Investigation of the outbreaks of abortions and orchitis in livestock in Namibia during 2016-2018.

This study investigated outbreaks of seemingly related abortions and orchitis which occurred in the Khomas, Omaheke and Otjozondjupa regions of Namibia from 2016 to 2018, affecting cattle, sheep and goats. Fifty-nine questionnaires were administered, and 48 were completed giving an 81.4% return. The outbreaks were limited to Namibia's east and central regions, mainly on farms rearing cattle, sheep and goats and on farms with a mixture of these species. There was no significant difference between Khomas and other regions on abortion reporting at the farm level [X2 (1, N = 48) = 0.0002, p = 0.987851]. However, there was a significant difference in the abortions at the animal level among the three regions [X2 (2, N = 6246) = 239.8339, p = .00001]. In addition, the proportions of abortions calculated at the animal level at each farm were significantly different when the Khomas region was compared to the other regions. Seventeen cattle sera, 35 sheep sera, 52 caprine sera, 18 bovine liver samples, one caprine liver, five aborted cattle foetuses, two cattle placentas, 18 testes (one bull, eight bucks and nine rams) and ten bull sheath scrapings were collected and tested. Histopathology, microbiology, serology, immunohistochemistry, real-time PCR and mineral analytical techniques were used to establish the aetiology of the abortion and orchitis outbreaks. The gross and histopathological findings on the 18 testicles were characteristic of chronic orchitis. In aborted foetuses, significant histopathological findings included meconium aspiration, funisitis and cardiomyopathy. Placentitis and endometritis were the primary pathologies observed in cows. The bacteria isolated from microbiological samples included Enterococcus spp. (65.5% [19/29]), Enterobacter spp. (6.9% [2/29]) and Streptococcus spp. (10.3% [3/29]), Trueperella pyogenes (3.4% [1/29]), Stenotrophomonas maltophilia (3.4% [1/29]), Staphylococcus epidermidis (3.4% [1/29]), Providencia rettgeri (3.4% [1/29]) and Acinetobacter lwoffii (3.4% [1/29]), mostly opportunistic bacteria. On mineral analysis, 28%, 33%, 83%, 33% and 17% (n = 18) of cattle livers were low in copper, zinc, manganese, selenium and iron, respectively. Twenty-three percent (12/52) of the caprine sera were positive for Brucella melitensis on the Rose Bengal and complement fixation tests. Thirty-five ovine sera were tested for B. melitensis, B. ovis and Coxiella burnetii, and the prevalence for each was 2.9% (1/35). PCR tests on foetuses were all negative for Brucella spp., Coxiella burnetii, Chlamydia spp., Listeria monocytogenes, Salmonella spp., Campylobacter fetus spp., Leptospira pathogenic strains, bovine viral diarrhoea virus, Rift Valley fever virus, Anaplasma phagocytophilum and bovine herpes virus 4 Campylobacter fetus spp. and Trichomonas foetus spp. The authors concluded that Brucella spp., Enterococcus spp., Escherichia coli, Streptococcus spp., Trueperella pyogenes and Coxiella burnetii could have contributed to this outbreak. Micronutrient imbalances and pathogenic abiotic nanoparticles were also identified as possible contributors to the abortion outbreaks.

Evaluation of colonization, variable lipoprotein-based serological response, and cellular immune response of Mycoplasma hyorhinis in experimentally infected swine.

