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PubMed2006

Effect of manganese source on manganese absorption by the intestine of broilers.

Two experiments were conducted to investigate the effect of Mn source on Mn absorption by the intestine of broilers. In Experiment 1, the effect of Mn source, including MnSO(4), 2 Mn-amino acid chelates (Mn-Gly and Mn-Met) synthesized in our laboratory, 3 Mn-amino acid complexes with different complex strengths (Mn-Met E, Mn-AA A, and Mn-AA B), and 2 mixtures of MnSO(4) with Gly or Met, on Mn absorption was assessed with ligated loops of different small intestinal segments of broilers. In Experiment 2, the absorption of Mn from MnSO(4), Mn-AA A, and Mn-AA B was compared with intact broilers fed ad libitum. The criterion used for comparison was the Mn content of hepatic portal vein plasma. The absorption of Mn was higher (P < 0.0002) by ligated ileal loops than by duodenal and jejunal ones. Met supplementation increased (P < 0.03) the absorption of Mn as MnSO(4). The absorption of Mn as Mn-AA A and Mn-AA B with moderate and strong complex strengths, respectively, were higher (P < 0.05) than those of Mn as MnSO(4) and Mn-Met E with weak complex strength. On d 7 and 9 of Experiment 2, the Mn content of portal vein plasma was higher (P < 0.03) for Mn-AA B with strong complex strength than for MnSO(4). On d 9, Mn content in plasma was higher (P < 0.01) for Mn-AA B with strong complex strength than for Mn-AA A with a moderate one. The results from this study confirm that the ileum was the main site of Mn absorption for broilers, and Met was more effective in facilitating Mn absorption than Gly as a ligand. Organic Mn was more efficiently absorbed than inorganic Mn (MnSO(4)); the absorption of organic Mn with moderate and strong complex strengths was greater than that of the organic Mn, which was weak, and the absorption of organic Mn with strong complex strength was greater than that of the organic Mn with a moderate strength.

Analysis of Variance↗

PubMed2006

Influence of a semiochemical analogue on growing performances and meat quality of broilers.

Stress in broilers may have severe consequences on the final product quality. A synthetic analogue of uropygial secretion of mother hens was isolated from poultry. This mother hen uropygial secretion analogue (MHUSA) was tested in farm conditions on broilers during 12 wk. The purpose of this trial was to estimate the influence of MHUSA on growing performances, meat characteristics after processing, and stress indicators of broilers. After the 80-d period, birds under treatment were heavier at 3 different weighing ages (P <or= 0.01, P <or= 0.01, and P <or= 0.05 at 21, 63, and 80 d of age, respectively) and had higher filet weights. A strong correlation between filet weight and carcass weight was found (R2 = 0.83). No correlation between abdominal fat and carcass weight or between abdominal fat and filet weight was observed. There was no significant difference among treatments concerning abdominal fat. Corticosterone level was higher for birds under placebo treatment (P <or= 0.05). No statistical difference was observed for mixed sexes concerning filet weight lost from 24 h to d 6 postmortem. After the cooking procedure, samples from the MHUSA group were less yellow compared with the control (P <or= 0.05). Our conclusion is that the tested semiochemical MHUSA has an influence on live weights, filet weights, and corticosterone levels in Label broilers grown to 80 d of age. Constant exposure to the MHUSA enhances growth without decreasing meat quality.

Aging↗

PubMed2006

Effect of beta-mannanase (Hemicell) on growth performance and immunity of broilers.

