Non-challenged Control Research Articles

Dietary tryptophan supplementation enhances mitochondrial function and reduces pyroptosis in the spleen and thymus of piglets after lipopolysaccharide challenge.

The thymus and spleen, the main reservoirs for T lymphocytes, modulate the innate immune response. Oxidative stress, excessive inflammation and abnormal pyroptosis can cause dysfunction of these organs. This study aimed to examine whether tryptophan supplementation can improve growth performance and mitochondrial function via the adenosine 5'-monophosphate-activated protein kinase (AMPK)/sirtuin1 (Sirt1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) signalling pathway and decrease pyroptosis via the nucleotidebinding oligomerisation domain-like receptor protein 3 (NLRP3)/caspase-1/gasderminD (GSDMD) signalling pathway in the spleen and thymus of piglets after lipopolysaccharide (LPS) challenge. Eighteen weaned piglets were allotted to three treatment groups: non-challenged control, LPS-challenged control and LPS+0.2% tryptophan. On day 35, the pigs in the LPS and LPS+0.2% tryptophan groups were injected with 100μg/kg BW LPS, whereas those in the control group were administered with sterile saline. At 4h postchallenge, the weaned piglets were sacrificed, and their thymuses and spleens were collected. Results showed that tryptophan enhanced growth performance and antioxidant status by increasing catalase, glutathione peroxidase and total superoxide dismutase activities and decreasing malondialdehyde and reactive oxygen species contents. Tryptophan also reduced the mRNA levels of proinflammatory cytokine genes and enhanced mitochondrial function by increasing the mRNA levels of mitochondrial transcription factor A, nuclear respiratory factor-1, mitochondria transcription factor B1, AMPKα1, AMPKα2, Sirt1 and PGC1α and the protein expression of phosphorylated AMPK, Sirt1 and PGC1α. It also reduced pyroptosis by decreasing the mRNA levels of NLRP3, apoptosis-associated speck-like protein containing CARD, caspase-1 and GSDMD and the protein expression of NLRP3, caspase-1 and GSDMD. These results indicate that tryptophan supplementation enhances growth performance and mitochondrial function via the AMPK/Sirt1/PGC1α signalling pathway and decreases pyroptosis via the NLRP3/caspase-1/GSDMD signalling pathway in the spleen and thymus of LPS-challenged piglets.

Evaluation of the impact of formaldehyde fumigation during the hatching phase on contamination in the hatch cabinet and early performance in broiler chickens

Commercial hatch cabinet environments promote replication of microorganisms. These pathogenic or apathogenic microorganisms may serve as pioneer colonizers of the gastrointestinal tract (GIT) of poultry. Some of these pioneer colonizers, such as Escherichia coli and Enterococcus spp., are opportunistic pathogens that lead to reduced performance in commercial poultry. Effective hatchery sanitation is imperative to limit contamination of naïve neonatal chicks and poults. Formaldehyde fumigation has been traditionally used to reduce the pathogen load in commercial hatch cabinets. To investigate potential alternatives to formaldehyde fumigation, models to mimic the microbial bloom in a laboratory setting must be utilized. The purpose of the present study was to evaluate the impact of a multispecies environmental challenge model (PM challenge) with and without formaldehyde fumigation during the hatching phase on early performance in broiler chicks. Three experiments were conducted to evaluate microbial contamination in the hatch cabinet environment (air samples, fluff samples), enteric colonization at day-of-hatch (DOH), and 7-day performance. In all experiments, significantly (P < 0.05) more gram-negative bacteria were recovered from the GIT at DOH in the PM challenge control group as compared to the nonchallenged control (NC) group and the formaldehyde-treated group (PM+F). There were no statistical differences in 7-day body weight gain or feed conversion ratio between the PM challenge control group, the NC group or the PM+F group. These data suggest this model could be utilized to evaluate alternatives to formaldehyde fumigation for controlling the microbial load during the hatching phase in a laboratory setting.

Effects of a pre- and probiotic mixture and an autogenous vaccine on growth performance in newly weaned piglets experimentally challenged with an enterotoxigenic Escherichia coli strain.

Beneficial effects of pro- and prebiotics in weanling piglets are of great interest in livestock production. Similarly, the use of specific vaccines is of interest as alternative to antibiotics to reduce postweaning performance losses. The aim of this study was the assessment of the effect of a dual-strain probiotic (Bacillus subtilis and Bacillus licheniformis) and a prebiotic (fructo-oligosaccharides) as well as the additional vaccination with an autogenous inactivated Escherichia coli vaccine on the performance of newly weaned piglets after experimental infection with an enterotoxigenic E. coli. Forty piglets at the age of 28 d were randomly allotted to one of five groups: nonchallenged control (NC); challenged positive control (PC); challenged and vaccinated (CV); challenged and diet supplemented with pre- and probiotic mix (CM) and challenged, diet supplemented with pro- and prebiotic mix and vaccinated (CMV). Piglets of CV and CMV were vaccinated parenterally prior to the trial at the age of 17 d. Compared to NC, the experimental infection with E. coli resulted in a significant reduction of body weight gain in both vaccinated groups (P = 0.045), which was associated with an impaired gain to feed ratio (P = 0.012), but not feed intake. In contrast, piglets in the group supplemented with pro- and prebiotics (group CM) were able to maintain their weight and had an average daily gain, which was not significantly different from groups NC and PC. No differences regarding body weight gain, feed intake, gain to feed ratio and fecal score were observed between groups during the 3rd and 4th week of the trial. A significant impairment of fecal consistency and frequency of diarrhea was observed related to the oral challenge when comparing PC and NC treatments (P = 0.024). Neither vaccine, nor supplementation with pro- and prebiotics were able to significantly improve fecal consistency, nor did they have a positive effect on the prevalence of diarrhea. The results show no positive synergistic effect of the specific combination of vaccine and pre- and probiotics used in this trial on performance and diarrhea. The results show that the concept of a combination of a specific vaccination and a probiotic with a prebiotic needs further investigation. In the sense of avoiding the use of antibiotics, this seems to be an attractive approach.

