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.

Effects of arginine replacement with L-citrulline on the arginine/nitric oxide metabolism in chickens:An animal model without urea cycle

Background This study examined the efficacy of L-citrulline supplementation on the arginine/nitric oxide metabolism,and intestinal functions of broilers during arginine deficiency.A total of 288 day-old Arbor Acre broilers were randomly assigned to either an arginine deficient basal diet(NC diet),NC diet+0.50%L-arginine(PC diet),or NC diet+0.50%L-citrulline(NCL diet).Production performance was recorded,and at 21 days old,chickens were euthanized for tissue collection.Results The dietary treatments did not affect the growth performance of broilers(P>0.05),although NC diet increased the plasma alanine aminotransferase,urate,and several amino acids,except arginine(P<0.05).In contrast,NCL diet elevated the arginine and ornithine concentration higher than NC diet,and it increased the plasma citrulline greater than the PC diet(P<0.05).The nitric oxide concentration in the kidney and liver tissues,along with the plasma and liver e NOS activities were promoted by NCL diet higher than PC diet(P<0.05).In the liver,the activities of arginase 1,ASS,and ASL,as well as,the gene expression of i NOS and OTC were induced by PC diet greater than NC diet(P<0.05).In the kidney,the arginase 1,ASS and ASL enzymes were also increased by PC diet significantly higher than the NC and NCL diets.Comparatively,the kidney had higher abundance of n NOS,ASS,ARG2,and OTC genes than the liver tissue(P<0.05).In addition,NCL diet upregulated(P<0.05)the m RNA expression of intestinal nutrient transporters(EAAT3 and PEPT1),tight junction proteins(Claudin 1 and Occludin),and intestinal mucosal defense(MUC2 and p Ig R).The intestinal morphology revealed that both PC and NCL diets improved(P<0.05)the ileal VH/CD ratio and the jejunal VH and VH/CD ratio compared to the NC fed broilers.Conclusion This study revealed that NCL diet supported arginine metabolism,nitric oxide synthesis,and promoted the intestinal function of broilers.Thus,L-citrulline may serve as a partial arginine replacement in broiler’s diet without detrimental impacts on the performance,arginine metabolism and gut health of chickens.

Functional roles of taurine,L-theanine,Lcitrulline,and betaine during heat stress in poultry

Heat stress(HS)is an important environmental stress factor affecting poultry production on a global scale.With the rise in ambient temperature and increasing effects of global warming,it becomes pertinent to understand the effects of HS on poultry production and the strategies that can be adopted to mitigate its detrimental impacts on the performance,health,welfare,immunity,and survival of birds.Amino acids(AAs)have been increasingly adopted as nutritional modifiers in animals to ameliorate the adverse effects of HS.They are essential for protein synthesis,growth,maintenance,reproduction,immunity,stress response,and whole-body homeostasis.However,HS tends to adversely affect the availability,transport,absorption,and utilization of these AAs.Studies have investigated the provision of these AAs to poultry during HS conditions,and variable findings have been reported.Taurine,L-theanine,and L-citrulline are non-essential amino acids that are increasingly gaining attention as nutritional supplements in HS animals.Similarly,betaine is an amino acid derivative that possesses favorable biological properties which contributes to its role as a functional additive during HS.Of particular note,taurine is negligible in plants,while betaine,L-theanine,and L-citrulline can be found in selected plants.These nutrients are barely found in feed ingredients,but their supply has been shown to elicit important physiological roles including anti-stress effects,anti-oxidative,anti-inflammatory,gut promoting,and immunomodulatory functions.The present review provides information on the use of these nutritionally and physiologically beneficial nutrients as functional additives to poultry diets during HS conditions.Presently,although several studies have reported on the positive effects of these additives in human and murine studies,however,there is limited information regarding their utilization during heat stress in poultry nutrition.Therefore,this review aims to expound on the functional properties of these nutrients,their potentials for HS alleviation,and to stimulate further researches on their biological roles in poultry nutrition.

