首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The Japanese quail has several advantages as a low‐fat meat bird with high immunity against diseases. Cathelicidins (CATHs) are antimicrobial peptides that play an important role in innate immunity. The aim of this study was to characterize the CATH cluster in the Japanese quail (Coturnix japonica). The Japanese quail CATH (CjCATH) cluster, contains four CATH genes, as in the chicken. The coding sequences of CjCATHs exhibited >85.3% identity to chicken CATHs. The predicted amino acid sequences of the four CjCATH genes contained the cathelin‐like domain characteristic of CATH proteins. Polymorphisms were detected in the open reading frames (ORFs) of all CjCATH sequences. Two amino acid substitutions were observed in the antimicrobial region of the mature peptide of CjCATH2, and predicted to influence peptide function. CjCATH1 is expressed in lung, heart, bone marrow and bursa of Fabricius (BF). CjCATH2 is expressed in bone marrow. CjCATH3 is expressed in lung, heart, bone marrow, BF, tongue and duodenum. CjCATHB1 is expressed in bone marrow and BF. This study is the first to characterize CATH genes in the Japanese quail, and identifies novel antimicrobial peptide sequences belonging to the cathelicidin family, which may play a role in immunity in this species.  相似文献   

2.
This study evaluated the antimicrobial effect of essential oils (EO) and organic acids (OA) against Salmonella Enteritidis in chicken feed and during an in vitro model that mimics the chicken digestive process. The minimal inhibitory concentration (MIC) of allyl isothiocyanate (AITC), carvacrol (CV), propionic acid (PROP) and caproic acid (CAP) were individually determined. Then, based on the MICs of each compound, combinations of EOs and/or OAs were tested to evaluate their synergic antimicrobial effect. The synergic effect of AITC and CAP was the most efficient against the bacterial strain tested. Commercial feed was inoculated with a 5‐strain cocktail of S. Enteritidis and treated with different doses of AITC + CAP to evaluate their effect on the growth/survival of the pathogen. In addition, the simulated digestion model was used to access the antimicrobial effect of AITC + CAP added to the feed towards S. Enteritidis and Lactobacillus plantarum. Synergistic effect was found between AITC (0.065 mM) and CAP (17.5 mM) against S. Enteritidis in chicken feed, where S. Enteritidis was reduced to undetectable levels (<1.00 log CFU/g). AITC (1.95 mM) + CAP (45 mM) also decreased (p < 0.05) the population of S. Enteritidis in the simulated digestion, while the growth of L. plantarum was not affected. Therefore, the addition of AITC + CAP in feed might be a potential natural antimicrobial able to prevent economic losses caused for Salmonella in chicken.  相似文献   

3.
In recent years host antimicrobial peptides and proteins have been recognised as key mediators of the innate immune response in many vertebrate species, providing the first line of defense against potential pathogens. In chickens a number of cationic antimicrobial peptides have been recently identified. However, although these peptides have been studied extensively in the avian gastrointestinal tract, little is known about their function in the chicken reproductive organs and embryos. Chicken Liver Expressed Antimicrobial Peptide-2 (cLEAP-2) has been previously reported to function in protecting birds against microbial attack. The aim of this study was to investigate the expression of cLEAP-2 gene in the chicken reproductive organs, as well as in chicken embryos during embryonic development, and to determine whether cLEAP-2 expression in the chicken reproductive organs was constitutive or induced as a response to Salmonella enteritidis infection. RNA was extracted from ovary, oviduct, testis and epididymis of sexually mature healthy and Salmonella infected birds, as well as from chicken embryos until day ten of embryonic development. Expression analysis data revealed that cLEAP-2 was expressed in the chicken ovary, testis and epididymis as well as in embryos during early embryonic development. Quantitative real-time PCR analysis revealed that cLEAP-2 expression was constitutive in the chicken epididymis, but was significantly up regulated in the chicken gonads, following Salmonella infection. In addition, expression of cLEAP-2 during chicken embryogenesis appeared to be developmentally regulated. These data provide evidence to suggest a key role of cLEAP-2 in the protection of the chicken reproductive organs and the developing embryos from Salmonella colonization.  相似文献   

