Multi-omics analysis reveals the molecular regulatory network underlying the prevention of Lactiplantibacillus plantarum against LPS-induced salpingitis in laying hens

Background Salpingitis is one of the common diseases in laying hen production, which greatly decreases the economic outcome of laying hen farming. Lactiplantibacillus plantarum was effective in preventing local or systemic inflammation, however rare studies were reported on its prevention against salpingitis. This study aimed to investigate the preventive molecular regulatory network of microencapsulated Lactiplantibacillus plantarum(MLP) against salpingitis through multi-omics analysis, including microbiome, transcriptome and metabolome analyses.Results The results revealed that supplementation of MLP in diet significantly alleviated the inflammation and atrophy of uterus caused by lipopolysaccharide(LPS) in hens(P < 0.05). The concentrations of plasma IL-2 and IL-10 in hens of MLP-LPS group were higher than those in hens of LPS-stimulation group(CN-LPS group)(P < 0.05). The expression levels of TLR2, MYD88, NF-κB, COX2, and TNF-α were significantly decreased in the hens fed diet supplemented with MLP and suffered with LPS stimulation(MLP-LPS group) compared with those in the hens of CN-LPS group(P < 0.05). Differentially expressed genes(DEGs) induced by MLP were involved in inflammation, reproduction, and calcium ion transport. At the genus level, the MLP supplementation significantly increased the abundance of Phascolarctobacterium, whereas decreased the abundance of Candidatus_Saccharimonas in LPS challenged hens(P < 0.05). The metabolites altered by dietary supplementation with MLP were mainly involved in galactose, uronic acid, histidine, pyruvate and primary bile acid metabolism. Dietary supplementation with MLP inversely regulates LPSinduced differential metabolites such as Lyso PA(24:0/0:0)(P < 0.05).Conclusions In summary, dietary supplementation with microencapsulated Lactiplantibacillus plantarum prevented salpingitis by modulating the abundances of Candidatus_Saccharimonas, Phascolarctobacterium, Ruminococcus_torques_group and Eubacterium_hallii_group while downregulating the levels of plasma metabolites, p-tolyl sulfate, o-cresol and N-acetylhistamine and upregulating S-lactoylglutathione, simultaneously increasing the expressions of CPNE4, CNTN3 and ACAN genes in the uterus, and ultimately inhibiting oviducal inflammation.

Prevotella and succinate treatments altered gut microbiota,increased laying performance,and suppressed hepatic lipid accumulation in laying hens

Background This work aimed to investigate the potential benefits of administering Prevotella and its primary metabolite succinate on performance,hepatic lipid accumulation and gut microbiota in laying hens.Results One hundred and fifty 58-week-old Hyline Brown laying hens,with laying rate below 80%and plasma triglyceride(TG)exceeding 5 mmol/L,were used in this study.The hens were randomly allocated into 5 groups and subjected to one of the following treatments:fed with a basal diet(negative control,NC),oral gavage of 3 mL/hen saline every other day(positive control,PC),gavage of 3 mL/hen Prevotella melaninogenica(10^(7)CFU/mL,PM)or 3 mL/hen Prevotella copri(10^(7)CFU/mL,P.copri)every other day,and basal diet supplemented with 0.25%sodium succinate(Succinate).The results showed that PM and P.copri treatments significantly improved laying rate compared to the PC(P<0.05).The amount of lipid droplet was notably decreased by PM,P.copri,and Succinate treatments at week 4 and decreased by P.copri at week 8(P<0.05).Correspondingly,the plasma TG level in Succinate group was lower than that of PC(P<0.05).Hepatic TG content,however,was not significantly influenced at week 4 and 8(P>0.05).PM treatment increased(P<0.05)the mRNA levels of genes PGC-1βand APB-5B at week 4,and ACC and CPT-1 at week 8.The results indicated enhanced antioxidant activities at week 8,as evidenced by reduced hepatic malondialdehyde(MDA)level and improved antioxidant enzymes activities in PM and Succinate groups(P<0.05).Supplementing with Prevotella or succinate can alter the cecal microbiota.Specifically,the abundance of Prevotella in the Succinate group was significantly higher than that in the other 4 groups at the family and genus levels(P<0.05).Conclusions Oral intake of Prevotella and dietary supplementation of succinate can ameliorate lipid metabolism of laying hens.The beneficial effect of Prevotella is consistent across different species.The finding highlights that succinate,the primary metabolite of Prevotella,represents a more feasible feed additive for alleviating fatty liver in laying hens.

