Bacterial clearance, heterophil function, and hematological parameters of transport-stressed turkey poults supplemented with dietary yeast extract

Oligodeoxynucleotides containing CpG motifs upregulate bactericidal activities of heterophils and enhance immunoprotection of neonatal broiler chickens against Salmonella Typhimurium septicemia

In the past, we demonstrated that oligodeoxynucleotides containing CpG motifs (CpG-ODN) mimicking bacterial DNA, stimulate the innate immune system of neonatal broiler chickens and protect them against Escherichia coli and Salmonella Typhimurium (S. Typhimurium) septicemia. The first line of innate immune defense mechanism is formed by heterophils and plays a critical protective role against bacterial septicemia in avian species. Therefore, the objectives of this study were 1) to explore the kinetics of CpG-ODN mediated antibacterial mechanisms of heterophils following single or twice administration of CpG-ODN in neonatal broiler chickens and 2) to investigate the kinetics of the immunoprotective efficacy of single versus twice administration of CpG-ODN against S. Typhimurium septicemia. In this study, we successfully developed and optimized flow cytometry-based assays to measure phagocytosis, oxidative burst, and degranulation activity of heterophils. Birds that received CpG-ODN had significantly increased (p < 0.05) phagocytosis, oxidative burst, and degranulation activity of heterophils as early as 24 h following CpG-ODN administration. Twice administration of CpG-ODN significantly increased the phagocytosis activity of heterophils. In addition, our newly developed CD107a based flow cytometry assay demonstrated a significantly higher degranulation activity of heterophils following twice than single administration of CpG-ODN. However, the oxidative burst activity of heterophils was not significantly different between birds that received CpG-ODN only once or twice. Furthermore, delivery of CpG-ODN twice increased immunoprotection against S. Typhimurium septicemia compared to once but the difference was not statistically significant. In conclusion, we demonstrated enhanced bactericidal activity of heterophils after administration of CpG-ODN to neonatal broiler chickens. Further investigations will be required to identify other activated innate immune cells and the specific molecular pathways associated with the CpG-ODN mediated activation of heterophils.

Induction of trained immunity in broiler chickens following delivery of oligodeoxynucleotide containing CpG motifs to protect against Escherichia coli septicemia

Oligodeoxynucleotides containing CpG motifs (CpG-ODN) can promote antimicrobial immunity in chickens by enriching immune compartments and activating immune cells. Innate memory, or trained immunity, has been demonstrated in humans and mice, featuring the absence of specificity to the initial stimulus and subsequently cross-protection against pathogens. We hypothesize that CpG-ODN can induce trained immunity in chickens. We delivered single or multiple administrations of CpG-ODN to birds and mitochondrial oxidative phosphorylation (OXPHOS) and glycolysis of peripheral blood mononuclear cells were quantified using Seahorse XFp. Next, chickens were administered with CpG-ODN twice at 1 and 4 day of age and challenged with Escherichia coli at 27 days of age. The CpG-ODN administered groups had significantly higher mitochondrial OXPHOS until 21 days of age while cellular glycolysis gradually declined by 14 days of age. The group administered with CpG-ODN twice at 1 and 4 days of age had significantly higher survival, lower clinical score and bacterial load following challenge with E. coli at 27 d of age. This study demonstrated the induction of trained immunity in broiler chickens following administration of CpG-ODN twice during the first 4 days of age to protect birds against E. coli septicemia at 27 days of age.

Impact of β-glucan dietary supplementation on productive, reproductive performance and physiological response of laying hens under heat stress conditions

The exploration for effective in-feed additives is growing owing to the global climatic change trend to alleviate the negative effects of heat stress in laying hens. This research assessed the potential of using B-glucan (G) as an antiheat stress agent in Matrouh laying hens subjected to early heat shock programs during the growing period. Factorial design (3 × 3) was used, including 3 levels of heat stress (control, heat shock at 3 d and at 3 d and 8 wk of age) and 3 levels of β-glucan (0, 100, and 200 mg β-glucan /kg diet). During the first 12 wk of egg production (EP), treatments were exposed to heat challenge. The results revealed that heat shock program applications at 3 d and 8 wk of age significantly decreased body weight at 36 wk of age (P < 0.05) and reduced (P < 0.05) feed intake (FI). While significantly (P < 0.05) improved feed conversion ratio (FCR), hemoglobin, RBCs, WBCs, immunoglobulin M (IgM), immunoglobulin G (IgG), and Heat shock protein (HSP70) of the Liver (P < 0.01) as compared with the control group. At the same time, there was a decrease in lymphocyte%, H/L ratio, cortisol, and T3 compared to the thermo-neutral control. When compared to the control group, hens fed a diet containing 200 mg of βG significantly (P < 0.05) improved body weight at 16 wk and final weight at 36 wk, feed conversion (FCR) (g. feed/g. egg mass), hen-day egg production, and egg mass, as well as the digestibility coefficients of crude protein (CP), dry matter (DM), metabolizable energy (ME), and cortisol. The interactions between heat chock programs and βG levels were nonsignificant for the most studied traits except daily feed intake. Therefore, the early heat shock exposure 2 times and supplementation of Β-glucan (βG) at 200 mg/kg diet during the growth period for laying hens that are exposed to heat stress during the reproductive period could improve productive, reproductive performance, HSP70 level and enhance immunity responses.

Preventing bacterial disease in poultry in the post-antibiotic era: a case for innate immunity modulation as an alternative to antibiotic use

The widespread use of antibiotics in the poultry industry has led to the emergence of antibiotic-resistant bacteria, which pose a significant health risk to humans and animals. These public health concerns, which have led to legislation limiting antibiotic use in animals, drive the need to find alternative strategies for controlling and treating bacterial infections. Modulation of the avian innate immune system using immunostimulatory compounds provides a promising solution to enhance poultry immune responses to a broad range of bacterial infections without the risk of generating antibiotic resistance. An array of immunomodulatory compounds have been investigated for their impact on poultry performance and immune responses. However, further research is required to identify compounds capable of controlling bacterial infections without detrimentally affecting bird performance. It is also crucial to determine the safety and effectiveness of these compounds in conjunction with poultry vaccines. This review provides an overview of the various immune modulators known to enhance innate immunity against avian bacterial pathogens in chickens, and describes the mechanisms involved.

