25～48周龄海兰褐蛋鸡蛋氨酸供给量研究

本试验旨在研究25~48周龄海兰褐蛋鸡蛋氨酸(Met)供给量。试验选取整齐度92%、24周龄海兰褐蛋鸡720羽,随机分为6组,每组6个重复,每个重复20羽。试验采用玉米-豆粕型饲粮,对照组不添加DL-Met(Met含量0.25%),其余各组Met含量分别为0.31%、0.35%、0.39%、0.43%和0.47%。试验期24周。结果表明:1)随饲粮Met水平提高,蛋鸡产蛋率、日产蛋量显著提高(P0.05),料蛋比显著降低(P0.05),其中以0.35%和0.39%Met组效果较佳;平均日采食量及平均蛋重也有改善,但无显著差异(P0.05)。2)二次曲线分析显示,以产蛋率、日产蛋量和料蛋比为评价指标,试验期1~8周和9~24周蛋鸡Met供给量分别为0.36%和0.38%。3)试验4周,饲粮Met水平对血浆总蛋白(TP)含量无显著影响(P0.05);0.31%、0.39%和0.43%Met组血浆白蛋白(ALB)含量显著高于对照组(P0.05)。试验8周,饲粮Met水平对血浆TP、ALB和尿酸(UA)含量均未见显著影响(P0.05)。试验24周,饲粮Met水平对蛋鸡血浆TP和UA含量未见显著影响(P0.05)。结果提示,25~32周龄与33~48周龄海兰褐蛋鸡Met供给量分别为0.36%和0.38%。

Methionine Allowance for Hy-Line Brown Laying Hens Aged from 25 to 48 Weeks

The experiment was conducted to evaluate the allowance of methionine ( Met) for Hy-Line Brown laying hens from 25 to 48 weeks of age.Seven hundred and twenty Hy-Line Brown laying hens aged at 24 weeks were randomly divided into 6 groups with 6 replicates containing 20 hens each.The Met content of con-trol group without adding DL-Met was 0.25%, and Met levels for DL-Met addition groups were 0.31%, 0.35%, 0.39%, 0.43%and 0.47%, respectively.The experiment lasted for 24 weeks.The result showed as follows:1) The increase of Met levels significantly increased egg-laying rate and daily egg production ( P<0.05), decreased the ratio of feed to egg (P<0.05), and 0.35%and 0.39%Met supplemental groups got the better effects.The average daily feed intake and average egg weight were also improved but not significantly different ( P>0.05) .2) According to quadratic curve estimation of egg-laying rate, daily egg production, the ratio of feed to egg and average egg weight, the optimal Met allowance for laying hens was 0.36% and 0.38%, during the trial period from 1 to 8 weeks and from 9 to 24 weeks respectively.3) Dietary Met level did not affect plasma total protein ( TP ) content ( P>0.05 ) , but significantly increased plasma albumin ( ALB) content when Met at 0.31%, 0.39%or 0.43%level at the end of the fourth week compared with the control group ( P<0.05) .Dietary Met level did not significantly influence the plasma TP, ALB and urine acid (UA) contents at the end of the eighth week (P>0.05).Dietary Met level did not significantly influence the plasma TP and UA contents at the end of the twenty fourth week ( P<0.05) .Therefore, these overall results suggest that the allowance of Met for Hi-Line Brown laying hens aged from 25 to 32 weeks and from 33 to 48 weeks may be recommended at 0.36% and 0.38%, respectively.