Antimicrobial drug residues in poultry products and implications on public health: A review

In-tube solid phase extraction with graphitic-based polyurethane sponge as a superhydrophobic sorbent and determination of drug residues in foodstuffs using high-performance liquid chromatography

Veterinary drugs used in animal husbandry raise public health concerns due to their residues in the bodies of animals. This study employs a simple and quick sample preparation technique, in-tube solid phase extraction, to extract drug residues from foodstuffs, including eggs, honey, and water. This technique utilizes the synergy of graphitic-based materials and polyurethane sponges (PU) combined through dip coating method to make reusable sorbents for extracting drugs, including amoxicillin, paracetamol, ciprofloxacin, and cefixime. These prepared sorbents were characterized using FTIR, SEM, and XRD. HPLC analysis assessed the extraction efficiency, considering various parameters such as analyte concentration, sample solution pH, extraction time, type of eluting solvent, and graphitic-based polyurethane sponge reusability and stability. The proposed method exhibited a linear response for all three sorbents in the range of 0.03-1000 µg mL-1, with LOD 0.03-1.60 µg mL-1 and LOQ 0.18-4.84 µg mL-1. The % RSD ranged from 1.3 to 9.3 %, with recoveries of up to 98.42 %.

Bioefficacy of dietary inclusion of Nannochloropsis oculata on Eimeria spp. challenged chicks: clinical approaches, meat quality, and molecular docking

Although anticoccidial drugs have been used to treat avian coccidiosis for nearly a century, resistance, bird harm, and food residues have caused health concerns. Thus, Nannochloropsis oculata was investigated as a possible coccidiosis treatment for broilers. A total of 150 1-day-old male Cobb broiler chicks were treated as follows: G1-Ng: fed a basal diet; G2-Ps: challenged with Eimeria spp. oocysts and fed basal diet; G3-Clo: challenged and fed basal diet with clopidol; G4-NOa: challenged and fed 0.1% N. oculata in diet, and G5-NOb: challenged and fed 0.2% N. oculata. Compared to G2-Ps, N. oculata in the diet significantly (P < 0.05) decreased dropping scores, lesion scores, and oocyst shedding. Without affecting breast meat colour metrics, N. oculata improved meat quality characters. At 28 days of age, birds received 0.2% N. oculata had significantly (P < 0.05) higher serum levels of MDA, T-SOD, HDL, and LDL cholesterol compared to G2-Ps. Serum AST, ALT, and urea levels were all decreased when N. oculata (0.2%) was used as opposed to G2-Ps. Histopathological alterations and the number of developmental and degenerative stages of Eimeria spp. in the intestinal epithelium were dramatically reduced by 0.2% N. oculata compared to G2-Ps. Molecular docking revealed a higher binding affinity of N. oculata for E. tenella aldolase, EtAMA1, and EtMIC3, which hindered glucose metabolism, host cell adhesion, and invasion of Eimeria. Finally, N. oculata (0.2%) can be used in broiler diets to mitigate the deleterious effects of coccidiosis.

Pathological and pharmacovigilance monitoring as toxicological imputations of azithromycin and its residues in broilers

Background and Aim

The importance of monitoring antimicrobial residues in food is underlined by increasing worries about food safety and public health. The potential toxicity of azithromycin (Az) on broilers and its impact on chicken meat residues require further investigation. This study assesses Az's toxicity effects and associated risks in broiler chickens through evaluation.

Materials and Methods

One hundred and twenty chicks were distributed into four equal groups randomly. Each group received different daily oral doses of Az: 200 mg/kg for Az1, 100 mg/kg for Az2, and 50 mg/kg for Az3. The FAz group was given plain water. High-performance liquid chromatography was used to measure Az residue levels in muscle and liver. Oxidative markers (malondialdehyde [MDA], superoxide dismutase [SOD], catalase [CAT]), liver and kidney function tests, and histopathological examination were conducted.

Results

The levels of alanine aminotransferase and aspartate aminotransferase increased in Az1 and Az2 groups from 8 h to 3 days and decreased slightly in Az2 by 7 days, while they remained normal in Az3. The levels of uric acid and creatine in the Az1 and Az2 groups increased from 8 h to 3 days and subsequently decreased in Az2 by the 7th day. Az1 group showed the highest increase in MDA levels within 7 days. With higher Az doses, SOD and CAT levels showed a more significant decrease post-treatment. 9.1 μg/kg Az1 liver had the highest residues, whereas none were detected in muscle.

Conclusion

At higher doses, Az caused significant liver and kidney damage, whereas lower doses had negligible effects. Muscle tissue contains fewer Az residues than liver. Assessing risks and ensuring compliance with regulations necessitate constant surveillance of Az residues in food. The health implications and risk management insights necessitate further investigation into the long-term effects of Az residues.

Simultaneous Screening of 172 Veterinary Drugs by Modified QuEChERS-LC-MS/MS in TCM Galli Gigerii Endothelium Corneum

An analytical method was developed for the screening of 172 veterinary drugs in traditional Chinese medicine Galli Gigerii Endothelium Corneum by high-performance liquid chromatography tandem mass spectrometry. The samples were pretreated by a modified QuEChERS method. A Zorbax Eclipse plus C18 column (1.8 μm, 3.0 × 150 mm2, Agilent) was used for the separation of analytes by gradient elution. All analytes were detected by electrospray ionization mass spectrometry with multiple reaction monitoring mode. Good linearity with R ≥ 0.99 was exhibited for all analytes within the respective range. The recoveries of all monitored analytes ranged from 55.4 to 127.6% at three spiked levels (limit of quantitation-LOQ, 2-fold LOQ, 10-fold LOQ), with relative standard deviations <17.8%. The estimated LOQ levels were 0.2-20 μg/kg. The application of this method provides a reference for the safety control of traditional Chinese medicines.

Comprehensive Screening of Salinomycin in Feed and Its Residues in Poultry Tissues Using Microbial Inhibition Tests Coupled to Enzyme-Linked Immunosorbent Assay (ELISA)

Salinomycin is a coccidiostat approved as a feed additive for the prevention of coccidiosis in poultry. Official control of its residues is set by the Commission Delegated Regulation (EU) 2022/1644. The aim of our study was to assess the suitability of three microbial inhibition tests (MITs), Premi®Test, Explorer 2.0, and the Screening Test for Antibiotic Residues (STAR) linked to the enzyme-linked immunosorbent assay (ELISA), for the screening of salinomycin residues in the tissues of broiler chickens (breast and thigh muscle, heart, liver, gizzard, kidneys, lungs, spleen, skin, and fat) fed commercially produced feed containing 70 mg.kg-1 of salinomycin in the complete feed. The first residue screening (Sampling A) was performed on the last day of administration of the salinomycin-medicated feed (day 30), and the second screening (Sampling B) was performed on the day of slaughter (day 37) after the expiry of the withdrawal period with the feeding of non-medicated feed. Based on the quantitative confirmation of salinomycin residues in the examined chicken tissues by the ELISA method (Sampling A from 0.025 to 0.241 mg.kg-1; Sampling B from 0.003 to 0.076 mg.kg-1), all the MITs with the preference of the bacterial strain Bacillus stearothermophilus var. calidolactis ATCC 10149 demonstrated the ability to detect the residues of salinomycin in the examined tissues of broiler chickens at the level of the maximum residue limits set from 0.015 to 0.150 mg.kg-1 by Commission Implementing Regulation (EU) 2017/1914 and confirmed the relevance of their sensitivity to the coccidiostat salinomycin.

Veterinary Drug Residues in the Food Chain as an Emerging Public Health Threat: Sources, Analytical Methods, Health Impacts, and Preventive Measures

Veterinary medications are necessary for both contemporary animal husbandry and food production, but their residues can linger in foods obtained from animals and pose a dangerous human risk. In this review, we aim to highlight the sources, occurrence, human exposure pathways, and human health effects of drug residues in food-animal products. Following the usage of veterinary medications, pharmacologically active compounds known as drug residues can be found in food, the environment, or animals. They can cause major health concerns to people, including antibiotic resistance development, the development of cancer, teratogenic effects, hypersensitivity, and disruption of normal intestinal flora. Drug residues in animal products can originate from variety of sources, including water or food contamination, extra-label drug use, and ignoring drug withdrawal periods. This review also examines how humans can be exposed to drug residues through drinking water, food, air, and dust, and discusses various analytical techniques for identifying these residues in food. Furthermore, we suggest some potential solutions to prevent or reduce drug residues in animal products and human exposure pathways, such as implementing withdrawal periods, monitoring programs, education campaigns, and new technologies that are crucial for safeguarding public health. This review underscores the urgency of addressing veterinary drug residues as a significant and emerging public health threat, calling for collaborative efforts from researchers, policymakers, and industry stakeholders to develop sustainable solutions that ensure the safety of the global food supply chain.

