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PubMed1978

Sources of Salmonellae in broiler chickens in Ontario.

Sources of Salmonellae infecting broiler chicken flocks in Ontario were investigated from July, 1975 to April, 1976. Three broiler flocks were investigated on each of four farms which received chicks from a common hatchery. Samples of feed and new litter were preenriched in nonselective broth subcultured to Salmonella-selective enrichment broth and plated on Salmonella-selective differential agar. Samples of used litter, water, culled chicks, insects, mice, wild birds and environmental swabs were not cultured initially in the nonselective broth. Fecal samples from principal and occasional flock attendants were examined for Samonellae. Salmonella infection, as judged by contaminated flock litter was detected in six flocks on two of the farms while the flocks on the other farms remained negative. Salmonellae were isolated from 23 of 412 feed samples (nine serotypes), six of 35 new wood shaving samples (four serotypes), one of 29 pools of culled chick viscera (one serotype) and 44 of 267 used litter samples (14 serotypes). These results indicate that broiler chicken flocks were infected with diverse Salmonellae introduced in day old chicks, pelleted feeds, wood shavings and residual contamination from the preceding flock.

Animal Feed↗
PubMed1976

[Antibiotic residues in organs and muscle tissues of broilers. I. Bacitracin, flavomycin, spiramycin and viriniamycin residues following administration of diets containing low levels of these antibiotics (author's transl)].

Two groups of broilers were fed two different feed mixtures. A feed containing a mixture of bacitracin, flavomycin, spiramycin and virginiamycin (20 ppm each) was administered to sixity broilers. Sixty other broilers were given a similar feed not containing any antibiotics. After slaughter, samples of kidney, liver and breast were examined for the presence of antibiotic residues. All samples were found to be negative for antibiotic residues. Four micro-organisms were used in performing the tests: Bacillus cereus Kiel, Bacillus subtilis 165, Bacillus subtilis BGA and Micrococcus luteus ATCC 9341.

Aminoglycosides↗
PubMed2026

Genomic characterisation of Enterococcus cecorum isolated from broiler chickens in the United Kingdom.

Enterococcus cecorum is an important poultry pathogen associated with lameness and increased mortality, leading to major welfare and economic impacts. Treatment is often challenging because disease is frequently detected late and the organism can localise in bone and joints, limiting antimicrobial efficacy. Presence of antimicrobial resistance (AMR) genes may further complicate treatment. Despite increasing global genomic research, only one recent study has investigated the phylogeny of E. cecorum from conventional UK broiler farms, using limited samples and a restricted time frame. In this study, 283 E. cecorum isolates were analysed, including 158 from the United Kingdom and 125 global non‑UK isolates. UK isolates comprised 123 archived by the Animal and Plant Health Agency (APHA) between 2003 and 2022, predominantly from clinical outbreaks with increased welfare culling and mortality, and 35 isolates from a UK study including clinical and environmental samples. Genome sequencing was used to assess phylogeny, AMR determinants and virulence factors (VFs). Single nucleotide polymorphism phylogenetic analysis identified eight major UK lineages with limited intra‑lineage diversity, indicating that UK isolates were genetically distinct from non‑UK populations. Using a 60‑SNP threshold, APHA isolates formed 18 subclusters, consistent with long‑term persistence and recurrent farm transmission, while multiple subclusters detected on some farms suggested repeated introductions. UK isolates carried fewer AMR genes than non‑UK isolates, with erm(B), lnu(C), tet(M) and tet(L) most prevalent. Screening of VF genes identified nine genes present in all isolates, with the remainder variably distributed. A subset of 60 UK isolates was examined for 13 previously described virulence‑associated genes, with phylogenetic clustering indicating associations between gene presence or absence and clinical status or mortality classification. The capsular polysaccharide gene cpsO was assessed in this subset and most non‑clinical or environmental isolates were cpsO‑negative, although several isolates from high‑mortality outbreaks also lacked this gene. Overall, this study provides insight into the phylogeny, AMR profiles and virulence gene diversity of E. cecorum within the UK broiler sector, supporting targeted surveillance and investigation of pathogenic mechanisms.

Antimicrobial resistance↗
PubMed2026

Prevalence, genomic characterization, and biofilm-forming capacity of extended-spectrum β-lactamase-producing Escherichia coli from faecal samples of broiler chickens in Jinan City, China.

