Dietary organic acids ameliorate high stocking density stress-induced intestinal inflammation through the restoration of intestinal microbiota in broilers

Yeast culture promotes albumen quality by improving magnum protein secretion and intestinal microbiota in aged laying hens

BACKGROUND

The supplementation of yeast culture (YC) has the potential to enhance egg quality in laying hens. However, most studies focus on eggshell quality. This study aimed to investigate the effects of dietary YC supplementation on the production performance, albumen quality, protein synthesis or secretion of the magnum and the cecal microbiota content of laying hens.

RESULTS

The results showed that dietary YC supplementation increased albumen height and Haugh unit (P ≤ 0.05). Besides, dietary 100 g kg-1 YC addition increased significantly the ridge width of the magnum and the relative expression of SEC23A in the magnum and decreased significantly the relative expression of OVOB in the magnum (P ≤ 0.05). Furthermore, the abundances of Butyricicoccus, Alistipes and Flavonifractor were increased significantly by 100 g kg-1 YC supplementation (P ≤ 0.05). The diet supplemented with 100 g kg-1 YC significantly increased the butyric acid and isobutyric acid of the cecum.

CONCLUSION

Dietary supplementation with YC improved protein secretion in the magnum and enhanced the beneficial cecal microbiota, thus improving the albumen quality of laying hens. © 2025 Society of Chemical Industry.

Aspirin Eugenol Ester Modulates the Hypothalamus Transcriptome in Broilers Under High Stocking Density

Broilers grown in a high-density (HD) stocking environment may experience intense competition that may adversely affect their growth relative to animals reared at a normal density (ND). The growth performance of HD broilers is increased by aspirin eugenol ester (AEE), although the mechanism by which this compound modulates hypothalamus-regulated feeding behavior is unclear. The aims of this study were to determine the effects of including AEE in the basal diet on the hypothalamic transcriptome and to examine in parallel the impact of these modifications on broiler production performance in HD conditions. Three hundred sixty one-day-old male Arbor Acres broilers were randomly divided into four groups: an ND group (14 broilers/m2), HD group (22 broilers/m2), ND-AEE group, and HD-AEE group. Each treatment group had 10 replicates, with 7 broilers per replicate in the ND and ND-AEE groups and 11 broilers per replicate in the HD and HD-AEE groups. Broiler growth performance was monitored, and hypothalamus samples were collected for transcriptome analysis on day 28. The HD group exhibited a reduced body weight (p < 0.01) at this timepoint compared to the ND group. However, the addition of AEE significantly improved average daily feed intake, average daily gain, and feed conversion ratio in the HD group from days 22 to 28 compared to the HD group without AEE (p < 0.05). The transcriptome results showed that 20 signaling pathways were commonly enriched among the groups (ND vs. HD, HD vs. HD-AEE). Several potential candidate genes were identified as involved in chicken central nervous system development and regulation of feed intake. Thus, the current study provides new insights into hypothalamic transcription patterns that are associated with the ameliorative effects of AEE in HD broilers.

Beneficial effects of ε-polylysine on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet

This study was conducted to investigate the effects of dietary ε-polylysine supplementation on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet. A total of 960 one-day-old yellow-feathered broilers were randomly allocated into six groups with eight replicates and 20 birds per replicate. Birds in the six groups were fed a lysine-deficient basal diet (-0.20 % lysine, NC) or basal diets supplemented with 0.20 % L-lysine hydrochloride (normal lysine level, PC) or varying levels (0.10 %, 0.20 %, 0.30 %, or 0.40 %) of ε-polylysine hydrochloride for 10 weeks. Results showed that compared with the NC group, dietary supplementation with 0.10 % and 0.20 % of ε-polylysine improved growth performance, meat quality and intestinal morphology, evidenced by increased average daily gain, decreased feed-to-gain ratio, increased water holding capacity of breast muscle, and increased jejunal and ileal villus height in ε-polylysine-treated broilers (P < 0.05). In addition, 0.10 % and 0.20 % of ε-polylysine supplementation improved serum nitrogen metabolism, immune and antioxidant capacity to varying degrees. No significant diffrences in growth performance, meat quality, or intestinal morphology were observed among PC and ε-polylysine-supplemented groups (P > 0.05). Interestingly, compared with the PC group, dietary 0.10 % of ε-polylysine positively altered the microbiota composition of broilers, evidenced by the increased the relative abundance of beneficial bacteria (e.g., Faecalibacterium and Phascolarctobacterium) and decreased the abundance of harmful bacteria (e.g., Lachnoclostridium and Peptococcus). In conclusion, diets supplemented with ε-polylysine have beneficial effects on growth performance, meat quality, and gut health of broilers via replenishing lysine or favorably altering immune and antioxidant capacity and gut microbiota. The recommended supplemental amount of ε-polylysine in lysine-deficient diets (L-lysine content in the starter and growing diet is 0.95 % and 0.80 % of the basal diet, respectively) is 0.10 %-0.20 %.

Protective effect of the branched short-chain fatty acid isobutyrate on intestinal damage in weaned piglets through intestinal microbiota remodeling

BACKGROUND

Postweaning intestinal damage in piglets is a challenging issue in the livestock industry. Short-chain fatty acids (SCFAs) are important metabolic products of the gut microbiota and are widely recognized for their role in maintaining normal colonic function and regulating the intestinal immune system. However, the effects of branched short-chain fatty acid (BSCFA) isobutyrate on intestinal health remain largely unknown. This study aims to explore the potential of isobutyrate for alleviating postweaning intestinal damage.

