Protected biofactors and antioxidants reduce the negative consequences of virus and cold challenge by modulating immunometabolism via changes in the interleukin-6 receptor signaling cascade in the liver

Protected biofactors and antioxidants (PBA), and protected biofactors and antioxidants with protected organic acids and essential oils (PBA+POAEO) have been shown to have benefits in stressed or challenged birds. Here, we describe the immunometabolic changes observed in the liver of Ross 308 broilers during feed supplementation and brief physiological stress. These studied additives contain protected essential oils, organic acids, and vitamins which may have protective effects on the liver. Thus, we aimed to determine the signaling changes induced by these supplements and the resultant immunometabolic effects in the liver. All birds received a 2X dose of live bronchitis vaccine at d 0 and a 48-h cold challenge by reducing the temperature from 30 to 32°C, to 20 to 23°C on d 3 to 5. Control birds were fed a standard diet without supplementation. Liver samples were collected to evaluate the effects of these treatments on cytokine gene expression and protein phosphorylation via kinome peptide array. ANOVA was used for statistical analysis of the gene expression data (significance at a p-value of 0.05), and PIIKA2 was used for statistical evaluation and comparative analysis of the kinome peptide array data. At d 15, the kinome peptide array analysis and gene expression data showed stimulation of the interleukin 6 receptor (IL-6R) signal transduction for host protection via heightened immune response while inducing immune modulation and reducing inflammation in both supplement treated groups. Significant changes were observed via IL-6R signaling in the metabolic profiles of both groups compared to control and no significant differences when compared to each other. In the liver, these 2 feed additives induced immunometabolic changes predominantly via the IL-6 receptor family signaling cascade. Differences between the 2 treated groups were predominantly in the metabolic pathways, centered around the mTOR pathway and the proteins AMPK, mTOR and S6K, with a more anabolic phenotype following the addition of essential oils.

Graded levels of Eimeria infection linearly reduced the growth performance, altered the intestinal health, and delayed the onset of egg production of Hy-Line W-36 laying hens when infected at the prelay stage

The aim of this experiment was to investigate how different levels of Eimeria infection affect the performance, intestinal health, oxidative status, and egg production of Hy-Line W-36 pullets and laying hens. Three hundred and sixty Hy-Line W-36 pullets, aged 15 wk, were randomly distributed into 5 treatment groups, each comprising 6 replicates and a nonchallenged control. At 15 wk, pullets were inoculated with different levels of mixed Eimeria species as high-dose, medium-high, medium-low, and low-dose treatments. The growth performance and average daily feed intake (ADFI) were measured from 0- to 18-days postinoculation (DPI), whereas hen day egg production (HDEP) was recorded from wk 19. The markers of gastrointestinal health and oxidative status were measured at 6 DPI, 14 DPI, and 23 wk of age. The findings revealed a significant linear reduction in growth performance in response to increased Eimeria challenge dosage on 6 and 14 DPI (P < 0.0001, P-L < 0.0001). An interaction between the graded level of Eimeria infection and DPI was observed for ADFI. The challenged pullets showed a reduction in ADFI starting at 4 DPI, which persisted until 14 DPI, when ADFI recovered back to normal. The most significant drop in feed intake was observed in 6 DPI in all the Eimeria-infected groups. The markers of gastrointestinal health (gastrointestinal permeability and tight junction proteins) were upregulated in challenged pullets because of infection, whereas the relative mRNA expression of key nutrient transporters was downregulated following infection on 6 and 14 DPI (P < 0.05). As a result of an infection on 6 DPI, the oxidative equilibrium was shifted toward the oxidative stress, and at the same time, upregulation of proinflammatory and inflammatory cytokines was observed (P < 0.05). An interaction between the Eimeria challenge dosage and bird age was observed for HDEP (P = 0.0427). The pullets infected with Eimeria started to lay eggs later than the Control birds. However, the HDEP of the challenged groups became similar to Control only at wk 22, 3 wk after laying eggs. In conclusion, coccidiosis reduced growth performance, altered gastrointestinal health, induced oxidative stress, and delayed egg production when infected at the prelay stage of pullets and negatively impacted the laying hens' overall performance.

Graded levels of Eimeria infection modulated gut physiology and temporarily ceased the egg production of laying hens at peak production

An experiment was conducted to investigate the changes in gastrointestinal physiology, including intestinal leakage, immune response, oxidative stress, along with performance traits, of Hy-Line W-36 laying hens following Eimeria infection at peak egg production. A total of 360 laying hens, at 25 wk of age, were assigned randomly to 5 treatment groups, each consisting of 6 replicate cages, including a nonchallenged control group. The other 4 groups were inoculated with graded levels of mixed Eimeria species as high, medium-high, medium-low, and low doses, respectively. The body weight (BW) and body weight gain (BWG) of laying hens were measured from 0 to 14 days postinoculation (DPI). Average daily feed intake (ADFI) and hen-day egg production (HDEP) were measured from 0 to 15 and 0 to 28 DPI, respectively. Gut permeability was measured on 5 DPI, whereas oxidative stress, immune response, and expression of nutrient transporter genes were measured on 6 and 14 DPI. A significant linear reduction in BW and BWG was observed with increased Eimeria inoculation dosage on both 6 and 14 DPI (P < 0.001, P-Lin < 0.0001). An interaction between the Eimeria dosages and DPI was observed for ADFI (P < 0.0001). Feed intake in the challenged groups decreased starting at 4 DPI, with the most significant drop occurring at 7 DPI, which did not recover until 15 DPI. Following the challenge, gastrointestinal physiology shifted toward the host defense against the Eimeria infection by upregulating mRNA expression of tight junction proteins and immune responses while downregulating the expression of key nutrient transporters on 6 and 14 DPI (P < 0.05). An interaction between the Eimeria inoculation dosage and DPI was also observed for daily HDEP (P < 0.0001). Overall, HDEP was lower in the challenged groups compared to the control. Daily HDEP in the challenged groups dropped from 8 DPI and became similar to the control birds only after 24 DPI. Egg production temporarily ceased in most of the laying hens infected with the high and medium-high dosages of Eimeria. In conclusion, Eimeria infection activated the host immune response, negatively affecting the gastrointestinal health, growth performance, and temporarily ceased the egg production of Hy-Line W-36 laying hens when infected at peak production.

