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An 8-week feeding trial was conducted to evaluate the effects of dietary γ-aminobutyric acid (GABA) on growth performance, immune response, and disease resistance for juvenile whiteleg shrimp, Litopenaeus vannamei. Five isonitrogenous diets were formulated by supplementing 0 (CON), 50 (GABA50), 100 (GABA100), and 300 (GABA300) mg of GABA and 4 g of oxytetracycline (OTC) per kilogram of diet. A total of 225 juvenile whiteleg shrimp with an initial weight of 2.97 ± 0.06 g were randomly distributed and reared in 15 aquaria as triplicates. After 8 weeks of the feeding trial, weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of shrimp fed GABA100 were significantly higher than those of shrimp fed CON, GABA50, and GABA300 diets ( P < 0.05 ). However, there were no significant differences among shrimp fed CON, GABA50, GABA300, and OTC diets ( P > 0.05 ). After nine days of challenge test with Vibrio alginolyticus, the average cumulative survival rate of shrimp fed GABA50, GABA100, and OTC was significantly higher than that of shrimp fed GABA300 and CON diets ( P < 0.05 ). These results may suggest that 100 mg dietary GABA supplementation (including endogenous GABA, 175.6 mg/kg diet) per kilogram of diet could be the optimum dietary level to replace antibiotics and improve growth performance and disease resistance in whiteleg shrimp L. vannamei.

Olive flounder (Paralichthys olivaceus) also referred to as bastard halibut is a marine carnivorous species with great commercial value. The production of olive flounder has been dominated by aquac...

This study examined the effects of feeding fermented tuna by-product (FTBP) on the growth, non-specific immune response, liver and intestinal morphology, and disease resistance of olive flounder Paralichthys olivaceus. Olive flounders (n = 20; 2 g) were randomly assigned into four dietary groups in triplicates. Fish were fed four test diets (50% crude protein; 10% crude lipid) for 10 weeks in which unprocessed tuna by-product (TBP) meal was replaced (on a protein basis) with 0% (FTBP0 as the control diet), 15% (FTBP15), 30% (FTBP30), and 60% (FTBP60) of FTBP protein. Results showed that growth performance, blood parameters, and proximate composition were not influenced by FTBP inclusion. Non-specific immune parameters such as superoxide dismutase activity in the FTBP30 and FTBP60 groups were significantly higher than in the FTBP15 and the control groups, whereas lysozyme and myeloperoxidase activities were not different. Liver histopathology revealed normal architecture in groups fed FTBP0 and FTBP15 diets although mild alterations were noted in the FTBP30- and FTBP60-fed groups. Intestinal villi height and muscular thickness were not significantly altered with FTBP inclusion. Moreover, higher cumulative survival rate was observed in the FTBP60-fed group than fish fed with the other diets following the 13-day challenge with E. tarda. Together, these results demonstrate that fermented tuna by-product meal could be included at 60% in olive flounder diets.

Recent research is increasingly shedding light on the important role that microbial metabolites such as γ-aminobutyric acid (GABA) play in the context of nutrition, cognition, immune function, and the modulation of the gut microbiome. Yet, very few trials were conducted to assess the effects of its supplementation on biomarkers of fish health. Therefore, an eight-week feeding trial was devised to evaluate GABA supplementation in juvenile olive flounder, (

Background Bioprocessing of plant feedstuff can be a novel approach for reducing the overwhelming dependence on fish meal in aquaculture. The objective of this study was to evaluate the performance of Pacific white shrimp Litopenaeus vannamei fed solid-state fermented protein concentrates in order to replace fish meal in the diet. Results In the first trial, a group of 15 shrimp (average 3.88 g) were randomly distributed into aquaria in triplicate according to the experimental diets. Ten isonitrogenous (400 g kg-1 CP) and isolipidic (90 g kg-1 CL) diets were formulated to contain high-protein fish meal (HFM) and low-protein fish meal (LFM), and four types of bioprocessed protein concentrates (BPCs) as a replacement of fish meal (BPC-A, -B, -C and -D) each at 30% and 50% FM replacement levels. BPC-A was a solid-state fermented mixture of soybean and corn gluten meals; BPC-B was pre-treated acid-hydrolyzed BPC-A; BPC-C and BPC-D were BPC-A + 2% shrimp soluble extract (SSE) and BPC-B + 2% SSE, respectively. After 8 weeks, shrimp fed the HFM, BPC-B, BPC-C and BPC-D diets showed significantly higher growth performance at 30% FM replacement than those of shrimp fed the BPC diets at 50% FM replacement. Interestingly, shrimp fed the BPC-D diet could replace up to 50% FM replacement. In the second trial, the results show that apparent digestibility coefficients of feeds and apparent digestibility coefficients of ingredients for crude protein were significantly higher in fish fed the BPC-B, BPC-C and BPC-D diets. Conclusions The results demonstrated successful partial replacement of high-protein fish meal using high-quality fermented protein concentrates from plant sources. © 2019 Society of Chemical Industry.

