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PubMed2002

Responses of broiler chickens to cottonseed- and soybean meal-based diets at several protein levels.

Three experiments were conducted to evaluate the performance of broiler chicks fed diets with cottonseed meal (CSM) as the major protein source. Experiment 1 was a 3 x 2 factorial with three crude protein levels (17, 20, and 23%) by two protein sources, CSM or soybean meal (SBM). Diets were fed to male broilers (n = 840) in floor pens from 21 to 49 d of age. L-Lysine-HCl was added to keep lysine at 5.22% of protein. Protein source and level had significant (P < 0.001) effects on BW gain (BWG) and feed conversion ratio (FCR), respectively (no source by level interactions). The average BWG were 1.80, 2.00, and 2.00 kg for birds fed CSM-based diets, compared with 1.93, 2.09, and 2.21 for SBM-based diets (17, 20, and 23% protein, respectively). The average FCR were 2.56, 2.31, and 2.25 for CSM-fed broilers and 2.39, 2.16, and 2.08 for SBM-fed broilers. Significant effects of protein source or level were found for percentage of chilled carcass, fillets, tenders, saddles, and fat pads. In Experiment 2, male broiler chicks (n = 336) were used to determine the lysine requirement of chicks fed a corn and CSM-based diet with 20% CSM and 6% SBM. The basal diet contained by calculation 3,200 kcal/kg of ME, 20% CP, and 0.81% lysine. Graded levels of lysine (0.81 to 1.30% in increments of 0.07%) were fed to chicks from 10 to 20 d, and BW and residual feed were measured at 20 d. The requirement, as determined by breakpoint analysis, was 1.023+/-0.01% lysine (R2 = 0.84) for BWG and 1.028+/-0.02% lysine (R2 = 0.56) for FCR. In Experiment 3, a 2 x 2 x 4 factorial arrangement of treatments involved feeding CSM or SBM to male and female broiler chicks (n = 768) from 21 to 42 d at four dietary protein levels (17, 20, 23, and 26% CP). Lysine was kept at 5.5% of the dietary protein and consisted of the calculated minimum level, established in Experiment 2, plus 7%. Protein level, but not source, had a significant effect on BWG and FCR (P < 0.01 and P < 0.001, respectively) for males. The average BWG were 1.53, 1.74, 1.78, and 1.81 kg for birds fed CSM compared to 1.46, 1.72, 1.84, and 1.82 kg for those fed SBM (17, 20, 23, and 26% CP, respectively); average FCR were 2.36, 2.14, 2.05, and 1.97 for CSM compared to 2.35,2.04, 1.87, and 1.80 for SBM. Protein source and level significantly (P < 0.05) affected feed intake. Significant effects of protein source or level were found for percentage carcass, fillet, tenders, leg quarters, and fat pads. Females had similar qualitative responses. This study showed that at slightly higher protein levels CSM could replace SBM in broiler grower diets to achieve similar performance.

Animal Nutritional Physiological Phenomena↗

PubMed2002

Antioxidant enzyme activities and mitochondrial fatty acids in pulmonary hypertension syndrome (PHS) in broilers.

Major objectives of this study were to assess antioxidant protection and fatty acid profile in lung mitochondria and whole liver in broilers with pulmonary hypertension syndrome [(PHS; with and without high dietary vitamin E (VE)] (Experiment 1) and in broilers that did not develop PHS but were genetically selected (S) or not selected (NS) for resistance to PHS (Experiment 2). In Experiment 1, lung mitochondrial glutathione peroxidase (GSH-Px) activity was elevated in broilers with PHS compared to controls, broilers fed high VE, and broilers fed high VE with PHS (VE-PHS), but there were no differences in GSH reductase (GSH-Rd) among groups. In liver tissue, GSH-Px was also elevated by PHS but was lower in VE and VE-PHS groups than in controls. There were no differences in liver GSH-Rd, superoxide dismutase (SOD), or gamma-glutamylcysteine synthetase (gamma-GCS) activities with the exception that gamma-GCS was higher in the VE-PHS group than in the other groups. In Experiment 2, S lung mitochondria exhibited lower GSH-Px and higher GSH-Rd compared to NS broilers. In the liver, there were no differences in GSH-Px, GSH-Rd, or gamma-GCS, but SOD was lower in S compared to the NS broilers. High VE increased the percentage of saturated fatty acids and decreased the percentage of unsaturated fatty acids in lung mitochondria in Experiment 1; there were no differences in fatty acid content between S and NS mitochondria in Experiment 2. Thus, it appears that GSH recycling enzyme activities are affected by PHS and high VE presumably in response to differences in oxidative stress and that genetic resistance to PHS is associated with an inherently better capability to metabolize oxidants in lung mitochondria. The increase in saturation of lung mitochondrial fatty acids with high dietary VE would presumably make them more resistant to oxidative stress and, thus, reduce the level of PHS-induced oxidative stress.

