Seasonal changes of commercial traits, proximate and fatty acid compositions of the scallop Flexopecten glaber from the Mediterranean Sea (Southern Italy)

This study provides information on biological (gonadosomatic index), commercial quality (condition index and meat yield) and biochemical aspects (proximate composition, fatty acids) of the soft tissues of Flexopecten glaber reared in suspended cages in the Ionian Sea. The results showed that condition index (CI) and meat yield (MY) peaked in December (60 and 30%, respectively) and in April, May and June (from 53 to 60% for CI and from 34 to 36% for MY). Gonadosomatic index showed three main peaks in winter, spring and summer months. Contents of protein 8.18–11.9 g/100 g), lipid (0,.78–1.18 g/100 g) and carbohydrate (1.19–3.30 g/100 g) varied significantly during the study period. Saturated fatty acids was the dominant group, except in December when polyunsaturated fatty acids showed the highest proportion (43% of total FAs). Fatty acids of the n3 group were dominant with docosahexaenoic and eicosapentaenoic acids. Highest n3/n6 ratios were recorded in spring-summer specimens, with values > of 5. The results showed a better nutritional quality of scallops in May, July and December

Effects of Canola and Safflower Oil Supplementation in Diets, on Growth Performance and Fatty Acid Composition of Russian Sturgeon (Acipenser gueldenstaedtii Brandt, 1833)

The aim of this study was to determine the impact on growth performance and muscle fatty acid composition, of replacement of 50% fish oil (FO) with canola oil (CO) and safflower oil (SFO) in the diets of Russian sturgeon (Acipenser gueldenstaedtii). Two isoproteic (48%) and isolipidic (12%) diets were formulated combining two oil sources (50% fish oil + 50% canola oil or 50% fish oil + 50% safflower oil). The diets were fed to apparent satiation to triplicate groups for 15 weeks, twice a day. No significant differences were observed between the experimental groups fed CO and SFO diets in terms of weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio. The experimental groups fed CO and SFO diets did not show significant differences in terms of protein, lipid, ash, and moisture content in their muscle. There were no significant differences in muscle between total n-3 fatty acids but total n-6 fatty acids were significantly higher in SFO group (24.90%) than in CO group (21.30%). Total n-6 fatty acids were also higher than (20.43%) at the start. In conclusion, 50% replacement of FO by CO or SFO in Russian sturgeon diets had no negative effect on growth performance, feed efficiency and fatty acid composition in the muscle of this species