bluuebunny/crossref_metadata_2025 huggingface dataset:
Cryopreservation of Paddlefish Polyodon spathula Milt
Authors: Brown George G. , Mims Steven D.
Published: April 2007

Abstract.— A practical procedure for cryopreserving milt of paddlefish Polyodon sparhula was developed to obtain thawed spermatozoa that would fertilize eggs and permit hatching of normal larvae. Milt was mixed with a cryoprotectant medium containing DMSO (2.4 M) in a ratio of 3:1(milt: medium; final concentration of DMSO 0.6 M), stored in 5.0‐mL freezing straws, and frozen in dry ice (15 min) and then in liquid nitrogen. A total of three replicates were made; the milt of a different male was used in each replicate. Motility of the thawed spermatozoa decreased to 50%‐25% as compared to 100% motility of the fresh (control) spermatozoa. Hatching of paddlefish (16.3 ± 2.2%) from eggs fertilized with thawed spermatozoa was significantly lower (P≤ 0.01) than the hatch rate (90.8 ± 2.5%) for the control. It was suggested that an increase in viable motile spermatozoa to egg would result in better fertilization and hatching of paddlefish.
Evaluation of Dual Injection of LHRHa and the Dopamine Receptor Antagonist Pimozide in Cage Spawning of Channel Catfish Ictalurus punctatus
Authors: Silverstein Jeffrey T. , Bosworth Brian G. , Wolters William R.
Published: April 2007

Abstract.— Control of reproduction in cultured fishes has been improved by the use of gonadotropin releasing hormones (GnRH's) and, in many fishes, the use of dopamine (DA) receptor antagonists. However, little successful use of these treatments has been reported for channel catfish Ictalurus punctatus. This study was conducted to investigate the potential of treatment with a gonadotropin hormone releasing hormone (GnRH) and a dopamine (DA) receptor antagonist to improve cage spawning success in channel catfish. Two and 3‐yr‐old catfish were selected from ponds. All males were injected with des‐Gly10, [D‐Ala6]‐Leuteinizing hormone releasing hormone ethylamide (LHRHa, 50 μg/kg body weight). Females were randomly assigned to the various injection treatments, control (vehicle injected, C), LHRHa only (L), DA receptor antagonist (pimozide) only (P), and LHRHa and pimozide (LP). After injections, one male and one female were paired and placed into 1 m wide × 1.5 m long × 1.2 m deep spawning cages with a metal spawning can. Spawning cans were checked from 1 to 10 d after injection and successful spawning events were recorded. Five trials were conducted between 13 May and 5 June 1998. The LP treatment yielded significantly more spawns than any other treatment (LP, N = 24, 83% > L, N = 25, 44% > C, N = 23, 43 % > P, N= 11, 36%). The greatest promotion of spawning with LP treatment was in the first two induction trials. In the subsequent three trials, differences between treatments were not significant, although LP tre.ated females tended to spawn more frequently. Percent hatch (60.5 ± 3.4%) did not differ between treatments. Treatment of females with LHRHa + pimozide is a potentially useful method for increasing spawning success, particularly early in the spawning season.
Evaluation of Simple Instruments for the Measurement of Blood Glucose and Lactate, and Plasma Protein as Stress Indicators in Fish
Authors: Wells Rufus M. G. , Pankhurst Ned W.
Published: April 2007

Abstract.— Responses of rainbow trout, Oncorhynchus mykiss, to handling and confinement stress were used to validate the efficacy of portable instruments for measuring blood glucose and lactate, and plasma protein. Glucose and lactate increased with time and showed good linear correlation with time after disturbance. The Advantage blood glucose and Accusport™ lactate meters were similarly correlated, except that values were consistently lower than those obtained by established laboratory techniques. Refractometry gave higher plasma protein values than results from biuret reagent but with excellent correlation. These findings indicate a potential role for portable instruments in field and hatchery locations where relative rather than absolute values may be used to evaluate responses to stressors.
Replacement of Fish Meal with Salicornia Meal in Feeds for Nile Tilapia Oreochromis niloticus
Authors: Belal Ibrahim E. H. , Al‐Dosari M.
Published: April 2007