An eight‐week feeding trial was conducted to evaluate the contribution of biofloc on dietary lipid requirement in whiteleg shrimp Litopenaeus vannamei. Five diets with graded levels of dietary lipid (45, 60, 90, 120 and 150 g/kg) were fed to juvenile shrimp. Final weight, weight gain and specific growth rate of shrimp fed diets with 60, 90 and 120 g/kg lipid levels were significantly higher than those of shrimp fed diets with lipid levels 45 and 150 g/kg (p

This study evaluated the effects of replacing fish oil (FO) with beef tallow (BT) in juvenile olive flounder, Paralichthys olivaceus (3.93 ± 0.07 g), over 8 weeks. Seven diets, consisting of 0, 25, 50, 75, and 100% replacement of FO with BT and 63 and 75.9% replacement supplemented with docosahexaenoic acid (DHA) at 0.9 and 1.1% of 100 g diet, respectively, were distributed into 21 tanks in a semi‐recirculation system with 15 fish per tank. The replacement of FO with BT at the given levels showed no significant changes (p > .05) in growth performance and whole‐body proximate composition. Fish fed the diet of 75.9% replacement with 1.1% DHA supplementation showed the best performance in these measurements among the treatments. Plasma glutamic pyruvic transaminase, cholesterol, high‐ and low‐density lipoproteins, and total protein were not significantly influenced by the replacement of FO with BT. The FO replacement generally resulted in a reduction of eicosapentaenoic acid, DHA, and n‐3/n‐6 polyunsaturated fatty acid ratio in the whole body, whereas the DHA supplementation recovered the level of DHA and the n‐3/n‐6 ratio to those observed in the group fed the 0% replacement diet. Taken together, BT along with DHA supplementation can potentially be a cost‐effective alternative for FO in olive flounder culture.

A 12‐week feeding trial was conducted to investigate the effects of two dietary probiotics; Bacillus subtilis KCTC 2217 or Bacillus licheniformis KCCM 11775 with two prebiotics; mannan oligosaccharide (MOS) or fructooligosaccharide (FOS) in Japanese eel. Fish averaging 12.8 ± 0.47 g (mean ± SD) were randomly distributed into five treatments with triplicate tanks. A basal control diet (CON) and four synbiotic diets supplementing B. subtilis + MOS (BSM), B. subtilis + FOS (BSF), B. licheniformis + MOS (BLM), and B. licheniformis + FOS (BLF). Weight gain and specific growth rate of fish fed all synbiotic diets were higher than those of fish fed CON. Immune‐related gene expression of heat shock protein 70 and immunoglobulin M of fish fed BSF and BLM were significantly higher than those of fish fed CON. Fish fed BSF and BLM had significantly higher intestinal villi length than those of fish fed BLF and CON (p

An eight‐week study was conducted to determine the optimum dietary choline level in juvenile olive flounder, Paralichthys olivaceus. Seven diets were prepared to contain 0, 250, 500, 750, 1,000, 2,000 and 3,000 mg/kg diet. Juveniles (5.9 ± 0.03 g; 5.5 ± 0.4 cm; mean ± SD) were randomly distributed into 21 tanks (25 fish/tank) and fed one of the diets in triplicates. Survival rate of fish fed the diet containing the lowest choline level was significantly lower than those of fish fed the other diets (p

