Characterisation of European varieties of triticale with special emphasis on the ability of plant phytase to improve phytate P availability to chickens
Résumé
1. Thirty varieties and selection lines of triticale grown under similar conditions were characterised. Thousand grain weight, specific weight, Hagberg falling number and N were 50.2 ° 5.0 g, 72.4 ° 2.1 kg / hl, 96 ° 48 s and 16.1 ° 0.11 g / kg, respectively. 2. Mean P concentration was 2.86 ° 0.31 g / kg, of which 77% was of phytic origin (r = 0.60, P < 0.05). Mean phytase activity was 1018 ° 319 PU / kg. A genotypic effect on phytase activity was detected amongst five varieties studied out of thirty. Potential and real applied viscosities were positively correlated (r = 0.43, P < 0.05) and mean values were 3.53 ° 0.66 and 2.15 ° 0.31 mL / g, respectively. 3. The efficacy of plant phytase to improve P availability was assessed in chickens up to 3 weeks of age. Growth performance and bone ash concentration were compared in birds given either a maize (450 g/kg) and soybean meal (230 g/kg) phosphorus deficient diet containing 3.5 g P / kg, this basal diet supplemented with 1 or 2 g P / kg as monocalcium phosphate (MCP) or triticale (450 g/kg) and soybean meal (230 g/kg) diets containing 3.2 to 3.8 g P / kg with no MCP. To achieve graded levels of phytase activity four varieties of triticale, intact or in which phytase was denaturated by heat treatment, were used. Estimated metabolisable energy, protein, amino acids and calcium concentrations were similar in all diets. 4. Phytase activity in the triticale-based diets ranged between 135 to 1390 PU / kg. Growth performance and bone ash were responsive to plant phytase and to MCP. Non-linear models of these responses were adjusted with the best fit for bone ash parameters. 250, 500 and 1000 PU of plant phytase were estimated to be equivalent to 0.46, 0.67 and 0.81 g P as MCP, respectively.
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