Abstract.— We investigated the use of the halophyte salicornia Sulicornia bigelovii as a replacement for fish meal in feeds containing 35% crude protein for Nile tilapia Oreochromis niloticus. Five isocaloric, isonitrogenous diets were formulated with salicornia meal to replace 0%. 20%. 40%. 60%. and 80% of the fish meal in the feed. Another diet was formulated entirely from salicornia meal. Diets were fed to three replicate groups of tilapia fingerlings (mean initial weight = 0.5 g/fish) for 6 wk in 40‐L aquaria supplied with 22 C well water. Tilapia growth did not differ (P < 0.05) for fish fed diets in which 0%. 20%. or 40% of the fish meal in the diet was replaced with salicornia meal. Weight gain was reduced when fish were fed diets with higher levels of salicornia meal, and growth was slowest for fish fed diets formulated entirely from salicornia meal. Body fat was reduced and body moisture content was increased (P < 0.05) for fish fed diets in which more than 80% of the fish meal was replaced with salicornia meal. We conclude that salicornia meal can replace up to 40% of the fish meal in O. niloticus feeds without affecting growth or body composition.
Sedimentation and Resuspension in Earthen Fish Ponds
Authors: Avnimelech Yoram , Kochva Malka , Hargreaves John A.
Published: April 2007

Resuspension of particles from pond sediment into the water column may be an important nutrient transfer mechanism in aquaculture ponds. However, the magnitude of sediment re‐suspension cannot be determined directly because sediment traps collect particles settling from the water column as well as those re‐suspended from the pond bottom. We developed a dilution analysis method to differentiate the magnitude of the two particle source fluxes based upon the concentration of soil‐derived elements (Si, Al, and Fe) and water‐derived elements (C, N) in material collected by sediment traps placed in earthen ponds. Estimated organic C sedimentation from feed residues and algae was compared with trapped organic C as an independent and approximate measure of resuspension. Resuspension fluxes based independently on analyses of three soil‐derived elements and on the estimation of expected C sedimentation were similar and accounted for 60–90% of the total solids flux (121–2,676 g/m2 per d) in most ponds sampled. The proportion of total flux that was derived from resuspension in ponds stocked with common carp Cyprinus carpio and tilapia Oreochromis spp. was modeled as a hyperbolic function of fish size and density, with a threshold fish size of 200–300 g. Resuspension flux was conservatively estimated to be equivalent to the daily suspension of a few mm of the pond bottom. These results indicate that sediment resuspension is a major process in carp and tilapia ponds, suggesting that the exchange of nutrients between the sediment and overlying water is intensive.
Factors Affecting Metabolism of Commercial Channel Catfish Ponds as Indicated by Continuous Dissolved Oxygen Measurement1
Authors: Hargreaves John A. , Steeby James A.
Published: April 2007

Continuous dissolved oxygen (DO) measurements were analyzed to evaluate the rates of pond metabolic processes related to productivity and respiration in three commercial catfish ponds in northwest Mississippi. Multiple regression models were constructed to assess the relative importance of various forcing functions on indices of net primary productivity (NPP) and whole pond respiration (WPR), duration of automated aeration, and DO concentration below various threshold values. Water temperature, solar radiation, wind run, cumulative feed, and lagged values of these parameters were considered as forcing functions. Generally, NPP and WPR were most strongly affected by water temperature and only weakly related to solar radiation. The duration of nightly aeration was also strongly related to water temperature, although 10‐d cumulative feed was an important predictor in one pond. The best predictors of duration of DO below certain threshold values were NPP, WPR and wind run, the importance of which varied depending upon the pond and the threshold value considered. Change in feeding rate from one day to the next was inversely related to feeding rate on the previous day. The results of this analysis suggest that NPP and WPR rates, and the duration of required nightly aeration in commercial catfish ponds are controlled by factors not amenable to practical management control.
Effect of Partial and Total Replacement of Fish Meal on Growth and Body Composition of Sunshine Bass Morone chrysops×M. saxatilis Fed Practical Diets
Authors: Webster Carl D. , Tiu Laura G. , Morgan Ann M. , Gannam Ann
Published: April 2007