RESULTS

This study indicates that isobutyrate can alleviate diarrhea in weaned piglets, enhance their growth performance, and optimize the gut microbiota. This is mainly achieved through increasing the relative abundance of probiotic bacteria such as Lactobacillus, Megasphaera, and Prevotellaceae_UCG-003, while concurrently reducing the relative abundance of potentially harmful bacteria such as Clostridium_sensu_stricto-1 and Escherichia-Shigella. It promotes the production of SCFAs, including acetate, isobutyrate, and butyrate. Furthermore, it activates G-protein-coupled receptors (GPR43/109A), inhibits the TLR4/MyD88 signaling pathway, strengthens the intestinal barrier function, and regulates the expression of related cytokines.

CONCLUSION

In summary, exogenous isobutyrate can be considered a promising feed additive for improving the intestinal microbiota and regulating intestinal health in piglets. © 2024 Society of Chemical Industry.

Effects of isoquinoline alkaloids as an alternative to antibiotic on oxidative stress, inflammatory status, and cecal microbiome of broilers under high stocking density

This study investigated the effect of isoquinoline alkaloids as an alternative to bacitracin on growth performance, oxidative stress, inflammatory status, and ceca microbiome of broilers raised under high stocking density (HSD). A total of 1,500 one-day-old male Ross 308 chicks were randomly assigned to five treatment groups, with 10 replicate pens per group and 30 birds per pen, for 37 days. The treatments included normal stocking density (NSD, 10 birds/m²), HSD (15 birds/m²), HSD with 50 ppm Bacitracin (BCT50), HSD with 80 ppm isoquinoline alkaloids (IQA80), and HSD with 100 ppm isoquinoline alkaloids (IQA100). From days 11 to 24, HSD birds had lower feed efficiency (P < 0.05) compared to those in other treatments. The heterophil-to-lymphocyte ratio and malondialdehyde levels were lower in NSD and IQA80 birds compared to HSD and BCT50 birds (P < 0.05). HSD birds had higher IL-6 and a lower villus height and villus height-to-crypt depth ratio compared to birds in other groups (P < 0.05). Serum TNF-α was lower in NSD and IQA80 birds compared to those in the HSD group. Alpha diversity was not affected by the treatments; however, beta diversity was lower in HSD birds compared to other treatments. HSD birds showed reduced microbial diversity, with a higher prevalence of Enterococcaceae and Peptostreptococcaceae. NSD enhanced the abundance of Lactobacillaceae, Clostridiaceae, and Rikenellaceae. BCT50 increased and decreased the abundance of Enterococcaceae and Rikenellaceae respectively. IQA80 and IQA100 increased the abundance of Lachnospiraceae, Leuconostocaceae, and Coriobacteriaceae. HSD altered metabolic pathways related to carbohydrate and lipid metabolism, and amino acid biosynthesis. BCT50 modulated microbial functions, particularly those related to cell wall synthesis, while isoquinoline alkaloids upregulated pathways involved in energy production, secondary metabolite biosynthesis, and antioxidant production. Both Bacitracin and isoquinoline alkaloids were effective in mitigating the negative effects of HSD on immunity, gut health and microbiota in broilers. Given the concerns about antimicrobial resistance, isoquinoline alkaloids are a potent alternative to bacitracin, with IQA80 being particularly recommended.

Effects of hesperidin, thymol, rosmarinic acid and their combined effect on growth performance, intestinal barrier function and cecal microbiota in broilers

This study aims to investigate the effects of hesperidin (Hes), thymol (Thy), rosmarinic acid (RA) and their combined effect on broiler growth performance, intestinal barrier function, and cecal microbiota. A total of 240 newly hatched Arbor Acres broiler chicks were randomly divided into 5 treatments with 6 replicates of 8 chickens. The birds were fed a basal diet (Con group), a basal diet supplemented with 40 mg/kg Hes (Hes group), a basal diet supplemented with 40 mg/kg Thy (Thy group), a basal diet supplemented with 20 mg/kg RA (RA group), or a basal diet supplemented with 40 mg/kg Hes + 40 mg/kg Thy + 20 mg/kg RA (HTR group) for 42 d. The results indicated that dietary Hes and HTR supplementation enhanced average daily gain, final body weight, and eviscerated yield of broilers compared with the Con group (P < 0.05). Notably, the HTR treatment showed a decrease in abdominal fat yield and ratio of feed to weight gain (P < 0.05). HTR treatment increased ileal villus height, villus height/crypt depth, and number of goblet cells, decreased the crypt depth (P < 0.05), up-regulated the mRNA expression of tight junction proteins (ZO-1, Claudin-1, Occludin) and MUC2 (P < 0.05). Hes, Thy, RA, HTR treatment decreased the concentrations of pro-inflammatory factors (IL-8, IFN-γ and TNF-α), and down-regulated the mRNA expression of TLR4/MyD88/NF-κB (P < 0.05). Importantly, the supplementation of HTR increased the relative abundance of beneficial bacteria (Parabacteroides, Lachnosiraceae NK4A136 and Turicbacter) and significantly decreased the relative abundance of opportunistic pathogenic bacteria such as Colidextribacter (P < 0.05). Additionally, the concentrations of propionate and butyrate in the cecum were elevated in the HTR group (P < 0.05). These findings indicate that the diet supplemented with HTR improved the growth performance and intestinal barrier function in broilers by modulating the cecal microbiota and its metabolites.