Dietary 1,3-β-Glucans Affect Growth, Breast Muscle Composition, Antioxidant Activity, Inflammatory Response, and Economic Efficiency in Broiler Chickens

Recently, researchers have been intensively looking for novel, safe antibiotic alternatives because of the prevalence of many clinical and subclinical diseases affecting bird flocks and the risks of using antibiotics in subtherapeutic doses as feed additives. The present study intended to evaluate the potential use of 1,3-β-glucans (GLC) as antibiotic alternative growth promotors and assessed the effect of their dietary inclusion on the growth performance, carcass traits, chemical composition of breast muscles, economic efficiency, blood biochemical parameters, liver histopathology, antioxidant activity, and the proinflammatory response of broiler chickens. This study used 200 three-day-old ROSS broiler chickens (50 chicks/group, 10 chicks/replicate, with an average body weight of 98.71 ± 0.17 g/chick). They were assigned to four experimental groups with four dietary levels of GLC, namely 0, 50, 100, and 150 mg kg−1, for a 35-day feeding period. Birds fed diets containing GLC showed an identical different growth rate to the control group. However, the total feed intake (TFI) increased quadratically in the GLC50 and GLC100 groups as compared to that in the control group. GLC addition had no significant effect on the weights of internal and immune organs, except for a decrease in bursal weight in the GLC150 group (p = 0.01). Dietary GLC addition increased the feed cost and total cost at 50 and 100 mg kg−1 doses. The percentages of n-3 and n-6 PUFA in the breast muscle of broiler chickens fed GLC-supplemented diets increased linearly in a dose-dependent manner (p < 0.01). The serum alanine aminotransferase (ALT) level and the uric acid level were quadratically increased in the GLC150 group. The serum levels of total antioxidant capacity, catalase, superoxide dismutase, interleukin-1β, and interferon-gamma linearly increased, while the MDA level decreased in the GLC-fed groups in a dose-dependent manner. Normal histological characterization of different liver structures in the different groups with moderate round cells was noted as a natural immune response around the hepatic portal area. The different experimental groups showed an average percentage of positive immunostaining to the proinflammatory marker transforming growth factor-beta with an increase in the dose of GLC addition. The results suggest that GLC up to 100 mg kg−1 concentration can be used as a feed additive in the diets of broiler chickens and shows no adverse effects on their growth, dressing percentage, and internal organs. GLC addition in diets improves the antioxidant activity and immune response in birds. GLC help enrich the breast muscle with n-3 and n-6 polyunsaturated fatty acids.

Yeast Extract: Characteristics, Production, Applications and Future Perspectives

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

From Cancer Therapy to Winemaking: The Molecular Structure and Applications of β-Glucans and β-1, 3-Glucanases

β-glucans are a diverse group of polysaccharides composed of β-1,3 or β-(1,3-1,4) linked glucose monomers. They are mainly synthesized by fungi, plants, seaweed and bacteria, where they carry out structural, protective and energy storage roles. Because of their unique physicochemical properties, they have important applications in several industrial, biomedical and biotechnological processes. β-glucans are also major bioactive molecules with marked immunomodulatory and metabolic properties. As such, they have been the focus of many studies attesting to their ability to, among other roles, fight cancer, reduce the risk of cardiovascular diseases and control diabetes. The physicochemical and functional profiles of β-glucans are deeply influenced by their molecular structure. This structure governs β-glucan interaction with multiple β-glucan binding proteins, triggering myriad biological responses. It is then imperative to understand the structural properties of β-glucans to fully reveal their biological roles and potential applications. The deconstruction of β-glucans is a result of β-glucanase activity. In addition to being invaluable tools for the study of β-glucans, these enzymes have applications in numerous biotechnological and industrial processes, both alone and in conjunction with their natural substrates. Here, we review potential applications for β-glucans and β-glucanases, and explore how their functionalities are dictated by their structure.

Potential Replacements for Antibiotic Growth Promoters in Poultry: Interactions at the Gut Level and Their Impact on Host Immunity

The chicken gastrointestinal tract (GIT) has a complex, biodiverse microbial community of ~ 9 million bacterial genes plus archaea and fungi that links the host diet to its health. This microbial population contributes to host physiology through metabolite signaling while also providing local and systemic nutrients to multiple organ systems. In a homeostatic state, the host-microbial interaction is symbiotic; however, physiological issues are associated with dysregulated microbiota. Manipulating the microbiota is a therapeutic option, and the concept of adding beneficial bacteria to the intestine has led to probiotic and prebiotic development. The gut microbiome is readily changeable by diet, antibiotics, pathogenic infections, and host- and environmental-dependent events. The intestine performs key roles of nutrient absorption, tolerance of beneficial microbiota, yet responding to undesirable microbes or microbial products and preventing translocation to sterile body compartments. During homeostasis, the immune system is actively preventing or modulating the response to known or innocuous antigens. Manipulating the microbiota through nutrition, modulating host immunity, preventing pathogen colonization, or improving intestinal barrier function has led to novel methods to prevent disease, but also resulted in improved body weight, feed conversion, and carcass yield in poultry. This review highlights the importance of adding different feed additives to the diets of poultry in order to manipulate and enhance health and productivity of flocks.

