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The beneficial effects of Bacillus subtilis C-3102 and Saccharomyces cerevisiae type 1 were tested in red sea bream (Pagrus major) feeds. A basal diet (control) and two other diets were prepared by supplementation with B. subtilis C-3102 (PB) or S. cerevisiae type 1 (PY). After 60 days, both probiotic-supplemented groups exhibited significant enhancement in growth performance, the protein efficiency ratio (PER), and digestive enzyme secretion (protease and amylase) compared to the control group (PPPP<0.05). Catalase activity was also significantly decreased in both probiotic groups, with relatively lower activity observed in the PY group (P<0.05). Both probiotic groups showed considerably increased tolerance to freshwater exposure (P<0.05). In conclusion, B. subtilis C-3102 and S. cerevisiae type 1 can be used as functional probiotics to enhance the growth performance, digestion capacity, gut morphology, immune response, and stress resistance of the red sea bream with relatively higher efficiency by B. subtilis C-3102.

We evaluated the efficacy of mozuku fucoidan supplementation to alternative dietary proteins used in fish meal (FM) replacement to enhance growth, immunity, and stress resistance of Pagrus major. Seven isonitrogenous (45% protein) experimental diets were formulated where diet 1 (D1) was FM-based control diet. Diets 2 to 7 were formulated by replacing 25, 50, and 75% of FM protein with soy protein isolate (SPI) protein, and each replacement level was supplemented without or with fucoidan at 0.4% for diet groups D2 (FM25), D3 (FM25Fu), D4 (FM50), D5 (FM50Fu), D6 (FM75), and D7(FM75Fu), respectively. Each diet was randomly allocated to triplicate groups of fish (4.1 g) for 56 days. Significantly higher weight gain and specific growth rate were observed in fish fed FM50Fu diet group, and it was not differed (P > 0.05) with fish fed FM25Fu diet group. FM-based control diet showed intermediate value, and it was not differed (P > 0.05) with or without fucoidan-supplemented ≤ 50% FM replacement groups and FM75Fu diet group. Significantly lower growth performances were observed in FM75 diet group. At each replacement level, fucoidan-supplemented groups showed nonsignificant improvement of feed utilization performances. Fish fed fucoidan-supplemented diets showed best condition of oxidative and freshwater stress resistance. Lysozyme activity, NBT, and peroxidase activity showed higher (P > 0.05) values in fucoidan-supplemented groups compared with the non-supplemented groups. Catalase activity was significantly lower in FM75Fu diet group. Catalase activity is significantly influenced by the interaction effects of fucoidan and FM replacement level. In conclusion, fucoidan supplementation could increase the efficiency of utilizing SPI (≥ 75%) without any adverse effects on red sea bream performance.

In larviculture of marine finfish, Tisochrysis lutea cultured cells have a potential to be a sustainable enrichment diet for rotifers due to its de novo synthesis of docosahexaenoic acid (DHA). To improve its effectiveness in rotifer enrichment for later larviculture, we determined which growth phase of T. lutea can enhance DHA in polar lipids (PLs) in Brachionus plicatilis sp. complex rotifers without reducing their vigor. Tisochrysis lutea was harvested at logarithmic growth phase, deceleration growth phase, and stationary phase. The ambient concentrations of phosphorus (P) and nitrogen (N), and fatty acid composition of microalgae were measured. P was limited between logarithmic and deceleration growth phases, followed by N starvation in stationary phase. Total lipid DHA was lowest in logarithmic growth phase, whereas DHA levels increased in deceleration growth phase and maintained at high levels even in stationary phase. PL-DHA also increased during deceleration growth phase, although its abundance dropped during stationary phase. In a rotifer enrichment trial, T. lutea harvested in each phase were fed to B. plicatilis sp. complex rotifers for 12 h. The highest PL-DHA value for cells in deceleration growth phase reflected the concentrations of the rotifers. No significant differences were found in rotifer growth rate and egg ratio. Rotifers fed cells in deceleration growth phase exhibited higher swimming speeds than those fed the other cells, potentially linking to increased larval capture success. Therefore, we recommend the deceleration growth phase as an optimal timing for T. lutea harvest for the effective enrichment of B. plicatilis sp. complex rotifers.

A 60-day experiment was designed to assess the effect of different ratios of fish meal (FM): camelina meal plant protein (CM) on growth response and relative gene expression of growth-promoting factors, feed utilization potency, digestive enzymes activities, apparent digestibility (ADC), stress response, non-specific immunity of Pagrus major. Four isonitrogenous (490.7 g/kg of crude protein) and isolipidic (91.5 g/kg total lipid) experimental diets were formulated and designated as camelina meal (CM0), soyabean meal (SBM20.5), CM20.5, and CM33 based on protein contents. At the end of the feed trial, significantly higher (p &lt, 0.05) weight gain, specific growth rate, and feed intake but lower feed conversion ratio were recorded in fish fed CM0, SBM20.5, and CM20.5 than fish fed CM33. The lowest growth, feed utilization, enzyme activity, and digestibility were recorded in fish fed CM33. Significantly higher pepsin, amylase, and protease activities were observed in fish fed CM0, SBM20.5, and CM20.5 diets than fish fed CM33. The highest ADC of protein was recorded in fish fed CM0, SBM20.5, and CM20.5 diets. Hematocrit levels were depressed CM33 while total serum protein, total cholesterol, triglyceride, blood urea nitrogen, total bilirubin, aspartate aminotransferase, and alanine aminotransferase were not significantly changed by the inclusion of CM. Non-specific immune variables (lysozyme activity, peroxidase activity in serum and nitro blue tetrazolium) in fish fed CM0, SBM20.5, and CM20.5 were significantly higher than in fish fed CM33 diet. The superoxide dismutase of fish fed CM20.5 was not significantly different from CM0 and SBM20.5 (p &gt, 0.05). Catalase and low salinity stress test show that CM0, SBM20.5, and CM20.5 were not significantly (p &gt, 0.05) different, while CM33 was significantly lower than the rest of the diets. TBARs show that CM20.5 and CM33 diets were significantly different (p &lt, 0.05), but CM20.5 was not significantly different from SBM20.5. Significantly higher hepatic IGF-1 and IGF-2 mRNA expression was found in fish-fed diet groups CM0, SBM20.5, and CM20.5 than fish fed CM33. The present study indicated that the addition of CM up 205 kg/kg to diet maintains growth, digestive enzymes, nutrient digestibility, immunity, stress resistance, and feed utilization efficiency of red sea bream.

