Evaluation the effect of dietary vitamin E, sesamin and thymoquinone bioactive compounds on immunological response, intestinal traits and MUC-2 gene expression in broiler Japanese quails (Coturnix japonica)

The current study was performed to determine the effect of dietary vitamin E, sesamin and thymoquinone bioactive lignans derived from sesame and black seed on immunological response, intestinal traits and Mucin2 gene expression in broiler quails. Three hundred and fifty (one days-old) quails were allotted to seven dietary treatments with five replicates as an experimental randomized design study. Treatments were basal diet as a control, control +100 and +200 mg of vitamin E, sesamin and thymoquinone per each kg of diet respectively. At 35 d of age, two quails from each pen were chosen, weighted, slaughtered, eviscerated and lymphoid organ relative weights were measured. Anti-body titers against Newcastle disease (ND), Sheep red blood cell (SRBC), and infectious bronchitis virus (IBV) and Avian influenza (AI) vaccination were determined. The serum activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and serum antioxidant activates such as superoxide dismutase (SOD),glutathione peroxidase(GPX), catalase (CAT) and total antioxidant capacity (TAC) were examined. The cell mediated immunity by dinitrochlorobenzene (DNCB) and phytohemagglutinin (PHA) challenges were assessed. The microflora populations of ileum, morphological traits of jejunum and mucin2 gene expression were analyzed. Data showed that the lymphoid organ (thymus, spleen and Bursa) relative weights and antibody titer against HI, AI, SRBC and IB vaccination were increased compared to the control (p ≤ 0.05). Serum activities of ALP, ALT and AST were decreased under influences of dietary treatments (p ≤ 0.05). The serum antioxidant activates of GPX,SOD,CAT and TAC were increased and Increasing in mean skin thickness after DNCB challenge and decrease wing web swelling response to PHA mitojen injection were observed (p ≤ 0.05). Salmonella enterica, E-coli and Coliforms colonies were decrease and Lactobacillus colonies increased instead (p ≤ 0.05). The villus height and surface, crypt depth and goblet cells density were increased compared to the control (p ≤ 0.05). The expression of MUC2 gene increased under influnces of vitamin E, sesamin and thymoquinone supplemented diets (p ≤ 0.05).

In ovo probiotic supplementation supports hatchability and improves hatchling quality in broilers

In modern broilers, the period of embryonic development constitutes a greater proportion of a broiler's productive life. Hence, optimum embryonic development can exert a significant influence not only on chick hatchability and hatchling quality but also on overall broiler growth and performance. Further healthy and active hatchlings are correlated with improved posthatch performance. In this regard, probiotics are good candidates to mediate early-life programming. Therefore, we evaluated the effect of In ovo probiotic spray application on broiler hatchability and hatchling quality. The experiment was set out as a completely randomized study with 2 independent trials. In each trial, 540 eggs (Ross 308) were either sprayed with phosphate buffered saline (PBS; control) or probiotics [∼9 log CFU/egg of Lactobacillus rhamnosus NRRL B-442(LR) or Lactobacillus paracasei DUP 13076 (LP)] during incubation. On day 18, eggs were transferred to the hatcher and set up for hatching. Starting on day 19, eggs were observed for hatching to determine the spread of hatch and hatchability. Hatched chicks were then assessed for quality using the Tona and Pasgar score and morphometric measurements including hatchling weight, yolk-free-body-mass and hatchling length were measured. Further, chicks were reared in floor pens for 3 wk to assess posthatch growth. Overall, In ovo probiotic supplementation improved hatchability and hatchling quality. Specifically, the spray application of LP improved hatchability by ∼ 5% without affecting the spread of hatch. Further, both LR and LP significantly improved Pasgar and Tona score, indicating an improvement in hatchling quality. Also, LP and LR significantly improved hatchling weight, yolk-free-body-mass, and posthatch growth in chicks. LR significantly improved hatchling weight and hatchling length (P < 0.05). Moreover, this increase in posthatch growth was positively correlated with hatchling weight in the probiotic groups. Overall, our study demonstrates that In ovo probiotic application exerts a positive effect on hatchability, hatchling quality, and subsequent posthatch growth.

Effects of Probiotic Lactiplantibacillus plantarum HJLP-1 on Growth Performance, Selected Antioxidant Capacity, Immune Function Indices in the Serum, and Cecal Microbiota in Broiler Chicken

This research study aimed to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) on growth performance, oxidation resistance, immunity, and cecal microbiota in broilers. This work classed three hundred and sixty 1-day-old male broilers into three groups randomly, including a control group (CON, basal diet) and antibiotic (ANT, 75 mg kg-1 chlortetracycline added into basal diet) and probiotic groups (LP, 5 × 108 CFU kg-1Lactiplantibacillus plantarum HJLP-1 contained within basal diet). Animals were then fed for 42 days, and each group comprised eight replicates with 15 broilers. Compared with CON, L. plantarum supplementation significantly improved the average daily weight gain (AWDG) (p < 0.05) while reducing the feed-gain ratio over the entire supplemental period (p < 0.05). Birds fed L. plantarum had markedly lower serum ammonia and xanthine oxidase levels (p < 0.05) than those in the ANT and CON groups. Significant improvements (p < 0.05) in superoxide dismutase, catalase, and serum IgM and IgY contents in broilers fed L. plantarum were also observed when compared with those in the CON and ANT groups. Both L. plantarum and antibiotics decreased pro-inflammatory factor IL-1β levels significantly (p < 0.05), while only L. plantarum promoted anti-inflammatory factor IL-10 levels in the serum (p < 0.05) compared with CON. L. plantarum (p < 0.05) increased acetic acid and butyric acid concentrations in cecal contents when compared to those in CON and ANT. Among the differences revealed via 16S rRNA analysis, L. plantarum markedly improved the community richness of the cecal microbiota. At the genus level, the butyric acid-producing bacteria Ruminococcus and Lachnospiraceae were found in higher relative abundance in samples of L. plantarum-treated birds. In conclusion, dietary L. plantarum supplementation promoted the growth and health of broilers, likely by inducing a shift in broiler gut microbiota toward short-chain fatty acid (SCFA)-producing bacteria. Therefore, L. plantarum has potential as an alternative to antibiotics in poultry breeding.

Integrated multi-omics reveals the roles of cecal microbiota and its derived bacterial consortium in promoting chicken growth

IMPORTANCE

The improvement of chicken growth performance is one of the major concerns for the poultry industry. Gut microbes are increasingly evidenced to be associated with chicken physiology and metabolism, thereby influencing chicken growth and development. Here, through integrated multi-omics analyses, we showed that chickens from the same line differing in their body weight were very different in their gut microbiota structure and host-microbiota crosstalk; microbes in high body weight (HBW) chickens contributed to chicken growth by regulating the gut function and homeostasis. We also verified that a specific bacterial consortium consisting of isolates from the HBW chickens has the potential to be used as chicken growth promoters. These findings provide new insights into the potential links between gut microbiota and chicken phenotypes, shedding light on future manipulation of chicken gut microbiota to improve chicken growth performance.

Effect of Cyberlindnera jadinii yeast on growth performance, nutrient digestibility, and gut health of broiler chickens from 1 to 34 d of age

The effect of dietary graded levels of Cyberlindnera jadinii yeast (C. jadinii) on growth performance, nutrient digestibility, and gut health of broilers was evaluated from 1 to 34 d of age. A total of 360 male broiler chicks were randomly allocated to 1 of 4 dietary treatments (6 replicate pens each) consisting of a wheat-soybean meal-based pelleted diet (Control or CJ0), and 3 diets in which 10% (CJ10), 20% (CJ20), and 30% (CJ30) of the crude protein were supplied by C. jadinii, by gradually replacing protein-rich ingredients. Body weight and feed intake were measured at d 1, 11, 22, and 32. Pellet temperature, durability, and hardness increased linearly (P < 0.05) with C. jadinii inclusion, with highest (P < 0.05) values for CJ30. Up until d 22, feed conversion ratio (FCR) was similar between treatments (P = 0.169). Overall, increasing C. jadinii inclusion linearly increased (P = 0.047) feed intake but had no effect on weight gain or mortality. FCR increased (P < 0.05) linearly with increasing C. jadinii inclusion but only birds fed CJ30 had a significantly poorer FCR compared to the Control. Ileal digestibility was not affected by C. jadinii inclusion, however, there was a significant linear decrease in crude protein and phosphorus, and a tendency for a decrease in fat digestibility. Apparent metabolizable energy (AME) decreased (P < 0.001) quadratically with increasing C. jadinii and was significantly lower in CJ30 compared to the Control. Ileal concentrations of volatile fatty acids (VFAs) were not affected by C. jadinii inclusion, but butyric acid and total VFAs were linearly and quadratically increased and were significantly higher in cecal digesta of birds fed CJ20 and CJ30. Increasing C. jadinii inclusion was associated with an increase (P < 0.05) in the relative abundance of lactobacillus in the ileum and cecum. In conclusion, C. jadinii yeast can supply up to 20% of the total dietary protein without negatively affecting performance, digestibility, or gut health of broilers. The potential confounding role of feed processing and C. jadinii cell wall components on broiler performance is discussed.

