Serum metabolome and gut microbiome alterations in broiler chickens supplemented with lauric acid

Activation of Antiviral Host Responses against Avian Influenza Virus and Remodeling of Gut Microbiota by rLAB Vector Expressing rIL-17A in Chickens

Low-pathogenic avian influenza virus (LPAIV) remains the most common subtype of type-A influenza virus that causes moderate to severe infection in poultry with significant zoonotic and pandemic potential. Due to high mutability, increasing drug resistance, and limited vaccine availability, the conventional means to prevent intra- or interspecies transmission of AIV is highly challenging. As an alternative to control AIV infections, cytokine-based approaches to augment antiviral host defense have gained significant attention. However, the selective application of cytokines is critical since unregulated expression of cytokines, particularly proinflammatory ones, can cause substantial tissue damage during acute phases of immune responses. Moreover, depending on the type of cytokine and its impact on intestinal microbiota, outcomes of cytokine-gut microflora interaction can have a critical effect on overall host defense against AIV infections. Our recent study demonstrated some prominent roles of chicken IL-17A (ChIL-17A) in regulating antiviral host responses against AIV infection, however, in an in vitro model. For more detailed insights into ChIL-17A function, in the present study, we investigated whether ChIL-17A-meditated elevated antiviral host responses can translate into effective immune protection against AIV infection in an in vivo system. Moreover, considering the role of gut health in fostering innate or local host responses, we further studied the contributory relationships between gut microbiota and host immunity against AIV infection in chickens. For this, we employed a recombinant lactic acid-producing bacterial (LAB) vector, Lactococcus lactis, expressing ChIL-17A and analyzed the in vivo functionality in chickens against an LPAIV (A/H9N2) infection. Our study delineates that mucosal delivery of rL. lactis expressing ChIL-17A triggers proinflammatory signaling cascades and can drive a positive shift in phylum Firmicutes, along with a marked decline in phylum Actinobacteriota and Proteobacteria, favoring effective antiviral host responses against AIV infection in chickens. We propose that ChIL-17A-mediated selective expansion of beneficial gut microbiota might form a healthy microbial community that augments the effective immune protection against AIV infections in chickens.

Prebiotic characteristics of degraded polysaccharides from Acanthopanax senticosus polysaccharide on broilers gut microbiota based on in vitro digestion and fecal fermentation

This study aimed to evaluate the effect of low molecular weight Acanthopanax polysaccharides on simulated digestion, probiotics, and intestinal flora of broilers in vitro. The experiments were carried out by H2O2-Vc degradation of Acanthopanax polysaccharides, in vitro simulated digestion to evaluate the digestive performance of polysaccharides with different molecular weights, in vitro probiotic evaluation of the probiotic effect of polysaccharides on lactobacilli and bifidobacteria, in vitro anaerobic fermentation and high-throughput sequencing of 16S rRNA genes to study the impact of Acanthopanax polysaccharides on the intestinal flora of broilers, and the effect of Acanthopanax polysaccharides on the short-chain fatty acids of intestines were determined by GC-MS method. The results showed that the molecular weight of Acanthopanax polysaccharide (ASPS) was 9,543 Da, and the molecular weights of polysaccharides ASPS-1 and ASPS-2 were reduced to 4,288 Da and 3,822 Da after degradation, and the particle sizes, PDIs, and viscosities were also significantly decreased. ASPS-1 has anti-digestive properties and better in vitro probiotic properties. The addition of ASPS-1 regulates the structure of intestinal microorganisms by regulating fecalibacterium to produce short-chain fatty acids, promoting the colonization of beneficial bacteria such as fecalibacterium, paraprevotella and diminishing the prevalence of detrimental bacteria such as Fusobacteria. Interestingly the ASPS-1 group found higher levels of Paraprevotella, which degraded trypsin in the gut, reducing inflammation, acted as a gut protector, and was influential in increasing the levels of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and total SCFAs in the fermented feces. Therefore, the degraded ASPS-1 can better regulate the structure of intestinal flora and promote the production of SCFAs, creating possibilities for its use as a potential prebiotic, which is conducive to the intestinal health of poultry.

Black soldier fly larvae oil (Hermetia illucens L.) calcium salt enhances intestinal morphology and barrier function in laying hens

