Effect of Direct-fed Microbials on Intestinal Villus Height in Broiler Chickens: A Systematic Review and Meta-Analysis of Controlled Trials

Impact of feed additives and host-related factors on bacterial metabolites, mucosal integrity and immune response in the ileum of broilers

The present study aimed to investigate the effect of age, breed, and sex of broilers, as well as a probiotic or phytobiotic product on mucosal morphology, bacterial metabolites, and immune traits in the ileum of broilers. A total of 2,880 one-day-old male and female broiler chicks from two breeds (Ross308® and Cobb500®) were randomly assigned to 72 pens. Broilers were offered a wheat-soybean diet without (CO), or with either a probiotic (PO; 2.4 × 109 CFU/kg of Bacillus subtilis DSM32324 and DSM32325 and B. amyloliquefaciens DSM25840) or a phytobiotic (PY; grape extract, 165 ppm procyanidin and 585 ppm polyphenols of the diet) product. The trial was conducted with a 3 × 2 × 2 factorial arrangement of diet, breed, and sex in a completely randomized design (6 replicate-pens per treatment). At day 7, 21, and 35, one chicken per pen was slaughtered for collecting ileal tissue to evaluate of histomorphology and mRNA expression, as well as ileal digesta to measure bacterial metabolites. Data were subjected to ANOVA (the main factors; age, diet, breed, and sex) and Four-Way ANOVA (interactions) using GLM procedure. Overall, the concentration of acetate and total short chain fatty acids reached the peak and lactate decreased to its lowest on day 21, but their concentrations at day 7 and 35 were similar (p > 0.05). Spermine, spermidine, and ammonia decreased after day 7, while putrescine and cadaverine increased after day 21 (p < 0.05). mRNA expression of cytokines, mucin 2 (MUC2) and claudin 5 (CLDN5) was similar; increased from day 7 to 21 and decreased afterward (p < 0.05). Villus height, crypt depth and villus surface area increased with age (p < 0.05). Acidic goblet cells (GC) number and density increased after day 21 (p < 0.05). Ross broilers showed higher D-lactate concentration and IFN-γ expression, while Cobb broilers had greater IL-4, IL-6 and TNF-α expression and higher total GC number (p < 0.05). Female displayed higher villus height and GC number and density (mixed and total GC) than male (p < 0.05). The effect of dietary treatment was not found on any investigated variables (p > 0.05). In conclusion, aging of broilers affected ileal histomorphology, cytokine expression, and barrier integrity, as well as bacterial activity. These observed impacts could be attributed to host-microbiota interaction and the direct effects of bacterial metabolites on intestinal cells and immune system.

Effect of Adding Annatto Seed Powder (Bixa orellana) and Astaxanthin to the Diet in the Productive Performance of Broilers(Ross-308)

Researchers from the Al-Anwar Poultry Company conducted the aforementioned study in the Babil Governorate between february 15 and March 22, 2022. The goal of the study was to ascertain the effect of feeding broiler chickens a diet containing annatto seed powder (Bixa orellana) and astaxanthin on their performance and health. The researchers used 225 sexed Ross-308 chickens that were only one day old The chickens were placed in one of 15 different cages, each of which contained one of five different treatments (for a total of 450 birds). There were three duplicates of each treatment, with a total of 15 birds in each replicate for a total of 45 birds in each replication. The following is how the research was conducted: The results showed a highly significant difference at the level of (p 0.01) for the treatments add T2, T3, T4, and T5 regarding final body weight average, with T1 serving as the control treatment and the standard diet not containing any additions. T2 including powdered annatto seeds at a rate of 0.5 grams per kilogram of feed, T3 including powdered annatto seeds at a rate of 1 gram per kilogram of feed, T4 including astaxanthin at At the level of significance (p0.05), Treatments T2, T3, and T5 performed significantly better than the control treatment T1 in terms of the growth in weight, the amount of feed consumed, and the total feed conversion factor.