Applying different morphometric intestinal mucosa methods and the correlation with broilers performance under Eimeria challenge

The intestinal wall has on its surface, protrusions called villi that are responsible for the absorption of nutrients. Commonly, these structures have their dimensions measured to related more area surface with better absorption. However, the measurement of these villi neglects the inflammation and the presence of immature cells that increase the surface area but affect negatively the absorption and compromise the animal performance. The measurements of villi/crypt are traditional tools in animal research; however, they may overlook alterations that impact the mucosal functionality. This study aimed to compare the morphometry of the intestinal villi/crypt with the I See Inside (ISI) scoring methodology, exploring their correlation with zootechnical performance. Therefore, broilers were grouped as nonchallenged (NC) and challenged with Eimeria (CH) and jejunum samples were collected at 22 d for histological analysis. The same villi were submitted to the ISI methodology, which is based on the scoring of 8 parameters related to the inflammatory process, and the measurements of villus height (VH), villus width (VW), crypt depth (CD), crypt width (CW), VH:CD ratio and villi absorptive surface (VAS). The CH group presented higher ISI total score, VW, CD, CW and lower VH, VH:CD, and VAS in comparison to the NC group. While the villi/crypt morphometry did not exhibit correlations with performance, the presence of Eimeria oocysts and the ISI total score was positively correlated (P < 0.05) with the feed conversion ratio (FCR), demonstrating a statistical interaction between high ISI scores and worse performance. In conclusion, a larger villus is not related to better intestinal functionality when this enlargement is unleashed by the immune processes occurring inside. The scoring system that evaluates the type of alteration observed has a direct impact on the animal's zootechnical performance which is not observed with the single metric surface evaluation.

Osteoimmunology: A Link between Gastrointestinal Diseases and Skeletal Health in Chickens

Bone serves as a multifunctional organ in avian species, giving structural integrity to the body, aiding locomotion and flight, regulating mineral homeostasis, and supplementing calcium for eggshell formation. Furthermore, immune cells originate and reside in the bone marrow, sharing a milieu with bone cells, indicating a potential interaction in functions. In avian species, the prevalence of gastrointestinal diseases can alter the growth and the immune response, which costs a great fortune to the poultry industry. Previous studies have shown that coccidiosis and necrotic enteritis can dramatically reduce bone quality as well. However, possible mechanisms on how bone quality is influenced by these disease conditions have not yet been completely understood, other than the reduced feed intake. On the other hand, several mediators of the immune response, such as chemokines and cytokines, play a vital role in the differentiation and activation of osteoclasts responsible for bone resorption and osteoblasts for bone formation. In the case of Eimeria spp./Clostridium perfringens coinfection, these mediators are upregulated. One possible mechanism for accelerated bone loss after gastrointestinal illnesses might be immune-mediated osteoclastogenesis via cytokines-RANKL-mediated pathways. This review article thus focuses on osteoimmunological pathways and the interaction between host immune responses and bone biology in gastrointestinal diseases like coccidiosis and necrotic enteritis affecting skeletal health.

Enhancing egg production and quality by the supplementation of probiotic strains (Clostridium and Brevibacillus) via improved amino acid digestibility, intestinal health, immune response, and antioxidant activity

This study focused on evaluating the influence of Clostridium butyricum and Brevibacillus strains on egg production, egg quality, immune response and antioxidant function, apparent fecal amino acid digestibility, and jejunal morphology when supplemented as probiotics in the diets of laying hens in the peak phase. A total of 288 healthy 30-week-old Hy-Line Brown laying hens were arbitrarily assigned to four dietary groups, which included control diet and control diet supplemented with 0.02% C. butyricum zlc-17, C. butyricum lwc-13, or Brevibacillus zlb-z1, for 84 days. The results showed that dietary C. butyricum and Brevibacillus sp. exerted a positively significant influence (P ≤ 0.05) compared to the control group on the performance, egg quality, and physiological response of the birds. The diets could reduce mortality rate and enhance (P ≤ 0.05) egg weight and egg mass, egg production rate, and feed efficiency. Further analysis suggested that the probiotic strains can enhance (P ≤ 0.05) eggshell quality, Haugh unit, thick albumen content, and albumen height. Also, probiotics enhanced (P ≤ 0.05) the antioxidant status via increased antioxidant enzymes and jejunal morphology as evidenced by increased villi surface area (VSA), the ratio of villi height to crypt depth, villi width, and villi height, and a significant reduction in crypt depth. Besides, nutrient absorption and retention were enhanced, as apparent fecal amino acid digestibility of key essential amino acids was substantially improved in the diet-based group. The concentrations of immunoglobulin M and A (IgM and IgA) increased significantly (P ≤ 0.05) in the probiotics group and the same effect was notable for complement proteins (C3) and immune organ (Spleen). Conclusively, the supplementation of Clostridium butyricum zlc-17 in comparison to Clostridium butyricum lwc-13 and Brevibacillus zlb-z1 strains significantly (P ≤ 0.05) promoted the antioxidant status, modulated the intestinal structure, enhanced amino acid digestibility, and regulated the immunity index of the laying hens, which finally improves the laying performance and egg quality of the laying hens.

Dietary supplementation of sulfur amino acids improves intestinal immunity to Eimeria in broilers treated with anti-interleukin-10 antibody

Oral antibody to interleukin-10 (anti-IL-10) enhances the intestinal immune defense against Eimeria. The sulfur amino acids methionine and cysteine (M+C) play essential roles in inducing and maintaining protective immune responses during intestinal infections. Hence, increased dietary M+C may support the anti-IL-10-induced intestinal immunity to Eimeria. Broilers (n = 640) were arranged in a 2 × 2 × 2 factorial design with 2 levels of each of the 3 main factors: dietary standardized ileal digestible (SID) M+C levels (0.6% or 0.8%), dietary anti-IL-10 supplementation (with or without), and coccidiosis challenge (control or challenge). Briefly, the broilers were supplied with either 0.6% or 0.8% SID M+C, each with or without anti-IL-10 (300 μg/kg), from d 10 to 21. On d 14, broilers from each diet were gavaged with either PBS or Eimeria. The resulting Eimeria infection induced fecal oocyst shedding and intestinal lesions. Broilers fed 0.8% SID M+C (main effects, P ≤ 0.05) had decreased feed-to-gain ratio, increased duodenum and cecum luminal anti-Eimeria IgA titers, and decreased fecal oocyst counts, when compared to 0.6% SID M+C. The supplementation of anti-IL-10 (main effects, P ≤ 0.05) increased cecum luminal total IgA concentration and decreased cecum lesions. Interactions (P ≤ 0.05) were detected for growth performance and cecum luminal IFN-γ. Briefly, the highest body weight gain and feed intake were reached in PBS-gavaged broilers fed 0.8% SID M+C with no anti-IL-10 and in Eimeria-challenged broilers fed 0.8% SID M+C with anti-IL-10. In Eimeria-infected broilers, anti-IL-10 increased intestinal luminal IFN-γ and body weight gain only at 0.8% SID M+C. Collectively, anti-IL-10 increased intestinal luminal IFN-γ levels, decreased cecum lesions and restored growth only when fed with adequate amounts of sulfur amino acids. Our findings underscore the importance of providing sufficient essential nutrients to support the anti-IL-10 induced immunity against coccidiosis.

