Use Of Antibiotic Growth Promoters Research Articles

A novel Bacillus based multi-strain probiotic improves growth performance and intestinal properties of Clostridium perfringens challenged broilers

There is a necessity for the implementation of in-feed probiotics in the poultry production industry, following strict regulations around the use of antibiotic growth promoters (AGP). Bacillus spp. are becoming an attractive alternative because of their functionality and stability. This study aims to evaluate the effect of a novel multi-strain Bacillus based probiotic on growth performance and gut health in male Ross 308 broiler chickens challenged with Clostridium perfringens Type A. Broilers on a 4 phase feeding program were fed diets containing either a standard metabolizable energy (ME) (100%) or a reduced ME (98%) level. The test probiotic was compared to an un-supplemented negative control and a commercial benchmark product as positive control over a 35 D feeding trial, using a 2 × 3 factorial experimental design. Chicks were inoculated with a once-off dose of C. perfringens on day 14. Growth performance was measured weekly to calculate body weight (BW), feed intake (FI) and feed conversion ratio (FCR). Villi histomorphology, gut lesions, and liver weight were assessed at day 35. Broilers fed the reduced ME diet with the test probiotic achieved higher final BWs (P = 0.037) and FCR (P = 0.014) than the negative control. Broilers fed the standard ME diet with the test probiotic showed improved (P = 0.001) FCR than the negative control from day 21 onwards. Increased duodenal villi height (P = 0.012) and villi height to crypt depth ratio in the duodenum (P < 0.0001) and jejunum (P = 0.0004) were observed in broilers fed the reduced ME diet containing the test probiotic. Additionally, the test probiotic resulted in significantly reduced relative liver weights in both ME groups. Consequently, the results suggest that the novel multi-strain Bacillus based probiotic enhanced broiler performance and improved gut health and is thus attractive as an alternative to AGP's in broiler production.

Role of Aloe Vera as A Natural Feed Additive in Broiler Production

Phytogenic feed additives have replaced the use of antibiotic growth promoters (AGP) in the diet of poultry particularly broiler chickens. Researchers are moving towards the use of natural products such as herbs, spices, plants and plant products, which possess influential effects on growth performance parameters, immune response and treatment of various diseases. Aloe vera is a well-known medicinal plant and is being used for commercial and therapeutic purposes such as antimicrobials, antitumor, anti-inflammatory, immunomodulator, wound healing, antioxidant and antiprotozoal agents. From a few last decades, the use of Aloe vera has been increased as a natural additive to broiler diet. Based on the review of literature, Aloe vera can improve immune response, growth performance in the broiler, as well as an excellent alternative of AGPs and anticoccidial drugs. It can be used for broiler diet in the form of gel, powder, ethanolic extract and aqueous extract. This review provides information about the use of Aloe vera in broiler production with reference to the effects on growth performance, immune system, intestinal microflora and coccidiosis in broiler chickens.

The potential of extract of Zingiber zerumbet (L.) Smith as a feed additive to improve the production performances and meat nutritional composition of broiler chickens

This study aimed at replacing the use of antibiotic growth promoters (AGP) as the feed additive with the Zingiber zerumbet (L.) Smith extract (ZZE) to control Salmonellosis in broiler chickens. This study employed the completely randomized design (CRD), five treatments, namely: T0 (basal diet), T1 (basal diet + S. enteridis infection), T2 (basal diet + S. enteridis infection + 0.33 % ZZE), T3 (basal diet + S. enteridis infection + 0.67 % ZZE), and T4 (basal diet + S. enteridis infection + 1 % ZZE). The addition of the Z. zerumbet extract did not seem to affect the production performances, in which the average feed consumption was 69.38 g ± 4.43 g to 72.71 g ± 4.92 g, body weight gain was 35.67 g ± 1.40 g to 38.30 g ± 3.85 g, feed conversion was 1.89 ± 0.11 to 2.04 ± 0.11, final weight was 1 287.80 g ± 49.97 g up to 1 380.50 g ± 134.90 g, and percentage of carcass was 60.90 % to 68.48 %. However, the use of Z. zerumbet extract with the highest concentration at 1 % decreased the crude fat of meat.

Dietary Fiber and Intestinal Health of Monogastric Animals.

