Rumen Microorganisms Decrease Bioavailability of Inorganic Selenium Supplements

The effect of supplementary selenium source on apparent and true absorption, retention, performance, and selenium status in lactating Holstein cows

Selenium is an essential trace mineral for dairy cattle and can be provided in the diet in various forms that may differ in bioavailability. The objective of this study was to determine how source of Se affects animal performance, Se status, retention, and apparent and true absorption. Multiparous Holstein cows (n = 24; 597 ± 49 kg of BW) were blocked by DIM (161 ± 18) and randomly assigned to receive 0.3 mg Se/kg of DM (100% of National Academies of Sciences, Engineering, and Medicine requirements) of either organic Se (ORG; selenized yeast) or inorganic Se (INO; sodium selenite). The Se premix was top dressed on a common TMR fed daily and mixed into the top 15 cm directly before feeding. Following an 11-wk adaptation period, cows received simultaneous infusions of an intraruminal isotope dose of 77Se in the same chemical form as the premix, and an intravenous dose of 82Se in an inorganic form. Infusions were followed by a 4-d period of blood and rumen fluid sampling, and total collection of feces, urine, and milk. Daily DMI (23 ± 0.6 kg), milk yield (35 ± 1.2 kg), and serum Se (0.11 ± 0.003 µg/g) were not different between treatments during the adaptation period, but milk Se concentrations were greater for ORG compared with INO. Serum 77Se maximum concentration and area under the curve (AUC) were not different between treatments for 72 h following infusion, but rumen fluid 77Se AUC was higher for ORG than INO. Apparent absorption (64% ± 1.4%), and retention (44% ± 1.5%) of the 77Se dose did not differ between treatments. True absorption was calculated using 82Se enrichment in serum and feces and was determined to be 69% ± 1.3% and did not differ between treatments. Fecal excretion of the 77Se dose was not different between treatments (36% ± 1.4%), but ORG had lower urinary excretion and higher milk excretion compared with INO. These results indicate that organic Se resulted in greater Se concentration of milk and lower urinary Se excretion into the environment, but absorption, Se status, and performance of the cow were not affected by Se source at this supplementation level.

Integrated Blood Transcriptome and Multi-Tissue Trace Mineral Analyses of Healthy Stocker Cattle Fed Complexed or Inorganic Trace Mineral Supplement

Supplementing trace minerals is common in managing bovine respiratory disease (BRD) in post-weaned cattle; however, its influence on host immunity and metabolism in high-risk cattle remains unclear. We aimed to assess the impact of three supplementation programs on liver and serum trace element concentrations and blood gene expression. Fifty-six high-risk beef steers were randomly assigned to one of three groups over 60 days: (1) sulfate-sourced Cu, Co, Mn, and Zn (INR), (2) amino acid-complexed Cu, Mn, Co, and Zn (AAC), or (3) AAC plus trace mineral and vitamin drench (COMBO). Serum and liver biopsies for Cu, Co, Mn, and Zn at d0, d28, and d60 were analyzed from cattle free of BRD (n = 9 INR; n = 6 AAC; n = 10 COMBO). Differences and correlations of mineral concentrations were analyzed via generalized linear mixed models and Spearman's rank coefficients, respectively (p < 0.05). Whole blood RNA samples from healthy cattle (n = 4 INR; n = 4 AAC; n = 4 COMBO) at d0, d13, d28, d45, and d60 were sequenced and analyzed for differentially expressed genes (DEGs) via glmmSeq (FDR < 0.05), edgeR (FDR < 0.10), and Trendy (p < 0.10). Serum and liver Cu and Co concentrations increased over time in all groups, with higher liver Cu in COMBO (487.985 μg/g) versus AAC (392.043 μg/g) at d60 (p = 0.013). Serum and liver Cu concentrations (ρ = 0.579, p = 6.59 × 10-8) and serum and liver Co concentrations (ρ = 0.466, p = 2.80 × 10-5) were linearly correlated. Minimal gene expression differences were found between AAC versus COMBO (n = 2 DEGs) and INR versus COMBO (n = 0 DEGs) over time. AAC versus INR revealed 107 DEGs (d13-d60) with increased traits in AAC including metabolism of carbohydrates/fat-soluble vitamins, antigen presentation, ATPase activity, and B- and T-cell activation, while osteoclast differentiation and neutrophil degranulation decreased in AAC compared to INR. Our study identifies gene expression differences in high-risk cattle fed inorganic or amino acid-complexed mineral supplements, revealing adaptive immune and metabolic mechanisms that may be improved by organically sourced supplementation.

Combined Supplementation of Two Selenium Forms (Organic and Inorganic) and Iodine in Dairy Cows' Diet to Obtain Enriched Milk, Cheese, and Yogurt

This study evaluated the effects of dietary supplementation in dairy cows with two Se forms (organic and inorganic) and I at the maximum levels permitted in the European Union, with the aim to obtain naturally enriched milk and derived products. A total of 20 Holstein Friesian cows in lactation were fed 2 diets for 64 days: a control diet with a supply of 0.57 mg of inorganic Se and 0.57 mg of I per kg of ration in dry matter (DM), and an experimental diet (SeI) with a supply of 0.34 mg of inorganic Se, 0.23 mg of organic Se, and 5.68 mg of I per kg of ration in DM. The SeI diet did not modify the performance or, in general, the metabolic profile of cows. Se and I levels in milk were affected by diet type and time of measurement (p < 0.01). Thus, a marked increase of both microminerals was evident between the beginning and the end of the test, when the SeI diet was administered. For Se, this increase ranged from 1.95 to 3.29 μg/100 g of milk; and for I, from 19.69 to 110.06 μg/100 g of milk. The SeI diet increased (p < 0.01) the Se and I content in the cheese, reaching levels of 16.4 μg/100 g for Se and 269.7 μg/100 g for I. An increase in I was observed in yogurt from the SeI diet (p < 0.001). The supplementation of two forms of Se and I in the cows' ration, at the levels evaluated, produced milk and dairy products enriched in these microelements without altering their quality parameters. However, a responsible intake of these products is necessary to avoid risks of deficiencies or excesses that could negatively affect the health of consumers.

Selenium volatilization in plants, microalgae, and microorganisms

The augmented prevalence of Se (Se) pollution can be attributed to various human activities, such as mining, coal combustion, oil extraction and refining, and agricultural irrigation. Although Se is vital for animals, humans, and microorganisms, excessive concentrations of this element can give rise to potential hazards. Consequently, numerous approaches have been devised to mitigate Se pollution, encompassing physicochemical techniques and bioremediation. The recognition of Se volatilization as a potential strategy for mitigating Se pollution in contaminated environments is underscored in this review. This study delves into the volatilization mechanisms in various organisms, including plants, microalgae, and microorganisms. By assessing the efficacy of Se removal and identifying the rate-limiting steps associated with volatilization, this paper provides insightful recommendations for Se mitigation. Constructed wetlands are a cost-effective and environmentally friendly alternative in the treatment of Se volatilization. The fate, behavior, bioavailability, and toxicity of Se within complex environmental systems are comprehensively reviewed. This knowledge forms the basis for developing management plans that aimed at mitigating Se contamination in wetlands and protecting the associated ecosystems.

