Organic and inorganic selenium: IV. passive transfer of immunoglobulin from ewe to lamb

Effect of Prepartum Maternal Supplementation with Diphenyl Diselenide on Biochemical, Immunological, and Oxidative Parameters of the Offspring

This study aimed to assess the impact of prepartum maternal diphenyl diselenide (PhSe)2 supplementation on the development, biochemical, immune, and antioxidant parameters of calves. Eighteen Holstein breed calves were used, born to females who were or were not subjected to supplementation, at 42, 28, and 14 days prior to calving. The (PhSe)2 group (DDG) was administered 3 μmol/kg of (PhSe)2 in 4 mL of dimethyl sulfoxide (DMSO), while the DMSO and NaCl groups were administered 4 mL of DMSO and 0.9% NaCl, subcutaneously. The calves were evaluated based on their weight, withers height, body condition score 24 h post-birth (0), as well on days 14, 28, 42, 56, 70. Blood samples were also taken to determine serum variables. Calves on the DDG showed higher average levels of total protein, albumin, and globulins on day 0, and the immunoglobulin G level was significantly higher than the other groups on days 0, 14, 56, 70. Maternal supplementation showed immunomodulatory effect on calves, evidenced by the exceptional rates of passive immunity transfer, as well as the enhancement of humoral immunity. Our research offers fresh insights into the immunomodulatory potential of (PhSe)2, making it a viable alternative in facing this challenging phase, rearing dairy calves.

Metabolic profile of transition period in ewes and its influence on passive immunity transference in lambs

The intensification of ewe production, focusing on increasing prolificity, results in a higher incidence of metabolic disorders, especially in the transition period, which can lead to production losses with consequences for the health of the animals. The objective of this study was to evaluate the metabolic profile in transition period Lacaune ewes according to the parity and litter size born and its influence on the transference of passive immunity. Nineteen Lacaune ewes, with initial mean body weight of 76.36 ± 10.37 kg (SD), kept in a semi-extensive system and receiving the same diet, were used. Ewes were classified according to parity (primiparous and multiparous) and the litter size born at parturition (1, 2, and 3). On days - 14, - 7, and - 4 of the expected date of parturition and on days 1, 4, 7, and 14 days postpartum, blood sampling, the evaluation of the body condition score (BCS), and the weighing of animals were performed. Blood samples were taken from the lambs 48 h after birth. Colostrum was collected up to 6 h postpartum to determine the brix percentage. Serum concentrations of total plasma proteins (TPP), albumin, aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), paraoxonase (PON1), calcium (Ca), and magnesium (Mg) were evaluated. In lambs, the blood parameters evaluated were TPP, albumin, GGT, and PON1. Lamb plasma was used to estimate colostrum efficiency, brix percentage immunity, and total plasma protein (PPT). Productive data, pre- and postpartum metabolic variables for ewes, lambs, and those related to colostrum brix were analyzed. The BCS had a reduction (p < 0.0001) in the postpartum period, which is evidenced on days 7 and 14 (2.88 and 2.73, respectively). Serum concentration of BHB presented the highest concentrations in the prepartum period for ewes that gave birth to triplets, from day - 14, and for ewes that gave birth to twins on day - 4 (p = 0.0245). Serum concentration of NEFA demonstrated the highest value on day 14 in primiparous (1.07; p = 0.0402). Calcium had the lowest concentrations on day 1 (8.85 mg/dl, p < 0.0001) and magnesium on day 3 (1.79 mg/dl, p < 0.0001) postpartum. The multiparous with two lambs had higher brix percentages (30.5%), and the lowest value was observed in primiparous ewes that gave birth to a single lamb (27.06%; p = 0.0395). Triplet lambs had the lowest weight (3.73 kg, p = 0.0007), and the best brix percentage in plasma was observed in twins (10.29%, p = 0.0174). Regardless of the parity, the ewes that presented the greatest metabolic challenge were those that gave birth to triplets, and these lambs presented the worst immunity and the lowest live weight. The quality of colostrum was influenced by the parity, and multiparous ewes that gave birth to triplets had the lowest brix percentage in the colostrum.

Nano-selenium and Macleaya cordata Extracts Improved Immune Function and Reduced Oxidative Damage of Sows and IUGR Piglets After Heat Stress of Sows in Late Gestation

