Screening of nutrient digestibility, glycaemic response and gut morphology alterations in gilthead seabream (Sparus aurata) fed whole cereal meals

The effects of whole cereal meals on growth, nutrient digestibility, glycaemic response and gut morphology were studied in gilthead seabream juveniles. Groups of 30 fishes (in triplicate) were fed four isoproteic (47%) and isolipidic (16%) diets including 30% of wheat, corn, barley or rye meals. Growth performance was higher in fish fed the wheat diet than the rye diet. Feed efficiency and protein efficiency ratio were higher with the wheat and barley diets than in the other groups. There were no differences in apparent digestibility coefficients (ADCs) of dry matter, protein or lipids among diets. However, ADC of corn and barley starch was lower than that of wheat and rye starch. Average plasma glucose levels were lower in fish fed the barley diet. Plasma glucose peaked 10h after feeding in all groups except the corn group which peaked 8h after feeding. Shorter hyperglycaemia duration was observed in fish fed the corn diet (12h) than the other diets (>12h). Gut morphology was similar in all groups irrespective of the sampling point. Based on growth performance, feed utilization efficiency, ADC of starch and glycaemic response we can conclude that wheat and barley are more efficiently used than corn or rye by gilthead seabream juveniles and thus are the preferential cereal sources to be used as plant feedstuffs in diets for this species. Effective growth of fish at reduced costs. •Growth and starch digestibility were affected by cereal sources.•Glycaemia was lower in fish fed the barley diet.•None of the diets had an effect on gut morphology.•Wheat and barley were more efficiently used than corn or rye.