bluuebunny/crossref_metadata_2025 huggingface dataset:
Ingestion, Absorption, and Gonad Production of Adult Strongylocentrotus franciscanus Fed Different Rations of a Prepared Diet
Authors: McBride Susan C. , Lawrence John M. , Lawrence Addison L. , Mulligan Timothy J.
Published: April 2007

Abstract.— Feed costs are a major portion of aqua‐culture operations. Accurate estimates of daily ration are vital to prevent overfeeding which results in wasted feed. poor water quality, underfeeding, and reduced growth. Understanding the relationship of ingestion rate and absorption efficiency of Strongylocentrotus franciscanus should improve the cost effectiveness of aquaculture of this candidate species. Adult S. franciscanus were collected from a subtidal area devoid of algae and fed two rations of an extruded diet for 62 d. Mean test diameter and whole weight of an initial sample were 91 ± 2 mm and 295 ± 18.4 g (mean ± SEM; N = 16). The two rations used were l‐g dry feed/d or 3 g/d. An unfed control group was also maintained. Eight urchins per treatment showed significant differences in food ingestion rate, total organic absorption, gonad index, gut index, and moisture content of the gonad (P < 0.001). Food intake was greatest in the high ration treatment, while total organic absorption was greatest in the low ration treatment. The gonad index of S. franciscanus in the high food ration was significantly greater than the initial gonad index and was also greater than the index of animals in the low ration and unfed treatments. The gonad index of animals in the low food ration treatment was significantly greater than the index of the initial sample and the index of animals in the unfed treatment. The gut index of urchins in the high food ration treatment was significantly greater than initially and was also greater than the gut index for animals in the low ration and unfed treatments. The gut index for urchins in the unfed treatment was significantly less than the initial index. The moisture content of the gonad of urchins fed the prepared diet was significantly greater than the gonad moisture content of the initial sample or unfed group. Test diameter. whole animal weight, and gonad production efficiency (increase in g dry gonad weight/g dry feed intake) were not significantly different (P > 0.200). Histological examination of the gonads showed S. franciscanus in the two ration treatments developed from the spent to the growing or premature stage while the unfed controls lost nutritive tissue and contained only relict gametes or remained in the spent condition. The results suggest S. franciscanus from food‐limited environments can be fed appropriate rations to control gonad production.
Growth, Yield, Dressout, and Net Returns of Bighead Carp Hypophthalmichthys nobilis Stocked at Three Densities in Fertilized Earthen Ponds
Authors: Engle Carole R. , Brown David
Published: April 2007

Abstract.— Bighead carp Hypophthalmichthys nobilis have been raised in the United States for two decades and sold through the livehaul market, but their profitability in monoculture has not been evaluated. Three studies were conducted in 0.10‐ha earthen ponds to evaluate the effect of bighead carp stocking density on growth, yield, dressout yield. and net returns. Initially, bighead carp (average weight of 0.36 kg) were stocked at rates of 500, 320, or 130 fish/ha with three replicates of each treatment. Stocking rates for 2‐yr‐old fish (average weight of 2.45 kg) were reduced to 320, 220, or 130 fish/ha in the second year. Net yields of bighead carp stocked at 500 fish/ha (963 kg/ha) were significantly higher (P < 0.05) than net yields at the 320 fishha density (771 kg/ha), and these were significantly greater (P < 0.05) than net yields at 130 fish/ha (369 kg/ha) in the first growing season. Net yields in the second growing season were not significantly different (P > 0.05) among densities. There were no significant differences (P > 0.05) among treatments in yearly growth which ranged from 11–17 g/d in the first and from 6–13 g/d in the second growing season. Dressout percentages for whole‐dressed, steak, shank fillet, and shank fillets with white meat only did not differ with stocking density (P > 0.05). Enterprise and partial budget analysis indicated that monoculture of bighead carp in fertilized ponds is profitable only in the short run at average livehaul market prices, because revenues exceeded variable but not fixed costs. The negative net returns, when all costs were accounted for, indicated that it is not profitable to construct ponds solely for monoculture of bighead carp.
Evaluation of Practical Diets with Various Levels of Dietary Protein and Animal Protein for Pond‐Raised Channel Catfish Ictalurus punctatus1
Authors: Robinson Edwin H. , Li Meng H.
Published: April 2007

Three levels of dietary protein (26, 28, or 32%) and four levels of animal protein (0, 2, 4, or 6%) were evaluated in a factorial experiment for pond‐raised channel caffish using practical‐type extruded feeds. Meat, bone, and blood meal (65% protein) was used as the animal protein source. Channel catfish fingerlings (average weight: 69 glfish) were stocked into 48 0.04‐ha ponds at a rate of 24,700 fishha. Four ponds were used for each dietary treatment. Fish were fed once daily to apparent satiation for 158 d. No differences were observed in weight gain, feed consumption, feed conversion ratio, survival, and hematocrits of channel catfish fed diets containing various levels of dietary protein and animal protein. Inclusion of animal protein in the diet did not affect fish dressout, percentage visceral fat, or fillet composition. Comparison of means pooled by dietary protein without regard to animal protein showed that fish fed diets containing 26% protein had a lower percentage dressout than fish fed higher protein diets (55.4% vs. 56.3%). Fish fed the 32% protein diet had lower visceral fat than those fed the 26% or 28% protein diet (2.9% vs. 3.6% or 3.4%). Fillet fat was lower for fish fed the 32% protein diet than for fish fed the 26% protein diet (5.8% vs. 7.1%). Fillet fat in fish fed the 28% protein diet (6.5%) was not different from fish fed either 26% or 32% dietary protein. No differences were detected in fillet protein, moisture, and ash concentrations among fish fed diets containing various concentrations of protein. There were no interactions between dietary protein and animal protein for any variables. Results from the present study indicate that animal protein can be eliminated from diets for grow out of channel catfish fed to apparent satiation using diets containing 26% to 32% crude protein.
Evaluation of Direct and Indirect Techniques for Measuring Absorption Efficiencies of Sea Urchins (Echinodermata: Echinoidea) Using Prepared Feeds
Authors: Lares M. T.
Published: April 2007

