饲料锌在育肥猪粪尿中的排泄规律研究

为研究饲料锌在育肥猪粪尿中的排泄规律,建立饲料锌摄入量与锌排泄量的预测模型,试验选用健康、体重相近的约克夏去势育肥公猪20头,随机分成5组,每组4个重复,每个重复1头猪,单独饲养于代谢笼中。对照A组饲喂基础日粮,锌添加量为0,试验B、C、D、E组分别饲喂在基础日粮中添加20、40、60、80 mg/kg锌的试验日粮(硫酸锌形式)。预试期7 d,正试期4 d。结果表明:(1)与对照组相比,除试验B组外,其他试验各组风干粪锌含量和粪锌日排泄总量随日粮锌添加水平或日粮总锌水平增加显著升高(P<0.05);经回归分析,日粮锌添加水平或日粮总锌水平与风干粪锌含量和粪锌日排泄总量存在极显著的线性回归关系(P<0.01),可用所建立的回归方程进行预测和控制。(2)各组尿锌含量和尿锌日排泄总量均无显著差异(P>0.05);经回归分析,日粮锌添加水平或日粮总锌水平与尿锌含量和尿锌日排泄总量无显著回归关系(P>0.05)。综上,日粮中多余的锌主要通过消化道从粪中排泄,可根据日粮中锌水平预测粪锌排泄量,从源头上控制锌对环境的污染。

Study on excretion of feed zinc in feces and urine of finishing pigs

This experiment was conducted to study on excretion of feed zinc in feces and urine of finishing pigs and establish the prediction model of zinc intake and zinc excretion.A total of 20 healthy castrated Yorkshire finishing pigs with similar weight were randomly allotted to 5 dietary treatments with 4 replicatesin each treatment and 1 pig in each replicate,animals were individually housed in cages.In 5 treatments,control group A was fed a basal diet without zinc supplementation,test groups B,C,D,E were fed basal diet supplemented with 20,40,60,80 mg/kg zinc as zinc sulfate,respectively.The pre-test period lasted for 7 days,and the experimental period lasted for 4 days.The results showed that:(1)Compared with the control group,except for group B the air-dry fecal zinc content and daily fecal zinc excretion in experimental groups were significantly higher with feed zinc supplementation levels or feed zinc total levels being increased(P<0.05).Regression analysis demonstrated that there was extremely significant linear regression relationship between feed zinc supplementation levels or feed zinc total levels and air-dry fecal content or daily fecal zinc excretion(P<0.01).Therefore,regression equations could be established for prediction and control.(2)There were no significant differences in urinary zinc content and daily urinary zinc excretion among all groups(P>0.05).Regression analysis demonstrated that there was no significant regression relationship between feed zinc supplementation levels or feed zinc total levels and urinary zinc content or daily urinary zinc excretion(P>0.05).This experiment indicated that feed excess zinc was excreted mainly from feces though digestive tract.Therefore,fecal zinc excretion could be predicted based on feed zinc levels,so that mankind could control the pollution of zinc to environment from the source.