Animals↗

PubMed2003

Broiler survivors of intravenous micro-particle injections: evaluation of growth, livability, meat quality, and arterial blood gas values during a cyclic heat challenge.

When broilers are exposed to high ambient temperatures, their cardiac output can increase by 20 to 50%. Previously, we developed an intravenous micro-particle injection technique to select broilers having a cardiopulmonary capacity capable of accommodating increases in cardiac output associated with fast growth and cool temperatures. In the present study, male broilers were injected at 18 to 20 d of age with cellulose micro-particles sufficient to trigger >50% mortality by 35 d of age. The survivors of micro-particle injections (cellulose survivors) and saline-injected flock mates (control group) were exposed to a moderate cyclic heat challenge (peak temperature of 35 to 37 degrees C) beginning on d 36 and continuing through d 57. We tested the hypothesis that if the cellulose survivors represent the population cohort having the most robust cardiopulmonary capacity, then during a subsequent heat challenge these survivorspotentially may perform better than their unselected flock mates. Based on data combined from two independent experiments, the cellulose survivors exhibited improved livability and body weight gain when compared with their unselected flock mates during the cyclic heat challenge. Meat quality characteristics did not differ between the groups. In a third experiment, cellulose survivors and saline-injected male broilers were reared at thermoneutral temperatures or were exposed to a cyclic heat challenge beginning on d 36. Arterial blood samples were collected from unanesthetized birds at 47 to 49 d of age and were analyzed for pH, partial pressure of CO2, bicarbonate, partial pressure of O2, and saturation of hemoglobin with O2. The blood gas values for the cellulose survivors and saline-injected broilers did not differ within a temperature regimen, regardless of whether the broilers were chronically acclimated to heat or were exposed to an acute heat challenge at the end of the experiment. The cellulose survivors did not differ in susceptibility to panting-induced respiratory alkalosis or hypoxemia when compared with their saline-injected flock mates. Overall, these observations indicate that selection for a robust cardiopulmonary capacity can confer advantages in growth and livability without affecting meat quality when broilers are exposed to a moderate heat challenge.

Animals↗

PubMed2003

Effect of experimental chlorate product administration in the drinking water on Salmonella typhimurium contamination of broilers.

The crop is a known source of Salmonella and Campylobacter contamination. Previously, we evaluated lactic acid in the drinking water during a simulated pretransport feed withdrawal (FW) and reported 0.44% lactic acid significantly (P < 0.05) reduced the number of Salmonella recovered in market-age broiler crops. However, total consumption of the organic acid-treated drinking water was reduced. Presently, we evaluated the effect of experimental chlorate product (ECP; 1x ECP is equivalent to a 15 mM chlorate ion concentration) during a 10-h pretransport FW. Market-age broilers were obtained from a commercial processing plant and randomly assigned to ECP-treated or control (nontreated) groups. Broilers were challenged by crop gavage with 10(8) Salmonella Typhimurium (ST) immediately upon arrival and 1 d prior to termination of the experiment. One day later, broilers were killed for ST enumeration (cfu) in the crop and ceca. Broilers provided ECP 24 h prior to slaughter consumed slightly more ECP water than broilers provided distilled water. Treatment with ECP caused a significant decrease (P < 0.05) in the incidence of ST in crop contents (2%) as compared to the controls (36.7%). Similarly, ECP treatment caused a significant decrease (P < 0.05) in number of ST (0.96 log10 ST/g cecal content) detected in the ceca when compared to controls (2.52 log10 ST). This study suggested that incorporation of ECP in the drinking water 24 to 48 h prior to slaughter could reduce Salmonella contamination in broilers.

Animals↗

PubMed2004

Immune modulation of the pulmonary hypertensive response to bacterial lipopolysaccharide (endotoxin) in broilers.