To investigate the effects of nano-selenium (nano-Se) and Macleaya cordata extracts (MCE) on immune function and oxidative damage of sows and intrauterine growth retardation (IUGR) piglets exposed to heat stress (HS) in large-scale farms, a 2 × 2 factorial design was adopted in this test, and the two factors were nano-Se (0, 0.50 mg/kg) and MCE (0, 500 mg/kg). A total of 80 sows ([Landrace × Yorkshire] × Duroc, parity 2) were used in a 25-day trial from day 90 of gestation to delivery with 20 replications per group and 1 sow per replication. The dietary treatments of sows were as follows: (1) CON group, basic diet (0.30 mg/kg added Se, sodium selenite); (2) Nano-Se group, basic diet (0.00 mg/kg added Se) + 0.50 mg/kg added nano-Se; (3) MCE group, basic diet (0.00 mg/kg added Se) + 500 mg/kg added MCE; and (4) Combined group, basic diet (0.00 mg/kg added Se) + 0.50 mg/kg added nano-Se and 500 mg/kg added MCE. The activities of serum SOD, CAT, and GSH-Px of sows and IUGR piglets were significantly increased in MCE group and combined group, and the MDA content was extremely decreased. There were extreme differences in serum IgG level of sows and IUGR piglets, colostrum, and serum IgM level of IUGR piglets in MCE group and combined group compared with CON group. Maternal combined diets increased greatly the levels of serum IL-10 and IFN-γ of sows and IUGR piglets, and decreased extremely the contents of serum IL-1β and TNF-α. MCE alone or combination with nano-Se in sow diets decreased greatly mRNA level of Hsp70 and increased mRNA level of Hsp27 in sows and IUGR piglets. In conclusion, nano-Se and/or MCE can be added to sow diets for the amelioration of HS-induced oxidative damage through improving immune function.

Trace minerals source in calf starters interacts with birth weights to affect growth performance

The present study was conducted to investigate the effects of partial replacement of inorganic minerals (IM) with trace minerals in advance chelate components form in starter diets for calves of different birth weights on performance, health, and behavior of Holstein calves. Fifty-two calves were assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement with two mineral sources (IM or advanced chelated minerals (ACMS)) and two birth weights (low or normal birth weight; LBW or NBW). Calves were weaned on d 56 and remained until d 71 of the study. Results showed that NBW calves had higher feed intake, withers and hip height, larger heart girth and lower fecal score than LBW calves throughout the study. Calves receiving ACMS tended to have higher feed intake, larger hip width, lower eye and nose scores, and lower rectal temperature throughout the study than IM calves. In addition, ACMS calves had larger abdominal girths at d 56 of the study compared to IM calves. Interactions between birth weights and mineral sources for preweaning average daily gain (ADG) and weaning and final BW showed that ACMS supplementation improved ADG and BW in LBW calves. Non-nutritive oral behavior was lower in ACMS calves compared to IM calves during all periods. Overall, ACMS feeding decreased non-nutritive oral behavior and improved calf health status during the study. In addition, feeding ACMS to dairy calves with LBW increased their ADG to a similar extent as to NBW calves, suggesting an improvement in their efficiency.

Essential and Toxic Mineral Content and Fatty Acid Profile of Colostrum in Dairy Sheep

Simple Summary

Colostrum is of interest to the scientific community because of its nutritional and therapeutic capabilities. The aims of this study were to characterize the macro and micro composition of colostrum from Sarda dairy sheep and to compare it with the composition of the mature milk of the same breed. The results of this survey showed a large variation in the immunoglobulin concentration in colostrum, which could affect the acquisition of passive immunity by lambs. The strong correlation between immunoglobulin G and the total protein content suggests that this can be used to estimate the immunoglobulin content in sheep colostrum. The concentration of essential minerals is higher in colostrum than in milk as a result of mineral salt block supplementation at the end of gestation. Colostrum has a significantly different fatty acid profile than milk, and this is due to the specific needs of newborn lambs.

Abstract

Colostrum is a major source of immunity in ruminants. It allows the transfer of antibodies from the mother to the fetus, and it is the exclusive source of nutrients for the newborn. The objectives of this study were (i) to characterize the macro and the micro composition of colostrum; (ii) to analyze the antioxidant capacity, fatty acid profile, and essential and toxic mineral content of colostrum; and (iii) to compare FA profiles and the amount of trace elements between colostrum and mature milk. For these purposes, samples of colostrum and milk were collected from a representative sample of animals from eight sheep dairy farms in the north of Sardinia (Italy). Fat, proteins, and seven essential and toxic minerals were measured in all samples of colostrum and milk. Furthermore, the FA profile was also measured in both matrices, while total antioxidant capacity was measured only in colostrum samples. The average amounts of fat and protein (TP) concentration in colostrum were 7.8% and 16%, respectively. Additionally, an average amount of 40 ± 20 g dm⁻³ was found for immunoglobulin G (IgG). As regards the antioxidant capacity of colostrum, a large variation was observed between samples from different farms for test 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), which was 30 ± 10% (mean ± standard deviation). High levels of selenium (Se), zinc (Zn), and copper (Cu) were found in colostrum (200 µg kg⁻¹, 25,000 µg kg⁻¹, and 1200 µg kg⁻¹, respectively). A strong positive correlation between TP and IgG was observed (r = 91%). In colostrum, the amount of IgG is positively correlated with Se and Zn, as they are essential minerals to the immune system. The FA profile demonstrated higher levels of medium and long chain fatty acids in colostrum than in mature milk, and this is mainly true for arachidonic acid (ARA), ecosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). This study provided new information on the quality of colostrum in Sarda dairy sheep and showed the different composition of fatty acids between colostrum and mature milk.