Rosemary extract improves egg quality by altering gut barrier function,intestinal microbiota and oviductal gene expressions in late-phase laying hens

Background Rosemary extract(RE)has been reported to exert antioxidant property.However,the application of RE in late-phase laying hens on egg quality,intestinal barrier and microbiota,and oviductal function has not been systematically studied.This study was investigated to detect the potential effects of RE on performance,egg quality,serum parameters,intestinal heath,cecal microbiota and metabolism,and oviductal gene expressions in late-phase laying hens.A total of 21065-week-old“Jing Tint 6”laying hens were randomly allocated into five treatments with six replicates and seven birds per replicate and fed basal diet(CON)or basal diet supplemented with chlortetracycline at 50 mg/kg(CTC)or RE at 50 mg/kg(RE50),100 mg/kg(RE100),and 200 mg/kg(RE200).Results Our results showed that RE200 improved(P<0.05)Haugh unit and n-6/n-3 of egg yolk,serum superoxide dismutase(SOD)compared with CON.No significant differences were observed for Haugh unit and n-6/n-3 of egg yolk among CTC,RE50,RE100 and RE200 groups.Compared with CTC and RE50 groups,RE200 increased serum SOD activity on d 28 and 56.Compared with CON,RE supplementation decreased(P<0.05)total cholesterol(TC)level.CTC,RE100 and RE200 decreased(P<0.05)serum interleukin-6(IL-6)content compared with CON.CTC and RE200 increased jejunal m RNA expression of ZO-1 and Occludin compared with CON.The biomarkers of cecal microbiota and metabolite induced by RE 200,including Firmicutes,Eisenbergiella,Paraprevotella,Papillibacter,and butyrate,were closely associated with Haugh unit,n-6/n-3,SOD,IL-6,and TC.PICRUSt2 analysis indicated that RE altered carbohydrate and amino acid metabolism of cecal microbiota and increased butyrate synthesizing enzymes,including 3-oxoacid Co A-transferase and butyrate-acetoacetate Co A-transferase.Moreover,transcriptomic analysis revealed that RE200 improved gene expressions and functional pathways related to immunity and albumen formation in the oviductal magnum.Conclusions Dietary supplementation with 200 mg/kg RE could increase egg quality of late-phase laying hens via modulating intestinal barrier,cecal microbiota and metabolism,and oviductal function.Overall,RE could be used as a promising feed additive to improve egg quality of laying hens at late stage of production.

Dietary supplementation of Macleaya cordata extract and Bacillus in combination improve laying performance by regulating reproductive hormones,intestinal microbiota and barrier function of laying hens

Background:This study aimed to investigate whether the combination of Macleaya cordata extract(MCE)and Bacil-lus could improve the laying performance and health of laying hens better.Methods:A total of 36029-week-old Jingbai laying hens were randomly divided into 4 treatments:control group(basal diet),MCE group(basal diet+MCE),Probiotics Bacillus Compound(PBC)group(basal diet+compound Bacil-lus),MCE+PBC group(basal diet+MCE+compound Bacillus).The feeding experiment lasted for 42 d.Results:The results showed that the laying rate and the average daily egg mass in the MCE+PBC group were significantly higher than those in the control group(P<0.05)and better than the MCE and PBC group.Combina-tion of MCE and Bacillus significantly increased the content of follicle-stimulating hormone(FSH)in the serum and up-regulated the expression of related hormone receptor gene(estrogen receptor-β,FSHR and luteinizing hormone/choriogonadotropin receptor)in the ovary of laying hens(P<0.05).In the MCE+PBC group,the mRNA expressions of zonula occluden-1,Occludin and mucin-2 in jejunum was increased and the intestinal epithelial barrier detected by transmission electron microscopy was enhanced compared with the control group(P<0.05).In addition,compared with the control group,combination of MCE and Bacillus significantly increased the total antioxidant capacity and catalase activity(P<0.05),and down-regulated the mRNA expressions of inflammation-related genes(interleukin-1βand tumor necrosis factor-α)as well as apoptosis-related genes(Caspase 3,Caspase 8 and P53)(P<0.05).The concen-tration of acetic acid and butyric acid in the cecum content of laying hens in the MCE+PBC group was significantly increased compared with the control group(P<0.05).Conclusions:Collectively,dietary supplementation of 600μg/kg MCE and 5×108 CFU/kg compound Bacillus can improve laying performance by improving microbiota to enhance antioxidant capacity and intestinal barrier,regulate reproductive hormones and the concentration of cecal short-chain fatty acids of laying hens,and the combined effect of MCE and Bacillus is better than that of single supplementation.

