Two broiler trials were designed to investigate the relationship between the concentration of non-starch polysaccharides (NSP) in wheat and 1) its nutritional value for broilers and 2) the efficacy of exogenous enzymes. In a balance trial, diets were formulated with 3 wheat cultivars (Rustic and Viscount-medium NSP, Centenaire-high NSP) and were tested with or without the addition of an exogenous enzyme mixture. The diets were fed to 144 male Ross 308 broiler chickens housed in digestibility cages. Total tract nutrient digestibilities and AMEn were measured from 18 to 22 d of age. In a performance trial, diets were formulated with wheat (medium NSP diet) or with wheat mixed with rye and barley (high NSP diet) and were tested with or without the addition of an exogenous enzyme mixture. The diets were fed to 960 male Ross 308 broilers housed in pens and broiler performance during starter, grower and finisher periods was measured.In the balance trial, wheat cultivar did not affect nutrient digestibility or AMEn. Enzyme addition caused a significant increase in nutrient digestibilities and AMEn for the diet formulated with the high NSP wheat Centenaire only. In the performance trial, feeding the high NSP diet resulted in a higher feed conversion ratio and lower final body weight compared to the medium NSP diet. The largest improvements by enzyme addition were observed in the high NSP diet.In conclusion, the study was not able to show a consistent relationship between the NSP concentration of wheat and its nutritional value, but did demonstrate that the effect of an enzyme mixture on nutrient digestibility or broiler performance depends upon the NSP concentration in the diet.
The present study was performed to explore the efficacy of the commercial anticoccidial vaccine (Coccivac B®) in broiler chickens using five field strains of Eimeria tenella that were isolated from five provinces in Egypt. This study also analyzed the ITS-1-rDNA sequence of these five strains and its corresponding sequence in the vaccine. In a floor pen experiment, 216 one-day-old commercial broiler chicks were classified into vaccinated and non-vaccinated groups. Each main group was classified into six subgroups. The chicks were challenged on the 28th day of age with 10(4) sporulated oocysts of one of the five field strains of E. tenella. Our results indicated that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella. Aligning the ITS-1 sequences from the five strains with the ITS-1 sequence of E. tenella from the vaccine revealed 96 % sequence similarity with the Kafer El-Sheikh strain, 94 % with the Gharbia strain, 90 % with the Alexandria strain, and 78 % with the Matrouh and Behera strains. While interesting, these similarity values were not useful for predicting the protection conferred by the vaccine against the five field isolates. However, based on the data reported here, we can conclude that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella.
The objective of this study was to determine standardized AA digestibility of corn, corn gluten meal, and 3 distillers dried grains with solubles (DDGS) using the precision-fed cecectomized rooster assay (PFR), the standardized ileal AA broiler chicken assay (SIAAD), and a newly developed precision-fed ileal broiler chicken assay (PFC). For the PFR, cecectomized roosters were precision-fed approximately 30 g of feed sample, and excreta were collected 48 h postfeeding. For the SIAAD, 16-d-old broilers were ad libitum fed a semi-purified diet containing the feed samples as the sole source of protein from 17 to 21 d, with ileal digesta collected at 21 d. For the PFC, 22-d-old broiler chickens were precision-fed 10 g of feed and ileal digesta were collected at 4 h postfeeding. For corn, the PFC yielded significantly higher digestibilities than the SIAAD and PFR for several AA. For corn gluten meal, the PFR yielded significantly higher values than the PFC for the majority of the AA, with the SIAAD yielding intermediate values. When 3 DDGS samples were evaluated, the PFR produced higher digestibilities than the PFC for all 3 DDGS samples for most of the AA. When comparing the PFR and the SIAAD, the PFR yielded higher values than the SIAAD for one DDGS, whereas there was generally no significant difference between these 2 methods for the other 2 DDGS samples. The results of this study indicate there were differences among standardized AA digestibility values for the PFR, SIAAD, and PFC in some instances. The differences among methods were not consistent; however, the PFR yielded higher digestibility values than the PFC for 4 of the 5 ingredient samples.
Pleurotus eryngii stalk residue (PESR) is a byproduct of the edible portion of the fruiting body. The present study was conducted to evaluate the effects of PESR on the oxidative status and meat quality of broilers. Two hundred fifty 1-d-old male broilers (Arbor Acre) were evenly divided by gender and randomly allocated into control (corn-soybean meal diet) or 1.0, 5.0, 10.0, or 20.0 g/kg dried PESR groups. The results revealed that at 35 d, the dried PESR groups displayed a significantly increased water-holding capacity and decreased storage loss of breast and thigh fillets when compared to the control group. Regarding fillets color, the L* (lightness) values were lower and the a* (redness) and b* (yellowness) values were higher following dried PESR supplementation. In 5.0-20.0 g/kg PESR supplementation groups, the activities of antioxidative enzymes were significantly elevated in serum, liver, spleen, and fillet tissues when compared to control group. Additionally, malondialdehyde production was slightly decreased in the PESR supplementation groups. Lower crude fat contents were observed in fillet tissues of 5.0-20.0 g/kg PESR groups when compared with the control group. In conclusion, PESR may potentially be used as an antioxidant to decrease lipid peroxidation and improve meat quality in broilers.
