Effect Of Phytase And CaHPO₄ On Performance And Nutrient Apparent Digestibility Of Growing-finishing Pigs

Two experiments were conducted to study the effect of phytase and CaHPO4 on performance and nutrient digestibility of growing-finishing pigs.Experiment 1:Fifty-six healthy crossbred barrows(Landrace×Yorkshire) were divided into eight groups with seven replications and one pig in each replication randomly. The treatment was showed as the feed of growing phase-the feed of finishing phase.And the treatments were NP-NP, NP-LP, LP-NP,LP-LP,NPP-NPP,NPP-LPP,LPP-NPP,LPP-LPP. The results were as followed: (1) During the growing phase:The performance of LP was significantly lower than NP.The performance of treatments added phytase was significantly higher than the treatment of no phytase.The performance of LPP was no significantly with the treatment of NP.(2) During the finishing phase: The performance of LP was significantly lower than NP. The performance of NPP were no significantly with NP.The performances of LPP was significantly higher than LP.There were no significantly between NP and LPP. (3) During the growing-finishing phase:The performance of all the phytase supplement treatments were no significantly with NP-NP;the performance of all the phytase supplement treatments and NP-NP were significantly with NP-LP, LP-NP and LP-LP; the performance of NP-LP and LP-NP were significantly higher than LP-LP .The conclusion:Phytase addition to low phosphorus diets could improve the performance of growing-finishing pigs; Phytase addition to normal phosphorus diets did not improve the performance of finishing pigs;The diets of no CaHPO4 decreases the performance of growing-finishing pigs.Exp2:Fifty-six healthy crossbred barrows(Landrace×Yorkshire) were divided into four groups with fourteen replications and one pig in each replication randomly. They were feeded as normal phosphorus diets(NP),low phosphorus diets(LP),normal phosphorus added phatse diets(NPP), low phosphorus added phatse diets(LPP).The results were as followed:(1)During the growing phase:The apparent digestibities of CP (CPAD) and excretion of CP did not differ between LP and NP.The apparent digestibities of Ca(CaAD) did not differ between LP and NP,but excretion of Ca was lower in pigs fed LP(P<0.01). The apparent digestibities of P(PAD) and excretion of P were lower in pigs fed LP compared with NP(P<0.01,P<0.05). The CPAD and excretion of CP did not differ between NP and NPP.The CaAD was greater(P>0.05) and excretion of Ca was lower(P<0.01) in pigs fed NPP compared with NP. The PAD was greater(P<0.01) and excretion of P was lower(P>0.05) in pigs fed NPP compared with NP. The CPAD and excretion of CP did not differ between LP and LPP. The CaAD and excretion of Ca were greater in pigs fed LPP compared with LP(P<0.01,P<0.05). The PAD and excretion of Ca were greater in pigs fed LPP compared with LP.(2) During finishing phase: The CPAD and excretion of CP did not differ between LP and NP. The CaAD and PAD was lower in pigs fed LP compared with NP(P>0.05,P <0.01). The excretion of Ca and P was lower in pigs fed LP compared with NP(P<0.05,P <0.01). There are no significant different in apparent digestibilities and excretion of CP,Ca and P. The CPAD and excretion of CP did not differ between LP and LPP,The CaAD and PAD were greater in pigs fed LPP compared with LP(P <0.01), The excretion of Ca and P was lower in pigs fed LPP compared with LP(P >0.05,P <0.05). The conclusion: Phytase addition to low phosphorus diets could improve the apparent digestibility of Ca and P on growing-finishing pigs;Diets of no CaHPO4 could decrease the apparent digestibility of Ca and P on growing-finishing pigs.