Effects of selenium yeast level in diet on carcass and meat quality, tissue selenium distribution and glutathione peroxidase activity in ducks

Selenized non-Saccharomyces yeasts and their potential use in fish feed

Selenium (Se) is a vital trace element, essential for growth and other biological functions in fish. Its significance lies in its role as a fundamental component of selenoproteins, which are crucial for optimal functioning of the organism. The inclusion of Se in the diets of farmed animals, including fish, has proved invaluable in mitigating the challenges arising from elemental deficiencies experienced in captivity conditions due to limitations in the content of fishmeal. Supplementing diets with Se enhances physiological responses, particularly mitigates the effects of the continuous presence of environmental stress factors. Organic Se has been shown to have higher absorption rates and a greater impact on bioavailability and overall health than inorganic forms. A characteristic feature of yeasts is their rapid proliferation and growth, marked by efficient mineral assimilation. Most of the selenized yeasts currently available in the market, and used predominantly in animal production and aquaculture, are based on Saccharomyces cerevisiae, which contains selenomethionine (Se-Met). The object of this review is to highlight the importance of selenized yeasts. In addition, it presents metabolic and productive aspects of other yeast genera that are important potential sources of organic selenium. Some yeast strains discussed produce metabolites of interest such as lipids, pigments, and amino acids, which could have applications in aquaculture and further enrich their usefulness.

Nanoselenium attenuates renal ischemia-reperfusion injury in rats

Using selenium (Se) nanoparticles has received attention in recent years because of their therapeutic benefits due to their anticancer, antioxidant, anti-inflammatory, and anti-diabetic effects. This research was conducted to evaluate the possible protective impact of nano-Se on renal unilateral ischemia/reperfusion injury (uIRI) in adult male Wistar rats. Using clamping of the left renal pedicle within 45 min uIRI was induced. The animals were randomly divided into nine groups of control, nano-Se (0.25, 0.5, and 1 mg/kg bw/day) alone, uIRI control, and uIRI rats administrated with nano-Se. At 30 days after treatment, the animals were sacrificed to be assessed biochemically and histopathologically. Nano-Se in uIRI groups have significantly decreased serum creatinine, urea levels, renal histological damage, and increased antioxidant status. Also, our findings demonstrated that the administration of nano-Se caused a significant decrease in the immunoreactivity level of the epidermal growth factor (EGF) and EGFR expression (EGF receptor) in the renal tissue of the uIRI rats. Therefore, nano-Se possesses renoprotective effects, and this effect might be attributable to its antioxidant and free radical scavenger effects. These renoprotective effects may depend on the decreased EGF immunoreactivity level and EGFR expression in the kidney tissue and improve the structure of the kidney tissue. Thus, our research provided biochemical and histological data supporting the potential clinical use of nano-Se for the treatment of certain kidney disorders.

Selenium-Rich Black Soldier Fly Supplementation Enriches Serum Indexes and Egg Selenium Content in Laying Hens

A certain amount of selenium (Se) is usually added to the diet of laying hens to improve the quality and nutritional value of eggs. The present study was carried out to investigate the effect of selenium-rich black soldier fly (BSF) supplementation in diets on laying production performance, egg quality, serum indexes, and egg selenium content of Hy-line variety brown laying hens. A total of 288 at 49-week-old healthy laying hens were divided into 3 treatment groups with 6 replicates per group and 16 hens per replicate using a single-factor completely randomized design. Treatments consisted of (1) control (basal diet without supplemental Se), (2) 0.30 mg/kg supplemental Se, (Se as sodium selenite, SS), and (3) 0.30 mg/kg supplemental Se (Se as selenium-rich black soldier fly, SE-BSF). Laying performance was not affected by dietary Se. There was no effect of selenium-rich BSF on egg quality (P > 0.05). The contents of malonaldehyde (MDA) were significantly reduced (P < 0.05). On the contrary, dietary Se supplementation increased the activity of superoxide dismutase (SOD, P < 0.05) and catalase (CAT, P < 0.05) and increased the concentration of reduced glutathione (P < 0.05). In addition, selenium-rich BSF supplementation significantly increased the Se content of eggs (P < 0.05). These results indicate that Se supplementation did not affect laying production performance and egg quality of laying hens, but the supplementation could improve antioxidant capacity and increased the Se content of eggs.