Poultry Nutrition: Achievement, Challenge, and Strategy

Poultry, a vital economic animal, provide a high-quality protein source for human nutrition. Over the past decade, the poultry industry has witnessed substantial achievements in breeding, precision feeding, and welfare farming. However, there are still many challenges restricting the sustainable development of the poultry industry. First, overly focused breeding strategies on production performance have been shown to induce metabolic diseases in poultry. Second, a lack of robust methods for assessing the nutritional requirements poses a challenge to the practical implementation of precision feeding. Third, antibiotic alternatives and feed safety management remain pressing concerns within the poultry industry. Lastly, environmental pollution and inadequate welfare management in farming have a negative effect on poultry health. Despite numerous proposed strategies and innovative approaches, each faces its own set of strengths and limitations. In this review, we aim to provide a comprehensive understanding of the poultry industry over the past decade, by examining its achievements, challenges, and strategies, to guide its future direction.

Effects of Housing Systems on Production Performance, Egg Quality, Tonic Immobility and Feather Score in Laying Hens

BACKGROUND

This study was designed to investigate the effects of different housing systems on production performance, egg quality and welfare in laying hens.

METHODS

One hundred and twenty 42-week-old "Atak S" laying hens, purchased from a manufacturing company, were randomly assigned to 4 housing systems: conventional cages, furnished cages, deep-litter system and free-range. Each system housed 30 hens, which were kept in these systems for 6 weeks. Parameters regarding production performance, egg quality, plumage condition scores and tonic immobility were assessed at the end of the housing period.

RESULTS

Egg production and egg mass were lower in cage-free rearing systems than in caged systems. Mean egg weight in free-range hens, and albumen height and Haugh unit in deep-litter hens, were lower than in other housing systems. Eggshell weight in hens housed in furnished cages was greater than in free-range hens, while eggshell strength was better compared to that of hens in conventional cages. The housing system did not impact fearfulness; however, the deep-litter housing increased the sensitivity to touch or capture. Whole body and regional plumage condition scores of free-range hens elicited more favourable results than those kept in conventional cages. Because the plumage condition indicates welfare, the results proved the superiority of free-range over conventional rearing regarding welfare.

CONCLUSIONS

Concerning the parameters, such as egg production, animal welfare and fear level, overall data revealed the pros and cons of all housing systems investigated. We consider that this study's findings might contribute to the researchers and breeders seeking alternative housing for laying hens.

Broiler flocks in production systems with slower-growing breeds and reduced stocking density receive fewer antibiotic treatments and have lower mortality

In the Netherlands, the number of broiler production systems with higher welfare standards, using slower-growing broilers and decreased stocking densities, has increased over the last decade. This study aimed to investigate the effect of this change on antibiotic treatments, mortality, and footpad lesions. Data from national monitoring databases from 2013 to 2021 were used, resulting in 113,380 included flocks from 917 farms. Flocks were divided into conventional (CONV), medium-growing (MED), and slow-growing (SLOW), based on breed and slaughter age (median age: CONV 42 d; MED 50 d; SLOW 56 d). Generalized mixed-effect models were created to compare antibiotic treatments in and after the first week, total on-farm mortality, and footpad lesion scores between these 3 production systems. Year, quarter, flock size, thinning, number of houses, and regional density of poultry farms were included as fixed effects. Random effects were farm and veterinary practice in all models, with an additional random slaughterhouse effect to describe footpad lesions. Probability of treatment in the first week of age in CONV flocks overall years (7.2%, 95% CI [5.9, 8.7]) was higher than in MED (2.0%, 95% CI [1.6, 2.5]) and SLOW flocks (1.3%, 95% CI [1.0, 1.7]). Treatment probability after the first week was similarly higher in CONV flocks (14.7%, 95% CI [12.1, 17.6]) than in MED (3.2%, 95% CI [2.5, 4.0]) and SLOW flocks (2.2%, 95% CI [1.7, 2.9]). CONV flocks had a higher mean mortality (3.2%, 95% CI [3.0, 3.4]) than MED (2.0%, 95% CI [1.9, 2.1]) and SLOW flocks (1.9%, 95% CI [1.8, 2.0]). Regarding footpad lesions, CONV flocks had the highest mean scores (range 0-200) over all years, whereas SLOW flocks had the lowest scores (CONV: 46.1, 95% CI [42.1, 50.6]; MED: 21.3, 95% CI [18.9, 24.0]; SLOW: 13.2, 95% CI [11.5, 15.1]). This analysis of data from flocks over a 9-yr period indicates that switching from conventional to alternative production systems with higher welfare standards could positively affect broiler health and antibiotic use.