Animal performance, feed efficiency, and overall health are heavily dependent on gut health. Changes in animal production systems and feed regulations away from the use of antibiotic growth promoters (AGP) have necessitated the identification of strategies to optimize gut health in novel and effective ways. Among alternatives to AGP, the inclusion of dietary fibers (DF) in monogastric diets has been attempted with some success. Alternative feedstuffs and coproducts are typically rich in fiber and can be used in the diets to reduce feed costs and optimize gut health. DF are naturally occurring compounds with a diverse composition and are present in all plant-based feedstuffs. DF stimulate the growth of health-promoting gut bacteria, are fermented in the distal small intestine and large intestine to short-chain fatty acids and have beneficial effects on the immune system. Maternal DF supplementation is one novel strategy suggested to have a beneficial programming effect on the microbial and immune development of their offspring. One mechanism by which DF improves gut health is through maintenance of an anaerobic intestinal environment that subsequently prevents facultative anaerobic pathogens from flourishing. Studies with pigs and poultry have shown that fermentation characteristics and their beneficial effects on gut health vary widely based on type, form, and the physico-chemical properties of the DF. Therefore, it is important to have information on the different types of DF and their role in optimizing gut health. This review will provide information and updates on different types of DF used in monogastric nutrition and its contribution to gut health including microbiology, fermentation characteristics, and innate and adaptive immune responses.

Phorbol 12-Myristate 13-Acetate-Induced Changes in Chicken Enterocytes.

Increased intestinal epithelial permeability has been linked to many enteric diseases because it allows easy access of microbial pathogens and toxins into the system. In poultry production, the restrictions in the use of antibiotic growth promoters have increased the chances of birds being susceptible to different enteric diseases. Thus, understanding the mechanisms which compromise intestinal function is pertinent. Based on our previous observation which showed the primary chicken enterocytes in culture undergoing dystrophic changes on treatment with phorbol myristate acetate (PMA), we surmised that this model, which appeared to mimic increased intestinal permeability, may help to understand the mechanisms of this problem. As genomic and proteomic changes are associated with many physiological and pathological problems, we were interested to find whether certain proteomic changes underlie the morphological alterations in the enterocytes induced by PMA. We exposed primary enterocyte cultures to a sub-lethal concentration of PMA, extracted the proteins, and analyzed by mass spectrometry for differentially regulated proteins. Our results showed that PMA affected several biological processes which negatively affected their energy metabolism, nuclear activities, and differentially regulated the levels of several stress proteins, chaperon, cytoskeletal, and signal transduction proteins that appear to be relevant in the cause of enterocyte dystrophy. Phorbol myristate acetate-affected signal transduction activities also raise the possibilities of their increased susceptibility to pathogens. The changes in enterocyte integrity can make intestine vulnerable to invasion by microbial pathogens and disrupt gut homeostasis.

Lactobacillus elicits a 'Marmite effect' on the chicken cecal microbiome

The poultry industry has traditionally relied on the use of antibiotic growth promoters (AGPs) to improve production efficiency and minimize infection. With the recent drive to eliminate the use of AGPs, novel alternatives are urgently required. Recently attention has turned to the use of synthetic communities that may be used to ‘seed’ the developing microbiome. The current challenge is identifying keystone taxa whose influences in the gut can be leveraged for probiotic development. To help define such taxa we present a meta-analysis of 16S rRNA surveys of 1572 cecal microbiomes generated from 19 studies. Accounting for experimental biases, consistent with previous studies, we find that AGP exposure can result in reduced microbiome diversity. Network community analysis defines groups of taxa that form stable clusters and further reveals Lactobacillus to elicit a polarizing effect on the cecal microbiome, exhibiting relatively equal numbers of positive and negative interactions with other taxa. Our identification of stable taxonomic associations provides a valuable framework for developing effective microbial consortia as alternatives to AGPs.

Simultaneous Supplementation of Bacillus subtilis and Antibiotic Growth Promoters by Stages Improved Intestinal Function of Pullets by Altering Gut Microbiota.

