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The commercial application of enzymes as a feed additive has a history of less than 20 years. During this period, the feed enzyme industry came into existence and it has gone through several phases of development. The first phase was the use of enzymes to enhance nutrient digestibility, focusing primarily on removing the anti-nutritive effects of non-starch polysaccharides (NSP), such as arabinoxylans and β-glucans, from broiler diets based on viscous grains like wheat, rye, barley or triticale. During the early 1990s, the scope of enzyme application expanded to consider nutrients other than NSP and benefits other than digestibility enhancement. Phytase is a prime example, where not only was it used to increase the utilisation of phtate P, but also to alleviate environmental burdens by reducing P excretion in the excreta. The industry then started to advocate enzyme addition to poultry diets based on non-viscous grains, such as sorghum and corn. Although such a use is not uncommon in some parts of the world, the industry is still in search for highly efficacious enzymes for non-viscous cereal grains. The next phase is the application of enzymes to non-cereal grain components of the diet. These vegetable protein sources are often high in NSP, which are poorly characterised in regard to their molecular structures. Significant progress has been made on characterisation of the NSP in soyabean, but the industry has not been able to produce commercially viable products that consistently improve the digestibility of vegetable protiens. The enzyme industry today is constantly searching for new areas of application. Some recent data demonstrate the role of glycanases (charbohydrate degrading enzymes) as an alternative to in-feed antibiotics. It is possible to produce enzymes tailored for (a) the generation of specific low molecular weight carbohydrates in vivo, which, in turn, produce specific health outcomes in birds; (b) de-activation of anti-nutrients other than NSP and phtate, and (c) degrading of non-conventional feed resources to yield ME. The development of enzyme technology needs to go hand in hand with better characterisation of substrate structures, the gut microflora, and the immune system.
Malabsorption syndrome (MAS) is a multifactorial disease that causes intestinal disorders in broilers due to infection of the gastrointestinal tract with different infectious agents. The exact aetiology is unknown, although several viruses are isolated from MAS affected chickens. None of these isolated infectious agents alone inducted the malabsorption syndrome. MAS in broilers is characterised by poor growth and lesions in the GI-tract, mainly in the small intestine. Experimentally, MAS can be induced in one-day old broilers by oral inoculation of homogenates obtained from digestive tract tissues of MAS affected broilers. Susceptibility to the MAS syndrome differs between broiler lines. The susceptibility to MAS is correlated with the severity of the lesions, apoptosis and heterophil infiltration of the jejunum. Susceptibility to MAS is also related to the frequency of CD4 and CD8 positive T-cells in the intestinal villus and the mRNA expression level of different cytokines in control and in MAS induced broilers. With the use of micro-arrays differences in gene expression levels between broiler lines that differ in MAS susceptibility were observed. From these experiments genes that are immune and food absorption related were identified. If some of these genes or the T-cell population in the gut and the other MAS susceptible related parameters could predict or prevent MAS susceptibility in broilers needs to be further investigated but can be interestingly for breeding programmes.
The impact of practically all the everyday stress factors occurring in the first days of the chick life on the rate of the utilisation of the yolk sac content, on the chicken immune status and on the growth of the animal's body and intestinal masses was investigated. The impact of the stress was investigated during the first five days of chick's life. The chicks were divided into five groups, each comprising 44 birds. The first chick group was exposed to moderate cold (2–3°C below the optimal temperature for the chick age). The second group was exposed to moderate heat (2–3°C above the optimal temperature for the age). The third and fourth group were deprived of feed and drinking water for 12 hours and 24 hour, respectively. The fifth chick group was the control group: the birds in this group had optimal environmental conditions and received feed and drinking water immediately upon entering the trial. Ten chicks were taken every day and weighed. Their blood samples were obtained for the assessment of infectious bursal disease virus antibody titres using ELISA method. After that, the birds were sacrificed, their intestinal masses weighed and the quantity of resorbed yolk measured.
The greatest body and intestinal masses were found in the control animals. The body and intestinal masses were the lowest in the group which was denied water and food for 24 hours. The resorption of the yolk sac content was approximately equal in all the chick groups, but the resorption rate varied by days. The highest resorption was observed in the chick groups on the day when feed was denied to them, so that this high resorption could be associated with the bird's body energy requirements. The resorption of the remaining yolk is associated with feed intake: in chicks to which feed is withheld the yolk is resorbed through the yolk sac wall directly into the blood, which increased its usability. When energy requirements are not satisfied, the chick's body probably utilises resorbed antibodies from the yolk remnants, as their glycoprotein composition is suitable for this purpose.