s The present study was conducted to evaluate the effects of different dietary gamma-aminobutyric acid (GABA) levels in Nile tilapia, Orechromis niloticus. Six groups of fish averaging 3.03 ± 0.07 g (mean ± SD) were randomly distributed in 18 rectangular tanks in triplicates. A basal diet without GABA supplementation was used as a control (CON), and the other five diets were prepared by adding 75 mg GABA (GABA144), 75 mg GABA +50 mg heat-killed Lactobacillus paracasei (GABA189L), 150 mg GABA (GABA197), 150 mg GABA +50 mg heat-killed Lactobacillus paracasei (GABA242L), and 600 mg GABA (GABA507) per kg of diet. Actual GABA compositions for CON, GABA144, GABA189L, GABA197, GABA242L and GABA507 diets were 96, 144, 189, 197, 242 and 507 mg kg−1, respectively. After 8 weeks of experiment, weight gain, specific growth rate, feed efficiency and protein efficiency ratio of fish fed GABA189L were significantly higher than those of fish fed CON and GABA5.7 diets (P

Aquaculture has experienced tremendous growth over the last few decades as global production has increased from 16 million tons in 1990 to 110 million tons in 2016. Meanwhile, the modern aquacultur...

Five experimental diets were formulated to evaluate the effects of dietary enzymatically hydrolyzed tuna by-product on growth, non-specific immune responses, and hematology of juvenile rainbow trout (Oncorhynchus mykiss). A basal diet with 50% of fishmeal was used as control (CON) and four other diets replaced 12.5% (TBB12.5), 25% (TBB25), 37.5% (TBB37.5), and 50% (TBB50) of fish meal in the CON diet. Juvenile rainbow trout (4.87 ± 0.05 g) were randomly distributed into 15 tanks (50 L) and fed 3–4% of wet body weight two times a day. At the end of 7 weeks of feeding trial, weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of fish fed CON diet were significantly higher than those of fish fed TB50 diet (P 0.05). There were no significant differences in GPT levels among fish fed CON, TBB12.5, TBB25, and TBB37.5 diets. Also, there were no significant differences in lysozyme, superoxide dismutase, glucose, and total protein levels in all experimental diet (P > 0.05). The broken-line analysis indicated that the minimum dietary level of enzymatically hydrolyzed tuna by-product to replace fishmeal could be 29.7% in rainbow trout. These results indicated that the optimum level of dietary enzymatically hydrolyzed tuna by-product could replace greater than 29.7% but less than 37.5% of fishmeal in juvenile rainbow trout diet.

Background High demand and low supply of fishmeal due to overexploitation of fisheries resources have resulted in a dramatic increase in the price of this ingredient. Olive flounder (Paralichthys olivaceus) commercial feed contains approximately 60% fishmeal and limited success has been achieved in identifying sustainable alternative protein sources for this species. Methods An on-farm feeding trial was conducted to compare a basal diet containing 65% as the control (CONT) with two experimental diets replacing 10% of fishmeal by animal protein (AP10) or 20% of fishmeal by animal and plant protein (APP20). Sub-adult olive flounder averaging 327 ± 9.3 g (mean±SD) were fed one of the three diets in triplicate groups for 16 weeks. Results Weight gain, specific growth rate, feed efficiency, protein efficiency ratio, and survival were not significantly different among fish fed all the experimental diets (P > 0.05). Also, non-specific immune responses (superoxide dismutase and lysozyme activity), serum biochemical parameters, and intestinal villi length were not significantly different among fish fed all the experimental diets (P > 0.05). Conclusions Therefore, based on growth performance, non-specific immune responses, serum biochemical parameters, and intestinal histology, dietary animal and plant protein mixtures could replace up to 20% of fishmeal in the diet of sub-adult olive flounder.

