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.

Genome-wide association study for numbers of vertebrae in Dezhou donkey population reveals new candidate genes

Numbers of vertebrae is an important economic trait associated with body size and meat productivity in animals.However,the genetic basis of vertebrae number in donkey remains to be well understood.The aim of this study was to identify candidate genes affecting the number of thoracic(TVn)and the number of lumbar vertebrae(LVn)in Dezhou donkey.A genome-wide association study was conducted using whole genome sequence data imputed from low-coverage genome sequencing.For TVn,we identified 38 genome-wide significant and 64 suggestive SNPs,which relate to 7 genes(NLGN1,DCC,SLC26A7,TOX,WNT7A,LOC123286078,and LOC123280142).For LVn,we identified 9 genome-wide significant and 38 suggestive SNPs,which relate to 8 genes(GABBR2,FBXO4,LOC123277146,LOC123277359,BMP7,B3GAT1,EML2,and LRP5).The genes involve in the Wnt and TGF-βsignaling pathways and may play an important role in embryonic development or bone formation and could be good candidate genes for TVn and LVn.

Spatially resolved transcriptomic profiling of placental development in dairy cow

The placenta plays a crucial role in successful mammalian reproduction.Ruminant animals possess a semi-invasive placenta characterized by a highly vascularized structure formed by maternal endometrial caruncles and fetal placental cotyledons,essential for full-term fetal development.The cow placenta harbors at least two trophoblast cell populations:uninucleate(UNC)and binucleate(BNC)cells.However,the limited capacity to elucidate the transcriptomic dynamics of the placental natural environment has resulted in a poor understanding of both the molecular and cellular interactions between trophoblast cells and niches,and the molecular mechanisms governing trophoblast differentiation and functionalization.To fill this knowledge gap,we employed Stereo-seq to map spatial gene expression patterns at near single-cell resolution in the cow placenta at 90 and 130 days of gestation,attaining high-resolution,spatially resolved gene expression profiles.Based on clustering and cell marker gene expression analyses,key transcription factors,including YBX1 and NPAS2,were shown to regulate the heterogeneity of trophoblast cell subpopulations.Cell communication and trajectory analysis provided a framework for understanding cell-cell interactions and the differentiation of trophoblasts into BNCs in the placental microenvironment.Differential analysis of cell trajectories identified a set of genes involved in regulation of trophoblast differentiation.Additionally,spatial modules and co-variant genes that help shape specific tissue structures were identified.Together,these findings provide foundational insights into important biological pathways critical to the placental development and function in cows.

Effects of Serum Concentration, Synchronization Time and Confluence on the Cell-Cycle Synchronization Efficiency of Goat Fibroblasts

This study aims to evaluate the effect of serum concentration, synchronization time, and confluence degree on the synchronisation efficiency of goat fibroblast cycle. The results indicated that there was no difference in the percentage of nucleated fibroblasts in the G0/G1 stage between serum concentrations of 0.3% and 0.4% (83.89% and 82.69%, respectively, P > 0.05) as well as between serum concentrations of 0.2% and 0.5% (76.95% and 75.46%, respectively, P > 0.05). The percentage of nucleated fibroblasts in the G0/G1 stage was highest at the concentration of 0.3% and lowest in the control group (83.89% vs. 62.67%, P 0.05). The beneficial effect of high confluence was confirmed by the large percentage of nucleated fibroblasts at the G0/G1 stage. The 60% confluency was significantly lower than the 80% and 100% confluency (73.44%, 86.63%, and 87.17%, respectively, P < 0.05). The results indicate that the goat fibroblast cycle synchronization is the most effective at the serum concentration of 0.3%, 72 hours of synchronization and 100% confluency.