Effects of Selenium Dietary Yeast on Growth Performance, Slaughter Performance, Antioxidant Capacity, and Selenium Deposition in Broiler Chickens

Selenium (Se) yeast, a bioavailable form of selenium, exhibits enhanced bioavailability due to its unique organic matrix and superior metabolic availability compared to the inorganic selenium sources. This study aims to evaluate the effects of Se yeast on the growth performance, slaughter performance, antioxidant capacity, and Se deposition in broiler chickens. A total of 264 1-day-old male AA broilers (38.7 ± 0.1 g) were randomly assigned to four treatment groups, with six replicates of 11 chickens per replicate. The broilers were fed a basal diet or a diet supplemented with 0.1, 0.2, and 0.4 mg/kg Se yeast. The experiment lasted for 42 days. Although the results showed that Se yeast did not significantly improve the growth performance of broilers, it did significantly decrease the abdominal fat ratio. Additionally, supplementation of Se yeast significantly improved the antioxidant capacity of broilers. The quadratic regression models were used to simulate the relationship between Se content in the feed and Se deposition in broiler tissues. The regression equations were as follows: pectoral muscle, Y = 2.628X - 0.340X2 - 0.592 (R2 = 0.927); leg muscle, Y = 2.317X - 0.272X2 - 0.490 (R2 = 0.937); liver, Y = 3.357X - 0.453X2 - 0.493 (R2 = 0.961); kidney, Y = 4.084X - 0.649X2 + 0.792 (R2 = 0.932). Based on these findings, the Se deposition in broiler tissues can be predicted by the Se content of the additive, which is of great significance for the precise production of Se-enriched functional chicken products.

Biogenic Selenium Nanoparticles and Their Anticancer Effects Pertaining to Probiotic Bacteria—A Review

Selenium nanoparticles (SeNPs) can be produced by biogenic, physical, and chemical processes. The physical and chemical processes have hazardous effects. However, biogenic synthesis (by microorganisms) is an eco-friendly and economical technique that is non-toxic to human and animal health. The mechanism for biogenic SeNPs from microorganisms is still not well understood. Over the past two decades, extensive research has been conducted on the nutritional and therapeutic applications of biogenic SeNPs. The research revealed that biogenic SeNPs are considered novel competitors in the pharmaceutical and food industries, as they have been shown to be virtually non-toxic when used in medical practice and as dietary supplements and release only trace amounts of Se ions when ingested. Various pathogenic and probiotic/nonpathogenic bacteria are used for the biogenic synthesis of SeNPs. However, in the case of biosynthesis by pathogenic bacteria, extraction and purification techniques are required for further useful applications of these biogenic SeNPs. This review focuses on the applications of SeNPs (derived from probiotic/nonpathogenic organisms) as promising anticancer agents. This review describes that SeNPs derived from probiotic/nonpathogenic organisms are considered safe for human consumption. These biogenic SeNPs reduce oxidative stress in the human body and have also been shown to be effective against breast, prostate, lung, liver, and colon cancers. This review provides helpful information on the safe use of biogenic SeNPs and their economic importance for dietary and therapeutic purposes, especially as anticancer agents.

Effects of selenium yeast and jujube powder dietary supplements on conformational and functional properties of post-mortem chicken myofibrillar protein