Nutritional strategies to alleviate oxidative stress in sows

The performance of high-yielding sows is directly related to the productivity of pig farming. Fetal development mainly occurs during the last month of pregnancy, and the aggressive metabolic burden of sows during this stage eventually leads to systemic oxidative stress. When affected by oxidative stress, sows exhibit adverse symptoms such as reduced feed intake, hindered fetal development, and even abortion. In addition, milk synthesis during the lactation period causes a severe metabolic burden. The biological response to oxidative stress during this period is associated with a decrease in milk production, which further affects the growth of piglets. Understanding the nutritional strategies to alleviate oxidative stress in sows is crucial to maintain their reproduction and lactation performance. Recently, advances have been made in the field of nutrition to relieve oxidative stress in sows during late pregnancy and lactation. This review highlights the nutritional strategies to relieve oxidative stress in sows reported within the last 20 years.

Effects of Selenomethionine on Cell Viability, Selenoprotein Expression and Antioxidant Function in Porcine Mammary Epithelial Cells

This study investigated the effects of selenomethionine (Se-Met) on the cell viability, selenoprotein expression, and antioxidant function of porcine mammary epithelial cells (pMECs) to reveal the underlying molecular mechanism of Se-Met on the lactation performance and antioxidant capacity of sows in vitro. The pMECs were used as an in vitro model and were treated with various concentrations of Se-Met (0, 0.5, 1, 2, and 4 μM). Cells were analyzed for cell viability, selenoprotein transcriptome, selenoprotein expression, and antioxidant enzyme activities. The results showed that, with increasing Se-Met concentrations, cell viability first increased and then decreased at 24, 48, or 72 h posttreatment with maximum values at 0.5-μM Se-Met. As the Se-Met concentrations increased, the mRNA expression of 17 selenoproteins first upregulated and then downregulated, with maximum values at 0.5-μM Se-Met. The 17 selenoproteins included SEPHS2, SELENOP, GPX1, GPX2, GPX3, GPX6, TXNRD1, SELENOK, SELENOW, DIO1, DIO2, DIO3, SELENOF, SELENOS, SELENOH, SELENOI, and SELENOT. Additionally, the protein expression levels of SEPHS2, SELENOP, GPX1, and TXNRD1 and the activities of glutathione peroxidase and thioredoxin were highest at 0.5-μM Se-Met. In conclusion, 0.5-μM Se-Met promotes cell viability partially by improving selenoprotein expression and antioxidant function in pMECs, which provides evidence for the potential ability of Se-Met to improve mammary gland health in sows.

Combined yeast culture and organic selenium supplementation during late gestation and lactation improve preweaning piglet performance by enhancing the antioxidant capacity and milk content in nutrient-restricted sows

This study was conducted to investigate the effects of dietary supplementation with yeast culture (YC) and organic selenium (Se) during late gestation and lactation on reproductive performance, milk quality, piglet preweaning performance, antioxidant capacity, and secretion of immunoglobulin in multiparous sows. A total of 160 healthy cross-bred sows (Landrace × Yorkshire, mean parity 4.1 ± 0.3) were randomly assigned to 4 groups as follows: 1) high nutrient (HN), 3,420 kcal/kg digestible energy (DE) and 18.0% crude protein (CP); 2) low nutrient (LN), 3,240 kcal/kg DE and 16.0% CP; 3) LN + YC, LN diet + 10 g/kg YC; 4) LN + YC + Se, LN diet + 10 g/kg YC + organic Se (1 mg/kg Se). Feeding trials of sows started from d 85 of pregnancy to d 35 of lactation. Compared with sows in the LN group, sows fed the LN + YC + Se diet had greater litter weaning weight, average litter gain, and milk fat content (14-d and 25-d milk) (P < 0.05). The content of malonaldehyde (MDA) (colostrum and 14-d milk) was lesser, and the activity of glutathione peroxidase (GSH-Px) (colostrum and 25-d milk) was greater when sows were fed the LN + YC + Se diet, compared with sows fed the LN diet (P < 0.05). Supplementation of YC and organic Se in the nutrient-restricted diet improved sows’ reproductive performance and pig weaning body weight by enhancing the antioxidant capacity and fat content in milk.

Maternal Selenium and Developmental Programming

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

Impact of Micronutrients on the Immune Response of Animals

Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most studies of micronutrient modulation of immune responses have been done in rodents and humans, thus limiting application to the health and well-being of livestock and companion animals. This exploratory review elucidates the role of vitamins and minerals on immune function and inflammatory responses in animals (pigs, dogs, cats, horses, goats, sheep, and cattle), with reference to rodents and humans.

