Search

An 11-week feeding trial was conducted to study the effects of the different levels of dietary vitamin C on growth, tissue ascorbic acid concentrations and histopathological changes in parrot fish. Casein and gelatin-based diets were formulated to contain 0, 60, 120, 240, 480 and 2000 mg l-ascorbic acid (AA) per kg diets on AA equivalent basis in the form of l-ascorbyl-2-monophosphate (AMP), 60 and 240 mg AA per kg diet as l-ascorbic acid. However, the analyzed AA levels were 0, 50, 100, 205, 426 and 1869 mg AA per kg diet in AMP supplemented diets; 36 and 149 mg AA per kg diet in l-ascorbic acid supplemented diets. Thus, the diets were designated as AA-free, AMP50, AMP100, AMP205, AMP426, AMP1869, AA36 and AA149. Fish averaging 3.9±0.06 g (mean±S.D.) randomly were fed the experimental diets in triplicate groups for 11 weeks. Weight gain (WG) of fish fed AMP50 and AA36 diets were significantly lower than those of the other groups, and fish fed AMP1869 diet showed a higher WG than did fish fed AMP50, AMP100, AMP205, AA36 and AA149 diets (P

The study was conducted to investigate the effects of dietary Chlorella powder (C) supplementation on growth performance, blood characteristics, and whole-body composition in juvenile Japanese flounder Paralichthys olivaceus. Four experimental diets were supplemented with C at 0, 1, 2 and 4% (C0, C1, C2, and C4) on a dry-weight basis. Three replicate groups of fish averaging 1.13 ± 0.02 g (Mean ± SD) were randomly distributed in each aquarium and fed one of four experimental diets for 12 wk. After 12 wk of the feeding trial, fish fed C2 diet had higher weight gain (WG), feed efficiency (FE), and protein efficiency ratio (PER) than did fish fed C0 and C1 diets (P 0.05); however, there was no significant difference among fish fed C1 and C4 diets, and among fish fed C2 and C4 diets (P > 0.05). Fish fed C2 and C4 diets had a lower serum cholesterol level than did fish fed C0 and C1 diets (P 0.05). Fish fed C2 and C4 diets had a lower body fat than did fish fed C0 (P 0.05). These results indicate that dietary supplementation of 2%Chlorella powder in the commercial diets could improve growth, feed utilization, serum cholesterol level, and whole-body fat contents in juvenile Japanese flounder.

This experiment was conducted to determine the optimum dietary protein level for juvenile olive flounder Paralichthys olivaceus (Temminck et Schlegel) fed a white fish meal and casein-based diets for 8 weeks. Olive flounder with an initial body weight of 4.1 ± 0.02 g (mean ± SD) were fed one of the six isocaloric diets containing 35%, 45%, 50%, 55% and 65% crude protein (CP) at a feeding rate of 4–5% of wet body weight on a dry-matter basis to triplicate groups of 20 fish per aquarium. After 8 weeks of feeding, per cent weight gain (WG) and feed efficiency ratios of fish fed the 55% CP diet were not significantly higher than those from fish fed the 50% and 65% CP diets, but significantly higher than those from fish fed the 35% and 45% CP diets. Fish fed the 50%, 55% and 65% CP diets had significant higher specific growth rates than did fish fed the 35% and 45% CP diets; however, there was no significant difference among fish fed the 50%, 55% and 65% CP diets. The protein efficiency ratio was inversely related to the dietary protein level; that is, maximum efficiency occurred at the lowest dietary protein level. Broken-line model analysis indicated that the optimum dietary protein level was 51.2 ± 1.8% for maximum weight gain in juvenile olive flounder. The second-order polynomial regression analysis showed that the maximum WG occurred at 57.7% and it revealed that the minimum range of protein requirement was between 44.2% and 46.4%. These findings suggest that the optimum dietary protein level for maximum growth could be greater than 46.4%, but less than 51.2% CP in fish meal and casein-based diets containing 17.0 kJ g−1 energy for juvenile olive flounder.

This experiment was conducted to study the effects of different dietary levels of vitamin C, L-ascorbyl-2-polyphosphate (ASPP), on growth and tissue vitamin C concentrations in juvenile olive flounder, Paralichthys olivaceus (Temminck et Schlegel). Fish were fed one of six semi-purified diets containing an equivalent of 0, 25, 50, 75, 150, or 1500 mg ascorbic acid (AA) kg−1 diet (C0, C25, C50, C75, C150 or C1500) in the form of ASPP for 12 weeks. Weight gain (WG) and protein efficiency ratio (PER) of fish fed the C0 diet were significantly lower than those of fish fed the other diets (P