Chronic heat stress induces renal fibrosis and mitochondrial dysfunction in laying hens

Background Heat stress in laying hens negatively affects egg production and shell quality by disrupting the homeo-stasis of plasma calcium and phosphorus levels.Although the kidney plays an important role in calcium and phos-phorus homeostasis,evidence regarding the effect of heat stress on renal injury in laying hens is yet to be elucidated.Therefore,the aim of this study was to evaluate the effects of chronic heat stress on renal damage in hens during laying periods.Methods A total of 16 white-leghorn laying hens(32 weeks old)were randomly assigned to two groups(n=8).One group was exposed to chronic heat stress(33°C for 4 weeks),whereas the other group was maintained at 24°C.Results Chronic heat exposure significantly increased plasma creatinine and decreased plasma albumin levels(P<0.05).Heat exposure also increased renal fibrosis and the transcription levels of fibrosis-related genes(COLA1A1,αSMA,and TGF-β)in the kidney.These results suggest that renal failure and fibrosis were induced by chronic heat exposure in laying hens.In addition,chronic heat exposure decreased ATP levels and mitochondrial DNA copy number(mtDNA-CN)in renal tissue,suggesting that renal mitochondrial dysfunction occurs under conditions of heat stress.Damaged mitochondria leak mtDNAs into the cytosol and mtDNA leakage may activate the cyclic GMP-AMP synthase(cGAS)stimulator of interferon genes(STING)signaling pathway.Our results showed that chronic heat exposure activated the cGAS-STING pathway as indicated by increased expression of MDA5,STING,IRF7,MAVS,and NF-κB levels.Furthermore,the expression of pro-inflammatory cytokines(IL-12)and chemokines(CCL4 and CCL20)was upregulated in heat-stressed hens.Conclusions These results suggest that chronic heat exposure induces renal fibrosis and mitochondrial damage in laying hens.Mitochondrial damage by heat stress may activate the mtDNA-cGAS-STING signaling and cause subse-quent inflammation,which contributes to the progression of renal fibrosis and dysfunction.

Adjusting phosphate feeding regimen according to daily rhythm increases eggshell quality via enhancing medullary bone remodeling in laying hens

Background Body phosphorus metabolism exhibits a circadian rhythm over the 24-h daily cycle.The egg laying behavior makes laying hens a very special model for investigating phosphorus circadian rhythms.There is lack of information about the impact of adjusting phosphate feeding regimen according to daily rhythm on the phosphorus homeostasis and bone remodeling of laying hens.Methods and results Two experiments were conducted.In Exp.1,Hy-Line Brown laying hens(n=45)were sampled according the oviposition cycle(at 0,6,12,and 18 h post-oviposition,and at the next oviposition,respectively;n=9 at each time point).Diurnal rhythms of body calcium/phosphorus ingestions and excretions,serum calcium/phosphorus levels,oviduct uterus calcium transporter expressions,and medullary bone(MB)remodeling were illustrated.In Exp.2,two diets with different phosphorus levels(0.32%and 0.14%non-phytate phosphorus(NPP),respectively)were alternately presented to the laying hens.Briefly,four phosphorus feeding regimens in total(each included 6 replicates of 5 hens):(1)fed 0.32%NPP at both 09:00 and 17:00;(2)fed 0.32%NPP at 09:00 and 0.14%NPP at 17:00;(3)fed 0.14%NPP at 09:00 and 0.32%NPP at 17:00;(4)fed 0.14%NPP at both 09:00 and 17:00.As a result,the regimen fed 0.14%NPP at 09:00 and 0.32%NPP at 17:00,which was designed to strengthen intrinsic phosphate circadian rhythms according to the findings in Exp.1,enhanced(P<0.05)MB remodeling(indicated by histological images,serum markers and bone mineralization gene expressions),elevated(P<0.05)oviduct uterus calcium transportation(indicated by transient receptor potential vanilloid 6 protein expression),and subsequently increased(P<0.05)eggshell thickness,eggshell strength,egg specific gravity and eggshell index in laying hens.Conclusions These results underscore the importance of manipulating the sequence of daily phosphorus ingestion,instead of simply controlling dietary phosphate concentrations,in modifying the bone remodeling process.Body phosphorus rhythms will need to be maintained during the daily eggshell calcification cycle.