The protective effects of Bacillus licheniformis against inflammatory responses and intestinal barrier damage in broilers with necrotic enteritis induced by Clostridium perfringens

BACKGROUND

Bacillus licheniformis is a gram-positive bacterium that has strong environmental adaptability and can improve the growth performance, immunity, and antioxidant function of broilers. The current study aimed to elucidate the protective capability of B. licheniformis against inflammatory responses and intestinal barrier damage in broilers with necrotic enteritis (NE) induced by Clostridium perfringens (CP).

RESULTS

The results showed that B. licheniformis enhanced the final body weight in broilers compared with that of broilers in the CP group after the stress of infection (P < 0.05). Bacillus licheniformis reversed the decreased levels of serum and jejunum mucosa immunoglobulins and anti-inflammatory cytokines, reduced the values of villus height and the ratio of villus height to crypt depth, and mitigated the increased levels of serum d-lactic acid and diamine oxidase in CP-challenged broilers (P < 0.05). Moreover, B. licheniformis modulated the expression levels of genes involved in the TLR4/NF-κB signalling pathway, the NLRP3 inflammasome activation pathway, and the sirt 1/Parkin signalling pathway in CP-challenged broilers. Compared with the CP challenge group, the B. licheniformis-treated group exhibited reduced abundance values of Shuttleworthia and Alistipes and enhanced abundance values of Parabacteroides in the caecal contents (P < 0.05).

CONCLUSION

Bacillus licheniformis improved the final body weight and alleviated the inflammatory response and intestinal barrier function damage in birds with NE induced by CP by maintaining intestinal physiological function, enhancing immunity, regulating inflammatory cytokine secretion, modulating the mitophagy response, and increasing the abundance of beneficial intestinal flora. © 2023 Society of Chemical Industry.

Effects of a novel, non-invasive pre-hatch application of probiotic for broilers on development of cecum microbiota and production performance

BACKGROUND

Probiotics are used in the broiler industry to increase production performance. Most often a probiotic is applied by mixing it in the feed, but studies have shown that earlier application may be advantageous. Therefore, in ovo application where the probiotic is administrated into the egg before hatch has been investigated as an alternative application method. However, in ovo application may impact hatchability negatively and may not be feasible at all hatcheries. The purpose of this study was to investigate the effect of a novel non-invasive method for mass application before hatch. The probiotic (E. faecium 669) was applied as a single dose by spray on the unhatched eggs and production performance and development of the cecal microbiota until slaughter was compared with a control flock. Through 16S rRNA sequencing of cecal samples from 25 broilers at day 7, 21 and 37 we compared the microbiota composition and richness for each group. The study was repeated for additional recording of production performance and re-isolation of the probiotic E. faecium from the intestine.

RESULTS

In both trials the probiotic E. faecium could be re-isolated from the yolk sac and intestine at hatch and at day 7. Broilers in the probiotic treated groups had a higher performance in terms of bodyweight at day 34 and European production efficiency factor. Finally, a significant reduction of first-week and overall mortality was observed in the probiotic group in the first trial. Based on 16S rRNA profiling, significant differences in alpha diversity were found exclusively at day 37. Estimation of beta diversities, however, identified significant differences in microbiota composition between the control and probiotic group at day 7, 21 and 37.

CONCLUSION

The probiotic E. faecium strain successfully colonized broilers before/during hatch after a single spray application at day 18 of incubation. Positive effects of the probiotic were observed in multiple production parameters, including reduced mortality in trial 1, and microbiota analyses indicate significantly different microbiota compositions throughout the experimental phase. Taken together, the novel low-tech mass administration of E. faecium (669) may be considered a feasible strategy for improvements of production parameters in broiler production.

Human Salmonellosis: A Continuous Global Threat in the Farm-to-Fork Food Safety Continuum

Salmonella is one of the most common zoonotic foodborne pathogens and a worldwide public health threat. Salmonella enterica is the most pathogenic among Salmonella species, comprising over 2500 serovars. It causes typhoid fever and gastroenteritis, and the serovars responsible for the later disease are known as non-typhoidal Salmonella (NTS). Salmonella transmission to humans happens along the farm-to-fork continuum via contaminated animal- and plant-derived foods, including poultry, eggs, fish, pork, beef, vegetables, fruits, nuts, and flour. Several virulence factors have been recognized to play a vital role in attaching, invading, and evading the host defense system. These factors include capsule, adhesion proteins, flagella, plasmids, and type III secretion systems that are encoded on the Salmonella pathogenicity islands. The increased global prevalence of NTS serovars in recent years indicates that the control approaches centered on alleviating the food animals' contamination along the food chain have been unsuccessful. Moreover, the emergence of antibiotic-resistant Salmonella variants suggests a potential food safety crisis. This review summarizes the current state of the knowledge on the nomenclature, microbiological features, virulence factors, and the mechanism of antimicrobial resistance of Salmonella. Furthermore, it provides insights into the pathogenesis and epidemiology of Salmonella infections. The recent outbreaks of salmonellosis reported in different clinical settings and geographical regions, including Africa, the Middle East and North Africa, Latin America, Europe, and the USA in the farm-to-fork continuum, are also highlighted.

Bacillus subtilis DSM29784 attenuates Clostridium perfringens-induced intestinal damage of broilers by modulating intestinal microbiota and the metabolome

Necrotic enteritis (NE), especially subclinical NE (SNE), without clinical symptoms, in chicks has become one of the most threatening problems to the poultry industry. Therefore, increasing attention has been focused on the research and application of effective probiotic strains as an alternative to antibiotics to prevent SNE in broilers. In the present study, we evaluated the effects of Bacillus subtilis DSM29784 (BS) on the prevention of subclinical necrotic enteritis (SNE) in broilers. A total of 480 1-day-old broiler chickens were randomly assigned to four dietary treatments, each with six replicates pens of twenty birds for 63 d. The negative (Ctr group) and positive (SNE group) groups were only fed a basal diet, while the two treatment groups received basal diets supplemented with BS (1 × 109 colony-forming units BS/kg) (BS group) and 10mg/kg enramycin (ER group), respectively. On days 15, birds except those in the Ctr group were challenged with 20-fold dose coccidiosis vaccine, and then with 1 ml of C. perfringens (2 × 108) at days 18 to 21 for SNE induction. BS, similar to ER, effectively attenuated CP-induced poor growth performance. Moreover, BS pretreatment increased villi height, claudin-1 expression, maltase activity, and immunoglobulin abundance, while decreasing lesional scores, as well as mucosal IFN-γ and TNF-α concentrations. In addition, BS pretreatment increased the relative abundance of beneficial bacteria and decreased that of pathogenic species; many lipid metabolites were enriched in the cecum of treated chickens. These results suggest that BS potentially provides active ingredients that may serve as an antibiotic substitute, effectively preventing SNE-induced growth decline by enhancing intestinal health in broilers.

Comparison of the effects of probiotic-based formulations on growth, feed utilization, blood constituents, cecal fermentation, and duodenal morphology of rabbits reared under hot environmental conditions

The present study aimed to assess the effects of three probiotic-supplemented diets on growth, cecal fermentation, blood biochemical, and intestinal morphological features in growing rabbits reared under summer conditions. Rabbits were allotted into four groups: G1 rabbits were fed the basal diet (control), G2 rabbits received Enterococcus faecium (EF) and Clostridium butyricum (CB) complexes (1 × 108 and 2.5 × 106 cfu/kg diet, respectively), G3 rabbits were given CB (2.5 × 106 cfu/kg diet) and yeast complexes (1 g/kg diet), and G4 rabbits received EF (2 × 108 cfu/kg diet) and yeast (1 g/kg diet). G2 rabbits exhibited the highest performances in terms of enhanced body weight and weight gain, protein efficiency ratio and feed conversion ratio (P<0.05). Serum total protein, globulin, immunoglobulin M, and high-density lipoprotein concentrations were higher in probiotic-fed rabbits than those in controls. Additionally, lipid profile parameters were significantly reduced in the probiotic-fed rabbits, with the lowest concentrations measured in G4 rabbits (P<0.05). Rabbits given EF and CB had the highest total volatile fatty acid (VFA) and propionic acid levels and the lowest ammonia concentrations. Increased villi length and muscular layer thickness and reduced crypt depth were observed in rabbits receiving EF and CB compared with the values obtained in controls (P<0.05). In summary, supplementing fattening rabbit diets with EF and CB, as a novel formulation, might be a promising and easy method to enhance growth performance under hot climate conditions by improving the feed utilization, immune response, serum lipid profile, cecal VFA production, and duodenal morphology.

Citric Acid and Magnolol Ameliorate Clostridium perfringens Challenge in Broiler Chickens

Clostridium perfringens (C. perfringens) is a common pathogenic bacterium implicated in the enteric diseases of animals. Each year, the disease is responsible for billions of dollars of losses worldwide. The development of new phytomedicines as alternatives to antibiotics is becoming a new hotspot for treating such diseases. Citric acid (CA) and magnolol (MA) have been shown to have antibacterial, antioxidant, and growth-promoting properties. Here, the bacteriostatic effects of combinations of CA and MA against C. perfringens were investigated, together with their effects on yellow-hair chickens challenged with C. perfringens. It was found that the optimal CA:MA ratio was 50:3, with a dose of 265 μg/mL significantly inhibiting C. perfringens growth, and 530 μg/mL causing significant damage to the bacterial cell morphology. In animal experiments, C. perfringens challenge reduced the growth, damaged the intestinal structure, activated inflammatory signaling, impaired antioxidant capacity, and perturbed the intestinal flora. These effects were alleviated by combined CA-MA treatment. The CA-MA combination was found to inhibit the TLR/Myd88/NF-κB and Nrf-2/HO-1 signaling pathways. In conclusion, the results suggest the potential of combined CA-MA treatment in alleviating C. perfringens challenge by inhibiting the growth of C. perfringens and affecting the TLR/MyD88/NF-κB and Nrf-2/HO-1 signaling pathways.