Euryhaline rotifer belonging to the genera Brachionus are often used as live feed for first feeding marine finfish larviculture. Two common rotifer enrichments, a single usage of docosahexaenoic acid (DHA)-enriched Chlorella vulgaris and a combination of DHA-enriched C. vulgaris and salmon roe emulsion oil were used to assess: (i) nutritional status of rotifers and, (ii) performance when rotifers were fed to Pagrus major and Paralichthys olivaceus larvae from 2 to 15 days after hatching (DAH). Both rotifer enrichment treatments were found to be nutritionally effective with high unsaturated fatty acid (HUFA) content, especially in the combined treatment with significantly higher eicosapentaenoic acid (EPA). Despite deficient levels of EPA, DHA-enriched C. vulgaris was found to be a suitable enrichment for rotifer and also had positive response in survival, growth and trypsin activity in both P. major and P. olivaceus. DHA-enriched C. vulgaris only treatment had higher rotifer population growth (13% higher), egg bearing capacity (7% higher), almost double the soluble protein content and generally higher free amino acid content. Oxidation of lipids in the combined diet due to its high-saturated fatty acid content could be a possible cause to the inferior performance of the combined treatment. Both P. major (20.1 ± 10.1%) and P. olivaceus (12.3 ± 3.87%) suffered low survival and lower gut content in the combined treatment especially during periods of significant growth in both species (7–11 DAH). Despite high HUFA content in the combined treatment, this study revealed that consideration of free amino acids and soluble protein content as parameters of nutritional indicators for first feeding P. major and P. olivaceus should not be discounted.

A 56‐day feeding trial was carried out to evaluate the interactive effects of chemically synthesized astaxanthin (Ax) and cholesterol (CHO) on the performances of kuruma shrimp juveniles. Six experimental diets containing 2 levels of Ax (0 and 0.6 g/kg diet) and 3 levels of CHO (0, 6 and 20 g/kg diet) were formulated in 2 × 3 factorial design. The results indicated that the interactions between dietary CHO and Ax were not significant on survival, growth performances, body proximate analysis, immune response and freshwater stress test. Significantly, better pigmentation performances and Ax contents of different parts of juveniles (whole body, muscle, carapace and head) were observed in higher Ax (Ax₀.₆)‐supplemented groups. Meanwhile, interactions of dietary Ax and CHO were also found on colour reading parameters and whole‐body Ax contents. In addition, juveniles fed with the diet containing Ax at 0.6 g/kg diet in addition to CHO at 0, 6 and 20 g/kg diet showed better performances on digestive enzyme activities (protease, lipase and amylase) of hepatopancreas than 0 g Ax/kg diet supplemented with CHO at 0, 6 and 20 g/kg diet. It was concluded that dietary Ax and CHO functioned interactively.

This study investigated the effects of bovine lactoferrin (bLf) on the body surface defense factors, stress response to fresh water exposure, and anti-parasitic effects against Neobenedenia girellae in amberjack (Seriola dumerili) juveniles. In the first trial, amberjack juveniles were fed test diets supplemented with four different levels of bLf (0, 500, 1000, and 2000 mg kg−1) for 4 weeks to determine the appropriate bLf supplement level and feeding duration, and stress responses to short-term fresh water exposure followed by recovery at ambient salinity were also measured. This showed that a diet supplemented with ≥1000 mg bLf kg−1 for 2 weeks improved skin mucus production, non-specific defense factors, and mitigated stress. In the second trial, amberjack juveniles were fed diets supplemented with 0 and 1000 mg bLf kg−1 for 2 weeks and challenged by N. girellae oncomiracidia. It was found that fish that had been fed a diet supplemented with 1000 mg bLf kg−1 had significantly fewer parasites than fish that had been fed the unsupplemented control diet. Together, these results suggest that dietary bLf enhances defense ability the body surface, mitigates low-salinity stress, and enhances anti-parasitic effects against N. girellae oncomiracidia in amberjack juveniles.

A feeding trial was conducted to assess the effects of dietary Nannochloropsis sp. as powder or lipid on survival, growth performance and fatty acids content in Kuruma shrimp juvenile. Seven isonitrogenous, isolipidic and isocaloric diets were formulated to contain in first group graded levels of Nannochloropsis powder: 0% (CON, control diet), 4% (A), 7% (B) and 10% (C) dry matter then in second group algae oil proportionally extracted (AE, BE and CE, respectively). The feeding trial was conducted for 50 days. The results showed that the substitution of fish oil (FO) with algae powder diets A, B and C significantly (P

A 56‐day feeding trial was done to investigate the interactive effects of astaxanthin (Ax) and vitamin E (α‐Toc) on the performance of kuruma shrimp (Marsupenaeus japonicus). A 2 × 3 factorial experiment was conducted with six experimental diets containing two levels of Ax (0 and 0.6 g/kg diet [Ax₀ and Ax₀.₆]) and three levels of α‐Toc (0, 0.2 and 1 g/kg diet [α‐Toc₀, α‐Toc₀.₂ and α‐Toc₁]). The results indicated that growth performance was significantly (p 0.05) effects were found between dietary α‐Toc and Ax on total haemocyte count and tolerance against freshwater, dietary Ax and α‐Toc supplementation showed better performance on these two parameters. It was concluded that dietary Ax and α‐Toc functioned synergistically, and the shrimp fed with the diet containing 0.6 g Ax/kg diet Ax and 0.2 g α‐Toc/kg diet showed improved growth and pigmentation performance compared with the other groups in the current study.

A 56-day feeding trial to evaluate the responses of red seabream (initial weight: 1.8 ± 0.02 g) to the substitution of fish oil (FO) with camelina oil (CO) at different ratios was conducted. The control diet formulated at 46% CP (6F0C) contained only FO without CO, from the second to the fifth diet, the FO was substituted with CO at rates of 5:1 (5F1C), 4:2 (4F2C), 3:3 (3F3C), 2:4 (2F4C), and 0:6 (0F6C). The results of the present study showed that up to full substitution of FO with CO showed no significant effect on growth variables BW = 26.2 g–28.3 g), body weight gain (BWG = 1275.5–1365.3%), specific growth rate (SGR = 4.6–4.7), feed intake (FI = 25.6–27.8), feed conversion ratio (FCR = 1.0–1.1), biometric indices condition factor (CF = 2.2–2.4), hepatosomatic index (HSI = 0.9–1.1), viscerasomatic index (VSI = 7.5–9.5), and survival rates (SR = 82.2–100) with different FO substitution levels with CO. Similarly, there were no significant differences (p &lt, 0.05) found in the whole-body composition except for the crude lipid content, and the highest value was observed in the control group (291 g/kg) compared to the other groups FO5CO1 (232 k/kg), FO4CO2 (212 g/kg), FO2CO4 (232 g/kg) and FO0CO6 (244 g/kg). Blood chemistry levels were not influenced in response to test diets: hematocrit (36–33%), glucose (Glu = 78.3–71.3 mg/dL), total protein (T-pro = 3.1–3.8 g/dL), total cholesterol (T-Chol = 196.0–241 mg/dL), blood urea nitrogen (BUN = 9.0–14.6 mg/dL), total bilirubin (T-Bil = 0.4–0.5 mg/dL), triglyceride (TG = 393.3–497.6 mg/dL), alanine aminotransferase test (ALT = 50–65.5 UL/L), aspartate aminotransferase test (AST = 38–69.3 UL/L). A remarkable modulation was observed in catalase (CAT) and superoxide dismutase (SOD) activities in the liver, as CAT and SOD values were lower with the complete FO substitution with CO (0F6C), and the highest values were observed in the control and (4F2C). This study indicates that red seabream may have the ability to maintain LC-PUFAs between tissues and diets, and CO substitution of FO could improve both lipid metabolism and oxidation resistance as well as maintain digestibility. In conclusion, dietary FO can be replaced up to 100% or 95% by CO in the diets of red seabream as long as n-3 HUFA, EPA, and DHA are incorporated at the recommended level.

