جستجوی مقالات مرتبط با کلیدواژه « طیور » در نشریات گروه « دامپزشکی »

Since the discovery of antibiotics, they have been used widely for disease control. Antibiotics were also found to be useful in growth promotion in the poultry industry. However, their overuse and misuse have led to bacterial resistance against them. Antibiotic resistance is a global issue that results in considerable health and economic losses. Marked antibiotic resistance against various antibiotics has been observed in poultry infections. To counteract the burdens of antibiotic resistance, various alternatives for antibiotics are being studied. These alternative approaches have also been subjects of interest in the poultry industry, as poultry infections result in dramatic economic loss, and in cases of zoonotic infections, the transmission of infection from chicken leads to dramatic health burdens in humans. Phage therapy, probiotics, and anti-microbial peptides administration are some examples of these alternative approaches. Another antibiotic alternative approach is called "enzybiotics". In enzybiotics, peptidoglycan hydrolases (endolysins) are used to degrade bacterial cell walls. These enzymes are mostly found in bacteriophages’ genomes because bacteriophages have to degrade the peptidoglycan layers of bacteria both to enter and exit their bacterial host. Bacterial genomes also contain some regions with peptidoglycan hydrolase properties which help bacteria in growth and division. The properties of various peptidoglycan hydrolases have been studied to find the more potent and applicable ones for future uses. Due to their advantages, endolysins are promising antibiotic alternatives. In this review, we will discuss the role of enzybiotics in the poultry industry. Also, endolysin advantages and limitations of their administration are discussed here.

Bacterial infections are one of the important causes of casualties and financial losses in the poultry industry. Despite the key role of antibiotics in the treatment of these infectious diseases, a significant increase in antibiotic resistance is considered a threat to societies. Several studies have investigated the antibiotic resistance levels of the different pathogenic bacterial strains in poultry. This study aimed to investigate the bacterial causes of death in chicken farms in Kazeroun City and also to evaluate the drug sensitivity of these bacterial strains.

The samples were obtained from the clinically-affected broiler chickens from 118 industrial poultry farms around Kazeroun City during 2021-2022. The samples were cultured on MacConkey agar and eosin methylene blue (EMB) agar culture media. Then, the antibiotic sensitivity of the samples that were positive for Escherichia coli was evaluated by different antibiotics (enrofloxacin, erythromycin, oxytetracycline, tylosin, gentamicin, doxycycline, danofloxacin, difloxacin, sultrim, florfenicol, flumequine, fosbac, chlortetracycline, colistin, lincospectin, and neomycin).

Among the 118 samples, 106 samples were positive for gram-negative bacteria. 100 of the 106 gram-negative samples were positive for Escherichia coli. All the Escherichia coli-positive samples were resistant to neomycin, chlortetracycline, flumoquine, gentamicin, and tylosin. Also, 99% and 97% of the Escherichia coli-positive samples were resistant to lincospectin and difloxacin, respectively. The highest antibiotic sensitivity of the samples was found to fosbac (94%) and Colistin (90%).

Due to the increase in resistance against common antibiotics, alternative methods are needed to slower drug resistance development and also reduce their resulting mortality. Biosecurity and using acidifiers and probiotics are among the ways to reduce bacterial infections and their need for antibiotic consumption.

Salmonellosis is increasingly recognized as a worldwide public health concern. Salmonella Infantis can infect both humans and animals, including poultry. It has been one of the most reported isolated serovars from different parts of the world. Although some research has been carried out on the pathogenesis of S. Infantis, little scientific understanding of its pathogenesis is available.

This study aimed to analyze the virulence genes of S. Infantis recovered from different sources of poultry in Iran.

Six virulence genes of 54 S. Infantis strains originated from broiler feces, poultry processing, and broiler carcasses were examined. Gene-specific polymerase chain reactions were designed and employed to detect the presence or absence of 6 important virulence genes (sopB, sopE, sitC, pefA, sipA, and spvC) in 54 S. Infantis isolates.

In this study, sopE, sitC, pefA, sipA, and sopB virulence genes were detected in 51(94.4%), 49(90.7%), 26(48.1%), 15(27.7%), and 5(9.2%) isolates, respectively. The spvC gene was not detected in any of the isolates. 

In the present study, a remarkably identical profile was found on virulence genes’ presence in isolates recovered from broiler feces and poultry processing plant sources, that is a public health concern. However, more S. Infantis isolates from various poultry sources, and human origin should be examined and analyzed. The findings of this survey can help the health researchers better understand the pathogenesis and epidemiology of S. Infantis in Iran.

