Holistic view of intestinal health in poultry

Dietary Oregano Oil Supplementation Improved Egg Quality by Altering Cecal Microbiota Function in Laying Hens

Improving egg quality is one of the main objectives of the poultry industry. The objective of this study was to investigate the effects of dietary oregano oil supplementation with different concentrations on the egg quality, intestinal morphology and cecal microbiome of late-phase laying hens. A total of 300 55-week-old Snowy white laying hens were randomly divided into five groups and fed a basal diet (control) or basal diets supplemented with oregano oil at 25, 50, 75 and 100 mg/kg (O25, O50, O75 and O100) over a 100-day period. Compared with the control group, eggshell thickness and eggshell weight were increased significantly in eggs when oregano oil was added (p < 0.05). The highest content of polyunsaturated fatty acids (PUFAs) and C18:2n6c was observed in yolks with 25 mg/kg supplement among 5 groups (p < 0.05). The highest average content of riboflavin in egg yolk and thiamine in egg white was observed in the O25 group (p < 0.05). When the supplemental levels of oregano oil were 25 mg/kg and 50 mg/kg, the selenium and phosphorus content in the egg was significantly increased (p < 0.05). The ratio of villus height to crypt depth (V/C) and villus height of the small intestine was significantly increased compared with the chickens fed the basal diet (p < 0.05). Compared with the control group, the abundance of Megamonas was increased in the O50 group (p < 0.05). The unclassified_o__Bacteroidales in the O25 group were significantly higher than those in the other four groups (p < 0.05). These differential microorganisms were significantly correlated with egg quality characteristics. Dietary supplementation of oregano oil can significantly improve egg quality via gut microbiota alteration in laying hens.

The gut microbiota and its metabolite butyrate shape metabolism and antiviral immunity along the gut-lung axis in the chicken

The gut microbiota exerts profound influence on poultry immunity and metabolism through mechanisms that yet need to be elucidated. Here we used conventional and germ-free chickens to explore the influence of the gut microbiota on transcriptomic and metabolic signatures along the gut-lung axis in poultry. Our results demonstrated a differential regulation of certain metabolites and genes associated with innate immunity and metabolism in peripheral tissues of germ-free birds. Furthermore, we evidenced the gut microbiota's capacity to regulate mucosal immunity in the chicken lung during avian influenza virus infection. Finally, by fine-analysing the antiviral pathways triggered by the short-chain fatty acid (SCFA) butyrate in chicken respiratory epithelial cells, we found that it regulates interferon-stimulated genes (ISGs), notably OASL, via the transcription factor Sp1. These findings emphasize the pivotal role of the gut microbiota and its metabolites in shaping homeostasis and immunity in poultry, offering crucial insights into the mechanisms governing the communication between the gut and lungs in birds.

Plasma Biochemistry, Intestinal Health, and Transcriptome Analysis Reveal Why Laying Hens Produce Translucent Eggs

Producing translucent eggs has been found to reduce the quality and safety of the eggs, as well as the demand from consumers. However, the intestinal function and the molecular mechanism for the production of translucent eggs remain uncertain. A total of 120 eggs from 276-day-old Jining Bairi were divided into two groups based on eggshell translucence: the translucent egg group (group T) and the normal group (group C). Group T exhibited thicker eggshells and a lower egg yolk color. Subsequently, we divided the chickens into translucent and normal groups based on their egg quality. We then assessed the plasma biochemical index, intestinal morphology and structure, enzyme activity, and antioxidant capacity of the hens producing translucent eggs compared to those producing normal eggs. The results showed that the ratio of duodenal villus length to crypt depth, succinate dehydrogenase (SDH) activity, chymotrypsin, total ATPase (T-ATPase), alkaline phosphatase (AKP), and glutathione peroxidase (GSH-Px) activities were decreased in the hens produced translucent eggs (p < 0.05), but malondialdehyde (MDA) content was increased (p < 0.05); jejunal lipase activity, Na+K+-ATPase activity, total antioxidant capacity (T-AOC), and GSH-Px activities were decreased (p < 0.05) in group T; ileal amylase and Ca2+Mg2+-ATPase activities were also decreased (p < 0.05) in group T. In addition, we identified a total of 471 differentially expressed genes (DEGs) in duodenal tissue, with 327 up-regulated genes and 144 down-regulated genes (|log2FC| ≥ 1 and p < 0.05). Enrichment analysis showed that the up-regulated genes, such as GSTT1, GSTO2, and GSTA3, were mostly enriched in metabolism of xenobiotics by cytochrome P450, drug metabolism-cytochrome P450, and oxidative phosphorylation pathways. The results of our study indicate that plasma lipid metabolism disorder, decreased intestinal antioxidant capacity, and altered intestinal metabolism capabilities may influence the formation of translucent eggs.

Effect of β-Alanine Metabolite on Gut Integrity and Immunity in Commercial Broiler Chickens Infected with Eimeria maxima

(1) Background: In a metabolomics analysis conducted to investigate the mechanisms behind the growth-promoting effects of probiotics in broilers, β-alanine was found to be significantly elevated. This led to the hypothesis that β-alanine could also contribute to growth-promoting effects in infected broilers. (2) Methods: An in vitro culture system was developed to assess β-alanine's impact on proinflammatory cytokine response in chicken macrophage cells, gut integrity in chicken intestinal epithelial cells, and muscle differentiation in quail muscle cells and primary chicken embryonic muscle cells. In vivo animal feeding studies were then conducted to investigate the effects of dietary β-alanine on various disease parameters in Eimeria maxima-infected broiler chickens. (3) Results: In vitro, β-alanine treatment significantly decreased the gene expression of cytokines in chicken macrophage cells and increased occuldin expression in chicken intestinal epithelial cells. Dietary β-alanine increased the body weight of chickens following Eimeria maxima infection in the H-ALA group. Dietary β-alanine also suppressed cytokines and increased JAM-2 and occludin expression in the H-ALA group compared to the infected group without β-alanine supplementation. (4) Conclusions: These results strongly support the positive effects of dietary β-alanine on intestinal immune responses and gut barrier function in broiler chickens infected with Eimeria maxima.

Effects of bamboo leaf flavonoids on growth performance, antioxidants, immune function, intestinal morphology, and cecal microbiota in broilers

BACKGROUND

Bamboo leaf flavonoids (BLF) are the main bioactive ingredients in bamboo leaves. They have antioxidant, anti-inflammatory, antibacterial, and other effects. In this study, the effects of dietary BLF on growth performance, immune response, antioxidant capacity, and intestinal microbiota of broilers were investigated. A total of 288 broilers were divided into three groups with eight replicates and 12 birds in each replicate. Broilers were fed a basic diet or the basic diet supplemented with 1000 or 2000 mg kg-1 BLF for 56 days.

RESULTS

The results showed that supplementation of BLF increased body weight (BW) and average daily weight gain (ADG), and reduced average daily feed intake (ADFI) (P < 0.05). The serum immunoglobulin A (IgA), immunoglobulin M (IgM), and interleukin 10 (IL-10) content of broilers in the BLF1000 group was increased and the interleukin 1β (IL-1β) and tumor necrosis factor-α (TNF-α) content was decreased (P < 0.05). The levels of IgM and IL-10 in jejunum mucosa were found to be enhanced by BLF (P < 0.05). The BLF1000 group exhibited a significant reduction in the concentration of TNF-α (P < 0.05). Serum and jejunum mucosa total antioxidant capacity (T-AOC) levels in the BLF1000 group were increased (P < 0.05). The serum catalase (CAT) and glutathione peroxidase (GSH-Px) effects of the BLF1000 group and serum CAT effects of BLF2000 group were increased (P < 0.05). The CON group demonstrated a lower relative abundance of Christensenellaceae_R-7_group and Oscillibacter than the BLF group (P < 0.05).

CONCLUSION

Dietary BLF inclusion enhanced the growth performance, immune, and antioxidant functions, improved the intestinal morphology, and ameliorated the intestinal microflora structure in broiler. Adding 1000 mg kg-1 BLF to the broiler diet can be considered as an effective growth promoter. © 2024 Society of Chemical Industry.

Effects of gossypol acetate on growth, serum biochemical parameters, and intestinal health of goslings

Free gossypol (FG), the primary antinutritional component in cottonseed meal, can adversely affect the growth and health of poultry. Although younger geese are particularly sensitive to FG, the precise effects of FG on geese remain elusive. This study aimed to investigate the effects of gossypol acetate (GA), a form of FG, on the growth, serum biochemical parameters, and intestinal health of goslings. Seventy-two healthy male goslings, aged 7-day-old with similar body weight (BW), were randomly divided into 3 groups: a control group and 2 GA-treated groups (GA25 and GA50), which were orally administered GA (25 and 50 mg/kg BW) daily for 14 d. The results showed that oral administration of GA significantly suppressed BW, altered serum parameters, and impaired intestinal health in a dose- and time-dependent manner. Specifically, GA adversely affected intestinal morphology, induced oxidative stress, and inflammation, diminished immune function, and increased intestinal permeability and apoptosis of intestinal cells, consequently impairing nutrient absorption and utilization of goslings. Overall, these data indicate that GA adversely affects the growth, serum parameters, and intestinal health of goslings, providing valuable information further to understand the toxic effects of gossypol on goslings.

