Effects Of Rare Earth-Chitosan Chelate Added To Laying Hens On Growth Proformance And Nutrients Utilization

Rare earth-Chitosan Chelate is a new feed additive,which is made by chelating rare earth ions and chitosan molecules.450 27-week-old layer chickens,with similar body weight and healthy,were randomly alloted into five treatments.The laying hens in this experiment were fed six dietary levels of rare earth-chitosan chelate supplement(control: 0%;treatⅠ:0.05%;treatⅡ:0.1%;treatⅢ:0.15%;treatⅣ:0.2%).The experiments were carried out to study the effects of rare-earth chitosan on growth performance,blood serumindices,utilization of nutriment and activation of digestive enzyme in layer chickens,in order to prove the additive efficiency of rare-earth chitosan and the possible mechanism of rare earth-chitosan chelate.The results show that:1.With the addition of rare earth-chitosan chelate increased,the rate of egg production raise gradually.When the additive amounted to 0.2%,the rate of egg production reached a peak(P＜0.01).Average of egg weight and average of egg weight everyday in treatⅣ,compared with control group,increased 0.73%(P＜0.01)and 6.83%(P＜0.05).Compared with control group,groupⅡ,ⅢandⅣimproved the apparent utilization of dry matter and Ca significantly(P＜0.05),groupⅣimProved the apparent utilization of crude protein significantly(P＜0.05).The apparent utilization of P had no significant difference among groups(P＞0.05).2.In contrast with control group,egg cholesterol in treatⅣreduced 32%significantly(P＜0.05).Egg weight,hangh unit,egg shape index,eggshell intensity,eggshell thickness and egg yolk color had no significant difference among groups.With the increasing of rare earth-chitosan chelate in different levels,triglyceride and cholesterol in treat group improved gradually firstly,which would reduce gradually in later stage.Compared with control group,groupⅡimproved the content of triglyceride and cholesterol significantly(P＜0.05),groupⅣimproved the activity of SOD significantly(P＜0.05).The content of ALP had no significant difference among groups(P＞0.05).With the increasing of rare earth-chitosan chelate in different levels,trypsin and AMS activity of small intestine chyme in treat group have been improved gradually,but there were no significant among groups(P＞0.05).3.With the addition of rare earth-chitosan chelate increased,the eggs in the test group were higher than the content of lanthanum with the control group,but there were no significant(P＞0.05).The content of cerium in eggs had significant between treat groups with control group(P＜0.05).When the additive of rare earth-chitosan chelate amounted to 0.2%,the content of lanthanum in kidney and thigh had significant between treat groups with control group(P＜0.05),and the content of cerium in thigh had significant between treat groups with control group(P＜0.05).However,the dose of rare earth-chitosan chelate addition in the test were less than lethal dose,only a little of lanthanum and cerium were residued in eggs and tissue after added rare earth-chitosan chelate.As we can see from this study,the results suggested that rare earth-chitosan chelate could activate the activity of digestive enzymes in small intestine.It could promote absorption and utilization of nutrient substance,which increased the production of laying hens.Rare earth-chitosan chelate could reduce the content of cholest in eggs and blood by effecting hepatoenteral circulation.Few of lanthanum and cerium persistence in eggs or tissue,there were no negative influence on laying hens' health.