Dietary advanced chelate technology-based 7-mineral supplement improves growth performance and intestinal health indicators during a mixed Eimeria challenge in broiler chickens

The health and productivity of broilers may be improved by optimizing the availability and levels of trace minerals (TM) in their feed, especially in the presence of parasites. This study investigated the effects of replacing inorganic TM (ITM) with an advanced chelate technology-based 7 TM (ACTM) on performance, hematology, lesion score, oocyst shedding, gut morphology, and tight junction structure in broilers challenged with mixed Eimeria species. There were 480 1-day-old broiler chickens divided into 5 groups: uninfected negative control and recommended levels of ITM (NC); infected positive control and recommended levels of ITM (PC); or PC supplemented with salinomycin (SAL); PC diet with 50 % ACTM instead of ITM (ACTM50); or PC diet with 100 % ACTM instead of ITM (ACTM100). All groups, except NC, were orally challenged with mixed Eimeria spp. oocysts on day 14. Each group had 6 replicate cages, with 16 birds per replicate. The results showed that the NC, SAL, and ACTM100 groups had higher (P < 0.05) body weight, average daily gain (ADG), and European production efficiency index (EPEI), as well as a lower (P < 0.05) feed conversion, mortality rate, and heterophile to lymphocyte ratio compared to the PC group, with the NC group having the highest ADG and EPEI throughout the experiment. The SAL and ACTM100 groups had lower (P < 0.05) intestinal lesion scores and oocyst numbers compared to the PC group, although all coccidiosis-challenged groups had higher oocyst shedding compared to the NC group. On day 24, the challenged birds in the SAL and ACTM100 groups had higher (P < 0.05) villus height and surface area in the duodenum and ileum, as well as a higher (P < 0.05) villus height to crypt depth ratio in the jejunum. The expression levels of jejunal CLDN1 and ZO-1 were also higher (P < 0.05) in the ACTM100 and SAL groups compared to the PC and ACTM50 groups at 24 days of age. In conclusion, while using ACTM in broiler diets at 50 % of the commercial recommended levels maintained performance and physiological responses, complete replacement with ACTM improved growth performance and intestinal health characteristics, similar to salinomycin under Eimeria challenge conditions.

Effect of Dietary Benzoic Acid Supplementation on Growth Performance, Rumen Fermentation, and Rumen Microbiota in Weaned Holstein Dairy Calves

Supplementation with benzoic acid (BA) in animal feed can reduce feeds' acid-binding capacity, inhibit pathogenic bacterial growth, enhance nutrient digestion, and increase intestinal enzyme activities. This study aimed to investigate the effects of different doses of BA on the growth performance, rumen fermentation, and rumen microbiota of weaned Holstein dairy calves. Thirty-two Holstein calves at 60 days of age were randomly assigned into four groups (n = 8): a control group (fed with a basal diet without BA supplementation; CON group) and groups that were supplemented with 0.25% (LBA group), 0.50% (MBA group), and 0.75% (HBA group) BA to the basal diet (dry matter basis), respectively. The experiment lasted for 42 days, starting at 60 days of age and ending at 102 days of age, with weaning occurring at 67 days of age. Supplementation with BA linearly increased the average daily gain of the weaned dairy calves, which was significantly higher in the LBA, MBA, and HBA groups than that in the CON group. The average daily feed intake was quadratically increased with increasing BA supplementation, peaking in the MBA group. Supplementation with BA linearly decreased the feed-to-gain (F/G) ratio, but did not affect rumen fermentation parameters, except for the molar proportion of butyrate and iso-butyrate, which were linearly increased with the dose of BA supplementation. Compared with the CON group, the molar proportions of iso-butyrate in the LBA, MBA, and HBA groups and that of butyrate in the HBA group were significantly higher than those in the CON group. Supplementation with BA had no significant effect on the alpha and beta diversity of the rumen microbiota, but significantly increased the relative abundances of beneficial bacteria, such as Bifidobacterium, and reduced those of the harmful bacteria, such as unclassified_o__Gastranaerophilales and Oscillospiraceae_UCG-002, in the rumen. Functional prediction analysis using the MetaCyc database revealed significant variations in the pathways associated with glycolysis across groups, including the GLYCOLYSIS-TCA-GLYOX-BYPASS, GLYCOL-GLYOXDEG-PWY, and P105-PWY pathways. In conclusion, BA supplementation improved the composition and function of rumen microbiota, elevated the production of butyrate and iso-butyrate, and increased the growth performance of weaned Holstein dairy calves.

Insights into the evaluation, influential factors and improvement strategies for poultry meat quality: a review

Poultry meat, an essential source of animal protein, requires stringent safety and quality measures to address public health concerns and growing international attention. This review examines both direct and indirect factors that compromise poultry meat quality in intensive farming systems. It highlights the integration of rapid and micro-testing with traditional methods to assess meat safety. The paper advocates for adopting probiotics, prebiotics, and plant extracts to improve poultry meat quality.