Organic and Inorganic Selenium Compounds Affected Lipidomic Profile of Spleen of Lambs Fed with Diets Enriched in Carnosic Acid and Fish Oil

The purpose of our study was to investigate the effect of 0.35 mg Se/kg basal diet (BD) (Se as sodium selenate (Se6) and yeast rich in seleno-methionine (SeYe)) and 0.1% carnosic acid (CA) supplementation to the diet containing 1% fish oil (F-O) and 2% rapeseed oil (R-O) on the contents of fatty acids (FA), malondialdehyde (MDA), tocopherols (Ts), and total cholesterol (TCh) in lambs' spleens. A total of 24 male lambs (4 groups per 6 animals) have been fed: the control diet-the basal diet (BD) enriched in F-O and R-O; the CA diet-BD enriched in F-O, R-O, and CA; the SeYeCA diet-BD enriched in F-O, R-O, CA, and SeYe; the Se6CA diet-BD enriched in F-O, R-O, CA, and Se6. Dietary modifications affected the profiles of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids in spleens. The SeYeCA and Se6CA diets increased the docosapentaenoic acid preference in Δ4-desaturase; hence, a higher content of docosahexaenoic acid was found in the spleens of SeYe- or Se6-treated lambs than in spleens of animals receiving the CA and control diets. The SeYeCA and Se6CA diets increased the concentration ratio of n-3long-chain PUFA (n-3LPUFA) to FA (n-3LPUFA/FA) in spleens compared to the control and CA diets. The content of n-3PUFA was higher in the spleens of Se6 treated lambs than in spleens of animals receiving the SeYeCA, CA, and control diets. The Se6CA diet increased the content of c9t11CLA in the spleen compared to the control, CA, and SeYeCA diets. Experimental diets reduced the level of atherogenic FA, the content ratios of n-6PUFA/n-3PUFA and n-6LPUFA/n-3LPUFA, and improved the content ratio of MUFA/FA and the value of the hypocholesterolemic/hypercholesterolemic FA ratio in the spleen in comparison with the control diet. The experimental diets supplemented with SeYe or Se6 increased levels of TCh and Ts in spleens in comparison with the CA and control CA diets. The present studies documented that Se6, SeYe, and CA influenced the metabolism of FA, Ts, and cholesterol in spleens.

Total Selenium Level and Its Distribution between Organs in Beef Cattle in Different Selenium Status

The aim of this study was to determine the Se concentration in the main tissues of beef cattle and to evaluate the differences in tissue distribution between animals with different selenium status. Selenium concentration was determined in the serum, longissimus dorsi muscle, semitendinosus muscle, kidney, heart, liver, spleen and lungs of cows, heifers and beef bulls, using spectrofluorimetric method. Despite receiving supplementation, 55.6% animals demonstrated an optimal Se level, while 44.4% were deficient. The mean serum Se concentration was significantly higher (p < 0.05) in animals with a normal Se status than in Se-deficient animals. Differences in Se tissue distribution were observed between Se-deficient animals and those with normal Se status. The organs most susceptible to Se deficiency are the semitendinosus muscle, lungs, heart and liver. In both normal and Se-deficient animals, significantly higher Se concentrations were observed in the kidney than other organs (p < 0.05), and the lowest in the muscles. As Se deficiencies can be found among supplemented animals, the level of Se should be monitored in beef cattle in order to detect possible Se deficiencies, which may have negative health effects for animals and reduce the value of animal products as a source of Se in the human diet.

The Effect of Dietary Supplementation with Probiotic and Postbiotic Yeast Products on Ewes Milk Performance and Immune Oxidative Status

The administration of yeast products as feed additives has been proven to beneficially affect animal productivity through energy, oxidative, and immune status improvement. This study evaluated a combination of Saccharomyces cerevisiae live yeast (LY) with yeast postbiotics (rich in mannan-oligosaccharides (MOS) and beta-glucans) and selenium (Se)-enriched yeast on ewes' milk performance and milk quality, energy and oxidative status, and gene expression related to their immune system during the peripartum period. Ewes were fed a basal diet (BD; F:C = 58:42 prepartum and 41:59 postpartum) including inorganic Se (CON; n = 27), the BD supplemented with a LY product, and inorganic Se (AC; n = 29), as well as the combination of the LY, a product of yeast fraction rich in MOS and beta-glucans, and organic-Se-enriched yeast (ACMAN; n = 26) from 6 weeks prepartum to 6 weeks postpartum. The β-hydroxybutyric acid concentration in the blood of AC and ACMAN ewes was lower (compared to the CON) in both pre- and postpartum periods (p < 0.010). Postpartum, milk yield was increased in the AC and ACMAN Lacaune ewes (p = 0.001). In addition, the activity of superoxide dismutase (p = 0.037) and total antioxidant capacity (p = 0.034) measured via the 2,2-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) method was increased in the blood plasma of the ACMAN postpartum. Higher ABTS values were also found (p = 0.021), while protein carbonyls were reduced (p = 0.023) in the milk of the treated groups. The relative transcript levels of CCL5 and IL6 were downregulated in the monocytes (p = 0.007 and p = 0.026 respectively), and those of NFKB were downregulated in the neutrophils of the ACMAN-fed ewes postpartum (p = 0.020). The dietary supplementation of ewes with yeast postbiotics rich in MOS and beta-glucans, and organic Se, improved energy status, milk yield and some milk constituents, and oxidative status, with simultaneous suppression of mRNA levels of proinflammatory genes during the peripartum period.

Evaluation of Trace Mineral Sources

Several trace mineral sources, including inorganic, numerous organic, and hydroxychloride sources, are available for dietary supplementation or inclusion in a free-choice supplement. Inorganic forms of copper and manganese differ in their bioavailability. Although research results have been variable, organic and hydroxychloride trace minerals are generally considered more bioavailable than inorganic sources. Research indicates that fiber digestibility is lower in ruminants fed sulfate trace minerals compared with hydroxychloride and some organic sources. Compared with free-choice supplements, individual dosing with rumen boluses or injectable forms ensures that each animal receives the same quantity of a trace mineral.

Trace Mineral Nutrition of Sheep

Trace mineral nutrition of sheep often focuses on their greater susceptibility to copper toxicosis due to a lesser biliary excretion ability compared with other ruminants. Our understanding of sheep trace mineral requirements has improved for most elements allowing for a factorial approach to determining daily requirement instead of a dietary concentration. Forage trace mineral content is influenced by many factors making issues of trace mineral supplementation geographic-dependent. Oral delivery of trace elements is a preferred supplementation method, and this can be achieved through free choice trace mineralized salt or direct dietary incorporation.

Advances in selenium supplementation: From selenium-enriched yeast to potential selenium-enriched insects, and selenium nanoparticles

Selenium (Se) is an essential micronutrient that plays an important role in animal and human development and physiological homoeostasis. This review surveys the role of Se in the environment, plants and animal bodies, and discusses data on Se biofortification with different sources of supplementation, from inorganic to organic forms, with special focus on Se-enriched yeast (Se-yeast). Although Se-yeast remains one of the main sources of organic Se, other emerging and innovative sources are reviewed, such as Se-enriched insects and Se-nanoparticles and their potential use in animal nutrition. Se-enriched insects are discussed as an option for supplying Se in organic form to livestock diets. Se-nanoparticles are also discussed, as they represent a more biocompatible and less toxic source of inorganic Se for animal organisms, compared to selenite and selenate. We also provide up to date information on the legal framework in the EU, USA, and Canada of Se that is contained in feed additives. From the scientific evidence available in the literature, it can be concluded that among the inorganic forms, sodium selenite is still one of the main options, whereas Se-yeast remains the primary organic form. However, other potential sources such as Se-enriched insects and Se-nanoparticles are being investigated as they could potentially combine a high bioavailability and reduced Se emissions in the environment.