Dietary supplementation with a silicate clay mineral (palygorskite) alleviates inflammatory responses and intestinal barrier damage in broiler chickens challenged with Escherichia coli

This experiment aimed to explore the protective effects of dietary palygorskite (Pal) supplementation on inflammatory responses and intestinal barrier function of broiler chickens challenged with Escherichia coli (E. coli). A 2 × 2 factorial arrangement was designed to assess the effects of Pal administration (0 or 5 g/kg of feed) and E. coli challenge (E. coli or bacterial culture medium) on broilers in a 21-d feeding trial. Birds were randomly assigned into one of the 4 groups, and each group had 8 replicates with ten birds each. The challenged chickens were orally gavaged with E. coli suspended in Luria-Bertani broth on 14 d of age, while unchallenged birds were administrated with an equivalent amount of culture medium. The sampling was performed at 21 d of age. Compared with the normal birds, an oral E. coli challenge reduced final body weight, and decreased feed intake, weight gain, and feed efficiency during the challenge period (P < 0.05). E. coli challenge promoted colonization of E. coli in cecal content and their translocation to internal organs (heart, liver, and spleen) (P < 0.05). E. coli infection also increased levels of pro-inflammatory cytokines in jejunum and ileum possibly through activating the toll-like receptor-4-mediated signaling pathway (P < 0.05). Moreover, E. coli administration increased intestinal mucosal permeability (higher serum D-lactate level and diamine oxidase activity, and lower intestinal mucosal disaccharidase activities), altered intestinal morphology, and downregulated the gene expression of intestinal tight junction proteins (P < 0.05). In contrast, Pal supplementation enhanced growth performance, inhibited colonization of E. coli, reduced intestinal inflammation, decreased intestinal permeability, restored intestinal morphology, and normalized the expression of genes responsible for inflammatory processes and maintenance of intestinal mucosal barrier (P < 0.05), and most of these beneficial effects resulting from Pal administration were independent of bacterial challenge. The results indicated dietary Pal incorporation was effective in improving growth performance and alleviating inflammation and intestinal mucosal barrier damage in broilers challenged with E. coli.

Protective effects of chlorogenic acid on the intestinal barrier of broiler chickens: an immunological stress model study

This study was conducted to investigate the protective effects of chlorogenic acid (CGA) on inflammatory responses and intestinal health of lipopolysaccharide (LPS)-challenged broilers. One hundred and forty-four 1-day-old male broiler chicks were divided into 3 groups with 6 replicates of 8 birds each. The groups were as follows: 1) Control group: birds fed a basal diet; 2) LPS group: LPS-challenged birds fed a basal diet; 3) CGA group: LPS-challenged birds fed a CGA-supplemented diet. The LPS was intraperitoneally administered at a dose of 1 mg/kg of body weight. CGA increased the weight gain and feed intake of LPS-challenged birds by 37.05% and 24.29%, respectively (P < 0.05). CGA also alleviated LPS-induced inflammation, as evidenced by lower levels of pro-inflammatory cytokines in the serum and jejunum (tumor necrosis factor-α, interferon-γ, interleukin-1β, and interleukin-6), and the decreased myeloperoxidase activity in the jejunum (P < 0.05). These effects were accompanied by a decrease in the mRNA abundance of toll-like receptor 4 and myeloid differentiation factor 88 and an inhibition of nuclear factor kappa-B translocation in the jejunum (P < 0.05). CGA reduced circulating diamine oxidase activity and levels of D-lactate and endotoxin, and positively regulated the expression of jejunal claudin-3 and zonula occludens-1 in LPS-challenged broilers (P < 0.05). Compared to the LPS group, CGA reduced the apoptotic rate of epithelial cells and cytochrome c concentration in the jejunum, and normalized the expression of genes responsible for proliferation and apoptosis in jejunal epithelial cells, including cysteine aspartate-specific protease-9, B cell lymphoma-2, and proliferating cell nuclear antigen (P < 0.05). Furthermore, CGA normalized the altered phosphorylation of protein kinase B and glycogen synthase kinase-3β, as well as the translocation of nuclear β-catenin in the jejunum of LPS-challenged broilers (P < 0.05). These results suggested that CGA supplementation improved growth performance, alleviated inflammation, and helped maintain intestinal integrity and barrier function in LPS-challenged broilers, possibly through the regulation of the toll-like receptor 4/nuclear factor kappa-B and protein kinase B/Wnt/β-catenin pathways.

Effect of different synbiotic administration methods on growth, carcass characteristics, ileum histomorphometry, and blood biochemistry of Cobb-500 broilers

Background and Aim

To combat enteric infections and antibiotic resistance in the poultry industry, researchers seek alternatives such as probiotics, prebiotics, and synbiotics as growth promoters. Synbiotics support probiotic growth through the supply of essential nutrients. The study's objectives were to assess the most effective delivery methods for synbiotics and evaluate their growth, histomorphometric, and hematological impacts on Cobb-500 broilers.

Materials and Methods

Two studies, independently conducted, employed a completely randomized design. One hundred and eighty viable eggs in the first trial were assigned to three groups: Control (T1), sterile water (T2), and synbiotic in sterile water (T3). On the 21st day of hatching, hatchability, day-old body weights, and ileum samples for histomorphometric analysis were recorded. In the second trial, out of 500 viable eggs, 200 eggs were fed in ovo with synbiotics (PoultryStar® sol, Biomin Singapore Pte Ltd, Singapore) on 17.5 days and 300 were set aside without in ovo injection. The treatments were control (T1), in water synbiotic (T2), in ovo synbiotic (T3), combination of in ovo synbiotic and synbiotic in feed (T4), and synbiotic in feed only (T5). On 21 and 42 days, blood, ileum, and visceral organ samples were collected for laboratory analysis. Data on weight gain, daily feed intake, and water consumption were recorded for 42 days.

Results

The initial experiment's results revealed a decrease in hatchability, slight weight increase, and significant intestinal morphological changes with the use of an in ovo synbiotic. Applying synbiotic through various methods in the second trial yielded better growth results, lower blood cholesterol, and significantly longer (p < 0.05) villi on 21 days.

Conclusion

Using the in ovo method to administer synbiotics lowered hatchability. Use of synbiotics with any method or in combination enhances growth, ileum structure, dressing yield, feed efficiency, and cholesterol levels in blood. Synbiotics enhance gut health and overall performance in broilers when used through diverse approaches.

Feeding strategy and prebiotic supplementation: Effects on immune responses and gut health in the early life stage of broiler chickens

This study aimed to investigate the effects of early or late feeding strategies and prebiotic, on immune responses and gut health during the early life stage of broiler chickens. A total of 240 day-old male broiler chicks were used in a 2 × 3 factorial arrangement of treatments that comprised 2 feeding strategies (early or late) and 3 levels of prebiotic (0, recommended dosage or three times the recommended dosage) in a completely randomized design with 4 pen replicates and 10 broilers per each. Compared to broiler chickens that had early access to feed, delayed access to feed resulted in an increased population of Escherichia coli and a decreased population of Lactobacillus spp. and Bifidobacterium spp. in the ileum (P < 0.05). Additionally, delayed access to feed led to a decrease in villus height, crypt depth, villus height: villus width ratio, goblet cell density, and mucin 2 gene expression in the ileum (P < 0.05). The supplementation of prebiotics in both the late and early feeding strategy groups resulted in increased villus height, crypt depth, goblet cell density, mucin 2 gene expression, and antibodies against Infectious Bursal Disease (IBD). Additionally, it led to an improvement in the foot web thickness index (P < 0.05). Furthermore, it resulted in a significant decrease in the population of Escherichia coli, while the populations of Lactobacillus spp. and Bifidobacterium spp. in the ileum were significantly increased (P < 0.05). Therefore, this study suggests that incorporating prebiotics in the starter diet can effectively enhance immune responses and promote gut health, regardless of the feeding strategy (early or late). In conclusion, this study demonstrates the potential benefits of incorporating prebiotics into poultry diets to alleviate the detrimental effects of delayed access to feed and improve gut health during the early life stage of broiler chickens.

