Replacement of fish meal by a mixture of vegetal proteins and vegetal proteins combined with prebiotics in Gilt-head sea bream diets (Sparus aurata)

Eed Saad Desouky, Hesham
Jover Cerdá, Miguel (dir.)

Universidad de Zaragoza, VET, 2015

Máster Universitario en Nutrición Animal

Resumen: Three diets have been formulated to evaluate the effect of prebiotec (dry hydrolyzed intestinal mucosa) by supplementation in plant protein diets of gilt-head sea bream of 273g (average initial weight) for 60 days. The diets manufactured to be isonitrogenous (47% crude Protein, CP) and isolipidic (17% crude Lipid, CL) , two diets of them with total replacement of fish meal by a mixture of vegetable proteins, with and without prebiotec 0% Fish meal FM0 & 0% fish meal plus prebiotec FM0 + P. The third diet as the unique protein source 100% fish meal FM100. The growth, nutritional, biometric and histological parameters have been determined at the end of trial, fish reached weights 284, 303 and 407g in the FM0, FM0+P, and FM100 respectively. A statistical differences were observed between FM100 and other two (FM0 & FM0+P) diets in specific growth rate (SGR), Daily feeding rate (DFR), feed conversion ratio (FCR) and protein efficiency ratio (PER). Biometric indices show significant differences between FM100 and other two (FM0 & FM0+P) in condition factor (CF), viscerosomatic index (VSI), hepatosomatic index (HSI) and meat index (MI) as they were significantly decreasing by increasing FM replacement percent, also there were significant differences between FM100 and FM0 in Headless index (HI). The index of the non-edible parts (NEPI) was significantly higher in (FM0 & FM100) than FM100 while there were no significant differences between all diets in mesenteric fat index (MFI). Moreover, body composition was affected by the substitution with vegetable proteins, there was a decrease in water, protein and ash content and an increase of lipid and energy content from the start to the end of the trial. At the end of trial fat content was higher in the gilt-head sea bream fed FM100 diet followed by FM0+P and the least amount of fat was in gilt-head sea bream fed with feed FM0 when there were no significant differences in energy content in all groups. Protein and ash content also presents significant differences between the gilt-head sea bream that fed with feed FM0 and the gilt-head sea bream that fed other diets (FM0+P, FM100) where they were higher in FM0. The histological parameters of gut and liver not affected by different experimental diets. The morphological evaluation showed all fish in intermediate case except in FM0+P there was a severe fat accumulation within the hepatocytes. . The supplementation of prebiotec (dry hydrolyzed intestinal mucosa) was not useful contrary to the results of Tortosa, (2004) may be result to the parasite infections during the trial. The results of the current study showed that the immune role of the prebiotec was not enough to face the parasite infection and it is not recommended to use as a supplementation in vegetable meals in case of presence of parasites risk.

Tipo de Trabajo Académico: Trabajo Fin de Master