Efficacy of feeding hydroxy-selenomethionine on plasma and milk selenium in mid-lactation dairy cows

In this study, we aimed to determine the amount of Se transferred to milk and blood of mid- to late-lactation dairy cows when supplemental Se from hydroxy-selenomethionine (OH-SeMet) was fed compared with an unsupplemented group and a group supplemented with a seleno-yeast (SY). Twenty-four lactating Holstein cows (178 ± 43 d in milk) were used in a complete randomized block design for 91 d (7-d covariate period and 84-d treatment period). Treatments were (1) basal diet with an analyzed Se background of 0.2 mg of Se per kg as-fed (control); (2) basal diet + 0.3 mg of Se/kg as-fed from SY (SY-0.3); (3) basal diet + 0.1 mg of Se/kg as-fed from OH-SeMet (OH-SeMet-0.1); and (4) basal diet + 0.3 mg of Se/kg as-fed from OH-SeMet (OH-SeMet-0.3). During the trial, plasma and milk were analyzed for total Se, and plasma was analyzed for glutathione peroxidase activity. The mean plasma and milk Se concentrations exhibited the same relationship, where OH-SeMet-0.3 resulted in the highest values (142 µg/L of plasma and 104 µg/kg of milk), followed by SY-0.3 (134 µg/L and 85 µg/kg), OH-SeMet-0.1 (122 µg/L and 67 µg/kg), and the control group had the lowest values (120 µg/L and 50 µg/kg). The increment of Se in milk induced by OH-SeMet-0.3 (+54 µg/kg) was 54% higher than that induced by SY-0.3 (+35 µg/kg). Additionally, dietary supplementation of 0.2 mg/kg Se from OH-SeMet in the total mixed ration was estimated to be similar to 0.3 mg/kg Se from SY in the total mixed ration when considering the level of Se in the milk. There was no difference in plasma glutathione peroxidase activity between groups; however, OH-SeMet-0.3 significantly decreased somatic cell count. The results confirmed that supplementation with organic Se increases milk and plasma Se concentrations. Moreover, when administered at the same level of supplementation, OH-SeMet was shown to be more efficient than SY in improving milk quality by increasing Se content and decreasing milk somatic cell count.

Differentially Expressed Genes and Signalling Pathways Regulated by High Selenium Involved in Antioxidant and Immune Functions of Goats Based on Transcriptome Sequencing

The objective of this study is to observe the effect of high selenium on the antioxidant and immune functions of growing goats based on transcriptome sequencing. Eighteen goats were randomly divided into three groups: (1) the control (CON) group was fed a basal diet, and (2) the treatment 1 group (LS) and treatment 2 group (HS) were fed a basal diet with 2.4 and 4.8 mg/kg selenium-yeast (SY), respectively. The results indicate that HS treatment significantly (p < 0.05) increased the apparent digestibility of either extract and significantly increased (p < 0.05) total antioxidant capacity, whereas it significantly (p < 0.05) decreased plasma aspartate aminotransferase and malondialdehyde relative to the control group. The LS treatment had significantly (p < 0.05) increased glutathione S-transferase and catalase compared to CON. A total of 532 differentially expressed genes (DEGs) between the CON and HS were obtained using transcriptome sequencing. Kyoto Encyclopedia of Genes and Genomes analysis identified upregulated (p < 0.05) DEGs mainly related to vascular smooth muscle contraction, alpha-linolenic acid metabolism, biosynthesis of unsaturated fatty acids, the VEGF signalling pathway, and proteoglycans in cancer; downregulated (p < 0.05) DEGs mainly related to the NOD-like receptor signalling pathway, influenza A, cytokine-cytokine receptor interaction, haematopoietic cell lineage, and African trypanosomiasis. Ontology analyses of the top genes show that the identified DEGs are mainly involved in the regulation of granulocyte macrophage colony-stimulating factor production for biological processes, the external side of the plasma membrane for cellular components, and carbohydrate derivative binding for molecular functions. Seven genes are considered potential candidate genes for regulating antioxidant activity, including selenoprotein W, 1, glutathione peroxidase 1, glutathione S-transferase A1, tumour necrosis factor, tumour necrosis factor superfamily member 10, tumour necrosis factor superfamily member 8, and tumour necrosis factor superfamily member 13b. The experimental observations indicate that dietary supplementation with 4.8 mg/kg SY can enhance antioxidant and immune functions by improving muscle immunity, reducing the concentrations of inflammatory molecules, and modulating antioxidant and inflammatory signalling pathways in growing goats.

Effects of organic and inorganic selenium on selenium bioavailability, growth performance, antioxidant status and meat quality of a local beef cattle in China

Selenium (Se) is an essential nutrient with multiple health benefits to humans and animals. Cattle generally require dietary Se supplementation to meet their daily requirements. The two main forms of dietary Se in cattle are organic Se and inorganic Se. Data comparing the health and productivity effects of organic Se and inorganic Se on cattle are still insufficient, and it is necessary to conduct more research to evaluate the bioavailability, nutritional value, deposition, and body functions of Se sources in different breeds and physiological stages of cattle raised in areas with different Se levels. The objectives of this study were to determine the effects of organic and inorganic sources of Se on plasma biochemical indices, Se bioavailability, deposition in body tissues and organs, growth performance, antioxidant capacity and meat quality of beef cattle raised in Se-deficient areas. Fifteen Chinese Xiangzhong Black beef cattle with an average weight of 254.5 ± 8.85 kg were assigned to three dietary groups. The three groups were fed the same basal ration and supplemented with either an inorganic [sodium selenite (SS)] or organic [selenomethionine (SM) or Se-enriched yeast (SY)] source of Se (0.1 mg/kg dry matter) for 60 days. At the end of the experiment, three cattle from each group were randomly selected and slaughtered, and samples were collected from tissues and organs for analysis. The results revealed that growth performance, slaughter performance, Se content of tissues and organs, meat quality characteristics including chemical composition, pH_45min, pH_24h, drip loss, and cooking losses did not differ (p > 0.05) due to supplementation of the different organic and inorganic sources of Se. SM and SY were more effective in increasing (p < 0.05) immunoglobulin M (IgM) concentrations in the blood and reducing (p < 0.05) malondialdehyde (MDA) content in the longissimus dorsi than SS. In conclusion, organic Se is more effective than inorganic Se in improving the immune and antioxidant capacity of Chinese Xiangzhong Black beef cattle.

