Metabolic Disorders in Commercial Broilers and Prevention Methods
The broiler sector is facing significant challenges as a result of metabolic disease, which is to blame for the high morbidity and death rates of chicken. The increased stress on the cardiovascular system caused by forced selection for quicker growth in broiler chickens predisposes the animals to metabolic disorders as ascites, sudden death syndrome, and limb paralysis. To solve these issues, we must concentrate on management techniques including providing a thermoneutral environment, modifying growth curves through feed restriction programmes and utilizing antioxidants. Due to the rapid rate of advancements in the genetic potential of chicken for development and efficiency, metabolic issues have been a constant in poultry production for at least the previous few decades. In broilers, metabolic disorders are more prevalent. Leg issues are frequently the outcome of rapid early growth and can therefore be associated to metabolic illnesses when they are observed in the absence of infectious agents. The key link between it and metabolic diseases in birds is an increased workload on the cardiovascular system. Cardiovascular disorders, which in broiler chickens cause a significant portion of flock mortality and musculoskeletal disorders, which cause less mortality but slow growth (thereby reducing profit) and cause lameness, which is still a significant welfare concern, are the two main body systems affected by poultry metabolic diseases.
Poultry Metabolic disease defined as abnormal conditions of physiological organs that originated from the metabolic pathway of poultry. It is occurred by excessive physical function without the primary involvement of infectious agents.
Common Poultry Metabolic Disease For Poultry
Metabolic diseases are associated with the metabolism of feed and other ingredients. The common metabolic diseases are
- Indigestion related to feeding,
- dysbacteriosis,
- cage layer fatigue,
- Fatty liver syndrome, (FLS)
- fatty liver, and kidney syndrome, (FLKS)
- Toxic Fat Syndrome ( Chick edema disease)
Etiology & Causal Agents of Gout
Avian Gout is a metabolic disease of poultry. Almost all dominated species affected by this disease. The most common species are broiler, laying hen, duck, turkey, etc.
The broiler is the most susceptible to avian gout compared to other species. Avian gout has a number of etiology & casual agent which cause gout in poultry. The casual agents of poultry can be divided into two sources. In this part, we can discuss non-infectious casual agents.
Non- Infectious
Although, infectious causes playing a vital role in inducing avian gout in poultry. If it is not distinguished properly, farmers became survive a lot facing uncontrollable mortality through the life cycle of birds.
Protein-rich feed
Poultry contains a balance of the amount of protein source either fish or animal origin.
If the feed contains a higher amount of protein, it is difficult to metabolize the amino acid as well as excreted from the body.
The by-products of a protein called uric acid. There are two types of amino acids responsible for creating uric acid in the body which are called purine & pyrimidine. If the supplied feeds contain excess protein, liver inducing uric acid from purine & pyrimidine.
Broiler FLKS (fatty liver and kidney syndrome)
The condition known as “fatty nephrosis” or “pink disease,” which affects the liver and kidneys, was originally identified in Denmark. It is a metabolic disorder that affects broiler and layer chicks between two and three weeks old due to a biotin deficit. Low levels of the biotin-dependent enzyme pyruvate carboxylase lead to minimal gluconeogenesis in the liver via pyruvate, which is the root of the issue. The liver’s glycogen reserves are quickly depleted and a deadly hypoglycemia develops when the bird experiences a modest stress such as extreme heat or cold, poor lighting, or a brief fast. The lipid content of the liver and kidneys has increased 2- to 5-fold, and the affected chicks are hyperlipemic, demonstrating a rise in the plasma levels of free fatty acids and triglycerides. Because chicken has limited access to the biotin found in wheat and some other cereals, there is a frequent correlation between wheatbased diets and fatty liver and renal disease. The condition is no longer present in broilers fed commercial diets due to enough dietary biotin’s ability to prevent FLKS.
