Shifts in microbiota and gene expression of nutrient transporters, mucin and interleukins in the gut of fast-growing and slow-growing chickens infected by Salmonella Enteritidis.

Slow-growing breeds are more resistant to Salmonella infection compared to fast-growing broilers. However, it is unclear whether that is associated with innate resistance or rather rely on differences in Salmonella-induced gut responses. We investigated the microbial composition and gene expression of nutrient transporters, mucin, and interleukin in the gut of a fast-growing (Cobb500) and a slow-growing naked neck (NN) chicken breeds challenged with Salmonella Enteritidis. Hatchlings were inoculated at two days of age using sterile broth (sham) or Salmonella Enteritidis (SE) and distributed according to a completely randomized design into four treatments: Cobb-sham; Cobb-SE; NN-sham; and NN-SE. Cecal SE counting and microbial composition by 16 S rRNA sequencing were determined at 24-, 96-, and 168-hours post-inoculation (hpi). Gene expression of amino acid (Asct1) and peptide transporters (PepT1), glucose transporters (Sglt1, Glut2 and Glut5) and mucin (Muc2) in the jejunum and expression of interleukins (IL1 beta, IL8, IL17 and IL22) in the cecum was assessed by qPCR at 24 and 168 hpi. NN birds were colonized by SE just as Cobb birds but showed innate upregulation of Muc2, IL8 and IL17 in comparison to Cobb. While nutrient transporter mRNA expression was impaired in SE-challenged Cobb birds, the opposite was observed in NN. There were no differences in microbial diversity at different sampling times for Cobb-SE, whereas the other groups had higher diversity and lower dominance at 24 hpi compared with 96 hpi and 168 hpi. NN birds apparently develop earlier gut microbial stability, have higher basal level of mucin gene expression as well as differential nutrient transporter and interleukin gene expression in the presence of SE which might mitigate the effects of SE infection compared to Cobb birds.

Effects of 25-hydroxycholecalciferol on performance, gut health, and bone quality of broilers fed with reduced calcium and phosphorus diet during Eimeria challenge.

This study evaluated the effects of 25-hydroxycholecalciferol (25-OHD) on performance, gut health, and bone quality of broilers fed with reduced calcium (Ca) and phosphorus (P) diet during Eimeria spp. challenge. A total of 576 fourteen-day-old Cobb 500 male chicks were randomly distributed in a 2 × 2 × 2 factorial arrangement, with 6 replicates of 12 birds each. The main factors were 25-OHD level (0 or 3,000 IU/kg of feed), mineral level (0.84% of Ca/0.42% of P, the levels recommended for the grower phase (NOR) or 0.64% of Ca/0.22% of P (RED), and mid-high mixed Eimeria challenge or nonchallenge. 25-OHD improved phosphorus retention (P = 0.019), bone ash weight (P = 0.04), cortical bone trabecular connectivity (P = 0.043) during coccidiosis. For birds fed with reduced mineral levels, 25-OHD supplementation increased bone ash weight (P = 0.04). However, 25-OHD did not improve bone ash weight when birds were challenged and fed with reduced mineral levels. The dietary 3,000 IU of 25-OHD supplementation did not improve performance or gut morphology but support bone health during coccidiosis. Future investigations are needed for better understand 25-OHD role on bone microarchitecture and oxidative metabolism during coccidiosis.

Deciphering the underlying mechanisms of the oxidative perturbations and impaired meat quality in Wooden breast myopathy by label-free quantitative MS-based proteomics.

The study aimed to investigate biochemical mechanisms occurred in Wooden breast (WB) chicken meat, with attention to the impact on meat quality. Commercial chicken breasts were classified as Normal (N, n = 12), WB-M (moderate degree; focal hardness on cranial region, n = 12) and WB-S (severe degree; extreme and diffused hardness over the entire surface, n = 12). Samples were analyzed for physico-chemical properties, oxidative damage to lipids and proteins, and discriminating sarcoplasmic proteins by using a Q-Exactive mass spectrometer. WB meat presented impaired composition and functionality and higher levels of lipid and protein oxidation markers than N meat. The proteomic profile of WB-S presents a dynamic regulation of the relevant proteins involved in redox homeostasis, carbohydrate, protein and lipid metabolisms. Proteomics results demonstrate that the physiological and metabolic processes of muscles affected by WB myopathy are involved in combating the inflammatory process and in repairing the damaged tissue by oxidative stress.

