| The purpose of this experiment is to study the effects of adding different levels of rare earth-chitosan chelate(RECC)in diet on the growth performance,intestinal indexes and meat quality of broilers,and to provide theoretical basis for the application of rare earth-chitosan chelate salts as a new green,safe and non-toxic feed additive in the production of broilers.A total of 192 1-day-old AA broilers with similar body weight were selected for the experiment and randomly divided into 4 treatment groups with 6 replicates,8 chickens in each replicate(half male and female).The control group was fed the basal diet,and the diets of addition groups were prepared by adding,respectively,150,200 and250 mg/kg of RECC to the basal diet.The experiment period was 42 days,divided into the starter period(1-21 d)and the finisher period(22-42 d),during which the experiment chickens had free access to feed and water.The experiment results were as follows:1.With the increase of RECC dose,FBW showed a significant linear increase effect during the starter and finisher periods(P=0.026;P=0.011).FE showed a significant linear increase effect during the finisher periods(P=0.016).During the trial period,FE showed a significant linear increase effect(P=0.024).The apparent metabolic rate of crude protein(CP)showed a significant linear increase effect during the starter period(P=0.034);the apparent metabolic rate of dry matter(DM)and crude fat(EE)showed a significant linear increase effect during the finisher period(P=0.029;P=0.018).2.With the increase of RECC dose,the duodenal chymotrypsin activity,lipase activity and trypsin activity in the late stage of the experiment showed a significant linear increase(P=0.020;P=0.038;P=0.029).Ileal chymotrypsin activity and jejunal lipase activity showed a significant quadratic increase effect(P=0.046;P=0.016);the activity of trypsin,lipase and amylase in jejunum showed a significant linear increase in the late stage of the experiment(P=0.046;P=0.011;P=0.042).3.With the increase of RECC dose,the jejunal villus height in the early stage of the experiment showed a significant linear increase effect(P=0.046),and the crypt depth showed a significant quadratic reduction effect(P=0.043);in the late stage of the experiment,there was a significant linear decrease in crypt depth of the duodenum and ileum(P=0.040;P=0.014).4.With the increase of RECC dose,the number of E.coli in the early stage of the experiment showed a significant quadratic reduction effect(P=0.017),while the number of E.coli in the late stage showed a significant linear reduction effect(P=0.029);the number of lactic acid bacteria showed a significant linear increase effect(P=0.012).5.With the increase of RECC dose,the hydrogen sulfide gas release in the early stage of the experiment showed a significant quadratic reduction effect(P=0.028),and the hydrogen sulfide gas release in the late stage showed a significant linear reduction effect(P=0.043).There was no significant dose-dependent effect between the amount of ammonia released and the amount of RECC added in the early and late periods.6.With the increase of RECC dose,the p H value of the pectoralis muscle and leg muscle at 24 h showed a significant linear increase effect(P=0.026;P=0.038),and the shear force and water loss rate showed a significant linear decrease effect.(P=0.028;P=0.033).From the above results,it could be concluded that adding RECC to broiler diets increased the activity of intestinal digestive enzymes,improved intestinal morphology and regulated the structure of microbial flora,thereby promoted the digestion and absorption of nutrients in broilers,improved growth performance,reduced the release of harmful gases in feces and improved muscle quality to a certain extent. |