With the increasing emphasis to replace fish meal (FM) with less expensive protein sources in aquaculture diets without reducing weight gains, an 8‐wk feeding trial was conducted with juvenile (15 g) sunshine bass Morone chrysops×M. saxatilis) to evaluate growth and body composition when fed diets with different levels of FM (0, 7.5, 15, and 30%). Six practical floating diets were formulated to contain 40% protein and similar energy levels, with various percentages of FM, meat‐and‐bone meal (MBM), soybean meal (SBM), poultry by‐product meal (PBM), and/or distillers grains with solubles (DGS). Ten fish were stocked into each of 24 110‐L aquaria and were fed twice daily ad libitum (0730 and 1600 h). At the conclusion of the feeding trial, final weights of fish fed diet 2 (0% FM, 29% SBM, 29% MBM, and 10% DGS), diet 3 (0% FM, 32% SBM, and 28% PBM), diet 5 (15% FM and 44% SBM), and diet 6 (30% FM and 26% SBM) were not significantly different (P > 0.05) and averaged 72 g. However, final weights of sunshine bass fed diet 1 (0% FM, 30% SBM, and 31% MBM) and diet 4 (7.5% FM and 54% SBM) were significantly lower and averaged 55 g. Specific growth rate (SGR) of sunshine bass fed diet 4 was significantly lower (2.14) than fish fed diet 2 (2.70), diet 3 (2.80), diet 5 (2.68), and diet 6 (2.84), while feed conversion ratio (FCR) of fish fed diet 4 was significantly higher than sunshine bass fed diets 2, 3, 5, and 6. Carcass (fish were decapitated) composition of sunshine bass fed diet 4 had a significantly higher percentage of moisture (70%) and protein (54% on a dry‐matter basis) than fish fed all other diets. Percentage lipid was similar among fish fed all diets and averaged 41% (dry‐matter basis).

Results from the present study indicate that diets in which all of the FM is replaced with a combination of animal‐ and plant‐source proteins can be fed to sunshine bass without adverse effects on weight gain, growth rate, and body composition. Further feeding trials are needed to refine diet formulations used in the present study and should be conducted in aquaria and ponds.
Effect of Astaxanthin on the Pigmentation of Goldfish Carassius auratus
Authors: Paripatananont Tippawan , Tangtrongpairoj Jirasak , Sailasuta Achariya , Chansue Nantarika
Published: April 2007

The optimal dosage of astaxanthin for goldfish Carassius auratus was determined by feeding a series of diets containing 0, 25, 50, 75, and 100 mg of astaxanthin/kg of diet for 4 wk. The pigmentation on fish skin was measured by visual assessment against a color chart and by counting chromatophores produced in the dermis layer of fish skin. Both criteria showed that 36–37 mg/kg astaxanthin was the optimal dosage to stimulate fish color. A 4‐wk observation after this experiment demonstrated that fish color stimulated by dietary astaxanthin was stable in its intensity. Therefore feeding astaxanthin could be a suitable way for goldfish producers to stimulate color among fish grown in an algae‐free environment. The survival rate of fish fed diets with astaxanthin was significantly higher than fish fed diets without astaxanthin. However, there was no significant effect of astaxanthin on fish weight gain.
Effect of Heated and Unheated Fish Silage as a Protein Source in Diets for Abalone Haliotis fulgens
Authors: Viana Maria Teresa , Guzman Jose Manuel , Escobar Roberto
Published: April 2007

Both unheated (US) and heated (HS) fish silage were evaluated as sole dietary protein sources in an artificial diet for the culture of juvenile abalone Haliotis fulgens. The fish silage was heated to reduce the level of hydrolysis and thereby increase the availability of nutrients. After 140 d of culture, growth rates of abalone fed the US‐ and HS‐containing diets were 16.4 and 19.8 μm/d and were not significantly different despite greater leaching of protein and carbohydrate in the US‐containing diet. Growth rates achieved with the US‐ and HS‐containing diets were significantly lower than that achieved by feeding a commercially available diet used as a reference diet. Abalone that were fed the US‐ and HS‐containing diets were then switched to a diet in which two‐thirds of the total amount of silage was replaced with fishmeal. At the termination of the experiment, day 217, the abalone originally fed the US and HS diets had composite growth rates of 24.3 and 23.5 μm/d, while abalone that continued to be fed the commercial diet had a growth rate of 18.6 μm/d. Stability of the dry matter of the diets was not related to the level of protein leaching. Fish meal out performs fish silage as a dietary protein source for abalone. However, growth rates achieved still fall short of that needed to achieve a market size product within a 2‐yr period of growth.
Effect of Luteinising Hormone‐Releasing Hormone Analogue and Human Chorionic Gonadotropin on Ovulation, Plasma and Ovarian Levels of Gonadal Steroids in Greenback Flounder Rhombosolea tapirina
Authors: Poortenaar Carolyn W. , Pankhurst Ned W.
Published: April 2007

