Effect of different dietary protein levels on growth performance and fecal and urinary excretion of Australian White growing sheep

LIANG Xiao-jiao; LIU Zhi-cheng; QIU Shu-chun; ZHANG Yu

doi:10.13557/j.cnki.issn1002-2813.2023.22.001

Abstract：The experiment aimed to investigate the effect of different levels of protein on growth performance,metabolic indicators and emission reduction benefits of Australian White growing sheep.Twenty-four Australian White growing sheep with similar growth status and weight(40.03±0.21)kg and in good health were randomly divided into four groups,with six replicates in each group and one sheep in each replicate.The growing sheep in control group were fed with a normal protein level daily diet(12.07%),while the growing sheep in experimental group Ⅰ were fed with a daily diet with a 1%reduction in standard protein,the growing sheep in experimental group Ⅱ were fed with a daily diet with a 2%reduction in standard protein,and the growing sheep in experimental group Ⅲ were fed with a daily diet with a 4%reduction in standard protein.The pre-test lasted for 10 d,and the formal test lasted for 30 d.The results showed that on 10～20 d,the growing sheep in the experimental group Ⅰ had the highest average gain.On 30 d,the experimental groups had the greatest reduction in fecal copper and urinary arsenic.The growing sheep in the experimental group Ⅱ had the greatest reduction in fecal nitrogen,fecal phosphorus,fecal chromium,urinary nitrogen,urinary phosphorus,and urinary copper.The growing sheep in the experimental group Ⅲ had the greatest reduction in fecal zinc,fecal cadmium,fecal arsenic and urinary zinc.The study indicates that feeding a daily diet with a 2%reduction in protein content can reduce nitrogen and phosphorus as well as heavy metal emissions without affecting growth indicators and reduce environmental pollution.