Two hundred four broilers (1-d-old) were randomly allocated to 4 treatments, each of which had 3 pens of 17 chicks per pen and were used to investigate the effects of beta-mannanase (Hemicell) on growth performance and immunity. The chicks received the same basal diet based on corn-soybean meal and Hemicell was added to the basal diet at 0, 0.025, 0.05, and 0.075%, respectively. Weight of each replicate was determined at wk 0, 3, and 6 of age. There were no significant differences in average feed intake in the 0- to 3-wk and 0- to 6-wk periods, and no differences in serum IgA, or IgG concentrations. However, the addition of Hemicell significantly increased (P < 0.05) weight gain in the 4- to 6-wk and 0- to 6-wk periods. Feed conversion for the 0.025 and 0.05% groups was significantly greater (P < 0.05) than for the control group in the 4- to 6-wk and 0- to 6-wk periods. Hemicell significantly increased (P < 0.05) the serum IgM concentration in 3- and 6-wk-old broilers. Proliferation of T lymphocytes in 6-wk-old broilers for the 0.05% group was also improved (P < 0.05) significantly. The results indicate that Hemicell may improve growth performance and immunity of broilers.

Animal Feed↗

PubMed2006

Genotyping of Campylobacter jejuni from broiler carcasses and slaughterhouse environment by amplified fragment length polymorphism.

We examined the occurrence and diversity of Campylobacter jejuni on broiler carcasses during slaughter of an infected flock and in the slaughterhouse environment during slaughter and postdisinfection before a new production run. During the slaughter of a known C. jejuni infected broiler flock, samples were taken from broiler carcasses at 7 different stages during the process. Thirty-seven sites in the slaughterhouse environment were sampled both during process and postdisinfection. The samples were analyzed for C. jejuni, and genetic fingerprinting was performed using amplified fragment length polymorphism. All carcass samples were positive. Of the environmental samples collected during slaughter, 89% were positive; 100% of those from the arrival, stunning, scalding, defeathering, and evisceration facilities and 67% of those from the cooling and sorting facilities. Postdisinfection, 41% of the samples were positive; 71% of those from the arrival and stunning area, 60% of those from the scalding and defeathering area, and 20% of those from the evisceration, cooling, and sorting area. The C. jejuni isolates (n = 60) recovered were grouped into 4 different amplified fragment length polymorphism clones with a similarity index of 95% or greater. All isolates obtained from the flock and 94% of the isolates obtained from the environment during slaughtering belonged to clone A, whereas 1 environmental isolate belonged to each of the clones B and C. Isolates from clones A, B, and D were present postdisinfection. Only clone B was detected on flocks slaughtered during the previous week. The high level and continuous presence of Campylobacter in the environment constitutes a risk for transmission to negative carcasses. In Norway, where above 96% of the broiler flocks are Campylobacter-negative, this aspect is of special importance. The ability of Campylobacter to remain in the slaughterhouse environment through washing and disinfection is associated with constructional conditions of equipment and buildings, complicating cleaning and providing sufficient moisture. To reduce the probability of the workers acquiring campylobacteriosis, precautions should be taken when slaughtering Campylobacter-positive flocks.

Abattoirs↗

PubMed2006

Evaluation of total plasma nitric oxide concentrations in broilers infused intravenously with sodium nitrite, lipopolysaccharide, aminoguanidine, and sodium nitroprusside.