Conversion of Phenolic Acids in Canola Fermentation: Impact on Antimicrobial Activity against Salmonella enterica and Campylobacter jejuni

Canola meal (CM) is commonly used in poultry feeds. CM has a high protein content but also contains high levels of antimicrobial phenolic acids. Lactic acid bacteria can alter CM phenolic composition during fermentation and influence its antimicrobial activity against pathogens. Fermented CM was analyzed for phenolic composition using tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography (HPLC). Sinapic acid and derivatives were the major phenolic acids in CM. Growth of lactobacilli in CM was attenuated when compared to cereal substrates. Glucosides and esters of sinapic acid were extensively hydrolyzed during fermentation with Lactiplantibacillus plantarum and Furfurilactobacillus milii. Lp. plantarum transformed hydroxycinnamic acids to dihydro, 4-vinyl, and 4-ethyl derivatives, Ff. milii reduced hydroxycinnamic acids to dihydroderivatives, but Limosilactobacillus reuteri did not convert hydroxycinnamic acids. The minimum inhibitory concentration of phenolic extracts was assessed with lactobacilli, Salmonella, and Campylobacter jejuni as indicator strains. Fermentation of CM with Lp. plantarum or Ff. milii increased the antimicrobial activity of phenolic extracts against Salmonella enterica and Campylobacter jejuni. Fermentation with Lm. reuteri TMW1.656 but not fermentation with Lm. reuteri TMW1.656ΔrtcN increased the antimicrobial activity of extracts owing to the production of reutericyclin. This study demonstrates that fermentation of CM with lactobacilli converts hydroxycinammic esters and may increase the antimicrobial activity of phenolic compounds in CM against pathogens.

Effects of Lactobacillus fermentum Administration on Intestinal Morphometry and Antibody Serum Levels in Salmonella-Infantis-Challenged Chickens

There are no studies reporting the effects of Salmonella enterica subsp. enterica serovar Infantis (S. Infantis) on intestinal architecture and immunoglobulin serum levels in chickens. Here, we measured these parameters and hypothesized whether probiotic administration could modulate the observed outcomes. Two-hundred 1-day-old COBB 500 male chicks were allocated into four groups: (I) the control, (II) the group treated with L. fermentum, (III) the group exposed to S. Infantis, and (IV) the group inoculated with both bacteria. At 11 days post infection, blood was gathered from animals which were then euthanized, and samples from the small intestine were collected. Intestinal conditions, as well as IgA and IgM serum levels, were assessed. S. Infantis reduced villus-height-to-crypt-depth (VH:CD) ratios in duodenal, jejunal, and ileal sections compared to control conditions, although no differences were found regarding the number of goblet cells, muc-2 expression, and immunoglobulin concentration. L. fermentum improved intestinal measurements compared to the control; this effect was also evidenced in birds infected with S. Infantis. IgM serum levels augmented in response to the probiotic in infected animals. Certainly, the application of L. fermentum elicited positive outcomes in S. Infantis-challenged chickens and thus must be considered for developing novel treatments designed to reduce unwanted infections.

Digital livestock systems and probiotic mixtures can improve the growth performance of swine by enhancing immune function, cecal bacteria, short-chain fatty acid, and nutrient digestibility

In response to climate change, the use of digital livestock systems and probiotic mixtures as technological strategies to improve animal health and production is driving new innovations in the farm animal industry. However, there is little information available regarding the effects of digital livestock systems and probiotic mixtures (consisting of Bacillus subtillus, Streptomyces galilaeus, and Sphingobacteriaceae) on the growth performance of the growth-finishing swine. Thus, the objective of this study was to investigate the effects of digital livestock systems and probiotic mixtures on the immune function, cecal bacteria, short-chain fatty acids, nutrient digestibility, and growth performance of growth-finishing swine. A total of 64 crossbred male swine (Duroc × Landrace × Yorkshire, average body weight: 60.17 ± 1.25 kg) were randomly assigned to four treatment groups: CON (control group with a conventional livestock system without a probiotic mixture), CON0.4 (a conventional livestock system with a 0.4% probiotic mixture), DLSC (a digital livestock system without a probiotic mixture), and DLS0.4 (a digital livestock system with a 0.4% probiotic mixture). The swine were reared under standard environmental conditions until their average body weight reached 110 kg. The results indicated that the growth performance of the swine improved with an increase in nutrient digestibility and immune function via modulation of blood immune markers in the group with a digital livestock system compared to the CON group, although the growth performance of the swine was similar between the DLSC and CON0.4 groups. Moreover, the application of the digital livestock system and the probiotic mixture maintained higher levels of Lactobacillus and balanced short-chain fatty acid profiles compared to the CON group. These results suggest that a digital livestock system and a probiotic mixture can improve the growth performance of swine by enhancing their nutrient digestibility, improving their immune function, and maintaining balanced cecal bacteria and short-chain fatty acids. Therefore, this study provides insights into the application of digital livestock systems and probiotic mixtures as a climate change response strategy to improve swine production.

Screening and characterization of Bacillus velezensis LB-Y-1 toward selection as a potential probiotic for poultry with multi-enzyme production property

Bacillus spp. have gained increasing recognition as an option to use as antimicrobial growth promoters, which are characterized by producing various enzymes and antimicrobial compounds. The present study was undertaken to screen and evaluate a Bacillus strain with the multi-enzyme production property for poultry production. LB-Y-1, screened from the intestines of healthy animals, was revealed to be a Bacillus velezensis by the morphological, biochemical, and molecular characterization. The strain was screened out by a specific screening program, possessed excellent multi-enzyme production potential, including protease, cellulase, and phytase. Moreover, the strain also exhibited amylolytic and lipolytic activity in vitro. The dietary LB-Y-1 supplementation improved growth performance and tibia mineralization in chicken broilers, and increased serum albumin and serum total protein at 21 days of age (p < 0.05). Besides, LB-Y-1 enhanced the activity of serum alkaline phosphatase and digestive enzyme in broilers at 21 and 42 days of age (p < 0.05). Analysis of intestinal microbiota showed that a higher community richness (Chao1 index) and diversity (Shannon index) in the LB-Y-1 supplemented compared with the CON group. PCoA analysis showed that the community composition and structure were distinctly different between the CON and LB-Y-1 group. The beneficial genera such as Parasutterella and Rikenellaceae were abundant, while the opportunistic pathogen such as Escherichia-Shigella were reduced in the LB-Y-1 supplemented group (p < 0.05). Collectively, LB-Y-1 can be considered as a potential strain for further utilization in direct-fed microbial or starter culture for fermentation.

Bacillus subtilis and Pichia farinose mixture improves growth performance and nutrient absorption capacity in broiler chicks

Introduction

This study evaluated the effects of dietary supplementation of Bacillus subtilis and Pichia farinose mixture (BPM) on growth performance, apparent ileal digestibility, cecal bacteria counts, small intestinal morphology and digestive enzymes activities, and jejunal nutrient transporters gene expression in broiler chicks.

Methods

A total of 768 one-day-old Ross 308 broiler chicks were randomly Q18 assigned into 3 groups based on the initial body weight (42.00 ± 0.08 g). The experimental periods were 35 days. There were 16 replicates per group and 16 birds per cage. Dietary treatments included a basal diet supplemented with 0, 0.1, or 0.2% BPM to form CON, BPM0.1 (consisting Bacillus subtilis with 1.0 × 107 viable spore and Pichia farinose with 1.0 × 107 viable spore per kg diet), and BPM0.2 (consisting Bacillus subtilis with 2.0 × 107 viable spore and Pichia farinose with 2.0 × 107 viable spore per kg diet) groups.

Results and discussion

Dietary supplementation of graded levels of BPM has positive effects on growth performance of broiler chicks, manifesting in the increase of body weight gain during days 1-35 as well as the decrease of feed conversion ratio during days 1-7, 21-35, and 1-35. Moreover, BPM supplementation positively improved ileal energy and crude protein digestibility, increased Lactobacillus counts, optimized intestinal morphology, enhanced intestinal digestive enzymes activities, and upregulated jejunal SGLT-1, GLUT-2, and PEPT-1 expression. Therefore, BPM supplementation improved growth performance of broiler chicks, which was partially related to the improvement in intestinal nutrient absorption capacity.

Probiotics in Poultry Nutrition as a Natural Alternative for Antibiotics

Since the early 1950s, antibiotics have been used in poultry for improving feed efficiency and growth performance. Nevertheless, various side effects have appeared, such as antibiotic resistance, antibiotic residues in eggs and meat, and imbalance of beneficial intestinal bacteria. Consequently, it is essential to find other alternatives that include probiotics that improve poultry production. Probiotics are live microorganisms administered in adequate doses and improve host health. Probiotics are available to be used as feed additives, increasing the availability of the nutrients for enhanced growth by digesting the feed properly. Immunity and meat and egg quality can be improved by supplementation of probiotics in poultry feed. Furthermore, the major reason for using probiotics as feed additives is that they can compete with various infectious diseases causing pathogens in poultry's gastrointestinal tract. Hence, this chapter focuses on the types and mechanisms of action of probiotics and their benefits, by feed supplementation, for poultry health and production.

