Turkey Production and Health: Current challenges
Published: July 18, 2014
By: Hafez Mohamed Hafez (Institute of Poultry Diseases, Faculty of Veterinary Medicine,Free University Berlin, Germany)
Summary
Several factors are influencing the turkey production and health such as strong global competition; changes in social, political and consumer perceptions with regard to food safety, animal welfare and environmental protection. The loss of consumer confidence and trust in the quality and safety of poultry meat and poultry products will remain a continuous major challenge. Many human foodborne infections are linked to poultry. Control and/or elimination of these organisms present a great challenge. The development of antibiotic resistant bacteria will also be a continuous public health hazard. The future concept of animal health will cover not only the absence of disease in birds, but also the relationship between the health of animals
and their welfare. It will also take into account social, economic and ethical considerations, as well as support the achievement of a high level of environmental protection. In general, consumer expectations for high quality products will strongly influence future production methods. This means that farmers, veterinarians, stockholders and all other partners involved in the production chain need to share more responsibilities. The present paper explores these points.
Keywords: Diseases, prevention, legislations, consumer expectations
Introduction
The modern turkey industry aims at high production and better quality at a low cost. This, in addition to an increase in the demand for poultry meat, necessitates constant, efficient and goal-oriented healthcare to prevent the development of diseases.
In the future several challenges and problems, in addition to the ones already existing, will face everybody involved in the turkey production chain. These will include: strong global competition; changes in social, political and consumer perceptions in regard to food safety and animal welfare; increase of environmental protection issues; a steady increase in the cost of feed; the emergence of new and unforeseen diseases, and new legislation that will serve to regulate the related issues. The present paper describes the main challenges facing the turkey production.
The modern turkey industry aims at high production and better quality at a low cost. This, in addition to an increase in the demand for poultry meat, necessitates constant, efficient and goal-oriented healthcare to prevent the development of diseases.
In the future several challenges and problems, in addition to the ones already existing, will face everybody involved in the turkey production chain. These will include: strong global competition; changes in social, political and consumer perceptions in regard to food safety and animal welfare; increase of environmental protection issues; a steady increase in the cost of feed; the emergence of new and unforeseen diseases, and new legislation that will serve to regulate the related issues. The present paper describes the main challenges facing the turkey production.
Strong global competition
Strong global competition and varying production costs in various regions will lead to an increase in the global movement of turkeys and poultry products. This, however, increases the risk of introducing diseases to areas that are now considered to be free from such diseases.
Strong global competition and varying production costs in various regions will lead to an increase in the global movement of turkeys and poultry products. This, however, increases the risk of introducing diseases to areas that are now considered to be free from such diseases.
Turkey diseases will remain a major challenge to the industry. Once an outbreak of a given disease occurs, it can explode into an epidemic and may have a significant negative effect on trade in a specific country, a continent or even globally.
The steady increase in the cost of feed will accelerate the global trade. In addition, the increase of biofuel and biogas production will reduce the available land for food grains and feed production, leading to a considerable increase of feed costs for animal production. In the future, the feed industry, however, will also be forced to take more responsibility not only for the quality of the feed ingredients, but also to ensure that no avian pathogens and unwanted contaminants or residues are present in the feed. In addition, climatic changes and limited water resources also need to be seriously considered, as they will have an influence on the cost of production (Hafez, 2009).
The steady increase in the cost of feed will accelerate the global trade. In addition, the increase of biofuel and biogas production will reduce the available land for food grains and feed production, leading to a considerable increase of feed costs for animal production. In the future, the feed industry, however, will also be forced to take more responsibility not only for the quality of the feed ingredients, but also to ensure that no avian pathogens and unwanted contaminants or residues are present in the feed. In addition, climatic changes and limited water resources also need to be seriously considered, as they will have an influence on the cost of production (Hafez, 2009).
Changes in social, political, and consumer perceptions - Food safety
The loss of the consumers trust and confidence in the quality and safety of poultry meat is a further challenge. Turkey meat can harbour different food borne pathogens. Many reports from recent years have shown that different Salmonella serovars and Campylobacter spp. are the most common causes of human food borne bacterial diseases linked to poultry.
In countries with intensive poultry production it has been determined that under current conditions it would be very difficult to eliminate Salmonella contamination in poultry production. However, the possibility to eliminate host specific serovars and to reduce non-host specific invasive serovars (paratyphoid) is realistic (Hafez, 1999, 2005).
In November 2003, the European Parliament Council Regulation 2160/2003/EC (EC, 2003a) on the control of salmonella and other specified food-borne zoonotic agents was passed. This regulation covers the adoption of targets for the reduction of the prevalence of specified zoonoses in animal populations at the level of primary production, including meat turkey. After the relevant control programme was approved, food business operators must have samples taken and analysed for e zoonoses and zoonotic agents. The flocks should be sampled also by the competent authority.
In June 2008 commission regulation (EC) No 584/2008 of implementing Regulation (EC) No 2160/2003 of the European Parliament and of the Council as regards a Community target for the reduction of the prevalence of S. Enteritidis and S. Typhimurium in turkeys was put into force (EC, 2008). The Community target is the reduction of both salmonella serovars to the maximum percentage of fattening and breeder flocks remaining positive to 1 % or less by 31 December 2012. The testing scheme necessary to verify progress in the achievement of the Community target is set out in the Annex of this regulation and should apply from 1st January 2010. All flocks of fattening and breeding turkeys should be investigated on the initiative of the food business operator within three weeks before the birds are moved to the slaughterhouse. In fattening turkeys at least two pairs of boot/sock swabs shall be taken. For free range flocks of turkeys, samples shall only be collected in the area inside the house. All boot/sock swabs must be pooled into one sample.
