Effects of different energy levels in low-protein diet on liver lipid metabolism in the late-phase laying hens through the gut-liver axis

Background The energy/protein imbalance in a low-protein diet induces lipid metabolism disorders in late-phase laying hens.Reducing energy levels in the low-protein diet to adjust the energy-to-protein ratio may improve fat deposition,but this also decreases the laying performance of hens.This study investigated the mechanism by which different energy levels in the low-protein diet influences liver lipid metabolism in late-phase laying hens through the enterohepatic axis to guide feed optimization and nutrition strategies.A total of 288 laying hens were randomly allocated to the normal-energy and normal-protein diet group(positive control:CK)or 1 of 3 groups:lowenergy and low-protein diet(LL),normal-energy and low-protein diet(NL),and high-energy and low-protein diet(HL)groups.The energy-to-protein ratios of the CK,LL,NL,and HL diets were 0.67,0.74,0.77,and 0.80,respectively.Results Compared with the CK group,egg quality deteriorated with increasing energy intake in late-phase laying hens fed low-protein diet.Hens fed LL,NL,and HL diets had significantly higher triglyceride,total cholesterol,acetylCo A carboxylase,and fatty acid synthase levels,but significantly lower hepatic lipase levels compared with the CK group.Liver transcriptome sequencing revealed that genes involved in fatty acid beta-oxidation(ACOX1,HADHA,EHHADH,and ACAA1)were downregulated,whereas genes related to fatty acid synthesis(SCD,FASN,and ACACA)were upregulated in LL group compared with the CK group.Comparison of the cecal microbiome showed that in hens fed an LL diet,Lactobacillus and Desulfovibrio were enriched,whereas riboflavin metabolism was suppressed.Cecal metabolites that were most significantly affected by the LL diet included several vitamins,such as riboflavin(vitamin B2),pantethine(vitamin B5 derivative),pyridoxine(vitamin B6),and 4-pyridoxic acid.Conclusion A lipid metabolism disorder due to deficiencies of vitamin B2 and pantethine originating from the metabolism of the cecal microbiome may be the underlying reason for fat accumulation in the liver of late-phase laying hens fed an LL diet.Based on the present study,we propose that targeting vitamin B2 and pantethine(vitamin B5 derivative)might be an effective strategy for improving lipid metabolism in late-phase laying hens fed a low-protein diet.

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.

Coated sodium butyrate ameliorates high‑energy and low‑protein diet induced hepatic dysfunction via modulating mitochondrial dynamics, autophagy and apoptosis in laying hens

Background Fatty liver hemorrhagic syndrome(FLHS),a fatty liver disease in laying hens,poses a grave threat to the layer industry,stemming from its ability to trigger an alarming plummet in egg production and usher in acute mortality among laying hens.Increasing evidence suggests that the onset and progression of fatty liver was closely related to mitochondria dysfunction.Sodium butyrate was demonstrated to modulate hepatic lipid metabolism,alle-viate oxidative stress and improve mitochondrial dysfunction in vitro and mice models.Nevertheless,there is limited existing research on coated sodium butyrate(CSB)to prevent FLHS in laying hens,and whether and how CSB exerts the anti-FLHS effect still needs to be explored.In this experiment,the FLHS model was induced by administering a high-energy low-protein(HELP)diet in laying hens.The objective was to investigate the effects of CSB on alleviating FLHS with a focus on the role of CSB in modulating mitochondrial function.Methods A total of 288 healthy 28-week-old Huafeng laying hens were arbitrarily allocated into 4 groups with 6 replicates each,namely,the CON group(normal diet),HELP group(HELP diet),CH500 group(500 mg/kg CSB added to HELP diet)and CH750 group(750 mg/kg CSB added to HELP diet).The duration of the trial encompassed a period of 10 weeks.Results The result revealed that CSB ameliorated the HELP-induced FLHS by improving hepatic steatosis and patho-logical damage,reducing the gene levels of fatty acid synthesis,and promoting the mRNA levels of key enzymes of fatty acid catabolism.CSB reduced oxidative stress induced by the HELP diet,upregulated the activity of GSH-Px and SOD,and decreased the content of MDA and ROS.CSB also mitigated the HELP diet-induced inflammatory response by blocking TNF-α,IL-1β,and F4/80.In addition,dietary CSB supplementation attenuated HELP-induced activation of the mitochondrial unfolded protein response(UPRmt),mitochondrial damage,and decline of ATPase activity.HELP diet decreased the autophagosome formation,and downregulated LC3B but upregulated p62 protein expression,which CSB administration reversed.CSB reduced HELP-induced apoptosis,as indicated by decreases in the Bax/Bcl-2,Caspase-9,Caspase-3,and Cyt C expression levels.Conclusions Dietary CSB could ameliorate HELP diet-induced hepatic dysfunction via modulating mitochondrial dynamics,autophagy,and apoptosis in laying hens.Consequently,CSB,as a feed additive,exhibited the capacity to prevent FLHS by modulating autophagy and lipid metabolism.