Eimeria maxima infection impacts the protein utilisation of broiler chicks from 14 to 28 days of age.

In floor-raised broilers, coccidiosis is responsible for reducing the use of nutrients, mainly by impairing intestinal tissue function and activating the immune system. Understanding and quantifying how balanced dietary protein (BP) is used when birds are challenged will allow nutritionists to make decisions regarding challenged flocks. This study aimed to determine the effects of Eimeria maxima on broiler performance and body composition, and to calculate changes in the maintenance and efficiency of protein utilisation (Ep). A total of 2 400 male 14-day-old Cobb500 broiler chickens were randomly allotted to ten groups with six replications of 40 birds each, with a 5 × 2 factorial arrangement of treatments. Five levels of BP in reference to digestible lysine (3.6, 7.2, 10.8, 14.4, and 18.0 g/kg) were fed to unchallenged (NCH) and challenged (CH) broilers with 7 × 103E. maxima sporulated oocysts from 14 to 28 days of age. Performance and body deposition were measured using a comparative slaughter technique to compare BP maintenance requirements and Ep. ANOVA followed by a posthoc test was performed to compare the effects of BP levels, challenge, and their interactions. A monomolecular model describing the responses of NCH and CH broilers to BP intake, maintenance, and maximum protein deposition was compared. There were significant interactions between body weight gain and digestible lysine intake among the factors studied. Infection had a negative impact on all variables analysed, proving the efficacy of the challenge. The maintenance did not differ between the CH and NCH groups. Increased levels of dietary BP did not recover the maximum protein deposition in CH broilers. Eimeria maxima significantly reduced Ep by a factor of 0.09 times on Ep compared to the control group. The Eimeria maxima challenge was responsible to modify the use of BP altering the body composition and impairing broilers performance.

In ovo threonine supplementation affects ileal gene expression of nutrient transporters in broilers inoculated post-hatch with Salmonella Enteritidis.

The effect of in ovo threonine (Thr) supplementation on the ileal expression of glucose, peptide and amino acid transporters was assessed in Salmonella Enteritidis-challenged broiler chicks. At 17.5 days of incubation, fertile eggs were supplemented in the amniotic fluid with sterile saline or 3.5% threonine. Hatchlings were individually weighed, and Salmonella Enteritidis negative status was confirmed. At 2 days of age, half of the birds of each group were inoculated with sterile nutrient broth or Salmonella Enteritidis inoculum. Relative expression of sodium-dependent glucose transporter 1 (SGLT1), glucose transporter 2 (GLUT2), di- and tri-peptide transporter 1 (PepT1) and alanine, serine, cysteine, threonine transporter (ASCT1) was assessed at hatch, 2 and 9 days of age, i.e., before inoculation and 7 days post-inoculation (dpi). At 9 days of age (7dpi), threonine increased SGLT1 and GLUT2 expression, whereas GLUT2 expression decreased in Salmonella-challenged birds. There was a significant interaction between threonine and Salmonella for PepT1 and ASCT1. Threonine increased PepT1 expression only in non-challenged birds. In addition, in ovo supplementation increased expression of ASCT1 regardless of post-hatch inoculation; Salmonella inoculation resulted in decreased expression of ASCT1 only in supplemented birds. The results suggest that while intra-amniotic threonine administration in broiler embryos increases the expression of genes related to the absorption of monosaccharides and amino acids, Salmonella challenge may negatively affect the expression of protein related transporters in the ileum of broilers.

Differentially expressed genes in the femur cartilage transcriptome clarify the understanding of femoral head separation in chickens.

Locomotor problems are among one of the main concerns in the current poultry industry, causing major economic losses and affecting animal welfare. The most common bone anomalies in the femur are dyschondroplasia, femoral head separation (FHS), and bacterial chondronecrosis with osteomyelitis (BCO), also known as femoral head necrosis (FHN). The present study aimed to identify differentially expressed (DE) genes in the articular cartilage (AC) of normal and FHS-affected broilers by RNA-Seq analysis. In the transcriptome analysis, 12,169 genes were expressed in the femur AC. Of those, 107 genes were DE (FDR < 0.05) between normal and affected chickens, of which 9 were downregulated and 98 were upregulated in the affected broilers. In the gene-set enrichment analysis using the DE genes, 79 biological processes (BP) were identified and were grouped into 12 superclusters. The main BP found were involved in the response to biotic stimulus, gas transport, cellular activation, carbohydrate-derived catabolism, multi-organism regulation, immune system, muscle contraction, multi-organism process, cytolysis, leukocytes and cell adhesion. In this study, the first transcriptome analysis of the broilers femur articular cartilage was performed, and a set of candidate genes (AvBD1, AvBD2, ANK1, EPX, ADA, RHAG) that could trigger changes in the broiler´s femoral growth plate was identified. Moreover, these results could be helpful to better understand FHN in chickens and possibly in humans.