Characterization of Two Porcine Parainfluenza Virus 1 Isolates and Human Parainfluenza Virus 1 Infection in Weaned Nursery Pigs

Porcine parainfluenza virus 1 (PPIV1) is a newly characterized porcine respiratory virus. Recent experimental challenge studies in three-week-old nursery pigs failed to cause disease. However, it remains unclear how genetic differences contribute to viral pathogenesis. To characterize the pathogenesis of different PPIV1 isolates, three-week-old nursery pigs were challenged with either PPIV1 isolate USA/MN25890NS/2016 (MN16) or USA/IA84915LG/2017 (IA17). A human parainfluenza virus 1 (HPIV1) strain C35 ATCC® VR-94™ was included to evaluate swine as a model for human parainfluenza. All viruses were successfully re-isolated from bronchoalveolar lavage fluid and detected by RT-qPCR at necropsy. Microscopic lung lesions were more severe in the IA17 group compared to the non-challenged negative control (Ctrl) group whereas differences were not found between the MN16 and Ctrl groups. Immunohistochemistry staining in respiratory samples showed a consistent trend of higher levels of PPIV1 signal in the IA17 group followed by the MN16 group, and no PPIV1 signal observed in the HPIV1 or Ctrl groups. This study suggests potential pathogenesis differences between PPIV1 isolates. Additionally, these results indicate that HPIV1 is capable of replicating in nursery pigs after experimental inoculation. However, clinical disease or gross lung lesions were not observed in any of the challenge groups.

Protective Efficacy of Inactivated H9N2 Vaccine in Turkey Poults under Both Experimental and Field Conditions.

Low pathogenic avian influenza (LPAI) H9N2 virus is one of the major poultry pathogens associated with severe economic losses in the poultry industry (broiler, layers, breeders, and grandparents' flocks), especially in endemic regions including the Middle East, North Africa, and Asian countries. This work is an attempt to evaluate the efficacy of whole inactivated H9N2 vaccine (MEFLUVACTM H9) in turkey poults kept under laboratory and commercial farm conditions. Here, 10,000 white turkey poults (1-day old) free from maternally derived immunity against H9N2 virus were divided into four groups; G1 involved 10 vaccinated birds kept under biosafety level-3 (BLS-3) as a laboratory vaccinated and challenged group, while G2 had 9970 vaccinated turkeys raised on a commercial farm. Ten of those birds were moved to BLS-3 for daily cloacal and tracheal swabbing to check for the absence of any life-threating disease, before conducting analyses. G3 (10 birds) served as a non-vaccinated challenged control under BSL-3 conditions, while G4 (10 birds) was used as a non-vaccinated and non-challenged control under BSL-3 conditions. Sera were collected on days 7-, 14-, 21-, and 28-post-vaccinations to monitor the humoral immune response using a hemagglutination-inhibition (HI) test. At these same intervals, cloacal and tracheal swabs were also checked for any viral infection. The challenge was conducted 28 days post-vaccination (PV) using AI-H9N2 in BSL-3 by intranasal inoculation of 6-log10 embryo infective dose50 (EID50). At 3-, 6-, and 10-days post-challenge, oropharyngeal swabs were taken from challenged birds to quantify viral shedding by quantitative polymerase chain reaction (qRT-PCR). The results of this study showed that vaccinated groups (G1/2) developed HI titers of 1.38, 4.38, 5.88, and 7.25 log2 in G1 vs. 1.2, 3.8, 4.9 and 6.2 log2 in G2 when measured at 7-, 14-, 21- and 28-days PV, respectively, while undetectable levels were recorded in non-vaccinated groups (G3/4). Birds in G3 showed 90% clinical sickness vs. 10% and 20% in G1/2, respectively, over a 10-day monitoring period following challenge. Vaccinated birds showed a significant reduction in virus shedding in terms of the number of shedders, amount of shed virus and shedding interval over the non-vaccinated challenged birds. Regarding mortality, all groups did not show any mortality, which confirms that the circulating H9N2 virus still has low pathogenicity and cannot cause mortality. However, the virus may cause up to 90% clinical sickness in non-vaccinated birds vs. 10% and 20% in laboratory- and farm-vaccinated birds, respectively, highlighting the role of the vaccine in limiting clinical sickness cases. In conclusion, under the current trial circumstances, MEFLUVACTM-H9 provided protective seroconversion titers, significant clinical sickness protection and significant reduction in virus shedding either in laboratory- or farm-vaccinated groups after a single vaccine dose.