This study aimed to determine the influence of black soldier fly larvae oil calcium salt (BSFLO-SCa) supplementation on performance, jejunal histomorphology and gene expression of tight junctions and inflammatory cytokines in laying hens. A total of 60 ISA Brown laying hens (40 wk of age) were divided into 3 treatment groups, including a control group fed a basal diet (T0) and basal diets supplemented with 1% (T1) and 2% (T2) of BSFLO-SCa. Each treatment group consisted of 5 replicates with 4 laying hens each. Results showed that 1% and 2% BSFLO-SCa supplementation significantly reduced (P < 0.05) feed conversion ratio (FCR), while egg weight (EW) increased (P < 0.05). The inclusion with 2% increased (P < 0.05) both egg production (HDA) and mass (EM). The addition of 1% and 2% BSFLO-SCa significantly increased (P < 0.05) villus height (VH) and villus width (VW), while crypt depth (CD) significantly increased (P < 0.05) with 2% BSFLO-SCa. The tight junction and gene expression of claudin-1 (CLDN-1), junctional adhesion molecules-2 (JAM-2), and occludin (OCLN) were significantly upregulated (P < 0.05) with 2% BSFLO-SCa. The pro-inflammatory cytokines and gene expression of interleukin-6 (IL-6) was significantly downregulated (P < 0.05) with the addition of BSFLO-SCa, while gene expression of interleukin-18 (IL-18), toll-like receptor 4 (TLR-4), and tumor necrosis factor-α (TNF-α) were downregulated with 2% BSFLO-SCa. On the other hand, the anti-inflammatory cytokines and gene expression of interleukin-13 (IL-13) and interleukin-10 (IL-10) were significantly upregulated (P < 0.05) at 2% BSFLO-SCa. In conclusion, dietary supplementation with 2% BSFLO-SCa improved productivity, intestinal morphology and integrity by upregulating tight junction-related protein of gene expression of laying hens. In addition, supplementation with BSFLO-SCa enhanced intestinal immune responses by upregulating anti-inflammatory and downregulating pro-inflammatory cytokine gene expression.

Effects of different black soldier fly larvae products on slow-growing broiler performance and carcass characteristics

Black soldier fly (BSF) larvae have gained significant attention as ingredients for poultry feed to improve value chain circularity and sustainability. Black soldier fly larvae contain bioactive compounds which can potentially improve broiler health and thereby performance. However, the functionality of bioactive compounds likely depends on how larvae are processed prior to feeding and to which extent larvae products are included in the diet. This may explain the variable results reported in literature on broiler performance and carcass characteristics when feeding them different types of BSF larvae products at different inclusion levels. Therefore, the present research aimed to investigate the effects of different BSF larvae products and inclusion levels in diets on performance and carcass characteristics of slow-growing broilers. The experiment started with 1,728 one-day-old slow-growing male broilers (Hubbard JA757). Nine dietary treatments were used, each replicated eight times. One group of broilers was given a control diet. The following BSF larvae products were investigated: live larvae, a combination of BSF larvae meal and oil mimicking the nutritional composition of the live larvae, and BSF larvae meal and oil separately. All insect products were tested at two inclusion levels. All diet programs were nutritionally comparable (isoenergetic and based on balanced levels of digestible essential amino acids). During the 7-wk trial, several performance parameters and carcass characteristics were measured. The results show that comparable or better broiler performance was achieved with the inclusion of BSF larvae products in the diets compared to the control. Based on the feed conversion ratio (FCR), the unprocessed larvae product and the highest inclusion level led to the most favorable results. Carcass characteristics remained unchanged when BSF larvae products were used in the diets compared to the control group, indicating favorable production output. The BSF larvae products investigated seem suitable feed ingredients for broilers at the current levels tested, generating performance benefits.

Isolation and in vitro assessment of chicken gut microbes for probiotic potential

Poultry production occupies an important place in the economy of any country. High broiler production in recent years has badly affected its profitability due to bad feed quality, excessive use of chemotherapeutic agents, emergence of diverse pathogens, and the deficiencies in management practices during rearing cycle. Microbiological improvement of the meat quality using potential probiotics can be beneficial for broiler farming. Present study was initiated to isolate chicken gastrointestinal tract (GIT) bacteria with probiotic potential. To isolate probiotics from chicken gut, alimentary canal of chickens of known sizes and ages was suspended in ringers soln. Under shaking conditions for overnight followed by serial dilutions of ringers soln. Bacterial isolates were analyzed via growth curve analysis, biochemical testing using RapID™ NF Plus Panel kit, molecular characterization, antimicrobial activity assay, antibiotic sensitivity assay, GIT adherence assay, bile salt and gastric acid resistant assay, and cholesterol assimilation assay. Four bacteria isolated in present study were identified as Limosilactobacillus antri strain PUPro1, Lactobacillus delbrueckii strain PUPro2, Lacticaseibacillus casei strain PUPro3, and Ligilactobacillus salivarius strain PUPro4. L. delbrueckii strain PUPro2 grew extremely fast. All isolates exhibited exceptional resistance to increasing concentrations of NaCl and bile salts with value of p >0.5. L. delbrueckii strain PUPro2 adhered to chicken ileum epithelial cells and demonstrated the highest viable counts of 320 colony forming units (CFUs). Antagonistic action was found in all isolates against P. aeruginosa, B. subtilis, B. proteus, and S. aureus, with value of p >0.5. Antibiotic susceptibility testing showed sensitivity to all the antibiotics used. Cholesterol assimilation was detected in all bacteria, with values ranging from 216.12 to 192.2 mg/dL. All isolates exhibited γ-hemolysis. In future, these bacteria might be tested for their impact on broilers meat quality and growth and can be recommended for their use as supplements for broilers diet with positive impact on poultry production.

Novel Lauric Acid-Butyric Structural Lipid Inhibits Inflammation: Small Intestinal Microbes May Be Important Mediators

SCOPE

Butyric acid (C4) and lauric acid (C12) are recognized as functional fatty acids, while the health benefits of the structural lipids they constitute remain unclear.