Phylogenetic and epidemiological characteristics of H9N2 avian influenza viruses in Shandong Province, China from 2019 to 2021

H9N2 avian influenza virus(AIV) has widely circulated in poultry worldwide and sporadic infections in humans and mammals. During our surveillance of chicken from 2019 to 2021 in Shandong Province, China, we isolated 11 H9N2AIVs. Phylogenetic analyses showed that the eight gene segments of the 11 isolates were closely related to several sublineages of Eurasian lineage: BJ/94-like clades(HA and NA genes), G1-like clades(PB2 and M genes), and SH/F/98-like clades(PB1, PA, NP and NS genes). The isolates showed mutation sites that preferentially bind to humanlike receptors(HA) and mammalian fitness sites(PB2, PB1 and PA), as well as mutations in antigen and drug resistance sites. Moreover, studies with mice revealed four isolates with varying levels of pathogenicity. The average antibody titer of the H9N2 AIVs was 8.60 log2. Based on our results, the epidemiological surveillance of H9N2 AIVs should be strengthened.

Design of live-attenuated animal vaccines based on pseudorabies virus platform

Pseudorabies virus(PRV)is a double-stranded DNA virus with a genome approximating 150 kb in size.PRV contains many non-essential genes that can be replaced with genes encoding heterogenous antigens without affecting viral propagation.With the ability to induce cellular,humoral and mucosal immune responses in the host,PRV is considered to be an ideal and potential live vector for generation of animal vaccines.In this review,we summarize the advances in attenuated recombinant PRVs and design of PRV-based live vaccines as well as the challenge of vaccine application.

Sulforaphane prevents LPS‑induced inflammation by regulating the Nrf2‑mediated autophagy pathway in goat mammary epithelial cells and a mouse model of mastitis

Background Mastitis not only deteriorates the composition or quality of milk,but also damages the health and pro-ductivity of dairy goats.Sulforaphane(SFN)is a phytochemical isothiocyanate compound with various pharmacologi-cal effects such as anti-oxidant and anti-inflammatory.However,the effect of SFN on mastitis has yet to be elucidated.This study aimed to explore the anti-oxidant and anti-inflammatory effects and potential molecular mechanisms of SFN in lipopolysaccharide(LPS)-induced primary goat mammary epithelial cells(GMECs)and a mouse model of mastitis.Results In vitro,SFN downregulated the mRNA expression of inflammatory factors(tumor necrosis factor-α(TNF-α),interleukin(IL)-1βand IL-6),inhibited the protein expression of inflammatory mediators(cyclooxygenase-2(COX2),and inducible nitric oxide synthase(iNOS))while suppressing nuclear factor kappa-B(NF-κB)activation in LPS-induced GMECs.Additionally,SFN exhibited an antioxidant effect by increasing Nrf2 expression and nuclear translocation,up-regulating antioxidant enzymes expression,and decreasing LPS-induced reactive oxygen species(ROS)produc-tion in GMECs.Furthermore,SFN pretreatment promoted the autophagy pathway,which was dependent on the increased Nrf2 level,and contributed significantly to the improved LPS-induced oxidative stress and inflammatory response.In vivo,SFN effectively alleviated histopathological lesions,suppressed the expression of inflammatory factors,enhanced immunohistochemistry staining of Nrf2,and amplified of LC3 puncta LPS-induced mastitis in mice.Mechanically,the in vitro and in vivo study showed that the anti-inflammatory and anti-oxidative stress effects of SFN were mediated by the Nrf2-mediated autophagy pathway in GMECs and a mouse model of mastitis.Conclusions These results indicate that the natural compound SFN has a preventive effect on LPS-induced inflam-mation through by regulating the Nrf2-mediated autophagy pathway in primary goat mammary epithelial cells and a mouse model of mastitis,which may improve prevention strategies for mastitis in dairy goats.

