Use of antibiotics in broiler production: Global impacts and alternatives

Effects of Bacillus subtilis, butyrate, mannan-oligosaccharide, and naked oat (ß-glucans) on growth performance, serum parameters, and gut health of broiler chickens

Four nonantibiotic alternative growth promoters for broiler chickens were evaluated. Ross 308 chicks were fed a control diet (mainly corn and soybean meal) or a diet supplemented with a probiotic (Bacillus subtilis Gallipro DSM 17299), encapsulated butyric acid (Novyrate C), mannan-oligosaccharide (Actigen MOS) or formulated with 20% naked oat (starter diet) and 30% naked oat (grower and finisher). The study was carried out as a complete random blocked design with 10 pens for each diet, 45 birds per pen. Compared to the control, the naked oat diet improved the average daily gain by 16% during the starter phase (up to d 10). The probiotic did so during the grower phase as did butyric acid in the finisher phase (up to d 34). For the experiment overall, the probiotic decreased average daily gain slightly. The best improvement in feed conversion ratio was obtained in the butyrate group (5%). No significant treatment effect on crop pH or on mortality was observed. The naked oat diet gave a slightly lower cecum pH on d 34. The MOS supplement decreased jejunal mass on d 34 and increased villus length (34%) and villus height/crypt depth ratio (32%) measured on d 10. Naked oat, butyric acid and MOS diets all reduced serum endotoxin levels. The probiotic increased serum C-reactive protein. All noncontrol diets reduced serum malondialdehyde. The naked oat diet reduced d 34 litter pH by about 0.3. Some effects of the proposed non-antibiotic growth promoters have been observed and could contribute to livestock performance. Their exact modes of action remained to be defined.

Effects of Supplementation of Brassica Juncea Seed Extract in Drinking Water on Intestinal Histomorphometry, Bacteriology, and Serum Biochemistry Parameters of Broiler Chicken

Brassica juncea (B. juncea) is an erect, and often an unbranched plant that belongs to the family Brassicaceae. The plant's seeds have been used in many countries as a folk remedy to treat considerable common and chronic diseases. The current study aimed to investigate the possible effects of B. juncea seed extract supplementation in the drinking water as an alternative antibiotic growth promoter on poultry production. In a completely randomized design, 308 unsexed Ross broilers were allocated into 4 treatments with4 replicates, and each replicate was run on10 birds. Aqueous B. juncea seeds extract (MSE) was administered to drinking water at levels of 0, 3, 5, and 7 ml/liter to T1, T2, T3, and T4, respectively, from day 1to day 35. No significant effects were reported regarding jejunum villi height and villi thickness (P≥0.05). However, the ratio of villus height to crypt depth was increased (P<0.05), and the crypt depth was reduced (P<0.05) in birds that had been fed B. juncea seeds extract, compared to control treatment (T1) at 35 day. The B. juncea seeds extract (MSE) at the level of 7 ml (T4) yielded the highest serum total protein, phosphorus, and calcium. The T2, T3, and T4 had the lowest values of cholesterol (160, 180mg /L) and the highest value (P<0.05) of alkaline phosphatase. On day 35, the birds receiving different levels of B. juncea seed extract had lower total aerobic bacteria counts in the ileum, compared to birds fed with control treatment. The administration of B. juncea seeds extract at 3, 5, and 7 ml levels can be added to drinking water to improve gut morphology, blood biochemical traits, and intestinal bacterial load.

A systematic review from basics to omics on bacteriophage applications in poultry production and processing

The growing human population is currently facing an unprecedented challenge on global food production and sustainability. Despite recognizing poultry as one of the most successful and rapidly growing food industries to address this challenge; poultry health and safety remain major issues that entail immediate attention. Bacterial diseases including colibacillosis, salmonellosis, and necrotic enteritis have become increasingly prevalent during poultry production. Likewise, outbreaks caused by consumption of undercooked poultry products contaminated with zoonotic bacterial pathogens such as Salmonella, Campylobacter and Listeria, are a serious public health concern. With antimicrobial resistance problem and restricted use of antibiotics in food producing animals, bacteriophages are increasingly recognized as an attractive natural antibacterial alternative. Bacteriophages have recently shown promising results to treat diseases in poultry, reduce contamination of carcasses, and enhance the safety of poultry products. Omics technologies have been successfully employed to accurately characterize bacteriophages and their genes/proteins important for interaction with bacterial hosts. In this review, the potential of using lytic bacteriophages to mitigate the risk of major poultry-associated bacterial pathogens are explored. This study also explores challenges associated with the adoption of this technology by industries. Furthermore, the impact of omics approaches on studying bacteriophages, their host interaction and applications is discussed.

Butyric and Citric Acids and Their Salts in Poultry Nutrition: Effects on Gut Health and Intestinal Microbiota

Intestinal dysfunction of farm animals, such as intestinal inflammation and altered gut microbiota, is the critical problem affecting animal welfare, performance and farm profitability. China has prohibited the use of antibiotics to improve feed efficiency and growth performance for farm animals, including poultry, in 2020. With the advantages of maintaining gut homeostasis, enhancing digestion, and absorption and modulating gut microbiota, organic acids are regarded as promising antibiotic alternatives. Butyric and citric acids as presentative organic acids positively impact growth performance, welfare, and intestinal health of livestock mainly by reducing pathogenic bacteria and maintaining the gastrointestinal tract (GIT) pH. This review summarizes the discovery of butyric acid (BA), citric acid (CA) and their salt forms, molecular structure and properties, metabolism, biological functions and their applications in poultry nutrition. The research findings about BA, CA and their salts on rats, pigs and humans are also briefly reviewed. Therefore, this review will fill the knowledge gaps of the scientific community and may be of great interest for poultry nutritionists, researchers and feed manufacturers about these two weak organic acids and their effects on intestinal health and gut microbiota community, with the hope of providing safe, healthy and nutrient-rich poultry products to consumers.

Effect of supplemental glycerol monolaurate and oregano essential oil blend on the growth performance, intestinal morphology, and amino acid digestibility of broiler chickens

Background

This experiment tested the impact of the combined supplementation of glycerol monolaurate (GLM) and oregano essential oil (EO) to broiler diets. Growth performance, metabolic response, immune status, apparent ileal digestibility coefficient (AID%), and intestinal histomorphology were assessed. Three-day-old Ross-308 broilers (76.62 g ± 0.50, n = 240) were randomly allocated into 4 experimental groups (6 replicates/group and 10 chicks/replicate). Birds were fed corn-soybean meal basal diets supplemented with four levels of GLM and oregano EO blend: 0, 0.15, 0.45, and 0.75% for 35 days.

Results

During the starter period, dietary GLM and oregano EO did not show significant (P > 0.05) changes in growth performance. During the grower period, GLM and oregano EO supplemented groups showed a linear and quadratic decline in FCR. During the finisher and overall performance, a linear increase in the body weight (BW), body weight gain (BWG), the protein efficiency ratio (PER), and relative growth rate (RGR), and a linear decrease in the FCR at 0.75% dietary level of GLM and oregano EO compared to the control. The broken-line regression model showed that the optimum dietary level of GLM and oregano EO blend was 0.58% based on final BW and FCR. The 0.45% or 0.15% dietary level of supplemented additives lowered (P < 0.05) the AID% of threonine and arginine, respectively, with no change in the AID% of other assessed amino acids at all dietary levels. Muscle thickness in jejunum and ileum in all dietary supplemented groups was increased (P < 0.05); however, such increase (P < 0.05) in the duodenum was shown at 0.45 and 0.75% dietary levels. All GLM and oregano EO supplemented groups showed increased (P < 0.05) duodenal, jejunal, and ileal villus height. The 0.15 and/or 0.75% dietary levels of supplemented additives increased (P < 0.05) the ileal and duodenal crypt depth, respectively, with a decreased (P < 0.05) duodenal crypt depth at 0.15% dietary level. The goblet cell count in ileum decreased (P < 0.05) in all GLM and oregano EO supplemented groups, but this decreased count (P < 0.05) was detected in jejunum at 0.45 and 0.75% dietary levels. The GLM and oregano EO supplemented groups did not show significant (P > 0.05) changes in the assessed metabolic and immune status parameters. Economically, the total return and performance index was increased at 0.75% dietary level.

Conclusion

Better growth performance was achieved at a 0.75 % dietary level of GLM and oregano EO by improving most intestinal morphometric measures. The optimum dietary level detected was 0.58%. The lack of influence of supplemented additives on chickens' immune and metabolic responses could indicate a lack of synergy between GLM and oregano EO.

Cooked broiler meat quality affected by different Mediterranean medicinal plants in the diet

Objective

This study was conducted to investigate the effects of adding oregano (Origanum syriacum L.) and germander (Teucrium polium L.) to poultry diets individually and/or in combination: i) on cooked chicken meat quality and storage stability, ii) to compare this effect with those of the synthetic antioxidant butylated hydroxyanisole (BHA) and with the normal basic diet (Control: without supplements).

Methods

Broilers (140 birds) were raised for 21 days and then equally divided into five different treatment groups of 28 birds each. The dietary treatments were as follows: i) control; ii) germander (GER, 1.5%); iii) oregano (ORE, 2.5%); iv) combination of GER and ORE (CM, 1.5%, and 2.5%); v) BHA (0.02%). Meat patties from the five treatments were prepared, cooked, and stored at 4°C prior to analysis. During storage, samples were measured for thiobarbituric acid-reactive substances (TBARS) and total carbonyl levels at 0, 4, and 7 days. In addition, cooked thigh meat was prepared separately to evaluate cooking loss and sensory attributes.

Results

The CM dietary treatment showed the highest antioxidant effect, with decreasing TBARS values (breast and thigh meat) throughout the storage time (4 to 7 days). Furthermore, ORE showed a higher antioxidant effect, decreasing the rancidity development (TBARS values), compared to the GER during the storage period (days 0 to 7). The anti-carbonyl effect of the CM supplement was the highest among all treatments from day 0 to 7. Generally, the antioxidant effect of GER was lower compared to that of ORE and BHA alone. The CM treatment most significantly decreased off-odor and rancidity development, with the lowest oxidation odor scores.