Effect of dietary supplementation of organic and inorganic Se on performance and antioxidant response in commercial broiler chickens

1. The study was carried out to determine the effects of supplementing organic (OG) or inorganic (IOG) Se to record the performance, immune and anti-oxidant response in broiler chickens.2. One-day-old Vencobb-400 (50.1 ± 0.84 g; n = 280) male broiler chicks were allocated randomly into seven treatments to give eight replicates containing five chicks each and housed in deep littered floor pens (76 cm × 91 cm) for a period of 42 d.3. The control diet (CD) was formulated without any Se supplementation (diet I), CD plus 0.15, 0.30 or 0.45 mg/kg OG Se (diets II, III and IV, respectively) and CD plus 0.15, 0.30 or 0.45 mg/kg IOG Se (diets V, VI and VII, respectively).4. Feed intake (FI), body weight gain (BWG), immune variables and mRNA expression profile of hepatic selenoproteins (SepW, GSHPx1, TrxR and GSHPx3) genes were determined. The BWG, FI and feed conversion ratio did not differ among various dietary treatments.5. The lipid peroxidation and activity of RBC catalase were lower (P < 0.05) in groups fed diets supplemented OG Se compared to those fed IOG Se and CD. The activity of GSH Px was higher among the groups fed diet supplemented OG Se compared to those groups fed OG Se and CD. However, supplementing diets with OG or IOG Se did not affect humoral or cell mediated immune responses.6. The expression levels of SepW were higher (P < 0.01) among the groups supplemented with OG Se. Expression levels of GSH-Px1, TrxR and GSHPx3 were higher (P < 0.01) among the groups supplemented with OG Se compared to those groups fed IOG Se or CD.7. Supplementing OG Se improved the activities of anti-oxidant enzymes and hepatic expression of selenoproteins genes in the present study. However, supplementing OG or IOG Se did not affect growth performance and immune variables in broiler chickens.

Antibiotics in avian care and husbandry-status and alternative antimicrobials

Undoubtedly, the discovery of antibiotics was one of the greatest milestones in the treatment of human and animal diseases. Due to their over-use mainly as antibiotic growth promoters (AGP) in livestock farming, antimicrobial resistance has been reported with increasing intensity, especially in the last decades. In order to reduce the scale of this phenomenon, initially in the Scandinavian countries and then throughout the entire European Union, a total ban on the use of AGP was introduced, moreover, a significant limitation in the use of these feed additives is now observed almost all over the world. The withdrawal of AGP from widespread use has prompted investigators to search for alternative strategies to maintain and stabilize the composition of the gut microbiota. These strategies include substances that are used in an attempt to stimulate the growth and activity of symbiotic bacteria living in the digestive tract of animals, as well as living microorganisms capable of colonizing the host’s gastrointestinal tract, which can positively affect the composition of the intestinal microbiota by exerting a number of pro-health effects, i.e., prebiotics and probiotics, respectively. In this review we also focused on plants/herbs derived products that are collectively known as phytobiotic.

Comparative effect of potentiated zinc oxide and antibiotic growth promoters on intestinal morphometry and nutrient digestibility in broiler chickens

The comparative effects of potentiated zinc oxide (pZnO) and antibiotic growth promoters (AGP) supplementation on intestinal morphometry and nutrient digestibility in broiler chickens were studied. Four hundred straight-run Cobb 500-day-old broiler chicks were randomly allotted to four dietary treatments replicated 10 times with 10 birds per replicate. Dietary treatments were as follows: T1: basal diets without AGP (negative control; NC), T2: basal diets with 500 g/t maduramicin 10 g and 500 g/t zinc bacitracin 150 (positive control; PC), T3: NC added with 150 g/t pZnO, and T4: PC added with 150 g/t pZnO in a 2 × 2 factorial design in RCBD. At days 18 and 35, 10 birds were randomly selected per treatment for morphometry of the duodenum, jejunum, and ileum. At day 38, eight birds per treatment were used for the nutrient digestibility study. Results showed significant interaction effects (P < 0.05) of AGP and pZnO supplementation on day 35 intestinal morphometry of duodenum's villi height and villi height: crypt depth, and ileum's crypt depth; apparent COD_GE, AME, CP, DM, and EE. Significant differences (P < 0.05) with pZnO supplementation were only observed on feed intake and FCR of birds fed with pZnO at days 8-14 and fecal quality at days 0-7. Results of present study suggested that pZnO has the potential to replace AGPs without negatively affecting the intestinal morphometry, digestibility, and growth performance of broiler chickens.