Measurement of absorption efficiencies is essential for evaluating feeds for the culture of marine invertebrates. There are currently several direct and indirect techuiques that may be used for measuring absorption efficiencies in sea urchins. Three of these methods were evaluated and compared. Based on this evaluation, the conditions under which each technique should be used are reviewed. Direct measures require complete fecal collection and should not be used for estimating absorption efficiency. Ash can be used as a marker to estimate absorption efficiencies under most circumstances, but absorption efficiencies tend to be overestimated as the inorganic fraction decreases slightly with passage through the gut. Chromic oxide can only be used as a marker for estimating absorption efficiencies when complete fecal collection is made, as it may pass through the gut at a different rate than the rest of the egesta.
Larval Rearing of Common Carp Cyprinus carpio: A Comparision Between Natural and Artificial Diets Under Three Stocking Densities
Authors: Sharma J. G. , Chakrabarti Rina
Published: April 2007

Common carp Cyprinus carpio larvae were cultured under two feeding conditions: live food or an artificial diet for 40 d in recirculating systems. Three stocking densities of 25 (low), 50 (medium), and 100 (high) larvae/15‐L aquarium were maintained for each feeding treatment. Significantly higher survival (91%) and growth (401.08 ± 2.61 mg) were observed in the low density, live food system. Average weight of larvae in the live food system was 3‐ to 5‐fold higher than larvae at the same stocking density for the artificial diet. Proteolytic activity showed a direct relationship with the length of the digestive tract (r = 0.95). The highest enzyme activity was observed in the low density, live food system. Survival and growth of common carp larvae are influenced by both the stocking density and the type of food.
Remediation of Cayuga Syndrome in Landlocked Atlantic Salmon Salmo salar Using Egg and Sac‐Fry Bath Treatments of Thiamine‐Hydrochloride
Authors: Wooster Gregory A. , Bowser Paul R. , Brown Scott B. , Fisher Jeffrey P.
Published: April 2007

A lethal thiamine deficiency, termed Cayuga Syndrome (CS), affects larval landlocked Atlantic salmon Salmo salar in several of New York's Finger Lakes. This syndrome has been linked to a maternal diet of alewife Alosa pseudoharengus that have high thiaminase concentrations within them and were not endemic to the Finger Lakes. We evaluated thiamine bath treatments at a range of concentrations for remediation of the syndrome (CS) by treating eggs during water‐hardening or sac‐fry at the onset of CS when clinical signs such as yolk sac and cerebral edema, vascular and mandibular abnormalities, and in particular when abnormal swimming, lethargy and yolk sac oppacities, first became evident. Concentrations of thiamine in sac‐fry from both treatments were elevated by a single 1‐h exposure of eggs or sac‐fry in a thaimine bath. Thiamine concentrations of at least 1,000 mg/L. during water hardening, or 10,000 mg/L if treated as moribund sac‐ky, were necessary to almost eliminate syndrome‐related mortality. When post‐treatment total thiamine tissue concentrations (i.e., the sum of thiamine pyrophosphate, thiamine mono‐phosphate and free thiamine) approached or exceeded a threshold of 0.8 nmol/g sac‐fry in the sac‐fry, mortality due to CS was significantly reduced. Earlier treatment at the egg hardening stage may provide a greater likelihood of avoiding long term effects of the deficiency.
Use of Krill Hydrolysate as a Feed Attractant for Fish Larvae and Juveniles
Authors: Kolkovski Sagiv , Czesny Sergiusz , Dabrowski Konrad
Published: April 2007

Abstract.— We determined the effect of krill hydrolysate as a feed attractant in three freshwater fish species: yellow perch Perca flavescens. walleye Stizostedion vitreium. and lake whitefish Coregonus clupeaformis. Growth trials were conducted using a commercial trout starter diet (control) and the diet that was coated with liquid krill hydrolysate. The krill hydrolysate coated diet increased growth of yellow perch juveniles by 31% compared to control diet (average final wet weight, 734 ± 33 mg and 559 ± 82 mg, respectively). Moreover. weight gains were not significantly different than for tish Id exclusively live Artemiu nauplii. Similar results were obtained with walleye juveniles fed either a trout starter diet or 5% krill hydrolysate coated diet (8.9 ± 0.25 g and 11.6 ± 5.1 g wet weight, respectively). The food conversion ratio (FCR) was lower in fish fed the control diet, although not significantly different (2.95 ± 0.18 and 3.69 ± 0.39. for control and coated diet. respectively). The effect of krill hydrolysate on dry diet ingestion rates of lake whitefish and yellow perch larvae was also determined using radioactive (14C) labelling. A commercial starter diet was coated with krill hydrolysate or the soluble fraction of krill hydrolysate was added to the experimental tank water. In both species. coating the diet with 5% krill hydrolysate resulted in significantly higher ingestion rates. Supplementation of krill hydrolysate soluble fraction to the tank water resulted in 200% increase in ingestion rate in comparison to control (uncoated starter diet), although it was not significantly different from krill coated diet and live Artemia nauplii ingestion rates.
Spray‐Dried Blood Cells as a Partial Replacement for Fishmeal in Diets for Rainbow Trout Oncorhynchus mykiss
Authors: Johnson J. Alan , Summerfelt Robert C.
Published: April 2007

