Effects Of Net Rearing On The Production Performance,Antioxidant Capacity And Immune Function Of Nonghua Ducks

In the duck industry,environmental pollution that caused by the traditional rearing method has already became a key factor restricting the development of duck industrial scale.As a more environmentally friendly rearing method,net rearing is an inevitable trend in the transformation of meat duck rearing method.However,previous researches were mostly focused on the effects of net rearing on duck production performance,whereas the effects of net rearing on antioxidant capacity and immune function has rarely been reported in duck.Therefore,this study taked the ground rearing method as a control,and thus aimed to explore the effects of net rearing on the production performance,antioxidant capacity and immune function of 4,8 and 13 weeks old Nonghua ducks.The results may be helpful for the selection of Ma duck rearing methodand provide reference for studying the impact of net rearing on duck health.The main results are as follows:1.Compared with ground rearing,4-week-old Nonghua ducks rearing on the net had smaller body size but longer neck length,and their slaughtering weight(rate)and half-eviscerated weight(rate)were significantly lower(P<0.05).The8-week-old Nonghua ducks rearing on the net had higher neck length,body length,0-8 weeks daily weight gain,live weight,carcass weight,half-eviscerated weight,eviscerated weight,sebum weight(rate)and abdominal fat weight(rate)(P<0.05),and had lower keel length,chest depth,slaughtering rate and leg muscle rate(P<0.05).The 13-week-old Nonghua ducks rearing on the net were with significant higher neck length,shank length,breast muscle rate,sebum rat and abdominal fat weight(rate)than ducks rearing on the ground(P<0.05),while their leg muscle weight(rate)were still significantly lower(P<0.05).2.The levels of serum ALT and ALP at the age of 8 weeks and serum AST,ALT and ALP at the age of 13 weeks of Nonghua ducks rearing on the net were significantly lower than those of ducks rearing on the ground(P<0.05).There was no significant difference in serum MDA content between the net and groud rearing ducks at the age of8 weeks,whereas the serum SOD activity was significantly lower in ducks rearing on the net rearing(P<0.05).The 13-week-old Nonghua ducks rearing on the net had significantly higher serum GSH-PX activity and MDA content(P<0.05).In addition,the results of q RT-PCR showed that the expression of liver GOT1 gene of the net rearing Nonghua ducks was significantly higher than that of the ground rearing ducks at the age of 8 weeks(P<0.05).3.Net rearing had significantly increased Nonghua ducks thymus weight and volume at the age of 8 weeks and spleen weight and index at the age of 13 weeks,but significantly decreased the bursal volume and index at the age of 8 weeks and the bursal index at the age of 13 weeks(P<0.05).Net rearing had significantly increased serum IFN-γ,IL-1β,IL-4,Ig A and Ig G levels at the age of 4 weeks,serum IL-1β level at the age of 8 weeks and serum IFN-γ,IL-1β,IL-4,Ig M levels at the age of 13 weeks(P<0.05),but only significantly decreased the serum IL-6 levels at the age of 4 and 13 weeks(P<0.05).q RT-PCR results showed that net rearing had significantly increased the expression of liver IFN-γ gene at the age of 13 weeks(P<0.05).In summary,net rearing was conducive to the advancement of time to market in Nonghua duck,but may reduce the leg muscle rate.In addition,net rearing could reduce the oxidative stress of Nonghua duck and improve the development of immune organs and the expression of immune factors and their blood content.