Beak trimming is routinely practiced in the poultry industry to reduce the incidence of feather pecking, aggression, and cannibalism in egg layers. Feather pecking is painful to birds and potentially induces cannibalism. Cannibalism happens in all current housing environments, cage- and free-production systems, and is one of the major causes of bird death in commercial laying hens without beak trimming. However, beak trimming has solicited a great deal of debate concerning the relative advantage and disadvantage of the practice and its impact on welfare. Abird's beak is a complex functional organ with an extensive nerve supply and various sensory receptors. Beak trimming may cause pain (acute, chronic, orboth) in trimmed birds due to tissue damage and nerve injury. The complexity and plasticity of the nervous system and the animal's inability to communicate verbally make pain difficult to measure directly. However, pain in animals can be recognized and assessed using physiological and behavioural parameters in response to noxious events. When evaluating whether an animal is experiencing pain, a distinction should be made between what an animal may feel and what a human observing the animal may feel. It should be noted that beak trimming-induced pain in birds is genetic-, lesion-, and age-dependent. Based on the updated information, the authorwould like to indicate that 1 with some genetic flocks of laying hens, if beak trimming is needed to prevent featherpecking and cannibalism, it should be conducted at hatchery oryoungerthan 10 days of age; 2 however, the most desirable approach is to eliminate beak trimming through a genetic selection of birds with less cannibalistic and aggressive tendencies, and 3 another solution is to develop an alternative means of trimming that has fewer painful implications and safeguards welfare before non-cannibalistic stocks are commercially available.
Oxidative rancidity represents one of the major causes of deterioration in food for human consumption. Besides producing unpleasant odours, it is responsible for losses in flavour, texture, consistency, appearance and nutritional value. In a similar way, in living animals, oxidative stress constitutes an important mechanism that leads to biological damage, and is regarded as one of the causes of several pathologies that affect poultry growth. Therefore a better understanding of lipid and protein oxidation processes will allow the use of antioxidants to handle and control them. This is fundamental in order to guarantee the quality and safety of meat for human consumption, and in turn the prevention and/or delay of several oxidation processes would allow its management for an optimal quality and shelf life conservation.
Their higher production performance and feed conversion efficiency make today's chickens more susceptible to heat stress than ever before. The increasing proportion of poultry production in tropical and subtropical regions makes it necessary to reconsider the long-term selection strategy of today's commercial breeding programmes. Also, the importance of the potential use of Naked neck and Frizzle genes is accentuated. Nutritional strategies aimed to alleviate the negative effects of heat stress by maintaining feed intake, electrolytic and water balance or by supplementing micronutrients such as Vitamins and minerals to satisfy the special needs during heat stress have been proven advantageous. To enhance the birds' thermotolerance by early heat conditioning or feed restriction seems to be one of the most promising management methods in enhancing the heat resistance of broiler chickens in the short run.
Bioactive peptides are specific protein fragments that positively impact the body's function or condition and ultimately may influence health. These peptides are inactive within the sequence of the parent protein and can be released during proteolysis or fermentation. They may exert a number of different activities in vivo, affecting cardiovascular, endocrine, immune and nervous system in addition to nutrient utilization. Hen eggs have traditionally been recognized as an excellent source of protein, vitamins and minerals. Research in the past decade, however, has produced a substantial amount of evidence indicating that hen egg proteins and peptides may exert several diverse biological effects, above and beyond fulfilling basic nutritional requirements. Several biological activities have now been associated with hen egg proteins, including novel antimicrobial activities, immunomodulatory, anti-cancer, and anti-hypertensive activities, highlighting the importance of hen egg proteins in human health, and disease prevention and treatment. Continued research to identify new and existing biological functions of hen egg proteins and their derivatives will help to define new methods to further improve the value of eggs, as a source of numerous biologically active compounds with specific benefits for human and animal health, and secure their role in the therapy and prevention of chronic and infectious disease.
Turkey meat production growth has been very dynamic since the 1970s. Global turkey stocks increased from 100M. to more than 276M. birds in 2004, in the same period the production volume increased from 1.2 to 5.1M. t. The growth in numbers of turkey stocks and turkey meat production shows remarkable regional differences. Even though North and Central America are still dominating this branch of the poultry industry, Europe could gain market shares. A high regional concentration can be observed in the turkey industry. In 2004 the ten leading countries contributed 79% of the global turkey stocks and more than 89% to turkey meat production. The regional pattern of turkey meat trade has changed considerably. France became the leading exporting country in the1980s; in 2003 the top three importing countries were Mexico, Russia and China. The regional concentration in turkey meat trade is also very high, in 2003 the ten leading countries contributed about 91% to the global export and 72% to the import volume. A major influencing factor behind the changing regional pattern of production and trade has been the development in the per capita consumption of broiler and turkey meat.
Proper cleaning and effective sanitation is an essential component of processing poultry, as it contributes significantly to the prevention of product contamination with microorganisms that cause food-borne disease and spoilage. Rapid expansion of production volume, increased further-processing and introduction of diverse ready-to-cook and ready-to-eat products, sophistication of the processing equipment, implementation of HACCP and microbial finished-product standards, and, more importantly, expensive product recalls have necessitated greater control over the cleaning and sanitation process.