The loss of the consumers trust and confidence in the quality and safety of poultry meat is a further challenge. Turkey meat can harbour different food borne pathogens. Many reports from recent years have shown that different Salmonella serovars and Campylobacter spp. are the most common causes of human food borne bacterial diseases linked to poultry.
In countries with intensive poultry production it has been determined that under current conditions it would be very difficult to eliminate Salmonella contamination in poultry production. However, the possibility to eliminate host specific serovars and to reduce non-host specific invasive serovars (paratyphoid) is realistic (Hafez, 1999, 2005).
In November 2003, the European Parliament Council Regulation 2160/2003/EC (EC, 2003a) on the control of salmonella and other specified food-borne zoonotic agents was passed. This regulation covers the adoption of targets for the reduction of the prevalence of specified zoonoses in animal populations at the level of primary production, including meat turkey. After the relevant control programme was approved, food business operators must have samples taken and analysed for e zoonoses and zoonotic agents. The flocks should be sampled also by the competent authority.
In June 2008 commission regulation (EC) No 584/2008 of implementing Regulation (EC) No 2160/2003 of the European Parliament and of the Council as regards a Community target for the reduction of the prevalence of S. Enteritidis and S. Typhimurium in turkeys was put into force (EC, 2008). The Community target is the reduction of both salmonella serovars to the maximum percentage of fattening and breeder flocks remaining positive to 1 % or less by 31 December 2012. The testing scheme necessary to verify progress in the achievement of the Community target is set out in the Annex of this regulation and should apply from 1st January 2010. All flocks of fattening and breeding turkeys should be investigated on the initiative of the food business operator within three weeks before the birds are moved to the slaughterhouse. In fattening turkeys at least two pairs of boot/sock swabs shall be taken. For free range flocks of turkeys, samples shall only be collected in the area inside the house. All boot/sock swabs must be pooled into one sample.
In addition, flocks of breeding turkeys should be investigated during the rearing at day-old, at four weeks of age and two weeks before moving to the laying phase: During the laying period they are to be investigated at least every third week at the holding or at the hatchery.
Sampling by the competent authority in breeding turkey flocks with at least 250 birds should be carried as follows:
- once a year, all flocks on 10 % of holdings with at least 250 adult breeding turkeys between 30 and 45 weeks of age but including in any case all holdings where S. Enteritidis or S. Typhimurium was detected during the previous 12 months and all holdings with elite, great grandparents and grandparent breeding turkeys; this sampling may also take place at the hatchery,
- all flocks on holdings in case of detection of S. Enteritidis or S. Typhimurium from samples taken at the hatchery by food business operators or within the frame of official controls, to investigate the origin of infection.
- each time the competent authority considers it necessary.
Sampling by the competent authority in holdings with at least 500 fattening turkeys should be carried as mentioned by breeding flocks.
Campylobacter is the leading cause of zoonotic enteric infections worldwide (EFSA, 2011). Campylobacter infections in humans are mainly transmitted by contaminated food. No evidence has been found either for vertical transmission or for horizontal transmission from one flock to the next via persistent house-contamination. However, since the organism has been detected in the intestines of most slaughtered poultry, the major route for campylobacter contamination of poultry appears to be the horizontal transmission from the environment. Investigations indicated that the external campylobacter load per chicken is increasing during transport, de-feathering and evisceration, and decreasing at the other processing steps studied, with an overall reduction of the mean load from production-to-consumption of about 4 to 5 logs. Good hygienic practice protocols should be prepared and strictly followed in all stages of production. Biosecurity should be improved throughout the production chain. Since campylobacter is found in the environment, hygienic barriers should be constructed to keep them outside the house (Anderson et al., 2003).
Controlling these food borne organisms requires beside legislations a broader understanding of how microbial pathogens enter and move through the food chain, as well as the conditions that promote or inhibit growth for each type of organism.
Changes in social, political and consumer perceptions -- Antibiotic resistant and associated problems
The development of antibiotic resistance in bacteria, which is common in both, animals and humans, is and will also be a continue to be a continuous public health hazard.
Sampling by the competent authority in breeding turkey flocks with at least 250 birds should be carried as follows:
- once a year, all flocks on 10 % of holdings with at least 250 adult breeding turkeys between 30 and 45 weeks of age but including in any case all holdings where S. Enteritidis or S. Typhimurium was detected during the previous 12 months and all holdings with elite, great grandparents and grandparent breeding turkeys; this sampling may also take place at the hatchery,
- all flocks on holdings in case of detection of S. Enteritidis or S. Typhimurium from samples taken at the hatchery by food business operators or within the frame of official controls, to investigate the origin of infection.
- each time the competent authority considers it necessary.
Sampling by the competent authority in holdings with at least 500 fattening turkeys should be carried as mentioned by breeding flocks.
Campylobacter is the leading cause of zoonotic enteric infections worldwide (EFSA, 2011). Campylobacter infections in humans are mainly transmitted by contaminated food. No evidence has been found either for vertical transmission or for horizontal transmission from one flock to the next via persistent house-contamination. However, since the organism has been detected in the intestines of most slaughtered poultry, the major route for campylobacter contamination of poultry appears to be the horizontal transmission from the environment. Investigations indicated that the external campylobacter load per chicken is increasing during transport, de-feathering and evisceration, and decreasing at the other processing steps studied, with an overall reduction of the mean load from production-to-consumption of about 4 to 5 logs. Good hygienic practice protocols should be prepared and strictly followed in all stages of production. Biosecurity should be improved throughout the production chain. Since campylobacter is found in the environment, hygienic barriers should be constructed to keep them outside the house (Anderson et al., 2003).