Mycoplasma hyorhinis (Mhr) is a commensal of the upper respiratory tract that can be shed by nasal secretions and transmitted by direct contact in neonatal and nursery pigs. Lesions associated with Mhr infection include polyserositis and arthritis; however, systemic Mhr disease pathogenesis is not well characterized. This study aimed to investigate the immunopathogenesis and bacterial dissemination pattern of Mhr using single and multiple inoculation approaches in a caesarian-derived colostrum-deprived (CDCD) pig model. Animals in three treatment groups were inoculated once (Mhr 1; n = 12) or four (Mhr 2; n = 8) times with Mhr or sham-inoculated (NC group; n = 3) nasally and by tonsillar painting. Inoculum consisted of a triple cloned Mhr field isolate (4.5 × 107 CFU/mL) in Friis medium. Clinical signs were evaluated daily during the study. Serum and oral fluid antibody (IgA and IgG) response and cellular immune response were assessed using a recombinant chimeric VlpA-G-based indirect ELISA and by ELISpot, respectively. The presence of Mhr in oral fluids, nasal and oropharyngeal swabs were evaluated by qPCR. At 6 wpi, pigs were euthanized and evaluated for gross lesions consistent with Mhr and bacterial colonization in tonsils by qPCR. No clinical signs or gross lesions consistent with Mhr-associated disease were observed throughout the study. For Mhr 2 group, the presence of IgA and IgG in serum and oral fluids were detected at 2 and 4 weeks post-inoculation (wpi), respectively, while in Mhr 1, only IgA was detected in oral fluids at 6 wpi. The proportion of animals shedding Mhr in nasal secretions varied from 20 to 40 % in the Mhr 1 and 62.5-100% in the Mhr 2 group. However, the proportion of animals shedding Mhr in oropharyngeal swabs was consistent through the study (60 %) in Mhr 1 and fluctuated from 20 % to 87.5 % in Mhr 2 group. The lack of clinical signs and the presence of Mhr specific humoral response and bacterial colonization indicates that the multiple inoculation experimental model may mimic subclinical natural infection in the field. In addition, the humoral and transient cellular response did not result in bacterial clearance. Based on these results, animals would have to be exposed multiple times to mount a detectable immune response.

Histological and transcriptomic analysis of adipose and muscle of dairy calves supplemented with 5-hydroxytryptophan.

In mammals, peripheral serotonin is involved in regulating energy balance. Herein, we characterized the transcriptomic profile and microstructure of adipose and muscle in pre-weaned calves with increased circulating serotonin. Holstein bull calves (21 ± 2 days old) were fed milk replacer supplemented with saline (CON, 8 mL/day n = 4) or 5-hydroxytryptophan (5-HTP, 90 mg/day, n = 4) for 10 consecutive days. Calves were euthanized on d10 to harvest adipose and muscle for RNA-Sequencing and histological analyses. Twenty-two genes were differentially expressed in adipose, and 33 in muscle. Notably, Interferon gamma inducible protein-47 was highly expressed and upregulated in muscle and adipose (avg. log FC = 6.5). Enriched pathways in adipose tissue revealed serotonin's participation in lipid metabolism and PPAR signaling. In muscle, enriched pathways were related to histone acetyltransferase binding, Jak-STAT signaling, PI3K-Akt signaling and cell proliferation. Supplementation of 5-HTP increased cell proliferation and total cell number in adipose and muscle. Adipocyte surface area was smaller and muscle fiber area was not different in the 5-HTP group. Manipulating the serotonin pathway, through oral supplementation of 5-HTP, influences signaling pathways and cellular processes in adipose and muscle related to endocrine and metabolic functions which might translate into improvements in calf growth and development.

In ovo green light photostimulation during the late incubation stage affects somatotropic axis activity.

Targeted green light photostimulation during the last stage of broiler incubation increases expression of the somatotropic axis. The purpose of this study was to further shorten the in ovo green light photostimulation and determine the critical age for photostimulation in broilers embryos, as a future strategy for broiler incubation. Fertile broilers eggs (n = 420) were divided into 5 treatment groups. The first group was incubated under standard conditions (in the dark) as the negative control group. The second was incubated under intermittent monochromatic green light using light-emitting diode lamps with an intensity of 0.1 W/m2 at shell level from embryonic day (ED) 0 of incubation until hatch, as a positive control. The third, fourth, and fifth groups were incubated under intermittent monochromatic green light from ED 15, 16, and 18 of incubation, respectively, until hatch. All treatment groups showed elevated somatotropic axis expression compared with the negative control, with the group incubated under monochromatic green light from ED 18 until hatch showing results closest to the positive control. This suggests that broiler embryos can be exposed to in ovo green light photostimulation from a late stage of incubation (when transferring the eggs to the hatchery) and exhibit essentially the same outcome as obtained by photostimulation during the entire incubation period.

Response of selenoproteins gene expression profile to mercuric chloride exposure in chicken kidney.