Host-specific probiotics feeding influence growth, gut microbiota, and fecal biomarkers in buffalo calves

The current study is aimed to evaluate the effect of host-specific probiotics on the gut microbiome, performance, and select fecal biomarkers of gut health in preruminant buffalo calves. Eight Murrah buffalo calves (3–5 days old; 32.52 ± 0.43 kg average body weight (BW)) were randomly allocated into two groups as follows; 1) Group I (n = 4) fed basal diet alone (CON); 2) Group II (n = 4) supplemented with a lyophilized probiotic formulation at a dose rate of 1 g/day/head (1 × 10⁹ CFU/g) having Limosilactobacillus reuteri BF-E7 and Ligilactobacillus salivarius BF-17 along with basal diet (PF) for 30 days. Results revealed that final BW (kg), average daily gain (g/day), average dry matter intake (g/day), and structural growth measurements were significantly (P < 0.05) increased in the probiotics supplemented group (PF) compared to the control (CON). Fecal pH, fecal moisture, and fecal score were reduced (P < 0.05) in PF than in CON. Moreover, levels of fecal propionate, lactate, and ammonia altered positively in PF compared with CON. The relative abundance of Firmicutes tended to be higher (P = 0.10) in the probiotics fed group than CON. However, the relative abundance of Proteobacteria was significantly lower (P = 0.03) for calves fed probiotics on day 15. A trend was observed in Bacteroides (P = 0.07) and Lactobacillus (P = 0.08) abundances in the feces of the PF than in CON. Overall, it can be concluded that the administration of probiotic formulations significantly improved the performance and gut health of buffalo calves via modulating the gut microbiota composition.

Comparison of Therapeutic Antibiotics, Probiotics, and Synthetic CpG-ODNs for Protective Efficacy Against Escherichia coli Lethal Infection and Impact on the Immune System in Neonatal Broiler Chickens

The poultry industry needs alternatives to antibiotics, as there are growing public concerns about the emergence of antimicrobial resistance owing to antimicrobial use in animal production. We have reported that the administration of neonatal chicks with synthetic DNA oligodeoxynucleotides containing unmethylated cytosine guanine dinucleotide (CpG) motifs (CpG-ODN) can protect against bacterial pathogens in chickens. The objective of this study was to compare the immunoprotective effects of CpG-ODN and probiotics against Escherichia coli infection vs. commonly used therapeutic antibiotics. Day-old broiler chicks were divided into five groups (n = 35/group; 30 for the challenge experiment and 5 for the flow cytometry analysis). The chicks in Group 1 received a single dose of CpG-ODN by the intramuscular route on day 4 (D4) posthatch (PH), and Group 2 received drinking water (DW) with a probiotic product (D1-D15 PH, DW). The Group 3 chicks received tetracycline antibiotics during D9-D13 in DW; the Group 4 chicks got sodium sulfamethazine on D9, D10, and D15 PH in DW; and the Group 5 chicks were administered intramuscular (IM) saline D4 PH, DW. We challenged all the groups (n = 30/group) with E. coli (1 × 10⁵ or 1 × 10⁶ colony-forming units/bird) on D8 PH through the subcutaneous route. Our data demonstrated that the CpG-ODNs, but not the probiotics, could protect neonatal broiler chickens against lethal E. coli septicemia, as would the tetracycline or sodium sulfamethazine. The flow cytometry analysis (n = 5/group) revealed enrichment of immune cells in the CpG-ODN group and a marked decrease in macrophages and T-cell numbers in antibiotics-treated groups, indicating immunosuppressive effects. Our data showed that, like therapeutic antibiotics, CpG-ODNs reduced clinical signs, decreased bacterial loads, and induced protection in chicks against E. coli septicemia. Unlike therapeutic antibiotics-induced immunosuppressive effects, CpG-ODN caused immune enrichment by increasing chicken immune cells recruitment. Furthermore, this study highlights that, although therapeutic antibiotics can treat bacterial infections, the ensuing immunosuppressive effects may negatively impact the overall chicken health.

Effects of three probiotics and their interactions on the growth performance of and nutrient absorption in broilers

The purpose of this study was to investigate the effects of three probiotics and their interactions on growth performance, intestinal digestion and absorption, and nutrient transporters in broilers. A total of 350 one-day-old male Arbor Acres broilers were randomly divided into seven groups: the control group (broilers receiving normal drinking water), groups P1, P2 and P3 (broilers receiving drinking water with 1% Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium lactis , respectively) and groups CP1, CP2 and CP3 (broilers receiving drinking water with a 1% compound probiotic mixture in 2:1:1, 1:2:1, 1:1:2 ratios, respectively). The feeding period was divided into two experimental periods: 1∼21 days and 22∼42 days. Compared to those in the control group, the broiler slaughter indexes and average daily feed intakes in the probiotics groups were not significantly different (P > 0.05), but the villus height in the small intestine increased significantly, and the crypt depth decreased significantly (P < 0.05). In the 1- to 21-day, experimental period, the broiler average daily gains in groups CP2 and CP3 were significantly greater than that in the control group. Amylase, lipase, and trypsin activities in the jejunum in groups CP and P3 increased significantly. GLUT2 mRNA expression in the probiotics group was significantly incresaed compared with that in the control group (P < 0.05). In the 22- to 42-day period, the average daily gain in the CP group was significantly greater than that in the control group. Amylase activity in the CP2 group, and lipase and trypsin activities in the CP, P1 and P3 groups increased significantly. The GLUT2 mRNA expression in the CP group increased significantly (P < 0.05). In summary, three probiotics and their interactions improved the digestibility and absorption of nutrients by increasing the activities of digestive enzymes, improving the morphology of the digestive tract, and upregulating the expression of GLUT2 mRNA in the intestinalcell membrane to improve the production performance in broilers.

Effect of β-Mannanase Supplementation on Growth Performance, Ileal Digestibility, Carcass Traits, Intestinal Morphology, and Meat Quality in Broilers Fed Low-ME Diets

Experiment was designed to analyze the effect of low caloric diets, supplemented with β-mannanase on growth performance, carcass characteristics, nutrient digestibility, and other parameters in broilers. In this study, 400 broiler chicks were randomly divided into four treatments (Cont: without β-mannanase; LM-30, MM-60, and HM-90: supplemented with 200, 400, and 600 mg/kg β-mannanase, respectively). Dietary metabolizable energy (ME) in Cont was standard (starter diet 3100 kcal/kg; finisher diet 3200 kcal/kg) and reduced by 30, 60, and 90 kcal/kg, correspondingly in β-mannanase-supplemented treatments. The results exhibited that growth performance was not affected by reducing dietary energy levels with supplementation of β-mannanase. Ileal digestibility of DM and CF was improved (p < 0.01) by supplementation of β-mannanase at low dietary ME levels. Concerning carcass traits, the relative weight of breast meat, drumstick, and abdominal fat increased (p < 0.05) with β-mannanase supplementation in low-ME diets. Treatment HM-90 showed significantly (p < 0.05) better results regarding villus height and VH:CD. It could be concluded from the present results that supplementation of β-mannanase could improve the nutrient digestibility so that it is possible to reduce the dietary energy level without compromising production performance, carcass trails, and meat quality in broilers.

Effects of glucose oxidase and its combination with B. amyloliquefaciens SC06 on intestinal microbiota, immune response and antioxidative capacity in broilers

Glucose oxidase (GOD) is an aerobic dehydrogenase, which catalyses the oxidation of β-D-glucose to gluconic acid and hydrogen peroxide. This study aimed to investigate the effects of dietary glucose oxidase and its combined effects with Bacillus amyloliquefaciens SC06 (BaSC06) on the intestinal microbiota, immune function and antioxidant capacity of broilers. One-day-old male Lingnan yellow-feathered broilers (n = 720) were randomly assigned to four treatment groups: Control group (basal diet), Anti group (basal diet supplemented with 200 mg/kg enramycin), GOD group (basal diet supplemented with 75 U/kg GOD), and combination of GOD and BaSC06 (GB) group (GOD diet (75 U/kg) supplemented with 1 × 10⁸ colony-forming units BaSC06/kg feed), with six replicates per group and 30 birds per replicate. The experiment was conducted over 52 days. The results indicated a significant decrease in α-diversity (Observed species, Chao1, PD_whole_tree and Shannon) with GOD treatment, compared with the control group. GB treatment also significantly decreased the Shannon index of cecal microbiota. GOD treatment significantly decreased the α-diversity, whereas GB treatment significantly increased these indices except for the Chao1 index, compared with the Anti group. Compared with the control group, the relative abundance of Bacteroides in the GOD and GB groups was significantly increased, whereas a decrease in Firmicutes was observed. Compared with the Anti group, GOD treatment significantly increased the relative abundances of Bacteroides and Lactobacillales, while GB treatment significantly increased Lactobacillales and decreased Proteobacteria levels. In addition, GOD treatment significantly decreased interleukin-10 and interferon-γ levels, compared with the control group. In contrast, GB treatment significantly downregulated interferon-γ levels and upregulated secretory immunoglobulin A, transforming growth factor-β and interleukin-2 expression in the jejunal mucosa. GOD treatment significantly decreased transforming growth factor-β and interleukin-10 levels, whereas GB treatment markedly increased interferon-γ expression in the jejunal mucosa compared with the Anti group. Furthermore, GB treatment significantly increased the total antioxidant capability levels and the total superoxide dismutase (T-SOD) and catalase (CAT) activities compared with the control group. Meanwhile, GOD treatment significantly increased glutathione peroxidase (GSH-Px) activity in the jejunal mucosa. Total superoxide dismutase, GSH-Px and CAT activities in the Anti group were higher than in the GOD and GB groups. The malondialdehyde levels in the control group were the highest among all groups. In conclusion, our results indicated that supplementation with GOD alone and its combination with BaSC06 in diet could increase antioxidant capacity, immune function and improve the intestinal microbiota composition of broilers. Combination treatment with GOD with BaSC06 exerted stronger effects than GOD treatment only.