Effect of dietary aspirin eugenol ester on the growth performance, antioxidant capacity, intestinal inflammation, and cecal microbiota of broilers under high stocking density

This study was designed to examine the impact of aspirin eugenol ester (AEE) on the growth performance, serum antioxidant capacity, jejunal barrier function, and cecal microbiota of broilers raised under stressful high density (HD) stocking conditions compared with normal density broilers (ND). A total of 432 one-day-old AA+ male broilers were randomly divided into 4 groups: normal density (ND, 14 broilers /m2), high density (HD, 22 broilers /m2), ND + AEE, and HD + AEE. The results of the study revealed a significant decrease in the growth performance of broiler chickens as a result of HD stress (P < 0.05). The total antioxidant capacity (T-AOC) in serum demonstrated a significant decrease (P < 0.05) at both 28 and 35 d. Conversely, the serum level of malondialdehyde (MDA) exhibited a significant increase (P < 0.05). Dietary supplementation of AEE resulted in a significant elevation (P < 0.05) of serum GSH-PX, SOD and T-AOC activity at both 28 and 35 d. Moreover, exposure to HD stress resulted in a considerable reduction in the height of intestinal villi and mRNA expression of tight junction proteins in the jejunum, along with, a significant elevation in the mRNA expression of inflammatory cytokines (P < 0.05). However, the administration of AEE reversed the adverse effects of HD-induced stress on villus height and suppressed the mRNA expression of the pro-inflammatory genes, COX-2 and mPGES-1. Additionally, the exposure to HD stress resulted in a substantial reduction in the α-diversity of cecal microbiota and disruption in the equilibrium of intestinal microbial composition, with a notable decrease in the relative abundance of Bacteroides and Faecalibacterium (P < 0.05). In contrast, the addition of AEE to the feed resulted in a notable increase in the relative abundance of Phascolarctobacterium and enhanced microbial diversity (P < 0.05). The inclusion of AEE in the diet has been demonstrated to enhance intestinal integrity and growth performance of broilers by effectively mitigating disruptions in gut microbiota induced by HD stress.

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.

Dietary supplementation with Neolamarckia cadamba leaf extract improves broiler meat quality by enhancing antioxidant capacity and regulating metabolites

This study was to evaluate the effect of supplementing the diet of broilers with Neolamarckia cadamba leaf extract (NCLE) on meat quality by evaluating antioxidant parameters and the expression of genes in the p38 mitogen-activated protein kinase/nuclear factor-erythroid 2-related factor 2/antioxidant responsive element (p38 MAPK/Nrf2/ARE) signaling pathway, coupled with LC-MS-based metabolomic analysis. A total of 480 one-day-old male broilers were randomly allocated to four treatment groups-a control (CON) group, which was fed a basal diet, and three NCLE treatment groups, which were fed the basal diet supplemented with 100, 200, or 400 mg/kg NCLE (N1, N2, and N3 groups, respectively) for 42 d. Compared with the CON group, meat quality was improved in the N2 and N3 groups, as evidenced by the higher pH45min (P < 0.05) and lower shear force (P < 0.05) in breast muscle (BM) and lower drip loss at 48 h (P < 0.05) in leg muscle (LM). Moreover, BM antioxidant capacity was significantly enhanced in the N3 group, characterized by an increase in the total antioxidant capacity (T-AOC), the concentrations of glutathione peroxidase (GSH-Px) and catalase (CAT), and the relative mRNA expression of p38 MAPK, extracellular-signal regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), Nrf2, CAT, and GSH-Px (P < 0.05). Similarly, LM in the N3 group displayed higher T-AOC, increased GSH-Px and CAT concentrations, reduced malonaldehyde contents (P < 0.05), and upregulation of the relative mRNA levels of JNK, Nrf2, heme oxygenase, CAT, and superoxide dismutase (SOD) (P < 0.05). Metabolomics analysis revealed that D-arabinono-1,4-lactone and lyso-PAF C-16-d4 were negatively correlated with shear force and cooking loss (P < 0.05) and displayed increased abundance in BM of the N3 group. L-Serine levels were upregulated while D-fructose 1,6-diphosphate contents were downregulated in the three NCLE groups. Finally, the differential metabolites in both BM and LM were involved in amino acid metabolism pathways. Our results indicated that NCLE supplementation improved meat quality by enhancing antioxidant enzyme activities, promoting the expression of genes in the p38 MAPK/Nrf2/ARE signaling pathway, and regulating amino acid metabolism. The optimal NCLE concentration was found to be 400 mg/kg.

Investigation of Potential Gut Health Biomarkers in Broiler Chicks Challenged by Campylobacter jejuni and Submitted to a Continuous Water Disinfection Program

