09 Mar Renal Diseases in Poultry- A General Review, and Role of Phytogenics with Inorganic Salts
Renal diseases are common in avian species. In poultry birds, about 30% of all disease conditions are found to be directly or indirectly related to renal disorders. The main causes of kidney disorders in chickens are- nutritional deficiencies, managemental problems, toxins and infectious agents.
Gout
Gout is a sign and not a disease. In poultry, renal diseases lead to gout, which can further damage the kidneys or other body systems. It is a metabolic disorder resulting in hyperuricemia and the deposition of uric acid or urates in tissues. In broilers, it is usually found in the first 3 weeks of life than being later on.
The nutritional or metabolic causes of gout include- excessive dietary calcium, high protein diet, excess salt, low phosphorus, imbalance between Ca–P levels, adulteration of feed with urea, deficiencies of vitamin A and D, high altitude farming, water deprivation followed by over dosages of certain drugs like sulphas and the antibiotic aminoglycosides often causes kidney damage, managemental stress like, high brooding temperature and higher level of ammonia concentration in the shed can also cause high mortality due to gout, mycotoxins and phytotoxins, poisoning with phenolic disinfectants or insecticides, and infectious causes viz. bacteria (Salmonella, E.coli) and viruses (Infectious bronchitis virus (IBV), avian nephritis virus (ANV) and chicken astro virus.
The nutritional or metabolic causes of gout include- excessive dietary calcium, high protein diet, excess salt, low phosphorus, imbalance between Ca–P levels, adulteration of feed with urea, deficiencies of vitamin A and D, high altitude farming, water deprivation followed by over dosages of certain drugs like sulphas and the antibiotic aminoglycosides often causes kidney damage, managemental stress like, high brooding temperature and higher level of ammonia concentration in the shed can also cause high mortality due to gout, mycotoxins and phytotoxins, poisoning with phenolic disinfectants or insecticides, and infectious causes viz. bacteria (Salmonella, E.coli) and viruses (Infectious bronchitis virus (IBV), avian nephritis virus (ANV) and chicken astro virus.
In birds, Uric acid is the end- product of protein and purine metabolism and is normally excreted through Kidneys. Uric acid is insoluble in water andsince birds lack enzyme Uricase, there is no further conversion of Uric acid in to water soluble Allantoin, as in mammals. However, in birds, Uric acid is solubilised by binding with specific protein in the proximal tubules of kidneys so that its crystallization in kidneys is prevented. If there is renal failure or excessive formation of Uric acid in the body or both, due to various predisposing causes, Uric acid accumulates in the blood resulting in hyper Uricemia. Normal levels of Blood Uric acid in Birds is 4.5 to 5 mg/dl and when it rises to 10 -20mg/ dl, clinical symptoms of gout appear and when it rises to 25.5 – 42.2 mg/dl, there is severe gout mortality. High level of Uric acid in blood lead to precipitation of monosodium/ calcium urate crystals in various tissues and organs. These crystals, being insoluble in tissue fluids and having sharp ends, cause physical damage to the tissues leading to a cascading inflammatory reaction.
Gout is of 2 types- articular (random cases) and articular (most common and of economic importance):
a. Articular Gout: The accumulation of urates within the synovial capsules and tendon sheaths of the joints and ligaments, including the toes of the feet and wings. This is a chronic form and occurs sporadically. Mostly, roosters are affected. In articular gout, birds go lame; Urate deposits (Tophi) are found around periarticular tissue and also within joints of feet and legs. Joints of wings, spine and mandibles may also be similarly affected. Microscopically, granulomatous inflammation of soft tissue in these locations is marked.
b. Visceral Gout: The precipitation of uric acid crystals along the surface of internal visceral organs and other sites within the body. This is more acute- form and common form than articular gout and can affect the whole flock. It occurs in both sexes.Visceral gout presents no significant clinical signs and sudden onset and rise in mortality draws farmers› attention to the flock. Dead birds are dehydrated. In mild form ureters are thick, white and prominently seen. Kidneys appear pale with prominently visible uriniferous tubules. In severe form, in addition to these changes, white chalky deposits are found covering heart, liver, intestines, peritoneum, spleen lungs air sacs, muscles and inner lining of proventriculus. In few birds, such deposits may also be found in synovial sheaths of tendons, joints and subcutaneously on legs. Microscopically, inflammatory.
Necropsy Findings
Murexidase test on the deposits recovered from dead birds, confirms urate deposits. Blood uric acid estimation of the affected flock is alsoconfirmatory.
Gross lesions show swollen pale kidneys with urate deposits and dilated ureters with chalky white material surrounding the heart, kidneys, liver and other organs.
Microscopically, the kidneys show severe lesions characterized by moderate to severe tubular dilation, necrosis and large deposits of radiating fine needle shaped crystals in the tubular lumen and in the interstitium besides myocardium. These deposits were surrounded by a zone of granulomatous inflammation.
Economic Impact of Gout-
Gout has a direct effect on the productivity by lowering the weight gain of the birds, higher Feed Conversion Ratio (FCR) and mortality, which may go up to 11- 30%.