Early nutrition of pullets could determine the overall development and the performance of laying hens. With the aim to reduce the use of antibiotic growth promoters (AGPs) and to maintain the growth and development of pullets, the effect of simultaneous short-termed supplementation of AGPs (bacitracin zinc 20 mg/kg and colistin sulfate 4 mg/kg) and Bacillus subtilis (B. subtilis) DSM17299 probiotic, as well as the effect of supplementation of AGPs (bacitracin zinc 20 mg/kg and colistin sulfate 4 mg/kg) during the whole period (0~16 weeks) on the overall growth and development, intestinal health, and caecal microbiota of pullets were evaluated. In the present study, a total of 630 one-day-old Hy-Line Brown layers were randomly distributed into five equal groups: including the AGPs group (supplemented with AGPs based on basal diets for 16 weeks), the BA3 group (supplemented with AGPs and B. subtilis based on basal diets for 3 weeks), the BA6 group (for 6 weeks), the BA12 group (for 12 weeks), and the BA16 group (for 16 weeks). When compared with the AGPs group, the supplementation of AGPs + B. subtilis for the first 3 weeks could maintain overall growth performance, including the average body weight, average feed intake, average daily weight gain, and feed conversion ratio of pullets at 3, 6, 12, and 16 weeks of age (P > 0.05). Meanwhile, the characteristic growth indexes in different periods were separately measured. At 3 weeks of age, the amylase activity in ileum was elevated (P = 0.028), and the length of tibia was up to the standard in the BA3 group. At 12 weeks of age, the increased villus height (P = 0.046) of jejunum, increased villus height (P = 0.023) and ratio of villus height to crypt depth (P = 0.012) of ileum, decreased crypt depth (P = 0.002) of ileum, and elevated mRNA levels of sucrase in jejunum (P < 0.05) were all identified in the BA3 group. At 16 weeks of age, the secreted immunoglobulin A (sIgA) content in the jejunum mucosa of the BA3 group was greater than the other groups (P < 0.001). Furthermore, altered intestinal microbiota was found in the BA3 group. Specifically, decreased amounts of Alistipes, Bacteroides, Odoribacter, Dehalobacterium, and Sutterella and increased amounts of Lactobacillus, Dorea, Ruminococcus, and Oscillospira were determined (P < 0.05) in the BA3 group at week 6. Meanwhile, decreased amounts of B. fragilis and C. leptum (P < 0.05) were identified in the BA3 group at week 12, which were found to be relevant for the improvement of intestinal morphology (P < 0.05) by Pearson analysis. In conclusion, simultaneous supplementation of AGP and B. subtilis for 0~3 weeks increased the relative abundance of beneficial microbiota in caecum in 0~6 weeks, then improved the intestinal morphology by elevating populations of B. fragilis and C. leptum in 7~16 weeks, and further upregulated sucrase expression and increased sIgA content in the intestinal mucosa in 13~16 weeks.

Immunity, immunomodulation, and antibiotic alternatives to maximize the genetic potential of poultry for growth and disease response

Multiple challenges confront the increasing demand for wholesome poultry food products, including governmental restrictions on the use of antibiotic growth promoters (AGPs), nutritional requirements to obtain maximum growth potential, understanding crosstalks among the immunity–microbiota–neuroendocrine system in the gut to maximize intestinal efficiency, high-density production conditions, waste management, and the emergence of infectious pathogens, particularly those that emerge in the antibiotic-free animal production environment. Although in-feed antibiotics have dramatically increased the efficiency of commercial poultry production over the last 50 years, we are now faced with an increasing global crisis concerning the heightened use of antibiotics in animal agriculture and the emergence of multidrug-resistant superbugs that threaten disease management in animals and humans. Therefore, much interest has focused on the development of alternative, antibiotic-free methods of commercial poultry production. Initially, alternatives to antibiotics included any strategies that replace AGPs, but now include any feed additives or treatment that will allow antibiotic-free animal production to prevent and/or treat diseases. These newer disease control strategies can be classified broadly into those that are directly cytotoxic against infectious agents or remove pathogenic toxins, including vaccines, hyperimmune antibodies, antimicrobial peptides, and bacteriophages, and those that augment non-specific host immunity and gut health, including phytochemicals, adjuvants, prebiotics, and probiotics. Furthermore, because the gut microbiota influences various physiological aspects of the immune response, brain function, and gut health, most antibiotic alternatives are expected to promote beneficial microbes that will benefit host physiological responses. However, there is a timely need to better understand the role of the microbiota in gut health if we want to use microbes to modulate the host response to enhance growth performance. This review will highlight current knowledge of host immunity in poultry, and various strategies to modulate host immunity, growth performance, and disease responses to guide the development of alternatives to reduce the use of antibiotics, using a few selected alternatives and a description of their efficacy and modes of action.