4.
The enormous production potential of buffaloes has never been accomplished due to various reproductive insufficiencies. Among them, post‐partum anoestrus, a multifactorial disorder, is predominant but any genetic association is yet to be established. This study focused to identify novel polymorphisms in heat‐shock protein 70 (HSP70) gene and its possible association with post‐partum anoestrus in Murrah buffaloes. A 579‐bp fragment from 5′ untranslated region of HSP70 gene was amplified by polymerase chain reaction from blood genomic DNA of 614 animals maintained under similar management conditions. In phase‐I experiment, custom sequencing and restriction enzyme (RE) digestion of the amplified fragment were performed in 40 buffaloes with similar post‐partum oestrous conditions over previous consecutive three or more gestations—20 animals each showing post‐partum anoestrus (>120 days after parturition) and normal cyclicity (<65 days after parturition). While in phase‐II experiment, herd screening by RE analysis was performed in remaining 574 animals. Four transversions at T‐75G, C+31G, T+38G and C+97A and three transition mutations at T‐153C, T+33C and A+44G positions were observed. Polymorphism at T+38G site revealed significant (p < .05) variation, where homozygous G was present only in post‐partum anoestrous animals while nucleotide T was present randomly in both groups of phase‐I animals whereas phase‐II experiments revealed homozygous G in 55 animals. Regression analysis in relation to average post‐partum interval against genotypic frequencies at T+38G also depicted significant association. HSP70 gene polymorphism at T+38G position can therefore be used as genetic marker for excluding probable post‐partum anoestrous buffaloes from herd for breeding programmes.  相似文献   

5.
Twenty‐six dogs with known adverse food reactions were fed whole chicken for 14 days. From this group, 12 dogs with cutaneous manifestations following exposure to chicken meat were selected and randomly divided into two groups (n = 6). Each group was then fed hydrolysed chicken or hydrolysed soy for 14 days in a blinded crossover design with a 17‐day washout period between each diet. Assessments of a CADESI (Canine Atopic Dermatitis Extent and Severity Index) score and pruritus were performed throughout the entire study, and combined in a global score (GS). Serum was collected weekly for the measurement of chicken‐ and soy‐specific IgG and IgE. Dogs displayed the most severe clinical response when eating whole chicken compared to baseline (P < 0.001). The GS was significantly reduced in 11 of the 12 dogs when fed hydrolysed chicken were compared to those fed whole chicken (3.58 ± 2.81 versus 20.38 ± 14.65, P < 0.01). Serum immunoglobulin G and E responses were variable and did not show relationship with specific dietary exposure.  相似文献   

6.
Salmonella enterica serovar Rissen has been recognized as one of the most common serovar among humans and pork production systems in different parts of the world, especially Asia. In the United States, this serovar caused outbreaks but its epidemiologic significance remains unknown. The objectives of this study were to compare the phenotypic (antimicrobial susceptibility) and genotypic attributes of Salmonella Rissen isolated in Thailand (Thai) and the United States (US). All the Thai isolates (n = 30) were recovered from swine faecal samples. The US isolates (n = 35) were recovered from swine faecal samples (n = 29), cattle (n = 2), chicken (n = 2), dog (n = 1) and a ready‐to‐eat product (n = 1). The antimicrobial susceptibility of isolates was determined using the Kirby‐Bauer disk diffusion method with a panel of 12 antimicrobials. Pulse‐field gel electrophoresis (PFGE) was used to determine the genotypic diversity of isolates. All Thai isolates showed multidrug resistance (MDR) with the most frequent antibiotic resistance shown against ampicillin (100%), sulfisoxazole (96.7%), tetracycline (93.3%), streptomycin (90%) and chloramphenicol (30%). About half of the isolates of USA origin were pan‐susceptible and roughly 30% were resistant to only tetracycline (R‐type: Te). Salmonella Rissen isolated from Thailand and the USA in this study were found to be clonally unrelated. Genotypic analyses indicated that isolates were clustered primarily based on the geographic origin implying the limited clonality among the strains. Clonal relatedness among different host species within the same geography (USA) was found. We found genotypic similarity in Thai and US isolates in few instances but with no epidemiological link. Further studies to assess propensity for increased inter‐regional transmission and dissemination is warranted.  相似文献   

