Effects of in ovo injection with selenium on immune and antioxidant responses during experimental necrotic enteritis in broiler chickens

Selenium nanoparticles promotes intestinal development in broilers by inhibiting intestinal inflammation and NLRP3 signaling pathway compared with other selenium sources

This study aimed to investigate how various selenium sources affect the intestinal health of broiler chickens. A total of 384, one-day-old Arbor Acres broilers were weighed and randomly allocated to four treatment groups. The control diet was a basal diet added with: 0.2 mg/kg Sodium Selenite (SS-control), 0.2 mg/kg Selenium nano-particles (Nano-Se), 0.2 mg/kg Selenomethionine (SeMet), and 0.2 mg/kg Selenocysteine (Sec) as the treatments. The results indicated that Nano-Se and SeMet were effective in enhancing the villus height (VH) and the villus height/crypt depth ratio (VH/CD) in the jejunum compared to (SS) (P < 0.05). The inclusion of Nano-Se into the diets increased the mRNA levels of zonula occluden-1 (ZO-1), ZO-2, Occludin, Claudin-1, and Claudin-3 compared to the SS diet (P < 0.05). The SeMet increased the levels of ZO-1 and Claudin-3 compared to the SS (P < 0.05). Moreover, SeMet upregulated the marker genes of intestinal enteroendocrine cells, stem cells, and epithelial cells compared to the SS diet (P < 0.05). However, supplementation of Nano-Se reduced the mRNA levels of interleukin 1β (IL-1β), and IL-8 and the concentration of reactive oxygen species (ROS) in the jejunum compared to the SS (P < 0.05). The Nano-Se and SeMet also increased the protein levels of CAT and SOD compared to the SS and Sec diet (P < 0.05). The number of the goblet cells and Mucin-2 (Muc2) levels were the highest in the Nano-Se group (P < 0.05). The protein expression levels of goblet cell differentiation regulator (v-myc avian myelocytomatosis viral oncogene homolog, c-Myc) were highest in the Nano-Se compared to the SS diet (P < 0.05). The Nano-Se decreased the mRNA and protein levels of NLRP3 signaling pathway-related genes compared to the SS diet (P < 0.05). In conclusion, our study demonstrated that Nano-Se and SeMet are better at improving the intestinal health of 21-day-old broilers. Additionally, Nano-Se demonstrated superior antioxidant and anti-inflammatory effects, promoting the development of intestinal goblet cells by modifying the NLRP3 signaling pathway.

Supplementation with organic yeast-derived selenium provides immune protection against experimental necrotic enteritis in broiler chickens

Necrotic enteritis (NE) is a potentially fatal poultry disease that causes enormous economic losses in the poultry industry worldwide. The study aimed to evaluate the effects of dietary organic yeast-derived selenium (Se) on immune protection against experimental necrotic enteritis (NE) in commercial broilers. Chickens were fed basal diets supplemented with different Se levels (0.25, 0.50, and 1.00 Se mg/kg). To induce NE, Clostridium perfringens (C. perfringens) was orally administered at 14 days of age post hatch. The results showed that birds fed 0.25 Se mg/kg exhibited significantly increased body weight gain compared with the non-supplemented/infected birds. There were no significant differences in gut lesions between the Se-supplemented groups and the non-supplemented group. The antibody levels against α-toxin and NetB toxin increased with the increase between 0.25 Se mg/kg and 0.50 Se mg/kg. In the jejunal scrapings and spleen, the Se-supplementation groups up-regulated the transcripts for pro-inflammatory cytokines IL-1β, IL-6, IL-8, iNOS, and LITAF and avian β-defensin 6, 8, and 13 (AvBD6, 8 and 13). In conclusion, supplementation with organic yeast-derived Se alleviates the negative consequences and provides beneficial protection against experimental NE.

Effects of in ovo injection of organic selenium on the hatchability of broiler breeder hen eggs and resulting chick physiology and performance

BACKGROUND

Selenium is an essential mineral for poultry. The conflicting reports about its in ovo injection are the justification for the more detailed investigation.

OBJECTIVES

The aim of this study was to investigate the effects of in ovo injection of organic selenium on the hatching traits of broiler chickens and their performance.

METHODS

Three hundred and twenty eggs of Ross 308 strain with an average weight of 65 g and 160 chicks were randomly divided into 4 treatment groups (each with 8 replicates of 10 eggs each for hatching parameters and 4 replicates of 10 chicks for broiler farming parameters): negative control (no injection), positive control (in ovo injection of 0.272 mL of normal saline solution) and 2 selenium treatments (in ovo injection of 2.72 or 5.44 μg of organic selenium). Injection was into the amniotic sac on the 10th day of incubation. Effects of in ovo injection on hatching and performance traits, blood parameters, immune responses, carcass characteristics, meat fatty acid profile, cecal microbial population and selenium consternation in the tibia were measured.

RESULTS

Fewer chicks from the injected treatments hatched than from the negative control group (p < 0.01). However, the injection of selenium increased feed intake and the final weight of the birds (p < 0.01). Blood parameters were also affected. Glucose and cholesterol in experimental treatment chicks was lower than those of the controls (p < 0.01), whereas blood lipoproteins (VLDL, LDL and HDL) and the ratio of cholesterol to HDL was significantly increased in the treatments injected with selenium (p < 0.01). There was no significant difference in the immune response or microbial population between the experimental groups, but carcass components, such as thigh, breast, wing and abdominal fat weight, were significantly greater in the selenium treatments.

CONCLUSIONS

Intra-egg injection of organic selenium produced favourable effects on performance of broiler chickens, although it had no effect on immune response or microbial population. However, the negative effect on hatching of chickens needs to be prevented to result in an acceptable economic return for the producer.