Nitric oxide (NO) is a potent vasodilator that is synthesized by constitutive and inducible isoforms of the enzyme NO synthase (eNOS and iNOS, respectively). The half-life of NO averages only 3 to 4 s in biological fluids, where it is rapidly converted to the stable oxidation products nitrite (NO2-) and nitrate (NO3-). Our objectives were to use 2 commercial kits to measure total plasma NO, as NO2- + NO3-, and to assess plasma NO values during experimental protocols designed to influence NO accumulation in the plasma. One kit employed copper-coated cadmium as a catalyst for reducing NO3- to NO2-; the second kit employed the enzyme NO3- reductase for the same purpose. Both then employed Griess reagent for the colorimetric determination of NO2- as a measure of total plasma NO. Broilers in Experiment 1 were infused i.v. with solutions containing increasing concentrations of sodium NO2-. Broilers in Experiment 2 were injected with 1 mg of lipopolysaccharide (LPS), which is known to stimulate iNOS activity. Both commercial kits successfully detected increases in total plasma NO attributable to ongoing i.v. NO2- infusion or to increased iNOS expression at 5 h after the LPS injection. In Experiment 3, we compared the total plasma NO responses to LPS in the presence and absence of aminoguanidine (AG), a selective inhibitor of iNOS. The AG significantly attenuated the LPS-mediated increase in total plasma NO at 5 h post-injection. In Experiment 4, broilers were infused with sodium nitroprusside (SNP), an exogenous NO donor molecule that previously had been shown to lower the pulmonary arterial pressure in broilers. The SNP infusion did substantially reduce the pulmonary arterial pressure, but an increase in total plasma NO was not detected during the SNP infusion. Overall, NO accumulation in the plasma was successfully detected after sustained infusion of NaNO2 and administration of LPS for 5 h, but biologically effective levels of NO released from SNP were not detected. Therefore, total plasma NO concentrations (assayed as NO2- + NO3-) qualitatively reflect whole-body NO synthesis, but biologically relevant quantities of NO may be produced at levels that cannot be detected by colorimetric assays.

Animals↗

PubMed2006

The effects of phytase on growth performance and intestinal transit time of broilers fed nutritionally adequate diets and diets deficient in calcium and phosphorus.

Five experiments (Exp.) were conducted to determine the effects of phytase on growth performance and intestinal transit time in chicks fed nutritionally adequate diets and diets deficient in Ca and nonphytate P (nPP). In Exp. 1 and 2, chicks were fed a nutritionally adequate diet from 0 to 6 d or from 0 to 4 d posthatching; assay periods were 8 or 10 d; average initial BW were 98 or 79 g; and average final BW were 371 or 369 g, respectively. Treatments were replicated with 12 pens of 5 chicks each. Corn-soybean meal (C-SBM) diets were adequate in all nutrients except Ca and nPP where appropriate. The treatments were 1) C-SBM, 1.0% Ca, and 0.45% nPP; 2) C-SBM, 0.80% Ca, and 0.25% nPP; 3) Diet 1 + 600 phytase units/kg of diet; 4) Diet 2 + 600 phytase units/kg of diet. Experiments 3, 4, and 5 were conducted to determine the effects of phytase on intestinal transit time in broilers. Broilers were fed the same nutritionally adequate diet from 0 to 18, 27, or 23 d posthatching, and the assay periods were 7 d. Treatments were replicated with 18 individually penned broilers. Average initial BW were 768, 1,108, or 838 g, and average final BW were 1,299, 1,704, or 1,392 g in Exp. 3 to 5, respectively. Transit time data were collected on d 1 and 7 of the Exp. Diets were 1) C-SBM, 0.9% Ca, and 0.35% nPP; 2) C-SBM, 0.80% Ca, and 0.25% nPP + 600 phytase units/kg of diet. Transit time was calculated as the difference between the time feed was first ingested and the time of first appearance of solid feces. In Exp. 1 and 2, the reduction in dietary Ca and nPP reduced (P < 0.01) average daily gain (ADG), average daily feed intake (ADFI), and gain:feed. Phytase addition increased (P < 0.02) ADG and ADFI in diets deficient in Ca and nPP and in the nutritionally adequate diets. In Exp. 2, the reduction in Ca and nPP reduced (P < 0.01) toe and tibia ash percentage, but phytase addition increased (P < 0.01) toe and tibia ash percentage. The increase in toe ash percentage was greater in chicks fed the Ca and nPP deficient diet than in chicks fed the nutritionally adequate diet (Ca and nPP x phytase, P < 0.01). In Exp. 3, 4, and 5, transit time on d 1 was faster (P < 0.03) in chicks fed phytase. On d 7, transit time tended to be faster in chicks fed phytase, but the effect was not significant (P = 0.15). These data indicate that phytase increases ADG and ADFI in diets deficient in Ca and nPP and in diets formulated to be adequate (or excess) in all nutrients for broiler chicks. The increase in ADG and ADFI in chicks fed the nutritionally adequate diet may be due to a faster transit time of feed through the digestive tract, resulting in a greater feed intake and gain.

