Ioana Chirilean

Morpho-Histological Peculiarities of Oro-Pharyngeal Cavity of Rainbow Trout (Oncorhynchus mykiss, Wallbaum 1792)

To conduct life phenomena, living organism made materials and energy exchange with the environment. Essentially, standing of substance and energy needs is satisfied through processes of nutrition. The digestive system of fish have some peculiarities, both in terms of shape and the presence or absence of couple anatomical segments, depending on the species diet. Oro-pharyngeal cavity represents the first segment of the digestive tract in fish (Al Abdulhadi, 2005) and its structure contains multiple items: opening mouth, oral cavity, teeth, tongue and the pharynx (Stăncioiu, 2006). Other authors (Nicolae, 2007) consider teeth and tongue as constituent elements of oral cavity, and are not considered separate units of oro-pharyngeal cavity. Whatever of this classifications, most authors agree delimiting the oro-pharyngeal cavity, above the lips, and posterior by the last pair of gill arches (Bud, 2007). Rainbow trout (Oncorhynchus mykiss, Walbaum 1792) is one of the most exploited species of culture, both in Romania and worldwide. Several studies have been made on anatomical and histological structure of the various organs and body forming apparatus, but we consider they are insufficient. In this case, the authors of this paper aim to characterize in terms, morphological and histological, the first segment of digestive system, oro-pharyngeal cavity. These studies are made reasoned, for optimization of growth and nutrition technologies and increase the economic efficiency in aquaculture. For it, must be correlated several aspects of nutrition, ensure optimal environmental conditions, anatomic and histological structure of digestive tract and circulatory, respiratory and excretory systems.

Morphohistochemical studies of the bowel segments in the nutria.

A number of 10 nutria (Myocastor coypus) cadavers from private farms of Cluj; sacrificed as a necessity; were studied. Besides the morphological observations were also performed some histochemical; and histoenzymological observations at duodenum; jejunum - ileum and colon level; in order to emphasize so me indices concerning the cytoplasmatic basophily of e nterocites; RNA presence; absorption process; and a lso secretion product of caliciform cells.