Assessing the efficacy of the ovicidal fungus Mucor circinelloides in reducing coccidia parasitism in peacocks

The biological control of gastrointestinal (GI) parasites using predatory fungi has been recently proposed as an accurate and sustainable approach in birds. The current study aimed to assess for the first time the efficacy of using the native ovicidal fungus Mucor circinelloides (FMV-FR1) in reducing coccidia parasitism in peacocks. For this purpose, an in vivo trial was designed in the resident peacock collection (n = 58 birds) of the São Jorge Castle, at Lisbon, Portugal. These animals presented an initial severe infection by coccidia of the genus Eimeria (20106 ± 8034 oocysts per gram of feces, OPG), and thus received commercial feed enriched with a M. circinelloides suspension (1.01 × 108 spores/kg feed), thrice-weekly. Fresh feces were collected every 15 days to calculate the coccidia shedding, using the Mini-FLOTAC technique. The same bird flock served simultaneously as control (t0 days) and test groups (t15-t90 days). The average Eimeria sp. shedding in peacocks decreased up to 92% following fungal administrations, with significant reduction efficacies of 78% (p = 0.004) and 92% (p = 0.012) after 45 and 60 days, respectively. Results from this study suggest that the administration of M. circinelloides spores to birds is an accurate solution to reduce their coccidia parasitism.

Isolation and molecular characterization of multidrug‑resistant Escherichia coli from chicken meat

Antibiotics in animal farms play a significant role in the proliferation and spread of antibiotic-resistant genes (ARGs) and antibiotic-resistant bacteria (ARB). The dissemination of antibiotic resistance from animal facilities to the nearby environment has become an emerging concern. The present study was focused on the isolation and molecular identification of Escherichia coli (E. coli) isolates from broiler chicken meat and further access their antibiotic-resistant profile against different antibiotics. Broiler chicken meat samples were collected from 44 retail poultry slaughter shops in Prayagraj district, Uttar Pradesh, India. Standard bacteriological protocols were followed to first isolate the E. coli, and molecular characterization was performed with genus-specific PCR. Phenotypic and genotypic antibiotic-resistant profiles of all confirmed 154 E. coli isolates were screened against 09 antibiotics using the disc diffusion and PCR-based method for selected resistance genes. In antibiotic sensitivity testing, the isolates have shown maximum resistance potential against tetracycline (78%), ciprofloxacin (57.8%), trimethoprim (54.00%) and erythromycin (49.35%). E. coli bacterial isolates have shown relative resistant to amoxicillin-clavulanic acid (43.00%) and against ampicillin (44.15%). Notably, 64.28% E. coli bacteria were found to be multidrug resistant. The results of PCR assays exposed that tetA and blaTEM genes were the most abundant genes harboured by 83 (84.0%) and 82 (82.0%) out of all 99 targeted E. coli isolates, followed by 48.0% for AmpC (CITM) gene and cmlA (23.00%) for chloramphenicol resistance. It is notable that most of the isolates collected from chicken meat samples were multidrug resistant (> 3 antibiotics), with more than 80% of them carrying tetracycline (tetA) and beta-lactam gene (blaTEM). This study highlights the high risk associated with poultry products due to MDR-E. coli and promote the limited use of antibiotics in poultry farms.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03950-7.

Prophylactic and Therapeutic Efficacy of Ultrasonicated Rosmarinus officinalis Ethanolic Extract and its Chitosan-Loaded Nanoparticles Against Eimeria tenella Infected Broiler Chickens

PURPOSE

The in vivo efficacy of ultrasonicated Rosmarinus officinalis ethanolic extract (UROEE) and its chitosan-loaded nanoparticles (UROEE-CsNPs) was investigated as a dietary prophylactic agent and as a therapeutic treatment against Eimeria tenella infected broiler chickens.

METHODS

Chickens were infected with 4 × 104 E. tenella oocysts at 21 days old for primary infection and with 8 × 104 oocysts at 35 days old for secondary infection. Eleven experimental groups were conducted. Dietary addition of 100 mg/kg UROEE and 20 mg/kg for CsNPs as well as UROEE-CsNPs were included for prophylactic groups from day 1 to 42. The same doses were used for therapeutic treatment groups for 5 constitutive days. Oocyst output in feces was counted. Histopathological and immunohistochemical studies were conducted. Gene expression of pro-inflammatory cytokines as IFN-γ, IL-1β and IL-6 as well as anti-inflammatory cytokines as IL-10 and TGF-β4 was analyzed using semi-quantitative reverse transcriptase-PCR.

RESULTS

The results showed an efficacy of UROEE, CsNPs and UROEE-CsNPs in reduction of oocyst excretion and improving the cecal tissue architecture. CD4+ and CD8+ T lymphocytes protein expression were reduced. E. tenella infection lead to upregulation of pro-inflammatory cytokines as IFN-γ, IL-1β, IL-6 and anti-inflammatory cytokines as TGF-β4 following primary infection, while their expression was downregulated following secondary infection.

CONCLUSION

The dietary prophylactic additives and therapeutic treatments with UROEE, CsNPs and UROEE-CsNPs could decrease the inflammatory response to E. tenella as indicated by oocyst output reduction, histopathological improvements, CD4+ and CD8+ T cells protein expression reduction as well as reducing mRNA expression levels of the tested cytokines following primary and secondary infections. Consequently, these results will help to develop better-combating strategies for the control and prevention of coccidiosis on poultry farms as a dietary prophylactic agent or as a therapeutic treatment.

First insights on the susceptibility of native coccidicidal fungi Mucor circinelloides and Mucor lusitanicus to different avian antiparasitic drugs

BACKGROUND

The combined application of predatory fungi and antiparasitic drugs is a sustainable approach for the integrated control of animal gastrointestinal (GI) parasites. However, literature addressing the possible interference of antiparasitic drugs on the performance of these fungi is still scarce. This research aimed to assess the in vitro susceptibility of six native coccidicidal fungi isolates of the species Mucor circinelloides and one Mucor lusitanicus isolate to several antiparasitic drugs commonly used to treat GI parasites' infections in birds, namely anthelminthics such as Albendazole, Fenbendazole, Levamisole and Ivermectin, and anticoccidials such as Lasalocid, Amprolium and Toltrazuril (drug concentrations of 0.0078-4 µg/mL), using 96-well microplates filled with RPMI 1640 medium, and also on Sabouraud Agar (SA).

RESULTS

This research revealed that the exposition of all Mucor isolates to the tested anthelminthic and anticoccidial drug concentrations did not inhibit their growth. Fungal growth was recorded in RPMI medium, after 48 h of drug exposure, as well as on SA medium after exposure to the maximum drug concentration.

CONCLUSIONS

Preliminary findings from this research suggest the potential compatibility of these Mucor isolates with antiparasitic drugs for the integrated control of avian intestinal parasites. However, further in vitro and in vivo studies are needed to confirm this hypothesis.

Effects of short-term florfenicol exposure on the gene expression pattern, midgut microbiota, and metabolome in the lepidopteran model silkworm (Bombyx mori)

Florfenicol (FF), an alternative veterinary antibiotic for chloramphenicol, has been widely utilized in livestock breeding to prevent and treat bacterial diseases. However, the toxicological effects of FF have yet to be fully disclosed. The domesticated silkworm (Bombyx mori), a lepidopteran model, was selected to assess the toxicological effects of FF dietary exposure with multi-omics. The findings showed that high-dose (250 μg/L) FF exposure increased the whole cocoon weight. High-dose FF exposure affected the species richness and community diversity of the microbiota in the silkworm midgut. Biochemical processes and innate immunity were impacted by FF exposure. The KEGG pathways impacted by the midgut microbiota and their metabolites were compared, and several pathways were found to be related to the two ecosystems. In addition, the innate immunity and lipid metabolism pathways were impacted, and some of the differentially expressed genes were enriched in these pathways. These related pathways may involve crosstalk between the midgut microbiota shift, midgut biological functions, and global gene expression. Therefore, our study also advances the application of the silkworm larval model in assessing antibiotic metabolic toxicity and provides novel insights into the potential risks of FF.

Bacillus amyloliquefaciens Probiotics Mix Supplementation in a Broiler Leaky Gut Model

The supplementation of antimicrobial growth promoters (AGPs) has been banned in many countries because of the emergence of antimicrobial-resistant pathogens in poultry products and the environment. Probiotics have been broadly studied and demonstrated as a promising AGP substitute. Our study is centred on the effects of a multi-strain Bacillus-based probiotic product on broiler production performance and gut microbial profile in a dexamethasone-induced leaky gut challenge. Two hundred and fifty-six broiler chicks were hatched and randomly assigned into four groups (wheat-soybean meal basal diet (BD) = non-supplemented control (C), BD supplemented with dexamethasone in week 4 (CD), BD containing a probiotic from day one (P), and BD containing a probiotic from day one and supplemented with dexamethasone during challenge week 4 (PD)). The production performance and caecal, gizzard, jejunal lumen and jejunal mucosa swab microbiota were studied by 16S rRNA gene sequencing. The Bacillus probiotic product significantly improved production performance and altered caecal gut microbiota (p ≤ 0.05), but no significant impact on microbiota was observed in other gut sections.