Curcumin reduces enteric isoprostane 8-iso-PGF2α and prostaglandin GF2α in specific pathogen-free Leghorn chickens challenged with Eimeria maxima.

The purpose of this pilot study was to evaluate and determine the concentration of prostaglandin GF2α (PGF2α) and isoprostane 8-iso-PGF2α in plasma and intestine of specific pathogen-free (SPF) Leghorn chickens challenged with Eimeria maxima, with or without dietary supplementation of curcumin using solid-phase microextraction and ultra-performance liquid chromatography/tandem mass spectrometry. Eighty 1-day-old male SPF chickens were randomly allocated to one of four groups with four replicates (n = 5 chickens/replicate). Groups consisted of: (1) Control (no challenge), (2) Curcumin (no challenge), (3) Eimeria maxima (challenge), and (4) Eimeria maxima (challenge) + curcumin. At day 28 of age, all chickens in the challenge groups were orally gavaged with 40,000 sporulated E. maxima oocysts. No significant differences (P > 0.05) were observed in the groups regardless of the treatment or challenge with E. maxima. Enteric levels of both isoprostane 8-iso-PGF2α and PGF2α at 7 days and 9 days post-challenge were significantly increased (P < 0.01) compared to the non-challenge control chickens. Interestingly, the enteric levels of both isoprostane 8-iso-PGF2α and PGF2α at 7 days post-challenge were significantly reduced in chickens fed curcumin, compared to control chickens challenge with E. maxima. At 9 days post-challenge, only levels of isoprostane 8-iso-PGF2α in the enteric samples were significantly reduced in chickens challenged with E. maxima supplemented with curcumin, compared with E. maxima challenge chickens. No differences of isoprostane 8-iso-PGF2α or PGF2α were observed in plasma at both days of evaluation. Similarly, no significant differences were observed between the challenge control or chickens challenge with E. maxima and supplemented with curcumin at both times of evaluation. The results of this pilot study suggests that the antioxidant anti-inflammatory properties of curcumin reduced the oxidative damage and subsequent intestinal mucosal over-production of lipid oxidation products. Further studies to confirm and extend these results in broiler chickens are required.

Pinpointing oxidative stress behind the white striping myopathy: depletion of antioxidant defenses, accretion of oxidized proteins and impaired proteostasis.

BACKGROUND: This study aimed to investigate the molecular mechanisms involved in the onset of the white striping (WS) myopathy with particular attention to the role of oxidative stress and protein oxidation in the loss of meat quality. RESULTS: It was found that WS-M (moderate degree; white stripes <1 mm thickness) and WS-S (severe degree; white stripes >1 mm thickness) breast presented higher pH, hardness, redness, lipid, and collagen content, and lower lightness than normal breast. Compared with the latter, WS-S had a more severe loss of protein thiols (70.7% less thiols than in N), reduced activity of antioxidant enzymes such as catalase (23 versus 40 U g-1 ), glutathione peroxidase (0.21 versus 0.54 U g-1 ), and superoxide dismutase (56 versus 73 U g-1 ), and consequently, had greater accretion of thiobarbituric acid reactive substances (0.64 versus 0.22 mg MDAkg-1 muscle), allysine (3.1 versus 1.9 nmol mg-1 protein) and Schiff base structures (645 versus 258 fluorescent units). The analysis of sarcoplasmic proteins revealed that muscles severely affected by the myopathy suffered a chronic impairment of physiological (upregulation of sarcoplasmic reticulum Ca2+ ATPase, sarcalumenin and calsequestrin-2) and metabolic processes (downregulation of pyruvate kinase, creatine kinase, and l-lactate dehydrogenase). CONCLUSION: The overexpression of ribonuclease / angiogenin inhibitor 1 and Kelch-like proteins in WS chicken breasts indicates altered protein turnover plausibly mediated by oxidative stress and accumulation of oxidized proteins. © 2020 Society of Chemical Industry.

