Pathological features in dead on arrival broilers with special reference to heart disorders

Data evaluation of broiler chicken rearing and slaughter-An exploratory study

To process and evaluate the data from broiler fattening and slaughtering, we investigated the production data of 107 straight run flocks of the commercial meat-type breed Ross 308 (Aviagen, EU). All flocks were raised and slaughtered in Germany and the average slaughter age was 37 days. The health outcomes of interest were mortality, average weight, and the slaughter results. First-week mortality, cumulative mortality, stocking density, flock size, season, production week of the parental flock, farm, antibiotic treatment, and the interaction between antibiotic treatment and season were considered as possible influencing factors. The average first-week mortality (FWM) and cumulative mortality percentages were 0.66 and 2.74%, respectively. First-week mortality was influenced by flock size, production week of the parental flock, and the interaction between antibiotic treatment and season, whereas cumulative mortality was influenced by antibiotic treatment, farm, and first-week mortality. The average weight (mean 2.30 kg) was influenced by season, stocking density, flock size, farm, and the interaction between antibiotic treatment and season. The condemnation rate was on average 1.48%, with the most common causes being deep dermatitis (mean 0.63%), ascites (mean 0.53%), and not suitable for production/general disease (mean 0.25%). Several factors influenced the causes of condemnation, with season being the most predominant one, followed by the interaction between antibiotic treatment and season, the antibiotic treatment alone, and stocking density.

Role of Corticosterone in Lipid Metabolism in Broiler Chick White Adipose Tissue

Excessive accumulation of body fat in broiler chickens has become a serious problem in the poultry industry. However, the molecular mechanism of triglyceride accumulation in chicken white adipose tissue (WAT) has not been elucidated. In the present study, we investigated the physiological importance of the catabolic hormone corticosterone, the major glucocorticoid in chickens, in the regulation of chicken WAT lipid metabolism. We first examined the effects of fasting on the mRNA levels of lipid metabolism-related genes associated with WAT, plasma corticosterone, and non-esterified fatty acid (NEFA). We then examined the effects of corticosterone on the expression of these genes in vivo and in vitro. In 10-day-old chicks, 3 h of fasting significantly decreased mRNA levels of lipoprotein lipase (LPL) in WAT and significantly elevated plasma concentrations of NEFA. Six hours of fasting significantly increased mRNA levels of adipose triglyceride lipase (ATGL) in WAT and significantly elevated plasma concentrations of corticosterone. On the other hand, fasting significantly reduced mRNA levels of LPL in WAT and elevated plasma concentrations of NEFA in 29-day-old chicks without affecting mRNA levels of ATGL in WAT or plasma corticosterone concentrations. Oral administration of corticosterone significantly reduced mRNA levels of LPL and significantly increased the mRNA levels of ATGL in WAT in 29-day-old chicks without affecting plasma NEFA concentrations. The addition of corticosterone to primary chicken adipocytes significantly increased mRNA levels of ATGL, whereas mRNA levels of LPL tended to decrease. NEFA concentrations in the culture medium were not influenced by corticosterone levels. These results suggest that plasma corticosterone partly regulates the gene expression of lipid metabolism-related genes in chicken WAT and this regulation is different from the acute elevation of plasma NEFA due to short-term fasting.

The welfare impacts of mechanical and manual broiler catching and of circumstances at loading under field conditions