Assessment of the Quality of Frozen-Thawed Semen or Epididymal Sperm in Three Native Vietnamese Pig Breeds

Our aim was to evaluate the quality of ejaculated and epididymal frozen-thawed pig sperm of endangered Vietnam native pig breeds. Ejaculated sperm was collected from live boars and epididymal sperm was collected from slaughtered boars of the MuongTe, Kieng Sat and Co BinhThuan breeds and frozen in 0.25 ml straws using a protocol established earlier for modern pig breeds. We evaluated the sperm quality after thawing in terms of motility and rates of viable and abnormal spermatozoa. Our results revealed that the sperm motility and rates of viable and abnormal frozen-thawed sperm were >30%, >44%, and <14%, respectively. The origin of sperm had an effect on the production of pig embryos in vitro. In the Co BinhThuan breed, ejaculated sperm generated higher cleavage, blastocyst and hatching rates than did the epididymal sperm (60.11% vs 56.02%, 17.23% vs 14.31%, 3.78% vs 2.34%, respectively, P < 0.05). Although no difference in cleavage rate, blastocyst formation rate and the average number of cells/blastocysts, the hatching blastocyst rate was different between the breeds (P > 0.05). In the Co BinhThuan breed, the rate of pregnancy of ejaculated groups was similar to that of the epididymal group. In conclusion, the ejaculated and epididymal sperm of native Vietnamese pigs were successfully frozen. We succeeded in creating embryos in vitro and pregnant pigs after artificial insemination from frozen-thawed semen in three native Vietnamese pig breeds for the first time. The use of the ejaculated sperm improved the production of native pig embryos in vitro efficiency.

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.

Genetic Variation of the VP1 Gene of the Virulent Duck Hepatitis A Virus Type 1(DHAV-1) Isolates in Shandong Province of China

To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1(DHAV-1) isolates,the virulence,cross neutralization assays and the complete sequence of the virion protein 1(VP1) gene of nine virulent DHAV-1 strains,which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007-2008,were tested.The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses(ELD 50 s) and the median lethal doses(LD 50 s),respectively.The results showed that the ELD 50 s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 10 6 /mL to 1.44 × 10 7 /mL,while the LD 50 s were 2.39 × 10 5 /mL to 6.15 × 10 6 /mL.Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates,respectively.Compared with other virulent,moderate virulent,attenuated vaccine and mild strains,the VP1 genes of the 9 strains shared 89.8%-99.7% similarity at the nucleotide level and 92.4%-99.6% at amino acid level with other DHAV-1 strains.There were three hypervariable regions at the C-terminus(aa 158-160,180-193 and 205-219) and other variable points in VP1 protein,but which didn't cause virulence of DHAV-1 change.

The superiority of multi-trait models with genotype-by-environment interactions in a limited number of environments for genomic prediction in pigs

Background: Different production systems and climates could lead to genotype-by-environment(G × E) interactions between populations, and the inclusion of G × E interactions is becoming essential in breeding decisions. The objective of this study was to investigate the performance of multi-trait models in genomic prediction in a limited number of environments with G × E interactions.Results: In total, 2,688 and 1,384 individuals with growth and reproduction phenotypes, respectively, from two Yorkshire pig populations with similar genetic backgrounds were genotyped with the PorcineSNP80 panel.Single-and multi-trait models with genomic best linear unbiased prediction(GBLUP) and BayesC π were implemented to investigate their genomic prediction abilities with 20 replicates of five-fold cross-validation.Our results regarding between-environment genetic correlations of growth and reproductive traits(ranging from 0.618 to 0.723) indicated the existence of G × E interactions between these two Yorkshire pig populations. For single-trait models, genomic prediction with GBLUP was only 1.1% more accurate on average in the combined population than in single populations, and no significant improvements were obtained by BayesC π for most traits. In addition, single-trait models with either GBLUP or BayesC π produced greater bias for the combined population than for single populations. However, multi-trait models with GBLUP and BayesC π better accommodated G × E interactions,yielding 2.2% – 3.8% and 1.0% – 2.5% higher prediction accuracies for growth and reproductive traits, respectively,compared to those for single-trait models of single populations and the combined population. The multi-trait models also yielded lower bias and larger gains in the case of a small reference population. The smaller improvement in prediction accuracy and larger bias obtained by the single-trait models in the combined population was mainly due to the low consistency of linkage disequilibrium between the two populations, which also caused the BayesC π method to always produce the largest standard error in marker effect estimation for the combined population.Conclusions: In conclusion, our findings confirmed that directly combining populations to enlarge the reference population is not efficient in improving the accuracy of genomic prediction in the presence of G × E interactions, while multi-trait models perform better in a limited number of environments with G × E interactions.