In ovo feeding of l-arginine and selenium nanoparticles influences post-hatch growth, muscle development, antioxidant status, and meat quality in slow-growing chickens

This study investigated the effects of in ovo feeding (IOF) of l-arginine (L-Arg), selenium nanoparticles (SeNP), and a combination of L-Arg and SeNP on the hatchability, post-hatch growth, muscle development, antioxidant status, and meat quality of slow-growing chickens. On day 18 of incubation, a total of 960 fertilized eggs with similar weights were randomly assigned to 4 treatment groups with 4 replicates of 60 eggs each: (1) non-injected control group (Control), (2) injected with 1% of L-Arg (IOF_L-Arg), (3) injected with 0.3 µg/egg of SeNP (IOF_SeNP), and (4), injected with 1% of L-Arg and 0.3 µg/egg of SeNP (IOF_L-Arg + SeNP). A completely randomized design was used. After hatching, 640 mixed-sex chicks were allocated to 4 treatment groups and split into 4 replicate pens (40 birds per pen). All groups of chicks were fed with commercial feed ad libitum until they reached 63 d of age and were subsequently weighed and slaughtered. The results of the present study showed that hatchability was similar among treatments. Final BW or breast muscle yield was not affected (P > 0.05) by IOF treatment. Chickens treated with IOF_L-Arg + SeNP exhibited decreased feed conversion ratio, drip loss, and increased protein content in breast meat (P < 0.05). The IOF_L-Arg + SeNP group exhibited a higher density of breast muscle fibers than the control group (P < 0.05). Overall, in ovo feeding of L-Arg combined with SeNP resulted in improved feed efficiency and enhanced antioxidant capacity at hatch without any adverse effects on chicken hatchability, health, or subsequent growth. Furthermore, meat from chickens in the IOF_L-Arg + SeNP group exhibited a preferable texture with a higher protein content.

The Effects of In Ovo Feeding of Selenized Glucose on Selenium Concentration and Antioxidant Capacity of Breast Muscle in Neonatal Broilers

This study aims to investigate the impacts of in ovo feeding (IOF) of selenized glucose (SeGlu) on selenium (Se) level and antioxidant capacity of breast muscle in newborn broilers. After candling on 16 day of incubation, a total of 450 eggs were randomly divided into three treatments. On the 17.5th day of incubation, eggs in a control treatment were injected with 0.1 mL of physiological saline (0.75%), while the 2nd group and 3rd group were supplied with 0.1 mL of physiological saline containing 10 μg Se from SeGlu (SeGlu10 group) and 20 μg Se from SeGlu (SeGlu20 group). The results showed that in ovo injection in both SeGlu10 and SeGlu20 increased the Se level and reduced glutathione concentration (GSH) in pectoral muscle of hatchlings (P < 0.05). Compared with the control group, the SeGlu20-treated chicks significantly enhanced the activity of the superoxide dismutase (SOD) and mRNA expression of NAD(P)H quinone dehydrogenase 1 (NQO1) in breast muscle, while there was upregulation in mRNA expressions of glutathione peroxidase 1 (GPX-1) and thioredoxin reductase 1 (TrxR1) and higher total antioxidant capacity (T-AOC) in SeGlu10 treatment (P < 0.05). However, no significant difference on enzyme activities of glutathione peroxidase (GR), glutathione reductase, thioredoxin reductase, concentration of malondialdehyde, and free radical scavenging ability (FRSA) of superoxide radical (O2-•) and hydroxyl radical (OH•) was observed among the three treatments (P > 0.05). Therefore, IOF of SeGlu enhanced Se deposition in breast muscle of neonatal broilers. In addition, in ovo injection of SeGlu could increase the antioxidant capacity of newborn chicks possibly through upregulating the mRNA expression of GPX1, TrxR1, and NQO1, as well as the SOD activity.

Effect of In Ovo Administration of a Multi-Strain Probiotic and Zinc Glycine Chelate on Antioxidant Capacity and Selected Immune Parameters in Newly Hatched Chicks

The aim of this study was to determine the effect of in ovo co-supplementation of chicken embryos with a multi-strain probiotic containing effective microorganisms and zinc glycine chelate on total antioxidant capacity; concentrations of sulfhydryl groups, bityrosine bridges, formylkynurenines, hydroperoxides, proteins, corticosterone, pro- and anti-inflammatory cytokines and heat shock proteins; and the activity of catalase and superoxide dismutase in the serum, yolk sac and tissues of broiler chickens at 12 h and at 7 days after hatching. The results indicate high SOD activity in the small and large intestines of chicks at 12 h post-hatch in the groups receiving the multi-strain probiotic and in the small intestine and yolk sac of birds receiving the multi-strain probiotic and Zn-Gly chelate. High concentrations of TNF-α and IFN-γ in the yolk sac and serum after in ovo administration of Zn-Gly chelate were observed 12 h after hatching. The use of a probiotic and a probiotic with Zn-Gly chelate increased the total antioxidant capacity in the tissues of chickens. It can be concluded that in ovo administration of a multi-strain probiotic and Zn-Gly chelate can maintain the oxidant/antioxidant balance in chickens and increase the defense capacity against oxidative stress.

The influence of bacterial selenium nanoparticles biosynthesized by Bacillus subtilus DA20 on blood constituents, growth performance, carcass traits, and gut microbiota of broiler chickens

Selenium is one of the necessary micronutrients needed for enhanced gut microbiota and oxidative stress of poultry, so it improves their performance. In this study, Bacillus subtilus DA20 isolate that identified at the gene level by PCR was employed to produce eco-friendly selenium nanoparticles (BSeNPs) and investigate their effects on growth performance, carcass characteristics, blood parameters, and gut microbiota of Indian River (IR) broiler chickens. The obtained selenium nanoparticles were spherical with size of 56 nm and net negative charge of -22.36 mV; the BSeNPs were surrounded with active compounds, which besides the tiny size attributed to antioxidant and antibacterial activity. Forty hundred and eighty unsexed IR broilers, 1-day old, were reared for 35 d. The chicks were weighed separately and distributed into 3 treatment groups; each group contained 4 replicates (40 birds per replicate). Chicks in the first, second, third, fourth groups were fed control diets supplemented with 0, 20, 40, and 60 µg/kg of BSeNPs, respectively; but the fifth group was fed 300 µg/kg bulk selenium. Dietary supplementation with BSeNPs (40 µg/kg diet) significantly increased the body weight of chicks and decreased the feed conversion ratio. Additionally, dietary BSeNPs significantly (P = 0.046) lowered the fat content in broiler by 24% compared to the control; on the other hand, the breast muscle significantly increased (P = 0.035) by 19%. The content of total bacterial count (TBC), total yeast mold count (TYMC), E. coli, and Salmonella counts significantly was decreased with BSeNPs and Se compared to the control. However, lactic acid bacteria (LAB) was significantly increased with BSeNPs (60 μg/kg) when compared to control, showing the beneficial effects of BSeNPs in reducing pathogens and enhancing the beneficial bacteria, which reflects on the broiler performance.