Fumonisin-(Fusarium verticillioides)-contaminated feed causes hepatic oxidative stress and negatively affects broiler performance in the early stage: Does supplementation with açai flour residues (Euterpe oleracea) minimize these problems?

Fusarium verticillioides is often responsible for contamination of poultry feed with the mycotoxin fumonisin. The aim of this study was to determine whether oxidative stress caused by intake of fumonisin-contaminated feed affects broiler performance at an early stage of development, as well as to test whether the addition of açai residue flour to contaminated feed would minimize these negative effects of redox metabolism. Birds were divided into four groups, with four repetitions of five animals each: control (TC) - birds that received basal feed; TCA treatment - basal feed supplemented with 2% açai flour; TF treatment - feed experimentally contaminated with fumonisin (10 ppm); TFA treatment - fumonisin-contaminated feed (10 ppm) and supplemented with açai fluor (2%). The experiment lasted 20 days, that is, the first 20 days of the chicks' lives. At the end of the experiment, the birds were weighed, and blood, intestine and liver samples were collected. The TCA and TFA had greater body weights and weight gain than did TF. Further, TCA and TFA had lower feed conversion than did TF. Açai flour intake (TCA and TFA) stimulated albumin synthesis and reduced serum AST activity. Nitrate/nitrite (NOx) levels were higher in serum of fumonisin-challenged (TF) birds than in groups; NOx levels were also higher in the livers of all test groups (TF, TCA and TFA) than in TC. Serum glutathione S-transferase (GST) activity was lower in fumonisin-consuming groups (TF and TFA); this was different from what occurred in the liver, that is, higher GST activity in TF and lower activity in TFA than in TC. Catalase activity (CAT) was also higher in the fumonisin-challenged groups (TF and TFA) and the groups supplemented with açai flour (TCA) than in TC. Serum reactive species (RS) and TBARS (lipid peroxidation) levels in the liver were lower in birds supplemented with açai flour and exposed to fumonisin. These data suggest that the addition of açai flour in the feed of early chickens improves animal performance and minimizes the effects of hepatic oxidative stress in birds fed fumonisin-contaminated feed.

Stable reference genes for expression studies in breast muscle of normal and white striping-affected chickens.

The normalization with proper reference genes is a crucial step to obtain accurate mRNA expression levels in quantitative PCR (qPCR) studies. Therefore, in this study, 10 reference candidate genes were evaluated to determine their stability in normal pectoralis major muscle of broilers and those counterparts affected with White Striping (WS) myopathy at 42 days age. Four different tools were used for ranking the most stable genes: GeNorm, NormFinder, BestKeeper and Comparative Ct (ΔCt), and a general ranking was performed using the RankAggreg tool to select the best reference genes among all tools. From the 10 genes evaluated in the breast muscle of broilers, 8 were amplified. Most of the algorithms/tools indicated the same two genes, RPL30 and RPL5, as the most stable in the broilers breast muscle. In addition, there was agreement among the tools for the least stable genes: MRPS27, GAPDH and RPLP1 in the broilers breast muscle. Therefore, it is interesting to note that even with different tools for evaluating gene expression, there was consensus on the most and least stable genes. These results indicate that the Ribosomal protein L30 (RPL30) and Ribosomal protein L5 (RPL5) can be recommended for accurate normalization in qPCR studies with chicken pectoralis major muscle affected with White Striping and other myopathies.

Impacts of Escherichia coli infection in young breeder chicks on the animal behavior and cerebral activity of purinergic and cholinergic enzymes involved in the regulation of molecules with neurotransmitter and neuromodulator function.