Female greenback flounder Rhombosolea tapirina were treated with either des Gly10 [D‐Ala6] LHRH ethylamide (LHRH‐a) at 50 or 100 pg/kg intraperitoneal injection (ipi), LHRH‐a cholesterol pellet (LHRH‐a pellet) 100 μg/kg implanted intraperitoneally, or human chorionic gonadotropin (hCG) 1,000 IU/kg ipi. Treatment with hCG, LHRH‐a (50 μg/kg) ipi and LHRH‐a pellet increased the total number of ovulations above control levels. LHRH‐a (100 μg/kg) ipi was not consistently more effective than the control and both LHRH‐a (50 μg/kg) ipi and LHRH‐a pellet induced more ovulations than LHRH‐a (100 μg/kg) ipi. Of those fish that ovulated, most ovulated more than twice, and most ovulations occurred at daily intervals. Oocyte diameters increased and oocyte stage advanced significantly in response to all exogenous hormone treatments. This was accompanied by increases in plasma and ovarian levels of 17β‐estradiol (E2, and in most cases, plasma and ovarian levels of testosterone (T). Plasma and ovarian levels of 17,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20βP) were not consistently elevated in association with reproductive events.
Induction of Spawning in the Sea Cucumber Holothuria scabra (Echinodermata: Holothuroidea)
Authors: Morgan Andrew David
Published: April 2007

With the advent of sea cucumber aquaculture in the South Pacific region, a reliable method is needed to induce large numbers of animals to spawn in captivity. Broodstock of the sea cucumber Holothuria scabra, collected from Stradbroke Island, Moreton Bay (27°90′N, 153°24′E) Australia, during the reproductive season from October to January, were used in spawning trials. During the 1997–1998 summer between one to five weeks of captivity, 100% of animals were induced to spawn in four trials at dusk on or close to a new or full moon, using nine males and nine females contained in a Reln tank and 30 cm of filtered sea water, using a 3–5 C temperature shock. H. scabra was induced to spawn in small numbers during the 1996–1997 summer despite a marked degree of weight loss, and all animals spawned during 1997–1998 with minimal loss of weight. The difference in the number of spawned eggs between animals of similar size and mean numbers of spawned eggs in consecutive trials decreased the longer animals were held in captivity before spawning. The hatch rate of eggs was reduced significantly for broodstock held for more than one month. Hatch rate and numbers of spawned eggs are important indicators of egg viability of broodstock maintained in captivity for an extended period.
Differences in Growth in Blue Catfish Ictalurus furcatus and Channel Catfish Z. punctatus Fed Low‐Protein Diets With and Without Supplemental Methionine and/or Lysine
Authors: Webster Carl D. , Tiu Laura G. , Morgan Ann M. , Gannam Ann L.
Published: April 2007

Three feeding experiments were conducted to evaluate growth and body composition in blue caffish Ictalurus furcatus or channel caffish I. punctatus when fed diets containing 22% protein with or without supplemented methionine and/or lysine. All experiments were conducted in 110‐L aquaria that were part of a recirculating system. In Experiment 1,15 juvenile blue catfish (2.7 g) were randomly stocked into aquaria and fed one of three diets containing different (22%, 27%, and 32%) percentages of protein. Fish were fed twice daily to excess for 10 wk. In Experiment 2, juvenile blue catfish (5.4 g) were randomly stocked into aquaria and fed one of six diets containing either 22% (diet 1) or 32% (diet 2) protein. The diet containing 22% protein (diet 1) had either 0.3% crystalline L‐methionine (diet 3), 0.4% crystalline L‐lysine (diet 4), or 0.3% L‐methionine + 0.4% L‐lysine (diet 5) added. A sixth diet was formulated to contain 32% protein and 0.2% crystalline L‐methionine. Fish were fed in excess for 12 wk. In Experiment 3, juvenile channel caffish (10.3 g) were stocked and fed diets 14 from Experiment 2, twice daily in excess for 8 wk.

