Phytase effects on the efficiency of utilisation and blood concentrations of phosphorus and calcium in Pekin ducks

Abstract

The objective was to study the effects of a supplementation of a 6-phytase 1 derived from the Peniophora lycii gene in the White Pekin duck. 2. In two balance studies, low-phosphorus (P) diets consisting mainly of maize, solvent 3 extracted soybean meal and solvent extracted sunflower meal were supplemented with 4 phytase up to concentrations of 1500 U/kg (Study 1) or 2000 U/kg (Study 2). Each diet 5 (phytase level) was fed to 8-10 individually penned ducks. The intake and excretion of each 6 animal was measured for 5 consecutive d when ducks were in their third week of life. Responses were described by nonlinear regression. 8 3. Although the basal diets from the two studies were similar in ingredient composition, 9 efficiencies of P utilisation (P accretion/P intake × 100) for the unsupplemented basal diets 10 were 39% in Study 1 and 30% in Study 2. Phytase supplementation significantly improved P 11 utilisation up to levels of about 55% in both studies. A plateau in P utilisation with an increase 12 in phytase supplementation was achieved in Study 2, but not in Study 1. The enzyme was 13 more efficient in Study 2 than in Study 1 at low rates of supplementation. Utilisation of 14 calcium (Ca) was significantly improved by phytase supplementation. Accretions of P and Ca 15 increased at a constant ratio. 16 4. In a 5-week growth study, diets with an intentionally marginal P level were used. Diets 17 were fed either unsupplemented or supplemented with 1000 or 10000 U/kg of phytase. Eight 18 pens of 10 sex-separated ducks each (4 pens per sex) were allocated to each dietary treatment. 19 5. Phytase significantly improved the growth of ducks of both sexes between d 1 and 21, but 20 not between d 22 and 35. Feed conversion rate was not affected by treatment. Blood serum 21 phosphate concentrations, but not calcium, were significantly increased by phytase 22 supplementation. Blood concentrations of creatinine, aspartate aminotransferase, and lactate 23 dehydrogenase remained unaffected while alanine aminotransferase was significantly reduced 24 by phytase supplementation. 25

Phosphorus equivalency value of an Escherichia coli phytase in the diets of White Pekin ducks

“…Likewise, FI of ducks on diets containing 500, 1,000, or 1,500 units of phytase per kilogram of diet increased by 6, 34, or 35%, respectively, relative to the NC diet. In a variety of studies, similar improvements in growth performance of ducks (Orban et al, 1999;Rodehutscord et al, 2003Rodehutscord et al, , 2006 or broiler chicks (Adedokun et al, 2004;Dilger et al, 2004;Pirgozliev et al, 2008) when low-P diets are supplemented with inorganic P or phytase have been reported.…”

“…Linear regression equations for the different dependent and independent variables for ducks fed a low-P negative control diet supplemented with graded levels of inorganic P or phytase from d 7 to 17 posthatch and calculated P equivalency values (g/kg of diet) of phytase al., 2009). In particular, improvement in P retention when phytase is added to low-P diets is well documented (Broz et al, 1994;Viveros et al, 2002;Rodehutscord et al, 2006) and is the main reason for supplementing the diets of nonruminant animals with phytase. The NC diet and those supplemented with inorganic P or phytase were formulated to contain similar Ca concentrations.…”

“…The enzyme phytase hydrolyzes phosphate groups from the phytin molecule potentially making this hydrolyzed P available for utilization in the body . The dietary addition of exogenous phytase has been shown to reduce P excretion through improving the utilization of phytate-bound P in pigs , broiler chickens (Dilger et al, 2004), and ducks (Orban et al, 1999;Rodehutscord et al, 2006).…”

Optimising the use of phosphorus sources in growing meat ducks

“…1 and 2 by Rush et al (2005). In two balance studies conducted by Rodehutscord et al (2006) this ratio was 1.6:1 and 1.9:1. In two balance studies conducted by Rodehutscord et al (2006) this ratio was 1.6:1 and 1.9:1.…”

“…Farrell et al (1993) supplemented duckling diets at 4.1 to 5.3 g total P/kg with 850 U/kg Aspergillus niger phytase and found an increase in P utilisation from 35 to 49% in 2 to 10 d old ducks and from 52 to 59% in 10 to 17 d old ducks. Phytase from Aspergillus niger and Peniophora lycii caused a nonlinear increase in the aP content of duck diets when supplemented in a range between 150 and up to 2,000 U/kg Rodehutscord et al, 2006). Phytase improved precaecal P digestibility and tibia ash content in some studies, but growth was not always positively effected, depending on the level of P supply and age (Martin et al, 1998;Orban et al, 1999;Attia, 2003).…”