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.

Serum concentration of thyroxine and triiodothyronine in newborn calves from cows supplemented with barium selenate / Concentración sérica de tiroxina y triiodotironina en terneros recién nacidos de madres suplementadas con selenato de bario / Concentração de tiroxina e triiodotironina sérica em bezerros recém-nascidos de mães suplementadas com selenato de bário

Abstract Background: Barium selenate is an inorganic source of selenium (Se) used in prolonged-release preparations to treat selenium deficiency in bovines. Objective: To evaluate serum concentrations of triiodothyronine (T3) and thyroxine (T4) hormones in newborn calves from mothers supplemented with barium selenate during prepartum. Methods: Six black Frisian pregnant cows were supplemented with barium selenate subcutaneously during the last two months of gestation, until calving. Six cows were used as controls. All cows were subjected to a low Se diet, consisting of hay from natural pasture and commercial concentrate lacking Se. The Se balance was measured through the activity of erythrocyte glutathione peroxidase (GPx). Serum concentration of T3 and T4 in calves was determined by electrochemiluminescence. Results: Se supplementation during prepartum increased GPx activity in cows from day 45 post-supplementation (p<0.05). Calves from supplemented mothers showed higher average serum Se concentration than calves from non-supplemented mothers. The average concentration of T3 in the calves from supplemented mothers was lower in the first hour of life (p<0.05) compared with calves from mothers of the non-supplemented group. A decrease (p<0.05) in T4 serum concentrations was observed in both groups at seven days of age. Conclusions: Administration of barium selenate to cows during prepartum generates a reduction in serum concentration of T3 in the first hour of life of calves.

Resumen Antecedentes: El selenato de bario es una fuente inorgánica de selenio (Se) utilizada en preparaciones de liberación prolongada para corregir el estado de carencia de Se en bovinos. Objetivo: Evaluar las concentraciones séricas de triyodotironina (T3) y tiroxina (T4) en terneros recién nacidos de madres suplementadas durante el preparto con selenato de bario. Métodos: Seis vacas frisón negro con 7 meses de gestación fueron suplementadas vía subcutánea con selenato de bario dos meses previos a la fecha de parto. Otras seis vacas permanecieron como controles. Todas las vacas se mantuvieron con una dieta cuyo aporte de Se fue inferior a los requerimientos y consistió en heno de pradera natural y concentrado comercial sin Se. El balance de Se se midió usando la actividad eritrocitaria de glutatión peroxidasa (GPx) y las concentraciones de T3 y T4 en terneros mediante electroquimioluminiscencia. Resultados: La suplementación con Se aumentó la actividad de GPx en vacas desde el día 45 post suplementación (p<0,05). Los terneros de madres suplementadas mostraron una concentración sérica promedio de Se mayor que los terneros de madres no suplementadas. La concentración promedio de T3 de terneros de madres suplementadas fue menor en la primera hora de vida (p<0,05) que en terneros de madres no suplementadas. A los 7 días de edad hubo una disminución (p<0,05) en las concentraciones séricas de T4 en ambos grupos. Conclusión: La administración de selenato de bario en vacas preparto genera una disminución en la concentración sérica de T3 en la primera hora de vida del ternero.

Resumo Antecedentes: O selenato de bário é uma fonte inorgânica de selênio (Se) usada em preparações de liberação prolongada para corrigir o status de deficiência de Se em bovinos. Objetivo: Avaliar as concentrações séricas de triiodotironina (T3) e tiroxina (T4) em bezerros recém-nascidos de mães suplementadas durante o pré-parto com selenato de bário. Métodos: Seis vacas friesianas negras aos 7 meses de gestação foram suplementadas com selenato de bário por via subcutânea dois meses antes do parto. Seis outras vacas permaneceram como controle. Todas as vacas foram mantidas em uma dieta cuja contribuição de Se foi inferior aos requeridos e consistiram em feno natural da pradaria e concentrado comercial sem Se. O balanço de Se foi medido usando a atividade eritrocitária das concentrações de glutationa peroxidase (GPx) e T3 e T4 em bezerros por eletroquimiluminescência. Resultados: A suplementação com atividade de GPx aumentou em vacas a partir do dia 45 após a suplementação (p<0,05). Os bezerros de mães suplementadas apresentaram uma concentração sérica média de Se maior que os bezerros de mães não suplementadas. A concentração média de T3 dos bezerros das mães suplementadas foi menor na primeira hora de vida (p<0,05) do que nos bezerros das mães não suplementadas. Aos 7 dias de idade houve uma diminuição (p<0,05) nas concentrações séricas de T4 nos dois grupos. Conclusão: A administração de selenato de bário em vacas de parto gera uma diminuição na concentração sérica de T3 na primeira hora de vida do bezerro.

The Efficacy of a Long-Acting Injectable Selenium Preparation Administered to Pregnant Ewes and Lambs.

The aim of this study was to evaluate the effects of a long-acting selenium (Se) preparation administered to sheep. The experiment was conducted on 30 dams and 36 lambs divided into three equal groups of 10 dams and 12 lambs each: Control-C, and two experimental groups-E (Se administered to pregnant ewes) and EI (Se administered directly to lambs after the colostral period). The Se preparation (Barium Selenate Injection, BVP Animal Care, 50 mg/mL) was administered by injection at 1 mL/50 kg (1 mg Se/kg) body weight (BW) to group E ewes in the third month of pregnancy (between 70 and 90 days) and to group EI lambs between 4 and 7 days of age. The following parameters were determined: Se concentration in the blood of ewes, milk yield, milk composition, Se concentration in milk; hematological, biochemical, and immunological parameters and Se concentration in the blood of lambs; growth rate and in vivo measurements of lean meat and fat content in lambs. Barium selenate significantly improved the Se status of dams and lambs, regardless of whether it was administered to pregnant ewes or directly to lambs in the first week of their life. The milk of ewes receiving the Se preparation was characterized by higher concentrations of fat and dry matter. The Se preparation induced significant changes in immunological parameters, thus enhancing defense mechanisms in lambs. The Se preparation exerted more stimulatory effects on humoral and cellular immune responses when administered directly to lambs after the colostral period (group EI) than to pregnant ewes (group E). The results of this study indicate that the long-acting Se preparation delivers benefits to sheep by boosting their immunity and, therefore, improving performance.

Selenomethionine as a Safer Substitute for Barium Selenate in Long-Acting Injectable Se Supplements for Food-Producing Animals.

Nutritional supplementation with selenium (Se) can prevent Se deficiency in food-producing animals. Injection with slow-release formulations is a preferred method for free-range grazing sheep and cattle, and barium selenate (BaSeO4) provides optimal efficacy. This chemical can become a health risk to humans if the concentrated depot of an injection site is consumed, and consequently such use is recently banned in the EU. A possible replacement is selenomethionine (SeMet), a naturally occurring form of Se supplementation hitherto only administered orally. In four animal studies we found that injection with SeMet maintained nutritionally adequate concentrations of Se in blood and tissues of lambs for at least 191 days and in blood and milk of dairy cows for at least 95 days. Stereoisomer forms L- and DL-SeMet were functionally equivalent. This is the first demonstration that injectable SeMet can deliver efficacy similar to BaSeO4 but with less risk of undesirable residues in edible tissues.