7.
We aimed to evaluate the reproductive performance of Nelore lactating cows submitted to a resynchronization 12 days after timed artificial insemination (TAI) with or without a long‐acting progesterone (P4‐LA) treatment. Nelore cows were submitted to a P4/oestradiol‐based TAI protocol (D0 = insemination). On D12, cows in the control group (n = 184) received a new P4 intravaginal device (0.96 g), whereas cows in the P4‐LA group (n = 192) received the P4 device and 75 mg P4‐LA. Cows identified as non‐pregnant (n = 120) by regression of corpus luteum using colour Doppler ultrasonography on D20 had the P4 device removed and received 500ug of sodium cloprostenol, 1 mg of oestradiol cypionate and 300 IU of eCG and were re‐inseminated on D22. There was no difference (p > 0.10) in the pregnancy rate at D20, D30 and D60 after first TAI between the control (69%, 59.7% and 57%, respectively) and P4‐LA (67%, 55.7%, and 55.2%, respectively) groups. Pregnancy losses were similar between both groups (p > 0.1). For cows submitted to the second TAI, the pre‐ovulatory follicle size did not differ (p > 0.1), but the oestrous detection and pregnancy rates were greater (p < 0.05) in the P4‐LA group (92.2% [59/64] and 60.9% [39/64], respectively) than in controls (75% [42/56] and 44.6% [25/56]). The cumulative pregnancy rate after two TAIs did not differ (p > 0.1) between control (73.3% [135/184]) and P4‐LA (76% [146/192]) groups. The use of P4‐LA at 12 days after TAI potentially increases the pregnancy rates for a new early resynchronization strategy associated with the Doppler imaging for pregnancy diagnosis and results in an alternative to perform two TAIs in 22 days in beef cows.  相似文献   

8.
In order to explore the effect of strain on diverging post‐hatch muscle properties, muscle regulation during embryo development was investigated in selected and unselected breeds. Four broiler strains were used: JingNing (JN) chicken (a Chinese native chicken), HuangYu (HY) broiler, BaiYu (BY) broiler and Hyline layer (commercial crossbred chickens). Results showed that the four breeds had almost the same characteristic during different incubation periods. BY broilers moved more than JN and Hyline layers from Hamburger & Hamilton stage (HH)24 to HH31 (P < 0.05). HY broilers moved more than JN and Hyline layers from HH27 to HH31 (P < 0.01). All the embryos were heavier daily from HH24 to ED18 (P < 0.05); broilers presented greater body weights than JN and hyline layers (P > 0.05); broilers presented smaller fiber diameter than JN chickens before HH31 (P > 0.05). From then on, JN chicken exhibited smaller fiber diameter compared to the broilers (P > 0.05). Western blotting indicated all the breeds had continuous insulin‐like growth factor‐I (IGF‐I) expression, with the highest expression level in broilers from HH19 to HH24 and highest expression level in JN chicks from HH27 to HH31. The results indicated that the diverging growth among breeds was already shown in embryonic stages; the different expression patterns of IGF‐I may be involved in cell proliferation and differentiation.  相似文献   