The euryhaline copepod Pseudodiaptomus inopinus play important roles in coastal waters as vectors of docosahexanoic (DHA) and eicosapentaenoic (EPA) acids for larval fish. While DHA and EPA in polar lipids (PLs) are more effective for fish larval development than non-polar lipid forms (NLs), there is little knowledge how much these lipids are accumulated in copepods from microalgae and are effective for early development of fish larvae. We report PLs fatty acid profiles of P. inopinus fed DHA-poor microalgae and evaluate its significance as a food source for larvae development of Pagrus major, compared with DHA-enriched rotifers. Copepods and rotifers were fed a mixed diet of three algal species (Phaeodactylum tricornutum, Tisochrysis lutea, and Pavlova lutheri), in addition of DHA-supplemented Super Fresh Chlorella (SFC) for rotifers. Compared with SFC, the algal mixture had higher EPA but lower DHA. Copepods had higher DHA and EPA in total lipids than rotifers fed each diet. Copepod PLs were specifically enriched with DHA and their contents were higher than both rotifers. On the other hand, PLs EPA contents were comparable between preys, indicating that copepods selectively fortified the PLs. Fish culture experiment showed that larvae fed copepods had higher growth than those fed SFC-enriched rotifers. Principal component analysis for each organism fatty acid composition emphasized trophic modification of DHA by copepods toward larval fish. This study highlighted that P. inopinus contribute to enhanced growth of coastal larval fish by efficiently transferring DHA via copepod fatty acid metabolism.

We determined the supplementation effects of dietary fucoidan on growth, immune responses, blood characteristics, and oxidative stress resistance of juvenile red sea bream. A fishmeal (FM)-based basal diet supplemented with 0% (D1, control), 0.05% (D2), 0.1% (D3), 0.2% (D4), 0.4% (D5), and 0.8% (D6) mozuku fucoidan to formulate six experimental diets. Each diet was randomly allocated to triplicate groups of fish (3.8 g) for 60 days. Results showed that fish-fed diet D5 showed significantly higher (P

This study aimed to investigate the effects of a superoptimal temperature on growth, body composition, body size heterogeneity, and relationships among these factors in juvenile yellowtail. Fish (mean body weight = 24 g) were tagged individually and reared for 70 days under two different water temperature regimes [optimal (25 °C) and superoptimal (30 °C)]. After rearing, fish reared at 30 °C showed lower survival, less food, feed and protein utilization, significantly lower growth performance, and a lower hepatosomatic index than fish raised at 25 °C. Variations in body indices among individuals were larger for fish reared at 30 °C than for fish reared at 25 °C. Mean whole body protein content was significantly lower in fish reared at 30 °C than fish reared at 25 °C. In addition, several glucogenic and/or aromatic amino acids were lower in fish reared at 30 °C than in fish reared at 25 °C. Whole body lipid levels tended to be lower in fish with lower body weight reared at 30 °C. These results suggest that fish raised at 30 °C will have lower growth performance, and lower concentrations of specific amino acids. Moreover, heterogeneity in body size and body lipid content is expanded by a superoptimal temperature.

This study evaluated the effects of dietary substitution of fishmeal by graded levels of a blend composed of Aspergillus oryzae fermented rapeseed meal [0% (RM0), 25% (RM25), 50% (RM50), 75% (RM75) and 100% (RM100)] on growth performance, haemato-immunological responses and antioxidative status of Pagrus major (average weight 5.5 ± 0.02 g). After 56 days, growth performances were significantly improved in fish fed RM25 diet compared to control (P

This study evaluated the effects of chemically synthesized astaxanthin (Ax) on growth performance, survival, stress resistance, immune responses, fatty acid contents, and pigmentation of juvenile kuruma shrimp (Marsupenaeus japonicus). Six dietary levels of Ax (0, 200, 400, 800, 1200, and 1600 mg kg−1 diet) were added to a baseline diet. The feeding trial was conducted for 56 days. The results showed that juveniles fed diets supplemented with Ax exhibited better growth performance, final body weight (FBW), body weight gain (BWG), and specific growth rate (SGR) than the control group, with the best performance exhibited by in the 400 mg kg−1 diet Ax supplemented group (P

We determined the dietary inosine effects in gradually replaced fishmeal (FM) with soybean meal (SBM) protein-based diets on growth, digestibility, immunity, stress resistance and gut morphology of juvenile amberjack. Seven experimental diets were formulated to be nearly isonitrogenous (48% crude protein) where diet 1 (D1) was FM based control diet. Diet 2 to 7 were formulated by replacing 25, 50 and 75% of FM protein with SBM and each replacement level was supplemented with or without inosine at 0.6% for diet groups D2(FM25INO), D3(FM25), D4 (FM50INO), D5(FM50), D6(FM75INO) and D7(FM75), respectively. Triplicate groups of fish (24.9 g) were randomly stocked in 200 L polycarbonate tanks at a rate of 24 fish per tank and fed to satiation twice daily for 56 days. After the feeding trial, final weight, specific growth rate, and weight gain were not significantly different among the treatments with that of the 50% replacement containing inosine. Without inosine-supplemented 50% replaced group and with or without inosine-supplemented 75% replaced group showed reduced growth and feed utilization performances. The apparent digestibility coefficients of dry matter, protein and lipid were significantly higher in control and other replacement groups with inosine supplementation. In the case of oxidative stress parameters, fish fed inosine-supplemented diets showed the best condition. Stress resistance against low salinity exposure (LT50), significantly increased with inosine supplementation and was highest in inosine-supplemented 50% replacement diet group. Total serum protein (TSP), alternative complement pathways (ACH50), lysozyme activity (LA), bactericidal activity (BA) and peroxidase activity (PA) tended to be higher in inosine-supplemented groups compared to the non-supplemented groups. Simultaneously, enterocyte height, fold height, and microvillus height of the anterior and posterior enteric sections increased significantly with the inosine supplementation. Results of the study indicated that at least half of the fishmeal could be replaced with soybean meal and supplementation of inosine in the diets of juvenile amberjack. Moreover, inosine administration in 50 to 75% FM replacement groups could be helpful to improve the digestibility, immune responses, stress resistance, and intestinal health condition of fish.

Three feeding studies were conducted to investigate whether dietary soybean lecithin (SBL) enhanced feed intake of non-fish meal, SPC-based diet, in yellowtail, and also to clarify which fraction of phospholipid (PL) was effective to enhance feed intake. In experiments 1 and 2, fish were fed SBL level at 0%–5%, and it was revealed that the daily feeding rate (DFR) of fish was significantly higher for SBL 2% than for SBL 0%, while a further increase of SBL in the diet did not additionally increase the DFR. Moreover, the DFR of fish fed a diet without feeding stimulants (FS) was the lowest among the dietary treatments, indicating that the SBL does not have an effect of enhancing feed intake in yellowtail. In experiment 3, fish were fed a diet with several products containing PL at 2%. Phosphatidylcholine and phosphatidylinositol concentrations in these products positively correlated to the DFR of fish. This result revealed that these two fractions in the SBL are effective for enhancing feed intake of yellowtail when FS is present in the diet.