Probiotics: an Antibiotic Replacement Strategy for Healthy Broilers and Productive Rearing

Pathogens develop resistance to antibiotics at a rate much faster than the discovery of new antimicrobial compounds. Reports of multidrug-resistant bacteria isolated from broilers, and the possibility that these strains may spread diseases amongst humans, prompted many European countries to ban the inclusion of antibiotics in feed. Probiotics added to broiler feed controlled a number of bacterial infections. A combination of Enterococcus faecium, Pediococcus acidilactici, Bacillus animalis, Lactobacillus salivarius and Lactobacillus reuteri decreased the colonisation of Campylobacter jejuni and Salmonella Enteritidis in the gastro-intestinal tract (GIT) of broilers, whereas Bacillus subtilis improved feed conversion, intestinal morphology, stimulated the immune system and inhibited the colonisation of Campylobacter jejuni, Escherichia coli and Salmonella Minnesota. Lactobacillus salivarius and Pediococcus parvulus improved weight gain, bone characteristics, intestinal morphology and immune response, and decreased the colonisation of S. Enteritidis. Lactobacillus crispatus, L. salivarius, Lactobacillus gallinarum, Lactobacillus johnsonii, Enterococcus faecalis and Bacillus amyloliquefaciens decreased the Salmonella count and led to an increase in lysozyme and T lymphocytes. Probiotics may also improve feed digestion through production of phytases, lipases, amylases and proteases or stimulate the GIT to secrete digestive enzymes. Some strains increase the nutritional value of feed by production of vitamins, exopolysaccharides and antioxidants. Bacteriocins, if produced, regulate pathogen numbers in the GIT and keep pro-inflammatory and anti-inflammatory reactions in balance.

Review: β-glucans as Effective Antibiotic Alternatives in Poultry

The occurrence of microbial challenges in commercial poultry farming causes significant economic losses. Antibiotics have been used to control diseases involving bacterial infection in poultry. As the incidence of antibiotic resistance turns out to be a serious problem, there is increased pressure on producers to reduce antibiotic use. With the reduced availability of antibiotics, poultry producers are looking for feed additives to stimulate the immune system of the chicken to resist microbial infection. Some β-glucans have been shown to improve gut health, to increase the flow of new immunocytes, increase macrophage function, stimulate phagocytosis, affect intestinal morphology, enhance goblet cell number and mucin-2 production, induce the increased expression of intestinal tight-junctions, and function as effective anti-inflammatory immunomodulators in poultry. As a result, β-glucans may provide a new tool for producers trying to reduce or eliminate the use of antibiotics in fowl diets. The specific activity of each β-glucan subtype still needs to be investigated. Upon knowledge, optimal β-glucan mixtures may be implemented in order to obtain optimal growth performance, exert anti-inflammatory and immunomodulatory activity, and optimized intestinal morphology and histology responses in poultry. This review provides an extensive overview of the current use of β glucans as additives and putative use as antibiotic alternative in poultry.

The Modulating Effect of Dietary Beta-Glucan Supplementation on Expression of Immune Response Genes of Broilers during a Coccidiosis Challenge

Simple Summary

Avian coccidiosis is the leading parasitic disease in the poultry industry and means to control its damages continue to be explored. This study evaluated the feeding effects of a yeast-derived β-glucan on expression of immune response genes in the spleen, thymus, and bursa of commercial broiler chickens during an Eimeria challenge. The study consisted of two dietary treatments (0% or 0.1% β-glucan) each with or without a coccidiosis challenge. There were significant effects from dietary β-glucan, Eimeria challenge, and their interaction for several gene targets in the spleen, thymus, and bursa on days 10 and 14 of age. Based on the current results, supplementation of dietary β-glucan in Eimeria-challenged birds enhanced and modulated the expression of immune response genes during coccidiosis.

Abstract

This study investigated the effects of a yeast-derived β-glucan (Auxoferm YGT) supplementation on mRNA expression of immune response genes in the spleen, thymus, and bursa of broiler chickens during a mixed Eimeria infection. Day (d)-old chicks (n = 1440) were fed diets containing 0% or 0.1% YGT. On d 8 post-hatch, half the replicate pens (n = 8) were challenged with a mixed inoculum of E. acervulina, E. maxima, and E. tenella. On d 10 and d 14 post-hatch, the spleen, thymus, and bursa were collected to evaluate mRNA abundance by quantitative real-time PCR. Data were analyzed using PROC GLIMMIX model (2-way interaction) and differences were established by LS-MEANS with significance reported at p ≤ 0.05. In spleen tissues at d 10, expression of interleukin (IL)-10 and inducible nitric oxide synthase (iNOS) were elevated in both 0.1% YGT-fed challenged and non-challenged birds. In thymus tissues at d 14, expression of IL-10, IL-17F, interferon (IFN)-γ, iNOS, and macrophage migration inhibitory factor (MIF) were elevated in challenged birds fed 0.1% YGT. In bursal tissues at d 10 and d 14, expression of IL-10, IFN-γ, iNOS (d 10 only), and MIF were elevated in 0.1% YGT-fed challenged and non-challenged birds. Dietary β-glucan supplementation to chicken diets modulated their immune response to the Eimeria challenge.

Physiological parameter values for physiologically based pharmacokinetic models in food-producing animals. Part II: Chicken and turkey

Physiologically based pharmacokinetic (PBPK) models are growing in popularity due to human food safety concerns and for estimating drug residue distribution and estimating withdrawal intervals for veterinary products originating from livestock species. This paper focuses on the physiological and anatomical data, including cardiac output, organ weight, and blood flow values, needed for PBPK modeling applications for avian species commonly consumed in the poultry market. Experimental and field studies from 1940 to 2019 for broiler chickens (1-70 days old, 40 g - 3.2 kg), laying hens (4-15 months old, 1.1-2.0 kg), and turkeys (1 day-14 months old, 60 g -12.7 kg) were searched systematically using PubMed, Google Scholar, ProQuest, and ScienceDirect for data collection in 2019 and 2020. Relevant data were extracted from the literature with mean and standard deviation (SD) being calculated and compiled in tables of relative organ weights (% of body weight) and relative blood flows (% of cardiac output). Trends of organ or tissue weight growth during different life stages were calculated when sufficient data were available. These compiled data sets facilitate future PBPK model development and applications, especially in estimating chemical residue concentrations in edible tissues to calculate food safety withdrawal intervals for poultry.

Innate Immunomodulation in Food Animals: Evidence for Trained Immunity?