Prebiotic effects of Talinum triangulare and Mangifera indica on slow growing broiler chickens (SASSO)

1

The study aim was to evaluate the prebiotic effects of Talinum triangulare and Mangifera indica used on slow growing broiler chickens.

2

Three hundred and sixty (360) slow-growing chicks of four weeks of age and similar weight were selected and divided into four (04) treatments (Positive Control, Negative Control, 2 % T. triangulare and 2 % M. indica) of 6 replicates with, fifteen (15) chicks per replicate, which made ninety (90) chicks per treatment.

3

At 12 week age, blood sample and cecal content were taken from 6 chickens per treatment to determine heamatological profile and fermentation parameters (Short Chain Fatty Acid). The data obtained were submitted to one-way analysis of variance (ANOVA) using the software R version 3.6.2 (R Core Team, 2019).

4

Results showed that growth performance, haematological parameters, acetic, butyric, valeric and caproic acids were similar between broilers fed with the leave powders and the positive control treatment. However, broilers fed with Talinum triangulare and Mangifera indica powders showed a lower mortality rate, compared to the negative and positive control treatments. Moreover, broilers fed with the leave powders showed significantly higher (p < 0.05) formic acid concentration than the other treatments.

5

Talinum triangulare and Mangifera indica leaves could have prebiotic properties because they stimulated the production of short-chain fatty acids that keep animals healthy.

Modulation of Immune Response and Cecal Microbiota by Dietary Fenugreek Seeds in Broilers

Fenugreek seeds (FSs) are a natural source of bioactive compounds that may modulate the immune system and gut microbiota in broilers. This study examined the effects of dietary fenugreek seed powder on immune-related gene expression and cecal microbiota composition in broilers. A total of 144 broiler chickens were randomly allocated to three dietary groups, CON (0 g/kg FS, FS5 (5 g/kg FS) and FS10 (10 g/kg FS), each with 6 replicates of 8 birds. Ileum tissues and cecal contents were collected on day 42 for the mRNA expression of inflammation and antimicrobial defense-related genes and cecal microbiome diversity, respectively. The results indicated that fenugreek seeds downregulated mRNA-level inflammation and antimicrobial defense-related genes: IL6, IL8L2, CASP6, PTGS2, IRF7, AvBD9, AvBD10, and AvBD11. Moreover, fenugreek seeds altered the cecal microbial community by increasing the population of Firmicutes and decreasing the population of Actinobacteriota, Gemmatimonadota and Verrucomicrobiota at the phylum level and increasing Alistipes, Bacteriodes and Prevotellaceae at the genera level. These findings suggest that fenugreek seeds have a positive impact on the immunological profile and microbiome of broiler chickens, possibly through the interplay of the immune system and the gut microbiome.

Magnetic solid phase extraction of aminoglycosides residue in chicken egg samples using Fe3O4-GO-Agarose-Chitosan composite

Difficulties in identification of drug residues in food products arise due to their trace amounts in complex matrices. An eco-friendly and low-cost agarose-chitosan-magnetic graphene oxide based adsorbent was synthesized and employed for determination of aminoglycosides from chicken egg samples through HPLC. Synthesized adsorbent was characterized by SEM, FTIR, XRD, and VSM. Among two investigated aminoglycosides, streptomycin was derivatized with ninhydrin while gentamicin was detected without its derivatization. Impact of experimental variables such as adsorbent dose, extraction time, temperature, pH, and analyte concentration on extraction efficiency was investigated. Statistical analysis for determination of streptomycin and gentamicin demonstrated excellent linearity in the range of 0.2-1.6 µg kg-1, LOQ of 0.3 and 0.6 µg kg-1 for streptomycin and gentamicin, respectively and LOD of 0.1 and 0.19 µg kg-1 for streptomycin and gentamicin, respectively with RSD of 2.5% and recoveries up to 94%. Regeneration studies revealed that composite film can be used four times without considerable reduction in its extraction efficiency.

Green microwave-prepared N and S Co-doped carbon dots as a new fluorescent nano-probe for tilmicosin detection

A straightforward, rapid, and selective fluorescent probe for determination of tilmicosin has been developed based on novel nitrogen and sulfur co-doped CDs (NS-CD). The NS-CDs were synthesized, for the first time, through green, simple one step microwave pyrolysis in only 90 s using glucose as carbon source and l-cysteine as nitrogen and sulfur source. This proposed synthesis method was energy-efficient and resulted in NS-CDs with high production yield (54.27 wt%) and narrow particle size distribution. Greenness of NS-CDs synthesis method was assessed using EcoScale and was proven to be excellent green synthesis. The produced NS-CDs were applied as a nano-probe for determination of tilmicosin in its marketed formulation and milk based on dynamic quenching mechanism. The developed probe showed a good performance for tilmicosin detection in marketed oral solution and pasteurized milk and linearity range of 9-180 μM and 9-120 μM, respectively.

Surveillance of veterinary drug residues in food commonly consumed in Singapore and assessment of dietary exposure

Non-judicious and indiscriminate use of veterinary drugs in animal husbandry may result in accumulation of residues in animal tissues, and consequently in food for human consumption. The abuse of veterinary drugs presents a potential risk to consumer health, especially if the residue level is higher than the health-based guidance value (HBGV) such as the acceptable daily intake (ADI). Contamination of drug residues in food also promotes the emergence of antimicrobial resistance (AMR) which poses a serious threat to public health globally. There has been limited information on the occurrence and dietary exposure to veterinary drug residues in Singapore to date. In this study, the occurrence of four classes of veterinary drugs, namely beta-agonists, coccidiostats, fluoroquinolones and macrolides, were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in food widely consumed by Singapore residents. The magnitude of dietary exposure was assessed based on the consumption profile of Singapore population. Out of 216 food samples, 9.72 % were detected positive with veterinary drug residues, where majority of the positive samples were poultry and its derived products, followed by eggs and egg products. 7 veterinary drugs, specifically ciprofloxacin, enrofloxacin, clopidol, diclazuril, lasalocid, nicarbazin and tilmicosin, were detected in the samples, with clopidol and enrofloxacin being the most frequently detected drugs. Dietary exposure was evaluated using the estimated daily intake (EDI) of the detected drugs and benchmarked against the corresponding acceptable daily intake (ADI). All the %ADI values were far less than 100 in both the average and high consumer scenarios, indicating that the health risk associated with dietary exposure to these drugs in Singapore is low.

Recent Advances in the Determination of Veterinary Drug Residues in Food

The presence of drug residues in food products has become a growing concern because of the adverse health risks and regulatory implications. Drug residues in food refer to the presence of pharmaceutical compounds or their metabolites in products such as meat, fish, eggs, poultry and ready-to-eat foods, which are intended for human consumption. These residues can come from the use of drugs in the field of veterinary medicine, such as antibiotics, antiparasitic agents, growth promoters and other veterinary drugs given to livestock and aquaculture with the aim of providing them as prophylaxis, therapy and for promoting growth. Various analytical techniques are used for this purpose to control the maximum residue limit. Compliance with the maximum residue limit is very important for food manufacturers according to the Food and Drug Administration (FDA) or European Union (EU) regulations. Effective monitoring and control of drug residues in food requires continuous advances in analytical techniques. Few studies have been reviewed on sample extraction and preparation techniques as well as challenges and future directions for the determination of veterinary drug residues in food. This current review focuses on the overview of regulations, classifications and types of food, as well as the latest analytical methods that have been used in recent years (2020-2023) for the determination of drug residues in food so that appropriate methods and accurate results can be used. The results show that chromatography is still a widely used technique for the determination of drug residue in food. Other approaches have been developed including immunoassay, biosensors, electrophoresis and molecular-based methods. This review provides a new development method that has been used to control veterinary drug residue limit in food.

Drivers of antimicrobial resistance in layer poultry farming: Evidence from high prevalence of multidrug-resistant Escherichia coli and enterococci in Zambia

Background and Aim

Inappropriate use of antimicrobials exacerbates antimicrobial resistance (AMR) in the poultry sector. Information on factors driving AMR in the layer poultry sector is scarce in Zambia. This study examined the drivers of AMR in the layer poultry sector in the Lusaka and Copperbelt Provinces of Zambia.

Materials and Methods

This cross-sectional study employed a structured questionnaire in 77 layer poultry farms in the provinces of Lusaka and Copperbelt, Zambia, from September 2020 to April 2021. Data analysis was conducted using Stata version 16.1. Antimicrobial resistance was defined as the presence of multidrug resistance (MDR) isolates. Multivariable regression analysis was used to identify drivers of AMR.