In Experiment 1, after 10 wk, final individual weight, weight gain (%), and specific growth rate (SGR) of blue catfish fed diets containing three protein levels were not significantly different (P > 0.05) and averaged 12.9 g, 378%, and 2.2%/d, respectively. Fish fed the diet containing 27% protein had higher (P < 0.05) whole‐body protein (65.4%) compared to fish fed diets containing either 22% or 32% protein. In Experiment 2, final weight, weight gain (%) and SGR of blue catfish were not significantly (P > 0.05) different among diets and averaged 24.7 g, 355%, and 1.8%/d, respectively. Percentage whole‐body protein and lipid were not significantly (P > 0.05) different between fish fed diets containing 22% or 32% protein. In Experiment 3, channel caffish fed a diet containing 32% protein had significantly (P > 0.05) higher final individual weight, weight gain (%), and SGR compared to fish fed diets containing 22% protein, with and without supplemental methionine or lysine.

Results indicate that blue catfish may be able to utilize a diet with 22% protein, and that addition of crystalline methionine and/or lysine did not improve growth. However, channel catfish grown in aquaria did not appear to have similar growth when fed a diet containing 22% protein compared to fish fed 32% protein, even when supplemental methionine or lysine was added. Further research on blue catfish and the use of a low‐protein diet (22% protein) needs to be conducted in ponds.
Growth and Feeding Level in Pre‐Weaning Tambaqui Colossoma macropomurn Larvae
Authors: Sevilla Adrián , Günther Jorge
Published: April 2007

The relation between growth, feed utilization and feed ration was assessed during the first 15 feeding days in Colossoma macropomum larvae fed with Artemia nauplii. Maintenance, optimum and maximum feeding rations (1.23; 5.48 and 27.2% body weight/d, dry feed, respectively) and feed conversions (0.4 and 0.78 optimum and maximum, respectively) were determined. At maximum feeding the larvae grew 2.6 times faster that at optimum feeding, but the feeding costs increased 1.94 times. Two commonly used growth rates (specific growth rate, SGR and coefficient G) were compared for the modelling of larval growth. The maximum specific growth rate (SGR, growth rate at maximum feeding) remained relatively constant during the first 15 d of feeding and is thus much more adequate to model the growth of tambaqui larvae, than the coefficient G, which increased more than four times in this period.
Effects of Water Velocity on Growth Performance of Juvenile Japanese Flounder Paralichthys olivaceus
Authors: Ogata Hiroshi Y. , Oku Hiromi
Published: April 2007

Critical swimming speed (Ucrit) of juvenile Japanese flounder Paralichthys olivaceus with 12.5‐cm body length was determined to be 1.8‐body lengthkec. A feeding trial was conducted to investigate the effects of water velocity on growth and other nutritional parameters of juvenile flounder (initial mean body weight: 5.7 g/fish), which is a sedentary species. The fish were raised in three water velocities, < 0.3 body length/sec (control), 0.9 body length/sec (slow) and 2.1 body length/sec (moderate), for 8 wk. Over the course of the feeding trial, the weight gain of the control, slow and moderate groups of fish were. 634%. 671% and 564%. respectively (significant between slow and moderate groups). A second order polynomial suggested that the optimum water velocity occurred at about 1.0 body length/sec. The feed efficiency of the moderate group (1.48) was significantly lower than those of the control (1.56) and slow (1.56) groups, while there were no significant differences in feed intake (1.72–1.75% of wet biomass) among the treatments. Water velocity did not affect the proximate composition of the whole body; however, rearing the fish at the moderate water velocity did slightly but significantly reduce protein retention. Lipid content of fin muscles was significantly different among the treatments: control (14.9%), slow (17.6%) and moderate groups (11.6%). Unlike salmonids, water current does not seem effective for improving growth and feed efficiency in juvenile Japanese flounder.
Fertilization and Development of Eggs of the Sea Urchin Lytechinus variegatus Maintained on an Extruded Feed
Authors: George Sophie B. , Lawrence John M. , Lawrence Addison L. , Ford John
Published: April 2007

