Análise das metodologias diretas e indiretas para a contagem de células somáticas no leite de cabras hígidas / Analysis of direct and indirect methods for somatic cell counts in the milk of healthy goats

RESUMO

A particularidade da secreção láctea caprina, do tipo apócrina, diferente da secreção merócrina da vaca, leva a erros de interpretação durante a realização de técnicas de avaliação da celularidade do leite de fêmeas desta espécie. Portanto, o presente trabalho teve o objetivo de determinar a contagem de células somáticas pelo método indireto California Mastitis Test (CMT), e por métodos diretos, incluindo a contagem por citometria de fluxo e a contagem microscópica direta, através da coloração de verde de metil e pironina-Y, além de comparar os métodos de contagem celular. Foram analisadas 102 amostras de 51 fêmeas caprinas, das raças Saanen, Parda Alpina e Toggenburg, criadas no Estado de São Paulo. Os animais foram categorizados segundo a fase da lactação, exame físico da glândula mamária e exame do leite. As amostras foram colhidas, após a realização do exame Califórnia Mastitis Test, em duas alíquotas, uma destinada à contagem celular automática e a outra, a contagem microscópica direta, utilizando-se o corante verde de metil e pironina- Y. De acordo com os diferentes escores do CMT, observou- se 74,5 por cento de amostras negativas, 8,8 por cento de amostras com escore traços, 8,8 por cento de amostras ligeiramente positivas (+), 6,8 por cento de amostras fracamente positivas (++) e 0,9 por cento de amostras fortemente positivas (+++). Os valores medianos das contagens de células somáticas presentes no leite de cabras, avaliadas através de contador automático e microscopia direta, e analisadas de acordo com os diferentes escores do CMT, foram, respectivamente, 181.000, 578.000, 628.000, 1.421.500 e 5.542.000 células/mL de leite e 74.991, 271.396, 71.420, 640.995 e 5.049.394 células/ mL de leite, nos escores negativo, traços, +, ++ e +++. Os valores medianos obtidos através da contagem de células somáticas pelo método automático e microscópico direto, de acordo com as fases de lactação foram de 159.500, 508.000 e 277.500 células/mL ...(AU)

ABSTRACT

The particular apocrine secretion of goat milk different from the merocrine one observed in cows, may lead to errors in interpreting cellularity evaluations in the milk of this species. Thus, the objective of the present trial was to determine Somatic Cell Counts by means of one indirect methods, the California Mastitis Test (CMT), and direct methods, flow cytometry and direct microscopic count using methyl green-pyronine-Y stain, beyond comparing the methods of cellular counting. A total of 102 samples from 51 Saanen, Brown Alpine and Toggenburg female goats, bred in the state of São Paulo, were analyzed. Goats were separated in groups according to the phase of lactation and to physical examination of the mammary gland, and milk examination. Samples were divided into two aliquots, and were collected after California Mastitis Test evaluation. One aliquot was used in automatic cell counts, and the other, in direct microscopic count using methyl green-pyronine-Y stain. CMT results were as follows 74.5 percent of the samples were negative, 8.8 percent yielded traces, 8.8 percent were weak positive (1), 6.8 percent were distinct positive (2) and 0.9 percent were strong positive (3). Medians of somatic cell counts in goat milk as evaluated by means automatic cell counter and direct microscopy, and grouped according to the different CMT scores, were as follows 181,000, 578,000, 628,000, 1,421,500, and 5,542,000 cells/mL of milk and 74,991, 271,396, 71,420, 640,995, and 5,049,394 cells/mL of milk in scores negative, traces, 1, 2 and 3, respectively. Medians obtained in automatic cell counts and direct microscopic counts, grouped according to the phase of lactation were 159,500; 508,000; and 277,500 cells/mL of milk and 62,493; 89,275; and 146,411 cells/ml of milk, respectively. The correlation between the automatic and microscopic methods for somatic cell counts was 88 percent. Based on the results obtained, it could be concluded that there ...(AU)