolamine, phosphatidylglycerol and lysophosphatidylcholine in the liver and cholesterylester and ceramide in plasma (P < 0.05), and of the sum of all lipid classes were not different between groups.

CONCLUSIONS

Partial and complete replacement of soybean oil with HI larvae fat in broiler diets had no effect on growth performance and only modest, but no adverse effects on the cecal microbiome and the metabolic health of broilers. This suggests that HI larvae fat can be used as an alternative fat source in broiler diets, thereby, making broiler production more sustainable.

Effects of citrus pulp on the composition and diversity of broiler cecal microbes

Diet may affect gut microbial composition and diversity. There were 3 dietary groups: 0% citrus pulp diet (C), 1.5% citrus pulp diet (I), and 2.5% citrus pulp diet (II). A total of 180 healthy AA broilers (21-day old) were divided into 3 groups (C, I, and II), each group was set up with 6 replicates, and each replicate including 10 broilers (half male and female). At 42 d, the cecal contents of 18 broiler chickens were collected after slaughter. The cecal contents were analyzed using 16S rRNA sequencing technology. Compared with group C, the abundance of Firmicutes in groups I and II decreased, while the relative abundances of Bacteroidetes, Verrucomicrobia, Lactobacillus, and Faecalibacterium increased. LEfSe analysis showed that Actinobacteria, Coriobacteriia, Coriobacteriales, and Ruminococcaceae_bacterium_Marseille_P2935 in group I were significantly higher than those in group C. Bacteria, Coriobacteriales, Coriobacteriia, Coriobacteriaceae, Slackia, Bacteroides_sp_Marseille_P3132, and Lactobacillus_pontis in group II were significantly higher than those in group C. The Staphylococcaceae, Bacteroides_sp_Marseille_P3132, Macroccus, Lactobacillus_pontis, and Streptococcus_equinus in group II were significantly higher than those in group I. Functional predictions indicated that the cecal microbiota of broilers fed the 2.5% citrus pulp diet was more tend to utilize carbohydrates through glycolytic/gluconeogenesis metabolism. Adding citrus pulp to the diet affects the microbial composition and has important implications for studying gut health and improving economic benefits.

Compound mycotoxin detoxifier alleviating aflatoxin B1 toxic effects on broiler growth performance, organ damage and gut microbiota

The aim of this study was to evaluate the effects of compound mycotoxin detoxifier (CMD) on alleviating the toxic effect of aflatoxin B₁ (AFB₁) for broiler growth performance. One-kilogram CMD consists of 667 g aflatoxin B₁-degrading enzyme (ADE, 1,467 U/g), 200 g montmorillonite and 133 g compound probiotics (CP). The feeding experiment was divided into 2 stages (1-21 d and 22-42 d). In the early stage, a total of 300 one-day-old Ross broilers were randomly divided into 6 groups, 5 replications for each group, 10 broilers (half male and half female) in each replication. In the later feeding stage, about 240 twenty-two-day-old Ross broilers were randomly divided into 6 groups, 8 replications for each group, 5 broilers in each replication. Group A: basal diet; group B: basal diet with 40 μg/kg AFB₁; group C: basal diet with 1 g/kg CMD; groups D, E, and F: basal diet with 40 μg/kg AFB₁ plus 0.5, 1.0 and 1.5 g/kg CMD, respectively. The results indicated that AFB₁ significantly decreased average daily gain (ADG), protein metabolic rate, organ index of thymus, bursa of Fabricius (BF), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and catalase activities in serum, and increased AFB₁ residues in serum and liver (P < 0.05). Hematoxylin-Eosin (HE) staining analysis of jejunum, liver and kidney showed that AFB₁ caused the main pathological changes with different degrees of inflammatory cell infiltration. However, CMD additions could alleviate the negative effects of AFB₁ on the above parameters. The gut microbiota analysis indicated that AFB₁ could significantly increase the abundances of Staphylococcus-xylosu, Esherichia-coli-g-Escherichia-Shigella, and decrease Lactobacillus-aviarius abundance (P < 0.05), but which were adjusted to almost the same levels as the control group by CMD addition. The correlative analysis showed that Lactobacillus-aviarius abundance was positively correlated with ADG, SOD and BF (P < 0.05), whereas Staphylococcus-xylosus abundance was positively correlated with AFB₁ residues in serum and liver (P < 0.05). In conclusion, CMD could keep gut microbiota stable, alleviate histological lesions, increase growth performance, and reduce mycotoxin toxicity. The optimal CMD addition should be 1 g/kg in AFB₁-contaminated broilers diet.