The effects of the in ovo injection of commercial diluent containing various levels of 25-hydroxycholecalciferol [25(OH)D3] on hatchability and hatching chick quality variables in Ross × Ross 708 broilers were examined in 2 trials. All treatment groups, each containing 21 and 40 eggs in trials 1 and 2, respectively, were randomly represented on each of 10 replicate tray levels of a single-stage incubator. On 18 d of incubation (doi), eggs were subjected to 1 of 6 treatments using a commercial multi-egg injector. Treatments included noninjected and diluent-injected controls, along with those that received diluent containing 0.15, 0.30, 0.60, or 1.20 µg of 25(OH)D3 in trial 1 and 0.20, 0.60, 1.80, or 5.4 µg of 25(OH)D3 in trial 2. Hatchability of injected eggs (HI) was recorded on 20.5, 21.0, and 21.5 doi, and embryonic mortalities through 21.5 doi were determined. On 21.0 doi in each trial, the BW, body length, and weights and moisture concentrations of the livers and yolk sacs of male and female chicks in each replicate group were determined. In a preliminary trial, the in ovo injection of 0.60 µg of 25(OH)D3 on 18 doi significantly elevated its serum level concentrations in embryos on 19.25 doi. In both trials, the HI of noninjected controls through 21.0 doi was higher than that of diluent-injected controls. In trial 1, the HI of eggs on 21.0 doi after being injected with 0.30, 0.60, or 1.20 µg of 25(OH)D3 was higher compared with that of diluent-injected controls, and in trial 2, the HI of eggs on 21.0 and 21.5 doi after being injected with 0.60 µg of 25(OH)D3 was higher compared with that of diluent-injected controls. In conclusion, the in ovo injection of 0.60 µg of 25(OH)D3 may be used to alleviate depressions in HI in Ross × Ross 708 broiler hatching eggs that can occur in response to the in ovo injection of commercial diluent.
Numerous cases of tenosynovitis appeared in France causing high morbidity in free-range and standard broilers. The main clinical findings were lameness, stunting and non-uniform bodyweights. Although the natural mortality was low, the economic losses due to birds that had to be removed from the flock prematurely, downgrading of carcases and lower average weights at slaughter were substantial. Postmortem examinations, bacteriological, virological and serological examination confirmed the aetiology of avian orthoreovirus (ARV)-induced tenosynovitis. The isolated ARVs were analysed serologically and genetically. Sequencing of σC RT-PCR products and phylogenetic analysis revealed a new type of ARV. The virus was not neutralised in serum neutralisation test using monovalent sera from vaccinated chickens. Together with the flock data, epidemiology of these recent reovirus outbreaks in France was reconstructed. It is concluded that these reovirus isolates differ serologically and genetically from the well described reovirus isolates used in commercial vaccines which were not capable of preventing the disease. The outbreaks resulted in substantial losses in broilers from vaccinated breeders.
The present study was conducted to investigate the effects of dietary synbiotic supplementation on growth performance, carcass composition, meat quality and muscular antioxidant capacity and mineral contents in broilers. 96 day-old male broiler chicks (Arbor Acres Plus) were randomly allocated to 2 groups, and each group consisted of 6 replicates with 8 chicks each. Birds were fed a corn-soybean meal basal diet supplemented with either 0 or 1.5 g · kg(-1) synbiotic consisted of probiotics (Bacillus subtilis, Bacillus licheniformis, and Clostridium butyricum) and prebiotics (yeast cell wall and xylooligosaccharide) from 1 to 42 days of age.