Dietary L-citrulline supplementation modulates nitric oxide synthesis and antioxidant status of laying hens during summer season

Background:L-citrulline(L-Cit),a non-protein amino acid,has been implicated in several physiological functions including anti-inflammatory,anti-oxidative,and hypothermic roles,however,there is a paucity of information with regards to its potential in poultry production.Methods:This study was designed to investigate the effects of dietary L-Cit supplementation on the production performance,nitric oxide production,and antioxidant status of laying hens during summer period.Hy-Line Brown laying hens(n=288,34 weeks old)were allotted to four treatment,6 replicates of 12 chickens each.Dietary treatments of control(basal diets),0.25%,0.50%and 1.00%L-Cit supplementation were fed to chickens for eight(8)weeks.Production performance,free amino acid profiles,nitric oxide production,and antioxidant properties were measured.Blood samples were collected at the 4th and 8th weeks of the experiment.Results:Air temperature monitoring indicated an average daily minimum and maximum temperatures of 25.02°C and 31.01°C respectively.Dietary supplementation with L-Cit did not influence(P>0.05)the production performance,and rectal temperature of laying hens.Egg shape index was increased(P<0.05)with increasing levels of L-Cit.Serum-free content of arginine,citrulline,ornithine,tryptophan,histidine,GABA,and cystathionine were elevated,but taurine declined with L-Cit diets.Plasma nitric oxide(NOx)concentration was highest at 1%L-Cit.Likewise,nitric oxide synthase(NOS)activity for total NOS(tNOS)and inducible NOS(iNOS)were upregulated with increasing L-Cit levels,although,tNOS was not affected at the 4th week.Anti-oxidant enzymes including catalase and superoxide dismutase(SOD)were increased with L-Cit supplementation,however,SOD activity was unchanged at 4th week,while total anti-oxidant capacity increased at the 8th week.L-Cit supplementation attenuated the extent of lipid peroxidation,and also inhibited glutathione peroxidase activity.Conclusion:Dietary L-Cit supplementation modulated systemic arginine metabolism,nitric oxide synthesis,antioxidant defense system,and increased the egg shape index of laying hens during the summer season.1%L-Cit supplementation proved most effective in potentiating these effects and may be adopted for feed formulation strategies.

The optimal dietary arginine level of laying hens fed with low-protein diets

Background:Arginine(Arg)is an essential amino acid(EAA)in poultry,an important substrate for protein synthesis and a precursor of several molecules.Supplementation of EAAs with low protein(LP)diet increases the utilization efficiency of dietary crude protein(CP).However,if the EAA requirement is changed in hens fed a LP diet remains to be elucidated.The aim of the present study was to evaluate the optimal level of dietary Arg in the LP diet of hens.A total of 1350 Hy-Line Brown laying hens were randomly allocated to six dietary treatments:a basal diet(16%CP,positive control),or an isoenergetic LP diet(14%CP,0.80%Arg)supplemented 0,0.05%,0.10%,0.15%,and 0.20%L-Arg,corresponding to 0.80%,0.85%,0.90%,0.95%and 1.00%dietary Arg,respectively.Results:The feed efficiency was decreased(P<0.05)by 0.80%and 1.00%Arg-LP diets,compared to control.Within LP diets,dietary Arg level had significant quadratic effects(P<0.05)on laying rate,egg mass,and feed efficiency.Compared to control,the plasma CAT activity or T-AOC content were decreased by 0.80%(P<0.001).However,the hens offered 0.85%and 0.90%Arg-LP diets had higher CAT activity(P<0.001)than 0.80%Arg-LP diet.In contrast,1.00%Arg-LP group had the highest MDA and the lowest T-AOC content in plasma,liver,duodenal and jejunal mucosa(P<0.05).Compared to control,the villus height was decreased by 0.80%,0.95%and 1.00%Arg-LP diets,while the villus height to crypt depth(V/C)ratio was reduced by 0.95%and 1.00%Arg-LP diets in duodenum.Conclusion:The result demonstrates that LP diet(14%CP)deficient in Arg(0.80%Arg)result in augmented oxidative damage and impaired development of intestinal mucosa.According to the quadratic broken-line regression model,the optimal dietary arginine levels for Hy-Line Brown laying hens fed with low protein diet(14%CP)aged 33 to 40 weeks are 0.85%,0.86%,and 0.86%to obtained the maximum laying rate,egg mass,and feed efficiency,respectively.