Tryptophan alleviates lipopolysaccharide-induced muscle fiber type transformation from type I to II and modulates Sirt1/AMPK/PGC-1α signaling pathway in pigs

Tryptophan is a functional amino acid. This study aimed to investigate whether dietary tryptophan supplementation can alleviate Escherichia coli lipopolysaccharide (LPS)-induced skeletal muscle fiber transition from type I to type II in pigs, and the molecular mechanism was also examined. Eighteen weaned piglets were allotted to three treatments groups, namely, the nonchallenged control, LPS-challenged control and LPS + 0.2% tryptophan groups. On day 35, the pigs in the LPS and LPS + 0.2% tryptophan groups were challenged by injection with 100 μg/kg body weight (BW) LPS, whereas the control group was given sterile saline. Tryptophan can attenuate LPS-induced decrease in protein content of slow MyHC, the activities of succinic dehydrogenase, malate dehydrogenase (MDH) and antioxidant enzyme, the mRNA expression of oxidative muscle fiber-related genes, type I fiber proportion, and increase in lactate dehydrogenase (LDH) activity, the mRNA expression level of MyHC IIb and type II fiber proportion. Moreover, tryptophan supplementation attenuated LPS-induced decrease in the expression levels of phosphorylated AMP-activated protein kinase (AMPK), silent information regulator 1 (Sirt1) and peroxisome proliferator activated receptor gamma coactivator 1-alpha (PGC-1α). Collectively, tryptophan can alleviate LPS-induced muscle fiber type transformation from type I to type II. This effect is associated with activating the Sirt1/AMPK/PGC-1α signaling pathway.

PSX-B-14 Effects of Adding Protected Benzoic Acid on Growth Performance, Diarrhea, and Inflammation in Weaned Pigs Challenged with Escherichia Coli F18

Abstract This experiment quantified the impact of an E. coli challenge and evaluated protected benzoic acid (PBA) as the alternative to recover growth performance, diarrhea, and inflammation of weaned pigs. A total of 72 pigs (BW=6.07±0.66kg) were housed in pens (2 pigs/pen) and randomly assigned to 1 of 3 treatments (12 pens/treatment). Treatments included a non-challenged control (NC), a challenged-control experimentally infected with F18 E. coli (PC), and PC plus 0.25% PBA (Novus international St. Charles, MO). The experiment lasted 18 days, with 7 days of acclimation and 11 days post-infection (dpi). Blood samples were collected at 0, 4, and 11 dpi. Data were analyzed using the MIXED procedure of SAS. At the end of the experiment (11 dpi), pigs on NC were heavier than those in the PC, whereas pigs fed PBA were intermediate (9.43, 8.22, and 8.75kg, respectively; P = 0.026). For the entire experimental period (-7 to 11 dpi) pigs on the NC had increased ADG compared with PC and PBA (0.196, 0.105, and 0.127kg, respectively; P=0.019). Pigs on the NC had increased ADFI compared with PC, whereas PBA was intermediate (0.244, 0.167, and 0.204kg, respectively; P=0.011). G:F tended to differ among treatments (P=0.070): the NC had the greatest G:F followed by PBA and NC (0.800, 0.565, 0507, respectively). Diarrhea incidence was decreased in the NC compared with PC and PBA (22.9, 44.2, and 52.1%, respectively; P=0.01). Serum acute-phase C reactive protein (CRP), a marker of systemic inflammation, tended to differ among treatments (P=0.076): the PC had the greatest CRP concentration followed by PBA and NC (3,841, 2,243, and 2,106 ng/mL, respectively). In conclusion, the E. coli infection impacted the growth and health of weaned pigs; however, the addition of PBA partially alleviated the negative effects by stimulating feed intake, growth, and decreasing systemic inflammation.

Serum-isolated exosomes from Piscirickettsia salmonis-infected Salmo salar specimens enclose bacterial DnaK, DnaJ and GrpE chaperones

BackgroundEndosomally produced by eukaryotic cells, exosomes are microvesicles involved in cell-to-cell communication. Exosomes have shown a wide range of therapeutic potential as a drug or vaccine delivery system, and they are useful as biomarkers in several disease processes. Another biological function described is pathogen dissemination through host-derived molecules released during infection, thus modulating the immune response in the host. ResultsThis work characterizes the exosomal fraction recovered from serum of Piscirickttesia salmonis-challenged Salmo salar specimens and from the corresponding non-challenged controls. Exosomes presented a spherical morphology and particle size distribution within 50–125 nm, showing similar parameters in both groups. The mass spectrometry analysis of exosomes isolated at 14 and 21 d post-challenge showed the presence of peptides corresponding to the three proteins of Hsp70/DnaK chaperone system (DnaK, DnaJ, and GrpE). BLAST search of these peptides showed the specificity to P. salmonis. Data are available via ProteomeXchange with identifier PXD023594. ConclusionsThe chaperones were found with >95% identity in the core genome when aligned to 73 genomes of P. salmonis. The proteins also showed a high degree of similarity with other microorganisms, where this system has proven to be vital for their survival under stress conditions.The presence of these three proteins in exosomes isolated from challenged fish sera calls for further study into their potential role in bacterium pathogenicity.How to cite: Muñoz C, Carmona M, Luna O, et al. Serum-isolated exosomes from Piscirickettsia salmonis-infected Salmo salar specimens enclose bacterial DnaK, DnaJ and GrpE chaperones. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.07.003.

Chicken Gut Microbiota Responses to Dietary Bacillus subtilis Probiotic in the Presence and Absence of Eimeria Infection.