Despite advances in food management techniques, foodborne illness remains a major concern. Contamination of Salmonella and Escherichia coli pathogens, especially in the poultry sector, is responsible for salmonellosis and other gastrointestinal illness, leading to millions of deaths worldwide. Overuse of antibiotics and other chemical treatments have further increased the emergence of antibiotic resistant bacteria.

This study aimed to study the efficacy of phages cocktail to reduce the load of E. coli and Samlonella spiked on poultry meat.

In this study, a broad spectrum cocktail of phages was used to lyse E. coli and Salmonella spiked on chicken meat.

Based on the result of the CFU drop assay, phages like E. coli 153T 3ii and Salmonella 191(3) were selected. Phage concentration of 0.01 MOI showed a reduction in E. coli and Salmonella count to 6 h and 2 h, respectively. Further, phages were tested on the surface of chicken meat. E. coli showed a 90% reduction up to 4 h, whereas Salmonella showed a 90% reduction up to 6 h. When phages were treated in combination, a significant reduction of up to 12 h was found with Salmonella phage, showing better antimicrobial activity.

The suitable concentration of a specific phage or phage cocktail can significantly reduce the bacterial count on chicken meat. Phage mediated biocontrol can be used as an alternative approach to eliminate enteric pathogens in the poultry industry.

One hundred and fifty samples suspected of coli bacillosis were isolated from broilers; laying hens and mother hens were sampled from 21 farms. The test was positive in 98 cases. And their sensitivity to ten types of antibiotics was investigated using antibiogram method, the disc diffusion method and the growth inhibition halo diameter in (mm). Ninety positive cases (60%) were meat breeding chickens and 8 positive cases (5.33%) were mother and laying hens. The antibiotic discs were related to tetracycline, ampicillin, difloxacin, enrofloxacin, doxycycline, sulfamethoxazole + trimethoprim, ciprofloxacin, calcitin, florfenicol, Fozbak. The biggest halo was related to florfenicol and Fosbak (21-22 mm). Also, the smallest halo was related to tetracycline and ampicillin (8-9 mm). Average halo diameter among ten antibiotics was measured from less than 8 mm to more than 22 mm. . All isolated Escherichia coli were at least 26% resistant to 7 types of antibiotics. Old generation antibiotics such as tetracycline and ampicillin were less effective than new generation antibiotics. In conclusion, the frequency of antibacterial resistance was high due to their excessive consumption and it would be a serious risk for the country's poultry industry and public health.

Bedding material must absorb moisture, reduce impacts, and allow chicken to express their natural behavior reducing the occurrence of injuries in the footpad and joints, and improving carcass quality and performance.

This study evaluated different bedding materials with different levels of inclusion of dried grass (Zoysia japonica) on the development of lesions in the locomotor system of broiler chickens.

One thousand eight-day-old male chicks of the Cobb 500® were distributed in a completely randomized design with a 3 × 2 factorial scheme: three levels of grass inclusion and two bedding materials (100% wood shavings; 100% rice husks; 25% grass and 75% wood shavings; 25% grass and 75% rice husks; 50% grass and 50% wood shavings; 50% grass and 50% rice husks). The birds at 21, 28, 35, and 42 days of age were evaluated for pododermatitis. Ten birds from each repetition were identified and evaluated weekly from 21 to 42 days for Gait score, latency to lie and leg angle (valgus and varus). At 43 days of age, 60 birds of each treatment were slaughtered and evaluated for femoral degeneration and tibial dyschondroplasia.

Different litter compositions did not affect the incidence of lameness, tibial dyschondroplasia and spondylolisthesis. Pododermatitis scores increased after 28 days when including 50% of grass.

Age contributes more to the development of locomotion injuries than does bedding material. It is recommended to use inclusions of dried grass only as bedding for young broilers.

Avibacterium paragallinarum causes infectious coryza that is an important disease of chickens associated with an acute upper respiratory infection, growth retardation, marked drop in egg production, reduced hatchability, and increased number of culls. Infectious coryza has been reported from all around the world including Iran where chickens are raised.

This study was conducted to isolate Avibacterium paragallinarum from the suspected cases of infectious coryza in the backyard and commercial layer chickens in three provinces of Tehran, Alborz, and Qazvin in Iran, to characterize the isolates by molecular methods and to determine their antimicrobial susceptibility profile.

