The present study was undertaken in order to determine the effect of a dietary incorporation of soy bean meal (SBM, trypsin inhibitor activity 1.6 mg/g) on growth performance, nutrient utilization and gut histology of Egyptian sole Solea aegyptiaca. This species, which is genetically and morphologically close to Solea solea, is currently present in the Mediterranean Sea and reared in some Italian farms, using the same techniques for Solea solea production and it could represent a promising new species for Mediterranean aquaculture. Three isoproteic and isolipidic extruded diets (crude protein, 47%, crude fat, 20%) were formulated containing 0 (diet 1), 18 (diet 2) and 30% SBM (diet 3). 540 juveniles (initial body weight of 6.9±0.2g) were equally distributed into nine 150 litres squared tanks (bottom surface: 520 cm2) connected with a recirculation system (temperature 20±1 °C and dissolved oxygen above 5 ppm). Animals have been hand-fed twice a day (at 9.00 a.m. and 5.00 p.m.) at a daily ratio of 1.5% body weight-1. Diets were tested in triplicate for 87 days. The fish were weighed at days 28, 57 and 87, and they were sampled at days 0, 57 and 87 for nutrient retention determination. One-way ANOVA with Newmann – Keuls’ post test were used to analyze data (P≤0.05). No differences in terms of palatability were observed and any diet has been consumed completely all through the experiment. At day 57, fish fed diet 2 (18%SBM) showed a statistically higher growth and nutrient utilization and a lower feed conversion rate than fish fed the diet 1 (fish meal based diet) and the diet 3 (30%SBM). At day 87, fish fed diet 1, 2 and 3 reached weights of 25.8±0.8g, 27.5±0.9g and 26.1±1.5g, respectively and no differences in performances or nutrient retention were found. Histopathological gut examinations have revealed no noticeable differences in the appearances of the intestines between any of diet groups. Intestinal mucosal cells presented well vacuolated upper, with well defined microvillar brush borders. On the basis of the results of this trial, SBM seems to be a good protein source for Egyptian sole and can be added in the diet up to 30% without any reduction in growth rate and minimal effect on gut histology.
Influence of soybean meal dietary levels on growth, feed utilization and gut histology of Egyptian sole (Solea aegyptiaca) juveniles
BONALDO, ALESSIO;MARIANI, LORENZO;PARMA, LUCA;GATTA, PIER PAOLO
2006
Abstract
The present study was undertaken in order to determine the effect of a dietary incorporation of soy bean meal (SBM, trypsin inhibitor activity 1.6 mg/g) on growth performance, nutrient utilization and gut histology of Egyptian sole Solea aegyptiaca. This species, which is genetically and morphologically close to Solea solea, is currently present in the Mediterranean Sea and reared in some Italian farms, using the same techniques for Solea solea production and it could represent a promising new species for Mediterranean aquaculture. Three isoproteic and isolipidic extruded diets (crude protein, 47%, crude fat, 20%) were formulated containing 0 (diet 1), 18 (diet 2) and 30% SBM (diet 3). 540 juveniles (initial body weight of 6.9±0.2g) were equally distributed into nine 150 litres squared tanks (bottom surface: 520 cm2) connected with a recirculation system (temperature 20±1 °C and dissolved oxygen above 5 ppm). Animals have been hand-fed twice a day (at 9.00 a.m. and 5.00 p.m.) at a daily ratio of 1.5% body weight-1. Diets were tested in triplicate for 87 days. The fish were weighed at days 28, 57 and 87, and they were sampled at days 0, 57 and 87 for nutrient retention determination. One-way ANOVA with Newmann – Keuls’ post test were used to analyze data (P≤0.05). No differences in terms of palatability were observed and any diet has been consumed completely all through the experiment. At day 57, fish fed diet 2 (18%SBM) showed a statistically higher growth and nutrient utilization and a lower feed conversion rate than fish fed the diet 1 (fish meal based diet) and the diet 3 (30%SBM). At day 87, fish fed diet 1, 2 and 3 reached weights of 25.8±0.8g, 27.5±0.9g and 26.1±1.5g, respectively and no differences in performances or nutrient retention were found. Histopathological gut examinations have revealed no noticeable differences in the appearances of the intestines between any of diet groups. Intestinal mucosal cells presented well vacuolated upper, with well defined microvillar brush borders. On the basis of the results of this trial, SBM seems to be a good protein source for Egyptian sole and can be added in the diet up to 30% without any reduction in growth rate and minimal effect on gut histology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