Increasing selenium supply for heat-stressed or actively cooled sows improves piglet preweaning survival, colostrum and milk composition, as well as maternal selenium, antioxidant status and immunoglobulin transfer

This study aimed to evaluate the effects of increasing selenium (Se) supply for heat-stressed or actively cooled sows on sow productivity, colostrum and milk composition, as well as the selenium and antioxidant status and immunoglobulin levels of sows and nursing piglets. The study was a 2 × 2 factorial design, where the first factor was farrowing environment [heat stress vs. actively cooling, temperature: 29.61 ± 0.19 ℃ (27.70-31.60 ℃) vs. 27.90 ± 0.15 ℃ (26.90-30.20 ℃); temperature-humidity index: 72.91 ± 0.26 (70.30-75.70) vs. 70.81 ± 0.22 (69.30-73.80)], and the second factor was dietary Se level during late gestation and lactation [(0.3 vs. 1.2 mg/kg Se as Se-yeast, the basal diet was corn-soybean meal diet formulated according to NRC (2012) except for Se level]. Forty multiparous sows (Landrace × Yorkshire) were randomly allotted to 1 of 4 treatments (10 sows and following 90 piglets per treatment, respectively). The results show that: (1) There were no interactions of farrowing environment with Se treatments with the exceptions of nutrient content of 7-d milk; (2) As for zootechnical measures, piglets of sows receiving increasing Se tended to have greater preweaning survival compared with those of sows receiving control diet without interactions of environment and Se treatments; (3) As to colostrum and milk composition, greater concentrations of protein, lactose, solids-not-fat in colostrum, and greater fat concentration in 7-d and 14-d milk were found for sows fed increasing Se; (4) Regarding Se and antioxidant status, increasing Se supply for sows increased Se content in colostrum and 21-d milk, as well as in plasma of 1-day-old and 21-day-old piglets. Meanwhile, increasing Se supply for sows improved antioxidant status in colostrum (MDA content) and 21-d milk (T-AOC and MDA content), as well as in plasma of 1-day-old and 21-day-old piglets (GSH-Px activity and MDA content); (5) With regard to immunoglobulins, sows fed increasing Se had higher IgM levels in colostrum, and higher IgA in 21-d milk. Also, piglets from sows fed increasing Se had higher plasma IgA at 1 d of age, and higher IgA and IgG levels at 21 d of age. Collectively, increasing selenium supply for heat-stressed or actively cooled sows improved piglet preweaning survival, colostrum and milk composition, as well as maternal selenium, antioxidant status and immunoglobulin transfer irrespective of the climatic conditions, which indicates that Se requirements for sows should be urgently reassessed.

Effects of three methods of oral selenium-enriched yeast supplementation on blood components and growth in Holstein dairy calves

The objective of this study was to investigate the effect of three methods of oral selenium-enriched yeast (Se-yeast) supplementation on the blood characteristics and growth of Holstein dairy calves. The three methods were: (1) maternal (dams supplemented with 0.3 mg Se per kg of dietary DM during 3 weeks pre-calving), (2) post-calving (calf starter enriched with 0.3 mg Se per kg of DM), and (3) maternal and post-calving Se-yeast supplementation. These three methods were compared with a control group (no supplementation). Maternal supplementation with Se-yeast successfully increased Se concentration in the colostrum and the serum of calves 24 h after calving (P &lt; 0.05). At day 56, the Se concentration in the blood of calves supplemented with Se-yeast pre- (maternal) or post-calving (via starter) was greater than the control group (P &lt; 0.05), but maternal plus post-calving supplementation was not more effective than either maternal or post-calving supplementation. Globulin and total protein concentration in the blood of calves at day 0 increased and albumins:globulins decreased with maternal supplementation (P &lt; 0.05), but these variables were similar for all treatments at day 56. Immunoglobulins in the blood of calves and colostrum were not affected by maternal Se-yeast supplementation. Maternal supplementation increased the concentration of urea in the blood of calves at 0 days (P &lt; 0.05), but not at 56 days. Calf birthweight was increased with maternal supplementation of Se-yeast (P &lt; 0.01), but growth to day 56 was not affected by the methods of Se supplementation. Maternal supplementation with Se-yeast may improve growth and health characteristics of calves at calving time.

Effects of feeding pregnant beef cows selenium-enriched alfalfa hay on selenium status and antibody titers in their newborn calves