In ovo Feeding as a Tool for Improving Performance and Gut Health of Poultry: A Review

Early growth and development of the gastrointestinal tract are of critical importance to enhance nutrients' utilization and optimize the growth of poultry. In the current production system, chicks do not have access to feed for about 48-72 h during transportation between hatchery and production farms. This lag time affects early nutrient intake, natural exposure to the microbiome, and the initiation of beneficial stimulation of the immune system of chicks. In ovo feeding can provide early nutrients and additives to embryos, stimulate gut microflora, and mitigate the adverse effects of starvation during pre-and post-hatch periods. Depending on the interests, the compounds are delivered to the embryo either around day 12 or 17 to 18 of incubation and via air sac or amnion. In ovo applications of bioactive compounds like vaccines, nutrients, antibiotics, prebiotics, probiotics, synbiotics, creatine, follistatin, L-carnitine, CpG oligodeoxynucleotide, growth hormone, polyclonal antimyostatin antibody, peptide YY, and insulin-like growth factor-1 have been studied. These compounds affect hatchability, body weight at hatch, physiological functions, immune responses, gut morphology, gut microbiome, production performance, and overall health of birds. However, the route, dose, method, and time of in ovo injection and host factors can cause variation, and thereby inconsistencies in results. Studies using this method have manifested the benefits of injection of different single bioactive compounds. But for excelling in poultry production, researchers should precisely know the proper route and time of injection, optimum dose, and effective combination of different compounds. This review paper will provide an insight into current practices and available findings related to in ovo feeding on performance and health parameters of poultry, along with challenges and future perspectives of this technique.

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.

Supplemental feeding of northern bobwhite (

Northern bobwhites (Colinus virginianus) are a well known game bird that has been extensively studied and managed throughout its range for many decades. Despite this, bobwhites have continued a steady annual decline across the United States, irrespective of many well established conservation practices in place to mitigate this. Supplemental feeding is one such technique that is a widely used tool in bobwhite management, but the methods and results of the studies to investigate the effectiveness of this method are highly variable. The effectiveness of supplemental feeding practices is further hindered by the limited knowledge regarding the nutritional requirements of wild bobwhite because many of the guidelines that researchers follow are based on species of Galliformes that are primarily used for production. Here, we review supplemental feeding studies, nutritional requirements of bobwhite, and discuss future directions.

Health Surveillance of Penguins in the Barton Peninsula on King George Island, Antarctica

Samples from 29 adult Gentoo (Pygoscelis papua), Chinstrap (Pygoscelis antarcticus), and Adélie Penguins (Pygoscelis adeliae) at the King Sejong Station on Nar̢ ebski Point, King George Island, Antarctica, were investigated to detect antibodies to avian influenza, Newcastle disease virus, infectious bursal disease virus, infectious bronchitis virus, Mycoplasma, and Salmonella. Antibodies were identified from one Gentoo Penguin and one Chinstrap Penguin against infectious bronchitis virus; from one Gentoo Penguin against Newcastle disease virus; from one Gentoo Penguin against Mycoplasma synoviae; and from two Chinstrap Penguins against Salmonella pullorum. Thirty-three dead penguin chicks were collected from the breeding colony for necropsy, histopathological examination, and polymerase chain reaction. Pulmonary hemorrhage and congestion were the main necropsy findings.

Monoglyceride Blend Reduces Mortality, Improves Nutrient Digestibility, and Intestinal Health in Broilers Subjected to Clinical Necrotic Enteritis Challenge

This study evaluated the potential of monoglyceride blend (MG) and buffered formic acid (FA) as alternatives to antibiotics in the performance and intestinal health of broilers under clinical necrotic enteritis (NE) challenge. A total of 544 as-hatched Ross 308 broiler chicks were randomly distributed to 32-floor pens housing 17 birds per pen. The four treatments were: NC-non-additive control; ZBS-antibiotic group supplemented with zinc bacitracin and salinomycin; MG-additive MG supplementation in the starter phase only; and MGFA-additive MG in starter phase and FA in grower and finisher phases. All birds were challenged with Eimeria spp. and Clostridium perfringens. Results showed that the NC group had lower BWG and higher FCR than the ZBS group in the grower and overall period (p < 0.05). The NC group had higher NE-caused mortality (days 14 to 17) than the ZBS group (p < 0.05). Birds fed MG had lower NE-caused mortality than the NC group (p < 0.05). Birds fed MG had upregulated jejunal tight junction protein1 (TJP1) and immunoglobulin (IgG) on day 16 and improved gross energy digestibility on day 24 than the NC group (p < 0.05). These findings suggest that supplementation of MG may improve intestinal health and protect birds from clinical NE occurrence.