This experiment was conducted to reevaluate the optimum dietary protein level for the maximum growth of juvenile Korean rockfish, Sebastes schlegeli (Hilgendorf). Lyophilized rockfish muscle and casein were used as the major protein sources in the basal diet. After 1 week of the conditioning period, triplicate groups of 20 fish averaging 7.3 ± 0.04 g (mean ± SD) were fed one of five semipurified diets containing the graded levels of 35%, 40%, 45%, 50% or 60% crude protein (CP). After 8 weeks of the feeding trial, weight gain (WG) and specific growth rate (SGR) of fish fed 60% CP diet were significantly higher than those of fish fed 45%, 40% and 35% CP diets. There was no significant difference in WG and SGR between fish fed 60% and 50%, and between fish fed 50% and 45%. Fish fed 60%, 50% and 45% CP diets had a higher feed efficiency ratio (FER) than did fish fed 40% and 35% CP diets. There was no significant difference in FER between fish fed 40% and 35% CP diets, and among fish fed 60%, 50% and 45% CP diets. Protein efficiency ratio (PER) was inversely related to the dietary protein level in a linear fashion. Whole-body protein and fat content were negatively correlated, and ash content was not affected by varying dietary protein levels. Broken-line analysis indicated that the optimum dietary protein level could be 48.6% ± 3.45% (mean ± SD) for maximum WG in this study. Therefore, these findings suggest that the optimum dietary protein level for maximum growth could be equal to or greater than 48.6%, but less than 50% CP containing 16.7 kJ g−1 in juvenile Korean rockfish.

Two experiments were conducted to compare the patterns of plasma free amino acid concentrations after force-feeding in rainbow trout Oncorhynchus mykiss (Walbaum) with and without dorsal aorta cannulation. In the first experiment, 35 rainbow trout averaging 504 ± 7.8 g (mean ± SD) were divided into seven groups of five fish each. After 48 h starvation, a group of fish was anaesthetized and blood samples were taken at one of the following time periods: 0, 4, 8, 12, 24, 36 and 48 h after feeding. In the second experiment, five dorsal aorta cannulated rainbow trout averaging 511 ± 6.2 g (mean ± SD) were kept in a cage. After 48 h starvation, the fish were anaesthetized and blood samples were taken from the same fish at 0, 4, 8, 12, 24, 36 and 48 h after feeding. In the first experiment, the concentration of all plasma free amino acids except histidine and glycine peaked at 4 h and returned to the basal level 24 h after feeding. In the second experiment, the concentration of all plasma free amino acids except isoleucine, leucine, phenylalanine and tryptophan also peaked at 4 h and returned to the basal level 24 h after feeding. These results showed that the pattern of plasma free amino acid concentrations from fish with and without dorsal aorta cannulation were similar.

The present study was conducted to investigate the effects of Chlorella powder (CHP) as a feed additive on growth performance in juvenile Korean rockfish, Sebastes schlegeli (Hilgendorf). Six experimental diets were supplemented with Chlorella powder (CHP) at 0, 0.5, 1.0, 1.5, 2.0 and 4.0% (CHP0, CHP0.5, CHP1.0, CHP1.5, CHP2.0 and CHP4.0, respectively) of diet as a dry matter basis. Three replicate groups of fish averaging 2.1 ± 0.02 g (mean ± SD) were fed one of six experimental diets for 12 weeks. After the feeding trial, fish fed CHP0.5 had a higher weight gain and specific growth rate than did fish fed CHP0, CHP1.5, CHP2.0 and CHP4.0. However, there was no significant difference among fish fed CHP0.5 and CHP1.0. Fish fed CHP0.5 had a significantly higher feed efficiency ratio and a protein efficiency ratio than did fish fed the other diets. Fish fed CHP4.0 had a lower significantly serum total lipid than did fish fed CHP0, CHP0.5 and CHP1.0, however, there was no significant difference among fish fed CHP1.5, CHP2.0 and CHP4.0. Fish fed CHP2.0 had significantly higher serum albumin and lower serum glucose than did fish fed CHP0. Fish fed CHP4.0 had significantly higher liver protein and lower liver fat than did fish fed the other diets. These results suggest that the optimum dietary CHP supplementation level could be approximately 0.5% of diet for positive effects on growth and feed utilization without any negative effects on blood parameters and body composition in juvenile Korean rockfish.

A 6-week feeding trial was conducted to determine the apparent protein and phosphorus digestibilities in order to evaluate five different dietary protein sources in juvenile Korean rockfish, Sebastes schlegeli. Five diets containing fish meal analog (BAIFA-MTM), white fish meal (WFM), rockfish muscle (RM), soybean meal (SM) or corn gluten meal (CGM) were prepared by mixing a basal diet (BD) with one of five test ingredients at the ratio of 7:3. As a reference diet, BD contained three different protein sources, such as casein, gelatin and rockfish muscle. Fish averaging 3.1 ± 0.03 g (mean ± SD) were distributed to each aquarium as a group of 20 fish reared in the recirculating system. Fish of triplicate groups were fed one of six experimental diets (BD + five test diets). Apparent digestibilities of dry matter, protein and phosphorus of six diets were determined by the chromic oxide (Cr2O3) method. After 6 weeks of the feeding trial, apparent protein digestibilities of RM, WFM, CGM, SM and BAIFA-MTM were 92.6%, 87.5%, 79.1%, 76.2% and 70.6%. Apparent phosphorus digestibilities of RM, BAIFA-MTM, WFM, CGM and SM were 77.5%, 66.9%, 59.5%, 22.2% and 12.6%. The protein efficiency ratio (PER) ranked with RM > WFM, BD > BAIFA-MTM, CGM and SM (P