Conclusion

The results indicate that the combination of oregano and germander in the diet of boilers improves meat quality and prolongs shelf life.

Hulless barley and β-glucanase affect ileal digesta soluble beta-glucan molecular weight and digestive tract characteristics of coccidiosis-vaccinated broilers

Exogenous β-glucanase (BGase) in barley-based feed has been shown to reduce digesta viscosity in chickens, and thereby improve performance. Less well studied is the potential for BGase to convert barley β-glucan into low molecular weight carbohydrates, which might influence digestive tract function and enteric disease. Coccidiosis-vaccinated broiler chickens were fed graded levels of hulless barley (HB) and BGase to determine their effects on β-glucan depolymerization and digestive tract characteristics. Broilers were fed high β-glucan HB (0%, 30% and 60% replacing wheat) and BGase (0%, 0.01% and 0.1%) in a 3 × 3 factorial arrangement. A total of 5,346 broilers were raised in litter floor pens and vaccinated for coccidiosis on d 5. Each treatment was assigned to 1 pen in each of 9 rooms. The significance level was set at P ≤ 0.05. At both 11 and 33 d of broiler ages, peak molecular weight of β-glucan in ileal digesta decreased with increasing BGase for 30% and 60% HB. The maximum molecular weight for the smallest 10% β-glucan molecules (MW-10%) decreased with BGase at both ages for 30% and 60% HB; for birds fed 0% HB, only 0.1% BGase decreased MW-10%. The 0.1% BGase increased caecal short chain fatty acids (SCFA) compared to the 0.01% BGase at d 11 only for the 60% HB. Ileal pH increased with increasing HB and BGase at d 11 and 33. Caecal pH was lower for 0.1% BGase than 0% BGase for 60% HB at d 11. Relative mRNA expression of interleukin 6 (IL-6) and IL-8 in the ileum increased with 0.1% BGase at d 11 and 33, respectively, whereas expression of ileal mucin 2 (MUC2) decreased with 0.1% BGase at d 33. In the caeca, interactions between HB and BGase were significant for monocarboxylate transporter 1 (MCT1) and mucin 5AC (MUC5 AC) on d 11, but no treatment effects were found at d 33. In conclusion, BGase depolymerized high molecular weight β-glucan in HB in a dose-dependent manner. Hulless barley and BGase did not increase SCFA concentrations (except for 60% HB with 0.1% BGase at d 11) and caused minor effects on digestive tract histomorphological measurements and relative mRNA gene expression.

Probiotic Paenibacillus polymyxa 10 and Lactobacillus plantarum 16 enhance growth performance of broilers by improving the intestinal health

With the ever-growing strict prohibitions on antibiotic growth promoters (AGP) in animal production, in-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry. To investigate the effects of Paenibacillus polymyxa 10 and Lactobacillus plantarum 16 on the growth performance and intestinal health of broilers, 540 male Cobb 500 broilers of 1 d old were randomly divided into 3 groups with 6 replicates per group and 30 chicks per replicate. Broilers were fed with either a basal diet or basal diets supplemented with 1 × 108 colony-forming units (CFU)/kg P. polymyxa 10 (BSC10) or L. plantarum 16 (Lac16) for 42 d. Results showed that Lac16 treatment improved (P < 0.05) the growth performance (body weight and feed conversion) of broilers at the starter phase, while BSC10 treatment slightly improved (P > 0.05) the growth performance of the starter phase broilers. The increased villus height (P < 0.05) at d 14, 21 and 42 and villus height to crypt depth ratio (P < 0.05) at d 14 and 21 were observed in the ileum of the 2 probiotic groups. Besides, transmission electron microscopy results showed that the 2 probiotics enhanced the intestinal epithelial barrier. Both probiotic treatments up-regulated (P < 0.05) the mRNA expression of fatty acid binding protein 1 (FABP1) and sodium-dependent glucose transporters-1 (SGLT-1) in the ileal mucosa of broilers at d 21. In addition, BSC10 and Lac16 treatments significantly (P < 0.05) increased the relative abundance of short-chain fatty acids-producing bacteria, such as Butyricicoccus pullicaecorum, Faecalibacterium prausnitzii, Lachnospira and Coprococcu, and significantly (P < 0.05) decreased the relative abundance of enteric pathogens (Escherichia coli, Bacteroides fragilis and Shigella sonnei). Furthermore, the 2 probiotic treatments also increased the positive connection among the intestinal microbes and the carbohydrate metabolism-related pathways of the intestinal bacteria (P < 0.05), with decreasing (P < 0.05) nucleotides biosynthesis-related pathways of the intestinal bacteria. Overall, these results suggest that the 2 probiotics, especially Lac16, have a potential beneficial effect on the growth performance and intestinal health of starter phase broilers.

Longitudinal study on the effects of growth-promoting and therapeutic antibiotics on the dynamics of chicken cloacal and litter microbiomes and resistomes

BACKGROUND

Therapeutic and growth-promoting antibiotics are frequently used in broiler production. Indirect evidence indicates that these practices are linked to the proliferation of antimicrobial resistance (AMR), the spread of antibiotic-resistant bacteria from food animals to humans, and the environment, but there is a lack of comprehensive experimental data supporting this. We investigated the effects of growth promotor (bacitracin) and therapeutic (enrofloxacin) antibiotic administration on AMR in broilers for the duration of a production cycle, using a holistic approach that integrated both culture-dependent and culture-independent methods. We specifically focused on pathogen-harboring families (Enterobacteriaceae, Enterococcaceae, and Staphylococcaceae).

RESULTS

Antibiotic-resistant bacteria and antibiotic resistance genes were ubiquitous in chicken cloaca and litter regardless of antibiotic administration. Environment (cloaca vs. litter) and growth stage were the primary drivers of variation in the microbiomes and resistomes, with increased bacterial diversity and a general decrease in abundance of the pathogen-harboring families with age. Bacitracin-fed groups had higher levels of bacitracin resistance genes and of vancomycin-resistant Enterococcaceae (total Enterococcaceae counts were not higher). Although metagenomic analyses classified 28-76% of the Enterococcaceae as the commensal human pathogens E. faecalis and E. faecium, culture-based analysis suggested that approximately 98% of the vancomycin-resistant Enterococcaceae were avian and not human-associated, suggesting differences in the taxonomic profiles of the resistant and non-resistant strains. Enrofloxacin treatments had varying effects, but generally facilitated increased relative abundance of multidrug-resistant Enterobacteriaceae strains, which were primarily E. coli. Metagenomic approaches revealed a diverse array of Staphylococcus spp., but the opportunistic pathogen S. aureus and methicillin resistance genes were not detected in culture-based or metagenomic analyses. Camphylobacteriaceae were significantly more abundant in the cloacal samples, especially in enrofloxacin-treated chickens, where a metagenome-assembled C. jejuni genome harboring fluoroquinolone and β-lactam resistance genes was identified.

CONCLUSIONS

Within a "farm-to-fork, one health" perspective, considering the evidence that bacitracin and enrofloxacin used in poultry production can select for resistance, we recommend their use be regulated. Furthermore, we suggest routine surveillance of ESBL E. coli, vancomycin-resistant E. faecalis and E. faecium, and fluoroquinolone-resistant C. jejuni strains considering their pathogenic nature and capacity to disseminate AMR to the environment. Video Abstract.

Dietary encapsulated Bifidobacterium animalis and Agave fructans improve growth performance, health parameters, and immune response in broiler chickens

Objective

The present study was conducted to evaluate the effects of dietary supplementation with Bifidobacterium animalis, Agave fructans, and symbiotic of both encapsulated on growth performance, feed efficiency, blood parameters, and immune status in broiler chickens, and to compare these with diets including antibiotic growth promoters and without additives.

Methods

A comparative experimental study was carried out with 135 male Ross 308 broiler chickens. Each trial was divided into 5 equal groups. Control group (CON) received a standard diet without growth promoter; GPA: a standard diet with colistin sulfate and zinc bacitracin (0.25 g/kg of feed); PRE: a standard diet with 1% Agave fructans; PRO: a standard diet with Bifidobacterium animalis (11.14±0.70 log CFU/g); SYM: a standard diet with B. animalis and Agave fructans.

Results

A significant decrease in food consumption was found for the GPA, PRE, and SYM, compared to the CON group. The results show a better feed conversion index in PRE and GPA with respect to the CON group with the highest conversion index. Interestingly, the weight of the gastrointestinal tract shows a statistically significant difference between GPA and PRE groups. Moreover, the length of the gastrointestinal tract of the GPA group was less than the PRE group. In the total leukocyte count, there was a statistically significant increase in the GPA group compared to the CON, PRE, and PRO groups, and the H:L index was lower in PRO. Regarding the cytokines, IL-10 decreased in PRO compared to CON and PRE, while IL-1β increased in the SYM group.

Conclusion

Alternative treatments were shown to achieve similar productive results as growth-promoting antibiotics and showed improvement over diet without additives; however, they have immunomodulatory properties and improved the development of the gastrointestinal tract compared to the treatment of growth-promoting antibiotics.

Phage and phage lysins: New era of bio-preservatives and food safety agents

There has been an increase in the search and application of new antimicrobial agents as alternatives to use of chemical preservatives and antibiotic-like compounds by the food industry. The massive use of antibiotic has created a reservoir of antibiotic-resistant bacteria that find their way from farm to humans. Thus, there exists an imperative need to explore new antibacterial options and bacteriophages perfectly fit into the class of safe and potent antimicrobials. Phage bio-control has come a long way owing to advances with use of phage cocktails, recombinant phages, and phage lysins; however, there still exists unmet challenges that restrict the number of phage-based products reaching the market. Hence, further studies are required to explore for more efficient phage-based bio-control strategies that can become an integral part of food safety protocols. This review thus aims to highlight the recent developments made in the application of phages and phage enzymes covering pre-harvest as well as post-harvest usage. It further focuses on the major issues in both phage and phage lysin research hindering their optimum use while detailing out the advances made by researchers lately in this direction for full exploitation of phages and phage lysins in the food sector.