Effect of Dietary Organic Selenium on Growth Performance, Gut Health, and Coccidiosis Response in Broiler Chickens

A total of 252 one-day-old Ross broilers were randomly allocated to one of six treatments in a 2 × 3 factorial arrangement with respective Eimeria challenges (non-infection and infection) and three different selenium (Se) diets. Dietary treatments were as follows: (1) Se un-supplemented control (CON), (2) inorganic Se treatment (SS; 0.3 mg/kg as sodium selenite), and (3) organic Se treatment (SY; 0.3 mg/kg as selenized yeast). Six replicate cages were allocated per treatment. Chickens in the respective Eimeria infection groups were infected with an E. acervulina, E. tenella, and E. maxima oocyst mixture (15,000 oocysts/chicken) on day 16. Growth performance was measured on days 16, 22, and 24. On day 22, intestinal samples were collected from randomly selected chickens to evaluate gut lesion scores, antioxidant enzymes, and tight junction gene expression. Blood, breast, and liver samples were collected to analyze the Se concentrations on day 24. Dietary SY supplementation improved (p < 0.05) the growth performance of the chickens regardless of the Eimeria challenge. Moreover, independent of Eimeria infection, Se supplementation elevated (p < 0.05) the heme oxygenase 1 (HMOX-1) expression in jejunal mucosa at 6 days post-infection (dpi). Duodenal junctional adhesion molecule 2 (JAM-2) expression and jejunal occludin (OCLN) were elevated (p < 0.05) with dietary SY supplementation at 6 dpi. Among Se sources, broiler chickens fed with the SY diet showed higher (p < 0.05) Se concentrations in breast muscle and serum on 8 dpi. These results confirmed the beneficial effects of dietary Se and the efficiency of organic Se compared with inorganic Se for growth improvement and muscle Se enrichment in broiler chickens regardless of coccidiosis infection.

Physiological effects of in ovo delivery of bioactive substances in broiler chickens

The poultry industry has improved genetics, nutrition, and management practices, resulting in fast-growing chickens; however, disturbances during embryonic development may affect the entire production cycle and cause irreversible losses to broiler chicken producers. The most crucial time in the chicks' development appears to be the perinatal period, which encompasses the last few days of pre-hatch and the first few days of post-hatch. During this critical period, intestinal development occurs rapidly, and the chicks undergo a metabolic and physiological shift from the utilization of egg nutrients to exogenous feed. However, the nutrient reserve of the egg yolk may not be enough to sustain the late stage of embryonic development and provide energy for the hatching process. In addition, modern hatchery practices cause a delay in access to feed immediately post-hatch, and this can potentially affect the intestinal microbiome, health, development, and growth of the chickens. Development of the in ovo technology allowing for the delivery of bioactive substances into chicken embryos during their development represents a way to accommodate the perinatal period, late embryo development, and post-hatch growth. Many bioactive substances have been delivered through the in ovo technology, including carbohydrates, amino acids, hormones, prebiotics, probiotics and synbiotics, antibodies, immunostimulants, minerals, and microorganisms with a variety of physiological effects. In this review, we focused on the physiological effects of the in ovo delivery of these substances, including their effects on embryo development, gastrointestinal tract function and health, nutrient digestion, immune system development and function, bone development, overall growth performance, muscle development and meat quality, gastrointestinal tract microbiota development, heat stress response, pathogens exclusion, and birds metabolism, as well as transcriptome and proteome. We believe that this method is widely underestimated and underused by the poultry industry.

Selenium Nanoparticles Improved Intestinal Health Through Modulation of the NLRP3 Signaling Pathway

Selenium nanoparticles (SeNPs) play important roles in promoting animal health, however, their impact on intestinal health remains elusive. This study was intended to evaluate the effects of different doses of SeNPs on the intestinal health, especially the development of goblet cells in the broiler jejunum. A total of 480 1-day-old Arbor Acres broilers were randomly allotted to 5 treatments with 6 replications of 16 chicks each. Birds were fed with low selenium corn-soybean meal-based diets supplemented with 0.1, 0.2, 0.3, or 0.4 mg/kg of SeNPs. On d 21, dietary supplementation of SeNPs effectively reduced the mortality of broilers. The villus height and the villus height/crypt depth ratio of the jejunum showed significant quadratic effects with the increasing concentration of SeNPs (P < 0.05). The mRNA expression of zonula occluden-1 (ZO-1), ZO-2, claudin-3, and claudin-5 in the jejunum decreased linearly with the increasing dose of SeNPs (P < 0.05). The mRNA expression levels of interleukin 1 beta (IL-1β), IL-18, and the concentration of reactive oxygen species (ROS) in the jejunum decreased linearly with the increase of SeNPs concentration (P < 0.05). Compared with the control group, the number of goblet cells in the jejunum was significantly increased by adding 0.1 and 0.4 mg/kg SeNPs(P < 0.05). In addition, the mRNA expression of Mucin2 (Muc2) showed a significant quadratic relationship that increased after adding 0.1 mg/kg SeNPs (P < 0.05). Dietary SeNPs also linearly reduced the expression of v-myc avian myelocytomatosis viral oncogene homolog (c-myc) (P < 0.05). The mean density of TUNEL positive cells in the 0.2 and 0.4 mg/kg SeNPs groups were lower than the control group (P < 0.05). Similarly, the mRNA expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), NLR family pyrin domain containing 3 (NLRP3), cysteinyl aspartate specific proteinase-1 (Caspase-1), toll-like receptor-2 (TLR-2), and myeloid differentiation factor 88 (MyD88) in the jejunum decreased linearly with the increase of SeNPs concentration (P < 0.05). Results show that supplementation with 0.2 mg/kg SeNPs may decrease intestinal oxidative stress and inflammation by modifying the activation of NLRP3 signaling pathway, which can effectively promote intestinal goblet cells of 21-day-old broilers.

Comparing the Influences of Selenium Nanospheres, Sodium Selenite, and Biological Selenium on the Growth Performance, Blood Biochemistry, and Antioxidative Capacity of Growing Turkey Pullets