Chlorogenic acid ameliorates intestinal inflammation by inhibiting NF-κB and endoplasmic reticulum stress in lipopolysaccharide-challenged broilers

Intestinal inflammation is a primary contributor to poor growth performance during poultry production. Chlorogenic acid (CGA) is a natural phenolic acid that exhibits superior anti-inflammatory activity and improved intestinal health. To investigate the protective effects and molecular mechanisms of CGA during intestinal inflammation in lipopolysaccharide (LPS)-challenged broilers, we randomly divided 288 one-day-old male Cobb broilers into 4 groups: a control group fed a basal diet (CON group), a basal diet + LPS group (LPS group), and 2 basal diet groups fed 500 or 750 mg/kg CGA + LPS (CGA_500 or CGA_750 groups). Broilers were injected with LPS or saline at 15, 17, 19, and 21 d old. Chlorogenic acid supplementation improved the growth performance of LPS-challenged broilers by increasing average daily gain (ADG) and reducing feed/gain (F/G) ratios (P < 0.05). CGA also improved intestinal barrier function in LPS-challenged boilers by enhancing jejunum morphology and integrity, decreasing intestinal permeability, and increasing occludin 3, zonula occludens-1, and mucin 2 expression (P < 0.05). CGA supplementation also improved systemic and jejunum antioxidant capacity by significantly enhancing glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activities (P < 0.05), and reducing malonaldehyde (MDA) and protein carbonyl (PCO) levels (P < 0.05). Chlorogenic acid supplementation reduced systemic and jejunum pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, and IL-12) and increased anti-inflammatory cytokines (IL-10) in LPS-challenged broilers (P < 0.05) by inhibiting the toll like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway (P < 0.05). In addition, the protective effects of CGA toward intestinal inflammation and apoptosis appeared to be correlated with inhibited endoplasmic reticulum (ER) stress (P < 0.05). In summary, CGA supplementation improved intestinal morphology and integrity by inhibiting TLR4/NF-κB and ER stress pathways, which potentially reduced oxidative stress and inflammation, and ultimately improved the growth performance of LPS-challenged broilers.

The impact of bacillus pumilus TS2 isolated from yaks on growth performance, gut microbial community, antioxidant activity, and cytokines related to immunity and inflammation in broilers

Intensive poultry farming faces challenges like gut inflammation in the absence of antibiotics, resulting in reduced productivity, heightened susceptibility to enteric diseases, and other complications. Alternative strategies are needed to manage inflammation and maintain sustainable poultry production. Yaks living in high-altitude hypoxic environments have specialized gut microbes. However, yak probiotics remain largely uncharacterized. We previously isolated a strain of Bacillus pumilus (named TS2) from yaks and demonstrated its potential as a probiotic in vitro. Therefore, in this study, we evaluated the in vivo growth-promoting, antioxidant, immune, and anti-inflammatory effects of Bacillus pumilus isolated from yaks in broilers. We demonstrated the safety of TS2 isolated from yaks in broilers. Furthermore, we found that TS2 increased the average daily weight gain (ADWG) and reduced the feed conversion ratio (FCR). Supplementation with TS2 also improved the mucosal morphology, the ratio of villi to crypt cells, and enzyme activity. High-throughput sequencing showed that the abundance of Lactobacillus was higher in the TS2 treated broilers. Importantly, the serum level of malondialdehyde (MDA) was reduced and the levels of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity were increased in the low-dose TS2 group, while the inflammatory factors interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were downregulated compared with the control group. We demonstrated that TS2 supplementation can increase the overall growth performance and ameliorate the blood parameters related to inflammation and immunity in broilers.

Prophybiotics for in-ovo stimulation; validation of effects on gut health and production of broiler chickens

Probiotics and phytobiotics have demonstrated effective improvement of gut health in broiler chickens when individually administered in-ovo. However, their combined use in-ovo, has not been studied to date. We coined the term "prophybiotic" (probiotic + phytobiotic) for such a combination. The current study therefore, aimed to elucidate the effects of combined use of a selected probiotic and a phytobiotic in-ovo, on broiler gut health and production parameters, as opposed to use of probiotics alone. ROSS 308 hatching eggs were injected with either Leuconostoc mesenteroides (probiotic: PB) or L. mesenteroides with garlic aqueous extract (prophyiotic: PPB) on the 12th day of incubation. Relative abundances of bacteria in feces and cecal content (qPCR), immune related gene expression in cecal mucosa (qPCR) and histomorphology of cecal tissue (PAS staining) were analyzed along with production parameters (hatch quality, body weight, feed efficiency and slaughter and meat quality). PPB treatment increased the abundance of faecalibacteria and bifidobacteria in feces (d 7) and Akkermansia sp. in cecal content. Moreover, it decreased Escherichia coli abundance in both feces (d 34) and cecal content. PB treatment only increased the faecalibacteria in feces (d 7) and Akkermansia sp. in the cecal content. Moreover, PPB treatment resulted in up-regulation of immune related genes (Avian beta defensing 1, Free fatty acid receptor 2 and Mucin 6) and increased the crypt depth in ceca whereas PB treatment demonstrated a higher crypt depth and a tendency to increase Mucin 6 gene expression. Both treatments did not impair the production parameters studied. In conclusion, our results suggest that in-ovo PPB treatment may have enhanced potential in boosting the immune system without compromising broiler production and efficiency, as compared to the use of probiotic alone. Our study, highlights the potential of carefully selected PPB combinations for better results in improving gut health of broiler chickens.

Chitosan oligosaccharide improves intestinal function by promoting intestinal development, alleviating intestinal inflammatory response, and enhancing antioxidant capacity in broilers aged d 1 to 14

This study was conducted to investigate the effects of chitosan oligosaccharide (COS) supplementation on intestinal development and functions, inflammatory response, antioxidant capacity and the related signaling pathways in broilers aged d 1 to 14. A total of 240 one-day old male Arbor Acres broilers (40.47 ± 0.30 g) were randomly allotted to 4 groups, and each group consisted of 6 replicate pens with 10 broilers per replicate. Broilers fed a basal diet supplementation with COS at 0 (CON group), 200 (COS200 group), 400 (COS400 group), and 800 mg/kg (COS800 group) for 14 d, respectively. Broilers in the COS supplementation groups had no significant effects on growth performance. Compared to the CON group, dietary COS supplementation increased (P < 0.05) the relative weight of duodenum, jejunal lipase activity, duodenal and ileal villus surface area, and lower (P < 0.05) ileal amylase and alkaline phosphatase activity, and crypt depth. The expression level of duodenal glucose transporter 1 (GLUT1), Na+-glucose cotransporter 1 (SGLT1), peptide transporter 1 (PepT1), occludin, zonula occludens-1 (ZO-1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and interleukin-10 (IL-10), jejunal SGLT1, PepT1, occludin, tumor necrosis factor-α (TNF-α), and ileal SGLT1, PepT1, and fatty acid binding protein 1 (FABP1) was upregulated by COS. However, the expression level of duodenal FABP1 and TNF-α, jejunal GLUT1, ZO-1, TLR4, MyD88, nuclear factor kappa-B p65 (NF-κB p65), and IL-1β, and ileal GLUT1, NF-κB p65, and IL-1β was downregulated by COS. Furthermore, dietary COS supplementation increased duodenal catalase (CAT), glutathione peroxidase (GSH-Px), and total superoxide dismutase (T-SOD) activity, jejunal CAT and T-SOD activity, upregulated the expression level of duodenal nuclear factor-erythroid 2-related factor 2 (Nrf2), CAT, glutathione peroxidase 1 (GPX1), and copper and zinc superoxide dismutase (Cu/Zn SOD), jejunal CAT, and ileal Nrf2, CAT, and GPX1. These results suggested that COS could promote intestinal development and functions in broilers aged d 1 to 14, which might be mediated by alleviating intestinal inflammatory response and enhancing antioxidant capacity.

The dual sugar test (lactulose plus mannitol) is an unreliable indicator of feed withdrawal-associated changes in intestinal permeability in broiler chickens

Despite its importance in poultry research, there is lack of standardized and practical techniques to measure intestinal permeability in a noninvasive manner. Therefore, this research sought to standardize a procedure using lactulose (Lac) and mannitol (Man) to measure intestinal barrier function in broilers. Twenty-one-day-old male and female Ross 308 birds were orally gavaged (either 2 mL/kg BW or fixed 3 mL per bird) with a solution containing 5 to 25 g Lac and 1 to 5 g Man dissolved in pure water to reach 100 mL of final solution. Feed withdrawal (FW; 2-24-h duration) prior to dosing with Lac and Man (LacMan) was mainly used to induce graded intestinal permeability. Blood samples were collected at 60-, 90-, or 120-min after LacMan dosing using serum or plasma (K2EDTA and/or Na-Heparin) blood tubes. Lac and Man concentrations were quantified by HPLC. Plasma samples collected 90-min after LacMan dosing elicited the least variable response (22.4% vs. 22.8% or 23.4% CV when compared with 60- and 120-min sampling time-points, respectively), and both markers were detectable after administering a solution containing the lowest concentration of Lac and Man. However, analytical problems arose when using Na-Heparin anticoagulant as high glucose levels interfered with Lac quantification. Upon improving the chromatographic technique, it became evident that a 24-h FW increased (P < 0.01) Lac concentrations. In the last trial, a more severe glucose interference was observed, resulting in no Lac detection within an entire treatment group. Twelve hours of FW increased (P < 0.01) Man concentration in the plasma of birds receiving the solution containing 3 g Man, but had no effect on the birds receiving the solution containing 5 g Man. A 24-h FW did not affect the Man concentrations in birds receiving the solution containing either 3 or 5 g Man. With inconsistency of Lac detection throughout our trials, it was concluded that the combination of Lac and Man is an unreliable marker to predict intestinal barrier function in broilers.