6-Phytase↗

PubMed2006

Enumeration and identity of Campylobacter spp. in Italian broilers.

Transmission of Campylobacter to humans has been prominently associated with mishandling or improperly preparing contaminated poultry carcasses. The number of organisms per carcass represents an important measure of human exposure to the agent. Therefore, we wished to estimate this public exposure over 1 yr among Italian broiler carcasses. We sampled 213 broiler carcasses from rinse water samples collected from a single slaughterhouse. Groups of carcasses had mean processed weights ranging from 1.2 to 2.7 kg. These were produced from 22 commercial broiler chicken flocks collected from 12 different farms, 3 of which were seasonally tested. Carcasses were rinsed with sterile water, and the rinse suspension was then serially diluted and spread-plated directly onto Campy-Cefex agar plates. One to 5 typical Campylobacter colonies per plate were identified by polymerase chain reaction as Campylobacter thermo-tolerant species. The overall estimated mean count per carcass in our study was 5.16 +/- 0.80 log10 cfu. This value increased in summer and autumn, as well as on carcasses collected from farms located > 100 km far from the slaughterhouse. A total of 678 Campylobacter colonies were identified by polymerase chain reaction. The majority of isolates were classified as Campylobacter jejuni (49.2%) or Campylobacter coli (47.5%). The overall number of C. jejuni was significantly higher on 1) carcasses weighing > 2 kg, 2) carcasses belonging to flocks with > 10,000 birds, and 3) carcasses collected from farms located > 100 km from the slaughterhouse. Moreover, among farms tested seasonally, C. jejuni was significantly greater than C. coli in winter. These data provide the first results of a continuing survey on Campylobacter loads and species identification from Italian broiler carcasses and represents an important baseline to estimate the human exposure to Campylobacter in Italy.

Abattoirs↗

PubMed2006

Diet-induced thermogenesis and glucose oxidation in broiler chickens: influence of genotype and diet composition.

The main objectives of this study were to explore the role of diet-induced thermogenesis in the regulation of voluntary feed intake and to determine the glucose oxidation of broiler chicken strains, known to differ in glucose-insulin balance. From 2 to 7 wk of age, male broiler chickens of a fat and a lean line were reared on 1 of 2 isoenergetic diets with constant gross energy and carbohydrate levels but with substitutions between fat and protein. The low protein (LP/HF) diet contained 126 g of protein/kg and 106 g of fat/kg, whereas the low fat (LF/HP) diet contained 242 g of protein/kg and 43 g of fat/kg. There was no significant effect of the genetic background of the broilers on the glucose oxidation rate (as measured by stable isotope breath test) or protein oxidation (as measured by plasma uric acid levels). Considering the difference in carcass composition (fat content) of both lines, this leads to the hypothesis that the lines differ predominantly in fat metabolism. Although there was no line effect on plasma triglyceride and free fatty acid concentrations, it was hypothesized that there might be differences in fat oxidation or de novo lipogenesis, or both, between the genotypes. Diet-induced thermogenesis per metabolic body weight (kg of BW0.75) per 24 h, expressed per gram of feed intake, was not significantly influenced by genetic background or by diet composition. Therefore, a model linking feed intake to diet-induced thermogenesis, as postulated for adult mammals, could not be corroborated for growing broiler chickens.

Adipose Tissue↗

PubMed2006

Broiler short-term feed preferences measured with SRAbox, a new feed choice procedure.

