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A 12-week feeding trial was conducted to evaluate the effects of deficiency of vitamin E (αtocopherol) on the optimal vitamin C (L-ascorbic acid, AA) requirement in diets for juvenile Olive flounder (Paralichthys olivaceus). Ten diets... more
A 12-week feeding trial was conducted to evaluate the effects of deficiency of vitamin E (αtocopherol) on the optimal vitamin C (L-ascorbic acid, AA) requirement in diets for juvenile Olive flounder (Paralichthys olivaceus). Ten diets were formulated to contain two dietary vitamin E levels of 0 (E0) and 200 (E200) mg dl-tocopheryl acetate (TA) and five graded levels (0, 100, 300, 1000 and 3000 mg/kg diet) of AA in the form of L-ascorbyl-2-monophosphate (AMP). Fish averaging 4.81±0.06 g (mean ±SD) were distributed randomly to each aquarium as a group of 25 fishes. Increasing vitamin C levels from 0 to 100 mg/kg diets had significantly improved survival, weight gain and feed efficiency of fish, being particularly evident with vitamin E deficient diet (E0). Broken-line regression analysis indicated that the optimum dietary vitamin C level could be 114.99 mg ascorbic acid (AA)/kg diet in vitamin E deficiency diets (E0) and of 92.16 mg AA/kg diet in vitamin E supplemented diets (E200). The results indicated that vitamin E deficiency could increase the optimum dietary vitamin C level in juvenile Olive flounder.
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Additives in aquafeed are nutritive/nonnutritive ingredients that are supplemented in small amounts (alone or in combination) for a specific purpose, such as to improve the quality of fish as a final product, to preserve the physical and... more
Additives in aquafeed are nutritive/nonnutritive ingredients that are supplemented in small amounts (alone or in combination) for a specific purpose, such as to improve the quality of fish as a final product, to preserve the physical and chemical quality of the diet, or to maintain the quality of the aquatic environment. Moreover, growing interest in raising fish in an antibiotic-free environment, driven by consumer interest in the quality and safety of seafood, has hastened the search for safe dietary immunostimulants as an alternative to antibiotics. However, the importance of these additives received little attention outside the purview of aquaculture researchers. This chapter reviews the use of substantially important and promising additives in aquafeed.
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A 12 weeks of feeding trial was conducted to evaluate the effects of different levels of dietary yellow loess as an antibiotic (oxytetracycline) replacer in rainbow trout, Oncorhynchus mykiss. Five experimental diets were formulated to... more
A 12 weeks of feeding trial was conducted to evaluate the effects of different levels of dietary yellow loess as an antibiotic (oxytetracycline) replacer in rainbow trout, Oncorhynchus mykiss. Five experimental diets were formulated to contain no antibiotics or yellow loess (control/CON), three graded levels of yellow loess 5 (YL5), 10 (YL10) and 20 g YL kg−1 diet (YL20) and oxytetracycline at 5 g OTC kg−1 diet. Forty-five fish averaging 39.4 ± 1.6 g (mean ± SD) were randomly distributed in to 15 aquaria. Triplicate groups of fish were fed one of the experimental diets at 1.5 ~ 1.9% of wet body weight per day. At the end of the feeding trial, average weight gain (WG) and specific growth rate (SGR) from fish fed CON diet were significantly lower than those from fish fed YL10, YL20 or OTC diets (P < 0.05). Lysozyme activity from fish fed YL20 was detected to be significantly higher than that from fish fed CON diet (P < 0.05). While, superoxide dismutase (SOD) activity from fish fed YL10 and YL20 was recorded to be significantly higher than that from fish fed CON diet (P < 0.05). Fourteen days of challenge test with bacteria A. salmonicida showed significantly lower survival rate for CON than those of fish fed other experimental diets. Therefore, these results indicated that dietary yellow loess at 10–20 g kg−1 could be a promising alternative of oxytetracycline in rainbow trout.
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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... more
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; SP1, 2 × 10(9) CFU kg(-1) diet), single-probiotics 2 (Bacillus licheniformis; SP2, 2 × 10(9) CFU kg(-1) diet), multi-probiotics 1 (Bacillus subtilis + Bacillus licheniformis; MP1, 2 × 10(9) CFU kg(-1) diet), multi-probiotics 2 (commercial probiotics; Bacillus subtills + Bacillus licheniformis + Paenibacillus polymyxa + Aspergillus oryzae + Saccharomyces cerevisiae; MP2, 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 SP1, MP1 and MP2 diets were significantly higher than those of fish fe...
