Effect of Organic Acids in Drinking Water for Young Broilers on Campylobacter Infection, Volatile Fatty Acid Production, Gut Microflora and Histological Cell Changes

Modulation of Performance, Plasma Constituents, Small Intestinal Morphology, and Cecum Microbiota in Growing Geese by Dietary Citric Acid Supplementation

To investigate the efficiency and optimum inclusion level of CA in growing geese diets on performance, plasma constituents, and intestinal health, 240 healthy female geese at the age of 28d were randomly allotted six treatment diets incorporated with 0, 0.8, 1.6, 2.4, 3.2, and 4% CA. Each treatment group consisted of five replicates and eight birds per replicate. The findings demonstrated that 3.2% CA supplementation resulted in improved growth performance (ADG, ADFI, and FBW) (p = 0.001), and geese who received CA also showed lower body fat contents (p < 0.05) than the control group. Moreover, geese from the 2.4% and 3.2% CA group had the highest plasma glutathione peroxidase and insulin-like growth factor 1 levels compared to the other groups (p < 0.05). A microbial diversity analysis of the cecum conducted by 16S rDNA sequencing revealed that 3.2% CA supplementation showed a significantly higher abundance of beneficial bacteria (Muribaculaceae, CHKCI001, Erysipelotricha-ceae_UCG_003, and UCG_009) (p < 0.05) and a lower abundance of harmful bacteria (Atopobiaceae, Streptococcus, Acinetobacter, Pseudomonas, and Alistipes) (p < 0.10). Collectively, our results revealed that dietary supplementation with 3.2% CA had several benefits on the performance and physiological health of growing geese by promoting nutrients metabolism, improving antioxidant capacity, and modulating cecum microbiota.

The antioxidative influence of dietary creatine monohydrate and L-carnitine on laying performance, egg quality, ileal microbiota, blood biochemistry, and redox status of stressed laying quails

The experiment was implemented to assess the influence of dietary supplementation of laying quails with creatine monohydrate (CrM), L-carnitine (CAR) and their mixture (CrMCAR) as antioxidants against oxidative stress (OS) induced by 2.5 ppm lead acetate (LA) in drinking water on productive, physiological and microbial aspects. In total, 400 laying quail females at 10 wk of age were divided into a randomized design with 5 groups and 4 replicates of 20 birds each. Birds were fed ad libitum with a balanced diet for 8 wk. The control group was kept under no-stress conditions and was given fresh water without any additives (G1). While birds in other groups were exposed to OS induced experimentally by 2.5 ppm LA in drinking water with no feed additive (G2) or supplemented with 500 mg/kg CrM (G3) or 500 mg/kg CAR (G4) or combination of 250 mg/kg each of CrM and CAR (CrMCAR, G5) to feed mixture. Compared to G2, G5 demonstrated the reduction (P ≤ 0.05) of feed conversion ratio, feed intake, mortality and ileal total coliform, as well as serum and egg malondialdehyde and serum lipid hydroperoxide, uric acid, glucose, cholesterol, enzymatic activities (alanine aminotransferase, aspartate transaminase, alkaline phosphatase, creatine phosphokinase, γ-glutamyl transferase), and heterophils/lymphocytes ratio. In the meanwhile, there was an increase (P ≤ 0.05) in egg production, egg mass, and weight with the improvement of egg quality, serum sex hormones level and ileal lactic acid bacteria for G5 followed by G4 and G3. Moreover, G5 enhanced (P ≤ 0.05), the total antioxidant capacity of egg and serum glutathione, superoxide dismutase, catalase, glutathione peroxidase, protein and calcium levels. Therefore, dietary CrMCAR, CAR and CrM have analogous influence to control by improving the antioxidant and physiological parameters which resulted in better productive performance and egg characteristics of stressed quails. These antioxidants, especially in their equal combination, are beneficial to alleviate oxidative stress incidence and can be recommended for poultry feeding under various aspects of environmental stresses.

Effects of citric acid supplementation on growth performance, intestinal morphology and microbiota, and blood parameters of geese from 1 to 28 days of age

This study was conducted to investigate the effects of citric acid (CA) supplementation on growth performance, intestinal morphology, intestinal microbiota, and blood parameters of geese from 1 to 28 d of age and evaluate the optimum additional level of citric acid. A total of 180 one-day-old male goslings were randomly allotted to 5 treatment groups of 36 birds with 6 replications. The control group was fed a basal diet, and the other groups were fed the basal diet supplemented with 0.25, 0.50, 1.00, and 2.00% of citric acid, respectively. The results showed that goslings fed the diet supplemented with 1.00% CA had higher final body weight (FBW) and average daily gain (ADG) than other groups (P < 0.05). The CA supplementation at 0.25 to 1.00% improved the morphology of duodenum or jejunum (P < 0.05). The jejunal content pH value was significantly reduced with the addition of CA compared with the control group (P < 0.05). As citric acid levels increased, the IgA concentrations in plasma increased and then decreased, and the goslings fed 1.00% CA supplementation had the highest IgA concentrations (P < 0.05). The supplementation of 1.00% and 2.00% CA in diet significantly reduced the malondialdehyde (MDA) concentration in plasma (P < 0.05). No significant difference was found on some indices related to liver function in plasma (P > 0.05), while creatinine significantly increased by the 2.00% CA supplementation (P < 0.05). Besides, the higher Coliform level in cecal content and worse intestinal morphology were observed when CA supplementation was up to 2.00%. Hence, the dietary CA supplementation (especially 1.00%) in goslings improves the growth performance, intestinal morphology, immunity and antioxidant, while excessive CA addition may cause negative effects. According to the quadratic polynomial model, the addition of CA in diet for obtaining maximum average daily feed intake (ADFI) should be 1.09% (10.9 g/kg diet) for goslings from 1 to 28 d of age.

Dietary coated essential oil and organic acid mixture supplementation improves health of broilers infected with avian pathogenic Escherichia coli

Colibacillosis caused by avian pathogenic Escherichia coli (APEC) is a very prevalent disease in poultry farms in China. The exploration of effective non-antibiotic substances is of great significance for the control of APEC infections. This experiment evaluated the efficacy of coated essential oil and organic acid (EOA) supplementation to prevent E. coli O78 infection in broiler chickens. A total of 288 one-day-old male broiler chicks were randomly distributed into 4 groups with 6 replicates per group. Chickens were fed a diet either supplemented with EOA (500 mg/kg feed) or not, and either uninfected or infected with E. coli O78 intratracheally. Results showed that E. coli O78 infection reduced body weight gain, increased mortality and the ratio of feed to gain along with cecal and liver E. coli load, damaged gut mucosa, induced local and systemic inflammation, and altered cecal microbial composition, diversity and function (P < 0.05). Supplemental EOA improved feed conversion efficiency, lowered gross lesion scores and cecal E. coli population, enhanced intestinal goblet cells and serum IgG concentration, and tended to decrease serum IL-12 production (P < 0.05). Essential oil and organic acid addition downregulated IFN-γ mRNA, tended to decrease mucin-2 mRNA levels while upregulating IL-10 mRNA, and tended to increase ZO-1 gene expression in the jejuna of infected birds at 7 d after E. coli O78 challenge (P < 0.05). The 16S rRNA gene sequencing indicated that both EOA addition and E. coli O78 challenge altered the diversity and composition of the cecal microbiota community. Furthermore, infected birds fed EOA showed decreased Bacteroidetes and genus Lactobacillus abundance compared with the infected control. LEfSe analysis showed that Firmicutes, Ruminococcaceae, Clostridiales, Clostridia, Lactobacillus, Lactobacilaceae, and cc-115 were enriched in the non-infected but EOA-treated group (P < 0.05). Collectively, dietary EOA supplementation could mildly alleviate E. coli-induced gut injury and inflammation.