The emergence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in food animals threatens both veterinary and human medicine by compromising critically important antimicrobials. This study characterized the prevalence, antimicrobial resistance profiles, molecular epidemiology, and virulence attributes of ESBL-producing E. coli isolated from broiler farms in Jinan City, China. From 600 faecal samples, 537 E. coli isolates were recovered (89.5 % isolation rate), with 71 (13.2 %) identified as ESBL producers. Antimicrobial susceptibility testing revealed markedly more severe resistance among ESBL-producing isolates, with complete ampicillin resistance (100 %) and high-level resistance to sulfamethoxazole/trimethoprim (94.37 %), streptomycin (87.32 %), chloramphenicol (78.87 %), and tetracycline (70.42 %). Resistance to extended-spectrum cephalosporins cefuroxime and ceftriaxone reached 43.66 % and 36.62 %, respectively, while amoxicillin/clavulanic acid susceptibility declined to 61.97 %. Whole-genome sequencing identified blaCTX-M-55 (29.58 %) as the predominant ESBL genotype, followed by blaCTX-M-64 (23.94 %), blaCTX-M-15 (19.71 %), blaCTX-M-14 (12.68 %), and blaCTX-M-65 (9.86 %). The plasmid-mediated colistin resistance gene mcr-1 was detected in 25.35 % of ESBL-producing isolates, indicating a substantial reservoir of last-resort antibiotic resistance determinants, though physical linkage between mcr-1 and ESBL-encoding genes remains undetermined due to short-read sequencing limitations. Multilocus sequence typing revealed ST117 (18.3 %) as the predominant sequence type, associated mainly with serogroup O78 (25.4 %). Virulence gene profiling demonstrated high prevalence of the serum survival gene iss (85.9 %), commonly associated with avian pathogenic E. coli, though avian pathogenicity was not experimentally confirmed. Notably, 90.14 % of ESBL-producing isolates demonstrated biofilm-forming capacity, with 16.90 % classified as strong biofilm producers forming mature, mushroom-shaped microcolonies. These findings demonstrate that broiler chickens in the sampled Jinan farms constitute a significant reservoir of multidrug-resistant, biofilm-forming ESBL-producing E. coli harboring clinically relevant genotypes, including mcr-1. The predominance of ST117, reported in both poultry and human clinical settings, along with extensive co-resistance profiles, underscores the value of integrated surveillance and antimicrobial stewardship in poultry production, though direct zoonotic transmission evidence requires further comparative genomic and epidemiological investigation.

Antimicrobial resistance↗
PubMed2026

Functional characterization of lncIMF_17214 in regulating intramuscular fat deposition of yellow-feathered broilers.

Intramuscular fat (IMF) content and lipid composition are key determinants of both the nutritional value and sensory attributes of poultry meat, yet the underlying regulatory mechanisms remain insufficiently elucidated. In this study, triglyceride (TG) content was employed as a quantitative phenotypic proxy to dissect the molecular basis of IMF deposition in yellow-feathered broilers. By integrating TG phenotypic data from 315 individuals with transcriptomic profiles and whole-genome resequencing datasets, a TG-associated long noncoding RNA (lncRNA), lncIMF_17214, was identified. Functional characterization revealed that lncIMF_17214 functions as a negative regulator of lipid deposition. Specifically, its knockdown led to significant increases in TG and total cholesterol concentrations, promoted lipid droplet accumulation, and decreased shear force in breast muscle, whereas its overexpression elicited the opposite effects. Mechanistically, lncIMF_17214 interacts with the RNA-binding protein CNBP, forming a regulatory complex that inhibits lipid accumulation. Furthermore, liver-directed overexpression increased the abundance of lncIMF_17214 in plasma exosomes, while liver-directed manipulation was associated with changes in hepatic and breast-muscle lipid deposition; direct exosome-mediated transfer to intramuscular adipocytes remains to be established. Transcriptomic profiling coupled with pathway enrichment analyses demonstrated that lncIMF_17214 predominantly influences steroid biosynthesis, unsaturated fatty acid metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. This suggests that it may be involved in the regulation of these pathways, although the underlying molecular mechanisms remain to be further elucidated. Collectively, these findings define a lncIMF_17214-centered regulatory axis linking intracellular and systemic lipid metabolism and provide a robust molecular framework for the targeted improvement of meat quality traits in yellow-feathered broilers.