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.

Isolation, Identification and Pathogenicity Analysis of Streptococcus suis Type 2

[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determination of growth curve and correlation curve between OD 600 values and viable counts,drug susceptibility tests,pathogenicity analysis,and histopathological observations were carried out.[Results]The Streptococcus strain isolated from infected pigs was identified as Streptococcus suis type 2,which was named TA01 strain.TA01 strain reached the growth peak at 6-8 h post-incubation,and viable counts gradually declined after 8 h of incubation.The correlation equation between OD 600 values and viable counts is y=24.659 x-1.076 1,R^2=0.996 7.TA01 strain was sensitive to penicillin,erythromycin,florfenicol and oxacillin,and resistant to ciprofloxacin,polymyxin B and clindamycin.According to the results of pathogenicity analysis,all the mice in 3.6×10^9 cfu/mouse group died within 48,and these dead mice exhibited acute pyaemia septica.Based on the Reed-Muench formula,it was calculated that LD 50 of TA01 strain was 1.137×10^8 cfu/mouse.Pathological examination showed obvious blue-stained bacteria clusters,accompanied by neutrophil infiltration.[Conclusions]TA01 strain was a virulent strain of Streptococcus suis type 2.Compared with Streptococcus strains which were isolated and reported in China,TA01 strain exhibited strong virulence and rapid proliferation.

Identification of an H1N1 subtype of swine influenza virus and serological analysis

To investigate the epizootic of swine influenza virus(SIV),60 nasal swabs were collected from a clinical cases of pig farm in Tai’an City,Shandong Province of China in April 2017.SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced.An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1).Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch,seven genome segments belonged to avian-like H1N1 influenza virus lineage.The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G,which is a typical molecular biological characteristic.Five potential N-glycosylation sites(N14,N26,N277,N484 and N543) were found in the HA gene.To further investigate the epidemiology of SIV in this farm,the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens.The results showed that the total positive rate was 65.43%.The positive rates of single virus infection detected by EAH1N1,2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35,30.85 and 7.47%,respectively.The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm.These data provide evidence of an epizootic of SIV.

Expression patterns of OCT4, NANOG, and SOX2 in goat preimplantation embryos from in vivo and in vitro

The transcription factors, including OCT4, NANOG, and SOX2, played crucial roles in the maintenance of self-renewal and pluripotency in embryonic stem cells （ESCs）. They expressed in preimplantation mammalian development with spa- tio-temporal pattern and took part in regulation of development. However, their expression and roles in goat had not been reported. In the present study, the expression of OCT4, NANOG, and SOX2 in goat preimplantation embryos both in vivo and in vitro were detected by real-time RCR and immunofluorescence. For in vivo fertilized embryos, the transcripts of OCT4, NANOG, and SOX2 could be detected from oocytes to blastocyst stage, their expression in morula and blastocyst stages was much higher than other stage. OCT4 protein was detected from oocyte to blastocyst, but the fluorescence was more located-intensive with nuclei from 8-cell stage, its expression present in both inner cell mass （ICM） and trophoblast cells （TE） at blastocyse stage. NANOG protein was similar to OCT4, the signaling of fluorescence completely focused on cell nuclei, while the SOX2 firstly showed nuclei location in morula. Comparing to in vivo fertilized embryo, the mRNA of these three transcription factors could be detected at 8-cell stage in parthenogenetic embryos （in vitro）. Thereafter, the expressional level rose gradually along with embryo development. The locations of OCT4 and NANOG proteins were similar to in vivo fertilized embryos, and they located in cell nuclei from morula to blastocyst stage, while SOX2 protein firstly could be detected in cell nuclei at 8-cell stage. These differences suggested that OCT4, NANOG, and SOX2 played different function in regulating development of goat preimplantation embryos. These results may provide a novel insight to goat embryo development and be useful for goat ESCs isolation.