Effects of Desmodium uncinatum Leaf Meal in the Diet on Lohmann Brown Hens’ Laying Performance and Eggs Quality

A cheap, safe and available alternative protein source to soybean is a huge priority for the developing world. This study is aimed at evaluating the effects of Desmodium uncinatum leaf meal incorporation levels in the diet on Lohmann Brown hens’ laying performances. For this purpose, 60 Lohmann Brown hens aged 33 weeks with an average weight of 1.78 kg were randomly assigned to 3 treatment groups of 20 birds each with 4 replicates. The experimental treatments consisted of DULM 0, DULM5, and DULM10 containing 0, 5 and 10 kg of D. uncinatum leaf meal (DULM) per 100 kg of feed respectively. The results reveal that except for the weights of hens, laying performances were significantly affected (p < 0.05) by DULM in the diet. Daily feed intake was lower with 10% incorporation of DULM in the diet as compared to a diet with 5% DULM which recorded the highest value for this parameter. Moreover, the highest value for the egg weight, egg mass, yolk index, albumen index and egg production were recorded with diet DULM5. On the other hand, the diet with 10% of DULM (DULM10) recorded the highest relative shell weight, feed conversion ratio and egg price. Nevertheless, the mortality rate found in this study was 0% for all treatments confirming the good quality of DULM as protein feedstuff for layer. It was concluded that incorporation levels of D. uncinatum leaves at 5% in the diet improved the laying performances of Lohmann Brown hens.

Dietary oregano essential oil supplementation improves intestinal functions and alters gut microbiota in latephase laying hens

Background:Dietary essential oil(EO)supplementation can exert favorable effects on gut health in broilers.However,it is unknown whether EO could improve intestinal functions,consequently beneficial for egg performance and quality in late-phase laying hens.This study was aimed to investigate the potential effects of EO on production performance,egg quality,intestinal health and ileal microbiota of hens in the late phase of production.A total of 28860-week-old Hy-line Brown laying hens were randomly divided into 4 groups and fed a basal diet(control)or basal diets supplemented with oregano EO at 100,200 and 400 mg/kg(EO100,EO200 and EO400).Results:Dietary EO supplementation resulted in a quadratic decrease(P<0.05)in feed conversion ratio with lower(P<0.05)feed conversion ratio in EO200 group than the control during weeks 9–12 and 1–12 of the trial.Compared to the control,EO addition resulted in higher(P<0.05)eggshell thickness at the end of week.4,8 and 12 and higher(P<0.05)chymotrypsin activity.There was a quadratic elevation(P<0.05)in ileal chymotrypsin and lipase activity,along with a linear increase in villus height to crypt depth ratio.Quadratic declines(P<0.05)in mRNA expression of IL-1β,TNF-α,IFN-γ and TLR-4,concurrent with a linear and quadratic increase(P<0.05)in ZO-1 expression were identified in the ileum with EO addition.These favorable effects were maximized at medium dosage(200 mg/kg)of EO addition and intestinal microbial composition in the control and EO200 groups were assessed.Dietary EO addition increased(P<0.05)the abundances of Burkholderiales,Actinobacteria,Bifidobacteriales,Enterococcaceae and Bacillaceae,whereas decreased Shigella abundance in the ileum.Conclusions:Dietary EO addition could enhance digestive enzyme activity,improve gut morphology,epithelial barrier functions and modulate mucosal immune status by altering microbial composition,thus favoring feed efficiency and eggshell quality of late-phase laying hens.