Coccidiosis is a well-known poultry disease that causes the severe destruction of the intestinal tract, resulting in reduced growth performance and immunity, disrupted gut homeostasis and perturbed gut microbiota. Supplementation of probiotics were explored to play a key role in improving growth performance, enhancing innate and adaptive immunity, maintaining gut homeostasis and modulating gut microbiota during enteric infection. This study was therefore designed to investigate the chicken gut whole microbiota responses to Bacillus subtilis (B. subtilis) probiotic feeding in the presence as well as absence of Eimeria infection. For that purpose, 84 newly hatched chicks were assigned into four groups, including (1) non-treated non-challenged control group (CG − ET), (2) non-treated challenged control group (CG + ET), (3) B. subtilis-fed non-challenged group (BS − ET) and (4) B. subtilis-fed challenged group (BS + ET). CG + ET and BS + ET groups were challenged with Eimeria tenella (E. tenella) on 21 day of housing. Our results for Alpha diversity revealed that chickens in both infected groups (CG + ET and BS + ET) had lowest indexes of Ace, Chao 1 and Shannon, while highest indexes of Simpson were found in comparison to non-challenged groups (CG − ET and BS − ET). Firmicutes was the most affected phylum in all experimental groups following Proteobacteria and Bacteroidota, which showed increased abundance in both non-challenged groups, whereas Proteobacteria and Bacteroidota affected both challenged groups. The linear discriminant analysis effect size method (lEfSe) analysis revealed that compared to the CG + ET group, supplementation of probiotic in the presence of Eimeria infection increased the abundance of some commensal genera, included Clostridium sensu stricto 1, Corynebacterium, Enterococcus, Romboutsia, Subdoligranulum, Bacillus, Turicibacter and Weissella, with roles in butyrate production, anti-inflammation, metabolic reactions and the modulation of protective pathways against pathogens. Collectively, these findings evidenced that supplementation of B. subtilis probiotic was positively influenced with commensal genera, thereby alleviating the Eimeria-induced intestinal disruption.

Effects of mixed Eimeria challenge on performance, body composition, intestinal health, and expression of nutrient transporter genes of Hy-Line W-36 pullets (0-6 wks of age)

A study was aimed to investigate the effects of mixed Eimeria challenge on performance, gastrointestinal health, oxidative stress, inflammation, and expression of nutrient transporter genes of Hy-Line W-36 pullets. A total of 540, 16-d old pullets were randomly allocated into 5 treatment groups with 6 replicate cages, including a nonchallenged control group. A mixed Eimeria species solution containing 50,000 E. maxima, 50,000 E. tenella, and 250,000 E. acervulina oocysts per mL was prepared and challenged to one group as a high-dose treatment (High). The 2-fold serial dilution was done to prepare the medium-high (Med-High: 25,000 E. maxima; 25,000 E. tenella; and 125,000 E. acervulina), the medium-low (Med-Low: 12,500 E. maxima; 12,500 E. tenella; and 62,500 E. acervulina), and the low (Low: 6,250 E. maxima; 6,250 E. tenella; and 31,250 E. acervulina) dose treatments, and these dosages were challenged to 3 remaining groups, respectively. Growth performance, daily feed intake (FI), and mortality were calculated from 0-14 d postinfection (DPI). Gastrointestinal permeability (GP) was measured on 3, 5, 6, 7, and 9 DPI. The result indicated significant linear responses to the Eimeria challenge dosage in average body weight and body weight gain (P < 0.0001). An interaction between treatment and DPI was observed for FI (P < 0.0001). Feed intake significantly dropped from 4 DPI and did not recover until 12 DPI in the challenged groups. The lowest FI for each of the challenged groups was observed on 5 DPI. Gastrointestinal permeability increased linearly, peaking at 5 DPI, and was recovered back to normal by 9 DPI in the challenged groups. Furthermore, gene expression of tight junction proteins was linearly upregulated by increased Eimeria dosages. The oxidative status of the pullets was lowered in the challenged groups than the nonchallenged control group, whereas the expression of inflammatory and proinflammatory cytokines was upregulated by Eimeria challenge on 6 DPI (P < 0.05). The highest mortality was observed in pullets challenged with the High, followed by the Med-High (P < 0.0001) on 5 DPI. In summary, the mixed Eimeria challenge linearly reduced the growth performance of pullets with an increase in oxidative stress and inflammation. A severe effect of Eimeria on gastrointestinal health was observed on 5 or 6 DPI as suggested by GP, tight junction genes, and mortality results. This study indicates that Eimeria infection can be a threat to gastrointestinal health related issues in pullets.

Long Bone Mineral Loss, Bone Microstructural Changes and Oxidative Stress After Eimeria Challenge in Broilers.

The objective of this study was to evaluate the impact of coccidiosis on bone quality and antioxidant status in the liver and bone marrow of broiler chickens. A total of 360 13-day old male broilers (Cobb 500) were randomly assigned to different groups (negative control, low, medium-low, medium-high, and highest dose groups) and orally gavaged with different concentrations of Eimeria oocysts solution. Broiler tibia and tibia bone marrow were collected at 6 days post-infection (6 dpi) for bone 3-D structural analyses and the gene expression related to osteogenesis, oxidative stress, and adipogenesis using micro-computed tomography (micro-CT) and real-time qPCR analysis, respectively. Metaphyseal bone mineral density and content were reduced in response to the increase of Eimeria challenge dose, and poor trabecular bone traits were observed in the high inoculation group. However, there were no significant structural changes in metaphyseal cortical bone. Medium-high Eimeria challenge dose significantly increased level of peroxisome proliferator-activated receptor gamma (PPARG, p < 0.05) and decreased levels of bone gamma-carboxyglutamate protein coding gene (BGLAP, p < 0.05) and fatty acid synthase coding gene (FASN, p < 0.05) in bone marrow. An increased mRNA level of superoxide dismutase type 1 (SOD1, p < 0.05) and heme oxygenase 1 (HMOX1, p < 0.05), and increased enzyme activity of superoxide dismutase (SOD, p < 0.05) were found in bone marrow of Eimeria challenged groups compared with that of non-infected control. Similarly, enzyme activity of SOD and the mRNA level of SOD1, HMOX1 and aflatoxin aldehyde reductase (AKE7A2) were increased in the liver of infected broilers (p < 0.05), whereas glutathione (GSH) content was lower in the medium-high challenge group (p < 0.05) compared with non-challenged control. Moreover, the mRNA expression of catalase (CAT) and nuclear factor kappa B1 (NFKB1) showed dose-depend response in the liver, where expression of CAT and NFKB1 was upregulated in the low challenge group but decreased with the higher Eimeria challenge dosage (p < 0.05). In conclusion, high challenge dose of Eimeria infection negatively affected the long bone development. The structural changes of tibia and decreased mineral content were mainly located at the trabecular bone of metaphyseal area. The change of redox and impaired antioxidant status following the Eimeria infection were observed in the liver and bone marrow of broilers.

