Effects of selenium sources and levels on reproductive performance and selenium retention in broiler breeder, egg, developing embryo, and 1-day-old chick

Selenomethionine Attenuated H2O2-Induced Oxidative Stress and Apoptosis by Nrf2 in Chicken Liver Cells

Earlier studies have shown that selenomethionine (SM) supplements in broiler breeders had higher deposition in eggs, further reduced the mortality of chicken embryos, and exerted a stronger antioxidant ability in offspring than sodium selenite (SS). Since previous studies also confirmed that Se deposition in eggs was positively correlated with maternal supplementation, this study aimed to directly investigate the antioxidant activities and underlying mechanisms of SS and SM on the chicken hepatocellular carcinoma cell line (LMH). The cytotoxicity results showed that the safe concentration of SM was up to 1000 ng/mL, while SS was 100 ng/mL. In Se treatments, both SS and SM significantly elevated mRNA stability and the protein synthesis rate of glutathione peroxidase (GPx) and thioredoxin reductase (TrxR), two Se-containing antioxidant enzymes. Furthermore, SM exerted protective effects in the H2O2-induced oxidant stress model by reducing free radicals (including ROS, MDA, and NO) and elevating the activities of antioxidative enzymes, which performed better than SS. Furthermore, the results showed that cotreatment with SM significantly induced apoptosis induced by H2O2 on elevating the content of Bcl-2 and decreasing caspase-3. Moreover, investigations of the mechanism revealed that SM might exert antioxidant effects on H2O2-induced LMHs by activating the Nrf2 pathway and enhancing the activities of major antioxidant selenoenzymes downstream. These findings provide evidence for the effectiveness of SM on ameliorating H2O2-induced oxidative impairment and suggest SM has the potential to be used in the prevention or adjuvant treatment of oxidative-related impairment in poultry feeds.

Effects of the Number of Crested Cushions in Runzhou White-Crested Ducks on Serum Biochemical Parameters

We investigated the effects of crest cushions in Runzhou white-crested (RWC) ducks. A total of 322 duck eggs were collected for incubation; 286 eggs were fertilized, and 235 RCW ducks were hatched. All the RWC ducks were weighed after 100 days and counted, and the volume of the crest cushion was measured. The number of crest cushions was positively correlated with the body weight, volume of the crest cushion, and distance from the mouth (p < 0.05). The serum Ca, Mg, Fe, Cu, Zn, and Se contents in the multiple-crest-cushion group were significantly higher (p < 0.05), as were the levels of triglycerides, immunoglobulin A, immunoglobulin G, immunoglobulin M, and immunoglobulin D (p < 0.01). The opposite results were seen for glycosylated low-density lipoprotein (p < 0.01). Propionic acid and acetic acid contents differed significantly between the two groups (p < 0.05), as did butyric acid content (p < 0.01), being higher in the multiple-crest-cushion group. Thus, an increase in the number of crest cushions coincided with a change in various serum biochemical indicators. The number of crest cushions might be involved in regulating various mechanisms of RWC ducks and might have an immunoregulatory effect.

The effects of chelated micro-elements feeding in broiler breeder hens and their progeny: A review

Micro-elements are essential for the optimal feeding of broiler hens. Since the chelated micro-elements negatively affect the content of micro- and macro-minerals, there has been a tendency to apply them as an alternative to common mineral forms of micro-elements in poultry diets. This paper reviews the effects of chelates of micro-elements (iron, copper, zinc, manganese, and selenium) on broiler breeder hens' internal and external egg quality and their egg products. The use of chelated micro-elements compared to the mineral forms does not have a significant effect on the performance of broiler breeder flocks, but they have significantly positive effects on the internal and external egg quality of broiler breeder flocks. The chelated micro-elements were also better than mineral resources of micro-elements in improving fertility (0.59%), hatchability (0.81%), and reducing mortality of progeny (2.25%). Chelated micro-elements have no negative impact on blood biochemistry or the immune system of broiler breeder hens and decrease cholesterol (0.84 mmol/l) and triglycerides (0.04 mmol/l) in most cases in comparison with the other mineral forms. Therefore, chelated forms of micro-elements instead of the inorganic mineral forms in diets of broiler breeder hens provide better protection for birds and the environment and also improve egg quality.