Evaluation of Natural Antimicrobial Substances Blend as a Replacement for Antibiotic Growth Promoters in Broiler Chickens: Enhancing Growth and Managing Intestinal Bacterial Diseases

In recent years, commercial use of antibiotic growth promoter (AGP) has restrictions due to drug resistance against intestinal pathogenic bacteria: Escherichia coli, Salmonella, and Clostridium perfringens. Currently there is no single non-antibiotic treatment approach that is effective against intestinal illnesses in broiler chicken. Hence, present study aimed to analyze efficacy of blend of natural antimicrobial substances (probiotics, prebiotics, organic acids, and essential oils blend named as AGPR) as replacers of AGPs (BMD and CTC) for promoting growth and controlling bacterial diseases in aforementioned three microbes challenged broiler chickens. Effects of treatments (5) and microbes (3) on growth and health performances in experimental birds were analyzed using two factorial ANOVA. Health performance like pathogen loads, morbidity and mortality was considerably reduced by AGPR. Similarly small intestine villi morphometry, nutrition utilization, serum immune response, and carcass yield, was improved significantly by AGPR equivalent to AGPs. Further, growth performance like body weight gain, feed efficiency was also improved by AGPR compared to control but, non-significantly. Among three microbes, E. coli infections had higher morbidity and mortality rates. It was concluded that AGPR blend could be used to improve growth and control the intestinal bacterial infections in broiler chickens as an alternative for AGPs.

Xylanase and beta-glucanase improve performance parameters and footpad dermatitis and modulate intestinal microbiota in broilers under an Eimeria challenge

Coccidiosis is an enteric disease of poultry worldwide that compromises gut health and growth performance. The current research investigated the effects of 2 doses of a multienzyme preparation on broilers' performance, gut health, and footpad dermatitis (FPD) under an Eimeria challenge. A total of 512 mixed-sex day-old chicks (Cobb 500) were randomly allocated to 4 treatments of 8 replicates. Treatments were: 1) nonchallenged control (NC); 2) NC + Eimeria challenge (CC); 3) CC + recommended level of xylanase and glucanase (XG, 100 g/t feed [on top]); 4) CC + double XG (2XG, 200 g/t feed). Eimeria spp. vaccine strains were gavaged on d 9 to induce coccidiosis in chickens. Performance parameters were evaluated during starter, grower, and finisher phases, and 4 birds per pen were euthanized on d 16 for sampling, FPD was scored on d 35, and litter moisture was analyzed on d 17 and 35. The data were analyzed using 1-way ANOVA with Tukey's test to separate means, and Kruskal-Wallis test was used for non-normally distributed parameters. The results showed that the Eimeria challenge was successful based on reduced weight gain and feed intake during grower phase, and higher FITC-d concentration, lesion score (female), and oocyst counts (d 14) in CC group compared to N.C. group, while XG and 2XG increased (P < 0.001) weight gain and improved FCR compared to CC and NC groups during finisher phase. The addition of X.G. and 2XG decreased litter moisture (P = 0.003) and FPD (P < 0.001) in challenged broilers compared to the N.C. group (d 35). Supplementing XG and 2XG reestablished the population of Lactobacillus in the cecum of challenged birds to an intermediate level between the NC and CC groups (P > 0.05). The inclusion of XG tended to increase the expression of Junctional adhesion molecule 2 (JAM2), which was not different from CC and NC groups (P > 0.05). In conclusion, the combination of xylanase and glucanase (Natugrain TS) improved the performance and modulated jejunal microbiota of broilers under mild Eimeria challenge.

Diet of Broilers with Essential Oil from Citrus sinensis and Xylopia aromatica Fruits

This study aimed to evaluate the effects of essential oils from the fruits of Citrus sinensis and Xylopia aromatica, included in broiler feed, on blood parameters, the biometrics of digestive organs, bone analyses, and the biochemical profiles of the viscera, as well as the histomorphometry of the small intestine. In this study, 180 one-day-old male chicks of the Cobb 500 strain were fed a corn and soybean meal over three treatments and six replications, and the experimental design was completely randomized. The data were subjected to an analysis of variance and a Tukey test at a 5% significance level. The effect of the experimental diets on performance, blood parameters, biometrics of the digestive organs, bone analysis, and biochemical profiles of the viscera, as well as the histomorphometry of the small intestine, were evaluated. The compounds identified in the essential oil of X. aromatica were sylvestrene, α-pinene, and β-pinene, while in C. sinensis they were limonene and myrcene. The essential oils of C. sinensis and X. aromatica had no significant effect on performance at 14 days. The effects of the presence of the essential oils of C. sinensis and X. aromatica on the response were beneficial: there were reductions in liver lipids, cholesterol, and triglycerides, and in the depths of the crypts in the jejunum of chickens. So, the essential oils from the fruits of C. sinensis and X. aromatica can be used in broiler chickens to improve the lipid profiles of birds without affecting their performance.

Health effects of feed dilution and roughage in Ross 308 broiler breeder cockerels

To ensure reproductivity and prevent obesity, broiler breeder's growth rate is controlled by quantitative feed restriction. However, feed restriction is associated with chronic hunger, frustration, and abnormal behaviors, thus representing a welfare problem. Feed diluted with insoluble fiber is an alternative, allowing larger amounts of feed and more gut filling, increasing satiety without increasing the caloric intake. Previous research on feed dilution has focused on pullets not cockerels. In addition, the health effects of diluted feed are less explored. The aim of this study was to investigate the effects of feed dilution and roughage on health indicators in broiler breeder cockerels, 5 to 10 wk of age (WOA), a very feed restricted period. In total, 200 Ross 308 broiler breeder cockerels were housed in 12 pens (6 pens/treatment), 16 to 17 birds per pen. The treatments were standard feed (Control) and feed diluted with (20%) insoluble oat hulls and 150 g of roughage (lucerne/alfalfa) daily per pen (D + R). The D + R birds received 20% more feed per day. Body weight, pecking injuries, footpad dermatitis (FPD), and litter quality were recorded weekly between 5 and 9 WOA. At 10 WOA all birds were euthanized and subjected to postmortem assessment. D + R birds tended to weigh more than controls (P = 0.055), but diet did not affect flock uniformity (P = 0.57). The weekly assessment showed no effect of treatment on foot pad lesion scores (P = 0.31). However, an effect on FPD was observed postmortem (P = 0.04), where Control had slightly better footpad condition compared to the D + R group. Litter had to be completely changed in 2 control pens during the trial, due to quality deterioration. There was no effect of treatment on the weight of specific organs, the length of the gut, the intestinal mucosa, nor on the incidence of wounds on the head (P = 0.15). Overall, these results indicate that feed dilution and roughage have neither adverse nor beneficial health effects on Ross 308 broiler breeder cockerels.

Interactive Effect of Dietary Heat-Killed Lactobacillus Plantarum L-137 and Berberine Supplementation on Intestinal Mucosa and Microbiota of Juvenile Black Sea Bream (Acanthopagrus Schlegelii)

To compare the synergistic impact of dietary heat-killed Lactobacillus plantarum and berberine supplementation on intestinal health of juvenile black sea bream, the test fish (5.67 ± 0.05 g) were fed three diets: a basal control diet designated as Con; basal diet supplemented with 400 mg/kg L. plantarum, labelled LP; and basal diet supplemented with 400 mg/kg L. plantarum + 50 mg/k berberine, labelled LPBB. After 56 days of feeding, the control fish had significantly lower intestinal villus height (VH), villus surface area (VSA), and muscularis mucosae (MS) thickness than the rest of the groups (P < 0.05). The LPBB fish had significantly higher VH than the control fish, and wider MS and VSA than the rest of the groups (P < 0.05). Occludin was significantly upregulated in the LPBB fish, and heat shock protein 90 was upregulated in the control fish (P < 0.05). The abundance of Proteobacteria family was significantly higher in the intestinal microbiome of the control and LP fish, the LPBB fish had higher abundance of Cyanobacteria and Spirochaetes, and the LP group had higher Bacteroidetes abundance (P < 0.05). Potentially beneficial Delftia and Brevinema were the significantly abundant genera in the LP and LPBB fish, respectively; potentially pathogenic Elizabethkingia was abundant in the LP fish; and the control fish had higher abundance of potentially pathogenic Burkholderia-Caballeronia-Paraburkholderia (P < 0.05). According to these results, there is possible synergy between L. plantarum and berberine as dietary supplements in fostering healthy intestine for black sea bream than L. plantarum alone.

Holistic Strategies to Control Salmonella Infantis: An Emerging Challenge in the European Broiler Sector

Salmonella spp. has been globally recognized as one of the leading causes of acute human bacterial gastroenteritis resulting from the consumption of animal-derived products. Salmonella Enteritidis, S. Typhimurium, and its monophasic variant are the main serovars responsible for human disease. However, a serovar known as S. Infantis has emerged as the fourth most prevalent serovar associated with human disease. A total of 95% of isolated S. Infantis serovars originate from broilers and their derived products. This serovar is strongly associated with an elevated antimicrobial (AMR) and multidrug resistance, a resistance to disinfectants, an increased tolerance to environmental mercury, a heightened virulence, and an enhanced ability to form biofilms and attach to host cells. Furthermore, this serovar harbors genes that confer resistance to colistin, a last-resort antibiotic in human medicine, and it has the potential to acquire additional transferable AMR against other critically important antimicrobials, posing a new and significant challenge to global public health. This review provides an overview of the current status of the S. Infantis serovar in the poultry sector, focusing on its key virulence factors, including its virulence genes, antimicrobial resistance, and biofilm formation. Additionally, novel holistic strategies for controlling S. Infantis along the entire food chain are presented in this review.

