Amino acid digestibility and energy metabolisability as affected by dietary calcium and supplemented phytase in caecectomised laying hens

作者：Agbede J O^*; Kluth H; Rodehutscord M

来源：Archiv fur Geflugelkunde, 2009, 73(2): 73-79.

• Calcium
• phytase
• caecectomised laying hens
• amino acids
• digestibility

The study aimed to assess the effect of a microbial 6-phytase on the digestibility of amino acids and its interaction with the Ca content of the diet in caecectomised laying hens fed low-P diets mainly based on maize, wheat gluten and sunflower meal. Effects on the utilisation of N, P, and Ca as well as energy metabolisability were also studied. The experiment followed a 2x2-factorial arrangement of treatments with 2 dietary Ca levels (adequate, ACa and reduced, LCa) either without (Phy-) or with (Phy+) phytase supplementation. The caecectomised laying hens aged 31 weeks were kept in balance crates, and 8 individual hens were allocated to each treatment in two periods. Hens were fed the treatment diets for 10 days, and excreta were quantitatively collected during the last 5 days. The Ca level did not affect AA digestibility. Phytase had an overall significant effect on AA digestibility. The difference between Phy+ and Phy- was 0.6%-units in ACa and 1.9%-units in LCa across all AA studied. Efficiency of N utilisation and energy metabolisability were significantly improved by phytase. LCa led to a reduced feed intake in comparison with ACa when the diets contained no phytase. Phytase significantly improved P utilisation at both Ca levels. It was concluded that phytase may be able to improve amino acid digestibility in laying hens fed on low dietary Ca levels. An interaction between the Ca level in the diet and supplemented phytase may be the reason for differences found in the literature about the effects of phytase on amino acid digestibility.

• 出版日期2009-4