Eugenol, which has been used as an anesthetic for fish, was administered to Japanese flounder, Paralichthys olivaceus (127 ± 50.8 g), by bath treatment at concentrations of 0.025, 0.125, and 0.25 mL/L seawater for 10 min and intramuscular injection at 40 μL/fish to investigate the pharmacokinetic characteristics of eugenol in the plasma of Japanese flounder. In the bath treatment test, plasma eugenol concentration increased with increasing eugenol concentration up to 0.125 mL/L and reached steady state within 5 min. After a 10-min bath treatment in 0.25 mL/L eugenol, plasma eugenol concentration was about 58.4 µg/mL. After transfer into running seawater, plasma eugenol concentration decreased biphasically with half-lives of 0.0296 h (α-phase) and 0.289 h (β-phase). The AUC0000→0800 was about 16.5 µg h/mL. In administration by intramuscular injection, plasma eugenol concentration increased rapidly after administration and decreased biphasically with half-lives of 0.0329 h (α-phase) and 8.08 h (β-phase). The AUC0000→0800 was about 52.5 µg h/mL. In both methods of administration, Japanese flounder with average weight of 127 g were effectively anesthetized when plasma eugenol concentrations were between 2.19 and 4.88 µg/mL.

In the present study we investigate the dietary administration effects of uridine monophosphate (UMP) to enhance the growth, hematological profile, innate and adaptive immune functions and stress resistance of juvenile red sea bream, Pagrus major . A casein fishmeal based semi-purified basal diet supplemented with 0% (control), 0.1% (UMP-0.1), 0.2% (UMP-0.2), 0.4% (UMP-0.4) and 0.8% (UMP-0.8) purified UMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (mean initial weight 2.9 g) for 56 days. In general dietary UMP supplementation tended to improve growth performances (final body weight, % weight gain and specific growth rate), in which significantly higher performances were found in diet group UMP-0.4 followed by diet groups UMP-0.8, UMP-0.1 and UMP-0.2. UMP supplementation resulted increased feed conversion efficiency and protein efficiency ratio and significantly higher value (P 0.05) with dietary UMP supplementation. Fish in control group without UMP supplementation showed significantly lower growth and feed utilization performances. The capabilities of enhancing immune responses of fish fed UMP supplemented diets were detected by nonspecific and acquired immune parameters measured in this study. Peroxidase activity (PA) was significantly higher in fish fed diet group UMP-0.8 and higher (P Vibrio anguillarum . In the 15th day after vaccination, significantly higher agglutination antibody titer was found in diet group UMP-0.4 and simultaneously other supplemented diet groups showed intermediate values. In terms of oxidative stress, diet group UMP-0.4 showed best condition with low oxidative stress and high antioxidant levels. Moreover, the fish fed UMP supplemented diets had better improvement (P

A 50-day feeding trial was conducted to determine the effects of dietary inosine on growth performance, immune responses, oxidative stress and gut morphology of juvenile amberjack, Seriola dumerili. Five isonitrogenous (52% crude protein) and isolipidic (14% crude lipid) semi-purified test diets were prepared by supplementing incremental levels of dietary inosine nucleoside at 0% (D1, control), 0.1% (D2), 0.3% (D3), 0.6% (D4) and 0.9% (D5), respectively. Triplicate groups of juvenile with an initial average weight of approximately 26 g were randomly stocked in fifteen, 200L polycarbonate tanks at a stocking density of 20 fish per tank. The fish were hand-fed twice daily to apparent satiation level. At the end of the feeding trial, final body weight (g), weight gain (%) and specific growth rate (% day− 1) were significantly (P

The effective use of distillery by-products of the shochu sweet potato has long been considered as a rich source of protein, fiber, amino acids, fatty acids, probiotics with a great potential as a functional feed for animals. This study applied fermented by-product of Shochu distillery (FBPSD) and salmon roe emulsion oil for rotifer enrichment to evaluate its effects on the: (i) nutritional composition of rotifers and (ii) feeding responses of Paralichthys olivaceus larvae when fed with enriched rotifers. The salmon roe oil enrichment was set as a control diet and FBPSD was supplemented at different doses (1, 5 and 10 % based on the salmon roe oil amount). The results showed that the rotifers supplemented with FBPSD at 5 and 10 % significantly enhanced protein, carbohydrate, and HUFA content. Similarly, the activity and expression profiles of targeted enzymes including trypsin, chymotrypsin, lipase and amylase effectively responded at early and middle-metamorphosis of the larvae to 5 and 10 % enrichment regiment. These two treatments were also found to be better supported in energy metabolism evidenced by Cytochrome-C-Oxidase (cox) and ATPase-pk (atp) gene expression in the larvae. Moreover, the expression levels of immune-related genes (IL-10, IL-1β, TNF-α, P2Y6) and antioxidant-related genes (SOD, CAT) were significantly improved at 5 and 10 % of FBPSD. Cessation of feeding and delay in growth during the metamorphic process was also molecularly demonstrated. Larvae suffered low survival (24.5–25.3 %) in control and 1 % supplementation of FBPSD, but significantly improved at 5 and 10 % (36.4–38.7%). However, the growth performance of larval fish was not remarkable after 40 days of culture. The results of this study revealed that FBPSD could be considered as a potential supplementary enrichment for live feed in fish larviculture, especially at 5 and 10 % rotifer enrichment dosage.

There is no definitive evidence associated with administration duration of nucleotide on aquaculture organisms. This study evaluates the long-term feeding effects of cytidine monophosphate (CMP) nucleotide as functional supplement on growth and health conditions of red sea bream, Pagrus major. A formulated basal diet added with 0% (control), 0.2% (CMP-0.2) and 0.4% (CMP-0.4) individual CMP nucleotide to prepare three experimental feeds. Each experimental feed was fed to triplicate tanks of red sea bream (3.0 ± 0.01 g) for 150 days. At day 50th, growth performances were influenced significantly by dietary CMP inclusion and fish fed CMP-0.4 diet showed significantly higher value. In day 100 and 150 growth performances also non-significantly enhanced by CMP supplementation. Feed utilization performances also showed improved values in nucleotide included diets compared to the non-supplemented control diet (P > 0.05). No significant changes observed on measured hematological parameters by nucleotide administration duration. Lysozyme activity (LA) and total serum protein (TSP) significantly rose to their highest level on 50 days in CMP-0.4 diet group. In 100 and 150th day supplementation also improved TSP and LA values and it reaches maximum in CMP-0.2 diet group (P > 0.05). Oxidative radical production (nitro-blue-tetrazolium assay) and the activity of peroxidase and catalase were not affected significantly with feeding nucleotide in all sampling days. Supplementation of nucleotide improved oxidative stress tolerance capacity. Remarkably, CMP-0.2 diet group showed the least oxidative stress condition in 50th and 100th day. In 150th day fish showed acceptable but reduced oxidative stress resistances. On the basis of the overall findings, finally we concluded that, CMP nucleotide administration regime influences the optimum growth, health performance and immune response of Pagrus major and its mostly after feeding for 50 days, but not after 100 days.