Soya saponin improves egg-laying performance and immune function of laying hens

Background:Soya saponin(SS),an active compound in soybean meals,has been widely studied in the medical field.However,it was considered as an anti-nutritional factor in poultry diets.The objective of this experiment was to measure the effects of dietary SS using three dietary treatments on egg-laying performance and immune function of laying hens.Birds were fed a low soybean meal basal diet(CON),a low-SS diet(50 SS)containing 50mg/kg SS,or a high-SS diet(500 SS)containing 500 mg/kg SS for 10 weeks.At the end of the 5th and 10th week of the trial,samples were collected for analysis.Results:Results showed that with 50 mg/kg SS supplementation,the egg production rate,feed conversion ratio(FCR),and eggshell quality tended to be improved.Serum follicle stimulating hormone(FSH)and Interleukin-4(IL-4)levels were also elevated as well as the peripheral blood LPS stimulation index,the proportion of B lymphocytes,and antibody titer of bovine serum albumin(BSA).We also found that mRNA levels of follicle stimulating hormone receptor(FSHR)in ovarian,nuclear transcription factor kappa B(NF-κB),Transforming growth factor(TGF-β)and interferonγ(IFN-γ)in spleen were up-regulated at the end of the trial.Additionally,dietary 50 mg/kg SS improved the ileal flora via up-regulating the relative abundance of Lactobacillus,Romboutsia and Lactobacillus delbrueckii.Although the immune related indicators were improved with 500 mg/kg SS supplemented,it seemed to have a negative influence on the laying-performance.Specifically,serum alanine aminotransferase(ALT),alkaline phosphatase(ALP),and the ratio of IFN-γto IL-4 were increased in the 500 SS group at the end of the trial.The m RNA levels of gonadotropin releasing hormone 1(GnRH1)in Hypothalamus,the estrogen related receptor(ERR)in ovaries were downregulated as well as the egg production rate during the trial with 500 mg/kg SS supplemented.Conclusions:The egg production performance was improved by dietary supplemented with 50 mg/kg SS via increasing ovarian FSHR transcription level and serum estrogen level.A beneficial shift in intestinal microflora was recorded,and the immune function of laying hens was also improved with 50 mg/kg SS supplementation.Surprisingly,the long-term supplementation of 500 mg/kg SS exerted a negative impact on the laying performance and physiological functions of the liver of laying hens.

Dietary betaine activates hepatic VTGⅡexpression in laying hens associated with hypomethylation of GR gene promoter and enhanced GR expression

Background: Vitellogenin(VTG) is a precursor of egg yolk proteins synthesized within the liver of oviparous vertebrates. Betaine is an important methyl donor that is reported to improve egg production of laying hens with an unclear mechanism. In the present study, we fed betaine-supplemented diet(0.5%) to laying hens for 4 wk and investigated its effect on VTGII expression in the liver.Results: Betaine did not affect chicken weight, but significantly(P < 0.05) increased egg laying rate accompanied with a significant(P < 0.05) increase in hepatic concentration and plasma level of VTGI. Plasma estrogen level did not change,but the hepatic expression of estrogen receptor α(ERα) mR NA was significantly(P < 0.05) up-regulated. Betaine did not affect the protein content of ERα, but significantly(P < 0.05) increased hepatic expression of glucocorticoid receptor(GR)at both mR NA and protein levels. Also, ERα/GR interaction tended to be enhanced in the liver nuclear lysates of betainesupplemented hens as determined by co-immunoprecipitation. Furthermore, dietary betaine supplementation significantly increased(P < 0.05) the hepatic expression of methyl-transfer enzymes, such as BHMT, GNMT, and DNMT1,which was associated with higher SAM/SAH ratio and hypomethylation of GR promoter regions.Conclusions: Betaine activates hepatic VTGII expression in association with modified DNA methylation of GR gene promoter, GR expression and ERα/GR interaction. Activation of hepatic VTGII expression may contribute, at least partly, to improved egg production in betaine-supplemented hens.

Ascorbic acid synthesis and transportation capacity in old laying hens and the effects of dietary supplementation with ascorbic acid

Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P < 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P < 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P < 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P < 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.

Effect of Supplemental Oregano Essential Oils in Diets on Production Performance and Relatively Intestinal Parameters of Laying Hens

This study was designed to investigate the effects of dietary oregano essential oils on 150 30-week-old Hy-Line Layers’ productive performance, egg quality characteristics, cecal microbiota, digestive enzyme activities, mucosa structure of the duodenum and jejunum and glucose and small peptides transporters expression in the duodenum and jejunum. All hens were allocated into one of five different groups: negative control (NC;basal diet only), antibiotics control (CS;basal diet plus 100 mg/kg of 10% colistin sulfate) and treatments I, II, and III (basal diet supplemented with 50, 100 and 150 mg/kg oregano essential oils, respectively). The results showed that the laying rate, average egg weight, feed conversion ratio and the activities of amylase and trypsin were significantly improved by a diet supplemented with 100 mg/kg oregano essential oils (P 0.05), significantly increased duodenum villus-height-to-crypt-depth ratios (P 0.05).