This experiment was conducted to estimate the dietary protein requirement of larval Japanese flounder Paralichthys olivaceus (also known as the olive flounder) and to examine the effects of a commercial diet and three experimentally developed microparticulate diets (MPDs) on their growth and body composition. Larvae were fed four MPDs for 75 d beginning 8 d after hatching (DAH); fish in these experimental diets were also concurrently fed live feeds until 45 DAH, as is the normal procedure in commercial hatcheries. One MPD was a commercial diet (CD) of marine fish in which crude protein ranged from 55.8% to 61.2% (dry weight basis; varied with pellet size); the three laboratory-prepared diets based on Japanese flounder muscle contained either 40% (D40), 50% (D50), or 60% (D60) crude protein. At 83 DAH, body weights and lengths of fish fed diet D60 were not significantly different from those fed diet CD. Fish fed diet CD had significantly greater body weights and lengths than those fed diets D40 an...

A mixture of animal by-products (MAB) was tested to replace fish meal (FM) in diets for juvenile rainbow trout Oncorhynchus mykiss. Fish averaging (±SD) 0.96 ± 0.07 g were divided into 15 groups, and 3 groups were fed one of five isonitrogenous diets replacing 0, 20, 40, 60, or 100% of FM protein with similar percentages of MAB (control, MAB20, MAB40, MAB60, or MAB100, respectively). The MAB consisted of 25% meat and bone meal, 24.5% leather meal, 20% squid liver powder, 15% feather meal, 7.5% blood meal (spray-dried), 7.5% poultry by-product meal, and 0.25% each methionine and lysine. After 16 weeks of feeding, fish fed diets MAB40, MAB60, and MAB100 exhibited significantly lower growth performance than the fish fed the control and MAB20 diets. Apparent digestibility estimates of protein with different collection times (every 40 min and after 12 and 48 h) did not show, in a feces collection system, protein leaching into the water for up to 48 h. The MAB substitution of up to 60% of FM protein in...

Intensive tank rearing of channel catfish (Ictalurus punctatus Rafinesque) fry can be successfully accomplished with commonly available ‘salmonid’ starter diets. Ingredient substitution in starter diets is less important from the cost perspective but growth, survival and health of fish are major concerns. Several combinations of fish meals and animal protein substitutes were evaluated in diet formulations for hatchery rearing of catfish fry. Sub-optimal thermal conditions were used which are characteristic for the north-central USA where catfish culture is important for stocking purposes and live-fish markets. A diet formulated on the basis of menhaden fish meal (29.1%), herring fish meal (25.1%) and animal by-product mixture (16.38%) gave numerically the highest growth rate after 13 weeks of feeding, although growth reductions in fish fed diets exclusively with mehaden meal (77.6%) as protein or substituted with 50% animal by-product protein were not significant. Instantaneous mortality rates were the highest between weeks 2 and 4 of rearing and increased almost proportionally with the increased fish meal protein substitution. A diet based on menhaden fish meal had the highest concentration of phosphorus and several other essential minerals, but these were not reflected in the mineral composition of the fish body at the termination of feeding. Among activities of digestive enzymes, trypsin was depressed in fish offered diets with 75‐100% fish meal protein replacement. A diet superior in terms of fish performance was defined in the present study and it was concluded that the initial feeding can greatly affect physiological status of juvenile channel catfish.

The effects of aloe-supplemented feeds on nonspecific immune responses and disease resistance were determined in juvenile rockfish (Sebastes schlegeli). Experimental fish, which were naturally infected with Vibrio alginolyticus during acclimation period, were fed to satiation once daily in triplicate groups with a commercial diet supplemented with 1 or 5 g aloe/kg diet or without aloe for 6 weeks. Dietary aloe had no significant influence on the serum lysozyme activity. The chemiluminescent (CL) responses of head kidney leucocytes from fish given control and 1 g aloe/kg diet were significantly higher (p

This experiment was conducted to study the effects of different levels of dl -α-tocopheryl acetate on vitamin E status of juvenile Korean rockfish and estimate the dietary vitamin E requirement. After 6 weeks of conditioning with a basal diet, fish were divided into six groups and fed semipurified diets for 20 weeks. The experimental diets were supplemented with 0, 20, 40, 60, 120 or 500 mg dl -α-tocopheryl acetate/kg diet (E0, E20, E40, E60, E120 and E500). These diets contained approximately 16 mg of endogenous α-tocopherol/kg. Fish averaging 12.3 g were fed twice a day during the first 8 weeks, and then once a day during the second 16 weeks. Fish were fed to satiation throughout the experimental periods. Fish fed diet E0 began to show lower appetite and reduced growth rate after 16 weeks. Fish fed diet E0 had lower (P dl -α-tocopheryl acetate supplementation (diet E500) did not result in greater growth performance or liver α-tocopherol concentration than the other diets. Fatty acid composition of muscle and liver were only affected by the diet E0 (P