Alternatives to Antibiotics: A Symposium on the Challenges and Solutions for Animal Health and Production

Antibiotics have improved the length and quality of life of people worldwide and have had an immeasurable influence on agricultural animal health and the efficiency of animal production over the last 60 years. The increased affordability of animal protein for a greater proportion of the global population, in which antibiotic use has played a crucial part, has resulted in a substantial improvement in human quality of life. However, these benefits have come with major unintended consequences, including antibiotic resistance. Despite the inherent benefits of restricting antibiotic use in animal production, antibiotics remain essential to ensuring animal health, necessitating the development of novel approaches to replace the prophylactic and growth-promoting benefits of antibiotics. The third International Symposium on “Alternatives to Antibiotics: Challenges and Solutions in Animal Health and Production” in Bangkok, Thailand was organized by the USDA Agricultural Research Service, Faculty of Veterinary Science, Chulalongkorn University and Department of Livestock Development-Thailand Ministry of Agriculture and Cooperative; supported by OIE World Organization for Animal Health; and attended by more than 500 scientists from academia, industry, and government from 32 nations across 6 continents. The focus of the symposium was on ensuring human and animal health, food safety, and improving food animal production efficiency as well as quality. Attendees explored six subject areas in detail through scientific presentations and panel discussions with experts, and the major conclusions were as follows: (1) defining the mechanisms of action of antibiotic alternatives is paramount to enable their effective use, whether they are used for prevention, treatment, or to enhance health and production; (2) there is a need to integrate nutrition, health, and disease research, and host genetics needs to be considered in this regard; (3) a combination of alternatives to antibiotics may need to be considered to achieve optimum health and disease management in different animal production systems; (4) hypothesis-driven field trials with proper controls are needed to validate the safety, efficacy, and return of investment (ROI) of antibiotic alternatives.

Probiotics and potential applications for alternative poultry production systems

Concerns over animal welfare continue to be a critical component of law and policies associated with commercial food animal production. Social and market pressures are the driving forces behind the legislation and result in the change of poultry production management systems. As a result, the movement toward cage-free and aviary-based egg production systems has become standard practices. Cage-based systems being replaced by alternative methods that offer a suitable housing environment to meet or exceed poultry welfare needs and require different management, including the ban of antibiotics in poultry diets. For broiler production, pasture- raised and free-range management systems have become more popular. However, challenges remain from exposure to disease-causing organisms and foodborne pathogens in these environments. Consequently, probiotics can be supplemented in poultry diets as commercial feed additives. The present review discusses the impacts of these probiotics on the performance of alternative poultry production systems for improving food safety and poultry health by mitigating pathogenic organisms and improving egg and meat quality and production.

The effects of feeding yeast bioactives to broiler breeders and/or their offspring on growth performance, gut development, and immune function in broiler chickens challenged with Eimeria

Yeast bioactives (YB) may stimulate broiler breeders (BB) to increase deposition of immunoglobulins (Ig) in eggs. We investigated the effects of feeding YB (mixture of derivatives from whole yeast subjected to enzymatic hydrolysis) to BB and/or their offspring on growth performance, gut development, and immune function in broiler chickens challenged with Eimeria. The BB (Ross 708 ♀ and Ross ♂) were assigned to 2 groups (60 ♀ and 10 ♂) and fed basal or basal diet supplemented with 500 g of YB/Mt. A total of 250 fertile eggs per treatment were collected, incubated, hatched, and sexed. Additional egg samples were analyzed for IgA and IgY contents. A total of 160 broiler chicks (80 ♀ and 80 ♂) from each breeder experimental group were placed in cages based on sex and BW resulting in 32 cages for each BB treatment group. Cages (16 per BB treatment group) were allocated to basal broiler chick diet or basal diet supplemented with 500 g of YB/Mt. On day 9, half of each BB by broiler chick dietary treatments was challenged with 1 mL of Eimeria culture (100,000 oocysts of Eimeria acervulina and 25,000 oocysts of Eimeria maxima). On day 14, all birds were necropsied for intestinal lesion scores and samples. Feeding YB to BB increased (P < 0.05) IgA concentration in egg yolk. Eimeria challenge decreased (P < 0.05) pancreas weight, jejunal villus height (VH), and growth performance but increased spleen weight, intestinal mass and jejunal mucosa IgA concentration. Independent of Eimeria challenge, feeding YB to BB and/or to chicks resulted in higher (P < 0.001) jejunal VH compared with feeding it to BB only or not at all. In conclusion, Eimeria challenge reduced growth performance and had negative effects on indices of intestinal function and health. Feeding YB to BB increased deposition of IgA in hatching eggs and improved jejunal VH independent of Eimeria challenge when fed to BB and/or to broiler chicks.

Microbiome and pathogen interaction with the immune system

The intestinal tract harbors a diverse community of microbes that have co-evolved with the host immune system. Although many of these microbes execute functions that are critical for host physiology, the host immune system must control the microbial community so that the dynamics of this interdependent relationship is maintained. To facilitate host homeostasis, the immune system ensures that the microbial load is tolerated, but anatomically contained, while remaining reactive to microbial invasion. Although the microbiota is required for intestinal immune development, immune responses regulate the structure and composition of the intestinal microbiota by evolving unique immune adaptations that manage this high-bacterial load. The immune mechanisms work together to ensure that commensal bacteria rarely breach the intestinal barrier and that any that do invade should be killed rapidly to prevent penetration to systemic sites. The communication between microbiota and the immune system is mediated by the interaction of bacterial components with pattern recognition receptors expressed by intestinal epithelium and various antigen-presenting cells resulting in activation of both innate and adaptive immune responses. Interaction between the microbial community and host plays a crucial role in the mucosal homeostasis and health status of the host. In addition to providing a home to numerous microbial inhabitants, the intestinal tract is an active immunological organ, with more resident immune cells than anywhere else in the body, organized in lymphoid structures called Peyer's patches and isolated lymphoid follicles such as the cecal tonsils. Macrophages, dendritic cells, various subsets of T cells, B cells and the secretory immunoglobulin A (IgA) they produce, all contribute to the generation of a proper immune response to invading pathogens while keeping the resident microbial community in check without generating an overt inflammatory response to it. IgA-producing plasma cells, intraepithelial lymphocytes, and γδT cell receptor-expressing T cells are lymphocytes that are uniquely present in the mucosa. In addition, of the γδT cells in the intestinal lamina propria, there are significant numbers of IL-17-producing T cells and regulatory T cells. The accumulation and function of these mucosal leukocytes are regulated by the presence of intestinal microbiota, which regulate these immune cells and enhance the mucosal barrier function allowing the host to mount robust immune responses against invading pathogens, and simultaneously maintains immune homeostasis.