Swab samples from eye secretions and mouth cavity were provided from five commercial laying farms (25 samples) and backyard chickens (20 samples) suspected of infectious coryza in Tehran, Alborz, and Qazvin provinces of Iran. Standard bacteriological and biochemical procedures were performed for the isolation and identification of Av. paragallinarum. The antimicrobial susceptibility of the recovered isolates was determined by the agar disk diffusion method. HPG-2 PCR was used to confirm Av. paragallinarum using the specific primers of N1 and R1, resulting in a 500 bp amplicon. PCR-amplified hmtp210 gene with the amplicon size of 1.6 kb was subjected to sequencing with the standard Sanger sequencing method and phylogenetically analyzed.

Three Av. paragallinarum isolates were obtained from all the cultured samples. Antimicrobial sensi-tivity test revealed that all three isolates were resistant to amoxicillin, oxytetracycline, streptomycin, ampicillin, and colistin while they were susceptible to cephalexin, ceftriaxone, florfenicol, gentamicin, linco-spectin, neomycin, and doxycycline. In phylogenetic analysis, two different genotypes of Av. paragallinarum were found.

In this study, Av. paragallinarum isolates recovered from layer flocks were genotypically closely related to the strains from serovar C while the isolate recovered from backyard chickens was closely related to serovar B strains. Our results showed that the antimicrobial susceptibility is highly variable among the Av. para-gallinarum isolates compared to previous studies. Future studies are required to develop better immunogenic strategies and eventually novel vaccine candidates to control the disease and reduce the risk of infection with multi-drug resistant Av. paragallinarum isolates.

Mycotoxins are secondary metabolites produced by fungi, especially Aspergillus spp, on grains and animal feeds. The most important mycotoxins are aflatoxins, including aflatoxin B1, B2, G1, and G2.

The present study was conducted to determine the occurrence of aflatoxins (B1, B2, G1, and G2) in the feed ingredients of livestock and poultry and to evaluate the effect of the season and spatial variation on aflatoxin contamination.

Ninety-three feedstock samples were collected from three major factories in Kermanshah province, Iran, during four seasons. The samples were analyzed by HPLC, and values for aflatoxins were determined. The sum of the aflatoxins was determined as the total for each sample. Data were analyzed using the SPSS software version 23 using general linear model (GLM) based on complete block design (samples and seasons).

Six out of 93 samples were positive for aflatoxin B1. Positive samples were mainly related to cold seasons. Moreover, no significant difference was found between the positive samples in terms of aflatoxins (B1, B2, G1, G2, and total).

The aflatoxin B1 levels in animal feed were found higher during rainy seasons compared to the summer season. The aflatoxin B1, carried over from feed to livestock and poultry products in different seasons, may cause high contamination in livestock and poultry products at levels over the tolerance limit. Therefore, continuous surveillance of aflatoxins is required in animal feeds to reduce animal and consequently human exposure

Salmonella in chicken, specially, the motile salmonellae, causes the food chain unsafe from farm to table and is considered a significant global threat to public health.

The present study was carried out for molecular detection of Salmonellae in commercial poultry using PCR.

The study was conducted for eight months, from July 2019 to February 2020, and a total of 26 poultry farms, including 15 broiler and 11-layer farms, were visited individually. Pooled faecal samples were obtained from the sheds. A total of 189 necropsy cases were examined for gastrointestinal lesions. Isolation and identification of the organism were done using microbe culture method, and the molecular characterization was performed via PCR targeting invA and ent genes.

The prevalence of salmonellosis in the broiler and layer farms was recorded at 20.0% and 45.4%, respectively, through the traditional gold standard culture method. From 189 necropsy birds, salmonellosis was recorded at 1.58% dead cases. Molecular detection of Salmonella isolates by PCR targeting invA gene was confirmed in 13.33% of the broiler farms and 36.3% of the layer farms. Further detection of Salmonella enteritidis was performed by PCR targeting ent gene by which 11.11% positivity was determined.

This study, focused on the Salmonella prevalence, highlighted the zoonotic importance of the bacterium in the commercial poultry farms, which can subsequently be dispersed into the human food chain causing harmful health effects.

Many studies tested different feed additives, among these additives, humic substances (HS) have been used in livestock and poultry diets. Humic substances commonly present in nature as they are created from the organic matter decomposition, and are normally found in the soil and natural water. Active components of HS consist of humic acid (HA), humus, ulmic acid, fulvic acid, humin and certain microelements. Humic acid is widely used as an alternative growth promoter for antibiotics in improving poultry performance and health. Moreover, supplementation of a commercial substance as a source of HS through the drinking water or diet improved the feed consumption, feed efficiency and weight gain of broiler chickens, and also improved egg weight, egg mass, and egg production of laying hens. This review describes the useful applications and recent facets of HA including its modes of action and various valuable uses in improving the production and health safeguarding of livestock and poultry.