Pesquisa Veterinária Brasileira (May 2010)
Efeito de medicamentos indicados para a prevenção da mastite bovina no período seco sobre a função fagocítica in vitro de leucócitos do leite de caprinos Effect of dry cow therapy products on the in vitro phagocytic function of goat milk leukocytes
Abstract
O uso de medicamentos antimamíticos específicos para vacas no período seco é indicado para prevenção de infecções na lactação seguinte. Não obstante, a ação das células envolvidas no período de secagem tem fundamental importância para a involução da glândula mamária e seu restabelecimento para a lactação subseqüente. A indisponibilidade de tais medicamentos para uso em cabras tem resultado na extrapolação do uso de produtos recomendados para vacas sem que se considerem as particularidades e diferenças anátomo-fisiológicas entre as espécies bovina e caprina. O presente estudo teve por objetivo avaliar a influência de cinco antimamíticos específicos para vacas secas sobre a função dos fagócitos provenientes de leite caprino. Para tal, fez-se o isolamento de células somáticas de 20 amostras de leite provenientes de 10 cabras lactantes, sem antecedentes de tratamento de mamite nos últimos 30 dias, sob condições higiênico-sanitárias de colheita e com resultados negativos ao cultivo microbiológico do leite. As células aderidas a lamínulas de vidro foram confrontadas com formulações contendo princípios ativos disponíveis no mercado como Gentamicina (M1), Cefalônio Anidro (M2), Ampicilina (M3), Cloxacilina Benzatínica (M4) e Cefapirina Benzatínica (M5). Avaliou-se, por microscopia, a fagocitose de partículas de Zymosan. As médias dos índices de fagocitose das células submetidas ao tratamento com M2 (15,12% ± 16,22), M3 (6,02% ± 7,96), M4 (4,54% ± 5,45) e M5 (2,47% ± 4,64) foram menores (pThe use of specific anti-mastitis drugs is indicated in dry cow therapy to prevent infections in the following lactation. Nonetheless, cells active in the dry period are of fundamental importance for the involution of the mammary gland and its recovery for the following lactation. Since there are no specific drugs for dry goat therapy, the dry cow therapy drugs tend to be misused in goats despite of the anatomical and physiological differences apart from the particularities of the two species. The objective of the present study was to evaluate the influence of five drugs specific for dry cow therapy on the function of goat milk phagocytes. Somatic cells were isolated from 20 milk samples of 10 lactating goats that had not been treated for mastitis during the previous 30 days. Milk samples were collected properly and microbiological culture yielded negative results. Cells adherent to glass coverslips were treated with commercially available dry cow therapy drugs containing active principles such as Gentamicin (M1), Cephalonium anhydrous (M2), Ampicillin (M3), Cloxacillin benzathine (M4) and Cephapirin benzathine (M5). Phagocytosis of Zymosan particles was evaluated. Mean phagocytosis indexes of cells treated with M2 (15.12% ± 16.22), M3 (6.02% ± 7.96), M4 (4.54% ± 5.45) and M5 (2.47% ± 4.64) were lower (p<0.001) than mean phagocytosis index of the control group (40.67% ± 19.68). Mean phagocytosis index of cells treated with M2 was greater (p<0.05) than those treated with M3, M4 and M5, whereas means of the latter three treatments were statistically similar. M1-treated cells did not adhere adequately to the cover slips, making it impossible to evaluate phagocytosis in this group. The results obtained enable the conclusion that drugs used affected milk phagocytes negatively. However, interference on somatic cell function is not the sole factor determining an unsuccessful dry period therapy, since the efficacy of the active principle on pathogens responsible for infectious processes also has to be considered.
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