Antimicrobial resistance (AMR) is a significant problem in health care, animal health, and food safety. To limit AMR, there is a need for alternatives to antibiotics to enhance disease resistance and support judicious antibiotic usage in animals and humans. Immunomodulation is a promising strategy to enhance disease resistance without antibiotics in food animals. One rapidly evolving field of immunomodulation is innate memory in which innate immune cells undergo epigenetic changes of chromatin remodeling and metabolic reprogramming upon a priming event that results in either enhanced or suppressed responsiveness to secondary stimuli (training or tolerance, respectively). Exposure to live agents such as bacille Calmette-Guerin (BCG) or microbe-derived products such as LPS or yeast cell wall ß-glucans can reprogram or "train" the innate immune system. Over the last decade, significant advancements increased our understanding of innate training in humans and rodent models, and strategies are being developed to specifically target or regulate innate memory. In veterinary species, the concept of enhancing the innate immune system is not new; however, there are few available studies which have purposefully investigated innate training as it has been defined in human literature. The development of targeted approaches to engage innate training in food animals, with the practical goal of enhancing the capacity to limit disease without the use of antibiotics, is an area which deserves attention. In this review, we provide an overview of innate immunomodulation and memory, and the mechanisms which regulate this long-term functional reprogramming in other animals (e.g., humans, rodents). We focus on studies describing innate training, or similar phenomenon (often referred to as heterologous or non-specific protection), in cattle, sheep, goats, swine, poultry, and fish species; and discuss the potential benefits and shortcomings of engaging innate training for enhancing disease resistance.

Effect of transportation and shackling on plasma concentrations of corticosterone and heterophil to lymphocyte ratios in market weight male turkeys in a commercial operation

There is limited information on the effects of stress and/or physiological manipulation on either plasma concentrations of corticosterone (CORT) and/or heterophil: lymphocyte (H : L) ratios in turkeys. The present studies examine the effects of catching/transportation/lairage in a holding shed and shackling on plasma concentrations of CORT and H : L ratios in male market weight turkeys. Plasma concentrations of CORT were increased after transportation and lairage but not further elevated by shackling, irrespective of its duration up to 240 s. In one study, there were increased H : L ratios following catching/placing birds into transportation cages/transportation/lairage. In one study, H : L ratios declined following shackling. It is concluded that while moving turkeys from the farm to immediately before the shackling line is stressful, shackling for up to 4 min was not perceived as more stressful in turkeys. There were also differences between farms/houses for both plasma concentrations of CORT and H : L ratios.

Evaluation of yeast culture and direct-fed microbial on gut histology and serum components of broilers challenged with suboptimal diets under heat stress

The use of antibiotics in feed for growth promotion has been restricted in many countries, thus it is of interest to investigate potential alternatives for enhancing growth performance in birds. An experiment was carried out to evaluate the concurrent use of prebiotic and probiotic on gut histology and some blood chemicals of broiler chickens during heat stress. A total of 144 day-old male Ross 308 broiler chicks were randomly divided into 3 treatments. The first treatment was a diluted diet including rice bran without probiotic or prebiotic. The other treatments were fed the diluted diets with a prebiotic (treatment 2) and concurrent use of that prebiotic along with a probiotic (treatment 3). Results showed that villus height was not influenced by feed additives. However, crypt depth significantly increased by feed additives in particular with combination of prebiotic and probiotic. The ratio of villus height to crypt depth significantly decreased in treatments fed prebiotic alone or prebiotic and probiotic together. This finding is indicating the fact that non-starch polysaccharides (NSPs) in high inclusion rate of rice bran caused to villus height erosion. It could be concluded that prebiotic and probiotic caused an increasing of enterocyte proliferation in the crypt of Liberkhun.

Evaluation of barley to replace milk by-product in weaning pig's diet

The supplementation level of barley was limited because of high contents of fiber in monogastric animals. Barley contained high soluble fiber, thus it could prevent to diarrhea of weaning pigs. Moreover, as the barley break down by enzymes, free sugars come out from the barley, which could be used as an energy source in weaning pigs and replace milk by-products in weaning pig’s diet. Therefore, present study was conducted to investigate the influence of barley to replace milk by-product in weaning pig’s diet on growth performance, blood profile, nutrient digestibility, diarrhea incidence, and economic analysis in weaning pigs. A total of 112 crossbred ([York-shire × Landrace] × Duroc, weaned at 28 days of age) piglets were allotted to 4 treatments in a randomized complete block (RCB) design. Each treatment has 7 replications with 4 pigs per pen. Pigs were fed each treatment diet which containing different levels of barley (0%, 10%, 20%, and 30%) at the expense of whey powder and lactose. Three phase feeding programs were used for 6 weeks of growth trial (phase 1: 0–2 weeks; phase 2: 3–4 weeks; phase 3: 5–6 weeks). During 0–2 week, body weight (BW), average daily gain (ADG) and G:F ratio were decreased as barley level increased in the diet (linear response, p < 0.01). In blood profile, blood urea nitrogen was decreased as the barley level increased in the diet (linear, p < 0.01). However, no significant differences were observed in blood glucose level. In nutrient digestibility, crude fat digestibility was linearly increased as barley increased (linear, p < 0.01). The incidence of diarrhea was improved as increasing barley contents in all phases (linear, p < 0.01). These results demonstrated that supplementation of barley to replace milk by-product influenced negatively on growth performance during 0–2 week. However, the incidence of diarrhea and later growth performance from 3 week postweaning were improved as dietary barley level increased.