Abstract.— The objective of this study was to evaluate growth of juvenile rainbow trout Oncorhynchus mykiss (81.4 mm initial length and 6.4 g initial weight) fed a diet containing 47.5% herring meal (FM diet) and a test diet containing 34.5% herring meal and 8.75% spray‐dried animal blood cells (SBC diet). Both diets were formulated to be isonitrogenous (48.5 and 48.0% protein) and isocaloric (3,977 and 3,927 kcal DElkg). At the end of the 12‐wk feeding trial, differences in growth rate and feed conversion ratios were not statistically significant between the two dietary treatments. Apparent crude protein digestibility was 89.7% for the SBC diet and 88.1% for the FM diet. Apparent net protein utilization and iron retention values were not different, but phosphorus retention was higher for fish fed the SBC diet. Whole body iron content of the fish decreased in both groups from 23.3 mg/ kg in an initial sample to 16.5 mg/kg in fish fed the FM diet and 18.4 mg/kg in fish fed the SBC diet at the end of 12 wk. The diet containing 8.75% SBC replaced 27.4% of the crude protein supplied by herring meal, and it had 22.7% less total phosphorus (P) than the fishmeal diet. The cost of gain for the FM diet was $0.508/kg gain compared to $0.512/kg gain for the SBC diet.
Patchiness Formation and Development of Schooling Behavior in Pacific Threadfin Polydactylus sexfilis Reared with Different Dietary Highly Unsaturated Fatty Acid Contents
Authors: Masuda Reiji , Ziemann David A. , Ostrowski Anthony C.
Published: April 2007

Abstract.— Nutritional condition in larval fish culture has generally been evaluated based on growth and survival, and stress tolerance by air exposure. Here we made direct observations of fish in rearing tanks to estimate the quality of the fish. Pacific threadfin Polydactylu.s sexfilis larvae were reared with rotifers and Artemia nauplii enriched with three levels of highly unsaturated fatty acids (HUFA). The three levels were defined as no‐, medium‐, or high‐HUFA groups, in which the fatty acids emulsions contained 0, 30, or 50%. respectively. of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The formation of patchiness (dense aggregations of fish on the surface) and development of schooling behavior were observed in four replicate rearing tanks for each feed treatment. Patchiness was formed in every tank with the highest densities of 60–250 fish/L on day 7–8 posthatch. Both medium‐HUFA and high‐HUFA groups showed schooling behavior at 19 d after hatching, whereas fish in the no‐HUFA group did not form schools even at day 25. The body lengths of fish from each group were not significantly different, although the no‐HUFA group suffered high mortality after day 20. Our results suggest that HUFA deficiency has a serious negative impact on P. sexfilis during metamorphosis rather than during the early larval stage. We also consider that direct observation rather than stress tests by air exposure may be an effective tool to measure the quality of juvenile fish.
A Profound Effect of Hyperthermia on Survival of Litopenaeus vannamei Juveniles Infected with White Spot Syndrome Virus
Authors: Vidal Oscar M. , Granja Clarlssa B. , Aranguren Fernando , Brock James A. , Salazar Marcela
Published: April 2007

This study was conducted to examine the effect of increasing seawater temperature on White Spot Syndrome Virus (WSSV) infection in juvenile Pacific White shrimp (Litopenaeus vannamei). Infection by WSSV was achieved using two methods, intramuscular injection and per os (oral) administration. Forty injected and 20 per os infected animals were kept in heated tanks at 32.3 ± 0.8 C, and the same number of WSSV infected animals were maintained in tanks at ambient temperature (25.8 ± 0.7 C). Despite the route of exposure, there were no survivors among the animals kept at ambient temperature; whereas, in heated tanks the survival of the WSSV infected juvenile shrimp was always above 80%, suggesting the existence of a beneficial effect from hyperthermia that mitigated the progression of WSSV disease. Moreover, this beneficial effect was not attributable to viral inactivation. Infected animals kept at 32 C had histologically detectable lymphoid organ spheroids suggestive of a chronic viral infection but were PCR negative (hemolymph) for WSSV. These findings might be related to low viral replication in WSSV‐infected shrimp held at the higher environmental temperature. When the WSSV‐infected shrimp were transferred from 32 C to ambient temperature, the mortality from WSSV ensued and was always 100%. Although the mechanism related to the beneficial effect of heating was not determined, our results indicate that increasing the water temperature modifies dramatically the natural history of the WSSV disease and the survival curves of WSSV‐infected juvenile Pacific White shrimp.
An Economic Analysis of the Performance of Three Sizes of Catfish Ictalurus punctatus Fingerlings Understocked in Multiple‐Batch Production
Authors: Engle Carole R. , Valderrama Diego
Published: April 2007