Systematic review of products with potential application for use in the control of Campylobacter spp. in organic and free-range broilers

Campylobacter spp. are some of the most important food-borne zoonoses in Europe and broiler meat is considered the main source of Campylobacter infections. Organic and free-range broilers have access to outdoor reservoirs of Campylobacter and are more frequently infected at slaughter than the conventional broiler flocks. Limitations to biosecurity and treatment options in these production types calls for additional solutions. This review examines intervention methods with sufficient strength and quality, which are able to reduce the load of Campylobacter safely and efficiently and discuss their applicability in organic and free-range broiler production. Four different products passed the inclusion criteria and their quality examined: ferric tyrosine chelate, a prebiotic fermentation product of Saccharomyces cerevisiae, short-chain fatty acid butyrate coated on microbeads added to feed, and a mix of organic acids added to the drinking water. Though potential candidates for reducing Campylobacter in broilers were identified, there is a lack of large scale intervention studies that demonstrate an effect under field conditions of a free-range broiler production.

Polyphenolic phytochemicals as natural feed additives to control bacterial pathogens in the chicken gut

Poultry provides an important protein source consumed globally by human population, and simultaneously, acts as a substantial reservoir of antibiotic resistant bacterial species such as Escherichia coli, Salmonella, Campylobacter, Clostridium perfringens. These bacterial species can include commensal strains with beneficial roles on poultry health and productivity, and pathogenic strains not only to poultry but zoonotically to man. This review paper evaluates the role of phytochemicals as possible alternatives to antibiotics and natural anti-bacterial agents to control antibiotic resistance in poultry. The focus of this paper is on the polyphenolic phytochemicals as they constitute the major group; carvacrol oil (the active ingredient of oregano), thymol oil (the main ingredient of oregano), oregano oil, and tannins oil as feed additives and their mechanism of actions that might enhance avian gut health by controlling antibiotic-resistant bacterial strains spread in poultry.

Determination of bacterial abundance and communities in the nipple drinking system of cascading cage layer houses

Water quality is critical for egg production and animal health in commercial layer housing systems. To investigate microbial contamination in nipple drinking system in layer houses, the bacterial abundance and communities in water pipes and V-troughs on different tiers (e.g., 1st, 3rd, 5th, and 7th tiers) of a layer house with 8 overlapping cage tiers were determined using qRT-PCR and 16S rRNA sequencing. The water bacterial abundance (i.e., genome 16S rDNA copy number, WBCN) in water pipes and V-troughs did not significantly differ among tiers, but they were 46.77 to 1905.46 times higher in V-troughs than that in water pipes (P < 0.05) for each tier. Illumina sequencing obtained 1,746,303 effective reads from 24 water samples in V-troughs of 4 tiers (six samples from each tier). Taxonomic analysis indicated that the 1st and 5th tiers were predominated by Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes, while the 3rd and 7th tiers were predominated by Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria. The top four genera were Acinetobacter, Streptococcus, Rothia and Comamonas among measured tiers. The high bacterial abundance and bacterial OTUs of water in the V-troughs reflect poor water quality, which may adversely affect growth and health of laying hens. Therefore, it is suggested that water quality in the V-tough should be checked more frequently in commercial layer houses.

Feeding Malic Acid to Chickens at Slaughter Age Improves Microbial Safety with Regard to Campylobacter

Simple Summary

Chicken meat has become a popular food that is consumed worldwide. However, chicken flocks suffer from Campylobacter infection during their rearing period. Campylobacter is the most serious pathogen colonizing chicken flocks which could be transmitted through the food chain and threaten public health. The traditional strategy of using antibiotics to inhibit pathogens in chicken flocks is no longer acceptable due to the increasing risk of antibiotic resistance. Thus, finding alternative antimicrobial agents has become a priority in recent years. In this study, malic acid was supplied to flocks in order to find an effective means of reducing the contamination of Campylobacter and to evaluate its potential effects on poultry production. By using malic acid-supplemented drinking water for 5 days before slaughtering, the Campylobacter carriage was significantly decreased in the treated group compared to the control group. Malic acid has no adverse effects on chickens, though it could change the composition of chicken meat by increasing the moisture content and decreasing the fat content and it could be applied as a potential antimicrobial agent in poultry production.

Abstract

This study supplied malic acid-supplemented drinking water to flocks that were naturally Campylobacter-positive and assessed the effect of feeding malic acid to chickens on Campylobacter reduction and poultry production. In Experiment 1, chickens were provided with malic acid-supplemented drinking water for three weeks. The contamination loads of Campylobacter were decreased by 0.91–0.98 log after the first week of use (p < 0.05). However, this effect did not persist over time and significant decontamination could not be found in the second and third weeks of application. Thus, in Experiment 2 malic acid-supplemented drinking water was given to chickens for a period of five days at slaughter age. The Campylobacter carriage was found to be effectively decreased by 1.05–1.55 log (p < 0.05). Malic acid had no adverse effects on chicken body weight, weight gain, intestinal indices, or the microbiota. In addition, it could change the composition of chicken meat since the moisture content was increased by 5.12–5.92% (p < 0.05) and the fat content was decreased by 1.60% (p < 0.05). Our study provides an effective means for reducing the contamination of Campylobacter during the chicken rearing period and this method can be applied to promote the safe development of poultry farming and its products.

Optimization of the In Vitro Bactericidal Effect of a Mixture of Chlorine and Sodium Gallate against Campylobacter spp. and Arcobacter butzleri

ABSTRACT

Campylobacter spp. and Arcobacter butzleri are foodborne pathogens associated with the consumption of contaminated raw chicken meat. At the industry level, the combination of new and common antimicrobials could be used as a strategy to control the presence of pathogens in chicken carcasses. The objective of this study was to determine the bacteriostatic and bactericidal effects of a mixture of chlorine (Cl) and sodium gallate (SG) on a mixture of two Campylobacter species (Campylobacter jejuni and Campylobacter coli) and A. butzleri. Using a central composite experimental design, it was established that the optimum inhibitory SG-Cl concentration for Campylobacter spp. was 44 to 45 ppm. After 15 h of incubation, Campylobacter species growth was reduced by 37.5% and the effect of Cl was potentiated by SG at concentrations above 45 ppm. In the case of A. butzleri, optimum levels of 28 and 41 ppm were observed for SG and Cl, respectively; no synergism was reported, as this bacterium was more sensitive to lower Cl concentrations than Campylobacter. After a 20-min pretreatment with peracetic acid (50 ppm), the optimum condition to achieve a >1.0-Log CFU/mL reduction of Campylobacter spp. was exposure to 177 ppm of Cl and 44 ppm of SG for 56 min. As A. butzleri showed lower resistance to the bacteriostatic effect of the Cl-SG combination, it was assumed that optimum bactericidal conditions for Campylobacter spp. were effective to control the former; this was confirmed with subsequent validation of the model. The SG-Cl combination has bactericidal properties against Campylobacter and A. butzleri, and it may be a useful strategy to improve sanitary practices applied in the poultry industry.