The aim of the study was to evaluate the effects of selenium yeast and jujube powder on the structure and functional properties of post-mortem myofibrillar protein (MP) in white feather broilers. Changes in the structure (surface hydrophobicity, secondary structure, and tertiary structure), functional properties (solubility, turbidity, emulsifying, and foaming characteristics), and gel properties (gel strength, springiness, and water-holding capacity) of the MPs of white feather broiler, which were fed with different concentrations of selenium yeast or/and jujube powder (selenium yeast: 0,0.3, and 0.6 mg/kg; jujube powder: 8% to replace corn) for 42 days, were determined at 0, 24, and 72 h post-mortem. The results showed that with increasing concentrations of selenium yeast and jujube powder in the diet, the α-helix content, solubility, emulsification, and foaming of post-mortem chicken MP increased significantly (P < 0.05). The gel strength, springiness, and water-holding capacity of MP also increased, but the differences between the treatment groups were not significant (P > 0.05). In addition, the β-folding content and turbidity of MP decreased significantly (P < 0.05). Both the increase in selenium yeast levels and the addition of jujube powder improved the structural integrity and functional properties of MP. The best improvement effect was found in the combination group of high-dose selenium yeast and jujube powder, and there were significant interactions between them in the indices of α-helix, β-folding, turbidity, emulsification, and foam stability of MP. In conclusion, supplementing diets with seleniumyeast and jujube powder could maintain the structural stability of MPs in post-mortem chicken breast, leading to good functional properties. The results of this study may provide new insights into the effects of pre-slaughter feeding on post-mortem muscle MP conformation control and quality improvement.

Potential Mechanism and Effects of Different Selenium Sources and Different Effective Microorganism Supplementation Levels on Growth Performance, Meat Quality, and Muscle Fiber Characteristics of Three-Yellow Chickens

A trial was conducted to investigate the effects of different Se sources, including sodium selenite (S-Se) and selenium yeast (Y-Se) and different effective microorganism (EM) addition levels on growth performance, meat quality, and muscle fiber characteristics of three-yellow chickens and its potential mechanism. A total of 400 birds were randomly distributed into 4 groups (S-Se, S-Se + EM, Y-Se, and Y-Se + EM groups) consisting of a 2 × 2 factorial arrangement. The main factors were the source of Se (I_Se = inorganic Se: 0.2 mg/kg S-Se; O_Se = organic Se: 0.2 mg/kg Y-Se) and the level of EM (H_EMB = high EM: 0.5% EM; Z_EMB = low EM: 0% EM). Each treatment had 5 replicates and each replicate consisted of 20 broiler chickens. The trial lasted for 70 days. The results showed that, in breast muscle, the broiler chickens fed O_Se source decreased the pH_24h, drip loss, shear force, perimeter, cross-sectional area, and diameter, but increased the a24h* and density compared with the broiler chickens fed I_Se source (p < 0.05); broiler chickens supplied with H_EMB level decreased the cross-sectional area and diameter, but increased the pH_24h, a24h,* and density compared with the broiler chickens supplied with Z_EMB level (p < 0.05). In thigh muscle, O_Se source and H_EMB level also could improve the meat quality and change muscle fiber characteristics of broiler chickens (p < 0.05). Meat quality was correlated with the muscle fiber characteristics (p < 0.05). O_Se source and H_EMB level could regulate the expression levels of muscle fiber-relative genes in the breast and thigh muscles (p < 0.05). In conclusion, O_Se source and H_EMB level could improve the meat quality of the breast and thigh muscles of three-yellow chickens by changing the muscle fiber characteristics, and they changed the muscle fiber characteristics by regulating the expression levels of muscle fiber-relative genes.

Effect of supplementing hydroxy selenomethionine on meat quality of yellow feather broiler

This study was conducted to evaluate the effect of supplementing hydroxy selenomethionine (OH-SeMet) on performance, selenium (Se) deposition in the breast muscle, quality and oxidative stability, and expression of selenoprotein encoding genes of breast meat of the native slow-growing yellow-feathered broiler birds. A total of 375 one-day-old local yellow male birds were randomly assigned into 5 dietary treatments, supplemented with Se 0.0, 0.2, 0.4, 0.6, and 0.8 mg/kg in the form of OH-SeMet. Each treatment consisted of 5 replicates and each replicate had 15 birds, the birds were fed on basal diet containing corn and soybean meal, and the experiment lasted for 63 d. The results showed that dietary Se supplementation linearly increased (P < 0.001) Se contents in both serum and muscle, no significant changes (P > 0.05) were observed on growth performance, yield of breast, meat color, and intramuscular fat deposition of the breast muscle. Dietary Se addition improved water-holding capacity, the pH_24h value, and tenderness of breast muscle, evidenced by a linear decreases of shear force (P < 0.05), accompanied by lower thiobarbituric acid reactive substances and higher glutathione reductase activity. The mRNA abundance of selenoprotein encoding genes also responded to dietary Se levels. It is concluded that, dietary supplementation with OH-SeMet improved muscular Se deposition and meat quality of the native yellow birds, with enhanced antioxidant capability and regulation in selenogenome.