Bile salt hydrolases: Structure and function, substrate preference, and inhibitor development.

The worldwide trend of limiting the use of antibiotic growth promoters (AGPs) in animal production creates challenges for the animal feed industry, thus necessitating the development of effective non-antibiotic alternatives to improve animal performance. Increasing evidence has shown that the growth-promoting effect of AGPs is highly correlated with the reduced activity of bile salt hydrolase (BSH, EC 3.5.1.24), an intestinal bacteria-producing enzyme that has a negative impact on host fat digestion and energy harvest. Therefore, BSH inhibitors may become novel, attractive alternatives to AGPs. Detailed knowledge of BSH substrate preferences and the wealth of structural data on BSHs provide a solid foundation for rationally tailored BSH inhibitor design. This review focuses on the relationship between structure and function of BSHs based on the crystal structure, kinetic data, molecular docking and comparative structural analyses. The molecular basis for BSH substrate recognition is also discussed. Finally, recent advances and future prospectives in the development of potent, safe, and cost-effective BSH inhibitors are described.

Effectiveness of bioactive combinations of several plant substances to inhibit the growth of Escherichia coli and Salmonella sp.

The use of antibiotic growth promoters (AGP) has been banned as feed additives in many countries, therefore the alternatives need to be found. An in vitro experiment was conducted to study the potential of combination of some plant extract to inhibit growth of pathogen bateria that normally occur in the poultry gastro intestinal tract.The combination of three plants bioactives (liquid smoke of cashew shells of Anacardium occidentaleor CLS, Phyllanthus niruri L. extract (EM), and Synzygium aromaticum extract (EDC) were formulated and evaluated for its effectiveness to inhibit growth of Escherichia coli and Salmonella sp. in vitro.The mixtures (KE) were then made in 3 different concentrations, i.e. 100 % KE, 50% KE, and 25% KE and studied their effectiveness to inhibit growth of E. coli or Salmonella sp. using microplate reader method. The results showed that the higher the concentration of the bioactive combination (KE100) the higher the ability to inhibit the growth of E. coli or Salmonella sp. The combination of bioactive substances CAM, EM, and EDC more effectively than Zn-bacitracin antibiotics to inhibit the growth of E. coli and Salmonella sp. The optimum concentration of KE with the similar effectiveness as the AGP was 25%. It was concluded that the combination of CAM, EM, and EDC was able to inhibit the growth of E. coli and even capable to eliminate the presence of Salmonella sp. In the biological assay, a combination of CAM, EM, and EDC either extract or powder form, high dose, medium or low does not affect the weight of the spleen, bursa fabricius, and blood profile. The best combination of CAM, EM, and EDC extracts to decreases the total bacterial population and E. coli was middle dose ie 0.0625% (extract) and 0.625% (powder). Likewise for live weight gain that was a good dose of extract or powder form can replace antibiotics. It was concluded that combinations of CAM, EM, and EDC had potential as a substitute for AGP in poultry feed, especially chickens.

Effects of phytogenic feed additives on cellular oxidative stress and inflammatory reactions in intestinal porcine epithelial cells1.

Due to increasing concerns about the use of antibiotic growth promoters (AGP) in livestock production and their complete ban in the European Union in 2006, suitable alternatives are urgently needed. Among others, anti-inflammatory activities of AGP are discussed as their putative mode of action. As numerous phytochemicals are known to modulate the cellular antioxidant capacity and immune response, we studied the antioxidative and anti-inflammatory properties of a phytogenic (plant-derived) feed additive (PFA) in intestinal porcine epithelial cells (IPEC-J2). The effects of the PFA were compared with those of selected phytogenic ingredients (grape seed extract [GRS], licorice extract [LIC], menthol [MENT], methyl salicylate [MES], oak bark extract [OAK], oregano essential oil [ORE], and a plant powder mix [PLA]), and with the effects of the AGP tylosin (TYL). Oxidative or inflammatory stress was induced by stimulating IPEC-J2 with hydrogen peroxide (H2O2; 0.5 mM) or tumor necrosis factor alpha (TNF-α; 10 ng/mL), respectively. The antioxidative effects of feed additives were assessed with a reactive oxygen species (ROS)-sensitive probe and by measuring the expression of 6 antioxidative target genes via quantitative real-time PCR (RT-qPCR). Anti-inflammatory potential was analyzed using a nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) reporter gene assay. Moreover, the expression levels of 6 NF-κB target genes were measured using RT-qPCR analysis, and the release of IL-6 was analyzed via ELISA. Significant decreases in cellular ROS upon H2O2 treatment were observed for the PFA (P < 0.001), LIC (P < 0.001), ORE (P < 0.05), and GRS (P < 0.01). No significant changes in the expression of antioxidative genes were found. NF-κB activation upon TNF-α treatment was significantly inhibited by the PFA (P < 0.05) and by ORE (P < 0.001). Moreover, the PFA and ORE significantly reduced the gene expression of IL-6 (P < 0.001), IL-8 (P < 0.001), and C-C motif chemokine ligand 2 (CCL2; P < 0.05), as well as the release of IL-6 (P < 0.05). The other phytogenic compounds as well as the AGP TYL did not significantly affect any of the inflammatory parameters. In summary, we revealed the antioxidative properties of the PFA, LIC, ORE, and GRS, as well as anti-inflammatory properties of the PFA and ORE in IPEC-J2, providing a better understanding of the mode of action of this PFA under our experimental conditions.