HIGHLIGHTS

Effect of Replacing In-Feed Antibiotics with Synergistic Organic Acids, with or without Trace Mineral and/or Water Acidification, on Growth Performance and Health of Broiler Chickens Under a Clostridium perfringens Type A Challenge

This study investigated the effects of a proprietary commercial feed additive (FA) comprised of a blend of fatty acids, organic acids, and phytochemicals; a hydroxychloride copper (MA); as well as a water acidification product (WA), alone and in combination, on growth performance in nonvaccinated broiler chickens raised in an antibiotic-free production system. The test treatments were FA; WA; FA and WA combined (FA + WA); and FA, WA, and MA combined (FA + WA + MA). The efficacy of these treatments was compared with a negative control (CON) and a medicated feeding program (bacitracin, antibiotic growth promoter [AGP]). Ross 708 cockerels (n = 2376) were subject to a 3-phase commercial feeding program, namely, starter (0-20 days), grower (21-28 days), and finisher (28-35 days), with no coccidiostats or additional medications added to the feed. On day 14, birds were subjected to an in-feed Clostridium perfringens challenge and a subset of animals were euthanized and the ileal digesta was collected for C. perfringens enumeration. Prior to pathogen challenge (day 14), birds fed the FA + WA and F + WA + MA treatments had significantly higher body weights (+2.6%-3.5%) than those fed CON and similar body weights to birds fed the AGP. These early growth advantages were not sustained postchallenge. Clostridia counts in ileal digesta were dramatically reduced in birds fed the AGP compared with all treatments. The FA (-2.5 log), FA + WA (-2.0 log), and FA + WA + MA (-2.3 log) treatments had significantly lower clostridia counts than the CON treatment. Together, these findings support the use of combined in-feed and in-water strategies for reducing clostridia, while maintaining growth, in antibiotic-free production systems.

Effect of Acetic Acid and Sodium Bicarbonate Supplemented to Drinking Water on Water Quality, Growth Performance, Organ Weights, Cecal Traits and Hematological Parameters of Young Broilers

To evaluate the effect of acetic acid and sodium bicarbonate supplemented to drinking water on water quality, growth performance, relative organ weights, cecal traits and hematological parameters of broilers, a total of 456 one-day-old Cobb MV × Cobb 500 FF mixed broilers were randomly placed in three experimental treatments, with four replicates per treatment and 38 birds per replicate, for 10 days. The treatments consisted of the use of acetic acid (0.4%; T1) as acidifier, an apparently neutral pH (T2) and sodium bicarbonate (1%; T3) as alkalizer of the drinking water. T3 showed the highest values (p < 0.05) for total dissolved solids, electrical conductivity, salinity and pH. T1 and T2 showed the same productive response (p > 0.05); however, T3 decreased (p < 0.05) body weight, feed intake and the relative weight of the pancreas and immune organs and increased (p < 0.05) water intake, mortality and relative weight of the heart and liver. Likewise, T3 increased (p < 0.05) the cecal pH, although without changes for the cecal lactic cecal bacteria count and blood parameters (p > 0.05). The acid pH of the drinking water had no effect on the biological response of broilers compared to T2; however, the T3 provoked high mortality, ascites, low productivity and abnormal growth of some organs.

Growth performance, intestinal histomorphology, gut microflora and ghrelin gene expression analysis of broiler by supplementing natural growth promoters: A nutrigenomics approach

In an epoch of escalating number of antibiotic-resistance bacteria, there is a dire need to develop efficient and novel feeding strategies for animal nutrition as alternatives to antibiotics. Here, implicating nutrigenomic approach, phytobiotics and organic acids were used to evaluate ghrelin gene expression levels, gut microflora composition, performance parameters and intestinal histomorphological changes in broiler chickens. One-day-old chicks (n = 315) were reared for 42 days and distributed randomly into five experimental groups; each with three replicates (21 birds per replicate). Experimental groups were control: basal diet only, antimicrobial growth promoter: 40 g/metric ton of basal diet (virginiamycin), organic acids: 4 kg/metric ton of basal diet, phytobiotics: 3 kg/metric ton of basal diet, combination: 7 kg/metric ton of basal diet (organic acids 4 kg and phytobiotics 3 kg metric ton of feed). Growth performance, histological and ghrelin gene expression analysis were executed on 21 and 42 days while, quantitative bacterial analysis of cecum and ileum was performed on day 42. Increased feed intake and body weight (p < 0.05) were noticed in phytobiotics group. Addition of phytobiotics significantly improved (p < 0.05) villus height and ratio of villus height/crypt depth in ileum, jejunum, and duodenum and down-regulated ghrelin gene expression levels. Total coliform and Escherichia coli in cecal and ileal digesta were decreased significantly (p < 0.05) in organic acids group. Correlation analysis revealed Lactobacillus spp. were positively correlated to villus height/crypt depth ration in duodenum. The findings indicated the importance of gene-nutrient-microbiota interactions based on nutrigenomics approach. Hence, phytobiotics and organic acids might be suitable alternatives to antibiotics for improved performance and immunity, along with healthier meat production in poultry.

The Effect of Acidifier-Dextrose against Hen Day Production and Feed Conversion Ratio in Laying Hens Infected with Avian Pathogenic Escherichia coli

Colibacillosis in Indonesia until now still appears frequently, so the case of colibacillosis laying hens cannot reach the peak of egg production; the egg production period is delayed and easily infected with other diseases. The purpose of this research is that the acidifier-dextrose combination is expected to be able to suppress the development of Avian Pathogenic Escherichia coli (APEC) bacteria in laying hens so that, in the end, the case of colibacillosis can be controlled in Indonesia. A total of 240 heads of laying hens were divided into 6 treatments and each consisted of 40 replications. The results of this research state that a combination of acidifier-dextrose can increase Hen Day Production (p < 0.05) and decrease Feed Conversion Ratio (p < 0.05) in laying hens infected with APEC. The Hen Day Production results of the treatment group infected with APEC showed the lowest results, amounting to 65.75% whereas the other treatments are still above 90%. Furthermore, the highest Feed Conversion Ratio results were on treatments infected with APEC, which amounted to 2.17 while other treatments of the Feed Conversion Ratio results are still below 1.80. In general, the use of a combination of acidifier and dextrose with the lowest dose, that is, 1 g/3.75 liters of drinking water can still give good results to Hen Day Production and Feed Conversion Ratio for laying hens infected with APEC. Giving combination of acidifier-dextrose can increase Hen Day Production and decrease Feed Conversion Ratio in laying hens infected with APEC. The recommended dosage of acidifier-dextrose combination in laying hens based on this research is 1 g/3.75 liters of drinking water.