Determination of optimal dietary selenium levels by full expression of selenoproteins in various tissues of broilers from 22 to 42 d of age

The current NRC dietary selenium (Se) requirement (0.15 mg/kg) of broilers from 22 to 42 d of age is primarily based on a previous study reported in 1986, which might not be applicable to modern classes of rapidly growing broilers. The present experiment was conducted to determine the optimal dietary Se level for meeting metabolic and functional Se requirements of broilers fed a corn-soybean meal diet from 22 to 42 d of age. A total of 336 Arbor Acres male broilers at 22 d old were randomly assigned to 1 of 6 treatments with 7 replicates and fed a basal corn-soybean meal diet (control, containing 0.014 mg Se/kg) and the basal diet supplemented with 0.10, 0.20, 0.30, 0.40, or 0.50 mg Se/kg from Na₂SeO₃ for 21 d. The results showed that the Se concentrations in plasma, liver, kidney, pancreas, breast and thigh muscles, the activity of glutathione peroxidase (GPX) in plasma, liver and kidney, the mRNA expression levels of Gpx4, selenoprotein (Seleno) h and Selenou in liver, Selenop and Selenoh in kidney, and the protein expression levels of GPX4 in the liver and kidney of broilers were affected (P < 0.05) by supplemental Se level, and increased quadratically (P < 0.05) with the increase of supplemental Se level. The estimates of optimal dietary Se levels were 0.10 to 0.49 mg/kg based on the fitted broken-line or asymptotic models (P < 0.0001) of the above Se concentration indices, and 0.08 to 0.37 mg/kg based on the fitted broken-line, quadratic or asymptotic models (P < 0.007) of the above selenoprotein expression indices. These results indicate that the optimal dietary Se levels would be 0.49 mg/kg to support the maximum Se concentrations and 0.37 mg/kg to support the full expression of selenoproteins in plasma and various tissues of broilers fed a corn-soybean meal diet from 22 to 42 d of age.

Tissue localization of selenium of parental or dietary origin in rainbow trout (Oncorhynchus mykiss) fry using LA-ICP MS bioimaging

In relation to the decrease of selenium (Se) content in aquafeeds, the impact of level and form of parental and dietary Se supplementation was investigated in rainbow trout fry using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP MS) bioimaging. The offspring of rainbow trout broodstock, fed either a control diet without any Se supplementation (0.3 mg Se/kg diet) or a diet supplemented with Se (0.6 mg Se/kg diet) either as sodium selenite or hydroxy-selenomethionine, were sampled at swim-up fry stage or after 11 weeks of cross-feeding. Total body Se levels were influenced by parental Se nutrition in swim-up fry and by direct Se feeding in 11-week fry with higher levels in the Se-supplemented groups compared with the control and the highest levels in the hydroxy-selenomethionine treatment. The Se retention was lower for dietary sodium selenite. Selenomethionine levels increased when Se was provided as hydroxy-selenomethionine. LA-ICP MS maps revealed yolk in swim-up fry and intestine, liver, and kidney in 11-week fed fry as tissues with high Se abundance. In swim-up fry, muscle Se was the highest abundant when parents were fed hydroxy-selenomethionine. In 11-week fed fry, muscle Se abundance was higher in the head part of fry fed both Se-supplemented diets, but only in the tail part of fry fed hydroxy-selenomethionine. Liver Se abundance was higher in fry fed sodium selenite compared with the control diet supporting the hypothesis that tissue Se distribution can be influenced by parental and dietary Se forms and levels.