Stevia (&lt;i&gt;Stevia rebaudiana Bertoni&lt;/i&gt;): un aditivo natural efectivo en avicultura?

En avicultura, la restricción de usar antibióticos promotores del crecimiento tanto en el nivel nacional como internacional y la demanda de los consumidores de productos naturales, han originado la búsqueda de aditivos de origen natural. Así surgen distintos agregados dietarios, denominados en su conjunto promotores naturales del crecimiento (PNC), que comprenden prebióticos, probióticos, simbióticos, ácidos orgánicos, enzimas y fitogénicos. Dentro de estos últimos, encontramos la Stevia (Stevia rebaudiana Bertoni), endulzante en humanos, que en animales de interés productivo aumenta la eficiencia productiva de los mismos. Además, según se utilicen los tallos, las hojas o sus extractos, empleando diferentes metodologías de extracción, se obtienen variados componentes bioactivos con distintos mecanismos de acción. En general, dichos componentes presentan propiedades antioxidantes, antimicrobianas, antitumorales y antifúngicas; inclusive tienen efectos positivos sobre el sistema inmunológico. En aves, estos compuestos bioactivos mejoran la eficiencia productiva en pollos, sobre todo en las primeras semanas de vida y en adultos no dejan residuos en la carne o los huevos para mejorar la salud intestinal de las aves en las primeras semanas de vida. De este modo, la Stevia o sus compuestos bioactivos serían buenas alternativas para mejorar la salud intestinal en las primeras semanas de vida, lo que se reflejaría posteriormente en una mayor eficiencia productiva y mejor calidad de la canal en aves adultas.

Growth-Promoting and Antioxidant Effects of Magnolia Bark Extract in Chickens Uninfected or Co-Infected with Clostridium perfringens and Eimeria maxima as an Experimental Model of Necrotic Enteritis

BackgroundMagnolia tree bark has been widely used in traditional Asian medicine. However, to our knowledge, no studies have been reported investigating the effects of dietary supplementation with magnolia bark extract in chickens. ObjectiveWe tested the hypothesis that dietary supplementation of chickens with a Magnolia officinalis bark extract would increase growth performance in uninfected and Eimeria maxima/Clostridium perfringens co-infected chickens. MethodsA total of 168 chickens were fed from hatch either a standard diet or a diet supplemented with 0.33 mg or 0.56 mg M. officinalis bark extract/kg (M/H low or M/H high, respectively) from days 1 to 35. At day 14, half of the chickens were orally infected with E. maxima, followed by C. perfringens infection at day 18 to induce experimental avian necrotic enteritis. Daily feed intake, feed conversion ratio, body weight gain, and final body weight were measured as indicators of growth performance. Serum α1-acid glycoprotein (AGP) concentrations were measured as an indicator of systemic inflammation, and intestinal lesion scores were determined as a marker of disease progression. Transcript levels for catalase, heme oxygenase 1, and superoxide dismutase in the intestine, liver, spleen, and skeletal muscle were measured as indicators of antioxidant status. ResultsGrowth performance increased between days 1 and 35 in uninfected and E. maxima/C. perfringens co-infected chickens fed M/H-low or M/H-high diets compared with unsupplemented controls. Gut lesion scores were decreased, whereas AGP concentrations were unchanged, in co-infected chickens fed magnolia-supplemented diets compared with unsupplemented controls. In general, transcripts for antioxidant enzymes increased in chickens fed magnolia-supplemented diets compared with unsupplemented controls, and significant interactions between dietary supplementation and co-infection were observed for all antioxidant enzyme transcript levels. ConclusionMagnolia bark extract might be useful for future development of dietary strategies to improve poultry health, disease resistance, and productivity without the use of antibiotic growth promoters.