Sea urchin eggs are used extensively as models for studies in developmental and molecular biology. Developing aquaculture techniques and facilities for sea urchins would facilitate their use for this purpose and for production of young sea urchins for stock enhancement. A basic requirement for the aqua‐culture of sea urchins is the availability of a feed that predictably produces eggs of a consistent, high quality. We tested an extruded feed with Lyrechinus variegatus for this purpose. Lytechinus variegatus (mean horizontal diameter 55 mm, 75 g wet weight) were collected in April 1998. Nine individuals were maintained in each of four aquaria with closed, recirculating filtered sea water. They were fed approximately 1 g extruded feedindividual per week. All feed was consumed. The mean weight of the sea urchins changed little with this feeding regime. The sea urchins spawned spontaneously on a monthly basis during water changes. Four females in February and one in March were spawned by injection with potassium chloride. Fertilization was 99–100% successful in each case. Egg diameters from these spawnings and a spontaneous spawning in April ranged from 102 × 6 to 128 × 1 μm. Gastrulation occurred in <20 h and metamorphosis after 22 to 37 d. Newly metamorphosed juveniles ranged in size from 435 × 38 to 473 × 56 μm. Egg size, larval size, the chronology of embryonic and larval development, and size of newly metamorphosed juveniles are similar to those obtained from field individuals reported in the literature. These results indicate that a predictable production of high quality eggs by sea urchins under controlled conditions in the laboratory with a prepared feed is feasible.
Cost Analysis for Integrating Cryopreservation into an Existing Fish Hatchery
Authors: Caffey Rex H. , Tiersch Terrence R.
Published: April 2007

Fish sperm cryopreservation is documented by a large body of technical research. However, there are no reports of the economic requirements for using this technology in aquatic species. This study establishes a generic analysis of the investment and operating costs required to integrate sperm cryopreservation into existing fish hatcheries and can serve as a template for implementation of cryopreservation programs. Equipment and supplies were identified in a species‐independent description of sperm cryopreservation, and capital and operating costs were documented for private and public hatcheries at three production capacities (3,000, 6,000, and 9,000 0.5‐mL straws). Compared to public hatcheries, investment costs were found to he 70% higher, and operating costs 20% higher for private hatcheries due primarily to interest on borrowed capital. Equipment costs were dependent on the scope of work. Investment in required equipment incurred costs of $5,460 to $10,458 (public) or $9,497 to $18,190 (private), depending on production level. Purchase of optional research equipment increased initial investment by 300% without increasing output. Per unit costs decreased at higher production levels for all scenarios, but greater economies of scale were associated with private research hatcheries. Production costs ranged between $6.13 and $1.86 per straw (private), to $1.59 to $1.18 per straw (public). Increased commercialization is expected to occur as research protocols for fish sperm cryopreservation are applied in the private sector and markets for cryopreserved sperm are established.
Response of Largemouth Bass Micropterus salmoides to Dietary Supplementation of Lysine, Methionine, and Highly Unsaturated Fatty Acids
Authors: Coyle Shawn D. , Tidwell James H. , Webster Carl D.
Published: April 2007