Abstract.— Different sizes of catfish fingerlings understocked in multiple‐batch production may result in different survival, yield, cost, and economic risk. A pond production study was conducted to compare net yield, growth, survival, costs, and economic risk of understocking 7.6‐cm, 12.7‐cm. or 17.8‐cm channel catfish Ictalurus punctatus fingerlings in growout ponds. Fingerlings were understocked at 15,000/ha with 1,369 kg/ha carryover fish averaging 0.58 kg. Mean growth rate increased significantly with size of fingerling understocked (1.4 ± 0.2 g/d, 1.8 ± 0.07 g/ d, and 2.2 ± 0.06 g/d for 7.6‐cm, 12.7‐cm, and 17.8‐cm understocked fingerlings, respectively). Mean individual weights at harvest also increased significantly with size at stocking but none of the understocked fingerlings reached minimum market size (0.57 kg) over the 201‐d study period. Survival of the smallest (7.6‐cm) understocked fingerlings was significantly lower, but there was no difference in survival between the two other treatments. Net yields were highest for the two treatments understocked with 12.7‐ and 17.8‐cm catfish and significantly lower for the treatment understocked with 7.6‐cm fish. Growth of large carryover fish was significantly less in the treatment understocked with 17.8‐cm fingerlings. Breakeven production costs were highest for the treatment understocked with 7.6‐cm fish and lower for the other two treatments. The risk analysis showed that it was very likely that the 12.7‐ and 17.8‐cm understocked fish could be grown profitably (very little risk of costs exceeding $ 1.32/kg—$1.65/kg). However, the risk of growing out 7.6‐cm understocked fish at costs above market prices increased sharply. This static analysis indicated that the preferred size to understock in growout ponds would be 12.7 cm; however, additional work is needed in a dynamic framework to quantify the benefit of 17.8‐cm fingerlings reaching market size earlier in the second year.
Filtration of Green Algae and Cyanobacteria by Freshwater Mussels in the Partitioned Aquaculture System
Authors: Stuart Kevin R. , Eversole Arnold G. , Brune David E.
Published: April 2007

Abstract.— The freshwater mussel Elliptio complanata was provided water containing green algae and cyanobacteria delivered from the Partitioned Aquaculture System (PAS) at eight flow rates to determine algal filtration rates as mg of particulate organic carbon (POC)/kg wet tissue weight per h. The dominant taxon in cyanobacterial waters was Microcystis while the dominant taxa in green algal waters were Scenedesmus and Ankistrodesmus. The cell counts of Scenedesmus and Ankistrodesmus were the only algal taxa that were significantly different between the incoming water and water filtered by mussels. Filtration rates of POC obtained from green algal water were significantly greater than from cyanobacteria‐dominated waters at all flow rates. A significant increase in mean filtration rate was observed as flow rates increased. The filtration rate of green algae increased as POC concentration increased, peaking at 28 mg C/L. A maximum filtration rate was not observed with cyanobacterial waters.
Effects of Dietary Chlorella ellipsoidea Supplementation on Growth, Blood Characteristics, and Whole‐Body Composition in Juvenile Japanese Flounder Paralichthys olivaceus
Authors: Kim Kang‐Woong , Bai Sungchul C. , Koo Ja‐Wan , Wang Xiaojie , Kim Se‐Kwon
Published: April 2007

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.
Apparent Digestibility Coefficients of Nutrients and Nutritional Value of Poultry By‐product Meals for Rainbow Trout Oncorhynchus mykiss Measured in vivo Using Settlement
Authors: Cheng Zongjia J. , Hardy Ronald W.
Published: April 2007

Fish meal production is not growing worldwide, therefore, it is important to search for alternative protein sources. Three types of poultry by‐product meals (feed grade, prime, and refined) and two fish meals (herring and menhaden) were mixed into a casein‐gelatin purified reference diet at 30% to measure apparent digestibility coefficients (ADCs) for rainbow trout Oncorhynchus mykiss. A total of 90 fish (initial mean body weight 294.6 ± 10.7 g) were stocked into six 140‐L fiberglass digestibility tanks at 15 fish per tank. Individual tanks were assigned randomly to each of the five experimental diets and the reference diet. Fecal collection by settlement lasted for 2 wk. Feces collected in each week represented a replicate, and they were analyzed separately. The ADCs of nutrients for herring meal, menhaden meal, feed grade poultry by‐product meal, prime poultry by‐product meal, and refined poultry by‐product meal were: dry matter, 81.3, 70.9, 70.9, 71.5, and 74.5%, respectively (P= 0.0168); crude protein, 89.8, 85.8, 83.1, 84.8, and 87.1%, respectively (P= 0.0032); crude fat, 91.5, 90.7, 79.7, 82.7, and 79.9%, respectively (P= 0.0004); ash, 76.6, 66.2, 74.1, 77.4, and 79.6%, respectively (P = 0.2880); phosphorus, 58.2, 46.9, 49.4, 45.8, and 56.0%, respectively (P = 0.0143); gross energy, 88.2, 84.0, 81.9, 83.4, and 79.8%, respectively (P= 0.2466). Significant differences in ADCs of essential amino acid existed only for arginine, leucine, and tryptophan when comparing refined poultry by‐product meal with herring meal. Results showed that refined poultry by‐product meal had similar ADC values to herring meal, thus, it has a similar nutritional value and can replace portions of herring meal in rainbow trout feeds. Furthermore, differences exist in ADC values among grades of poultry by‐product meals that should dictate appropriate use levels in rainbow trout feeds.
The Effect of Exogenous Hormone Treatment on Spermiation in Rhynchocypris oxycephalus (Sauvage and Dabry)
Authors: Park I.‐S. , Choi G. C. , Kim D. S. , Nam Y. K.
Published: April 2007