The exploration of novel biomarkers to assess poultry health is of paramount importance, not only to enhance our understanding of the pathogenicity of zoonotic agents but also to evaluate the efficacy of novel treatments as alternatives to antibiotics. The present study aimed to investigate potential gut health biomarkers in broiler chicks challenged by Campylobacter jejuni and subjected to a continuous water disinfection program. A total of 144 one-day-old hatched broiler chicks were randomly allocated to four treatment groups with four replicates each, according to the following experimental design: Group A received untreated drinking water; Group B received drinking water treated with 0.01-0.05% v/v Cid 2000™ (hydrogen peroxide, acetic acid and paracetic acid); Group C was challenged by C. jejuni and received untreated drinking water; and Group D was challenged by C. jejuni and received drinking water treated with 0.01-0.05% v/v Cid 2000™. The use of Cid 2000™ started on day 1 and was applied in intervals until the end of the experiment at 36 days, while the C. jejuni challenge was applied on day 18. Potential biomarkers were investigated in serum, feces, intestinal tissue, intestinal content, and liver samples of broilers. Statistical analysis revealed significant increases (p < 0.001) in serum cortisol levels in C. jejuni-challenged broilers. Serum fluorescein isothiocyanate dextran (FITC-d) increased significantly (p = 0.004) in broilers challenged by C. jejuni and treated with drinking water disinfectant, while fecal ovotransferrin concentration also increased significantly (p < 0.001) in broilers that received the drinking water disinfectant alone. The gene expression levels of occludin (p = 0.003) and mucin-2 (p < 0.001) were significantly upregulated in broilers challenged by C. jejuni, while mucin-2 significantly increased in birds that were challenged and received the drinking water disinfectant (p < 0.001). TLR-4 expression levels were significantly (p = 0.013) decreased in both groups that received the drinking water disinfectant, compared to the negative control group. Finally, the C. jejuni challenge significantly increased (p = 0.032) the crypt depth and decreased (p = 0.021) the villus height-to-crypt-depth ratio in the ileum of birds, while the tested disinfectant product increased (p = 0.033) the villus height in the jejunum of birds. Furthermore, the counts of C. jejuni in the ceca of birds (p = 0.01), as well as its translocation rate to the liver of broilers (p = 0.001), were significantly reduced by the addition of the water disinfectant. This research contributes to novel insights into the intricate interplay of water disinfection and/or C. jejuni challenge with potential intestinal biomarkers. In addition, it emphasizes the need for continued research to unveil the underlying mechanisms, expands our understanding of broiler responses to these challenges and identifies breakpoints for further investigations.

Cold stress initiates catecholaminergic and serotonergic responses in the chicken gut that are associated with functional shifts in the microbiome

Climate change is one of the most significant challenges facing the sustainability of global poultry production. Stress resulting from extreme temperature swings, including cold snaps, is a major concern for food production birds. Despite being well-documented in mammals, the effect of environmental stress on enteric neurophysiology and concomitant impact on host-microbiome interactions remains poorly understood in birds. As early life stressors may imprint long-term adaptive changes in the host, the present study sought to determine whether cold temperature stress, a prominent form of early life stress in chickens, elicits changes in enteric stress-related neurochemical concentrations that coincide with compositional and functional changes in the microbiome that persist into the later life of the bird. Chicks were, or were not, subjected to cold ambient temperature stress during the first week post-hatch and then remained at normal temperature for the remainder of the study. 16S rRNA gene and shallow shotgun metagenomic analyses demonstrated taxonomic and functional divergence between the cecal microbiomes of control and cold stressed chickens that persisted for weeks following cessation of the stressor. Enteric concentrations of serotonin, norepinephrine, and other monoamine neurochemicals were elevated (P < 0.05) in both cecal tissue and luminal content of cold stressed chickens. Significant (P < 0.05) associations were identified between cecal neurochemical concentrations and microbial taxa, suggesting host enteric neurochemical responses to environmental stress may shape the cecal microbiome. These findings demonstrate for the first time that early life exposure to environmental temperature stress can change the developmental trajectory of both the chicken cecal microbiome and host neuroendocrine enteric physiology. As many neurochemicals serve as interkingdom signaling molecules, the relationships identified here could be exploited to control the impact of climate change-driven stress on avian enteric host-microbe interactions.

Trehalose Supplementation Effects on Growth, Intestinal Morphology, Gut Bacteria, and Footpad Dermatitis of Broiler Chickens Reared at High Density

This study aimed to measure the effects of trehalose (Tre) supplementation on the growth, intestinal morphology, gut bacteria, and footpad dermatitis (FPD) of broiler chickens reared at different stocking densities (SD). Four hundred newly hatched Ross 308 male chicks were randomly allocated to four groups of eight, following a 2 × 2 factorial arrangement in a randomized complete block design using two SDs (normal, 11; high, 14 birds/m2) and two diets: basal with and without 0.5% Tre. Tre supplementation was provided during the starter/grower phase, but not the finisher phase. Data were analyzed using a two-way analysis of variance. We observed no significant effects of SD or Tre, individually or combined, on body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) during the starter/grower period. However, high SD decreased both BWG (P < 0.001) and FI (P < 0.05), and increased FCR (P < 0.001), during the finisher period. Whereas Tre reduced FCR (P < 0.05) as a main effect, no combined effect was observed on FCR. Over the total period, high SD negatively affected BWG and FCR (P < 0.001), and Tre significantly reduced FCR, with its effect unaffected by SD. No significant effects of SD or Tre were observed on jejunal morphology. The ileal abundance of Clostridium perfringens (P > 0.05) was not affected by high SD but was significantly reduced by Tre. Neither high SD nor Tre altered Lactobacillus spp. counts; however, high SD increased FPD lesion scores, whereas Tre had no effect. The study showed that Tre supplementation during the starter/grower period improved FCR during the finisher period, possibly by decreasing the abundance of C. perfringens in broiler chickens.

