Effect of dietary selenium on the response of stressed and unstressed chickens to Escherichia coli challenge and antigen

Biological Selenium Nanoparticles in Quail Nutrition: Biosynthesis and its Impact on Performance, Carcass, Blood Chemistry, and Cecal Microbiota

This study was conducted to examine the influence of dietary supplementation of biological nano-selenium (BNSe) on productive performance, hematology, blood chemistry, antioxidant status, immune response, cecal microbiota, and carcass traits of quails. In total, 180 Japanese quails (1 week old) were randomly allocated into four groups, with five replicates of nine chicks each in a complete randomized design. The 1st group was fed a control diet without BNSe, and the 2nd, 3rd, and 4th treatments were fed diets supplemented with BNSe (0.2, 0.4, and 0.6 g /kg feed, respectively). The best level of BNSe in body weight (BW) and body weight gain (BWG) parameters was 0.4 g/kg diet. Feed conversion was improved (P < 0.01) by adding BNSe in quail feed compared with the basal diet without any supplementation. The inclusion of different BNSe levels (0.2, 0.4, 0.6 g/kg) exhibited an insignificant influence on all carcass traits. The dietary addition of BNSe (0.4 and 0.6 g/kg) significantly augmented aspartate aminotransferase (AST) activity (P = 0.0127), total protein and globulin (P < 0.05), white blood cells (WBCs) (P = 0.031), and red blood cells (RBCs) (P = 0.0414) compared with the control. The dietary BNSe supplementation significantly improved lipid parameters, antioxidant and immunological indices, and increased selenium level in the blood (P < 0.05). BNSe significantly increased (P = 0.0003) lactic acid bacteria population number and lowered the total number of yeasts, molds, total bacterial count, E. coli, Coliform, Salmonella, and Enterobacter (P < 0.0001). In conclusion, adding BNSe up to 0.4 and 0.6 g/kg can boost the growth, lactic acid bacteria population number, hematology, immunological indices, antioxidant capacity, and lipid profile, as well as decline intestinal pathogens in growing quail.

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.

Improving selenium accumulation in broilers using Escherichia coli Nissle 1917 with surface-displayed selenite reductase SerV01

Selenium levels have a critical impact on livestock and poultry, and selenium nanoparticles (SeNPs) have shown significant efficiency in supplementation. This study identified a high-efficiency selenite reductase, SerV01, in Staphylococcus aureus LZ-01, which can convert Se₂O₃^2- to SeNPs. Subsequently, SerV01 was introduced into the intestines of the broilers using the surface display-engineered E. coli Nissle 1917 (EcN). The results showed that the engineered bacteria (EcN-IS) significantly increased the selenium content by 0.87 mg kg^-1, 0.52 mg kg^-1, and 6.10 mg L^-1 in the liver, breast muscle, and serum, respectively. With SeNPs + EcN-IS treatment, glutathione peroxidase and thioredoxin reductase levels reached 0.7536 ± 0.03176 U μL^-1 protein and 2.463 ± 0.1685 U μL^-1 protein, respectively. With the modified probiotics, the proportion of beneficial intestinal flora increased, with Lactobacillus and Propionibacterium accounting for 75.85% and 0.19%. This technology provides a novel idea to facilitate the exploitation of selenium in broiler diets and improve antioxidant capability.

Effect of Low-Selenium/High-Fat Diet on Pig Peripheral Blood Lymphocytes: Perspectives from Selenoproteins, Heat Shock Proteins, and Cytokines

The aim of the present study was to clarify the effect of low selenium (Se)/high fat on the mRNA expression of selenoproteins, heat shock proteins (HSPs) and cytokines in pig peripheral blood lymphocytes. Forty crossbred boar piglets with healthy lean body weights of 10 kg were randomly divided into four treatment groups (group C, group L-Se, group H-fat, and group L-Se-H-fat) (n = 10/group) and fed with the corresponding diet for 16 weeks. The pig peripheral blood lymphocytes were extracted, and the mRNA expression of selenoproteins, HSPs, and cytokines was measured. Most mRNA levels for selenoproteins decreased in group L-Se, group H-fat, and group L-Se-H-fat, except Gpx1, Gpx2, Selt, and Selm, which were elevated in group H-fat. At the same time, low-Se/high-fat diet increased the expression of HSPs (HSP40, HSP60, HSP70, and HSP90) and inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, IL-9, iNOS, COX-2, NF-κB, and TNF-α) in group L-Se, group H-fat, and group L-Se-H-fat, and genes in group L-Se-H-fat showed greater increases. Also, low-Se/high-fat diet inhibits the expression of TGF-β1 and IFN-γ. In summary, a low-Se/high-fat diet can cause relevant selenoprotein expression changes and promote the expression of pro-inflammatory factors and HSPs, and low Se enhances the expression of HSPs and inflammation factors induced by high fat. This information is helpful for understanding the effects of low-Se and high-fat diet on pig peripheral blood lymphocytes.