A 6-week feeding trial was conducted to determine the amount of dietary hemoglobin powder (HP; 92% crude protein, CP) that could be used to replace fish meal (FM, 68% CP) in the diet of juvenile Nile tilapia Oreochromis niloticus. Fish were fed eight isonitrogenous diets that contained FM, HP, or both as the dietary animal protein sources. Fish meal was used as the only source of animal protein (20%) in the control diet. Percent replacement of FM by HP on the basis of crude protein were as follows; 0% (control, diet 1), 12.5% (diet 2), 25% (diet 3), 50% (diet 4), 100% (diet 5), 25% + amino acids (AA) (diet 6), 50% + AA (diet 7), 100% + AA (diet 8). Weight gain (WG) and specific growth rate (SGR) of the fish fed experimental diets 2, 3, 4, 6, and 7 were not significantly different (P > 0.05) from those of fish fed the control diet. Feed conversion ratio (FCR), protein efficiency ratio (PER), and protein productive value (PPV) of fish fed diets 2, 3, 4, 5, 6, and 7 were not significantly different ...

Two consecutive 6-week feeding trials were conducted to determine the amount of haemoglobin powder (BM) that could replace fish meal (FM) in juvenile Japanese eel Anguilla japonica (Temminck et Schlegel) diets. Fish were fed 50% crude protein diets in which each of ten isonitrogenous diets was formulated to contain white fish meal and/or blood meal as the dietary protein source to replace FM by BM as follows: Diet 1 (control), 0% BM; diet 2,12.5% BM; diet 3,25% BM; diet 4, 50% BM; diet 5, 75% BM; diet6,100%BM;diet7,25%BM + 3 Essential Amino Acids (EAA); diet 8, 50% BM + 3 EAA; diet 9, 75% BM + 3 EAA; diet 10, 100 BM + 3 EAA. In the first 6-week period, the results were not consistent with the treatments, and poor adaptation of the fish to the experimental diets and conditions was observed. In the second 6-week period, weight gain, specific growth rate, protein efficiency ratio and protein productive value offish fed diets 2, 3, 4, 7, 8 and 9 were not significantly different from those of fish fed the control diet (P > 0.05). However, feed conversion ratios offish fed diets 6 and 10 were lower than that offish fed the control diet (P < 0.05). These results demonstrate that FM can be replaced by BM up to 50% without supplementation of three EAA, and up to 75% with three EAA supplementation in juvenile Japanese eel diets.

A 10-week feeding trial was carried out to evaluate the optimum dietary protein level for the maximum growth of juvenile beluga, Huso huso. Fish averaging 1.34 0.07 g (mean SD) was randomly distributed into 18 circular fibreglass tanks of 500 L capacity (20 fish per tank). Six iso-caloric diets were formulated to contain 30 (CP30), 35 (CP35), 40 (CP40), 45 (CP45), 50 (CP50) and 55% (CP55) crude protein (CP). Fish were fed each of the six experimental diets in triplicate groups. At the end of feeding trial, weight gain (WG) and specific growth rate (SGR) in fish fed CP40 and CP45 diets were significantly higher than those of fish fed CP30 ,C P35 ,C P50 and CP55 diets (P < 0.05). Lipid retention increased significantly from 24.7% to 31.6%, but protein retention decreased from 54.6% to 35.6% with increasing protein levels from 30% to 50%. Muscle total essential and non-essential amino acid (EAA & NEAA) concentrations increased with the dietary protein level up to CP45 diets. Muscle total EAA concentrations (%) of fish fed CP45 were significantly higher than those of fish fed CP30 ,C P 35 ,C P 50 and CP55, but there was no significantly different between those of fish fed CP40 and CP45. Muscle total NEAA concentration (%) of fish fed CP45 were significantly higher than those of fish fed CP30 and CP35 diets. Broken-line analysis of WG suggested that the optimum dietary protein level could be 38.9% for maximum growth performance in juvenile beluga (1.3–77 g).

A 10-week feeding trial was conducted to evaluate the tissue level synergistic effects of dietary vitamin C, E and selenomethionine (SeMet) on dietary methylmercury (MeHg) toxicity in juvenile olive flounder, Paralichthys olivaceus. Eight semi-purified diets were formulated to contain two different vitamin C levels as L-ascorbyl-2-monophosphate (400 and 800 mg AMP/kg diet), two vitamin E levels as DL-α-tocopheryl acetate (100 and 200 mg TA/kg diet) and two selenium (Se) levels as selenomethionine (2 and 4 mg SeMet/kgdiet) on the constant mercury (Hg) level (20 mg MeHg/kgdiet). Eight experimental diets, in a 2×2×2 factorial design (C400E100Se2, C400E100Se4, C400E200Se2, C400E200Se4, C800E100Se2, C800E100Se4, C800E200Se2 and C800E200Se4) were fed to triplicate group of fishes averaging 3.12±0.04g (mean±SD) in the semi-recirculation system. After 10 weeks of feeding trial, weight gain (WG) offish fed diets containing C400E200Se4, C800E100Se2 and C800E200Se2 were significantly higher than those of fish fed diets containing C400E100Se2 and C400E100Se4 (P