Kidney is a primary target organ for mercuric chloride (HgCl2) toxicity. Selenium (Se) can exert antagonistic effect on heavy metals-induced organ toxicity by regulating the expression of selenoproteins. The objective of this study was to investigate the effect of HgCl2 on the gene expression of selenoproteins in chicken kidney. Sixty male Hyline brown chickens were randomly and evenly divided into two groups. After acclimatization for one week, chickens were provided with the standard diet as well as non-treated water (CON group), and standard diet as well as HgCl2-treated water (250 ppm, HgCl2 group). After seven weeks, kidney tissues were collected to examine the mRNA expression levels of 25 selenoproteins genes and protein expression levels of 4 selenoproteins. Moreover, correlation analysis and principal component analysis (PCA) were used to analyze the expression patterns of 25 selenoproteins. The results showed that HgCl2 exposure significantly decreased the mRNA expression of Glutathione peroxidase 1 (GPX1), GPX4, Thioredoxin reductase 2 (TXNRD2), Iodothyronine deiodinase 1 (DIO1), Methionine-Rsulfoxide reductase 1 (SELR), 15-kDa selenoprotein (SEP15), selenoprotein I (SELI), SELK, SELM, SELN, SELP, SELS, SELT, SELW, and SEPHS2. Meanwhile, HgCl2 exposure significantly increased the mRNA expression of GPX3, TXNRD1, and SELU. Western blot analysis showed that the expression levels of GPX3, TXNRD1, SELK, and SELN were concordant with these mRNA expression levels. Analysis results of selenoproteins expression patterns showed that HgCl2-induced the main disorder expression of selenoproteins with antioxidant activity and endoplasmic reticulum resident selenoproteins. In conclusion, selenoproteins respond to HgCl2 exposure in a characteristic manner in chicken kidney.

Tissue distribution of transcription for 29 lipid metabolism-related genes in Takifugu rubripes, a marine teleost storing lipid predominantly in liver.

The tissue distribution pattern of lipid is highly diverse among different fish species. Tiger puffer has a special lipid storage pattern, storing lipid predominantly in liver. In order to better understand the lipid physiology in fish storing lipid in liver, the present study preliminarily investigated the tissue distribution of transcription for 29 lipid metabolism-related genes in tiger puffer, which are involved in lipogenesis, fatty acid oxidation, biosynthesis and hydrolysis of glycerides, lipid transport, and relevant transcription regulation. Samples of eight tissues, brain, eye, heart, spleen, liver, intestine, skin, and muscle, from fifteen juvenile tiger puffer were used in the qRT-PCR analysis. The intestine and brain had high transcription of lipogenic genes, whereas the liver and muscle had low expression levels. The intestine also had the highest transcription level of most apolipoproteins and lipid metabolism-related transcription factors. The transcription of fatty acid ß-oxidation-related genes was low in the muscle. The peroxisomal fatty acid oxidation may dominate over mitochondrial ß-oxidation in the liver and intestine of tiger puffer, and the MAG pathway probably predominates over the G3P pathway in re-acylation of absorbed lipids in the intestine. The intracellular glyceridases were highly transcribed in the brain, eye, and heart. In conclusion, in tiger puffer, the intestine could be a center of lipid metabolism whereas the liver is more likely a pure storage organ for lipid. The lipid metabolism in the muscle could also be inactive, possibly due to the very low level of intramuscular lipid.

The presence of Mycoplasma bovis in colostrum.

In herds with Mycoplasma bovis circulation, colostrum is often considered infectious. However, in contrast to milk, the presence of M. bovis in colostrum was not previously evidenced. In this survey, the presence of M. bovis DNA was determined with real-time PCR in 368 colostrum samples from 17 herds, recently infected with M. bovis. Only 1.9% of the samples tested positive, with 13 herds having no positive samples and an overall within-herd prevalence of 3.2% (SD: 4.9%; Range: 0-30.0%). These results show that in infected herds M. bovis DNA can be retrieved in colostrum. To what extend colostrum is infectious remains to be determined.

Identification and verification of differentially expressed genes in yak mammary tissue during the lactation cycle.

Yaks (Bos grunniens) live primarily in the Qinghai-Tibetan plateau (altitude: 2000-5000 m). Their milk presents unusual characteristics, containing large amounts of solids including fat and protein, and it is, therefore, important to understand the genetic makeup of the yak. To identify potentially critical genes playing a role in yak mammary tissue from colostrum to mature milk phase of lactogenesis, the early lactation (colostrum) stage (ELS; day 1 after parturition) and mature lactation (milk) stage (MLS; day 15) were chosen for comparison. An ELS-specific cDNA library was established by suppression subtractive hybridization and 25 expressed sequence tags at ELS were identified by sequencing and alignment. To further confirm our results the expression levels of 21 genes during the lactation cycle were measured using quantitative real-time RT-PCR (qRT-PCR). The qRT-PCR results confirmed 9 significantly up-regulated genes at ELS vs. MLS in yak mammary tissue, in which the l-amino acid oxidase 1 (LAO1) and collagen, type I, alpha I (COL1A1) were the most significantly up-regulated. During the lactation cycle, the highest expression of some milk fat genes (i.e., XDH and FABP3) in yak mammary tissue appears earlier than that in dairy cow. Our data also indicate MYC potentially playing a central role through putative regulation of COL1A1, CD44, SPARC, FASN and GPAM.

