Effect Of Ascites Syndromes On Calcium And Phosphorus Metabolism And The Requirements Of Dietary Calcium Of Broilers

Three experiments were conducted to study the effects of ascites on calcium and phosporus metabolism, and dietary calcium requirements of broilers in normal or 3,3,5-triiodothyronine(T₃,1.5mg/kg) and low ambient temperature (LAT) stress condition. In Expl:An experiment was conducted to investigate the effect of ascites syndromes on calcium and phosphorus content of organ and availability of calcium and phosphorus. 120 Arbor Acres chickens of 1 day old were randomly divided into 2 groups(control group and T3 stress group) with 6 replicates of 10 broilers. T₃ and LAT could successfully induce AS of broilers, leading to 66.7% incidence and 23.3% mortality. Compared to control, AS significantly increased heart index of broilers (P<0. 05). The calcium content of heart, liver, duodenum were significant higher (P<0. 05), the phosphorus content of heart were obviously significant lower (P<0. 01) and duodenum were significant higher (P<0.05), the availability of calcium and phosphorus were obviously significant lower (P<0.01) . In conclusion the calcium deposit in tissue were changed by AS with the increase of calcium in heart, liver and duodenum, while the availability of calcium and phosphorus were decreased.In Exp 2: Effect of calcium on calcium phosphorus metabolism of broilers ascites syndromes. 2X5 factorial designs trial was conducted to invest the effect of high dietary calcium level (1.29%, 1.71%, 1.90%, 2.32%, 2.70%)on AS in normal and T₃ (1. 5mg/kg)stress condition. There were 10 treatments with 5 replicates and 10 broilers per replicate. The experiment period was 21 days. The results were as follows : (1) the incidence of AS was 18.5% and 42% in control and induced group, respectively. heart index of induced group was significant higher than that of control group (0. 23 VS 0. 20), and was affected significantly by the level of calcium (P<0. 05). (2) daily gain and daily feed intake decreased (P<0. 05) or P<0. 01) in induced group, and both were reduced with the increase of Ca in two groups. (3)the plasma K and P of induced group were significant higher than that of control group. the blood P was significantly affected(P<0. 01), the blood Ca and P were significantly affected by the interaction between T₃ and Ca (P<0. 05) and P<0. 01), respectively. the blood Ca showed up trend with Ca incontrol group .while downtrend in induced group, the blood P had a downtrend in bothgroups, but more faster in control group. (4) Availability of Ca had no difference inboth groups, availability of energy , fat and protein in induced group was marked decreasedthan that in control group (P<0. 01), availability of P was significant higher than thatin control group (P<0. 01). availability of Ca and P decreased with the increase of Calevel, availability of energy ,protein ,Ca and P were affected significantly byinteraction between T3and Ca (P<0. 01). the availability of Ca and P had a downtrendin both groups, but more faster in control group. (5) the tibia ash and P were significanthigher in induced group than that in control group (P<0. 01). ash ,Ca and P in tibiadecreased significantly with the increase of Ca level (P < 0.01). were affectedsignificantly by interaction between T3 and Ca (P<0. 05) or P<0. 01). Tibia ash and Cadecreased with the increase of Ca level in diet, but it was slower in induced group.(6) Caz+-Mg2*-ATP activity was higher in induced group (P<0. 05). Ca2Hlg2*-ATP activitywas affected by interaction between T3 and Ca (P<0. 05). conclusion: (1) T3 and LATcould successfully induce AS of broilers (2) In normal conditions, there were no effecton AS incidence when dietary calcium levels were 1. 29%². 70%. Growth performance weredecreased with dietary calcium levels increased. (3) Broilers could improve broilersphysiological condition although the bad effects of high calcium, when the levels ofcalcium were 1. 71%-—2. 32%, metabolism of calcium phosphorus were normal, the ratio ofAS were decreased.In Experiment 3: 2X4 factorial design trial were used to investigate the effect of AS on calcium requirement. In normal or T3(0, 1. 5mg/kg) stress condition, four dietary Ca levels(0. 7%, 1.0%, 1.25%,1.55%) were used. 320 l-d-old Broilers were allotted into 8 treatments with 4 replicates and 10 broilers per replicate. The experiment period was 21 days . the results were as follows (l) incidence of disease was in 10²2. 5% in control group and 35-85% in induced group. Heart index was significant higher in induced group(0. 27 VS 0. 22). (2) daily gain and daily feed intake were significantly decreased (P<0. 01) in induced group, and both were reduced with the increase of Ca in two groups, conclusion: AS increased significantly with the increase of Ca level (P<0. 05) . AS has no effect on the requirement of calcium.