Effects of GroBiotic®-A supplementation on growth performance, body composition and liver and intestine histological changes in European Seabass (Dicentrarchus labrax) juveniles

Abstract

The effects of GroBiotic®-A supplementation on growth performance, body composition, liver and intestine histology in European seabass (Dicentrarchus labrax) juveniles were evaluated. The commercial GroBiotic®-A was added to diets at four different levels (0, 1, 2 and 3%), three replicates and fed 4 times a day (9:00, 11:30, 14:00, 16: 30 hours) for 60 days as ad libitum. Total 480 European seabass juveniles with a starting weight of 1.40±0.08 g were randomly stocked into 12 tanks with a volume of 1 m3 . At the end of the study, the changes observed in weight, feed conversion ratios (FCR) and survival rates were calculated as 6.69 ± 5.35-7.40 ± 5.47, 0.80 ± 0.18-0.88 ± 0.20 and 96.6 ± 1.51-100 ± 0.0, respectively. When the body composition of the control and treatment groups were compared, no statistically significant differences were observed between the protein and lipid values (p>0.05), except ash (p <0.05). Histological sections of intestinal tissue; the number of goblet cells was higher than that of the control group. The highest values were determined in the group supplemented 2% GroBiotic®-A. The highest microvillus length was found in the group added 1% GroBiotic®-A. It was detected an inverse relationship between microvillus length and contribution rates as the the GroBiotic®-A additive levels increased. Also, degeneration and necrosis was detected in hepatocyte cells of seabass juvenile fed with diets supplemented 2% and 3% GroBiotic®-A as well as increase of the number of fatty vacuoles in liver tissue due to the increase in the amount of GroBiotic®-A. In conclusion, when the growth parameters, body composition and histological data were evaluated together, the feeding group supplemented 1% GroBiotic®-A performed the best.