Loading of broilers for transport to the processing plant poses a notable injury risk for broilers. Therefore, the poultry industry has developed mechanical methods as alternatives to manual loading methods. Our objective in the present study was to compare manual loading (MAN) of broilers with the mechanical loading (MECH). We assessed the injuries of broilers of 12 MAN and 12 MECH flocks on-farm before and immediately after loading, documented the numbers of broilers dead on arrival reported by the processing plant, and assessed the circumstances at loading. A smaller number of broilers with a hematoma (≥0.5 cm in diameter) on the wing were observed after MAN compared with MECH using the examined harvester (MAN vs. MECH odds ratio: 0.16; 95% confidence interval: 0.10, 0.28). The number of broilers with severe wing injuries did not differ between the loading methods. The number of broilers dead on arrival was greater in mechanically loaded flocks (MAN vs. MECH odds ratio: 0.26; 95% confidence interval: 0.10, 0.68), but lower than in comparable studies. We observed a lower average stocking rate than targeted in the drawers of MECH containers, most likely because the used harvester can adapt to short-term changes in weight and adjust the stocking rate during the loading process. A longer total loading duration in MAN was associated with an increase of wing hematomas, and the involvement of more working people per 10,000 broilers during MAN was associated with a lower occurrence of hematomas. The total loading duration in MECH had no notable influence on the occurrence of injuries. Physical conditions of the involved personnel might play a larger role in MAN than in MECH. The harvester that was examined should be further developed to reduce the occurrence of hematomas. Our results indicate that the choice of loading method alone does not determine the injury risk, and multiple factors are associated with broiler welfare during loading. It is important that the chosen method is performed under the most adequate conditions.

Risk factors for poor health and performance in European broiler production systems

BACKGROUND

Conventional broilers are currently one of the most efficient protein converters. Although decades of progress in genetic selection and feed formulation have lead to high standards of efficient broiler production, still a lot of variability is found between farms and between successive flocks. The aim of this study was to investigate risk- and/or protective factors for poor health and performance in conventional broiler-farms in Europe by developing eight multivariable linear mixed models. Three different models were used to investigate mortality (overall, first week, after first week), three models for performance variables (growth, feed conversion, European production index) and two models were related to slaughterhouse data (i.e. dead on arrival and condemnation rate).

RESULTS

Several factors related to management and housing were significantly associated with health and performance of broilers. The following factors were associated with increased mortality: floor quality, neonatal septicemia, ventilation type and other professional activities of the farmer. The factors associated with performance were chick sex, coccidiosis infections, necrotic enteritis, dysbacteriosis, light intensity adaptations, ventilation type, comparing daily flock results with previous flock results by farmer, daily check of feed and water system and type of feed. For dead on arrival three risk factors were identified i.e. daily growth, type of light adaptation and type of drinkers system. For condemnation rate seven risk factors were found, i.e. type of drinking system, daily growth, feed withdrawal time, type of ventilation, house size, septicemia after seven days and type of feed.

CONCLUSIONS

These results imply that a multifactorial approach is required with adaptations involving both improvements in management, housing, health programs and an increasing level of professionalism of the farmer in order to improve broiler performance and health.

A combined retrospective, prospective and experimental study of Ornithobacterium rhinotracheale infection in chickens

The aim of this study was to examine the histopathological and immunohistochemical changes caused by natural and experimentally-induced Ornithobacterium rhinotracheale infection in the respiratory system of chickens. To this end, three different studies were carried out. The first was a retrospective study of 82 field cases with respiratory disorders compatible with O. rhinotracheale infection. The bacterium was immunohistochemically detected in the lungs in 48 of 82 field cases, and 50 β-haemolytic (BH) and non-haemolytic (NH) strains were isolated. In the second study, an experimental model of the disease was created using 3-week-old broiler chickens, to identify possible differences of pathogenicity between the BH and NH isolates by the intravenous (IV) and intratracheal (IT) inoculation routes (IR). The group challenged with the NH isolate showed more severe lung lesions than the group challenged with the BH isolate at 7-days postinoculation (p.i.). The 14-day p.i. groups challenged with either the BH or NH isolates by the IT or IV IR had a higher histologic grade of pulmonary and hepatic lesions and a higher total histologic grade of lesions suggesting more severe pathology with longer time of exposure. A direct association between the inoculation routes and the organs affected was shown. Finally, a slaughterhouse study was carried out from October 2014 to May 2015, in which the histologic grade of lesions was significantly higher in immunohistochemically positive for O. rhinotracheale lungs of dead-on-arrival chickens.

