Investigating The Effect Of Silk Fibroin Powder(SFP)on Laying Performance,Egg Quality And Serum Biochemical Parameter Of Laying Hens

Silk fibroin powder(SFP)is derived from by-products of silk reeling industry,such as low-quality cocoons and waste silk.It contains 18 amino acids and is a lowprice,high-quality natural protein resource to be utilized and developed.The objective of this research is to evaluate the effect of silk fibroin powder(SFP)as a dietary protein source on hens’ productivity,egg quality,serum biochemical parameter and antioxidant capacity.Two hundred and sixteen Hy-Line brown laying hens(30-week-old)were randomly divided into 4 groups with 6 replicates per group,9 hens per replicate.The experiment lasted for 8 weeks.Hens in control group were fed with a basal diet,and experimental groups were fed with basal diet and additional 1%,2%and 4%SFP for group G1,G2 and G3 respectively.The results indicate that:1.SFP had no effect on laying performance and egg quality,while considerably reduce the contents of triglyceride and LDL-C in egg yolkSFP supplementation had no significant effect on performance of laying hens,such as daily feed intake,feed conversion rate,abnormal eggs rate and average egg weight.The productivity of G1(1%SFP)group was the highest(97.22%),while other groups were dramatically lower than control group(P<0.05),the laying rate is significantly decreased in G2(2%SFP),however,adding SFP still can maintain high laying rate.Egg quality including albumen height,eggshell thickness,egg strength and Haugh unit was not impacted when fed with different amount of SFP(P>0.05).The contents of triglyceride and LDL-C in egg yolk were sharply decreased after adding SFP(P<0.05),2%SFP group yielded the lowest contents of triglyceride and LDL-C in egg yolk.2.SFP had no impact on physiological metabolism of laying hensThere was no significant effect on serum protein metabolism and lipid metabolism indicators for hens fed with SFP.The serum antioxidant activity was improved when 1%SFP was added,with no significant different(P>0.05).The activities of total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px)of G1 were the highest,while the content of malondialdehyde(MDA)in G1 group was lower compared with the control group.3.SFP could increase antioxidant capacity in liver and ovary of laying hensMDA concentration in liver and ovary was expressively decreased after 1%SFP supplementation by 18.26%and 19.40%respectively.The GSH-Px activity in ovary of laying hens with 1%SFP was the highest;the activities of T-SOD in liver and ovary were the highest when 2%SFP was supplied,increased 26.02%and 14.30%respectively,the difference is significant(P<0.05).4.SFP had no effect on morphology of liver,ovary and intestinalH&E staining results of liver,ovary and intestinal tissue further proved that,the addition of silk fibroin protein powder had no effect on the morphology of vital organs and oxidative damage of liver and ovary compared with the control group.Supplementation of SFP has not caused any damage on liver,ovary and intestinal tissue.In conclusion,silk fibroin powder(SFP)supplementation has no significant effects on laying performance,blood metabolic indexes and serum antioxidant capacity of laying hens,however,it can dramatically decrease the content of egg yolk triglycerides and LDL-C.What’s more,adding SFP can improve the antioxidant capacity of liver and ovary.