Ascites
Ascites is brought on by an imbalance between the elimination and creation of peritoneal lymph, which results in a buildup of serous fluid in the body cavity and the condemnation or death of the corpse. The usual lesions that cause lymphatic drainage obstruction, decreased plasma oncotic pressure, increased vascular permeability, and increased hydrostatic pressure in the vascular system may also contribute to the pathogenesis of ascites. A right ventricular failure (RVF) or liver injury-related increase in portal pressure is the most common cause of ascites in birds. Fast growth rates increase the demand for oxygen, which increases the workload on the heart and predisposes broilers to developing pulmonary hypertension syndrome. As a result, fast-growing strains are more likely to develop ascites than slow-growing strains. Due to the rapid growth of chicken embryos during the final 7 days of incubation, which causes a 60% increase in oxygen consumption between the beginning of pulmonary breathing and hatching, maintaining adequate ventilation and oxygen supply in the hatcher and setters’ advice is necessary to control ascites and is also a useful method for enhancing the hatchability of broiler eggs. The need of temperature monitoring during brooding is highlighted by the fact that low temperatures increase the risk of ascites by raising pulmonary hypertension and metabolic oxygen demands. For the first 14 days following hatching, it is advised to feed a low protein/low calorie diet to the birds to control ascites. In broilers predisposed to ascites, increased levels of free radicals (super oxide anion radicals, hydroxyl radicals, hydrogen peroxide, and singlet oxygen) may accelerate the progression of the condition. Major antioxidant compounds like vitamin E, selenium, vitamin A, vitamin C, and glutathione play a crucial role in protecting damage at the cellular level, preventing the induction of hypoxia, and subsequently lowering the incidence of ascites. These compounds are present in the circulation or at the level of the respiratory membrane.
Sudden death syndrome
Sudden death syndrome (SDS), also known as “acute death syndrome” or “flip-over illness,” typically affects commercial broilers that are healthy and rapidly growing. As the name implies, birds with this condition exhibit abrupt death. When their growth rate is highest, bulkier male birds tend to develop this condition. Fast-growing broilers have more muscles than visceral organs, which are not proportionally developed. This results in an insufficient supply of oxygen to the muscles, which causes hypoxia. Lack of aerobic metabolism in hypoxic conditions results in increased lactate generation, which then causes systemic acidosis, a drop in blood pH and cardiovascular problems that ultimately lead to cardiac failure, which raises the risk of sudden cardiac death syndrome. Most infected broilers are discovered dead resting on their backs because SDS symptoms in birds include brief wing beating and spasms just before death. As a result, the illness is frequently called “Flip-Over Disease”. In comparison to intermittent lighting, broiler houses with higher feed intake and continuous lighting for extended periods of time have higher mortality from sudden death syndrome. SDS cannot be effectively treated or prevented, but its incidence can be decreased by management strategies that limit the early maximal development potential. By decreasing the number of daylight hours each day or by limiting the amount of feed consumed to 75% of what would be consumed if given the freedom to choose. During their first 14 days of life, broilers should be fed a lowprotein, low-energy diet to help them grow more slowly and with less oxygen demand, potentially reducing their risk of developing sudden death syndrome. Since the first seven days of a broiler’s life are crucial for optimal growth, the diet must remain unaltered throughout this time to ensure adequate growth. Thereafter, changes to the diet should be made carefully to prevent harm to the broiler.
Leg Issues
The prevalence of non-infectious limb issues such chondrodystrophy or angular bone abnormalities, valgusvarus deformities (often referred to as twisted legs), spondylolisthesis, or kinky back is likely connected to broiler chickens’ rapid growth. Longer periods of time are needed than are permitted by rapid growth for the development of robust tissue, bone remodelling, and alignment. By reducing feed consumption without raising the mineral concentration in the pre-starter diet, management strategies to lower metabolic illnesses are used, however this negatively affects healthy bone development and puts broilers at risk for various leg issues. Twisted legs and angular bone deformities are connected to rapid growth and seem to be caused by a lack of time for the distal tibio-tarsal bone to regenerate. By delaying early development and extending daily rest (dark) times, it can be decreased. Tibial dyschondroplasia is caused by a lack of vitamin D, which is essential for chondrocyte proliferation. The ratio of calcium to phosphorus in the diet also plays a critical role in determining the frequency and severity of the condition in broiler chicken. Vitamin D3 supplementation reduces the disease’s clinical symptoms primarily by triggering chondrocyte maturation.
Broiler hens’ spiking mortality syndrome
In this disease, birds are unable to stand or lift their heads, and it affects quickly growing broiler chickens with a sharp surge in mortality between 12 and 18 days of age. Death is mostly caused by hypoglycemia, which happened as a result of melatonin deficit owing to a lack of prolonged periods of darkness. Due to their higher pace of growth, males are more vulnerable than females.
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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PREVENTING POULTRY DISEASES THROUGH NUTRITIONAL INTERVENTION
