Effects of phytase on growthand slaughter performance,digestibility and nitrogenand mineral balancein heavy pigs

摘要

The study aimed at evaluating the effects ofphytase (Ronozyme~R NP) to the diet of fatteningpigs. In comparison with a control diet (C)which included 0.5% calcium salt (CaHPO4),two diets without CaHPO4 were tested: 150Phyand 300Phy, which contained 150 and 300 mgphytase/kg, respectively. Sixty barrows of about47 kg body weight (BW) each were randomlydivided into 3 groups of 20 animals each, everygroup split into 5 pens. Average daily gain(ADG), feed intake and feed conversion ratio(FCR) were registered. The trial was dividedinto 2 phases: 0 to 68 days (47 to 100 kg BW)and 69 to116 days (100 to 140 kg BW). Duringphase II, 6 pigs/diet were housed in individualmetabolic cages for the digestibility-balancetrial. Addition of phytase resulted in higher ADG(723, 783 and 772 g/d for C, 150Phy and 300Phy,respectively) and improved FCR (2.84, 2.64 and2.65) in phase I. No differences were registeredin phase II, though a better FCR was overallobserved. All slaughter parameters and the totaltract apparent digestibility (TTAD) of nutrients– except for calcium (Ca) and sodium (Na) –,were similar among treatments. Likewise, totalnitrogen (N) excretion did not differ acrosstreatments. Phosphorous (P) excreted for C,150Phy and 300Phy was 47.1, 53.3 and 52.5% ofthe P. Trace-minerals showed similar retentionsamong diets. Phytase effectively improvedgrowth performance until 100 kg BW at bothinclusion levels. Yet, it did not improve growthperformance, digestibility, N and P balance inheavier animals.