Results

In total, 365 samples were collected, from which 339 (92.9%) Escherichia coli and 308 (84.4%) Enterococcus spp. were isolated. Multidrug resistance was identified in 39% of the E. coli and 86% of the Enterococcus spp. The overall prevalence of AMR in layer poultry farms was 51.7% (95% confidence interval [CI]: 40.3%-63.5%). Large-scale farmers (Adjusted odds ratio [AOR] = 0.20, 95% CI: 0.04%-0.99%) than small-scale and farmers who were aware of AMR than those who were unaware (AOR = 0.26, 95% CI: 0.08%-0.86%) were less likely to experience AMR problems.

Conclusion

This study found a high prevalence of AMR in layer poultry farming linked to the type of farm management practices and lack of AMR awareness. Evidence of high MDR in our study is of public health concern and requires urgent attention. Educational interventions must increase AMR awareness, especially among small- and medium-scale poultry farmers.

Screening and quantification of antibiotic residues in poultry products and feed in selected areas of Bangladesh

Background and Aim

Antibiotic residues in livestock farming have been identified as a potential cause of antimicrobial resistance in humans and animals. This study aimed to determine whether antibiotic residues were present in the chicken meat, eggs, feces, and feed collected from all four districts in the Mymensingh division of Bangladesh.

Materials and Methods

To detect antibiotic residues in the collected samples, qualitative thin-layer chromatography (TLC) and quantitative high-performance liquid chromatography (HPLC) were used. A total of 230 samples were analyzed for antibiotic residues of commonly used 11 antibiotics. Out of these, 40 meat and 40 feces samples were collected from broilers and layers, 30 egg samples from ducks and layers, and 120 feed samples from broilers and layers from the study area. Thin-layer chromatography was used to screen the presence of antibiotic residues; TLC-positive samples were then subjected to further HPLC analysis to determine the residue concentrations.

Results

Thin-layer chromatography analysis revealed that 23.5% of the tested samples contained residues from six different antibiotic classes (tetracyclines, quinolones, beta-lactams, sulfonamides, aminoglycosides, and macrolides). Thin-layer chromatography analysis showed that 35% and 25% of the meat samples were positive for residues from the broiler and layer, respectively. About 15% and 30% of layer and duck egg samples had positive residues, respectively. Out of 120 feed samples analyzed, about 15.8% had various antibiotic residues. In addition, feces samples from broilers and layers had 50% and 35% antibiotic residues, respectively. A total of 2.5% meat and 3.3% egg samples had antibiotic residues above the maximum residue limit (MRL). Based on the findings of this study, the highest percentage of oxytetracycline, followed by doxycycline and ciprofloxacin, were detected in feed samples, and oxytetracycline was detected in meat and egg samples.

Conclusion

This study clearly showed the misuse of antibiotics in the poultry sector in Bangladesh. Although antibiotic residues below the MRL level are suitable for human consumption, they may result in antimicrobial drug resistance to pathogens.

Sulfonamides and β-lactam antibiotic residues and human health risk assessment in commercial chicken meat sold in Nairobi City, Kenya

The use of antibiotic pharmaceuticals in chicken husbandry has risen steadily over time. Antibiotic residues in chicken meat poses risks to human health in addition to their contribution to the advancement of antibiotic resistance. Despite the increased use of antibiotics in chicken farming in Kenya, assessments of the residues and human exposure have not been conducted. In this study, the sulfonamides (SAs); sulfapyridine (SPD), sulfadiazine (SDZ) and sulfamethazine (SMZ) and the β-lactams (βLs); ampicillin (AMP), penicillin G (PEG) and amoxicillin (AMX) were determined in three chicken meat types; ex-layers, broilers, and indigenous meat marketed in Nairobi City, Kenya. Residual SAs ranged from 0.1 to 154.4 μg kg-1, with SPD recording the highest concentration in ex-layers' chicken meat samples. A range of 19.7 to 309.0 μg kg-1of BLs was found, where the highest amount represented AMX in ex-layers. Mean AMX contents in all chicken types, and AMP in broilers were above the Maximum Residue Limits (MRLs). For SAs, only SPD mean content was above MRL in ex-layers. Human health risks from exposure to antibiotic-contaminated chicken meat was evaluated using % ADI. All tested βLs were of no risk (<1% ADI) to human health. SPD and SDZ posed considerable risk (1-5% ADI) in some chicken meat, whereas SPD in ex-layers' chicken meat posed distinctive risk (>5% ADI) to children. Considering the co-occurrence of different types of antibiotics in same samples, obtained MRLs and % ADI (for some of the antibiotics) are indicative of potential human health risks. Information is valuable in provoking response from concerned agencies and fostering activities that advocate for judicious use of antibiotics.

Preventing bacterial disease in poultry in the post-antibiotic era: a case for innate immunity modulation as an alternative to antibiotic use

The widespread use of antibiotics in the poultry industry has led to the emergence of antibiotic-resistant bacteria, which pose a significant health risk to humans and animals. These public health concerns, which have led to legislation limiting antibiotic use in animals, drive the need to find alternative strategies for controlling and treating bacterial infections. Modulation of the avian innate immune system using immunostimulatory compounds provides a promising solution to enhance poultry immune responses to a broad range of bacterial infections without the risk of generating antibiotic resistance. An array of immunomodulatory compounds have been investigated for their impact on poultry performance and immune responses. However, further research is required to identify compounds capable of controlling bacterial infections without detrimentally affecting bird performance. It is also crucial to determine the safety and effectiveness of these compounds in conjunction with poultry vaccines. This review provides an overview of the various immune modulators known to enhance innate immunity against avian bacterial pathogens in chickens, and describes the mechanisms involved.

Unveiling the Antibiotic Susceptibility and Antimicrobial Potential of Bacteria from Human Breast Milk of Pakistani Women: An Exploratory Study

Background

Human life quality and expectancy have increased dramatically over the past 5 decades because of improvements in nutrition and antibiotic's usage fighting against infectious diseases. Yet, it was soon revealed that the microbes adapted to develop resistance to any of the drugs that were used. Recently, there is great concern that commensal bacteria from food and the gastrointestinal tract of humans and animals could act as a reservoir for antibiotic resistance genes. Methodology. This study was intended for evaluating the phenotypic antibiotic resistance/sensitivity profiles of probiotic bacteria from human breast milk and evaluating the inhibitory effect of the probiotic bacteria against both Gram-negative and Gram-positive bacteria.

Results

The results point out that some of the isolated bacteria were resistant to diverse antibiotics including gentamycin, imipenem, trimethoprim sulfamethoxazole, and nalidixic acid. Susceptibility profile to certain antibiotics like vancomycin, tetracycline, ofloxacin, chloramphenicol, streptomycin, rifampicin, and bacitracin was also observed. The antimicrobial qualities of cell-free supernatants of some probiotic bacteria inhibited the growth of indicator bacteria. Also, antimicrobial properties of the probiotic bacteria from the present study attributed to the production of organic acid, bacterial adhesion to hydrocarbons (BATH), salt aggregation, coaggregation with pathogens, and bacteriocin production. Some isolated bacteria from human milk displayed higher hydrophobicity in addition to intrinsic probiotic properties like Gram-positive classification, catalase-negative activity, resistance to gastric juice (pH 2), and bile salt (0.3%) concentration.

Conclusion

This study has added to the data of the antibiotic and antimicrobial activity of some probiotic bacteria from some samples of Pakistani women breast milk. Probiotic bacteria are usually considered to decrease gastrointestinal tract diseases by adhering to the gut epithelial and reducing population of pathogens and in the case of Streptococcus lactarius MB622 and Streptococcus salivarius MB620 in terms of hydrophobicity and exclusion of indicator pathogenic strains.

Biosynthesis and characterization of zinc oxide nanoparticles using Nigella sativa against coccidiosis in commercial poultry

Coccidiosis causes huge economic losses worldwide. Current study evaluated the effect of biosynthesized Zinc oxide nanoparticles (ZnONPs) using Nigella sativa, on Eimeria tenella infected broilers. Scanning electron microscopy showed spherical ZnONPs with 50-100 nm diameter, Fourier transforms infrared spectroscopy revealed the functional groups involved in the reduction of zinc acetate dihydrate to ZnONPs, UV-vis spectroscopy showed a peak at 354 nm, and Zeta potential exhibited stability at - 30 mV. A total of 150, a day-old broiler chicks were divided into 5 equal groups. Control negative: uninfected and untreated; Control positive: Infected and untreated; 3rd, 4th and 5th group were infected orally with 5 × 10⁴ sporulated oocysts of Eimeria tenella and treated with 60 mg/kg ZnONPs, 1% Nigella sativa seeds and amprolium 125 ppm, respectively. ZnONPs significantly (p < 0.05) improved the growth performance in the infected birds and decreased the oocyst shedding and anti-coccidial index. A significant (p < 0.05) decrease in the level of aspartate transferase and alanine transferase, whereas, a significantly higher amount of antioxidants like catalase and superoxide dismutase in ZnONPs treated group was observed. Pro-inflammatory cytokines like IL-2 and TNF-α were significantly decreased by ZnONPs (p < 0.05). In conclusion, biogenic ZnONPs with Nigella sativa might have enhanced anticoccidial, antioxidant, and anti-inflammatory effects with improved growth performance.