Supplementation of selenium in poultry feed is required in an optimum dose and form for optimizing the growth performance and health status. Selenium nanospheres are suggested as an efficient and alternative to the conventional organic or inorganic forms. The study evaluated the effects of selenium (Se) nanospheres (SeNPs) as an alternative to organic Se (Sel-Plex^®) or inorganic Se (sodium selenite, Se(IV Se(IV)) on the growth performance, carcass traits, blood biochemistry, and antioxidative capacity in turkey pullets. A total of 160 1-day-old Bronze turkey poults chicks were divided into four groups with 40 pullets each. The birds were fed on four types of diets as fellow: control (basal diet, 0.01 Se mg/kg), SeNPs (0.43 Se mg/kg), organic Se Sel-Plex^® (0.41 Se mg/kg), and inorganic Se(IV) (0.42 Se mg/kg) for 8 weeks. No changes were seen in the body weight gain in growing turkey pullet, but chicks fed with Sel-Plex^® form recorded the lowest feed intake (p < 0.05) compared to other treatments. Dietary SeNPs and Se(IV) selenium sources improved the feed conversion ratio compared to other treatments. All Se forms fed on turkey pullets showed higher carcass percentage weight and liver Se content than the control group. However, the gizzard percentage weight in the SeNPs group was lower than in the other treatments (p < 0.05). Birds fed SeNPs, and Sel-Plex^® forms supplemental diets had a lower cholesterol concentration (p < 0.05) than the control and Se(IV). While high-density lipoprotein (HDL) concentration was increased in SeNPs and Se(IV) groups, and total protein concentration was higher in the Se(IV) group. Furthermore, dietary SeNPs reduced (p < 0.05) the low-density lipoprotein (LDL), total lipids, triglycerides, alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine, uric acid, urea, and malondialdehyde plasma concentrations and increased the glutathione peroxidase activity (GPx) and total antioxidative capacity (TAC). In conclusion, the results confirmed that feeding turkey pullets on SeNPs form with the 0.4 Se mg/kg of feed enhanced feed efficiency, growth performance, carcass traits, plasma lipids concentration, and antioxidative capacity.

The health benefits of selenium in food animals: a review

Selenium is an essential trace mineral important for the maintenance of homeostasis in animals and humans. It evinces a strong antioxidant, anti-inflammatory and potential antimicrobial capacity. Selenium biological function is primarily achieved by its presence in selenoproteins as a form of selenocysteine. Selenium deficiency may result in an array of health disorders, affecting many organs and systems; to prevent this, dietary supplementation, mainly in the forms of organic (i.e., selenomethionine and selenocysteine) inorganic (i.e., selenate and selenite) sources is used. In pigs as well as other food animals, dietary selenium supplementation has been used for improving growth performance, immune function, and meat quality. A substantial body of knowledge demonstrates that dietary selenium supplementation is positively associated with overall animal health especially due to its immunomodulatory activity and protection from oxidative damage. Selenium also possesses potential antiviral activity and this is achieved by protecting immune cells against oxidative damage and decreasing viral replication. In this review we endeavor to combine established and novel knowledge on the beneficial effects of dietary selenium supplementation, its antioxidant and immunomodulatory actions, and the putative antimicrobial effect thereof. Furthermore, our review demonstrates the gaps in knowledge pertaining to the use of selenium as an antiviral, underscoring the need for further in vivo and in vitro studies, particularly in pigs.

The Role of Nutraceuticals and Phytonutrients in Chickens’ Gastrointestinal Diseases

Simple Summary

The use of nutraceuticals and phytonutrients in poultry nutrition has been extensively explored over the past decade. The interest in these substances is linked to the search for natural compounds that can be effectively used to prevent and treat some of the main diseases of the chicken. The serious problem of antibiotic resistance and the consequent legislative constraints on their use required the search for alternatives. The purpose of this review is to describe the current status of the effects of some substances, such as probiotics and prebiotics, organic acids, vitamins and phytogenic feed additives, focusing specifically on studies concerning the prevention and treatment of four main gastrointestinal diseases in chicken: salmonellosis, necrotic enteritis (caused by Clostridium perfringens), campylobacteriosis, and coccidiosis. A brief description of these diseases and the effects of the main bioactive principles of the nutraceutical or phytonutrient groups will be provided. Although there are conflicting results, some works show very promising effects, with a reduction in the bacterial or protozoan load following treatment. Further studies are needed to verify the real effectiveness of these compounds and make them applicable in the field.

Abstract

In poultry, severe gastrointestinal diseases are caused by bacteria and coccidia, with important economic losses in the poultry industry and requirement of treatments which, for years, were based on the use of antibiotics and chemotherapies. Furthermore, Salmonella spp., Clostridium perfringens, and Campylobacter jejuni can cause serious foodborne diseases in people, resulting from consumption of poultry meat, eggs, and derived products. With the spread of antibiotic resistance, which affects both animals and humans, the restriction of antibiotic use in livestock production and the identification of a list of “critically important antimicrobials” became necessary. For this reason, researchers focused on natural compounds and effective alternatives to prevent gastrointestinal disease in poultry. This review summarizes the results of several studies published in the last decade, describing the use of different nutraceutical or phytonutrients in poultry industry. The results of the use of these products are not always encouraging. While some of the alternatives have proven to be very promising, further studies will be needed to verify the efficacy and practical applicability of other compounds.

The effect of different types of in ovo selenium injection on the immunity, villi surface area, and growth performance of local chickens

Background and Aim

The presence of free radicals may lower chicken's performance. Thus, the antioxidant defense is needed and can be made through a nutritional approach such as selenium supplementation before hatches. This study aimed to investigate the type of selenium that, as an in ovo feeding (IOF) material, can provide the most enhancement of immunity, villi surface area, and early growth performance of local chickens.

Materials and Methods

This study, with a completely randomized design, used 480 fertile Kampung Unggul Balitbangtan (KUB, a selected local breed) chicken eggs, with 120 eggs per treatment for four treatments. The four treatments of IOF material included the treatment with organic selenium yeast (SY), organic hydroxy-selenomethionine (HSM), inorganic sodium selenite (SS), and uninjected selenium (control). A solution containing 0.15 ppm of different selenium was injected into the egg amnion after 18 days of incubation. Once hatched, the chicks were placed in three individual cages for each treatment (capacity of eight birds per cage). The parameters observed were the villi surface area, antibody titer, the number of total and differentiated leucocytes, glutathione peroxidase (GSH-Px) activity levels, and growth and feed efficiency of the early growth performance.

Results

All the in ovo selenium feeding, except SS, significantly affected the villi surface area, antibody titer, and lymphocyte and heterophil percentages; however, the feedings were still not optimal for enhancing antibody titers and total and differentiated leukocytes. All types of selenium were demonstrated to increase the activity of GSH-Px significantly compared to the control treatment (p<0.05). Furthermore, the daily gain and feed conversion ratio of the groups treated with SY and HSM was significantly improved compared to that of the control group.

Conclusion

In ovo SY and HSM improve immunity significantly, villi surface areas and performance. Therefore, both types are the best nutrient ingredients of IOF for building immunity and producing good performance in chickens.