Review: Production factors affecting poultry carcass and meat quality attributes

Poultry meat mainly comes from standard production system using high growth rate strains reared under indoor intensive conditions. However, it is possible to find also different alternative systems using outdoor extensive rearing conditions and slow-growing lines. These different production systems can affect carcass and meat quality. In this review, quality has been broken down into six properties: commercial, organoleptic, nutritional, technological, sanitary and image, the latter covering the ethical, cultural and environmental dimensions associated with the way the meat is produced, as well as its origin and being particularly valued in many quality labels. The quality of meat is built and can deteriorate along the continuum from the conception of the animal to the fork. Our review details the different factors implicated in the determinism of poultry meat properties and pinpoints critical periods, such as the preslaughter and slaughter periods, and key factors, such as the feeding regimen, via its direct effect on the fatty acid profile, the antioxidant and volatile compound contents, and indirect effects mediated via the growth rate of the bird. Our review also highlights potential antagonisms between different dimensions of quality. The genetic selection for breast meat yield, for example, has been effective in producing carcasses with higher meat yield, but resulting since a decade in the increased occurrence of quality defects and myopathies (white striping, wooden breast, spaghetti meat and deep pectoral disease). Outdoor access has positive effects on the image and nutritional properties (through its effect on the fatty acid profile of meat lipids), but it increases the exposition risk to environmental contaminants and pathologies (parasites, virus, bacteria); it also increases the variability in meat quality linked to the variability of animal performance and slaughter age. The orientation towards more agro-ecological low-input farming systems may present benefits for the image and nutritional properties, but also risks for the commercial (low carcass weight and low breast yield, irregularity in supply), organoleptic (stronger flavour, less tender and darker colour of the meat) and in terms of variability of the different properties that constitute quality. Efforts should be made in the future to better take into account the various dimensions of quality, in consumer information, payment to farmers and genetic selection.

RETRACTED: Growth performance, carcass characteristics, and selected meat quality traits of two strains of Pekin duck reared in intensive vs semi-intensive housing systems

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). The article has been retracted at the request of the Editor-in-Chief. The article was derived from the thesis of one of the authors: Utjecaj genotipa i sustava drzanja na kvalitetu pacjeg mesa H. Mahmutovic Faculty of Agriculture of Osijek UDK 637.5’65: 636.082(043) view (nsk.hr) The thesis was not acknowledged in the article, contrary to requirement by the journal. Concerns raised by the Thesis supervisors (Drs. G. Kralik and Z. Kralik) were shared with the corresponding author and the different institutions involved. The analysis performed by the journal concluded that the published article and the thesis report a different number of replicates per treatment (n= 6 vs n=3) and differ in their description of batches of animals delivered at the experimental facilities and starting the experiment at different times (n=1 vs n=3). Overall the analysis of the evidence provided indicates that the statistical model applied to the data is not appropriate to the experimental design. As a result, the study is not reproducible, and findings cannot be considered as reliable. Authorship issues were identified. The thesis supervisors were not associated to the publication. Several co-authors (M. Starčević*, H. Mahmutović, N. Glamočlija, M. Bašić, R. Mitrović, R. Marković, M. Bošković, M.Ž. Baltić) recognised that their contributions were erroneously declared so their authorship remains questionable. The Financial Support Statement is incomplete. Evidence was provided that other sources also contributed to financing the study. Apologies are offered to readers of the journal for any inconvenience this may cause.

Increasing selenium supplementation to a moderately-reduced energy and protein diet improves antioxidant status and meat quality without affecting growth performance in finishing pigs

BACKGROUND

Along with economic development and living standards' improvement, more and more attention has been converted from satisfying meat quantity to pursuing meat quality.

RESEARCH PURPOSE

This study was conducted to evaluate the effects of increasing selenium (Se) supplementation to a moderately-reduced energy and protein diet (MREP) on growth performance, antioxidant status, meat quality in finishing pigs.