A feeding trial was conducted to determine the efficacy of nucleotide related products on growth, blood chemistry, oxidative stress and growth factor gene expression of juvenile red sea bream. Five experimental diets were formulated to contain 49% protein, 11% lipid and the diet without nucleotide related product supplementation was the control (D1). Nucleotide related products like; nucleoside by-products (NBPs) and inosine were supplemented at 1, 3 and 0.03, 0.1% consecutively with basal ingredients of D1 and named as D2, D3 & D4 and D5 respectively. Experimental diets were fed to triplicate groups of fish for 60 days. Fish fed diet D5 showed significantly the highest final body weight and % weight gain followed by the diet groups D2 and D4. Fish fed control group showed the lowest growth performance and were not differed significantly with diet group D3. Feed conversion ratio and protein efficiency ratio were also significantly higher in diet group D5, whereas the other supplemented group showed intermediate value. A wide variation in some of the blood parameters was observed. In case of oxidative stress parameters, fish fed inosine supplemented diets showed the best conditions because they performed better under oxidative stress conditions as well as had the highest tolerance against oxidation. Among NBP supplemented groups, diet group D2 also showed acceptable conditions of oxidative stress tolerance. Stress resistance against low salinity exposure (LT50) also increased with dietary supplementation and it was significantly the highest in fish fed diet group D5. Total serum protein, serum lysozyme activity and total peroxidase content tended to be higher (P > 0.05) in NBP and inosine supplemented diet groups. In numerically higher hepatic IGF-1, mRNA expression was found in diet groups D2 and D4. However, IGF-1 and IGF-2 mRNA expressions were not significantly altered by dietary supplementations in the present study. Considering overall performance of the present study, we concluded that inosine and low concentration of NBP (1%) could be effectively used as dietary supplements for better growth and health performance of Pagrus major. Statement of relevance In this study industrial by-products, nucleoside by-products and relatively low cost nucleoside, inosine has been evaluated as potential functional nutrients for marine fish such as red sea bream. Utilization of these functional supplements will help to reduce nucleotide administration cost in fish feed as well as to develop low fishmeal based functional aquafeed in the near future.

A usual strategy in modern aquaculture to combat production bottlenecks associated with intensification is preventive health care through the use of consumer and environment-friendly alternatives including probiotics. The current study evaluates the influence of Lactobacillus rhamnosus (LR), a lyophilized probiotic bacterium, on health status and performance of red sea bream (Pagrus major). Probiotics were incorporated in the diets at four different concentrations: 0 (control diet, LR0), 10(2) (LR1), 10(4) (LR2) and 10(6) (LR3) cells g(-1) and diets were administered to the fish for a period of 8 weeks. After the feeding trial, final body weight, body weight gain, specific growth rate, protease activity, protein digestibility, Lactobacillus sp. intestinal count, and superoxide dismutase were significantly higher in all probiotic-fed groups (P 0.05). In addition, lipid and dry matter digestibility, reactive oxygen metabolites, biological antioxidant potential, and humoral and mucosal immune parameters including (total serum protein, alternative complement pathway, bactericidal and peroxidase activities) were also significantly elevated in fish fed probiotic supplementations being the effects dose-dependent. All growth, feed utilization, immune and oxidative parameters were significantly improved following probiotic administration. Present results revealed that L. rhamnosus is a promising probiotic candidate employed to help red sea bream protect themselves, thus promoting safe farming that would be less dependent on chemotherapy against infectious diseases.

Environmental stressors caused by inadequate aquaculture management strategies suppress the immune response of fish and make them more susceptible to diseases. Therefore, efforts have been made to relieve stress in fish by using various functional feed additives in the diet, including probiotics. The present work evaluates the effects of Lactobacillus rhamnosus (LR) on physiological stress response, blood chemistry and mucus secretion of red sea bream (Pagrus major) under low salinity stress. Fish were fed four diets supplemented with LR at [0 (LR0), 1 × 102 (LR1), 1 × 104 (LR2) and 1 × 106 (LR3) cells g−1] for 56 days. Before stress, blood cortisol, urea nitrogen (BUN) and total bilirubin (T-BIL) showed no significant difference (P > 0.05), whereas plasma glucose and triglyceride (TG) of fish-fed LR2 and LR3 diets were significantly lower (P 0.05). In addition, the fish that received LR-supplemented diets showed significantly higher tolerance against low salinity stress than the fish-fed LR-free diet (P

A feeding trial was conducted to determine effects of dietary inosine on growth, immune responses, oxidative stress resistance and intestinal morphology of juvenile red sea bream. A semi-purified basal diet supplemented with 0 (D1, control), 2 g kg−1 (D2), 4 g kg−1 (D3), 6 g kg−1 (D4) and 8 g kg−1 (D5) dietary inosine, respectively, to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (initial weight: 8 g). After 50 days of feeding trial, fish fed diets with 4 g kg−1 inosine had the highest (p

Inosine and inosine monophosphate (IMP) are the most extensively studied specific nucleotide for feeding stimulation research rather than using as functional nutrients for potential growth and health benefit of aquatic species. Therefore, a 10-week feeding trial was conducted to determine comparative effects of inosine and IMP as functional nutrients on growth performance, immune responses, stress resistance and intestinal morphology of juvenile red sea bream (Pagrus major). Casein based semi-purified basal diet was formulated to contain 54% protein, 11% lipid, without inosine and IMP supplementation (Control). Four levels of inosine nucleoside (0.2, 0.4, 0.6 and 0.8% for diet groups INO-0.2, INO-0.4, INO-0.6 and INO-0.8 respectively) and IMP nucleotide (0.2, 0.4, 0.6 and 0.8% for diet groups IMP-0.2, IMP-0.4, IMP-0.6 and IMP-0.8 respectively) were added to the basal diet. Each diet was randomly allocated to triplicate groups of fish with initial average weight of 6.6 g. The results indicated that dietary inosine and IMP supplementations tended to improve growth performances, in which one of the best ones was found in diet group IMP-0.6, but the values did not significantly differ from those in diet groups IMP-0.4 and INO-0.4, respectively. Superoxide dismutase, peroxidase and bactericidal activity were significantly influenced by dietary supplementation of inosine and IMP. However, the values of these parameters were not significantly different among diet groups INO-0.4, IMP-0.4 and IMP-0.6. Total serum protein, catalase and lysozyme activity were also improved (P > 0.05) by dietary supplementation of inosine and IMP. Supplementations improved both freshwater stress and oxidative stress resistances. Fish fed diet groups INO-0.4 and IMP-0.6 showed the least oxidative stress condition. Inosine and IMP supplementations significantly increased enterocyte height (hE), fold height (hF) of both anterior and posterior intestine and microvillus height (hMV) of posterior intestine compared to those of the control. The highest hF observed in diet group IMP-0.4 and the mean value was not significantly different from those in other IMP diets, INO-0.4 and INO-0.6, respectively. Significantly highest anterior hE and posterior hF, hE and hMV observed in diet group INO-0.4. However, no significant difference of posterior hF observed between INO-0.4 and IMP supplemented diet groups. Fish fed supplemented diets also showed improved survival compared to control (P > 0.05). Considering overall performances, it can be concluded that diet groups INO-0.4 and IMP-0.4 showed relatively better performance among inosine and IMP supplemented diet groups respectively compared to control. Furthermore, diets supplemented with either inosine or IMP at 0.4% are beneficial to promote growth, immune responses, stress resistance and intestinal health condition of juvenile red sea bream. Statement of relevance In this study inosine and inosine monophosphate has been evaluated as potential functional nutrients for marine fish such as red sea bream. Since supplementations of such immunostimulant-like functional nutrients are very important for the development of functional aquafeeds, I hope findings of this paper will help to develop low fishmeal based functional aquafeeds in near future.