A sanitary process should effectively protect raw and/or cooked products from physical (i.e. metal, plastic, bone, packaging materials etc.), chemical (residues of cleaning and disinfection chemicals, lubricants, coolants etc.), and biological (food-borne pathogens and/ortheirtoxins) hazards. In spite of this, many hazards continue to find their way into the processing environment and ultimately into the finished products. Microorganisms are naturally introduced into the poultry processing environments in high numbers with the live birds and, when the conditions are suitable, form growth niches by actively multiplying within the system.
It is generally accepted that processing equipment should not be a direct orindirect source of microbial contamination. Many regulatory and advisory bodies have introduced hygienic design and processing guidelines. This presentation will review the recently introduced sanitary processing equipment design principles and equipment checklist by the American Meat Institute.
Aplant designed, equipped, operated and maintained with internationally accepted hygienic and sanitary standards will produce safe and wholesome poultry products forthe consumer.
If proteins are the functional units of almost all biological processes, the proteome represents the set of proteins expressed in a cell at a given time and for given conditions. Because muscle is mainly composed of water and proteins, it seems evident that proteome analysis can give much information on structures and functions of proteins involved in several mechanisms which determine meat quality. This paper aims to present the most classical techniques (i.e. sample preparation and protein solubilisation, protein separation by 2-DE or SDS-Page, protein detection and quantification, computer analysis of 2DE-pattern and finally protein identification) that are currently applied to analyse the proteome.
Proteomic study related to meat quality are somewhat limited, especially in poultry, but some results are presented to illustrate how proteomic approaches can bring a new point of view on new or already known meat quality problems. It is the case in mammals where meat tenderness had been given a new highlight with proteomic study but also in turkeys where new hypothesis for explaining PSE meat syndrome can be developed from proteomic analysis. Some studies have also reported interesting results in muscle growth and development in chickens.
Meat quality is a complex problem which includes several factors of variation such as genetics, handling of animals during production, transportation and slaughter and also the handling of meat during product processing. Proteomic tools can give a new point of view on these problems and help the biologist to understand and finally resolve it.
Velvet beans (Mucuna spp.) represent a group of legumes that was widely grown in the U.S. in the 1800's and early 1900's before being replaced by soybeans. However today, in developing countries, the velvet bean plant is increasingly used as a cover crop because it has many valuable characteristics, such as resistance to insects, weeds and drought that make it economically useful to subsistence farmers. The velvet bean plant is also prolific in seed production, and velvet bean seeds (VB) or Mucuna are sometimes eaten both by humans and other non-ruminant, monogastric animals such as chickens and pigs. Mucuna beans contain moderate amounts of protein (20–25%) and smaller amounts of fat (3–5%). Non-structural carbohydrates make up approximately half of Mucuna while the neutral detergent fibre content is about 10%. Minerals and vitamins in VB can contribute significantly to the needs of poultry as is typical of many legumes. The various species of Mucuna have amino acid profiles similar to other legumes, such as soybeans, that are commonly used as protein-supplying feedstuffs. However, VB contain a variety of anti-nutritional/toxic factors that are harmful to monogastric animals. These include: antitrypsin factors; tannins; cyanide; anticoagulants; analgesic, antipyretic and anti-inflammatory factors; L-dopa and others. Research to date has studied the physiological effects of VB on poultry growth, blood chemistry and organ anatomy. Attempts have been made to process the beans and remove the toxic factors by heating, waterextraction or other methods but with limited success. To use such a potentially valuable feed ingredient in poultry nutrition, the challenge for the nutritionist is to find ways to diminish the harmful effects of the chemicals in Mucuna by processing or treating the beans to remove or render harmless the toxic chemicals. This review will summarize the history of these efforts.
This study was carried out on some epidemiological aspects and vector role of ticks infesting layers in Faisalabad (Pakistan). The prevalence of tick infestation was found as 11% (88/800), 24% (192/800) and 12.7% (413/3250) on Indigenous, Babcock and White Leghorn varieties of layers, respectively. Two species of ticks namely Argas persicus (10%; 485/4,850) and Argas vespertilionis (3.5%; 170/4,850) were recorded. Tick infestation was found higherin summermonths, in youngerbirds and in areas having densely located farms. The vector role of Argas persicus and Argas vespertilionis in the transmission of spirochaetosis in layer chicken was confirmed through isolation of Borrelia anserina from naturally infected ticks and their experimental transmission. Three species of bacteria namely Staphylococcus aureus, Salmonella pullorum and Escherichia coli were isolated from the triturated Argas persicus and Argas vespertilionis. Results of the present study were not different from those reported in literature, but for the first time in the study area. These results warrant for further research and also following effective tick control programs in orderto save the farmers from economic losses.