Effect of in-ovo feeding of iron nanoparticles and methionine hydroxy analogue on broilers chickens small intestinal characteristics

The experiment was conducted with 644 Ross fertilized egg by 7 treatments 4 replicates and 23 eggs in each. Seven treatments included two control with and without injection, iron sulfate, iron sulfate nanoparticles, Alimet, Alimet + iron sulfate, Alimet + iron sulfate nanoparticles. After hatching 2 mg iron nanoparticles were applied as new treatment. The highest increased in the intestinal relative weight (p < 0.05) was observed by iron+Alimet in late feeding at day old of age. Also similar trend was found in cecum and duodenum length by iron control 2 and late feeding (18 hours’ after hatching). The highest cecum length was found among all treatments by in ovo injection of iron nanoparticles in early feeding at 21 days of age (p < 0.05). Significantly increased the duodenum length was found by iron sulfate in early feeding at 42 days of age (p < 0.05). In ovo injection of Alimet in late feeding was resulted in decrease jejunum crypt depth at 21 days of age (p < 0.05). The results of this study have shown that the highest jejunum villi width and surface area were recorded in dietary iron sulfate nanoparticles in late feeding at 21 and 42 days of age (p < 0.05).

Protected Blend of Organic Acids and Essential Oils Improves Growth Performance, Nutrient Digestibility, and Intestinal Health of Broiler Chickens Undergoing an Intestinal Challenge

The growing restriction of antibiotic growth promoters (AGP) use in farming animals has raised a concern regarding the viability of the animal production system. In this new context, feed additives with proven positive impact on intestinal health may be used as strategy to avoid losses on performance. The aim of this study was to evaluate the effects of a protected blend of organic acids and essential oils [P(OA+EO)] on growth performance, nutrient digestibility, and intestinal health of broiler chickens. A total of 1,080 Cobb × Cobb 500 male broilers were randomly distributed in four treatments with 10 replicates (27 birds/each). Treatments were as follow: non-challenged control; challenged control; AGP (enramycin at 10 g/t); and P(OA+EO) at 300 g/t. All birds on challenged groups were challenged with Eimeria spp. at 1 day and with Clostridium perfringens at 11, 12, and 13 days. Body weight gain (BWG), feed intake and feed conversion ratio (FCR) were evaluated until 42 days. At 17 days, one bird per pen was orally gavaged with fluorescein isothiocyanate-dextran (FITC-d) and blood samples were collected for FITC-d detection to assess intestinal permeability. At 21 days, apparent ileal nutrient and energy (IDE) digestibility, intestinal macroscopic and histologic alterations (ISI) and, expression of mucin2 (MUC2), claudin1 (CLDN1), and occludin (OCLN) genes in the jejunum were evaluated. From 1 to 42 days, birds from the non-challenged and P(OA+EO) groups had greater (P < 0.001) BWG compared to challenged control and AGP groups. The challenged control group presented the worst FCR (P < 0.001). IDE was 106 kcal/kg greater when broilers were fed P(OA+EO) compared to the challenged control group. Broilers supplemented with P(OA+EO) had improved intestinal integrity with lower blood FITC-d concentration and ISI scores, and greater expression of MUC2, CLDN1, and OCLN genes compared to the challenged control group (P < 0.05). In conclusion, the P(OA+EO) and the AGP led to increased growth performance, nutrient digestibility and intestinal health of challenged broilers. A marked difference occurred in favor of the P(OA+EO), suggesting that this blend may be used to improve intestinal health and broiler growth performance in AGP free programs.

Utility of Feed Enzymes and Yeast Derivatives in Ameliorating Deleterious Effects of Coccidiosis on Intestinal Health and Function in Broiler Chickens

Coccidiosis induced necrotic lesions impair digestive capacity and barrier function in concurrence with increased risks for secondary bacterial infections. The industry has been successful in controlling coccidiosis with anticoccidials and vaccination. However, concerns over Eimeria species resistant to anticoccidials, gaps in vaccination and restriction on antibiotics is stimulating research and application of alternative and/or complimentary strategies for coccidiosis control. The aim of this paper is to appraise literature on the utility of feed enzymes and yeast derivatives in modulating coccidiosis. Feed enzymes can complement endogenous enzymes (protease, amylase, and lipase) that may become insufficient in coccidiosis afflicted birds. Coccidiosis in the upper small intestine creates conditions that enhances efficacy of phytase and there are reports indicating supplemental phytase can mitigate the negative impact of coccidiosis on bone quality. Increase in intestinal short chain fatty acids due supplemental fiber degrading enzymes has been linked with reduced survivability of Eimeria. There is evidence whole yeast (live or dead) and derivatives can modulate coccidiosis. Immunomudulation properties of the yeast derivatives have been shown to enhance cellular and humoral immunity in Eimeria challenge models which is critical for effectiveness of coccidial vaccination. Moreover, yeast nucleotides have been shown to be beneficial in stimulating healing of intestinal mucosal surface. Other novel work has shown that certain yeast cells can produce derivatives with anticoccidial compounds effective in attenuating oocysts shedding. Yeast cell surface has also been shown to be an effective oral Eimeria vaccine delivery vehicle. Overall, while further refinement research is warranted to address inconsistencies in responses and commercial application, there is evidence feed enzymes and yeast derivatives could complement strategies for maintaining intestinal function to bolster growth performance in broilers compromised with coccidiosis. However, broilers receive diets containing several feed additives with distinct mode of actions and yet there is dearth of empirical data on the expected responses.Future evaluations should consider combinations of additives to document animal responses and potential synergies.

An immunomodulatory feed additive enhances in vitro viral vaccine recall antigen responses in dairy heifers

Enhancing immunological responses to vaccination is an important goal in many herd health management systems. OmniGen-AF®(OG) is an immunomodulatory feed additive that has been shown to enhance innate immune function in ruminants and its effects on adaptive immunity require additional study. The objective of this study was to evaluate post-vaccine antibody titers and circulating cellular memory development in heifers fed OG and administered a commercially available modified-live bovine respiratory disease (BRD) vaccine. Twenty-four Holstein heifers were assigned to one of two diets for 170 days: Control TMR (CON; n = 11), or TMR plus OG (TRT; 9 g/100 kg BW/day; n = 13). Samples for hematology, serology, and cellular assays were collected on D-110, 0, 21, 42, and 60 of the trial. Heifers were administered two priming doses of a modified-live BRD vaccine, with a third dose given on D0. There were no significant differences in total WBC and absolute number or the percentage of circulating lymphocytes, monocytes, neutrophils, RBC, or platelets on D-110 through D21. On D42 and D60, CON had significantly higher numbers of lymphocytes. On D0, mean serum neutralizing (SN) titer to BHV-1 was significantly higher for CON compared to TRT. SN titers were not significantly different between CON and TRT at any other time point for BHV-1, BVDV type 1, or BVDV type 2. TRT mounted a significantly stronger recall proliferative response to 0.5 multiplicity of infection (MOI) of BHV-1, BVDV type 1 and BVDV type 2 on D42 and D60; 0.25 MOI of BVDV type 1 on D21 and D42; and 0.25 MOI BVDV type 2 on D42 compared to CON. IL-4 production induced by 0.5 and 1.0 MOI BHV-1 (D42 and D60); 0.25 MOI of BVDV type 1 (D21); and 0.25 and 0.5 MOI of BVDV type 2 (D60) were significantly higher for TRT than CON. IL-17 production induced by 0.25 MOI of BVDV type 1 was significantly higher on D60 for TRT compared to CON. IFN-gamma and IL-10 were not significantly different between treatments. These data indicate feeding OG has a beneficial effect on responses to vaccine antigens in Holstein dairy heifers.