Simultaneous detection of duck hepatitis A virus types 1 and 3, and of duck astrovirus type 1, by multiplex RT-PCR

Dear Editor,Duck virus hepatitis(DVH)is caused by at least threedifferent RNA viruses,including duck hepatitis A virus(DHAV),duck astrovirus type 1(DAstV-1),and duckastrovirus type 2(DAstV-2).The first of these,DHAV,has been classified into three serotypes by

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.

Effects of Pyridoxine on Selected Appetite Regulating Peptides mRNA Expression in Hypothalamic PVN/ARC Nuclei and Gastrointestinal Tract Tissues

An experiment was conducted to investigate the effect of dietary pyridoxine on the gene expression of appetite-regulating peptides in the hypothalamus and gastrointestinal tract of rabbits. Thirty-two rabbits were randomly divided into 2 treatments for 8 weeks (16 replicates/group and 1 rabbit/replicate). The treatments were fed a basal diet (control, measured pyridoxine content is 4.51 mg/kg) and the basal diet with a pyridoxine supplementation at 10 mg/kg (pyridoxine, measured pyridoxine content is 14.64 mg/kg). The results showed that dietary pyridoxine did not significantly alter the mRNA levels of neuropeptide Y, agouti related peptide, pro-opiomelanocortin and cocaine, amphetamine regulated transcript, peptide YY and cholecystokinin in arcuate nucleus, peptide YY in jejunum and ileum, and cholecystokinin in duodenum, jejunum and ileum (P > 0.05). Compared with the control, the mRNA levels of corticotropin-releasing hormone and melanocortin 4 receptor in paraventricular nuclei and peptide YY in duodenum were significantly decreased after pyridoxine treatment (P 0.05). In conclusion, the appetite genes of melanocortin 4 receptor and corticotropin-releasing hormone in paraventricular nuclei and peptide YY in duodenum are involved in the pyridoxine-caused hyperphagia.

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.

Breed identification using breed‑informative SNPs and machine learning based on whole genome sequence data and SNP chip data

Background Breed identification is useful in a variety of biological contexts.Breed identification usually involves two stages,i.e.,detection of breed-informative SNPs and breed assignment.For both stages,there are several methods proposed.However,what is the optimal combination of these methods remain unclear.In this study,using the whole genome sequence data available for 13 cattle breeds from Run 8 of the 1,000 Bull Genomes Project,we compared the combinations of three methods(Delta,FST,and In)for breed-informative SNP detection and five machine learning methods(KNN,SVM,RF,NB,and ANN)for breed assignment with respect to different reference population sizes and difference numbers of most breed-informative SNPs.In addition,we evaluated the accuracy of breed identification using SNP chip data of different densities.Results We found that all combinations performed quite well with identification accuracies over 95%in all scenarios.However,there was no combination which performed the best and robust across all scenarios.We proposed to inte-grate the three breed-informative detection methods,named DFI,and integrate the three machine learning methods,KNN,SVM,and RF,named KSR.We found that the combination of these two integrated methods outperformed the other combinations with accuracies over 99%in most cases and was very robust in all scenarios.The accuracies from using SNP chip data were only slightly lower than that from using sequence data in most cases.Conclusions The current study showed that the combination of DFI and KSR was the optimal strategy.Using sequence data resulted in higher accuracies than using chip data in most cases.However,the differences were gener-ally small.In view of the cost of genotyping,using chip data is also a good option for breed identification.