METHODS AND RESULTS

In this study, lauric acid-butyric structural lipid (SLBL ) is synthesized through ultrasound-assisted enzyme-catalyzed acidolysis and its health benefits are evaluated in a high-fat diet-induced obesity mouse model. SLBL and its physical mixture (MLBL ) do not significantly inhibit obesity in mice. However, SLBL treatment increases the ratio of n3/n6 fatty acids in the liver and improves obesity-induced hepatic lipid metabolism disorders. Furthermore, the expression of liver pro-inflammatory cytokines (interleukin [IL]-6, IL-1β, TNF-α) are significantly suppressed by SLBL , while the expression of anti-inflammatory cytokine (IL-10) is increased. Moreover, SLBL ameliorates the dysbiosis of small intestinal microbes induced by high-fat diet and regulates microbial community structure to be close to the control group. Especially, SLBL significantly alleviates the high-fat diet-induced decrease in Dubosiella and Bifidobacterium abundance. Correlation analysis reveals that SLBL treatment increases the abundance of microorganisms with potential anti-inflammatory function and decreases the abundance of potentially pathogenic bacteria.

CONCLUSION

In all, small intestinal microbes may be a significant bridge for the positive anti-inflammatory effects of SLBL , while the exact mechanism remains to be clarified.

Therapeutic effect of a self-made herbal formula on a multi-drug resistant Eimeria tenella isolate infection in broiler chickens

In-feed prophylactic chemotherapy is widely considered the mainstay of avian coccidiosis control, while serious drug resistance strictly restricts its application. Confronted with the urgent need for an alternative strategy, a traditional Chinese medicine formula (TCMF) was developed. Meanwhile, its potential to iron out complicated clinical coccidiosis was scrutinized in vivo with a field-isolated multi-drug resistant Eimeria tenella (E. tenella) isolate. Birds were inoculated with 5 × 104 sporulated oocysts and administrated with TCMF supplementation in water from 72 h post-infection to the end of the experiment, diclazuril (DIC) was set as a positive control. As a result, TCMF intervention reduced oocyst shedding, cecal lesion and mortality, and enhanced body weight gain. According to the above, anticoccidial index (ACI) was calculated and TCMF exerted a moderate anticoccidial activity. Besides, macroscopic, histopathological, and ultrastructural observations revealed the safeguarding effects of TCMF on E. tenella-induced cecal injury. Following, TCMF treatment presented an obvious inhibition effect on E. tenella caused oxidative stress and inflammatory response. Moreover, TCMF supplementation restored the cecal flora abundance and diversity, reduced the colonization of harmful bacteria, and increased the probiotics abundance. In conclusion, TCMF exhibited a moderate anticoccidial effect along with alleviating E. tenella-induced cecal injury, redox imbalance, and inflammatory response which may be associated with the microflora modulatory effect.

Inclusion of up to 20% Black Soldier Fly larvae meal in broiler chicken diet has a minor effect on caecal microbiota

Background

The Black Soldier Fly larvae (BSFL) are a source of nutrients and bioactive compounds in broiler diets. Some components of the BSFL may serve as a prebiotic or may impact the intestinal microbiota of the broilers by other modes of action, which in turn can affect the health and performance of broilers. Here, we investigate the impact of up to 20% BSFL in broiler diets on the diversity and composition of the broiler's microbiota.

Methods

Four hundred broilers were fed five iso-nutritious experimental diets with increasing levels of BSFL meal reaching 0%, 5%, 10%, 15%, 20% in the finisher diets. Eight caecal content samples coming from each of the eight replicates per treatment were collected at two time points (day 21 and day 42) for DNA extraction and sequencing of the V3-V4 regions using Illumina MiSeq 2 × 300 bp pair-end sequencing with 341f and 805r primers. Analysis of variance and Spearman's correlation were performed, while QIIME2, DADA2, and Calypso were used for data analysis.

Results

When broilers were 21 days of age, the abundance of two groups of sequence variants representing Enterococcus and unclassified Christensenellaceae was significantly lower (p-value = 0.048 and p-value = 0.025, respectively) in the 20% BSFL group compared to the 0% BSFL group. There was no relevant alteration in the microbiota diversity at that stage. On day 42, the Spearman correlation analysis demonstrated that the sequence variants representing the genus Coprococcus showed a negative relationship with the BSFL inclusion levels (p-value = 0.043). The sequence variants representing the genus Roseburia and Dehalobacterium demonstrated a positive relationship with the BSFL dietary inclusion (p-value = 0.0069 and p-value = 0.0034, respectively). There was a reduction in the dissimilarity index (ANOSIM) caused by the 20% BSFL dietary inclusion.

Conclusion

The addition of up to 20% BSFL in broiler diets did not affect the overall caeca microbiota diversity or composition at day 21. On day 42, there was a reduction in the beta diversity caused by the 20% BSFL dietary inclusion. The abundance of the bacterial group Roseburia was increased by the BSFL dietary inclusion, and it may be beneficial to broiler immunity and performance.

Heat stress exposure cause alterations in intestinal microbiota, transcriptome, and metabolome of broilers

Introduction

Heat stress can affect the production of poultry through complex interactions between genes, metabolites and microorganisms. At present, it is unclear how heat stress affects genetic, metabolic and microbial changes in poultry, as well as the complex interactions between them.