Effect of dexamethasone on hypothalamic expression of appetite-related genes in chickens under different diet and feeding conditions

Background： Glucocorticoids （GCs） are involved in the control of appetite in birds and mammals. The effect of GCs on feed intake in birds depends on their dietary energy level. But the regulation mechanism of GCs on appetite is still unclear in chickens facing to different energy level. An experiment was conducted to investigate the effect of dexamethasone （DEX） on hypothalamic expression of appetite-related peptides in chickens fed high/low fat diet and under fasting/feeding condition. Results： An interaction between DEX injection and dietary energy level was found on hypothalamic corticotropin- releasing hormone （CRH） gene expression in fasted chickens （P 〈 0.05）. The chickens, given a DEX injection and a low fat diet treatment, had the highest CRH mRNA levels than any of the fasted chickens given treatments （P 〈 0.05）. Under fasting conditions, the DEX treatment significantly increased hypothalamic neuropeptide Y （NPY） and GC receptors mRNA levels （P 〈 0.05）. Under re-feeding conditions, DEX treatment significantly decreased hypothalamic expression levels of NPY and agouti-related peptide （AgRP） but significantly increased the level of hypothalamic CRH expression （P 〈 0.05）. Conclusion： A regulatory network formed by NPY, AgRP and CRH is associated with the appetite-control by GCs. The result suggests that the regulation of GCs on orexigenic neuropeptides expression is dependent at least partially on dietary energy level and feeding state.

L-Arginine/nitric oxide regulates skeletal muscle development via muscle fibre-specific nitric oxide/mTOR pathway in chickens

L-Arginine (L-Arg), the precursor of nitric oxide (NO), plays an important role in muscle function. Fasttwitchglycolytic fibres are more susceptible to age-related atrophy than slow-twitch oxidative fibres.The effect of L-Arg/NO on protein metabolism of fast- and slow-twitch muscle fibres was evaluated inchickens. In Exp. 1, 48 chicks at 1 day old were divided into 4 groups of 12 birds and subjected to 4treatments: basal diet without supplementation or supplemented with 1% L-Arg, and water supplementedwith or without L-nitro-arginine methyl ester (L-NAME, 18.5 mM). In Exp. 2, 48 chicks weredivided into 4 groups of 12 birds fed with the basal diet and subjected to the following treatments: tapwater (control), tap water supplemented with L-NAME (18.5 mM), or molsidomine (MS, 0.1 mM), or18.5 mM L-NAME t 0.1 mM MS (NAMS). The regulatory effect of L-Arg/NO was further investigatedin vitro with myoblasts obtained from chicken embryo pectoralis major (PM) and biceps femoris (BF).In vivo, dietary L-Arg supplementation increased breast (t14.94%, P < 0.05) and thigh muscle mass(t23.40%, P < 0.05);whereas, MS treatment had no detectable influence. However, L-NAME treatmentblocked the beneficial influence of L-Arg on muscle development. L-Arg decreased (P < 0.05) proteinsynthesis rate, phosphorylated mTOR and ribosomal protein S6 kinase beta-1 (p70S6K) levels in breastmuscle, which was recovered by L-NAME treatment. In vitro, L-Arg or sodium nitroprusside (SNP)reduced protein synthesis rate, suppressed phosphorylated mTOR/p70S6K and decreased atrogin-1 andmuscle RING finger 1 (MuRF1) in myoblasts from PM muscle (P < 0.05). L-NAME abolished the inhibitoryeffect of L-Arg on protein synthesis and the mTOR/p70S6K pathway. However, myoblasts from BF muscleshowed the weak influence. Moreover, blocking the mTOR/p70S6K pathway with rapamycin suppressedprotein synthesis of the 2 types of myoblasts;whereas, the protein expression of atrogin-1 and MuRF1levels were restricted only in myoblasts from PM muscle. In conclusion, L-Arg/NO/mTOR/p70S6Kpathway enhances protein accumulation and muscle development in fast-twitch glycolytic muscle inchickens. L-Arg/NO regulates protein turnover in a muscle fibre specific way, which highlights the potentialclinical application in fast-twitch glycolytic muscle fibres.