Effects Of Different Oils On Production Performance,Egg Quality And Lipid Metabolism Of Laying Hens

In this study,the effects of different oils supplementation on the performance,egg quality and lipid metabolism of laying hens were compared.And the mechanism was disscussed by analyzing the apparent digestibility of crude fat,intestinal villi and liver cell morphology,lipid metabolism in plasma and liver,anti-oxidation,immunity and other relevant biochemical indexes.Total of 324 520-day-old jingfen No.1 commercial layer chickens with similar egg production were divided into 3 groups with 6 replicates per treatments after a 15 days’ pre-test.Group 1,2 and 3 layers were fed diets containing 2%lard,palm oil or soybean oil respectively.The formal trial lasted for 8 weeks,egg samples were collected on wednesday of week 3,5 and 7,respectively.Metabolic test were conducted at week 8,and 12 layers per treatment were slaughtered for sampling after the formal trial.The results showed as follows:(1)Results of feeding trail showed that the average egg weight of soybean oil group was significantly higher(P<0.05)than that of lard group and palm oil group.The total egg weight was highest(P>0.05)and the feed-to-egg ratio was lowest(P>0.05)at 8 weeks in the soybean oil group.And there were no significant difference among three groups in daily feed intake and egg production rate(P>0.05).(2)Results of egg quality determination showed that,there was no significant difference in egg quality among three groups(P>0.05),but the soybean oil group was better for eggshell strength and thickness,while the lard group was better for yolk color,Hangh Unit and protein height.(3)Results of metabolic test showed that,the apparent metabolic rate of crude fat was highest in the soybean oil group,15.26%higher(P<0.05)than that in the palm oil group,but there was no significant difference(P>0.05)between the soybean oil group and the lard oil group.(4)Results of fat metabolism determination showed that the soybean oil group had the mildest degree of fatty liver,lowest fat content,best lipid metabolism indexes of plasma and liver,highest content of UFA and lowest content of SFA in egg yolk.(5)Results of bone indexes determination showed that the lard group had the highest ALP and IGF-I content in plasma and the difference reached a significant level(P<0.05).In addition,the bone density and mineral salt content were also highest in the lard group(P>0.05).(6)Results of antioxidant indexes determination showed that,all antioxidant indexes in plasma and liver were the best in the palm oil group except SOD content in plasma,but there were no significant difference among three groups(P>0.05).(7)Results of immune indexes determination showed that the palm oil group had better immune indexes,in which the plasma IgG content increased by 43.41%(P<0.05),the IL-6 and TNF-α decreased by 12.40%(P<0.05)and 23.43%(P<0.05)compared with lard group.But there was no significant difference between palm oil and soybean oil group(P>0.05).Our results indicated that,under the conditions of this experiment,among three kinds of oils,soybean oil can improve the average egg weight,body lipid metabolism and fatty acids deposition in eggs.While,lard has beneficial effects on the bone quality and palm oil has beneficial effects on the immune function of laying hens.