Intrapulmonary Delivery of CpG-ODN Microdroplets Provides Protection Against Escherichia coli Septicemia in Neonatal Broiler Chickens

Synthetic oligodeoxynucleotides (ODN) containing unmethylated cytosine phosphodiester guanine (CpG) motifs (CpG-ODN) are effective immunostimulatory agents against a variety of viral, bacterial, and protozoan diseases in different animals including poultry. We have recently demonstrated that in ovo injection of CpG-ODN confers protection in neonatal chickens against bacterial septicemias. The objective of this study was to investigate the effectiveness of needle-free intrapulmonary (IPL) delivery of CpG-ODN microdroplets against Escherichia coli infection in neonatal chicks. In the present study, we used 880 chicks in total keeping 40 chicks per group. Chicks were delivered CpG-ODN or saline by IPL at the day 1 of hatch. Three days later, chicks were challenged with two doses (1 × 10⁴ CFU, n = 20 or 1 × 10⁵ CFU, n = 20) of E. coli. Chicks treated with CpG-ODN by the IPL route had significantly lower clinical signs and bacterial load compared to the group treated with saline ( P < 0.05). CpG-ODN-treated groups were significantly protected against E. coli septicemia. We observed dose- and exposure time-dependent immunoprotective effects of IPL CpG-ODN in chicks. We found that IPL delivery of CpG-ODN can induce protective immunity as early as 6 hr that remains effective at least until day 5 post-treatment. Moreover, there were no adverse effects of IPL delivery of CpG-ODN on growth or mortality up to 42 days of age. Based on these findings, it can be suggested that CpG-ODN delivery by IPL route can be a promising alternative to antibiotics for inducing protective immunity in chicks during the critical first week of neonatal life.

Effect of dietary niacin supplementation on performance, total tract nutrient retention, carcass yield and meat lipid profile of growing turkeys

A study was conducted to investigate the influence of dietary high or recommended nicotinic acid (niacin) supplementation on growth performance, total tract nutrient digestibility, hematology, serum chemistry, and lipoprotein concentrations in the serum and meat of growing turkeys. Turkeys were assigned to three treatments on weight equalisation basis with five replicates of eight turkeys in each group. Experimental diets were: no supplemental niacin (Control), a diet supplemented with 60 mg/kg niacin termed as recommended niacin supplementation and a diet supplemented with 180 mg/kg niacin termed as high niacin supplementation (HNS). The experiment lasted for the grower (Day 56–84) and finisher phases (Day 84–112) of the birds. Dietary inclusion of HNS increased (P &lt; 0.01) bodyweight gain, metabolisable energy (Days 84 and 112), dressing percentage and retail cut parts of turkeys (Day 112) in relation to the Control-fed turkeys. Furthermore, least white blood cell count and higher concentrations of packed cell volume, red blood cells and hemoglobin (P &lt; 0.01) were found in turkeys fed HNS on Days 84 and 112. Similarly, turkeys in the HNS group had improved serum constituents including serum protein, uric acid, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphate. The blood and meat lipid profile analysis showed that low density lipoprotein and total cholesterol were least (P &lt; 0.05) in turkeys fed HNS. Collectively, dietary high supplementation of niacin (180 mg/kg) improves production performances, reduces serum and meat fat content and improve indicators of stress resistance ability in growing turkeys.

Effect of Dietary Niacin Supplementation on Growth Performance, Nutrient Digestibility, Hematology, and Lipoprotein Concentrations of Young Turkeys, Meleagris gallopavo

The growth performance, nutrient digestibility, hematology, serum chemistry, and lipoprotein concentrations of turkey (Meleagris gallopavo) poults fed diets supplemented with high or recommended concentrations of niacin were investigated in this study. A total of 120 four-week-old turkey poults were randomly divided into three treatment groups with five replicates of eight birds in each group. The poult diets were supplemented with 0.0, 60, and 180 mg/kg niacin in the three treatments, termed control, recommended niacin supplementation (RNS), and high niacin supplementation (HNS), respectively. The study lasted for four weeks. The results showed that the HNS treatment reduced the feed intake and increased the body weight gain of poults. The apparent, nitrogen-corrected, and true metabolizable energy contents were the highest in the HNS-group turkey poults (P<0.05). The red and white blood cell counts and hemoglobin concentration of the turkeys improved with increasing niacin supplementation (P<0.01). The serum constituents, including the serum protein and globulin, were significantly increased (P<0.05), while the uric acid and creatinine contents were significantly reduced in the HNS-group turkeys. Similarly, the HNS-group turkeys exhibited significantly reduced alanine aminotransferase (ALT) and alkaline phosphatase (ALP) contents, while the RNS-group turkeys had the least aspartate aminotransferase (AST) content. In addition, the HNS-group turkeys had the least serum low-density lipoprotein (LDL), triglyceride, and total cholesterol concentrations and the highest serum high-density lipoprotein (HDL) (P<0.01) concentrations. In conclusion, the supplementation of 180 mg/kg niacin in the diet reduced the feed intake and serum ALT, ALP, LDL, triglyceride, and cholesterol contents and increased the body weight gain, metabolizable energy, and HDL concentration in turkeys. This study showed that niacin supplementation could reduce the fat content without compromising the body weight gain and increase stress resistance in turkey poults.

Effects of Management Related Practices on Turkey Hen Performance Supplemented With Either Original XPC™ or AviCare™

During commercial production, turkeys may be exposed to several different types of stressors related to environmental conditions and management practices. Historically, antibiotics have been used to aid in the alleviation of the impacts of stressful situations, and alternatives to antibiotics related to reducing stress are being researched. This study consisted of three rearing trials and had two objectives: (1) Investigate the effects of common U.S. turkey production practices, including environmental and management induced stress, on turkey hens grown to 63 days, and (2) Determine the response of stressed birds to dietary supplementation with fermentation derived functional metabolites. Treatments consisted of a positive control (stressed but not supplemented), a negative control (non-stressed and not supplemented) and two treatment groups that were stressed and supplemented with different products (Original XPC™ or AviCare™). Supplemental products were administered in a dry (feed) and liquid (drinking water) form, and consisted of fermentation derived functional metabolites. Products were evaluated on their effectiveness to mitigate stress responses and turkey performance. Birds were exposed to some combinations of the following stressors: feed and water withdrawal, cold, heat, and crowding. Although the stressors in this study were applied for less than 24 h, they produced significant physiological responses. Blood corticosterone levels, measured immediately after stress, were significantly higher in positive control birds than in negative control birds. In addition, stressed birds had reduced body weights and increased FCR after stress. Stressed birds, supplemented with products had mixed, but generally positive response as measured by bird performance. Based on the response to stress, as observed by alterations in blood corticosterone levels and differences in performance between the two control groups, researchers induced an effective stress model. The use of supplementary products consisting of fermentation derived functional metabolites shows promise for reducing negative impacts of a mixture of stressors.