Controlling these food borne organisms requires beside legislations a broader understanding of how microbial pathogens enter and move through the food chain, as well as the conditions that promote or inhibit growth for each type of organism.
Changes in social, political and consumer perceptions -- Antibiotic resistant and associated problems
The development of antibiotic resistance in bacteria, which is common in both, animals and humans, is and will also be a continue to be a continuous public health hazard.
It is generally known, that supplementation of poultry feed with antibiotic growth promoters (AGPs) improves performance of livestock. The effect of AGP on gut flora results in improvement of digestion, better absorption of nutrients, and a more stable balance in the microbial population. As consequence the prevalence and severity of intestinal disorders are reduced. However, AGPs also can increase the prevalence of drug-resistant bacteria. Based on „Precautionary Principle” and experiences made in some European countries, the EU completely banned the use growth-promoting antibiotics in feed of food producing animals by January 2006. Field observations in Europe showed that the poultry industry faced several problems after the ban of AGPs. The impact of the ban has been seen on the performances (body weight and feed conversion rate) as well as on the rearing husbandry (wet litter and ammonia level), animal welfare problem (foot pad dermatitis) and general health issues on the birds (enteric disorders due to dysbacteriosis and clostridial infections). Investigations indicate that competitive exclusion, prebiotics, probiotics, enzymes, and acids can impact the incidence and severity of clostridial infections in poultry. According to Langhout (2007) these approaches will need adaptations in the feeding program and/or feed production. The practical relevance of these approaches may vary between the different areas in the world. At this moment it is difficult to evaluate novel strategies developed to antibiotic-free feeding concepts. Combination of different approaches is necessary to enhance the performance and health status of the birds such as: selection of highly digestible feed ingredients to reduce nutrients for microbial degradation; introduction of a special pre-starter diet in the feeding program; improvement of climate control in the poultry house to avoid stress in the animal and keeping litter quality in optimal condition.
Multi-resistant bacteria are increasingly posing a hazard to human and animal health worldwide, impeding successful antibacterial treatment (Arias et al., 2010). In addition, the development of novel antibiotics does not keep step with the emergence of antimicrobial resistance in bacteria (García-Rey, 2010). Increasing application of antibiotics for the treatment of humans and animals and the use of the glycopeptide avoparcin in subtherapeutic levels as a growth promoter in the past have been generally held responsible for a progressive deterioration of the resistance situation in bacteria (Aarestrup, 2005; Alanis, 2005). Among multi-resistant bacteria, vancomycin-resistant enterococci (VRE) have been estimated as one
of the most common bacteria causing a rise in cases of nosocomial infections in humans in the last few years (Arias et al., 2010). The prevalence of vancomycin-resistant enterococci (VRE) in 20 turkey flocks reared in the southwest of Germany was recently investigated (Sting et al., 2013). The VRE could be isolated by means of a procedure combining bacterial cultivation in an enrichment broth and on a selective solid media. Enterococci were identified biochemically and subsequently tested on the presence of the vancomycin resistance genes vanA, vanB (B1/B2/B3), and vanC (C1/C2/C3) using real-time PCR assays. Vancomycin-resistant enterococci were detected in 15 (75%) of the 20 turkey flocks investigated. In 5 flocks, all
animal samples and environmental dust samples taken were VRE-negative. In a total of cultivated 68 isolates from birds and dust samples, enterococci bearing van-genes were detected. Of these, 12 isolates carried the vanA gene (17.6%) and 56 isolates carried the vanC1 gene (82.6%). Neither vanB (B1, B2, B3) genes nor the vanC2 or vanC3 genes could be detected.
In addition, Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have been isolated from a number of livestock species and persons involved in animal production. Infections with MRSA often prove difficult and expensive to treat. During the last few years LA-MRSA have been isolated from a number of farm animal species including pigs, veal calves, dairy cattle and broilers (de Neeling, et al. 2007; Hasman et al., 2010, Persoons et al., 2009). Also turkey meat was shown to be contaminated with MRSA (de Boer et al., 2009), however, only limited information is available concerning the situation in turkey flocks with respect to prevalence, site of colonization or infection and involved strains. Recently, Richter et al. (2012) investigated the prevalence of LA-MRSA in fattening turkeys and people living on farms that house fattening turkeys. Eighteen (90%) of 20 investigated flocks were positive for MRSA. All female flocks were positive, while 8 male flocks were positive. On 12 of the farms 22 (37.3%) of 59 persons sampled were positive for MRSA. None of them showed clinical symptoms indicative of an MRSA infection. People with frequent access to the stables were more likely to be positive for MRSA. In most flocks MRSA that could be assigned to clonal complex (CC) 398 were detected. In five flocks MRSA of spa-type t002 that is not related to CC398 were identified. Moreover, other methicillin-resistant Staphylococcus spp. were detected on 11 farms and in eight people working on the farms.