Three dietary compositions and 3 methods of pellet preparation were used in different choice situations to improve our understanding of the factors perceived by broiler chickens in the physical structure of their diet. Within the same visual field, broiler chickens were offered 8 microfeeders containing different pelleted feeds that could be reached from the same position of the bird. Chickens were daily tested during 5-min tests following a 45-min period of feed withdrawal, after adaptation to individual cages and experimental feeders. Two feeds (4 microfeeders/feed in alternate positions) were weighed prior to and after the test. Behavior of the chickens was videotaped during the test to count the number of pecks given to each microfeeder. In a first experiment, 2 feeds of distinct composition were either steam or cold-pelleted. The tests of choice were repeated daily from 22 to 25 and from 35 to 38 d of age on 96 male broiler chickens. Significant preferences were measured from the first test. Similar preferences were measured when chickens received the same choice or alternating choices from one test to another. Differences of feed intake between 2 feeds during 5 min were significantly correlated to differences of number of pecks (R2 = 0.85). In most cases, preferences were established within the first minute of pecking. Steam pellets were significantly preferred to cold pellets for one feed composition but not for the other. Preferences for compositions were consistent whatever the pellet preparation and probably associated with the color of the feeds. A second experiment confirmed that 38-d-old broiler chickens seemed to prefer light colors. Short-term preferences of a chicken for a feed were rather influenced by physical characteristics of feed particles (size, color, hardness) than by the origin of raw materials. Feed pecking may change because of feed composition itself, because of its consequences on color or texture cues, or both.

Animal Feed↗

PubMed2006

Microbial community composition of the ileum and cecum of broiler chickens as revealed by molecular and culture-based techniques.

The microbial communities of the ileum and cecum of broiler chickens from a conventional and an organic farm were investigated using conventional culture techniques as well as cloning and sequencing of 16S rRNA genes. Eighty-five percent of the 557 cloned sequences were <97% related to known cultured species. The chicken ileum was dominated by lactobacilli, whereas the cecum harbored a more diverse microbial community. The cecum was dominated by a large group of bacteria with hitherto no close cultured relatives but most closely related to Faecalibacterium prausnitzii. Approximately 49 and 20% of the cecal clones belonged to this cluster in conventional and organic broiler chickens, respectively. We were, however, able to recover a number of these phylotypes by cultivation, and the isolates were shown to be butyric acid producers. The investigation was a descriptive rather than a comparative study of 2 different rearing systems; however, several differences were observed. For instance, Clostridium perfringens was found in significantly higher numbers in the birds from the organic farm compared with the conventional broilers, probably due to the addition of salinomycin to the conventional feed. In the ileum, the abundance of the different Lactobacillus species differed between the 2 broiler types. The culture-based and culture-independent techniques complemented each other well. Strengths and limitations of the different methods are discussed.

Animal Feed↗

PubMed2006

Detection of Campylobacter jejuni in various lymphoid organs of broiler breeder hens after oral or intravaginal inoculation.

Two studies were conducted to determine whether Campylobacter jejuni could rapidly spread and reside in the internal organs of adult broiler breeder hens. In Study 1, university-housed broiler breeders at 22 wk of age were obtained and placed in individual cages. Each hen was intravaginally inoculated weekly from 23 to 32 wk of age with a characterized strain of C. jejuni. At wk 23, 27, and 32, 4 d postinoculation, the hens were euthanized, defeathered, and aseptically opened. In Study 2, university-housed broiler breeder hens were obtained at 42, 53, and 56 wk of age, placed in individual cages, and inoculated either orally or intravaginally with a characterized strain of C. jejuni. To reduce the possibility of cross-contamination among samples, the thymus, spleen, liver, and gallbladder were aseptically removed, prior to the ceca. In both studies, all samples were individually analyzed. In Study 1, at 23 wk of age, C. jejuni was recovered from 4/7 thymii, 2/7 spleens, 5/7 livers and gallbladders, and 6/7 ceca. At 27 wk of age, C. jejuni was recovered from 1/7 thymii and 1/7 ceca. At 32 wk of age, C. jejuni was recovered from 4/11 thymii, 1/11 livers and gallbladders, and 2/11 ceca. In Study 2, C. jejuni was recovered from 2/6 thymii and 5/6 ceca after oral inoculation and 1/6 spleens, 1/6 livers and gallbladders, and 4/6 ceca after vaginal inoculation of 43-wk-old hens. Campylobacter jejuni was recovered from 2/5 thymii, 3/5 spleens, 3/5 livers and gallbladders, and 2/5 ceca after oral inoculation of 53-wk-old hens and 1/5 thymii and 1/5 livers and gallbladders after vaginal inoculation. Campylobacter jejuni was recovered from 1/4 thymii, 2/4 livers and gallbladders, and 1/4 ceca and was not detected in any vaginally inoculated birds of 57-wk-old hens. This study provides evidence that C. jejuni can reside in the internal organs of broiler breeder hens following oral or intravaginal inoculation.