A 56- day feeding trial was carried out to determine effects of purified nucleotide mixture for red sea bream ( Pagrus major ). Five dietary level of purified nucleotide mixture containing equal portion of inosine 5′ monophosphate (IMP), adenosine 5′ monophosphate (AMP), guanosine 5′ monophosphate (GMP), uridine 5′ monophosphate (UMP) and cytidine 5′ monophosphate (CMP) were supplemented to the basal diet (control, D1) at 0.5 (D2), 1.0 (D3), 1.5 (D4), 2.0 (D5) and 2.5 (D6) g kg − 1 . Triplicate groups of fish (initial weight: 2.6 g) were stocked in 100-L polycarbonate circular tanks at a density of 18 fish per tank under the flow-through system, and were fed the respective test diets twice daily to satiation level. After feeding trial, significantly higher growth performances, survival (%) and feed utilization were observed in fish fed with 1.5% mixed nucleotide supplemented diet (D4). Growth performance parameters were not differed significantly among diet groups D3 and D4. Feed conversion ratio, protein efficiency ratio and survival were not differed among diets D2 to D5. All the growth and feed utilization parameters were significantly lower in D1 and D6. In case of oxidative stress parameters fish fed nucleotide supplemented diets showed best condition because of the least oxidative stressed condition as well as the highest tolerance against oxidation. Stress resistance against low salinity exposure (LT 50 ), significantly increased with nucleotide supplementation and was highest in D4. Total serum protein, serum lysozyme activity and total peroxidase content tended to be higher (P > 0.05) in nucleotide supplemented group. Catalase activity reduced (P − 1 mixed nucleotides to promote growth, immune responses and stress resistance of juvenile red sea bream.

A 60 days feeding trial was conducted to evaluate the effects of dietary copper nanoparticles (Cu-NPs) or copper sulfate (CuSO 4 ) on growth performance, blood biochemical profiles, antioxidant status and immune response of red sea bream ( Pagrus major ) (initial body weight: 3.30 ± 0.02 g). Six diets were formulated containing CuSO 4 or 2, 4, 6 or 8 mg supplemental Cu as NPs were supplied to the basal diet (control). The obtained results showed that, fish fed diets supplemented with Cu-NPs at levels of 2 and 4 mg kg − 1 had the highest values of final body weight, weight gain, specific growth rate, feed intake, protein gain and tolerance against low-salinity stress. Significantly higher feed efficiency ratio, protein efficiency ratio, protein retention, whole body Cu content, protease activity, lysozyme activity and total serum protein were found at levels of 2 mg Cu-NPs kg − 1 diet when compared with the control group. Whole body protein of fish fed diet Cu-free diet was significantly lower than those of fish fed other diets. Fish fed diets supplemented with Cu-NPs at different levels gave the lowest values of plasma glucose. Furthermore, fish fed diets supplemented with Cu-NPs at 2 and 4 mg kg − 1 diet were in better conditions whereas, fish fed control diet implied comparatively higher oxidative conditions. Therefore, the data of the present study recommend adding 2 mg Cu-NPs per kg diet to improve fish growth, immune response and antioxidant defense system. Statement of relevance Efficiency of copper for red sea bream.

A feeding trial was conducted to utilize canola meal and soybean meal as major dietary protein sources for kuruma shrimp, Marsupenaeus japonicus. Four isocaloric diets (19 kJ g − 1 ) were formulated by reducing 0 (FM40), 70 (FM12), 85 (FM6) and 100% (FM0) of dietary fishmeal with a combination (4:6) of canola meal and soybean meal (blend). Based on a series of previous studies, all the plant protein diets (FM12, FM6 and FM0) were supplemented with 1.00% lysine, 0.50% methionine, 0.04% phytase and varying levels of fish soluble to improve the nutritional quality of the diets. Fifteen shrimp with an initial average weight of 1.74 g were randomly stocked in 12, 54 l rectangular tanks in triplicate per dietary treatments. The shrimp were given the respective test diets daily by hand at 8–10% of body weight for 60 days. Final body weight (g) and specific growth rate (% day − 1 ) were not significantly ( P > 0.05) affected by reducing fishmeal with plant protein blend. Feed intake was also not varied among the dietary treatments. On the other hand, feed conversion ratio was significantly ( P − 1 ) and protein retention (%) were significantly decreased in the FM0 group. Dietary treatments had no negative effects ( P > 0.05) on the whole body composition. Significant effect was also not found on the protease activity (unit mg − 1 protein) in the digestive tract of shrimp fed the FM40, FM12 and FM6 diets, while the value was significantly decreased in shrimp fed the FM0 diet. The values for the total hemocyte count (cells ml − 1 ) and viable cells (%) were lowest in the FM0 group, however these parameters were not significantly varied among the dietary treatments. Upon considering the results obtained in the present experimental condition, it has been concluded that canola meal and soybean meal could be effectively utilized as major protein sources by kuruma shrimp. The dietary fishmeal could be reduced to only 6% (85% replacement) with a blend of canola meal and soybean meal, and supplementation of methionine, lysine, phytase and fish soluble without compromising growth, feed utilization, body composition and health of juvenile kuruma shrimp. Statement of relevance The research findings will help to develop plant protein based diets for crustaceans.

Kawakawa tuna (Euthynnus affinis) is a novel target species for aquaculture in Japan and currently there is very limited knowledge on its early ontogenetic development in captivity. The ontogeny of E. affinis larvae from hatching to 20 days after hatching (DAH) was illustrated in the present study through an integrated approach of histology, biochemistry and molecular approaches. Larvae were fed enriched L-type rotifer Brachionus plicatilis species complex from 2 to 10 DAH, followed by enriched Artemia nauplii. Target digestive enzymes; trypsin, pepsin, lipase and amylase were assessed in order to evaluate nutritional condition. The larvae began exogenous feeding from 2 DAH, coinciding with the opening of the oral capacity and anus. The yolk sac was rapidly consumed and completely resorbed at 3 DAH, while the oil globule disappeared by 5 DAH. Enzymatic activity and expression of the target enzymes were detectable at hatching, except pepsin. With the development of the gastric glands, pepsin activity was then detected at 10 DAH, which was followed by rapid increase in pepsin activity at 15 DAH. The larvae showed rapid growth, however, high mortality also occurred at 6–10 DAH which has been highlighted as a critical stage in the larviculture of E. affinis. From 15 to 20 DAH, the histological structures of the digestive tract were completely segmented with the digestive tract resembling that of its juvenile stages. The activity of trypsin, pepsin, and lipase tended to increase sharply, while amylase dramatically dropped, possibly indicating a change in dietary preference. Findings from the present study provides a preliminary insight into the early development of the digestive system and associated digestive enzymes of E. affinis larvae and establishes an initial step towards the rearing and feeding protocol optimization of this novel target species.