The mixed application of organic and inorganic selenium shows better effects on incubation and progeny parameters

This experiment aims to study the effects of dietary selenium (Se) sources on the production performance, reproductive performance, and maternal effect of breeder laying hens. A total of 2,112 Hyline brown breeder laying hens of 42 wk of age were selected and randomly divided into 3 groups, with 8 repeats in each group and 88 chickens per repeat. The sources of dietary Se were sodium selenite (SS, added at 0.3 mg/kg), L-selenomethionine (L-SM, added at 0.2 mg/kg), and combination of SS and L-SM (SS 0.15 mg/kg + L-SM 0.15 mg/kg). The pretest period was 7 d, and the breeding period was 49 d. Compared with 0.3 mg/kg SS, the addition of 0.2 mg/kg L-SM in the diet significantly increased the hatchability (P < 0.05) and the Se content (P < 0.05) in egg yolk and chicken embryo tissues and improved the activity of yolk glutathione peroxidase (GSH-px) effectively (P < 0.05). Treatment with 0.2 mg/kg L-SM also reduced the content of yolk malondialdehyde (P < 0.05) and significantly improved the antioxidant performance of 1-day-old chicks, as manifested by increased activity of antioxidant enzymes (GSH-px, total antioxidant capacity and the ability to inhibit hydroxyl radicals) in serum, pectoral, heart, and liver (P < 0.05). This treatment decreased the malondialdehyde content (P < 0.05) and increased the expression of liver glutathione peroxidase 4 and deiodinase 1 mRNA (P < 0.05). Adding L-SM to the diets of chickens increased the hatchability of breeder eggs as well as the amount of Se deposited and antioxidant enzyme activity in breeder eggs and embryos. Compared with SS, L-SM was more effectively transferred from the mother to the embryo and offspring, showing efficient maternal nutrition. For breeder diets, the combination of organic and inorganic Se (0.15 mg/kg SS + 0.15 mg/kg L-SM) is an effective nutrient supplementation technology program for effectively improving the breeding performance of breeders and the antioxidant performance and health level of offspring chicks.

Effects of Selenium-Enriched Yeast on Performance, Egg Quality, Antioxidant Balance, and Egg Selenium Content in Laying Ducks

This study investigated the effects of dietary selenium-enriched yeast (Se yeast) supplementation on the laying performance, egg quality, plasma antioxidant balance, and egg selenium (Se) content in laying Longyan ducks. A total of 480 32-week-old ducks were randomly divided into four dietary treatments, each consisting of six replicates of 20 ducks. The dietary treatments were a control basal diet and basal diets with supplementation of 0.05, 0.15, and 0.25 mg Se/kg via Se yeast. The analyzed Se contents of the four diets were 0.15, 0.21, 0.36, and 0.43 mg Se/kg, respectively. Dietary Se yeast supplementation had no apparent effects on laying performance and egg quality (p > 0.05), but it improved the antioxidant balance of ducks, as inferred by greater glutathione peroxidase and catalase activities, and decreased the malondialdehyde content in plasma of ducks (p < 0.05). It was suggested that the Se content in the basal diet containing 0.15 mg/kg of Se requirement is adequate for productive performance, but not for the antioxidant balance of laying ducks. Besides that, the Se contents in the yolk, albumen, and whole egg increased linearly as the Se supplementation levels increased. With more feeding days, the Se contents in the yolk and whole egg from non-Se-yeast-supplemented ducks increased linearly (p < 0.05), while those from Se-yeast-supplemented ducks showed a quadratic relationship (p < 0.05). In conclusion, the Se content of the basal diet at 0.15 mg/kg was adequate for laying performance and egg quality traits in laying ducks. Dietary Se yeast supplementation is beneficial to improve the antioxidant balance of laying ducks and increase the Se deposition in eggs for producing Se-enriched eggs. Based on the quadratic model or the quadratic broken-line model analyses, supplemental 0.19 mg Se/kg via Se yeast, with a total equivalent of 0.34 mg Se/kg in the diet, could provide the optimum antioxidant balance in laying ducks. Dietary supplementation of 0.25 mg Se/kg via Se yeast, with a total equivalent of 0.40 mg Se/kg in the diet, could lead to achieving the desired Se content in the whole egg.