Antibacterial Potential of Biosynthesized Zinc Oxide Nanoparticles against Poultry-Associated Foodborne Pathogens: An In Vitro Study

Simple Summary

The overuse of antibiotics in the poultry industry has led to the emergence of multidrug-resistant microorganisms. Thus, there is a need to find an alternative to conventional antibiotics. Recently, zinc oxide nanoparticles (ZnO NPs) have gained much attention due to their excellent antibacterial activity. In addition, ZnO NPs is an essential trace mineral in poultry diets. In this sense, incorporating ZnO NPs into poultry can promote growth and performance while serving as an alternative antibacterial agent to control diseases. Therefore, this study aimed to assess the in vitro antibacterial activity and antibacterial mechanisms of ZnO NPs against poultry-associated foodborne pathogens (Salmonella spp., Escherichia coli, and Staphylococcus aureus). The obtained findings demonstrated effective antibacterial actions against the tested microorganisms. The nanotechnology approach could represent a new tool for combating pathogens in the poultry industry.

Abstract

Since the emergence of multidrug-resistant bacteria in the poultry industry is currently a serious threat, there is an urgent need to develop a more efficient and alternative antibacterial substance. Zinc oxide nanoparticles (ZnO NPs) have exhibited antibacterial efficacy against a wide range of microorganisms. Although the in vitro antibacterial activity of ZnO NPs has been studied, little is known about the antibacterial mechanisms of ZnO NPs against poultry-associated foodborne pathogens. In the present study, ZnO NPs were successfully synthesized using Lactobacillus plantarum TA4, characterized, and their antibacterial potential against common avian pathogens (Salmonella spp., Escherichia coli, and Staphylococcus aureus) was investigated. Confirmation of ZnO NPs by UV-Visual spectroscopy showed an absorption band center at 360 nm. Morphologically, the synthesized ZnO NPs were oval with an average particle size of 29.7 nm. Based on the dissolution study of Zn²⁺, ZnO NPs released more ions than their bulk counterparts. Results from the agar well diffusion assay indicated that ZnO NPs effectively inhibited the growth of the three poultry-associated foodborne pathogens. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were assessed using various concentrations of ZnO NPs, which resulted in excellent antibacterial activity as compared to their bulkier counterparts. S. aureus was more susceptible to ZnO NPs compared to the other tested bacteria. Furthermore, the ZnO NPs demonstrated substantial biofilm inhibition and eradication. The formation of reactive oxygen species (ROS) and cellular material leakage was quantified to determine the underlying antibacterial mechanisms, whereas a scanning electron microscope (SEM) was used to examine the morphological changes of tested bacteria treated with ZnO NPs. The findings suggested that ROS-induced oxidative stress caused membrane damage and bacterial cell death. Overall, the results demonstrated that ZnO NPs could be developed as an alternative antibiotic in poultry production and revealed new possibilities in combating pathogenic microorganisms.

Cinnamon: A Natural Feed Additive for Poultry Health and Production-A Review

The increased bacterial resistance to synthetic antibiotics and consumer awareness about the health and food safety concerns have triggered the ban on the use of antibiotic growth promotors (AGPs) in the poultry industry. This situation encouraged the poultry sector and industry to explore safe alternatives to AGPs and focus on developing more sustainable feed management strategies to improve the intestinal health and growth performance of poultry. Consequently, phytogenic feed additives (PFAs) have emerged as natural alternatives to AGPs and have great potential in the poultry industry. In recent years, cinnamon (one of the most widely used spices) has attracted attention from researchers as a natural product with numerous health benefits for poultry. The essential oils in cinnamon, in particular, are of interest because of their antioxidant, anti-microbial, anti-inflammatory, antifungal, and hypocholesterolaemic effects, in addition to their ability to stimulate digestive enzymes in the gut. This review mainly emphasizes the potential impact of cinnamon as a natural feed additive on overall gut health, nutrient digestibility, blood biochemical profile, gene expression, gut microbiota and immune response.

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.

Effects of Bacillus subtilis and Bacillus licheniformis on growth performance, immunity, short chain fatty acid production, antioxidant capacity, and cecal microflora in broilers

This study investigated the effects of dietary supplementation with Bacillus subtilis (B. subtilis) or Bacillus licheniformis (B. licheniformis) on growth performance, immunity, antioxidant capacity, short chain fatty acid (SCFA) production, and the cecal microflora in broiler chickens. In total, 360 male, 1-day-old Cobb 500 birds were randomly divided into 3 groups: the control group was fed a basal diet; the B. subtilis group was fed a basal diet supplemented with 1.5 × 10⁹ CFU/kg B. subtilis; the B. licheniformis group was fed a basal diet supplemented with 1.5 × 10⁹ CFU/kg B. licheniformis. Results showed that chickens supplemented with either B. subtilis or B. licheniformis had comparatively higher (P < 0.05) body weight and average daily gain, whereas no difference (P > 0.05) was observed in feed efficiency. Concentrations of serum IgA, IgY, and IgM, as well as anti-inflammatory IL-10 were significantly increased (P < 0.05), and proinflammatory IL-1β and IL-6 were significantly decreased (P < 0.05) by B. subtilis or B. licheniformis supplementation. Moreover, chickens fed with diets supplemented by either B. subtilis or B. licheniformis had greater antioxidant capacity, indicated by the notable increases (P < 0.05) in glutathione peroxidase, superoxide dismutase, and catalase, along with decrease (P < 0.05) in malondialdehyde. Compared to the control group, levels of SCFA, excluding acetic and propionic acid, in cecal content had improved (P < 0.05) by adding B. licheniformis, and significant increase (P < 0.05) in acetic and butyric acid was observed with B. subtilis supplementation. Microbial analysis showed that both B. subtilis or B. licheniformis supplementation could increase butyrate-producing bacteria such as Alistipes and Butyricicoccus, and decrease pathogenic bacteria such as the Synergistetes and Gammaproteobacteria. In summary, dietary supplemented with B. subtilis or B. licheniformis improved growth performance, immune status, and antioxidant capacity, increased SCFA production, and modulated cecal microbiota in chickens. Moreover, B. licheniformis was more effective than B. subtilis with the same supplemental amount.

Promising Role of Growth Hormone-Boosting Peptide in Regulating the Expression of Muscle-Specific Genes and Related MicroRNAs in Broiler Chickens

Appropriate skeletal muscle development in poultry is positively related to increasing its meat production. Synthetic peptides with growth hormone-boosting properties can intensify the effects of endogenous growth hormones. However, their effects on the mRNA and miRNA expression profiles that control muscle development post-hatching in broiler chicks is unclear. Thus, we evaluated the possible effects of synthetic growth hormone-boosting peptide (GHBP) inclusion on a chicken's growth rate, skeletal muscle development-related genes and myomiRs, serum biochemical parameters, and myofiber characteristics. A total of 400 one-day-old broiler chicks were divided into four groups supplied with GHBP at the levels of 0, 100, 200 and 300 μg/kg for 7 days post-hatching. The results showed that the highest levels of serum IGF-1 and GH at d 20 and d 38 post-hatching were found in the 200 μg/kg GHBP group. Targeted gene expression analysis in skeletal muscle revealed that the GHBP effect was more prominent at d 20 post-hatching. The maximum muscle development in the 200 μg/kg GHBP group was fostered by the upregulation of IGF-1, mTOR, myoD, and myogenin and the downregulation of myostatin and the Pax-3 and -7 genes compared to the control group. In parallel, muscle-specific myomiR analysis described upregulation of miR-27b and miR-499 and down-regulation of miR-1a, miR-133a, miR-133b, and miR-206 in both the 200 and 300 μg/kg GHBP groups. This was reflected in the weight gain of birds, which was increased by 17.3 and 11.2% in the 200 and 300 μg/kg GHBP groups, respectively, when compared with the control group. Moreover, the maximum improvement in the feed conversion ratio was achieved in the 200 μg/kg GHBP group. The myogenic effects of GHBP were also confirmed via studying myofiber characteristics, wherein the largest myofiber sizes and areas were achieved in the 200 μg/kg GHBP group. Overall, our findings indicated that administration of 200 μg/kg GHBP for broiler chicks could accelerate their muscle development by positively regulating muscle-specific mRNA and myomiR expression and reinforcing myofiber growth.

Scale-up production of and dietary supplementation with the recombinant antimicrobial peptide tilapia piscidin 4 to improve growth performance in Gallus gallus domesticus

Antimicrobial peptides (AMPs) are short and positively charged peptides with broad-spectrum antimicrobial activities. AMPs have been investigated as potential antibiotic alternatives to improve growth performance and prevent pathogen infection in the poultry industry. The antimicrobial peptide tilapia piscidin 4 (TP4) was derived from Oreochromis niloticus, possesses antimicrobial activities and immunomodulatory properties, promotes intestinal health, and protects against pathogen infection. The codon-optimized sequence of TP4 was introduced into the pPICZαA vector and transformed into Pichia pastoris. Large-scale expression was induced following culture with methanol in a 500-liter fermenter. Freeze drying of fermented rTP4 broth and then rTP4 evaluation as a feed additive for Gallus gallus domesticus were performed. The in vitro antimicrobial activity of recombinant TP4 (rTP4) against gram-positive and gram-negative pathogens was evaluated. Evaluation of the effect of temperature on the antimicrobial activity of rTP4 showed its high stability at high temperatures. rTP4 significantly enhanced the phagocytic activity of macrophage cells, indicating that rTP4 has a remarkable ability to stimulate macrophages. rTP4 was used as a dietary supplement at 0.75, 1.5, 3.0, 6.0 and 12% in G. g. domesticus for five weeks, and growth performance, gut microbiota composition, and histology were assessed. The 3.0% rTP4 supplement group showed a significant increase in weight gain ratio and feed efficiency compared to those of the basal broiler diet group. Crude rTP4 was expressed by yeast to significantly promote growth efficiency and resistance against pathogens in G. g. domesticus, which could indicate its use as a suitable alternative to antibiotics as feed additives in the poultry industry.