Sustainable Antibiotic-Free Broiler Meat Production: Current Trends, Challenges, and Possibilities in a Developing Country Perspective

Simple Summary

Chickens are raised with the assistance of the regular use of antibiotics, not only for the prevention and treatment of diseases but, also, for body growth. Overuse and misuse of antibiotics in animals are contributing to the rising threat of antibiotic resistance. Therefore, antibiotic-free broiler meat production is becoming increasingly popular worldwide to meet consumer demand. However, numerous challenges need to be overcome in producing antibiotic-free broiler meat by adopting suitable strategies regarding food safety and chicken welfare issues. This review focuses on the current scenario of antibiotic use, prospects, and challenges in sustainable antibiotic-free broiler meat production. We also discuss the needs and challenges of antibiotic alternatives and provide a future perspective on antibiotic-free broiler meat production.

Abstract

Antibiotic-free broiler meat production is becoming increasingly popular worldwide due to consumer perception that it is superior to conventional broiler meat. Globally, broiler farming impacts the income generation of low-income households, helping to alleviate poverty and secure food in the countryside and in semi-municipal societies. For decades, antibiotics have been utilized in the poultry industry to prevent and treat diseases and promote growth. This practice contributes to the development of drug-resistant bacteria in livestock, including poultry, and humans through the food chain, posing a global public health threat. Additionally, consumer demand for antibiotic-free broiler meat is increasing. However, there are many challenges that need to be overcome by adopting suitable strategies to produce antibiotic-free broiler meat with regards to food safety and chicken welfare issues. Herein, we focus on the importance and current scenario of antibiotic use, prospects, and challenges in the production of sustainable antibiotic-free broiler meat, emphasizing broiler farming in the context of Bangladesh. Moreover, we also discuss the need for and challenges of antibiotic alternatives and provide a future outlook for antibiotic-free broiler meat production.

On farm interventions to minimise Campylobacter spp. contamination in chicken

1. This review explores current and proposed on-farm interventions and assess the potential of these interventions against Campylobacter spp. 2. Interventions such as vaccination, feed/water-additives and, most importantly, consistent biosecurity, exhibit potential for the effective control of this pathogen and its dissemination within the food chain. 3. Due to the extensive diversity in the Campylobacter spp. genome and surface-expressed proteins, vaccination of poultry is not yet regarded as a completely effective strategy. 4. The acidification of drinking water through the addition of organic acids has been reported to decrease the risk of Campylobacter spp. colonisation in broiler flocks. Whilst this treatment alone will not completely protect birds, use of water acidification in combination with in-feed measures to further reduce the level of Campylobacter spp. colonisation in poultry may be an option meriting further exploration. 5. The use of varied types of feed supplements to reduce the intestinal population and shedding rate of Campylobacter spp. in poultry is an area of growing interest in the poultry industry. Such supplements include pro - and pre-biotics, organic acids, bacteriocins and bacteriophage, which may be added to feed and water. 6. From the literature, it is clear that a distinct, albeit not unexpected, difference between the performance of in-feed interventions exists when examined in vitro compared to those determined in in vivo studies. It is much more likely that pooling some of the discussed approaches in the in-feed tool kit will provide an answer. 7. Whilst on-farm biosecurity is essential to maintain a healthy flock and reduce disease transmission, even the most stringent biosecurity measures may not have sufficient, consistent and predictable effects in controlling Campylobacter spp. Furthermore, the combination of varied dietary approaches and improved biosecurity measures may synergistically improve control.

The Current Status of the Alternative Use to Antibiotics in Poultry Production: An African Perspective

Over the years the growth and health of food-producing animals have been enhanced by the use of antibiotics. These have helped reduce on-farm mortalities, lower incidences of diseases and more importantly improve productivity. Generally, the utilization of antibiotics in feed has been reevaluated since bacterial pathogens have established and shared a variety of antibiotic resistance mechanisms that can easily be spread within microbial communities. Multiple countries have introduced bans or severe restrictions on the non-therapeutic use of antibiotics. This has therefore warranted the urgent need for alternatives. Africa is facing its own challenges as it has been reported to be one of the continents with the highest number of foodborne diseases with approximately 91 million related diseases and 137,000 death per annum. Stakeholder and policy direction has been put in place to curb this escalation; however, the problem persists. The use of alternatives has been recommended and some successfully used in other countries as well as Africa, including pro- and prebiotics and phytochemicals. This then leads to the core aim of this review which is to (1) determine the extent to which antimicrobial-resistant pathogens have affected Africa, (2) assess the current measures put in place by Africa to reduces antimicrobial resistance and finally (3) explore the alternative use of antibiotics in poultry production. Improved sanitary conditions and farm biosecurity are important alternatives that could be adopted by farmers instead of depending on antibiotic drugs for disease control and prevention.

Effects of in ovo injection of prebiotics and synbiotics on the productive performance and microstructural features of the superficial pectoral muscle in broiler chickens

The aim of the study was to compare the effects of 2 prebiotics and 2 synbiotics injected in ovo on productivity parameters, quality, and microstructure of the superficial pectoral muscle in 35-day-old broiler chickens. On day 12 of incubation, 9,000 eggs Ross 308 were randomly divided into 5 experimental groups treated with different bioactives in ovo injected: C, control with physiological saline; PI, with 1.760 mg inulin; PB, with 0.528 mg of commercial prebiotic Bi2tos; SI, with 1.760 mg inulin and 1,000 CFU Lactococcus lactis spp. lactis IBB SL1; SB, with 0.528 mg Bi2tos and 1,000 CFU Lactococcus lactis spp. cremoris IBB SC1. The synbiotic solution contained 20 μl bacterial suspension and 180 μl prebiotic solution. For productive parameters and further tests ten male birds for each experimental group were used. The birds were slaughtered on day 35 of age. At slaughter, samples of the left pectoral muscles were taken and preserved by freezing in liquid nitrogen. The pH and color of the meat were evaluated at 45 min and 24 h post-mortem. Water holding capacity (WHC) was measured and expressed as the percentage of free water in meat. Microscopic specimens were analysed using MultiScan software for the measurement of the percentage of oxidative and glycolytic fibres and mean diameter of the muscle fibres. In ovo injection of prebiotics Bi2tos had a positive effect on body weight. In prebiotic group (PI) a negative impact on hatchability was observed. Prebiotics and synbiotics had no influence on the yield of the carcass and pectoral muscle. Bioactive compounds had a significant effect on the quality of meat parameters such as: pH 24 h (PI and PB group), L* 45' (SI and SB group), and WHC (groups PB, SI, and SB). The analysis of the enzymatic profile showed a significant increase in the percentage of glycolytic fibres in the pectoral muscle from chicken treated with a synbiotic with the addition of inulin (group SI).