Bifidobacterium animalis Promotes the Growth of Weaning Piglets by Improving Intestinal Development, Enhancing Antioxidant Capacity, and Modulating Gut Microbiota

In the modern swine industry, weaning is a critical period in the pig’s life cycle. Sudden dietary, social, and environmental changes can easily lead to gut microbiota dysbiosis, diarrhea, and a decrease in growth performance.

Metagenomic analysis reveals the microbiome and antibiotic resistance genes in indigenous Chinese yellow-feathered chickens

Yellow-feathered chickens have great nutritional value and are widely and traditionally used in China, on an industrial scale as broilers. The presence of intestinal microbes has been shown to correlate with poultry performance and serves as an essential reservoir of antibiotic resistance genes (ARGs). Antibiotic resistance is a major public health concern. Here, we investigated functional characteristics of the gut microbiome of indigenous Chinese yellow-feathered chickens (the Huiyang Bearded, Xinghua, Huaixiang, Zhongshan Shanlan, Qingyuan Partridge, and Yangshan chickens) through metagenomic sequencing and reconstructed 409 draft genomes, including 60 novel species and 6 novel genera. Furthermore, we assessed the functions of the intestinal microbial communities and examined the ARGs within them. The results showed that the microbial populations of yellow-feathered broilers were primarily dominated by Bacteroidetes and Firmicutes at the phylum level and Bacteroides at the genus level. Furthermore, the Qingyuan Partridge chicken showed a significantly higher abundance of Prevotella than the other five breeds of chicken. Principal coordinates analysis indicated significant differences in the structures of microbial communities and ARGs, based on the binary Jaccard distance, among the six chicken breeds. Moreover, 989 ARGs conferring tetracycline, multidrug, and aminoglycoside resistance were identified, which represented more than 80% of the faecal resistomes; the most abundant gene in the yellow-feathered chickens was tet(Q). In addition, we found the greatest abundance of resistance genes in Xinghua chickens, indicating that Xinghua chickens are highly resistant to antibiotics. Overall, our findings revealed differences in the gut microbial community structure of indigenous Chinese yellow-feathered broiler breeds and the composition and characteristics of ARGs and antibiotic resistance that enabled us to reconstruct the yellow-feathered chicken gut microbial community genomes. The current data significantly improves our knowledge of the gut microbiome and antibiotic resistance of popular broiler breeds in China.

Effects of Dietary Macleaya cordata Extract on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers Subjected to Chronic Heat Stress

This study investigated the effect of dietary Macleaya cordata extract (MCE) supplementation on the growth performance, serum parameters, and intestinal microbiota of yellow-feather broilers under heat stress. A total of 216 yellow-feather broilers (28-days-old) were randomly allotted into three groups. A control group (CON) (24 ± 2 °C) and heat stress group (HS) (35 ± 2 °C) received a basal diet, and heat-stressed plus MCE groups (HS-MCE) (35 ± 2 °C) were fed the basal diet with 1000 mg/kg MCE for 14 consecutive days. The results revealed that MCE supplementation improved the final body weight, average daily feed intake, average daily gain, and spleen index when compared with the HS group (p < 0.05). In addition, MCE supplementation decreased (p < 0.05) the activities of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatinine, and increased (p < 0.05) the glucose level and alkaline phosphatase activity in heat-stressed yellow-feathered broilers. Moreover, MCE treatment alleviated heat-stress-induced intestinal flora disturbances, decreased the Bacteroidota and Bacteroides relative abundances, and increased Firmicutes. A linear discriminant analysis effect size analysis found five differentially abundant taxa in the HS-MCE group, including Alistipes, Rikenellaceae, Mogibacterium, Butyrivibrio, and Lachnospira. These results suggest that MCE can alleviate HS-induced decline in growth performance by modulating blood biochemical markers and cecal flora composition in broilers.