Effects of meniran (Phyllanthus niruri L.) administration on leukocyte profile of broiler chickens infected with Mycoplasma gallisepticum

Aim

This study aimed to evaluate the effects of Meniran extract (Phyllanthus niruri L.) administration on leukocyte profile of broiler chickens infected with Mycoplasma gallisepticum.

Materials and Methods

Thirty broiler chickens, 21 days old were divided into five treatment groups. P0 (-): Chickens without any treatment; P0 (+), P1, P2, and P3: Chickens were infected with M. gallisepticum 10⁸ cells/ml/animal orally, then given no treatment, Meniran extract 60%, 62.5%, and 65% orally at a dose of 1 ml/kg body weight, respectively. The treatment of Meniran extract was given for 7 days.

Results

Leukocyte count with the lowest number showed in Group P0 (-) and Group P3 (p>0.05). Increased number of basophils was found in Group P0 (+), Group P1, and Group P2. The highest number of heterophils was found in Group P0 (+) and was significantly different from Group P0 to P3 (p<0.05). The same pattern was also seen in the number of lymphocytes in all treatment groups. The number of monocytes showed no significant difference between all treatment groups (p>0.05).

Discussion

Increased the number of leukocytes is often observed in inflammation due to general infections, trauma, or toxicity. Shifting in the number of heterophile or lymphocytes, an increase in the number of monocytes, basophils, and eosinophils may also be associated with various infectious or inflammatory conditions. Heterophils play a role as an antibacterial defense through several effective mechanisms. When infections and inflammation occur, the heterophils will increase to phagocytosis microbe.

Conclusion

It can be concluded that Meniran extract (P. niruri L.) at a dose of 65% can decrease the total number of leukocytes in broilers infected with M. gallisepticum.

Yeast β-d-glucans induced antimicrobial peptide expressions against Salmonella infection in broiler chickens

The present study was designed to investigate the effects of yeast β-d-glucans (YG) on gene expression of endogenous β-defensins (AvBDs), cathelicidins (Cath) and liver-expressed antimicrobial peptide-2 (LEAP-2) in broilers challenged with Salmonella enteritidis (SE). 240 day-old Cobb male broilers were randomly assigned to 2×2 factorial arrangements of treatments with two levels of dietary YG (0 or 200mg/kg in diet) and two levels of SE challenge (0 or 1×10(9) SE at 7-9 days of age). The results showed SE infection reduced growth performance,and increased salmonella cecal colonization and internal organs invasion, increased concentration of intestinal specific IgA and serum specific IgG antibody, as compared to uninfected birds. SE challenge differentially regulated AvBDs, Caths and LEAP-2 gene expression in the jejunum and spleen of broiler chickens during the infection period. However, YG supplementation inhibited the growth depression by SE challenge, and further increased level of serum specific IgG and intestinal specific IgA antibody. Higher level of salmonella colonization and internal organs invasion in the SE-infected birds were reduced by YG. SE-induced differentially expression patterns of AMPs genes was inhibited or changed by YG. Results indicated YG enhance chicken's resistance to salmonella infection.

Prebiotics and gut microbiota in chickens

Prebiotics are non-digestible feed ingredients that are metabolized by specific members of intestinal microbiota and provide health benefits for the host. Fermentable oligosaccharides are best known prebiotics that have received increasing attention in poultry production. They act through diverse mechanisms, such as providing nutrients, preventing pathogen adhesion to host cells, interacting with host immune systems and affecting gut morphological structure, all presumably through modulation of intestinal microbiota. Currently, fructooligosaccharides, inulin and mannanoligosaccharides have shown promising results while other prebiotic candidates such as xylooligosaccharides are still at an early development stage. Despite a growing body of evidence reporting health benefits of prebiotics in chickens, very limited studies have been conducted to directly link health improvements to prebiotic-dependent changes in the gut microbiota. This article visits the current knowledge of the chicken gastrointestinal microbiota and reviews most recent publications related to the roles played by prebiotics in modulation of the gut microbiota and immune functions. Progress in this field will help us better understand how the gut microbiota contributes to poultry health and productivity, and support the development of new prebiotic products as an alternative to in-feed antibiotics.

Effects of chromium and chromium + vitamin C combination on metabolic, oxidative, and fear responses of broilers transported under summer conditions

A total of 240 female broilers (42 days old) were randomly assigned to four groups with six replicates and fed either a basal diet (two control groups) or a basal diet supplemented with either 1,200 μg Cr(+3) from chromium (Cr) methionine/kg (Cr group) or 1,200 μg Cr(+3) from Cr methionine plus 800 mg vitamin C (Vit C)/kg of diet (Cr + Vit C group). After 7 days on the dietary treatment, all groups except one of the controls were transported for 3 h under the summer conditions. Performance parameters were not influenced by dietary treatments. The plasma concentrations of insulin, triiodothyronine, triglyceride, and the ratio of triiodothyronine/thyroxin were decreased and the ratio of glucose/insulin was increased due to transport process. Road transportation also increased the plasma concentrations of protein, cholesterol, aspartate aminotransferase, and creatine kinase and decreased the concentration of low-density lipoprotein cholesterol in the Cr + Vit C group. The pretransport concentrations of insulin and triiodothyronine were highest in the Cr + Vit C group. The concentration of phosphorous was lower in the Cr group than that in the other groups after transport. No significant effects of dietary treatments were observed on the other biochemical parameters. Transport increased malondialdehyde concentration in the control group and did not change plasma total antioxidant capacity and erythrocyte glutathione peroxidase activity. Either in combination or alone, Cr increased plasma total antioxidant capacity (before transport P ≤ 0.05, after transport P = 0.07) but did not affect the concentration of malondialdehyde and activity of glutathione peroxidase. The duration of tonic immobility (TI) was similar between nontransported control chicks and transported chicks without any supplements. Pretreatment with Cr + Vit C significantly reduced the duration of TI.