An eight-week feeding trial was conducted to evaluate the effects of different dietary probiotic supplements in juvenile whiteleg shrimp, Litopenaeus vannamei. A basal control diet without probiotics (CON), and five other diets by supplementing Bacillus subtilis at 107 CFU/g diet (BS7), B. subtilis (BS8), Pediococcus pentosaceus (PP8), and Lactococcus lactis (LL8) at 108 CFU/g diet, and oxytetracycline (OTC) at 4 g/kg diet were used. Whiteleg shrimp with initial body weights of 1.41 &plusmn, 0.05 g (mean &plusmn, SD) were fed with these diets. Growth of shrimp fed BS8 and LL8 diets was significantly higher than those of shrimp fed the CON diet (p &lt, 0.05). Superoxide dismutase activity in shrimp fed PP8 and LL8 diets was significantly higher than that of shrimp fed the CON diet (p &lt, 0.05). Lysozyme activity of shrimp fed probiotics and OTC diets significantly improved compared to those on the CON diet (p &lt, 0.05). The intestinal histology showed healthier guts for shrimp fed the probiotic diets (p &lt, 0.05). Immune-related gene expression in shrimp fed BS8, PP8 and LL8 diets was recorded as significantly higher than that of shrimp fed CON and OTC diets (p &lt, 0.05). Also, results of the challenge test for 7 days and the digestive enzyme activity of shrimp fed BS8, PP8, and LL8 were significantly improved compared to those on the CON diet (p &lt, 0.05). Therefore, these results indicated that L. lactis at 108 CFU/g could be an ideal probiotic for whiteleg shrimp, and also B. subtilis WB60 and P. pentosaceus at 108 CFU/g could improve the growth, immunity, histology, gene expression, digestive enzyme activity, and disease resistance, while replacing antibiotics.

An eight-week feeding trial was conducted to evaluate the effects of a basal control diet (CON), Bacillus subtilis at 107 (BS7) and at 108 CFU/g diet (BS8), Lactococcus lactis at 107 CFU/g (LL7) and at 108 CFU/g diet (LL8), and oxytetracycline (OTC) at 4 g/kg diet on Nile tilapia. Fish with initial body weight of 2.83 &plusmn, 0.05 g (mean &plusmn, SD) were fed two times a day. Weight gain, specific growth rate, feed efficiency, protein efficiency ratio and lysozyme activity of fish fed BS8, LL8 and LL7 diets were significantly higher than those of fish fed CON diet (p &lt, 0.05). Superoxide dismutase and myeloperoxidase activity of fish fed BS8, LL8, BS7, LL7 and OTC diets were significantly higher than those of fish fed CON diet. Intestinal villi length and muscular layer thickness of fish fed BS8, LL8 and LL7 diets were significantly higher than those of fish fed CON and OTC diets. Also, heat shock protein 70 (HSP70), interleukin (IL-1&beta, ), interferon-gamma (IFN-&gamma, ) and tumour necrosis factor (TNF-&alpha, ) gene expression of fish fed BS8 and LL8 diets were significantly higher than those of fish fed CON diet. After 13 days of challenge test, cumulative survival rate of fish fed BS8 and LL8 diets were significantly higher than those of fish fed CON, BS7 and OTC diets. Based on these results, B. subtilis and L. lactis at 108 (CFU/g) could replace antibiotics, and have beneficial effects on growth, immunity, histology, gene expression, and disease resistance in Nile tilapia.

A 9-week feeding trial was conducted to evaluate the optimum dietary level of PROTIDE (PRO), a single-cell protein obtained from the bacteria Corynebacterium ammoniagenes, as a substitute for fish meal in the diet of whiteleg shrimp Litopenaeus vannamei. Five diets were formulated that replaced fish meal at 0% (PRO0), 10% (PRO2), 20% (PRO4), 30% (PRO6) and 40% (PRO8). Fifty shrimp averaging 0.15 ± 0.02 g (mean ± SD) body weight were randomly distributed between 20 experimental tanks and fed one of the five experimental diets. At the end of the experiment, final weight, weight gain, specific growth rate and feed conversion ratio of shrimp fed PRO0 and PRO2 diets were significantly improved compared to those fed PRO6 and PRO8 diets (P

