Abstract: The aims of the present study were to assess the effects of ultra-stable copper sulfate and copper chloride hydroxide as copper sources on the stability of VA in piglet compound premix feed, and to evaluate the impacts of different storage temperatures on the stability of VA. This experiment was carried out with single factor test design method, and two treatment groups including ultra-stable copper sulfate group and copper chloride hydroxide group were set. The prepared samples in both groups were averagely divided into 9 parts and were placed at room temperature （n=3）, high temperature （n=3） and low temperature （n=3） environment, respectively. The VA content of all samples was detected every 8 days in a 32-day-long period from the start of the experiment （0 day）, and the loss rate of VA in compound premix feed of piglet at different storage time was calculated. The results showed that the loss rate of VA in ultra-stable copper sulfate group and copper chloride hydroxide group was increased with the extension of storage duration in normal temperature, high temperature and low temperature environment, and the loss rate of VA in ultra-stable copper sulfate group was significantly （P<0.01） lower than that in copper chloride hydroxide group at each detection time point; the loss rate of VA was elevated as the increase of storage environment temperature in both of the groups; the storage temperature had greater impacts on the loss rate of VA in piglet compound premix feed than copper sources did. In conclusion, ultra-stable copper sulfate had the effect of reducing the loss rate of VA in piglet compound premix feed, and it performed better than copper chloride hydroxide. Furthermore, the effect of temperature on the stability of VA was far greater than that of copper sources.

Key words: ultra-stable copper sulfate, copper chloride hydroxide, temperature, VA, compound premix feed, loss rate