Bacteriophage therapy as an alternative biocontrol against emerging multidrug resistant E. coli in broilers

Avian pathogenic Escherichia coli (APEC) is considered a severe issue to both poultry business and health of the general public. In that context, 50 samples from 250 diseased broiler chickens in 10 chicken farms were employed to Escherichia coli isolation. Microbiological techniques were employed to detect isolates of E. coli from 250 diseased broiler chickens which were examined by antimicrobial susceptibility profiles against 11 antimicrobial agents using disc diffusion technique as well as their biofilm forming capacity were detected. In addition to, study the isolation and purification of phages based on spot technique to verify that lytic phages are present in E. coli isolates and plaque assay for titration of bacteriophages. In the present research, we also looked at the ability of bacteriophages to inhibit and dissolve previously formed biofilms by E. coli O78 isolate. Moreover, experimental testing of E. coli O78 bacteriophages for colibacillosis prevention and control in one day old broiler chicks were done. The obtained results showed that twenty-six E. coli isolates out of 50 examined samples were isolated (10.4%). The most prevalent serotypes were O78, O121:H7, O146:H2, O124, O113:H4, O112:H2, O1:H7, O55:H7, O2:H6, O91:H21, O26:H11. Antibiogram results demonstrated the resistance of E. coli isolates with high percentage 100% were against, Ampicillin, Amoxicillin and Tetracycline. Biofilm quantification analysis showed that 24/26 (92.3%) isolates were considered biofilm producer isolates. The characterization and the lytic activity of bacteriophage were performed based on Transmission electron microscopy and showed the greatest lytic activity against the evaluated host strains with effective activity at concentration of 10⁷ at 24 h and strong significant reduction of the established E. coli O 78 biofilm within 12 h. The result of experimental infection showed that the performance indicators of phage in treated and challenged group showed high significant increase in body weight, weight gain and improved FCR than infected –antibiotic treated and infected bacteriophage and antibiotic treated. Total viable cell counts of E. coli in the lungs of birds revealed that there is highly significant difference between the six groups count results. We concluded that phage therapy found to be an attractive option to prevent and control multidrug resistant colibacillosis in broilers.

Novel mono- and multi-strain probiotics supplementation modulates growth, intestinal microflora composition and haemato-biochemical parameters in broiler chickens

Background

The reduction of antimicrobial usage in food‐producing animals necessitates the intense search for novel alternatives, including new probiotic strains with more effective properties in improving growth performance and curtailing diseases in animals.

Objective

This study evaluated the effects of novel mono‐ and multi‐strain probiotics on the growth performance, intestinal microbiota and haemato‐biochemical parameters of broilers.

Methods

A total of 160 one‐day‐old Cobb 500 broilers were divided into eight treatment groups with two replicates consisting of (1) basal diet (negative control), (2) basal diet with antibiotic, colistin sulphate, (3) basal diet with commercial probiotic, PROMAX® (positive control), (4) basal diet with Pediococcus acidilactici I5, (5) basal diet with P. pentosaceus I13, (6) basal diet with Enterococcus faecium C14, (7) basal diet with Lactobacillus plantarum C16 and (8) basal diet with the combination of all the four probiotic strains. Birds were kept for 35 days and through oral gavage, 1 ml of 108 study probiotic strains administered on days 3–6, 14 and 18.

Results

Supplementation with P. pentosaceus I13, L. plantarum C16 or multi‐strain probiotics significantly (p < 0.05) improved the body weight gain and feed conversion ratio with decrease in feed intake and intestinal Enterobacteria counts. There was a significant (p < 0.05) increase in haemoglobin, mean corpuscular volume, total white blood cells, platelets counts and a lowered (p < 0.05) total cholesterol and glucose levels in multi‐strains probiotic supplemented birds.

Conclusion

The supplementation with novel multi‐strain probiotics improved growth, intestinal health and haemato‐biochemical parameters in broilers and could be used as suitable antibiotic alternatives.

Effects of Bacillus amyloliquefaciens LFB112 on Growth Performance, Carcass Traits, Immune, and Serum Biochemical Response in Broiler Chickens

This study aimed to investigate the effects of Bacillus amyloliquefaciens LFB112 on the growth performance, carcass traits, immune response, and serum biochemical parameters of broiler chickens. A total of 396 1 day old, mixed-sex commercial Ross 308 broilers with similar body weights were allotted into six treatment groups. The assigned groups were the CON group (basal diet with no supplement), AB (antibiotics) group (basal diet + 150 mg of aureomycin/kg), C+M group (basal diet + 5 × 10⁸ CFU/kg B. amyloliquefaciens LFB112 powder with vegetative cells + metabolites), C group (basal diet + 5 × 10⁸ CFU/kg B. amyloliquefaciens LFB112 vegetative cell powder with removed metabolites), M group (basal diet + 5 × 10⁸ CFU/kg B. amyloliquefaciens LFB112 metabolite powder with removed vegetative cells), and CICC group (basal diet + 5 × 10⁸ CFU/kg Bacillus subtilis CICC 20179). Results indicated that chickens in the C+M, C, and M groups had higher body weight (BW) and average daily gain (ADG) (p < 0.05) and lower feed conversion ratio (FCR) (p = 0.02) compared to the CON group. The C+M group showed the lowest abdominal fat rate compared to those in the CON, AB, and CICC groups (p < 0.05). Compared to the CON group, serum IgA and IgG levels in the C+M, C, and M groups significantly increased while declining in the AB group (p < 0.05). B. amyloliquefaciens LFB112 supplementation significantly reduced the serum triglyceride, cholesterol, urea, and creatinine levels, while increasing the serum glucose and total protein (p < 0.05). In conclusion, B. amyloliquefaciens LFB112 significantly improved the growth performance, carcass traits, immunity, and blood chemical indices of broiler chickens and may be used as an efficient broiler feed supplement.

Bacillus subtilis DSM29784 Alleviates Negative Effects on Growth Performance in Broilers by Improving the Intestinal Health Under Necrotic Enteritis Challenge

Along with banning antibiotics, necrotic enteritis (NE), especially subclinical enteritis (SNE), poses a significant threat to the chicken industry; however, probiotics are a potentially promising intervention. We aimed to investigate the beneficial effects of Bacillus subtilis DSM29784 (BS) on the treatment of Clostridium perfringens (CP)-induced SNE in broilers. A total of 360 1-day-old broiler chicks were divided into three treatment groups, namely control (Ctr), SNE, and BS treatment (BST) groups, all of which were fed with a basal died for 21days, and then from day 22 onward, only the BST group had a BS supplemented diet (1×10⁹ colony-forming units BS/kg). On day 15, all chicks, except the Ctr group, were challenged with a 20-fold dose coccidiosis vaccine and 1ml CP (2×10⁸) on days 18–21 for SNE induction. Beneficial effects were observed on growth performance in BST compared to SNE broilers. BST treatment alleviated intestinal lesions and increased the villus height/crypt depth ratio. Further, BST broilers showed increased maltase activity in the duodenum compared with SNE chicks, and a significantly decreased caspase-3 protein expression in the jejunum mucosa. Moreover, an increased abundance of Ruminococcaceae and Bifidobacterium beneficial gut bacteria and an altered gut metabolome were observed. Taken together, we demonstrate that the manipulation of microbial gut composition using probiotics may be a promising prevention strategy for SNE by improving the composition and metabolism of the intestinal microbiota, intestinal structure, and reducing inflammation and apoptosis. Hence, BS potentially has active ingredients that may be used as antibiotic substitutes and effectively reduces the economic losses caused by SNE. The findings of this study provide a scientific foundation for BS application in broiler feed in the future.