Effect of functional oils on the immune response of broilers challenged with Eimeria spp

Infection with Eimeria sp. results in the activation of multiple facets of the host immune system; the use of phytogenics can modulate the inflammatory response and improve the performance of the challenged animal. The aim of this study was to evaluate the effect of a commercial blend of cashew nut shell liquid (CNSL) and castor oil on the immune response of broilers challenged with coccidiosis. A total of 864 one-day-old male chicks (Cobb 500) were randomly distributed into six treatment groups (8 pens/treatment and 18 chicks/pen) in a three-by-two factorial design with three additives: control (non-additive), 100 ppm of monensin or 0.15% CNSL-castor oil. Challenge status was determined twice at 14 days of age. Unchallenged birds were inoculated by gavage with oocysts sporulated with Eimeria tenella, Eimeria acervulina and Eimeria maxima. Although the positive control (non-additive and challenged) and CNSL-castor oil treatment groups exhibited similar variation in weight gain (ΔBWG) compared to unchallenged birds fed without additives, the variation observed in birds fed diets containing CNSL-castor oil was associated with a higher maintenance requirement and not feed efficiency. In the second week after infection, ΔBWG of the CNSL-castor oil treatment group did not significantly change compared to the other treatment groups. At days 7 and 14 post-challenge, there was a higher excretion of oocysts in the control group, whereas the CNSL-castor oil and monensin groups did not differ. The CNSL-castor oil group exhibited increased gene expression of interferon (IFN), interleukin 6 (IL-6) and tumor necrosis factor (TNF), while the control group exhibited increased expression of cyclooxygenase (COX) and IL-1. The heterophils/lymphocyte ratio was low for the monensin treatment group. The unchallenged birds that received monensin treatment presented higher gene expression of IFN, COX and IL-1 compared to the other treatments, while the CNSL-castor oil group exhibited reduced gene expression, except for TNF. The commercial blend of cashew nut liquid and castor oil modulated the inflammatory response against Eimeria spp. In the absence of the parasite, there was no stimulation of genes involved in the inflammatory response, demonstrating that the blend is an effective tool in specifically modulating the immune system of birds afflicted with coccidiosis.

Applying I see inside histological methodology to evaluate gut health in broilers challenged with Eimeria

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The ISI was applied to evaluate histologic alterations specific of Eimeria infection.

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The ISI histological score show high correlation with broilers performance.

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The higher the ISI scores the worse are the performance results of birds challenged.

The present study evaluated the effects of coccidiosis on histological parameters and performance of broilers submitted to a mild challenge with Eimeria sp. A total of 132 broilers were randomly divided into two groups with 6 replicates of 11 birds each: negative control (NC) – birds uninfected and challenge (CH) - birds infected by gavage at day-one with 10x the manufacturer recommended dose of Bio-Coccivet R^® live vaccine by Biovet, with strains of E. acervulina, E. brunetti, E. maxima, E. necatrix, E. praecox, E. tenella and E. mitis. From 1 to 28 d of age, weekly the zootechnical performance was evaluated and samples of the liver, duodenum, jejunum and ileum were collected and submitted to histological analysis by the I See Inside methodology (ISI). The ISI methodology is a metric evaluation of histological alterations in the intestine and liver. Which translates macroscopic and microscopic alterations into numbers and allows their correlation with the animal zootechnical performance. Pearson’s correlation was used to demonstrates how the damages to the gut, evaluated by ISI method, could affect negatively the performance of broilers. The presence of oocysts in histological analysis of the jejunum and ileum at 7d indicate a negative effect on performance over the next 2 weeks (14d and 21d). When the ISI total score was measured in the ileum at 14d, we observed a strong negative effect on zootechnical performance from that period on 14d, 21d and 28d. The obtained data demonstrates that the higher the ISI scores, the worse are the zootechnical performance results of broilers challenged with Eimeria sp. and the I See Inside scores could be applied to evaluate coccidiosis effect on performance in future.

Histological parameters to evaluate intestinal health on broilers challenged with Eimeria and Clostridium perfringens with or without enramycin as growth promoter

The maintenance of integrity of the gastrointestinal tract is an important aspect for animal productivity, since it is able to absorb nutrients more efficiently and serves as a barrier against microorganisms. To control agents detrimental to intestinal integrity, growth-promoting antibiotics (AGP) are used, which reduce the number of toxin-producing microorganisms in the intestinal lumen, acting as anti-inflammatory agents. There is a demand for restriction of use of AGP in animal feed, but there are few studies showing what parameters we should observe to search for alternative additives. The aim of this study was to establish histological parameters that explain the effect of enramycin as growth promoter on intestinal health in broilers challenged with Eimeria and Clostridium perfringens. The zootechnical performance and the histology by I See Inside (ISI) methodology were evaluated on liver and ileum samples. Chickens challenged without AGP have the worst BWG, FCR, and histological ISI score (ISI score 9) in the ileum compared to non-challenged (ISI score 5). The use of enramycin on challenged group significantly minimized the ISI score in the ileum at 21 and 28 d (ISI score 7.4 and 8.0, respectively) compared with the challenged group not fed with enramycin (ISI score 9.2 and 9.9, respectively), associated with reduced lamina propria thickness and inflammatory cell infiltration. We suggest these 2 histological parameters as a standard to compare products for gut health.