Comparison of coated and uncoated trace elements on growth performance, apparent digestibility, intestinal development and microbial diversity in growing sheep

The suitable supplement pattern affects the digestion and absorption of trace minerals by ruminants. This study aimed to compare the effects of coated and uncoated trace elements on growth performance, apparent digestibility, intestinal development and microbial diversity in growing sheep. Thirty 4-month-old male Yunnan semi-fine wool sheep were randomly assigned to three treatments (n = 10) and fed with following diets: basal diet without adding exogenous trace elements (CON), basal diet plus 400 mg/kg coated trace elements (CTE, the rumen passage rate was 65.87%) and basal diet plus an equal amount of trace elements in uncoated form (UTE). Compared with the CON group, the average daily weight gain and apparent digestibility of crude protein were higher (P < 0.05) in the CTE and UTE groups, while there was no difference between the CTE and UTE groups. The serum levels of selenium, iodine and cobalt were higher (P < 0.05) in the CTE and UTE groups than those in the CON group, the serum levels of selenium and cobalt were higher (P < 0.05) in the CTE group than those in the UTE group. Compared with the CON and UTE groups, the villus height and the ratio of villus height to crypt depth in duodenum and ileum were higher (P < 0.05) in the CTE groups. The addition of trace minerals in diet upregulated most of the relative gene expression of Ocludin, Claudin-1, Claudin-2, ZO-1, and ZO-2 in the duodenum and jejunum and metal ion transporters (FPN1 and ZNT4) in small intestine. The relative abundance of the genera Christensenellaceae R-7 group, Ruminococcus 1, Lachnospiraceae NK3A20 group, and Ruminococcaceae in ileum, and Ruminococcaceae UCG-014 and Lactobacillus in colon was higher in the CTE group that in the CON group. These results indicated that dietary trace mineral addition improved the growth performance and intestinal development, and altered the structure of intestinal bacteria in growing sheep. Compared to uncoated form, offering trace mineral elements to sheep in coated form had a higher absorption efficiency, however, had little effect on improving growth performance of growing sheep.

Selenomethionine protected BMECs from inflammatory injury and oxidative damage induced by Klebsiella pneumoniae by inhibiting the NF-κB and activating the Nrf2 signaling pathway

Klebsiella pneumoniae (K. pneumoniae) is one of the main environmental pathogens causing bovine mastitis. The incidence of bovine mastitis caused by K. pneumoniae is increasing worldwide. Selenium is an essential trace element that has multiple physiological functions, such as antioxidant and anti-inflammatory activities. Therefore, this study aimed to verify whether selenomethionine (SeMet) could contribute to alleviating the inflammatory injury and oxidative damage induced by K. pneumoniae. Bovine mammary epithelial cells were cultured in vitro and pretreated with 4 μM SeMet before being infected with K. pneumoniae. Western blot analysis was used to detect the expression of the related proteins in the NF-κB and Nrf2 signaling pathways. The gene expression levels of IL-1β, IL-6, IL-8, TNF-α, Nrf2, Keap1, NQO-1 and HO-1 were detected using RT-qPCR. The levels of MDA, GSH-PX, SOD, CAT and T-AOC were detected by commercial assay kits. Flow cytometry was used to determine the level of intracellular ROS, and immunofluorescence was used to detect the nuclear localization of Nrf2 protein. Briefly, SeMet downregulated the phosphorylation levels of IκBα and p65 proteins and the gene expression levels of IL-1β, IL-6, IL-8 and TNF-α were also decreased. Moreover, the protein and gene expression levels of Nrf2, NQO-1 and HO-1 were upregulated, and the nuclear expression of Nrf2 protein was also promoted, which enhanced the activity of antioxidant enzymes. In conclusion, SeMet protected BMECs from inflammatory injury and oxidative stress induced by K. pneumoniae by inhibiting the NF-κB and activating the Nrf2 signaling pathway.

Effects of replacing inorganic salts of trace minerals with organic trace minerals in pre- and postpartum diets on feeding behavior, rumen fermentation, and performance of dairy cows

Our objectives were to evaluate the effects of complete replacement of supplementary inorganic salts of trace minerals (STM) by organic trace minerals (OTM) in both pre- and postpartum diets on feeding behavior, ruminal fermentation, rumination activity, energy metabolism, and lactation performance in dairy cows. Pregnant cows and heifers (n = 273) were blocked by parity and body condition score and randomly assigned to either STM or OTM diets at 45 ± 3 d before their expected calving date. Both groups received the same diet, except for the source of trace minerals (TM). The STM group was supplemented with Co, Cu, Mn, and Zn sulfates and Na selenite, whereas the OTM group was supplemented with Co, Cu, Mn, and Zn proteinates and selenized yeast. Treatments continued until 156 days in milk and pre- and postpartum diets were formulated to meet 100% of recommended levels of each TM in both treatments, taking into consideration both basal and supplemental levels. Automatic feed bins were used to assign treatments to individual cows and to measure feed intake and feeding behavior. Rumination activity was monitored by sensors attached to a collar from wk -3 to 3 relative to calving. Blood metabolites were evaluated on d -21, -10, -3, 0, 3, 7, 10, 14, 23, and 65 relative to calving. Ruminal fluid samples were collected using an ororuminal sampling device on d -21, 23, and 65 relative to calving, for measurement of ruminal pH and concentration of volatile fatty acids. Cows were milked twice a day and milk components were measured monthly. Cows supplemented with OTM tended to have longer daily feeding time (188 vs. 197 min/d), and greater dry matter intake (DMI; 12.9 vs. 13.3 kg), and had a more positive energy balance (3.6 vs. 4.2 Mcal/d) and shorter rumination time per kg of dry matter (DM; 40.1 vs. 37.5 min/kg of DM) than cows supplemented with STM during the prepartum period. In the postpartum period, OTM increased DMI in multiparous cows (24.1 vs. 24.7 kg/d) but not in primiparous cows (19.1 vs. 18.7 kg/d). The difference in DMI of multiparous cows was more evident in the first 5 wk of lactation, when it averaged 1 kg/d. Milk yield was not affected by treatment in multiparous cows (44.1 vs. 44.2 kg/d); however, primiparous cows supplemented with OTM had lesser yields than primiparous cows supplemented with STM (31.9 vs. 29.8 kg/d). Cows supplemented with OTM had a greater percentage of protein in milk (3.11 vs. 3.17%), reduced concentration of nonesterified fatty acids in serum (0.45 vs. 0.40 mmol/L), and rumination activity (30.1 vs. 27.8 min/kg of DM) than cows supplemented with STM. At the end of the transition period, cows supplemented with OTM had reduced molar proportion of acetate, reduced pH, and tended to have a greater concentration of total volatile fatty acids in ruminal fluid. In conclusion, complete replacement of STM by OTM caused modest changes in rumen fermentation, feeding behavior, energy metabolism, and performance of dairy cows, improving postpartum DMI in multiparous cows and reducing circulating levels of nonesterified fatty acids. The pre-absorptive effects of TM source and the parity specific responses on performance warrant further research.

Monthly Dynamics of Plasma Elements, Hematology, Oxidative Stress Markers, and Hormonal Concentrations in Growing Male Shiba Goats (Capra hircus) Reared in Tokyo-Japan

Simple Summary

During the first stage of an animal’s life, various physiological alterations with the concomitant development of different body organs occur. This period is also accompanied by different kinds of stressors, including, but not limited to, the stress of weaning, metabolic change, and peri-puberty changes in reproductive functions. Shiba goats, the main goat breed in Japan, are not commonly used as food animals. However, male Shiba goats largely contribute to reproductive and cardiology research activities, as well as being used for educational purposes for elementary school children. The physiological data regarding laboratory measurements in Shiba goats are lacking, especially at a young age. In this study, we investigated the age-related changes in hematology, plasma mineral concentrations, hormones, and oxidative stress markers during the first five months (neonatal and peri-puberty age) in male Shiba goats.