Breast muscle↗
PubMed2026

Therapeutic potential of a novel virulent bacteriophage XQ-1 against avian pathogenic Escherichia coli infection in broiler chickens.

Avian Pathogenic Escherichia coli (APEC) represents a significant subgroup within extraintestinal pathogenic Escherichia coli strains and constitutes a substantial threat to the global poultry industry. Although the negative impacts of APEC have been mitigated considerably through antibiotic use, this practice has concurrently facilitated the widespread emergence and dissemination of antibiotic-resistant APEC strains worldwide. Consequently, bacteriophage has emerged as a promising alternative to antibiotics. In the current study, a novel virulent bacteriophage, designated XQ-1, was isolated from a sewage sample collected at a broiler chickens farm in Hubei Province, China. Notably, this bacteriophage exhibited the capability to lyse multiple APEC strains, including O1, O2, and O78 serotypes. The optimal multiplicity of infection (MOI) for bacteriophage XQ-1 was determined to be 0.001, yielding a maximum viral titer of 4.73 ± 0.31 × 1011 plaque-forming units (PFU) per milliliter. This bacteriophage displayed a latent period of 30 min, and a burst period of 80 minutes, corresponding to a burst size of 348 PFU per infected cell. Additionally, bacteriophage XQ-1 retained high lytic activity across a temperature range of 4-50 °C and maintained tolerance with a pH range of 3-11. Further in vitro studies demonstrated that bacteriophage XQ-1 holds potential as an effective disinfectant capable of directly lysing APEC strain JZ-1. In chick models subjected to intraperitoneal injection, exposure to APEC resulted in 100% mortality in chicks. However, treatment with bacteriophage XQ-1 significantly improved the survival rates of infected broiler chickens, reduced organ indexes, decreased bacterial loads in the liver and heart organs, and mitigated intestinal damage caused by APEC infection. Collectively, these findings suggest that bacteriophage XQ-1 represents a promising candidate for the prevention and treatment of APEC infections in poultry.

APEC↗
PubMed1977

Effect of transportation on blood metabolites in broilers.

1. Groups of 30 broilers from seven flocks were bled and weighed at the farm and a further sample of 10 broilers from each flock was transported from 8 to 16 km to the laboratory prior to bleeding and weighing. 2. One haematological and 11 biochemical analyses were made on each blood sample. 3. Although transportation did lead to significant differences in certain variables, the trends were consistent and sampling following transit is considered acceptable for clinical pathology studies.

Animals↗
PubMed1976

[Nitrogen metabolism of broilers fed N-15 labeled wheat. 3. Blood, liver, spleen, thymus, kidney, brain, pancreas, labile N reservoir].

Studies on the N metabolism of 4-week-old male broilers fed 15N Labelled wheat revealed a close correlation existing between the levels of 15N concentrations in the small intestine and in the plasma NPN fraction of the blood. The highest level of excess 15Natom0/0 in plasma proteins was noted as late as 20-30 hrs after administration of the last tracer dose. The mean life time of plasma proteins in broilers is less than 2.0 days. The rapid and statistically significant decrease of 15N frequency in the liver, spleen, thymus, and kidneys in the period from 12 hrs after withdrawal of the last 15N dose until the end of the trial reflects the intensity of N turnover in these organs. In the period from 6 hrs to 12 hrs after the last N intake the mean quantities of N in the liver, small intestine and kidneys decreased by 18%, 29%, 26% and 16%. The quantity of N accumulated in these organs after food intake is gradually released into the organism.

Animal Feed↗
PubMed1976

[Nitrogen metabolism in the broiler chicken determined by means of 15N labeled wheat].

Studies were made on the N and 15N excretion of 4-weeks-old male broilers fed 15N labelled wheat. The broilers excreted an average of 1143 mg N per bird per day. This would correspond to a level of N retention of 1105 mg N per day (49% of N intake) for birds consuming 2248 mg N daily. 53.9 mg of the 148 mg of 15N ingested on the first day of tracer administration (=36% of the amount administered) were excreted on the same day. Separation of the excreta by chemical means was not found to be a suitable method for the subsequent 15N isotope analysis of faecal and urinary N. Only colostomated birds can be used if the degree of labelling of faecal and urinary N has to be determined.