The objective of this study was to evaluate if infection by Escherichia coli in juvenile breeder chicks alters the activity of enzymes involved in neurotransmission and cerebral immunomodulation, including acetylcholinesterase (AChE), nucleoside triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase (5'NT) and adenosine deaminase (ADA), as well as their effects on the pathogenesis of the disease. We divided 20 growing breeder chicks into two groups (n = 10 per group). One group was experimentally infected with 1 mL of culture medium containing 1 × 108 CFU of E. coli intraperitoneally. The other was the negative control. On the tenth day after infection, the animals were euthanized and brain samples were collected. Macroscopically, pericarditis and hepatic congestion were observed in the birds, but without histopathological lesions in the encephalon although the bacterium was present in the cerebral cortex of all animals in the infected group (i.e., they were PCR-positive). The activity of AChE, NTPDase, 5'-NT and ADA were evaluated in the cerebral homogenates of the birds after 10 days of infection. AChE activity in the cerebral cortex was lower in the infected group than in the control; there was an increase in the activity of NTPDase, 5'-nucleotidase and ADA, possibly indicating greater hydrolysis of ATP (P < 0.001), ADP (P < 0.01) and AMP (P < 0.01), followed by increased adenosine deamination (P < 0.001). Despite these changes, no apparently diseased animals were observed throughout the experimental period. Therefore, such changes in enzymatic activity may affect the functioning of the central nervous system because these enzymes are responsible for extracellular regulation of molecules that act on neurotransmission and immunomodulation such as acetylcholine, ATP and adenosine.

Combination of herbal components (curcumin, carvacrol, thymol, cinnamaldehyde) in broiler chicken feed: Impacts on response parameters, performance, fatty acid profiles, meat quality and control of coccidia and bacteria.

The objective of this study was to determine whether curcumin and a commercial microencapsulated phytogenic supplement containing thymol, cinnamaldehyde and carvacrol in broiler chicken feed would improve health and meat quality (fatty acid profile), as well as to determine the coccidiostatic and bactericidal potential of the additives. The broiler chickens were divided into five groups: NC - negative control feed; PC - positive control; CU - with 50 mg/kg of curcumin, PHY - 100 mg/kg phytogenic; and PHY + CU, a combination of both additives at 50 mg/kg (curcumin) and 100 mg/kg (phytogenic). We observed significantly higher levels of total proteins associated with increased circulating globulins, as well as lower levels of uric acid, cholesterol and triglycerides in the PHY + CU group than in the NC. There were significantly fewer oocysts in birds supplemented with additives in the NC group on day 21; on day 35, the NC, PHY and PHY + CU groups had significantly lower counts than the PC and CU groups; however, at 44 days, the lowest counts were in PC group. The bacterial counts were significantly lower on day 21 in all groups that received additives than those of the control group; however, at 44 days, the bacterial and Escherichia coli counts in these groups were significantly higher than those of the control. Curcumin with or without phytogenic agent improved meat quality, with increased antioxidant levels and reduction of lipid peroxidation. There were significantly lower total saturated fatty acid levels and significantly greater monounsaturated/polyunsaturated fatty acid levels in broilers that consumed additives individually and in combination. The combination of additives significantly increased the crypt/villus ratio, a marker of improved intestinal health and performance. Additives potentiated their individual effects, suggesting they can replace conventional growth promoters without compromising health, intestinal mucosa or meat quality.

Impact of Escherichia coli infection in broiler breeder chicks: The effect of oxidative stress on weight gain.

The aim of this study was to determine whether oxidative stress occurs in Escherichia coli-infected broiler breeder chicks, as well as the impact of this infection on bird growth. Twenty birds, 25-day-old female birds were divided into two groups (n = 10 per group): an intraperitoneally-infected group (1 mL containing 1.5 × 108 CFU of E. coli) and a control group that received 1 mL of culture medium (uninfected birds). Birds were weighed individually at the beginning and at the end of the experiment, and samples were collected on days 0, 5 and 10 post-infection (PI). No clinical signs were observed throughout the experimental period; nevertheless, on day 10 PI, there was lower growth and weight gain in infected birds than in the control group. The infected birds showed pericarditis and liver congestion, as well as moderate periportal inflammatory infiltrates with predominance of neutrophils. Significantly higher numbers of total leukocytes, lymphocytes, heterophils and monocytes were observed in the infected group on days 5 and 10 PI, as well as significantly higher total protein and globulin levels; albumin values significantly decreased over the same period. Levels of serum oxidative biomarkers (lipid peroxidation (TBARS) and free radicals (ROS)) were significantly higher at 10 PI, as was glutathione S-transferase (GST) activity during the same period. Hepatic ROS and protein thiol levels were significantly higher in E. coli-infected birds, as well as activities of the antioxidant enzymes catalase, superoxide dismutase. In the spleen, only GST activity was significantly higher for the infected group, unlike the brain, where SOD activity, ROS and non-protein thiol levels were significantly higher in infected birds than in the control group. These data suggested that colibacillosis causes oxidative stress in broiler breeder chicks, negatively affecting their weight gain.