Transcriptional analysis of RstA/RstB in avian pathogenic Escherichia coli identifies its role in the regulation of hdeD-mediated virulence and survival in chicken macrophages.

Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis in poultry, which is characterized by systemic infections such as septicemia, air sacculitis, and pericarditis. APEC uses two-component regulatory systems (TCSs) to handle the stressful environments present in infected hosts. While many TCSs in E. coli have been well characterized, the RstA/RstB system in APEC has not been thoroughly investigated. The involvement of the RstA regulator in APEC pathogenesis was demonstrated during previous studies investigating its role in APEC persistence in chicken macrophages and respiratory infections. However, the mechanism underlying this phenomenon has not been clarified. Transcriptional analysis of the effect of rstAB deletion was therefore performed to improve the understanding of the RstA/RstB regulatory mechanism, and particularly its role in virulence. The transcriptomes of the rstAB mutant and the wild-type strain E058 were compared during their growth in the bloodstreams of challenged chickens. Overall, 198 differentially expressed (DE) genes were identified, and these indicated that RstA/RstB mainly regulates systems involved in nitrogen metabolism, iron acquisition, and acid resistance. Phenotypic assays indicated that the rstAB mutant responded more to an acidic pH than the wild-type strain did, possibly because of the repression of the acid-resistance operons hdeABD and gadABE by the deletion of rstAB. Based on the reported RstA box motif TACATNTNGTTACA, we identified four possible RstA target genes (hdeD, fadE, narG, and metE) among the DE genes. An electrophoretic mobility shift assay confirmed that RstA binds directly to the promoter of hdeD, and ß-galactosidase assays showed that hdeD expression was reduced by rstAB deletion, indicating that RstA directly regulates hdeD expression. The hdeD mutation resulted in virulence attenuation in both cultured chicken macrophages and experimentally infected chickens. In conclusion, our data suggest that RstA affects APEC E058 virulence partly by directly regulating the acidic resistance gene hdeD.

Transcriptome analysis and the effects of polyunsaturated fatty acids on the immune responses of the critically endangered angtze sturgeon (Acipenser dabryanus).

The poor understanding of nutrition needed has become a significant obstruction to artificial conservation of Yangtze sturgeon (Acipenser dabryanus) and the relationship between ployunsaturated fatty acid nutrition and the immune response of Yangtze sturgeon is remains unclear. To explore this relationship, the immune response was determined by the activities of serum immune-related enzymes and the transcriptome pattern in the spleen after feeding different fat source diets for 7 weeks. In addition, the gene expression pattern after a lipopolysaccharide (LPS) challenge was investigated in the presence of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Long-term feeding of the fish oil diets increased the serum immune-related enzyme activities, including lysozyme, acid phosphatase, and alkaline phosphatase of Yangtze sturgeon. More than 653,999 transcripts with an N50 length of 1047 bp were obtained and a final set of 280,408 unigenes was generated. After annotating the unigenes, 3549 genes were assigned to the immune system and 2839 were identified to participate in the response to the different fat sources. A transcriptome assay showed the fish oil diets moderately upregulated immune-related signaling pathways in the spleen of Yangtze sturgeon, including NLR signaling, platelet activation, Fc gamma R-mediated phagocytosis, Th17 cell differentiation, and Th1 and Th2 cell differentiation. The quantitative polymerase chain reaction (qPCR) results of candidate genes for these pathways showed similar results. The LPS challenge study revealed that DHA and EPA moderately upregulated the candidate immune-related genes and modulated excessive activation of the immune pathway by the pathogen. This study confirmed the immunomodulatory function of unsaturated fatty acids in Yangtze sturgeon. This research will provide a reference for the preparation of artificial diets for Yangtze sturgeon.

Effects of low-dose oleuropein diet supplementation on the oxidative status of skeletal muscles and plasma hormonal concentration of growing broiler chickens.