Abstract

From a clinical point of view, the establishment of laboratory variables during the first few months of an animal’s life helps clinicians to make sure they base their medical decisions on laboratory values for the specific breed and age group. The present study aimed to investigate the monthly dynamics in some plasma elements, hematology, reproductive hormones, and oxidative stress marker profiles during the first five months of age (neonatal and peri-puberty stage) in male Shiba goat’s kids. Sixteen kids were investigated from the first to the fifth month (M1 to M5), and the data were presented as the statistical difference between them. Whole blood and plasma samples were collected monthly for analysis of basal hematology, plasma elements concentration (trace elements: Cu, Zn, Se, Fe, and Cr; macroelements: Ca and Mg), circulating hormones (cortisol, FSH, LH, IGF1, immunoreactive inhibin, testosterone, T3, and T4), and oxidative stress markers (MDA, CAT, SOD, and GPX). The results showed age-related changes in the observed parameters. The fifth month recorded the lowest level of almost all investigated minerals, except for Cr. Plasma hormone levels revealed age-dependent increases in IGF-1 and testosterone, age-related decreases in T3 and T4, and non-significant changes in cortisol and FSH. Besides, the concentrations of inhibin and LH were significantly higher at M1–M3 compared with M4–M5. Plasma SOD, GPX, and CAT were increased with age. In conclusion, age-related changes and a distinction of age in months was found necessary to interpret the laboratory results, specifically in terms of age in months and the peri-puberty stage in young goats, which are important to follow up the age-specific diseases, reproductive status, and treatment follow-ups in this stage.

Effects of Selenium as a Dietary Source on Performance, Inflammation, Cell Damage, and Reproduction of Livestock Induced by Heat Stress: A Review

Heat stress as a result of global warming has harmful consequences for livestock and is thus becoming an urgent issue for animal husbandry worldwide. Ruminants, growing pigs, and poultry are very susceptible to heat stress because of their fast growth, rapid metabolism, high production levels, and sensitivity to temperature. Heat stress compromises the efficiency of animal husbandry by affecting performance, gastrointestinal health, reproductive physiology, and causing cell damage. Selenium (Se) is an essential nutritional trace element for livestock production, which acts as a structural component in at least 25 selenoproteins (SELs); it is involved in thyroid hormone synthesis, and plays a key role in the antioxidant defense system. Dietary Se supplementation has been confirmed to support gastrointestinal health, production performance, and reproductive physiology under conditions of heat stress. The underlying mechanisms include the regulation of nutrient digestibility influenced by gastrointestinal microorganisms, antioxidant status, and immunocompetence. Moreover, heat stress damage to the gastrointestinal and mammary barrier is closely related to cell physiological functions, such as the fluidity and stability of cellular membranes, and the inhibition of receptors as well as transmembrane transport protein function. Se also plays an important role in inhibiting cell apoptosis and reducing cell inflammatory response induced by heat stress. This review highlights the progress of research regarding the dietary supplementation of Se in the mitigation of heat stress, addressing its mechanism and explaining the effect of Se on cell damage caused by heat stress, in order to provide a theoretical reference for the use of Se to mitigate heat stress in livestock.

Effect of Long-Acting Selenium Preparation on Health and Productivity of Sheep

The aim of this study was to determine the effects of long-acting selenium (Se) preparation in sheep. The experimental material comprised Skudda ewes and their lambs. The animals were divided into two equal groups: C-control, and E-experimental. Between days 70 and 80 of pregnancy, group E ewes were injected with Se preparation (Barium Selenate Injection, BVP Animal Care, Ireland) at f 1 mL/50 kg body weight. Hematological, biochemical and immunological blood parameters as well as Se levels were analyzed in ewes. The growth rate of lambs, the dimensions of the musculus longissimus dorsi (MLD) cross-section, and fat thickness over the loin-eye area were also determined. It was found that barium selenate stimulated the mechanisms of humoral and cellular immunity. The injection was an effective form of Se supply, which was confirmed by its increased concentration in the blood serum of lactating ewes. The offspring of the experimental ewes were characterized by a faster growth rate, and they achieved significantly higher body weight (p ≤ 0.05) at 100 days of age. The lambs also had significantly higher parameters of MLD (p ≤ 0.05) at similar carcass fat content.

Microbial reduction and resistance to selenium: Mechanisms, applications and prospects

Selenium is an essential trace element for humans, animals and microorganisms. Microbial transformations, in particular, selenium dissimilatory reduction and bioremediation applications have received increasing attention in recent years. This review focuses on multiple Se-reducing pathways under anaerobic and aerobic conditions, and the phylogenetic clustering of selenium reducing enzymes that are involved in these processes. It is emphasized that a selenium reductase may have more than one metabolic function, meanwhile, there are several Se(VI) and/or Se(IV) reduction pathways in a bacterial strain. It is noted that Se(IV)-reducing efficiency is inconsistent with Se(IV) resistance in bacteria. Moreover, we discussed the links of selenium transformations to biogeochemical cycling of other elements, roles of Se-reducing bacteria in soil, plant and digestion system, and the possibility of using functional genes involved in Se transformation as biomarker in different environments. In addition, we point out the gaps and perspectives both on Se transformation mechanisms and applications in terms of bioremediation, Se fortification or dietary supplementation.

Effects of Selenium Supplementation on Rumen Microbiota, Rumen Fermentation, and Apparent Nutrient Digestibility of Ruminant Animals: A Review

Enzymes excreted by rumen microbiome facilitate the conversion of ingested plant materials into major nutrients (e.g., volatile fatty acids (VFA) and microbial proteins) required for animal growth. Diet, animal age, and health affect the structure of the rumen microbial community. Pathogenic organisms in the rumen negatively affect fermentation processes in favor of energy loss and animal deprivation of nutrients in ingested feed. Drawing from the ban on antibiotic use during the last decade, the livestock industry has been focused on increasing rumen microbial nutrient supply to ruminants through the use of natural supplements that are capable of promoting the activity of beneficial rumen microflora. Selenium (Se) is a trace mineral commonly used as a supplement to regulate animal metabolism. However, a clear understanding of its effects on rumen microbial composition and rumen fermentation is not available. This review summarized the available literature for the effects of Se on specific rumen microorganisms along with consequences for rumen fermentation and digestibility. Some positive effects on total VFA, the molar proportion of propionate, acetate to propionate ratio, ruminal NH3-N, pH, enzymatic activity, ruminal microbiome composition, and digestibility were recorded. Because Se nanoparticles (SeNPs) were more effective than other forms of Se, more studies are needed to compare the effectiveness of synthetic SeNPs and lactic acid bacteria enriched with sodium selenite as a biological source of SeNPs and probiotics. Future studies also need to evaluate the effect of dietary Se on methane emissions.