Multi-resistant bacteria are increasingly posing a hazard to human and animal health worldwide, impeding successful antibacterial treatment (Arias et al., 2010). In addition, the development of novel antibiotics does not keep step with the emergence of antimicrobial resistance in bacteria (García-Rey, 2010). Increasing application of antibiotics for the treatment of humans and animals and the use of the glycopeptide avoparcin in subtherapeutic levels as a growth promoter in the past have been generally held responsible for a progressive deterioration of the resistance situation in bacteria (Aarestrup, 2005; Alanis, 2005). Among multi-resistant bacteria, vancomycin-resistant enterococci (VRE) have been estimated as one
of the most common bacteria causing a rise in cases of nosocomial infections in humans in the last few years (Arias et al., 2010). The prevalence of vancomycin-resistant enterococci (VRE) in 20 turkey flocks reared in the southwest of Germany was recently investigated (Sting et al., 2013). The VRE could be isolated by means of a procedure combining bacterial cultivation in an enrichment broth and on a selective solid media. Enterococci were identified biochemically and subsequently tested on the presence of the vancomycin resistance genes vanA, vanB (B1/B2/B3), and vanC (C1/C2/C3) using real-time PCR assays. Vancomycin-resistant enterococci were detected in 15 (75%) of the 20 turkey flocks investigated. In 5 flocks, all
animal samples and environmental dust samples taken were VRE-negative. In a total of cultivated 68 isolates from birds and dust samples, enterococci bearing van-genes were detected. Of these, 12 isolates carried the vanA gene (17.6%) and 56 isolates carried the vanC1 gene (82.6%). Neither vanB (B1, B2, B3) genes nor the vanC2 or vanC3 genes could be detected.
In addition, Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have been isolated from a number of livestock species and persons involved in animal production. Infections with MRSA often prove difficult and expensive to treat. During the last few years LA-MRSA have been isolated from a number of farm animal species including pigs, veal calves, dairy cattle and broilers (de Neeling, et al. 2007; Hasman et al., 2010, Persoons et al., 2009). Also turkey meat was shown to be contaminated with MRSA (de Boer et al., 2009), however, only limited information is available concerning the situation in turkey flocks with respect to prevalence, site of colonization or infection and involved strains. Recently, Richter et al. (2012) investigated the prevalence of LA-MRSA in fattening turkeys and people living on farms that house fattening turkeys. Eighteen (90%) of 20 investigated flocks were positive for MRSA. All female flocks were positive, while 8 male flocks were positive. On 12 of the farms 22 (37.3%) of 59 persons sampled were positive for MRSA. None of them showed clinical symptoms indicative of an MRSA infection. People with frequent access to the stables were more likely to be positive for MRSA. In most flocks MRSA that could be assigned to clonal complex (CC) 398 were detected. In five flocks MRSA of spa-type t002 that is not related to CC398 were identified. Moreover, other methicillin-resistant Staphylococcus spp. were detected on 11 farms and in eight people working on the farms.
In Europe the Commission regulations 2205/2001 and 1798/1995 have stopped the usage of dimitridazoles as therapeutic or prophylactic drugs in food producing animals (EC, 1995, 2001) and council regulation1756/2002 banned the application of Nifursol from 31 March 2003 (EC, 2002). Following a ban of all previously used products for prophylaxis or treatment in the EU, of histomonosis is becoming increasingly responsible for considerable economic problems for the turkey industry, causing disastrous economic losses. A large number of outbreaks in turkey and layer flocks with varying mortality were reported in several European countries.
Changes in social, political and consumer perceptions – Animal welfare
Currently, there is great concern that serious animal welfare and health problems might have been caused already due to genetic selection practices within the turkey industry. Fact is that genetic selection practices within the turkey industry have achieved significant progress in terms of growth rate, better feed conversion, better meat yield and low production cost. All the time this was accompanied by continuous improvement in husbandry practices, nutrition, and disease control. The most outstanding and visible changes in modern turkey compared to their ancestors is the rapid growth and the higher percentage of breast muscle. As a consequence it is important to understand the relationship between genetic selection pressures and other factors that may have a subsequent impact on the health conditions. This includes the effects on the growth and development of supporting structures such as bone and blood supply. Compared to traditional lines the highly selected birds have reduced cardiopulmonary capacity in relation to their muscle mass, as the ratio of heart and lung development has strongly decreased in modern turkeys. In addition, it is known that the blood pressure of the traditional turkey is only about half the value of that of the modern one (Norci and Montella, 2003; Havenstein et al., 2004). This physiological imbalance causes problems such as sudden death syndrome, aortic rupture, deep pectoral myopathy and skeletal disorders, which currently receive a lot of attention as a cause of concern from the animal welfare point of view and are mostly accompanied by economic losses for turkey meat producers due to mortality, predisposition to cannibalism, retardation of growth, increase of the condemnation rate and downgrading at the processing plant. The most common problems of the musculoskeletal system related to fast growth comprise dyschondroplasia and footpad dermatitis. The incidence and severity of both can be influenced by nutrition and genetic selection (Farquharson, and Jefferies, 2000; Mayne, 2003).
According to a published report on a new Animal Health Strategy for the European Union (2007 - 2013), the concept of animal health not only covers the absence of disease in animals, but also the relationship between the health of animals and their welfare. It will also take into account social, economic and ethical considerations, as well as support the achievement of a high level of environmental protection (EC, 2007).
Currently, there is great concern that serious animal welfare and health problems might have been caused already due to genetic selection practices within the turkey industry. Fact is that genetic selection practices within the turkey industry have achieved significant progress in terms of growth rate, better feed conversion, better meat yield and low production cost. All the time this was accompanied by continuous improvement in husbandry practices, nutrition, and disease control. The most outstanding and visible changes in modern turkey compared to their ancestors is the rapid growth and the higher percentage of breast muscle. As a consequence it is important to understand the relationship between genetic selection pressures and other factors that may have a subsequent impact on the health conditions. This includes the effects on the growth and development of supporting structures such as bone and blood supply. Compared to traditional lines the highly selected birds have reduced cardiopulmonary capacity in relation to their muscle mass, as the ratio of heart and lung development has strongly decreased in modern turkeys. In addition, it is known that the blood pressure of the traditional turkey is only about half the value of that of the modern one (Norci and Montella, 2003; Havenstein et al., 2004). This physiological imbalance causes problems such as sudden death syndrome, aortic rupture, deep pectoral myopathy and skeletal disorders, which currently receive a lot of attention as a cause of concern from the animal welfare point of view and are mostly accompanied by economic losses for turkey meat producers due to mortality, predisposition to cannibalism, retardation of growth, increase of the condemnation rate and downgrading at the processing plant. The most common problems of the musculoskeletal system related to fast growth comprise dyschondroplasia and footpad dermatitis. The incidence and severity of both can be influenced by nutrition and genetic selection (Farquharson, and Jefferies, 2000; Mayne, 2003).