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

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

Dietary Probiotic Bacillus licheniformis H2 Enhanced Growth Performance, Morphology of Small Intestine and Liver, and Antioxidant Capacity of Broiler Chickens Against Clostridium perfringens-Induced Subclinical Necrotic Enteritis

The reduction in the use of antibiotics in the poultry industry has considerably increased the appearance of Clostridium perfringens (CP)-induced subclinical necrotic enteritis (SNE), forcing researchers to search alternatives to antibiotic growth promoters (AGP) like probiotics. This study aimed to investigate the effect and the underlying potential mechanism of dietary supplementation of Bacillus licheniformis H2 to prevent SNE. A total of 180 1-day-old male broiler chickens (Ross 308) were randomly divided into three groups, with six replicates in each group and ten broilers per pen: (a) basal diet in negative control group(NC group); (b) basal diet + SNE infection(coccidiosis vaccine + CP) (SNE group); (c) basal diet + SNE infection + H2 pre-treatment(BL group). Growth performance, morphology of small intestine and liver, and antioxidant capacity of the serum, ileum, and liver were assessed in all three groups. The results showed that H2 significantly suppressed (P < 0.05) the negative effects on growth performance induced by SNE, including loss of body weight gain, decrease of feed intake, and raise of feed conversion ratio among the different treatments at 28 days. The addition of H2 also increased (P < 0.05) the villus height: crypt depth ratio as well as villus height in the ileum. Chicks fed with H2 diet had lower malondialdehyde (MDA) concentration in the ileum in BL group than that in SNE group (P < 0.05). Moreover, compared with other treatment groups, dietary H2 improved the activities of antioxidant enzymes in the ileum, serum, and liver (P < 0.05). H2 may also prevent SNE by significantly increasing the protein content (P < 0.05) of Bcl-2 in the liver. Dietary supplementation of H2 could effectively prevent the appearance of CP-induced SNE and improve the growth performance of broiler chickens damaged by SNE, of which the mechanism may be related to intestinal development, antioxidant capacity, and apoptosis which were improved by H2.

Effects of oregano essential oil as an antibiotic growth promoter alternative on growth performance, antioxidant status, and intestinal health of broilers

This experiment was conducted to assess the comparative effects of dietary antibiotics and oregano essential oil (OEO) addition on growth performance, antioxidant status and intestinal health of broilers. A total of 384 one-day-old broilers were randomly allocated to 4 treatments with 6 replicates of 16 broilers each. The 4 treatments were: an antibiotic-free control diet (control), control + 20 mg/kg colistin sulfate and 20 mg/kg virginiamycin (antibiotics), control + 200 mg/kg natural oregano essential oil (NOEO), and control + 200 mg/kg synthetic oregano essential oil (SOEO). The experiment lasted for 42 d. Results showed that birds fed with OEO had greater (P < 0.05) average daily gain (ADG) and lower (P < 0.05) feed conversion ratio (FCR) than those fed with control diet during d 1 to 21. Besides, birds fed with NOEO had the greatest (P < 0.05) ADG in the four groups during d 22 to 42. The serum oxidative stress parameters showed that OEO improved (P < 0.05) the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and glutathione reductase (GR) of birds on day 21 and the activity of total antioxidant capacity (T-AOC) of birds on d 42. Relative to control, NOEO increased (P < 0.05) the activity of T-AOC in jejunum and decreased (P < 0.05) the level of malondialdehyde (MDA) in serum and jejunum. Moreover, OEO supplementation increased (P < 0.05) the concentrations of sIgA in duodenum and jejunum, Lactobacillus and total anaerobes in cecum, as well as activities of trypsin, chymotrypsin, lipase and amylase in duodenum, but restrained (P < 0.05) the amount of Escherichia coli. The NOEO supplementation increased (P < 0.05) total anaerobes of broilers on d 42 and the villus height to crypt depth ratio (VH/CD) of ileum. These results suggest that OEO improved antioxidant status and intestinal health of broilers which contributed to the growth performance improvement of broilers. Dietary OEO supplementation can be a promising alternative to antibiotic growth promoters for improving poultry production.

Probiotics and gut health: linking gut homeostasis and poultry productivity

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

Effects of Clostridium butyricum- and Bacillus spp.-Based Potential Probiotics on the Growth Performance, Intestinal Morphology, Immune Responses, and Caecal Microbiota in Broilers

We aimed to investigate the effects of Clostridium butyricum-, Bacillus subtilis-, and Bacillus licheniformis-based potential probiotics on the growth performance, intestinal morphology, immune responses, and caecal short chain fatty acids (SCFAs) and microbial structure in broiler chickens. Three treatment groups containing a total of 1200 one-day-old AA broilers were included: birds fed with a basal diet only (Con), birds fed with added 10¹⁰ probiotics cfu/kg (ProL), and birds fed with added 10¹¹ probiotics cfu/kg (ProH). The dietary probiotics significantly improved the final and average body weights and serum immunoglobulins A, M, and Y. The probiotics also enhanced the ileal morphology and improved the caecal acetate, butyrate, and propionate contents. Furthermore, 16S rRNA sequencing revealed that dietary compound probiotics modulated the caecal microflora composition as follows: (1) all birds shared 2794 observed taxonomic units; (2) treatment groups were well separated in the PCA and PCoA analysis; (3) the relative abundance of Parabacteroides, Ruminococcaceae_UCG-014, Barnesiella, Odoribacter, [Eubacterium_coprostanoligenes_group], [Ruminococcus]_torques_group, and Butyricimonas significantly varied between treatments. The compound probiotics improved the growth performance, serum immune responses, the ratio of ileal villus height to crypt depth, and major caecal SCFAs in broiler chickens. The dietary C. butyricum-, B. subtilis-, and B. licheniformis-based probiotics improved overall broiler health and would benefit the poultry industry.

Transcriptome Analysis Revealed Ameliorative Effects of Bacillus Based Probiotic on Immunity, Gut Barrier System, and Metabolism of Chicken under an Experimentally Induced Eimeria tenella Infection

In this study, we performed transcriptome analysis in the cecum tissues of negative control untreated non-challenged (NC), positive control untreated challenged (PC), and Bacillus subtilis (B. subtilis) fed challenged chickens (BS + ET) in order to examine the underlying potential therapeutic mechanisms of Bacillus based probiotic feeding under an experimental Eimeria tenella (E. tenella) infection. Our results for clinical parameters showed that birds in probiotic diet decreased the bloody diarrhea scores, oocyst shedding, and lesion scores compared to positive control birds. RNA-sequencing (RNA-seq) analysis revealed that in total, 2509 up-regulated and 2465 down-regulated differentially expressed genes (DEGs) were detected in the PC group versus NC group comparison. In the comparison of BS + ET group versus PC group, a total of 784 up-regulated and 493 down-regulated DEGs were found. Among them, several DEGs encoding proteins involved in immunity, gut barrier integrity, homeostasis, and metabolism were up-regulated by the treatment of probiotic. Functional analysis of DEGs also revealed that some gene ontology (GO) terms related with immunity, metabolism and cellular development were significantly affected by the exposure of probiotic. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that the DEGs in the cecum of B. subtilis-fed challenged group were mainly participated in the pathways related with immunity and gut barrier integrity, included mitogen-activated protein kinase (MAPK) signaling pathway, toll-like receptor (TLR) signaling pathway, extracellular matrix (ECM)–receptor interaction, tight junction, and so on. Taken together, these results suggest that Bacillus based probiotic modulate the immunity, maintain gut homeostasis as well as barrier system and improve chicken metabolism during E. tenella infection.

Bacillus amyloliquefaciens CECT 5940 improves performance and gut function in broilers fed different levels of protein and/or under necrotic enteritis challenge

Two studies were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/-), and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/-). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/-). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels (P < 0.001). Supplementation of BA increased BWG (P < 0.001) and reduced FCR (P = 0.043) across dietary treatments, regardless of challenge. Bacillus (P = 0.030) and Ruminococcus (P = 0.029) genomic DNA copy numbers and concentration of butyrate (P = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG (P = 0.010) and uric acid levels in serum (P < 0.001). Supplementation of BA improved BWG (P = 0.001) and FCR (P = 0.005) and increased Ruminococcus numbers (P = 0.018) and butyrate concentration (P = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced Clostridium perfringens numbers only in birds fed with RCP diets (P = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine (P = 0.013), valine (P = 0.020), and lysine (P = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.

Dietary probiotics as a strategy for improving growth performance, intestinal efficacy, immunity, and antioxidant capacity of white Pekin ducks fed with different levels of CP

The potential impacts of probiotics on the performance and health status of white Pekin ducks fed with optimal or suboptimal dietary CP were evaluated during the growing period. A total of 180 male white Pekin ducks (14-day-old ducks with an initial weight of 415.65 ± 2.20 g) were randomly divided into 4 experimental groups (45 in each group of 5 replicates) in a 2 × 2 factorial design. The main factors included 2 dietary CP levels (18 or 14%) and dietary probiotic addition (with or without probiotics). The probiotic source was supplemented at 0.2 g per kilogram of diet from a blend of Lactobacillus acidophilus and Lactobacillus casei. The results showed that the diet containing 18% CP and probiotics significantly increases the final and total weight gain. Activities of intestinal enzymes (amylase, lipase, and protease), morphometrics (villus length, goblet cell count, and cryptal depth), and carcass percentage were also increased significantly. Total protein content, lysozyme activity, bactericidal activity, nitro blue tetrazolium levels, alternative complement pathway, superoxide dismutase activity, and catalase activity were significantly increased, whereas glucose, cortisol, and total cholesterol levels were decreased when treated with diet containing 18% CP and probiotics. Conversely, the group treated with diet containing 14% CP without probiotics showed the poorest performance, carcass properties, immune response, and antioxidant potential. In conclusion, probiotic addition to the 14% CP diet improved the performance of white Pekin ducks caused by reduced CP diet to performance due to the 18% CP diet without probiotic supplementation.

