ENGLISH SUMMARY
       Sharpsnout sea bream is a promising specie to Spanish aquaculture, although, this fish is already in Italy, Greek and Cyprus markets among others. It has many advantages: It is omnivorous specie; it is easy to reproduce. Aquacultures’ farmers can use the same infrastructure used to produce other sparids. Nowadays,, it has a competitive market price.
       For all the reason mention above, this fish is potential specie for aquaculture production, although, there is not a specific meal for raising them. Right now, most of the aquaculturists use gilthead sea bream meal to feed them.  So the main objective of this Doctoral thesis is replace fish meal (FM) by sunflower meal (SFM) and pea protein concentrate (PPC) to raise sharpsnout sea bream fingerlings and juveniles. Other main objective is to partially substitute fish oil (FO) by soybean oil (SO) and pork fat (PF) to raise sharpsnout sea bream fingerlings and juveniles.
       Sharpsnout sea bream were fed with 0, 12, 24 and 35% of SFM. There was neither significant difference in fingerlings final fish growth nor in juveniles at the end of the experiments. At the same time, the amino acids profile and the efficiency of amino acids retention were not altered by SFM inclusion. It could consider until 35% SFM inclusion, sharpsnout sea bream could not affect either flesh quality or animal health for not longer than 160 days. At the end of fattening period, fish growth became slow, perhaps due to decreasing temperature or reproduction period. Similar behavior was observed in D. puntazzo fattening period but with lipid sources, at the same time of the year. 
       Pea protein meal inclusion affected sharpsnout sea bream final weight at the end of the pre – growth period, even with the minimum inclusion (16%). This growth reduction did not affect either amino acids profile or amino acid retention. Final growth was altered because of the presence of some anti–nutritional compounds that were thermo resistant. Another cause could be the deficient methionine supplementation in the experimental diets. Both alterations could cause some gut modification, like villous length elongation and goblet cells augmentation, to compensate nutrient miss absorption. 
       After these experiments, FO was partially replaced by SO and PL, 75% as a maximum substitution. In these diets 24% of SFM were included, according with the results obtained in previous experiments. There were no statistical differences in final fish growth at the end of the pre – growth experiment or “fingerling period”. Although, fatty acids profile of fish fillet was altered by alternative lipid sources, even with the minimum substitution in SO and PL. Nevertheless, these alterations were not so market, in PL diets. Apart, there was any histological alteration in fish liver, neither in fish fed SO diets nor in those who ate PL diets.
       In the growing experiment, FO was replaced by 50% SO and PL to prevent any adverse effects in liver histology or organoleptic alteration. At the end of the experiment, there was no significant difference in final growth. Although, FO substitution by SO or PL increased the FCR values. As it was expected, pork lard and soybean oil affected fatty acids profile, but again it was observed that sharpsnout sea bream showed a lower fatty acid profile alteration in fish fillet, when they were fed with 50% SO or PL diets. Through histology, it could be observed that liver of sharpsnout sea bream fed with FO and PL presented steatosis. Although, fatty acids were affected by lipid sources, it was observed through organoleptic test and trombogenicity and atherogenicity index that these fillets are healthy and not significant tasted alteration was detected by panelists. 
English Summary




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