β-1,3/1,6-Glucan alleviated intestinal mucosal barrier impairment of broiler chickens challenged with Salmonella enterica serovar Typhimurium

This study investigated the protective effect of β-1,3/1,6-glucan on gut morphology, intestinal epithelial tight junctions, and bacterial translocation of broiler chickens challenged with Salmonella enterica serovar Typhimurium. Ninety Salmonella-free Arbor Acre male broiler chickens were randomly divided into 3 groups: negative control group (NC), Salmonella Typhimurium-infected positive group (PC), and the Salmonella Typhimurium-infected group with dietary 100 mg/kg of β-1,3/1,6-glucan supplementation (T) to determine the effect of β-1,3/1,6-glucan on intestinal barrier function. Salmonella Typhimurium challenge alone significantly decreased villus height (P < 0.001), villus height/crypt depth ratio (P < 0.05), and the number of goblet cells (P < 0.001) in the jejunum at 14 d postinfection (dpi), but significantly increased the number of intestinal secretory IgA (sIgA)-expressing cells at 14 dpi (P < 0.01) and total sIgA levels in the jejunum at 7 (P < 0.05) and 14 dpi (P < 0.01) compared with the unchallenged birds (NC). Dietary β-1,3/1,6-glucan supplementation not only significantly increased villus height, villus height/crypt depth ratio, and the number of goblet cells (P < 0.01), but also increased the number of sIgA-expressing cells (P < 0.05) and sIgA content in the jejunum at 14 dpi (P < 0.01) in birds challenged with Salmonella Typhimurium in comparison with Salmonella Typhimurium challenge alone. β-1,3/1,6-Glucan addition had significant inhibitory effects (P < 0.05) on cecal Salmonella colonization levels and liver Salmonella invasion of the Salmonella Typhimurium-infected birds compared with the PC group. Intestinal tight junction proteins claudin-1, claudin-4, and occludin mRNA expression in the jejunum at 14 dpi was significantly decreased by Salmonella Typhimurium challenge alone (P < 0.01) compared with that of the NC group, whereas β-1,3/1,6-glucan supplementation significantly increased claudin-1 and occludin mRNA expression (P < 0.01) at 14 dpi in the jejunum of the Salmonella Typhimurium-infected birds in comparison with the PC group. Our results indicate that dietary β-1,3/1,6-glucan can alleviate intestinal mucosal barrier impairment in broiler chickens challenged with Salmonella Typhimurium.

Comparison of hematologic and serologic profiles of broiler birds with normal and severe degrees of white striping in breast fillets

White striping is the white striation occasionally observed parallel to the direction of muscle fibers in broiler breast fillets and thighs at the processing plant. Broiler breast fillets can be categorized as normal (NORM), moderate (MOD), or severe (SEV) based on the degree of white striping. Histologically, SEV fillets are characterized by the highest degree of degeneration of muscle fibers along with fibrosis and lipidosis when compared with NORM. The present study was undertaken to compare the hematologic and serologic profiles of broilers with NORM and SEV degrees of white striping to get more information on the systemic changes associated with the condition. Day-old male broiler chicks of a commercial strain were grown on the same diet in 6 replicate pens (n = 32 birds/pen). Blood samples (5 mL) were collected from the wing vein of each bird on the day before processing for analyzing hematologic and serologic profiles. At 63 d, the birds were weighed and processed in a commercial inline processing system. Weight of the butterfly fillets, liver, and abdominal fat pad were recorded. Left-side fillets were scored to obtain the degree of white striping for each bird. Representative samples for NORM (n = 24) and SEV (n = 17) categories were selected to compare the hematologic and serologic profiles. The SEV birds had greater (P < 0.05) live, fillet, and liver weights, as well as fillet yield, compared with the NORM birds, but the abdominal fat yield was less (P < 0.05) in SEV birds. The NORM and SEV birds did not show any differences in various hematological parameters, including the differential leukocyte count. Conversely, SEV birds had elevated (P < 0.05) serum levels of creatine kinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase. These results suggest that there is no systemic infectious or inflammatory condition associated with a SEV degree of white striping. The elevated serum enzyme levels confirm the muscle damage associated with the degenerative myopathy in SEV birds.

Barley-derived β-glucans increases gut permeability, ex vivo epithelial cell binding to E. coli, and naive T-cell proportions in weanling pigs

Weaning in young animals is associated with an increased incidence of gastrointestinal infections. β-glucans exert numerous physiological effects, including altering immune function. The objective of this study was to determine the effects of feeding barley (Hordeum vulgare L.)-derived β-glucans on immune and intestinal function in weanling pigs (Sus scrofa). Thirty-one individually-housed Dutch Landrace pigs (21 d; initial BW, 6,298 ± 755 g) were weaned and fed a wheat-based diet (control) or a low (Lo-BG), medium (Med-BG), or high β-glucan-containing barley-based diet (Hi-BG) for 2 wk with 7 or 8 pigs/treatment. Intestinal segments were analyzed for permeability using Ussing chambers and K88 Escherichia coli adhesion to enterocytes was assessed ex vivo. Immune cells from mesenteric lymph nodes, peripheral blood, and Peyer's patches were analyzed for lymphocyte subsets by indirect immunofluorescence and the ability to respond ex vivo to mitogens by (3)H-thymidine incorporation. Hematology and neutrophil function were determined by flow cytometry. Neutrophil burst, size, and granularity, lymphocyte proliferation, and B-cell distribution in peripheral blood lymphocytes, Peyer's patches, and mesenteric lymph nodes were not affected by β-glucans content of the diet. The β-glucans content of the diet altered blood concentrations of erythrocytes and leukocytes, CD4, CD45RA, and CD8 blood cells (P < 0.05). In addition, feeding β-glucan resulted in increased (P < 0.05) percentage CD45RA positive cells in peripheral blood lymphocytes, Peyer's patches, and mesenteric lymph nodes. Mannitol permeability and tissue conductance were increased (P < 0.05) in Hi-BG fed pigs compared with control pigs. Percentage maximum K88-E.coli binding was increased in proportion to the β-glucan content of the diet (P < 0.05). Although β-glucan feeding during the weaning period increased blood lymphocytes and the proportion of naïve T-cells, it also increased E. coli-enterocyte binding and intestinal permeability. β-glucan may alter immune and intestinal function of weaning pigs.