The lungs of broilers are constantly challenged with lipopolysaccharide (LPS, endotoxin) that can activate leukocytes and trigger thromboxane A2 (TxA2)- and serotonin (5HT)-mediated pulmonary vasoconstriction leading to pulmonary hypertension. Among broilers from a single genetic line, some individuals respond to LPS with large increases in pulmonary arterial pressure, whereas others fail to exhibit any response to the same supramaximal dose of LPS. This extreme variability in the pulmonary hypertensive response to LPS appears to reflect variability in the types or proportions of chemical mediators released by leukocytes. Our research has confirmed that TxA2 and 5HT are potent pulmonary vasoconstrictors in broilers and that broilers hatched and reared together consistently exhibit pulmonary hypertension after i.v. injections of TxA2 or 5HT. Previous in vitro studies conducted using macrophages from different lines of chickens demonstrated innate variability in the LPS-stimulated induction of nitric oxide synthase (iNOS) followed by the onset of an LPS-refractory state. The NOS enzyme converts arginine to citrulline and nitric oxide (NO). It is known that NO produced by endothelial NOS serves as a key modulator of flow-dependent pulmonary vasodilation, and it is likely that NO generated by iNOS also contributes to the pulmonary vasodilator response. Accordingly, it is our hypothesis that the pulmonary hypertensive response to LPS in broilers is minimal when more vasodilators (NO, prostacyclin) than vasoconstrictors (TxA2, 5HT) are generated during an LPS challenge. Indeed, inhibiting NO production through pharmacological blockade of NOS with the inhibitor Nomega-nitro-L-arginine methyl ester modestly increased the baseline pulmonary arterial pressure and dramatically increased the pulmonary hypertensive response to LPS in all broilers evaluated. Innate differences in the effect of LPS on the pulmonary vasculature may contribute to differences in susceptibility of broilers to pulmonary hypertension syndrome (ascites).

Animals↗

PubMed2005

Comparison of bruises and mortality, stress parameters, and meat quality in manually and mechanically caught broilers.

A field trial was conducted to compare manual catching of broilers with a mechanical catching method. Both methods were compared with respect to the incidence of bruises and dead on arrival, stress parameters, and meat quality. Also the dynamics of corticosterone, glucose, and lactate were investigated on the day broilers were killed. The broilers originated from 8 commercial broiler farms; visits were made on the day of catching during spring and autumn of 2001. Broilers of one house were caught manually, and those of the second house were caught mechanically. Plasma samples were taken before catching started, 30 min after the start of catching, 30 min before the end of catching, and at exsanguination of broilers from the first- and last-loaded transport vehicles. Postmortem measurements of pH, temperature, and water-holding capacity were made. Mechanical catching was associated with higher DOA percentages than manual catching in spring, although the difference was not significant in autumn. Catching method did not influence the percentage of bruises or meat quality. Moreover, corticosterone levels indicated that both methods induced the same amount of stress. The dynamics of corticosterone, glucose, and lactate levels showed a similar pattern. Plasma levels increased at the start of catching, and they further increased during transport, shackling, and stunning. However during catching itself, no large changes were observed. Our findings indicated that attempts to reduce stress in broilers during the last day of life could better be focused on factors other than catching.

Abattoirs↗

PubMed2006

Chemical treatments to reduce antinutritional factors in salseed (Shorea robusta) meal: effect on nutrient digestibility in colostomized hens and intact broilers.