Relative bioavailability of selenium yeast for broilers fed a conventional corn-soybean meal diet

The present study was conducted to assess the relative bioavailability of selenium (Se) as Se yeast (SY) relative to sodium selenite (SS) for broilers fed a conventional corn-soybean meal diet. A total of 360 one-d-old Arbor Acres commercial broilers were randomly assigned to 5 treatments with 6 replicates per treatment in a completely randomized design involving a 2 (Se sources: SY and SS) × 2 (added Se levels: 0.20 and 0.40 mg Se/kg) factorial design of treatments plus 1 (a Se-unsupplemented control diet) for 42 days. The results showed that Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney of broilers on d 21 and 42, glutathione peroxidase (GSH-Px) activity in the pancreas on d 21 as well as in the breast muscle and pancreas on d 42, and GSH-Px mRNA levels in the liver, heart, breast muscle and pancreas on d 21 increased linearly (p < .03) as levels of added Se increased. Furthermore, a difference (p ≤ .05) between SY and SS was detected for Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney, GSH-Px activity in pancreas on both d 21 and 42, as well as pancreatic GSH-Px mRNA level on d 21. Based on slope ratios from the multiple linear regressions of the above indices, the Se bioavailabilities of SY relative to SS (100%) were 111%-394% (p ≤ .05) when calculated from the Se concentrations in plasma, liver, heart, breast muscle, pancreas, kidney and GSH-Px activities in pancreas on d 21 and 42, as well as GSH-Px mRNA level in pancreas on d 21. The results from this study indicated that the Se from SY was more available for enhancing the Se concentrations in plasma or tissues and the expression and activity of GSH-Px in pancreas of broilers than the Se from SS.

Supplemental dietary selenium enhances immune responses conferred by a vaccine against low pathogenicity avian influenza virus

Selenium is a trace mineral that has antioxidant activities and can influence the immune system. However, antiviral effects of selenium have not been well studies in chickens. Chickens were therefore fed diets supplemented with two levels of two different sources of selenium (organic: selenium enriched yeast; SEY or inorganic: sodium selenite; SS). Chickens in the control groups did not receive supplemental dietary selenium. At 14 and 21 days of age, chickens were vaccinated with an inactivated low pathogenicity avian influenza virus (AIV, subtype H9N2) vaccine and blood samples were collected to determine the level of antibodies using hemagglutination inhibition (HI) and ELISA. At 30 days of age, chickens were also challenged with the same virus and swab samples were collected to assess the amount of virus shedding. Antibody levels, as measured by HI, increased significantly in the chickens that received higher levels of SEY at 16 days post vaccination. ELISA titers for IgM and IgY were higher in selenium supplemented chickens. Comparing to challenged control, virus shedding was lower in organic as well as inorganic selenium treated groups. Therefore, it may be concluded that supplemental dietary selenium could enhance vaccine conferred immunity thereby impacting protection against viral challenge in chickens.

In ovo injection of nano-selenium spheres mitigates the hatchability, histopathology image and immune response of hatched chicks

In ovo injection of nano-selenium (Se) produced by lactic acid bacteria (LAB-nano-Se) was investigated on the hatchability, immune responses and the histopathological alterations in hatched chicks. The eggs (18 day age) were injected with 0.5 ml of 0.9% NaCl (normal saline, NS), while the control group was kept without injection. In the third, fourth and fifth groups, the eggs were injected with 0.5 ml of NS and LAB-nano-Se at 10, 20 and 30 μg/egg. The results revealed improved growth performance in groups injected with LAB-nano-Se when compared to the control treatment. The highest final weight and weight gain were noticed in 20 μg LAB-nano-Se/egg group (p < .05). The feed conversion ratio was reduced in all treated groups when compared to the control group (p < .05). Groups injected with LAB-nano-Se showed enhanced hatchability of the whole incubated eggs (p < .05). Total lipids and cholesterol levels were decreased significantly in groups treated with LAB-nano-Se at 10 and 20 μg/egg when compared to the non-treated group. At the same time, globulin was increased by LAB-nano-Se in ovo injection. Furthermore, the total antioxidant capacity, catalase, glutathione peroxidase, superoxide dismutase increased in groups treated with LAB-nano-Se at 10 and 20 μg/egg with insignificant (p > .05) differences with those treated with LAB-nano-Se at 30 μg/egg using in ovo injection technique. Also, higher total blood protein and phagocytosis were significantly observed in groups treated with at 10, 20 and 30 μg LAB-nano-Se/egg. The histopathological images of hatched chicks revealed that nano-Se presented normal effects on liver and kidney tissues and restored the parameters as mentioned earlier. To conclude, LAB-nano-Se exhibited beneficial effects in hatched chicks through improving immune and antioxidant activities as well as histopathological effects by using in ovo technique.

Effects of in ovo injection of nano-selenium and nano-zinc oxide and high eggshell temperature during late incubation on antioxidant activity, thyroid and glucocorticoid hormones and some blood metabolites in broiler hatchlings

This experiment was conducted to evaluate the effects of in ovo injection of nano-selenium (Nano-Se) and nano-zinc oxide (Nano-ZnO) and high eggshell temperature (EST) during late incubation on blood parameters of broiler hatchlings. A total of 750 fertile eggs, were weighed and randomly distributed among 5 treatment groups on each of 5 replicate tray levels. The injection was performed on 17 d of incubation. Treatments included of: 1) Eggs not injected and incubated at normal EST (control); 2) Eggs not injected and incubated at high EST; 3) Eggs injected NaCl solution and incubated at high EST (sham); 4) Eggs injected NaCl solution containing 40 µg Nano-Se and incubated at high EST; 5) Eggs injected NaCl solution containing 500 µg Nano-ZnO and incubated at high EST. EST of 37.8ºC (normal) or 38.9ºC (high) was applied from d 19 to 21 of incubation. In ovo injection of Nano-Se and Nano-ZnO significantly increased activity of GSH-Px and SOD and total protein, but decreased the levels of corticosterone, cortisol, T4 and T3 at high EST. Injection of Nano-Se and Nano-ZnO had a significant role in alleviating the negative effects of high temperature incubation and heat stress by increased antioxidant activity and reduced oxidative stress.

Combined adjuvant effect of ginseng stem-leaf saponins and selenium on immune responses to a live bivalent vaccine of Newcastle disease virus and infectious bronchitis virus in chickens

Vaccination with a live bivalent vaccine of Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) is a routine practice in poultry industry in China. This study was designed to evaluate ginseng stem-leaf saponins (GSLS) in combination with selenium (Se) for their adjuvant effect on the immune response to vaccination against NDV and IBV in chickens. A live bivalent vaccine of NDV and IBV was diluted in saline solution containing GSLS or Se or both and used to immunize chickens via a intraocular-and-intranasal route. Results showed that GSLS promoted significantly higher NDV- and IBV-specific antibody responses with the highest antibody response detected in GSLS-Se group. The increased antibody was capable of neutralizing NDV and IBV. In addition, GSLS-Se enhanced lymphocyte proliferation and production of IFN-γ and IL-4. More importantly GSLS-Se was found to promote early production and prolong the duration of the antibody responses. In order to improve the efficacy of vaccination in chicken flocks, the diluent containing GSLS-Se deserves further studies to evaluate its effect on other chicken vaccines.

