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Identifier

000380704

Title

Επίδραση της διατροφής στη φυσιολογία του εντέρου και την ανοσολογική κατάσταση της τσιπούρας Sparus aurata. Παράγωγα σόγιας και αντιδιατροφικοί της παράγοντες

Alternative Title

The effect of nutrition on intestinal physiology and immune status of gilthead sea bream Sparus aurata. Soy products and antinutritional factors

Author

Κοκού, Φωτεινή

Thesis advisor

Κεντούρη, Μαρουδιώ

Reviewer

Αλέξη, Μ
Ρήγος, Γ.

Abstract

Fish meal supplies the largest portion of dietary protein of carnivorous fish in aquaculture. Alternative protein sources have been studied intensively during the last few decades because of the declining availability and high cost of fish meal. Soybean meal is one of the most interesting alternatives to fish meal for diets of carnivorous fish, as it has high protein content, high availability and a competitive price. Its nutritive value to fish is, however, compromised by the presence of anti-nutritional factors, such as saponins and phytoestrogens, and the high levels of indigestible carbohydrates, such as non-starch polysaccharides, which may have detrimental effects on growth. These components are also known to affect digestive physiology, reduce the digestibility and utilization of the nutrients, as well as affect immune function and gut integrity of fish. Diverse feed processing techniques such as bioprocessing, alcohol extraction or enzyme treatment can reduce the final content of these factors and minimize their negative impacts. The main object of this doctorate thesis is to study the overall effects of feeding gilthead sea bream with diets containing different processed soybean meal products with reduced levels of antinutrients, as well as with diets containing pure soybean anti-nutritional factors. The addition of exogenous digestive enzymes in feeds for sea bream was also tested as a means for improving growth performance and feed utilization. The results are evaluated taking into account growth performance, gut integrity and liver structure, immune status as well as oxidative and intestinal enzyme activity. The main outcomes of the study revealed a potent inclusion of processed soybean products in feeds for sea bream up to a level of 40% substitution of fish meal, without affecting negatively fish performance. Pure antinutrients in the diets did not affect growth performance significantly, but affected digestive function, gut integrity and health status of fish. Addition of exogenous enzymes in feeds for sea bream indicated improved performance at high levels of soybean meal inclusion in the diets.

Language

Greek

Subject

Digestibility

Digestive enzymes

Histology

Immune system

Oxidative stress

Ανάπτυξη

Ανοσοποιητικό σύστημα

Ιστολογία

Οξειδωτικό στρες