title: Effect of high-dose phytase and citric acid, alone or in combination, on growth performance of broilers given diets severely limited in available phosphorus.
abstract: 1. Two trials were conducted to evaluate the effect of high-dose phytase alone or in combination with citric acid (CA) in the diet severely limited in available phosphorus (P) on performance, plasma P and plasma Ca of broilers from 22 to 42 d of age. 2. In Trial 1, 297 21-d-old female chicks were placed into 27 pens and allocated to 9 maize-soybean meal-based dietary treatments, which were a positive control [PC, 4.23 g/kg non-phytate P (NPP)] and 8 negative control (NC, 1.35 g/kg NPP) groups consisting of two concentrations of CA (0 and 20 g/kg) and 4 concentrations of phytase (0, 1000, 2000 and 4000 U/kg) in a 2 × 4 factorial arrangement. In Trial 2, 192 21-d-old male chicks were placed into 24 pens and allocated to 6 wheat-canola meal-based dietary treatments, which were a PC (4.2 g/kg NPP), a NC (1.68 g/kg NPP) and 4 NC groups consisting of two concentrations of CA (0 and 20 g/kg) and two concentrations of phytase (2000 and 4000 U/kg) in a 2 × 2 factorial arrangement. 3. In both trials, birds fed on the PC had significantly higher average daily gain (ADG), average daily feed intake (ADFI), plasma P and lower feed conversion ratio (FCR) and plasma Ca than those of birds fed on the NC. CA supplementation significantly increased ADG and ADFI. There was a significant interaction between CA and phytase on plasma P where CA improved the effect of phytase on plasma P. In Trial 1, phytase addition improved ADG, ADFI, FCR and plasma Ca linearly. 4. Briefly, this research showed the interaction effect between CA and phytase on plasma P when broilers were fed on diets based on maize-soybean meal or wheat-canola meal. The results showed that CA supplementation lowered the concentration of phytase that is needed in low NPP diets to increase plasma P.
authors.affiliation: a Department of Animal Science, Faculty of Agriculture , University of Zanjan , Zanjan , Iran.
authors.forename: H R
authors.initials: HR
authors.lastname: Taheri
authors.affiliation: a Department of Animal Science, Faculty of Agriculture , University of Zanjan , Zanjan , Iran.
authors.forename: Z
authors.initials: Z
authors.lastname: Jabbari
authors.affiliation: a Department of Animal Science, Faculty of Agriculture , University of Zanjan , Zanjan , Iran.
authors.forename: S
authors.initials: S
authors.lastname: Adibnia
authors.affiliation: a Department of Animal Science, Faculty of Agriculture , University of Zanjan , Zanjan , Iran.
authors.forename: M H
authors.initials: MH
authors.lastname: Shahir
authors.affiliation: b Animal Science Research Institute , Karaj , Iran.
authors.forename: S A
authors.initials: SA
authors.lastname: Hosseini
mesh_terms: D010832:6-Phytase / Q000008:administration & dosage / Q000378:metabolism*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001937:Brassica / Q000737:chemistry; D002645:Chickens / Q000254:growth & development* / Q000378:metabolism; D019343:Citric Acid / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements / Q000032:analysis; D005260:Female; D008297:Male; D010758:Phosphorus / Q000097:blood / Q000172:deficiency*; D013025:Glycine max / Q000737:chemistry; D014908:Triticum / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry
chemical_list: D010758:Phosphorus; D019343:Citric Acid; D010832:6-Phytase