饲粮铁水平对山麻鸭产蛋性能、蛋品质及肝脏和血液指标的影响

本试验通过研究饲粮铁水平对山麻鸭产蛋性能、蛋品质及肝脏和血液指标的影响,旨在探讨产蛋期(17~30周龄)蛋鸭对饲粮铁的需要量。选用15周龄的山麻鸭432羽,随机分为6个组,每组6个重复,每个重复12羽,单笼饲养。试验蛋鸭饲喂不添加铁的基础饲粮(含铁52.2 mg/kg)2周后,分别在基础饲粮中添加0、15、30、45、60、75 mg/kg的一水合硫酸亚铁(FeSO_4·H_2O),试验饲粮铁水平分别为52.2、67.2、82.2、97.2、112.2和127.2 mg/kg。试验期14周。结果表明:1)产蛋初期(17~18周龄),随着饲粮铁水平的提高,平均蛋重先升高后降低,其中饲粮铁水平为67.2、82.2和97.2 mg/kg组的平均蛋重显著高于112.2 mg/kg组(P0.05)。产蛋高峰期(19~30周龄)和试验全期(17~30周龄),饲粮铁水平对蛋鸭日采食量、产蛋率、平均蛋重、日产蛋重和料蛋比均无显著影响(P0.05)。2)随着饲粮铁水平的提高,蛋黄色泽呈先升高后下降趋势,饲粮铁水平为97.2 mg/kg组蛋黄色泽最高。3)肝脏铁含量随饲粮铁水平的提高而呈上升趋势,其中饲粮铁水平为127.2 mg/kg组的铁含量显著高于52.2 mg/kg组(P0.05)。4)随着饲粮铁水平的提高,肝脏过氧化氢酶(CAT)活性呈先升高后下降趋势,其中饲粮铁水平为67.2 mg/kg组CAT活性显著高于97.2、112.2和127.2 mg/kg组(P0.05)。饲粮铁水平对肝脏琥珀酸脱氢酶(SDH)活性无显著影响(P0.05)。5)血红蛋白浓度和红细胞压积随饲粮铁水平的提高而上升;饲粮铁水平为97.2、112.2和127.2 mg/kg组的血红蛋白浓度显著高于52.2 mg/kg组(P0.05),饲粮铁水平为112.2和127.2 mg/kg组的红细胞压积显著高于52.2 mg/kg组(P0.05)。6)以平均蛋重为指标,通过二次曲线模型的回归方程可获得产蛋初期山麻鸭饲粮适宜铁水平为73.9 mg/kg。综合考虑,建议产蛋初期山麻鸭饲粮铁水平为73.9 mg/kg,产蛋高峰期为52.2 mg/kg。

Effects of Dietary Iron Level on Laying Performance,Egg Quality,Liver and Blood Indices of Shanma Laying Ducks

To estimate dietary iron requirement for Shanma laying ducks in laying period ( from 17 to 30 weeks of age) , the laying performance, egg quality, liver and blood indices were examined.A total of 432 Shanma laying ducks at 15 weeks of age were randomly allotted to six groups, each with six replicates of twelve birds. All birds were offered a basal diet without iron supplementation ( containing 52.2 mg/kg iron) for 2 weeks. Then birds were fed the diets supplemented with 0, 15, 30, 45, 60 and 75 mg/kg FeSO4 · H2 O which con-tained 52.2, 67.2, 82.2, 97.2, 112.2 and 127.2 mg/kg iron, respectively.The experiment lasted for 14 weeks.The results showed as follows:1) in the early laying period ( 17 to 18 weeks of age) , the average egg weight was firstly increased and then decreased with dietary iron level increasing, and the average egg weight of 67.2, 82.2, 97.2 mg/kg groups was significantly higher than that of 112.2 mg/kg group ( P<0.05) .While in the peak laying period ( 19 to 30 weeks of age) and the whole experimental period ( 17 to 30 weeks of age) , no significant differences were observed in daily feed intake, egg production, average egg weight, egg mass, and feed/egg (P>0.05).2) The yolk color was firstly increased and then decreased with dietary iron level increasing, and the maximal value was at the level of 97.2 mg/kg.3) The liver iron content was in-creased with dietary iron level increasing, and the liver iron content of 127.2 mg/kg group was significantly higher than that of 52.2 mg/kg group ( P<0.05) .4) The liver catalase activity was firstly increased and then decreased with dietary iron level increasing, and the liver catalase activity of 67.2 mg/kg group was significant-ly higher than that of 97.2, 112.2 and 127.2 mg/kg groups ( P<0.05) .There was no significant difference in liver succinodehydrogenase activity amomg groups ( P>0.05) .5) Both hemoglobin concentration and hemato-crit were increased with dietary iron level increasing, the hemoglobin concentration of 97.2, 112.2 and 127.2 mg/kg groups was significantly higher than that of 52.2 mg/kg group ( P<0.05) , and the hematocrit of 112.2 and 127.2 mg/kg groups was significantly higher than that of 52.2 mg/kg group ( P<0.05) .6) Accord-ing to the quadratic regression model of average egg weight, the iron requirement for Shanma laying ducks dur-ing early laying period was 73.9 mg/kg in the diet.On the basis of above results, iron requirement are 73.9 and 52.2 mg/kg iron in the diet of Shanma laying ducks during their early and peak laying period, respectively.