Study on the Metabolic Transformation Rule of Enrofloxacin Combined with Tilmicosin in Laying Hens

There is often abuse of drugs in livestock and poultry production, and the improper use of drugs leads to the existence of a low level of residues in eggs, which is a potential threat to human safety. Enrofloxacin (EF) and tilmicosin (TIM) are regularly combined for the prevention and treatment of poultry diseases. The current studies on EF or TIM mainly focus on a single drug, and the effects of the combined application of these two antibiotics on EF metabolism in laying hens are rarely reported. In this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine the residual EF and TIM in laying hens and to investigate the effect of TIM on the EF metabolism in laying hens. In this paper, we first establish a method that can detect EF and TIM simultaneously. Secondly, the results showed that the highest concentration of EF in the egg samples was 974.92 ± 441.71 μg/kg on the 5th day of treatment. The highest concentration of EF in the egg samples of the combined administration group was 1256.41 ± 226.10 μg/kg on the 5th day of administration. The results showed that when EF and TIM were used in combination, the residue of EF in the eggs was increased, the elimination rate of EF was decreased, and the half-life of EF was increased. Therefore, the use of EF and TIM in combination should be treated with greater care and supervision should be strengthened to avoid risks to human health.

The role of feeds in the transmission of chicken pathogens in Dodoma Urban District, Tanzania

Chicken production is an important economic activity in Tanzania. Indigenous chickens are kept in rural areas, while exotic breeds are kept in urban areas. Due to their high productivity, exotic breeds are becoming important sources of protein in fast-growing cities. Dodoma is one of the cities growing very fast in Tanzania. As a result, production of layers and broilers has increased dramatically. However, diseases remain the major challenge to chicken production despite the efforts of livestock officers to educate people on good management practices. This has made farmers think that feeds may be the source of pathogens. The study's objectives were thus to identify the major diseases affecting broiler and layer chickens in the Dodoma urban district, as well as the potential role of feeds in pathogen transmission to chickens. A household survey was conducted to identify common diseases affecting chickens in the study area. Thereafter, locally prepared feed samples were collected from twenty shops available in the district to determine the presence of Salmonella and Eimeria parasites. The presence of Eimeria parasites in the feeds was determined by raising day-old chicks in a sterile environment for 3 wk while feeding them the feed samples collected. Fecal samples from the chicks were analyzed for the presence of Eimeria parasites. Salmonella contamination of the feed samples was determined in the laboratory through the culture method. The study found that coccidiosis, Newcastle disease, fowl typhoid, infectious bursal disease, and colibacillosis are the main diseases affecting chickens in the district. After 3 wk of rearing, 3 out of 15 chicks developed coccidiosis. In addition, about 31.1% of the feed samples showed the presence of Salmonella spp. The prevalence of Salmonella was highest in limestone (53.3%), followed by fishmeal (26.7%), and maize bran (13.3%). It has been concluded that feeds are potential carriers of pathogens. To reduce economic losses and the continuous use of drugs in chicken production, health authorities should assess the microbial quality of poultry feeds.

Efficacy of quorum sensing and growth inhibitors alone and in combination against avian pathogenic Escherichia coli infection in chickens

Avian pathogenic E. coli (APEC), a causative agent of colibacillosis, is associated with high mortality and morbidity which results in severe economic losses to the poultry industry worldwide. APEC can be transmitted to humans through the consumption of contaminated poultry products. The limited effect of the current vaccines and the advent of drug-resistant strains have necessitated the development of alternative therapies. Previously, we identified 2 small molecules (SMs; [quorum sensing inhibitor; QSI-5] and [growth inhibitor; GI-7]) with high efficacy in vitro and in chickens subcutaneously challenged with APEC O78. Here, we optimized the oral challenge dose of APEC O78 in chickens to mimic the infection in the natural settings, evaluated the efficacy of the GI-7, QSI-5, and combination of GI-7 and QSI-5 (GI7+ QSI-5) in chickens orally infected with APEC, and compared their efficacy to sulfadimethoxine (SDM), an antibiotic currently used to treat APEC. Using the optimized dose of each SM in drinking water, GI-7, QSI-5, GI7+ QSI-5, and SDM were evaluated in chickens challenged with the optimized dose of APEC O78 (1 × 10⁹ CFU/chicken; orally; d 2 of age) and grown on built-up floor litter. Reduction in mortality was 90, 80, 80, and 70% in QSI-5, GI-7+QSI-5, GI-7, and SDM treated groups compared to the positive control (PC), respectively. GI-7, QSI-5, GI-7+QSI-5, and SDM reduced the APEC load in the cecum by 2.2, 2.3, 1.6, and 0.6 logs and in the internal organs by 1.3, 1.2, 1.4, and 0.4 logs compared to PC (P < 0.05), respectively. The cumulative pathological lesions scores were 0.51, 0.24, 0.0, 0.53, and 1.53 in GI-7, QSI-5, GI-7+QSI-5, SDM, and PC groups, respectively. Overall, GI-7 and QSI-5 individually have promising effects as a potential antibiotic-independent approach to control APEC infections in chickens.

β-sitosterol as an alternative to oxytetracycline: Effect on growth performance, feed intake and utilization efficiency and viscera macromorphometry of Cobb 500 broiler chickens

Antibiotics are used to fortify broiler chicken feeds as growth promoters. Chronic antibiotic use pollutes the environment and causes the development of antibiotic resistance. Natural alternatives that mimic the properties of antibiotics, without causing health and environmental challenges are required. β-sitosterol has antimicrobial, antioxidant, digestive and immune system modulating and growth stimulating activities. We evaluated its potential to replace oxytetracycline as a growth-promoter in broiler chicken feeds. Two hundred and forty, one-day-old Cobb 500 broiler chicks were randomly allocated to four diets where β-sitosterol replaced oxytetracycline at 0 mg/kg (control; fortified with 50 mg/kg oxytetracycline), 500 mg/kg, 1000 mg/kg and 1500 mg/kg (w/w) feed and fed for 6 weeks: 2 weeks for each growth phase. Each diet was replicated thrice with 20 chicks per replicate. Initial, weekly and terminal body mass (TBM) and daily feed intake (FI) were measured. Body mass gain (BMG), average daily gain (ADG) and feed conversion ratio were computed. Terminally, the chickens were fasted for 4 h then slaughtered and dressed. Gastrointestinal tract (GIT) and GIT accessory viscera masses and small and large intestine lengths were measured. Dietary fortification with β-sitosterol had similar effects (P > 0.05) to oxytetracycline on the chickens' TBM, BMG, ADG, FI and utilisation efficiency and GIT organ macromorphometry. In conclusion, β-sitosterol can replace oxytetracycline in Cobb 500 broiler chicken feeds without compromising growth performance, feed intake and utilisation efficiency and GIT organ growth and development.

Multidrug-Resistant Gram-Negative Bacteria Contaminating Raw Meat Sold in Accra, Ghana

BACKGROUND

Efforts to combat antimicrobial resistance (AMR) should be based on the One Health approach, involving human health, animal health, and the environment. In Ghana, previous studies on AMR have given little attention to animal source food, a major route of transmission of antibiotic-resistant zoonotic pathogens. The aim of this study was to investigate the occurrence of multidrug-resistant (MDR) bacteria in meat sold in Accra.

METHODS

This was a cross-sectional study in which 270 meat samples (90 each of beef, goat meat, and chicken) were collected, and investigated for contamination with multidrug-resistant bacteria. The bacteria were subjected to susceptibility testing against amikacin (30 µg), ampicillin (10 µg), amoxicillin-clavulanate (20/10 µg), cefuroxime (30 µg), ceftriaxone (30 µg), ceftazidime (30 µg), cefepime (30 µg), ciprofloxacin (5 µg), trimethoprim-sulfamethoxazole (1.25/23.75 µg), ertapenem (10 µg), meropenem (10 µg), imipenem (10 µg), tigecycline (15 µg), and gentamicin (10 µg).

RESULTS

Thirty-two different types of bacteria, totalling 558, were isolated, the predominant being Escherichia coli (44.6%), Aeromonas hydrophila (19.9%), Vibrio cholerae (3.4%), Aeromonas veronii (3.2%), and Klebsiella pneumoniae (3.1%). The prevalence of MDR among the contaminating bacteria was 14.9%. The MDR distribution among the predominant bacteria was Escherichia coli (18.7%), Aeromonas hydrophila (11.1%), Vibrio cholerae and Aeromonas veronii (0.0% each), and K. pneumoniae (5.6%). Moreover, 2.0% of the contaminating bacteria were extended-spectrum beta-lactamase (ESBL) producers, all of which occurred in the chicken samples, and their distribution was: Escherichia coli (1.3%), Klebsiella pneumoniae, Pantoea spp., Enterobacter cloacae, and Serratia plymuthica (0.2% each).