We evaluated the effects of some dietary natural mineral materials as an antibiotic replacer based on growth performance, non-specific immune responses and disease resistance in juvenile and subadult rainbow trout, Oncorhynchus mykiss. First experiment, juvenile rainbow trout averaging 2.7 ± 0.02 g (mean ± SD) were fed one of the six experimental diets; a basal commercial diet as a control (CON), CON with oxytetracycline (OTC), with yellow loess (YL), with Macsumsuk® (MS), with Song-Gang® stone (SG) and with barley stone (BS) at 0.4% of each diet. At the end of 8-week feeding trial, weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) of fish fed YL diet were significantly higher than those of fish fed CON diet. Non-specific immune responses such as superoxide dismutase (SOD), myeloperoxidase (MPO), lysozyme (LYS) activity and oxidative radical production of fish fed YL diet were higher than those of fish fed CON diet. At the end of 15 days of challenge test with Aeromonas salmonicida, average cumulative survival rate of fish fed YL diet was significantly higher than that of fish fed BS and CON diets. However, there were no significant differences among fish fed YL, SG and OTC diets. Second experiment, subadult rainbow trout averaging 261.5 ± 3.5 g (mean ± SD) were fed one of the four experimental diets for 22 weeks: CON, and CON with OTC, YL or SG at 0.4% of each diet. At the end of feeding, growth performance of fish fed SG and YL diets was significantly higher than that of fish fed CON diet. Non-specific immune responses in terms of SOD, MPO, LYS and NBT of fish fed SG and YL diets were significantly higher than those of fish fed CON diet. However, there were no significant differences among the fish fed YL, SG and OTC diets. The results indicate that dietary yellow loess or Song-gang® stone at 0.4% of diet could replace oxytetracycline in juvenile and subadult rainbow trout.

A 10-week feeding trial was conducted to determine the effects of dietary yucca meal supplementation on growth, haematology, non-specific immune responses and disease resistance in juvenile Nile tilapia, Oreochromis niloticus. Six isonitrogenous and isoenergetic experimental diets were formulated to contain 0% (YMS0), 0.1% (YMS0.1), 0.3% (YMS0.3), 0.5% (YMS0.5), 1% (YMS1.0) and 2% (YMS2.0) dietary yucca meal on the dry weight basis. Results of this study showed a higher growth performance for YMS0.1 group with significant differences with YMS0.5, YMS1.0 and YMS2.0 groups. In addition, whole-body protein content of fish fed the YMS0.1 diet was significantly higher as compared to YMS0. Plasma lysozyme activity significantly increased in YMS0.1 group comparing to YMS0 and YMS0.5 groups. Respiratory burst activity of phagocytic blood cells was significantly enhanced when fish were fed the YMS0.1 diet. Results also showed that yucca meal supplementation had moderate effects on glutamic oxaloacetic transaminase and cholesterol levels. After the 14-day challenge test with Aeromonas hydrophila, cumulative survival of fish fed YMS0.1 diet was significantly higher than that of fish fed diet YMS0, YMS1.0 and YMS2.0. These results suggest that the optimum dietary yucca meal inclusion level in the diet of juvenile Nile tilapia could be between 0.1% and 0.14% (23.9~33.4 mg kg−1 saponin) as a feed additive to promote growth, enhance the non-specific immune responses and increase disease resistance.

A 10-weeks of feeding trial was conducted to evaluate the dietary selenium (Se) requirement and toxicity levels in juvenile Nile tilapia, Oreochromis niloticus using seleno-methionine as the source of Se. Graded level of Se-Met were added to the basal diet at 0, 0.25, 0.5, 0.75, 1.0, 2.0, 4.0, 8.0 and 16.0 mg Se/kg diet providing the analyzed Se of 0.30 (Se0.30), 0.55 (Se0.55), 0.73 (Se0.73), 0.82 (Se0.82), 1.04 (Se1.04), 2.06 (Se2.06), 2.95 (Se2.95), 6.31 (Se6.31) and 14.7 (Se14.7) mg Se/kg diet respectively. Twenty fish averaging 1.85 ± 0.1 g (mean ± SD) were fed one of the nine experimental diets in triplicate groups. At the end of the feeding trial, weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of fish fed Se2.06 were significantly higher than those of fish fed other diets (p 1.06 but Statement of relevance The importance of trace mineral, selenium (Se) supplementation in fish feed formulation has been well accepted since Se from ambient water and feed itself cannot supply the optimal level required by the cultured aquatic species. Even though, Se is typically required in much lower quantity in fish diet but its supplementation at optimum level is a critical issue in fish feed formulation. Scientific reports gathered over last two decades indicate, Se is quite sensitive and proper care should be taken to ensure their inclusion at optimum level in fish feed formulation. The present experiment clearly demonstrated that, freshwater fish juvenile Nile tilapia has a specific requirement level for dietary Se which cannot be met by regular feed and ambient water. Inclusion of dietary Se at optimum level is imperative to promote the maximum growth, tissue saturation and to ensure an optimum enzyme activity in Nile tilapia. Supplementing Se in fish feed beyond the requirement level may have toxic effects in freshwater aquaculture.