Comparative Effects of Using New Multi-Strain Synbiotics on Chicken Growth Performance, Hematology, Serum Biochemistry and Immunity

Simple Summary

Currently, there is an urgent need to decrease the use of antibiotics in poultry production. Long-term use of antibiotics in birds leads to the development of many drug-resistant microorganisms, has a negative impact on the environment and the antibiotic residues in poultry meat pose hazards to consumers’ health. Probiotics, prebiotics and synbiotics used in poultry are good alternatives for antibiotic and antibiotic growth stimulants. However, such additives must be adapted to the species, age and intended use of birds. Our newly developed synbiotic formulas which comprised three, four or five strains of Lactobacillus sp., as well as S. cerevisiae and inulin, were administered in feed for meat-type chickens throughout the 42-day experimental period. The results showed that our new synbiotics do not have any unfavorable influence on chicken health and may modulate the immune response and biochemical parameters. The results are very promising, and our synbiotics can be considered as products for commercial use in poultry. However, these findings should be confirmed in future field experiments.

Abstract

In this study, the influence of new multi-strain synbiotics on chicken growth performance, hematology, serum biochemistry and immunity was explored. Each synbiotic preparation (A, B and C) comprised three, four or five strains of Lactobacillus sp., respectively, as well as S. cerevisiae and inulin. All strains used in the synbiotics originated from wild-type strains from animal farms in Poland. Six groups of chickens, ROSS 308 line, were fed with three different synbiotics at a dose of 0.5 g/1 kg of feed. Body weight, as well as the biochemical and hematological parameters of the animals in each study group, were determined on the 7th, 14th, 28th and 42nd day of life. Body weight on day 42 differed between groups and was the highest in control group. This group also had the highestfeed conversion ratio (FCR) value. All measured biochemical parameters were in the normal ranges for poultry; however, we observed a lower alkaline phosphatase (AP) concentration on day 7 in the groups fed with synbiotics, which correlated with a lower level of triglycerides in those groups. The aspartate transaminase (AST) concentration was significantly lower in all groups on day 42 in comparison with the control. On day 7, the control group showed the highest concentration of Ca, K and P. Other parameters did not differ significantly throughout the experiment. All groups showed a similar tendency of increase in the red blood cells (RBC) count according to the age of the birds. Every white blood cells (WBC) population showed differences in the proportions between T and B lymphocytes. The T cell and monocyte counts increased until day 28 in all groups. The results showed that our newly developed synbiotic formulas do not have any unfavorable influence on chicken health and may modulate immune response and biochemical parameters. However, this hypothesis needs to be evaluated in future experiments.

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

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

Evaluation of a Bacillus -Based Direct-Fed Microbial on Aflatoxin B1 Toxic Effects, Performance, Immunologic Status, and Serum Biochemical Parameters in Broiler Chickens

The aim of the present study was to evaluate the effect of a commercial Bacillus direct-fed microbial (DFM) on aflatoxin B1 toxic effects, performance, and biochemical and immunologic parameters in broiler chickens. Ninety 1-day-old Cobb 500 male broiler chicks were raised in floor pens for a period of 21 days. Chicks were neck-tagged, individually weighed, and randomly allocated to one of three groups: Negative control (basal feed), aflatoxin B1 (basal feed + 2 ppm AFB1), and DFM (basal feed + 2 ppm AFB1 + Bacillus direct-fed microbial). Each group had three replicates of 10 chickens (n = 30/group). Body weight and body weight gain were calculated weekly, while feed intake and feed conversion ratio were determined when broilers were 21 days old. On day 21, all chickens were bled, gastrointestinal samples were collected, and spleen and bursa of Fabricius were weighed. This study confirmed that 2 ppm of AFB1 causes severe detrimental effects on performance, biochemical parameters, and immunologic parameters, generating hepatic lesions in broiler chickens (P < 0.05). However, it was also observed that DFM supplementation provided beneficial effects that might help to improve gut barrier function, anti-inflammatory and antioxidant activities, as well as humoral and cellular immunomodulation. The results of the present study suggest that this Bacillus-DFM added at a concentration of 10⁶ spores/gram of feed can be used to counteract the negative effects that occur when birds consume diets contaminated with AFB1, showing beneficial effects on performance parameters, relative organ weights, hepatic lesions, immune response, and serum biochemical variables. The addition of this Bacillus-DFM might mitigate and decrease aflatoxicosis problems in the poultry industry, improving food security, alleviating public health problems, and providing economic benefits. Future studies are needed to fully elucidate the specific mechanisms by which this Bacillus-DFM counteracts the toxic effects of aflatoxin B1.

Composition and inclusion of probiotics in broiler diets alter intestinal permeability and spleen immune cell profiles without negatively affecting performance1

Probiotic feed additives with potential to enhance performance, health, and immunity have gained considerable popularity in commercial broiler production. The study objectives were to measure broiler performance, gut integrity, and splenic immune cell profiles in birds fed one of two probiotics at two inclusion levels. Nine hundred sixty Ross 708 broilers (12 per pen) were randomly assigned to no additive control, 0.05% or 0.10% LactoCare (Lactobacillus reuteri), or 0.05% or 0.10% LactoPlan (Lactobacillus plantarum) dietary treatments for 6 wk. On day 27, a 20-pen subset was utilized for a fluorescein isothiocyanate dextran (FITC-d) assay, where half of the pens were subject to a 12-h feed restriction (FR) pregavage. Serum collected from blood drawn 1-h postgavage was analyzed for relative fluorescence of FITC-d absorbed across the intestinal barrier as a gut leakiness indicator. On day 42, spleens from eight birds per treatment were collected for immune cell profile analysis by multicolor flow cytometry. Although performance outcomes were not affected by dietary treatment, FITC-d absorption post-FR was increased 57% in the 0.05% LactoPlan treatment, and was decreased by 12.6% in the 0.05% LactoCare diet, 12% in the 0.10% LactoCare diet, and 22% in the 0.10% LactoPlan diet compared with the control. This indicates a positive impact in barrier integrity maintenance due to 0.05% and 0.10% LactoCare and 0.10% LactoPlan diet following a challenge. Immune cell profiles varied between the two probiotic compositions, with an approximately 50% reduction in splenic innate immune cells (monocyte/macrophage+) in birds fed LactoPlan (P < 0.0001) and greater overall percentages of CD45+ leukocytes and CD3+ T cells in birds fed 0.10% LactoCare (P < 0.0001). LactoPlan diets shifted splenic T-cell populations in favor of CD8α + cytotoxic T cells (TC; P = 0.007), while higher inclusions (0.10%) of either probiotic increased the percentage of activated CD4+ helper T cells (TH; P < 0.0001). These results indicate that compositionally different probiotics had varying effects on the gut permeability and splenic immune cell profiles in broiler chickens, particularly at higher inclusion rates, but observed changes to underlying physiology did not negatively impact performance outcomes. The ability of a probiotic to alter gut permeability and immune cell profile, therefore, may depend on the compositional complexity of the product as well as inclusion rate.

Effects of the Dietary Probiotic, Enterococcus faecium NCIMB11181, on the Intestinal Barrier and System Immune Status in Escherichia coli O78-Challenged Broiler Chickens

The effects of Enterococcus faecium on growth, intestinal barrier function, and immune response in Escherichia coli O78-challenged broiler chickens were investigated. Three hundred eight 1-day-old Ross male chickens were randomly assigned into three treatment groups: negative control (C), E. coli O78-infected positive (EP), and E. coli O78-infected with 200 mg/kg E. faecium dietary supplementation (EF). E. faecium significantly increased the body weight on day 10 (P < 0.05) and day 15. Furthermore, these birds had a greater average daily gain compared with the other groups during days 1–10 (P < 0.05). The death rate of the EF chickens dramatically declined. E. faecium supplementation improved the jejunal villus height and the ratio of villus height to crypt depth (P < 0.05) 3 and 7 days post-infection. The mRNA expression of claudin-1 significantly increased by E. faecium (P < 0.05) 3 and 7 days post-infection, and Mucin2 was markedly enhanced (P < 0.05) 3 days post-infection. E. faecium upregulated the mRNA expression of PPAR-γ and IL-10 (P < 0.05) and downregulated that of NF-κB, TLR4, and IL-1β (P < 0.05) in the spleen 3 and 7 days post-infection. Lipopolysaccharide stimulation index was markedly enhanced in the EF group (P < 0.05) 3 days post-infection. The increased liver E. coli number caused by the E. coli O78 challenge was significantly reversed by E. faecium (P < 0.05). E. faecium improved growth and reduced the death rate by regulating the immune response and maintaining the intestinal integrity in E. coli O78-challenged broiler chickens.

The association between microbial community and ileal gene expression on intestinal wall thickness alterations in chickens

The dynamic development of the animal intestine with a concurrent succession of microbiota and changes in microbial community and metabolite spectrum can exert far-reaching effects on host physiology. However, the precise mechanism of mutual response between microbiota and the gut is yet to be fully elucidated. Broilers with varying developmental degrees of intestinal wall thickness were selected, and they were divided into the thick group (H type) and the thin group (B type), using multiomics data integration analysis to reveal the fundamental regulatory mechanisms of gut–microbiota interplay. Our data showed, in broilers with similar body weight, the intestinal morphological parameters were improved in H type and the diversity of microbial communities is distinguishable from each other. The beneficial bacteria such as Bifidobacterium breve was increased whereas avian endogenous retrovirus EAV-HP was decreased in the H type compared with the B type. Furthermore, microbial metabolic potentials were more active, especially the biosynthesis of folate was improved in the H type. Similarly, the consolidation of absorption, immunity, metabolism, and development was noticed in the thick group. Correlation analysis indicated that the expression levels of material transport and immunomodulatory-related genes were positively correlated with the relative abundance of several probiotics such as B. breve, Lactobacillus saerimneri, and Butyricicoccus pullicaecorum. Our findings suggest that the chickens with well-developed ileal thickness own exclusive microbial composition and metabolic potential, which is closely related to small intestinal morphogenesis and homeostasis.