Effects of Short- and Medium-Chain Fatty Acids on Production, Meat Quality, and Microbial Attributes-A Review

The non-therapeutic use of antimicrobials in poultry production contributes to the spread of drug-resistant pathogens in both birds and humans. Antibiotics are known to enhance feed efficiency and promote the growth and weight gain of poultry. New regulatory requirements and consumer preferences have led to a reduced use of antibiotics in poultry production and to the discovery of natural alternatives to antibiotic growth promoters. This interest is not only focused on the direct removal or inhibition of causative microorganisms but also on the prevention of diseases caused by enteric pathogens using a range of feed additives. A group of promising feed additives is composed of short- and medium-chain fatty acids (SCFAs and MCFAs) and their derivatives. MCFAs possess antibacterial, anticoccidial, and antiviral effects. In addition, it has been proven that these acids act in synergy if they are used together with organic acids, essential oils, or probiotics. These fatty acids also benefit intestinal health integrity and homeostasis in broilers. Other effects have been documented as well, such as an increase in intestinal angiogenesis and the gene expression of tight junctions. The aim of this review is to provide an overview of SCFAs and MCFAs as alternatives to antibiotic growth promoters and to summarize the current findings in the literature to show their possible benefits on production, meat quality, and gut health in poultry.

Effect of fermented heat-treated rice bran on performance and possible role of intestinal microbiota in laying hens

Rice bran is a high-quality and renewable livestock feed material rich in nutrients and bioactive substances. To investigate the effects of dietary supplementation with fermented heat-treated rice bran on the performance, apparent digestibility of nutrients, cecal microbiota and metabolites in laying hens, a total of 128 18-week-old Hy-Line brown layers were randomly assigned to four treatment groups: 2.5% HRB (basal diet contained 2.5% heat-treated rice bran), 5.0% HRB (5.0% heat-treated rice bran), 2.5% FHRB (2.5% fermented heat-treated rice bran), 5.0% FHRB (5.0% fermented heat-treated rice bran). Results showed that FHRB supplementation significantly increased the average daily feed intake (ADFI) during 25-28 weeks, and improved apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE) and crude fiber (CF) in laying hens. Moreover, feeding 5.0% of HRB and FHRB resulted higher egg production (EP) and average egg weight (AEW) during the feeding period, and decreased the feed conversion ratio (FCR) during 21 to 28 weeks. The alpha and beta diversity indices indicated that FHRB altered the cecal microbiota. In particular, dietary supplementation with FHRB significantly increased the relative abundances of Lachnospira and Clostridium. Compared with the 2.5% level of supplementation, supplementing 5.0% HRB and 5.0% FHRB increased the relative abundances of Firmicutes, Ruminococcus and Peptococcus, and lowered the relative abundance of Actinobacteria. Furthermore, dietary FHRB supplementation significantly increased the concentration of short-chain fatty acids in cecum and changed the overall metabolome. The results of correlation analysis showed a close interaction between cecal microbiota, metabolites and apparent digestibility of nutrients. Taken together, we revealed that FHRB supplementation can induce characteristic structural and metabolic changes in the cecal microbiome, which could potentially promote nutrient digestion and absorption, and improve the production performance of laying hens.

Administration of a Multi-Genus Synbiotic to Broilers: Effects on Gut Health, Microbial Composition and Performance

In recent years, the applicability of prebiotics, probiotics and their mixtures, defined as synbiotics, in poultry production has received considerable attention. Following the increasing regulation of antibiotic use, these nutraceuticals are seen as an alternative way to sustain production efficiency and resistance to pathogens and stressors by modulating birds' gut health. The aim of this study was to evaluate the benefits provided under field conditions by administering the multi-species synbiotic PoultryStar^® sol to broilers in drinking water. To this purpose, three Ross 308 broiler flocks, representing separate progenies of a breeder flock which was treated with the same synbiotic, were housed in separate farms, divided into treatment and control groups, and followed throughout the productive cycle. Synbiotic administration was shown to improve gut health even in absence of a challenge, with limited changes in terms of macroscopic intestinal lesions and more overt differences related to histopathological scores and villi length. Synbiotic-fed chickens performed consistently better in terms of body weight gain, feed conversion ratio and survivability. Lastly, the evaluation of the caecal microbiome through next-generation sequencing highlighted the effects of synbiotic supplementation on the composition of the bacterial population, the implications of which will, however, require further studies to be better comprehended.

Comparative efficacy of tannin-free grain sorghum varieties for the control of necrotic enteritis caused by Clostridium perfringens in broiler chickens

A 28-day battery cage study was conducted to test the efficacy of tannin-free grain sorghum varieties fed to Cobb 500 male broiler chickens (n = 512) and challenged with Eimeria maxima (EM) and Clostridium perfringens (CP). Birds were fed 1 of 8 treatments (corn, red/bronze, white/tan, or U.S. No. 2 sorghum) and were grouped by challenge method (challenged with EM/CP or unchallenged). On d 14, birds in the challenge group were orally inoculated with ∼5,000 oocysts of EM, and on d 19, 20, and 21, birds were given a broth culture of CP with ∼10⁸ CFU/mL once daily. On d 21, three birds were scored for the degree/presence of necrotic enteritis (NE) lesions. Birds and feed were group weighed (d 0, 14, 21, and 28) to calculate average feed intake (FI), body weight gain (BWG), and adjusted feed conversion ratio (AdjFCR). Intestinal integrity was assessed through histological analysis of intestinal tissues, and change in transcriptome was determined using mRNA-sequencing on intestinal mucosa. Relative concentrations of secondary metabolites in grain sorghum were determined by LC-MS/MS analysis. Data were analyzed as a 2-way ANOVA with factors of treatment, challenge and their interaction. Regardless of challenge from 14 to 21 d, birds on the corn, white/tan, and U.S. No. 2 treatments were more efficient than those fed red/bronze treatment (P = 0.0026). From 14 to 28 d, BWG was significantly higher for the white/tan treatment (P = 0.024) compared to the red/bronze treatment. At 21 d, a significant interaction was observed for lesion score (P = 0.0001) in which, challenged birds fed red/bronze and white/tan treatments had reduced intestinal lesions compared to U.S. No. 2 and corn treatments. No differences among treatments were observed in jejunum morphology, but differential expression analysis showed an upregulation in defense response to bacteria and biotic stress in the challenged red/bronze treatment compared to the challenged corn. This study demonstrated improved gut health and minimal impact on growth and efficiency of broilers fed select grain sorghum varieties when challenged with EM/CP.

Morphological Assessment and Biomarkers of Low-Grade, Chronic Intestinal Inflammation in Production Animals

Simple Summary

Production animals are continuously exposed to environmental and dietary factors that might induce a state of low-grade, chronic intestinal inflammation. This condition compromises the productive performance and well-fare of these animals, requiring studies to understand what causes it and to develop control strategies. An intestinal inflammatory process is generally associated with alterations in the structure and functionality of its wall, resulting in the release of cellular components into the blood and/or feces. These components can act as biomarkers, i.e., they are measured to identify and quantify an inflammatory process without requiring invasive methods. In this review we discuss the mechanisms of low-grade inflammation, its effects on animal production and sustainability, and the identification of biomarkers that could provide early diagnosis of this process and support studies of useful interventional strategies.

Abstract

The complex interaction between the intestinal mucosa, the gut microbiota, and the diet balances the host physiological homeostasis and is fundamental for the maximal genetic potential of production animals. However, factors such as chemical and physical characteristics of the diet and/or environmental stressors can continuously affect this balance, potentially inducing a state of chronic low-grade inflammation in the gut, where inflammatory parameters are present and demanding energy, but not in enough intensity to provoke clinical manifestations. It’s vital to expand the understanding of inflammation dynamics and of how they compromise the function activity and microscopic morphology of the intestinal mucosa. These morphometric alterations are associated with the release of structural and functional cellular components into the feces and the blood stream creating measurable biomarkers to track this condition. Moreover, the identification of novel, immunometabolic biomarkers can provide dynamic and predictors of low-grade chronic inflammation, but also provide indicators of successful nutritional or feed additive intervention strategies. The objective of this paper is to review the mechanisms of low-grade inflammation, its effects on animal production and sustainability, and the biomarkers that could provide early diagnosis of this process and support studies of useful interventional strategies.