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.

Effect of Dietary Selenium Supplementation on Growth and Reproduction of Silkworm Bombyx mori L

The effects of selenium (Se) on the growth and reproduction of the Lepidoptera insect, the silkworm, Bombyx mori L were investigated. Initially, the silkworms were divided into eight groups (150 larvae/group) on the basis of feeding with mulberry leaves saturated with different concentrations of Se (25, 50, 100, 125, 150, 175, and 200 μM) and control from the first day of the fourth instar larvae. After feeding, growth and reproductive performance of B. mori L. were investigated with standard techniques used in sericulture. After the data analysis, 50 μM of Se was recognized as the optimal level which positively influenced the growth and production, with prolonged stage of larvae, increased larval, cocoon, and pupal weights, and enhanced number of eggs laid by the female moth as compared to the control group. On the contrary, 200 μM of Se treatment displayed toxic to silkworm and induced significant decrease in the growth, cocoon production, and reproduction. The weight of the cocoon shell, the cocoon shell ratio, number of eggs produced, and fertilization ratio in all the Se-treated groups were lower than the control group. The present study indicated that lower levels of (50 μM) of Se can promote the larval and pupal growth of the B. mori L. resulting in the higher yield of cocoon crop and significantly influencing the fecundity, while high concentration was toxic to silkworm. Our data supply the novel application of Se which could be highly beneficial to sericulture farmers.

Selenium-Yeast Alleviated Inflammatory Damage Caused by Lead via Inhibiting Ras/ERK Pathway and Inflammatory Factors in Chicken Skeletal Muscles

The aim of this study was to investigate the ameliorative effects of selenium-enriched yeast (Se-yeast) on the inflammatory damage induced by lead (Pb) in chicken skeletal muscles. A total of 108 1-day-old broiler chickens were randomly allocated into four groups (n = 27/group): the control group (C group), the Se-yeast-supplemented group (Se group), the lead-treated group (Pb group), and finally the Se- and Pb-combined group (Pb/Se group). The C group was fed with a basic diet comprising 0.049 mg/kg Se and 0.1 mg/kg Pb while the Se group was fed a Se-yeast diet containing 0.30 mg/kg Se and 0.1 mg/kg Pb. Similarly, the Pb group was fed a Pb acetate diet containing 0.049 mg/kg Se and 350 mg/kg Pb while the Pb/Se group was fed with a Se-yeast diet containing 0.30 mg/kg Se and 350 mg/kg Pb. On days 7, 21, and 35 after commencing the experiment, nine chicks belonging to each group were euthanized and the samples were analyzed by employing the techniques of inductively coupled plasma mass spectrometry and real-time quantitative PCR, along with Western blotting. The results indicated that excess Pb increased the nitric oxide concentration, enhanced the activity of inducible nitric oxide synthase (iNOS), and the mRNA levels of interleukin 1β (IL-1β), interleukin 4 (IL-4), interleukin 10 (IL-10), and interferon gamma (IFN-γ) in a time-dependent manner. Further, it was found that Se reduced damage caused by Pb by decreasing the expression of inflammatory factors in chicken skeletal muscles. Taken together, the results from this study provide the theoretical basis for an alleviate effect of Se on Pb-induced inflammatory damage in chicken skeletal muscles, mediated by inhibiting the Ras/extracellular signal-regulated kinase (ERK) pathway and the inflammatory factors.

Effect of Dietary Modulation of Selenium Form and Level on Performance, Tissue Retention, Quality of Frozen Stored Meat and Gene Expression of Antioxidant Status in Ross Broiler Chickens

Simple Summary

Although the importance of usage of selenium as essential trace element in poultry production has been proven, the best source and level has not been fully addressed yet. Three different dietary selenium forms with three different levels were chosen to be added in broiler diet. Met-Se or nano-Se up to 0.6 mg/kg increased their performance and was more efficiently retained in the body than SeS. Frozen stored meat quality was improved in a dose-dependent manner especially with both Met-Se and nano-Se. Nano-Se was more potent than Met-Se, which in turn was more potent than inorganic Se against oxidative stress, which improved the quality of meat under frozen conditions.