Effect of Dietary Seaweed Supplementation in Cows on Milk Macrominerals, Trace Elements and Heavy Metal Concentrations

This study investigated the effect of seaweed supplementation in dairy cow diets on milk yield, basic composition, and mineral concentrations. Thirty-seven Icelandic cows were split into three diet treatments: control (CON, no seaweed), low seaweed (LSW, 0.75% concentrate dry matter (DM), 13–40 g/cow/day), and high seaweed (HSW, 1.5% concentrate DM, 26–158 g/cow/day). Cows were fed the same basal diet of grass silage and concentrate for a week, and then were introduced to the assigned experimental diets for 6 weeks. The seaweed mix of 91% Ascophyllum nodosum: 9% Laminaria digitata (DM basis), feed, and milk samples were collected weekly. Data were analyzed using a linear mixed effects model, with diet, week, and their interaction as fixed factors, cow ID as random factor, and the pre-treatment week data as a covariate. When compared with CON milk, LSW and HSW milk had, respectively, less Se (−1.4 and −3.1 μg/kg milk) and more I (+744 and +1649 μg/kg milk), while HSW milk also had less Cu (−11.6 μg/kg milk) and more As (+0.17 μg/kg milk) than CON milk. The minimal changes or concentrations in milk for Se, Cu, and As cannot be associated with any effects on consumer nutrition, but care should be taken when I-rich seaweed is fed to cows to avoid excessive animal I supply and milk I concentrations.

Supranutritional selenium level minimizes high concentrate diet-induced epithelial injury by alleviating oxidative stress and apoptosis in colon of goat

Background

High concentrate (HC) diet-induced oxidative stress causes gut epithelial damages associated with apoptosis. Selenium (Se) being an integral component of glutathione peroxidase (GSH-Px) plays an important role in antioxidant defense system. Therefore, increasing dietary Se level would alleviate HC diet-induced injuries in gut mucosa. The present study investigated eighteen cross-bred goats, randomly divided into three groups (n = 6/group) fed either low concentrate (LC, roughage: concentrate ratio 65:35), high concentrate (HC, 35:65) or HC plus Se (HC-SY) diets for 10 weeks. Se was supplemented at the dose rate of 0.5 mg Se kg^− 1 diet in the form of selenium yeast. The background Se level in HC and LC diets were 0.15 and 0.035 mg.kg^− 1 diet, respectively. The Se at the dose of 0.115 mg.kg^− 1 diet was added in LC diet to make its concentration equivalent to HC diet and with the supplementation of 0.5 mg Se kg^− 1, the goats in group HC-SY received total Se by 0.65 mg.kg^− 1 diet.

Results

The molar concentrations of individual and total short chain fatty acids (TSCFA) significantly increased (P < 0.05) with simultaneous decrease in pH of colonic fluid in goats of HC and HC-SY groups compared with LC goats. HC diet induced loss of epithelial integrity, inflammation and loss of goblet cells in colonic mucosa associated with higher lipopolysaccharide (LPS) concentrations in colonic fluid whereas, the addition of SY in HC diet alleviated such damaging changes. Compared with LC, the HC diet elevated malondialdehyde (MDA) level with concurrent decrease in GSH-Px and superoxide dismutase (SOD) activities, while SY supplementation attenuated these changes and improved antioxidant status in colonic epithelium. Moreover, epithelial injury and oxidative stress in colon of HC goats were associated with increased apoptosis as evidenced by downregulation of bcl2 and upregulation of bax, caspases 3 and 8 mRNA expressions compared with LC goats. On contrary, addition of SY in HC (HC-SY) diet alleviated these changes by modulating expression of apoptotic genes in colonic epithelium.

Conclusions

Our data suggest that supranutritional level of Se attenuates HC diet-induced oxidative stress and apoptosis and thereby minimizes the epithelial injury in colon of goats.

Comparison of Rumen Microbiota and Serum Biochemical Indices in White Cashmere Goats Fed Ensiled or Sun-Dried Mulberry Leaves

Mulberry leaves, which have high nutritional value, have not been fully utilized. Few research systems have indicated whether mulberry leaves can replace traditional feed ingredients in goats. In this study, we investigated the effects of feeding white cashmere goats ensiled (Group E) or sun-dried mulberry leaves (Group S) on changes in ruminal microbial communities, rumen fermentation parameters and serum biochemical indices. The control group (Group C) received a typical total mixed ration (TMR). 16S rRNA gene sequencing revealed 209 genera belonging to 19 bacterial phyla dominated by Firmicutes and Bacteroidetes. Only the relative abundances of Erysipelotrichaceae_UCG-009 were significantly different among the three groups (p < 0.05). Physiological and biochemical findings revealed that only the serum leptin concentrations were significantly decreased when mulberry leaves were added to the diets (p < 0.05). Correlation analysis revealed that Ruminococcus_2 were significantly positively correlated with the butyrate concentration. These findings suggested that supplementation with mulberry leaves only induced minor changes in the abovementioned indicators, implying that the rumen fermentation status was still stable after adding mulberry leaves to the diets.

Copper sulfate and sodium selenite lipid-microencapsulation modifies ruminal microbial fermentation in a dual-flow continuous-culture system

Undesirable interactions between trace mineral elements and ruminal contents may occur during digestion when mineral salts are supplemented. Antimicrobial effects of copper sulfate (CuSO₄) may affect ruminal digestibility of nutrients when fed as a source of copper (Cu), while sodium selenite (Na₂SeO₃) may be reduced in the rumen to less available forms of selenium (Se). Our objective was to evaluate if protection of CuSO₄ and Na₂SeO₃ by lipid-microencapsulation would induce changes on ruminal microbial fermentation. We used 8 fermentors in a dual-flow continuous-culture system in a 4 × 4 duplicated Latin square with a 2 × 2 factorial arrangement of treatments. Factors were CuSO₄ protection (unprotected and protected by lipid-microencapsulation) and Na₂SeO₃ protection (unprotected and protected by lipid-microencapsulation). Treatments consisted of supplementation with 15 mg/kg of Cu and 0.3 mg/kg of Se from either unprotected or protected (lipid-microencapsulated) sources, as follows: (1) Control (unprotected CuSO₄ + unprotected Na₂SeO₃); (2) Cu-P (protected CuSO₄ + unprotected Na₂SeO₃); (3) Se-P (unprotected CuSO₄ + protected Na₂SeO₃); (4) (Cu+Se)-P (protected CuSO₄ + protected Na₂SeO₃). All diets had the same nutrient composition and fermentors were fed 106 g of dry matter/d. Each experimental period was 10 d (7 d of adaptation and 3 d for sample collections). Daily pooled samples of effluents were analyzed for pH, NH₃-N, nutrient digestibility, and flows (g/d) of total N, NH₃-N, nonammonia N (NAN), bacterial N, dietary N, and bacterial efficiency. Kinetics of volatile fatty acids was analyzed in samples collected daily at 0, 1, 2, 4, 6, and 8 h after feeding. Main effects of Cu protection, Se protection, and their interaction were tested for all response variables. Kinetics data were analyzed as repeated measures. Protection of Cu decreased acetate molar proportion, increased butyrate proportion, and tended to decrease acetate:propionate ratio in samples of kinetics, but did not modify nutrient digestibility. Protection of Se tended to decrease NH₃-N concentration, NH₃-N flow, and CP digestibility; and to increase flows of nonammonia N and dietary N. Our results indicate that protection of CuSO₄ may increase butyrate concentration at expenses of acetate, while protection of Na₂SeO₃ tended to reduce ruminal degradation of N. Further research is needed to determine the effects of lipid-microencapsulation on intestinal absorption, tissue distribution of Cu and Se, and animal performance.