CONCLUSIONS

The meat samples were heavily contaminated with Escherichia coli and Aeromonas hydrophila, and less frequently, with Vibrio cholerae, Klebsiella pneumoniae, and other organisms. The prevalence of multidrug-resistant bacteria was moderate (14.9%), while that of ESBL producers was low (2%).

Investigating the Role of Antibiotics on Induction, Inhibition and Eradication of Biofilms of Poultry Associated Escherichia coli Isolated from Retail Chicken Meat

Background: Widespread use of antibiotics as growth promoters and prophylactic agents has dramatic consequences for the development of antibiotic resistance. In this study, we investigated effects of selected antibiotics on bacterial biofilms and performed extensive antibiotic and VF profiling of poultry-meat associated E. coli strains. Methods: Antibiotic susceptibility was performed by a disc diffusion method, followed by molecular screening of resistance and virulence determinants. Further biofilm formation assays, MIC-p, MIC-b, MBIC and MBEC, were performed using standard tissue culture plate method. Results: In total, 83 (75%) samples were confirmed as E. coli from poultry sources, 26 different antibiotics were tested, and maximum numbers of the isolates were resistant to lincomycin (100%), while the least resistance was seen against cefotaxime (1%) and polymyxin B (1%). Overall, 48% of the isolates were ESBL producers and 40% showed carbapenemase activity; important virulence genes were detected in following percentages: fimH32 (39%), papC21 (25%), iutA34 (41%), kpsMT-II23 (28%), papEF9 (11%), papGII22 (27%) and fyuA13 (16%). Colistin showed remarkable anti-biofilm activity, while at sub-MIC levels, gentamicin, ceftriaxone and enrofloxin significantly (p < 0.01) inhibited the biofilms. A strong induction of bacterial biofilm, after exposure to sub-minimal levels of colistin clearly indicates risk of bacterial overgrowth in a farm environment, while use of colistin aggravates the risk of emergence of colistin resistant Enterobacteriaceae, a highly undesirable public health scenario.

Efficacy of Artemisia annua against Coccidiosis in Broiler Chickens: A Field Trial

(1) Background: Various studies on artemisinin and its derivatives have shown that Artemisia annua may be of therapeutic interest for different diseases, including chicken coccidiosis. This study aimed to evaluate the effects of Artemisia annua on farm-reared broiler chickens by analyzing both the anticoccidial efficacy and its effect on the intestinal microbiota of poultry. (2) Methods: The experiment was performed within three houses on a broiler chicken farm located in Romania. House 1 was the experimental group and received a diet with an addition of A. annua. Houses 2 and 4 were the control groups and received anticoccidials. The prophylactic efficacy of A. annua against coccidiosis was evaluated by recording the weight gain, feed conversion rate, number of oocysts per gram of feces, lesion score, and mortality rate. (3) Results: The chickens fed with A. annua showed a decreasing trend in the number of oocysts per gram of faeces, and their lesion score was 80% lower than in the control group. The weight gains of the chickens treated with A. annua was lower, whilst the feed conversion rate was better than in controls. (4) Conclusions: Artemisia annua showed promising results in the prophylaxis of coccidiosis. Overall, the broiler chickens that received A. annua presented promising zootechnical performances and medical data related to coccidiosis and gut microbiota.

Effect of Cooking Methods on Amphenicols and Metabolites Residues in Livestock and Poultry Meat Spiked Tissues

Foods of animal origin, as nutritional supplements, are usually consumed after cooking, but residues of amphenicols in fresh raw meat threaten human health. Therefore, this study was designed to evaluate the effects of boiling, deep-frying and microwave processing under different time conditions on the residue levels of amphenicols and metabolites in livestock and poultry meat. Antibiotic-free pork, beef, lamb and chicken samples were spiked with chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF) and florfenicol amine (FFA) standard solutions and made into homogeneous meat blocks. These positive mock meat blocks were processed using three different cooking methods, and the analyses were performed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results showed that cooking methods, time and food matrices were the main factors influencing the changes in amphenicols and metabolites residues in livestock and poultry meat. With the increase in cooking time, boiling processing was the most effective in reducing the four drug residues in livestock and poultry meat matrices, followed by deep-frying, while microwaving caused an increase in drug residue concentrations. Although boiling and frying processes are effective strategies to reduce amphenicols and metabolites residues in meat, it cannot be assumed that these residues can always decrease to levels that are safe for consumer health, especially when the drug residue concentrations in raw meat are above the maximum residue limits (MRLs). Therefore, it is not reliable to remove residues of amphenicols and metabolites from food by cooking. The solution to the food safety problem of veterinary drug residues must start from the breeding source and accelerate the implementation of antibiotic reduction, antibiotic substitution and antibiotic-free farming.

Ultrasensitive immunosensing of Penicillin G in food samples using reduced graphene oxide (rGO) decorated electrode surface

The impact of uncontrolled antibiotic use in animals has subsequently led to emergence of antibiotic-resistant bacteria among humans due to consumption of animal by-products. Hence, to investigate antibiotic contamination in animal origin food products, we have developed a reduced graphene oxide (rGO) based immunosensor using fabricated electrode conjugated with anti-Penicillin antibody (rGO/Pen-Ab) for sensitive detection of Penicillin G. To execute this, Penicillin was first conjugated with Bovine Serum Albumin (BSA) which was confirmed via chromatographic, spectroscopic and electrophoretic-based techniques against both the in-house developed Penicillin conjugate (Pen-BSA) as well as the commercial Penicillin conjugate (Com-Pen-BSA). Further, we fabricated electrode based on one step synthesized rGO and immobilized with antibodies generated against Pen-BSA (Pen-Ab), and Com-Pen-BSA (Com-Pen-Ab), separately for detection of Penicillin. Each synthesis and conjugation step was confirmed by different spectroscopic methods. For efficient working of the electrode, various parameters were optimized using Voltammetry. The limit of detection for Penicillin G against Pen-Ab and Com-Pen-Ab was determined as 0.724 pM and 0.668 pM respectively and both displayed negligible cross reactivity against other β-lactam antibiotics (Cefalexin and Ampicillin). Furthermore, antibiotics were also detected in spiked milk, egg and meat samples and the electrode was evaluated for repeatability and storage stability. In conclusion, in-house developed Pen-Ab showed better sensitivity as compared to Com-Pen-Ab. The fabricated rGO/Pen-Ab biosensor shows future potential for rapid detection of penicillin and other β-lactam antibiotics for safe consumption of animal by-products in humans.

Ionophore coccidiostats - disposition kinetics in laying hens and residues transfer to eggs

Poultry production is linked with the use of veterinary medicinal products to manage diseases. Ionophore coccidiostats have been permitted for use as feed additives within the European Union (EU) for the prevention of coccidiosis in various species of poultry with except of laying hens. The presence of chemical residues in eggs is a matter of major concern for consumers' health. Despite such prohibition of use in laying hens, they were identified as the most common non-target poultry species being frequently exposed to these class of coccidiostats. Many factors can influence the presence of residues in eggs. Carryover of these class of coccidiostat feed additives in the feed of laying hens has been identified as the main reason of their occurrence in commercial poultry eggs. The physicochemical properties of individual compounds, the physiology of the laying hen, and the biology of egg formation are believed to govern the residue transfer rate and its distribution between the egg white and yolk compartments. This paper reviews the causes of occurrence of residues of ionophore coccidiostats in eggs within the EU with special emphasis on their disposition kinetics in laying hens, and residue transfer into eggs. Additional effort was made to highlight future modeling perspectives on the potential application of pharmacokinetic modeling in predicting drug residue transfer and its concentration in eggs.

Environmental surveillance of antimicrobial resistance in a rapidly developing catchment

Development and spread of AMR from various sources such as hospitals, pharmaceutical industries, animal farms and human habitations is not well understood. We conducted a pilot study to assess the prevalence of AMR by taking a case of rapidly developing catchment in Western India. For this, we selected four sub-catchments/regions with a dominant source of antibiotics, viz. areas with (a) dense poultry farms (4 farms/km²), (b) sparse number of poultry farms (2 farms/km²), (c) agricultural fields and (d) habitation (village). The environmental samples (soil, litter and water) were subjected to Kirby-Bauer/antibiotic disc susceptibility test to assess the resistance pattern in the bacterial species. Preliminary investigations showed the presence of seven multidrug-resistant bacterial species in the litter from poultry farms, with five species having a MAR index greater than 0.2. No evidence of AMR was observed in the vicinity (water and soil) of the poultry farms. This could be attributed to the rigorous disinfection protocols followed at the poultry farms to prevent infection in the fresh batch of chickens. However, in agricultural fields where the litter is used as manure, seven multiple drugs resistant with two species scoring a MAR index greater than 0.2 were observed. MAR index of less than 0.2 was observed for Escherichia coli and Enterobacter species isolated from village and control site (soil), respectively, indicating negligible contamination by antibiotics at sub-catchments. This study provides an approach to investigate the effects of multiple factors on the prevalence of AMR at the catchment scale.