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.

Effects of selenium source and level on growth performance, tissue selenium concentrations, antioxidation, and immune functions of heat-stressed broilers

An experiment is conducted to investigate the effects of selenium (Se) source and level on growth performance, tissue Se concentrations, antioxidation, and immune functions of heat-stressed broilers from 22 to 42 days of age. A total of 210 22-day-old Arbor Acres commercial male chicks were assigned by body weight to one of seven treatments with six replicates of five birds each in a completely randomized design involving a 3 × 2 factorial arrangement plus one Se-unsupplemented basal diet control (containing 0.027 mg of Se/kg). The three Se sources were sodium selenite (Na₂SeO₃), Se yeast, and AMMS Se (Se protein), and the two supplemental Se levels were 0.15 or 0.30 mg Se/kg. All birds were reared under heat-stressed condition (33 ± 1 °C during 0900-1700 hours and 27 ± 1 °C during 1900-0700 hours with a relative humidity of 60-80 %). The results showed that heat-stressed chicks fed Se-supplemented diets had higher (P < 0.10) average daily feed intake, Se concentrations in liver and breast muscle, liver glutathione peroxidase (GSH-Px) activity, serum antibody titers against H5N1(Re-4 strain), H5N1(Re-5 strain) and lower (P < 0.01) mortality compared with the control. Chicks fed the diets supplemented with 0.30 mg/kg of Se had higher (P < 0.05) Se concentrations in liver and breast muscle, liver GSH-Px activity, and serum antibody titer against H5N1 (Re-4 strain) than those fed the diets supplemented with 0.15 mg/kg of Se. Broilers fed the diets supplemented with Se yeast had higher (P < 0.001) Se concentrations in liver and breast muscle than those fed the diets supplemented with Na₂SeO₃ or AMMS Se. However, broilers fed the diets supplemented with AMMS Se had higher (P < 0.05) serum antibody titers against H5N1 (Re-4 strain) and H5N1 (Re-5 strain) than those fed the diets supplemented with Na₂SeO₃. These results indicated that Se yeast was more effective than Na₂SeO₃ or AMMS Se in increasing tissue Se retention; however, AMMS Se was more effective than Na₂SeO₃ or Se yeast in improving immune functions of heat-stressed broilers.

Effects of dietary selenium on tissue concentrations, pathology, oxidative stress, and immune function in common eiders (Somateria mollissima)

Common eiders (Somateria mollissima) were fed added Se (as L-selenomethionine) in concentrations increasing from 10 to 80 ppm in a pilot study (Study 1) or 20 (low exposure) and up to 60 (high exposure) ppm Se in Study 2. Body weights of Study 1 ducks and high-exposure ducks in Study 2 declined rapidly. Mean concentrations of Se in blood reached 32.4 ppm wet weight in Study 1 and 17.5 ppm wet weight in high-exposure birds in Study 2. Mean Se concentrations in liver ranged from 351 (low exposure, Study 2) to 1252 ppm dry weight (Study 1). Oxidative stress was evidenced by Se-associated effects on glutathione metabolism. As Se concentrations in liver increased, Se-dependent glutathione peroxidase activity, glutathione reductase activity, oxidized glutathione levels, and the ratio of hepatic oxidized to reduced glutathione increased. In Study 2, the T-cell-mediated immune response was adversely affected in high-exposure eiders, but ducks in the low-exposure group exhibited evidence of an enhanced antibody-mediated immune response. Gross lesions in high-exposure ducks included emaciation, absence of thymus, and loss of nails from digits. Histologic lesions included severe depletion of lymphoid organs, hepatopathy, and necrosis of feather pulp and feather epithelium. Field studies showed that apparently healthy sea ducks generally have higher levels of Se in liver than healthy fresh-water birds, but lower than concentrations found in our study. Data indicate that common eiders and probably other sea ducks possess a higher threshold, or adverse effect level, for Se in tissues than fresh-water species. However, common eiders developed signs of Se toxicity similar to those seen in fresh-water birds.