Semipurified diets containing either 25% or 30% crude protein (CP) from soy isolate (soy) or 30% CP from casein and gelatin (casein) were supplemented with either of two levels of L-lysine HCI (0 or 0·5% of diet) in a 3 × 2 factorial arrangement and fed to fingerling channel catfish, Ictalurus punctatus (Rafinesque), in aquaria for 8 weeks. Factorial analysis of variance indicated a significant (P < 0·001) positive effect of lysine on weight gain, protein conversion efficiency (PCE) and feed efficiency. Fish fed the soy diet containing 25% CP showed increased weight gain of 24% with lysine supplementation while fish fed soy and casein diets containing 30% CP showed increases of 11 % and 3%, respectively. However, supplementing the 25% CP soy diet with 0–5% L-lysine HCI did not enhance growth performance to the level offish fed the unsupplemented 30% CP soy diet. Significant effects of dietary protein levels and sources on weight gain, PCE, feed efficiency, haematocrit, hepatosomatic index (HSI; % liver weight), intraperitoneal fat (IPF) ratio, dry matter of fillet and whole-body, as well as lipid and protein content of whole-body tissue, were also observed. Fish fed the casein diet containing 30% CP had the greatest weight gain, PCE, feed efficiency, haematocrit and whole-body protein values and lowest IPF ratio and whole-body lipid values compared with those of fish fed the soy diets. Supplemental lysine did not affect body condition indices or proximate composition of whole-body and fillet tissues of fish fed the different protein sources. Therefore, based on this study, dietary protein levels and sources significantly influenced performance characteristics of channel catfish and supplemental lysine was most beneficial at a reduced CP level.

Resume Jaramillo Jr. F., S. C. Bai, B. R. Murphy, D. M. Gatlin III. Aquat. Living Resour., 1994, 7, 87-91. A non-destructive method for determining water, protein, lipid and ash content along with lean body mass (LBM; total body mass - total lipid mass) in live channel catfish was evaluated. This non-invasive technique involved placing the fish within a low-frequency electromagnetic field and measuring the total body electrical conductivity (TOBEC) based on the distinct electrical characteristics of body fat and fatfree tissues. The correlations between TOBEC and whole-body composition were examined using age-1' channel catfish ranging from 44 to 175 g. Significant linear relationships between TOBEC, body weight, and total length, or combinations of these parameters, and LBM, ash, lipid, protein, and water content were found; 3 values ranged from 0.863 to 0.998. Equations for predicting body composition from TOBEC and morphometric measurements were developed. Analysis of an independent group of fish demonstrated TOBEC equations to be reliable predictors of body composition. This technique should allow successive monitoring of body composition of individual fish at different times and provide additional insight into the body composition dynamics of channel catfish.

Fingerling channel catfish Ictalurus punctatus were fed purified diets either unsupplemented and deficient in both selenium and vitamin E, deficient in either selenium or vitamin E, adequate in both selenium (0.2 mg/kg) and vitamin E (60 mg/kg), or excessive in both nutrients (four times the recommended levels). After 115–120 d of feeding the experimental diets, the red blood cell membranes offish fed diets deficient in vitamin E were more susceptible to peroxidation than were those of fish fed diets that met or exceeded vitamin E recommendations. Hepatic, selenium-dependent glutathione peroxidase activity was suppressed in fish fed diets deficient in selenium when compared with this enzyme activity in fish fed diets containing recommended or higher levels of selenium. Intracellular superoxide anion production of macrophages was higher in fish fed the diet fortified with four times the recommended levels of both nutrients than in fish fed the other diets. None of the results indicated that seleni...

Semi-purified casein/gelatin diets containing two levels of lipid (5 or 10%) and three levels of reduced glutathione (0,0·1 or 1·0%) in a factorial arrangement were fed to fingerling channel catfish, Ictalurus punctatus (Rafinesque), in aquaria for 10 weeks. Factorial analysis of variance indicated that dietary lipid had significant (P < 0·05) effects on growth, feed efficiency and body composition of channel catfish. Diets containing 10% lipid generally produced higher weight gain and feed efficiency values as well as higher intraperitoneal fat. The higher level of dietary lipid also produced lower moisture and higher lipid (on a wet-weight basis) levels in whole-body and fillet tissues. Stability of fillet samples was estimated by 2-thiobarbituric acid (TBA) analysis which revealed that 10% dietary lipid significantly elevated fillet TBA values while glutathione did not have any effect. Therefore, dietary lipid level altered growth and body composition of channel catfish as well as oxidative stability of fillet samples while dietary glutathione was generally ineffective.

Semipurified diets containing 30% crude protein from casein and gelatin were supplemented with three concentrations of dl-α-tocopheryl acetate (0, 240 or 1000 mg/kg) and fed to channel catfish (initial average weight = 36.4 g) for 6 weeks. Factorial analysis of variance indicated a significant (P

For the 21st century, one of the most important challenges of the fisheries and aquaculture industries around the world is climate change and the shortage of high quality aquatic products. Experts ...