The combination of quillaja and yucca saponins in broilers: effects on performance, nutrient digestibility and ileal morphometrics

1. Two series of studies were conducted to determine the effects of a combination of ground plant material derived from Quillaja saponaria trees and Yucca schidigera plants (QY) as sources of saponin, on performance, productivity, nutrient digestibility and ileal morphology of growing broilers. In each trial, 480 Cobb male birds were allocated equally to 24 pens at one-day-of-age according to body weight2. The studies consisted of two identical floor pen trials in which performance and nutrient digestibility were assessed and two trials where performance and ileal morphology were determined. In each trial, 0, 250 or 500 ppm QY were included in feed given to the broilers from 1-35 or 1-42 d of age, respectively. Eight (digestibility) or 12 (morphology) randomised replicate pens were used.3. In the digestibility trials, two birds per pen were moved to metabolism cages at d 21. Excreta was collected for a five-day period (d 21 to 25) for the determination of apparent total tract digestibility of dry and organic matter, fat and ash and nitrogen retention. For intestinal morphology, ileal segments were collected from four birds/pen on d 21 to determine villus height and crypt depth. Performance data were collected in each trial series.4. Results showed that feeding graded levels of QY produced significant linear improvements in performance and productivity at d 35, and similar linear effects were observed for N retention and all apparent digestibility measurements. Morphology data showed that birds receiving 250 and 500 ppm QY had significantly increased villus height5. These results indicated that QY exerted a positive influence on the intestinal tract by increasing the absorptive surface and improving nutrient digestibility. These effects were considered to be associated with the performance improvements recorded in both experiments.

Comparison of intestinal permeability, morphology, and ileal microbial communities of commercial hens housed in conventional cages and cage-free housing systems

The gastrointestinal health of poultry can be impacted by a variety of factors including their environment. As egg production moves from conventional cage housing (CC) toward cage-free housing (CF), it is important to understand this impact on intestinal health. This study was conducted to determine if housing type impacted intestinal permeability, morphology, and microbial communities in commercial hens across housing systems. Hens were randomly selected from 2 rooms of CC (n = 25) and CF (n = 25) at a commercial facility. Birds were given fluorescein isothiocyanate dextran (FITC-D) by oral gavage to measure intestinal permeability. Jejunal and ileal samples were collected to evaluate villus height, crypt depth, and their ratio. Ileal contents were collected for bacterial DNA isolation and 16S rRNA gene sequencing. Serum FITC-D was similar between housing type (P = 0.709). Hens housed in the CF had increased jejunal villus height and crypt depth compared with hens from the CC (P < 0.002). Hens from the CC tended to have a greater villus height to crypt depth ratio in both the jejunum and ileum compared with the CF (P = 0.064; P = 0.091, respectively). Microbial community diversity measurements favored hens housed in the CC as ileal contents tended to have increased species richness (P = 0.059), had greater alpha diversity (P = 0.044), and had an increased number of over represented operational taxonomic units (46/64), including Romboutsia sp. (30.80%), Lactobacillus kitasatonis (17.16%), and Lactobacillus aviarius (11.15%). Correlations between microbial communities with intestinal traits identified significant association with the greatest number of correlations with FITC-D and ileal morphology. Many of these correlations identified microbial communities associated with expected traits; thus, providing limited functional data to microbial communities with limited information. The greater number of correlations of ileal morphology with ileal microbial communities suggesting local microbial communities contribute to the intestinal environment distant. In this limited study, several parameters favored hens from CC suggesting an advantage of this system for intestinal health. However, the lower intestinal health parameters observed in CF were not at levels to indicate detrimental effects.

Bacillus subtilis delivery route: effect on growth performance, intestinal morphology, cecal short-chain fatty acid concentration, and cecal microbiota in broiler chickens