Effect of organic selenium in quail diet on its accumulation in tissues and transfer to the progeny

1. The aim of the present study was to investigate the effects on the eggs and hatchlings (up to 2 weeks post-hatch) of feeding a relatively large amount of so-called organic selenium to breeder quail. 2. Two groups of quail (3 families in each group consisting of 4 females and 1 male) were formed at the beginning of their reproductive period. The quail were fed on a commercial maize-based diet containing 0.096 mg/kg feed-derived selenium (Se), supplemented with 0.2 mg/kg selenite (control group) or 0.5 mg/kg organic selenium in the form of Sel-Plex (Alltech Ltd, USA) for 6 months. Eggs were collected at 6 months of age and Se in the egg yolk, egg white and shell was analysed. Five quail at 1, 7 and 14 d post-hatch were killed to provide samples of liver, brain, breast and leg muscles for Se analysis. After egg collection for analysis and incubation, adult quail were killed and liver, kidney, lung, brain, breast and leg muscles were collected for Se analyses. 3. Inclusion of high doses (0.5 mg/kg) of organic Se in the quail diet was associated with a significant increase in Se concentration in all tissues studied of adult quail as well as in egg yolk, egg albumin and eggshell. 4. Increased Se concentration in the quail egg was associated with increased Se concentration in the liver, breast and leg muscles and brain of newly hatched quail. This difference was shown to be significant for 2 weeks post-hatch. Therefore, it has been suggested that the maternal effect of dietary selenium can be seen beyond the hatching time and more emphasis should be given to this effect in future. 5. It was shown that it is possible to produce Se-enriched quail meat and eggs by adding organic selenium to the diet.

Influence of organic selenium on hsp70 response of heat-stressed and enteropathogenic Escherichia coli-challenged broiler chickens (Gallus gallus)

The effect of dietary selenium yeast, a source of organic selenium, on heat shock protein 70 (hsp70) responses, redox status, growth and feed utilization were evaluated either in enteropathogenic Escherichia coli-challenged (EPEC) or in heat-stressed (HS) male broiler chickens grown to 42 days of age. One day-old chicks in experiment 1 were challenged orally with EPEC (10(6) cfu/chicken on day 1 and boosted by water application on days 2, 3, and 4) and fed diets with or without selenium yeast. Body weight (BW), feed conversion ratio (FCR), and total mortality were determined at 42 days of age, and this was followed by collection of ileal tissue for the quantification of total glutathione (TGSH), reduced glutathione (GSH), oxidized glutathione (GSSG), and hsp70 in randomly selected chickens from each treatment. In experiment 2, male broiler chickens were fed diets with or without selenium yeast under a thermoneutral rearing condition. At four weeks of age, blood and hepatic tissue were collected from chickens maintained in the thermoneutral environment and from chickens subjected to HS (40 degrees C for 1 h) and analyzed for TGSH, GSH, GSSG, and hsp70. Selenium yeast improved BW, FCR, and decreased mortality in both control and EPEC-challenged chicks. Selenium yeast significantly attenuated hsp70 expression in EPEC-challenged chickens and in those subjected to HS. The EPEC challenge increased TGSH and GSSG levels and decreased GSH/GSSG ratio. However, GSSG level accumulated in chickens fed diets without selenium supplementation resulting in a lower GSH/GSSG ratio in the selenium yeast-fed group. Heat stress increased GSSG level and decreased GSH/GSSG ratio. Selenium yeast-fed groups maintained higher levels of GSSG before and after HS with a resultant lower GSH/GSSG ratio. The hsp70 response was significantly less in those chickens fed selenium yeast and challenged with either EPEC or HS than in those chickens given no supplemental selenium. The results of this study suggest that selenium yeast supplementation had imparted resistance to oxidative stress associated with enteric bacteria infection and to high temperature exposure. It is believed that the resistance to the stressors was due to an improved redox status of the selenium yeast-fed chickens.