In newborn dairy calves, it has been demonstrated that supranutritional maternal and colostral Se supplementation using Se yeast or sodium selenite, respectively, improves passive transfer of IgG. In beef cattle, agronomic biofortification with Se is a more practical alternative for Se supplementation, whereby the Se concentration of hay is increased through the use of Se-containing fertilizer amendments. It has been previously demonstrated that agronomic Se biofortification is an effective strategy to improve immunity and performance in Se-replete weaned beef calves. The objective of this experiment was to determine the effects of feeding beef cows Se-enriched alfalfa (Medicago sativa) hay during the last 8 to 12 wk of gestation on passive transfer of antibodies to calves. At 10 wk ± 16 d before calving, 45 cows were assigned to 1 of 3 treatment groups with 3 pens (5 cows/pen) per treatment: Control cows were fed non-Se-fortified alfalfa hay plus a mineral supplement containing 120 mg/kg Se from sodium selenite, Med-Se cows were fed alfalfa hay fertilized with 45.0 g Se/ha as sodium selenate, and High-Se cows were fed alfalfa hay fertilized with 89.9 g Se/ha as sodium selenate; both the Med-Se and the High-Se groups received mineral supplement without added Se. Colostrum and whole blood (WB) were collected from cows at calving, and WB was collected from calves within 2 h of calving and at 12, 24, 36, and 48 h of age. Concentrations of IgG1 and J-5 Escherichia coli antibody in cow colostrum and calf serum were quantified using ELISA procedures. Selenium concentrations linearly increased in WB (P < 0.001) and colostrum (P < 0.001) of cows and in WB of newborn calves (P < 0.001) with increasing Se concentration in alfalfa hay. Colostrum concentrations of IgG1 (P = 0.03) were increased in cows fed Se-biofortified alfalfa hay, but J-5 E. coli antibody (P = 0.43) concentrations were not. Calf serum IgG1 (P = 0.43) and J-5 E. coli antibody (P = 0.44) concentrations during the first 48 h of age were not affected by prior Se treatment of cows. These data suggest that feeding Se-biofortified alfalfa hay promotes the accumulation of Se and antibodies in colostrum but does not affect short-term serum antibody concentrations in calves.

Supplementation of Merino ewes with vitamin E plus selenium increases α-tocopherol and selenium concentrations in plasma of the lamb but does not improve their immune function

Vitamin E and selenium have been reported to improve immune function across a range of species. Ewes lambing on poor-quality dry pasture in autumn in Western Australia are at risk of being deficient in vitamin E and selenium at lambing thus predisposing their lambs to deficiencies and increasing the risk of infection and disease. This study tested the hypotheses that (i) supplementation of autumn-lambing ewes with vitamin E plus selenium in late gestation will increase the concentrations of vitamin E and selenium in plasma in the ewe and lamb and (ii) that the increased concentrations of vitamin E and selenium in plasma in the lambs will improve their innate and adaptive immune responses and thus survival. Pregnant Merino ewes were divided into a control group (n=58) which received no supplementation or a group supplemented with vitamin E plus selenium (n=55). On days 111, 125 and 140 of pregnancy ewes in the vitamin E plus selenium group were given 4 g all-rac-α-tocopherol acetate orally. On day 111 the ewes were also given 60 mg of selenium as barium selenate by subcutaneous injection. The concentrations of α-tocopherol and selenium were measured in ewes and/or lambs from day 111 of pregnancy to 14 weeks of age±10 days (weaning). Immune function of the lamb was assessed by analysing the numbers and phagocytic capacities of monocytes and polymorphonuclear leucocytes and plasma IgG and anti-tetanus toxoid antibody concentrations between birth and 14 weeks of age±10 days. Maternal supplementation with vitamin E plus selenium increased the concentration of α-tocopherol in plasma (1.13 v. 0.67 mg/l; P<0.001) and selenium in whole blood (0.12 v. 0.07 mg/l; P<0.01) of the ewes at lambing compared with controls. Supplementation also increased the concentration of α-tocopherol (0.14 v. 0.08 mg/l; P<0.001) and selenium (0.08 v. 0.05 mg/l; P<0.01) in lambs at birth compared with controls. There was no significant effect of supplementation on immune function or survival in the lambs.

Functionality and genomics of selenium and vitamin E supplementation in ruminants

Selenium (Se) and vitamin E are essential micronutrients for animal health and production. The major function of both Se and vitamin E is to prevent the oxidative damage of biological membranes and they can influence growth, reproduction, immune function, health, and product quality in ruminants. Both Se and vitamin E are important for maintaining low cellular and systemic concentrations of reactive oxygen species and lipid hydroperoxides, to ensure optimum cellular function. Discovery of various selenoproteins and vitamin E-responsive genes has contributed significantly to improving our understanding about multiple functions of Se and vitamin E. There is evidence that these functions extend beyond the classical antioxidant properties to immunomodulation and intracellular cell signalling and gene regulation. Research in recent years has also shown that supranutritional supplementation of Se and vitamin E is required to improve the performance of ruminants under certain stressful conditions such as heat stress and during transition period. Considering the growing awareness among consumers of the benefits of antioxidant-rich food, there is a great opportunity for the livestock industries to focus on producing antioxidant-enriched milk and meat products or functional foods. The present review focuses on the recent developments in understanding multiple functions of Se and vitamin E at the cellular and molecular level and the effects of supranutritional supplementation on ruminant performance. In addition, the paper also articulates the potential opportunities to produce functional foods enriched with antioxidants, and underlines the need for optimum supplementation of these micronutrients for efficient ruminant production.