According to a published report on a new Animal Health Strategy for the European Union (2007 - 2013), the concept of animal health not only covers the absence of disease in animals, but also the relationship between the health of animals and their welfare. It will also take into account social, economic and ethical considerations, as well as support the achievement of a high level of environmental protection (EC, 2007).
Emergence and Re-emergence of turkey diseases
Beside several management related and political issues, emerging and re-emerging diseases and/or infections of turkeys are and will remain a continuous challenge for poultry veterinarians and the turkey industry.
An emergency animal disease (EAD) can be defined as a disease condition that is likely to have a significant effect on livestock - potentially resulting in livestock deaths, production losses and in some cases impacts on human health and the environment (Geering et al., 1999). Morse (1995) defined human emerging diseases as infections that either have newly appeared in a population or have already existed, but are rapidly increasing in incidence or geographic range. In general, most of emerging infections appear to be caused by pathogens already present in the environment that acquired a selective advantage or afforded an opportunity to infect new host populations (Morse, 1995). Moreover, there are other animal health emergencies that may be caused by non- infectious agents such as chemical residue problems in livestock or food safety problems through contamination of animal products. Several factors can precipitate and/or predispose to disease emergence. These include changes in the structure and development of the poultry industry, strong global competition and varying production costs in different continents and countries, leading to an increase of the global movement of poultry and poultry products. This could also increase the risk to introduce infections to areas which were previously considered to be free from such diseases (Hafez, 2009). Re-emerging and resurging infections are those that existed in the past but are now rapidly increasing either in incidence or in geographical or host range.
Beside several management related and political issues, emerging and re-emerging diseases and/or infections of turkeys are and will remain a continuous challenge for poultry veterinarians and the turkey industry.
An emergency animal disease (EAD) can be defined as a disease condition that is likely to have a significant effect on livestock - potentially resulting in livestock deaths, production losses and in some cases impacts on human health and the environment (Geering et al., 1999). Morse (1995) defined human emerging diseases as infections that either have newly appeared in a population or have already existed, but are rapidly increasing in incidence or geographic range. In general, most of emerging infections appear to be caused by pathogens already present in the environment that acquired a selective advantage or afforded an opportunity to infect new host populations (Morse, 1995). Moreover, there are other animal health emergencies that may be caused by non- infectious agents such as chemical residue problems in livestock or food safety problems through contamination of animal products. Several factors can precipitate and/or predispose to disease emergence. These include changes in the structure and development of the poultry industry, strong global competition and varying production costs in different continents and countries, leading to an increase of the global movement of poultry and poultry products. This could also increase the risk to introduce infections to areas which were previously considered to be free from such diseases (Hafez, 2009). Re-emerging and resurging infections are those that existed in the past but are now rapidly increasing either in incidence or in geographical or host range.
Health disorders and infectious diseases of turkeys are mostly associated with severe economic losses. Several pathogens are incriminated as possible causes of many disease complexes of turkey poults either alone (mono-causal) or in synergy with different other micro-organisms (multi-causal) or accompanied by non-infectious factors. “Non-infectious” means all factors which influence the bird health and include house structure, climatic conditions (ventilation, temperature, and litter condition), stocking density, feed and water supply, hygienic condition as well as the knowledge and qualification of the stockman. These factors affect each other and can promote or inhibit the health condition of the flock. In aim to achieve desired performance results, managers of turkey flocks should integrate good environment, husbandry, nutrition and disease control programs. The rearing management must be directed to satisfy the bird’s requirements, to promote the production and to prevent diseases condition. Any disturbance will cause stress, which will reduce the resistance of the birds, increase their susceptibility to infections and reduce their immune-response to vaccines. Infectious diseases caused by several infectious agents such as viruses, bacteria, fungus and parasites are involved in many disease conditions. These infectious agents can be introduced and spread in turkey farms by different routes. It occurs by vertical and/or horizontal route. At early days of age the main disease problems are related to vertically transmitted infections and improper hatchery eggs sanitation (Yolk sac infection/ Omphalitis) with salmonella, E. coli, mycoplasma, Aspergillus, staphylococci, streptococci, pseudomonas and avian encephalomyelitis. Those and other infectious agents can also be transmitted horizontally (laterally) by direct contact between infected and non-infected birds. Currently, the most important problems of turkeys are respiratory diseases, possibly caused by avian metapneumovirus and /or Ornithobacterium rhinotracheale and E. coli. Furthermore, enteric disorders caused by several viral agents such as coronavirus, astrovirus, rotavirus or due to parasitic infestation such as coccidia and histomonas are common problems.
The severity of clinical signs, duration of the disease and mortality are extremely variable and are influenced by kind, virulence and pathogenicity of the infectious agent as well as by many environmental factors such as poor management, inadequate ventilation, high stocking density, poor litter conditions, poor hygiene, high ammonia level, concurrent diseases and the type of secondary infection.
Future expectations Disease diagnosis, treatment and control
In future improvements in laboratory diagnosis, such as diagnostic micro array and other technologies, will allow faster, more sensitive and more accurate diagnosis of infectious diseases, and early interventions will become a reality.