Abstract

This study compares between different selenium forms (sodium selenite; SeS, selenomethionine; Met-Se or nano-Se) and levels on growth performance, Se retention, antioxidative potential of fresh and frozen meat, and genes related to oxidative stress in Ross broilers. Birds (n = 450) were randomly divided into nine experimental groups with five replicates in each and were fed diets supplemented with 0.3, 0.45, and 0.6 mg Se/kg as (SeS, Met-Se), or nano-Se. For overall growth performance, dietary inclusion of Met-Se or nano-Se significantly increased (p < 0.05) body weight gain and improved the feed conversion ratio of Ross broiler chicks at the level of 0.45 and 0.6 mg/kg when compared with the group fed the same level of SeS. Se sources and levels significantly affected (p < 0.05) its concentrations in breast muscle, liver, and serum. Moreover, Se retention in muscle was higher (p < 0.05) after feeding of broiler chicks on a diet supplemented with Met-Se or nano-Se compared to the SeS group, especially at 0.6 mg/kg. Additionally, higher dietary levels from Met-Se or nano-Se significantly reduced oxidative changes in breast and thigh meat in the fresh state and after a four-week storage period and increased muscular pH after 24 h of slaughter. Also, broiler’s meat in the Met-Se and nano-Se groups showed cooking loss and lower drip compared to the SeS group (p < 0.05). In the liver, the mRNA expression levels of glutathione peroxidase, superoxide dismutase, and catalase were elevated by increasing dietary Se levels from Met-Se and nano-Se groups up to 0.6 mg/kg when compared with SeS. Therefore, dietary supplementation with 0.6 mg/kg Met-Se and nano-Se improved growth performance and were more efficiently retained than with SeS. Both sources of selenium (Met-Se and nano-Se) downregulated the oxidation processes of meat during the first four weeks of frozen storage, especially in thigh meat, compared with an inorganic source. Finally, dietary supplementation of Met-Se and nano-Se produced acceptable Se levels in chicken meat offered for consumers.

Maternal Selenium and Developmental Programming

Selenium (Se) is an essential trace element of fundamental importance to health due to its antioxidant, anti-inflammatory, and chemopreventive properties, attributed to its presence within at least 25 selenoproteins (Sel). In this review, we describe some of the recent progress, in our understanding, on the impact of maternal Se intake during the periconceptional period on offspring development and health. Maternal nutrition affects the performance and health of the progeny, and both maternal and offspring Se supplementations are essential for the optimal health and antioxidant protection of the offspring. The case of Se in epigenetic programming and early life nutrition is also discussed.

Effects of Maternal Zinc Glycine on Mortality, Zinc Concentration, and Antioxidant Status in a Developing Embryo and 1-Day-Old Chick