Vitamin and trace mineral content in feed of breeders and their progeny: effects of growth, feed conversion and severity of malabsorption syndrome of broilers

1. A study was conducted to investigate the effects of several vitamins and trace elements chickens and in chickens experimentally infected with malabsorption syndrome (MAS). 2. Vitamins and trace minerals in feed were varied. Breeders received either a basal amount of vitamins and trace minerals (low mix) or an increased amount (high mix). Their progeny also received either a low mix or a high mix. Effects of different breeder and broiler mix combinations on broiler performance, heamatology, spleen weight and humoral response were examined in control chickens. The effects of the different feeds and breeder, broiler combinations at the severity and recovery of MAS infection were also studied. 3. In general, the immune system can be stimulated by addition of vitamins and trace minerals, without affecting the growth potential of the controls. The number of leukocytes increased on d 1 in the broilers descended from breeders receiving high mix. The response to Newcastle disease virus boost was affected by the different amount of vitamins. 4. When breeders received a high mix the number of infiltrating polymorphonuclear leukocytes in the intestine was higher compared with breeders receiving basal amounts of minerals and vitamins. Also the recovery rate of intestinal lesions, cystic crypts of Lieberkühn and villus atrophy, as observed by histopathology, was faster in the groups where the breeders received high mix.

Effect of selenium and vitamin E content of the maternal diet on the antioxidant system of the yolk and the developing chick

1. The effects of selenium and vitamin E supplementation of the maternal diet on their transfer to the egg yolk and tissues of the newly hatched chick and on the development of the antioxidant system in the chick liver in early postnatal life were investigated. 2. One hundred Cobb broiler breeder hens were divided into 10 equal groups and housed in pens at 25 weeks of age. Each hen received 1 of the treatment diets which included 0.2 or 0.4 mg/kg selenium, 40, 100, 200 mg/kg vitamin E or their combination. After 6 weeks, the hens were artificially inseminated once per week. From week 8, eggs were collected and placed in an incubator. After hatching, chicks from each group were reared (under standard commercial conditions) to 10 d of age. The chicks were fed on a standard starter commercial broiler diet. At the time of hatching, and at 5 and 10 days old, 4 chicks from each group were sacrificed and blood, liver and brain were collected for the subsequent biochemical analyses. 3. The inclusion of organic selenium or vitamin E in the commercial diet significantly increased their concentration in the egg and in the liver of 1-d-old chicks obtained from the eggs enriched with these substances. A positive effect of such dietary supplementation was seen at d 5 and d 10 of postnatal development. 4. There was a positive effect of selenium supplementation of the maternal diet on glutathione concentration in the liver of 1-d-old and 5-d-old chicks. A combination of a dietary selenium supplementation with high vitamin E doses further increased glutathione concentration in the liver. Dietary selenium supplementation significantly increased selenium-dependent glutathione peroxidase (Se-GSH-Px) activity in the liver of the 1-d-old and 5-d-old chicks and decreased liver susceptibility to peroxidation. 6. It is concluded that the nutritional status of the laying hen determines the efficiency of the antioxidant system throughout embryonic and early postnatal development of the offspring.

Comparison of the effects of dietary selenium, zinc, and selenium and zinc supplementation on growth and immune response between chick groups that were inoculated with Salmonella and aflatoxin or Salmonella

The effects of four diets (basal diet, Se, Zn, and Se- and Zn-enriched diets) fed to chicks that were administered one of three treatments [Salmonella and aflatoxin inoculation (T1), Salmonella inoculation (T2), or uninoculated (T3)] were investigated for growth and immune responses. We found a significant improvement in growth performance represented by relative body gain (RBG) and feed efficiency (FE), for the Zn- and Se + Zn-enriched diets fed to the T1 and T2 groups. The antibody immune response was significantly improved for the Se enrichment diet in the T1 and T2 groups. The weight of the bursa and thymus, which relate to the level of the immune response, showed significant decreases, whereas the spleen had a significantly increased relative weight (RW) in the T1 group. The variable dietary trace elements supplement increased the thymic RW in the T2 group.