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A 2×3 factorial design was employed to evaluate the effects of dietary vitamin C (l-ascorblyl-2-monophosphate, C2MP) levels on growth and tissue mercury (Hg) accumulations in juvenile olive flounder, Paralichthys olivaceus. Six... more
A 2×3 factorial design was employed to evaluate the effects of dietary vitamin C (l-ascorblyl-2-monophosphate, C2MP) levels on growth and tissue mercury (Hg) accumulations in juvenile olive flounder, Paralichthys olivaceus. Six experimental diets with two levels of mercuric chloride (0 or 20mg HgCl2/kg diet) and three levels of vitamin C (0, 100, or 200mg C2MP/kg diet) were added to the basal diet. At the end of 6 weeks feeding trial, in presence or absence of dietary Hg, fish body weight gain, specific growth rate, feed efficiency, protein efficiency ratio and whole body lipid content were increased in a dose-dependent manner as dietary vitamin C level increased in the diets. Interestingly, fish fed 100 or 200mg C2MP/kg diets showed significant interactive effects on reducing Hg content in kidney tissue. These results revealed that dietary vitamin C as 100 or 200mg C2MP/kg diet had protective effect against Hg accumulation in juvenile olive flounder.
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ABSTRACT
We conducted two feeding trials to investigate the optimal feeding frequency of juvenile Korean rockfish Sebastes schlegeli fed a commercial diet of expanded pellets containing 47.2% crude protein, 9.2% crude lipid, and 14.5% ash at two... more
We conducted two feeding trials to investigate the optimal feeding frequency of juvenile Korean rockfish Sebastes schlegeli fed a commercial diet of expanded pellets containing 47.2% crude protein, 9.2% crude lipid, and 14.5% ash at two different water temperatures. In the first experiment, triplicate groups of 20 fish with an average weight of 2 g were fed an equal amount of diet (5.97% based on body weight) at one of six feeding frequencies (2, 3, 4, 5, 7, or 9 meals/day) for four weeks at . After four weeks, we measured weight gain (WG), specific growth rate (SGR), feeding efficiency (FE), and protein efficiency ratio (PER). Fish fed diet five meals/day grew significantly better than those fed nine meals/day. The second experiment used identical experimental conditions and feeding regions, except the food ration was slightly less (5.92% based on body weight) and the water temperature was increased to . After four weeks, we again measured WG, SGR, FE and PER. Fish fed seven meals/...
Two feeding trials were conducted to investigate the effects of feeding rate and frequency on growth performance and body composition of juvenile Korean rockfish Sebastes schlegeli reared at . In the first trial, three replicate fish... more
Two feeding trials were conducted to investigate the effects of feeding rate and frequency on growth performance and body composition of juvenile Korean rockfish Sebastes schlegeli reared at . In the first trial, three replicate fish groups averaging were fed a commercial diet with one of seven different daily feeding rates: 1.00%, 2.00%, 2.50%, 2.75%, 3.00%, 3.25%, and satiation (3.34%) based on body weight (BW). After four weeks of feeding, fish fed the 3% diet showed significantly higher weight gain (WG) and feed efficiency (FE) than fish that received the other feeding rates. In the second trial, the optimum feeding frequency was evaluated with three replicate fish groups averaging . Fish were fed a commercial diet at 2.87% BW with six different daily feeding frequencies: 2, 3, 4, 5, 7, or 9 meals. After four weeks of feeding, WG, specific growth rate, FE, and protein efficiency rate in fish fed 3 meals were significantly higher than those of fish fed 7 or 9 meals . In both feed...
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ABSTRACT This study was conducted to investigate the use of corn starch (CS) as a replacer of seaweed powder (SWP) in the diets of juvenile abalone, Haliotis discus hannai. Six experimental diets were formulated with CS to replace SWP at... more
ABSTRACT This study was conducted to investigate the use of corn starch (CS) as a replacer of seaweed powder (SWP) in the diets of juvenile abalone, Haliotis discus hannai. Six experimental diets were formulated with CS to replace SWP at 0, 20, 40, 60, 80, and 100% (Con, CS20, CS40, CS60, CS80, and CS100, respectively). Abalones averaging 0.44 ± 0.01 g (mean ± SD) were distributed into 18 tanks, and fed one of the six experimental diets in triplicate for 10 wk. After the feeding trial, abalone fed CS100 had a lower weight gain (WG) and specific growth rate than abalone fed the other diets; however, there was no significant difference among abalone fed Con, CS20, CS40, CS60, and CS80. Abalone fed Con, CS20, and CS40 had a higher feed efficiency and protein efficiency ratio than abalone fed CS100 diet, although there were no significant differences among abalone fed Con, CS20, CS40, CS60, and CS80. Abalone fed CS100 had a lower whole-body crude lipid content than did abalone fed Con. Broken-line analysis for WG indicated that dietary SWP was successfully replaced by CS up to 74.8%. Based on growth performance, CS could replace more than 74.8% but less than 80% of SWP in juvenile abalone diets.