BASIC PROCEDURES

A total of 144 "Duroc × Landrace × Yorkshire" pigs with the average body weight of 75 ± 1 kg were randomly allotted to 3 dietary treatments with six replicates per treatment and eight pigs per replicate. The 3 experimental diets were as follows: (1) Normal energy and protein (NEP) +0.2 mg/kg Se diet (14.02 MJ/kg DE, 14% CP and 0.2 mg/kg Se as selenite sodium), (2) MREP +0.2 mg/kg Se diet (13.60 MJ/kg DE, 13% CP and 0.2 mg/kg Se as selenite sodium), and (3) MREP +0.5 mg/kg Se diet (13.60 MJ/kg DE, 13% CP, 0.2 mg/kg Se as selenite sodium, and 0.3 mg/kg Se as Se-enriched yeast). The study lasted for 45 days.

MAIN FINDINGS

The results show that there were no differences for growth performance, antioxidant status and meat quality of finishing pigs between NEP +0.2 mg/kg Se group and MREP +0.2 mg/kg Se group (P＞0.05). However, compared to pigs from MREP +0.2 mg/kg Se group, pigs from MREP +0.5 mg/kg Se group had greater Se concentration, GSH-Px activity and GSH concentration, but lower MDA concentration in serum (P＜0.05). Also, pigs from MREP +0.5 mg/kg Se group had greater Se concentration, T-AOC, and SOD activity, but lower MDA concentration in loin compared with pigs from MREP +0.2 mg/kg Se group (P＜0.05). As for meat quality, pigs from MREP +0.5 mg/kg Se group had greater a* value (relative redness) at 45 min and 24 h in loin compared with pigs from MREP +0.2 mg/kg Se group (P＜0.05). Compared to pigs from MREP +0.2 mg/kg Se group, pigs from MREP +0.5 mg/kg Se group had lower MDA concentration of fresh pork during a simulated retail display at 0, 1, 2, 4, 6 and 7 day (P＜0.05).

PRINCIPAL CONCLUSIONS

In conclusion, increasing selenium supplementation to a moderately-reduced energy and protein diet improved antioxidant status and meat quality without affecting growth performance in finishing pigs. (New Aspects) The present study provided a nutritional strategy for reducing feed costs and improving pork quality without influencing growth performance in finishing pigs.

Growth performance, carcass composition, leg bones, and digestive system characteristics in Pekin duck broilers fed a diet diluted with whole wheat grain

A total of 270 Pekin ducks were reared for 49 d to determine the effect of feeding a diluted complete commercial wheat grain diet on live weight, feed intake and conversion, carcass, leg bone, and digestive system traits. Different feeding regimes had a significant effect on the body weight of the ducks aged 35 d and the feed conversion ratio in the period between days 22 and 35 of rearing. Dilution of a complete commercial diet with whole wheat grain had no significant influence on the final live weight (day 49), feed intake, and feed conversion ratio during the entire rearing period. Ducks fed a diet with whole wheat grain had a significantly higher dressing percentage after higher percentage of pectoral muscles, skin with subcutaneous fat, abdominal fat, as well as a significantly lower percentage of carcass remainders at the age of 49 d. Dilution of a complete commercial diet with whole wheat grain had no impact on the length of the respective intestinal sections nor on the weight and percentage share of gizzard, liver, heart, and spleen. However, it significantly lowered the fracture strength of the tibiotarsus, and decreased some dimensions of the femur and tibiotarsus.

Effects of selenium source and level in diet on glutathione peroxidase activity, tissue selenium distribution, and growth performance in poultry

Today, a few differing sources of selenium (Se), i.e. inorganic, organic, and nano forms of Se, are used as feed supplements for poultry. Published research indicates that nano-Se and organic Se possess comparable efficiency to inorganic Se in increasing GSH-Px activity of plasma and various tissues, but they deposit at higher rates in various tissues. However, there are principal differences in absorption mechanisms, metabolism, and efficiency of these three forms of Se. The aim of this review was to analyze the available literature on the effects of different Se sources and levels in the diet on glutathione peroxidase (GSH-Px) activity, tissue Se distribution and growth performance in poultry. Higher levels of Se increase GSH-Px activity in the body, but this reaches a plateau even if Se concentrations in diet increase further, while the deposition of Se in tissues increases as Se content in diet increases. In addition, many studies have shown the positive effects of adding Se to diet on growth performance in poultry. Optimal Se supplementation is necessary not only for good poultry health but also to ensure and preserve meat quality during storage and to provide human beings with this microelement.