Role of Selenoproteins in Bacterial Pathogenesis

The trace element selenium is an essential micronutrient that plays an important role in maintaining homeostasis of several tissues including the immune system of mammals. The vast majority of the biological functions of selenium are mediated via selenoproteins, proteins which incorporate the selenium-containing amino acid selenocysteine. Several bacterial infections of humans and animals are associated with decreased levels of selenium in the blood and an adjunct therapy with selenium often leads to favorable outcomes. Many pathogenic bacteria are also capable of synthesizing selenocysteine suggesting that selenoproteins may have a role in bacterial physiology. Interestingly, the composition of host microbiota is also regulated by dietary selenium levels. Therefore, bacterial pathogens, microbiome, and host immune cells may be competing for a limited supply of selenium. Elucidating how selenium, in particular selenoproteins, may regulate pathogen virulence, microbiome diversity, and host immune response during a bacterial infection is critical for clinical management of infectious diseases.

In ovo delivery of various biological supplements, vaccines and drugs in poultry: current knowledge

The technique of delivering various nutrients, supplements, immunostimulants, vaccines, and drugs via the in ovo route is gaining wide attention among researchers worldwide for boosting production performance, immunity and safeguarding the health of poultry. It involves direct administration of the nutrients and biologics into poultry eggs during the incubation period and before the chicks hatch out. In ovo delivery of nutrients has been found to be more effective than post-hatch administration in poultry production. The supplementation of feed additives, nutrients, hormones, probiotics, prebiotics, or their combination via in ovo techniques has shown diverse advantages for poultry products, such as improved growth performance and feed conversion efficiency, optimum development of the gastrointestinal tract, enhancing carcass yield, decreased embryo mortality, and enhanced immunity of poultry. In ovo delivery of vaccination has yielded a better response against various poultry pathogens than vaccination after hatch. So, this review has aimed to provide an insight on in ovo technology and its potential applications in poultry production to deliver different nutrients, supplements, beneficial microbes, vaccines, and drugs directly into the developing embryo to achieve an improvement in post-hatch growth, immunity, and health of poultry. © 2019 Society of Chemical Industry.

In ovo injection of flavanone on bone quality characteristics, biochemical parameters and antioxidant enzyme status of blood in daily chicks

In ovo injection (IOI) of Naringin (N), flavanone was examined on post-hatch blood biochemical parameters, antioxidant status and bone characteristics. Fertile eggs (n = 700) were distributed in seven groups with 100 eggs. On 14th and 17.5th days of incubation, four groups were injected using 15 or 30 mg active ingredient levels of naringin/0.5 ml saline/egg, low and high level, into amnion sac. Controls include sham (injected normal saline, 0.5 ml/egg on day 14 and 17.5th) and un-injected group. IOI of high naringin and saline on 14th day of incubation resulted in lower hatchability and then higher mortality in last week of embryonic life. On day hatch, high levels of injected groups more body weight compared to the control. Chick length was increased at high levels of naringin on day 17.5th compared to control and saline injected. Quality traits of bones were improved in naringin-injected groups compared to control. IOI of naringin influenced thyroid hormones on 14th day of incubation. Naringin groups influenced the Alkaline phosphatase (ALP), Calcium (Ca), superoxide dismutase (SOD), blood biochemical and lipids. Totally, amniotic IOI of naringin in last days of developing embryo may be useful for hatched chick, development of leg long bone or effect on biochemical metabolites by levels of flavanone that it needs more research.

In ovo applications in poultry: A review,

The various methods employed for the in ovo administration of different materials for promoting the health and productivity of poultry are discussed in this review article. The amnion has proven to be an effective site for injection and the timing of in ovo injection has commonly occurred at transfer. However, the volumes and dosages or concentrations of the materials administered vary depending on bird type, egg size, timing and site of injection, incubation system and regimen, and the type of material. Both manual and automated injections have been shown to be effective. Nevertheless, commercial application mandates automation. Materials described in the literature over the past 20 years or more for in ovo use in avian species include vaccines, drugs, hormones, competitive exclusion cultures and prebiotics, and supplemental nutrients. Vaccines approved for in ovo delivery include those for Marek's disease, infectious bursal disease, fowl pox, Newcastle disease, and coccidiosis. Some of the materials listed above have been shown to be viable candidates for enhancing immunity and for promoting embryonic and posthatch development. Several reports have indicated that probiotics may be effectively used to fight intestinal bacterial infections, and folic aid, as well as egg white protein and various amino acids, including L-arginine, L-lysine, L-histidine, HMB, and threonine alone or in combination, have been shown to benefit embryonic development or posthatch performance. Furthermore, CpG oligodeoxynucleotides, vitamins C and E, and thyme and savory have the potential to enhance immunity, carbohydrates can be used to increase tissue glycogen stores, and creatine can be used to promote muscle growth. Trace minerals and vitamin D3 have shown potential to improve bone strength, and potassium chloride may be an effective alternative electrolyte in vaccine diluent. The in ovo application of these and other materials will continue to expand and provide further benefits to the poultry industry.

Application of omics technologies for a deeper insight into quali-quantitative production traits in broiler chickens: A review

The poultry industry is continuously facing substantial and different challenges such as the increasing cost of feed ingredients, the European Union's ban of antibiotic as growth promoters, the antimicrobial resistance and the high incidence of muscle myopathies and breast meat abnormalities. In the last decade, there has been an extraordinary development of many genomic techniques able to describe global variation of genes, proteins and metabolites expression level. Proper application of these cutting-edge omics technologies (mainly transcriptomics, proteomics and metabolomics) paves the possibility to understand much useful information about the biological processes and pathways behind different complex traits of chickens. The current review aimed to highlight some important knowledge achieved through the application of omics technologies and proteo-genomics data in the field of feed efficiency, nutrition, meat quality and disease resistance in broiler chickens.