Dietary supplementation with free methionine or methionine dipeptide improves environment intestinal of broilers challenged with Eimeria spp.

This study examined the influence of a diet enriched with free methionine (dl-Met) or methionine dipeptide (dl-MMet) on the intestinal health of Eimeria-challenged (EC) and unchallenged (UC) broilers. A non-supplemented, methionine-deficient diet (NS) was used as control. Treatments were arranged in a 2 × 3 factorial completely randomized design with eight replications. Broilers in the EC group were infected with sporulated oocysts of Eimeria spp. (E. acervulina, E. maxima, E. praecox, and E. mitis) at 14 d of age. Performance analysis, light and electron microscopy of the jejunum, analysis of genes related to apoptosis and cell proliferation in the jejunum, and blood tests were performed at 6 days post-inoculation (dpi). EC broilers had poorer performance than UC broilers, regardless of diet (P < 0.001). Broilers fed the dl-Met diet had greater weight gain (P = 0.004) and lower feed conversion ratio (P = 0.019) than broilers fed other diets. Jejunal sections from EC broilers fed the NS diet showed short (P = 0.001) and wide villi (P < 0.001) with increased crypt depth (P < 0.001) and reduced villus / crypt ratio (P = 0.001), jejunal absorptive surface area (P < 0.001), number of neutral goblet cells (Eimeria challenge: P = 0.048; diet P = 0.016), and mucin 2 (MUC2) gene expression (P = 0.018). EC birds fed the dl-MMet diet had higher enterocyte height (P < 0.001). Birds fed the dl-MMet diet had low lamina propria width (P = 0.009). UC broilers fed the dl-Met diet had the highest number of acidic goblet cells (P = 0.005), whereas EC broilers assigned the dl-MMet diet showed the highest number of intraepithelial lymphocytes (P = 0.033). Reduced expression of caspase-3 (CASP3) (P = 0.005), B-cell lymphoma 2 (BCL2) (P < 0.001), mechanistic target of rapamycin (MTOR) (P < 0.001), and ribosomal protein S6 kinase B1 (RPS6KB1) (P < 0.001) genes was observed in EC animals. MTOR expression levels were highest in birds fed the dl-MMet diet (P = 0.004). Plasma activities of aspartate aminotransferase (AST) was influenced by both diet (P = 0.002) and Eimeria challenge (P = 0.005), with EC broilers assigned the NS diet showing the highest levels. EC broilers fed the NS diet had higher creatine kinase (CK) activity (P = 0.049). EC broilers had lower plasma uric acid (P = 0.004) and higher serum mucoproteins level (P < 0.001). These results indicate that methionine dipeptide supplementation is able to mitigate the harmful intestinal effects of Eimeria spp. in broilers.

Cytokine gene transcription in the trachea, Harderian gland, and trigeminal ganglia of chickens inoculated with virulent infectious laryngotracheitis virus (ILTV) strain.

The objective of this study was to determine how cytokine transcription profiles correlate with patterns of infectious laryngotracheitis virus (ILTV) replication in the trachea, Harderian gland, and trigeminal ganglia during the early and late stages of infection after intratracheal inoculation. Viral genomes and transcripts were detected in the trachea and Harderian gland but not in trigeminal ganglia. The onset of viral replication in the trachea was detected at day one post-infection and peaked by day three post-infection. The peak of pro-inflammatory (CXCLi2, IL-1ß, IFN-γ) and anti-inflammatory (IL-13, IL-10) cytokine gene transcription, 5 days post-infection, coincided with the increased recruitment of inflammatory cells, extensive tissue damage, and limiting of virus replication in the trachea. In contrast, transcription of the IFN-ß gene in the trachea remained unaffected suggesting that ILTV infection blocks type I interferon responses. In the Harderian gland, the most evident transcription change was the early and transient upregulation of the IFN-γ gene at 1 day post-infection, which suggests that the Harderian gland is prepared to rapidly respond to ILTV infection. Overall, results from this study suggest that regulation of Th1 effector cells and macrophage activity by Th1/2 cytokines was pertinent to maintain a balanced immune response capable of providing an adequate Th1-mediated protective immunity, while sustaining some immune homeostasis in preparation for the regeneration of the tracheal mucosa.

Pandemic extra-intestinal pathogenic Escherichia coli (ExPEC) clonal group O6-B2-ST73 as a cause of avian colibacillosis in Brazil.