Risk factors for bruising and mortality of broilers during manual handling, module loading, transport, and lairage

Multiple factors can affect the risk of bruising and mortality of broilers during loading, transport, and lairage. The risk factors affecting the percentages of broilers in each load that were “dead-on-arrival” (DOA) or bruised were studied from records provided by a processing plant, by undertaking direct observations during on-farm loading and then carrying out multivariable analyses. Selected loads between 2014 and 2015 from seven producers were included in the study. The median DOA per load was 0.13% (Q1 = 0.06, Q3 = 0.25, n = 212), the median total duration from loading to unloading was 8.6 h, and the external temperature ranged from −22 to 22 °C. Although it was not possible to adequately characterise thermal conditions within each load, the analysis indicated that the main risk factors for increased mortality were in spring and winter, an increased duration between loading and end of lairage, and a period of feed withdrawal before loading longer than 6 h. The risk of mortality increased with the weight of the birds and with an increase in rearing mortality. No relationships were found between the manner in which the broilers were handled and the percentages of DOAs or bruised birds.

Injury and mortality in broilers during handling and transport to slaughter

Multiple factors affect the risk of broiler injury and mortality during loading, transport, and lairage. These include the physical and pathophysiological condition of broilers before loading and the type of handling procedures used. The external environmental conditions have a major influence on the risk of mortality. Combinations of high stocking density, insufficient ventilation, and high temperature and humidity pose a risk of hyperthermia. Combinations of wet conditions, cold temperature, and air movement, increase the risk of hypothermia. However, protection from cold and wet conditions involves the use of side protection that restricts the trailer ventilation that can cause heat and moisture to build up in the load, increasing the risk of hyperthermia. Modular systems reduce the risk of injury and facilitate unloading into a lairage where temperature and ventilation can be controlled. The duration of loading, transport, and lairage increases the mortality risk. Deaths can occur during each stage and interactions between the duration of the preslaughter stages, the thermal environment, fasting, ill-health, and injury can reduce the physiological capacity of the birds to maintain homoeostasis resulting in exhaustion and death. Quality control and action on the identified risk factors should reduce injury and mortality during preslaughter handling and transport.

Factors affecting mortality risk during transportation of broiler chickens for slaughter in Atlantic Canada

Mortality of broilers during transport and lairage before slaughter represents an economic loss to the poultry industry and a welfare issue that needs to be addressed. In Canada, broilers can be transported long distances and be exposed to environmental factors, such as cold temperatures, that can affect the percentage of dead-on-arrivals or DOAs. Slaughter plant records for loads transported over a 19-month period in 2009-2010 were examined to identify factors affecting mortality risk (% DOA) during transportation from the rearing barn to the slaughter plant. Information from 2007 loads was analysed using a multilevel linear model. Most of the variation in the mortality risk occurred at the load level rather than at the producer or barn level. There were significant effects of bird sex, age and weight, catching team, journey duration and holding barn duration on mortality risk. The following environmental risk factors increased mortality risk: cold temperatures during the journey and in the holding barn, low crate stocking density during journeys at cold temperature and increased trailer temperature when in the holding barn. The analyses identified risk factors that can be used to refine management practices to mitigate some of the mortality risk. Increased mortality in some loads was associated with environmental conditions that caused deaths from hypothermia, whereas in other circumstances, some deaths likely occurred from hyperthermia. The climatic conditions in Atlantic Canada were responsible for significant risk factors that affected the mortality risk. Although refinement of the management practices described in this study, such as reduced journey and lairage durations, and increased crate stocking density can mitigate some of the mortality risk, the extreme cold conditions experienced during some parts of the year exceeded the capacity of the systems of transportation used to provide environmental conditions that minimise mortality.

