In calves, neonatal mortality and disease susceptibility are greatly influenced by failure in passive immunization, normally provided by colostrum ingestion just after birth. Formulations projected to replace natural colostrum have not been successful, and one of the possible reasons for such failure is that orally administered Ig are probably digested in the gastrointestinal tract, so they are not absorbed as intact functional molecules. With the aim of finding an adequate colostrum substitute, we used columns of immobilized jacalin, a lectin known by its ability to bind O-linked oligosaccharides, to obtain a colostral Ig population putatively protected against enzymatic cleavage by the presence of sugar chains. Immunoglobulin G1 is a major constituent of colostrum Ig bound to jacalin (JB-Ig). This preparation contains 10% of the total colostral Ig and is typically 3 to 6 times more resistant to pepsin digestion than the Ig contained in the fraction that is not bound to jacalin, which presumably does not contain O-glycans. Mass spectrometry analysis demonstrated that the tryptic peptides obtained from JB-Ig and unbound Ig were similar, indicating that their distinct susceptibility to enzyme hydrolysis was associated with differences in their sugar chains. Therefore, the present research suggests that the bovine colostrum JB-Ig has potential application in the immunotherapy of neonatal calves that have not been supplied with colostrum.

The hematopoietic system changes during the pregnancy to carry fetal development and maternal needs. This study compared the hematological parameters between ewes with single and twin pregnancies during gestation, delivery, and postpartum. The experiment was conducted on 60 healthy pregnant Dorper ewes that were divided into two experimental groups: Group 1 (G1), with single pregnancies (n=30), and Group 2 (G2), with twin pregnancies (n=30). Blood samples were collected from all ewes at different times: immediately before fixed-time artificial insemination (AI); on day 30, 90, 120, 130, and 140 of pregnancy; immediately after delivery; and at 24h and 48h postpartum. Statistical analysis compared the two groups at different times (P<0.05). Mild, normocytic, and hypochromic anemia was detected in all ewes from AI time and throughout pregnancy from both groups, but did not prove to be of clinical relevance. In the peripartum stage (from the 140th day of pregnancy to 48h postpartum), the ewes with twin pregnancies (G2) exhibited higher erythrogram values and neutrophil:lymphocyte ratio than did ewes with single pregnancies (G1). This indicated a greater hematopoietic adaptation in the body during the development of two fetuses. Except for the eosinophil numbers, all leukogram parameters were influenced by pregnancy in a similar way in both groups, and was characterized mainly by leukocytosis with neutrophilia during peripartum due to the high presence of endogenous cortisol at delivery. Thus, these findings showed that pregnancy was a stressful physiological event that increased the leukocyte count with a slight alteration in the erythrogram of Dorper ewes.

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ResumoO presente trabalho visou verificar a eficiência da dosagem de lisozima como indicador de imunidade em bovinos, valendo-se de animais naturalmente acometidos de processo diarréico. Para tanto, foram utilizados bezerros com até três meses de idade, criados em manejo semi-intensivo e divididos em três grupos experimentais (I -sem diarréia, II -com diarréia mas sem sintomas sistêmicos, III -com diarréia e sintomas sistêmicos). Foram colhidas amostras sangüíneas de cada animal, que foram processadas para a realização da dosagem de gamaglobulinas por eletroforese, dosagem de IgG por imunodifusão radial, contagem de linfócitos e dosagem de lisozima. Os resultados encontrados mostraram existir linfopenia nos animais do grupo III, mas não foi verificada hipogamaglobulinemia na eletroforese ou na imunodifusão radial. Não foram encontradas diferenças estatisticamente significantes no nível de lisozima entre os grupos estudados. Não foi possível demonstrar correlação entre a dosagem de lisozima e os outros indicadores preconizados no presente experimento. Todavia, embora no presente experimento não se tenha encontrado uma correlação positiva entre o teor de lisozima e parâmetros de resposta imunitária, os resultados obtidos sugerem que novos trabalhos devam ser realizados para que tal parâmetro seja validado como indicador biológico.Palavras-chave: lisozima, resposta imune, bezerros. AbstractThe purpose of this work was to evaluate the serum lysozyme concentration as an indicator of immune response in bovine, considering naturally affected animals with diarrheic process. The experiment was conducted using 3 months old calves, raised in semi-intensive system and allocated into 3 groups with 10 animals each one (I -no diarrhea, II -diarrhea but no systemic symptoms, III -diarrhea and systemic symptoms). Blood samples were collected from each animal and processed by electrophoresis to verify the gamma-globulin content. The IgG was measured by radial immunodiffusion. Other measurements included blood lymphocyte count and serum lysozyme concentration. The results showed lymphopenia in animals of group III, but no differences were found in gamma-globulin content, as measured by electrophoresis and radial immunodiffusion. No differences were found in the lysozyme content in all groups analyzed and it was not possible to demonstrate a correlation between the lysozime content and the other indicators studied in this experiment. However, although it was not found this positive correlation, the results suggest that new works have to be performed to validate this parameter as a biological indicator.

O objetivo deste trabalho foi avaliar o efeito de diferentes doses de ciclofosfamida como indutor de imunossupressão experimental em ovinos. Foram empregados 30 animais, divididos em quatro grupos experimentais. Os animais dos grupos I, II e III foram submetidos, respectivamente, às doses de 10, 25 e 40mg kg-1 e os do grupo IV não receberam a droga, permanecendo como controle. Todos os animais foram imunizados com vacina contra a brucelose e, seis dias após a vacinação, foi feita a titulação através da soroaglutinação rápida em placa. Foi feita também a contagem de linfócitos sangüíneos e a dosagem de gamaglobulinas séricas, diariamente, durante uma semana, após a aplicação da ciclofosfamida. Houve óbitos apenas em alguns animais do grupo III (40mg kg-1). Assim, a droga mostrou-se segura com doses inferiores a 25mg kg-1. Quanto à imunossupressão, a mesma pôde ser demonstrada tanto nos animais que receberam 25mg kg-1, quanto aqueles que receberam 40mg/kg, através da análise dos resultados das contagens de linfócitos e dos títulos pós-vacinais anti-brucela. A dose de 25mg kg-1 de ciclofosfamida mostrou-se, assim, a mais adequada para ser usada em modelos de imunodepressão em ovinos, considerando sua ação imunossupressora e sua segurança e toxicidade.