Low-dose florfenicol and copper combined exposure during early life induced health risks by affecting gut microbiota and metabolome in SD rats

The potential health risks associated with simultaneous presence of residues of heavy metals and antibiotics in the environment and food have been of wide concern. However, the adverse health effects of combined heavy metal and antibiotic exposure at low doses remain unclear. In this study, the effects of combined exposure to florfenicol and copper at low doses during early life on toxicity, gut microbiota, drug resistance genes, and the fecal metabolome were investigated in Sprague-Dawley (SD) rats. The results showed that combined exposure induced inflammatory responses and visceral injury as well as faster weight gain compared with florfenicol or copper exposure alone. Alpha and beta diversity indices indicated that the composition of the gut microbiota and the abundance of bacteria related to energy intake and disease in the combined exposure group were significantly altered. The increase in resistance genes (floR, fexA) induced by florfenicol exposure was suppressed under combined exposure to florfenicol and copper. The fecal metabolome also demonstrated that metabolic pathways related to energy intake and liver injury were significantly affected in the combined exposure group. In conclusion, this study shows that combined exposure to florfenicol and copper during early life can pose a nonnegligible health risk even if the exposure concentration of florfenicol or copper is below the safe limit.

Evaluation of Non-Fermented and Fermented Chinese Chive Juice as an Alternative to Antibiotic Growth Promoters of Broilers

The present study explores the application of CC juice as a suitable feed additive and alternative to conventional antibiotics. We performed a comparative study to investigate the effects of non-fermented and fermented CC juice on broiler productivity, meat quality, blood characteristics, intestinal characteristics, and microbiota associated with intestinal characteristics. A total of 800 one-day-old Ross 308 broiler chickens were randomly assigned to one of the four dietary treatment groups: (1) basal diet (negative control; NC); (2) basal diet + 0.01% enramycin (positive control; PC); (3) basal diet + 3% non-fermented CC juice (NCC; CC juice 10%, water 90%); and (4) basal diet + 3% fermented CC juice (FCC; CC juice 10%, water 90%, Lactobacillus plantarum SK4719). Feed and water were provided ad libitum. Intriguingly, all treatments showed similar results in terms of broiler productivity and chicken meat quality. Considering organ characteristics, the FCC group showed a low spleen weight and lower (p < 0.05) blood levels of AST and total cholesterol (TCHO). Regarding intestinal characteristics, the CC feed additive (NCC and FCC) resulted in a heavier intestinal weight (p < 0.05) without affecting the length ratio of the villi or the crypt compared to the control (NC or PC). NCC and FCC lowered the growth of intestinal pathogens (p < 0.01). In summary, the addition of FCC can maintain poultry health by improving blood compositions and inhibiting the growth of intestinal pathogens, leading to a productivity comparable to that of poultry treated with growth-promoting antibiotics.

Knowledge, Attitudes, and Practices of Community Pharmacy Professionals on Poultry Antibiotic Dispensing, Use, and Bacterial Antimicrobial Resistance in Zambia: Implications on Antibiotic Stewardship and WHO AWaRe Classification of Antibiotics

Globally, the inappropriate dispensing and use of antibiotics in animals has contributed to the development of bacterial antimicrobial resistance (AMR). In Zambia, there is insufficient information among community pharmacy professionals on antibiotic use (ABU) and AMR in food-producing animals. This study assessed community pharmacy professionals' knowledge, attitudes, and practices regarding poultry antibiotic dispensing, use, and bacterial AMR in the Lusaka district of Zambia. A cross-sectional study was conducted among 178 community pharmacy professionals between February and April 2022 using a semi-structured questionnaire. Data were analyzed using Stata version 17. Of the total participants (n = 178), 51.1% (n = 91) were pharmacists. The most dispensed antibiotic was oxytetracycline, a Watch antibiotic, mainly without prescriptions. Good knowledge of ABU and AMR was associated with work experience for more than one year (p = 0.016), while good practices were associated with male gender (p = 0.039) and work experience of more than one year (p = 0.011). The study found moderate knowledge, positive attitudes, and moderate practices of pharmacy professionals on poultry ABU and AMR. There was high dispensing of poultry antibiotics without prescriptions, which calls for strict implementation of antimicrobial stewardship and surveillance programs in poultry production in Zambia to reduce AMR.

Coccidiostats and Poultry: A Comprehensive Review and Current Legislation

Coccidiosis remains one of the major problems of the poultry industry. Caused by Eimeria species, Coccidiosis is a contagious parasitic disease affecting poultry with great economic significance. Currently, in order to prevent health problems caused by this disease, broiler farmers make extensive use of coccidiostats in poultry feed, maintaining animal health and, in some cases, enhancing feed conversion. The presence of unauthorized substances, residues of veterinary products and chemical contaminants in the food industry is of concern, since they may pose a risk to public health. As the use of coccidiostats has been increasing without any requirements for veterinary prescription, research and surveillance of coccidiostat residues in poultry meat is becoming imperative. This review presents an up-to-date comprehensive discussion of the state of the art regarding coccidiosis, the most used anticoccidials in poultry production, their mode of action, their prophylactic use, occurrence and the European Union (EU) applicable legislation.

Qualitative immunoassay for the determination of tetracycline antibiotic residues in milk samples followed by a quantitative improved HPLC-DAD method

Environmental contaminant is one of several problems harming people and wildlife. An example of current emerging contaminants are antibiotics residues that can present in water and food. Although antibiotics are intended to treat or prevent human and animal infections, antibiotics have also been used as animal food supplements for their ability to promote growth and feed efficiency. This overuse of antibacterial has resulted in the accumulation of antibiotics residues in food products which are eventually consumed by human. The continuous unnecessary exposure of human to antibiotics through the direct animals meet or milk, or indirectly through plants or soil can increase the chance of the emergence of multi drug resistance bacteria and consequently adversely affecting human health. New regulations have been imposed regarding antibiotics utilization. Due to the scarce of data regarding antibiotics residue conditions in different types of food intended for human consumption in Saudi Arabia, this study proposed an optimized chromatographic method (HPLC-DAD) followed by an immunoassay approach for specifically detecting tetracyclines antibiotics in animal milk samples. The method was carried out using an RP-C18 column with a mobile phase consisting of 0.01 M KH₂PO₄: acetonitrile:methanol (70:20:10, v/v/v) adjusted to pH 4. Improvements were observed in the method in terms of resolution and sensitivity. The protein precipitation method used for extraction demonstrated high percent recoveries of 85-101%. The method was validated according to the guidelines of the International Conference for Harmonization (ICH). It is evidently clear from these findings that the presence of tetracycline and oxytetracycline antibiotics residues in milk products from the Saudi market are below the maximum residual limits (MRLs).

Effects of bacteriophage supplement on the growth performance, microbial population, and PGC-1α and TLR4 gene expressions of broiler chickens

Bacteriophages (BP) are viruses that invade bacteria and propagate inside them, leading to the lysis of the bacterial cells. The aim of this study was to investigate the effect of adding BP to the broiler's diet and its effect on the performance, morphology and bacterial population of the gut, some immune responses and expression of some intestinal genes. Accordingly, dietary treatments were as follows: basal diet (control), and control + 0.3 g/kg colistin or 0.5, 1 and 1.5 g BP/kg of diet. BP increased the body weight gain and reduced the feed conversion ratio (FCR), as compared to the colistin treatment, in the finisher and overall period (P < 0.05). European efficiency factor was significantly higher in 1.5 g BP-fed birds, as compared to the control and colistin treatments. meanwhile, bacteriophage and colistin-fed birds had higher Lactobacillus and lowered coliform bacteria counts, as compared to the control treatment (P < 0.05). Cecal concentrations of propionate in the 1.5 g BP-fed birds were higher than those in the control treatment (P < 0.05). BP-fed birds had a significantly increased villus height to crypt depth ratio, as compared to the control treatment. BP increased the serum concentrations of the total antibody, immunoglobulin (Ig) M, and IgG, as compared to the control treatment (P < 0.05). In the ileum, the expression of the Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) gene was decreased by dietary BP supplementation (P < 0.05). Furthermore, Toll-like receptor 4 (TLR4) gene expression was down-regulated in the BP-fed birds, whereas Interleukin 10 (IL-10) gene expression was up-regulated (P < 0.05). Overall, the use of BP may be a promising alternative to growth-promoting antibiotics in broilers by altering the gastrointestinal tract microbiota, enhancing immunological responses and improving the gut's morphology.