In an eight-week feeding trial, encapsulated sodium butyrate (ESB), gamma-aminobutyric acid (GAB), selenium-yeast (SeY), yeast extract nucleotides (YEN), yucca meal (YUM), song-gang stone (SGS) and protease (PRT) were evaluated as functional feed additives in a low fishmeal (FM) diet for olive flounder Paralichthys olivaceus. Eight experimental diets were fed to 5.26 ± 0.17 g (mean ± SD) juvenile olive flounder in triplicates. A low-FM basal diet without feed additive was considered as control (CON); seven other diets were prepared by adding 4 g ESB, 158 mg GAB, 2 g SeY, 4 g YEN, 1.5 g YUM, 4 g SGS, and 175 mg PRT per kg of basal diet. Weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of fish fed diets YEN, GAB, and SGS were significantly higher than those of fish fed CON diet (P .05). Heat shock protein 70 gene expression of fish fed YEN and SeY was significantly higher than those of fish fed the CON diet. Intestinal villi length of fish fed YEN, GAB, SGS, and ESB was significantly higher than those of fish fed CON. Also, intestinal trypsin activity of fish fed YEN, GAB, SGS, ESB, and PRT was significantly higher than those of fish fed CON diet (P

Six different types of solid state fermented plant proteins and soy protein concentrate were evaluated as fish meal replacers in whiteleg shrimp, Litopaeneus vannamei. In the first experiment, eight experimental diets consisted of a control diet without fish meal replacement (CON), and seven other diets replacing 30 % of fish meal with fermented soybean meal with Bacillus subtilis (FSMB), sterilized FSMB (FSMBS), fermented soybean meal and corn gluten meal with B. subtilis (FSCB), sterilized FSCB (FSCBS), fermented soy protein concentrate with B. subtilis (FSPB), fermented soybean meal with lactic acid bacteria (FSML), and soy protein concentrate (SPC). At the end of eight weeks, weight gain, specific growth rate and serum lysozyme activity of shrimp fed FSMB and FSCB diets were significantly higher than those of shrimp fed CON and FSML diets (P

A 12-week feeding trial was conducted to evaluate the synergistic effects of dietary vitamin E, α-Tocopheryl acetate (α-TA) and arachidonic acid, 20:4n-6 (ARA) on non-specific immune responses and tissue concentrations in female Japanese eel broodstock, Anguilla japonica. Four experimental diets (in a 2 × 2 factorial design) were formulated to contain two different levels of α-TA and ARA. A basal commercial diet without supplementation was used as the control (E0ARA0) with three other diets being formulated by addition of 200 mg α-TA kg−1 (E200ARA0), 5 mg ARA kg−1 (E0ARA5), and 200 mg α-TA + 5 mg ARA kg−1 (E200ARA5). Four triplicate groups of 10 fish averaging 279 ± 9.0 g (mean ± SD) were randomly assigned to twelve 150-L tanks with a constant flow rate of 4 L min−1. At the end of the trial superoxide dismutase (SOD) activity of fish fed E200ARA5 were significantly higher than those of fish fed E0ARA0 and E200ARA0 (P > .05). Myeloperoxidase (MPO) and Lysozyme activities showed a similar trend with SOD activity, though there were no significant differences among the activities of fish fed experimental diets (P

A 6-week feeding trial was carried out to evaluate the effects of dietary vitamin E (dl-α-tocopheryl acetate, TA) on growth and mercury (Hg) accumulation in juvenile olive flounder (Paralichthys olivaceus) treated with mercuric chloride (HgCl2). Vitamin E and HgCl2 were added to the semi-purified basal diet. Six semi-purified diets in a 2 × 3 factorial design were formulated to contain 2 levels of Hg (0 or 20 mg HgCl2/kg diet) and 3 levels of vitamin E (0, 100, or 200 mg TA/kg diet). Experimental fish (n = 360, 9.99 ± 0.15 g) were randomly allocated into 30-L tanks at a density of 20 fish per tank with 3 replicates in each treatment and were fed twice a day. At the end of the feeding trial, dietary Hg depressed the growth performances in terms of weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) in fish, while fish fed the diets supplemented with vitamin E showed significant growth improvement in both presence and absence of HgCl2 in the diets (P

