| The purpose of this experiment was to evaluate the effect of phytase in low phosphorus diets on growth performance, slaughter performance, tibia characteristics, organ index, serum biochemical parameters, digestive enzyme activity, apparent utilization of nutrients and NaPi-Ⅱb gene expression in jejunum of Youxian Sheldrake.A total of 350 7-day-old male Youxian Sheldrake were chosen and assigned randomly to five treatment.56 days trail period,early stage 7-28d and late stage 29-63d.The treatments include A-positive control(early and late stage nonphytate P(NPP)0.42%,0.38%), B-negative control(early and late stage nonphytate P(NPP)0.32%,0.28%),C-B plus 500U/kg phytase,D-B plus 750U/kg phytase,E-B plus 1000U/kg phytase.7-28d,the results were stated as follows:(1) Compared with group B,average daily gain(ADG) in group C、D、E were respectively increased by 6.5%(P>0.05),6.6%(P> 0.05),7.5%(P>0.05); average daily feed intake(ADI) in group E was significantly increased by 3.4(P<0.05);The F/G in group C、D、E were significantly decreased.(2) Compared with group B,serum UA level in group B、C、D were respectively significantly decreased by 38.1%、32.4%、48.3%(P<0.05),serum P level were respectively significantly increased by 42.9%、57%、61.5%(P<0.05),and the level of TP、BUN、serum Ca, ALP have insignificantly difference.(3) Phytase supplementation in low-phosphorus diets could improve tibia ash、Ca, P content(P<0.05);group E plus 1000U/kg phytase,the activity of amylase、lipase、trypsin were significantly increased(P<0.05).(4) Group E plus 1000U/kg phytase,the apparent utilization of DM、CP、EE、ME、 Ca and P were significantly increased compared with group B(P<0.05),and the apparent ileal amino acid utilization improved(P<0.05).29-63d,the results were stated as follows:(1) Compared with group B,average daily gain(ADG) in group C and E were respectively increased by 4.1%(P<0.05) and 8.2%(P<0.05), F/G in groupC、D、E were respectively decreased by 1.4%(P>0.05)、2.3%(P>0.05)、5.4%(P<0.05);and the organ index has a trend improved(P>0.05).(2) Compared with group B,serum BUN level in group C and E were respectively significantly decreased by 23.7% and 26.7%(P<0.05),ALP level in group C and D were respectively significantly decreased by 24.5% and 27.5%(P<0.05),Ca level in group E was significantly increased by 8%(P<0.05),P level in group B、C、D were respectively significantly increased by 13.4%、27.5%、26.2%(P<0.05); Compared with group A,P level in group B was decreased by 10.8%(P<0.05).(3) Group E plus 1000U/kg phytase and group D plus 750U/kg phytase in low-phosphorus diets could improve tibia ash、Ca、P content(P<0.05); group D plus 750U/kg phytase,the activity of amylase and sucrose were significantly increased(P<0.05).(4) Phytase supplementation in low-phosphorus diets could improve the apparent utilization of DM、CP and ME(P<0.05),and group E plus 1000U/kg phytase and group D plus 750U/kg phytase could improve the apparent utilization of P(P<0.05). Compared with group B, the apparent ileal amino acid utilization of His and Thr were significantly increased by 3.3% and 9.3%(P<0.05),and Asp、Cys、Pro and Ser were respectively significantly increased by 6.2%、21.5%、6.0% and 7.1%(P<0.05).(5) Compared with group B,phytase supplementation in low-phosphorus diets of Youxian Sheldrake could reduce the expression level of NaPi-Ⅱb gene in jejunum,and group E plus 1000U/kg phytase has better effection(P<0.05).Conclusion:(1) Phytase supplementation in low-phosphorus diets could reduce F/G, and improve the growth performance, slaughter performance, promote the development of organ;Improve the tibia characterizes and plasma parameteres, improve the activity of digestive enzymes and nutrient apparent availability.(2) Plus 1000U/kg or 750U/kg phytase in low-phosphorus diets could get the equal results compared with Group A in some target.(3) Phytase supplementation in low-phosphorus diets of Youxian Sheldrake could reduce the expression level of NaPi-Ⅱb gene in jejunum,and group E plus 1000U/kg phytase has better effection. |
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