Effects of Saccharomyces cerevisiae extract on haematological parameters, immune function and the antioxidant defence system in breeder hens fed aflatoxin contaminated diets

The study was conducted to investigate the efficacy of Saccharomyces cerevisiae extract (SC) on haematological parameters, immune function, and the antioxidant defence system in breeder hens fed a diet contaminated with low level aflatoxin (AF). Forty-eight Ross 308 breeder hens were fed on diets containing AF (0 or 100 µg/kg) and SC (0 or 1 g/kg) in a 2 × 2 factorial arrangement. Red blood cell (RBC), white blood cell (WBC), and platelet counts, differential leucocyte counts, blood CD3+, CD4+, CD8+ and CD5+ T cell ratios, phagocytic activity and oxidative burst of heterophils, plasma and liver catalase activity, and malondialdehyde (MDA) and ascorbic acid concentrations were measured. 3. Plasma and liver MDA concentrations increased (P < 0·05), liver catalase activity decreased (P < 0·05) and total WBC count tended to decrease (P = 0·082) in hens fed the contaminated diet. WBC count, monocyte percentage, phagocytic activity and oxidative burst of heterophils increased (P < 0·05), and plasma MDA concentration tended to decrease (P = 0.088) in SC extract supplemented hens. There was a significant interaction between AF and SC on heterophil, lymphocyte, CD5+ cell percentages, and plasma catalase activity. Blood heterophil percentage decreased but lymphocyte percentage increased in hens fed on the AF contaminated diet without SC supplementation. SC supplementation counteracted the negative effect of AF on heterophils and lymphocytes. The CD5+ cell percentage decreased in unsupplemented hens fed the AF contaminated diet and this negative effect was minimised in SC supplemented hens. Plasma catalase activity increased in SC supplemented hens fed the uncontaminated diet whereas the effect of SC decreased in hens fed the AF contaminated diet. 4. The SC reduced some of the some adverse effects of AF, and improved functions of the non-specific immune system. Therefore, the SC extract which has been used for improving productive performance in birds and mammals may also be useful for modulating some of the effects of a low level, chronic dosage of AF.

Effects of dietary yeast extract on turkey stress response and heterophil oxidative burst activity

1. Effective nutritional approaches to counteract the negative effects of stress may provide food animal producers with useful alternatives to antibiotics. In this study, turkeys were fed on a standard diet, or the same diet supplemented with yeast extract (YE), to determine if YE would improve disease resistance in a stress model. 2. At 16 weeks of age, half of the birds were exposed to a bacterial challenge using a coarse spray of the pen environment. A subset of control and challenged birds was also treated with dexamethasone (Dex) prior to challenge (Dex/challenge). At 18 weeks, another subset was subjected to a 12?h transport stress protocol (Challenge/transport). All birds were bled and necropsied the morning after transport. The numbers and proportions of blood cells and the heterophil oxidative burst activity (OBA) were determined. Serum corticosterone (Cort) levels of male birds were measured using a commercial ELISA kit. Body weight and gain were increased by YE during week 1. 3. YE decreased mortality and bacterial isolation following Dex/challenge only in females. Cort levels in male turkeys were decreased by YE and Dex treatment. OBA was higher in males and in birds given YE and was reduced by challenge and transport. 4. These results suggest there may be gender differences in the turkey stress response and that dietary YE has potential for modulating the impact of stress on innate immunity of turkeys.

Immune responses to dietary beta-glucan in broiler chicks during an Eimeria challenge

Escalating consumer concerns regarding pathogen resistance have placed the poultry industry under mounting pressure to eliminate the use of chemotherapeutic agents as feed additives. One possible alternative receiving increased attention is the use of immunomodulators such as β-glucan. A study was conducted to investigate the effects of a yeast-derived β-glucan (Auxoferm YGT) on broiler chick performance, lesion scores, and immune-related gene expression during a mixed Eimeria infection. Day-old chicks were fed diets containing 0, 0.02, or 0.1% YGT. On d 8 posthatch, one-half of the replicate pens were challenged with a mixed inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Measurements were taken and samples collected on d 4, 10, 14, and 21 posthatch. Dietary supplementation had no effect on performance or mortality. On d 14, 3 birds per pen (n = 24/treatment) were scored for intestinal coccidia lesions. Gross lesion severity was significantly reduced in birds supplemented with 0.1% YGT. On d 10, inducible nitric oxide synthase (iNOS) expression was downregulated in the jejunum of challenged birds fed 0.1% YGT. Expression of iNOS in the ileum was downregulated in the nonchallenged birds, but upregulated in the challenged birds fed 0.1% YGT on d 14. Interleukin (IL)-18 was upregulated in the jejunum of 0.1% YGT-treated birds. Interferon (IFN)-γ expression was decreased in challenged and nonchallenged birds fed 0.1% YGT. The IL-4 expression was downregulated in the nonchallenged birds with 0.1% YGT diet supplementation. The IL-13 and mucin-1 levels were also reduced due to β-glucan supplementation. Mucin-2 expression was increased in the nonchallenged birds, but decreased in the infected birds fed 0.1% YGT. These results suggest that although Auxoferm YGT at doses of 0.02 and 0.1% does not influence performance, it significantly reduces lesion severity and is capable of altering immune-related gene expression profiles, favoring an enhanced T helper type-1 cell response during coccidiosis.