The current experiment was conducted to evaluate and compare the efficacy of two different probiotics Bacillus subtilis WB60 and Lactobacillus plantarum KCTC3928 in diet of Japanese eel, Anguilla japonica. Seven experimental diets were formulated to contain no probiotics (CON), three graded levels of B. subtilis at 106 (BS1), 107 (BS2), 108 (BS3) and L. plantarum at 106 (LP1), 107 (LP2), 108 (LP3) CFU/g diet. Twenty fish averaging 8.29 ± 0.06 g were distributed in to 21 aquaria and were randomly assigned to one of the experimental diets in triplicate groups. Average weight gain (WG), feed efficiency (FE), and protein efficiency ratio (PER) of fish fed B. subtilis at 107 (BS2) and 108 (BS3) CFU/g diet were significantly higher than those of fish fed other experimental diets (P

An 8-week feeding trial was conducted to evaluate the effects of dietary probiotics on growth performance and non-specific immune responses in starry flounder, Platichthys stellatus . Fish averaging 46.5 ± 0.65 g (mean ± SD) were fed one of the six experimental diets; one control (Cont), and five other diets were prepared by supplementing single-probiotics 1 ( Bacillus subtilis ; SP 1 , 2 × 10 9 CFU kg −1 diet), single-probiotics 2 ( Bacillus licheniformis ; SP 2 , 2 × 10 9 CFU kg −1 diet), multi-probiotics 1 ( Bacillus subtilis + Bacillus licheniformis ; MP 1 , 2 × 10 9 CFU kg −1 diet), multi-probiotics 2 (commercial probiotics; Bacillus subtills + Bacillus licheniformis + Paenibacillus polymyxa + Aspergillus oryzae + Saccharomyces cerevisiae ; MP 2 , 2 × 10 9 CFU kg −1 diet) and oxytetracycline (OTC) at 5 g OTC kg −1 diet. At the end of 8 weeks feeding trial, weight gain (WG) and specific growth rate (SGR) of fish fed SP 1 , MP 1 and MP 2 diets were significantly higher than those of fish fed control diet (P 2 diet was significantly higher than those of fish fed OTC diet (P 1 , MP 1 and MP 2 diets were significantly higher than those of fish fed OTC diet (P 1 , SP 2 , MP 1 and MP 2 diets. During the Edwardsiella tarda challenge test, the first mortality occurred on day 2. After the 14 days challenge test, cumulative survival rate of fish fed MP 1 and MP 2 diets were significantly higher than those of fish fed control diet (P 1 , SP 2 , MP 1 , MP 2 and OTC diets in survival rate at the termination of the challenge test. Although there was little advantage in immunological parameters with fish fed MP diets, single and multi-probiotics were equally effective statistically. These results demonstrated that single or multi-probiotics had equal beneficial effect as an antibiotic replacer in terms of growth performance, non-specific immune responses and disease resistance in starry flounder.

Different levels of dietary soybean meal (SBM) as a fish meal (FM) replacer, with and without amino acid supplementation, for whiteleg shrimp, Litopenaeus vannamei reared in the biofloc system was examined in eight weeks of feeding trial. Eight experimental diets consisted of a basal diet with 0% FM replacement by SBM provided in clear sea water without biofloc system (S0SW), four diets replacing FM at 0% (S0), 33% (S33), 67% (S67) and 100% (S100) by SBM, and three diets replacing FM at 33% (S33A), 67% (S67A) and 100% (S100A) by SBM supplemented with amino acids (methionine and lysine) in the seawater biofloc system. Results of water quality analyses showed significantly lower total suspended solids and nitrate for S0SW group than all other treatments. Diets S0 and S33A resulted in higher weight gain and specific growth rate among all groups, with no significant differences with S33 group. In addition, whole-body protein and amino acid compositions of shrimp fed S0SW were lower than most biofloc groups. Haemolymph parameters showed significant differences in total protein, cholesterol and triglyceride between groups S0 and S0SW. Also, superoxide dismutase activity showed a decreasing trend with increasing replacement level. In conclusion, based on these results, SBM could replace up to 33% of FM with or without amino acid supplementation in juvenile whiteleg shrimp diets reared in the biofloc system.