Tryptophan Supplementation Enhances Intestinal Health by Improving Gut Barrier Function, Alleviating Inflammation, and Modulating Intestinal Microbiome in Lipopolysaccharide-Challenged Piglets.

Tryptophan (Trp) can modify the gut microbiota. However, there is no information about the effect of Trp on intestinal microbiota after lipopolysaccharide (LPS) challenge. This study aimed to investigate the effect of Trp on intestinal barrier function, inflammation, antioxidant status, and microbiota in LPS-challenged piglets. A total of 18 weaned castrated piglets were randomly divided into three treatments with 6 replicate per treatment, namely, (i) non-challenged control (CON); (ii) LPS-challenged control (LPS-CON); and (iii) LPS + 0.2% Trp (LPS-Trp). After feeding with control or 0.2% tryptophan-supplemented diets for 35 days, pigs were intraperitoneally injected with LPS (100 μg/kg body weight) or saline. At 4 h post-challenge, all pigs were slaughtered, and colonic samples were collected. The samples were analyzed for gut microbiota, fatty acids, antioxidant parameters, and the expression of mRNA and protein. The community bar chart showed that Trp supplementation to LPS-challenged pigs increased the relative abundance of Anaerostipes (P < 0.05) and tended to increase the relative abundance of V9D2013_group (P = 0.09), while decreased the relative abundance of Corynebacterium (P < 0.05) and unclassified_c__Bacteroidia (P < 0.01). Gas chromatography showed that Trp increased the concentrations of acetate, propionate, butyrate, and isovalerate in the colonic digesta (P < 0.05). Trp reduced the mRNA level of pro-inflammatory cytokines (P < 0.01), and increased mRNA level of aryl hydrocarbon receptor, cytochrome P450 (CYP) 1A1 and CYP1B1 (P < 0.05). Correlation analysis results showed that acetate, propionate, and butyrate concentrations were positively correlated with mRNA level of occludin and CYP1B1 (P < 0.05), and were negatively correlated with pro-inflammatory cytokines gene expression (P < 0.05). Isovalerate concentration was positively correlated with catalase activity (P < 0.05), and was negatively correlated with pro-inflammatory cytokines gene expression (P < 0.05). Furthermore, Trp enhanced the antioxidant activities (P < 0.01), and increased mRNA and protein expressions of claudin-1, occludin, and zonula occludens-1 (P < 0.01) after LPS challenge. These results suggest that Trp enhanced intestinal health by a modulated intestinal microbiota composition, improved the short chain fatty acids synthesis, reduced inflammation, increased antioxidant capacity, and improved intestinal barrier function.

Effect of Dietary Organic and Inorganic Sulfur on the Performance of Coccidiosis Vaccine Challenged Broiler Chickens.

Simple SummaryCoccidiosis is a parasitic disease in poultry that causes significant economic losses. It is understood that natural or synthetic antioxidants including plant extracts, vitamin E, and selenium have been proved to lessen the gut severity of Eimeria infection in chickens. Sulfur is an essential element and exhibits beneficial activities including parasitic, antioxidant, and anti-inflammatory. These functional features of sulfur might play a role in inhibiting the negative effect of chicken coccidiosis and, if proved, sulfur could be used as an anticoccidial agent. We tested dietary sulfur of both organic and inorganic forms with beneficial antioxidant properties in a mild coccidiosis disease broiler chicken model.The objective of this study was to evaluate the effects of dietary sulfur from either organic (methyl sulfonyl methane, MSM) or inorganic (sodium sulfate, SS) sources on the growth performance of broiler chickens challenged against a high-dose coccidiosis vaccine. A total of 320 day-old Ross 308 broiler chicks were randomly placed into 32 pens of 10 birds each (keeping 16 pens/control group and 8 pens/treatment group until 21 days post-hatch) and reared for 28 days. The experimental diets were formulated by mixing a corn and soybean meal-based control diet with MSM or SS. At 21 days post-hatch, half (n = 8) of the control and all of the sulfur-added diet-fed (i.e., MSM and SS) groups were challenged with a 30-fold dose of a commercially available Eimeria vaccine (Livacox® T coccidiosis vaccine). Unchallenged control chicks (n = 8) were considered as the negative control group. At 21 days (before coccidiosis vaccine challenge), the production parameters and cecal short-chain fatty acids were not affected by dietary treatments. The concentrations of total antioxidant capacity in liver samples were elevated in both the MSM and SS groups compared with the control group (p = 0.001). During 21 to 28 days (i.e., one week post coccidiosis vaccine challenge), challenge tended to lower body weight and feed intake by an average of 5.3% (p = 0.262) and 2.8% (p = 0.504), respectively, but to increase the feed conversion ratio by an average of 2.7% (p = 0.087) compared with the non-challenged control groups. None of dietary sulfur groups affected the body weight gain, feed intake, or feed conversion ratio of vaccine-challenged chickens. Mild Eimeria-specific lesions were noted in duodenum (p = 0.006), jejunum (p = 0.017), and ceca (p = 0.047), but dietary sulfur treatments did not affect the Eimeria-induced gut lesion scores. At 28 days, Eimeria challenge significantly impaired (p = 0.001) the apparent ileal digestibility of crude protein and crude ash compared with the naïve control group. Dietary MSM increased the apparent ileal digestibility of crude ash by 15.5% on average compared with the coccidiosis vaccine control group. We conclude that dietary antioxidant sulfur of organic or inorganic origins at the inclusion level (i.e., 0.7 g sulfur/kg of diet) has a limited effect on the growth performance of chickens challenged with coccidiosis vaccine.