Broiler chickens dead on arrival: associated risk factors and welfare indicators

The pre-slaughter phase of the production process has potentially important animal welfare implications, including mortality (recorded as "Dead on Arrivals"; DOA: ). To reduce DOA%, specific risk factors need to be identified. DOA% can also be used as a first and quick screening of pre-slaughter broiler welfare under commercial conditions. The aim of the present study was to identify risk factors for DOA% in commercial broiler flocks and to find associations between DOA% and animal-based indicators of broiler welfare during the pre-slaughter phase. Eighty-one transported flocks to five slaughter plants were assessed. Farmers provided information on the flock and observers gathered data on pre-slaughter factors. DOA% was recorded by slaughter plant personnel. The association between risk factors and DOA% was tested using linear mixed models, with slaughter plant as the random effect. Mean (± SE) DOA% was 0.30 ± 0.05% and median was 0.19% (range 0.04 to 3.34%). Two risk factors for DOA% were identified, both related to flock health status during the production phase. Higher DOA% was found when farmers did not check chick quality upon arrival (P = 0.011), although one extreme DOA% caused this significant effect. In addition, on-farm mortality during production (including selective culling) was negatively associated with DOA% (P = 0.011), potentially due to the selective culling on farm. Further research is needed on the impact of on-farm health status on welfare during the pre-slaughter phase, as the current study provided some evidence that on-farm factors are linked to mortality during the pre-slaughter phase. No specific characteristics of the pre-slaughter phase could be identified as risk factor for increased mortality. DOA% was positively associated with five welfare indicators, including indicators of thermal stress, which indicates the potential to use DOA% as a quick, cost-efficient screening tool for those welfare aspects.

Transport-induced mortality in Pekin ducks transported for slaughter in the Czech Republic

Data on the numbers of Pekin ducks transported to slaughterhouses between 2009 and 2014 and the numbers of ducks that died during these transports were recorded in cooperation with the State Veterinary Administration of the Czech Republic. In the monitored period, a total of 12,327,017 ducks were transported, of which 9,545 (0.077%) died. The levels of transport-related mortality over these years varied significantly (P < 0.001); the lowest mortality was observed in 2011 (0.059%) and the highest in 2013 (0.089%). The impact of distance on transport-related mortality in ducks was demonstrated. The lowest transport-related mortality (0.052%) was found for distances shorter than 50 km. It was significantly (P < 0.001) lower than the mortality rates connected with longer journeys. The greatest mortality rates were found for transport distances of 101–200 km (0.105%). In addition, the season of the year significantly affected transport-related mortality in Pekin ducks. The highest death losses were found in the summer (0.090%). Death losses of ducks connected with summer transports were significantly higher (P < 0.001) in comparison with transport-related mortality rates in any other season of the year. The lowest death losses were found in duck transports carried out in the autumn and winter (0.069% and 0.072%, respectively) with no significant difference between those two seasons. Shortening transport distances and maintaining a suitable micro-climate inside transport vehicles especially in the summer are thus two important factors that can contribute to reducing transport-related mortality in Pekin ducks in commercial practice.

A comparison of post-mortem findings in broilers dead-on-farm and broilers dead-on-arrival at the abattoir

Broiler mortality during transport to abattoirs (dead-on-arrival/DOA) evokes concern due to compromised animal welfare and associated economic losses. The general aim of this study was to characterize pathological lesions associated with mortality in broilers close to slaughter. The specific aim was to investigate whether disease at the end of the growth period may be a predisposing factor for DOA by describing and comparing the pathological findings in broilers dead-on-farm (DOF) in the final days of the production cycle and in broilers DOA from the same flocks. Gross post-mortem examinations were performed on 607 broilers from 32 flocks, either DOF (371) or DOA (236). In DOF broilers, the most common pathological lesions were lung congestion (37.7%), endocarditis (29.4%), and ascites (24.0%), whereas the most common findings in broilers DOA were lung congestion (57.2%) and trauma (24.6%). Lung congestion was more prevalent among DOA broilers compared to DOF broilers (P-value of > 0.001). A possible cause behind the pathological finding lung congestion is sudden death syndrome (SDS). The study indicates that steps in the transportation process per se cause the majority of pathological lesions such as lung congestion and trauma that may have led to the mortalities registered. Pre-existing diseases such as ascites and osteomyelitis may also predispose for DOA. Thus, factors relating to on-farm health, catching, and transportation are all areas of future investigation in order to reduce transport mortalities and to enhance welfare in broilers.