Effect of an organic acid blend as an antibiotic alternative on growth performance, antioxidant capacity, intestinal barrier function, and fecal microbiota in weaned piglets

This study was conducted to evaluate the effects of dietary organic acid blend on growth performance, antioxidant capacity, intestinal barrier function, and fecal microbiota in weaned piglets compared with antibiotic growth promoters (AGPs). A total of 90 weaned crossbred barrows (24 ± 1 d of age) with an initial body weight of 7.40 kg were allocated into three experimental treatments. Each treatment consisted of six replicate pens, with five piglets housed in each pen. The dietary treatments included the basal diet (NC), the basal diet supplemented with antibiotics (PC), and the basal diet supplemented with organic acid blend (OA). On day 42, one piglet per pen was randomly selected for plasma and small intestinal sample collection. The results showed that dietary AGP significantly improved growth performance and reduced diarrhea incidence compared to the NC group (P < 0.05). Dietary OA tended to increase body weight on day 42 (P = 0.07) and average daily gain from days 0 to 42 (P = 0.06) and reduce diarrhea incidence (P = 0.05). Dietary OA significantly increased plasma catalase (CAT) activity and decreased the plasma concentration of malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin (IL)-8, and IL-6, which were accompanied by upregulated the relative mRNA abundance of superoxide dismutase 1 (SOD1), glutathione peroxidase 1 (GPX1), and nuclear factor erythroid 2-related factor 2 (NRF2) in comparison to that in the NC group (P < 0.05). Moreover, pigs fed the OA diet significantly increased the ratio of villus height to crypt depth and upregulated the relative expression of zonula occludens-1 (ZO-1) and Claudin1 gene in the jejunum compared to the NC group (P < 0.05). Interestingly, dietary AGP or OA did not affect the fecal microbiota structure or volatile fatty acid content (P > 0.05). In conclusion, our results suggested that dietary OA supplementation could improve growth performance and antioxidant capacity and protect the intestinal barrier of weaned piglets, therefore, it has the potential to be considered as an alternative to AGP in the pig industry.

Effects of Enteromorpha prolifera polysaccharides on growth performance, intestinal barrier function and cecal microbiota in yellow-feathered broilers under heat stress

BACKGROUND

Global warming leading to heat stress (HS) is becoming a major challenge for broiler production. This study aimed to explore the protective effects of seaweed (Enteromorpha prolifera) polysaccharides (EPS) on the intestinal barrier function, microbial ecology, and performance of broilers under HS. A total of 144 yellow-feathered broilers (male, 56 days old) with 682.59 ± 7.38 g were randomly assigned to 3 groups: 1) TN (thermal neutral zone, 23.6 ± 1.8 °C), 2) HS (heat stress, 33.2 ± 1.5 °C for 10 h/d), and 3) HSE (HS + 0.1% EPS). Each group contained 6 replicates with 8 broilers per replicate. The study was conducted for 4 weeks; feed intake and body weights were measured at the end of weeks 2 and 4. At the end of the feeding trial, small intestine samples were collected for histomorphology, antioxidant, secretory immunoglobulin A (sIgA) content, apoptosis, gene and protein expression analysis; cecal contents were also collected for microbiota analysis based on 16S rDNA sequencing.

RESULTS

Dietary EPS promoted the average daily gain (ADG) of broilers during 3-4 weeks of HS (P < 0.05). At the end of HS on broilers, the activity of total superoxide dismutase (T-SOD), glutathione S-transferase (GST), and the content of sIgA in jejunum were improved by EPS supplementation (P < 0.05). Besides, dietary EPS reduced the epithelial cell apoptosis of jejunum and ileum in heat-stressed broilers (P < 0.05). Addition of EPS in HS group broilers' diet upregulated the relative mRNA expression of Occludin, ZO-1, γ-GCLc and IL-10 of the jejunum (P < 0.05), whereas downregulated the relative mRNA expression of NF-κB p65, TNF-α and IL-1β of the jejunum (P < 0.05). Dietary EPS increased the protein expression of Occludin and ZO-1, whereas it reduced the protein expression of NF-κB p65 and MLCK (P < 0.01) and tended to decrease the protein expression of TNF-α (P = 0.094) in heat-stressed broilers. Furthermore, the proportions of Bacteroides and Oscillospira among the three groups were positively associated with jejunal apoptosis and pro-inflammatory cytokine expression (P < 0.05) and negatively correlated with jejunal Occludin level (P < 0.05). However, the proportions of Lactobacillus, Barnesiella, Subdoligranulum, Megasphaera, Collinsella, and Blautia among the three groups were positively related to ADG (P < 0.05).

CONCLUSIONS

EPS can be used as a feed additive in yellow-feathered broilers. It effectively improves growth performance and alleviates HS-induced intestinal injury by relieving inflammatory damage and improving the tight junction proteins expression. These beneficial effects may be related to inhibiting NF-κB/MLCK signaling pathway activation and regulation of cecal microbiota.

Supplementing Genistein for Breeder Hens Alters the Growth Performance and Intestinal Health of Offspring