Methods

Thus, at 28  days of age a total of 200 Arbor Acres broilers with similar body weights were randomly divided into the control (CON) and heat stress treatment (HS). There were 5 replicates in CON and HS, respectively, 20 per replication. From the 28-42  days, the HS was kept at 31 ± 1°C (9:00-17:00, 8 h) and other time was maintained at 21 ± 1°C as in the CON. At the 42nd day experiment, we calculated the growth performance (n = 8) of broilers and collected 3 and 6 cecal tissues for transcriptomic and metabolomic investigation and 4 cecal contents for metagenomic investigation of each treatment.

Results and discussion

The results indicate that heat stress significantly reduced the average daily gain and body weight of broilers (value of p < 0.05). Transcriptome KEGG enrichment showed that the differential genes were mainly enriched in the NF-kB signaling pathway. Metabolomics results showed that KEGG enrichment showed that the differential metabolites were mainly enriched in the mTOR signaling pathway. 16S rDNA amplicon sequencing results indicated that heat stress increased the relative abundance of Proteobacteria decreased the relative abundance of Firmicutes. Multi-omics analysis showed that the co-participating pathway of differential genes, metabolites and microorganisms KEGG enrichment was purine metabolism. Pearson correlation analysis found that ornithine was positively correlated with SULT1C3, GSTT1L and g_Lactobacillus, and negatively correlated with CALB1. PE was negatively correlated with CALB1 and CHAC1, and positively with g_Alistipes. In conclusion, heat stress can generate large amounts of reactive oxygen and increase the types of harmful bacteria, reduce intestinal nutrient absorption and antioxidant capacity, and thereby damage intestinal health and immune function, and reduce growth performance indicators. This biological process is manifested in the complex regulation, providing a foundational theoretical basis for solving the problem of heat stress.

Evaluation of dynamic effects of dietary medium-chain monoglycerides on performance, intestinal development and gut microbiota of broilers in large-scale production

Medium-chain monoglycerides (MG) have been reported to affect the productive performance, gut microbiota and health of broiler chickens reared in ideal experimental conditions at home and abroad. However, the effects of MG on performance, intestinal development and gut microbiota of chickens in large-scale farms during different feed stages remain unknown. The present study was conducted on a modern farm with a total of 12,000 yellow feathered broiler chicks that were randomly allotted to 2 groups (1000 chicks/replicate, 6 replicates/group) for a 70-day trial. The control group (CON group) received a basal diet, and the treated group (MG group) was fed a basal diet containing 300 mg/kg mixed MG. The results revealed that dietary MG significantly (P < 0.05) increased the body weight and average feed intake, but notably reduced the feed conversion and mortality of chickens in large-scale production during the starter phase. The villus height of the duodenum in the MG group at 1, 2 and 7 wk of age increased notably, and the villus height to crypt depth ratio at 1, 2, 5 and 10 wk of age was improved. Dietary MG decreased the serum insulin content of chickens at 5, 7 and 10 wk of age, and decreased the serum lipopolysaccharide at 3 and 7 wk of age. The triglyceride level of chickens at 3, 5 and 10 wk of age and the low-density lipoprotein cholesterol level of chickens at 7 and 10 wk of age in the MG group decreased notably, while the high-density lipoprotein cholesterol increased significantly. Moreover, MG supplementation selectively increased the relative abundance of genus Bacteroides (family Bacteroidaceae) and Lachnospiraceae_NK4A136_group, but decreased the content of genus Rikenellaceae_RC9_gut_group, Collinsella and family Barnesiellaceae in the cecum of chickens at 3, 7 and 10 wk of age. Conclusively, these findings showed that dietary MG notably enhanced chicken performance, health and feed nutrient utilization at early ages by regulating gut microbiota, intestinal development and serum biochemical indices.

Integrated multi-omics reveals the beneficial role of chlorogenic acid in improving the growth performance and immune function of immunologically stressed broilers

Intensive production can cause immunological stress in commercial broilers. Chlorogenic acid (CGA) regulates the intestinal microbiota, barrier function, and immune function in chickens. As complex interrelations regulate the dynamic interplay between gut microbiota, the host, and diverse health outcomes, the aim of this study was to elucidate the immunoregulatory mechanisms of CGA using multi-omics approaches. A total of 240 one-day-old male broilers were assigned to a 2 × 2 factorial design with 2 CGA levels (0 or 500 mg/kg) either with or without dexamethasone (DEX) injection for a 21-day experimental period. Therefore, there were 4 dietary treatments: control, DEX, CGA, and DEX + CGA, with 6 replicates per treatment. CGA supplementation improved (P < 0.05) growth performance, jejunal morphology, jejunal barrier function, and immune function in DEX-treated broilers. Moreover, in DEX + CGA-treated broilers, the increase in gut microbiome diversity (P < 0.05) was consistent with a change in taxonomic composition, especially in the Clostridiales vadin BB60_group. Additionally, the levels of short-chain fatty acids increased remarkably (P < 0.01) after CGA supplementation. This was consistent with the Kyoto Encyclopedia of Genes and Genomes analysis results that the "pyruvate fermentation to butanoate" pathway was more enriched (P < 0.01) in the DEX + CGA group than in the DEX group. Proteomics revealed that CGA treatment increased the expression of several health-promoting proteins, thymosin beta (TMSB4X) and legumain (LGMN), which were verified by multiple reaction monitoring. Metabolomics revealed that CGA treatment increased the expression of health-promoting metabolites (2,4-dihydroxy benzoic acid and homogentisic acid). Proteomic and metabolic analyses showed that CGA treatment regulated the peroxisome proliferator-activated receptor (PPAR) and mitogen-activated protein kinase (MAPK) pathways. Western blotting results support these findings. Pearson's correlation analyses showed correlations (P < 0.01) between altered immune function, jejunal barrier function, different microbiota, proteins, and metabolites parameters. Overall, our data indicate that CGA treatment increased growth performance and improved the immunological functions of DEX-treated broilers by regulating gut microbiota and the PPAR and MAPK pathways. The results offer novel insights into a CGA-mediated improvement in immune function and intestinal health.