Pathological manifestations observed in dead-on-arrival broilers at a Danish abattoir

1. The mortality of broilers during pre-slaughter handling, including harvesting and transport, is an issue of increasing public concern which has led to the adoption of Council Directive EC/43/2007 implementing abattoir surveillance regarding the number of dead-on-arrival (DOA) broilers. 2. Pathological lesions and causes of death of DOA broilers at a Danish abattoir were investigated in a cross-sectional study comprising 300 DOA broilers (25 broilers from each of 12 randomly selected flocks). Major pathological manifestations of DOA broilers included severe pulmonary congestion (51.5%), lung congestion in combination with trauma (12.5%), trauma (10.2%), nephropathy accompanied by dehydration and/or discolouration (8.8%), morbus cordis (2.0%), septicaemia (1.7%) and suspected septicaemia (1.0%). Lung congestion accompanied by circulatory disturbances in other tissues was suggested to be due to suffocation. 3. Analyses of pathological diagnoses revealed that DOA broilers can be divided into two main categories, lung congestion and trauma, based on the chronicity of the lesions, both of which are primarily related to management and handling procedures. Most DOA broilers examined (74.2%) were estimated to have died as a consequence of events during pre-slaughter handling underlining the importance of increased focus on handling-related factors to reduce DOA rate.

Broiler ascites syndrome: collateral damage from efficient feed to meat conversion

Chickens have been raised as food for human consumption for over 4000 years. Over this time they have been continuously selected for specific desirable characteristics by active selection of parents to produce birds which fit perceived needs. Despite this long history of selective breeding and improvements in rearing techniques, the efficiency with which broiler meat is produced has shown a remarkable leap in recent decades. Persistent selection for rapid growth, high feed utilisation efficiency and large cut yield has resulted in modern meat-type poultry lines with superior genetic potential with regard to productivity. However, mortality and the incidence of metabolic diseases has increased in parallel with growth rate. One such disease is broiler ascites syndrome, which has been shown to be closely associated with the fast growth and high meat yield resulting from intense selection and with modern rearing techniques. The review is focused on the historical background, pathogenesis, epidemiology and prevention of broiler ascites syndrome in modern broiler production.

The effects of feed restriction and ambient temperature on growth and ascites mortality of broilers reared at high altitude

The development of ascites was investigated in broilers at low versus high altitudes, cold versus normal ambient temperatures (AT), and 3 feeding regimens. One-day-old chicks obtained at sea level were reared at high altitude (highA; 1,720 m; n = 576) with 2 AT treatments, low AT from 3 wk onward at highA (highA/cold) and normal AT from 3 wk onward at highA (highA/norm), or at sea level (normal AT from 3 wk onward at low altitude, lowA/norm; n = 540). Under highA/cold, AT ranged between 16 to 17 degrees C in the fourth week, 17 to 19 degrees C in the fifth week, and 19 to 21 degrees C thereafter. Under highA/norm and lowA/norm, AT was 24 degrees C in the fourth week and ranged between 22 to 24 degrees C thereafter. Broilers in each condition were divided into 3 groups: feed restriction (FR) from 7 to 14 d, FR from 7 to 21 d, and ad libitum (AL). Ascites mortality and related parameters were recorded. Low mortality (0.4%) occurred under lowA/norm conditions. Under highA/norm, mortality was lower in females (8.6%) than in males (13.8%) and was not affected by the feeding regimen. The highA/cold treatment resulted in higher mortality but only in males; it was 44.2% among highA/cold AL-fed males and only about 26% under the FR regimens, suggesting that FR helped some males to better acclimatize to the highA/cold environment and avoid ascites. However, mortality was only 13.3% in AL-fed males at highA/norm and FR did not further reduce the incidence of ascites under these conditions. Thus, avoiding low AT in the poultry house by slight heating was more effective than FR in reducing ascites mortality at highA. Compared with FR from 7 to 14 d, FR from 7 to 21 d did not further reduce mortality and reduced growth. At 47 d, the majority of surviving broilers at highA had high levels of hematocrit and right ventricle:total ventricle weight ratio (>0.29), but they were healthy and reached approximately the same BW as their counterparts at low altitude. This finding may suggest that in broilers reared at highA from day of hatch, the elevation in hematocrit and in right ventricle:total ventricle weight ratio happens gradually and therefore is not necessarily indicative of ascites development.