Lactiplantibacillus plantarum FRT4 attenuates high-energy low-protein dietinduced fatty liver hemorrhage syndrome in laying hens through regulating gut-liver axis

Background Fatty liver hemorrhage syndrome(FLHS)becomes one of the most major factors resulting in the laying hen death for caged egg production.This study aimed to investigate the therapeutic effects of Lactiplantibacillus plan-tarum(Lp.plantarum)FRT4 on FLHS model in laying hen with a focus on liver lipid metabolism,and gut microbiota.Results The FLHS model of laying hens was established by feeding a high-energy low-protein(HELP)diet,and the treatment groups were fed a HELP diet supplemented with differential proportions of Lp.plantarum FRT4.The results indicated that Lp.plantarum FRT4 increased laying rate,and reduced the liver lipid accumulation by regulating lipid metabolism(lipid synthesis and transport)and improving the gut microbiota composition.Moreover,Lp.plan-tarum FRT4 regulated the liver glycerophospholipid metabolism.Meanwhile,“gut-liver”axis analysis showed that there was a correlation between gut microbiota and lipid metabolites.Conclusions The results indicated that Lp.plantarum FRT4 improved the laying performance and alleviated FLHS in HELP diet-induced laying hens through regulating“gut-liver”axis.Our findings reveal that glycerophospholipid metabolism could be the underlying mechanism for the anti-FLHS effect of Lp.plantarum FRT4 and for future use of Lp.plantarum FRT4 as an excellent additive for the prevention and mitigation of FLHS in laying hens.

Effect of dietary supplementation with discardednutrient medium of Cordyceps militaris on layingperformance and diversity of intestinal flora in laying hens

The aim of the experiment was to explore the feasibility of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens. 100 g/kg, 200 g/kg, 300 g/kg of discarded nutrient medium of Cordyceps militaris were added to the basal diet of laying hens. The results showed that the optimal addition of discarded nutrient medium of Cordyceps militaris in the diet of laying hens was 10%. According to the results of measuring the conventional indicators of eggs, the weight of eggs produced by laying hens fed with discarded nutrient medium of Cordyceps militaris was higher than that of laying hens fed with ordinary laying hens. The content of interleukin-1(IL-1) in the experimental group was significantly higher than that in the control group, and the concentration of IL-1 increased by 141.5 pg/mL, which indicated that the application of discarded nutrient medium of Cordyceps militaris effectively improved the immunity of laying hens. The high-throughput analysis of the intestinal contents of the two groups of laying hens showed that the microbial population abundance of the intestinal tract of the experimental group was greater than that of control group, and the application of discarded nutrient medium of Cordyceps militaris increased the diversity of bacteria in the intestinal tract of laying hens. In addition, the sensitivity of some pathogenic bacteria in the intestinal tract of chickens to drugs was also increased, thereby reducing the use of antibiotics. The secondary utilization of discarded nutrient medium of Cordyceps militaris has great development and utilization prospects, which provided a scientific reference and basic theoretical basis for the development of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens.