Insects as an alternative protein source for poultry nutrition: a review

This review summarizes the most relevant scientific literature related to the use of insects as alternative protein sources in poultry diets. The black soldier fly, the housefly, the beetle, mealworms, silkworms, earthworms, crickets, and grasshoppers are in the spotlight because they have been identified as an important future source of sustainable animal proteins for poultry feeding. Insect meals meet poultry requirements in terms of nutritional value, essential amino acid composition, nutrient digestibility, and feed acceptance. Furthermore, they are enriched with antimicrobial peptides and bioactive molecules that can improve global health. Results from poultry studies suggest equivalent or enhanced growth performances and quality of end-products as compared to fish meal and soybean meal. To outline this body of knowledge, this article states established threads of research about the nutrient profiles and the digestibility of insect meals, their subsequent effects on the growth and laying performances of poultry as well as the quality of meat, carcass, and eggs. To fully exploit insect-derived products, the effects of insect bioactive molecules (antimicrobial peptides, fatty acids, and polysaccharides) were addressed. Furthermore, as edible insects are likely to take a meaningful position in the feed and food chain, the safety of their derived products needs to be ensured. Some insights into the current knowledge on the prevalence of pathogens and contaminants in edible insects were highlighted. Finally, the effect of insect farming and processing treatment on the nutritive value of insect larvae was discussed. Our overview reveals that using insects can potentially solve problems related to reliance on other food sources, without altering the growth performances and the quality of meat and eggs.

Effects of Traditional Chinese Herbal Feed Additive on Production Performance, Egg Quality, Antioxidant Capacity, Immunity and Intestinal Health of Laying Hens

Chinese herbs have been used as feed additives in animal production. This study investigated the effects of a Chinese herbal feed-additive (TCM, which contained Elsholtzia ciliate, Atractylodes macrocephala, Punica granatum pericarpium, and Cyperus rotundus) on the production performance, egg quality, antioxidant capacity, immunity, and intestinal health of Roman laying hens. A total of 720 28-week-old hens were randomly allotted to three groups with six replicates of forty hens each. The groups were fed a basal diet (CON group), a basal diet with 50 mg/kg zinc bacitracin (ABX group), or a basal diet with 400 mg/kg TCM (TCM group) for 56 days. The results showed that the TCM group increased egg production, egg mass, albumen height, and Haugh unit compared with the CON group (p < 0.05). There were no significant differences in egg weight, feed intake, feed conversion rate, and eggshell strength among all three groups (p > 0.05). Compared with the CON group, the TCM group enhanced the activities of glutathione peroxidase, total antioxidant capacity, and superoxide dismutase in serum and liver, and reduced malondialdehyde content (p < 0.05). The TCM also increased the levels of interleukin-2, interferon-γ, immunoglobulin A, immunoglobulin M, and immunoglobulin G, and decreased the levels of interleukin-6 and interleukin-8 compared with the CON group (p < 0.05). Furthermore, the TCM group increased jejunal goblet cell density and decreased ileal crypt depth and lymphocyte density compared with the CON group (p < 0.05). The results of 16S rRNA demonstrated that the TCM can change the diversity and composition of intestinal microbiota. At the phylum level, the abundance of Bacteroides increased while that of Firmicutes decreased in the TCM group (p > 0.05). At the genus level, the abundance of Lactobacillus, Rikenellaceae_RC9_gut_group, and Phascolarctobacterium increased while that of Bacteroides and unclassified_o__Bacteroidales decreased in the TCM group (p > 0.05). The effects of ABX were weaker than those of the TCM. In conclusion, the TCM has positive effects on production performance and the intestinal health of hens.