This study investigated the effects of chemical treatments of salseed meal (SSM) on nutrient digestibility and digestive enzymes in colostomized hens and intact broilers. Finely ground SSM was treated (820 mL/ kg of SSM DM) with distilled water (pH 5.3), 0.67 M acetic acid (pH 2.4), or 0.67 M sodium hydrogen carbonate (pH 8.2), and incubated for 12 h at 37 degrees C. Five isonitrogenous and isocaloric diets each for colostomized hens (25.6 g of N/kg of DM and 12.5 MJ/kg of DM) and for broilers (33.6 g of N/kg of DM and 12.3 MJ/kg of DM) were formulated. For each group, 1 of these diets was wheat-based (control) whereas the other 4 were SSM-based diets (untreated SSM or SSM treated with water, acetic acid, and sodium bicarbonate). Inclusion of SSM in diets markedly reduced apparent protein and starch digestibility in hens and broilers. Chemical treatments of SSM improved the protein and starch digestibilities in colostomized hens and broilers. Treatment of SSM with alkali reduced the pancreatic hypertrophy in broilers that was observed when SSM was included in the diet. Inclusion of SSM in broiler diets did not affect pancreatic trypsinogen activity; however, chymotrypsinogen and alpha-amylase activities were depressed with its inclusion. Activities of these enzymes were improved by all chemical treatments of SSM. Dietary inclusion of SSM in broiler diets depressed the activities of trypsin, chymotrypsin, and alpha-amylase in the jejunal digesta. Alkali treatment proved to be the most effective in reducing the adverse effects of SSM upon trypsin and chymotrypsin activities. The hens receiving SSM in their diets produced eggs with discolored yolks (dirty greenish-yellow). In conclusion, nutrient digestibility, and pancreatic and intestinal enzymes were markedly depressed with the inclusion of SSM in the diets of the fowl. Bicarbonate was the most effective treatment to improve nutrient digestibility and mitigate, to some extent, the poor digestion of SSM.

Animal Feed↗

PubMed2006

Glycine supplementation to low protein, amino acid-supplemented diets supports optimal performance of broiler chicks.

Six experiments were conducted to determine the effects of low CP in diets for broilers and to evaluate limiting essential and nonessential amino acids (AA) in these diets. All experiments were conducted with Ross x Ross broilers in brooder batteries from 0 to 17 or 18 d posthatch. Treatments were replicated with 6 pens of either 5 or 6 broilers each. In Experiment (Exp.) 1, corn-soybean meal diets were formulated to 16.18, 17.68, 19.18, 20.68, or 22.18% CP. The 22.18% CP diet provided 1.23% Lys and 0.89% TSAA, met or exceeded all nutrient requirements of young broilers, and served as the positive control (PC) diet in all experiments. Increasing dietary CP linearly increased final BW, daily gain (ADG), and gain:feed (G:F) (P < 0.005). In Exp. 2, additions of crystalline essential (EAA) or nonessential AA (NEAA) were added to the low CP diet to simulate the AA profile of the PC. Daily gain, final BW, and G:F were decreased (P < 0.01) when CP was reduced, but the addition of the NEAA increased final BW, ADG, and G:F (P < 0.07) to the level of broilers fed the PC. Addition of EAA alone was without effect. In Exp. 3, chicks fed diets with supplemental Glu, Ala, Asp, or Pro had reduced daily feed intake (ADFI), ADG, and final BW (P < 0.05) compared with the PC diet. Addition of Gly or the combination of Gly, Glu, Asp, Ala, and Pro to the low CP diet increased G:F (P < 0.01) compared with chicks fed PC, and ADG was not different from that of broilers fed the PC diet. In Exp. 4, chicks were fed either the PC diet, the low CP diet with Gly + Ser concentrations of 1.23, 1.35, 1.47, 1.59, 1.71, 1.83, 1.95, or 2.07%, or a 10th diet that contained 1.23% Gly + Ser and with Glu to equal the N concentration of the 2.07% Gly + Ser diet. Final BW, ADG, and G:F were increased linearly (P < 0.001) as the concentration of dietary Gly + Ser was increased. Chicks fed the low CP diet with 2.07% Gly + Ser had growth performance that was not different from that of chicks fed the PC. The addition of Glu to the low CP diet was without effect. In Exp. 5, chicks were fed the PC with additions of 0, 0.15, or 0.30% Gly or the low CP diet containing 1.60, 1.72, 1.84, 1.96, 2.08, 2.20, or 2.32% Gly + Ser. Glycine addition to the PC had no effect, but Gly addition to the low CP diet increased G:F linearly (P < 0.001). Growth performance of chicks fed the low CP diet with 2.32% Gly + Ser was equal to that of chicks fed the PC diet. In Exp. 6, chicks were fed the PC or the low CP diet containing 1.80, 1.95, 2.10, 2.25, 2.40, 2.55, 2.70, 2.85, or 3.00% Gly + Ser. Glycine addition to the low CP diet increased G:F linearly (P < 0.001). In summary, low CP diets result in optimal growth of broilers with Gly + Ser levels of 2.44%.

Amino Acids↗

PubMed2006

Measurement of broiler litter production rates and nutrient content using recycled litter.