Administration, Intravaginal↗

PubMed2006

Effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance and metabolism of broiler breeders.

A study was conducted to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance and metabolism of broiler breeders. Forty-two 26-wk-old broiler breeder hens and nine 26-wk-old roosters were fed the following diets: (1) control, (2) contaminated grains, and (3) contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent (GMA) for 12 wk. The major contaminant was deoxynivalenol (12.6 mg/kg of feed), with lesser amounts of zearalenone and 15-acetyl-deoxynivalenol. Feed consumption and BW were not affected by diet. The feeding of contaminated grains did not significantly affect egg production. Decreased eggshell thickness was seen, however, at the end of wk 4, and dietary supplementation with GMA prevented this effect. There was no effect of diet on other egg parameters measured. There was a significant increase in early (1 to 7 d) embryonic mortality in eggs from birds fed contaminated grains at wk 4, but mid- (8 to 14 d) and late- (15 to 21 d) embryonic mortalities were not affected by diet. There were no differences in newly hatched chick weights or viability. The ratio of chick weight to egg weight was not affected by the feeding of contaminated grains. Weight gains of chicks fed a standard broiler starter diet at 7, 14, and 21 d of age were not significantly affected by previous dietary treatments for the dam. It was found that rooster semen volume and sperm concentration, viability, and motility were not affected by the feeding of contaminated diets. There was no effect of diet on the relative weights of liver, spleen, kidney, and testes. The feeding of contaminated grains decreased antibody titers against infectious bronchitis virus at the end of wk 12, and this was prevented by dietary supplementation with GMA. There was no effect of the diet on serum antibody titers against Newcastle disease virus. It was concluded that the feeding of blends of grains contaminated with Fusarium mycotoxins could affect performance and immunity in broiler breeder hens.

Animal Feed↗

PubMed2006

Association of twelve immune-related genes with performance of three broiler lines in two different hygiene environments.

Elite populations of farm animals under genetic selection are often maintained in high hygiene conditions, yet the commercial populations may be raised in, and are expected to perform well in, environments of varied hygiene levels. This presents special challenges to genetically improve those traits for which genotype by environment interactions are important. Twelve immune-related genes were studied for associations with general mortality and other performance traits in 3 elite commercial broiler chicken lines raised in high and low hygiene environments. The genes were toll-like receptor 4, MD-2 (accessory' protein of TLR4), interferon-gamma, transforming growth factor-beta3, inducible nitric oxide synthase, macrophage migration inhibitory factor, interleukin-2, caspase-1, inhibitor of apoptosis protein-1, tumor necrosis factor-related apoptosis-inducing ligand, chicken B-cell marker, and bone morphogenetic protein-7. From a total of 56 identified single-nucleotide polymorphisms (SNP) in 12 genes, 14 SNP that had moderate allelic frequencies in at least 2 of the 3 lines were typed in about 100 progeny-tested sires from each of 3 elite commercial broiler chicken lines using restriction fragment length polymorphism techniques and then used in association analysis. The traits measured on the progeny (total progeny = 145,467) were: mortality from hatching to 14 d and from 14 to 40 d of age, BW at 7 and 40 d of age, feed conversion, ultrasound breast depth, percentage of breast, eviscerated carcass weight, twisted legs or evident tibial dyschondroplasia, x-ray-inspection-based subclinical or incipient development of tibial dyschondroplasia, curly or crooked toes or bowed legs, oxygen content of blood, and female's antibody titer to infectious bursal disease virus at 27 wk. Association analyses were conducted with allele and haplotype substitution effect models using progeny mean data adjusted for fixed and mate effects as sire trait records. Ten of the 12 genes had SNP associations with at least 1 trait. Most detected effects were with mortality and growth traits. Most gene-SNP trait associations varied by genetic line or with environment. These results indicate that associations of candidate genes with important broiler traits can be identified in multiple environments, and they offer a potential for the implementation of marker-assisted selection for traits expressed in the environment in which the commercial broiler needs to perform. The effects of these immune-related candidate genes, however, are complex and affected by genetic background and environment.