9.
We describe multiple‐aetiology infections involving non‐O157 Shiga toxin‐producing Escherichia coli (STEC) identified through laboratory‐based surveillance in nine FoodNet sites from 2001 to 2010. A multiple‐aetiology infection (MEI) was defined as isolation of non‐O157 STEC and laboratory evidence of any of the other nine pathogens under surveillance or isolation of >1 non‐O157 STEC serogroup from the same person within a 7‐day period. We compared exposures of patients with MEI during 2001–2010 with those of patients with single‐aetiology non‐O157 STEC infections (SEI) during 2008–2009 and with those of the FoodNet population from a survey conducted during 2006–2007. In total, 1870 non‐O157 STEC infections were reported; 68 (3.6%) were MEI; 60 included pathogens other than non‐O157 STEC; and eight involved >1 serogroup of non‐O157 STEC. Of the 68 MEI, 21 (31%) were part of six outbreaks. STEC O111 was isolated in 44% of all MEI. Of patients with MEI, 50% had contact with farm animals compared with 29% (P < 0.01) of persons with SEI; this difference was driven by infections involving STEC O111. More patients with non‐outbreak‐associated MEI reported drinking well water (62%) than respondents in a population survey (19%) (P < 0.01). Drinking well water and having contact with animals may be important exposures for MEI, especially those involving STEC O111.  相似文献   

10.
In cynomolgus macaques (Macaca fascicularis), widely used in drug metabolism studies, CYP2C9, CYP2C76, CYP2D6, CYP3A4, and CYP3A5, important drug‐metabolizing enzymes, are abundantly expressed in liver and metabolize cytochrome P450 substrates. CYP2C9 (c.334A>C), CYP2C76 (c.449TG>A), CYP2D6 (c.891A>G), CYP3A4 (IVS3 + 1G>del), and CYP3A5 (c.625A>T) substantially influence metabolic activity of enzymes, and thus are important variants in drug metabolism studies. In this study, a real‐time PCR method was developed for genotyping these variants. The validity of the methods was verified by genotyping two wild type, two heterozygous, and two homozygous DNAs and was used to genotype 41 cynomolgus macaques (from Cambodia, Indonesia, the Philippines, or Vietnam) for the five variants, along with another important variant CYP2C19 (c.308C>T). The CYP2C9 and CYP2C19 variants were found only in Cambodian and Vietnamese animals, while the CYP2C76 and CYP2D6 variants were found only in Indonesian and Philippine animals. The CYP3A4 and CYP3A5 variants were not found in any of the animals analyzed. Mauritian animals, genotyped using next‐generation sequencing data for comparison, possessed the CYP2C19 and CYP2D6 variants, but not the other variants. These results indicated differences in prevalence of these important variants among animal groups. Therefore, the genotyping tool developed is useful for drug metabolism studies using cynomolgus macaques.  相似文献   

11.
Canine sulfonamide hypersensitivity (HS) has been associated with a variant in the cytochrome b5 reductase gene (CYB5R3 729A>G), which encodes a drug‐detoxifying enzyme. Study objectives were to determine variant allele frequency in Doberman Pinschers (DOBE), a breed which may be predisposed to sulfonamide HS, and to characterize the effects of CYB5R3 729G on gene expression and function. CYB5R3 729A>G allele frequencies were compared between DOBE (n = 24) vs. non‐Doberman (non‐DOBE; n = 60) dogs. CYB5R3mRNA expression, protein expression, and reduction of sulfamethoxazole hydroxylamine were compared between banked canine liver samples of 729AA vs. GG genotype. The 729G allele was overrepresented in DOBE (1.00) vs. non‐DOBE dogs (0.567, p < .0001). mRNA and protein expressions as well as cyt b5 reductase activity were similar between livers of AA and GG genotype. All Doberman Pinschers in this study were homozygous for CYB5R3 729G, which could contribute to this breed's apparent predisposition to sulfonamide HS. However, CYB5R3 729G does not alter sulfamethoxazole detoxification capacity, so a direct role could not be demonstrated. It is possible that this marker is linked to another contributing variant.  相似文献   

