网上饲养密度对北京鸭免疫功能和氧化应激水平的影响

Effects of Stocking Density on Immune Function and Oxidative Stress Level of Pekin Ducks Reared on Plastic Wire-Floor

试验旨在研究饲养密度对22～42日龄网上饲养北京鸭免疫功能和氧化应激水平的影响。选取310只22日龄雄性北京鸭，随机分为5只／m^2（低）、8只/m^2（中）、11只/m2（高）的3个饲养密度处理组，每个处理5个重复。42日龄时进行屠宰采样，用于试验指标的测定与分析。结果显示：中、高密度组肉鸭的脾脏重量显著低于低密度组（P〈0．05）。总蛋白、球蛋白及免疫球蛋白G的含量随饲养密度的增加而显著升高（P〈0．05）。与低、高密度组相比，中密度组肉鸭肝脏总抗氧化能力、血清谷胱甘肽过氧化物酶活性和肝脏丙二醛浓度显著升高（P〈0．05）。结果表明：高饲养密度会加强北京鸭免疫系统的代偿反应，并使脾脏萎缩，而中饲养密度使北京鸭体内的氧化应激水平增加。建议北京鸭生长后期的网上饲养密度控制在5～8只，m^2。

The experiment was accomplished to study the effects of stocking density on immune function and oxidative stress level of Pekin ducks reared on a plastic wire-floor from 22 to 42 days of age. Male ducks （22 days of age,n=310） were randomly allotted into 3 stocking density groups of 5 ducks/m2 （low）,8 ducks/m2（medium）and 11 ducks/m2 （high）, with 5 replicates for each group. On 42 days of age, sample collection was conducted for analytical measurements. The results were showed as follows： Spleen weight was significantly decreased of Pekin ducks reared in medium and high stocking density than low density （P〈0.05）. Concentrations of total protein,globulin and IgG were significantly increasedwith the increasing of stocking density （P〈0.05）. Compared with low and high stocking density groups,levels of liver total anti-oxidative capacity, serum glutathione peroxidase and liver malondialdehyde were significantly increased in ducks of medium density group （P〈0.05）. This results indicated that high stocking density induced compensatory reactions of the immune system, and lead to spleen atrophy, while medium stocking density could increase oxidative stress level of Pekin ducks. Stocking density of Pekin ducks （22 to 42 days of age） reared on a plastic wire-floor should be limited between 5 to 8 birds/m2.