1. Oleuropein (Ole) is a major phenolic compound in Olea europaea, with anti-oxidative, anti-obesity, and anti-inflammatory properties. To explore the effect of Ole on the physiology and metabolism of poultry, this study, evaluated the effects of feeding low-dose Ole on the growth performance, metabolic hormonal status, muscle oxidative status in growing broiler chickens.2. Thirty-two 8-day-old chickens were assigned to four different treatments, and fed either 0 (control), 0.1, 0.5, or 2.5 ppm Ole-supplemented diets for 2 weeks.3. There were no differences in the body weight gain, feed consumption, and feed efficiency during the feeding periods between the groups tested. Birds fed Ole 0.5- and 2.5 ppm-supplemented diets exhibited a significant decrease in muscle carbonyl content compared to the control group. In the group fed Ole 0.5 ppm, the mRNA expression levels of mitochondrial ROS-reducing factors: avian uncoupling protein and manganese superoxide dismutase, as well as peroxisome proliferator-activated receptor γ coactivator 1-α, sirtuin-1 and -3 (each of which co-ordinately induce the transcription of the previous two factors) were upregulated compared to the control group, and the changes were independent of plasma noradrenaline and thyroid hormone levels. The group fed Ole-2.5 ppm did not show such transcriptional changes, but exhibited a higher corticosterone concentration.4. This study demonstrates that ingesting a low dose of Ole can reduce muscle oxidative damage, and that the suppression machinery may differ depending on the amount of Ole ingested by growing broiler chickens.

Impact of dietary chitosan oligosaccharide and its effects on coccidia challenge in broiler chickens.

1. Two experiments were conducted, the first to determine the optimum inclusion of chitosan oligosaccharide (COS) in broiler diets to support growth performance, digestive functions, intestinal morphology, and immune organs. The second experiment evaluated the immune-protective properties of COS on broiler chickens during coccidia challenge (CC).2. Experiment 1 investigated the effect of graded dietary concentration of COS in the diets of broiler chickens using eight cage replicates for each of the six diets. A corn-soybean meal-based diet was used as the basal diet and supplemented with 0.0, 0.5, 1.0, 1.5, 2.0, or 2.5 g of COS/kg feed to form the six treatments.3. The diet supplemented with 1.0 g COS/kg of feed provided the optimal inclusion level for broiler chickens regarding body weight (BW) gain, jejunal villus height, villus height to crypt depth ratio, and ileal energy digestibility at d 22 of age.4. Experiment 2 investigated the immune-protective properties of COS in broiler chickens during CC. A total of 224 male broiler chicks were randomly assigned to eight replicate cages in a 2 × 2 factorial arrangement of treatments with two COS concentrations (0 or 1 g of COS/kg of diet), with or without CC.5. On d 18 of age, birds in the CC group received twice the recommended coccidia vaccine dose of 30 doses/kg BW.6. Coccidia challenge reduced (P < 0.05) and dietary COS increased (P < 0.05) BW gain, and feed intake. Dietary COS mitigated (P < 0.05) the CC-induced effects on gain:feed. Dietary COS supplementation attenuated the CC-induced effects (P < 0.05) on the expression of occludin genes.7. In conclusion, dietary COS improved performance, and the immune-related beneficial impact of COS supplementation was associated with reduced expression of pro-inflammatory cytokine genes.

Hepatotoxicity and renal toxicity induced by gamma-radiation and the modulatory protective effect of Ficus carica in male albino rats.

It is well-known that gamma radiation initiates generation of free radicals which prompting serious cellular damages in biological systems. In the present study, we investigated the role of Ficus carica, a natural antioxidant substance, in modulating changes in liver and kidney functions, antioxidant enzyme's gene expression, and apoptosis, in male albino rats exposed to gamma radiation. A total of 40 rats were used in this experiment and divided equally into 4 groups: Group 1, rats administered distilled H2O (Control); Group 2, rats administered F. carica; Group 3, rats irradiated; and Group 4, rats treated with F. carica and irradiated. Groups 3 and 4 were exposed to whole-body gamma radiations at a dose level of 8 Gy and with a dose rate of 0.762 Gy/min. F. carica was administered to rats by gavage, for 3 consecutive weeks, before exposure to radiation. Five rats were sacrificed from each group at intervals of 24 and 72 h after cessation of treatment. The results revealed marked increases in alanine aminotransferase and aspartate aminotransferase levels in liver, a decrease in albumin level and increase in urea level in kidney. Irradiation resulted in cytotoxic effects as indicated by elevation in antioxidant enzyme's gene expression at 24 h, the opposite was observed at 72 h. Immunohistochemical analysis revealed that cytochrome c and p53 expressions significantly increased following exposure to radiation. Oral administration of F. carica pre-irradiation as a natural product plays a modulatory protective and anti-apoptotic role against cells damaged by free radicals induced by whole-body irradiation.