Effect of yeast cell wall supplementation on intestinal integrity, digestive enzyme activity and immune traits of broilers

1. The protective layer formed by intestinal epithelial cells acts as a barrier preventing the adhesion of pathogenic bacteria, aids digestion and passage of nutrients and reduces damage caused from toxins on the gastrointestinal tract. This study was conducted to investigate the effects of a yeast cell wall-based product (YCW), on broiler intestinal integrity, digestive enzyme capacity and immune function.2. A 35-d trial involving 246, one-d-of-hatch male broiler chickens was carried out at a trial facility at Agri-Food Biosciences Institute (AFBI, Belfast, UK). Birds were randomly allocated into 6 pens at day of hatch (41 birds/pen; 123 birds/group). Pens were divided into two groups: (1) basal diet and (2) basal diet that incorporated YCW at the manufacturers' recommended inclusion levels (Alltech Inc., Lexington, Kentucky, USA).3. In this study, YCW supplementation affected broiler intestinal morphology resulting in greater crypt depth, villus height and surface area, goblet cell density and mucus layer thickness and lower muscularis mucosae thickness. The digestive enzymes, maltase, sucrase and alkaline phosphatase, were significantly higher in the YCW supplemented group compared to the control. The expression levels of pro-inflammatory cytokines, IL-1β, IL-12 and IL-18, were significantly lower as was necroptotic cell death in YCW supplemented birds.4. In conclusion, under the conditions of this study, YCW supplementation positively affected intestinal health parameters in broilers following 35-d supplementation.

Probiotics: an Antibiotic Replacement Strategy for Healthy Broilers and Productive Rearing

Pathogens develop resistance to antibiotics at a rate much faster than the discovery of new antimicrobial compounds. Reports of multidrug-resistant bacteria isolated from broilers, and the possibility that these strains may spread diseases amongst humans, prompted many European countries to ban the inclusion of antibiotics in feed. Probiotics added to broiler feed controlled a number of bacterial infections. A combination of Enterococcus faecium, Pediococcus acidilactici, Bacillus animalis, Lactobacillus salivarius and Lactobacillus reuteri decreased the colonisation of Campylobacter jejuni and Salmonella Enteritidis in the gastro-intestinal tract (GIT) of broilers, whereas Bacillus subtilis improved feed conversion, intestinal morphology, stimulated the immune system and inhibited the colonisation of Campylobacter jejuni, Escherichia coli and Salmonella Minnesota. Lactobacillus salivarius and Pediococcus parvulus improved weight gain, bone characteristics, intestinal morphology and immune response, and decreased the colonisation of S. Enteritidis. Lactobacillus crispatus, L. salivarius, Lactobacillus gallinarum, Lactobacillus johnsonii, Enterococcus faecalis and Bacillus amyloliquefaciens decreased the Salmonella count and led to an increase in lysozyme and T lymphocytes. Probiotics may also improve feed digestion through production of phytases, lipases, amylases and proteases or stimulate the GIT to secrete digestive enzymes. Some strains increase the nutritional value of feed by production of vitamins, exopolysaccharides and antioxidants. Bacteriocins, if produced, regulate pathogen numbers in the GIT and keep pro-inflammatory and anti-inflammatory reactions in balance.

Effect of dietary tannins on the performance, lymphoid organ weight, and amino acid ileal digestibility of broiler chickens: A meta-analysis

Background and Aim:

Tannins are functional secondary metabolites that may provide benefits to ruminants. However, to date, their effects on broiler chickens remain inconclusive. This study aimed to evaluate the effectiveness of dietary tannin levels on the performance, body organs, and amino acid (AA) digestibility of broiler chickens using a meta-analysis.

Materials and Methods:

After verification and evaluation, a total of 22 articles were included in the present study. All data regarding dietary tannin dosages, performance, digestibility, and gastrointestinal physiology of broiler chickens were tabulated into a database. The database data were then statistically analyzed using mixed models, with tannin dose as a fixed effect and study as a random effect.

Results:

High levels of dietary tannins negatively affected the average daily gain and average daily feed intake of broiler chickens according to linear patterns (p<0.001). In addition, dietary tannins decreased drumstick and liver weights, as well as bursa of Fabricius and spleen weight (p<0.05). Meanwhile, other carcass traits (i.e., thigh, wings, and body fat) were not influenced by dietary tannins. Regarding AA digestibility, high dietary tannin concentrations induced negative responses on isoleucine, leucine, and methionine digestibility (p<0.05).

Conclusion:

Dietary tannins appear to have a negative effect on broiler performance, lymphoid organ weight, and AA ileal digestibility. Hence, the addition of tannins to broiler diets is not recommended.

Diversity of the Tellurite Resistance Gene Operon in Escherichia coli

Tellurite is highly toxic to most bacteria owing to its strong oxidative ability. However, some bacteria demonstrate tellurite resistance. In particular, some Escherichia coli strains, including Shiga toxin-producing E. coli O157:H7, are known to be resistant to tellurite. This resistance is involved in ter operon, which is usually located on a prophage-like element of the chromosome. The characteristics of the ter operon have been investigated mainly by genome analysis of pathogenic E. coli; however, the distribution and structural characteristics of the ter operon in other E. coli are almost unknown. To clarify these points, we examined 106 E. coli strains carrying the ter operon from various animals. The draft genomes of 34 representative strains revealed that ter operons were clearly classified into four subtypes, ter-type 1–4, at the nucleotide sequence level. Complete genomic sequences revealed that operons belonging to three ter-types (1, 3, and 4) were located on the prophage-like elements on the chromosome, whereas the ter-type 2 operon was located on the IncHI2 plasmid. The positions of the tRNA^Ser, tRNA^Met, and tRNA^Phe indicated the insertion sites of elements carrying the ter operons. Using the PCR method developed in this study, 106 strains were classified as type 1 (n = 66), 2 (n = 13), 3 (n = 8), and 4 (n = 17), and two strains carried both types 1 and 2. Furthermore, significant differences in the minimum inhibitory concentration (MIC) of tellurite were observed between strains carrying ter-type 4 and the others (p < 0.05). The ter-type was also closely related to the isolation source, with types 2 and 4 associated with chickens and deer, respectively. This study provided new insights related not only to genetic characteristics of the ter operons, but also to phenotypic and ecological characteristics that may be related to the diversity of the operon.

Chemical Contamination Pathways and the Food Safety Implications along the Various Stages of Food Production: A Review

Historically, chemicals exceeding maximum allowable exposure levels have been disastrous to underdeveloped countries. The global food industry is primarily affected by toxic chemical substances because of natural and anthropogenic factors. Food safety is therefore threatened due to contamination by chemicals throughout the various stages of food production. Persistent Organic Pollutants (POPs) in the form of pesticides and other chemical substances such as Polychlorinated Biphenyls (PCBs) have a widely documented negative impact due to their long-lasting effect on the environment. This present review focuses on the chemical contamination pathways along the various stages of food production until the food reaches the consumer. The contamination of food can stem from various sources such as the agricultural sector and pollution from industrialized regions through the air, water, and soil. Therefore, it is imperative to control the application of chemicals during food packaging, the application of pesticides, and antibiotics in the food industry to prevent undesired residues on foodstuffs. Ultimately, the protection of consumers from food-related chemical toxicity depends on stringent efforts from regulatory authorities both in developed and underdeveloped nations.

Bacillus subtilis-Based Probiotic Improves Skeletal Health and Immunity in Broiler Chickens Exposed to Heat Stress

Simple Summary

High ambient temperature is a major environmental stressor affecting the physiological and behavioral status of animals, increasing stress susceptibility and immunosuppression, and consequently increasing intestinal permeability (leaky gut) and related neuroinflammation. Probiotics, as well as prebiotics and synbiotics, have been used to prevent or decrease stress-associated detrimental effects on physiological and behavioral homeostasis in humans and various animals. The current data indicate that a dietary probiotic supplement, Bacillus subtilis, reduces heat stress-induced abnormal behaviors and negative effects on skeletal health in broilers through a variety of cellular responses, regulating the functioning of the microbiota–gut–brain axis and/or microbiota-modulated immunity during bone remodeling under thermoneutral and heat-stressed conditions.

Abstract

The elevation of ambient temperature beyond the thermoneutral zone leads to heat stress, which is a growing health and welfare issue for homeothermic animals aiming to maintain relatively constant reproducibility and survivability. Particularly, global warming over the past decades has resulted in more hot days with more intense, frequent, and long-lasting heat waves, resulting in a global surge in animals suffering from heat stress. Heat stress causes pathophysiological changes in animals, increasing stress sensitivity and immunosuppression, consequently leading to increased intestinal permeability (leaky gut) and related neuroinflammation. Probiotics, as well as prebiotics and synbiotics, have been used to prevent or reduce stress-induced negative effects on physiological and behavioral homeostasis in humans and various animals. The current data indicate dietary supplementation with a Bacillus subtilis-based probiotic has similar functions in poultry. This review highlights the recent findings on the effects of the probiotic Bacillus subtilis on skeletal health of broiler chickens exposed to heat stress. It provides insights to aid in the development of practical strategies for improving health and performance in poultry.