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.

Decreased eggshell strength caused by impairment of uterine calcium transport coincide with higher bone minerals and quality in aged laying hens

Background Deteriorations in eggshell and bone quality are major challenges in aged laying hens.This study compared the differences of eggshell quality,bone parameters and their correlations as well as uterine physiologi-cal characteristics and the bone remodeling processes of hens laying eggs of different eggshell breaking strength to explore the mechanism of eggshell and bone quality reduction and their interaction.A total of 24074-week-old Hy-line Brown laying hens were selected and allocated to a high(HBS,44.83±1.31 N)or low(LBS,24.43±0.57 N)eggshell breaking strength group.Results A decreased thickness,weight and weight ratio of eggshells were observed in the LBS,accompanied with ultrastructural deterioration and total Ca reduction.Bone quality was negatively correlated with eggshell quality,marked with enhanced structures and increased components in the LBS.In the LBS,the mammillary knobs and effective layer grew slowly.At the initiation stage of eggshell calcification,a total of 130 differentially expressed genes(DEGs,122 upregulated and 8 downregulated)were identified in the uterus of hens in the LBS relative to those in the HBS.These DEGs were relevant to apoptosis due to the cellular Ca overload.Higher values of p62 protein level,caspase-8 activity,Bax protein expression and lower values of Bcl protein expression and Bcl/Bax ratio were seen in the LBS.TUNEL assay and hematoxylin-eosin staining showed a significant increase in TUNEL-positive cells and tissue damages in the uterus of the LBS.Although few DEGs were identified at the growth stage,similar uterine tissue damages were also observed in the LBS.The expressions of runt-related transcription factor 2 and osteocal-cin were upregulated in humeri of the LBS.Enlarged diameter and more structural damages of endocortical bones and decreased ash were observed in femurs of the HBS.Conclusion The lower eggshell breaking strength may be attributed to a declined Ca transport due to uterine tissue damages,which could affect eggshell calcification and lead to a weak ultrastructure.Impaired uterine Ca transport may result in reduced femoral bone resorption and increased humeral bone formation to maintain a higher mineral and bone quality in the LBS.

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.

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.

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 Traditional Chinese Herbal Medicines on Blood Ions and Enzymes of Egg-laying Hens Under Heat Stress

[Objective] This study was conducted to investigate the effects of tradi- tional Chinese herbal medicines on blood biochemical indices of egg-laying hens under heat stress and to provide theoretical basis for clinical application of the medicines. [Method] One hundred of 88-day-old ISA-Brown hens were randomly di- vided into five groups. The hens in four groups were administrated with Prescription I herbal medicines, Prescription II herbal medicines, Vc and blank control under ar- tificially simulated heat stress, respectively. The last group was raised under normal temperature condition. Blood samples of the hens were collected on 1, 4, 8 and 10 d later and detected for their biochemical indices. [Result] The blood sodium （Na）, phosphorus （P）, potassium （K） and chlorine （CI） concentrations in hens under heat stress were decreased, while the activities of alanine aminotransferase （ALT）, lactate dehydrogenase （LDH） and creatine kinase （CK） were increased. These indices grad- ually returned to normal levels after the use of traditional Chinese herbal medicines. [Conclusion] The herbal medicines can relieve the adverse effects caused by heat stress to blood biochemical indices via different metabolic pathways of ions and en- zymes.