However, only a few authorised pharmaceutical veterinary products will be available for the treatment of poultry as food producing animals. Future scientific findings on the pathogenic mechanisms of bacteria will help to improve the treatment of bacterial infections, and instead of non-specific antibiotic therapy, new drugs will be able to target the signalling mechanisms, which are able to disrupt the pathogenic effects of the pathogen bacteria. Vaccination is regarded as one of the most beneficial biopharmaceutical interventions due to its ability to induce protection against infectious diseases through targeted activation of the immune system. Many valuable new vaccine production technologies have been developed as a result of rapid progress in various areas. The use of future progressive vaccine production technologies, such as recombinant, subunit, reverse genetic and nucleic acid vaccines, can significantly reduce the cost of vaccines, ensure better efficacy, and allow easy and rapid intervention to face the steady mutation of the microorganisms. Furthermore, the development of efficient vaccines against bacterial infections will lead to a reduction of the use of antibiotics and subsequently of the development of resistant bacteria. Genetic resistance and selective breeding: to improve production traits and health is a long-standing goal of the industry. The desire to enhance breeding strategies through the use of molecular techniques (genetic linkage maps) will lead to the characterisation of genome structure and genes that are associated with production traits and disease susceptibility and resistance. This will allow selecting bird lines that are genetically resistant to several pathogens. In addition, improvement of rearing technology, management and nutrition will help to maintain bird comfort (Hafez 2009).
In future improvements in laboratory diagnosis, such as diagnostic micro array and other technologies, will allow faster, more sensitive and more accurate diagnosis of infectious diseases, and early interventions will become a reality.
However, only a few authorised pharmaceutical veterinary products will be available for the treatment of poultry as food producing animals. Future scientific findings on the pathogenic mechanisms of bacteria will help to improve the treatment of bacterial infections, and instead of non-specific antibiotic therapy, new drugs will be able to target the signalling mechanisms, which are able to disrupt the pathogenic effects of the pathogen bacteria. Vaccination is regarded as one of the most beneficial biopharmaceutical interventions due to its ability to induce protection against infectious diseases through targeted activation of the immune system. Many valuable new vaccine production technologies have been developed as a result of rapid progress in various areas. The use of future progressive vaccine production technologies, such as recombinant, subunit, reverse genetic and nucleic acid vaccines, can significantly reduce the cost of vaccines, ensure better efficacy, and allow easy and rapid intervention to face the steady mutation of the microorganisms. Furthermore, the development of efficient vaccines against bacterial infections will lead to a reduction of the use of antibiotics and subsequently of the development of resistant bacteria. Genetic resistance and selective breeding: to improve production traits and health is a long-standing goal of the industry. The desire to enhance breeding strategies through the use of molecular techniques (genetic linkage maps) will lead to the characterisation of genome structure and genes that are associated with production traits and disease susceptibility and resistance. This will allow selecting bird lines that are genetically resistant to several pathogens. In addition, improvement of rearing technology, management and nutrition will help to maintain bird comfort (Hafez 2009).
Conclusions
In the future, the global cooperation and trade will force the governments to harmonize the existing different legislations related to trade, animal disease control, animal nutrition as well as the licensing of drugs and vaccines for veterinary use. Last but not least the consumer expectations for high standards quality of poultry products will strongly influence the production methods. This means that farmers, veterinarians, stockholders and all other partners involved in the production chain will have to share more responsibilities and that cooperation will be intensified.
In the future, the global cooperation and trade will force the governments to harmonize the existing different legislations related to trade, animal disease control, animal nutrition as well as the licensing of drugs and vaccines for veterinary use. Last but not least the consumer expectations for high standards quality of poultry products will strongly influence the production methods. This means that farmers, veterinarians, stockholders and all other partners involved in the production chain will have to share more responsibilities and that cooperation will be intensified.
References
AARESTRUP, F.M. (2005) Veterinary drug usage and antimicrobial resistance in bacteria of animal origin. Basic Clinical Pharmacology and Toxicology 96:271–281.
ALANIS, A.J. (2005) Resistance to antibiotics: Are we in the postantibiotic era? Archives of Medical Research 36:697-705.
ARIAS, C.A., CONTRERAS, G.A. and MURRAY, B.E. (2010) Management of multidrugresistant enterococcal infections. Clinical Microbiology and Infection 16:555–562.
ANDERSON, S., CHRISTENSEN, B. B., FAZIL, A., HARTNETT, E., LAMMERDING, A., NAUTA, M., PAOLI, G. and ROSENQUIST, H. (2003) A draft risk assessment of Campylobacter spp. in broiler chickens. Joint FAO/WHO Activities on Risk Assessment of Microbiological Hazards in Foods.
DE BOER, E., Zwartkruis-Nahuis, J.T.M., Wit, B., Huijsdens, X.W., de Neeling, A.J., Bosch, T., van Oosterom, R.A.A., Vila, A. and Heuvelink, A.E. (2009) Prevalence of methicillin-resistant Staphylococcus aureus in meat. International Journal of Food Microbiology 134: 52–56.
DE NEELING A.J., VAN DEN BROEH, M., SPALBURG, E.C., VAN SANTENVERHEUVEL M.G., DAM-DEISZ, W., BOSHUIZEN, H.C., DE GIESSEN, A., VAN DUIJKEREN, E. and HUIJSDENS, X.W. (2007) High prevalence of methicillin resistant Staphylococcus aureus in pigs. Veterinary Microbiology 122: 366-372.