Effects of dietary palygorskite supplementation on the growth performance, oxidative status, immune function, intestinal barrier and cecal microbial community of broilers

The present study aimed to investigate the effects of palygorskite (PAL) as an alternative to antibiotic on the growth performance, oxidative status, immune function, intestinal barrier and cecal microbial community of broilers. A total of 360 1-day-old male Ross-308 broilers were randomly allotted to three treatments with eight replicates. Broilers in the three groups were designated as follows: basal diet (CON group), basal diet+50 mg/kg chlorotetracycline (ANT group), and basal diet+ 10 g/kg PAL (PAL group). Supplementing PAL reduced feed to gain ratio in broilers during 22 to 42 days of age (P &lt; 0.05), with its value being similar to that of the ANT group (P &gt; 0.05). Broilers fed a PAL-supplemented diet exerted decreased contents of interferon-γ (IFN-γ) and interleukin-1β in serum, and the same reduction was found in jejunal IFN-γ level, when compared to the CON group (P &lt; 0.05). Moreover, compared with the CON group, broilers after PAL treatment had a lower malondialdehyde content in jejunal mucosa (P &lt; 0.05). Supplementing PAL elevated jejunal villus height (VH) and ratio of VH to crypt depth compared with the ANT group (P &lt; 0.05). Cecal microbiota communities among the three groups were significant different, as demonstrated by distinct clusters from partial least squares discriminant analysis, although dietary treatments had no significant effects on the bacterial richness and diversity indices (P &gt; 0.05). At genus level, the addition of PAL increased the relative abundance of norank_f__Barnesiellaceae and decreased that of unclassified_f__Oscillospiraceae in cecal digesta compared with those in the CON group (P &lt; 0.05); the proportion of genus norank_f__Barnesiellaceae was increased by PAL treatment when compared with the ANT group (P &lt; 0.05). Moreover, spearman's correlations showed that the modulation of cecal microflora composition by PAL supplementation was closely correlated with the promotion of growth performance (feed to gain ratio) and intestinal health-related (contents of malondialdehyde and IFN-γ, and VH value in jejunum) variables of broilers (P &lt; 0.05). Taken together, dietary PAL could improve the growth performance, antioxidant capacity, and immune status, as well as intestinal barrier function in broilers, which might be partially associated with the alteration of cecal microbiota. Moreover, dietary PAL may be a promising alternative to antibiotic growth promoter for broilers.

High Temperature-Induced Oxidative Stress Affects Systemic Zinc Homeostasis in Broilers by Regulating Zinc Transporters and Metallothionein in the Liver and Jejunum

To investigate the change in zinc homeostasis of broilers under heat stress, 512 broiler chickens were raised to the age of 28 days. The broilers were then assigned to heat stress and normal temperature (36.0°C vs. 26.0°C) groups for 7 days. The results showed that oxidative stress induced by high temperature had a negative effect on the growth performance of broilers. Heat stress altered zinc homeostasis and led to a redistribution of zinc in broilers, which was reflected in increased zinc concentrations in the jejunum, liver, and tibia. Upregulation of the expression of the zinc exporter ZnT1 and importers ZIP8 and ZIP14 in the jejunum indicated that more zinc was absorbed and transported from the jejunum into the blood, while the liver increased its capacity to hold zinc through upregulation of metallothionein (MT) expression, which was achieved by reducing ZnT1 expression and upregulating the expression of the importer ZIP3. The pathway was mediated by zinc transporters, but the capacity of MT to chelate and release zinc ions also played a crucial role. The mechanism of alterations in zinc homeostasis under heat stress was revealed by the changes in zinc transporters and MT levels in the intestine and liver. Heat stress also altered cecal microbial diversity and reduced the relative abundances of Bilophila and Dialister. In conclusion, broilers altered systemic zinc homeostasis through the regulation of zinc transporters and MT in the liver and jejunum to resist oxidative stress induced by high temperature.