The microalga Nannochloropsis oculata is used as a diet for rotifers and can enrich the highly unsaturated fatty acid (HUFA) proportion of rotifer polar lipids (PL-HUFA). For efficient enrichment of PL-HUFAs in rotifers, we evaluated nutrient–sufficient or –deficient cell populations to clarify when the alga should be harvested and fed to rotifers. The nutrient conditions for N. oculata were spectrophotometrically monitored during cultivation and cells with nutrient sufficiency (NS) and phosphorous deficiency (PD) were harvested. The PD cells exhibited reduced chlorophyll a content, photosynthetic activity, and growth rate and accumulated total lipids as non-polar lipids (NLs). A decrease in the proportion of HUFA to total lipids between two nutrient states corresponded to a similar phenomenon observed in NLs. On the other hand, PLs, including glycolipids and phospholipids, showed different trends. Glycolipids did not change fatty acid composition between two states. Phospholipids, however, showed significantly higher contents of arachidonic acid (ArA) and eicosapentaenoic acid (EPA) only in the early periods of PD culture. It was concluded that phosphorous deficiency stimulated cells to increase the fatty acid desaturation rate of non-plastidial membranes. Mitochondria in the PD cells decreased in number but increased in size and mass. Such adaptation of mitochondria can be associated with high desaturation of non-plastidial membranes. When the early P–limited phase culture was used for the enrichment of rotifers, PL-ArA and EPA of the rotifers were enhanced by twice as much as those fed on NS cells. This study provides evidence that the beginning of phosphorous deficiency is the optimum time to harvest N. oculata cells for enhancing rotifer PL-HUFAs.

We assessed the effects of fishmeal (FM) replacement by soy protein concentrate (SPC) with inosine monophosphate (IMP) supplementation on growth, digestibility, immunity, blood health, and stress resistance of red sea bream, Pagrus major. FM protein of a FM-based control diet (FM100) was replaced with 25 (FM75), 50 (FM50), 75 (FM25), and 100% (FM0) by SPC protein, and each replacement group was supplemented with 0.4% IMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (4.8 g) for 56 days. Results demonstrated that fish fed diet groups FM50 and FM75 had significantly the highest final weight, weight gain, specific growth rate, and feed intake. Meanwhile, in comparison to the control, growth performance and feed utilization did not significantly differ with the 75% FM-replaced diet group by SPC with IMP supplementation. Apparent digestibility coefficient of dry matter, protein, and lipid also followed a similar trend. All growth, feed utilization, and digestibility parameters were significantly lower in the FM0 diet group. Triglyceride level was increased (P

The effects of dietary administration of Bacillus subtilis on the growth, digestive enzyme activity, blood chemistry, oxidative status and immune response of red sea bream (Pagrus major) were evaluated in the current study. Fish fed five different levels of B. subtilis at 0 (BS0), 1 × 104 (BS1), 1 × 106 (BS2), 1 × 108 (BS3) and 1 × 1010 (BS4) CFU kg-1 diet for 60 days. The obtained results showed that B. subtilis supplementation significantly improved growth performance (FBW, WG and SGR), feed utilization (FI, FCE, PER and PG) and whole-body protein content when compared to the control group (P 0.05). Serum lysozyme activity exhibited higher values in case of BS3 and BS4 groups than BS0 group (P < 0.05), while mucus lysozyme activity increased only in BS3 group. Also, serum peroxidase activity enhanced significantly in fish fed BS2 and BS3 diets (P < 0.05), however, no activities were observed in the collected mucus. All groups reflexed high tolerance ability against oxidative stress except for BS0 and BS1 groups. Additionally, catalase activity increased significantly in all B. subtilis fed groups when compared to BS0 group (P < 0.05). Considering the obtained results, the supplementation of B. subtilis in the diet of red sea bream at 1 × 108 and 1 × 1010 CFU kg-1 diet could improve the growth, feed utilization, health condition and immune response.

A 56-day feeding trial was conducted to evaluate the effects of supplemented diets with β-glucan (BG) at four levels [0 (D1), 250 (D2), 500 (D3) and 1000 (D4) mg BG kg−1] on red sea bream, Pagrus major. The obtained results revealed a significant increase (P

A feeding trial was carried out to determine effects of heat-killed Lactobacillus plantarum (HK-LP) for red sea bream ( Pagrus major ). Five dietary levels of a commercial product containing 20% HK-LP at 1, 10, 100, 1000, and 2000 mg kg − 1 diets were supplemented to the basal diet (control), respectively. Triplicate groups of fish (initial weight: 11 g) were stocked in 100-L polycarbonate circular tanks at a density of 12 fish per tank under the flow-through system, and were fed the respective test diets for 56 days. At the end of a feeding trial, the results showed that the fish fed the diet at 10, 100, 1000 and 2000 mg kg − 1 HK-LP significantly grew faster than control group. Similarly, significantly improved feed intake, feed efficiency ratio, protein retention, and apparent digestibility coefficients were also found at 1000 mg kg − 1 HK-LP group than those in HK-LP free group. Some parameters such as serum lysozyme activity, total serum protein, mucus secretion, and the tolerance against low salinity stress were improved in fish fed 1000 mg kg − 1 HK-LP compared to those in HK-LP free group. This study demonstrated that HK-LP enhanced non-specific immune defense system of red sea bream, providing them with higher resistance to the stress and better immune response.

A feeding trial was carried out to determine effects of dietary supplements of inactivated Pediococcus pentosaceus (PP) on growth, feed utilization and blood characteristics of red sea bream. Five diets containing different concentrations [0 (PP0), 1.6 × 1010 (PPI), 1.6 × 1011 (PPII), 1.6 × 1012 (PPIII) and 3.2 × 1012 (PPIV) cells g−1] of PP were fed to fish for 56 days. At the end of the feeding trial, the obtained results revealed a significant increase (P