For the evaluation of hormonal control of spermiation in fish, a method to quanify the spermiation response of mature Rhynchocypris oxycephalus (Sauvage and Dabry) to hormonal therapy is described. Spermatocrit was determined after 7 min centrifugation at 18,000 ±g and sperm density was estimated by a standard hemocytomer method. Sperm density can be predicted from spermatocrit since their relationship is linear as described by the regression equation, Y = 3.68X ‐ 27.18 (R2= 0.82, N= 50). where Y is spermatocrit and × is sperm density. Milt production by mature R. oxycephalus was highest at 24 h after injection of 1,000 IU human chorionic gonadotropin (HCG) and 50 μg luteinizing hormone‐releasing hormone analogue (LHRHa) per kg body weight. Increased milt production coincided with low spermatocrit and sperm density levels. These results demonstrate that spermiation in mature R. oxycephalus can be reliably evaluated by a spermatocrit method and that HCG and LHRHa are effective in stimulating of spermiation in this species.
Diel Variation in RNA/DNA Ratios of Japanese Flounder Paralichthys olivaceus
Authors: Gwak Woo‐Seok
Published: April 2007

Laboratory‐reared Japanese flounder Paralichthys olivaceus larvae (11.2 ± 0.2 mm total length; age 26 d) were sampled over a 48‐h period to determine any diel patterns in RNA/DNA ratios. RNA/DNA ratios were highest during daytime periods (0800, 1100, 1400, 1700, 2000 h) and significantly reduced at night (2300, 0200, 0500 h). Findings from this study indicate a diel variation in biochemical condition and suggest that special care should be taken in sampling design and data analysis to account for this source of variability.
Mass Production of Juveniles of the Fat Snook Centropomus parallelus in Brazil
Authors: Alvarez‐Lajonchegre Luis , Cerqueira Vinicius R. , Silva Israel D. , Araujo Jaqueline , Reis Marcosdos
Published: April 2007

A pilot‐scale trial to rear fat snook Centropomus parallelus through larval, weaning and nursery phases was conducted in Florianópolis, Brazil. Eggs (96% fertilization) from captive broodstock, induced to spawn using 50 μg/kg LHRHa were stocked in two 4,000‐L cylindrical fiberglass tanks at a mean density of 19.2 eggs/L. Nannochloropsis oculata was stocked with the eggs and maintained at a mean density of 0.5–1.0 ± 106 cells/mL up to 31 dph (31 dph). Hatching averaged 90%. Larvae were fed rotifers Brachionus rotundiformis enriched with an oil emulsion from 3 dph to 36 dph (30–40 rotifers/mL) and Artermia meta‐nauplii enriched with Selco from 22 dph to 60 dph (mean 2.9 meta‐nauplii/mL). Weaning began at 45 dph with an artificial dry diet NRG (50% protein), supplied together with concentrated and enriched Artemia meta‐nauplii. No critical period of mortality was observed during larval rearing. During the 43 days of weaning and nursery, less than 1% mortality was recorded. Food conversion rate during nursery was 1.17, with a change in the coefficient of variation of mean total length of 1.3%. Specific total growth rate in weight was 13.0 %/d and mean growth in total length and total weight were 0.65 mm/d and 24.0 mg/d over the whole rearing trial respectively. Mean total length and total weight of juveniles were 57.6 ± 0.1 mm and 2.11 ± 0.12 g, respectively, and the length‐weight relationship was W = 8.29931 ± 10–5 TL3.049607 (r= 0.9986). on 88 dph when the trial was terminated. The condition factor on 88 dph was 1.104. On 88 dph a total of 35,000 juveniles were harvested, overall survival was 25.5% with mean final density of 4.4 fishn and biomass of 6.9 kg/m3. The present trial demonstrated the feasibility of mass production of fat snook. Possible improvements necessary for commercial cultivation of fat snook C. parallelus are discussed.
Effects of Dietary Energy Level and Number of Meals on Growth and Body Composition of Nile Tilapia Oreochromis niloticus (L.) During Summer and Winter Seasons
Authors: Cho Sung Hwoan , Jo Jae‐Yoon
Published: April 2007

Two feeding trials (experiments 1 and 2) were conducted to determine the combined effect of dietary energy levels (low energy, LE and high energy, HE) and number of daily meals (one meal with the entire daily amount, two meals with half of the daily amount, and three meals with one‐third of the daily amount) on the growth and body composition of Nile tilapia Oreochromis niloticus in a recirculating system at different water temperatures, representing winter and summer seasons. In experiment 1 (winter), weight gain and specific growth rate (SGR) were significantly (P < 0.05) affected by dietary energy levels, but not by number of meals. Weight gain and SGR for fish fed the LE diet one daily meal were significantly (P < 0.05) higher than for fish fed the HE diet in one daily meal. Feed efficiency ratio (FER) and energy efficiency ratio (EER) were significantly (P < 0.05) affected by dietary energy levels, but not by number of meals. Protein efficiency ratio (PER) was not significantly (P > 0.05) affected by either dietary energy levels or number of meals. However, protein retention was significantly (P < 0.05) affected by both dietary energy levels and number of meals. The chemical composition (moisture, protein, lipid, and ash) of fish muscle was not significantly (P > 0.05) affected by either dietary energy levels or number of meals. However, visceral fat content was significantly (P < 0.05) affected by dietary energy levels, but not by number of meals. In experiment 2 (summer), weight gain and SGR were significantly (P < 0.05) affected by number of meals, but not by dietary energy levels. Weight gain and SGR for fish fed the LE and HE diets in two daily meals were significantly (P < 0.05) higher than those fed one daily meal. FER and PER were significantly (P < 0.05) affected by number of meals, but not by dietary energy levels. The highest FER and PER were observed in fish fed two daily meals. EER was significantly (P < 0.05) affected by both dietary energy levels and number of meals. Moisture and protein content of the whole fish were not significantly (P > 0.05) affected by either dietary energy levels or number of meals. Lipid content was significantly (P < 0.05) affected by dietary energy levels, but not by number of meals. Based on the results of these experiments, Nile tilapia should not be fed high‐energy diets to improve fish performance even under a limited feed allowance during winter or summer. Fish grew rapidly when fed two daily meals during summer, but number of meals had no effect on fish performance during winter.
Acid and Fermented Silage Characterization and Determination of Apparent Digestibility Coefficient of Crude Protein for Pacu Piaractus mesopotamicus
Authors: Vidoiti Rose Meire , Carneiro Dalton Jose , Viegas Elisabete Maria Macedo
Published: April 2007