Dietary Tryptophan Supplementation Improves Antioxidant Status and Alleviates Inflammation, Endoplasmic Reticulum Stress, Apoptosis, and Pyroptosis in the Intestine of Piglets after Lipopolysaccharide Challenge.

Tryptophan can alleviate stress and improve intestinal health, but the precise mechanism has not been fully elucidated. This study aimed to examine the effects of tryptophan supplementation on antioxidant status, inflammation, endoplasmic reticulum (ER) stress, apoptosis, and pyroptosis signaling pathway in the intestine of piglets after Escherichia coli lipopolysaccharide (LPS) challenge. Thirty-two weaning piglets were allotted to four treatments including: non-challenged control, LPS-challenged control, LPS + 0.2% tryptophan and LPS + 0.4% tryptophan. On day 35 of feeding, piglets were injected intraperitoneally with 100 μg/kg of body weight LPS or saline. Among the LPS-challenged pigs, tryptophan supplementation improved intestinal morphology as indicated by greater villus height, villus area and smaller crypt depth, and antioxidant status, and decreased the mRNA expression and concentration of proinflammatory cytokines. Moreover, tryptophan downregulated the expression of ER stress (ER oxidoreductase-1α, ER oxidoreductase-1β, glucose-regulated protein-78, activating transcription factor 6, C/EBP homologous protein), apoptosis (B-cell lymphoma-2, BCL2-associated X protein, caspase 3), and pyroptosis signaling pathway (nucleotide-binding oligomerization domain-like receptor protein 3, caspase 1, gasdermin-D, apoptosis-associated speck-like protein containing a CARD). Collectively, tryptophan supplementation can contribute to gut health by improving antioxidant status and alleviating inflammation, ER stress, apoptosis, and pyroptosis in the intestine of piglets after lipopolysaccharide challenge.

Glutamate attenuates lipopolysaccharide induced intestinal barrier injury by regulating corticotropin-releasing factor pathway in weaned pigs.

ObjectiveThe purpose of this study was to evaluate the protection of glutamate (GLU) against the impairment in intestinal barrier function induced by lipopolysaccharide (LPS) stress in weaned pigs.MethodsTwenty-four weaned pigs were divided into four treatments containing: i) non-challenged control, ii) LPS-challenged control, iii) LPS+1.0% GLU, and iv) LPS+2.0% GLU. On day 28, pigs were treated with LPS or saline. Blood samples were collected at 0, 2, and 4 h post-injection. After blood samples collection at 4 h, all pigs were slaughtered, and spleen, mesenteric lymph nodes, liver and intestinal samples were obtained.ResultsDietary GLU supplementation inhibited the LPS-induced oxidative stress in pigs, as demonstrated by reduced malondialdehyde level and increased glutathione level in jejunum. Diets supplemented with GLU enhanced villus height, villus height/crypt depth and claudin-1 expression, attenuated intestinal histology and ultrastructure impairment induced by LPS. Moreover, GLU supplementation reversed intestinal intraepithelial lymphocyte number decrease and mast cell number increase induced by LPS stress. GLU reduced serum cortisol concentration at 4 h after LPS stress and downregulated the mRNA expression of intestinal corticotropin-releasing factor signal (corticotrophin-releasing factor [CRF], CRF receptor 1 [CRFR1], glucocorticoid receptor, tryptase, nerve growth factor, tyrosine kinase receptor A), and prevented mast cell activation. GLU upregulated the mRNA expression of intestinal transforming growth factor β.ConclusionThese findings indicate that GLU attenuates LPS-induced intestinal mucosal barrier injury, which is associated with modulating CRF signaling pathway.

Bacterin Vaccination Provides Insufficient Protection Against Streptococcus equi Subspecies zooepidemicus Infection in Pigs.