Plant proteins are the most important alternatives to fishmeal in shrimp diets. However, there is a general trend of reducing feed intake and shrimp performance with dietary inclusion of high levels of plant proteins. Supplementation of feed additives could overcome the negative effects of high plant protein based diet. Therefore, an experiment was conducted to assess the effectiveness of different feed additives such as crystalline amino acids (CAA), phytase (PT) and fish soluble (FS) in enhancing the utilization of high levels of plant proteins in the diets of kuruma shrimp, Marsupenaeus japonicus . Six isocaloric diets (19 kJ g − 1 ) were formulated where diet 1 was 40% fishmeal based control diet (FM). Diets 2 to 6 were prepared as follows, by replacing 60% fishmeal protein with a plant protein blend (soybean meal and canola meal; 6:4) alone (PP); protein blend and 1.5% CAA (PAA); protein blend and 0.04% phytase (2000 FTU kg − 1 ) (PPT); protein blend and 10% FS (PFS); and protein blend and a mixture of CAA, phytase and FS (PMX) respectively. Triplicate groups of shrimp (1.75 ± 0.40 g; mean initial body weight ± SD) were stocked in 54–l rectangular tanks at a rate of 15 shrimp per tank. The tanks were maintained under natural light/dark regime in a flow-through sea water system. Shrimp were fed the respective test diets at a rate of 8–10% of the body weight daily for 56 days. At the end of the feeding trial, final body weight (g), weight gain (%) and specific growth rate (% day − 1 ) were significantly ( P − 1 ) and protein retention (%) were significantly decreased in PP and PPT groups. Whole body crude protein was significantly lowest in PP group and highest in PMX group. Protease activity (unit mg − 1 protein) in the digestive tract of shrimp was lowest in PP and PAA groups; and the values were comparable among the rest. Overall, the best results for most of the parameters were found in shrimp fed PMX diet. Based on the overall performance of shrimp, it can be concluded that CAA, PT and FS are effective supplements in high plant protein diets for juvenile kuruma shrimp. A mixture of these supplements in appropriate ratio could further reduce the fishmeal levels in shrimp diets.

A 56-day feeding trial was conducted to evaluate the effects of supplemented diets with heat-killedLactobacillus plantarum(HK-LP) with graded levels of soybean meal (SBM) on growth, digestibility, blood parameters, and immune response ofSeriola dumerili(initial weight, 25.05 ± 0.1 g). Seven isonitrogenous and isolipidic practical diets were formulated to contain 0%, 15%, 30%, and 45% SBM, and each SBM level was supplemented with HK-LP at 0.0 and 0.1%. Fish fed diet which contains 30% SBM with HK-LP grew significantly faster than the other groups with notable feed intake and protein retention. Further, protein gain, whole body protein content, protease activity, protein, and lipid digestibility were significantly increased for all fish groups except for fish fed diet which contains 45% SBM with or without HK-LP. Interestingly, lysozyme activity was significantly enhanced in fish fed diets that contain 15% and 30% SBM with HK-LP. Hematocrit, peroxidase, and bactericidal activities revealed a significant increase in 30% SBM with HK-LP group. In addition, fish fed diets which contain 0% and 30% SBM with HK-LP showed higher tolerance against low-salinity stress compared with other groups. In conclusion, the addition of HK-LP to amberjack diets appeared to improve SBM utilization, immune response, and stress resistance.

Both taurine and glutamine play important roles in growth performance, feed utilization and anti-oxidation status. Therefore, a 60-day feeding trial was conducted to determine the interactive effects of dietary taurine and glutamine on growth performance, feed utilization, blood parameters and oxidative status of juvenile Japanese flounder. No interactive effect is shown in the selected parameters except for glutamic-pyruvate transaminase (GPT) of Japanese flounder in this study. The growth parameters (final body weight, body weight gain and special growth rate) and feed intake were significantly affected by either taurine or glutamine, meanwhile, plasma glucose, glutamyl oxaloacetic transaminase (GOT), glutamic-pyruvate transaminase (GPT) and triglycerides of Japanese flounder were significantly dec,reased when fed with high level of dietary taurine (1.6 g free taurine of 100 g dry diet). The other blood parameters (hematocrit, hemoglobin, glucose, total protein, total cholesterol, total bilirubin and triglycerides) were not significantly altered by various diets. The muscle free taurine concentration of Japanese flounder directly reflected the dietary taurine level, which was not affected by dietary glutamine. Interestingly, fish fed with both high levels of taurine (1.6 g free taurine of 100 g dry diet) and glutamine (1.5 g free glutamine of 100 g dry diet) showed higher oxidation resistance, which indicated the important roles of taurine and glutamine in fish oxidative stress protection.

This study was carried out to investigate the interactive effects of dietary leucine and valine on the performances of two sizes Japanese flounder Paralichthys olivaceus . Two groups of fish with average initial weights of 0.43 ± 0.01 g and 41.2 ± 2.0 g (mean ± S.D.) were fed with diets containing two levels of leucine (1.6 and 5.0% of diet) with three levels of valine (1.2, 1.8 and 2.5% of diet, as a 2 × 3 experimental design) and the control diet for 56 days and 30 days, respectively. In trial 1, after the fish fed with test diets for 56 days, growth performance and nutrients utilization were evaluated. Interactive effects of leucine and valine were found on growth parameters (final body weight, body weight gain and special growth rate) of Japanese flounder. Not only antagonism was observed in high dietary Leu level groups but also the stimulative effect of increased dietary Val in low Leu level groups. Significant interaction was also found on feed conversion ratio of Japanese flounder fed with test diets, however, the fish whole body proximate compositions were not altered by the various diets. In trial 2, dietary Leu and Val dominated the plasma free Leu and free Val concentrations, but no antagonism was found. Interactions were also found on plasma LDH and GPT of test fish, and it was showed that for fish fed with high dietary Val level in low Leu (1.6% of diet) diet can protect the cells from oxidative stress.

A study was conducted to determine the interactive effects of vitamin C (VC) and E (VE) supplementation on growth, fatty acid composition and oxidative status of Japanese flounder juveniles. Fish (initial average body weight of 1.1 ± 0.1 g) in triplicate were fed five test diets for 60 days. Control diet contained fresh fish oil (FFO, 8.9 meq/kg) with 100 mg α-tocopherol (α-Toc) equivalents/kg of VE and 500 mg ascorbic acid (AsA) equivalents/kg of VC (FFO100E/500C). The other four diets contained oxidized fish oil (OFO, 167.8 meq/kg) with varying levels of VE (mg/kg) and VC (mg/kg) (OFO100E/500C, OFO200E/500C, OFO100E/1000C and OFO200E/1000C). Fish fed FFO100E/500C and OFO100E/500C had no differences in body weight gain (BWG). However, fish fed OFO200E/1000C diet had a significantly lower BWG than FFO100E/500C. Fish fed OFO200E/500C and OFO100E/1000C showed no differences in thiobarbituric acid-reactive substance values compared with FFO100E/500C. Increasing the levels of VC and VE supplementation increased liver AsA and α-Toc contents, respectively. Liver α-Toc content was significantly increased with incremental dietary VC levels, indicating a sparing effect of VC on liver α-Toc content of fish. Increasing the levels of dietary VC and VE supplementations decreased concentrations of 20:5n-3, 22:5n-3 and 22:6n-3 in fish liver. Fish fed OFO100E/500C and OFO200E/1000C diets showed higher oxidative stress condition than those fed FFO100E/500C. In conclusion, dietary VC and VE supplementation could maintain normal growth and health condition of juvenile Japanese flounder fed OFO. However, high doses of both vitamin supplements induced fish lipid peroxidation under oxidative stress condition.