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ABSTRACT The present experiment was conducted to evaluate the efficacy of dietary fermented by-product of mushroom, Pleurotus ostreatus, (FBPM) as an additive in juvenile Amur catfish, Silurus asotus. Five diets were formulated to contain... more
ABSTRACT The present experiment was conducted to evaluate the efficacy of dietary fermented by-product of mushroom, Pleurotus ostreatus, (FBPM) as an additive in juvenile Amur catfish, Silurus asotus. Five diets were formulated to contain 0%, 0.1%, 0.2%, 0.4% and 0.8% (FBPM0, FBPM0.1, FBPM0.2, FBPM0.4 and FBPM0.8 respectively) of FBPM. Fifteen fish averaging 5.7 ± 0.1 g (Mean ± SD) were fed one of the five diets in triplicate groups at 3–4% of wet body weight/day for 8 weeks. Average weight gain (WG) and specific growth rate (SGR) of fish fed FBPM0.1 and FBPM0.2 diets were significantly higher than those of fish fed FBPM0. Hematocrit contents of fish fed FBPM0.2 were significantly higher than that of fish fed FBPM0. Lysozyme activity of fish fed FBPM0.1 was significantly higher than those of fish fed FBPM0, FBPM0.2, FBPM0.4 and FBPM0.8, while chemiluminescent (CL) responses of fish fed FBPM0.2 was significantly higher than those of fish fed FBPM0, FBPM0.1, FBPM0.4 and FBPM0.8. Broken line regression analysis of WG showed that optimum dietary FBPM levels based on WG could be 0.11%. Therefore, these results suggested that the optimum dietary inclusion level of mushroom, Pleurotus ostreatus by-product fermented using lactobacillus and yeast could be greater than 0.11% but less than 0.2% based on WG and immunological responses in Amur catfish, Silurus asotus without any adverse effects on serological characteristics and body composition.
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ABSTRACT A feeding trial was conducted to evaluate the effects of dietary vitamin C (L-ascorbic acid, AA) levels on tissue AA concentration, hematology, non-specific immune response and gonad histology in male broodstock Japanese eel. A... more
ABSTRACT A feeding trial was conducted to evaluate the effects of dietary vitamin C (L-ascorbic acid, AA) levels on tissue AA concentration, hematology, non-specific immune response and gonad histology in male broodstock Japanese eel. A basal commercial diet was used as a control, and four other diets were prepared by supplementing 200, 400, 800 or 1600 mg AA kg− 1 diet in the form of L-ascorbyl-2-monophosphate (AMP). The analyzed AA concentrations of the diets were 32, 206, 423, 840 and 1686 mg kg− 1 diet, respectively. Triplicate groups of fish (initial body weight, 360 g) were fed one of the test diets at a ratio of 2% body weight for 16 weeks. At the end of the feeding trial, AA concentration in liver, kidney, muscle and testes was increased significantly in a dose dependent manner by increment of dietary AA level (P &lt; 0.05). Significantly higher hematocrit value was found in fish fed 1686 mg AA kg− 1 diet compared to 32 and 423 mg AA kg− 1 diets. White blood cells count of fish fed 1686 mg AA kg− 1 diet was significantly higher than those of fish fed 32–206 mg AA kg− 1 diet. Plasma glucose concentration was increased significantly with increasing dietary AA levels up to 840 mg AA kg− 1 diet; also significant enhancements in aspartate aminotransferase and alanine aminotransferase values were obtained at 1686 mg AA kg− 1 diet. Significantly higher superoxide dismutase activity was recorded in fish fed 840–1686 mg AA kg− 1 diet compared to 32–206 mg AA kg− 1 diet. The results of gonad histology showed an enhanced number of spermatogonia by dietary AA increment. The optimal dietary AA requirement level was estimated at approximately 410.8 and 911.8 mg AA kg− 1 diet by broken-line regression analysis based on liver and testes AA concentration, respectively.