Influence of silver nanoparticles on growth and health of broiler chickens after infection with Campylobacter jejuni

BackgroundSilver nanoparticles (AgNP) have gained much attention in recent years due to their biomedical applications, especially as antimicrobial agents. AgNP may be used in poultry production as an alternative to the use of antibiotic growth promoter. However, little is known about the impact of oral administration of AgNP on the gut microbiota and the immune system. The aim of the present study was to investigate the effects of AgNP on growth, hematological and immunological profile as well as intestinal microbial composition in broilers challenged with Campylobacter jejuni (C. jejuni).ResultsAgNP did not affect the intestinal microbial profile of birds. The body weight gain and the relative weights of bursa and spleen were reduced when supplemented with AgNP. There was no difference with respect to packed cell volume. However, the plasma concentrations of IgG and IgM were lower in birds receiving AgNP compared to the non-supplemented control group. The expression of TNF-α and NF-kB at mRNA level was significantly higher in birds receiving AgNP.ConclusionsThe application of AgNP via the drinking water in the concentration of 50 ppm reduced broiler growth, impaired immune functions and had no antibacterial effect on different intestinal bacterial groups, which may limit the applicability of AgNP against C. jejuni in broiler chickens.

Use of Organic Acids and A Competitive Exclusion Product as Growth Promoter and Salmonella Enteritidis Control in Commercial Turkeys

ABSTRACT It is estimated that Salmonella causes one million illnesses in the United States annually, with 19,000 hospitalizations and 380 deaths. There are various serotypes of this bacterium, and the serotypes Typhimurium and Enteritidis are commonly isolated from outbreaks and, in most cases, present resistance to the antibiotics utilized in clinical medicine. One of the current theories to explain the emergence of bacterial resistance is the continuous use of antibiotics as growth promoters in animal feeds. Despite the lack of evidences that antibiotic growth promoters cause bacterial resistance, the poultry industry has explored strategies to reduce or to eliminate the use of antibiotic growth promoters in the production chain, including the improvement of biosecurity programs, use of vaccines, genetic selection, and the feeding of other additives, such as organic acid blends (OAB) and competitive exclusion (CE) products. This study aimed at evaluating the effect of the continuous dietary supplementation of an OAB and a CE product on the growth performance, pH of the crop and cecal contents, control of Salmonella Enteritidis (SE) in the cecal content, and acute-phase protein serum levels in starter commercial turkeys. The additives promoting similar results as antibiotics under controlled experimental conditions should be further evaluated on commercial farms to allow their utilization under practical conditions. Supplementing commercial turkey diets with the evaluated OAB and CE product may reduce SE load. Serum OVT and AGP levels can be used as effective and fast indicators of infection, including that by SE.

English

The ban on use of antibiotic growth promoter for fattening chickens has created demand for other weight and health promoting supplements. Phytogens, and especially essential oils (EO) or their components, have attracted great interest. They are considered 'natural' and leaving no unwanted tissue residue. The aim of this study was to evaluate the effect of XTRACT (R) (carvacrol, cinnamaldehyde and capsicum oleoresin) and natural zeolite clinoptilolite as feed additives in broiler chicken. Addition of XTRACT (R) and/or zeolite had positive influence at antioxidative enzymes SOD and GPx during chicken fattening. This indirectly resulted in higher final body weight of chicken. Lower lipid peroxidation in breast meat and drumsticks was also observed in experimental groups. The sensory quality of chicken breast meat and drumstick meat, expressed as color, structure, juiciness, tenderness, odor and taste acceptability was improved in experimental groups.

Phage-mediated dissemination of virulence factors in pathogenic bacteria facilitated by antibiotic growth promoters in animals: a perspective.