This study was conducted to investigate the effects of maternal zinc glycine (Zn-Gly) supplementation as an alternative for zinc sulfate (ZnSO₄) on mortality, zinc (Zn) concentration, and antioxidant status in a developing embryo and 1-day-old chick. Six hundred 39-week-old broiler breeders were randomly assigned to 6 treatments, each treatment including 5 replicates with 20 birds each. Six treatments received a basal diet (control, 24 mg Zn/kg diet) or a basal diet supplemented with ZnSO₄ (80 mg Zn/kg) or Zn-Gly (20, 40, 60, or 80 mg Zn/kg), respectively. The experiment lasted for 8 weeks after a 4-week pre-experiment with a basal diet. At the last week, 100 eggs per replicate were randomly collected for incubation. Compared with the control treatment, Zn supplementation decreased (P < 0.05) embryo mortalities of the late stage and the whole period, increased (P < 0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick, and improved (P < 0.05) antioxidant status in the embryo of d19 and 1-day-old chick. Compared with the ZnSO₄ treatment, 80 mg Zn/kg Zn-Gly treatment significantly decreased (P < 0.05) the late stage embryo mortality and increased (P < 0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick. The 80 mg Zn/kg Zn-Gly treatment significantly increased (P < 0.05) copper-zinc superoxide dismutase activity in d19 embryo and 1-day-old chick, total superoxide dismutase activity in 1-day-old chick, and copper-zinc superoxide dismutase messenger RNA (mRNA) abundance of d9 embryo and 1-day-old chick than that in ZnSO₄ treatment. The liver metallothionein concentration of the developing embryo and 1-day-old chick and its mRNA abundance of d19 embryo were also significantly increased (P < 0.05) in the 80 mg Zn/kg Zn-Gly treatment in comparison with ZnSO₄ treatment. In conclusion, maternal Zn supplementation decreased embryo mortalities of the late stage and the whole period by increasing liver Zn concentration and antioxidant status in d19 embryo and 1-day-old chick, and 80 mg Zn/kg from Zn-Gly treatment was the optimum choice.

The effect of dietary bacterial organic selenium on growth performance, antioxidant capacity, and Selenoproteins gene expression in broiler chickens

Background

Selenium (Se) is an essential trace mineral in broilers, which has several important roles in biological processes. Organic forms of Se are more efficient than inorganic forms and can be produced biologically via Se microbial reduction. Hence, the possibility of using Se-enriched bacteria as feed supplement may provide an interesting source of organic Se, and benefit broiler antioxidant system and other biological processes. The objective of this study was to examine the impacts of inorganic Se and different bacterial organic Se sources on the performance, serum and tissues Se status, antioxidant capacity, and liver mRNA expression of selenoproteins in broilers.

Results

Results indicated that different Se sources did not significantly (P ≤ 0.05) affect broiler growth performance. However, bacterial organic Se of T5 (basal diet +0.3 mg /kg feed ADS18 Se), T4 (basal diet +0.3 mg /kg feed ADS2 Se), and T3 (basal diet +0.3 mg /kg feed ADS1 Se) exhibited significantly (P ≤ 0.05) highest Se concentration in serum, liver, and kidney respectively. Dietary inorganic Se and bacterial organic Se were observed to significantly affect broiler serum ALT, AST, LDH activities and serum creatinine level. ADS18 supplemented Se of (Stenotrophomonas maltophilia) bacterial strain showed the highest GSH-Px activity with the lowest MDA content in serum, and the highest GSH-Px and catalase activity in the kidney, while bacterial Se of ADS2 (Klebsiella pneumoniae) resulted in a higher level of GSH-Px1 and catalase in liver. Moreover, our study showed that in comparison with sodium selenite, only ADS18 bacterial Se showed a significantly higher mRNA level in GSH-Px1, GSH-Px4, DIO1, and TXNDR1, while both ADS18 and ADS2 showed high level of mRNA of DIO2 compared to sodium selenite.

Conclusions

The supplementation of bacterial organic Se in broiler chicken, improved tissue Se deposition, antioxidant status, and selenoproteins gene expression, and can be considered as an effective alternative source of Se in broiler chickens.

The Protective Effects of Different Sources of Maternal Selenium on Oxidative Stressed Chick Embryo Liver