In vitro characterization and analysis of probiotic species in the chicken intestine by real-time polymerase chain reaction.

Two experiments, 1 in vitro and 1 in vivo study, were conducted to analyze probiotic species characteristics and survival in the intestine of broiler birds. The in vitro study characterized the effect of bile salt supplementation and pH on the proliferation of Lactobacillus reuteri, Pediococcus acidilactici, Bifidobacterium animalis, and Enterococcus faecium. L. reuteri and P. acidilactici growth was maximal when the media was supplemented with 1.0% bile salt, whereas B. animalis and E. faecium growth was maximal when the media was supplemented with 0.5% bile salt. Altering the pH between 2.5 and 5.8 did not significantly (P > 0.05) alter the proliferation of L. reuteri and B. animalis. Decreasing the pH from 5.8 to 2.0 decreased P. acidilactici growth, whereas it increased the E. faecium proliferation. The in vivo study quantified the concentration of L. reuteri, P. acidilactici, B. animalis, E. faecium, and L. salivarius in different intestinal sections from birds supplemented with and without synbiotic containing the above 5 bacteria species. Birds were supplemented with and without synbiotic for 18 d, after which all birds were fed the same basal diet with no synbiotic. At 72 h of feeding, the basal diet with no synbiotics, when the probiotic species in the feed is expected not to confound the recovery of probiotic species from the intestine, intestinal contents were collected. L. reuteri, P. acidilactici, E. faecium, and L. salivarius were below detectable amount in the control group. L. reuteri concentration expressed as copy numbers/g and as percentage of total bacteria was highest in the jejunum and ileum, respectively. E. faecium concentration was highest in the ileum. The copy number of P. acidilactici increased at the duodenum and plateaued after duodenum. L. salivarius concentration was highest in the jejunum. It can be concluded that real-time PCR can be applied to quantify the concentrations of probiotic species in the intestine and probiotic species differ in their ability to colonize different sections of the intestine.

H3N2 canine influenza virus and Enterococcus faecalis coinfection in dogs in China.

BACKGROUND: In May 2017, 17 dogs in a German Shepherd breeding kennel in northern China developed respiratory clinical signs. The owner treated the dogs with an intravenous injection of Shuang-Huang-lian, a traditional Chinese medicine, and azithromycin. The respiratory signs improved 3 days post-treatment, however, cysts were observed in the necks of eight dogs, and three of them died in the following 2 days. CASE PRESENTATION: Quantitative real-time PCR was used to detect canine influenza virus (CIV). All of the dogs in this kennel were positive and the remaining 14 dogs had seroconverted. Two of the dogs were taken to the China Agricultural University Veterinary Teaching Hospital for further examination. Two strains of influenza virus (A/canine/Beijing/0512-133/2017 and A/canine/Beijing/0512-137/2017) isolated from the nasal swabs of these dogs were sequenced and identified as avian-origin H3N2 CIV. For the two dogs admitted to the hospital, hematology showed mild inflammation and radiograph results indicated pneumonia. Cyst fluid was plated for bacterial culture and bacterial 16 s rRNA gene PCR was performed, followed by Sanger sequencing. The results indicated an Enterococcus faecalis infection. Antimicrobial susceptibility tests were performed and dogs were treated with enrofloxacin. All 14 remaining dogs recovered within 16 days. CONCLUSIONS: Coinfection of H3N2 CIV and Enterococcus faecalis was detected in dogs, which has not been reported previously. Our results highlight that CIV infection might promote the secondary infection of opportunistic bacteria and cause more severe and complicated clinical outcomes.

Dietary selenium supplementation enhances antiviral immunity in chickens challenged with low pathogenic avian influenza virus subtype H9N2.