Animal Husbandry↗

PubMed2007

The feeding dynamics of broiler chickens.

Contrary to a commonly held belief that broiler chickens need more space, there is increasing evidence that these birds are attracted to other birds. Indeed, commercially farmed birds exhibit a range of socially facilitated behaviours, such as increased feeding and preening in response to the presence of other birds. Social facilitation can generate feedback loops, whereby the adoption of a particular behaviour can spread rapidly and suddenly through the population. Here, by measuring the rate at which broiler chickens join and leave a feeding trough as a function of the number of birds already there, we quantify social facilitation. We use these measurements to parameterize a simulation model of chicken feeding behaviour. This model predicts, and further observations of broiler chickens confirm, that social facilitation leads to excitatory and synchronized patterns of group feeding. Such models could prove a powerful tool in understanding how feeding patterns depend on broiler house design.

Animal Feed↗

PubMed2002

A probabilistic transmission model of Salmonella in the primary broiler production chain.

Annual data from the Finnish National Salmonella Control Programme were used to build up a probabilistic transmission model of salmonella in the primary broiler production chain. The data set consisted of information on grandparent, parent, and broiler flock populations. A probabilistic model was developed to describe the unknown true prevalences, vertical and horizontal transmissions, as well as the dynamical model of infections. By combining these with the observed data, the posterior probability distributions of the unknown parameters and variables could be derived. Predictive distributions were derived for the true number of infected broiler flocks under the adopted intervention scheme and these were compared with the predictions under no intervention. With the model, the effect of the intervention used in the programme, i.e., eliminating salmonella positive breeding flocks, could be quantitatively assessed. The 95% probability interval of the posterior predictive distribution for (broiler) flock prevalence under current (1999) situation was [1.3%-17.4%] (no intervention), and [0.9%-5.8%] (with intervention). In the scenario of one infected grandparent flock, these were [2.8%-43.1%] and [1.0%-5.9%], respectively. Computations were performed using WinBUGS and Matlab softwares.

Animals↗

PubMedDate not supplied

Effects of different phosphorus sources in the diet on bone composition and stability (breaking strength) in broilers.