The case for pre-parturient selenium and iodine supplementation of ewes for improving lamb survival

Lamb survival is an issue of high relevance to the Australian sheep industry, as lamb-survival rates have direct bearing on overall reproductive performance of the sheep, and also constitute a main concern from an animal welfare perspective (Mellor and Stafford 2004). Both genetic and management factors play an important role in this complex issue (Hinch and Brien 2014). Ewe nutrition is of particular relevance as the intrauterine growth conditions prepare the lamb for the crucial transition to life outside the uterus. Effects of body condition of the ewe during various stages of the pregnancy have been investigated in detail, yet much less is known about the critical role of micronutrient provision to the ewe. Although several risk factors for selenium (Se) and iodine (I) subclinical deficiencies exist for sheep on pasture in Australia, determining micronutrient status in sheep or pasture is not straightforward. Several studies have separately found effects of Se and I supplementation on lamb survival. Studies investigating the interaction of Se and I supplementation have been few but results have demonstrated an interaction between Se and I. With increased twinning rates as a result of increased selection of numbers of lambs weaned, nutritional demands during pregnancy across flocks are increasing, and effects of micronutrients on lamb health and survival have greater impact. New opportunities in nutritional research are encouraging new studies into the effects of Se and I supplementation on lamb survival.

Physiological changes in the peri-partum period and colostral IgG transfer in prolific D'man sheep: effects of parity and litter size

The aim of this work was to assess maternal and neonatal changes in plasma proteins, glucose and cortisol and to quantify the colostral immunoglobulin G (IgG) transfer in the peri-partum period in D'man sheep, a prolific breed, taking into account the parity of the ewe. The concentrations of proteins and glucose were high in the ewes on day 7 and at lambing before decreasing. Likewise, cortisol plasma concentration was maximal during the 6 h following lambing and dropped at 12 h. Protein and glucose concentrations were low in lambs at 1 h of birth after which they increased. By contrast, cortisol level was the highest during the first 12 h of birth and then decreased. The colostral IgG level was high at lambing and dropped by over 87 % from 1 to 48 h post-partum. In the newborn, the plasma IgG concentration was lowest at birth and increased rapidly during the first 24 h of birth. Parity influenced maternal physiology with multiparous ewes having the lowest concentrations of proteins, glucose, IgG and cortisol, but the highest colostrum IgG level. Accordingly, lambs born from primiparous ewes had lower protein, glucose and plasma IgG concentrations than lambs born from multiparous ewes. The main outcome of this study was that lambs born from primiparous ewes are characterized by the lowest physiological indices and this may influence their survival chance.

Effect of selenium yeast supplementation on naturally acquired parasitic infection in ewes

Gastrointestinal parasites cause substantial economic losses in pasture-based sheep production systems. Supranutritional organic selenium (Se) supplementation may be beneficial because it improves immune responses to pathogens. To evaluate the effect of Se-yeast supplementation on gastrointestinal parasite load, 30 ewes per treatment group were drenched weekly with no Se, 4.9 mg Se/week as Se yeast (maximum FDA-allowed concentration), or supranutritional concentrations of Se yeast (14.7 and 24.5 mg Se/week) starting early fall for 85 weeks. Fecal samples were collected at weeks 63, 66, 78, and 84 and counted for total trichostrongyle-type eggs and Haemonchus contortus eggs (in samples with ≥200 trichostrongyle eggs/g feces). During breeding season (fall), ewes were kept on pasture; ewes receiving 24.5 mg Se/week had lower fecal trichostrongyle egg counts (93 ± 40 eggs/g feces) compared with ewes receiving no Se (537 ± 257 eggs/g feces; P = 0.007) or ewes receiving 4.9 mg Se/week as Se yeast (398 ± 208 eggs/g feces; P = 0.03). In winter, fecal trichostrongyle egg counts decreased, and group differences were not apparent. During lambing season (spring), ewes were kept in the barn and fecal trichostrongyle egg counts increased, although no group differences were observed. However, none of the ewes receiving supranutritional Se yeast, and with trichostrongyle egg counts ≥200 eggs/g of feces, but four of the ewes receiving lower Se dosages had H. contortus egg counts ≥1,000 eggs/g feces (P = 0.04). Our results suggest that supranutritional Se-yeast supplementation may enhance resistance to naturally occurring H. contortus gastrointestinal parasitism in sheep.

Effect of supranutritional maternal and colostral selenium supplementation on passive absorption of immunoglobulin G in selenium-replete dairy calves

