The Role Of Microecologics In Enhancing Laying Performance And Egg Quality Of Laying Hens

In a bid to enhance performance and production of high-quality eggs while modulating the physiology of the laying hens to maintain stable animal health and welfare.Nutritional strategies that improve immune response,serum antioxidant capacity,hematology,intestinal morphology and function,egg production and quality,are recommended.Experiment 1:Effect of partial replacement of soybean meal with fermented soybean meal on performance,egg quality,gut morphology,antioxidant and immune response of young laying hens.A total of Hy-line Brown laying hens(18 weeks-old)were randomly assigned to 5 groups of 72 birds each(6 replications of 12 birds each).The dietary group consists of control(basal diet;SBM),and other 4groups which consists of basal diet and FSBM at 2.5%,5.0%,7.5%and 10%inclusion levels respectively.The feeding trial lasted for 12 weeks.Our findings revealed that fermentation improved the nutritional value of fermented soybean meal as evidenced by reduced content of trypsin inhibitor,increased crude protein,amino acids and minerals,in comparison to ordinary soybean meal.The fermented soybean at all inclusion levels enhanced egg production(p<0.05)and feed-egg ratio(p<0.05),albumen quality(albumen height and Haugh unit)(p<0.05),apparent fecal amino acid digestibility(p<0.05),gut morphology(increased villi height,villi width,villi height to crypt depth ratio and decreased crypt depth)(p<0.05),antioxidant capacity(Reduced malondialdehyde and increased catalase,total superoxide dismutase,glutathione peroxidase and total antioxidant capacity)(p<0.05)and immune function(Increased concentrations of Ig G,Ig A,and Ig M;increased levels of TGF-β,TLR2 and reduced levels of IL-1β,TNF-α)(p<0.05)compared to the control group.The 7.5%and 10%inclusion rate significantly(p<0.05)enhanced the physiological response of the birds compared to other levels.Further analysis showed that fermented soybean altered composition of gut microbiota.The aforementioned findings suggest that fermented soybeans could be included in poultry diets at 2.5 or 5.0%level,due to its better nutritional value,anti-inflammatory effect and gut morphology which facilitates better nutrient utilization for increased egg production and egg quality.Experiment 2:Effect of Clostridium butyricum and Brevibacillus strains on egg production,egg quality,immune response and antioxidant function,apparent fecal amino acid digestibility,and jejunal morphology of laying hens.A total of 288 healthy 30-week-old Hy-Line Brown laying hens were arbitrarily assigned to four dietary treatments;basal diet,and basal diet supplemented with 0.02%of C.butyricum zlc-17,C.butyricum lwc-13,or Brevibacillus zlb-z1,for 84 days.Each treatment had 6replicates with 12 birds each.Our findings revealed that dietary C.butyricum and Brevibacillus,respectively exerted a positive impact on laying performance,egg quality and physiological response of the birds(p<0.05).The diets enhance egg production rate,average egg weight,egg mass and feed efficiency,while zero mortality was recorded(p<0.05).Further analysis demonstrated that probiotics improved eggshell quality,Haugh unit,thick albumen content,and albumen height(p<0.05).Also,probiotics enhanced the antioxidant status via increased antioxidant enzymes(p<0.05),and jejunal morphology as evidenced by increased villi surface area(VSA),the ratio of villi height to crypt depth,villi width,and villi height,and a significant reduction in crypt depth(p<0.05).The concentrations of immunoglobulin M and A(Ig M and Ig A)increased significantly in the probiotics group and the same effect was notable for complement proteins(C3)and immune organ(Spleen)(p<0.05).Besides,nutrient absorption and retention were enhanced,as apparent fecal amino acid digestibility of key essential amino acids was substantially improved in the diet-based group(p<0.05).Conclusively,the supplementation of Clostridium butyricum zlc-17 in comparison to Clostridium butyricum lwc-13 and Brevibacillus zlb-z1 strains significantly(p<0.05),promoted the antioxidant status,modulated the intestinal structure,enhanced amino acid digestibility,and regulated the immunity index of the laying hens,which finally improved