Modulation of chicken gut microbiota for enhanced productivity and health: A review

Microbiota in the digestive tract has become an interesting topic for researchers in recent years. The profile of chicken digestive tract microbiota and its relationship with health and production efficiency have become basic data for modulating the diversity and abundance of the digestive tract microbiota. This article reviews the techniques used to analyze the diversity, role, and function of the gastrointestinal microbiota and the mechanisms by which they are modulated. The gut microbiota plays an important role in animal production, especially during feed digestion and animal health, because it interacts with the host against pathogens. Feed modulation can be a strategy to modulate gut composition and diversity to increase production efficiency by improving growth conditions.

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

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

Effects of Total Sulfur Amino Acids on Growth Performance, Immunity, and Meat Yield in Broilers Fed Diets With and Without Antibiotics

Two experiments were conducted to evaluate the effects of digestible sulfur amino acids (SAA) on performance, carcass yield, immunity, and amino acid transporters in broilers fed diets with or without an antibiotic growth promoter (AGP). In experiment 1, a total of 250 1-day-old Cobb500 male chicks were assigned to battery cages with two levels of AGP (0 and 0.05% bacitracin) and five levels of SAA (0.7, 0.8, 0.9, 1.0, and 1.1%) for 21 d. In experiment 2, a total of 900 1-day-old Cobb500 male chicks were assigned to floor pens with two levels of AGP and three levels of SAA for the starter (0.7, 0.8, and 0.9%) or finisher phase (0.52, 0.62, and 0.72%) for 42 d. In experiment 1, from 0 to 7 d, the body weight gain (BWG) was the lowest for birds fed 0.7% SAA. The AGP significantly decreased the feed conversion ratio (FCR), and birds fed 0.9 and 1.1% SAA had significantly lower FCR than 0.7% SAA. From 8 to 14 d, for the AGP-fed birds, the lowest BWG was observed in the 0.7% SAA group. In birds not fed AGP, birds fed 0.8% SAA had higher BWG than 0.7 and 1.1% SAA. Birds fed 0.7% SAA diet had lower feed intake (FI) than 0.8% SAA and higher FCR than 0.8, 0.9, and 1.0% SAA. In experiment 2, from 0 to 21 d, the lowest BWG and the highest FCR were observed in birds fed 0.7% SAA, whereas birds fed 0.9% SAA had the highest BWG and lowest FCR. From 22 to 42 d, FCR was lower for birds fed AGP, and for birds fed 0.72%. Interactions between the factors were found for FI and BWG. The whole thigh and wing weights were the highest for 0.62% SAA, and the pectoralis major weight was higher for birds fed 0.62% SAA than those fed 0.52% SAA. There was an interaction between SAA and AGP for Lat1 (large neutral amino acid transporter) expression, and AGP-fed birds had higher expression of ileal interleukin 1β (Il−1β gene). The interleukin 10 (Il-10) expression was upregulated in the ileum. There was an interaction between factors for sodium-dependent neutral amino acid transporter B [0] AT1 (SLC6A19) expression. The results suggested that both AGP and SAA supplementation would affect the growth performance of the broilers.

Effects of zinc dosage and particle size on gut morphology, tight junctions and TNF-α expression in broiler breeder hens