Effect of sodium selenite and selenium yeast on performance, egg quality, antioxidant capacity, and selenium deposition of laying hens

This study compared the effects of sodium selenite and selenium yeast and their combination on laying performance, egg quality, antioxidant capacity, and selenium (Se) contents in tissues and eggs. Two-hundred-eighty-eight Jing Hong layers that were similar in laying rate (87.5 ± 0.38%) and body weight (1.70 ± 0.02 kg) were randomly distributed into 4 treatments for 11 wk (from 203 d old to 279 d old) with 9 replicates of 8 hens per replicate. The diets (corn-soybean meal diet) were supplemented with 0 [blank control (BC)], 0.3 mg/kg Se from sodium selenite (SS), 0.15 mg/kg Se from sodium selenite and 0.15 mg/kg Se from Se yeast (SS+SY), or 0.3 mg/kg Se from Se yeast (SY). Results showed that the laying rate of the SS+SY group increased significantly (P < 0.05) compared to the BC and SY groups. There were no differences (P > 0.05) in egg quality between the Se-supplemented diets and the BC diet. The serum glutathione peroxidase (GSH-Px) activity was increased (P < 0.01) in hens fed Se-supplemented diets compared to the BC diet. The liver superoxide dismutase (SOD) activity of the SY group was increased significantly (P < 0.05) compared to the BC group. Significant increase (P < 0.01) due to SY supplementation was noted in the serum vitamin E content compared to BC and SS. Layers fed Se-supplemented diets had higher (P < 0.01) contents of Se in the serum, liver, and kidney compared to the BC diet. Compared to BC, Se content in eggs was significantly increased (P < 0.05) by feeding supplementary Se. In conclusion, the effects of SS and Se yeast were approximately equal in promoting antioxidant capacity of laying hens, while Se yeast is easier to deposit into eggs and tissues. The diet with added equal amounts of the 2 sources of Se was more cost effective and affordable than a comparable amount of Se yeast to obtain the promising production performance and nearly similar Se deposition.

Growth-Promoting and Antioxidant Effects of Magnolia Bark Extract in Chickens Uninfected or Co-Infected with Clostridium perfringens and Eimeria maxima as an Experimental Model of Necrotic Enteritis

BACKGROUND

Magnolia tree bark has been widely used in traditional Asian medicine. However, to our knowledge, no studies have been reported investigating the effects of dietary supplementation with magnolia bark extract in chickens.

OBJECTIVE

We tested the hypothesis that dietary supplementation of chickens with a Magnolia officinalis bark extract would increase growth performance in uninfected and Eimeria maxima/Clostridium perfringens co-infected chickens.

METHODS

A total of 168 chickens were fed from hatch either a standard diet or a diet supplemented with 0.33 mg or 0.56 mg M. officinalis bark extract/kg (M/H low or M/H high, respectively) from days 1 to 35. At day 14, half of the chickens were orally infected with E. maxima, followed by C. perfringens infection at day 18 to induce experimental avian necrotic enteritis. Daily feed intake, feed conversion ratio, body weight gain, and final body weight were measured as indicators of growth performance. Serum α1-acid glycoprotein (AGP) concentrations were measured as an indicator of systemic inflammation, and intestinal lesion scores were determined as a marker of disease progression. Transcript levels for catalase, heme oxygenase 1, and superoxide dismutase in the intestine, liver, spleen, and skeletal muscle were measured as indicators of antioxidant status.

RESULTS

Growth performance increased between days 1 and 35 in uninfected and E. maxima/C. perfringens co-infected chickens fed M/H-low or M/H-high diets compared with unsupplemented controls. Gut lesion scores were decreased, whereas AGP concentrations were unchanged, in co-infected chickens fed magnolia-supplemented diets compared with unsupplemented controls. In general, transcripts for antioxidant enzymes increased in chickens fed magnolia-supplemented diets compared with unsupplemented controls, and significant interactions between dietary supplementation and co-infection were observed for all antioxidant enzyme transcript levels.

CONCLUSION

Magnolia bark extract might be useful for future development of dietary strategies to improve poultry health, disease resistance, and productivity without the use of antibiotic growth promoters.

The influence of selenium and selenoproteins on immune responses of poultry and pigs

Selenium is an essential nutrient for poultry and pigs, and is important for a number of physiological processes including regulation and function of the immune system. Through its incorporation into selenoproteins, Se is involved in the regulation of oxidative stress, redox mechanisms, and other crucial cellular processes involved in innate and adaptive immune response. This review provides current knowledge on the mechanisms by which selenium can modulate the resilience to infectious diseases, and how this micronutrient can influence the capacity of the bird or the pig to maintain its productivity during an infectious challenge. In relation to the most frequent and economically important infectious diseases in poultry and pig production, the present paper considers the influence of different selenium sources (organic vs. inorganic Se) as well as dietary concentrations on the immune responses of poultry and pigs with major emphasis on the potential beneficial impact on animal resilience to common infectious diseases.

Protective effect of in ovo treatment with the chicken cathelicidin analog D-CATH-2 against avian pathogenic E. coli

Increasing antibiotic resistance and ever stricter control on antibiotic use are a driving force to develop alternatives to antibiotics. One such strategy is the use of multifunctional Host Defense Peptides. Here we examined the protective effect of prophylactic treatment with the D analog of chicken cathelicidin-2 (D-CATH-2) against a respiratory E. coli infection. Chickens were treated with D-CATH-2 in ovo at day 18 of embryonic development or intramuscularly at days 1 and 4 after hatch. At 7 days of age, birds were challenged intratracheally with avian pathogenic E. coli. Protection was evaluated by recording mortality, morbidity (Mean Lesion Score) and bacterial swabs of air sacs at 7 days post-infection. In ovo D-CATH-2 treatment significantly reduced morbidity (63%) and respiratory bacterial load (>90%), while intramuscular treatment was less effective. D-CATH-2 increased the percentage of peripheral blood lymphocytes and heterophils by both administration routes. E. coli specific IgM levels were lower in in ovo treated animals compared to intramuscular D-CATH-2 treatment. In short, in ovo treatment with the Host Defense Peptide derived D-CATH-2 can partially protect chickens from E. coli infection, making this peptide an interesting starting point to develop alternatives to antibiotics for use in the poultry sector.

Effects of Bacillus licheniformis on the growth performance and expression of lipid metabolism-related genes in broiler chickens challenged with Clostridium perfringens-induced necrotic enteritis

Background

Necrotic enteritis (NE), caused by Clostridium perfringens, has cost the poultry industry $2 billion in losses. This study aimed to investigate the effect of Bacillus licheniformis as dietary supplement on the growth, serum antioxidant status, and expression of lipid-metabolism genes of broiler chickens with C. perfringens-induced NE.

Methods

A total of 240 one-day-old broilers were randomly grouped into four: a negative control, an NE experimental model (PC), chickens fed a diet supplemented with 30 % of fishmeal from day 14 onwards and challenged with coccidiosis vaccine (FC), and NE group supplied with feed containing 1.0 × 10⁶ CFU/g B. licheniformis (BL).

