本试验旨在研究饲粮赖氨酸水平对产蛋高峰期(30~38周龄)临武鸭生产性能、蛋品质、血清生化指标及氮代谢的影响,以确定产蛋高峰期临武鸭赖氨酸需要量。试验选取体重相近、健康状况良好、产蛋率无显著差异(P>0.05)的临武鸭200羽,随机分为5组,每组5个重复,每个重复8只鸭。饲粮中赖氨酸水平分别为0.65%、0.75%、0.85%、0.95%、1.05%,试验期63 d。在饲养试验结束后,每组挑选出10只体重接近各组平均体重的试验鸭进行代谢试验。结果显示:1)0.95%和1.05%赖氨酸组日产蛋重显著高于0.65%和0.75%赖氨酸组(P<0.05),而0.95%和1.05%赖氨酸组料蛋比显著低于0.65%和0.75%赖氨酸组(P<0.05)。2)饲粮赖氨酸水平对蛋品质无显著影响(P>0.05)。3)0.85%、0.95%和1.05%赖氨酸组血清总蛋白含量显著高于0.65%赖氨酸组(P<0.05)。0.95%赖氨酸组血清中三碘甲腺原氨酸含量显著高于0.65%、0.75%和1.05%赖氨酸组(P<0.05)。4)0.95%赖氨酸组净蛋白质利用率和氮沉积量显著或极显著高于0.65%赖氨酸组(P<0.05或P<0.01)。5)二次曲线分析表明,以总蛋白、净蛋白质利用率和氮沉积为评价指标,产蛋高峰期临武鸭饲粮中赖氨酸需要量分别为0.92%、0.96%和0.95%。由此可见,30~38周龄临武鸭的日产蛋重、料蛋比、总蛋白、净蛋白质利用率和氮沉积对于饲粮中赖氨酸水平的变化较为敏感,而获得较佳的生产性能、血清生化指标和氮平衡的适宜赖氨酸水平为0.92%~0.96%。

This experiment was conducted to study the effects of dietary lysine (Lys) level on performance, egg quality, serum biochemical indices and nitrogen metabolism of Linwu ducks in peak laying period (30 to 38 weeks of age), and to evaluate Lys requirement of Linwu ducks during the peak laying period. A total of 200 healthy Linwu ducks with nearly same body weight and laying rate (P>0.05) were randomly assigned to 5 groups with 5 replicates in each group and 8 ducks in each replicate, and fed basal diet supplemented with 0.65%, 0.75%, 0.85%, 0.95% and 1.05% Lys for 63 days, respectively. Ten ducks per group were picked up on the basis of individual weight immediate to the average weight of every group at the end of the feeding experiment, and the ducks were used in metabolism experiment. The results showed as follows:1) The daily egg weight in 0.95% and 1.05% Lys groups was significantly higher than that in 0.65% and 0.75% Lys groups (P<0.05), but the feed/egg in 0.95% and 1.05% Lys groups was significantly lower than that in 0.65% and 0.75% Lys groups (P<0.05). 2) Dietary Lys level had no significant effects on egg quality of laying ducks (P>0.05). 3) The serum total protein content in 0.85%, 0.95% and 1.05% Lys groups was significantly higher than that in 0.65% Lys group (P<0.05). The serum triiodothyronine content in 0.95% Lys group was significantly higher than that in 0.65%, 0.75% and 1.05% Lys groups (P<0.05). 4) Compared with 0.65% Lys group,the net protein utilization (NPU) and nitrogen deposition in 0.95% Lys groups were significantly improved (P<0.05 or P<0.01). 5) According to the quadratic regression analysis based on total protein, NPU and nitrogen deposition, the optimal dietary Lys levels for Linwu ducks were 0.92%, 0.96% and 0.95%, respectively. In conclusion, the daily egg weight, feed/egg, total protein, NPU and nitrogen deposition of Linwu ducks aged from 30 to 38 weeks are more sensitive to changes of dietary Lys level. The optimal dietary levels in diet of Lys for Linwu ducks is 0.92% to 0.96%, that can obtain the best performance, serum biochemical indices and nitrogen metabolism.