Animals↗
PubMed1978

[Effect of fasting on metabolism of free amino acids of various broiler tissues].

16 male broiler chicken fed with commercial-grade broiler fattening feed were killed in groups of four in intervals of 3, 6, 12 and 25 hours after the last food intake. The content of free amino acids was quantitatively determined in the small intestines, the liver and the complete muscular system. The highest concentration of free amino acids per gram of tissue could be detected in the small intestines between 3 and 6 hours and--phase shifted--in the liver between 6 and 12 hours after the last food intake. The changes of the concentration in the muscular system between the four measuring points were in most cases not statistically significant. The content of free amino acids in the three proofed tissues of fattening hybrids with a high demand of amino acids and a high protein synthesis performance was considerably above the values for rats as they are given in technical literature. The rhythmic changes of the concentration of free amino acids in the tissues in dependence on the interval between the last food intake and the killing require standardized conditions for metabolism-kinetic investigations of which the calculation of the content of free amino acids is part.

Amino Acids↗
PubMed2026

Genome-informed qPCR tracking revealed preferential persistence of Bacillus subtilis BS9 in the broiler chicken gastrointestinal tract.

This study aimed to develop a strain-specific quantitative PCR (qPCR) assay for Bacillus subtilis BS9 and characterize its persistence and spatial distribution in the broiler chicken gastrointestinal tract. Whole-genome sequencing and comparative genomic analysis identified a unique 110-bp sequence within a strain-specific genomic island, which was used to design a highly specific qPCR assay with excellent efficiency and sensitivity. In a 14-day in vivo trial, broiler chicks receiving daily oral doses of BS9 were analyzed using both culture-based methods and the newly developed qPCR. The assay was applied qualitatively, presence or absence, to detect BS9 in intestinal samples. BS9 was detected exclusively in the duodenum, jejunum, and cecum, with no presence in the gizzard or ileum. These findings demonstrate that BS9 exhibits region-specific persistence in the gut, likely reflecting adaptation to distinct physiological niches, which may contribute to its probiotic mechanisms.IMPORTANCEThis work provides the first detailed account of B. subtilis BS9's spatial persistence in poultry, revealing preferential adherence to specific intestinal regions. The strain-specific qPCR assay developed here offers a precise, culture-independent tool for tracking BS9 in complex gut environments. These insights into the genetic basis and tissue tropism of BS9 persistence advance our understanding of probiotic-host interactions and establish a framework for characterizing novel probiotic strains.

Bacillus subtilis↗
PubMedDate not supplied

Bacteria associated with beak necrosis in broiler breeder hens.

Beak necrosis occurred in 48 per cent of female broiler breeders used fro nutritional studies but none was found in male broiler breeders or in either sex of single comb white Leghorns. About 10 per cent mortality, probably largely due to beak necroses, occurred in the affected flock. Based on electron microscopic photographs of affected beak tissue, we suggest that in our study the breakdown of beaks was associated with the presence of a single morphological type of Gram-positive bacterium.

Animals↗
PubMed1976

A revised artificial insemination schedule for broiler breeder hens.

Broiler type hens maintained in individual cages were artificially inseminated with either 0.023, 0.035, or 0.047 ml. of pooled semen. Insemination intervals were nine, nine, and ten days on a repetitive basis. This schedule was adopted because it allowed an extension of the conventional insemination interval and yet remained compatible with a five-day industrial work-week. The results demonstrated that maintaining broiler breeder hens in cages and utilizing artificial insemination as a means of obtaining fertile eggs were feasible. The data also indicated that extending the insemination interval to 10 days is possible providing the number of spermatozoa inseminated is increased.

Animals↗
PubMed1976

A comparison of the daily energy needs of the normal and dwarf broiler breeder hen.