Application of Several Additives Instead of Antibiotics in the Production of Laying Hens

[Objective] The test was conducted to study the effect of three different additives instead of antibiotics in the production of laying hens. [Method]Basal diets in four test groups were added with 0. 015% oxytetracycline,0. 01% microecological preparation,0. 2% fulvic acid,and 0. 1% Chinese herbal medicine extract respectively,and laying hens in control group were fed with basal diets. Effect of four different additives on performance and egg quality were studied under the temperature of 28. 6℃. [Result]The average egg-laying rate and feed-egg ratio in groups 2,3 and 4 were significantly better than those in control group and group 1( P < 0. 05). The contents of fat and cholesterol in eggs in groups 2,3 and 4 were lower than those in control group and group 1. And the fat content of eggs in group 4 was 13. 42% lower than that in control group,the difference was significant( P < 0. 05). The protein contents in groups 2,3 and 4 were significantly higher than those in control group and group 1( P < 0. 05). [Conclusion] Microecological preparation,fulvic acid and Chinese herbal medicine extract could replace antibiotics to be applied in the production of laying hens.

Effects of Exposure to Lead and Cadmium on the Oxidative Damage of Livers in Laying Hens

[Objective] To detect the effects of exposure to lead and cadmium on the oxidative damage of livers in laying hens. [Methods] One hundred and twenty 40-week-old Hyline brown hens were randomly divided into four groups. 100 mg / L Pb and / or 50 mg / L Cd was added into the drinking water for eight weeks. [Results] Compared with control group,AST and ALT activities in Pb group enhanced; but there were no significant differences. AST and ALT activities in Cd group and( Pb + Cd) group significantly or extremely significantly increased( P < 0. 05 or P < 0. 01). SOD activity,GSH- Px activity and GSH content in( Pb + Cd) group,Cd group and Pb group were significantly or extremely significantly lower than those in control group( P <0. 05 or P <0. 01). Among them,( Pb + Cd) group showed the greatest reduction( P <0. 01). MDA contents in the three groups were significantly higher than that of control group; and( Pb +Cd) group was significantly higher than Pb group and Cd group. Cu,Fe and Zn contents in three groups were higher than those in control group in different degrees( P <0. 05 or P <0. 01). Se contents in Cd group and( Pb + Cd) group were significantly lower than that in control group( P <0. 01). Residue contents in livers in Pb group and Cd group were significantly greater than that in control group; while residue content in( Pb + Cd) group was significantly higher than those in Pb group and Cd group. Ultrastructure showed that there were symptoms of mitochondrial swelling and fractured cristae in liver cells of laying hens after the exposure to Cd and Pb. In( Pb + Cd) group,these symptoms were even greater. [Conclusion] Oxidative damage and disturbance of trace element metabolism were one of the mechanisms for hepatotocity in laying hens induced by Pb and Cd,and synergistic effect lied in the coadministration.

Mechanism of the Effect of Bacillus coagulans on Production Performance of Laying Hens in Late Laying Period

[Objective]The paper was to investigate the mechanism of Bacillus coagulans preparation in improving production performance of laying hens in late period of laying.[Method]A total of 648 individuals of"Jingfen 1"laying hens(66 weeks of age)in late period of laying were randomly divided into four groups,six replicates each group,and each group had 27 individuals of laying hens.The laying hens in control group were fed with basal diet,and those in experimental groupsⅠ,Ⅱ and Ⅲ were fed with the basal diets added with 3.33×10^6,1×10^7,3.33×10^7 CFU/g B.coagulans,respectively.The pretrial lasted one week,and the formal test lasted eight weeks.[Result]Compared with the control group,the laying rate in group Ⅰ increased significantly,and the feed-gain ratio in experimental group Ⅱ decreased noticeably while the spleen index increased remarkably;the alkaline phosphatase activities and blood calcium content in experimental groups Ⅰ,Ⅱ and Ⅲ increased significantly(P<0.05),while the triglyceride content decreased remarkably(P<0.05);the urea content in experimental groups Ⅰ and Ⅱ decreased obviously(P<0.05).Adding B.coagulans significantly increased the specific activity of amylase,lipase and protease in various intestinal mucosa of small intestine(P<0.05);adding B.coagulans significantly increased the content of follicle-stimulating hormone(FSH)and estradiol(E2),and significantly increased the mRNA expression of follicle stimulating hormone receptor gene(FSHR).[Conclusion]B.coagulans preparation could significantly improve the production performance of laying hens in late period of laying;appropriately enhance the immune capacity of laying hens;improve the serum biochemical indicators;increase the activity of digestive enzymes in the small intestine;and promote the release of gonadal hormone and the mRNA expression of FSHR gene in the ovary.