Results

Body weight gain, feed conversion ratio, serum antioxidant status, and lipid-metabolism-gene expression were analyzed. In the PC group, FCR increased significantly whereas serum catalase and glutathione peroxidase activity decreased compared with NC group. Dietary B. licheniformis supplementation improved FCR and oxidative stress in experimental avian NE. Using Bacillus licheniformis as a direct-fed microbial (DFM) could also significantly upregulate catabolism-related genes, namely, peroxisome proliferator-activated receptor-α and carnitine palmitoyltransferase-1, in livers and changed the expression of lipid-anabolism genes.

Conclusion

These results suggested that dietary B. licheniformis supplementation can enhance growth and antioxidant ability, as well as change the expression of genes related to fatty-acid synthesis and oxidation in the livers of NE-infected broilers.

Calcium Montmorillonite-Based Dietary Supplement Attenuates Necrotic Enteritis Induced by Eimeria maxima and Clostridium perfringens in Broilers

Necrotic enteritis (NE) is a poultry disease caused by Clostridium perfringens and characterized by severe intestinal necrosis. The incidence of avian NE has been progressively increasing following the removal of antibiotics from poultry feed. We evaluated the effect of diets supplemented with the thermally-processed clays, calcium montmorillonite (CaMM) on clinical signs, immunopathology, and cytokine responses in broiler chickens using an experimental model of NE consisting of co-infection with Eimeria maxima and C. perfringens. In Trial 1, Ross/Ross chickens were fed from hatch with a normal basal diet or a CaMM-supplemented diet with or without a fermentable fiber, an organic acid, and/or a plant extract, and co-infected with E. maxima and C. perfringens under conditions simulating clinical infection in the field. Chickens fed a diet supplemented with CaMM plus a fermentable fiber and an organic acid had increased body weight gain, reduced gut lesions, and increased serum antibody levels to C. perfringens α-toxin and NetB toxin compared with chickens fed the basal diet alone. Levels of transcripts for interleukin-1β (IL-1β), IL-6, inducible nitric oxide synthase, and tumor necrosis factor-α superfamily-15 were significantly altered in the intestine and spleen of CaMM-supplemented chickens compared with unsupplemented controls (p<0.05). In Trial 2, Cobb/Cobb chickens were fed an unsupplemented diet or a diet supplemented with CaMM or Varium^®, each with a fermentable fiber and an organic acid, and co-infected with E. maxima and C. perfringens under subclinical infection conditions. Compared with unsupplemented controls, broilers fed with CaMM plus a fermentable fiber and an organic acid had increased body weight gain, and reduced feed conversion ratio, mortality, and intestinal lesions, compared with chickens fed an unsupplemented diet (p<0.05). Dietary supplementation of broiler chickens with CaMM plus a fermentable fiber and an organic acid might be useful to control avian NE in the field.

Towards the control of necrotic enteritis in broiler chickens with in-feed antibiotics phasing-out worldwide

Poultry production has undergone a substantial increase compared to the livestock industries since 1970. However, the industry worldwide is now facing challenges with the removal of in-feed antibiotics completely or gradually, as the once well-controlled poultry diseases have re-emerged to cause tremendous loss of production. Necrotic enteritis (NE) is one of the most important diseases which costs the industry over two billion dollars annually. In this paper, we review the progress on the etiology of NE and its control through dietary modifications, pre- and probiotics, short chain fatty acids, and vaccination. The other likely measures resulted in the most advances in the toxin characterization are also discussed. Vaccine strategies may have greater potential for the control of NE mainly due to clearer etiology of NE having been elucidated in recent years with the identification of necrotic enteritis toxin B-like (NetB) toxin. Therefore, the use of alternatives to in-feed antibiotics with a better understanding of the relationship between nutrition and NE, and limiting exposure to infectious agents through biosecurity and vaccination, might be a tool to reduce the incidence of NE and to improve gut health in the absence of in-feed antibiotics. More importantly, the combinations of different measures may achieve greater protection of birds against the disease. Among all the alternatives investigated, prebiotics, organic acids and vaccination have shown improved gastrointestinal health and thus, have potential for the control of NE.

Effects of dietary selenium on host response to necrotic enteritis in young broilers

The effects of dietary supplementation of young broiler chickens with an organic selenium (Se) formulation, B-Traxim Se, on experimental necrotic enteritis (NE) were studied. Chickens treated with three Se doses (0.25, 0.50, 1.00 mg/kg) from hatch were orally challenged with Eimeria maxima at 14 days of age followed by Clostridium perfringens to induce NE. Chickens fed with 0.50 mg/kg Se showed significantly increased body weights and antibody levels against NetB, and significantly reduced gut lesions compared with non-supplemented chickens. However, there were no significant differences in Eimeria oocyst shedding between the Se-treated and non-supplemented groups. Levels of IL-1β, IL-6, IL-8, iNOS, LITAF, TNFSF15, AvBD6, AvBD8, and AvBD13 transcripts were increased in the gut and spleen of at least one of the three Se-treated groups compared with the non-treated group. These results suggest that dietary supplementation of young broilers with Se might be beneficial to reduce the negative consequence of NE.

Towards identifying novel anti-Eimeria agents: trace elements, vitamins, and plant-based natural products

Eimeriosis, a widespread infectious disease of livestock, is caused by coccidian protozoans of the genus Eimeria. These obligate intracellular parasites strike the digestive tract of their hosts and give rise to enormous economic losses, particularly in poultry, ruminants including cattle, and rabbit farming. Vaccination, though a rational prophylactic measure, has not yet been as successful as initially thought. Numerous broad-spectrum anti-coccidial drugs are currently in use for treatment and prophylactic control of eimeriosis. However, increasing concerns about parasite resistance, consumer health, and environmental safety of the commercial drugs warrant efforts to search for novel agents with anti-Eimeria activity. This review summarizes current approaches to prevent and treat eimeriosis such as vaccination and commercial drugs, as well as recent attempts to use dietary antioxidants as novel anti-Eimeria agents. In particular, the trace elements selenium and zinc, the vitamins A and E, and natural products extracted from garlic, barberry, pomegranate, sweet wormwood, and other plants are discussed. Several of these novel anti-Eimeria agents exhibit a protective role against oxidative stress that occurs not only in the intestine of Eimeria-infected animals, but also in their non-parasitized tissues, in particular, in the first-pass organ liver. Currently, it appears to be promising to identify safe combinations of low-cost natural products with high anti-Eimeria efficacy for a potential use as feed supplementation in animal farming.