Effect of Slow-Release Pellets of Selenium and Iodine on Performance and Some Blood Metabolites of Pregnant Moghani Ewes and Their Lambs

The need for minerals during pregnancy in mammals increases by progress of gestation due to embryo development. Therefore, the supply of trace minerals for pregnant ewes in late pregnancy may be of vital importance. The present study was carried out to evaluate the effect of selenium and iodine release slowly on the performance and some blood parameters of pregnant ewes and their lambs. Experiments were performed on 40 pregnant ewes from 3 to 4 years old in the last month of pregnancy with a weighing average of 52 ± 5 kg and a factorial experiment (2 × 2) in a completely randomized design with 4 treatments and 10 replicates used for 120 days (30 days before and 90 days after parturition of ewes). Experimental treatments were containing the following: (1) control, (2) ewe receiving bolus containing iodine, (3) ewe receiving bolus containing iodine and selenium, and (4) ewe receiving bolus containing selenium. One month before the expected birth date, the pellets will be fed to each of the livestock by bolus gun. During the test period, ewes will not receive any other mineral supplements and will be kept in a group in a herd. Ewes were blood sampled at 10 days prepartum and 30 and 60 days postpartum. The results showed that body weight on birth and weaning of lambs and average daily gain of lambs were highest in bloused animals that were related to the slow-release selenium tablet lambs (P < 0.05). Lambs born to mothers receiving 0.3 mg day^-1 of selenium per day had a keratin phosphokinase concentration of T₄ concentration and T₄ to T₃ lower than that of zero selenium (P < 0.05). Daily gain, glutathione peroxidase activity, and T₄ concentration at iodine 0.4 mg day^-1 were significantly higher than iodine level (P < 0.05). The adding of slow- release pellets of iodine and selenium improved the immune system.

Effects of rumen bypass melatonin feeding (RBMF) on milk quality and mastitis of Holstein cows

Cow mastitis is a major problem frequently encountered by dairy farmers and it is manifested by the high number of somatic cells and the low quality of the milk. The conventional treatment for mastitis is use of antibiotics. In the current study, a new approach is applied to target this disorder: rumen bypass melatonin feeding (RBMF). The RBMF significantly reduced milk somatic cell count and improved milk nutritional values with the elevated protein, fat and dry matter levels. This approach also suppresses the stress and proinflammatory responses of the cows indicated by the reduced serum cortisol, TNF-α and IL-6 and increased IL-10 levels. Importantly, the beneficial effects of RBMF have lasted for several days after termination of the treatment. The effects of melatonin on the mastitis are probably attributed to the antioxidant and anti-inflammatory activities of melatonin. Considering the none or low toxicity of melatonin to organisms and the no invasive nature of this approach, we recommend that RBMF could be used in large scale in the dairy farming to target the cow mastitis.

Effects of rumen-protected folic acid and rumen-protected sodium selenite supplementation on lactation performance, nutrient digestion, ruminal fermentation and blood metabolites in dairy cows

BACKGROUND

Considering the insufficient ruminal synthesis of folic acid (FA), the higher degradability of FA, and the reduction of sodium selenite (SS) by ruminal microbes into non-absorbable elemental Se, this study evaluated the effects of rumen-protected FA (RPFA) and rumen-protected SS (RPSS) on lactation performance, nutrient digestion and blood metabolites in dairy cows.

RESULTS

Dry matter (DM) intake and milk composition were unaltered, milk and milk fat yields were higher for both supplements, and milk protein yield was higher for RPFA addition. Digestibility of DM, neutral detergent fibre and acid detergent fibre was higher for both supplements, whereas that of organic matter and crude protein was higher for RPFA addition. Ruminal pH and ammonia N were lower, and concentration of total volatile fatty acids was higher for both supplements. Activity of cellobiase and xylanase was higher for RPFA addition, whereas that of pectinase and protease was higher for both supplements. The populations of total ruminal fungi, protozoa, Ruminococcus flavefaciens and Butyrivibrio fibrisolvens were higher for both supplements. The RPFA × RPSS interaction was significant for α-amylase activity, total ruminal bacteria and R. albus populations; these three variables were increased by RPSS but the increase was greater when cows were also fed RPFA.

CONCLUSION

The results indicated that addition of RPFA or RPSS improved lactation performance, nutrient digestibility and ruminal fermentation in dairy cows by stimulating ruminal microbial growth and enzyme activity. © 2019 Society of Chemical Industry.

Revisiting Oxidative Stress and the Use of Organic Selenium in Dairy Cow Nutrition

In commercial animals production, productive stress can negatively impact health status and subsequent productive and reproductive performance. A great body of evidence has demonstrated that as a consequence of productive stress, an overproduction of free radicals, disturbance of redox balance/signaling, and oxidative stress were observed. There is a range of antioxidants that can be supplied with animal feed to help build and maintain the antioxidant defense system of the body responsible for prevention of the damaging effects of free radicals and the toxic products of their metabolism. Among feed-derived antioxidants, selenium (Se) was shown to have a special place as an essential part of 25 selenoproteins identified in animals. There is a comprehensive body of research in monogastric species that clearly shows that Se bioavailability within the diet is very much dependent on the form of the element used. Organic Se, in the form of selenomethionine (SeMet), has been reported to be a much more effective Se source when compared with mineral forms such as sodium selenite or selenate. It has been proposed that one of the main advantages of organic Se in pig and poultry nutrition is the non-specific incorporation of SeMet into general body proteins, thus forming an endogenous Se reserve that can be utilized during periods of stress for additional synthesis of selenoproteins. Responses in ruminant species to supplementary Se tend to be much more variable than those reported in monogastric species, and much of this variability may be a consequence of the different fates of Se forms in the rumen following ingestion. It is likely that the reducing conditions found in the rumen are responsible for the markedly lower assimilation of inorganic forms of Se, thus predisposing selenite-fed animals to potential Se inadequacy that may in turn compromise animal health and production. A growing body of evidence demonstrates that organic Se has a number of benefits, particularly in dairy and beef animals; these include improved Se and antioxidant status and better Se transfer via the placenta, colostrum, and milk to the newborn. However, there is a paucity in the data concerning molecular mechanisms of SeMet assimilation, metabolism and selenoprotein synthesis regulation in ruminant animals, and as such, further investigation is required.

Seleno-compounds and Carnosic Acid Added to Diets with Rapeseed and Fish Oils Affect Concentrations of Selected Elements and Chemical Composition in the Liver, Heart and Muscles of Lambs

The objective of our studies was to investigate effects of carnosic acid (CA), selenized yeast (SeY) and selenate (SeVI) added to the diet including rapeseed oil (RO) and fish oil (FO) on concentrations of elements, fatty acids (FAs), tocopherols, cholesterol, and malondialdehyde in the liver, heart, musculus longissimus dorsi (MLD), and musculus biceps femoris (MBF) of lambs. Lambs were fed diets: group I-the basal diet (BD) with RO; group II-BD with RO and FO; group III-BD with RO, FO, and CA; group IV-BD with RO, FO, CA, and SeY; group V-BD with RO, FO, CA, and SeVI. The diets with Se compounds increased Se concentrations in all tissues compared with other diets. The diet with SeVI increased Cd, Sb, and Pb concentrations in the liver compared to groups I, II, and IV. The diets containing Se compounds increased Sb and Pb concentrations in MBF compared to groups I and II. All diets with CA reduced As, Sb, and Pb concentrations in MLD compared to groups I and II. All diets with FO increased concentrations of FAs and malondialdehyde in the liver compared to group I. All diets with FO decreased FAs concentrations in MBF compared to group I. The diets containing CA with/without Se compounds increased malondialdehyde concentrations in MBF compared to groups I and II. The diet with Se compounds reduced malondialdehyde concentrations in MLD compared to group II. All diets with FO changed concentrations of tocopherols and cholesterol in all tissues compared to group I. Our study showed that the addition of SeY or SeVI to the experimental diet increased the concentration of Se in all assayed tissues of lambs without adversely influencing performance or causing physiological disorders in internal organs. Both, SeY or SeVI added to the experimental diet decreased the oxidative stress and the concentrations of As, Sb, and Pb in MLD compared with the diets containing RO, irrespective of the presence of FO (groups I and II). Our study provides useful knowledge for nutritionists carrying out further investigations aimed at improving farm animal health, performance, and the nutritional quality of animal products for humans.