Streptococcus equi subspecies zooepidemicus (SEZ) is a zoonotic pathogen capable of causing severe disease in many mammalian species. Historically, SEZ has not been a common cause of disease in pigs in North America; however, in 2019, SEZ caused mortality events leading to severe illness and 30–50% mortality in exposed animal groups. Because of the rapid progression of disease, it is important to investigate intervention strategies to prevent disease development. In this study, pigs were divided into four groups: (1) vaccinated with an inactivated SEZ vaccine generated from a highly mucoid 2019 mortality event isolate; (2) vaccinated with an inactivated SEZ vaccine generated from a genetically similar, non-mucoid isolate from a guinea pig; (3) and (4) sham vaccinated. Following boost vaccination, groups 1–3 were challenged with a 2019 mortality event isolate and group 4 were non-challenged controls. Antibody titers were higher for SEZ vaccinated animals than sham vaccinated animals; however, no anamnestic response was observed, and titers were lower than typically seen following the use of inactivated vaccines. Vaccination did not provide protection from disease development or mortality following challenge, which could be associated with the comparatively low antibody titers generated by vaccination. Surviving pigs also remained colonized and transmitted SEZ to naïve contact pigs 3 weeks following challenge, indicating that healthy animals can act as a source of SEZ exposure. Future investigation should evaluate different vaccine formulations, such as increased antigen load or an alternative adjuvant, that could induce a more robust adaptive immune response.

Influence of Brassica spp. rapeseed and canola meal, and supplementation of bioactive compound (AITC) on growth performance, intestinal-permeability, oocyst shedding, lesion score, histomorphology, and gene expression of broilers challenged with E. maxima

This study was performed to investigate the effect of feeding Brassica spp. including full-fat rapeseed, canola meal, and allyl isothiocyanate (AITC) to broiler chicken challenged with E. maxima. A total of 576 one-day old male broiler chicks were completely randomized to 8 treatments with 6 replicated cages and 12 birds per cage. The treatment diets consisted of nonchallenge control (NC, corn-SBM based diet), challenge control (CC), 10% rapeseed (10RS), 30% rapeseed (30RS), 20% canola (20CLM), 40% canola (40CLM), 500 ppm AITC (500AITC), and 1,000 ppm AITC (1000AITC). At d 14, all birds were challenged, except NC group, with a subclinical dose of E. maxima. Intestinal permeability was conducted on 5 d post-infection (dpi) and for oocyst shedding 5 to 6 dpi feces were pooled and collected. On 6 dpi, growth performance, lesion score, histomorphology, and gene expression were measured. The growth performance result showed that 10RS and 30RS groups had lower BW, BWG, FI, and higher FCR (P < 0.0001). During the challenge and overall periods, NC group had highest BW, BWG, and FI, and lowest FCR. The inclusion of canola meal showed lower performance during prechallenge period but was able to catch up BWG during challenge period. The AITC levels showed similar growth performance to CC group. Intestinal permeability for 20CLM, 40CLM, 500AITC and 1000AITC was similar to NC group, whereas CC, 10RS, and 30RS had higher permeability compared to NC (P < 0.0001). Oocyst shedding was significantly lower for 40CLM and NC, whereas all other treatments had higher oocyst shedding (P < 0.0001). All the challenged treatment groups had higher lesion score and microscore than NC (P < 0.0001). Histomorphology data showed that jejunum villus height (VH) for 1000AITC was similar to NC group, whereas CC group had the lowest VH (P = 0.01). The 30RS group had lower VH: crypt depth (CD) ratio in the jejunum and ileum. The gene expression at 6 dpi for claudin1, occludin, IL2, IL6, GLUT5, EAAT, BoAT, and LAT1 was significantly changed among the treatments. The results suggest that 30RS retards growth performance and deteriorate gut health during coccidiosis and should not be fed to chicken during the starter phase. Canola meal showed decline in growth prechallenge but maintained growth and intestinal health during the challenge period at 40% inclusion. AITC at 1,000 ppm showed similar growth as control group, but with improved gut health during the challenge period. Canola meal could be a good alternative to SBM especially during coccidiosis, whereas AITC needs to be tested vigorously in animal feeding regime.

Influence of rapeseed, canola meal and glucosinolate metabolite (AITC) as potential antimicrobials: effects on growth performance, and gut health in Salmonella Typhimurium challenged broiler chickens

Poultry is the major sources of foodborne salmonellosis. Antibiotic resistance and a surge in zoonotic diseases warrant the use of natural alternatives. Glucosinolates (GLs) are naturally occurring antimicrobial compounds in rapeseed and canola. This study investigated the effect of feeding rapeseed, canola meal, and allyl isothiocyanate (AITC; Brassica secondary metabolites) on growth performance (GP), gut health, and the potential antimicrobial activity against nalidixic acid-resistant Salmonella Typhimurium (STNR) in chickens. A total of 640 one-day-old male Cobb 500 broilers were randomly allocated to 8 treatments with 8 replicated cages and 10 birds per cage. Dietary treatments were nonchallenge control (NC, corn-SBM based), challenge (Salmonella) control (CC), 10% rapeseed (10RS), 30% rapeseed (30RS), 20% canola meal (20CLM), 40% canola meal (40CLM), 500 ppm AITC (500AITC), and 1,500 ppm AITC (1500AITC). On d 1, all the birds except NC were orally challenged with STNR (7 log CFU/bird). The chickens were reared for 21 d, and their FI and BW were recorded weekly. Salmonella cecal colonization and fecal shedding were quantified, whereas organ translocation (OT) of STNR to the spleen, liver, and kidney was tested on 0, 3, 6, 13, and 20-d postchallenge (dpc). Data were subjected to one-way ANOVA, and the means were separated by Duncan's test, except mortality and OT data analyzed after transformation by square root of (n +1) (P < 0.05). Overall, feeding 30RS resulted in reduced BW (P = 0.003), BWG (P = 0.003), and FI (P = 0.001) compared to CC, 500AITC, and 1500AITC. Similarly, feeding 20CLM resulted in lower BW and BWG compared to CC (P < 0.05) and increased FCR compared to 1500AITC (P = 0.03). Feeding CC resulted in higher mortality compared to NC and 30RS (P = 0.03). Cecal colonization of STNR was reduced (P < 0.0001) for 30RS on 6 dpc and 500AITC on 6 and 13 dpc (P < 0.0001). Although no difference in gut permeability was observed 6 dpc (P > 0.05), OT of STNR population was the highest for CC in the spleen (P = 0.05). In the liver, 10RS showed reduced OT compared to 20CLM on 13 dpc (P = 0.03), whereas 30RS showed the lowest OT on 6 dpc in the kidney. Fecal shedding was lowest for 30RS on 6 dpc (P = 0.004). Histomorphology showed 30RS had the highest duodenum (P = 0.01) and jejunum (P = 0.02) villus height (VH) and VH to crypt depth (CD) ratio compared to the other treatments, whereas 1500AITC showed similar results to 30RS. Both 30RS and 1500AITC contained comparatively higher functional GL metabolites and were able to maintain gut health. Including higher levels of rapeseed or AITC in poultry feed can reduce Salmonella colonization in the feces and their translocation to other organs.