Selenium (Se) is an essential micronutrient for ruminant animals affecting both performance and immune functions. Adding 3 mg of Se/L (in the form of Na selenite) to colostrum has been shown to improve IgG absorption in Se-deficient newborn dairy calves. The objective of our study was to determine the effect of supranutritional maternal and colostral Se supplementation on IgG status of Se-replete dairy calves. The study design was a 2 × 2 × 2 factorial design. During the last 8 wk before calving, dairy cows at a commercial dairy were fed either 0 (control cows) or 105 mg of Se-yeast once weekly (supranutritional Se-yeast-supplemented cows), in addition to Na selenite at 0.3 mg of Se/kg of DM in their ration. After birth, calves were fed pooled colostrum from control or supranutritional Se-yeast-supplemented cows to which 0 or 3 mg of Se/L (in the form of Na selenite) was added. Concentrations of whole-blood (WB) Se and serum Se measured at birth and at 48 h and 14 d of age, and serum IgG concentrations measured at 48 h and 14 and 60 d of age were determined. Calves born to Se-yeast-supplemented cows had higher WB-Se and serum-Se concentrations for the first 2 wk, and higher IgG absorption efficiency (62% at 48 h), resulting in higher serum-IgG concentrations (43% at 48 h and 65% at 14 d) and higher total serum-IgG content (50% at 48 h and 75% at 14 d), compared with calves born to control cows. Calves that received colostrum with added Na selenite had higher WB-Se concentrations for the first 2 wk, but only at 14 d of age were serum-Se concentrations, serum-IgG concentrations (53% higher), and total serum-IgG content (56% higher) higher, compared with calves that were fed colostrum without added Na selenite. Calves born to Se-yeast-supplemented cows that received colostrum from Se-yeast cows without added Na selenite had a higher IgG absorption efficiency compared with all other treatment groups. Our results support that feeding cows supranutritional Se-yeast supplement during the dry period or spiking colostrum with Na selenite both improve IgG status of Se-replete calves.

Antioxidant dynamics in the live animal and implications for ruminant health and product (meat/milk) quality: role of vitamin E and selenium

The global population is predicted to grow to over 9 billion by the middle of 21st century, with 70% of people living in urban areas, and food demand is projected to grow by 70% by 2050. Climate change presents a series of challenges for global animal agriculture. As a result of thermal challenges associated with climate variability, availability of quality pasture, animal behaviour, physiological and immunological functions are potentially impacted. Oxidative status plays an important role in the regulation and maintenance of several physiological and immunological functions of the body. Ruminants are exposed to several environmental and metabolic challenges that can trigger oxidative stress. In this scenario, it is possible for an increase in free radical production and a depletion of antioxidant reserves, resulting in damage to lipids, proteins and DNA. Since oxidative stress can affect animal health and the quality of their products (meat/milk), antioxidant supplementation of ruminant diets represents a useful tool to sustain redox homeostasis when the ruminants are exposed to oxidative stress. This paper will examine the roles that oxidative stress plays in some physiological functions, and it will discuss the implications of antioxidant supplementation on ruminant health and production. Physiological levels of dietary antioxidants underpin efficient energy utilisation, optimal antioxidant potential, and balanced mitochondrial function to enhance protein deposition without impacting animal health. The research conducted over the last decade has improved the understanding of physiological functions of antioxidants, with selenium and vitamin E receiving particular attention. There is evidence that the functions of selenium and vitamin E extend beyond the classical antioxidant properties to immunomodulation especially when administered at higher doses than recommended. Improving the oxidative status of ruminants will play an important role in delivering high-quality milk and meat products to consumers. Considering the growing awareness among consumers of the benefits of antioxidant-rich food, there is a great opportunity for the livestock industries to focus on producing antioxidant-enriched milk and meat products or functional foods. Therefore, the premise of this paper is to review the recent developments in understanding antioxidant dynamics in ruminants and their role in reducing the impact of environmental stress and metabolic diseases. In addition, the paper will explore the putative implications that antioxidant supplementation has on the quality animal products and how the improved understanding can be best utilised to achieve efficient and sustainable animal production systems to ensure quality animal products for human consumption.

Selenium supplementation restores innate and humoral immune responses in footrot-affected sheep

Dietary selenium (Se) alters whole-blood Se concentrations in sheep, dependent upon Se source and dosage administered, but little is known about effects on immune function. We used footrot (FR) as a disease model to test the effects of supranutritional Se supplementation on immune function. To determine the effect of Se-source (organic Se-yeast, inorganic Na-selenite or Na-selenate) and Se-dosage (1, 3, 5 times FDA-permitted level) on FR severity, 120 ewes with and 120 ewes without FR were drenched weekly for 62 weeks with different Se sources and dosages (30 ewes/treatment group). Innate immunity was evaluated after 62 weeks of supplementation by measuring neutrophil bacterial killing ability. Adaptive immune function was evaluated by immunizing sheep with keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. At baseline, FR-affected ewes had lower whole-blood and serum-Se concentrations; this difference was not observed after Se supplementation. Se supplementation increased neutrophil bacterial killing percentages in FR-affected sheep to percentages observed in supplemented and non-supplemented healthy sheep. Similarly, Se supplementation increased KLH antibody titers in FR-affected sheep to titers observed in healthy sheep. FR-affected sheep demonstrated suppressed cell-mediated immunity at 24 hours after intradermal KLH challenge, although there was no improvement with Se supplementation. We did not consistently prevent nor improve recovery from FR over the 62 week Se-treatment period. In conclusion, Se supplementation does not prevent FR, but does restore innate and humoral immune functions negatively affected by FR.