A study was conducted to determine the possible synergistic effects between dietary rutin (a bioflavonoid) and vitamin C, and to evaluate their antioxidant effects in fingerling channel catfish. Purified casein/gelatin diets containing two levels of rutin (0 and 1000 mg/kg diet) and three levels of L-ascorbic acid (0, 1500 and 3000 mg/kg diet) in a factorial arrangement were fed to fingerling channel catfish for 16 weeks. Fish fed the diets without supplemental vitamin C showed deformed spinal columns, external hemorrhages and fin erosion after 10 to 12 weeks. Also these fish had significantly (p < 0.05) depressed body weight gain, feed efficiency, hematocrit, hepatosomatic index (% liver weight), as well as reduced liver, fillet and plasma vitamin concentrations after 16 weeks. Liver, fillet and plasma vitamin C concentrations were correlated with dietary vitamin C levels. Forced oxidation of fillet samples significantly (p < 0.05) increased 2-thiobarbituric acid (TBA) values of fillets from fish fed diets without vitamin C and rutin. However, results from the present study indicated only limited synergistic effects of dietary rutin on vitamin C nutrition of channel catfish.

Two experiments were conducted to investigate the effects of natural and synthetic antioxidants in the diet on body composition and storage quality of channel catfish. An initial 12-week feeding trial in aquaria evaluated semipurified casein/gelatin diets containing two levels of vitamin E (60 or 240 mg dl-α-tocopheryl acetate/kg) with (1) no synthetic antioxidant, (2) ethoxyquin (150 mg/kg), or (3) butylated hydroxytoluene (10 mg/kg) in a factorial arrangement. In a separate 10-week feeding trial, similar diets containing vitamin E at two levels (60 or 240 mg dl-α-tocopheryl acetate/kg) with (1) no synthetic antioxidant, (2) butylated hydroxyanisole (10 mg/kg), or (3) Endox TM (125 mg/ kg) were evaluated. None of the antioxidants tested significantly altered growth, feed efficiency or proximate composition of whole-body and fillet tissues. Fish fed diets with 240 mg dl-α-tocopheryl acetate/kg had significantly higher levels of α-tocopherol in fillet samples than did those fed 60 mg dl-α-tocopheryl acetate/kg diet, but synthetic antioxidants in the diet did not affect tissue levels of α-tocopherol. Oxidation of lipids in frozen channel catfish fillets was determined by 2-thiobarbituric acid (TBA) analysis before and after 6 months at − 18 °C. Oxidative stability of fillets from catfish fed all dietary treatments was not significantly reduced during the 6-month storage period. When oxidation of the fillets was forced by flushing the samples with oxygen, TBA values were significantly reduced in samples from fish fed the higher level of vitamin E; whereas none of the synthetic antioxidants reduced oxidation. These data indicate that increasing supplemental vitamin E in the diet from 60 to 240 mg dl-α-tocopheryl acetate/kg provides additional protection against lipid oxidation in fillet tissue.

Summary The effects of dietary l-carnitine on growth performance, whole body composition and feed utilization were studied in beluga, Huso huso. Fish were randomly allocated in 15 tanks (30 fish per tank) and triplicate groups were fed to satiety during 84 days one of five isonitrogenous (41% CP) and isoenergetic (20 MJ kg−1) diets, each differing in l-carnitine content [0 (control), 300, 600, 900 and 1200 mg kg−1 diet]. At the end of the trial, fish grew from 19- to 23-fold in weight, from 8.4 g to a maximum of 191 g. Fish fed 300–600 mg l-carnitine had the highest specific growth rate (SGR, 3.69 and 3.72% day−1) and protein efficiency ratio (PER, 0.95 and 0.99), and the lowest feed conversion ratio (FCR, 1.4 and 1.3) than the other groups (P

Vibrio anguillarum is the causative agent of the fish disease vibriosis and is the most intensely studied species of Vibrio. In the present study, specific primers and a PCR assay were designed to detect V. anguillarum. The primers were designed to amplify a 429-bp internal region of the V. anguillarum amiB gene, which encodes the peptidoglycan hydrolase N-acetylmuramoyl-L-alanine amidase. PCR specificity was demonstrated by successful amplification of DNA from V. anguillarum and by the absence of a PCR product from 25 other Vibrio strains and various enteric bacteria. The PCR produced a 429-bp amplified fragment from as little as 1 pg of V. anguillarum DNA. The limit of detection for this PCR technique was c. 20 bacterial colonies in 25 mg of infected flounder tissue. These results suggest that this PCR system is a sensitive and species-specific detection method, and is possible to use as a diagnostic tool to detect V. anguillarum.

