Effects Of Cool Temperature And Vitamin E On Production And Biochemical Indexes Of Cage-rearing Laying Ducklings

This experiment aims to study the effect of cool temperature on ducklings, and the effect ofvitamin E on animal growth promotion and cool temperature slowing up, in respect to productionperformance and biochemical indexes. The research will provide theory basis for productionpractice.In this experiment, 1-day-old laying ducklings numbered 180 were randomly divided into 6disposals, with 6 repetitions in each disposal and 5 ducklings in each repetition. Set twotemperature levels, which are moderate temperature and cool temperature. Moderate temperatureswere controlled at 33～30℃in 1st～7th day, at 30～28℃in 8th～14th day, at 27～25℃in 15th～21st day, and at 24～21℃in 22nd～28th day, respectively. As for cool temperatures, they were setidentically with those in moderate temperature duck sheds in the first three days. From the fourthday, they were controlled as 5±1℃lower than corresponding moderate ones, which were at 28～25℃in 4th～7th days, at 25～23℃in 8th～14th days, at 23～21℃in 15th～21st days, and at 21℃in 22nd～28th days, respectively. Both moderate and cool temperatures were gradually decreased,and at 21℃in 28th day. Daily dietary was set into three VE levels (20 IU/kg, 220 IU/kg, and 420IU/kg) for six disposal groups, which were Group First(VE 20 IU/kg in moderate temperature),Group Second(VE 220 IU/kg in moderate temperature), Group Third (VE 420 IU/kg in moderatetemperature), Group Fourth (VE 20 IU/kg in cool temperature), Group Fifth EvE 220 IU/kg in cooltemperature), Group Sixth (VE 420 IU/kg in cool temperature).The period of the experiment was 4 weeks, during which both ducklings and excess feeds wereweighed once per week, and daily weight gain and food conversion ratio were calculated. In the 21stday, 1 duckling was randomly selected from each repetition of separated experiment groups. Bloodwas sample from their jugular veins, and biochemical indexes were measure after serum wasseparated.It was shown from results of production experiment that cool temperatures obviously affect thedaily weight gain, feed intake, and feed weight ratio of laying ducklings. Meanwhile, VE additionlevels at both 220 IU/kg and 420 IU/kg can effectively improve daily weight gain and feedefficiency(P＜0.05) in either moderate or cool temperatures, but 220 IU/kg was preferable.It was shown from biochemical indexes, cool temperature had obvious effects on contents ofcalcium, natrium, chlorine, total protein, and globulin, each of which was higher than that in moderate temperature. Cool temperature obviously reduced alkaline phosphatase activity (P＜0.05).Cool temperature obviously affected urea nitrogen, which was obviously higher than that inmoderate temperature(P＜0.05). The content of glucose and triglyceride were obviously higher inthe cool temperature than that in moderate temperature. The content of triglyceride increased in thehigh vitamin E level no obviously. Serum Total Antioxidant Capacity increased significantly as thelevel of the dietary vitamin E increased. The content of T₄ was higher in the cool temperature thanthat in moderate temperature (P＜0.05). The vitamin E level of 220IU/kg had significant effect inincreasing the content of T₄.Known from change analysis of production performance and biochemical indexes, VE additionamount of 220 IU/kg is preferable for cage-rearing ducklings in cool temperature environment.