Effects of a combination of lauric acid monoglyceride and cinnamaldehyde on growth performance, gut morphology, and gut microbiota of yellow-feathered broilers

A total of 480 one-day-old male yellow-feathered broilers were randomly divided into 4 groups with 6 replicates of 20 chicks per replicate. A basal diet was administered to the control group (CON), whereas CML350, CML500, and CML1000 groups were fed with basal diet supplemented with 350, 500, and 1,000 mg/kg of lauric acid monoglyceride and cinnamaldehyde complex, respectively. However, adding 500 mg/kg of lauric acid monoglyceride and cinnamaldehyde complex improved weight gain (P < 0.01), enhanced intestinal morphology, increased serum total protein and albumin content, and total antioxidant capacity (P < 0.01), and significantly increased the Chao1 and Ace indices (P < 0.01), indicating an increase in the richness of the gut microbiota. At the phylum level, CML500 group reduced the abundance of Fusobacteriota at 21 d and Proteobacteria at 42 d (P < 0.01). At the genus level, CML500 group increased the abundance of Faecalibacterium and Alistipes at 42 d (P < 0.01) and decreased the abundance of Escherichia-Shigella (P < 0.01). At the species level, CML500 group reduced the abundance of Escherichia coli at 42 d (P < 0.01) and increased the abundance of Alistipes_sp_CHKCI003 at 42 d (P < 0.01). According to these results, adding 500 mg/kg of lauric acid monoglyceride and cinnamaldehyde complex in feed can improve the growth performance, intestinal morphology, and gut microbiota of yellow-feathered broilers.

Effects of Major Families of Modulators on Performances and Gastrointestinal Microbiota of Poultry, Pigs and Ruminants: A Systematic Approach

Considering the ban on the use of antibiotics as growth stimulators in the livestock industry, the use of microbiota modulators appears to be an alternative solution to improve animal performance. This review aims to describe the effect of different families of modulators on the gastrointestinal microbiota of poultry, pigs and ruminants and their consequences on host physiology. To this end, 65, 32 and 4 controlled trials or systematic reviews were selected from PubMed for poultry, pigs and ruminants, respectively. Microorganisms and their derivatives were the most studied modulator family in poultry, while in pigs, the micronutrient family was the most investigated. With only four controlled trials selected for ruminants, it was difficult to conclude on the modulators of interest for this species. For some modulators, most studies showed a beneficial effect on both the phenotype and the microbiota. This was the case for probiotics and plants in poultry and minerals and probiotics in pigs. These modulators seem to be a good way for improving animal performance.

Physiological and Transcriptomic Analyses of the Effects of Exogenous Lauric Acid on Drought Resistance in Peach (Prunus persica (L.) Batsch)

Peach (Prunus persica (L.) Batsch) is a fruit tree of economic and nutritional importance, but it is very sensitive to drought stress, which affects its growth to a great extent. Lauric acid (LA) is a fatty acid produced in plants and associated with the response to abiotic stress, but the underlying mechanism remains unclear. In this study, physiological analysis showed that 50 ppm LA pretreatment under drought stress could alleviate the growth of peach seedlings. LA inhibits the degradation of photosynthetic pigments and the closing of pores under drought stress, increasing the photosynthetic rate. LA also reduces the content of O₂^-, H₂O₂, and MDA under drought stress; our results were confirmed by Evans Blue, nitroblue tetrazolium (NBT), and DAB(3,3-diaminobenzidine) staining experiments. It may be that, by directly removing reactive oxygen species (ROS) and improving enzyme activity, i.e., catalase (CAT) activity, peroxidase (POD) activity, superoxide dismutase (SOD) activity, and ascorbate peroxidase (APX) activity, the damage caused by reactive oxygen species to peach seedlings is reduced. Peach seedlings treated with LA showed a significant increase in osmoregulatory substances compared with those subjected to drought stress, thereby regulating osmoregulatory balance and reducing damage. RNA-Seq analysis identified 1876 DEGs (differentially expressed genes) in untreated and LA-pretreated plants under drought stress. In-depth analysis of these DEGs showed that, under drought stress, LA regulates the expression of genes related to plant-pathogen interaction, phenylpropanoid biosynthesis, the MAPK signaling pathway, cyanoamino acid metabolism, and sesquiterpenoid and triterpenoid biosynthesis. In addition, LA may activate the Ca²⁺ signaling pathway by increasing the expressions of CNGC, CAM/CML, and CPDK family genes, thereby improving the drought resistance of peaches. In summary, via physiological and transcriptome analyses, the mechanism of action of LA in drought resistance has been revealed. Our research results provide new insights into the molecular regulatory mechanism of the LA-mediated drought resistance of peach trees.

Effects of Compound Probiotics on Cecal Microbiota and Metabolome of Swine

Complex probiotics are made from various single probiotics mixed in scientific formula. The long-term intake of different probiotics is beneficial to maintain the intestinal microecological balance, inhibiting harmful pathogenic flora and facilitating organism health. Based on the limited research on intestinal flora and related metabolites after the long-term intake of the probiotic complex, in this study, 16S rRNA gene sequencing and untargeted metabolomics were used to further investigate the effects of the probiotic complex on the intestinal flora and metabolome of pigs. The results demonstrated that the content of flora in the intestinal tract or metabolites of pigs varied greatly and was related to cellular metabolic pathways after the long-term feeding of complex probiotics. This study provides a valuable theoretical basis for farmers to raise pigs scientifically and healthily.