Three types of raw materials including commercial waste from saltwater (SW), freshwater fish (FW) and tilapia fillet residue (FR) were used to produce fish silage by either acid digestion (2% formic acid and 2% sulfuric acid) or anaerobic fermentation (5% of Lactobacillus plantarum and 15% sugar cane molasses). Six test diets were used in digestibility trials prepared with 70% reference diet and 30% of each experimental silage. These diets were fed to juvenile pacu Piaractus mesopotamicus (146 g average weight) in triplicate. Fish were kept in 500‐L tanks and feces collected by manual extrusion. It was observed for both processes that SW waste always had the highest moisture content and lowest fat and ash. Highest crude protein levels were found in silages from commercial fish waste (SW and FW) made from whole fish unfit for human consumption. However, apparent digestibility coefficients did not vary among diets (P > 0.05). Although values did not differ statistically, fermented silage consistently displayed higher digestibility coefficients compared to acid silage. The silages exhibited relatively high protein digestibility (72.5–80.0%), thus suggesting the feasibility of using fish industry by‐products in aquaculture feeds.
Growth and Feed Utilization of Captive Wild Subadult Black Sea Bass Centropristis striata Fed Practical Diets in a Recirculating System
Authors: Copeland Kimberly A. , Watanabe Wade O. , Carroll Patrick M.
Published: April 2007

The effects of four practical diets on growth, feed utilization, and body composition of wild‐caught juvenile and subadult black sea bass Centropristis striata (316 ± 113 g =±± SD) were compared for 221 d in a recirculating tank system consisting of 12 2,660‐L tanks. Salinity averaged 33.5 ppt and temperature averaged 20.9 C but vaned from 12 to 27.1 C. Diets differed in crude protein (CP) and crude lipid (CL) as follows: 1) low CP (44.0%), low CL (11.4%) trout diet; 2) low CP (44.8%), high CL (15.0%) trout diet; 3) midlevel CP (47.9%), midlevel CL (12.8%) Bounder diet; and 4) high CP (53.9%), high CL (15.1%) marine finfish diet. Energy: protein ratios (E: P) were 44.6, 45.3, 41.8, and 39.1 W/g.

Survival to 221 d on all diets was 100%. Significant (P < 0.05) differences in growth rates were observed among diets. Final weights were higher for midlevel and high CP diets 3 and 4 (1,051 and 1,013 g) than for low CP diet 1 (873 g). Relative growth rate (RGR, % total increase in weight), specific growth rate (SGR, % increase in body weight/d), and daily weight gain (DWG, g/d) were higher for higher CP diets 3 and 4 (RGR = 223 and 221; SGR = 0.53; DWG = 3.28 and 3.16), than for low CP diet 1 (RGR = 181; SGR = 0.47; DWG = 2.54). There were no significant differences between initial and final whole body protein and fiber content among diets. Lipid and gross energy levels significantly increased (P < 0.0001) in all treatments while moisture levels significantly decreased (P < 0.001).

Although these differences were not significant, feed conversion ratio (FCR = dry weight fed/wet weight gain) was lower for fish given midlevel CP diet 3 (1.49) and high CP diet 4 (1.52) than for those fed low CP diets 1 and 2 (1.60 and 1.62). Protein efficiency ratios (PER = weight gain/weight protein fed) (1.43 to 1.24), apparent net protein retention (ANPR = weight protein gain/weight protein fed) (20 to 25%), and apparent net energy retention (ANER = energy gain/energy fed) (53.3 to 56.8%) were not significantly different among treatments. The midlevel CP (50%), midlevel CL (12%) diet maximized growth rates and was also significantly less expensive per kg fish weight produced ($1.40) than the high CP diet ($1.94) which produced the second highest growth rates. These results demonstrated that wild‐caught black sea bass can be successfully reared in recirculating tanks from juvenile to marketable sizes with high survival and with good feed conversion and growth on commercially prepared diets with a wide range of protein and lipid levels.
Effect of Various Dietary Lipid Levels on Quantitative Essential Fatty Acid Requirements of Juvenile Pacific White Shrimp Litopenaeus vannamei
Authors: González‐Félix Mayra L. , Gatlin Delbert M. , Lawrence Addison L. , Perez‐Velazquez Martin
Published: April 2007