An evaluation of the protective effects of chlorogenic acid on broiler chickens in a dextran sodium sulfate model: a preliminary investigation

This study was conducted to investigate the protective effects of chlorogenic acid (CGA) on broilers subjected to dextran sodium sulfate (DSS)-induced intestinal damage. One hundred and forty-four 1-day-old male Arbor Acres broiler chicks were allocated into one of 3 groups with 6 replicates of eight birds each for a 21-d trial. The treatments included: 1) Control group: normal birds fed a basal diet; 2) DSS group: DSS-treated birds fed a basal diet; and 3) CGA group: DSS-treated birds fed a CGA-supplemented control diet. An oral DSS administration via drinking water was performed from 15 to 21 d of age. Compared with the control group, DSS administration reduced 21-d body weight and weight gain from 15 to 21 d, but increased absolute weight of jejunum and absolute and relative weight of ileum (P < 0.05). DSS administration elevated circulating D-lactate concentration and diamine oxidase activity (P < 0.05), which were partially reversed when supplementing CGA (P < 0.05). The oral administration with DSS decreased villus height and villus height/crypt depth ratio, but increased crypt depth in jejunum and ileum (P < 0.05). Compared with the control group, DSS administration increased serum glutathione level and jejunal catalase activity and malonaldehyde accumulation, but decreased jejunal glutathione level (P < 0.05). In contrast, feeding a CGA-supplemented diet normalized serum glutathione and jejunal malonaldehyde levels, and increased jejunal glutathione concentration in DSS-administrated birds (P < 0.05). Additionally, CGA supplementation reduced ileal malonaldehyde accumulation in DSS-treated birds (P < 0.05). DSS challenge increased levels of serum interferon-γ and interleukin-6, jejunal interleukin-1β, tumor necrosis factor-α, and interleukin-6, and ileal interleukin-1β and interleukin-6 when compared with the control group (P < 0.05). The elevated serum interferon-γ and ileal interleukin-6 levels were normalized to control values when supplementing CGA (P < 0.05). The results suggested that CGA administration could partially prevent DSS-induced increased intestinal permeability, oxidative damage, and inflammation in broilers, although it did not improve their growth performance and intestinal morphology.

Potential Probiotics Role in Excluding Antibiotic Resistance

Background. Antibiotic supplementation in feed has been continued for the previous 60 years as therapeutic use. They can improve the growth performance and feed efficiency in the chicken flock. A favorable production scenario could favor intestinal microbiota interacting with antibiotic growth promoters and alter the gut bacterial composition. Antibiotic growth promoters did not show any beneficial effect on intestinal microbes. Scope and Approach. Suitable and direct influence of growth promoters are owed to antimicrobial activities that reduce the conflict between host and intestinal microbes. Unnecessary use of antibiotics leads to resistance in microbes, and moreover, the genes can relocate to microbes including Campylobacter and Salmonella, resulting in a great risk of food poisoning. Key Findings and Conclusions. This is a reason to find alternative dietary supplements that can facilitate production, growth performance, favorable pH, and modulate gut microbial function. Therefore, this review focus on different nutritional components and immune genes used in the poultry industry to replace antibiotics, their influence on the intestinal microbiota, and how to facilitate intestinal immunity to overcome antibiotic resistance in chicken.

Uncovering the core principles of the gut-lung axis to enhance innate immunity in the chicken

Research in mammals has evidenced that proper colonization of the gut by a complex commensal microbial community, the gut microbiota (GM), is critical for animal health and wellbeing. It greatly contributes to the control of infectious processes through competition in the microbial environment while supporting proper immune system development and modulating defence mechanisms at distant organ sites such as the lung: a concept named ‘gut-lung axis’. While recent studies point to a role of the GM in boosting immunity and pathogen resilience also in poultry, the mechanisms underlying this role are largely unknown. In spite of this knowledge gap, GM modulation approaches are today considered as one of the most promising strategies to improve animal health and welfare in commercial poultry production, while coping with the societal demand for responsible, sustainable and profitable farming systems. The majority of pathogens causing economically important infectious diseases in poultry are targeting the respiratory and/or gastrointestinal tract. Therefore, a better understanding of the role of the GM in the development and function of the mucosal immune system is crucial for implementing measures to promote animal robustness in commercial poultry production. The importance of early gut colonization in the chicken has been overlooked or neglected in industrial poultry production systems, where chicks are hampered from acquiring a complex GM from the hen. Here we discuss the concept of strengthening mucosal immunity in the chicken through GM modulation approaches favouring immune system development and functioning along the gut-lung axis, which could be put into practice through improved farming systems, early-life GM transfer, feeding strategies and pre-/probiotics. We also provide original data from experiments with germ-free and conventional chickens demonstrating that the gut-lung axis appears to be functional in chickens. These key principles of mucosal immunity are likely to be relevant for a variety of avian diseases and are thus of far-reaching importance for the poultry sector worldwide.

Impact of Dietary Supplementation with Sodium Butyrate Protected by Medium-Chain Fatty Acid Salts on Gut Health of Broiler Chickens

Nutritional strategies to improve gut health of broilers are under research. This study investigated the effect of dietary supplementation with sodium butyrate protected by sodium salts of medium-chain fatty acids as a feed additive on broiler gut health. The first experiment was conducted to evaluate the effect of supplementing at 0.5, 1, and 2 kg/t in broilers housed under optimal conditions. Supplementation at 0.5 and 1 kg/t maintained goblet cell counts at 10 days of age (p ≤ 0.05), and supplementation at 1 kg/t decreased intraepithelial lymphocyte counts compared to 2 kg/t at 39 days (p ≤ 0.10). Abdominal fat pad levels of lauric and myristic acids were gradually increased by supplement dose (p ≤ 0.05). In the second experiment, the feed additive at 1 kg/t was evaluated in coccidiosis-challenged broilers. Experimental treatments were as follows: non-challenged, control-challenged, and supplemented-challenged treatments. Coccidiosis negatively impact performance and modify histomorphometry and microbiota (p ≤ 0.05). The feed additive increased crypt depth at 7 days post-inoculation and goblet cell count at 14 days post-inoculation (p ≤ 0.05). Further, supplementation interacted with the microbiota modification led by the coccidiosis (p ≤ 0.05). These results suggest that this feed additive could be a useful strategy to reinforce the gut barrier, especially for birds under coccidiosis-challenge treatments.

A review of heat stress in chickens. Part I: Insights into physiology and gut health

Heat stress (HS) compromises the yield and quality of poultry products and endangers the sustainability of the poultry industry. Despite being homeothermic, chickens, especially fast-growing broiler lines, are particularly sensitive to HS due to the phylogenetic absence of sweat glands, along with the artificial selection-caused increase in metabolic rates and limited development of cardiovascular and respiratory systems. Clinical signs and consequences of HS are multifaceted and include alterations in behavior (e.g., lethargy, decreased feed intake, and panting), metabolism (e.g., catabolic state, fat accumulation, and reduced skeletal muscle accretion), general homeostasis (e.g., alkalosis, hormonal imbalance, immunodeficiency, inflammation, and oxidative stress), and gastrointestinal tract function (e.g., digestive and absorptive disorders, enteritis, paracellular barrier failure, and dysbiosis). Poultry scientists and companies have made great efforts to develop effective solutions to counteract the detrimental effects of HS on health and performance of chickens. Feeding and nutrition have been shown to play a key role in combating HS in chicken husbandry. Nutritional strategies that enhance protein and energy utilization as well as dietary interventions intended to restore intestinal eubiosis are of increasing interest because of the marked effects of HS on feed intake, nutrient metabolism, and gut health. Hence, the present review series, divided into Part I and Part II, seeks to synthesize information on the effects of HS on physiology, gut health, and performance of chickens, with emphasis on potential solutions adopted in broiler chicken nutrition to alleviate these effects. Part I provides introductory knowledge on HS physiology to make good use of the nutritional themes covered by Part II.

Cereal type and combined xylanase/glucanase supplementation influence the cecal microbiota composition in broilers

Dietary fiber-degrading enzyme supplementation in broilers aims at off-setting the anti-nutritive effect of non-starch polysaccharides and at promoting broiler health. Recently, we demonstrated that xylanase/glucanase addition in wheat-based diet improved nutrient digestibility, arabinoxylan fermentability and broiler growth. Conversely, maize arabinoxylan was found to be recalcitrant to xylanase action. These findings suggested that enzyme-mediated improvement of nutrient digestion and carbohydrate fermentation depended on the cereal type present in the diet, and may have contributed to broiler growth. Hence, we aimed at further investigating the link between dietary enzymes and carbohydrate fermentation in broilers, by studying the impact of enzyme supplementation in cereal-based diets, to the microbial communities in the ileum and ceca of broilers. For that purpose, 96 one-day-old male broilers were randomly reared in two pens and received either wheat-based or maize-based starter and grower diets. At d 20, the broilers were randomly assigned to one out of four dietary treatments. The broilers received for 8 d the wheat-based or maize-based finisher diet as such (Control treatments; WC, MC) or supplemented with a xylanase/glucanase combination (Enzyme treatments; WE, ME). At d 28, samples from the digestive tract were collected, and the ileal and cecal microbiota composition was determined by 16S ribosomal RNA gene amplicon sequencing. A similar phylogenetic (alpha) diversity was observed among the four treatments, both in the ileal and the cecal samples. Furthermore, a similar microbial composition in the ileum (beta diversity) was observed, with lactobacilli being the predominant community for all treatments. In contrast, both cereal type and enzyme supplementation were found to influence cecal communities. The type of cereal (i.e., wheat or maize) explained 47% of the total variation in microbial composition in the ceca. Further stratifying the analysis per cereal type revealed differences in microbiota composition between WC and WE, but not between MC and ME. Furthermore, the prevalence of beneficial genera, such as Faecalibacterium and Blautia, in the ceca of broilers fed wheat-based diets coincided with arabinoxylan accumulation. These findings indicated that fermentable arabinoxylan and arabinoxylo-oligosaccharides released by dietary xylanase may play an important role in bacterial metabolism.