Maternal dietary n-3 fatty acids alter cardiac ventricle fatty acid composition, prostaglandin and thromboxane production in growing chicks

The effects of feeding n-6 and n-3 fatty acids to broiler hens on cardiac ventricle fatty acid composition, and prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) production of hatched chicks were investigated. Fertile eggs obtained from hens fed diets supplemented with 3.5% sunflower oil (Low n-3), 1.75% sunflower+1.75% fish oil (Medium n-3), or 3.5% fish oil (High n-3) were incubated. The hatched chicks were fed a diet containing 18:3 n-3, but devoid of longer chain n-6 and n-3 fatty acids for 42 days. Arachidonic acid content was lower in the cardiac ventricle of High n-3 and Medium n-3 compared to Low n-3 birds for up to 2 weeks (P<0.002). Long chain n-3 fatty acids were higher in the cardiac ventricle of chicks from hens fed High and Medium n-3 diets when compared to chicks from hens fed the Low n-3 diet. Differences in long chain n-3 fatty acids persisted up to four weeks of age (P<0.001). Peripheral blood mononuclear cells (PBMNC) of 7-day-old High n-3 broilers produced significantly lower PGE2 and TXA2 than PBMNC from Low n-3 and Medium n-3 birds. These results indicate that maternal dietary n-3 fatty acids increases cardiac ventricle n-3 fatty acids while reducing arachidonic acid and ex vivo PGE2 and TXA2 production during growth in broiler chickens.

Metabolic and cardiovascular diseases in poultry: role of dietary lipids

In the United States, supplemental dietary lipid is typically provided as an animal-vegetable blend using animal tallow or hydrogenated oils from the food industry. Lipids from these sources are rich in saturated, trans, n-6 fatty acids and poor in n-3 fatty acids. Linoleic (18:2 n-6) and alpha-linolenic (18:3 n-3) acids are essential fatty acids and are the precursors of long-chain n-6 and n-3 fatty acids such as arachidonic and eicosapentaenoic acids (EPA). Ester-linked arachidonic acid and EPA can be mobilized by phospholipase A(2) to generate free arachidonic acid and EPA, which can act as substrates for cyclooxygenase and lipooxygenase to produce eicosanoids. Eicosanoids derived from arachidonic acid, prostaglandin E2, thromboxane B2, and leukotriene B4 are proinflammatory and more potent than eicosanoids derived from EPA such as prostaglandin E3, thromboxane B3, and leukotriene B5. Developing dietary strategies in broiler chickens that enhance the n-3 fatty acid content of tissues is also associated with lipid oxidation and muscle product quality. Therefore, alternative strategies for enhancing tissue n-3 fatty acid content without affecting growth and product quality must be devised. The role of maternal (yolk) fatty acids in modulating the long-chain n-3 fatty acid content of tissues and eicosanoid production in chickens fed a diet lacking in long-chain n-3 fatty acids is investigated. Up to d 42 of growth, the cardiac tissues of chicks hatched from hens fed a high n-3 diet retained higher levels of long-chain n-3 fatty acids than those of chicks hatched from hens fed a low n-3 diet. Chicks hatched from hens fed a high n-3 diet produced less proinflammatory eicosanoids than chicks hatched from hens fed a low n-3 diet. Modulating maternal dietary n-3 fatty acids enhances tissue retention of n-3 fatty acids during growth and reduces proinflammatory eicosanoid production in chicks, which could lead to fewer metabolic and inflammatory-related disorders in poultry.