Pathogenesis Of Gout In Growers Induced By High Dietary Calcium

Visceral gout is the commonly and frequently disease in various caged and aviary birds from various parts of the world. Its mortality and mortality of gout reaches to 85% and 30% respectively. Many factors were suspected to be the causes of visceral gout. In China, many field reports have revealed that visceral gout was caused by excessive calcium. Furthermore, it is an economically important disease in the country. Many studies on the pathogenesis about gout induced by high dietary calcium have been carried out. However, its pathogenesis is still dimness.In the present study, according to the different experimental requirement, the different number of ISA growers of 35 days of old were randomly divided into four groups. The growers in different groups were fed with normal calcium and crude protein diet (control, 1.00% calcium and 17.53% crude protein), high calcium and normal protein diet (HC, 3.78% calcium and 17.42% crude protein), normal calcium and high protein diet (HP, 1.00% calcium and 24.52% crude protein) and high calcium and high protein diet (HCHP, 3.78% calcium and 24.25% crude protein) respectively. The experiment lasted 35 days. The clincopathology of serum and urine, dynamic change of some biochemical index, blood acid-base equilibrium, antioxdant function, renal injury, tht apoptosis of renal tubular cells, the expression of XOD and bcl-2 in renal in groers with gout induced by high dietary calcium were studied. Moreover, In vitro, the effect of high extracellular calcium on viability in primary cells culture of avian renal tubles and its mechanism were studied. The results are as follows.In experiment I, HC diet could cause gout, and typical visceral gout in growers was successfully induced by HCHP diet. As compared to the control and HP groups, the consumption of food in growers raised on the HCHP and HC significantly decreased. The rate of food and meet significantly increased. Inorganic phosphorus, potassium and magnesium decreased in the serum in the HC group, uric acid, calcium and sodium increased in the HC , uric acid and inorganic phosphorus increased in the HP, uric acid, calcium and sodium increased in the HCHP as compared with the control group. Growers raised on HCHP and HC diet had significantly higher urine pH and larger volume of urinethan that of the control and HP. The relative contents of calcium, sodium, potassium and magnesium and total quantity of 24-h urinary excretion of sodium for HC growers and HCHP growers were significantly lower when compared to the control and HP growers. The growers raised on HC and HCHP diet had significantly higher total quantity of 24-h urinary excretion of uric acid, calcium, magnesium, inorganic phosphorus, potassium in urine than that of the control. The relative contents of inorganic phosphorus and total quantity of 24-h urinary excretion of inorganic phosphorus and uric acid for HP growers were significantly higher when compared to the control growers. The growers raised on HP and HCHP diet had significantly higher relative contents of uric acid than that of the control and HC. Scanning electron microscope of urinary deposit showed that urinary deposit of control and HP group showed large amount of scattered spheres and little crystals of needlelike structure. Urinary deposit of high calcium group showed large amount of crystals of needlelike and little scattered spheres structure. Urinary deposit of high calcium and high protein groups showed large amount of crystals of needlelike and scattered spheres structure. X-ray energy dispersive spectrometer revealed that calcium, inorganic phosphorus increased and potassium, sodium, magnesium decreased in the urinary deposit in the HC group, meanwhile, phosphorus increased and calcium, potassium, sodium decreased in the HP and HCHP group as compared with the control group.In experiment II, the results showed HC could cause diarrhea at the day 15 after feeding the HC diet. As comared to the control, serum urine acid in the HC group increased at the day 24, 32 after feeding the HC diet. Serum calcium signi...