Dietary effect of licorice (Glycyrrhiza glabra) on quail performance, carcass, blood metabolites and intestinal microbiota

This study aimed to assess the impacts of licorice (Glycyrrhiza glabra) on the growth performance, carcass traits, intestinal microbiota, liver and kidney functions, immunity, oxidative status, and lipid profile of Japanese quails. A total of 200 one-week-old unsexed Japanese quails with an average initial body weight of 26.24 ± 0.2 g were randomly distributed into 5 equal groups of 40 birds and further subdivided into 5 replicates. The first (control) group was fed a diet without any licorice, while licorice powder was added at levels of 250, 500, 750, and 1000 mg per kg diet in the second, third, fourth, and fifth groups, respectively. At the age of 3 wk, the group of quail fed on a diet supplemented with 750 and 1000 mg licorice/kg of diet gained the highest body weight (BW) and daily body weight (DBW), while attaining the lowest feed conversion ratio (FCR) compared to other groups. Meanwhile, groups fed diets with licorice at levels of 0 and 250 mg/kg showed the highest feed intake. After the 5-wk feeding trial, the highest BW and DBW values, and the lowest FCR were recorded in the group fed with 750 mg licorice/kg diet. The different treatments produced no significant differences (P > 0.05) in quail carcass characteristics, including percentages of carcass, liver, gizzard, heart, giblets, and dressing. The blood of the group fed a 750 mg licorice diet had higher contents of total protein and GLOB, while its contents of A/G%, lactate dehydrogenase (LDH), total cholesterol, triglyceride (TG), and low density lipoprotein (LDL) were lower. Apart from the high level of licorice (1000 mg/kg), the MDA level was linearly and quadratically (P = 0.0413 and 0.001) decreased with different licorice groups, while superoxide dismutase (SOD), total antioxidant capacity (TAC), immunoglobulin G (IgG), and M (IgM) were quadratically increased when compared to the control group. Licorice supplementation resulted in marked reductions in the number of total bacteria, coliforms, E. coli, and Salmonella, compared to those in the control. In conclusion, the inclusion of licorice at levels of 750 and 1000 mg/kg into the diet of Japanese quail enhances the animal's performance, immunity, antioxidant capacity, and maintains a healthy gut microbiota.

Are There Effective Intervention Measures in Broiler Production against the ESBL/AmpC Producer Escherichia coli?

Extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase (AmpC) producing Enterobacteriaceae occur frequently in livestock animals and the subsequent stages of the meat production chain and are therefore considered a risk for human health. Strict biosecurity measures and optimal farm management should reduce or even prevent poultry flock colonization at farm level. This review summarizes and evaluates published information on the effectiveness of specific intervention measures and farm management factors aiming to reduce the occurrence and spread of ESBL/AmpC producing or commensal or pathogenic E. coli in broiler chicken farms. In this systematic literature review, a total of 643 publications were analyzed, and 14 studies with significant outcome about the effectiveness of specific measures against E. coli and ESBL/AmpC producing E. coli in broiler chicken farms were found. Different feed additives seem to have an impact on the occurrence of those microorganisms. The measures ‘cleaning and disinfection’ and ‘competitive exclusion’ showed strong effects in prevention in some studies. In summary, some intervention measures showed potential to protect against or eliminate ESBL/AmpC-producing, commensal or pathogenic E. coli at farm level. Due to the high variability in the outcome of the studies, more specific, detailed investigations are needed to assess the potential of the individual intervention measures.

Detection of Antimicrobial Residues in Poultry Litter: Monitoring a Risk through a Selective and Sensitive HPLC-MS/MS Method

Simple Summary

After administration of antimicrobials, poultry excrete significant concentrations of antimicrobials through their droppings, which accumulate in the litter where poultry are housed. Poultry litter, which consists mainly of wood shavings, feathers, and droppings, is widely used as an agricultural fertilizer worldwide. The period that antimicrobials persist in agricultural soils could present various environmental and public health concerns. Thus, in this research, a method to identify different families of antimicrobials in poultry litter was developed. Results show that HPLC–MS/MS can reliably detect nine different compounds from three families of antimicrobials. This method was used to identify antimicrobials from commercial poultry flocks, providing a valuable and specific tool to monitor these residues in poultry litter prior to its use as an agricultural fertilizer.

Abstract

Tetracyclines, sulphonamides, and quinolones are families of antimicrobials (AMs) widely used in the poultry industry and can excrete up to 90% of AMs administrated, which accumulate in poultry litter. Worryingly, poultry litter is widely used as an agriculture fertilizer, contributing to the spread AMs residues in the environment. The aim of this research was to develop a method that could simultaneously identify and quantify three AMs families in poultry litter by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Samples of AMs free poultry litter were used to validate the method according to 657/2002/EC and VICH GL49. Results indicate that limit of detection (LOD) ranged from 8.95 to 20.86 μg kg⁻¹, while limits of quantitation (LOQ) values were between 26.85 and 62.58 µg kg⁻¹ of tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, enrofloxacin, ciprofloxacin, flumequine, sulfachloropyridazine, and sulfadiazine. Recoveries obtained ranged from 93 to 108%. The analysis of field samples obtained from seven commercial poultry flocks confirmed the adequacy of the method since it detected means concentrations ranging from 20 to 10,364 μg kg⁻¹. This provides us an accurate and reliable tool to monitor AMs residues in poultry litter and control its use as agricultural fertilizer.

Effects of essential oil on growth performance, digestibility, immunity, and intestinal health in broilers

Essential oils (EO) are concentrated hydrophobic liquids containing volatile aromatic compounds obtained from plants, which have properties as withdrawn antibiotic growth promoters. The objective of this study was to explore the effects of EO on growth performance, digestibility, immunity and intestinal health in broilers. A total of 500 1-day-old Arbor Acre broilers were randomly put into five groups with 10 replicate cages containing 10 birds each. Birds in the 5 groups were fed a basal diet (CON), and basal diet with 50, 100, 200 or 400 mg/kg EO (EO0.5, EO1, EO2 and EO4) for 42 d respectively. Birds were euthanized at 21d and 42 d, blood and tissue samples were collected. In the study, the digestibility of DM, GE and EE in groups with EO supplementation were significantly increased compared with CON group (P < 0.05). However, only EO2 and EO4 significantly increased the digestibility of CP compared with CON group (P < 0.05). In contrast to CON group, EO0.5 and EO1 in jejunum at 21 d, and EO1 in jejunum at 42 d markedly increased the activity of sucrase (P < 0.05). In addition, the level of SOD of EO2 and EO4 in serum at 21 d was significantly increased compared with CON group (P < 0.05). What's more, the concentration of intestinal mucosa SIgA in jejunum and ileum at 21 d of groups with EO supplementation was significantly increased compared with CON group (P < 0.05). Moreover, V/C in jejunum at 21 d of groups with EO supplementation, CD in jejunum at 42 d was also significantly increased to compare with CON group (P < 0.05). Furthermore, the expression levels of critical genes associated with nutrient transportation (i.e., GLUT2, SGLT1, SLC38A, SLC79A and SLC27A4) and barrier function (TJP1) were quadratically and linearly up-regulated in jejunum and ileum with EO supplementation (P < 0.05). These results suggest that EO has a positive impact on growth, immunity and intestinal health in broilers, and 200 mg/kg of EO was recommended in broiler diet.

Effects of Dietary Inclusion of Dry Hydrastis canadensis on Laying Performance, Egg Quality, Serum Biochemical Parameters and Cecal Microbiota in Laying Hens

Simple Summary

Extensive studies on alternative sources of feed additives to replace antibiotics are required. Plants of the Ranunculaceae family have been used as medicines or dyes. The representative plant is goldenseal (Hydrastis canadensis), which has a long history of use in North America, with berberine considered the most effective ingredient in goldenseal. Some natural compounds in Hydrastis canadensis function as efflux pump inhibitors and thus may have bactericidal effects against pathogens with antibiotic resistance. However, no conclusive beneficial effects of goldenseal on the livestock industry have been reported. The objective of this study was to examine whether the alternative use of goldenseal roots or leaves has potential health benefits in chickens. Our data demonstrate that Hydrastis canadensis can improve the egg quality and modulate the microbiota composition of laying hens.

Abstract

Alternative growth promoters are able to not only effectively replace the traditional use of antibiotics but also provide additional health benefits for livestock and reduce food safety concerns. This study investigated the effects of dry Hydrastis canadensis on the laying performance and fecal microbial community of laying hens. Twenty-four Lohmann (LSL, white layer strain) hens were reared from 40 to 48 weeks of age and randomly allotted to four dietary treatments (six birds/treatment). The dietary treatments comprised a basal diet with no treatment as control, a basal diet plus 0.6% powder of dry Hydrastis canadensis roots (R) or leaves (L), and a basal diet plus 0.6% powder of a mixture of dry Hydrastis canadensis roots and leaves (1:1, LR). No mortality was observed in the whole experimental period. The results indicated that albumen height in the LR group was significantly greater than that in the control group. The diet supplemented with Hydrastis canadensis had no significant effects on egg production rate, egg weight, eggshell strength, eggshell thickness, Haugh unit, or yolk height during the whole experimental phase. However, principal coordinate analysis, comparative heat map analysis, and cluster dendrogram analysis of cecal microbiota showed distinct clusters among the groups treated with Hydrastis canadensis and the control group. Regarding blood biochemical parameters, serum cholesterol levels were significantly lower in all Hydrastis canadensis-treated groups compared with those in the control group. Moreover, serum low-density lipoprotein levels were lower in hens supplemented with the leaf of Hydrastis canadensis. The abundances of the phyla Fusobacteria and Kiritimatiellaeota were increased (p < 0.05) in laying hens fed with 0.6% Hydrastis canadensis leaves, whereas the abundance of the phylum Firmicutes in cecum digesta decreased in response to treatment with Hydrastis canadensis roots and leaves. The relative abundance of the Fusobacterium genus was higher in the LR group compared with that in the control. On the contrary, we found a different trend in the Synergistes genus. The potential influences of these microbiota on the performance of laying hens were discussed. The results demonstrate that Hydrastis canadensis can improve the egg albumen height and modulate the cecum digesta microbiota composition of laying hens.

Extract of neem (Azadirachta indica) leaf exhibits bactericidal effect against multidrug resistant pathogenic bacteria of poultry

The aim of the study was to determine the efficacy of neem leaf extract against multidrug resistant (MDR) pathogenic bacteria. Laboratory stock culture of Pasteurella multocida, Salmonella pullorum, Salmonella gallinarum and Escherichia coli was revived. Antibiogram profiles of these bacteria were determined by disc diffusion method. Ethanolic extract of neem leaf was prepared. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of neem leaf extract (112.5, 100, 50, 25, 12.5, 6.25 and 3.12 mg/ml) against MDR pathogenic bacteria of poultry were determined by double dilution method. The MIC and MBC of the neem leaf extract were 12.5 and 25 mg/ml, respectively for P. multocida, 50 and 100 mg/ml for S. pullorum and S. gallinarum, 100 and 112.5 mg/ml for E. coli. Neem leaf extracts exhibited bactericidal effect against MDR pathogenic bacteria of poultry.

