Document Type : Review paper
The rapid expansion of aquaculture in many parts of the world has supported vigorous research programmers on nutrition and the feeding of cultivated aquatic organisms. Teleosts, as an important source of food supply for human, have successfully adapted themselves to every type of aquatic habitat. This versatility is reflected in their mode of feeding. The digestive tract of fishes shows a remarkable diversity of morphological and functional characteristics. This is related to different feeding habits and to taxonomy, as well as to body shape and weight, size and sex. The morphology of post- gastric alimentary canal has also been studied from many species of fish because knowledge of fish's alimentary canal morphology is becoming increasingly important in fish digestive physiology and improvement of nutrition protocols. Identification of digestive tract structure is essential for understanding the related histophysiological mechanisms and nutritional functions. This knowledge may help identify differences in microscopic anatomy of alimentary canal among various teleost species. Fish intestine plays a vital role in digestion and absorption of dietary nutrients. The anatomical and histological characteristics of fish intestine are expected to be helpful for understanding the related functional mechanisms and feeding habits, which can further be helpful for diagnosing some intestinal diseases and formulating suitable feeds. The histological characteristics of fish intestine can be affected by abiotic and biotic factors. In present review, the morphological features of teleostean fish's intestine have been discussed in many species to provide the best available information on intestinal structure and morphology.