This study was performed to evaluate the effects of different amounts and particle size of zinc oxide (ZnO) on villus height (VH), villus width (VW), crypt depth (CD) and VH to CD ratio (VH: CD), and expression of zonula occludens-1 (ZO-1), occludin (OC) and tumour necrosis factor-α (TNF-α) in broiler breeders. A total of 350 (Ross 308) broiler breeder hens of 54 weeks randomly assigned to seven treatments, included control basal diet (C) without added Zn, C+ 100, and 130 mg Zn per kg of diet from Large (L) (100-1000 nm) and Small (S) (<100 nm) particle size ZnO (LZnO100 and 130; SZnO100 and 130), C and SZnO100 challenged with lipopolysaccharide (C+LPS and SZnO100+LPS). Each diet was fed to five replicates consisting of ten birds each. The middle part of the duodenum, jejunum and ileum was used for morphological assessments. To assess the gene expression of ZO-1, OC and TNF-α in the jejunum samples were excised. Results showed that the supplementing 130 ppm SZnO increased VH:CD in the duodenum (p < 0.05). VW in the duodenum and all the evaluated morphometric indices in jejunum and ileum were not affected by the dietary treatment (p > 0.05). ZO-1 mRNA abundance in C+LPS group compared to SZnO100+LPS group was significantly decreased and increased by LPS and SZnO100 respectively. The SZnO-100 increased OC gene expression in compare to C+LPS group. The expression of TNF-α in C+LPS treatment was higher than other groups (p < 0.05). The lowest and the highest litter moisture and foot-pad dermatitis (FPD) were observed in LZnO-130 and C treatments respectively (p < 0.05). Improving the physical properties of ZnO affect on VH:CD. Broiler breeder diet with ZnO enhance ZO-1, OC and mitigate TNF-α gene expression in jejunum maintenance of gut health in broiler breeders.

Duodenal Histomorphological Changes in Broilers Administered poly d, l-lactic-coglycolic acid (PLGA ) Nanoparticles Encapsulated with Peptide

This research was carried out to evaluate the effect of poly d, l-lactic-coglycolic acid(PLGA) nanoparticles loaded with peptide (as vaccine) on histomorphological in duodenum of broiler chick. A total of ninety eight, one day old ,unsexed broiler( Rose) chicks were divided randomly into seven groups( 2 replicate in each group) as follows:G1-control,G2 - chicks received traditional vaccine of infectious bursal disease(Volvac@ IBD MLV) ,G3 – Chicks Received PLGA nanoparticles only, G4,G5,G6 and G7 – chicks were received prepared vaccine at 160, 80, 40,and 20 μg of peptide loaded PLGA respectively. At the end of the experiment histopathological examination of duodenum section and histomorphological changes were examined. The histopathological examination of duodenal sections shows an elongation and infiltration of lamina propria (LP) with increase villi height and crypt depth in groups that received PLGA alone and those received peptide loaded PLGA. At the same time these groups reveal an increase in mucosal thickness and in length and width of villi. The histomorphological examination in this study show thicker mucosal layer with deeper crypt in duodenum of broilers that subjected to PLGA administration alone or to different concentration of peptide loaded PLGA compared to G1 and G2. These findings are accompanied by a high density of goblet cells and lower villus hight/crypt depth (V/CD) ratio. All groups show mononuclear cells (MNCs) infiltration in submucosa ofduodenum. In-conclusion, the administration of PLGA nanoparticles is strongly linked to the improvement of the physiological and immunological features of the birds.

Salmonella Enteritidis reduction in layer ceca with a Bacillus probiotic

BACKGROUND AND AIM

Salmonella Enteritidis (SE) is a significant foodborne pathogen that can often be traced to poultry and poultry products. This study aims to evaluate the ability of three commonly used non-antimicrobial feed additives in reducing the amount of SE in the ceca of laying type pullets.

MATERIALS AND METHODS

On day 0, 60 Hy-Line Brown pullets aged 9 weeks were allocated to individual cages in 15 replicate blocks of four pens. Pullets were administered a mash feed provided ad libitum without supplementation (control) or with dietary supplementation of 454 g/ton yeast cell wall (YCW), or 454 g/ton Bacillus spp. probiotic, or 1133 g/ton yeast culture (YC). On day 3 of the trial, all birds were orally administered 3×107 CFU of a nalidixic acid-resistant SE. On day 10, 7 days after inoculation, all birds were humanely euthanized, and the ceca were aseptically removed for analysis.