Addition of sub-therapeutic antibiotics to the feed of food-producing animals for growth promotion and disease prevention has become a common agricultural practice in many countries. The emergence of antibiotic-resistant pathogens is a looming concern associated with the use of antibiotic growth promoters (AGPs) around the world. In addition, some studies have shown that AGPs may not only affect antibiotic resistance but may also stimulate the dissemination of virulence factors via bacteriophages. Although only a few studies are currently available in the literature regarding this topic, in this article we endeavor to provide a perspective about how AGPs would impact the transmission of virulence factors by horizontal gene transfer via phages in a few pathogenic bacterial species significant to livestock production.

Prohibition of antibiotic growth promoters has affected the genomic profiles of Lactobacillus salivarius inhabiting the swine intestine.

After the introduction of a ban on the use of antibiotic growth promoters (AGPs) for livestock, the feeding environment, including the composition of animal intestinal microbiota, has changed rapidly. We hypothesized that the microbial genomes have also been affected by this legal prohibition, and investigated an important member of the swine gut microbiota, Lactobacillus salivarius, with a pan-genomic approach. Here, we isolated 21 L. salivarius strains composed of 6 strains isolated before the AGP prohibition (SBPs) and 15 strains isolated after the AGP prohibition (SAPs) at an interval of a decade, and the draft genomes were generated de novo. Several genomic differences between SBPs and SAPs were identified, although the number and function of antibiotic resistance genes were not different. SBPs showed larger genome size and a higher number of orthologs, as well as lower genetic diversity, than SAPs. SBPs had genes associated with the utilization of L-rhamnose and D-tagatose for energy production. Because these sugars are also used in exopolysaccharide (EPS) synthesis, we tried to identify differences in biofilm formation-associated genes. The genes for the production of EPSs and extracellular proteins were different in terms of amino acid sequences. Indeed, SAPs formed dense biofilm and survived better than SBPs in the swine intestinal environment. These results suggest that SAPs have evolved and adapted to protect themselves from new selection pressure of the swine intestinal microenvironment by forming dense biofilms, adopting a distinct antibiotic resistance strategy. This finding is particularly important to understand the evolutionary changes in host-microbe interaction and provide detailed insight for the development of effective probiotics for livestock.

Performance, biochemical and haematological responses, and relative organ weights of laying hens fed diets supplemented with prebiotic, probiotic and synbiotic

BackgroundThe increasing trend of ban on the use of antibiotic growth promoters (AGPs) across the globe in the poultry industry has led to a growing need for alternatives to AGPs. Prebiotic, probiotic and their combination as a synbiotic have been considered as potential alternatives. This study aimed to investigate the effects of a prebiotic (isomaltooligosaccharide, IMO), a probiotic (PrimaLac®), and their combination (synbiotic) on hen performance, biochemical and haematological responses, and relative organ weights from 20 to 52 weeks of age.ResultsSupplementation of 1% IMO (PRE), 0.1% PrimaLac® (PRO) and 1% IMO + 0.1% PrimaLac® (SYN) improved (P < 0.05) feed intake and egg production at 20–36 weeks of age; body weight gain, feed conversion ratio and egg mass at 20–36 and 20–52 weeks of age; and egg weight at 20–36, 37–52 and 20–52 weeks of age. Compared to control-fed hens at 20–36 weeks of age, PRO- and SYN-fed hens produced less (P < 0.05) small size eggs while SYN-fed hens produced more large size eggs. From 37 to 52 weeks of age, PRE-, PRO- or SYN-fed hens produced less (P < 0.05) medium size eggs, and more large and extra-large size eggs. PRE, PRO or SYN supplementation decreased (P < 0.05) the serum total cholesterol at 36 weeks of age, and serum low-density lipoprotein (LDL) cholesterol, alanine aminotransferase (ALT) and alkaline phosphatase (ALP) at 36 and 52 weeks of age. At 36 and 52 weeks of age, supplementation of PRE, PRO or SYN increased (P < 0.05) lymphocyte percentage and decreased (P < 0.05) heterophil percentage, leading to a lower heterophil to lymphocyte (H/L) ratio. No significant differences were observed in the relative weights of the heart, liver, ovary, pancreas and spleen of all dietary treatment groups.ConclusionsSupplementation of PRE, PRO or SYN improved performance, serum total cholesterol, LDL cholesterol, ALT, ALP and H/L ratio of hens from 20 to 52 weeks of age. These results demonstrated the use of PRE, PRO and SYN as alternative feed additives to AGPs for improving the health and productivity of hens, while PRO is the best for commercial layer production to yield maximum profit.

Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population.

Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.