Prevention and Control:
- At hatchery level, minimize dehydration at all stages including chick holding and transport etc. Try to start chick life during daytime in cold weather when temperature is ideal.
- Maintain correct temperature at litter level during arrival of chicks and first 10 days at-least. Try to maintain 60- 70% humidity during first 3 days of chick life. Allow chicks to drink water for 1 or 2 hours and then only offer pre-starter feed.
- Ensure correct level of Calcium and Phosphorus levels in feed. Use toxin binders and liver tonics to keep minimum levels of fungal toxins in feed. Avoid excessive protein levels in diet.
- 4 Use recommended levels of aluminum-free Sodium bicarbonate in feed during high temperatures. Use electrolytes at recommended doses in water.
- 5 Review Infectious Bronchitis vaccine programme in Breeders and broiler farms. Even vaccine spray at hatchery level found to be effective in field condition.
- 6 High level of Methionine in feed also found helpful to some extent.
- 7 When gout is noticed, reduce the load on kidney by reducing the daily intake of protein either by reducing the quantity of feed or use grinded maize fortified with vitamins and salt at correct level for 24 to 48 hours along with uses of Ammonium sulphate or Ammonium chloride at correct levels.
- 8 Changes in the bird›s cage such as moving the food and water dishes to easily accessible locations and increasing the diameter of the perches may be helpful.
ROLE OF KLYRENIN COMBATING RENAL PROBLEMS
I. Sorbitol and Propylene glycol-
During the episode of gout, the birds undergo a phenomenal debility phase. Sorbitol and propylene glycol act as a ready source of energy to help maintain active feeding behaviour and encourage performance.
II. Potassium chloride and sodium bicarbonate-
During dehydration, the minerals K+, Na+ and Cl-play essential roles in maintaining osmotic balance, acid-base balance, and integrity of mechanisms that regulate the transport of substances across the cell membranes. The importance of Na+, K+ and Cl- levels in broiler diets is that, during stress, the competition between H+ and K+ in the renal tubules is reduced. During alkalosis, extracellular K+ enters the cell, consequently increasing the secretion of this ion in the renal tubule lumen. Under these conditions, H+ is exchanged by K+ in the renal tubule.
The increasing K+ secretion reduces its blood concentration, which causes circulation disorders in broilers, leading to death. Proper proportion among these minerals provides better electrolyte balance with the aim of maintaining physiological acid-base homeostasis, and thereby, optimal growth performance.
III. Magnesium sulphate
- a. Significantly increases haemoglobin value and decreases the H:L ratio in supplemented birds.
- b. Reduce the release of the catecholamines, norepinephrine and epinephrine.
- c. Significant effect on AST and ALT values and cholesterol level.
- d. Plays a role in 300 fundamental enzymatic reactions, including the transfer of phosphate groups, the acylation of coenzyme A in the initiation of fatty acid oxidation, and the hydrolysis of phosphate and pyrophosphate.
- e. Helps activation of amino acids, synthesis and degradation of DNA, and has a key role in neurotransmission. Also magnesium help in reducing corticosterone level and relieves birds from stress.
IV. Boldo (Peumus boldus molina) leaf extract has a pronounced antioxidant effect, and thus helps alleviate stress on the birds. It reduces the impact on growth parameters during gout episodes, promoting the growth of healthier microbes, reducing the creation of growth- depressing microbial substances, such as biogenic amines and ammonia, and increasing the availability of nutrients to the host. It increases lipogenesis in the liver, alleviate antioxidant enzymes (SOD, GPx ad MDA). The strong free radical scavenging and antioxidant activity of boldo leaves could be attributed to their high content of boldine and catechin. Boldine has been reported as the principal antioxidant alkaloid fraction, whereas, the total antioxidant activity of catechin, the main flavonoid compound, is estimated to be 60.9%.
V. Artichoke (Cynara cardunculus var. scolymus)– The major bioactive components of artichoke leaves are vitamin C, carotenoids, cynarin, flavonoids, phenolic acids, and caffeic acid. The artichoke extract (AE) has beneficial effects such as protection the hepatotoxicity in broiler chickens, reduction of blood urea, cholesterol and triglyceride in broiler chickens, improving the productive, reproductive performance and low cholesterol eggs, modulating the oxidative stability and meat quality of Japanese quail, and enhancing the immune functions in broiler chickens. Artichoke also improved feed conversion.
References:
– Esfandiary A. et al (2010) IJPS 9(3): 247-253.
– Gamba J.P. et al (2015) Braz J. Poul. Sc. 17(2): 237- 246.
– Ghanima M. et al (2019) Animals 2020, 10, 24.
– Lertpatarakomol R. et al (2015) Eur Sym Poult Nut., 220- 222.
– Rokade J.J. et al (2017) Anim. Nut. & Feed Tech. (2017) 17 : 13-23
– Sathiyaseelan et al (2018) Int.J.Curr.Microbiol.App.Sci. 7(7): 2414-2417.
