Effects Of The Dietary Phosphorus Sources And Levels On Broiler Gowth Performance And Growth Performance And Tibia Quality Under Thiram-induced Condition

In this article, three trials were conducted to determine the effects of different phosphorus sources and dietary nPP levels on growth performance and tibia quality in broiers under thiram-induced condition.Expl Effects of the dietary phosphorus sources and levels on broiler growth performance and tibia quality during starter period (0to21d) under thiram-induced conditionDietary treatments consisted a2×3×2factorial arrangements with two phosphorus sources(DCP, MDCP), three levels of nPP(0.33%,0.48%,0.63%)and two levels of thiram(0,100mg/kg) for a total of12treatments.1200day-old cobb broilers were randomly assigned to the12treatments with5replicate pens of10male chickens per treatment. Thiram was fed to the birds during0-5d to induce TD. During6-21d, all the birds were fed the diets contained three levels of nPP(0.33%,0.48%,0.63%) without thiram based on the two phosphorus sources. The results were as follows:(1) MDCP significantly decreased TD scores at5d compared to DCP (P<0.05), and increased TD scores at21d (P=0.081). MDCP significantly increased tibia ash, Ca and P at5d (P<0.05). Interactions between phosphorus sources and levels for BW at21d, tibia ash at5d and21d were significant(P<0.05). MDCP0.33%nPP group increased BW at21d (P=0.056), tibia ash at5d and21d compared to DCP0.33%nPP group (P<0.05).(2) Increasing nPP levels would increase TD scores at5d and21d.0.33%nPP significantly decreased tibia ash, Ca and P at5d and21d when compared to0.48%nPP and0.63%nPP(P<0.05).0.48%nPP significantly increased serum PTH level compared to0.33%nPP at5d (P<.05), but no difference to0.63%nPP (P>0.05).(3) Thiram significantly decreased BW at5d and21d, FI during0-5d and6-21d, and significantly increased FG at0-5d (P<0.05). Thiram significantly increased TD scores at5d and21d (P<0.05). Thiram significantly decreased tibia Ca and P at5d, and tibia ash and Ca at21d (P<0.05), and decreased tibia ash at5d (P=0.098). Thiram significantly increased serum PTH, Ca and P levels at5d, and serum P at21d(P<0.05). Exp2Effects of thiram, phosphorus sources, and npp levels which were fed to the birds during0-21d on growth performance and tibia quality in broiler during22-42dThe treatments were the same as Exp1. All the birds were switched to the diets containing adequate nPP levels based on their initial phosphorus sources. Each treatment contained3replicates. The results were as follows; Growth performance had recovered among all treatments, but thiram still decreased the BW at42d (P=0.094). Thiram significantly increased the TD scores at42d and mortality during22-42d (P<0.05). MDCP significantly increased serum Ca level and decreased serum P level at42d (P<0.05).0.63%nPP significantly increased tibia length at42d (P＜.05).Exp3Effects of the dietary phosphorous sources on broiler growth performance and tibia quality during grower period (22to42d) under thiram-induced conditionThe experimental design consisted of a2×2factorial arrangement with two phosphorus sources (DCP, MDCP), two levels of thiram (0,100mg/kg) for4treatments. A total of12021-d-old AA broilers (at l-21d, half the borilers were fed DCP or MDCP diet respectively) were randomly assigned to the4dietary treatments according to initial weight. Each treatment was fed to3replicate pens of ten male chickens during22-42d while the the thiram diet was fed only at22-28d. The results are as follows:(1) TD scores of the birds from MDCP group were lower than the birds from DCP group at35d (P=0.093). Thiram significantly increased TD scores of the birds (P<0.05).(2) Tibia ash, Ca and P of the birds from MDCP group were significantly higher than the birds from DCP group under thiram-induced condition at35d (P<0.05). However, serum CT level of the birds from MDCP group was significantly lower than the birds from DCP group at35d (P<0.05). Thiram significantly decreased tibia ash, Ca and P level of the birds at28s and35d, and it also significantly increased serum Ca level at28d and35d, serum PTH level at28d (P＜O.05). MDCP slow down the development thiram-induced TD compared to DCP. Thiram caused hyperparathyroidism which lead to calcium homeostasis dysregulation in broilers.In conclusion, the diets supplemented with100mg/kg thiram during1-2Id and22-42d significantly increased TD scores, serum PTH and Ca levels, and signigicantly decreased tibia ash, Ca and P in broilers. It showed no significant differences on growth performance, and tibia ash, Ca and P but TD sorces were still significantly increased during22-42d when the birds were fed thiram during-5d. It showed no significant differences on growth performance and tibia quality between MDCP and DCP.0.33%nPP significantly decreased growth performance and tibia quality in broilers during1-21d compared to0.48%and0.63%nPP. However, growth performance and tibia ash had recovered when the birds fed with0.33%nPP were switched to the diets containing0.40%nPP. The interaction for tibia ash at5d and21d were significant between phosphorus sources and levels. On the condition of0.33%nPP, MDCP significantly increased tibia ash at5d and21d compared to DCP.