Selenium supplementation in poultry feeds has been known to have beneficial effects on the bird health and performance; however antiviral effects of selenium have remained largely unknown. In this study, we have evaluated the effects of supplementation of chicken diets with organic (Selenium Enriched Yeast; SEY) and inorganic selenium (Sodium Selenite; SS) on low pathogenicity avian influenza virus (H9N2) shedding in the cloacal and oropharyngeal swab samples as well as examined the expression of immune related genes. Chickens were fed two doses (High- 0.30 mg/kg of feed; Low- 0.15 mg/kg of feed) of selenium supplementation for 2 weeks followed by low pathogenicity avian influenza virus challenge. Our results showed that the cloacal shedding of virus in all the selenium supplemented groups was significantly lower when compared to the non-supplemented control groups. In addition, the oropharyngeal shedding of virus in chickens fed with organic selenium supplementation was significantly lower than that in the chickens that received either inorganic selenium supplemented feed or controls. Furthermore, the expression of interferon stimulated genes (Viperin, OAS: 2'-5' oligoadenylate synthetase and MDA5: melanoma differentiation-associated gene) in the cecal tonsils was significantly elevated in the selenium treated groups when compared to controls. Additionally, a significantly higher transcription of interferon (IFN)-α, IFN-ß and IFN-γ genes in the cecal tonsils and spleens of chickens receiving SEY-L and SS-H supplemented feed was also observed at post virus challenge time points compared to untreated controls. The results of this study demonstrated that supplementation of chicken diets with selenium, can enhance antiviral defense and thus, may have a beneficial effect in controlling viral infections in poultry.

Responses to dietary levels of methionine in broilers medicated or vaccinated against coccidia under Eimeria tenella-challenged condition.

BACKGROUND: Coccidiosis is a prevalent problem in chicken production. Dietary addition of coccidiostats and vaccination are two approaches used to suppress coccidia in the practical production. Methionine (Met) is usually the first limiting amino acid that plays important roles in protein metabolism and immune functions in chickens. The present study is aimed to investigate whether increasing dietary Met levels will improve the anticoccidial effects in broilers medicated or vaccinated against coccidia under Eimeria (E.) tenella-challenged condition. Two thousand male Partridge Shank broiler chicks were obtained from a hatchery. After hatch, birds were weighed, color-marked and allocated equally into two anticoccidial treatments, namely medicated and vaccinated groups. Chicks were either fed, from 1 d of age, diets containing coccidiostat (narasin) or diets without the coccidiostat but were inoculated with an anticoccidial vaccine at 3 d of age. At 22 d of age, 1080 chicks among them were randomly allocated evenly into 6 groups under a 2 × 3 treatment with 2 anticoccidial programs and 3 dietary methionine (Met) levels. Chicks medicated or vaccinated against coccidia were fed diets containing 0.45%, 0.56% or 0.68% of Met from 22 to 42 d of age. All chicks were orally introduced with an amount of 5 × 104 sporulated oocysts of E. tenella at 24 d of age. The growth performance, serum anti-oxidative indexes, intestinal morphology, cecal lesion scores, fecal oocyst counts and immune parameters were measured. RESULTS: The results showed increasing dietary Met level from 0.45% to 0.56% and 0.68% improved weight gain and feed conversion of broilers medicated against coccidia. In contrast, higher dietary levels of Met did not improve growth performance of the vaccinated chickens. Higher Met levels helped the medicated chickens resist E. tenella infection, as indicated by improved intestinal morphology and immune functions as well as decreased cecal lesion and fecal oocyst counts. CONCLUSIONS: Anticoccidial vaccination is a better strategy for controlling coccidiosis than feeding narasin, due to not only greater growth performance, but also the lower Met supplementation. Furthermore, higher dietary Met levels improved growth performance of chickens medicated rather than vaccinated against coccidia under E. tenella-challenged condition.

Dietary yeast Sterigmatomyces halophilus enhances mucosal immunity of gilthead seabream (Sparus aurata L.).

A yeast was isolated from hypersaline sediments, grown and phylogenetically characterized as Sterigmatomyces halophilus strainN16. The dietary administration of this yeast was studied for its effect on skin mucosal immune and antioxidant status of gilthead seabream (Sparus aurata L.). Fish were fed a commercial diet (control, non-supplemented diet), or the same commercial diet supplemented with 0.55% or 1.1% of yeast for 15 and 30 days. One month after the end of the trial, fish from all treatments were intraperitoneally injected with pathogenic Vibrio parahaemolyticus and further fed with the same diets for one week, after which fish were also sampled. Significant increases were observed in the immune activities determined in the fish fed the yeast supplemented diets compared with the values recorded in mucus of fish from the control group. The expression levels of trypsin (one of the main digestive enzymes) and several immune-related genes (IL-1ß, TNF-α, IgM, C3 and lysozyme) were also evaluated by real-time PCR in intestine and skin. Interestingly, trypsin gene expression in intestine was up regulated in both experimental diets compared with the control group, particularly in fish fed with 0.55% of S. halophilus at any time of the experimental trial. Immune-related genes in intestine and skin were strongly expressed principally in fish fed with 0.55% of S. halophilus for 15 days and 1.1% for 30 days and after infection, respectively. The present results suggest that the yeast S. halophilus can be considered as a novel fish immunostimulant. The excellent potential of marine microorganisms isolated from extreme environments with beneficial properties for fish is discussed.