EC (1995) Commission Regulation (EC) No 1798/95 of July 25, 1995 amending Annex IV to Council Regulation (EEC) No 2377/90 laying down a Community procedure for the establishment of maximum residue limits of veterinary medicinal products in foodstuffs of animal origin. Official Journal of the European Commission L174: 20-21.
EC (2001) Commission Regulation (EC) No 2205/2001 of November 14, 2001 amending Council Directive 70/524/EEC concerning additives in feeding stuffs as regards withdrawal of the authorization of certain additives. Official Journal of the European Commission L297: 3-4.
EC (2002) Council Regulation (EC) No 1756/2002 of September 23, 2002 amending Directive 70/524/EEC concerning additives in feeding stuffs as regards withdrawal of the authorisation of an additive and amending Commission Regulation (EC) No 2430/1999. Official Journal of the European Commission; L265:1–2.
EC (2007) A new Animal Health Strategy for the European Union (2007-2013) where “Prevention is better than cure”. http://ec.europa.eu/food/animal/diseases/strategy/index
EC (2008) Regulation (EC) No 584/2008 of 20 June 2008 implementing Regulation (EC) No 2160/2003 of the European Parliament and of the Council as regards a Community target for the reduction of the prevalence of Salmonella enteritidis and Salmonella typhimurium in turkeys. Official Journal of the European Commission L 162, 3-8.
EFSA (2011) The European Union Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and Food-borne Outbreaks in 2009. The EFSA Journal 9(3): http://www.efsa.europa.eu/en/efsajournal/pub/2090.htm
FARQUHARSON, C. and JEFFERIES, D. (2000) Chondrocytes and longitudinal bone growth: the development of tibial dyschondroplasia. Poultry Science 79: 994-1004.
GARCÍA-REY, C. (2010) The role of the pharmaceutical industry. Why are new antibiotics not being marketed?. Enfermedades Infecciosas y Microbiología Clínica 28- Suppl4:45–49.
GEERING, W.A., ROEDER, P.L. and OBI, T.U. (1999) Manual on the preparation of national animal disease emergency preparedness plans. Food and Agriculture Organization of the United Nations (FAO). Rome. M-27-ISBN 92-5-104290-X.
HAFEZ, H.M. (1999) Poultry meat and food safety: pre- and post-harvest approaches to reduce food borne pathogens. World’s Poultry Science Journal 55: 269-280.
HAFEZ, H.M. (2005) Governmental regulations and concept behind eradication and control of some important poultry diseases. World’s Poultry Science Journal 61: 569-582.
Hafez, H.M. (2009) Poultry health- looking ahead to 2034. World Poultry, 25: 16-17.
Hasman, H., Moodley, A., Guardabassi, L., Stegger, M., Skov, R.L., Aarestrup F.M. (2010) spa Typing distribution in Staphylococcus aureus originating from pigs, cattle and poultry. Veterinary Microbiology 141: 326-331.
HAVENSTEIN, G.B., FERKET, P.R., GRIMES, J.R., QURESHI, M.A. and NESTOR, K.E.(2004) Changes in the Performance of Turkeys 1966 - 2003. Proceedings of the 27th Technical Turkey Conference, 2004; pp. 11-18.
LANGHOUT, P. (2007) Broilers nutrition optimisation. Animal Feed Manufactures Association Matrix 16(2): 33-37.
MAYNE, R.K. (2003) A review of the aetiology and possible causative factors of foot pad dermatitis in growing turkeys and broilers. World’s Poultry Science Journal 61: 256-267.
MORSE, S.S. (1995) Factors in the Emergence of Infectious Diseases. Emerging Infectious Diseases 1: 1-15.
NORCI, C. and MONTELLA, A.L. (2003) Turkey welfare: Is it only a management problem? In: Turkey Production: Balance act between consumer protection, animal welfare and economic aspects. (Ed. H. M. HAFEZ), Publisher Ulmer Verlag, Stuttgart, Germany- ISBN 3-8001-4630-4. 2003; pp.143-148.
PERSOONS, D., VAN HOOREBEKE, S., HERMANS, K., BUTAYE, P., DE KRUIF, A., HAESEBROUCK, F. and DEWULF, J. (2009): Methicillin-Resistant Staphylococcus aureus in Poultry. Emerging Infectious Diseases 15: 853-856.
RICHTER, A., STING, R., POPP, C., RAU, J., TENHAGEN, B.A., GUERRA, B., HAFEZ H.M. and FETSCH A. (2012) Prevalence of types of methicillin-resistant Staphylococcus aureus in turkey flocks and personnel attending the animals. Epidemiology and Infection 140: 2223- 2232.
STING, R., RICHTER, A., POPP, C. and HAFEZ, H.M. (2013).Occurrence of vancomycin-resistant enterococci in turkey flocks. Poultry Science 92:346–351.
AARESTRUP, F.M. (2005) Veterinary drug usage and antimicrobial resistance in bacteria of animal origin. Basic Clinical Pharmacology and Toxicology 96:271–281.
ALANIS, A.J. (2005) Resistance to antibiotics: Are we in the postantibiotic era? Archives of Medical Research 36:697-705.
ARIAS, C.A., CONTRERAS, G.A. and MURRAY, B.E. (2010) Management of multidrugresistant enterococcal infections. Clinical Microbiology and Infection 16:555–562.
ANDERSON, S., CHRISTENSEN, B. B., FAZIL, A., HARTNETT, E., LAMMERDING, A., NAUTA, M., PAOLI, G. and ROSENQUIST, H. (2003) A draft risk assessment of Campylobacter spp. in broiler chickens. Joint FAO/WHO Activities on Risk Assessment of Microbiological Hazards in Foods.