Effect of a high dose of exogenous phytase and supplementary myo-inositol on mineral solubility of broiler digesta and diets subjected to in vitro digestion assay

This study was conducted to evaluate the effect of microbial phytase and myo-inositol supplementation in low non-phytate phosphorus (nPP) diets on pH and the solubility of minerals in an in vitro digestion procedure (IVDP) and to compare this with digesta from birds fed different diets (grower diets) compared to the in vitro test (starter diets). A total of 660 1-day-old broilers were randomly allotted into 11 dietary treatments and fed a corn-soybean-meal-based diet with recommended nPP (positive control; PC), an nPP-deficient diet (negative control; NC), NC diets supplemented with phytase (500; 1,000; 2,000; 3,000; 4,000; 5,000; and 6,000 FTU/kg), an NC diet plus 0.15% myo-inositol, and an NC diet with reduced Ca level (Ca: nPP ratio same as PC) from 1 to 23 D of age. The pH and Ca solubility of the NC diet was increased compared with the PC when subjected to IVDP (P < 0.05). P solubility in the gizzard and jejunal digesta was reduced in the NC compared with the PC diet and this was also reflected in the IVDP. Phytase addition to the NC diets linearly increased (P < 0.05) the pH value and Ca and P solubilities in both digesta and diets subjected to IVDP. Higher doses of microbial phytase increased (P < 0.05) Zn and Fe solubilities in both digesta and IVDP. Myo-inositol supplementation of the NC diet had no effect on mineral solubility, but decreased (P < 0.05) the pH of the IVDP. Lowering the Ca content of the NC diet decreased (P < 0.05) the pH of the in vitro digested diets and Ca solubility in both broiler digesta and IVDP and also increased (P < 0.05) P solubility in both the jejunal digesta and IVDP. Correlations were noted between the solubility of P in the in vitro assay and that in the gizzard and jejunal digesta, and also with bird performance, confirms the usefulness of in vitro assay.

Growth performance and gastrointestinal responses in heavy Tom turkeys fed antibiotic free corn-soybean meal diets supplemented with multiple doses of a single strain Bacillus subtilis probiotic (DSM29784)1

Growth performance and gastrointestinal (GIT) responses to a single-strain of Bacillus subtilis (SSB) were investigated using 960 Hybrid Converter Toms. A total of 4 iso-caloric and iso-nitrogenous corn-soybean meal-based diets were allocated to 12 replicate cages/pens and fed (ad libitum) in a four-phase feeding program (starter; days 0 to 28, grower-1; days 29 to 56, grower-2; days 57 to 84, and finisher; days 85 to 126). The diets had either 0 (control), 1E+08 (low), 2E+08 (mid) or 1E+09 (high) cfu B. subtilis/kg. Feed intake (FI) and BW were recorded by phase. Excreta samples were collected towards the end of starter and grower-1 phases for apparent retention (AR) of components by marker method and litter moisture, respectively. Selected birds were necropsied on days 28 and 56 for GIT weight and samples for jejunal histomorphology and ceca digesta short chain fatty acids (SCFA). Supplemental SSB had linear and non-linear (P < 0.05) response on BW gain (BWG). Specifically, relative to the control, birds fed low SSB had higher BWG in starter and grower-1 phases whereas bird fed mid and high SSB had lower BWG in grower-2 and birds fed low and mid SSB had higher BWG in finisher phase. Consequently, birds fed low and mid SSB doses were heavier (P < 0.05) than control fed birds at the end of trial. The FCR response to SSB was linear and non-linear (P < 0.05) with birds fed low SSB showing lower FCR than control fed birds in starter, grower-1 and finisher phases. Supplemental SSB had linear and non-linear (P < 0.05) effects on AR of components (DM, ash, crude protein, crude fat, neutral detergent fiber, and gross energy), litter moisture, GIT weight, jejunal histomorphology, and SCFA. Relative to control, birds fed high SSB showed higher AR of components, villi height, day 56 ceca digesta total SCFA concentration, and lower litter moisture. In conclusions, under condition of the current study, growth performance was optimized by low to mid SSB. Improved nutrient retention and indices of gut health suggested higher SSB doses may optimize growth performance under challenging farm conditions.

Inhibition and Interactions of Campylobacter jejuni from Broiler Chicken Houses with Organic Acids

Campylobacter jejuni is a bacterium that causes major diarrheal disease worldwide and is also one of the top five foodborne pathogens encountered in the United States. Poultry is a major source of C. jejuni, and a high-risk factor for contracting campylobacteriosis. Organic acids are used in the United States during food animal processing for removal of bacterial contamination from animal carcasses. Six organic acids were evaluated in inhibition studies of 96 C. jejuni strains obtained from shoe covers used in broiler chicken houses at different poultry farms in several states by determining the susceptibilities of the C. jejuni strains, along with the pH values at the molar minimum inhibitory concentrations (MICMs). The undissociated and dissociated organic acid concentrations were calculated at the MICMs with the Henderson-Hasselbalch equation. The results for the 96 C. jejuni strains were treated similarly for each different organic acid. Campylobacter jejuni inhibition did correlate with the dissociated organic acids, but did not correlate with pH or with the undissociated organic acids. When the concentrations of dissociated organic acids decreased, the C. jejuni strains were not disinfected. A carcass wash using organic acids should have the concentration of dissociated acid species carefully controlled. It is suggested to maintain a dissociated acid concentration for propionic, l-lactic, formic, citric, butyric, and acetic acids at 24, 40, 36, 21, 23, and 25 mM, respectively, and at these dissociated organic acid levels an acid wash would be expected to remove or inhibit 97% or more of the C. jejuni bacteria studied here. However, studies must be undertaken to confirm that the suggested concentrations of dissociated organic acids are adequate to remove C. jejuni bacteria in the field vs. the laboratory. Due to propionate, l-lactate, formate, butyrate, and acetate being utilized by C. jejuni, these organic acids may not be appropriate for use as a carcass wash to remove C. jejuni surface contamination. Of all tested organic acids, dissociated citric acid was the most efficient at inhibiting C. jejuni.

The role of whey on the performance and campylobacteriosis in broiler chicks

The objective of the present study was to investigate the effect of the whey on broiler chicks' performance, welfare, and caecal Campylobacter counts under experimental and field conditions. In the experimental study, 120-d-old broiler chicks were randomly allocated to four treatment groups, as described below: group A, which served as negative control; group B, fed with a diet supplemented with 1% whey; group C, challenged with Campylobacter jejuni; and group D, supplemented with 1% whey and challenged with C. jejuni, respectively. Performance indexes and caecal C. jejuni counts were calculated. In addition to the performance indexes, the hock burn and the foot pad dermatitis lesions score were measured to assess the welfare status of broiler chicks. In order to evaluate the use of whey under field conditions, a second study was performed in a broiler farm with two identical houses. The evaluation of the experimental data revealed that the use of whey did not affect significantly the performance (P ≤ 0.05) and the caecal C. jejuni counts (P ≤ 0.05). There were neither footpad dermatitis lesions nor hock burn lesions in any of the experimental groups. In the field study, the use of whey had no effect on the performance indexes (P ≤ 0.05). It can be concluded that the addition of whey has no negative effect on poultry and may provide an alternative natural feed additive for the broiler feed industry.