12.
The cephalosporin antimicrobial drug cefquinome was administered to yellow cattle intravenously (i.v.) and intramuscularly (i.m.) at a dose of 1 mg/kg of body weight in a two‐period crossover study. The pharmacokinetic (PK) properties of cefquinome in serum, inflamed tissue‐cage fluid (exudate), and noninflamed tissue‐cage fluid (transudate) were studied using a tissue‐cage model. The in vitro and ex vivo activities of cefquinome in serum, exudate, and transudate against a pathogenic strain of Pasteurella multocida (P. multocida) were determined. A concentration‐independent antimicrobial activity of cefquinome was confirmed for levels lower than 4 × MIC. Integration of in vivo pharmacokinetic data with the in vitro MIC provided mean values for the time that drug levels remain above the MIC (T > MIC) in serum was 14.10 h after intravenous and 14.46 h after intramuscular dosing, indicating a likely high level of effectiveness in clinical infections caused by P. multocida of MIC 0.04 μg/mL or less. These data may be used as a rational basis for setting dosing schedules, which optimize clinical efficacy and minimize the opportunities for emergence of resistant organisms.  相似文献   

13.
  相似文献   

14.
  相似文献   

15.
The aim of the study was to identify beta‐haemolytic streptococci in the vagina of bitches who had delivered healthy litters and bitches who had delivered litters in which neonatal deaths occurred. Fifty‐one bitches divided into two groups were used. Group 1 (G1) included 28 bitches that had delivered healthy litters and group 2 (G2) included 23 bitches that had delivered puppies who died in the neonatal period. Two vaginal samples were taken, one in proestrus and the other at the end of gestation (EG). Beta‐haemolytic Streptococcus (BS) was isolated from 16 bitches (57%) in G1 and from 21 bitches (91%) in G2. The bacteriological cultures, serological tests (Streptex®) and PCR assay allowed identification of Streptococcus canis and Streptococcus dysgalactiae in G1 and G2. Ultramicroscopic studies allowed the observation of M Protein and capsules in strains of S. dysgalactiae and S. canis in G1 and G2. The S. canis strains isolated from G2 showed thicker capsules than S. canis strains isolated from G1 (234 ± 24.2 vs 151.23 ± 28.93 nm; p < .001.). No differences were observed in capsule thickness between strains of S. dysgalactiae isolated from G1 and G2 (210 ± 13.54 vs 211.66 ± 19.67 nm; p > .70). All strains of beta‐haemolytic Streptococcus isolated were penicillin sensitive. Penicillin was administered from EG to 5 days post‐partum in 10 G2 females with isolation of BS (G2A). Saline solution was administered in eleven G2 females with isolation of BS (G2B). Ninety per cent of the puppies survived in G2A and 25% survived in G2B. Our results suggest BS is involved in canine neonatal deaths.  相似文献   

16.
This study examined the effect of single IU administration of cephapirin on clinical recovery, clearance of uterine bacteria and reproductive performance of postpartum buffaloes with subclinical endometritis (SCE). Buffaloes (n = 86) at 35 days postpartum (DPP) with >10% polymorphonuclear (PMN) cells in endometrial cytosmears were designated as positive (SCEP, n = 29), and buffaloes with ≤10% PMN cell were designated as negative (SCEN, n = 57) for SCE. Out of 29 positive buffaloes, 15 were administered a single intrauterine dose of cephapirin benzathine on 40 DPP (SCEP‐CB), while the remaining 14 animals were kept as untreated control (SCEP‐C). All animals were observed regularly for oestrous signs and were again subjected to cytobrush sampling on the first postpartum (FPP) oestrus. Buffaloes positive for SCE at 35 DPP were later considered “recovered” if their PMN cells dropped to ≤5% on the FPP oestrus. Presence of Escherichia coli, Arcanobacterium pyogenes and Fusobacterium necrophorum in uterus was detected based upon PCR amplification of genes related to bacteria‐specific virulence factors. A total of 66.7% of SCEP‐CB group buffaloes recovered as compared to 28.6% in SCEP‐C (χ2 = 4.21; p < 0.05). Rate of bacterial clearance did not differ between treated (38.5%) and untreated buffaloes (8.3%) (χ2 = 1.67; p > 0.05). The median days to first service did not differ significantly (p > 0.05) among the three groups, whereas cephapirin administration reduced (p < 0.05) the days open by 14 days in SCEP‐CB compared to SCEP‐C buffaloes. SCEP‐CB buffaloes were as likely to conceive as SCEN, whereas SCEP‐C had 0.28 hazard ratio for pregnancy. In conclusion, a single treatment with cephapirin benzathine at 40 DPP improved the reproductive performance of buffaloes with subclinical endometritis.  相似文献   

