An in-situ assessment of Dorsal Cranial Myopathy in broilers, approaching regarding meteorological influences in South Brazil, classification, and appearance of the lesions during industrial processing

Abstract

Broiler meat is a high-quality food for humans, and is worldwide consumed. Brazil plays an important role in the poultry industry and in its South region is situated the most important pro- ducer. Recently, alterations on the meat aspect have aroused the interest of researchers to clarify their causes. The objective of this investigation was to evaluate the relationship between environ- mental conditions and seasons on the prevalence of Dorsal Cranial Myopathy (DCM) and also, to generate a DCM classification in scores, for griller-type broilers. Carcasses were picked out from several stages of industrial processing from a slaughterhouse located in South Brazil. The preva- lence of DCM was measured using the database of partial condemnations of the Official Inspection Service during 19 months. Meteorological data were obtained from the National Institute of Meteo- rology (in Portuguese Instituto Nacional de Meteorologia- INMET), of the Ministry of Agriculture, Livestock and Supply. In addition, microorganisms with public health importance were measured on samples taken from the muscles with DCM. The prevalence of DCM was compared among sea- sons using Analysis of Variance (ANOVA). The relation with other environmental conditions was accessed using a principal component analysis. Partial condemnations by DCM were higher (P < 0.001) during autumn (0.529%) and winter (0.547%). In the other extreme, summer presented the lowest percentage of condemned carcass (0.199%). The prevalence of DCM appeared to be inversely related to the temperatures. The association between relative humidity and the prevalence of DCM seemed to move in the same direction. No differences were observed in the qualitative and quantitative microbiological analysis between carcasses affected by DCM and the control group (P > 0.05). Visually, it could be noted that the hemorrhagic lesion of the Anterior latissimus dorsi (ALD) muscle diminished during the processing line, making the DCM imperceptible, even in those carcasses with severe DCM score at the beginning of the process. In conclusion, the climate features approached here could be correlated to this emerging myopathy. However, this lesion does not represent a food security issue for the consumers regarding evaluated microorganisms, as this kind of lesion tends to disappear in the final sellable product.