Effects of feeding selenium-enriched alfalfa hay on immunity and health of weaned beef calves

Previously, we reported that feeding selenium (Se)-enriched forage improves antibody titers in mature beef cows, and whole-blood Se concentrations and growth rates in weaned beef calves. Our current objective was to test whether beef calves fed Se-enriched alfalfa hay during the transition period between weaning and movement to a feedlot also have improved immune responses and slaughter weights. Recently weaned beef calves (n = 60) were fed an alfalfa-hay-based diet for 7 weeks, which was harvested from fields fertilized with sodium selenate at 0, 22.5, 45.0, or 89.9 g Se/ha. All calves were immunized with J-5 Escherichia coli bacterin. Serum was collected for antibody titers 2 weeks after the third immunization. Whole-blood neutrophils collected at 6 or 7 weeks were evaluated for total antioxidant potential, bacterial killing activity, and expression of genes associated with selenoproteins and innate immunity. Calves fed the highest versus the lowest level of Se-enriched alfalfa hay had higher antibody titers (P = 0.02), thioredoxin reductase-2 mRNA levels (P = 0.07), and a greater neutrophil total antioxidant potential (P = 0.10), whereas mRNA levels of interleukin-8 receptor (P = 0.02), L-selectin (P = 0.07), and thioredoxin reductase-1 (P = 0.07) were lower. In the feedlot, calves previously fed the highest-Se forage had lower mortality (P = 0.04) and greater slaughter weights (P = 0.02). Our results suggest that, in areas with low-forage Se concentrations, feeding beef calves Se-enriched alfalfa hay during the weaning transition period improves vaccination responses and subsequent growth and survival in the feedlot.

Effects of inorganic or organic selenium on immunoglobulins in swine

A study was conducted to determine if Se source fed during gestation and lactation affects passive transfer of immunoglobulins. Sixty days prior to breeding (d -60), gilts were randomly assigned to one of three treatments prior to breeding and throughout gestation: control (Control, no supplemental Se; n = 8), inorganic Se (Inorganic Se, 0.3 ppm; n = 4) and organic Se (Organic Se, 0.3 ppm; n = 4). Blood was collected on d -60, 57 and 113 of gestation and on d 21 of lactation and milk was collected at d 0, 1, 7, 14, and 21 of lactation. Blood was collected from piglets at d 0, 1, 7, 14, and 21 of age. Gilts fed organic Se had greater (P < 0.05) circulating concentrations of Se than Inorganic and Control gilts. Regardless of treatment, circulating concentrations of Se were greatest (P < 0.05) at d -60 compared to all other days. Serum concentrations of IgG were greatest (P < 0.05) in gilts at d 57 of gestation compared to d 113. Serum concentrations of IgA were greatest (P < 0.05) on d 113 of gestation and d 21 of lactation compared to d -60 and 57. Serum concentrations of IgM were greater (P < 0.05) at d 57 compared to d -60. Inorganic gilts had greater (P < 0.05) colostral and milk concentrations of IgG and IgM than Organic or Control gilts. Circulating concentrations of Se in piglets were greatest (P < 0.05) at d 14 and 21 of age compared to all other days. Piglets from gilts supplemented with organic Se had greater (P < 0.05) circulating concentrations of Se on d 1 versus piglets from gilts supplemented with no additional Se. The immunoglobulin concentrations of IgG, IgA, and IgM were lowest (P < 0.05) on d 0 and then increased when compared to d 1. The addition of different sources of Se did not affect the immunoglobulin concentrations in the gilt or piglet.

Selenium supplementation alters gene expression profiles associated with innate immunity in whole-blood neutrophils of sheep

Footrot (FR) is a common, contagious bacterial disease of sheep that results in lameness and significant economic losses for producers. We previously reported that sheep affected with FR have lower whole-blood (WB) selenium (Se) concentrations and that Se supplementation in conjunction with routine control practices accelerates recovery from FR. To determine whether oral Se-yeast administered at supranutritional levels (>4.9 mg Se/week) alters the ability of sheep to resist or recover from FR infection, 60 ewes with and 60 ewes without FR were drenched once weekly for 62.5 weeks with 0, 4.9, 14.7, or 24.5 mg organic Se-yeast (30 ewes per treatment group). Footrot prevalence and severity were measured at 0, 20, 28, 40, and 60 weeks of Se supplementation. Genomic expression of eight WB-neutrophil genes for selenoproteins and seven WB-neutrophil genes for proteins involved in innate immunity was determined at the end of the treatment period using SYBR Green and quantitative polymerase chain reaction methodology. Supranutritional Se-yeast supplementation successfully increased Se status in sheep but did not prevent FR. Supranutritional Se-yeast supplementation increased WB-neutrophil expression of genes involved in innate immunity: L-selectin, interleukin-8 receptor, and toll-like receptor 4, which were or tended to be lower in ewes affected with FR. Furthermore, supranutritional Se-yeast supplementation altered the expression of selenoprotein genes involved in innate immunity, increasing selenoprotein S and glutathione peroxidase 4 and decreasing iodothyronine deiodinases 2 and 3. In conclusion, supranutritional Se-yeast supplementation does not prevent FR, but does alter WB-neutrophil gene expression profiles associated with innate immunity, including reversing those impacted by FR.