鸡饲料氨基酸消化率的测定及无氮日粮纤维水平对内源氨基酸排泄的影响

DETERMINATTON OF DIGESTIBILITY OF AMINO ACIDS IN POULTRY FEEDSTUFFS AND THE INFLUENCE OF FIBRE LEVEL IN NITRCOEN-FREE DIETS ON THE EXCRETION OF ENDOGENOUS AMINO ACIDS

试验用去盲肠成年公鸡和Ｓｉｂｂａｌｄ的真代谢能（ＴＭＥ）法，采用５×５拉丁方设计，测定了玉米、裸大麦、红苕干、菜籽饼、菜籽粕的氨基酸表观和真消化率；同时，采用４×４拉丁方设计，探讨了无氮饲粮纤维水平对内源氨基酸排泄量的影响。上述５种饲料必需氨基酸的平均表现消化率为６８．９９％、５４．２５％、１０．７３％、６４．２５％、５７．８２％无氮日粮估测的真消化率分别为９０．８２％、８１．７２％、６６．０９％、７９．５２％、７１．７２％。随着无氮饲粮酸性洗涤纤维水平的增加，内源干物质和氨基酸排泄总量呈线性增加（Ｐ＜０．０５）。不同合成纤维类型对肉源氨基酸的排泄有较大影响。不同方法（绝食法，６％醋酸纤维的无Ｎ饲粮及纤维水平的回归法）估测的内源氨基酸排泄量无显著差异。

Caecetomized cockerelswere used in a 5×5 Latin-square design to determine apparent and true digestibility of amino acids in maize, naked barley,dried sweet pctato, rapeseed meal(ext.) and rapeseed meal(sol.) with by the Sibbald's TME method. The effect of fibre levels and types in nitrogenfree diets on excretion of endogenous amino was also investigated in a 4×4 Lation-sqnare desing. The amino acid dsgestibilities were not significantly(P<0. 05) affected by the determination periods and animal groups. The average apparent and true digestibilities of the essential amino acids of the above feeds were 68. 99 and 90. 82, 54. 25 and 81. 72, 10. 73and 660. 9, 64. 25 and 79. 52, 57. 82 and 71. 72%,respectively. The amount of dry matter and amino acida in endogenous excretion increased linearly with increasing ADF levels in nitrogenfree diet (P<0. 05).The types of synthetic fibre had a significant effect on the amount of amino acid in endogenous excretion. The endogenous amino acid amount estimated by different metbods(starvation, nitrogen-free diet and regression method) was not significantly different.