Impact of Xylanase and Glucanase on Oligosaccharide Formation, Carbohydrate Fermentation Patterns, and Nutrient Utilization in the Gastrointestinal Tract of Broilers

This study aimed at determining how the degradation of cereal non-starch polysaccharides (NSP) by dietary enzymes during feed digestion can influence nutrient digestibility and NSP fermentability in broilers. Ninety-six one-day-old male broilers were assigned to 4 different treatments: control and enzyme-supplemented wheat-based (WC, WE) or maize-based (MC, ME) treatments. Enzyme supplementation with endo-xylanase and endo-glucanase occurred from day 20 onwards. On day 28, digesta samples were collected. Nutrient digestibility, NSP recovery, oligosaccharide profile, and short-chain fatty acids (SCFA) content were determined. Enzyme supplementation in WE resulted in a higher starch (3%; p = 0.004) and protein (5%; p = 0.002) digestion in the ileum compared to WC. Xylanase activity in WE led to in situ formations of arabinoxylan-oligosaccharides consisting of 5 to 26 pentose units in the ileum. This coincided with decreased arabinose (p = 0.059) and xylose (p = 0.036) amounts in the ceca and higher acetate (p = 0.014) and butyrate (p = 0.044) formation in WE compared to WC. Conversely, complete total tract recovery of arabinoxylan in MC and ME suggested poor maize NSP fermentability. Overall, enzyme action improved nutrient digestibility and arabinoxylan fermentability in the wheat-based diet. The lower response of the maize-based diet to enzyme treatment may be related to the recalcitrance of maize arabinoxylan as well as to the high nutritive value of maize.

Acute toxicity of piggery effluent and veterinary pharmaceutical cocktail on freshwater organisms

Intensive livestock farming has increased the use of veterinary pharmaceuticals in many developing countries, and this is considered a significant concern to the freshwater ecosystem. However, the information on the potential acute toxicity of piggery effluent waste and the veterinary pharmaceutical effluent discharged into the aquatic environment is limited. This study assessed the adverse effect of a piggery effluent and the cocktail mixtures of high- and low-level doses of three frequently occurring veterinary pharmaceuticals (tetracycline (TETR), ivermectin (IVER), and salicylic acid (SALA)) on freshwater organisms using three representative freshwater biotests organisms: Pseudokirchneriella subcapitata (P. subcapitata), Daphnia magna (D. magna), and Tetrahymena thermophila (T. thermophila). The freshwater organism test results showed that the 24-h and 48-h EC₅₀ algal toxicity to P. subcapitata exposed to 10% unfiltered piggery effluent were 25.6 and 49.3% respectively while the 24-h LC₅₀ value to Cladocera, D. magna exposed to unfiltered piggery effluent was 23.2 (17.7-30.4)%. The 24-h EC₅₀ protozoan toxicity to T. thermophila exposed to 1% HLD veterinary pharmaceuticals was 0.014 μg/L. Thus, the study established the different sensitivities of freshwater organisms to various percentage levels of piggery effluent and high- and low-level doses of veterinary pharmaceutical. The piggery effluent and the pharmaceutical cocktail mixtures have potential toxicological effects on the freshwater ecosystem.

Alternatives to Antibiotics: A Symposium on the Challenges and Solutions for Animal Health and Production

Antibiotics have improved the length and quality of life of people worldwide and have had an immeasurable influence on agricultural animal health and the efficiency of animal production over the last 60 years. The increased affordability of animal protein for a greater proportion of the global population, in which antibiotic use has played a crucial part, has resulted in a substantial improvement in human quality of life. However, these benefits have come with major unintended consequences, including antibiotic resistance. Despite the inherent benefits of restricting antibiotic use in animal production, antibiotics remain essential to ensuring animal health, necessitating the development of novel approaches to replace the prophylactic and growth-promoting benefits of antibiotics. The third International Symposium on “Alternatives to Antibiotics: Challenges and Solutions in Animal Health and Production” in Bangkok, Thailand was organized by the USDA Agricultural Research Service, Faculty of Veterinary Science, Chulalongkorn University and Department of Livestock Development-Thailand Ministry of Agriculture and Cooperative; supported by OIE World Organization for Animal Health; and attended by more than 500 scientists from academia, industry, and government from 32 nations across 6 continents. The focus of the symposium was on ensuring human and animal health, food safety, and improving food animal production efficiency as well as quality. Attendees explored six subject areas in detail through scientific presentations and panel discussions with experts, and the major conclusions were as follows: (1) defining the mechanisms of action of antibiotic alternatives is paramount to enable their effective use, whether they are used for prevention, treatment, or to enhance health and production; (2) there is a need to integrate nutrition, health, and disease research, and host genetics needs to be considered in this regard; (3) a combination of alternatives to antibiotics may need to be considered to achieve optimum health and disease management in different animal production systems; (4) hypothesis-driven field trials with proper controls are needed to validate the safety, efficacy, and return of investment (ROI) of antibiotic alternatives.

Potential role of important nutraceuticals in poultry performance and health - A comprehensive review

Antibiotics use in poultry as a growth promoter leads to the propagation of antibiotic-resistant microorganisms and incorporation of drug residues in foods; therefore, it has been restricted in different countries. There is a global trend to limit the use of antibiotics in the animal products. Prevention of the antibiotics use in the poultry diets led to the reduction in the growth performance. Consequently, there is a high demand for natural substances that lead to the same growth enhancement and beneficially affect poultry health. These constituents play essential roles in regulating the normal physiological functions of animals including the protection from infectious ailments. Nutraceuticals administration resulted beneficial in both infectious and noninfectious diseases. Being the natural components of diet, they are compatible with it and do not pose risks associated with antibiotics or other drugs. Nutraceuticals are categorized as commercial additives obtained from natural products as an alternative feed supplement for the improvement of animal welfare. This group includes enzymes, synbiotics, phytobiotics, organic acids and polyunsaturated fatty acids. In the present review, the summary of various bioactive ingredients that act as nutraceuticals and their mode of action in growth promotion and elevation of the immune system has been presented.

Effect of Lactobacillus Species Probiotics on Growth Performance of Dual-Purpose Chicken

Introduction

In-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry due to the ever-growing strict prohibitions on antibiotic growth promoters (AGP) in animal production.

Methods

The study was conducted to investigate the effects of Lactobacillus paracaseis sparacasei and Lactobacillus rhamnosus on the growth performance of 120 day-olds randomly selected Sasso dual-purpose chicken. They were divided into four groups with two replicates per group and 15 chicks per replicate. The treatments were T₁ (control), T₂ (supplement diet with 4g probiotic), T₃ (supplement diet with 2g probiotic), T₄ (supplement diet with 1g probiotic). The experimental feeding trials were conducted after two weeks adaptation period.

Results

The present findings revealed that the chickens supplemented with Lactobacillus species probiotics during the first week of age have shown higher body weight than control (p < 0.05). The feed intake of week one of T₂ and T₃ were significantly higher (p< 0.05) than the T₁ (control). However, there was no significant difference (p> 0.05) in feed intake in the 2^nd, 3^rd, 4^th, and 5^{t h} weeks of all treatment groups. The present result showed that there was a significant body weight gain (p< 0.05) in all probiotic fed groups than the control group. The highest body weight gain was observed in chickens found in the T4 treatment group. Whereas the body weight gains significantly higher and improved the feed conversion (p<0.05) in the T₂ and T₄ than the T₁ (control). However, the feed conversion ratio was significantly influenced by probiotic inclusion in T₃ as compared to the control group.

Conclusion

Overall, the results suggest that Lactobacillus paracaseis sparacasei and Lactobacillus rhamnosus have a positive effect on the growth performance of broilers.

Effect of probiotics administration at different levels on the productive parameters of guinea pigs for fattening (Cavia porcellus)

Background

For more than 50 years, antibiotics have been used to maintain animal welfare and improve efficiency. Recently, antibiotics were found in the muscle, liver, and kidney of guinea pig carcasses put up for sale and human consumption, which is a public health issue. Probiotics are supplements of live microorganisms that, when administered in adequate doses, could replace growth-promoting antibiotics.

Aim

This study analyzed the effect of the administration of an oral probiotic mixture on the guinea pigs productive performance (Cavia porcellus).

Methods

Fifty male guinea pigs, weaned at 14 days of age, were distributed in a completely randomized design of five treatments with ten repetitions for each group. The treatments were CONTROL group without probiotic; PROB 1 given 1 ml of probiotic; PROB 2 with 2 ml of probiotic; PROB 3 with 3 ml of probiotic; and antibiotic growth promoter (AGP) was given 300 ppm zinc bacitracin. The microorganisms used in the probiotic were Enterococcus hirae, Lactobacillus reuteri, Lactobacillus frumenti, Lactobacillus johnsoni, Streptococcus thoraltensis, and Bacillus pumilus. Productive parameters were evaluated from weaning to 70 days of age.

Results

No statistically significant difference was found between the treatments on forage dry matter intake (DMI), concentrateconcentrate DMI, or total concentrate DMI (p > 0.05). Similarly, no statistical difference was found between the treatments in terms of final weight or weight gain (p > 0.05). Regarding the feed conversion ratio (FCR), there was a significant difference between treatments (p = 0.045); the CONTROL group had the highest FCR, followed by the AGP group, with the best FCR observed in the PROB 3 group (p < 0.05). In addition, significant statistical differences were found between CONTROL and PROB 2 (p < 0.05). Likewise, a significant linear effect of increasing doses of the probiotic was found (p = 0.01), which indicated that the feed conversion was better with a higher dose.

Conclusion

The treatments evaluated in this study significantly impacted the FCR in guinea pigs for fattening. Increasing doses of probiotics had a linear effect on FCR.