A 6‐wk feeding trial was conducted to evaluate the effect of various dietary lipid levels on quantitative requirements for essential fatty acids (EFA) by juvenile Pacific white shrimp Litopenaeus vannamei. A factorial experiment with three dietary lipid levels (3, 6, and 9%) and three dietary levels (0.5, 1, and 2%) of a mixture of n‐3 highly unsaturated fatty acids (HUFA) was used. An increase in quantitative requirements for EFA with increasing supplementation level of dietary lipid was not demonstrated. Results suggested that this shrimp species appeared to be able to satisfy its n‐3 HUFA requirements when they were supplied at 0.5% of diet; this dietary level may be even lowered. Moreover, depressed growth was observed in shrimp fed diets with the HUFA mixture supplemented at 2%. In addition, the present study showed that increasing the dietary lipid level had an effect on lipid composition of shrimp, by increasing lipid deposition in hepatopancreas and muscle tissue, but without a significant effect on growth.
Effect of Water Exchange Rate on Waste Production in Semi‐Intensive Shrimp Ponds During the Cold Season in New Caledonia
Authors: Lemonnier H. , Martin J. L. M. , Brizard R. , Herlin J.
Published: April 2007

An experiment was conducted in six earthen ponds with 20 shrimp/m2 (Litopenaeus stylirostris) during the cold season in New Caledonia to determine the effect of water exchange rate on characteristics of effluents and pond sediment. The nitrogen budget was established, taking into account the different forms of nitrogen in the water, sediment, feed, and shrimp. Mean water exchange rates ranged from 10 to 23% per day. Increasing water exchange rate did not cause any significant change in the average quality of the rearing environment (water and sediment) during the whole growout period. However, the results showed that increasing exchange rates boosted primary productivity. Compounds produced by the mineralisation and metabolism of organic matter (feces, uneaten feed) were exported as particulate, rather than soluble matter. The nitrogen budget showed that the amount of exported wastes from the pond into the coastal environment was only 40–50% of nitrogen inputs due to nitrogen accumulation in the pond sediments and/or release to the atmosphere. The highest accumulation of dry material, as well as the highest ΔN (concentration of total N at the end of rearing ‐ concentration of total N before rearing), was observed in ponds with the highest WER.
Concentration and Composition of Astaxanthin in Black Tiger Prawn Penaeus monodon Postlarvae Fed Artemia sp. Nauplii or Mauxia Shrimsp Acetes intermedius
Authors: Pan Chih‐Hung , Chien Yew‐Hu
Published: April 2007

Minced Taiwan mauxia shrimp Acetes intermedius, an alternative to brine shrimp Artemia sp. nauplii, has long been used as a principal or supplemental feed in prawn hatcheries in Southeast Asia and India. In this study, black tiger prawn Penaeus monodon postlarvae were fed with frozen brine shrimp nauplii (diet B) or minced Taiwan mauxia shrimp (diet M) for 4 wk to compare their astaxanthin concentration and composition, survival, and growth. Diet B contained two and a half times more total carotenoid (TC) than diet M, with canthaxanthin as a major (79%) carotenoid, but without astaxanthin, a predominant carotenoid in crustaceans. Of its TC in diet M, 55% was β‐carotene and 17% astaxanthin. B‐prawn (postlarvae fed with diet B) had a similar growth rate as M‐prawn and twice the survival rate as M‐prawn. The concentrations of total astaxanthin (TA), free astaxanthin (FA), astaxanthin monoester (MA), and astaxanthin di‐ester (DA) in B‐prawn were all higher than those in M‐prawn. Except for FA, no reduction of TA, MA, or DA concentration during the feeding interval was found in B‐prawn. However, concentrations of TA, FA, MA, and DA in M‐prawn all decreased. TC content of the experimental diets had a greater influence on resulting prawn astaxanthin concentration and composition than carotenoid compositions of the diets.
Effect of Dietary Total Protein and Animal Protein on Growth and Feed Efficiency of Juvenile Channel Catfish Ictalurus punctatus and Their Response to Edwardsiella ictaluri Challenge
Authors: Li Menghe H. , Wise David J. , Manning Bruce B. , Robinson Edwin H.
Published: April 2007

A laboratory study was conducted to evaluate effects of dietary total protein and animal protein source and concentration on growth and feed efficiency of juvenile channel catfish Ictalurus punctutus and their response to Edwardsiellu ictuluri challenge. Eight diets evaluated were: three diets containing either 28, 32, or 36% crude protein with 6% menhaden fish meal and 6% meat and bonehlood meal and five diets containing 32% crude protein with either no animal protein, 68 or 12% menhaden fish meal, or 6% or 12% meat and bonehlood meal, respectively. Twenty channel catfish with an average weight of 6.6 g/fish were stocked into each of forty 110‐L flow‐through aquaria (five aquaridtreatment). Fish were fed to approximate satiation twice daily for 9 wk. Fish in each tank were then exposed to E. ictaluri. There were no differences in feed consumption, weight gain, feed efficiency, and survival before and after challenge among fish fed diets containing 28, 32, or 36% protein with 6% menhaden fish meal and 6% meat and bone/ blood meal. Fish fed a 32% all‐plant protein diet had weight gain and feed efficiency similar to fish fed diets containing 12% menhaden fish meal, but had a higher weight gain than fish fed a 32% protein diet containing 6% meat and bonehlood meal. No significant differences were observed in survival after E. ictuluri challenge among fish fed diets containing the various levels of animal proteins. Results indicate that dietary protein levels varying from 28% to 36% do not appear to affect growth, feed efficiency. and E. icraluri resistance or susceptibility in fingerling channel cattish fed to satiation and raised from approximately 7 to 56 g under laboratory conditions. Data also demonstrate that a 32% all‐plant protein diet can be fed to small fingerling channel catfish without adversely affecting growth, feed efficiency, or resistance to E. ictuluri.
Proximate Composition, Lipid Oxidation, and Sensory Characteristics of Fillets from Rainbow Trout Oncorhynchus mykiss Fed Diets Containing 10% to 30% Lipid
Authors: Chaiyapechara Sage , Liu Kenneth K. M. , Barrows Frederic T. , Hardy Ronald W. , Dong Faye M.
Published: April 2007