In two fattening trials (in each 100 broilers kept in four groups with 25 animals) as well as in a balance trial (four groups with four broilers in a group) the effects of inorganic phosphorus sources [monocalcium phosphate (MCP), dicalcium phosphate (dihydrate; DCP) and defluorinated phosphate (DFP)] in broiler diets were examined. The four diets contained up to 9 g calcium and 6 g phosphorus per kg and comparable energy and nutrient contents. Controls were fed a commercial diet with Ca-Na-phosphate as inorganic phosphorus source supplemented by phytase. In both fattening trials body weight gain, feed consumption and feed conversion were proved as well as the calcium and phosphorus levels in serum, the breaking strength of tibia or humerus and the femur mineralization (ash content in the fat free dry matter). Furthermore, in the balance trial the retention of calcium and phosphorus was determined by calculation (intake minus excretion) as well as by analysis of body composition. On a high performance level (that was only slightly influenced by the different treatments), the addition of DFP resulted in significantly reduced phosphorus availability (estimated by analysis of the whole carcass: control/MCP/DCP/DFP: 48.6/46.0/45.7/35.5%). The significantly reduced phosphorus level in serum (1.77 +/- 0.20/1.77 +/- 0.24/1.73 +/- 0.28 1.34 +/- 0.33 mmol/l) indicates the lower phosphorus retention in broilers given DFP. Furthermore, the crude ash content (582 +/- 17.6/580 +/- 18.6/563 +/- 15.2/547 +/- 29.7 g/kg fat free DM) and the breaking strength of bones (in right tibia in trial 2: 232 +/- 82.4/227 +/- 51.5/232 +/- 41.7/196 +/- 655 N) were lowest when given DFP. For diagnostic purposes it is of special interest that the phosphorus levels in the serum reflected markedly the different concentrations of available phosphorus in the diet.

Animal Feed↗

PubMed2004

Some potential sources for transmission of Campylobacter jejuni to broiler chickens.

AIMS: The aim of the study was to determine Campylobacter jejuni contamination and prevalence on fomites moving between broiler farms and the processing plant in the period after cleaning and before departure to harvest chickens. In addition, changes in the proportion of contaminated fomites in the course of a day were assessed. METHODS AND RESULTS: Pooled swab samples were obtained from pallets, crates, wheels of trucks, tractors and forklifts, truck beds, and from drivers' and catchers' boots. After enrichment in Bolton's broth Campylobacter were recovered on modified blood-free Campylobacter selective agar (mCCDA). Isolates were identified using tests for phenotypic and biochemical characteristics. Of the 209 samples collected, 53% were positive for C. jejuni, with all fomites positive except tractor wheels. Pallets had the highest contamination rate at 75%. More than 50% of catchers' boots, drivers' boots, crates and truck wheels were positive. Forty-seven per cent and 31% of truck beds and forklift wheels, respectively, were contaminated. The proportion of contaminated fomites did not change significantly during the day. CONCLUSIONS: This study has identified trucks, forklifts, pallets, crates, drivers' and catchers' boots as potential sources of C. jejuni for broilers. SIGNIFICANCE AND IMPACT OF THE STUDY: Campylobacter jejuni contamination of broiler processing plant fomites was found to be extensive ranging from 31% for truck beds to 75% for pallets. The proportion of contaminated fomites was observed to be similar throughout the day. The impact of contaminated fomites as sources of colonization of broilers with C. jejuni is discussed.

Animals↗

PubMed2004

Longitudinal study of Campylobacter jejuni bacteriophages and their hosts from broiler chickens.

A longitudinal study of bacteriophages and their hosts was carried out at a broiler house that had been identified as having a population of Campylobacter-specific bacteriophages. Cloacal and excreta samples were collected from three successive broiler flocks reared in the same barn. Campylobacter jejuni was isolated from each flock, whereas bacteriophages could be isolated from flocks 1 and 2 but were not isolated from flock 3. The bacteriophages isolated from flocks 1 and 2 were closely related to each other in terms of host range, morphology, genome size, and genetic content. All Campylobacter isolates from flock 1 were genotypically indistinguishable by pulsed-field gel electrophoresis (PFGE). PFGE and multilocus sequence typing indicated that this C. jejuni type was maintained from flock 1 to flock 2 but was largely superseded by three genetically distinct C. jejuni types insensitive to the resident bacteriophages. All isolates from the third batch of birds were insensitive to bacteriophages and genotypically distinct. These results are significant because this is the first study of an environmental population of C. jejuni bacteriophages and their influence on the Campylobacter populations of broiler house chickens. The role of developing bacteriophage resistance was investigated as this is a possible obstacle to the use of bacteriophage therapy to reduce the numbers of campylobacters in chickens. In this broiler house succession was largely due to incursion of new genotypes rather than to de novo development of resistance.

Animals↗