17.
Pretreatment D‐dimer levels have been reported to predict survival in several types of malignancies in human patients. The objective of this study was to evaluate the prognostic value of pretreatment D‐dimer level in dogs with intermediate to high‐grade non‐Hodgkin lymphoma (NHL). In a prospective, randomized, double‐blind study of F14512 vs etoposide phosphate, we assessed the prognostic value of pretreatment plasma D‐dimer level in 48 client‐owned dogs diagnosed with intermediate to high‐grade NHL. The correlation between pretreatment plasma D‐dimer level and various clinical features, progression‐free survival (PFS) and overall survival (OS) was analysed. The median value of pretreatment plasma D‐dimer level was 0.4 μg/mL (range: 0.1‐14.3 μg/mL). High pretreatment plasma D‐dimer level (>0.5 μg/mL) was detected in 44% (21/48) of dogs. High D‐dimer levels were not correlated with naive vs relapsed lymphoma, clinical stage, substage, immunophenotype or treatment group. D‐dimer levels >0.5 μg/mL were significantly associated with inferior median PFS (54 vs 104 days, P = .011) and OS (93 vs 169 days, P = .003). In the multivariate analysis, high D‐dimer levels remained an independent predictor for worse PFS (HR: 3.21, 95% CI: 1.57‐6.56, P = .001) and OS (HR: 3.87, 95% CI: 1.88‐7.98; P < .001). This study suggests that pretreatment plasma D‐dimer level can serve as a predictor of prognosis in dogs with intermediate to high‐grade NHL. Further studies are warranted to confirm these findings.  相似文献   

18.
Antimicrobial peptides expressed on different epithelial lining are major components of the innate immune system. Based on the deduced amino acid sequence of Bubalus bubalis lingual antimicrobial peptide (LAP) cDNA (Accession No. DQ458768), five overlapping peptides LAP23–55, LAP42–64, LAP21–64, LAP1–26 and LAP1–64 were synthesized using solid phase fluorenylmethoxycarbonyl (Fmoc) chemistry. Circular Dichroism spectroscopy of synthesized peptides revealed predominantly β-structure for LAP23–55, LAP42−64 and LAP21–64 with less α-helix in different solutions. Quantitation of secondary structure indicated the highest β-structure for all these three peptides in membrane mimetic SDS solution. The helicogenic solvent TFE could not induce helix in LAP23–55 however TFE induced helical propensity was observed in LAP42–64 and LAP21–64. The quantitation of secondary structure indicated the highest ordered structure for LAP23–55 followed by LAP42–64 and LAP21–64. The antibacterial activity of LAP23–55 was found to be more potent against Staphylococcus aureus, Listeria monocytogens, Escherichia coli and Salmonella typhimurium followed by LAP42–64 and LAP21–64. Minimum inhibitory concentration (MIC) also showed similar trend with lowest value for LAP23–55 followed by LAP42–64 and LAP21–64. Haemolysis and cytotoxicity was observed above 3 fold for LAP21–64, above six fold for LAP23–55 and LAP42–64 of their MIC. The LAP1–26 and LAP1–64 could not produce any characteristic CD spectra and did not show any antimicrobial activity, indicating that N- terminal of the peptide negates the antimicrobial activity.  相似文献   

