Estatus de selenio en equinos Criollo-Chileno a pastoreo y su respuesta a la suplementación

RESUMEN Objetivo. Dos experimentos se realizaron para determinar el estatus de selenio en equinos Criollo-Chileno a pastoreo y, evaluar la respuesta a la suplementación con Na2SeO3. Materiales y métodos. Exp.1A caballos pertenecientes a 10 criaderos del sur de Chile se les determinó la actividad sanguínea de glutatión peroxidasa (GPx, EC.1.11.1.9) (AcGPx). Los animales pertenecieron a 3 grupos, pastoreo de otoño (PO, n=40), pastoreo de otoño y suplementados con avena (PO+A, n=47), y, pastoreo de primavera (PP, n=41). Exp2Se utilizaron equinos con carencia de selenio, distribuidos en tres grupos: G1, n=7, tratado con Na2SeO3 el día 0 (Se= 0.05 mg/kg pv, im); G2, n=8, suplementado con Na2SeO3, los días 0 y 15 y GC, n=8, control. La AcGPx se determinó al día 0, 30 y 120. Resultados. La mediana (Me) de la AcGPx en todos los grupos fue menor al límite adecuado (>130 U/gHb), mayor en PO+A (Me=92, P25%=47, P75%=129 U/gHb) y PP (Me=85, P25%=45, P75%=114 U/gHb) que en PO (Me=35, P25%=20, P75%=85 U/gHb) (p<0.05). En el experimento 2 la AcGPx fue similar y menor al adecuado en todos los grupos. La suplementación con Na2SeO3 aumentó (p<0.05) la AcGPx en G1 (121±52 U/gHb) y G2 (124±69 U/gHb), sin alcanzar valores adecuados. Conclusiones. Los equinos Criollo-Chileno a pastoreo en el sur de Chile presentan carencia de Se, mayor en otoño que primavera y menor al suplementar con avena. Adicionalmente, la administración parenteral de Na2SeO3 mejora el estatus de Se, pero sin revertir el cuadro carencial

Humoral and cellular immune response to Brucella abortus strain RB51 vaccine in grazing heifers supplemented with selenium and alpha-tocopherol

In order to evaluate the effect of selenium and alpha-tocopherol supplementation on the immune response to Brucella abortus strain RB51, four groups of six grazing heifers were used. Three months before the start of the trial, the groups Se-T and Se were supplemented in single dose with barium selenate (1 mg selenium/kg body weigth) and groups Se-T and T were supplemented with 500 IU alpha-tocopherol/100 kg each two months. Group C was maintained without supplementation. Once established differences in metabolic balance groups, the trial began with the RB51 vaccine administration. Blood samples with heparin and without additive were obtained from each cow for the determining blood activity of glutathione peroxidase (GPx) and plasma concentration of cholesterol and alpha-tocopherol. The humoral immune response was evaluated by ELISA and the cellular immune response by an intradermal test antigen of B. abortus. Differences between groups were evaluated by tests repeated measures ANOVA, paired samples t and Kruskal-Wallis. It was considered significant when the P value was less than 0.05. Supplementation with selenium and alpha-tocopherol established differences between groups (P < 0.05). The humoral immune response and cellular response to RB51 vaccine was lower in group T (P < 0.05). It is possible to conclude that humoral and cellular immune response to the vaccine RB51 can be negatively modulated by plasma alpha-tocopherol concentration at the immunization

Selenium metabolic status and response to supplementation in grazing Chilean-Criollo horses

Objective. Two experiments were conducted to determine the selenium status in grazing Chilean-Criollo horses and evaluate their response to a Na2SeO3 supplement. Material and methods. (Exp.1)The blood activity of glutathione peroxidase (GPx, EC.1.11.1.9) (AcGPx) was determined in horses kept grazing in 10 breeding farms from the south of Chile: PO, n = 40 horses were kept grazing during autumn (PO), 47 horses were kept grazing during autumn and supplemented with oat grain (PO + A), and 23 horses were kept grazing during spring (PP). (Exp.2)23 horses kept on pasture were allotted into three groups: G1, n = 7, supplemented with a dose of Na2SeO3 (Se = 0.05mg/kg bw, im) on day 0; G2, n = 8, supplemented with similar doses of Na2SeO3, on days 0 and 15; and GC, n = 8, control. AcGPx was determined on days 0, 30 and 120. Results. Median (Me) of the AcGPx on all the farms were below the adequate limit ( > 130 U/g Hb), being higher in PO + A (Me = 92, P-25% = 47, P-75% = 129 U/g Hb) and PP (Me = 85, P-25% = 45, P-75% = 114 U/g Hb) than PO (Me = 35, P-25% = 20, P-75% = 85 U/g Hb) (p < 0.05). Initial AcGPx was similar and below adequate in the three groups and increased after Na2SeO3 administration (p < 0.05) in G1 (121 +/- 52 U/g Hb) and G2 (124 +/- 69 U/g Hb). Conclusions. A deficiency is observed in Chilean-Criollo horses grazing during autumn and spring in southern Chile, parenteral administration of Na2SeO3 (0.05mg/kg bw) in single or double doses improves the Se status without achieving adequate values