饲料锌在生长猪粪尿中的排泄规律研究.

【Objective】This experiment was conducted to study on excretion of feed zinc in feces and urine of growing pigs and establish the prediction model of zinc intake and zinc excretion.【Method】A total of 20 healthy castrated Yorkshire growing pigs with similar weight were randomly allotted to 5 dietary treatments with 4 replicates in 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 group B, C, D, E were fed basal diet supplemented with 20, 40, 60 and 80 mg/kg zinc as zinc sulfate, respectively. The pre-test period lasted for 7 days, and the experimental period lasted for 4 days.【Result】(i) The fresh fecal zinc content and air-dry fecal zinc content in experimental groups were higher than that in control group, with feed zinc supplementation levels being increased, both tended to be higher in the experimental groups. Fresh fecal zinc content, air-dry fecal zinc content and daily fecal zinc excretion in experimental group C and D were significantly higher than that in control group(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(P<0.01), in addition, there was significant linear regression relationship between feed zinc supplementation levels or feed zinc total levels and daily fecal zinc excretion(P<0.05). Therefore, regression equations could be established for prediction and control.(ii) 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).【Conclusion】 Under the condition of this trial, there was significant linear regression relationship between feed zinc supplementation levels or feed zinc total levels and air-dry fecal content or daily fecal zinc excretion, while 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, because 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. [ABSTRACT FROM AUTHOR]