The present study examined the distribution of particle sizes in two experimental standardized lipid emulsions (distributed by ICES, International Council for the Exploration of the Sea) as a function of the preparation method (hand shaking or ultrasonic blending) and as a function of storage time. A 24-h enrichment trial compared the incorporated HUFA levels in the nauplii of Artemia franciscana. The emulsion droplets in the 50% HUFA emulsion (ICES 50, ethyl ester based) were much smaller than in the 30% HUFA emulsion (ICES 30, triacylglycerol-based) in which 90% of the droplets had a diameter below 12.3 μm as compared to 1.3 pn in ICES 50. The blending method highly affected particle sizes. High-shear blending instead of the classical hand shaking of the emulsion of both ICES 30 and 50 reduced the mean particle size from 5.06 to 1.07 μm and from 0.38 to 0.11 μm, respectively. The particle size distributions remained stable during the 1-wk storage, suggesting the absence of agglomeration or bacterial development. The fatty acid composition of 24-h enriched Artemia reflected differences in the HUFA profile of the emulsions, but was independent of observed differences in the size of the particles.

Diets incorporating three different sources of extracted cottonseed meal (CM), soybean meal and an animal protein mixture were evaluated for juvenile rainbow trout. Fish averaging 0.96 g were divided into groups of 30; 3 groups per treatment, and each group was fed one of four diets for a 16-week period. Fish meal (FM) was replaced on a 25% protein basis by each of three different sources of CM from California (CA), Tennessee (TN), and Arkansas (AR), U.S.A. In the three CM-containing diets another 25% soybean meal protein and 50% animal protein mixture were also incorporated to completely replace FM protein. The results of growth rate and feed utilization showed that FM could be entirely replaced by a mixture of plant proteins (CM and soybean meal) and animal by-product proteins. Hematocrit levels were significantly lower in the group fed CM-containing diets than in the control. The findings suggest that CM can be used as a good protein source by the incorporation of at least 15% in diets (25% of fish meal protein replacement), and that the nutritive values of CM in juvenile trout can be different due to their different origin. Significantly higher concentrations of total gossypol were found in faeces of CM-TN (5.8 +/- 0.4 micromol/g) and CM-AR (5.6 +/- 0.6) groups than in that of CM-CA (3.7 +/- 0.4) group. It was documented that gossypol enantiomers, present in an equal proportion in diets, selectively accumulated in liver and bile, whereas equal proportions of (+)- and (-)-enantiomers were found in whole-body and faeces. Depending on CM source, fish can absorb approximately 35-50% of dietary gossypol, and the majority of the absorbed gossypol seemed to be excreted.

Total activity [pyridoxal 5'-phosphate (PLP) added in the assay] of hepatic tyrosine aminotransferase (TAT) measured in cats at 0300, 0900, 1500 and 2100h was 10.3 +/-1.1, 14.0 +/- 0.7, 9.8 +/- 1.3 and 11.0 +/- 0.7 nkat/g liver, indicating little diurnal variation. Activity after 18 h of food deprivation was 10.0 +/- 0.3 nkat/g liver, also not different from cats that were eating ad libitum. These findings support the idea that cats have only limited changes in the activity of hepatic TAT compared with rats. Total TAT activity was measured in cats fed high protein (550 g/kg) and low protein (180 g/kg) diets for 4 wk. Cats fed a high protein diet had activities significantly higher (about twice) than cats fed the low protein diet. Hepatic TAT activity of vitamin B-6-deficient cats (diet without pyridoxine for 9 wk) was compared with cats given the same diet with 8 mg pyridoxine/kg. Total hepatic TAT activity in deficient cats was significantly (P < 0.05) lower per gram soluble or total protein (but not per gram liver) than control cats; holoenzyme activity and percentage of active enzyme in deficient cats were also significantly lower by 75 and 64%, respectively. The apparent Km of TAT from cats for tyrosine (2.1 mmol/L) was similar to that for rats (1.9 mmol/L), but higher for PLP in cats (0.16 micromol/L) than rats (0.034 micromol/L). Part of the reason for the higher plasma tyrosine in vitamin B-6-deficient cats than rats is the higher Km of TAT for PLP in cats than rats.

Vitamin B-6 deficiency has been reported to produce behavioral, neurophysiological and neuropathological abnormalities in a variety of species. In this investigation we used brainstem auditory evoked potentials (BAEP) to determine if vitamin B-6 deficiency in cats affected peripheral and brainstem auditory pathways. Brainstem auditory evoked potentials were recorded from growing cats as they developed vitamin B-6 deficiency, which was confirmed using clinical, hematological and urinary criteria. The BAEP interwave intervals measured from early (wave 1 or 1N) to late waves (5N) or from middle (wave 3) to late waves increased significantly, whereas interwave intervals from early to middle waves did not differ significantly. These results indicate that vitamin B-6 deficiency affects one or more structures of the brainstem that generate the later parts of the BAEP. The finding of prolonged interwave intervals in vitamin B-6-deficient animals is consistent with slowed axonal conduction velocity secondary to defective myelination. Recording BAEP provided a noninvasive means of detecting effects of vitamin B-6 deficiency on specific parts of the central nervous system.