Effect of Quercetin on Egg Quality and Components in Laying Hens of Different Weeks

This trial was conducted to evaluate the effect of quercetin on egg quality and components in laying hens of different weeks. A total of 240 healthy Hessian laying hens at 29, 39-week-old with similar body weight and laying rate were randomly divided into four groups with six replicates of 10 each replicate, respectively. The treatments were fed with basal diet supplemented with 0, 0.2, 0.4 and 0.6 g · kg^(-1) quercetin for 8 weeks. The results showed that compared with the control, broken or soft shell rate significantly decreased at 0.2 and 0.4 g · kg^(-1) quercetin and eggshell thickness significantly increased at 0.4 g · kg^(-1) quercetin(P<0.01) in laying hens at 39-47 weeks old; yolk protein significantly decreased at 0.6 g · kg^(-1) quercetin(P<0.05) in laying hens at 29-37 weeks old; while yolk protein significantly increased at three quercetin treatments in laying hens at 39-47 weeks old; yolk cholesterol significantly decreased by quercetin in laying hens at 29-37 weeks old(P<0.05); yolk total phospholipids significantly increased at 0.4 and 0.6 g · kg^(-1) quercetin(P<0.01) and yolk cholesterol significantly decreased at 0.6 g · kg^(-1) quercetin(P<0.05) in laying hens at 39-47 weeks old. In a word, quercetin affected egg quality and components to some extents in laying hens of different weeks, the older the hens became, the better improvement they would be. The optimum level of quercetin was 0.4 g · kg^(-1) in the basal diet.

The Effect of Different Levels of Sesame Oil on Productive Performance, Egg Yolk and Blood Serum Lipid Profile in Laying Hens

Addition of sesame oil into layer diets has been proved to enrich the proportion of polyunsatu-rated fatty acids in animal’s products. In this study, the effects of different levels of sesame oil in the diets on the performance, egg yolk and blood serum lipid profile of Isa Brown laying hens were investigated. A total of 96 layers were assigned into 4 groups to receive either 1 of 4 different diets contained 0.0%, 1.5%, 3.0% and 4.5% sesame oil, respectively. Sample of 12 eggs obtained from each groups were assessed for egg quality. The egg yolk fatty acid profile was determined with gas chromatography. Results revealed that the higher levels of sesame oil in the diet decreased egg production, egg weight, and egg yolk color except feed conversion ratio. In addition, supplementation of sesame oil increased the flow index of the eggs and the Haugh unite. The egg yolk lipid profile was not significantly different in the sesame oil fed groups, whereas, compare to control, it decreased the level of cholesterol. The blood serum lipid profile decreased in the sesame oil groups compare to control group. Meanwhile, monoacildigliserol also decreased in the sesame addition groups. In parallel with increasing levels of sesame oil, monounsaturated fatty acid (oleic acid) in the egg yolks significantly increased compared to the control (37.00%, 42.89%, 42.20% and 43.48%, respectively). It can be implied that sesame oil supplementation into the laying hens diet is necessary to produce monounsaturated fatty acid (MUFA) enriched eggs.

Influence of Varying Crude Protein Levels and Balanced Amino Acids on the Performance and Haematological Characteristics of Laying Hens at the Second Phase of Production

Varying levels of dietary crude proteins and balanced amino acids were fed to layers for a period of eight weeks starting from the twenty-sixth week of age of birds and six weeks into egg production. Effects on performance and haematological characteristics were investigated at this second phase of production. Sixty Black Nera hens were randomly allotted into four (4) dietary treatments, containing the following levels of crude protein 14%, 15%, 16%, 17% and the metabolizable energy was iso-caloric for each treatment. The results showed that there were no significant differences (P > 0.05) observed for lymphocyte, Haemoglobin (Hb), Packed Cell Volume (PCV), Red Blood Cell (RBC) and White Blood Cell (WBC), these haematological parameters were within the range for healthy birds. Thus crude protein level of 14% can be used in diets of layers at the second phase of production provided that adequate amino acids are given, without adverse effect on egg laying, feed intake and measured blood parameters.