19.
We studied the effect of dietary roughage species and their combinations on forage intake and growth rate of ewes during winter in a pastoral‐farming area of northeast China. Twenty‐five Northeast crossbred ewes (fine‐wool sheep × Small‐tailed Han sheep) were randomly selected and divided into five groups (G1, G2, G3, G4 and G5). During a 30 day feeding trial, each group of ewes were offered the same basal diet (composed of 0.36 kg chopped maize stalk (10 mm), 0.14 kg corn meal, 0.05 kg soybean meal and 1.2 g NaCl) and one of the five supplementary roughage mixes, namely 100% Leymus chinensis hay (G1), 100% Vigna radiata stalk (G2), L. chinensis hay plus Suaeda glauca (G3), V. radiata stalk plus S. glauca (G4) and L. chinensis hay plus V. radiata stalk and S. glauca (G5). The results showed that roughage mixes had significant influences on daily roughage intake and daily weight gain of ewes. Ewes had greater daily roughage intake when supplemented with three species of roughage compared to the roughage with one species; however, there was no significant difference between G1 and G2, G3 and G4, or between G4 and G5. The average daily gain of ewes was also greater when they were supplemented with the roughage combination of L. chinensis, V. radiata stalk and S. glauca. No difference in average daily weight gain was observed between the G4 and G5 treatments (P > 0.05). The lowest average daily weight gain was observed when the ewes were supplemented with V. radiata stalk alone (G2) (P < 0.05). The results indicated that supplying ewes with various roughages simultaneously in winter could improve their forage intake and average daily weight gain compared to offering the ewes only one type of dietary roughage. Further, feeding roughage supplements containing a diverse mix of roughage species represents one method for increasing roughage utilization in livestock production during winter in the pastoral‐farming areas of northeastern China.  相似文献   

20.
This study investigated the effect of dietary nutmeg oil (NO) on growth performance, blood parameters, lipid peroxidation and heat shock protein (HSP) 70 expression in Korean native chicken (KNC) reared under hot temperature. We allocated 273 meat‐type KNCs (Hanhyup‐3, 4‐week‐old, body weight [BW] = 539.93 ± 1.75 g) to the following three treatments with seven replicate pens (13 birds/pen) per treatment. Three treatment diets were as follows: (a) Control, basal diet without NO supplementation; (b) NO 250; and (c) NO 500, basal diet supplemented with 250 and 500 ppm NO respectively. Diets and water were provided ad libitum throughout the 6‐week feeding trial. During overall period (0–6 weeks), no differences (p > 0.05) were observed in BW gain (BWG), feed intake (FI) and feed conversion rate (FCR) among treatments. However, the FI at 0–3 weeks decreased (p < 0.05) quadratically with increasing NO levels. Most blood parameters did not differ (p > 0.05) among treatments, although the monocyte level of the NO 500 group was considerably lower (p > 0.05) than that of the other groups. Furthermore, dietary NO did not affect serum triglyceride, cholesterol, total protein, albumin, calcium, phosphorus and alanine aminotransferase (ALT) levels (p > 0.05); however, it linearly decreased serum aspartate aminotransferase (AST) level (p < 0.05). Additionally, serum malondialdehyde (MDA) concentration decreased (p < 0.05) and heart MDA concentration was lower (p = 0.08) with increasing dietary NO supplementation. After a 3‐hr heat (35°C) challenge, the rectal temperature (RT) reduced (p < 0.05) linearly with increasing NO levels. Dietary NO did not affect liver HSP70 (p > 0.05) gene expression. In conclusion, NO potentially enhanced the ability of chickens to alleviate heat stress. Furthermore, our findings suggest that lipid oxidation inhibition by dietary NO likely mediated the enhanced heat‐stress tolerance of the chickens.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号