title: Effects of microbial phytase supplementation on mineral utilization and serum enzyme activities in broiler chicks fed different levels of phosphorus.
abstract: An experiment was conducted to study the effect of microbial phytase (Natuphos 500) supplementation in chicks (0 to 6 wk of age) fed different levels of nonphytate phosphorus (nPP) on performance, mineral retention, bone and plasma minerals and serum enzyme activities. Data were analyzed as a 2 x 2 factorial arrangement with two levels of nPP for age periods of 1-d-old to 3 wk (0.35 and 0.22%) and 3 to 6 wk (0.27 and 0.14%) and two levels of phytase (0 and 500 U/kg) in each period. A positive control, adequate in nPP and Ca without phytase, was used. The low-nPP diets caused a negative effect on the performance (P < 0.05) compared to the normalnPP diet. Phytase had a favorable effect on weight gain at 3 wk (P < 0.004) and 6 wk (P < 0.0475) of age and on feed consumption only at 3 wk (P < 0.0106). Feed efficiency was not affected at any stage by addition of phytase. Performances of chicks fed with 0.35 and 0.27% nPP and phytase were comparable to those obtained with the normal-nPP diets. Decreasing nPP content in the diet increased (P < 0.0001) P retention at 3 and 6 wk of age, increased Mg retention at 6 wk, and decreased (P < 0.0001) Ca and Zn retentions at 3 and 6 wk, respectively. Phytase supplementation increased (P < 0.0001) Ca, P, Mg, and Zn retention at 3 and 6 wk of age. Likewise, the decrease in nPP content in the diet caused a significant reduction of tibia ash (P < 0.0023) and Mg content (P < 0.0001) in tibia ash and reduced liver (P < 0.0240), spleen (P < 0.0176), and tibia (P < 0.0001) weights. Similarly, Ca (P < 0.0369) and Zn (P < 0.0181) contents in tibia ash were increased in response to decreasing nPP levels in the diet. Phytase supplementation increased tibia weight (P < 0.0019), tibia ash (P < 0.0021), and Mg (P < 0.0339) and Zn (P < 0.0353) concentrations and reduced (P < 0.0161) the relative liver weight. By decreasing nPP levels in the diet, plasma Ca (P < 0.0001), Mg (P < 0.0001) and Zn (P < 0.0048) concentrations, and alkaline phosphatase (ALP) activity (P < 0.0299) increased, and plasma P content (P < 0.0001), aspartate aminotransferase (AST) activity (P < 0.0001), and total protein (TP) content (P < 0.0050) were reduced. Phytase supplementation increased plasma P level (P < 0.0001) and serum AST activity (P < 0.0049), reduced plasma Ca (P < 0.0001) and Mg (P < 0.0050) contents, and reduced serum alanine aminotransferase (ALT) (P < 0.0048), ALP (P < 0.0001) and lactate dehydrogenase (LDH) (P < 0.0192) activities. Plasma Zn was not affected by phytase supplementation. These results demonstrated that microbial phytase supplementation to low-P diets improved performance; P, Ca, Mg, and Zn use; and tibia weight and relative liver weight in broiler chickens. Likewise, serum AST, ALT, ALP, and LDH activities, as well as TP concentration, were also affected by phytase supplementation.
authors.affiliation: Departamento de Producción Animal, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Viveros
authors.forename: A
authors.initials: A
authors.lastname: Brenes
authors.forename: I
authors.initials: I
authors.lastname: Arija
authors.forename: C
authors.initials: C
authors.lastname: Centeno
mesh_terms: D010832:6-Phytase / Q000008:administration & dosage*; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism; D001842:Bone and Bones / Q000737:chemistry; D002113:Calcification, Physiologic; D002118:Calcium / Q000097:blood / Q000378:metabolism; D002645:Chickens / Q000254:growth & development / Q000378:metabolism*; D019587:Dietary Supplements; D004435:Eating; D004798:Enzymes / Q000097:blood*; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008274:Magnesium / Q000097:blood / Q000378:metabolism; D008297:Male; D008903:Minerals / Q000032:analysis / Q000378:metabolism*; D009929:Organ Size; D016226:Phosphorus, Dietary / Q000008:administration & dosage*; D013977:Tibia / Q000737:chemistry; D015430:Weight Gain; D015032:Zinc / Q000097:blood / Q000378:metabolism
chemical_list: D001798:Blood Proteins; D004798:Enzymes; D008903:Minerals; D016226:Phosphorus, Dietary; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D010832:6-Phytase; D008274:Magnesium; D015032:Zinc; D002118:Calcium