RESULTS

There was no significant difference in the prevalence of SE among treatments. The mean quantity of SE detected in the ceca expressed in log10 most probable number/g was 2.52 in the control, 2.49 in the YCW treatment, 1.73 in the probiotic treatment, and 1.66 in the YC treatment. The reduction between control and probiotic and control and YC was significant (p=0.021).

CONCLUSION

This study demonstrates the ability of the novel probiotic and the YC to reduce the load of SE in layer ceca.

Effects of Dietary Direct Fed Microbial Supplementation on Performance, Intestinal Morphology and Immune Response of Broiler Chickens Challenged With Coccidiosis

Poultry coccidiosis is a costly intestinal disease that leads to considerable tissue damage, inefficient nutrient absorption, increased mortality, and predisposition to secondary infections. This study evaluated the effects of a direct feed microbial (DFM) dietary additive on performance, intestinal morphology, and immune response of broilers during a mixed coccidiosis challenge. In total, 840 Cobb500 male broilers were randomly allocated to 3 treatments (7 replicates, 40 birds/pen) including negative control (NC) fed basal diet; positive control (PC) fed basal diet with coccidiosis challenge; and DFM supplemented diet, with coccidiosis challenge. At 15 days of age, all birds except for the NC treatment were orally gavaged with live oocysts of a commercial vaccine. On d 21 (6 days post challenge), 4 birds/pen were randomly selected and euthanized for scoring of coccidia-caused lesions in the duodenum, jejunum, and ceca. Body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were recorded on d 7, 14, 28, and 42. Jejunal and ileal tissue samples were taken for histomorphological assessment from 2 birds/pen on d 21. Ileal samples were also taken for mRNA expression analysis on d 14 and d 21. The DFM birds had significantly greater BWG than PC birds during d 0-21 (P < 0.05). No differences were observed among the treatment groups in terms of FI and FCR. Dietary DFM supplementation significantly reduced lesion scores in the duodenum and jejunum when compared with PC group (P < 0.05). The coccidia challenge significantly reduced (P < 0.05) ileal villus height when compared to the non-challenged group on d 21. Conversely, dietary DFM supplementation alleviated the negative effects of coccidiosis by increasing ileal villus area on d 21 (P < 0.05). The challenged birds had significantly greater expression of IFN-γ and IL-1β in the ileum on d 21. Based on these findings, dietary DFM supplementation may help restore broiler performance during the starter and early grower periods during coccidiosis, likely by maintaining gut integrity via improving intestinal morphology and also by reducing disease severity as manifested by lower lesion scores.

Effect of dietary probiotics on the semen traits and antioxidative activity of male broiler breeders

This study aimed to investigate the effect of probiotics on the intestinal morphology, intestinal microflora, oxidative activity (biological antioxidant potential), and semen quality of male broiler breeders. For this, 180 Cobb male broiler breeders (60 weeks of age) were randomly distributed into two groups. The control group was fed a basal diet, and the probiotics group was fed basal diet supplemented with probiotics for 6 weeks. Probiotics containing Bacillus amyloliquefaciens TOA5001 improved the above mentioned characteristics of the male broiler breeders. Thus, B. amyloliquefaciens TOA5001 might improve the reproductive performance of male broiler breeders.

Performance, gut morphology and microbiology effects of a Bacillus probiotic, avilamycin and their combination in mixed grain broiler diets

1. This study aimed to determine the effect of avilamycin (AGP) and a multi-strain Bacillus probiotic (DFM) on the performance, gut histology and microbiology of broilers fed on a mixed grain diet. 2. A total of 800 chicks were allocated to four treatments: a control diet, control+AGP, control+DFM, or control+AGP+DFM. Bodyweight, feed intake and FCR were measured at d 0, 21 and 42. Samples were taken at d42 to determine villus height (VH), crypt depth (CD) and ratio (VH:CD). Mucosal E. coli and Lactobacilli counts were measured at d42. 3. At d42, DFM and AGP+DFM significantly increased weight over the control, with AGP returning an intermediate value. FCR followed a similar pattern. DFM and AGP+DFM significantly increased VH and CD in all gut sections compared to the control. 4. DFM and AGP+DFM reduced E. coli counts compared to control, with AGP reducing caecal counts only, while Lactobacilli counts were increased. 5. Divergent histology and microbiology between treatments highlight the different modes of action of AGP and DFM for improving broiler growth and feed efficiency.