End of Transportation of Spent Laying Hens： From Idea to Solution

Transportation of spent laying hens causes them severe suffering. HAI-MESHEK （The Israeli Society for the Prevention of Cruelty to Farm Animals） looked for ways to decrease the suffering and finally developed the solution. Spent laying hens are brutally taken out of the cages, and with broken legs and chests pressed into small boxes for transportation to the slaughter-house. Removing all hens from the cages, transportation, waiting in the slaughter-house and slaughtering all hens is a long and hard-suffering time, which may take 8-10 hours. Hai-Meshek conducted a research, aimed at finding more humane methods of transportation. The findings from other countries were very disappointing. Even in countries having high level of animal welfare, about 30% of the hens arrived at the slaughter-house with broken limbs! The conclusion was that even better method, imposed by legislation, would not solve the problem： it is difficult to detect truck drivers violating the rules and the fine is negligible, compared to the savings by the abovementioned cruel method. The only humane solution is by preventing the transportation and slaughtering on farm. Spent laying hens are not edible, so they need not be slaughtered in the slaughter-house. Hai-Meshek initiated and participated in the development and the building of a facility for the humane killing of spent laying hens on farms. The hens aye electrified and die in 1-1.5 seconds. This method costs far less than transportation and slaughtering. The Poultry Council, which takes care to remove spent laying hens from farms, requires contractors to use the facility and they bring it to every farm in Israel. The facility is also used for killing sick flocks. No more transportation of spent laying hens is allowed!

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.

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.

Effect of dietary nonphytate phosphorus on laying performance and small intestinal epithelial phosphate transporter expression in Dwarf pink-shell laying hens

This study examined the effects of various levels of dietary nonphytate phosphorus on laying performance and the expression patterns of phosphorus metabolism related genes in Dwarf pink-shell Jaying hens. A total of 405 28-week-old Dwarf pink-shell laying hens were fed the same corn-soybean basal meals but containing 0.20%, 0.25%, 0.30%, 0.35% or 0.40% nonphytate phosphorus. The results showed that feed intake, egg production, and average egg weights were quadratically correlated with dietary nonphytate phosphorus content （P 〈 0.05）, and the highest egg production, feed intake and average egg weights were achieved when dietary nonphytate phosphorus was at 0.3% （P 〈 0.05）. mRNA expression of intestinal sodium phosphorus co-transporter linearly decreased when dietary nonphytate phosphorus increased, mRNA and protein expression of intestinal calbindin and vitamin D receptor correlated quadratically with dietary nonphytate phosphorus, and the highest expression was found when dietary available phosphorus was at 0.2,5% to 0.3%. In conclusion, the ideal phosphorus requirement for Dwarf pink-shell layer hens is estimated to be 0.3% in a corn-soybean diet. With this level of phosphorus supplementation, calbindin and vitamin D receptor reached their highest expression.

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.

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).

Sexual maturation in hens is not associated with increases in serum leptin and the expression of leptin receptor mRNA in hypothalamus

Background： In mammals, leptin is an attractive candidate for mediating the metabolic signal and the reproductive function via the specific receptor in hypothalamus. However, till now, the role of leptin on reproduction in birds is less well established. This experiment was conducted to elucidate the role of leptin on the onset of reproduction in bird, as a first step, to detect the changes of peripheral leptin and leptin receptor mRNA expression in hypothalamus between mature and immature hens at the same age. 120 ISA brown pullets at D60 were allocated randomly into two groups, long light （LL） group being raised under artificial light regimes with incrementally increased light phase （from 8 L：]6D to 14 L：]2D） and short light （SL） group raised on consistent light （8 L：16D） for 12 wk. Results： The results showed that pullets in LL group reached sexual maturation 15 d earlier than those in SL group. Serum E2 showed a significant increase with age, but no difference was observed between two groups. Serum leptin concentration decreased significantly from D112 to D136 in LL, and was markedly higher in LL group than that in SL at D112, while there was no significant difference between two groups at D136. Leptin receptor and GnRH-I mRNA expression in hypothalamus were significantly increased with age, yet there was no significant difference between SL and LL chickens at the same age. The expression of FSH-13 and LH-13 mRNA in pituitary was increased with age but did not show significant difference between LL and gland, and decreased from D112 to D136 in LL but not groups at the same age. SL group. GnfiH-I mRNA expression was very rich in pinea n SL group, and there was no difference between two Conclusions： These results indicate that the earlier sexual maturation in hens induced by long-light regime is not accompanied with an increase in serum leptin or leptin receptor gene expression in hypothalamus, or genes expression in HPG axis.