Influence of acidified drinking water on growth performance and gastrointestinal function of broilers

The ban on the use of antibiotic feed additives as growth promoters compelled the researchers for exploring the future utility of other alternatives. This experiment was designed to evaluate the effect of acidified drinking water on growth performance, gastrointestinal pH, digestive enzymes, intestinal histomorphology, and cecum microbial counting of the broiler chicken. A total of 540 one-day-old male broilers (Arbor Acre) were randomly assigned to 5 treatments, with 6 replicates of 18 chicks per replicate. Broilers received diets and water as follows: NC (negative control, basal diet, normal water), PC (positive control, basal diet + 8 ppm colistin sulfate + 8 ppm enduracidin, normal water), A1 (basal diet, continuous supply of acidified water during whole experiment period), A2 (basal diet, intermittent acidification of water during 0 to 14 d, 22 to 28 d, and 36 to 42 d), and A3 [basal diet, intermittent acidification of water (24 h/d from 0 to 14 d and from 10:00 am to 4:00 pm on d 15 to 42)]. During the entire period, the acidified groups (A1, A2, and A3) and PC group showed improve on weight gain, average daily gain and feed conversion ratio compared to NC group (P < 0.05). The pH in crop, proventriculus and ileum at 43 d declined by 0.04, 1.03, 1.23; 0.55, 0.69, 0.70; and 0.63, 0.74, 1.21 in A1, A2, and A3 group, respectively. There was a significant decline of lipase activity in the PC and acidified groups compared to NC group. The A2 group had higher villus height in jejunum than NC group. The PC and acidified groups reduced (P < 0.05) the total aerobic bacteria count of cecum when contrasted to NC group. Therefore, we conclude that acidified drinking water can improve growth performance, compensate for gastric acidity, and control pathogenic bacteria in broilers and may be considered as a potential alternative to improve production parameters. Discontinuous supply of acidified water had the same or even better influence on broilers compared to continuous supply.

Use of antibiotics in broiler production: Global impacts and alternatives

Antibiotics are used to fight bacterial infections. However, a selective pressure gave rise to bacteria resistant to antibiotics. This leaves scientists worried about the danger to human and animal health. Some strategies can be borrowed to reduce the use of antibiotics in chicken farms. Much research has been carried out to look for natural agents with similar beneficial effects of growth promoters. The aim of these alternatives is to maintain a low mortality rate, a good level of animal yield while preserving environment and consumer health. Among these, the most popular are probiotics, prebiotics, enzymes, organic acids, immunostimulants, bacteriocins, bacteriophages, phytogenic feed additives, phytoncides, nanoparticles and essential oils.

Cleaning and disinfection programs against Campylobacter jejuni for broiler chickens: productive performance, microbiological assessment and characterization

Detailed cleaning and disinfection programs aims to reduce infection pressure from microorganisms from one flock to the next. However, studies evaluating the benefits to poultry performance, the sanitary status of the facilities, and the sanitary quality of the meat are rarely found. Thus, this study was designed to evaluate 2 cleaning and disinfecting programs regarding their influence on productive performance, elimination of Campylobacter, and characterization of Campylobacter jejuni strains when applied to broiler chickens’ facilities. Two subsequent flocks with 960 birds each were distributed into 32 pens containing 30 birds each. In the first, the whole flock was inoculated with a known strain of Campylobacter jejuni in order to contaminate the environment. In the second flock, performance and microbiological evaluations were done, characterizing an observational study between 2 cleaning and disinfection programs, regular and proposed. The regular program consisted of sweeping facilities, washing equipment and environment with water and neutral detergent. The proposed cleaning program consisted of dry and wet cleaning, application of 2 detergents (one acid and one basic) and 2 disinfectants (250 g/L glutaraldehyde and 185 g/L formaldehyde at 0.5% and 210 g/L para-chloro-meta-cresol at 4%). Total microorganism count in the environment and Campylobacter spp. identification were done for the microbiological assessment of the environment and carcasses. The positive samples were submitted to molecular identification of Campylobacter spp. and posterior genetic sequencing of the species identified as Campylobacter jejuni. The birds housed in the facilities and submitted to the proposed treatment had better performance when compared to the ones in the regular treatment, most likely because there was a smaller total microorganism count on the floor, walls, feeders and drinkers. The proposed program also resulted in a reduction of Campylobacter spp. on floors, drinkers and birds. Moreover, it was possible to identify 6 different Campylobacter jejuni strains in the facilities. The proposed treatment resulted in a positive influence on the birds’ performance and reduction of environment contamination for broiler chickens.

Bacillus spp. as direct-fed microbial antibiotic alternatives to enhance growth, immunity, and gut health in poultry

The increasing occurrence of antibiotic-resistant bacteria combined with regulatory pressure and consumer demands for foods produced without antibiotics has caused the agricultural industry to restrict its practice of using antibiotic growth promoters (AGP) in food animals. The poultry industry is not immune to this trend, and has been actively seeking natural alternatives to AGP that will improve the health and growth performance of commercial poultry flocks. Bacillus probiotics have been gaining in popularity in recent years as an AGP alternative because of their health-promoting benefits and ability to survive the harsh manufacturing conditions of chicken feed production. This review provides an overview of several modes of action of some Bacillus direct-fed microbials as probiotics. Among the benefits of these direct-fed microbials are their production of naturally synthesized antimicrobial peptides, gut flora modulation to promote beneficial microbiota along the gastrointestinal tract, and various immunological and gut morphological alterations. The modes of action for increased performance are not well defined, and growth promotion is not equal across all Bacillus species or within strains. Appropriate screening and characterization of Bacillus isolates prior to commercialization are necessary to maximize poultry growth to meet the ultimate goal of eliminating AGP usage in animal husbandry.

TYPLEX® Chelate, a novel feed additive, inhibits Campylobacter jejuni biofilm formation and cecal colonization in broiler chickens

Reducing Campylobacter spp. carriage in poultry is challenging, but essential to control this major cause of human bacterial gastroenteritis worldwide. Although much is known about the mechanisms and route of Campylobacter spp. colonization in poultry, the literature is scarce on antibiotic-free solutions to combat Campylobacter spp. colonization in poultry. In vitro and in vivo studies were conducted to investigate the role of TYPLEX® Chelate (ferric tyrosine), a novel feed additive, in inhibiting Campylobacter jejuni (C. jejuni) biofilm formation and reducing C. jejuni and Escherichia coli (E. coli) colonization in broiler chickens at market age. In an in vitro study, the inhibitory effect on C. jejuni biofilm formation using a plastic bead assay was investigated. The results demonstrated that TYPLEX® Chelate significantly reduces biofilm formation. In an in vivo study, 800 broilers (one d old) were randomly allocated to 4 dietary treatments in a randomized block design, each having 10 replicate pens with 20 birds per pen. At d 21, all birds were challenged with C. jejuni via seeded litter. At d 42, cecal samples were collected and tested for volatile fatty acid (VFA) concentrations and C. jejuni and E. coli counts. The results showed that TYPLEX® Chelate reduced the carriage of C. jejuni and E. coli in poultry by 2 and 1 log10 per gram cecal sample, respectively, and increased cecal VFA concentrations. These findings support TYPLEX® Chelate as a novel non-antibiotic feed additive that may help produce poultry with a lower public health risk of Campylobacteriosis.