Effects of Zinc Oxide Nanoparticles on Growth, Intestinal Barrier, Oxidative Status and Mineral Deposition in 21-Day-Old Broiler Chicks

This experiment was to study the effects of zinc oxide nanoparticles (ZnO-NPs) on growth, intestinal barrier, oxidative status, and mineral deposition. In total, 256 one-day-old chicks were randomly allotted to 4 dietary groups and fed with basal diet plus 80 mg/kg ZnSO₄ (ZnSO₄ group) or plus 40, 80, and 160 mg/kg ZnO-NPs, respectively, for 21 days. Compared with the ZnSO₄ group, dietary 40, 80, and 160 mg/kg ZnO-NPs did not alter growth (average daily gain, body weight, and gain to feed ratio), and serum activities of glutamic-pyruvic transaminase, alkaline phosphatase and glutamic oxalacetic transaminase (P > 0.05). However, dietary 80 and 160 mg/kg ZnO-NPs linearly decreased serum D-lactate content and diamine oxidase activity (P < 0.01). Moreover, 80 mg/kg ZnO-NPs enhanced zonula occludens-1 (ZO-1) mRNA expression in jejunal mucosa (P = 0.02). Dietary ZnO-NPs increased total antioxidant capacity activity (P = 0.01), and 80 mg/kg ZnO-NPs decreased malondialdehyde content in jejunal mucosa as compared to the ZnSO₄ group (P = 0.02). In contrast, dietary ZnO-NPs did not alter mRNA expressions of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, heme oxygennase-1 (HO-1) and NAD (P)H: quinone oxidoreductase 1 (NQO1) (P > 0.05). No significant difference was found in selected mineral concentrations (Mn, Cu, Fe and Zn) in the liver among ZnSO₄ and 3 ZnO-NP groups (P > 0.05). However, 160 mg/kg ZnO-NPs increased fecal contents of Zn, Fe and Cu (P < 0.01), but did not affect fecal Mn level (P > 0.05). Therefore, results suggested that ZnO-NPs could be an additive to enhance the intestinal barrier and antioxidant capacity of broiler chicks, whereas the inclusion of 80 mg/kg would be more efficient.

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

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

Bacillus subtilis inhibits intestinal inflammation and oxidative stress by regulating gut flora and related metabolites in laying hens

Bacillus subtilis is one of the most popular commercial probiotics used in farm animal production. However, its potential mechanisms are not very clear. The aim of this study was to investigate the effects of dietary Bacillus subtilis on intestinal histomorphology, innate immunity, microbiota composition, transcriptomics, and related metabolomics. Twenty-four 48-week-old Lohman Pink-shell laying hens were randomly divided into two groups: a basic diet and the basic diet supplemented with Bacillus subtilis (0.5 g/kg) for a 9-week experiment. At the end of the experiment, tissues of the duodenum, ileum, and jejunum as well as cecal content of each bird were collected for microstructure, PCR, transcriptome, metabolome, and 16S rRNA analyses. The results showed that dietary Bacillus subtilis supplement had no effect on the intestinal microstructure. However, Bacillus subtilis increased mRNA expression of tight junction protein occludin (P < 0.05), while reduced mRNA expression of lipopolysaccharide-induced TNF factor (P < 0.01) in the duodenum. Moreover, transcriptomic results indicated that most of Bacillus subtilis supplement-induced differential genes were associated with inflammation and immunity, including cytochrome b-245 beta chain, transferrin, and purinergic receptor P2X 7, resulting in a decrease in Malondialdehyde level (P < 0.05) in the duodenum. In addition, at the genus level, Bacillus subtilis supplement enriched the potential beneficial bacteria, Candidatus_Soleaferrea (P = 0.02) but inhibited the harmful bacteria including Lachnospiraceae_FCS020_group, Ruminiclostridium, Lachnospiraceae_UCG-010, and Oxalobacter. Metabolomic results revealed that N-Acetylneuraminic acid and ADP were increased by fed Bacillus subtilis. These results suggest that dietary Bacillus subtilis could inhibit gut inflammation and improve antioxidative status and barrier integrity of the duodenum via regulating gut microbial composition in laying hens.

Poultry gut health - microbiome functions, environmental impacts, microbiome engineering and advancements in characterization technologies

The gastrointestinal tract (GIT) health impacts animal productivity. The poultry microbiome has functions which range from protection against pathogens and nutrients production, to host immune system maturation. Fluctuations in the microbiome have also been linked to prevailing environmental conditions. Healthy poultry birds possess a natural resistance to infection. However, the exploration of environmental impacts and other relevant factors on poultry growth and health have been underplayed. Since good performance and growth rate are central to animal production, the host-microbiome relationship remains integral. Prior to the emergence of metagenomic techniques, conventional methods for poultry microbiome studies were used and were low-throughput and associated with insufficient genomic data and high cost of sequencing. Fortunately, the advent of high-throughput sequencing platforms have circumvented some of these shortfalls and paved the way for increased studies on the poultry gut microbiome diversity and functions. Here, we give an up-to-date review on the impact of varied environments on microbiome profile, as well as microbiome engineering and microbiome technology advancements. It is hoped that this paper will provide invaluable information that could guide and inspire further studies on the lingering pertinent questions about the poultry microbiome.

Effects of red-osier dogwood extracts on growth performance, intestinal digestive and absorptive functions, and meat quality of broiler chickens

A total of 320 one-day-old Cobb 500 chicks with an initial weight of 48.3 ± 3.3 g·pen−1 were assigned to four dietary treatments with eight replicates provided in three phases for 46 d. The treatments were fed as mash diets and included (1) negative control (NC) corn-soybean basal diet, (2) positive control (PC) basal diet with 30 ppm avilamycin, (3) basal diet supplemented with 1000 ppm red-osier dogwood extracts (RDE1), and (4) basal diet with 3000 ppm red-osier dogwood extracts (RDE2). Results showed reduced jejunal crypt depth in RDE1 and increased villus:crypt ratio in groups (either RDE1 or RDE2) (P < 0.05). Cationic amino acid (AA) transporter mRNA abundance was decreased (P < 0.05) in RDE1, RDE2, and PC treatments, but peptide and neutral AA transporter mRNA abundance were higher (P < 0.05) in RDE2 compared with NC. Apparent ileal digestibility of crude fat was increased in RDE2 and PC compared with NC, whereas AA digestibility was greater in RDE1, RDE2, and PC (P < 0.05). In conclusion, red-osier dogwood had no effect on growth performance, improved the intestinal health and function of broiler chickens, and had no detrimental effects on meat quality.

Effect of Pistacia lentiscus L. Vegetable Oil on Growth Performance and Coccidiosis in Broiler Chickens: In vitro and In vivo Assessment

This study aims to assess the ability of vegetable oil of Pistacia lentiscus L. (lentiscus oil) in stimulating growth performance of broiler chickens and protecting them against coccidiosis. For this purpose, an in vitro test was first carried out to evaluate the destructive effect of this oil on Eimeria spp oocysts. On the other hand, an in vivo study was carried out to evaluate, once again, the capacity of the vegetable oil of Pistacia lentiscus L. in stimulating broilers growth performance and reducing the coccidiosis clinical signs. Thus, day old chicks were randomly divided into four equal groups: (1) uninfected and not-supplemented control (NI NS); (2) uninfected and supplemented (NI S); (3) infected and not supplemented (I NS); (4) infected and supplemented (IS). Each group was divided into three replicates containing each of them two subjects. The experimental groups (2 and 4) are supplemented with lentiscus oil by force-feeding at the rate of 1 mL per day from the 18th day until the end of the experiment. The chicks of the third and the fourth group are inoculated orally with sporulated oocysts (6.5 × 105 oocysts of Eimeria spp) on the day 20 of age. The results showed that lentiscus oil has an anticoccidial dose-dependent effect as shown by oocysts counting and released substances measurement at 273 nm. The growth performance of the (NI S) group was found better with an improvement percentage of 9.14% compared to the control (p < 0.05). Likewise, the weight gain of the (I S) group seems slightly higher than that of the control one (1316 g and 1235 g, respectively) (p < 0.05). In conclusion, the vegetable oil of Pistacia lentiscus L. has shown, not only, a promising growth effect in broiler chickens, but also, it seems to have a protective effect against coccidiosis sequels caused by Eimeria acervulina infection.

