Bakou et al. (Vol 3, N°3-4, 2005)

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Revue Africaine de Santé et de Productions Animales © 2005 E.I.S.M.V. de Dakar

A RTICLE ORIGINAL Histopathological alterations of bovine skeletal muscle observed at the slaughterhouse of Dakar (Senegal) S. BAKOU1*, Y. KANE2, B. MUSABYEMARIYA3, W. NDJOYI1, G. DAYO1, Mg. SEYDI3 1 2 3

EISMV - Service d’Anatomie-Histologie-Embryologie, BP 5077 Dakar-Fann, Sénégal EISMV - Service de Pathologie Médicale, Anatomie Pathologique et Clinique Ambulante, BP 5077 Dakar-Fann, Sénégal EISMV - Service d’Hygiène et Inspection des Denrées Animales et d’Origine Animales, BP 5077 Dakar-Fann, Sénégal

* Correspondance et tirés à part , e-mail : serakou2001@yahoo.fr

Abstract The aim of this study was to report the nature and incidence of muscular changes found upon histological examination at the time of slaughter in the slaughterhouse of Dakar (Senegal). Eighty cattle (Zebu and N’dama) coming from Senegal, Mali and Mauritania, and transported by trucks and train to the Slaughterhouse of Dakar (Senegal) were used in this study. Five muscles [Sternocephalicus (SC), Infraspinatus (IS), Pectoralis descendens (PD), Obturator (OB) et Diaphragma (DI)] were collected immediately after slaughter from each of the animals. Among these 400 samples processed for histology and examined in cross-sections, 10.5% exhibited isolated necrotic cells, 21.2% fibers splitting, and 60% hypercontracted fibers. Ten percent (10%) of samples showed a high incidence of hypercontracted fibers, 53.3% a medium incidence (less than de 10%) and 36.7% none. Hypercontraction was more frequent in DI muscles (P<0,05) (RASPA, 3 (3-4) : 164-168).

Keys – Words: Hypercontracted fibers - Skeletal muscle – Bovine - Meat quality - Senegal. Résumé Les altérations histopathologiques du muscle squelettique des bovins observées aux abattoirs de Dakar (Sénégal) Le but de cette étude était de rapporter la nature et l’incidence des altérations histopathologiques des muscles de bovins observées aux abattoirs de Dakar (Sénégal). Quatre-vingts bovins (Zébu et N’dama) provenant du Sénégal, du Mali et de la Mauritanie et acheminés par camions aux abattoirs de Dakar (Sénégal) ont été utilisés dans cette étude. Quelques minutes après l’abattage des animaux cinq muscles [sternocephalicus (SC), infraspinatus (IS), pectoralis descendens (PD), obturator internus (OI) et diaphragma (DI)] ont été prélevés, traités par les techniques histologiques et examinés. Sur les 400 échantillons musculaires examinés, 10,5% ont présenté des fibres nécrosées, 21,2% de fibres clivées et 60% de fibres hypercontractées. Dix pour cent (10%) des échantillons examinés ont présenté une forte incidence en fibres hypercontractées, 53,3% une incidence moyenne et 36,7% n’ont présenté aucune lésion. Le diaphragme est le muscle le plus atteint (71,4%, p<0,05).

Mots-clés : Fibres hypercontractées - Muscle squelettique - Bovin - Qualité de la viande - Sénégal.

Introduction The perception of meat quality depends on three criteria: tenderness, color and shelf life ability. Tenderness seems to be the most important sensory attribute of meat, affecting consumer acceptance of beef [14], [27]. Nevertheless, in developing countries like Senegal, the safety of food is the main concern for the average consumer. For instance, when he buys meat, he wants to be tasteful. But most of all, he requires that the product does not present any risk at an unacceptable level for his health, and for his life, that may be related to the presence of dangerous agents (micro-organisms, toxins, various contaminants)[19]. Thus, the quality of the meat is guaranteed by monitoring livestock health, and ante and post mortem inspection of animals. However, apart from the average consumer, in big cities like Abidjan, there is a new category of consumers concerned by the organoleptic quality of the beef meat as well. Technological, visual and organoleptic attributes of meat are influenced by genetic factors (species, sex, breed strain and genotype) and environmental factors (rearing, preslaughter handling and post slaughter management) [11]. RASPA Vol.3 N03-4, 2005

In numerous studies the significant influence of preslaughter handling on meat quality characteristics have been noted [16], [17]. Hypercontrated fibers (giant fibers) are known as a result of the stress of slaughtering [4], [22] and are incriminated in the default of technological and sensory qualities of meat. This type of muscle modification was observed in bovines [20], pigs [1], [9], [10], [12], [13], [21], turkeys [5], [15], [18], [22], [26], chickens [7] and Grasscutters [2]. The hypercontracted fibers are usually oval or round in shape and have a larger cross section than other the normal muscle fibers in most of the time. They can be found grouped or isolated and are generally located at the periphery of the muscle bundle. These muscle fibers have myofibrils excessively contracted with abnormally short sarcomeres [3]. These alterations of the muscle fibers are not identifiable by the current methods used during meat inspection in the slaughterhouses of Africa in general and Senegal in particular. The outcome is a misappreciation of this type of alteration. Therefore, the purpose of the present study

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