Influence of dietary carbohydrases, individually or in combination with phytase or an acidifier, on performance, gut morphology and microbial population in broiler chickens fed a wheat-based diet

The objective of this study was to examine the effects of dietary carbohydrases (xylanase and β-glucanase; XG), individually or in combination with phytase or acidifier on the growth performance, carcass attributes, intestinal microbial counts and morphology in broiler chickens fed a wheat-based diet. A total of 240 one-day-old male broiler chicks were randomly allocated into 4 treatment groups with 6 replicates of 10 birds each. The dietary treatments included a basal diet, the basal diet with an enzyme complex containing XG, XG plus a microbial phytase (XG + P) and XG plus acidifier (XG + A). The results indicated that feed conversion ratio (FCR) was improved in broiler chickens which received XG + A during the entire production period (1 to 35 d) of the trial (P < 0.05). The broiler chickens fed XG + P had lower feed intake compared with the control group at 29 to 35 d of age. The experimental treatments had no effect on the body weight gain of broiler chickens. In carcass traits, except for spleen (P < 0.05), the dietary treatments had no effects on the carcass characteristics of broiler chickens. The birds which received diets supplemented with XG and XG + A had a lower weight of the spleen compare with the control. Addition of XG in combination with phytase (XG + P) resulted in a decrease in ileal enumeration of Escherichia coli at 35 d of age (P < 0.05). However, dietary treatments did not alter the population of ileal Lactobacilli in broiler chickens. Supplementing carbohydrases with phytase and acidifier (XG + P and XG + A) significantly increased the intestinal villus length at 35 d of age (P < 0.05). In conclusion, the present study demonstrated that supplementation of the wheat-based diet with a combination with carbohydrases and acidifier (XG + A) improves FCR in broiler chickens. Furthermore, combinations of carbohydrases with phytase (XG + P) and with acidifier (XG + A) decrease the E. coli counts and increase the villus length in broiler chickens.

Coadministration of the Campylobacter jejuni N-Glycan-Based Vaccine with Probiotics Improves Vaccine Performance in Broiler Chickens

Source attribution studies report that the consumption of contaminated poultry is the primary source for acquiring human campylobacteriosis. Oral administration of an engineered Escherichia coli strain expressing the Campylobacter jejuni N-glycan reduces bacterial colonization in specific-pathogen-free leghorn chickens, but only a fraction of birds respond to vaccination. Optimization of the vaccine for commercial broiler chickens has great potential to prevent the entry of the pathogen into the food chain. Here, we tested the same vaccination approach in broiler chickens and observed similar efficacies in pathogen load reduction, stimulation of the host IgY response, the lack of C. jejuni resistance development, uniformity in microbial gut composition, and the bimodal response to treatment. Gut microbiota analysis of leghorn and broiler vaccine responders identified one member of Clostridiales cluster XIVa, Anaerosporobacter mobilis, that was significantly more abundant in responder birds. In broiler chickens, coadministration of the live vaccine with A. mobilis or Lactobacillus reuteri, a commonly used probiotic, resulted in increased vaccine efficacy, antibody responses, and weight gain. To investigate whether the responder-nonresponder effect was due to the selection of a C. jejuni "supercolonizer mutant" with altered phase-variable genes, we analyzed all poly(G)-containing loci of the input strain compared to nonresponder colony isolates and found no evidence of phase state selection. However, untargeted nuclear magnetic resonance (NMR)-based metabolomics identified a potential biomarker negatively correlated with C. jejuni colonization levels that is possibly linked to increased microbial diversity in this subgroup. The comprehensive methods used to examine the bimodality of the vaccine response provide several opportunities to improve the C. jejuni vaccine and the efficacy of any vaccination strategy.IMPORTANCE Campylobacter jejuni is a common cause of human diarrheal disease worldwide and is listed by the World Health Organization as a high-priority pathogen. C. jejuni infection typically occurs through the ingestion of contaminated chicken meat, so many efforts are targeted at reducing C. jejuni levels at the source. We previously developed a vaccine that reduces C. jejuni levels in egg-laying chickens. In this study, we improved vaccine performance in meat birds by supplementing the vaccine with probiotics. In addition, we demonstrated that C. jejuni colonization levels in chickens are negatively correlated with the abundance of clostridia, another group of common gut microbes. We describe new methods for vaccine optimization that will assist in improving the C. jejuni vaccine and other vaccines under development.

Competitive Exclusion Reduces Transmission and Excretion of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Broilers

Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases (pAmpC) are enzymes able to hydrolyze a large variety of β-lactam antibiotics, including third-generation cephalosporins and monobactams. Broilers and broiler meat products can be highly contaminated with ESBL- and pAmpC-producing Escherichia coli strains, also known as extended-spectrum cephalosporin (ESC)-resistant E. coli strains, and can be a source for human infections. As few data on interventions to reduce the presence of ESC-resistant E. coli in broilers are available, we used transmission experiments to examine the role of competitive exclusion (CE) on reducing transmission and excretion in broilers. A broiler model to study the transmission of ESC-resistant E. coli was set up. Day-old chickens were challenged with an ESBL-producing E. coli strain isolated from healthy broilers in the Netherlands. Challenged and not challenged chicks were housed together in pairs or in groups, and ESBL-producing E. coli transmission was monitored via selective culturing of cloacal swab specimens. We observed a statistically significant reduction in both the transmission and excretion of ESBL-producing E. coli in chicks treated with the probiotic flora before E. coli challenge compared to the transmission and excretion in untreated controls. In conclusion, our results support the use of competitive exclusion as an intervention strategy to control ESC-resistant E. coli in the field.IMPORTANCE Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases are a primary cause of resistance to β-lactam antibiotics among members of the family Enterobacteriaceae in humans, animals, and the environment. Food-producing animals are not exempt from this, with a high prevalence being seen in broilers, and there is evidence pointing to a possible foodborne source for human contamination. We investigated the effect of administration of a commercial probiotic product as an intervention to reduce the amount of ESBL-producing Escherichia coli in broilers. Our results showed a substantial reduction in the level of colonization of broiler intestines by ESBL-producing E. coli after administration of commercial probiotic product. The protective effect provided by these probiotics could be implemented on a larger scale in poultry production. Reductions in the levels of ESBL-producing Enterobacteriaceae in the food chain would considerably benefit public health.