As the poultry industry recedes from the use of antibiotic growth promoters, the need to evaluate the efficacy of possible alternatives and the delivery method that maximizes their effectiveness arises. This study aimed at expounding knowledge on the effect of the delivery method of a probiotic product (Bacillus subtilis fermentation extract) on performance and gut parameters in broiler chickens. A total of 450 fertile eggs sourced from Cobb 500 broiler breeders were randomly allotted to 3 groups: in ovo probiotic (n = 66), in ovo saline (n = 66), and noninjection (n = 200) and incubated for 21 d. On day 18.5 of incubation, 200 μL of either probiotic (10 × 10⁶ cfu) or saline was injected into the amnion. At hatch, chicks were reallotted to 6 new treatment groups: in ovo probiotic, in ovo saline, in-feed antibiotics, in-water probiotic, in-feed probiotics, and control (corn-wheat-soybean diet) in 6 replicate cages and raised for 28 d. Of all hatch parameters evaluated, only percentage pipped eggs was found significant (P < 0.05) with the noninjection group having higher percentage pipped eggs than the other groups. Treatments did not affect the incidence of necrotic enteritis on day 28 (P > 0.05). Irrespective of the delivery method, the probiotic treatments had no significant effect on growth performance. The ileum villus width of the in ovo probiotic treatment was 18% higher than the in ovo saline group (P = 0.05) but not statistically higher than other groups. The jejunum villus height was 23% higher (P = 0.000) in the in ovo probiotic group than in the control group. There was no effect of treatment on total cecal short-chain fatty acid concentration and cecal gut microbiota composition and diversity (P > 0.05), although few unique bacteria differential abundance were recorded per treatment. Conclusively, although probiotic treatments (irrespective of the delivery route) did not affect growth performance, in ovo delivery of the probiotic product enhanced intestinal morphology, without compromising hatch performance and gut homeostasis.

Could probiotics be the panacea alternative to the use of antimicrobials in livestock diets?

Probiotics are most frequently derived from the natural microbiota of healthy animals. These bacteria and their metabolic products are viewed as nutritional tools for promoting animal health and productivity, disease prevention and therapy, and food safety in an era defined by increasingly widespread antimicrobial resistance in bacterial pathogens. In contemporary livestock production, antimicrobial usage is indispensable for animal welfare, and employed to enhance growth and feed efficiency. Given the importance of antimicrobials in both human and veterinary medicine, their effective replacement with direct-fed microbials or probiotics could help reduce antimicrobial use, perhaps restoring or extending the usefulness of these precious drugs against serious infections. Thus, probiotic research in livestock is rapidly evolving, aspiring to produce local and systemic health benefits on par with antimicrobials. Although many studies have clearly demonstrated the potential of probiotics to positively affect animal health and inhibit pathogens, experimental evidence suggests that probiotics' successes are modest, conditional, strain-dependent, and transient. Here, we explore current understanding, trends, and emerging applications of probiotic research and usage in major livestock species, and highlight successes in animal health and performance.

Performance, Histology, and Meat Quality of Coccidiosis-Challenged Broilers Fed Essential Oils

An experiment was conducted to determine the effects of Ralco’s Microfused Essential Oils (MEO) on growth, jejunal histology, and meat quality of coccidiosis-challenged broilers. Day old broilers (n = 768; 64 pens; 12 broilers/pen) were randomly allotted to 1 of 5 dietary treatments fed in 4 phases: starter (d0–16), grower (d17–27), finisher (d28–34), and withdrawal (d35–41). Diets were a corn-soybean meal basal diet (CON), CON+BMD50/Coban90 at 55/121, 250/550, 250/495 and 0 mg/kg (ANTI), CON+MEO at 375, 250, 125, and 100 mg/kg (MEOD), CON+MEO at constant 500 mg/kg (MEO500), and CON+MEO at constant 250 mg/kg (MEO250). Broilers were offered a 10X dose of a coccidiosis vaccine on d 3, 15, 22, and 29. On d 14, jejunal histology was measured. Two broilers per pen were harvested on d 41 and breast pH was measured. Rancidity compounds (TBARS) were measured on whole breasts at d 7 postmortem and ground thighs on d 0, 3, 5, and 7 postmortem. Overall, MEO250-fed broilers had a tendency for greater gain over CON-fed (63.6 vs. 61.3 ± 0.87 g; P < 0.08). MEOD-fed broilers tended to have greater villus height compared to MEO500-fed (806.6 vs. 716.3 ± 27.7 μm; P = 0.09. No differences were observed for pH or TBARS of breasts (P > 0.05). There were differences in L*, a*, and b* color values of breasts and there was an interaction for color values of thighs. ANTI, MEO500, and MEO250 had decreased TBARS values for thighs compared to CON at d 7 postmortem (P ≤ 0.05). Overall, growth performance of MEO250 was not different than ANTI during peak challenge (P > 0.05). MEO250 could improve growth performance and meat quality when broilers are subjected to a coccidiosis disease challenge.