Vegetative Bacillus amyloliquefaciens cells do not confer protection against necrotic enteritis in broilers despite high antibacterial activity of its supernatant against Clostridium perfringens in vitro

In this study, the effect of Bacillus amyloliquefaciens on Clostridium perfringens was tested in vitro and in vivo. Using an agar well diffusion assay, the inhibitory activity of B. amyloliquefaciens supernatant was analysed against a large collection of netB-positive and netB-negative C. perfringens strains. Although strong growth inhibiting activity was detected against all C. perfringens isolates, it was significantly higher against virulent netB-positive C. perfringens strains compared with avirulent netB-negative isolates. Subsequently, the efficacy of in-feed administration of lyophilised vegetative cells of B. amyloliquefaciens to prevent necrotic enteritis was tested in vivo using an established experimental infection model in broilers. Ross 308 broilers received either B. amyloliquefaciens supplemented or unsupplemented feed throughout the experiment. No significant differences could be detected between the untreated positive control group and the B. amyloliquefaciens treated group in body weight, the number of chickens that developed necrotic lesions and in pathological lesion scores. These results demonstrate that despite its substantial inhibitory activity in vitro, lyophilised vegetative B. amyloliquefaciens cells had no beneficial effect against necrotic enteritis in the in vivo model used here.

Bacillus amyloliquefaciens supplementation alleviates immunological stress in lipopolysaccharide-challenged broilers at early age

This study was conducted to investigate the effect of Bacillus amyloliquefaciens ( BA: ) on the immune function of broilers challenged with lipopolysaccharide ( LPS: ). 192 one-day-old male Arbor Acre broiler chickens were randomly distributed into four treatments: 1) broilers fed a basal diet; 2) broilers fed a basal diet supplemented with BA; 3) LPS-challenged broilers fed a basal diet; and 4) LPS-challenged broilers fed a basal diet supplemented with BA. Each treatment consisted of six replicates with eight broilers per replicate. Broilers were intraperitoneally injected with either 500 μg LPS per kg body weight or sterile saline at 16, 18 and 20 d of age. LPS decreased the average daily gain ( ADG: , P = 0.001) and average daily feed intake (P = 0.001). The decreased ADG (P = 0.009) and increased feed conversion ratio (P = 0.047) in LPS-challenged broilers were alleviated by BA. LPS increased the relative spleen weight (P = 0.001). Relative spleen (P = 0.014) and bursa (P = 0.024) weights in the LPS-challenged broilers were reduced by BA. LPS increased white blood cell ( WBC: ) numbers (P = 0.001). However, the WBC numbers (P = 0.042) and the ratio of lymphocytes to WBC (P = 0.020) in LPS-challenged broilers were decreased with BA treatment. LPS decreased plasma lysozyme activity (P = 0.001), but increased concentrations of plasma corticosterone (P = 0.012) and IL-2 (P = 0.020). In contrast, BA increased lysozyme activity in plasma (P = 0.040). LPS increased mRNA abundances of splenic toll-like receptor 4 (P = 0.046), interferon γ (P = 0.008), IL-1β (P = 0.045) and IL-6, (P = 0.006). IL-2 (P = 0.014) and IL-6 (P = 0.074) mRNA abundances in LPS-challenged broilers were reduced by BA, although BA had an opposite effect for IL-10 mRNA expression in those broilers (P = 0.004). In conclusion, BA supplementation could partially alleviate the compromised growth performance and immune status of broilers under immune stress induced by LPS challenge at early age.