DE BOER, E., Zwartkruis-Nahuis, J.T.M., Wit, B., Huijsdens, X.W., de Neeling, A.J., Bosch, T., van Oosterom, R.A.A., Vila, A. and Heuvelink, A.E. (2009) Prevalence of methicillin-resistant Staphylococcus aureus in meat. International Journal of Food Microbiology 134: 52–56.
DE NEELING A.J., VAN DEN BROEH, M., SPALBURG, E.C., VAN SANTENVERHEUVEL M.G., DAM-DEISZ, W., BOSHUIZEN, H.C., DE GIESSEN, A., VAN DUIJKEREN, E. and HUIJSDENS, X.W. (2007) High prevalence of methicillin resistant Staphylococcus aureus in pigs. Veterinary Microbiology 122: 366-372.
EC (1995) Commission Regulation (EC) No 1798/95 of July 25, 1995 amending Annex IV to Council Regulation (EEC) No 2377/90 laying down a Community procedure for the establishment of maximum residue limits of veterinary medicinal products in foodstuffs of animal origin. Official Journal of the European Commission L174: 20-21.
EC (2001) Commission Regulation (EC) No 2205/2001 of November 14, 2001 amending Council Directive 70/524/EEC concerning additives in feeding stuffs as regards withdrawal of the authorization of certain additives. Official Journal of the European Commission L297: 3-4.
EC (2002) Council Regulation (EC) No 1756/2002 of September 23, 2002 amending Directive 70/524/EEC concerning additives in feeding stuffs as regards withdrawal of the authorisation of an additive and amending Commission Regulation (EC) No 2430/1999. Official Journal of the European Commission; L265:1–2.
EC (2007) A new Animal Health Strategy for the European Union (2007-2013) where “Prevention is better than cure”. http://ec.europa.eu/food/animal/diseases/strategy/index
EC (2008) Regulation (EC) No 584/2008 of 20 June 2008 implementing Regulation (EC) No 2160/2003 of the European Parliament and of the Council as regards a Community target for the reduction of the prevalence of Salmonella enteritidis and Salmonella typhimurium in turkeys. Official Journal of the European Commission L 162, 3-8.
EFSA (2011) The European Union Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and Food-borne Outbreaks in 2009. The EFSA Journal 9(3): http://www.efsa.europa.eu/en/efsajournal/pub/2090.htm
FARQUHARSON, C. and JEFFERIES, D. (2000) Chondrocytes and longitudinal bone growth: the development of tibial dyschondroplasia. Poultry Science 79: 994-1004.
GARCÍA-REY, C. (2010) The role of the pharmaceutical industry. Why are new antibiotics not being marketed?. Enfermedades Infecciosas y Microbiología Clínica 28- Suppl4:45–49.
GEERING, W.A., ROEDER, P.L. and OBI, T.U. (1999) Manual on the preparation of national animal disease emergency preparedness plans. Food and Agriculture Organization of the United Nations (FAO). Rome. M-27-ISBN 92-5-104290-X.
HAFEZ, H.M. (1999) Poultry meat and food safety: pre- and post-harvest approaches to reduce food borne pathogens. World’s Poultry Science Journal 55: 269-280.
HAFEZ, H.M. (2005) Governmental regulations and concept behind eradication and control of some important poultry diseases. World’s Poultry Science Journal 61: 569-582.
Hafez, H.M. (2009) Poultry health- looking ahead to 2034. World Poultry, 25: 16-17.
Hasman, H., Moodley, A., Guardabassi, L., Stegger, M., Skov, R.L., Aarestrup F.M. (2010) spa Typing distribution in Staphylococcus aureus originating from pigs, cattle and poultry. Veterinary Microbiology 141: 326-331.
HAVENSTEIN, G.B., FERKET, P.R., GRIMES, J.R., QURESHI, M.A. and NESTOR, K.E.(2004) Changes in the Performance of Turkeys 1966 - 2003. Proceedings of the 27th Technical Turkey Conference, 2004; pp. 11-18.
LANGHOUT, P. (2007) Broilers nutrition optimisation. Animal Feed Manufactures Association Matrix 16(2): 33-37.
MAYNE, R.K. (2003) A review of the aetiology and possible causative factors of foot pad dermatitis in growing turkeys and broilers. World’s Poultry Science Journal 61: 256-267.
MORSE, S.S. (1995) Factors in the Emergence of Infectious Diseases. Emerging Infectious Diseases 1: 1-15.
NORCI, C. and MONTELLA, A.L. (2003) Turkey welfare: Is it only a management problem? In: Turkey Production: Balance act between consumer protection, animal welfare and economic aspects. (Ed. H. M. HAFEZ), Publisher Ulmer Verlag, Stuttgart, Germany- ISBN 3-8001-4630-4. 2003; pp.143-148.
PERSOONS, D., VAN HOOREBEKE, S., HERMANS, K., BUTAYE, P., DE KRUIF, A., HAESEBROUCK, F. and DEWULF, J. (2009): Methicillin-Resistant Staphylococcus aureus in Poultry. Emerging Infectious Diseases 15: 853-856.
RICHTER, A., STING, R., POPP, C., RAU, J., TENHAGEN, B.A., GUERRA, B., HAFEZ H.M. and FETSCH A. (2012) Prevalence of types of methicillin-resistant Staphylococcus aureus in turkey flocks and personnel attending the animals. Epidemiology and Infection 140: 2223- 2232.
STING, R., RICHTER, A., POPP, C. and HAFEZ, H.M. (2013).Occurrence of vancomycin-resistant enterococci in turkey flocks. Poultry Science 92:346–351.
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