Jejunal transcriptomic profiling of two layer strains throughout the entire production period

The jejunum plays crucial roles for the digestion and absorption of nutrients and minerals and for barrier functions that are essential for a healthy, productive life cycle of farm animals, including laying hens. Accordingly, knowledge of the molecular pathways that emerge in the intestine during development, and particularly at the beginning of laying activity, will help to derive strategies for improving nutrient efficiency in laying hens. In this study, jejunal samples were obtained from two high-yielding layer strains at five developmental stages (weeks 10, 16, 24, 30 and 60 of life) for RNA-sequencing, alongside the profiling of blood plasma parameters to approximate the dynamics of mineral homeostasis. The results reflected a marked distinction between the pre-laying and laying phase as inferred from levels of parathyroid hormone, triiodothyronine, estradiol, vitamin D, and calcium. Moreover, the expression patterns of the intestinal mucosa responded directly to the changing metabolic and nutritional profiles at the beginning of the laying phase in maturing high-yielding strains of laying hens. These comprise signaling events namely RANK/RANKL signaling and cellular senescence. Taken together, the timing of sexual maturity of laying hens demands closer examination to unravel metabolic requirements and associated endogenous mechanisms.

Limitation and Potential Effects of Different Levels of Aging Corn on Performance, Antioxidative Capacity, Intestinal Health, and Microbiota in Broiler Chickens

Simple Summary

Corn is an important ingredient and staple food in China; thus, corn storage has a certain importance to ensure domestic food resources. Normally, corn has been stored for 3 or more years under the proper storage conditions in national barns before it is used as a feed ingredient. This study aimed to investigate the effect of different levels of aging corn (AC) on performance, antioxidative capacity, intestinal health, and microbiota in broilers. In the present study, AC grains were stored for 4 years under the proper storage conditions at the national storage facility. The results indicated that a lower level of AC diet showed improved performance and overall bird health than a higher level of AC, and comparable with a normal corn diet. However, antioxidative capacity is reduced by AC diets.

Abstract

Three-hundred and sixty-day-old male broilers underwent three treatments with six replicates of 20 birds per treatment. The experimental diets included NC: normal corn diet; ACL: lower level (39.6–41.24%) of AC; and ACH: a higher level (56.99–59.12%) of AC. During phase 1 (0–21 d), broilers fed on AC showed lower (p < 0.05) body weight (BW), body weight gain (BWG), and feed conversion ratio (FCR) as compared with the NC group. During phase 2 (22–42 d), the NC group and ACL group showed better (p < 0.05) BW, BWG, and FCR than the ACH group. The footpad lesion score (p = 0.05) and litter moisture percentage (p < 0.05) were found to be higher in the ACH group. During phase 1, the ACL group showed a lower level of malondialdehyde (MDA) contents (p < 0.05) in serum; moreover, catalase (CAT) (p < 0.05) and glutathione peroxidase (GSH-Px) activities (p < 0.05) were found lower in both AC-containing groups. During phase 2, CAT activity in serum was found higher (p < 0.05) in the ACH group. During phase 1, the NC group showed higher CAT (p = 0.05), GSH-Px (p < 0.05), and superoxide dismutase (SOD) activity (p = 0.03); however, it showed lower MDA (p < 0.05) and total-antioxidative capability (T-AOC) (p < 0.05) in the liver. During phase 1, in breast muscle, CAT, SOD, and T-AOC were higher (p < 0.05) in the NC group. During phase 1, total cholesterol and high-density lipoprotein were found to be lower (p < 0.05) in the ACL group. Similarly, triglyceride and low-density lipoprotein were found to be lower (p < 0.05) in the ACL group than the ACH group. During phase 1, villus height was found to be higher (p < 0.05) in the ACH group. Moreover, the goblet cell (GC) was found to be higher (p < 0.05) in the NC group than the ACL group. During phase 2, GC was found to be higher (p < 0.05) in the ACL group. In ileal digesta, during phase 1, acetic acid, propionic acid, and butyric acid (BA) levels were found to be higher (p < 0.05) in the ACL group. In cecal digesta, BA was significantly lower (p < 0.05) in the NC group.

Current experimental models, assessment and dietary modulations of intestinal permeability in broiler chickens

Maintaining and optimising the intestinal barrier (IB) function in poultry has important implications for the health and performance of the birds. As a key aspect of the IB, intestinal permeability (IP) is mainly controlled by complex junctional proteins called tight junction proteins (TJ) that link enterocytes together. The disruption of TJ is associated with increased gut leakage with possible subsequent implications for bacterial translocation, intestinal inflammation, compromised health and performance of the birds. Despite considerable data being available for other species, research on IP in broiler chickens and in general avian species is still an understudied topic. This paper reviews the available literature with a specific focus on IP in broiler chickens with consideration given to practical factors affecting the IP, current assessment methods, markers and nutritional modulation of IP. Several experimental models to induce gut leakage are discussed including pathogens, rye-based diets, feed deprivation and stress-inducing agents such as exogenous glucocorticoids and heat stress. Although various markers including fluorescein isothiocyanate dextran, expression of TJ and bacterial translocation have been widely utilized to study IP, recent studies have identified a number of excreta biomarkers to evaluate intestinal integrity, in particular non-invasive IP. Although the research on various nutrients and feed additives to potentially modulate IP is still at an early stage, the most promising outcomes are anticipated for probiotics, prebiotics, amino acids and those feed ingredients, nutrients and additives with anti-inflammatory properties. Considerable research gaps are identified for the mechanistic mode of action of various nutrients to influence IP under different experimental models. The modulation of IP through various strategies (i.e. nutritional manipulation of diet) may be regarded as a new frontier for disease prevention and improving the health and performance of poultry particularly in an antibiotic-free production system.

Impact of Dietary or Drinking Water Ruminococcus sp. Supplementation and/or Heat Stress on Growth, Histopathology, and Bursal Gene Expression of Broilers

This research was conducted to evaluate the impact of dietary or drinking water Ruminococcus sp. supplementation and/or heat stress (HS) on the growth, serum biochemistry, tissue antioxidant, phagocytic assay, histopathology, and bursa gene expression of broilers. Day-old broiler chicks were allotted into six groups according to HS and/or Ruminococcus with or without enzyme supplementation. The first group was the control one, with a formulated diet and normal environmental temperature but without any supplement. The second group fed on Ruminococcus-supplemented diet (1 kg/kg diet). The third group fed on a formulated diet without supplement, and Ruminococcus and digestive enzymes were given in drinking water (0.1 ml/L). The fourth one was the heat stress group, with a normal formulated diet. The fifth and the sixth groups served as second and third groups, respectively, but with heat stress. The results of this experiment indicated that thermal temperature negatively affected the parameters of growth performance, serum biochemical, tissue antioxidants, and phagocytic assay. Moreover, heat stress led to pathological lesions in the internal organs and affected the expression of some genes related to heat stress, including proapoptotic genes such as caspase8 and bax, inflammatory genes such as NF-κβ1, and heat shock protein such as HSP 70 in the bursal tissue. These bad effects and abnormalities were mitigated by Ruminococcus alone or with enzyme supplementation, which improved all the above-mentioned parameters.

Novel Models for Chronic Intestinal Inflammation in Chickens: Intestinal Inflammation Pattern and Biomarkers

For poultry producers, chronic low-grade intestinal inflammation has a negative impact on productivity by impairing nutrient absorption and allocation of nutrients for growth. Understanding the triggers of chronic intestinal inflammation and developing a non-invasive measurement is crucial to managing gut health in poultry. In this study, we developed two novel models of low-grade chronic intestinal inflammation in broiler chickens: a chemical model using dextran sodium sulfate (DSS) and a dietary model using a high non-starch polysaccharide diet (NSP). Further, we evaluated the potential of several proteins as biomarkers of gut inflammation. For these experiments, the chemical induction of inflammation consisted of two 5-day cycles of oral gavage of either 0.25mg DSS/ml or 0.35mg DSS/ml; whereas the NSP diet (30% rice bran) was fed throughout the experiment. At four times (14, 22, 28 and 36-d post-hatch), necropsies were performed to collect intestinal samples for histology, and feces and serum for biomarkers quantification. Neither DSS nor NSP treatments affected feed intake or livability. NSP-fed birds exhibited intestinal inflammation through 14-d, which stabilized by 36-d. On the other hand, the cyclic DSS-treatment produced inflammation throughout the entire experimental period. Histological examination of the intestine revealed that the inflammation induced by both models exhibited similar spatial and temporal patterns with the duodenum and jejunum affected early (at 14-d) whereas the ileum was compromised by 28-d. Calprotectin (CALP) was the only serum protein found to be increased due to inflammation. However, fecal CALP and Lipocalin-2 (LCN-2) concentrations were significantly greater in the induced inflammation groups at 28-d. This experiment demonstrated for the first time, two in vivo models of chronic gut inflammation in chickens, a DSS and a nutritional NSP protocols. Based on these models we observed that intestinal inflammation begins in the upper segments of small intestine and moved to the lower region over time. In the searching for a fecal biomarker for intestinal inflammation, LCN-2 showed promising results. More importantly, calprotectin has a great potential as a novel biomarker for poultry measured both in serum and feces.