Effect of organic acids on growth performance, intestinal morphology, and immunity of broiler chickens with and without coccidial challenge

A total of 360-day-old broiler chicks were allocated into six groups in 2 (Coccidial challenge or not) × 3 (dietary treatments) factorial design. Three dietary treatments including: basic diet, basic diet plus organic acids (OAs) in drinking water, and basic diet plus OAs in the feed with and without coccidial challenge. The OAs in water or feed improved (P < 0.01) average body weight (ABW), average body weight gain (ABWG), and feed conversion ratio (FCR) as compared with the control diet during starter, grower, and whole experimental period. Coccidial challenge decreased BW, ABWG, and average feed intake (AFI), as well as resulted in poor FCR during the starter and whole experimental period (P < 0.05). Though there was no interaction between OAs supplementation and coccidial challenge, the OAs supplementation improved the overall performance with and without coccidial challenge birds on 21 d and 35 d. IgG was found higher (P = 0.03) in broilers fed OAs in feed without the coccidial challenge group. On 18 d, OAs supplementation in feed increased TNF-γ (P = 0.006), whereas the coccidial challenge decreases TNF-γ (P = 0.01) and IL-10 (P = < .0001), and increases IgM (P = 0.03), IgG (P = 0.04) and IgA (P = 0.02). On 29 d, the coccidial challenge increases IgM and IgA. On 18 d, jejunal lesion score was found significantly higher in the coccidial challenged group as compared to OAs supplementation with coccidial challenged groups on 18 d (P < 0.0001) and 29 d (P = 0.03). Crypt depth was higher, and Villus-height to Crypt depth ratio was lower in the coccidial challenge group on 18 and 29 d. The Goblet cells were found higher in the non-coccidial challenge on 18 d. After 18 d, 16S rDNA gene sequence analysis of ileal chyme has shown that coccidial challenge decreases Lactobacillus_reuteri species as compared to the non-challenged group (P = 0.02). After 29, Cyanobacteria abundance reduced (P = 0.014) in the challenged group than the non-challenged group at the phylum level. At the genus level, Lactobacillus (P = 0.036) and unidentified Cyanobacteria (P = 0.01) were found higher in the non-challenged group than the coccidial challenge group. The results indicate that the OAs supplementation showed improved responses in a pattern similar to the non-challenged control group by neutralizing the negative effects of the coccidial challenge.

Research Note: Evaluation of quinine as a chemoprophylactic candidate against histomoniasis in turkeys

Histomoniasis, also commonly referred to as blackhead disease, is caused by the protozoan parasite Histomonas meleagridis. Since the removal of nitarsone in 2015, no approved prophylactics are available for mitigating histomoniasis. Disease incidence and high mortalities are frequently associated with turkey flocks, although infection of broiler breeders also occurs. Quinine is a naturally occurring alkaloid with antimalarial properties. In vitro assays have shown strong antihistomonal properties of quinine, leading to our hypothesis that quinine inclusion within the feed could prevent histomoniasis in turkeys. Selected concentrations of quinine were included within a turkey starter diet to evaluate effects on body weight gain (BWG), liver lesions, cecal lesions, and mortality of H. meleagridis-challenged turkeys. On day-of-hatch, poults were randomly assigned to either the basal diet or a quinine diet. Groups consisted of a non-challenged control (NC; basal diet), 0.022% quinine + challenge, 0.067% quinine + challenge, 0.2% quinine + challenge, or a positive-challenged control (PC; basal diet). On d 10, challenged groups were intracloacally inoculated with 105H. meleagridis cells/turkey, and lesions were evaluated on d 21 post-infection. Individual body weights were recorded on d 0, d 10, and d 31 to calculate the pre-challenge and post-challenge BWG. No significant differences (P > 0.05) were observed between the d 0 to 10 pre-challenged BWG between quinine treatment diets and the basal diet. Similarly, no differences (P > 0.05) were observed in post-challenge d10-31 BWG of the quinine dietary treatments as compared to the PC. Cumulative mortalities, liver lesions, and cecal lesions related to histomoniasis were not reduced (P > 0.05) in any of the quinine treatment groups as compared to the PC. Although quinine successfully reduced H. meleagridis cells in vitro, results from the in vivo experiment indicated no reduction in histomoniasis severity as evidenced by similar lesions and mortality as the PC. Taken together, these data indicate that quinine inclusion within the feed at these concentrations and under these experimental conditions was not efficacious in the prevention or treatment of histomoniasis.