| Zinc is the second most abundant trace element in animals and is widely added to animal diets.Compared with traditional zinc sources,nanometer zinc oxide has large specific surface area,a large number of active centers and strong chemical activity,which makes it possible to be an ideal substitute for common zinc sources in animal nutrition applications.The antibacterial activity of nano zinc oxide depends on its surface area and its concentration.The smaller the particle size is,the larger the specific surface area will be.Objects: This experiment took AA broilers as the research object to explore the effects of nanometer zinc oxide with different particle sizes on the growth performance,immune function and intestinal health of AA broilers,so as to provide an experimental basis for the in-depth study and scientific application of nanometer zinc oxide with different particle sizes in the dietary addition of broilers.Methods: 75 healthy and active 1-day old AA broilers were randomly divided into three treatment groups with 25 chickens in each group,namely:basic diet + conventional feed grade zinc oxide(NC group);Basal diet + zinc oxide with an average particle size of 82nm(ZNPL group);Basal diet +nanometer zinc oxide with average particle size of 2 1nm(ZNPS group);The experiment lasted 42 d.Blood,feces,intestinal organs and contents were collected for the following experiments: average daily gain(ADG),average daily feed intake(ADFI)and feed weight ratio(F:G)of test broilers were calculated;The spleen,thymus and Bursa of broilers were measured to record the growth index of immune organs.The content of zinc in broiler manure was detected.The serum indices,such as biochemical indices,inflammatory factors and antioxidant indices was measure d.Intestinal morphology was observed by H&E staining.Species diversity,abundance and evenness of intestinal flora were evaluated by 16 S RNA detection.Results:(1)Nano-Zn O could improve the growth performance of broiler chickens.The feed to meat rati o index in 21 nm nano-Zn O was significantly lower than that of the conventional Zn O group(P<0.05),showing a trend of particle size correlation.(2)In the detection of immune organ index,nano-zn O significantly promoted the development of spleen and thymu s(P<0.05,P<0.01),and showed a trend of particle size correlation.(3)Nano-Zn O significantly increased the content of serum metallothionin in broilers(P<0.05),and extremely significantly increased the content of lysozyme in broiler serum(P<0.01),showing a trend of particle size correlation.(4)In the detection of serum antioxidant index,nano zinc oxide could significantly increase the content of SOD in broiler serum(P<0.05);And the grain size is correlated.(5)In the detection of serum inflammat ory factors,nano-Zn O could reduce the gene expression levels of IL-6 and TNF-α in broiler serum,and increase the gene expression levels of IL-2 and IFN-γ,with a trend of particle size correlation.(6)In the detection of intestinal morphology of broiler s,the nanometer oxidation significantly increased the duodenum/jejunum/ileum density index(P<0.01),and the grain size was correlated.(7)In the indicator detection of intestinal flora,the species diversity,richness and evenness of the bacteria in the nanometer zinc oxide group were higher,and showed a grain size correlation.Conclusion: Nano-Zn O could improve the growth performance of broiler chickens,promote the development of immune organs,improve the non-specific immune ability of the body,and it also had anti-inflammatory effects,and could regulate the diversity,abundance and evenness of intestinal flora.The effect was closely related to the size of nanoparticles. |
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