It is important for broiler producers to know litter production rates and litter nutrient content when developing nutrient management plans. Estimation of broiler litter production varies widely in the literature due to factors such as geographical region, type of housing, size of broiler produced, and number of flocks reared on the same litter. Published data for N, P, and K content are also highly variable. In addition, few data are available regarding the rate of production, characteristics, and nutrient content of caked litter (cake). In this study, 18 consecutive flocks of broilers were reared on the same litter in experimental pens under simulated commercial conditions. The mass of litter and cake produced was measured after each flock. Samples of all litter materials were analyzed for pH, moisture, N, P, and K. Average litter and cake moisture content were 26.4 and 46.9%, respectively. Significant variation in litter and cake nutrient content was observed and can largely be attributed to ambient temperature differences. Average litter, cake, and total litter (litter plus cake) production rates were 153.3, 74.8, and 228.2 g of dry litter material per kg of live broiler weight (g/kg) per flock, respectively. Significant variation in litter production rates among flocks was also observed. Cumulative litter, cake, and total litter production rates after 18 flocks were 170.3, 78.7, and 249.0 g/kg, respectively. The data produced from this research can be used by broiler producers to estimate broiler litter and cake production and the nutrient content of these materials.

Animal Feed↗

PubMed2006

Effect of dietary phosphorus, phytase, and 25-hydroxycholecalciferol on broiler chicken bone mineralization, litter phosphorus, and processing yields.

Three floor pen experiments (Exp) were conducted to evaluate low nonphytin P (NPP) concentrations and the NPP sparing effect of phytase (PHY) and 25-hydroxycholecalciferol (25D) on bone mineralization, bone breaking during commercial processing, litter P, and water-soluble P (WSP) concentrations. Tested treatments (TRT) were control, National Research Council NPP; University of Maryland (UMD) NPP; UMD + PHY, UMD NPP reduced by 0.064% NPP + 600 U of PHY/kg; UMD + PHY + 25D, UMD NPP reduced by 0.090% NPP + 600 U of PHY and 70 microg of 25D/kg; control + PHY mimicked the industry practice of diets by 0.1% when PHY is added; and negative control with 90% UMD NPP concentrations. UMD + PHY and control + PHY diets contained 600 U of PHY/kg, and UMD + PHY + 25D contained 600 U of PHY + 70 microg of 25D/kg. Performance results were presented separately. After each Exp, litter P and WSP were determined, and bone measurements were obtained on 8 or 10 broilers per pen. Tested TRT did not affect broiler BW. Femur ash weight of broilers fed the UMD and UMD + PHY + 25D was lower in all Exp compared with that of broilers fed the control diet. Femur ash was similar for control and UMD + PHY broilers, yet averaged over all Exp, UMD + PHY broilers consumed 39% less NPP and required less NPP per gram of femur ash than those on the control (4.87 and 7.77 g of NPP/g of ash, Exp 3). At the end of Exp 3, broilers were processed in a commercial facility. Despite reductions in NPP intake and bone mineralization, no differences were observed in measurements of economic importance (parts lost, carcass yield, and incidence of broken bones). The P excretion per bird was lowest for birds fed the UMD + PHY + 25D diet followed by those fed the UMD + PHY and negative control diets (10.44, 12.00, and 13.78 g of P/bird, respectively) and were highest for those fed the control diet (19.55 g of P/bird). These results suggest that feeding diets low in P together with PHY and 25D will not affect performance or increase losses at processing while resulting in improved P retention and reductions in P and WSP excreted.

6-Phytase↗

PubMed1997

Antimicrobial susceptibility patterns of thermophilic Campylobacter spp. from humans, pigs, cattle, and broilers in Denmark.