This study was conducted to determine the effects of increasing dietary lipid concentrations on fillet characteristics of post‐juvenile rainbow trout. A feeding trial was conducted with fish meal based diets containing 10, 15, 20, 25, or 30% lipid for 24 wk. Menhaden oil was the lipid ingredient. Weight gain was significantly greater in fish fed the 30% lipid diet than in fish fed either 10%, 15% or 20% lipid diets. There were no significant differences in visceral somatic index. Fillet lipid concentration of fish fed the 30% lipid diet (9.2‐g lipid/ 100‐g fillet) was significantly higher (P < 0.05) than fish fed either the 10% or 15% lipid diets (5.8‐ and 6.9‐g lipid/100‐g fillet, respectively). In samples stored for 3 d at 5 C or S wk at ‐20 C, sensory panelists reported that the cooked fillets from fish fed the 30% lipid diet were “more fishy” than fish fed the 15% lipid diet, and preferred the cooked fillets from the 15% lipid treatment over the 30% lipid treatment. Triangle tests and fillet colorimetry showed no significant differences between fillets from fish fed the 15% and 30% lipid diets at any sampling time point. No significant differences in fillet concentrations of thiobarbituric reactive substances were observed among dietary treatments stored at either 5 C or ‐20 C. These results suggest that two main effects of feeding a 30% lipid diet (with fish oil as the lipid source) are a higher lipid concentration in the fillet and a “fishier” aroma compared to fillets from fish fed a 15% lipid diet.
Development of Nursery Systems for Black Sea Bass Centropristis striata
Authors: Stuart Kevin R. , Smith Theodore I.J.
Published: April 2007

Black sea bass (Centropristis striata) are territorial fish and cannibalism is a concern when rearing juveniles in intensive systems. Three studies were conducted to provide information for development of suitable tank nursery systems for juvenile black sea bass (3.6–4.5 cm; 0.8–1.7 g). Studies were performed at the Marine Resources Research Institute, Charleston, SC, using 1.5‐m diameter × 0.8 m deep tanks connected to recirculating seawater systems. The studies examined growth and survival at different stocking densities, selection and utilization of habitats, and, effects of water velocity on positioning and movement of fish. In study 1, fish were stocked at biomass densities of 126.7, 253.3, and 506.7 Wm3 and reared for 56 days with no habitats. No difference in growth was detected although fish reared at the lower densities had significantly lower mortality (mean 7.9%) as compared to those at the highest density (28.0%). At the highest density, cannibalism appeared to be a substantial cause of mortality. In study 2, three habitat types were used, (1) two‐tier structure constructed from plastic grating with 15 mm square openings (volume = 0.015 m3); (2) PVC pipe bundle (volume = 0.004 m3); (3) rock aggregate (volume = 0.008 m3). Of the habitats, the most utilized habitat (62.9%) was the two‐tier layered structure that allowed movement in all directions. The next utilized type was the pipe bundle (25.6%) with the openings inhabited by the largest juveniles in each tank. Overall, a mean of 18.2% of the fish were observed using habitats. Study 3 examined water velocities ranging from 0.01 to 0.12 m/sec. Most fish became concentrated in the tank bottom area having a water velocity in the range of 0.040.09 m/sec. At these velocities there were few aggressive interactions. Smaller fish inhabited the areas outside this velocity range. At the higher velocities, the small fish swam vigorously to maintain their position in the water column. At the low velocities, sporadic incursions of larger fish occurred presumably to attempt to cannibalize or to defend territory. Results from these studies help to define characteristics of nursery systems for rearing juvenile black sea bass.
Changes in Plasma Cortisol, Glucose, and Selected Blood Properties in the Summer Flounder Paralichthys dentatus Associated with Sequential Movement to Three Experimental Conditions
Authors: Sulikowski James A. , Howell W. Huntting
Published: April 2007

To determine the changes in blood chemistry associated with sequential transfer of summer flounder Paralichthys dentatus (320–480 g), 300 hatchery‐reared fish were moved to three different environmental conditions during a 20‐d period. Fish were transferred in progression from a recirculating seawater system (22 ppt, 22.5 C) to a flow‐thru seawater system (31 ppt, 20.0 C), to three small coastal net pens (33 ppt, 15.5 C), and finally to a large open ocean net pen (33 ppt, 16.0 C). For this study, eight random fish were captured at each progressive step (environmental condition), anesthetized (MS222), and bled from the caudal vein (2 mL). Transferred flounder were bled every 12 h for 48 h to collect plasma cortisol and glucose samples. Fish were bled 24 h after transport and every 3 d thereafter for osmolarity, hematocrit, hemoglobin concentration, mean corpuscular hemoglobin content, glucose, cortisol, and the electrolytes Cl‐ Na+, K+ and Ca+. The most significant perturbations to blood chemistry (P < 0.05) occurred within 24 h of initial transfer from the recirculating to flow‐thru seawater systems, suggesting an osmoregulatory rather than handling or transfer related stress. Osmolarity, electrolyte, and hematological parameters fluctuated and then recovered to stable levels by day 8 in the flow‐thru seawater system. However, unlike the initial transfer, successive movement to the coastal and then the open ocean net pens produced transient increases in both plasma cortisol and glucose levels, suggesting a high level of stress associated with extended flounder handling and transfer.