Integrated Serum Metabolome and Gut Microbiome to Decipher Chicken Amino Acid Improvements Induced by Medium-Chain Monoglycerides

Chicken muscle yield and amino acid composition improvements with medium-chain monoglyceride (MG) supplementation were reported by previous studies, but the underlying mechanism was uncertain. This study aimed to decipher chicken amino acid improvements induced by medium-chain monoglycerides in the views of metabolomics, gene expression, and the gut microbiome. Newly hatched chicks (12,000 chicks) were weighed and randomly divided into two flocks, each with six replicates (1000 chicks per replicate), and fed a basal diet (the control group, CON) or a basal diet enriched with 300 mg/kg MG (the treated group, MG). Results demonstrated that MGs significantly increased the chicken flavor and essential and total amino acids. The serum amino acids and derivatives (betaine, l-leucine, l-glutamine, 1-methylhistide), as well as amino acid metabolism pathways in chickens, were enhanced by MG supplementation. Gene expression analysis exhibited that dietary MGs could improve muscle protein synthesis and cell growth via the mTOR/S6K1 pathway. Dietary MGs enhanced the cecal amino acid metabolism by selectively increasing the proportion of genera Lachnospiraceae_NK4A136_group and Bacteroides. Conclusively, the present study demonstrated that dietary MGs improved chicken amino acid composition via increasing both gut amino acid utilization and muscle amino acid deposition.

How to employ metabolomic analysis to research on functions of prebiotics and probiotics in poultry gut health?

Gut health can be considered one of the major, manageable constituents of the animal immunity and performance. The fast spread of intestinal diseases, and increase of antimicrobial resistance have been observed, therefore the intestinal health has become not only economically relevant, but also highly important subject addressing the interest of public health. It is expected, that the strategies to control infections should be based on development of natural immunity in animals and producing resilient flocks using natural solutions, whilst eliminating antibiotics and veterinary medicinal products from action. Probiotics and prebiotics have been favored, because they have potential to directly or indirectly optimize intestinal health by manipulating the metabolism of the intestinal tract, including the microbiota. Studying the metabolome of probiotics and gut environment, both in vivo, or using the in vitro models, is required to attain the scientific understanding about the functions of bioactive compounds in development of gut health and life lasting immunity. There is a practical need to identify new metabolites being the key bioactive agents regulating biochemical pathways of systems associated with gut (gut-associated axes). Technological advancement in metabolomics studies, and increasing access to the powerful analytical platforms have paved a way to implement metabolomics in exploration of the effects of prebiotics and probiotics on the intestinal health of poultry. In this article, the basic principles of metabolomics in research involving probiotics and probiotics are introduced, together with the overview of existing strategies and suggestions of their use to study metabolome in poultry.

Suitability of Hermetia illucens larvae meal and fat in broiler diets: effects on animal performance, apparent ileal digestibility, gut histology, and microbial metabolites

Background

The possibility of partially replacing soybean meal (SBM) with Hermetia illucens (HI) defatted larvae meal in broiler nutrition has frequently been suggested. For sustainability reasons, however, the larvae fat produced during defatting should also be used and could be particularly beneficial regarding gut health due to its fatty acid composition. To evaluate the suitability of HI larvae as protein and fat source, a 2 × 3 factorial arrangement with two types of protein, i.e. SBM (S) or SBM and 15% of its crude protein replaced by HI larvae meal (L), and three levels of fat sources, namely 0 (0 L), 50% (50 L) or 100% HI larvae fat (100 L) at the expense of soybean oil was applied.

Results

In the starter phase, an interaction showed higher body weight (BW), average daily gain (ADG) and improved feed conversion ratio (FCR) if 50% or 100% HI larvae fat was fed with HI larvae meal. Moreover, BW, ADG and FCR improved when feeding HI larvae meal as protein source. Additionally, we observed an increased average daily feed intake in the grower, finisher, and overall phase in the L groups and an improved FCR in 0 L compared to 50 L groups during the overall period. Regarding apparent ileal digestibility, HI larvae meal feeding increased dry matter, organic matter, and fat digestibility. Feeding HI larvae meal as protein source decreased the concentrations of agmatine, spermidine, spermine and ammonia in the caecal digesta, whereas fat source affected agmatine with higher concentrations in 50 L compared to 0 L in the colonic digesta. In contrast, caecal ethanolamine concentrations increased in HI larvae meal groups compared to SBM. Caecal butyric acid concentrations decreased with HI larvae meal feeding. An interaction was found for the jejunal villus area, being higher in L + 100 L compared to S + 100 L. Furthermore, L groups had greater villus width.

Conclusions

A partial replacement of SBM with HI larvae meal and soybean oil with HI larvae fat in broiler diets without impairing animal performance or gut health seems possible. Feeding HI larvae meal affected broiler performance positively in the starter phase and improved apparent ileal digestibility.

A Probabilistic Structural Equation Model to Evaluate Links between Gut Microbiota and Body Weights of Chicken Fed or Not Fed Insect Larvae

Simple Summary

Feeding poultry with insects could reduce production costs, but the impact of this diet on their gut microbiota and growth is little known because the network of relationships between their weights, the composition of their microbiota and their diet is complex and potentially biased by confounding factors (such as the gut compartment, age and sex of the birds). In this study, we were able to unravel these relationships in local breed chickens fed or not fed with black soldier fly larvae thanks to a technique of artificial intelligence (the probabilistic structural equation model). Bacteria were grouped into few entities with distinctive metabolic attributes and were probably linked nutritionally. Birds’ age influenced body weights and bacterial composition. The proposed methodology was thus able to simplify the complex dependencies among bacteria present in the gut and to highlight links potentially important in the response of chicken to insect feed.