The MICs of 16 antimicrobial agents were determined for 202 Campylobacter jejuni isolates, 123 Campylobacter coli isolates, and 6 Campylobacter lari isolates from humans and food animals in Denmark. The C. jejuni isolates originated from humans (75), broilers (95), cattle (29), and pigs (3); the C. coli isolates originated from humans (7), broilers (17), and pigs (99); and the C. lari isolates originated from broilers (5) and cattle (1). All isolates were susceptible to apramycin, neomycin, and gentamicin. Only a few C. jejuni isolates were resistant to one or more antimicrobial agents. Resistance to tetracycline was more common among C. jejuni isolates from humans (11%) than among C. jejuni isolates from animals (0 to 2%). More resistance to streptomycin was found among C. jejuni isolates from cattle (10%) than among those from humans (4%) or broilers (1%). A greater proportion of C. coli than of C. jejuni isolates were resistant to the other antimicrobial agents tested. Isolates were in most cases either coresistant to tylosin, spiramycin, and erythromycin or susceptible to all three antibiotics. More macrolide-resistant isolates were observed among C. coli isolates from swine (79%) than among C. coli isolates from broilers (18%) and humans (14%). Twenty-four percent of C. coli isolates from pigs were resistant to enrofloxacin, whereas 29% of C. coli isolates from humans and none from broilers were resistant. More resistance to streptomycin was observed among C. coli isolates from swine (48%) than among C. coli isolates from broilers (6%) or humans (0%). The six C. lari isolates were susceptible to all antimicrobial agents except ampicillin and nalidixic acid. This study showed that antimicrobial resistance was found only at relatively low frequencies among C. jejuni and C. lari isolates. Among C. coli isolates, especially from swine, there was a high level of resistance to macrolides and streptomycin. Furthermore, this study showed differences in the resistance to antimicrobial agents among Campylobacter isolates of different origins.

Animals↗

PubMed2004

Effects of climate on incidence of Campylobacter spp. in humans and prevalence in broiler flocks in Denmark.

Campylobacter infections are increasing and pose a serious public health problem in Denmark. Infections in humans and broiler flocks show similar seasonality, suggesting that climate may play a role in infection. We examined the effects of temperature, precipitation, relative humidity, and hours of sunlight on Campylobacter incidence in humans and broiler flocks by using lag dependence functions, locally fitted linear models, and cross validation methods. For humans, the best model included average temperature and sunlight 4 weeks prior to infection; the maximum temperature lagged at 4 weeks was the best single predictor. For broilers, the average and maximum temperatures 3 weeks prior to slaughter gave the best estimate; the average temperature lagged at 3 weeks was the best single predictor. The combined effects of temperature and sunlight or the combined effects of temperature and relative humidity predicted the incidence in humans equally well. For broiler flock incidence these factors explained considerably less. Future research should focus on elements within the broiler environment that may be affected by climate, as well as the interaction of microclimatic factors on and around broiler farms. There is a need to quantify the contribution of broilers as a source of campylobacteriosis in humans and to further examine the effect of temperature on human incidence after this contribution is accounted for. Investigations should be conducted into food consumption and preparation practices and poultry sales that may vary by season.

Animals↗

PubMed2005

Bacteriophage therapy to reduce Campylobacter jejuni colonization of broiler chickens.

Colonization of broiler chickens by the enteric pathogen Campylobacter jejuni is widespread and difficult to prevent. Bacteriophage therapy is one possible means by which this colonization could be controlled, thus limiting the entry of campylobacters into the human food chain. Prior to evaluating the efficacy of phage therapy, experimental models of Campylobacter colonization of broiler chickens were established by using low-passage C. jejuni isolates HPC5 and GIIC8 from United Kingdom broiler flocks. The screening of 53 lytic bacteriophage isolates against a panel of 50 Campylobacter isolates from broiler chickens and 80 strains isolated after human infection identified two phage candidates with broad host lysis. These phages, CP8 and CP34, were orally administered in antacid suspension, at different dosages, to 25-day-old broiler chickens experimentally colonized with the C. jejuni broiler isolates. Phage treatment of C. jejuni-colonized birds resulted in Campylobacter counts falling between 0.5 and 5 log10 CFU/g of cecal contents compared to untreated controls over a 5-day period postadministration. These reductions were dependent on the phage-Campylobacter combination, the dose of phage applied, and the time elapsed after administration. Campylobacters resistant to bacteriophage infection were recovered from phage-treated chickens at a frequency of <4%. These resistant types were compromised in their ability to colonize experimental chickens and rapidly reverted to a phage-sensitive phenotype in vivo. The selection of appropriate phage and their dose optimization are key elements for the success of phage therapy to reduce campylobacters in broiler chickens.

Animals↗

PubMed2005

Reproduction of proventriculitis in commercial and specific-pathogen-free broiler chickens.