Assessment of safety and quality aspects of boiling treatment of quail eggs

A total of 300 quail eggs were collected randomly from different markets in Cairo and Giza Governorates. Five eggs were represented as one egg sample. Shell and content of each egg were examined for their microbiological contents, sensory evaluation and study of Escherichia coli O157 survival in artificially contaminated eggs. Moreover, qualitative detection of antimicrobial residues by seven plates microbiologically bioassay and confirmed by validated high-performance liquid chromatography (HPLC) methods for positively reacted antimicrobials in raw and boiled samples. There was a significant difference (P &lt; 0·05) between the grading score of eggs after the boiling at 2-, 4-, 5- and 7-min. Based on the survival results, the refrigeration storage and boiling for 5 min of quail eggs was confirmed that such eggs are without E. coli O157. After the boil, the concentrations of oxytetracycline (OTC) and 4-Epi-OTC residues were significantly reduced, and there was no effect on the concentration of sulphadimidine (SDD), amoxicillin (AMO) and Diketo residues. Samples that exceeded the maximum residual limits (MRLs) were 17·0%, 12·0%, 10·0%, 16·0% and 14·0% for SDD, OTC, 4-Epi-OTC, AMO and Diketo, respectively. After boiling, no significant change was noted for SDD, AMO and Diketo, but all OTC and 4-Epi-OTC were completely below MRLs. Therefore, SDD and AMO with their metabolite (Diketo) are heat-stable antimicrobial residues with multiple human health hazards.

Evaluation of Novel Quorum Sensing Inhibitors Targeting Auto-Inducer 2 (AI-2) for the Control of Avian Pathogenic Escherichia coli Infections in Chickens

Avian pathogenic Escherichia coli (APEC) associated with colibacillosis results in high morbidity and mortality, and severe economic losses to the poultry industry. APEC is a zoonotic pathogen and can infect humans through contaminated poultry products. Vaccination and antibiotic treatment are currently used to control APEC infections; however, the limited effect of vaccines and the emergence of antibiotic-resistant strains have necessitated the development of novel therapeutics. Here, we evaluated seven quorum sensing inhibitors (QSI) identified in our previous study, in APEC-infected chickens. QSIs were administered orally (~92 to 120 μg/bird) and chickens were challenged subcutaneously with APEC. Among them, QSI-5 conferred the best protection (100% reduction in mortality, 82% to 93% reduction in lesions [airsacculitis, perihepatitis, lung congestion, pericarditis] severity, and 5.2 to 6.1 logs reduction in APEC load). QSI-5 was further tested in chickens raised on built-up floor litter using an optimized dose (1 mg/L) in drinking water. QSI-5 reduced the mortality (88.4%), lesion severity (72.2%), and APEC load (2.8 logs) in chickens, which was better than the reduction observed with currently used antibiotic sulfadimethoxine (SDM; mortality 35.9%; lesion severity up to 36.9%; and APEC load up to 2.4 logs). QSI-5 was detected in chicken's blood after 0.5 h with no residues in muscle, liver, and kidney. QSI-5 increased the body weight gain with no effect on the feed conversion ratio and cecal microbiota of the chickens. Metabolomic studies revealed reduced levels of 5'-methylthioadenosine in QSI-5-treated chicken serum. In conclusion, QSI-5 displayed promising effects in chickens and thus, represents a novel anti-APEC therapeutic. IMPORTANCE Avian pathogenic Escherichia coli (APEC), a subgroup of ExPEC, is a zoonotic pathogen with public health importance. Quorum sensing is a mechanism that regulates virulence, biofilm formation, and pathogenesis in bacteria. Here, we identified a novel quorum sensing autoinducer-2 inhibitor, QSI-5, which showed higher anti-APEC efficacy in chickens compared to the currently used antibiotic, sulfadimethoxine at a much lower dose (up to 4,500 times). QSI-5 is readily absorbed with no residues in the tissues. QSI-5 also increased the chicken's body weight gain and did not impact the cecal microbiota composition. Overall, QSI-5 represents a promising lead compound for developing novel anti-virulence therapies with significant implications for treating APEC infections in chickens as well as other ExPEC associated infections in humans. Further identification of its target(s) and understanding the mechanism of action of QSI-5 in APEC will add to the future novel drug development efforts that can overcome the antimicrobial resistance problem.

Effect of Graded Levels of Fenugreek (Trigonella foenum-graecum L.) Seeds on the Growth Performance, Hematological Parameters, and Intestinal Histomorphology of Broiler Chickens

Two experiments were conducted to evaluate the effects of fenugreek seeds (FS) as a potential alternative to antibiotic growth promoters in broiler chickens. In the first experiment, one-day-old Ross (n = 160) straight-run broilers were fed FS at 0 g, 2.5 g, 5 g, and 10 g/kg of diet during the starter (from 1 to 21 days) and finisher phase (from 22 to 35 days) with four replicates of ten birds each. In the second experiment, one-day-old Ross (n = 144) male broilers were fed 0 g, 5 g, and 10 g FS per kilogram of diet during the starter (from 1 to 21 days) and finisher phase (from 22 to 42 days) with six replicates of eight birds each. In addition to growth performance, hematological parameters and intestinal histomorphology were measured in the second experiment. FS linearly reduced the body weight gain (BWG) (p < 0.001), feed intake (FI) (p < 0.05), and increased feed conversion ratio (FCR) (p < 0.05) during the starter phase in both experiments. However, no significant effects on BWG, FI, and FCR were observed during the finisher phase. Moreover, the overall BWG and FI were linearly reduced (p < 0.05) with the increasing levels of FS, but BWG and FI were similar in the 5 g/kg FS group and control group. The inclusion of FS had a linear increase in white blood cell (WBC), heterophil, and lymphocyte count (p < 0.005) and the decrease in hematocrit % (p = 0.004) and total bilirubin (p = 0.001). The villus height and villus height: crypt depth ratio of jejunum and ileum were significantly lower in 5 g FS and 10 g FS treatments (p < 0.001) compared to the control. The result indicates that the dietary inclusion of FS reduces the early growth performance, increases the WBC counts, and negatively affects the intestinal morphology of broiler chickens.

Estimates of Dietary Exposure to Antibiotics among a Community Population in East China

BACKGROUND

Antibiotics are widely used in clinics, livestock farms and the aquaculture industry. A variety of antibiotics in foods and drinking water may lead to important and inadvertent dietary exposure However, the profile of dietary exposure to antibiotics in humans is not well-explored. East China is an economically developed area with a high usage of antibiotics and a high rate of antibiotic resistance (ABR). This study aimed to evaluate the total intake level of antibiotics in humans via foods and drinking water based on a community population in East China.

METHODS

A total of 600 local residents from 194 households were recruited into this study in Deqing County of Zhejiang Province since June 2019. Each subject was asked to fill a food frequency questionnaire to report their daily consumption of foods and drinking water. Tap water samples were collected from ten households and twenty-one antibiotics of five categories were selected to detect in drinking water. Data of antibiotic residues in animal-derived foods were obtained from the notification of unqualified edible agricultural products after special supervision sampling inspection in Deqing County. The human dietary exposure to antibiotics was estimated by combining the data of antibiotic contamination in foods and drinking water, and the information of dietary consumption.

RESULTS

Of twenty-one antibiotics selected, subjects were exposed to a total of sixteen antibiotics, ranging from 15.12 to 1128 μg/day via two main dietary routes (animal-derived foods and drinking water). The overall dietary exposure level varied greatly in the antibiotics detected and their sources. Compared with other antibiotics, enrofloxacin made the most contributions in terms of dietary exposure, with a median exposure level of 120.19 μg/day (IQR: 8.39-698.78 μg/day), followed by sulfamethazine (median: 32.95 μg/day, IQR: 2.77-162.55 μg/day) and oxytetracycline (median: 28.50 μg/day, IQR: 2.22-146.58 μg/day). The estimated exposure level via drinking water (at the ng/day level, median: 26.74 ng/day, IQR: 16.05-37.44 ng/day) was significantly and substantially lower than those via animal-derived foods (at the μg/day level, median: 216.38 μg/day, IQR: 87.52-323.00 μg/day). The overall dietary exposure level also showed differences in sex and age. Males and youths were more likely to be exposed to antibiotics via dietary routes than others.

CONCLUSIONS

The community population investigated in East China was extensively exposed to multiple antibiotics via dietary routes. Long-term exposure to low-dose antibiotics in animal-derived foods was the primary dietary exposure route, compared with drinking water. Enrofloxacin contributed to the major body burden of dietary exposure, based on the combination of consumption of aquatic products and considerable enrofloxacin residues in them. Although the human dietary exposure level to antibiotics via drinking water and animal-derived foods ranged from ng/day to μg/L, their chronic toxicity and the accumulation and spread of ABR may be potential hazards to humans. Therefore, long-term monitoring of antibiotic contaminations in foods and drinking water, and human dietary antibiotic exposure is warranted.