Effects of Clostridium butyricum on growth performance, metabonomics and intestinal microbial differences of weaned piglets

Background

Weaning stress of piglets causes a huge economic loss to the pig industry. Balance and stability of the intestinal microenvironment is an effective way to reduce the occurance of stress during the weaning process. Clostridium butyricum, as a new microecological preparation, is resistant to high temperature, acid, bile salts and some antibiotics. The aim of present study is to investigate the effects of C. butyricum on the intestinal microbiota and their metabolites in weaned piglets.

Results

There was no statistical significance in the growth performance and the incidence of diarrhoea among the weaned piglets treated with C. butyricum during 0–21 days experimental period. Analysis of 16S rRNA gene sequencing results showed that the operational taxonomic units (OTUs), abundance-based coverage estimator (ACE) and Chao index of the CB group were found to be significantly increased compared with the NC group (P < 0.05). Bacteroidetes, Firmicutes and Tenericutes were the predominant bacterial phyla in the weaned piglets. A marked increase in the relative abundance of Megasphaera, Ruminococcaceae_NK4A214_group and Prevotellaceae_UCG-003, along with a decreased relative abundance of Ruminococcaceae_UCG-005 was observed in the CB group, when compared with the NC group (P < 0.05). With the addition of C. butyricum, a total of twenty-two significantly altered metabolites were obtained in the feces of piglets. The integrated pathway analysis by MetaboAnalyst indicated that arginine and proline metabolism; valine, leucine and isoleucine biosynthesis; and phenylalanine metabolism were the main three altered pathways, based on the topology. Furthermore, Spearman’s analysis revealed some altered gut microbiota genus such as Oscillospira, Ruminococcaceae_NK4A214_group, Megasphaera, Ruminococcaceae_UCG-005, Prevotella_2, Ruminococcaceae_UCG-002, Rikenellaceae_RC9_gut_group and Prevotellaceae_UCG-003 were associated with the alterations in the fecal metabolites (P < 0.05), indicating that C. butyricum presented a potential protective impact through gut microbiota. The intestinal metabolites changed by C. butyricum mainly involved the variation of citrulline, dicarboxylic acids, branched-chain amino acid and tryptophan metabolic pathways.

Conclusions

Overall, this study strengthens the idea that the dietary C. butyricum treatment can significantly alter the intestinal microbiota and metabolite profiles of the weaned piglets, and C. butyricum can offer potential benefits for the gut health.

The effects of lactic acid bacteria and yeasts as probiotics on the growth performance, relative organ weight, blood parameters, and immune responses of broiler: A meta-analysis

Introduction: The number of publications in Scopus on this topic increased from less than 50 in 1995 to more than 250 in 2015. In other hand, Inconsistency in results about the correlation between yeast and lactic acid bacteria as probiotics has been evident since the early publications on use in broilers. Methods: A meta-analysis was conducted to determine relationship between lactic acid bacteria and yeast as probiotics to broiler diets on the growth performance, relative organ weight, blood parameters, and immune response of the broiler.  A database was designed based on published data that reported the use of probiotics on the broiler. The method used for selecting articles was based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) method. Articles selected were taken from PubMed, Web of science, Scopus, Google Scholar, and Science direct databases as well as individual. Results: The final database consists of 49 in vivo articles, 93 studies, and 225 treatments. The analysis statement in the system was a PROC MIXED procedure of SAS software. The level of probiotic increased (p <0.001) body weight, body weight gain, and feed intake of broiler. There was a reduction (p <0.01) on feed conversion ratio and mortality on the level probiotic given to broiler. Supplementation of probiotics in broiler diet increased (p <0.001) the weight of liver, spleen, gizzard, bursa of fabricius and carcass yield, while reduced (p<0.001) abdominal fat weight. The probiotic given increased the total of red and white blood cells (both at p < 0.001) but did not affect lymphocyte.  Discussion: It can be concluded the yeast act as supporting agent that serves lactic acid bacteria as probiotic increases the growth performance, relative organ weight, blood parameters, and immune response of the broiler.

The effects of lactic acid bacteria and yeasts as probiotics on the growth performance, relative organ weight, blood parameters, and immune responses of broiler: A meta-analysis

Introduction: The number of publications in Scopus on this topic increased from less than 50 in 1995 to more than 250 in 2015. In other hand, inconsistency in results about the correlation between yeast and lactic acid bacteria as probiotics has been evident since the early publications on use in broilers. Methods: A meta-analysis was conducted to determine relationship between lactic acid bacteria and yeast as probiotics to broiler diets on the growth performance, relative organ weight, blood parameters, and immune response of the broiler.  A database was designed based on published data that reported the use of probiotics on the broiler. The method used for selecting articles was based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) method. Articles selected were taken from PubMed, Web of science, Scopus, Google Scholar, and Science direct databases as well as individual. Results: The final database consists of 49 in vivo articles, 93 studies, and 225 treatments. The analysis statement in the system was a PROC MIXED procedure of SAS software. The level of probiotic increased (p <0.001) body weight, body weight gain, and feed intake of broiler. There was a reduction (p <0.01) on feed conversion ratio and mortality on the level probiotic given to broiler. Supplementation of probiotics in broiler diet increased (p <0.001) the weight of liver, spleen, gizzard, bursa of fabricius and carcass yield, while reduced (p<0.001) abdominal fat weight. The probiotic given increased the total of red and white blood cells (both at p < 0.001) but did not affect lymphocyte.  Discussion: It can be concluded the yeast act as supporting agent that serves lactic acid bacteria as probiotic increases the growth performance, relative organ weight, blood parameters, and immune response of the broiler.

The effects of lactic acid bacteria and yeasts as probiotics on the growth performance, relative organ weight, blood parameters, and immune responses of broiler: A meta-analysis

Introduction: The number of publications in Scopus on this topic increased from less than 50 in 1995 to more than 250 in 2015. In other hand, inconsistency in results about the correlation between yeast and lactic acid bacteria as probiotics has been evident since the early publications on use in broilers. Methods: A meta-analysis was conducted to determine relationship between lactic acid bacteria and yeast as probiotics to broiler diets on the growth performance, relative organ weight, blood parameters, and immune response of the broiler.  A database was designed based on published data that reported the use of probiotics on the broiler. The method used for selecting articles was based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) method. Articles selected were taken from PubMed, Web of science, Scopus, Google Scholar, and Science direct databases as well as individual. Results: The final database consists of 49 in vivo articles, 93 studies, and 225 treatments. The analysis statement in the system was a PROC MIXED procedure of SAS software. The level of probiotic increased (p <0.001) body weight, body weight gain, and feed intake of broiler. There was a reduction (p <0.01) on feed conversion ratio and mortality on the level probiotic given to broiler. Supplementation of probiotics in broiler diet increased (p <0.001) the weight of liver, spleen, gizzard, bursa of fabricius and carcass yield, while reduced (p<0.001) abdominal fat weight. The probiotic given increased the total of red and white blood cells (both at p < 0.001) but did not affect lymphocyte.  Discussion: It can be concluded the yeast act as supporting agent that serves lactic acid bacteria as probiotic increases the growth performance, relative organ weight, blood parameters, and immune response of the broiler.

Effects of hulless barley and exogenous beta-glucanase levels on ileal digesta soluble beta-glucan molecular weight, digestive tract characteristics, and performance of broiler chickens

The reduced use of antibiotics in poultry feed has led to the investigation of alternatives to antibiotics, and one such substitution is fermentable carbohydrates. Exogenous β-glucanase (BGase) is commonly used in poultry fed barley-based diets to reduce digesta viscosity. The effects of hulless barley (HB) and BGase levels on ileal digesta soluble β-glucan molecular weight, digestive tract characteristics, and performance of broiler chickens were determined. A total of 360 day-old broilers were housed in battery cages (4 birds per cage) and fed graded levels of high β-glucan HB (CDC Fibar; 0, 30, and 60% replacing wheat) and BGase (Econase GT 200 P; 0, 0.01, and 0.1%) in a 3 × 3 factorial arrangement. Beta-glucan peak molecular weight in the ileal digesta was lower with 30 and 60 than 0% HB, whereas the peak decreased with increasing BGase. The weight average molecular weight was lower at 0.1 than 0% BGase in wheat diets, whereas in HB diets, it was lower at 0.01 and 0.1 than 0% BGase. The maximum molecular weight was lower with 0.01 and 0.1 than 0% BGase regardless of the HB level. The maximum molecular weight was lower with HB than wheat at 0 or 0.01% BGase. Overall, empty weights and lengths of digestive tract sections increased with increasing HB, but there was no BGase effect. Hulless barley decreased the duodenum and jejunum contents, whereas increasing the gizzard (diets with BGase), ileum, and colon contents. The jejunum and small intestine contents decreased with increasing BGase. Ileal and colon pH increased with increasing HB, but there was no BGase effect. Treatment effects were minor on short-chain fatty acids levels and performance. In conclusion, exogenous BGase depolymerized the ileal digesta soluble β-glucan in broiler chickens in a dose-dependent manner. Overall, feed efficiency was impaired by increasing HB levels. However, HB and BGase did not affect carbohydrate fermentation in the ileum and ceca, although BGase decreased ileal viscosity and improved feed efficiency at the 0.1% dietary level.

Ways to minimize bacterial infections, with special reference to Escherichia coli, to cope with the first-week mortality in chicks: an updated overview

On the commercial level, the poultry industry strives to find new techniques to combat bird's infection. During the first week, mortality rate increases in birds because of several bacterial infections of about ten bacterial species, especially colisepticemia. This affects the flock production, uniformity, and suitability for slaughter because of chronic infections. Escherichia coli (E. coli) causes various disease syndromes in poultry, including yolk sac infection (omphalitis), respiratory tract infection, and septicemia. The E. coli infections in the neonatal poultry are being characterized by septicemia. The acute septicemia may cause death, while the subacute form could be characterized through pericarditis, airsacculitis, and perihepatitis. Many E. coli isolates are commonly isolated from commercial broiler chickens as serogroups O₁, O₂, and O₇₈. Although prophylactic antibiotics were used to control mortality associated with bacterial infections of neonatal poultry in the past, the commercial poultry industry is searching for alternatives. This is because of the consumer's demand for reduced antibiotic-resistant bacteria. Despite the vast and rapid development in vaccine technologies against common chicken infectious diseases, no antibiotic alternatives are commercially available to prevent bacterial infections of neonatal chicks. Recent research confirmed the utility of probiotics to improve the health of neonatal poultry. However, probiotics were not efficacious to minimize death and clinical signs associated with neonatal chicks' bacterial infections. This review focuses on the causes of the increased mortality in broiler chicks during the first week of age and the methods used to minimize death.