Oscillospira - a candidate for the next-generation probiotics

Oscillospira is a class of organism that often appears in high-throughput sequencing data but has not been purely cultured and is widely present in the animal and human intestines. There is a strong association between variation in Oscillospira abundance and obesity, leanness, and human health. In addition, a growing body of studies has shown that Oscillospira is also implicated in other diseases, such as gallstones and chronic constipation, and has shown some correlation with the positive or negative changes in its course. Sequencing data combined with metabolic profiling indicate that Oscillospira is likely to be a genus capable of producing short-chain fatty acids (SCFAs) such as butyrate, which is an important reference indicator for screening "next-generation probiotics ". Considering the positive effects of Oscillospira in some specific diseases, such as obesity-related metabolic diseases, it has already been characterized as one of the next-generation probiotic candidates and therefore has great potential for development and application in the future food, health care, and biopharmaceutical products.

Effects of Dietary Tributyrin on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers

This study aimed to evaluate the effects of tributyrin on growth performance, biochemical indices and intestinal microbiota of yellow-feathered broilers. 360 one-day-old chicks were randomly allocated to three treatments with six replicates of 20 chicks each, including a normal control group (NC), an antibiotic group (PC), and a tributyrin (250 mg/kg) group (TB) for 63 days. The results showed that compared with the control, the feed conversion ratio (FCR) in the TB group decreased during the d22 to d42 (p < 0.05) and overall, the final weight and FCR of broilers tended to increase and decrease, respectively. Moreover, the TB group showed the highest creatine concentrations at the entire period (p < 0.05). TB treatment increased the Bacteroidetes relative abundance and decreased Firmicutes. Principal coordinates analysis yielded clear clustering of the three groups. Linear discriminant analysis effect size analysis found seven differentially abundant taxa in the TB group, including several members of Bacteroidedetes. The relative abundance of Eisenbergiella, Phascolarctobacterium, Megasphaera and Intestinimonas increased in tributyrin-treated broilers. Spearman correlation analysis identified a correlation between Eisenbergiella abundance and overall feed efficiency. These results demonstrated that tributyrin could improve the growth performance by modulating blood biochemical indices and the cecal microflora composition of broilers.

Microbial Composition in the Duodenum and Ileum of Yellow Broilers With High and Low Feed Efficiency

The composition of the gut microbiome plays important roles in digestion, nutrient absorption, and health. Here, we analyzed the microbial composition in the duodenum and ileum of yellow broilers. Chickens were grouped based on feed efficiency (high feed efficiency [HFE] and low feed efficiency [LFE] groups; n = 22 each). Microbial samples from the duodenum and ileum were collected, and 16S rRNA sequencing of the V3–V4 region was performed. The dominant bacteria in the duodenum were from the phyla Firmicutes and Cyanobacteria and the genera Lactobacillus, Faecalibacterium, and Ruminococcus. In the ileum, the phyla Firmicutes and Proteobacteria and the genera Lactobacillus, SMB53 and Enterococcus were predominant. Alpha diversity analysis showed that the microbiota diversity was significantly higher in the duodenum than in the ileum. The structure of the ileal microbiota was similar between groups, and the species richness of the microbiota in the HFE group was significantly higher than that in the LFE group. In the HFE and LFE groups, Firmicutes and Cyanobacteria were negatively correlated, and Lactobacillus had medium to high negative correlations with most other genera. Functional prediction analysis showed that the gluconeogenesis I pathway was the most abundant differential metabolic pathway and was significantly altered in the LFE group. Moreover, although the microbial community structures were similar in the duodenum and ileum, the diversity of the microbial community was significantly higher in the duodenum than in the ileum. Pearson correlation analysis revealed that the phylum Chloroflexi and genera Acinetobacter, Pseudomonas, Bacillus and Neisseria were with coefficients <−0.3 or >0.3. In the ileum, Ruminococcus may be associated with HFE whereas Faecalibacterium may be associated with LFE. These findings may provide valuable foundations for future research on composition and diversity of intestinal microbes and provide insights into the roles of intestinal microbes in improving feed efficiency and the industrial economic benefits of yellow broilers.