Extra-intestinal pathogenic Escherichia coli (ExPEC) represent an emerging pathogen, with pandemic strains increasingly involved in cases of urinary tract infections (UTIs), bacteremia, and meningitis. In addition to affecting humans, the avian pathotype of ExPEC, avian pathogenic E. coli (APEC), causes severe economic losses to the poultry industry. Several studies have revealed overlapping characteristics between APEC and human ExPEC, leading to the hypothesis of a zoonotic potential of poultry strains. However, the description of certain important pandemic clones, such as Sequence Type 73 (ST73), has not been reported in food sources. We characterized 27 temporally matched APEC strains from diverse poultry farms in Brazil belonging to the O6 serogroup because this serogroup is frequently described as a causal factor in UTI and septicemia in humans in Brazil and worldwide. The isolates were genotypically characterized by identifying ExPEC virulence factors, phylogenetically tested by phylogrouping and multilocus sequence type (MLST) analysis, and compared to determine their similarity employing the pulsed field gel electrophoresis (PFGE) technique. The strains harbored a large number of virulence determinants that are commonly described in uropathogenic E. coli (UPEC) and sepsis associated E. coli (SEPEC) strains and, to a lesser extent in neonatal meningitis associated E. coli (NMEC), such as pap (85%), sfa (100%), usp (100%), cnf1 (22%), kpsMTII (66%), hlyA (52%), and ibeA (4%). These isolates also yielded a low prevalence of some genes that are frequently described in APEC, such as iss (37%), tsh, ompT, and hlyF (8% each), and cvi/cva (0%). All strains were classified as part of the B2 phylogroup and sequence type 73 (ST73), with a cluster of 25 strains showing a clonal profile by PFGE. These results further suggest the zoonotic potential of some APEC clonal lineages and their possible role in the epidemiology of human ExPEC, in addition to providing the first description of the O6-B2-ST73 clonal group in poultry.

Age-related oxidative stress and antioxidant capacity in heat-stressed broilers.

We aimed to evaluate the effects of acute heat stress (HS) and age on the redox state in broilers aged 21 and 42 days. We evaluated the expression of genes related to antioxidant capacity, the production of hydrogen peroxide (H2O2), and the activity of antioxidant enzymes in the liver, as well as oxidative stress markers in the liver and plasma. The experiment had a completely randomized factorial design with two thermal environments (thermoneutral and HS, 38°C for 24 h) and two ages (21 and 42 days). Twenty-one-day-old animals exposed to HS showed the highest thioredoxin reductase 1 (TrxR1) (P<0.0001) and glutathione synthetase (GSS) (P<0.0001) gene expression levels. Age influenced the expression of the thioredoxin (Trx) (P=0.0090), superoxide dismutase (SOD) (P=0.0194), glutathione reductase (GSR) (P<0.0001) and glutathione peroxidase 7 (GPx7) (P<0.0001) genes; we observed greater expression in birds at 21 days than at 42 days. Forty-two-day-old HS birds showed the highest H2O2 production (222.31 pmol dichlorofluorescein produced/min×mg mitochondrial protein). We also verified the effects of age and environment on the liver content of Glutathione (GSH) (P<0.0001 and P=0.0039, respectively) and catalase (CAT) enzyme activity (P=0.0007 and P=0.0004, respectively). Higher GSH content and lower CAT activity were observed in animals from the thermoneutral environment compared with the HS environment and in animals at 21 days compared with 42 days. Broilers at 42 days of age had higher plasma creatinine content (0.05 v. 0.01 mg/dl) and higher aspartate aminotransferase activity (546.50 v. 230.67 U/l) than chickens at 21 days of age. Our results suggest that under HS conditions, in which there is higher H2O2 production, 21-day-old broilers have greater antioxidant capacity than 42-day-old animals.

Fowl typhoid in laying hens cause hepatic oxidative stress.

The aim of this study was to analyses nitric oxide, antioxidant status, and oxidative profile in the liver of laying hens naturally infected by Salmonella enterica subsp enterica serovar Gallinarum (S. Gallinarum). The nitrite/nitrate (NOx), reactive oxygen species (ROS), thiobarbituric acid-reactive substances (TBARS), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities were measured in liver samples, as well the biomarkers of hepatic function (alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total protein and albumin levels measured in serum. NOx levels and CAT activity were reduced in hepatic tissue of infected hens. On the other hand, TBARS and ROS levels, GR, GPx and GST activities were higher in infected animals. On biomarkers of tissue damage, ALT, AST, GGT and total protein levels were higher in serum of infected hens, and showed decreased albumin levels. In summary, ROS and TBARS production lead to damage on the membrane lipids that alter activities of antioxidant enzymes CAT, GR, GPx and GSH, an adaptive response against S. Gallinarum infection, contributing to the pathophysiology and clinical signs of the disease.