The Effects of Continual Consumption of Origanum vulgare on Liver Transcriptomics

Simple Summary

The use of phytogenic products has entered mainstream use in the livestock industry as an antibiotic alternative. These products, often based on herbs and spices with established antimicrobial properties, are generally considered as safe and natural, however, they are often administered in high doses and frequency. The direct effects of these products on the livestock animals remains under-reported. Using a transcriptomics, we show that supplementing 2% oregano in feed has direct effects on gene expression in the livers of broilers with a potential range of beneficial and negative side effects.

Abstract

Pathogen control is re-emerging as a significant challenge to the health of both humans and animals. The livestock industry is in the process of massively replacing in-feed antibiotics with organic production friendly plant-based products. Nutrigenomics as a science of the effects of food constituents on gene expression is shedding more light on both benefits and detrimental side-effects of feed additive prolonged consumption on the host, indicating the need to understand the feed-host interactions and their influence on the host disease profile. In this study, we investigated the effects of 2% oregano powder supplementation on the liver gene expression in healthy male broilers from the hatch to 6 weeks of age. Deep RNAseq was performed on average 113.3 million paired and quality trimmed sequences per sample and four samples for the control and treatment each. The results demonstrate the severity of oregano effect on liver gene expression with substantial modifications in steroid hormone regulation, fat and carbohydrate metabolism alterations and strong influence on the host disease and function profile. Oregano supplementation was able to interfere with the transcriptional effects of a range of registered drugs and to significantly transcriptionally inhibit a range of cancer disease categories including liver cancer, and to modify fat and carbohydrate metabolism.

Prevalence and antimicrobial resistance profiles of Salmonella species and Escherichia coli isolates from poultry feeds in Ruiru Sub-County, Kenya

Objectives

Contaminated poultry feeds can be a major source of E. coli and Salmonella infections in poultry. This study aimed at determining microbial load, prevalence and antimicrobial resistance profiles of Salmonella sp. and E. coli and associated resistance genes among isolates from poultry feeds.

Results

A total of 150 samples of different poultry feed types were randomly collected from selected sites within Ruiru Sub-County. The microbial load was determined, Salmonella sp. and Escherichia coli were isolated and antimicrobial susceptibility test carried out. Antimicrobial resistance genes were also screened among the resistant isolates. Out of analyzed samples, 58% and 28% contained Escherichia coli and Salmonella sp. respectively. Bacterial load ranged between 3.1 × 10⁵ and 3.0 × 10⁶ cfu/g. Highest resistance was against ampicillin (41%) for Salmonella sp. and (62%) for E. coli isolates. Ampicillin resistant isolates carried TEM and SHV genes. In addition, strB and Dfr resistance genes associated with streptomycin and cotri-moxazole were detected. All the isolates were susceptible to chloramphenicol and ciprofloxacin. The study reveals high bacterial contamination, presence of beta-lactamase, aminoglycoside and sulphonamide resistance genes across isolates from poultry feeds. Therefore, contaminated poultry feeds with bacteria are likely to lead to increase in antimicrobial resistant strains across the community.

16S rRNA Sequencing Analysis of the Gut Microbiota in Broiler Chickens Prophylactically Administered with Antimicrobial Agents

In poultry production, gut microbiota (GM) plays a pivotal role and influences different host functions related to the efficiency of production performances. Antimicrobial (AM) use is one of the main factors affecting GM composition and functions. Although several studies have focused their attention on the role of AMs as growth promoters in the modulation of GM in broilers, the consequences of higher AM concentrations administered during prophylactic treatments need to be better elucidated. For this purpose, 16S rRNA gene sequencing was performed to evaluate the impact of different prophylactic AM protocols on the composition and diversity of the broiler GM. Diversity analysis has shown that AM treatment significantly affects alpha diversity in ileum and beta diversity in both ileum and caecum. In ileal samples, the Enterobacteriaceae family has been shown to be particularly affected by AM treatments. AMs have been demonstrated to affect GM composition in broiler. These findings indicate that withdrawal periods were not enough for the restoral of the original GM. Further studies are needed for a better elucidation of the negative effects caused by an altered GM in broilers.

Cinnamon bark oil and coconut oil emulsions modified small intestinal motility and barrier function in laying hens in an ex vivo experiment

1. Plant extracts and oils are supplemented in diets for chickens due to their antimicrobial capacities; however, little information exists whether they influence intestinal motility and barrier function.2. The present study aimed to determine the effect of increasing levels of cinnamon bark oil (CBO; 0%, 0.038%, 0.076% and 0.151%) and coconut oil emulsions prepared with soy and sunflower lecithin on the contractile function of enteric wall muscles in the jejunum and ileum and jejunal barrier function in laying hens.3. For testing muscle contraction, mid-jejunal and ileal segments (n = 4 each per hen) from four laying hens were placed in a longitudinal orientation into isolated organ baths filled with Krebs buffer and fastened to force transducers. Muscle segments were induced to contract with acetylcholine and the effects of the oil emulsions on contraction were measured.4. For barrier function, distal jejunal pieces were stripped of serosa before mounting into Ussing chambers and recording changes in short-circuit current (I_SC) and transepithelial tissue conductivity (G_T) before and after addition of the respective emulsion.5. The CBO decreased the muscle tone, representing a relaxation of on average 36.2% and 42.6% for the jejunum and ileum, respectively, compared to before the addition (P < 0.001). Moreover, CBO linearly decreased the I_SC and G_T of the jejunal mucosa, indicating a greater absorption of anions and increased barrier function (P < 0.001). Only the coconut oil-sunflower lecithin emulsion relaxed the muscles, whereas both coconut oil-lecithin emulsions increased the I_SC but reduced the G_T of the jejunal mucosa, which suggested an increased cation absorption and decreased paracellular permeability, respectively (P < 0.05).6. In conclusion, CBO and coconut oil-lecithin emulsions showed the potential to increase jejunal barrier function, whereas CBO may be more efficacious to slow down digesta passage in the small intestine.

Minimal inhibitory concentration of seven antimicrobials to Mycoplasma gallisepticum and Mycoplasma synoviae isolates from six European countries

Mycoplasma gallisepticum and Mycoplasma synoviae are bacterial pathogens that cause disease in poultry, adversely affecting their health and welfare, and are a financial burden on producers. This manuscript describes the results of the MycoPath project that is the first international antimicrobial susceptibility programme for mycoplasma pathogens isolated from poultry. Improved comparative analysis of minimal inhibitory concentration (MIC) results from participating countries was facilitated by using one laboratory determining all MICs. Chicken and turkey isolates were obtained from France, Germany, Great Britain, Hungary, Italy and Spain during 2014-2016. One isolate per farm was retained. The MIC of seven antimicrobial agents was determined using a broth microdilution method, with Friis Medium (M. gallisepticum) or Modified Chanock's Medium (M. synoviae). Of the 222 isolates recovered, 82 were M. gallisepticum and 130 were M. synoviae. M. gallisepticum MIC_50/90 values were 0.12/0.5, 2/8, 0.5/4, 0.12/>64, 0.008/0.062, 0.008/32, 0.062/4 mg/l for doxycycline, enrofloxacin, oxytetracycline, spiramycin, tiamulin, tilmicosin and tylosin, respectively. For M. synoviae, the values were 0.5/1, 8/16, 0.5/1, 0.5/8, 0.25/0.5, 0.062/2 and 0.062/16 mg/l respectively. A bimodal MIC distribution for the fluoroquinolone (enrofloxacin) and the macrolides (spiramycin, tilmicosin and tylosin) indicate that both species have sub-populations that are less susceptible in vitro to those antimicrobials. Some differences in susceptibilities were observed according to host species, Mycoplasma species, and country of origin. This study provides a baseline of novel data for future monitoring of antimicrobial resistance in poultry Mycoplasma species. Additionally, this information will facilitate the selection of the antimicrobial agents most likely to be effective, thus ensuring their minimal use with targeted and correct therapeutic treatments.Highlights First large-scale pan-European collection of representative Mg and Ms isolates.MIC values assessed in central laboratory for Mg and Ms from chickens and turkeys.Range of MIC values for 82 Mg and 130 Ms isolates to seven licenced antibiotics shown.Data can be used to help determine Mg and Ms veterinary-specific breakpoints.

Probiotics and Herbs Combination in Commercial Feed Additives as Growth Promoter in Broiler Chicken

The prohibition on the use of Antibiotic Growth Promoter (AGP) causes the use of probiotics, herbs, enzymes and organic acids as an alternatives to AGP. This study aimed to determine the role of combination of probiotic and herbs in commercial feed additives on broiler performance. Sixty day-old male broiler were divided into 3 groups where each group consisted of 20 chickens with 4 replication each group. Group I was given commercial feed, group II was given commercial feed + AGP and group III was given commercial feed + combination of probiotics, herbs, enzymes and organic acids. All chickens were kept for 5 weeks. Body weight gain (BWG), body weight (BW) and Feed Convertion Ratio (FCR) were calculated every week. Carcass percentage was calculated at week 5. The results obtained from BWG and BW on group III at weeks 4 and 5 weeks were higher and significant difference (P<0.05) compared to groups I and II. The percentage of carcasses between groups did not have a significant difference (P>0.05). FCR values in group III from week 1 to weeks 5 were lower than groups I and II. The use of combination of probiotics, herbs, enzymes and organic acids has proven to have a good role on broiler performance so that it can replace AGP as a feed additive on broiler.