Abstract

Feeding chicken with black soldier fly larvae (BSF) may influence their rates of growth via effects on the composition of their gut microbiota. To verify this hypothesis, we aim to evaluate a probabilistic structural equation model because it can unravel the complex web of relationships that exist between the bacteria involved in digestion and evaluate whether these influence bird growth. We followed 90 chickens fed diets supplemented with 0%, 5% or 10% BSF and measured the strength of the relationship between their weight and the relative abundance of bacteria (OTU) present in their cecum or cloaca at 16, 28, 39, 67 or 73 days of age, while adjusting for potential confounding effects of their age and sex. Results showed that OTUs (62 genera) could be combined into ten latent constructs with distinctive metabolic attributes. Links were discovered between these constructs that suggest nutritional relationships. Age directly influenced weights and microbiotal composition, and three constructs indirectly influenced weights via their dependencies on age. The proposed methodology was able to simplify dependencies among OTUs into knowledgeable constructs and to highlight links potentially important to understand the role of insect feed and of microbiota in chicken growth.

Effect of functional diets on intestinal microbiota and resistance to Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease (AHPND) of Pacific white shrimp (Penaeus vannamei)

AIMS

The present study evaluated the effect of four functional diets and a reference diet on the survival and intestinal bacterial community of shrimp Penaeus vannamei infected with AHPND.

METHODS AND RESULTS

After 42 days of feeding trail, shrimp were inoculated with a Vibrio parahaemolyticus (CIB-0018-3) carrying the plasmid encoding for the PirAB toxins responsible for AHPND. After 120 h post-infection (hpi), shrimp fed with a diet containing 2% of a mix with Curcuma longa and Lepidium meyenii (TuMa) and a diet containing 0.2% of vitamin C (VitC) showed a significantly higher survival (85%) compared to the remaining treatments (50-55%) (p<0.05). Infected shrimp fed with TuMa diet, showed a significant reduction of Vibrionales; and VitC diet promoted an increase of Alteromonadales.

CONCLUSIONS

Our findings suggest that the TuMa diet conferred protection against AHPND and could be attributed to a combined effect of antibacterial properties against Vibrionales, and promoting a desirable bacterial community in the shrimp intestine, while the VitC diet protection could be attributed to their antioxidant capacity and in a lower proportion to a bacterial modulation in shrimp gut.

SIGNIFICANCE AND IMPACT OF THE STUDY

Acute Hepatopancreatic Necrosis Disease (AHPND) is a devastating disease that significantly affects aquaculture production of shrimps. Therefore, the use of functional diets that promotes resistance to AHPND, represents a valuable tool to reduce the mortality of farmed shrimp.

Integrating Serum Metabolome and Gut Microbiome to Evaluate the Benefits of Lauric Acid on Lipopolysaccharide- Challenged Broilers

Lauric acid (LA) is a crucial medium-chain fatty acid (MCFA) that has many beneficial effects on humans and animals. This study aimed to investigate the effects of LA on the intestinal barrier, immune functions, serum metabolism, and gut microbiota of broilers under lipopolysaccharide (LPS) challenge. A total of 384 one-day-old broilers were randomly divided into four groups, and fed with a basal diet, or a basal diet supplemented with 75 mg/kg antibiotic (ANT), or a basal diet supplemented with 1000 mg/kg LA. After 42 days of feeding, three groups were intraperitoneally injected with 0.5 mg/kg Escherichia coli- derived LPS (LPS, ANT+LPS and LA+LPS groups) for three consecutive days, and the control (CON) group was injected with the same volume of saline. Then, the birds were sacrificed. Results showed that LA pretreatment significantly alleviated the weight loss and intestinal mucosal injuries caused by LPS challenge. LA enhanced immune functions and inhibited inflammatory responses by upregulating the concentrations of immunoglobulins (IgA, IgM, and IgY), decreasing IL-6 and increasing IL-4 and IL-10. Metabolomics analysis revealed a significant difference of serum metabolites by LA pretreatment. Twenty-seven serum metabolic biomarkers were identified and mostly belong to lipids. LA also markedly modulated the pathway for sphingolipid metabolism, suggesting its ability to regulate lipid metabolism. Moreover,16S rRNA analysis showed that LA inhibited LPS-induced gut dysbiosis by altering cecal microbial composition (reducing Escherichia-Shigella, Barnesiella and Alistipes, and increasing Lactobacillus and Bacteroides), and modulating the production of volatile fatty acids (VFAs). Pearson’s correlation assays showed that alterations in serum metabolism and gut microbiota were strongly correlated to the immune factors; there were also strong correlations between serum metabolites and microbiota composition. The results highlight the potential of LA as a dietary supplement to combat bacterial LPS challenge in animal production and to promote food safety.