Metabolic alterations in broiler chickens experimentally infected with sporulated oocysts of Eimeria maxima.

Metabolic and morphometric alterations of the duodenal villi caused by parasitism of chickens by Eimeria maxima were evaluated, using 100 male Cobb birds, randomly distributed into two groups (control and infected). The infected group was inoculated with 0.5 ml of a solution containing 5 × 10³ sporulated oocysts of Eimeria maxima. Ten birds per sample were sacrificed on the 6th, 11th, 22nd and 41st days post-infection (dpi). In order to evaluate the alterations, samples of duodenum, jejunum and ileum fragments were collected after necropsy for histological analysis. Villus biometry was determined by means of a slide graduated in microns that was attached to a binocular microscope. To evaluate the biochemical data, 5 ml of blood were sampled from the birds before sacrifice. The statistical analyses were performed using the GraphPad 5 statistical software for Windows. Tukey's multiple comparison test (p <0.05) was performed for the different dpi's and the unpaired t test for the difference between the groups. Infection by E. maxima causes both qualitative and quantitative alterations to the structure of the intestinal villi, thereby interfering with the absorption of nutrients such as calcium, phosphorus, magnesium, protein and lipids, with consequent reductions in the birds' weights.

Metabolic alterations in broiler chickens experimentally infected with sporulated oocysts of Eimeria maxima / Alterações metabólicas em frangos de corte infectados experimentalmente com oocistos esporulados de Eimeria maxima

Metabolic and morphometric alterations of the duodenal villi caused by parasitism of chickens by Eimeria maxima were evaluated, using 100 male Cobb birds, randomly distributed into two groups (control and infected). The infected group was inoculated with 0.5 ml of a solution containing 5×103 sporulated oocysts of Eimeria maxima. Ten birds per sample were sacrificed on the 6th, 11th, 22nd and 41st days post-infection (dpi). In order to evaluate the alterations, samples of duodenum, jejunum and ileum fragments were collected after necropsy for histological analysis. Villus biometry was determined by means of a slide graduated in microns that was attached to a binocular microscope. To evaluate the biochemical data, 5 ml of blood were sampled from the birds before sacrifice. The statistical analyses were performed using the GraphPad 5 statistical software for Windows. Tukey's multiple comparison test (p <0.05) was performed for the different dpi's and the unpaired t test for the difference between the groups. Infection by E. maxima causes both qualitative and quantitative alterations to the structure of the intestinal villi, thereby interfering with the absorption of nutrients such as calcium, phosphorus, magnesium, protein and lipids, with consequent reductions in the birds' weights.

Foram avaliadas alterações metabólicas e morfométricas das vilosidades intestinais causadas pelo parasitismo de frangos por Eimeria maxima, sendo utilizadas 100 aves da linhagem Coob, machos, distribuídos aleatoriamente em dois grupos experimentais: grupo controle, inoculado com 0,5 ml de água destilada; grupo infectado, inoculado com 0,5ml de solução contendo 5×103 oocistos esporulados de Eimeria maxima. Foram sacrificadas 10 aves por coleta no 0, 6, 11, 22 e 41 dias pós-infecção. Para avaliar as alterações foram retiradas, após necropsia, amostras de fragmentos do duodeno, jejuno e íleo para análise histológica. A determinação da biometria de vilosidades foi realizada por meio de lâmina milimetrada acoplada a um microscópio binocular. Para avaliação dos dados bioquímicos foram coletados 5 ml de sangue das aves antes da eutanásia. As análises estatísticas foram realizadas, utilizando-se o programa estatístico Graphpad Prism. 5 – Windows e realizado o teste de comparações múltiplas de Tukey (p <0,05) para os diferentes dpi's e o Teste T não Pareado para diferença entre os grupos. A infecção por E. maxima provoca alterações qualitativas e quantitativas das vilosidades intestinais, interferindo na absorção de nutrientes, como cálcio, fósforo, magnésio, proteínas e lipídios, com consequente redução no peso das aves.