Proventriculitis was studied by experimentally reproducing the disease in broiler chickens. One-day-old infectious bursal disease virus (IBDV) and infectious bronchitis virus (IBV) antibody positive commercial broilers and 1-day-old antibody negative specific-pathogen-free (SPF) broilers were orally gavaged with proventricular homogenates produced from the proventriculi of broilers with proventriculitis. At 7 and 14 days, both commercial and SPF broilers had enlargement of the proventriculus with necrosis of the glandular epithelium and lymphocytic infiltrates in the proventricular glands. SPF broilers exposed to the proventricular homogenates developed infectious bursal disease, and IBDV was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). They also were positive by RT-PCR to IBV and developed nephritis. Commercial broilers developed mild nephritis but not bursal disease and were negative for IBDV and positive for IBV by RT-PCR. Both homogenate-inoculated commercial and SPF chickens were negative for reovirus and Newcastle disease virus by RT-PCR and variably positive for adenovirus by PCR. Bacteria were not identified in histologic sections, nor were they isolated from affected proventriculi. Indirect fluorescent antibody assay using convalescent sera detected intracytoplasmic staining in the proventricular glandular epithelial cells. Examination of thin sections of proventriculi using electron microscopy identified virus-like particles approximately 120 nm in diameter within the cytoplasm of these cells at 7 days after inoculation. Passage of proventricular homogenate filtrates in chicken embryos for virus isolation caused stunting, and allantoic fluid from these eggs was positive for IBV by RT-PCR.

Animals↗

PubMed1999

Emergence of Salmonella enteritidis outbreaks in broiler chickens in the Lebanon: epidemiological markers and competitive exclusion control.

This study investigates the first emergence of Salmonella Enteritidis outbreaks among chickens in the Lebanon and identifies the epidemiological markers of selected recovered Enteritidis strains. In addition, the authors evaluate a competitive exclusion approach to control infection in broiler chickens by Enteritidis organisms which possess the prevalent identified markers. The basic procedure in this investigation involved recording signs and lesions in eleven broiler chicken flocks on eleven farms, and culturing livers, spleens, and caeca of ten randomly selected birds per flock for Salmonella isolation and serotyping. Furthermore, culturing for Salmonella and serotyping was attempted from the livers, spleens, caeca and oviduct swabs of ten hens in four broiler breeder flocks which provided hatching eggs for the broilers under study. The identification of epidemiological markers in recovered S. Enteritidis included the determination of drug-resistance patterns and plasmid profiling. The competitive exclusion was evaluated by spraying the microflora on day-old broilers in the hatchery, followed by a controlled oral challenge at three days of age, with 2.85 x 10(5) colony-forming units of S. Enteritidis organisms per bird. Exclusion was evaluated by culturing for S. Enteritidis in anal swabs, spleens, livers, and caeca of individual challenged birds treated with the microflora and in untreated challenged birds. A total of 112 invasive S. Enteritidis strains were recovered on eleven farms from individual organs of broiler chickens with typical signs and lesions of salmonellosis. The prevalent resistance to drugs in such strains was to furaltadone and gentamycin, a marker identified in 93 strains (83%), recovered from nine out of eleven farms. The same resistance pattern was present in S. Enteritidis strains recovered from breeders on one out of four farms. The prevalent plasmid profile in nine S. Enteritidis organisms selected randomly from a pool of 93 strains (one per each of the nine broiler farms) was 14.1 kilobases (kb) and approximately 50.0 kb, a typical pattern to that identified in S. Enteritidis organisms recovered from oviducts of breeders on one out of four breeder farms. The exclusion significantly reduced cumulative mortality in birds of up to 45 days of age by 3.93%, in comparison to that observed in untreated challenged birds (P < 0.05). At 45 days of age, exclusion resulted in a 15.6% reduction in the percentage infection rate by S. Enteritidis in spleens or livers and a 34.4% reduction in the percentage infection rate of the caeca (P < 0.05).

Animals↗

PubMed2001

Epidemiologic features of Campylobacter jejuni isolated from poultry broiler houses and surrounding environments as determined by use of molecular strain typing.

