title: Microbial phytase addition resulted in a greater increase in phosphorus digestibility in dry-fed compared with liquid-fed non-heat-treated wheat-barley-maize diets for pigs.
abstract: The objective was to evaluate the effect of microbial phytase (1250 FTU/kg diet with 88% dry matter (DM)) on apparent total tract digestibility (ATTD) of phosphorus (P) in pigs fed a dry or soaked diet. Twenty-four pigs (65±3 kg) from six litters were used. Pigs were housed in metabolism crates and fed one of four diets for 12 days; 5 days for adaptation and 7 days for total, but separate collection of feces and urine. The basal diet was composed of wheat, barley, maize, soybean meal and no mineral phosphate. Dietary treatments were: basal dry-fed diet (BDD), BDD with microbial phytase (BDD+phy), BDD soaked for 24 h at 20°C before feeding (BDS) and BDS with microbial phytase (BDS+phy). Supplementation of microbial phytase increased ATTD of DM and crude protein (N×6.25) by 2 and 3 percentage units (P<0.0001; P<0.001), respectively. The ATTD of P was affected by the interaction between microbial phytase and soaking (P=0.02). This was due to a greater increase in ATTD of P by soaking of the diet containing solely plant phytase compared with the diet supplemented with microbial phytase: 35%, 65%, 44% and 68% for BDD, BDD+phy, BSD and BSD+phy, respectively. As such, supplementation of microbial phytase increased ATTD of P in the dry-fed diet, but not in the soaked diet. The higher ATTD of P for BDS compared with BDD resulted from the degradation of 54% of the phytate in BDS by wheat and barley phytases during soaking. On the other hand, soaking of BDS+phy did not increase ATTD of P significantly compared with BDD+phy despite that 76% of the phytate in BDS+phy was degraded before feeding. In conclusion, soaking of BDS containing solely plant phytase provided a great potential for increasing ATTD of P. However, this potential was not present when microbial phytase (1250 FTU/kg diet) was supplemented, most likely because soaking of BDS+phy for 24 h at 20°C did not result in a complete degradation of phytate before feeding.
authors.affiliation: Department of Animal Science,Aarhus University,Foulum,DK-8830 Tjele,Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Blaabjerg
authors.affiliation: Department of Animal Science,Aarhus University,Foulum,DK-8830 Tjele,Denmark.
authors.forename: A-M
authors.initials: AM
authors.lastname: Thomassen
authors.affiliation: Department of Animal Science,Aarhus University,Foulum,DK-8830 Tjele,Denmark.
authors.forename: H D
authors.initials: HD
authors.lastname: Poulsen
mesh_terms: D010832:6-Phytase / Q000494:pharmacology*; D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004063:Digestion / Q000187:drug effects; D005243:Feces; D005260:Female; D005511:Food Handling; D001467:Hordeum; D006358:Hot Temperature; D016226:Phosphorus, Dietary / Q000378:metabolism*; D010833:Phytic Acid / Q000378:metabolism; D013025:Glycine max; D013552:Swine / Q000502:physiology*; D014908:Triticum; D003313:Zea mays
chemical_list: D001426:Bacterial Proteins; D016226:Phosphorus, Dietary; D010833:Phytic Acid; D010832:6-Phytase
keywords: phosphorus; phytase; phytate; pig; soaking