Effects of Xylooligosaccharide(XOS)and Probiotics(PRO)on Production Performance,Egg Quality and Intestinal Short-chain Fatty Acids of Laying Hens in Late Laying Period

[Objective]The paper was to study the effects of xylooligosaccharide(XOS)and probiotics(PRO)and their interaction on the production performance,egg quality and intestinal short-chain fatty acids of laying hens in late laying period.[Method]A total of 36074-week-old Romain brown laying hens were randomly divided into four groups,six replicates each group and 15 chickens each replicate.The trial lasted 63 d.The laying hens in control group(CON)were fed with basal diet,and those in experimental groups were fed with the basal diets adding with 150 mg/kg XOS(XOS group),100 mg/kg probiotics(PRO group),150 mg/kg XOS+100 mg/kg probiotics(XOS-PRO group).[Result]Compared with the control group,the laying rate,daily egg production,yolk ratio,colonic acetic acid and caecal propionic acid in XOS group increased significantly(P<0.05),and the feed gain ratio decreased remarkably(P<0.05).PRO had no significant effect on the production performance and egg quality of laying hens in late laying period(P>0.05),but significantly increased colonic acetic acid(P<0.05).XOS and PRO had no interaction effect on the production performance,egg quality and intestinal short-chain fatty acids of laying hens in late laying period(P<0.05).[Conclusion]Adding XOS to the diet of laying hens in late laying period could increase the content of short-chain fatty acids in the hindgut of laying hens,and effectively improve the production performance and egg quality of laying hens in late laying period.Adding PRO to the diet did not significantly improve the production performance and egg quality of laying hens,and there was no interaction effect between XOS and PRO.

Effects of dietary phosphorous supplementation on laying performance,egg quality,bone health and immune responses of laying hens challenged with Escherichia coli lipopolysaccharide

Background: Phosphorus is an essential nutrient to maintain poultry health and performance. The objective of this study was to evaluate the effect of dietary phosphorus levels on egg production, egg quality, bone health, immune responses of laying hens challenged with Escherichia coli lipopolysaccharide.Methods: Three hundred laying hens at 28 wk were randomly divided into 2 dietary treatments with 10 replicates of 15 birds. The wheat-soybean based diets contained either 0.12% or 0.4% non-phytate phosphorus(NPP). At 32 wk of age, all the birds of each dietary treatment were injected into the abdomen with 1.5 mg/kg body weight(BW) of either LPS or saline once a day at 24-h intervals for continuous 9 d. The performance of laying hens was evaluated for 9 d. The eggs after the fifth injection were collected to value the egg quality. Three hours after the first injection, blood was collected to measure serum metabolite and immune response associated parameters.Three hours after the fifth injection, the hens were euthanized to obtain tibia, cecal tonsils and jejunum.Results: Compared with saline-injected hens, LPS-injected hens had lower feed intake and egg production(P < 0.05).Eggshell thickness, strength, albumin height and Haugh unit were significantly increased in LPS-injected hens compared with saline-injected hens(P < 0.05). Furthermore, laying hens challenged with LPS had lower villious height/crypt depth ration than those received saline. Serum calcium, phosphorus and SOD activities significantly decreased in the LPS-injected hens compared with the control(P < 0.05). LPS up-regulated expression of IL-1β, IL-6 and IL-10 in cecum, and serum concentration of MDA, IL-1β and IL-6(P < 0.05), whereas 0.40% dietary non-phytate phosphorus supplementation significantly increased(P < 0.05) villi height/crypt depth ratio, decreased(P < 0.05) serum MDA and IFN-γ concentration compared with the 0.12% non-phytate phosphorus group.Conclusion: In summary, this study demonstrates that 0.40% dietary non-phytate phosphorus supplementation significantly increased calcium and phosphorus levels of eggshell, increased villi height/crypt depth ratio, decreased serum MDA and IFN-γ concentration compared with the 0.12% non-phytate phosphorus groups. The results indicate that high level of dietary non-phytate phosphorus exerts a potential effect in alleviating systemic inflammation of LPSchallenged laying hens.