Feeding trials were conducted to determine optimum daily calorie intake needs for broiler breeder hens of normal and dwarf (dw) genetic lines. Pullets were grown to 24 weeks of age with limited feed intake and placed on one of five series of energy intakes. Series 3 represented a composite of energy intakes suggested by major broiler breeders with Series 1 and 2 representing a slower rate of energy increase and Series 4 and 5 representing more rapid rates. It was found that energy intakes suggested by a composite of the recommendations by the major breeders resulted in performance equal or superior to that of other groups tested. Using prediction equations the maximum daily needs for energy for normal sized hens was 422 M.E. kcal./day, with 418 mg./day of lysine and 380 mg./day of methionine.

Animal Feed↗
PubMed1976

Relation between methionine and inorganic sulphate in broiler rations.

In two experiments with 0-5 weeks old broiler chicks in battery-cages, it was examined whether the requirements for sulphur-containing amino acids in the ration could be reduced by addition of inorganic sulphate. The basal diet was a high energy practical-type broiler ration. The mineral mix included in this diet did not contain sulphates. The basal diet contained 0.73% methionine + cystine. By addition of synthetic methionine, experimental rations with 0.78, 0.82, 0.92 and 1.02% methionine + cystine, respectively, were obtained. The addition of methionine to the basal ration effected significant effects on weight gain (maximum 6-7% at 5 weeks of age) and on feed conversion (maximum 7-8% at 5 weeks of age). The addition of 0.1% Na2 SO4 (=0.068% inorganic sulphate) to the basal and the methionine supplemented diets resulted in an overall increase in weight gain at 5 weeks of age of 0.9% and a reduction in feed conversion of 1.2%; both effects were significant (P less than .05). However, the size of this effect proved to be independent on the contents of sulphur-containing amino acids in the ration. This indicates a small deficiency of the basal ration for inorganic sulphate.

Animal Feed↗
PubMed1976

Growth of broilers and quail fed Fusarium (Gibberella zeae)-infected corn and zearalenone (F-2).

There were no effects in commercial broilers after the long term ingesting of Fusarium-infected corn supplying 1, 10, and 30 p.p.m. zearalenone (F-2) in diets. Average gain and feed conversion were similar in all treatment groups. In the first feeding trial the average body weights were higher for males than for females, but the differences were not significant. Purified F-2, 30 P.P.M., was fed to broilers and no chronic effects were observed. Differences in mean body weights, between dietary treatments in the two Japanese quail lines were small and not significant after 4 weeks on diets containing 0, 10, and 25 p.p.m. F-2 from Fusarium infected corn.

Animal Feed↗
PubMed1976

Studies on the daily protein and amino acid needs of broiler breeder hens.

Feeding trials were conducted with broiler breeder hens to determine optimum daily intake of protein for maximum performance. Pullets were grown to 24 weeks of age on limited feed intake to maintain the body weight within the limits suggested by the breeder. A controlled-feeding system was used during the laying period with step-wise increase in calorie intakes. In the first study corn-soybean type diets were used to supply 14 to 22 grams of protein/day in 2 gram increments. In the second study daily protein intakes of 14.5 to 24 grams were compared. In addition, diets supplying 14.5 and 16 grams of protein daily were also fed with an additional 200 mg/day of lysine and methionine. The results of these studies suggest that the protein requirement of broiler breeder hens fed corn-soybean meal diets without supplemental amino acids is 20-22 grams per day.

Amino Acids↗
PubMed1977

The available lysine requirements of 7-9 week old sexed broiler chicks.

The experiments were conducted to determine the available lysine requirement of broiler chicks during the 7-9 week growing period. The chicks were sexed at day old, and the sexes were reared in separate pens in the same facility. Commercial-type broiler rations were fed from day old to 7 weeks of age. At 7 weeks the sexing errors were removed and the pens equalized to 50 birds per pen. The eight dietary treatments were replicated three times per sex. Graded levels of L-lysine-HCL were added to the basal ration to give a stepwise increase of 0.07% lysine per level. The available lysine requirement for female during the 7-9 week period was 0.64% for both growth and feed conversion. When this was expressed as a function of energy, 0.187% available lysine per megacalorie of metabolizable energy (M.E) per kg. of diet was required. The available lysine requirement for males during this period was 0.69 and 0.66% for gain and feed conversion, respectively. Expressed as available lysine per megacalorie of M.E. per kg. of diet, the values would be 0.202 and 0.193%, respectively.

Age Factors↗