Effect of aflatoxin experimental ingestion and Eimeira vaccine challenges on intestinal histopathology and immune cellular dynamic of broilers: applying an Intestinal Health Index

The present study evaluated the effect of aflatoxin B1 and Eimeria vaccine challenges and their interaction on intestinal morphology, applying the morphometric index "I See Inside" (ISI). Immune cellular response and broiler chicken performance were also studied. A total of 240 broiler chickens were divided in a 2 × 2 factorial arrangement with 4 treatments, T1: Control diet and no challenge (CON), T2: Aflatoxin B1 (AFLA), T3: Control diet and Eimeria challenge (COC), and T4: Aflatoxin B1 and Eimeria challenge (AFLA+COC). The mathematical morphometric index ISI was applied to evaluate macro and microscopic alterations. Samples of liver and jejunum were analyzed for macrophages, CD4+, and CD8+ cells counting by immunohistochemistry at 7, 14, and 21 d of age. Chickens challenged with Eimeria presented higher ISI of macroscopic alterations associated to Eimeria lesion at the medium small intestine, lower body weight gain (BWG) and feed intake (FI), and worse feed conversion ratio compared to non-challenged birds. Both Eimeria and aflatoxin challenges modulated the immune cells in the jejunum and liver, generally increasing the number of macrophages, CD4+, and CD8+ cells in relation to the control group. Birds from COC and COC+AFLA groups presented higher ISI histological score in the jejunum at 7 and 14 d of age compared to the CON and AFLA groups. The reduction of FI and BWG was correlated to high histological ISI and resulted in a high presence of immune cells in tissues, suggesting immune response demand. The histological ISI had statistical correlation to broiler performance.

Landscape genomics: natural selection drives the evolution of mitogenome in penguins

Background

Mitochondria play a key role in the balance of energy and heat production, and therefore the mitochondrial genome is under natural selection by environmental temperature and food availability, since starvation can generate more efficient coupling of energy production. However, selection over mitochondrial DNA (mtDNA) genes has usually been evaluated at the population level. We sequenced by NGS 12 mitogenomes and with four published genomes, assessed genetic variation in ten penguin species distributed from the equator to Antarctica. Signatures of selection of 13 mitochondrial protein-coding genes were evaluated by comparing among species within and among genera (Spheniscus, Pygoscelis, Eudyptula, Eudyptes and Aptenodytes). The genetic data were correlated with environmental data obtained through remote sensing (sea surface temperature [SST], chlorophyll levels [Chl] and a combination of SST and Chl [COM]) through the distribution of these species.

Results

We identified the complete mtDNA genomes of several penguin species, including ND6 and 8 tRNAs on the light strand and 12 protein coding genes, 14 tRNAs and two rRNAs positioned on the heavy strand. The highest diversity was found in NADH dehydrogenase genes and the lowest in COX genes. The lowest evolutionary divergence among species was between Humboldt (Spheniscus humboldti) and Galapagos (S. mendiculus) penguins (0.004), while the highest was observed between little penguin (Eudyptula minor) and Adélie penguin (Pygoscelis adeliae) (0.097). We identified a signature of purifying selection (Ka/Ks < 1) across the mitochondrial genome, which is consistent with the hypothesis that purifying selection is constraining mitogenome evolution to maintain Oxidative phosphorylation (OXPHOS) proteins and functionality. Pairwise species maximum-likelihood analyses of selection at codon sites suggest positive selection has occurred on ATP8 (Fixed-Effects Likelihood, FEL) and ND4 (Single Likelihood Ancestral Counting, SLAC) in all penguins. In contrast, COX1 had a signature of strong negative selection. ND4 Ka/Ks ratios were highly correlated with SST (Mantel, p-value: 0.0001; GLM, p-value: 0.00001) and thus may be related to climate adaptation throughout penguin speciation.

Conclusions

These results identify mtDNA candidate genes under selection which could be involved in broad-scale adaptations of penguins to their environment. Such knowledge may be particularly useful for developing predictive models of how these species may respond to severe climatic changes in the future.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4424-9) contains supplementary material, which is available to authorized users.

Growth performance and gastrointestinal responses of broiler chickens fed corn-soybean meal diet without or with exogenous epidermal growth factor upon challenge with Eimeria

Epidermal growth factor (EGF), a protein known for its mitogenic and anti-apoptotic effects was fed to broiler chickens to evaluate growth performance, gastrointestinal measurements, and apparent retention (AR) of components upon challenge with Eimeria. A total of 216, d old male broiler chicks (Ross 708) were placed in cages (6 birds/cage) and allocated to treatments. The treatments were: 1) control (Lactotobacilli lactis fermentation supernatant without EGF), 2) 80 μg of EGF/kg BW/d, and 3) 160 μg of EGF/kg BW/d. A basal antibiotic-free corn-soybean diet containing TiO2 was used. Birds were offered fresh feed with respective treatments on daily basis and had free access to drinking water for 14 d. On d 5, birds (6 replicates per treatment) were challenged with 1 mL of E. acervulina and E. maxima mixture via oral gavage and the other 6 replicates were given sham. Growth performance was measured in pre- (d 0 to 5) and post- (d 6 to 14) challenge periods. Two birds per cage were necropsied on d 10 for intestinal lesion scores and tissue samples for histomorphology and expression of select intestinal genes. Excreta samples for AR of components and oocyst shedding were taken d 10 to 13 and all birds were necropsied on d 14 for gastrointestinal weight. The EGF linearly (P < 0.05) increased BWG before challenge. There was no EGF and Eimeria interaction (P > 0.05) on growth performance, AR of GE, and intestinal histomorphology; the main effects were such that Eimeria depressed (P < 0.01) BWG, FCR, AR of DM, crude fat, and GE, and villi height to crypt depth ratio. An interaction between EGF and Eimeria (P < 0.05) on indices of gut function was such that EGF improved expression of genes for nutrient transporters and tight junction proteins in Eimeria challenged birds whilst no effect in non-challenged control. In conclusion, Eimeria challenge reduced growth performance and impaired gut function; EGF showed beneficial effects on growth pre-challenge and improved indices of gut function upon Eimeria challenge.