Recent research revealed that dietary genistein supplementation for breeder hens can improve the immune function of offspring chicks. However, it remains unknown whether this maternal effect could improve the intestinal health of offspring. This study was conducted to explore the mechanism involved in the maternal effect of genistein on the intestinal mucosa and microbial homeostasis of chicken offspring. A total of 120 Qiling breeder hens were fed a basal diet, a 20 mg/kg genistein-supplemented diet, or a 40 mg/kg genistein-supplemented diet for 4 weeks before collecting their eggs. After hatching, 180 male offspring (60 chickens from each group) were randomly selected and divided into three groups: (1) the offspring of hens fed a basal diet (CON); (2) the offspring of hens fed a low-dose genistein-supplemented diet (LGE); (3) the offspring of hens fed a high-dose genistein-supplemented diet (HGE). At 17 d, 72 male offspring (48 chickens from CON and 24 chickens from LGE) were divided into three groups: (1) the offspring of hens fed a basal diet (CON); (2) the CON group challenged with LPS (LPS); (3) the LGE group challenged with LPS (LPS + LGE). The results showed that maternal genistein supplementation increased the birth weight and serum level of total protein (TP), followed by improved intestinal villus morphology. Continuously, the maternal effect on the body weight of chicks lasted until 21 d. Additionally, it was observed that maternal genistein supplementation exhibited protective effects against LPS-induced morphological damage and intestinal mucosal barrier dysfunction by upregulating the expression of tight junction proteins, specifically ZO-1, Claudin1, E-cadherin, and Occludin, at 21 d. Using 16S rRNA gene sequencing, we demonstrated that maternal supplementation of genistein has the potential to facilitate the maturation of newly hatched chicken offspring by enhancing the abundance of Escherichia coli. Additionally, maternal genistein supplementation can effectively reduce the abundance of Gammaproteobacteria, thus mitigating the risk of bacterial diversity impairment of LPS. In light of these findings, maternal genistein supplementation holds promise as a potential strategy for ameliorating intestinal mucosal damage and modulating the microbiome in chicken offspring.

Effects of dietary chlorogenic acid on intestinal barrier function and the inflammatory response in broilers during lipopolysaccharide-induced immune stress

Immune stress exerts detrimental effects on growth performance and intestinal barrier function during intensive animal production with ensuing serious economic consequences. Chlorogenic acid (CGA) is used widely as a feed additive to improve the growth performance and intestinal health of poultry. However, the effects of dietary CGA supplementation on amelioration of the intestinal barrier impairment caused by immune stress in broilers are unknown. This study investigated the effects of CGA on growth performance, intestinal barrier function, and the inflammatory response in lipopolysaccharide (LPS) mediated immune-stressed broilers. Three hundred and twelve 1-day-old male Arbor Acres broilers were divided randomly into 4 groups with 6 replicates of thirteen broilers. The treatments included: i) saline group: broilers injected with saline and fed with basal diet; ii) LPS group: broilers injected with LPS and fed with basal diet; iii) CGA group: broilers injected with saline and feed supplemented with CGA; and iv) LPS+CGA group: broilers injected with LPS and feed supplemented with CGA. Animals in the LPS and LPS+CGA groups were injected intraperitoneally with an LPS solution prepared with saline from 14 d of age for 7 consecutive days, whereas broilers in the other groups were injected only with saline. LPS induced a decrease in feed intake of broilers during the stress period, but CGA effectively alleviated this decrease. Moreover, CGA inhibited the reduction of villus height and improved the ratio of villus height to crypt depth in the duodenum of broilers 24 and 72 h after LPS injection. In addition, dietary CGA supplementation significantly restored the expression of cation-selective and channel-forming Claudin2 protein 2 h after LPS injection in the ileum. LPS enhanced the expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the small intestine, but this enhancement was blocked by CGA supplementation. The expression of interleukin-10 (IL-10) increased with LPS injection and CGA promoted the production of IL-10. CGA addition downregulated the expression of intestinal interleukin-6 (IL-6) of broilers under normal rearing conditions. However, CGA supplementation upregulated the expression of IL-6 of broilers 72 h after LPS injection. The data demonstrate that dietary supplementation with CGA alleviates intestinal barrier damage and intestinal inflammation induced by LPS injection during immune stress thereby improving growth performance of broilers.

Dietary Supplementation with Chlorogenic Acid Enhances Antioxidant Capacity, Which Promotes Growth, Jejunum Barrier Function, and Cecum Microbiota in Broilers under High Stocking Density Stress

Chlorogenic acids (CGA) are widely used as feed additives for their ability to improve growth performance and intestinal health in poultry. However, whether dietary CGAs could reverse the impaired intestinal condition caused by high stocking density (HD) in broiler chickens is unknown. We determined the effect of dietary CGA on growth, serum antioxidant levels, jejunum barrier function, and the microbial community in the cecum of broilers raised under normal (ND) or HD conditions. HD stress significantly decreased growth and body weight, which was restored by CGA. The HD group showed increased serum malondialdehyde, an oxidative byproduct, and decreased SOD and GSH-Px activity. CGA reduced malondialdehyde and restored antioxidant enzyme activity. HD stress also significantly decreased jejunal villus length and increased crypt depth. Compared with ND, the expression of tight-junction genes was significantly decreased in the HD group, but this decrease was reversed by CGA. HD also significantly upregulated TNF-α. Compared with ND, the cecal microbiota in the HD group showed lower alpha diversity with increases in the harmful bacteria Turicibacter and Shigella. This change was altered in the HD + CGA group, with enrichment of Blautia, Akkermansia, and other beneficial bacteria. These results demonstrated that HD stress decreased serum antioxidant capacity, inhibited the development of jejunal villi, and downregulated expression of tight-junction genes, which increased intestinal permeability during the rapid growth period (21 to 35 days). Dietary CGA enhanced antioxidant capacity, improved intestinal integrity, and enhanced beneficial gut bacteria in chickens raised under HD conditions.