laying performance and egg quality of the laying hens.Experiment 3:Effect of dietary fructooligosaccharides(FOS)as prebiotics on the performance,egg quality,gut morphology,apparent fecal amino acid digestibility,antioxidant and immune function of laying hens.A total of 216 healthy Hy-Line brown laying hens aged 30 weeks were randomly assigned to one of three dietary treatments:basal diet,basal diet supplemented with 0.3%FOS,or 0.6%FOS.For84 days,each treatment was fed the corresponding experimental diet.According to the findings,dietary supplementation with FOS enhanced laying performance and egg mass while lowering mortality rate(p<0.05).Albumen height,thick albumen content,Haugh unit,and eggshell thickness were also improved by prebiotics(p<0.05).Furthermore,prebiotics boosted antioxidant status by increasing the activity of antioxidant enzymes(p<0.05),improved morphological development of the jejunum as demonstrated by significant increases in villi height,villi width,ratio of villi height to crypt depth,and reduced crypt depth(p<0.05).The prebiotics group showed a considerable increase in immunoglobulin M,G,and A(Ig M,Ig G,and Ig A)levels(p<0.05).,as well as a similar effect on complement protein(C3).Besides,the apparent fecal amino acid digestibility of most essential amino acids was significantly enhanced(p<0.05).Conclusively,fructooligosaccharides at inclusion level of 0.6%efficiently enhanced laying performance and production of high-quality eggs while positively modulating amino acid digestibility,jejunal morphology,antioxidant status,and immune functions of the laying hens.Experiment 4:Effects of Clostridium butyricum(CB)and Fructooligosaccharides(FOS)singly or combined,on performance,egg quality,amino acid digestibility,jejunal morphology,immune function and antioxidant capacity in peak-phase laying hens.A total of 288 Hy-Line Brown laying hens(30 weeks of age)were randomly assigned to 4 dietary groups that included basal diet,basal diet+0.02%of C.butyricum(zlc-17:1×10~9 CFU/g),basal diet+0.6%fructooligosaccharides(FOS),and basal diet+0.02%C.butyricum+0.6%fructooligosaccharides for 12 weeks.Each treatment had 6 replicates with 12 birds each.The results demonstrated that probiotics(PRO),prebiotics(PRE)and synbiotics(SYN)(p<0.05),respectively,exerted a positive effect on the performance and physiological response of the birds.There were significant increases in egg production rate,egg weight,egg mass,daily feed intake,reduced number of damaged eggs and zero mortality rate.Also,feed conversion was improved by PRO(p<0.05).In addition,egg quality assessment showed that;eggshell quality was increased by PRO(p<0.05),and albumen indices(Haugh unit,thick albumen content,and albumen height)were enhanced by PRO,PRE and SYN(p<0.05).Further analysis showed that PRO,PRE and SYN(p<0.05),reduced heterophil to lymphocyte ratio,increased antioxidant enzymes and immunoglobulin concentration.Although spleen index was higher for PRO(p<0.05)group.The significant increase in villi height,villi width,villi height to crypt depth ratio and reduced crypt depth were obvious for PRO,PRE,and SYN(p<0.05).Furthermore,improved nutrient absorption and retention evidenced by increased digestibility of crude protein and amino acids,were notable for PRO,PRE,and SYN(p<0.05)group.Collectively,our findings revealed that dietary CB and FOS alone,or combined,enhanced productive performance,egg quality,amino acid digestibility,jejunal morphology,and physiological response in peak-phase laying hens.Interestingly,synbiotics enhanced albumen quality,villi morphology and digestibility of amino acids compared to other treatments.Our results would provide direction on nutritional strategies for gut enhancers and better physiological response of peak laying hensCollectively,partial replacement of soybean meal with fermented soybean meal,supplementation of prebiotics(FOS),probiotics(CB)and synbiotics(FOS and CB)as feed additives,enhanced the laying performance,egg quality,gut morphology,amino acid digestibility,antioxidant and immune function.The improved positive effects could be adducible to enhanced fermentation effect of probiotics and prebiotics in the gut and increased nutritional value of fermented soybean due to fermentation processing technique.