Selenised yeast sources differ in their capacity to protect porcine jejunal epithelial cells from cadmium-induced toxicity and oxidised DNA damage

In recent years there has been increasing interest in the use of selenised yeast (Se-Y) as an antioxidant feed supplement. Here, three selenised yeast products are differentiated in terms of bioefficiency and the ameliorative effect on Cadmium (Cd) toxicity in porcine epithelial cells. A porcine digestion in vitro model was chosen to more accurately simulate the bioavailability of different Se-Y preparations, allowing a comprehensive understanding of the bio efficiency of each Se-Y compound in the porcine model. To elucidate a possible mechanism of action of selenium a number of bioassays were applied. Levels of Se dependent antioxidant enzymes (glutathione peroxidase and thioredoxin reductase) were evaluated to analyze the ROS neutralizing capacity of each Se-Y compound. The effects of Se-Y sources on Cd-induced DNA damage and apoptosis-associated DNA fragmentation was assessed using comet and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays, respectively. Lesion-specific DNA damage analysis and in vitro DNA repair assay determined the DNA repair capacity of each Se-Y source. The results presented in this study confirm that the ability of different commercially available Se-Y preparations to enhance a range of cellular mechanisms that protect porcine gut epithelial cells from Cd-induced damage is concentration-dependent and illustrates the difference in bioefficiency of different Se-Y compounds.

Invited review: Mineral absorption mechanisms, mineral interactions that affect acid-base and antioxidant status, and diet considerations to improve mineral status

Several minerals are required for life to exist. In animals, 7 elements (Ca, P, Mg, Na, K, Cl, and S) are required to be present in the diet in fairly large amounts (grams to tens of grams each day for the dairy cow) and are termed macrominerals. Several other elements are termed microminerals or trace minerals because they are required in much smaller amounts (milligrams to micrograms each day). In most cases the mineral in the diet must be absorbed across the gastrointestinal mucosa and enter the blood if it is to be of value to the animal. The bulk of this review discusses the paracellular and transcellular mechanisms used by the gastrointestinal tract to absorb each of the various minerals needed. Unfortunately, particularly in ruminants, interactions between minerals and other substances within the diet can occur within the digestive tract that impair mineral absorption. The attributes of organic or chelated minerals that might permit diet minerals to circumvent factors that inhibit absorption of more traditional inorganic forms of these minerals are discussed. Once absorbed, minerals are used in many ways. One focus of this review is the effect macrominerals have on the acid-base status of the animal. Manipulation of dietary cation and anion content is commonly used as a tool in the dry period and during lactation to improve performance. A section on how the strong ion theory can be used to understand these effects is included. Many microminerals play a role in the body as cofactors of enzymes involved in controlling free radicals within the body and are vital to antioxidant capabilities. Those same minerals, when consumed in excess, can become pro-oxidants in the body, generating destructive free radicals. Complex interactions between minerals can compromise the effectiveness of a diet in promoting health and productivity of the cow. The objective of this review is to provide insight into some of these mechanisms.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species-A Critical Review

Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.

Selenium Source Impacts Protection of Porcine Jejunal Epithelial Cells from Cadmium-Induced DNA Damage, with Maximum Protection Exhibited with Yeast-Derived Selenium Compounds

Selenium (Se) is found in inorganic and organic forms, both of which are commonly used in animal feed supplements. The aim of this study was to determine the impact of the chemical form of Se on its associated ameliorative effects on cadmium (Cd)-induced DNA damage in a porcine model. At a cellular level, Cd mediates free oxygen radical production leading in particular to DNA damage, with consequential mutagenesis and inhibition of DNA replication. In this study, porcine jejunal epithelial cells (IPEC-J2) were pre-incubated for 48 h with one of Se-yeast (Sel-Plex), selenomethionine (Se-M), sodium selenite (Se-Ni) or sodium selenate (Se-Na). The effects of this supplementation on cell viability and DNA damage following cadmium chloride (CdCl₂) exposure were subsequently evaluated. IPEC-J2 cells were cultivated throughout in medium supplemented with porcine serum to generate a superior model that recapitulated the porcine gut epithelium. The results illustrated that Se antioxidant effects were both composition- and dose-dependent as evident from cell viability (Alamar Blue and 5-carboxyfluorescein diacetate acetoxymethyl ester) and DNA damage assays (Comet and TUNEL). Both the Se-yeast and Se-M organic species, when used at the European Food Safety Authority guideline levels, had a protective effect against Cd-induced DNA damage in the IPEC-J2 model system whereas for inorganic Se-Ni and Se-Na sources no protective effects were observed and in fact these were shown to enhance the negative effects of Cd-induced DNA damage. It can be concluded that nutritional supplementation with organoselenium may protect porcine gut integrity from damage induced by Cd.

Selenium in Cattle: A Review

This review article examines the role of selenium (Se) and the effects of Se supplementation especially in the bovine species. Selenium is an important trace element in cattle. Some of its roles include the participation in the antioxidant defense the cattle farms. The nutritional requirements of Se in cattle are estimated at 100 μg/kg DM (dry matter) for beef cattle and at 300 μg/kg DM for dairy cows. The rations high in fermentable carbohydrates, nitrates, sulfates, calcium or hydrogen cyanide negatively influence the organism's use of the selenium contained in the diet. The Se supplementation may reduce the incidence of metritis and ovarian cysts during the postpartum period. The increase in fertility when adding Se is attributed to the reduction of the embryonic death during the first month of gestation. A use of organic Se in feed would provide a better transfer of Se in calves relative to mineral Se supplementation. The addition of Se yeasts in the foodstuffs of cows significantly increases the Se content and the percentage of polyunsaturated fatty acids (PUFA) in milk compared to the addition of sodium selenite. The enzyme 5-iodothyronine deiodinase is a seleno-dependent selenoprotein. It is one of the last proteins to be affected in the event of Se deficiency. This delay in response could explain the fact that several studies did not show the effect of Se supplementation on growth and weight gain of calves. Enrichment of Se in the diet did not significantly affect the slaughter weight and carcass yield of bulls. The impact and results of Se supplementation in cattle depend on physiological stage, Se status of animals, type and content of Se and types of Se administration. Further studies in Se supplementation should investigate the speciation of Se in food and yeasts, as well as understanding their metabolism and absorption. This constitute a path to exploit in order to explain certain different effects of Se.