Studies On The Effects Of Microbial Phytase On Performance And Nitrogen Utilized Of Growing Pigs

A study was conducted to evaluate the effects of 500U/kg microbial phytasesupplementation in growing pigs on performance and nitrogen utilized.Experiment 1: One hundred healthy crossbred barrows (Duroc x Landrace x Large Youshire ) with an average weight of 20kg were randomly divided into four groups with five replicates (five pigs/replicate). Treatments were as follows: (1) control (feed basic diets); (2) basic diets plus 0.01% Phytase; (3) basic diets plus 0.48% MCP; (4)basic diets plus 0.48% MCP and 0.01% Phytase;. The gains were obtained on the 1st day, the 15th day and the 35 day of experiment. Then blood samples were collected from antechamber vein at 8:00 on the 35th day of experiment from five pigs randomly selected from each group. The serum Amino Acid concentration were measured.Expriment 2: Eight healthy crossbred barrows (Duroc x Landrace x Large Youshire ) with an average weight of 20kg were fitted with T-cannula at the distal ileum by surgeon, and were placed in the stainless metabolism cages, and fed experimental diets as experiment 1 according to two 4x4 Latin square designs. Each experiment period was comprised of 10 days with 5-d adaptation and 3-d collection of ileal digesta, fecal and urine samples to determine the concentrations of DM, OM, Nitrogen and Amino acids.The results showed that:(1) Comparing to the control group,500U/kg phytase supplemented to the diets can has the trend of improving the average daily feed intake (P>0.05). The diets with Phytase and MCP had no significant improvement on sows performance (P>0.05), but has the trend of improing ADG ADF and PCR (P>0.05).(2) Supplemention of phytase can improve 15 amino acids contents in the serum except His. Arg and Lys, but only Cys content has significant improvement (P<0.05); When Phytase and MCP were added to the diet, Thr. Arg. Asp and Pro contents in the serum were higher than the diet only with Phytase, especially Pro content in the serum has significant improvement (P<0.05).(3) 500U/kg phytase-supplemented diet significantly improved the apparent digestibilities of DM (P<0.01), CP(P<0.05) and OM (P<0.05) in the ileum and DM (P<0.01), OM (P<0.01) and CP (P>.05) in the feces. The digestibilities of DM, OM and CP in the ileum and the feces of the group supplemented phytase and MCP were higher than that of the group only with phytase.(4) Although the nitrogen retention of the diet with phytase was equal to the control, the nitrogen retention rate and the net nitrogen retention rate of which improved 8.81% and 9.02% than the control (P>0.05). Comparing to the control group, the nitrogen retention the nitrogen retention rate and the net nitrogen retention rate of the diets with Phytase and MCP had improved separatly 1.66g/d> 4.86% and 4.35%(P>0.05). (5) 500U/kg phytase-supplemented diet depressed the apparent digestibilities of Asp. Glu. Ala and Met in the feces (P>0.05) , and significantly improved the apparent digestibilities of Thr. Tyr and Ile in the feces (P<0.05), improved the apparent digestibilities of Lys. Arg. Leu. Gly. Pro. Phe and Ser in the feces but the difference was not significant (P>0.05);(6) Adding phytase improved the apparent digestibilities of His. Arg. Met. Tyr. He. Lys. Leu. Phe. Ala. Glu. Gly. Thr. Pro in the ileum ,but only the apparent digestibilities of His. Thr. Lys.Ile. Glu and Ala were significantly improved(P<0.05). Adding phytase depressed the apparent digestibilities of Val. Asp and Ser. The apparent digestibilities of Arg and Gly in the ileum of the diet with phytase and MCP were higher than that of the diet with phytase.(7) 500U/kg phytase-supplemented diet improved the true digestibilities of His. Lys. Ile. Leu. Phe. Ala. Tyr and Glu in the ileum.The true digestibilities of His. Thr. Ile. Glu were significantly affected (P<0.05). The true digestibilities of He in the ileum of the diet with phytase and MCP has significantly improvement (P<0.01). But the true digestibilities of Val and Ser of the diets with MCP or Phytase were depressed.