Effects of Diet Restriction and Diet Complexity on Life History Strategies in Side-Blotched Lizards (Uta stansburiana)

Organisms must balance energy invested into self-maintenance, reproduction, and somatic growth over their lifetime. In this study, the effects of diet restriction and diet complexity on side-blotched lizards (Uta stansburiana) were analyzed. Thirty male lizards, housed in the laboratory, were fed either an ad libitum or a restricted diet for 18 days (phase 1). Individuals from both treatments were then assigned to a diet of the same quantity of food that was either simple (only crickets) or complex (crickets, cockroaches, waxworms, and mealworms) for 35 days (phase 2). We evaluated (1) how diet restriction affected life history strategies and (2) how diet complexity affected recovery from diet restriction as measured at the end of phase 2 by body mass, snout-vent length, calculated body condition score, wound healing, tail regrowth, bacterial killing ability, oxidative stress, and plasma testosterone and corticosterone concentrations. Lizards without diet restriction allocated more energy to self-maintenance (i.e., maintaining higher body condition scores, healing wounds more quickly) than lizards with diet restriction. Lizards with diet restriction had higher plasma testosterone concentrations and larger increases in snout-vent lengths than those fed ad libitum, which may reflect allocations toward reproduction and somatic growth. A complex diet resulted in better body condition and faster tail regrowth than a simple diet, suggesting that a complex diet enhanced recovery from diet restriction, although long-term life history choices remained unaltered. Finally, lizards on a complex diet consumed substantially less food while maintaining higher body condition, suggesting that key nutrients may be lacking from a simple diet.

Immunomodulation in young laying hens by dietary folic acid and acute immune responses after challenge with Escherichia coli lipopolysaccharide

We investigated the effects of dietary folic acid (FA) supplementation on immunological parameters in young laying hens under acute conditions of lipopolysaccharide (LPS) challenge. Twenty-four Shaver White laying hens at 24 wk were fed 2 diets in a completely randomized design. The diets were wheat-soybean based, with either 0 or 4 mg of supplemental FA per kilogram of diet. At 32 wk of age, 6 hens from each dietary treatment were injected intravenously with 8 mg/kg of BW of either LPS or saline. Four hours after injection, blood was collected and the hens were euthanized to obtain spleen and cecal tonsils. Heterophil:lymphocyte ratio, CD3+, CD4+, CD8+ T cells, and CD4+:CD8+ cells in the blood and spleen were not affected by dietary FA. Relative to saline-injected hens, LPS-injected hens had fewer (P < 0.05) CD3+, CD4+, CD8+, and CD4+:CD8+ cells in the blood, and no difference was found in the spleen. Total protein, albumin, and globulin were found to be higher (P < 0.05) in FA-supplemented hens compared with the control. However, total protein, albumin, and globulins decreased (P < 0.05) in the LPS-injected hens compared with the saline control. Expression of interleukin (IL)-1β in cecal tonsils decreased (P < 0.05) in FA-supplemented hens, but no dietary influence was found on the expression of other genes in both the spleen and cecal tonsils. Lipopolysaccharide upregulated (P < 0.05) expression of IL-10 and interferon (IFN)-γ in the spleen, and IL-1β, IL-10, and IFN-γ in the cecal tonsils, whereas the expression of Toll-like receptor (TLR)-4 and IL-8 was not influenced by LPS in the spleen and cecal tonsils. There was a diet × challenge interaction for total IgG, and cytokines IL-1β and IL-18 in the spleen as well as IL-18 in the cecal tonsils. In conclusion, there were few interactions of dietary FA and LPS; however, FA increased biochemical constituents, enhanced generation of total IgG, as well as exhibiting pleoitropic effects in inflammatory responses.

Modulation of post-hatch growth and immunity through in ovo supplemented nutrients in broiler chickens

BACKGROUND

Early post-hatch growth and immunity were assessed through in ovo supplementation of nutrients: amino acids (AA), trace elements (TE), fatty acids and vitamins (FAV) grouped under humoral immunity (HI) or cell-mediated immunity (CMI) on the 18th day of incubation at the broad end of the egg using a 25 mm needle.

RESULTS

Hatchability in AA groups was better than TE and FAV groups. CMI groups had better hatchability than HI groups. AA and TE groups had higher chick-to-egg weight ratio (P < 0.01) than the FAV group. At 3 weeks of age, a higher body weight (P < 0.01) was recorded in AA for CMI, TE for HI and FAV for HI groups. FAV-injected chicks had a higher bursa weight at hatch, but TE chicks had higher thymus weight at the 3rd week of age. Humoral immune response was not different in in ovo injected chicks compared to control. CMI was higher (P < 0.01) in AA for CMI, TE for CMI and FAV for CMI or HI nutrient-injected chicks.

CONCLUSIONS

In ovo injection of AA for CMI and TE for HI may accelerate growth of broiler chickens. In ovo injection of AA, TE or FAV may modulate CMI in chicks.

Gene expression profiling of the local cecal response of genetic chicken lines that differ in their susceptibility to Campylobacter jejuni colonization

Campylobacter jejuni (C. jejuni) is one of the most common causes of human bacterial enteritis worldwide primarily due to contaminated poultry products. Previously, we found a significant difference in C. jejuni colonization in the ceca between two genetically distinct broiler lines (Line A (resistant) has less colony than line B (susceptible) on day 7 post inoculation). We hypothesize that different mechanisms between these two genetic lines may affect their ability to resist C. jejuni colonization in chickens. The molecular mechanisms of the local host response to C. jejuni colonization in chickens have not been well understood. In the present study, to profile the cecal gene expression in the response to C. jejuni colonization and to compare differences between two lines at the molecular level, RNA of ceca from two genetic lines of chickens (A and B) were applied to a chicken whole genome microarray for a pair-comparison between inoculated (I) and non-inoculated (N) chickens within each line and between lines. Our results demonstrated that metabolism process and insulin receptor signaling pathways are key contributors to the different response to C. jejuni colonization between lines A and B. With C. jejuni inoculation, lymphocyte activation and lymphoid organ development functions are important for line A host defenses, while cell differentiation, communication and signaling pathways are important for line B. Interestingly, circadian rhythm appears play a critical role in host response of the more resistant A line to C. jejuni colonization. A dramatic differential host response was observed between these two lines of chickens. The more susceptible line B chickens responded to C. jejuni inoculation with a dramatic up-regulation in lipid, glucose, and amino acid metabolism, which is undoubtedly for use in the response to the colonization with little or no change in immune host defenses. However, in more resistant line A birds the host defense responses were characterized by an up-regulation lymphocyte activation, probably by regulatory T cells and an increased expression of the NLR recognition receptor NALP1. To our knowledge, this is the first time each of these responses has been observed in the avian response to an intestinal bacterial pathogen.