The influence of feeding crimped kernel maize silage on growth performance and intestinal colonization with Campylobacter jejuni of broilers

An infection trial and a production trial over 35 days were conducted in parallel to study the influence of feeding crimped kernel maize silage (CKMS) on the intestinal Campylobacter jejuni colonization and broiler performance, respectively. The CKMS was used at dietary inclusion levels of 15% and 30% in maize-based diets. Broilers were orally inoculated with 2 × 10(5) log cfu/ml C. jejuni on day 14. Four birds from each pen were randomly selected and killed by cervical dislocation on days 3, 6, 9, 14 and 21 post infection and intestinal contents from ileum, caeca and rectum as well as liver samples were taken. Body weight and feed consumption of broilers were registered on days 13, 22 and 35. On day 35, litter dry matter (DM) was measured and the condition of the foot pads was evaluated. There was no significant effect of CKMS on the colonization of C. jejuni. Body weight of the broilers supplemented with 15% CKMS was comparable with the control maize-based feed, whereas addition of 30% CKMS reduced broiler body weight (P < 0.001). However, DM intake and feed conversion ratio were the same in all three dietary treatments. Furthermore, the foot pad condition of broilers significantly improved with the inclusion of CKMS on broiler diets as a result of a higher DM content in the litter material. It is concluded that CKMS did not influence intestinal Campylobacter colonization, but improved the foot pad health of broilers.

Campylobacter in Poultry: Ecology and Potential Interventions

Avian hosts constitute a natural reservoir for thermophilic Campylobacter species, primarily Campylobacter jejuni and Campylobacter coli, and poultry flocks are frequently colonized in the intestinal tract with high numbers of the organisms. Prevalence rates in poultry, especially in slaughter-age broiler flocks, could reach as high as 100% on some farms. Despite the extensive colonization, Campylobacter is essentially a commensal in birds, although limited evidence has implicated the organism as a poultry pathogen. Although Campylobacter is insignificant for poultry health, it is a leading cause of food-borne gastroenteritis in humans worldwide, and contaminated poultry meat is recognized as the main source for human exposure. Therefore, considerable research efforts have been devoted to the development of interventions to diminish Campylobacter contamination in poultry, with the intention to reduce the burden of food-borne illnesses. During the past decade, significant advance has been made in understanding Campylobacter in poultry. This review summarizes the current knowledge with an emphasis on ecology, antibiotic resistance, and potential pre- and postharvest interventions.

Impact of a drug-free program on broiler chicken growth performances, gut health, Clostridium perfringens and Campylobacter jejuni occurrences at the farm level

The use of antimicrobial agents as feed additives in poultry production is a public health concern due to the overall increase in antimicrobial resistance. Although some alternative products are commercially available, little is known on their potential impact on flock health and productivity. A prospective study involving 1.55 million birds was conducted on eight commercial broiler farms in Québec, Canada, to evaluate the impact of replacing antibiotic growth promoters and anticoccidial drugs by a drug-free program including improved brooding conditions, anticoccidial vaccination, essential oil-based feed additives, and water acidification. Various productivity and health parameters were compared between barns allocated to the conventional and the drug-free program. Zootechnical performances were monitored as productivity criteria. Clinical necrotic enteritis and subclinical enteritis occurrences, litter and fecal moistures content were measured, and microscopic gut health was evaluated. Clostridium perfringens and Campylobacter spp. strains were recovered from fecal samples collected during farm visits. Clostridium perfringens counts were used as poultry health indicators and Campylobacter prevalence was noted as well. The drug-free program was associated with a significant increase in feed conversion ratio and a decrease in mean live weight at slaughter and in daily weight gain. An increased incidence of necrotic enteritis outbreaks and subclinical enteritis cases, as well as an increase in litter moisture content at the end of the rearing period were also observed for this program. Mean microscopic intestinal lesion scores and prevalence of Campylobacter colonization were not statistically different between the two groups but the drug-free program was associated with higher Clostridium perfringens isolation rates. According to the current study design, the results suggest that substitution of antibiotic growth promoters and anticoccidial drugs by a drug-free program impacts various broiler chicken production parameters and Clostridium perfringens carriage levels.

Towards the control of necrotic enteritis in broiler chickens with in-feed antibiotics phasing-out worldwide

Poultry production has undergone a substantial increase compared to the livestock industries since 1970. However, the industry worldwide is now facing challenges with the removal of in-feed antibiotics completely or gradually, as the once well-controlled poultry diseases have re-emerged to cause tremendous loss of production. Necrotic enteritis (NE) is one of the most important diseases which costs the industry over two billion dollars annually. In this paper, we review the progress on the etiology of NE and its control through dietary modifications, pre- and probiotics, short chain fatty acids, and vaccination. The other likely measures resulted in the most advances in the toxin characterization are also discussed. Vaccine strategies may have greater potential for the control of NE mainly due to clearer etiology of NE having been elucidated in recent years with the identification of necrotic enteritis toxin B-like (NetB) toxin. Therefore, the use of alternatives to in-feed antibiotics with a better understanding of the relationship between nutrition and NE, and limiting exposure to infectious agents through biosecurity and vaccination, might be a tool to reduce the incidence of NE and to improve gut health in the absence of in-feed antibiotics. More importantly, the combinations of different measures may achieve greater protection of birds against the disease. Among all the alternatives investigated, prebiotics, organic acids and vaccination have shown improved gastrointestinal health and thus, have potential for the control of NE.

Comparison of single and blend acidifiers as alternative to antibiotics on growth performance, fecal microflora, and humoral immunity in weaned piglets

The banning of the use of antibiotics as feed additive has accelerated investigations of alternative feed additives in animal production. This experiment investigated the effect of pure citric acid or acidifier blend supplementation as substitute for antibiotic growth promoters on growth performance, fecal microbial count, and humoral immunity in weaned piglets challenged with Salmonella enterica serover Typhimurium and Escherichia coli KCTC 2571. A total of 60 newly weaned piglets (crossbred, 28-d-old; average 8 kg initial weight) were randomly assigned to four dietary treatments in a completely randomized design. Dietary treatments included NC (negative control; basal diet), PC (positive control; basal diet+0.002% apramycin), T1 (basal diet+0.5% pure citric acid), and T2 (basal diet+0.4% acidifier blend). All piglets were orally challenged with 5 mL of culture fluid containing 2.3×10⁸ cfu/mL of E. coli KCTC 2571 and 5.9×10⁸ cfu/mL of S. typhimurium at the beginning of the experiment. The PC group showed the highest ADG and ADFI, whereas gain:feed was improved in the PC and T1 group (p<0.05). All dietary treatments showed significant reduction in fecal counts of Salmonella and E. coli, compared to NC (p<0.05), with PC being better than T1 and T2. Significant elevation in fecal Lactobacillus spp. counts was shown by treatments with T1, T2, and PC, whereas Bacillus spp. counts were increased by treatment with T1 and T2 compared to NC and PC diet (p<0.05). Serum IgG concentration was increased by T1 diet (p<0.05), whereas IgM and IgA were not significantly affected by any of the dietary treatments (p>0.05). From these above results, it can be concluded that, as alternatives to antibiotics dietary acidification with pure citric acid or acidifiers blend did not fully ameliorate the negative effects of microbial challenges in respect of growth performance and microbial environment, however improved immunity suggested further research with different dose levels.