Effect and Regulation Mechanism of Dietary Pi Content on Broiler’s Growth Performance and Phosphate Uptake
|School||Hunan Agricultural University|
|Keywords||Phosphorus absorption growth performance Na~+/Pi-Ⅱb broiler|
Inorganic phosphate (Pi) is the key nutritional factors, animals growing stage requires a lot of phosphorus in order to complete bone mineralization, and phosphorus also are essential components to other soft tissue and energy metabolism (such as phospholipids, nucleic acids and ATP) and plays an important role in normal function. In the aquaculture feeding industry, adding a lot of Pi can promote the growth of animals, but this will increase the cost of breeding, animal waste contains a large number of phosphorus can also seriously pollute the environment. In this paper, studies on phosphorus metabolism in broiler under different phosphorus levels in diets to further understand the molecular mechanism of phosphorus uptake and regulation of factors, and provide a reasonable scientific basis on dietary phosphorus adding.In Exp.1Studies on the influence of phosphorus level on growth performance, serum phosphorus and calcium and the absorption rate of phosphorus in guts.The total of120with similar weight evaluated20-day-old broilers were allotted to four treatments randomly, levels of dietary phosphorus of chickens were:0.4%,0.6%,0.8%and1.0%(grope0.6%was the matched group), there are five replicates of six broilers of each treatments. The results showed that the serum phosphorus levels of chicken were up as levels of dietary phosphorus increased, the lowest serum phosphorus was in0.4%dietary group, the highest was in1.0%dietary group, and both0.4%and0.6%,0.8%and1.0%phosphorus levels were significantly different (P<0.01).There were no significant differences on growth performance among the experimental groups. The activity of P transporters in the jejunum is significantly reduced with increasing dietary phosphorus level (P<0.01, whereas there was no significant differences in duodenum and ileum. The absorption rate of phosphorus in vitro of jejunum and duodenum of chickens forepart declined as dietary phosphorus increased, whereas there was unconspicuous changed in ileum of chickens. The absorption rate of phosphorus in duodenum or ileum in chickens was highest.In Exp.2Studies on the influence of phosphorus level on the intestinal abundance of Na/Pi-IIb mRNA.The sample from Exp.1were adopted in this trial which was cranked out as duodenum, jejunum and ileum. And the trial was to study effects of dietary phosphorus on intestinal abundance of Na+/Pi-IIb mRNA by real-time RT-PCR. The intent of this trial was to study the effects of diverse dietary phosphorus on the abundance of Na+/Pi-Ⅱb mRNA in different segments in small intestine in chicken. The results showed that High phosphorus inhibit Na+/Pi-Ⅱ b mRNA expression and low Phosphorus increased Na+/Pi-Ⅱ b mRNA expression in the small intestine; The Na+/Pi-Ⅱ b mRNA expression on different tissues in different segments is different, The Na+/Pi-Ⅱ b mRNA expression on jejunum of chickens were decreased with the level of dietary phosphorus increaded, ileum and duodenum no obvious trend.Conclusion:(1) Serum phosphoru levels in chicken are up as levels of dietary phosphorus increased;(2) Na+/Pi-Ⅱ b mRNA expression is effected by dietary phosphorus levels,high dietary phosphorus levels inhibited Na+/Pi-Ⅱ b mRNA expression levels;(3) Na+/Pi-Ⅱ b mRNA expression is different in different parts of different animal, intestinal segment in broilers with different phosphorus absorption level as follows:the duodenum, jejunum, ileum;(4) Dietary phosphorus level0.4%helps to improve the utilization ratio of phosphorus.