OBJECTIVE: To genetically type Campylobacter jejuni isolates from broiler houses or the external environment to identify the source of Campylobacter organisms in broiler chickens. SAMPLE POPULATION: Environmental samples associated with broiler chickens, in commercial grow-out houses. PROCEDURE: Polymerase chain reaction (PCR) was used to amplify flaB, and the amplicon was digested with Sau3A to create a restriction fragment length polymorphism assay; PCR was also used to detect a transcribed spacer region in the 23S rRNA gene. RESULTS: Isolates possessing a 23S spacer region were more prevalent outside broiler houses than inside. Houses that had previously contained chickens or lacked biosecurity procedures were more likely to contain isolates possessing the 23S spacer. One house contained only isolates possessing the spacer, whereas an adjacent house contained only isolates lacking the spacer. The flaB type detected in broiler houses was different from the type detected in the environment; however, many isolates within the broiler houses contained untypable flaB genotypes. CONCLUSIONS AND CLINICAL RELEVANCE: Most isolates from within houses were genetically distinct from isolates from outside houses that were examined by bacteriologic culture, suggesting an undetected source of C jejuni. Detection of isolates containing the 23S spacer appeared to be an indicator of environmental contamination of the houses. The observation of completely different C jejuni genetic types simultaneously within adjacent houses suggests that some types do not compete successfully during the grow-out period. In addition, the diversity of genotypes identified within broiler houses indicates the complexity of the ecologic features of C jejuni in the chicken environment.

Animals↗

PubMed2006

Growth response of broilers to spray-dried plasma in pelleted or expanded feed processed at high temperature.

A series of 4 experiments evaluated effects of mash conditioning temperature from a pellet mill or expander on performance of broilers fed pelleted diets containing spray-dried plasma (SDP). All experiments utilized Ross x Ross 308 male broilers randomly assigned to their respective treatments (6 or 10 broilers/pen and 8 or 10 pens/treatment). Treatments in Exp. 1 consisted of a control (0% SDP), SDP coated postpelleting, or SDP blended into the meal prepelleting. Experiment 2 and 3 included the same 3 treatments as in Exp. 1 but with additional treatments of SDP blended into the meal and conditioned at 90 or 95 degrees C before pelleting. In Exp. 4, treatments consisted of a control (0% SDP) or SDP blended into the meal and pelleted (85 degrees C conditioning temperature) or expanded (149 degrees C final effective temperature) and then pelleted. Corn-soybean meal-based diets were formulated to be equal in lysine and ME in all experiments. Pelleted diets were conditioned for 15 s at 85 degrees C, and expanded diets were conditioned at 95 degrees C, 29.7 MJ/t, 13.95 kg/cm2 cone pressure, exit temperature of 149 degrees C, and then pelleted through a 4 x 32-mm die. In Exp. 1, ADG and feed intake were improved (P < 0.05) for broilers fed SDP from d 1 to 28 of age, with greater BW at d 42. In Exp. 2, both in early (d 1 to 28 of age) phases, and overall (d 1 to 42 of age), broilers fed SDP had improved (P < 0.05) gain and efficiency. In Exp. 3, ADG, feed intake, efficiency of gain, and BW were improved (P < 0.01) for broilers fed SDP from d 1 to 21 of age, regardless of conditioning temperature. In Exp. 4, broilers fed SDP had improved (P < 0.05) gain, BW, and feed intake regardless of processing method. Overall, the results of all of the experiments demonstrated that pellet conditioning temperature from 85 to 95 degrees C and expander temperatures to 149 degrees C did not impair the positive growth effects of SDP in pelleted or expanded broiler feed.

Animal Feed↗

PubMed1975

The effect of heat exposure and bacterial endotoxin on plasma zinc concentration and the body temperature in the broiler.

The effect of heat exposure and bacterial endotoxins on plasma zinc levels and mean rectal temperature of 8 week old broilers and investigated. Broilers exposed for 2 hours to 35-35 degrees C. had higher (P less than 0.01) mean rectal temperatures (42.8 vs 41.7 degrees C.) than sham treated broilers maintained at 22-24 degrees C. Likewise, endotoxin (E. coli, 500 mug./kg) treated broilers also had mean rectal temperatures significantly higher (P less than 0.01, 42.4 vs 41.7 degrees C.) than sham treated broilers. Plasma zinc levels in the bacterial endotoxin treated broilers were lower (P less than 0.05) than in the sham treated (173 vs 220, and 219 mug/kg./100 ml. plasma, respectively). In contrast, the plasma zinc concentration was not significantly depressed in the broilers exposed to heat for 2 hours. In summary, either endotoxin or heat exposure resulted in increased body temperature, however only the response to endotoxin resulted in a significant depression of plasma zinc concentration.

Animals↗