Effects of Selenium Yeast in Combination with Boron on Muscle Growth and Muscle Quality in Broilers

The effect of selenium yeast in combination with boron on both growth and quality of the muscle in broilers was investigated. A total of 600 one-day-old Arbor Acres broilers were randomly divided into five groups with 120 broilers per group (6 replicates per group). The control group received a basal diet, and experimental groups I-IV received the same basal diet supplemented with 0.3 mg/kg selenium yeast and different doses of boron (0, 5, 10, and 15 mg/kg, respectively). The experiment was conducted for 42 days. Breast and thigh muscles were harvested and muscle quality were examined on day 21 and day 42 of the experiment. Compared to the control group, at 21 days of age, the thigh muscle weight and index were significantly increased in broilers of experimental group II (all P < 0.05); however, the drip loss and shear force of breast and thigh muscle were significantly decreased (P < 0.05). At 42 days of age, the breast muscle weight and index as well as the breast and thigh muscle water holding capability had significantly increased in broilers of experimental group II (all P < 0.05); the breast and thigh muscle drip loss, cooking loss and shear force, and thigh muscle fiber diameter were significantly reduced (all P < 0.05). Breast and thigh muscle fibers were tightly arranged with small cross-sectional areas in broilers of experimental group II. These results suggest that supplementation of 0.3 mg/kg selenium yeast in combination with 5 mg/kg boron in the basal diet can promote muscle growth and improved muscle quality in broilers.

Assessment of the application for renewal of authorisation of selenomethionine produced by Saccharomyces cerevisiae NCYC R397 for all animal species

The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the application for renewal of authorisation of organic form of selenium produced by Saccharomyces cerevisiae NCYC R397 (Alkosel^®) for all animal species. The FEEDAP Panel has delivered two opinions (on 2007 and 2016) on the safety and efficacy of the additive. The additive is characterised as organic selenium mainly selenomethionine (63%); it was initially authorised in 2007 with a content of 2,000–2,400 mg Se/kg (97–99 % of organic selenium) and in 2017 the authorisation was further amended to introduce a selenium range of 2,000–3,500 mg Se/kg. Additionally, in 2013, the initial authorising Regulation was modified to introduce a maximum supplementation selenium from this additive in feed (0.2 mg Se from Alkosel^®/kg feed). The evidence provided indicates that the additive currently in the market complies with the conditions of authorisation. No new evidence was found that would make the FEEDAP Panel reconsidering its previous conclusions in the safety for target species, consumers and environment. In particular, the Panel confirms that the use of Alkosel^® in animal nutrition does not pose a risk to consumers provided that the maximum selenium supplementation of 0.2 mg/kg feed from Alkosel^® is not exceeded, yet respecting the maximum total selenium in feed of 0.5 mg/kg. Data on the characterisation of the additive and studies on skin/eyes effects led the Panel reconsider the safety for the user, concluding that Alkosel^® is (i) hazardous upon inhalation, (ii) non‐irritant to skin and considered irritant for the eyes and mucosae, and (iii) a dermal sensitiser and likely a respiratory sensitiser. A recommendation regarding the denomination of the additive under assessment was proposed by the Panel.