Effect of Carotenoids, Oligosaccharides and Anthocyanins on Growth Performance, Immunological Parameters and Intestinal Morphology in Broiler Chickens Challenged with Escherichia coli Lipopolysaccharide

This study was conducted to investigate the effect of carotenoid, oligosaccharide and anthocyanin supplementation in broiler diets under Escherichia coli lipopolysaccharide (LPS) challenge. Ross 308 chickens were fed 5 diets: basal diet (control diet), diet supplemented with β-glucan in 0.05% (positive control) and diets with 0.5% carotenoid-, oligosaccharide- or anthocyanin contents. On the 26th days of age, chickens were challenged intraperitoneally 2 mg LPS per kg of body weight. 12 h after injection, birds were euthanized, then spleen and ileum samples were collected. LPS induced increased relative mRNA expression of splenic (p = 0.0445) and ileal (p = 0.0435) interleukin-1β (IL-1β), which was lower in the spleen in carotenoid (p = 0.0114), oligosaccharide (p = 0.0497) and anthocyanin (p = 0.0303)-treated chickens compared to LPS-injected control birds. Dietary supplementation of carotenoids also decreased relative gene expression of splenic interleukin-6 (IL-6) (p = 0.0325). In the ileum, β-glucan supplementation showed lower relative mRNA expression of toll-like receptor 5 (TLR-5) (p = 0.0387) compared to anthocyanin treatment. Gene expression of both splenic and ileal interferon-α (IFN-α), interferon-γ (IFN-γ), toll-like receptor 4 (TLR-4) and toll-like receptor 5 (TLR-5) were not influenced by dietary supplements. In conclusion, carotenoids, oligosaccharides and anthocyanins could partially mitigate the immune stress caused by LPS challenge. All of the compounds impacted longer villus height (p < 0.0001), villus height:crypt depth ratios were higher after β-glucan (p < 0.0001) and anthocyanin (p = 0.0063) supplementations and thickened mucosa was observed in β-glucan (p < 0.0001), oligosaccharide (p < 0.0001) and anthocyanin (p = 0.048) treatments. All of these findings could represent a more effective absorption of nutrients.

Lactobacillus fermentum Administration Modulates Cytokine Expression and Lymphocyte Subpopulation Levels in Broiler Chickens Challenged with Campylobacter coli

This investigation was performed to assess the supplementation of probiotics on cytokine expression and lymphocyte subpopulation in Campylobacter coli challenged chickens. Thirty-six individuals were equally separated into four experimental treatments: C = untreated chickens, LB = probiotic control (Lactobacillus fermentum), Cc = Campylobacter-challenged control, LBCc = probiotic + Cc. All chicks were slaughtered and cecum samples were collected on day 4 postinfection. Gene expression analysis, using reverse transcription quantitative PCR (RT-qPCR), revealed significant differences in cytokine transcript expression between untreated and probiotic-treated chickens. In addition, flow cytometry was used to quantitate the levels of lymphocyte subpopulations. Principal component analysis showed that probiotic administration induced an overall downregulation of cytokine expression. C. coli exposure provoked a similar response to that of L. fermentum but to a lesser extent. Colonization of C. coli in the presence of the probiotic evoked a complex response with an upregulation of some type II cytokines, including interleukin IL-4 and IL-13, which could explain the increased presence of antibodies in both lamina propria and epithelium. Moreover, despite that the percentage of CD8 intraepithelial lymphocytes (IELs) was found to be higher, downregulation of proinflammatory cytokines IL-15, IL-16, and interferon γ was observed. This suggests that the detected CD8 are not effector cells but induced IELs, which release antimicrobial peptides, and are ready to be primed upon encountering antigen. These outcomes demonstrate that probiotic administration promotes a humoral response to a C. coli infection while dampening any potential inflammation mediated by effector T cells in 1-week-old chicks.

Effects of a combination of xylanase, amylase and protease, and probiotics on major nutrients including amino acids and non-starch polysaccharides utilization in broilers fed different level of fibers

This study evaluated the effects of a combination of xylanase, amylase, and protease (XAP), with probiotics (3 Bacillus spp.) supplementation on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in Cobb 500 broilers from 0 to 21 d. A completely randomized 2 × 4 factorial design (2 levels of fiber; 4 types of supplements) with 8 replicate cages (6 birds/cage) was used. Each low and high-fiber diet contained 500 FTU/kg Buttiauxella sp. phytase and was supplemented with: (a) none (control), (b) XAP (2,000 U xylanase + 200 U amylase + 4,000 U protease/kg diet), (c) probiotics (75,000 CFU/g of Bacillus spp.), or (d) XAP + probiotics. High fiber decreased (P < 0.05) nitrogen-corrected apparent metabolizable energy (AMEn), AID of all amino acids (AA), AID and ATTD of dry matter (DM), crude protein (CP), starch, and gross energy (GE). High fiber increased (P < 0.01) the flow of total non-starch polysaccharides (NSP) in both ileum and total tract. The XAP + probiotics increased (P < 0.01) AMEn as well as AID and ATTD of DM, CP, GE, starch, while alone, XAP yielded similar improvement except for DM compared with control. The supplemental XAP alone improved (P < 0.01) the digestibility of most of the AAs compared with control. Moreover, XAP + probiotics increased (P < 0.05) AID of all AA except arginine and serine compared with control. A fiber × supplements interaction (P < 0.05) was found for AID of histidine and threonine, and their digestibility in high-fiber diet was improved to a level comparable to low-fiber diet by XAP + probiotics. The flow of NSP in XAP group was 5 to 6% lower than in control while NSP flow in XAP + probiotic group was further 4% lower than that of XAP group (P < 0.01). The results infer that the combination of XAP and probiotics can effectively optimize the nutrient digestibility in broilers fed both low and high-fiber diets.

Comparative effects of low zinc oxide dose with or without probiotics relative to high zinc oxide dose on the performance, nutrient digestibility, blood metabolites, and noxious gases emission in weaned piglets

The objective of this study was to assess the effects of low-dose zinc oxide (ZnO) supplemented with or without probiotic complex compared with pharmacological ZnO (3000 mg kg−1) on the performance, digestibility, blood metabolites, fecal Lactobacillus and enterobacteria counts of weaned piglets. One-hundred and twenty crossbred piglets were randomly allocated to three treatments based on their initial body weight (BW). Treatments consisted of corn–soybean-meal-based basal diet supplemented with 3000 mg kg−1 ZnO as positive control (ZH), basal diet supplemented with 300 mg kg−1 ZnO as negative control (ZL), and ZL + 0.1% probiotic complex (ZLP). At the end of the experiment, fecal samples were collected by direct rectal massage to determine nutrient digestibility, Lactobacillus and enterobacteria counts, and gas emission, whereas blood samples were taken via jugular venipuncture for determination of blood metabolites. The BW of piglets at week 6, and the average daily gain (ADG) at week 6 and during overall period were higher (P < 0.05) in pigs fed ZH diet compared with those fed ZL diet. The supplementation of ZLP increased the ADG during week 6 and overall making it comparable with ZH diet (P < 0.05). However, other parameters described above were comparable with ZH in pigs fed ZLP diet.

Dietary hydrolysed yeast cell wall extract is comparable to antibiotics in the control of subclinical necrotic enteritis in broiler chickens

1. The aim of this study was to examine the effect of yeast cell wall (YCW) on performance and physiological responses of broiler chickens under subclinical necrotic enteritis challenge.2. Six treatments in a 2 × 3 factorial arrangement (non-challenged or challenged plus no supplement, YCW or antibiotics (AB)) was used. Each treatment was replicated eight times with 12 birds per replicate. The treatments included: (1) Positive control (PC; no additive, not challenged); (2) Negative control (NC; no additive, with challenge); (3) YCWN = yeast cell wall (2.0 g/kg diet, not challenged; (4) YCWC = yeast cell wall (2.0 g/kg diet, challenged); (5) ABN = zinc bacitracin 50 ppm + Salinomycin 60 ppm, not challenged); (6) ABC = zinc bacitracin 50 ppm + Salinomycin 60 ppm, challenged).3. Eimeria challenge at 9 d of age did not affect feed intake (FI), body weight gain (BWG), FCR or liveability at 10 d. The BWG and FCR at 10 d were greater (P < 0.05) in birds fed YCW or AB (AB) diets relative to the PC or NC groups. On 24 and 35 d, FI, BWG, FCR and flock uniformity (28 d) were greater (P < 0.05) in the challenged groups fed YCW or AB diets compared to NC group.4. Supplementation with YCW ameliorated the negative effects of NE on liver, spleen and bursa weight of birds.5. Necrotic enteritis challenge decreased (P < 0.05) caecal Lactobacillus and Bifidobacterium spp. counts, and increased ileum lesion score and caecal Clostridium perfirngens counts. This was reversed by the addition of either YCW or AB.6. Supplementation with YCW and AB resulted to a greater (P < 0.05) dressing percentage and meat yield (35 d).7. The results indicated that YCW plays a vital role in improving the physiological response and performance of broiler chickens under subclinical necrotic enteritis challenge.