A depletion-repletion model was used to study the effect of the level of dietary protein on the vitamin B-6 requirement of growing kittens. Twenty kittens were given a pyridoxine-free diet for 42 d to deplete vitamin B-6 reserves. They then were divided into four groups of five kittens each. Two groups were fed diets containing 30% casein with either 1.0 (Group 30-1) or 2.0 (Group 30-2) mg pyridoxine/kg diet and two groups were fed 60% casein diets with either 1.0 (Group 60-1) or 2.0 (Group 60-2) mg pyridoxine/kg diet for 44 d. During repletion, body weight gain of kittens from Group 30-2 was higher than that of kittens from the other groups. Body weight gains of kittens from Groups 30-1 and 60-2 were higher than that of kittens from Group 60-1, but there was no difference in body weight gain between Groups 30-1 and 60-2. At 44 d of repletion, kittens from Group 60-1 generally had higher plasma concentrations of free tyrosine and cystathionine, lower plasma B-6 vitamin concentrations and a higher urinary oxalate excretion than did kittens from the other groups. These findings indicate that the vitamin B-6 requirement of growing kittens--as is true of humans, chickens and mice--is positively related to the level of protein in the diet. For a 30% casein diet, the vitamin B-6 requirement was greater than or equal to 1.0 but less than 2.0 mg pyridoxine/kg diet; for a 60% casein diet, the requirement was greater than or equal to 2.0 mg pyridoxine/kg diet.

Activity of lipases in adipose tissue during pregnancy and lactation was investigated in Holstein cows producing 5950 to 10,000 kg milk per 305 d. Activity of cytoplasmic lipoprotein lipase per gram of tissue was 97, 78, 140, 162, 179, and 235% of 30 d prepartum at -15, 15, 30, 60, 180, and 349 d about calving in yr 1. In yr 2, lipoprotein lipase per gram was 100, 259, 838, 791, and 430% of -30 d at -15, 30, 60, 120, and 180 d. Adaptations in activity per milligram cytoplasm protein were similar to those per gram tissue. Hormone-sensitive lipase per milligram protein was 161, 251, 114, 126, and 252% of -30 d when measured at 30, 60, 120, 180, and 240 d postpartum. Activity per gram of tissue responded similarly to the lactation state. Lipoprotein lipase is thus not a large contributor to the peripartum bovine adipose adaptation but is important in reattainment of body composition in mid and late lactation. Hormone-sensitive lipase is also increased during peak and midlactation. The pattern of elevated activity of these oppositely directed lipases reflects the dichotomous forces of milk fat production and body fat recovery acting on adipose tissue of lactating heifers.

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.

Two experiments were conducted to determine the vitamin B-6 requirement for growing kittens. Ten kittens were divided into two groups and given a purified diet containing 8.0 mg pyridoxine (PN)/kg diet (+PN) or a PN-free diet (-PN) for 11 wk. Daily body weight gain, food intake, weekly plasma free amino acids, plasma B-6 vitamers, urinary oxalate excretion, hemoglobin (Hb) and hematocrit were measured. Kittens fed a -PN diet had depressed body weight gain, food intake, plasma pyridoxal phosphate (PLP) and pyridoxal (PL), Hb and hematocrit, and had elevated urinary oxalate, plasma tyrosine and plasma cystathionine. In a second experiment, 24 kittens were given a -PN diet for 45 d to deplete their body reserves. The kittens were then divided into six groups of four kittens each and given a purified diet containing either 0.5, 1.0, 2.0, 3.0, 4.0 or 8.0 mg PN/kg diet for 46 d. Following supplementation, positive responses in body weight gain, PLP, Hb and hematocrit, and decreased urinary oxalate excretion, plasma tyrosine and plasma cystathionine occurred in all groups except those fed 0.5 mg PN/kg diet. At the end of the repletion period, kittens fed 1.0 mg PN/kg diet had lower body weight gain, higher plasma tyrosine and cystathionine, slower rate of decrease in urinary oxalate, and lower values for Hb, hematocrit and PLP than did the kittens from groups fed 2.0-8.0 mg PN/kg diet. These findings indicate that the dietary requirement for PN is greater than 1.0 mg/kg diet, but 2.0 mg PN/kg diet is adequate for growing kittens given a 35% casein diet.

The effects of Ohio State University (OSU) meal (a mixture of blood meal, meat and bone meal, poultry by-products and feather meal), as partial or total replacement of fish meal was investi- gated. Thirty-two fish tanks, each containing 30 rainbow trout (initial mean weight 1.93 g), were fed one of 10 diets (the control had only two replicates) containing a different quantity of OSU meal for 14 weeks. The trout fed the diets containing 20% or 40% OSU meal grew similarly to the trout fed the fish meal based diet. Total replacement of the fish meal caused a significant reduction in growth (p

A feeding trial was conducted to evaluate the effects of two different sizes of extruded pellets (EP) (EP1 - 3 mm or EP2 - 5 mm) and a moist pellet (MP) in olive flounder, Paralichthys olivaceus, reared in semi-recirculation system. A total of 450 fish with an average initial weight of 5.0 ± 0.2 g (mean ± SD) were fed one of the three experimental diets in triplicate groups. At the end of a 6-week feeding trial, weight gain, specific growth rate, and feed efficiency of fish fed EP diets were significantly higher than those of fish fed MP (P