The effects of dietary Selenium-yeast level on glutathione peroxidase activity, tissue Selenium content, growth performance, and carcass and meat quality of broilers

The present study was conducted to assess effects of selenium (Se)-yeast supplementation on glutathione peroxidase activity, Se levels in tissues, growth performance, carcass, and meat composition in broilers. A total of 275 one-d-old Cobb 500 broilers of both sexes were randomly allotted to 1 of 5 treatments during a 42-d period. The 5 treatments differed only in Se content: group 1 had no additional Se (background only); groups 2, 3, and 4 received 0.3 mg/kg of added Se from the beginning of the trial until d 21, whereas in the second half of the study (from d 22 to 42), these groups received 0.3, 0.6, and 0.9 mg/kg of added Se, respectively; and group 5 received 0.9 mg/kg of Se for the entire experimental period. At the end of the study, the control group showed significantly lower (P < 0.01) glutathione peroxidase activity in blood plasma compared to Se-supplemented groups. Regarding Se concentration in various tissues, the groups receiving Se yeast showed higher plasma, feces, and meat Se contents than the control group (P < 0.01). Supplementation of Se improved broilers' body weight, weight gain and feed conversion ratio (P < 0.01). Dressing percentage was lower in the control group and the group with 0.3 mg/kg of added Se compared to other experimental groups (0.6 and 0.9 mg/kg of dietary Se). The proportion of less valuable carcass parts (wings and legs) was higher (P < 0.01) in the group fed the basal diet compared to groups supplemented with 0.9 mg/kg of Se. Initial and ultimate pH values differed among experimental groups (P < 0.05). Supplementation of Se improved the broiler's antioxidative resistance, growth performance, carcass quality, and chemical composition of meat.

Selenium Analysis and Speciation in Dietary Supplements Based on Next-Generation Selenium Ingredients

Selenium is essential for humans and the deficit of Se requires supplementation. In addition to traditional forms such as Se salts, amino acids, or selenium-enriched yeast supplements, next-generation selenium supplements, with lower risk for excess supplementation, are emerging. These are based on selenium forms with lower toxicity, higher bioavailability, and controlled release, such as zerovalent selenium nanoparticles (SeNPs) and selenized polysaccharides (SPs). This article aims to focus on the existing analytical systems for the next-generation Se dietary supplement, providing, at the same time, an overview of the analytical methods available for the traditional forms. The next-generation dietary supplements are evaluated in comparison with the conventional/traditional ones, as well as the analysis and speciation methods that are suitable to reveal which Se forms and species are present in a dietary supplement. Knowledge gaps and further research potential in this field are highlighted. The review indicates that the methods of analysis of next-generation selenium supplements should include a step related to chemical species separation. Such a step would allow a proper characterization of the selenium forms/species, including molecular mass/dimension, and substantiates the marketing claims related to the main advantages of these new selenium ingredients.

Effects of dietary selenium-yeast concentrations on growth performance and carcass composition of ducks

The aim of the present study was to assess effects of selenium (Se)-yeast diet supplementation on performance and carcass composition in ducks. The study was performed on 240 1-day old ducklings of the same origin (Cherry Valley hybrid), during a 49-day period, which were fed diets supplemented with the following four different levels of Se yeast (ALKOSEL® R397): groups with Se at 0 mg/kg of the diet as-fed, 0.2 mg/kg, 0.4 mg/kg and 0.6 mg/kg. Growth performance (bodyweight, daily weight gain, daily feed intake, feed-conversion ratio) and carcass characteristics (hot and cold carcass weight, chilling losses, dressing percentage, carcass cut yields, and percentage of tissues in breast and thighs with drumsticks) of the ducks were determined. Animals fed high-Se diets (0.4 mg/kg) had higher (P &lt; 0.05) final bodyweight and daily weight gain (from 15 to 49 days) compared with those fed diets with inadequate (0 mg/kg) or with supranutritional (0.6 mg/kg) Se levels. Ducks fed only with basal diet showed a higher (P &lt; 0.05) feed-conversion ratio (from 15 to 49 days) compared with those supplemented with Se at 0.4 mg/kg and 0.6 mg/kg. Dressing percentage was higher (P &lt; 0.01) in the control group (69.50%) than in the group with Se added at 0.6 mg/kg (66.85%). The weights of basic cuts from the duck carcasses did not significantly differ among compared groups. Moreover, the percentage of skin with subcutaneous fat in breast and thighs with drumsticks increased in Se-supplemented groups compared with the control group, while the opposite was determined with the percentage of muscle. It was concluded that a diet containing 0.4 mg of added Se per kilogram produced the greatest growth-performance results in ducks.