Genetic characterisation of antimicrobial resistance and virulence genes in Staphylococcus aureus isolated from commercial broiler chickens in the Durban metropolitan area, South Africa
- Journal of the South African Veterinary Association
- Published about 3 years ago
Antimicrobial resistance of Staphylococcus aureus in human and veterinary medicine is a serious worldwide problem. The aim of this study was to investigate the prevalence of S. aureus in commercial broiler chickens as well as to establish antimicrobial susceptibility and the distribution of genetic determinants conferring resistance and virulence. One hundred and ninety-four samples were aseptically collected from broiler chicken slaughterhouses and retail outlets around the Durban metropolitan area in South Africa. Microbiological and molecular methods were used to detect the presence of S. aureus as well as its resistance- and virulence-associated genes. Polymerase chain reaction (PCR) was used to confirm the presence of S. aureus by amplifying the nuc gene. Approximately 54% of 194 samples were positive for S. aureus. The disc diffusion technique was used to investigate antimicrobial susceptibility profiles of the S. aureus isolates to a battery of 10 antimicrobial agents, namely ampicillin, chloramphenicol, gentamicin, erythromycin, cefoxitin, kanamycin, streptomycin, tetracycline, vancomycin and trimethoprim. The results demonstrated that S. aureus isolates of abattoir origin had a high level (79.4%) of resistance to tetracycline, followed by ampicillin, vancomycin, cefoxitin, trimethoprim, erythromycin and streptomycin with resistance rates of 65.1%, 61.9%, 60.3%, 58.7%, 57.1% and 46.0%, respectively. Staphylococcus aureus isolates of retail origin exhibited higher antimicrobial resistance prevalence rates than those of abattoir origin. Tetracycline had the highest resistance rate (100%), followed by cefoxitin (91.7%), erythromycin (83.3%), streptomycin (83.3%) and kanamycin (66.7%). All isolates were resistant to two or more antimicrobial agents. Out of the four virulence genes that were screened, only two were detected (coagulase and protein A); however, their prevalence rates were very low. All antimicrobial resistance genes screened were detected (mecA, BlaZ and tetK), although their prevalence did not correspond with antimicrobial susceptibility testing.
White striping is a condition in broiler chickens characterized grossly by the occurrence of white striations, seen parallel to the direction of muscle fibers, on broiler breast fillets and thighs. Based on visual evaluation of the intensity of white striping, breast fillets can be categorized into normal (NORM), moderate (MOD), and severe (SEV) categories. This study was undertaken to evaluate the details of changes in histology as well as proximate composition occurring in the fillets with respect to the 3 degrees of white striping. In experiment 1, representative breast fillets for each degree of white striping (n = 20) were collected from 45-d-old broilers, approximately 2 h postmortem. From each fillet, 2 skeletal muscle samples were obtained and fixed in 10% neutral buffered formalin. To identify and differentiate the histological changes, slides were prepared and stained using hematoxylin and eosin, Masson’s Trichrome, and Oil Red O stains. In experiment 2, samples with 3 degrees of white striping were collected from 57-d-old birds for conducting proximate analysis. Major histopathological changes observed in the MOD and SEV samples consisted of loss of cross striations, variability in fiber size, floccular/vacuolar degeneration and lysis of fibers, mild mineralization, occasional regeneration (nuclear rowing and multinucleated cells), mononuclear cell infiltration, lipidosis, and interstitial inflammation and fibrosis. Microscopic lesions were visually scored for degeneration and necrosis, fibrosis, and lipidosis. The scale used to score the samples ranged from 0 (normal) to 3 (severe). There was an increase (P < 0.05) in mean scores for degenerative or necrotic lesions, fibrosis, and lipidosis as the degree of white striping increased from NORM to SEV. The results from the histopathological study were supported by the findings from proximate analysis confirming that the fat and protein contents of muscle increased (P < 0.05) and decreased (P < 0.05), respectively, as the degree of white striping increased. In conclusion, the histopathological changes occurring in white striping indicate a degenerative myopathy that could be associated with increased growth rate in birds.
Broilers and broiler meat products are highly contaminated with extended spectrum beta-lactamase (ESBL) or plasmid-mediated AmpC beta-lactamase producing Escherichia coli and are considered to be a source for human infections. Both horizontal and vertical transmission might play a role in the presence of these strains in broilers. As not much is known about the presence of these strains in the whole production pyramid, the epidemiology of ESBL/AmpC-producing E. coli in the Dutch broiler production pyramid was examined. Cloacal swabs of Grandparent stock (GPS) birds (one-/two-days (breed A and B), 18 and 31 weeks old (breed A)), one-day old Parent stock birds (breed A and B) and broiler chickens of increasing age (breed A) were selectively cultured to detect ESBL/AmpC-producing isolates. ESBL/AmpC-producing isolates were found at all levels in the broiler production pyramid in both broiler breeds examined. Prevalence was already relatively high at the top of the broiler production pyramid. At broiler farms ESBL/AmpC producing E. coli were still present in the environment of the poultry house after cleaning and disinfection. Feed samples taken in the poultry house also became contaminated with ESBL/AmpC producing E. coli after one or more production weeks. The prevalence of ESBL/AmpC-positive birds at broiler farms increased within the first week from 0-24% to 96-100% independent of the use of antibiotics and stayed 100% until slaughter. In GPS breed A, prevalence at 2 days, 18 weeks and 31 weeks stayed below 50% except when beta-lactam antibiotics were administered. In that case prevalence increased to 100%. Interventions minimizing ESBL/AmpC contamination in broilers should focus on preventing horizontal and vertical spread, especially in relation to broiler production farms.