Dietary ß-glucans differentially modulate immune and stress-related gene expression in lymphoid organs from healthy and Aeromonas hydrophila-infected rainbow trout (Oncorhynchus mykiss).

Although ß-glucans stimulating effects have already been demonstrated on the immune system of numerous animal species, available data remain relatively variable and more research should be done regarding the complexity of underlying mechanisms. In this context, the present study aimed to evaluate the stress and immune-related effects of dietary ß-glucans (i.e. Macrogard®) by considering a number of influencing factors such as the dose (0, 0.1, 0.2 and 0.5% in food), feeding duration (15 versus 30 days), tissue (blood, kidney, spleen, gills) and infection status (healthy or infected). Blood parameters (lysozyme, ACH50 activities, leucocyte populations) and mRNA expression level of several immune- and stress-related genes (TFN-α1, IL-1ß, IL10, COX-2, TGF-ß, MC2R, HSP70) were measured. Our results suggest that spleen may be a highly responsive organ to dietary ß-glucans both in healthy or infected fish, and that this organ may therefore significantly contribute to the immune reinforcement induced by such immunostimulatory diet. Our study further reveals that overdoses of ß-glucans and/or prolonged medication can lead to a non-reactive physiological status and, consequently, to a poor immune response. All in all, the current data emphasizes the need for further extensive research in the field of dietary ß-glucans as a preventive method for farmed fish protection.

Expressão gênica de IGF-I e GHR no fígado e no músculo do peito de codornas de corte suplementadas com diferentes níveis de metionina em duas gerações sucessivas / IGF-I and GHR gene expression in liver and breast muscle of meat quails supplemented with different levels of methionine in two successive generations

Este estudo foi desenvolvido com o objetivo de avaliar a expressão gênica do fator de crescimento semelhante à insulina I (IGF-I) e do receptor do hormônio do crescimento (GHR) no fígado e no músculo do peito de codornas de corte, alimentadas com dietas contendo diferentes níveis de suplementação de metionina, em duas gerações sucessivas. Foram utilizadas codornas dos 22 aos 42 dias de idade, distribuídas em três e cinco tratamentos na primeira e na segunda geração, respectivamente. Ao final, as aves foram abatidas por deslocamento cervical, sendo coletados fígado e músculo do peito para extração de RNA total. O cDNA foi amplificado usando primers específicos para os genes analisados. Os resultados mostraram que a expressão dos genes GHR e IGF-I sofreu influência da suplementação. No quinto tratamento, em que apenas a primeira geração recebeu uma suplementação acima do padrão das exigências para o período, houve uma expressão significativamente maior do GHR tanto no músculo do peito como no fígado e igualmente do IGF-I no músculo, levando a concluir que o excesso de metionina na dieta torna-se tóxica para as aves. Apesar de a expressão dos genes ter sofrido influência da adição de metionina nos níveis estudados, não foi observada diferença no consumo alimentar, na conversão alimentar e no peso das aves.(AU)

This study was conducted to evaluate the gene expression of the insulin-like I growth factor (IGF-I) and growth hormone receptor (GHR), in the liver and chest muscle of slaughter quails fed with diets containing different levels of methionine supplementation, in two successive generations. Twenty-two to 42 day-old quails were used, distributed in three and five treatments in the first and second generation, respectively. At the end, the birds were killed by cervical dislocation, and their liver and chest muscle were collected for total RNA extraction. The cDNA was amplified using specific primers for the genes analyzed. The results showed that the expression of GHR gene and IGF-I were influenced by the supplementation. In the fifth treatment, where only the first generation received supplementation above the standard requirements for the period, there was a significantly higher expression of GHR both in muscle chest and in the liver, and also IGF-I on muscle, leading to the conclusion that the excess dietary methionine becomes toxic to birds. Despite the gene´s expression seeming to be influenced by the addition of methionine levels in the study, there was no difference in feed intake, feed conversion and weight of the birds.(AU)