The experiment was conducted to investigate the protective effects of different sources of maternal selenium (Se) on oxidative stressed chick embryo. A total of 270 Lingnan Yellow broiler breeders were randomly allocated into three treatments with five replicates for 18 birds each. Breeders were fed with basal diet (BD) including 0.04 mg/kg Se or BD supplemented with sodium selenite (SS) or selenomethionine (SM) at a level of 0.15 mg Se/kg. The rearing experiment lasted for 8 weeks after an 8-week pre-test. Twenty eggs were collected from each replicate during the last 10-day, then incubated in a commercial incubator. On embryonic 17th, fertile eggs were transferred into 39.5 °C temperature stimulation for 6 h. Afterward, five eggs were randomly selected from each replicate for collecting chick embryo sample. The results showed that Se supplementation in the diet of breeders resulted in lower reactive oxygen species (ROS), heat shock protein 70 (HSP70), malondialdehyde (MDA), carbonyl and 8-hydroxydeoxyguanosine (8-OHdG) concentrations and higher glutathione peroxidase (GPx), total superoxide dismutase (T-SOD), and catalase (CAT) activities in heat stress treated chick embryo (P < 0.05), and ROS, MDA, carbonyl, 8-OHdG concentrations in SM treatment were lower than those in SS treatment (P < 0.05). Se supplementation elevated cellular glutathione peroxidase (GPx1) mRNA level and activity, cytoplasmic thioredoxin reductase (TrxR1) activity and selenoprotein P (SelP) mRNA and protein level (P < 0.05), and maternal SM showed a higher value than maternal SS in upregulating GPx1, TrxR1, and SelP mRNA levels as well as GPx1 and TrxR1 activities or SelP protein level (P < 0.05). This study indicated that maternal Se can enhance antioxidative capacity and reduce ROS concentration and oxidative damage by upregulating the expression of antioxidative selenoprotein, and maternal SM is superior to SS in heat stress treated chick embryo.

Antioxidant systems in chick embryo development. Part 1. Vitamin E, carotenoids and selenium

Chick viability is known to be an important factor determining profitability of the poultry industry. Chick embryo tissues contain a high proportion of highly polyunsaturated fatty acids in the lipid fraction and therefore need antioxidant defence. The antioxidant system of the developing embryo and newly hatched chick includes the antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase), water-soluble antioxidants (ascorbic acid, taurine, carnitine, glutathione, etc.), fat-soluble antioxidants (vitamin E, carotenoids, coenzyme Q) as well as selenium (Se). In fact, the high levels of endogenous antioxidants within the egg and embryonic tissues can clearly serve as a major adaptive mechanism for the protection of the tissue during the oxidative stress experienced at hatching. It has been shown that among different nutrients in the maternal diet which could significantly affect chick embryo development and their viability in the early posthatch life, natural antioxidants have been suggested to play a central role. Our data indicate that increased supplementation of the maternal diet can substantially increase concentrations of vitamin E, carotenoids (especially canthaxanthin) and Se in developing chick tissues and significantly decrease susceptibility to lipid peroxidation being effective nutritional tools to deal with various commercial stresses in poultry production.

Regulation of selenoprotein P concentration and expression by different sources of selenium in broiler breeders and their offspring

An 8-wk experiment using 180 Lingnan Yellow broiler breeders was conducted to investigate the effect of different sources of Se on the concentration and gene expression of selenoprotein P (SEPP1) in broiler breeders and their offspring. After receiving a low-Se basal diet for 8 wk, broiler breeders were randomly allocated to 3 treatments (6 replicates per treatment) and fed corn-soy-based diets supplemented with 0.15 mg/kg of Se from sodium selenite (SS), Se-enriched yeast (SY), and selenomethionine (SM), respectively. Fertile eggs from different replicates were collected during the last week of the experiment and then incubated in different incubator trays in the same incubator. The concentrations and mRNA levels of SEPP1 were determined in liver and kidney of broiler breeders and their offspring, as well as the serum SEPP1 concentration. Compared with SS, both SY and SM significantly increased (P < 0.05) the concentration and mRNA level of SEPP1 in 1-d-old chicks. In broiler breeders, the serum and liver SEPP1 concentrations were notably increased by the use of organic Se (P < 0.05), whereas no differences were found in the kidney. Moreover, the SEPP1 mRNA level in the liver was remarkably elevated (P < 0.05) in organic Se treatments, but also no differences were observed in the kidney. Results of this study indicate that the use of organic Se (SY or SM) in maternal diets is very effective for increasing the concentration and mRNA level of SEPP1, especially in their offspring. No differences between SY and SM were observed.

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.