Se-Jin Lim

Evaluation of cottonseed and soybean meal as partial replacement for fishmeal in diets for juvenile Japanese flounder Paralichthys olivaceus

This study was conducted to investigate the effect of dietary supplementation of cottonseed and soybean meal (CS) on growth performance, feed utilization, and gossypol accumulation in juvenile (mean body weight 11 g) Japanese flounder Paralichthys olivaceus. Five isonitrogenous and isocaloric experimental diets (designated CS0, CS10, CS20, CS30, and CS40) containing 0, 10, 20, 30, and 40% CS mixture (1∶1 w/w) were formulated. After 9 weeks of feeding trial, fish fed all diets did not show significant differences in growth performances, feed utilization, and whole body compositions. Hemoglobin content gradually decreased (P<0.05) with increments of CS inclusion levels. There was a positive linear relationship between dietary gossypol and total liver gossypol contents. Free radical scavenging activity in the experimental diets gradually increased with increment of dietary CS inclusion. This finding indicates that the mixture of cottonseed and soybean meal with methionine and lysine supplementation could replace up to 40% of fishmeal protein in diets. However, 20% fishmeal protein replacement by dietary inclusion of cottonseed (9.4%) and soybean (8.7%) meal might be the optimum and safe level for the commercial use of CS in juvenile Japanese flounder.

Effects of Dietary Supplementation of Fermented Garlic Powder on Immune Responses, Blood Components, and Disease Resistance against Principal Fish Disease of Juvenile Olive Flounder, Paralichthys olivaceus in Low Temperature Season

We report non-specific immune responses and disease resistance against Vibrio anguillarum, Streptococcus iniae and Edwardsiella tarda by dietary supplementation of fermented garlic powder (FGP) in olive flounder for the first time. Four isonitrogenous (45% crude protein) and isocaloric (17.1 MJ/kg) diets were formulated to have 0%, 0.5%, 1% and 2% of the FGP (G-0, G-0.5, G-1 and G-2). The experimental diets were fed to juvenile olive flounder averaging 23.4 g in triplicate groups (90 fish/group) in a flow-through system. After a five-week feeding trial, healthy fish with similar sizes from each tank were selected and injected with 1 ml of three bacteria each to evaluate disease resistance of the fish. During the 5-week feeding trial, the weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio, and survival of the fish were not significantly affected by the experimental diets. However, feed intake was significantly lower (P<0.05) in the fish fed the G-2 diet compared with the control group. Hemoglobin, myeloperoxidase activity, cholesterol and HDL-cholesterol were not different between the dietary groups. However, hematocrit, nitroblue tetrazolium (NBT) activity, and lysozyme activity were increased (P<0.05) with an increment of dietary FGP. Plasma triglyceride of the fish fed the G-0.5 diet was significantly lower than that of fish fed the control diet. The cumulative mortality was lower in the fish fed diets containing FGP compared with the control group in the challenge test except for the bacteria Edwardsiella tarda. The results in this study indicate that dietary supplementation of FGP can enhance the non-specific immune responses and disease resistance of olive flounder against V. anguillarum and S. iniae. (Key words : Olive flounder, Fermented garlic powder, Non-specific immune response, Challenge test)

Effects of Dietary Supplementation of Two types of propolis on growth performance, feed utilization, innate immunity and disease resistance of olive flounder Paralichthys olivaceus

We investigated the effects of dietary supplementation of two types (powder or liquid) of propolis on innate immunity and disease resistance of olive flounder Paralichthys olivaceus against Edwerdsiella tarda. A total of 600 fish averaging 30 g were randomly distributed into 24 tanks in groups of 25. Three tanks were assigned to each of eight experimental diets: 0 (Control), 0.25, 0.5, 0.75 and 1 % propolis in powder form and 0.25, 0.5 and 1 % propolis in liquid form (PP0.25, PP0.5, PP0.75, PP1, LP0.25, LP0.5 and LP1, respectively). Fish were fed each experimental diet twice daily for four weeks to apparent satiation. At the end of the feeding trial, lysozyme and myeloperoxidase activities and total immunoglobulin level were significantly higher in fish fed the PP1 and LP0.5 diets compared to those fed the control diet. The PP1 diet was also associated with a significant increase in anti-protease activity compared to the control diet. After challenge with E. tarda, fish fed the LP0.5 diet showed numerically higher survival compared to the other groups. This study indicates that non-specific immune responses of olive flounder can be enhanced by dietary supplementation with powder and liquid forms of propolis, and that the optimal level would be 1% in powder form or 0.5% in liquid form. It seemed that growth performance and feed utilization are not affected by the propolis supplementation in diets for olive flounder.

Effects of Dietary Supplementation with Nucleotide on Growth Performance, Feed Utilization, and Non-Specific Immune Responses of Nile Tilapia Oreochromis niloticus

The present study examined the effects of dietary supplementation with nucleotide (inosine monophosphate product, IMP) on the growth performance, feed utilization, and non-specific immune responses of juvenile tilapia Oreochromis niloticus. Triplicate groups of tilapia (initial body weight, g) were fed experimental diets containing 0%, 0.05%, 0.1%, and 0.2% IMP. Fish were fed six times a day until apparent satiation for 13 weeks. At the end of the feeding trial, final body weight and food utilization of fish fed 0.1% IMP were significantly higher than those of fish fed the control diet. Results of hematological parameters were not affected by dietary IMP. However, blood protein level was significantly higher in the 0.05% treatment, as compared to that of the control and 0.2% IMP diets. Myeloperoxidase activity was higher in fish fed 0.1% IMP than in fish fed the control and 0.2% IMP diets. These results suggest that dietary supplementation with IMP can enhance the growth performance, feed utilization, and innate immune response of juvenile tilapia. The optimal IMP supplementation level appears to be 0.1% in practical feed formulations for tilapia.