Abstract.— A 12‐wk feeding trial was conducted in aquaria with juvenile (36.0 ± 1.2 g) largemouth bass Microptents salmoides to examine the effects of dietary supplementation of methionine, lysine, and long‐chain polyunsaturated fatty acids (PUFA) on growth, feed conversion and body composition. Diets were formulated to increase dietary concentrations of methionine. lysine, and PUFAs to match levels found in whole body samples of largemouth bass. The control diet was formulated similar to diets previously tested for largemouth bass. Diets 2 and 3 were similar to the control diet hut were supplemented with 2% lysine and 1% methionine, respectively. Diet 4 was formulated to increase PUFAs, especially docosahexaenoic acid (DHA) (22:6n‐3), by replacing menhaden fish oil with squid oil. Fish were fed all they would consume in 10 min, twice daily. At harvest, there were no statistically significant differences (P > 0.05) in average individual weight or specific growth rate (SGR) among fish fed the four diets. The feed conversion ratio (FCR) of largemouth bass fed the diet supplemented with methionine (1.7) was significantly lower (P≤ 0.05) than fish fed the control diet (2.5). Fish fed the diet high in PUFA had significantly lower (P≤ 0.05) whole body lipid levels and significantly higher (P≤ 0.05) protein levels than fish fed the other three diets. These data indicate that the control diet in this study likely contained sufficient lysine, methionine and PUFA to meet the requirements of largemouth bass; however, additional methionine may improve feed conversion efficiency, and increased levels of PUFAs or other factors in squid oil may have a significant impact on body composition.
Correlation Between Two Size Classes of Pacific White Shrimp Litopenaeus vannamei and Its Potential Implications for Selective Breeding Programs
Authors: Argue Brad J. , Arce Steve M. , Moss Shaun M.
Published: April 2007

Abstract.— The correlation between market weight (20–25 g) and broodstock weight (> 35 g) in Pacific white shrimp Litopenaeus vannamei has not been determined. Breeders may assume that the largest brood‐stock shrimp were also the largest market shrimp. In this study, 120 market shrimp were individually tagged and grown to broodstock in an earthen pond. There was a significant relationship between market and broodstock weight (P < 0.001) but it was not highly correlated (r = 0.42). There was no correlation between market weight and post‐market weight gain (P= 0.477; r= 0.08). Of the largest 20 broodstock, only seven were among the top 20 at market weight. If the goal of a breeding program is to select the fastest growing individuals to market, shrimp should be individually selected at market weight and not as broodstock.
Optimal Stocking Density for Juvenile Winter Flounder Pseudopleuronectes americanus
Authors: Fairchild Elizabeth A. , Howell W. Huntting
Published: April 2007

Abstract.— A 12‐wk experiment was conducted to test the effects of 50, 100, 200, and 300% stocking densities (ventral fish area to bottom tank area ratio) on growth, survival, and aggressive behavior in 2‐moold juvenile winter flounder Pseudopleuronectes americanus. Over the course of the experiment, there were no differences (P > 0.05) in growth between treatments at any given week. Survival decreased in all treatments over time, however, proportionately more fish died in the high (200 and 300%) density treatments. At the end of 12 wk, the 300% treatment had significantly lower survival (P < 0.05). There were no differences in the degree of caudal fin damage between any of the treatments (P > 0.05) suggesting that aggressive behavior. such as fin nipping, was not affected by stocking density. However, fish size was inversely related to caudal fin damage. When fish were sorted by length, the two smallest size categories (<2 cm and 2‐3 cm) suffered the greatest fin nipping compared to each other (P < 0.001) and all larger size categories (P < 0.001). These results indicate that 50 to 300% stocking densities do not affect growth or aggressive behavior in juvenile winter flounder. Although survival was affected by density, the final yield (weight per treatment) at higher densities was still greater than at lower densities. Our hatchery recommendations are to stock at ≥200% but to monitor fish health carefully. Size grading should be employed to minimize aggression between fish size classes.
The Effect of Constant and Fluctuating Temperatures on the Confinement‐induced Plasma Cortisol Stress Response in Channel Catfish lctalurus punctatus
Authors: Davis Kenneth B. , Simco Bill A. , Li Menghe H. , Robinson Edwin
Published: April 2007

Abstract.— Initial and confinement‐induced changes of plasma cortisol were measured in channel catfish Ictalurus punctatus acclimated to upper and lower constant temperatures for each season, a spring/fall diurnal pattern between 15 and 26 C, and a summer diurnal pattern between 24 and 35 C. In diurnal treatments, temperature changes were achieved in 10 h and held constant for 2 h before reversing the temperature. Fish held in the spring/fall pattern or at a constant temperature of 15 or 26 C revealed no plasma cortisol concentration differences due to acclimation temperature, but hormone concentrations in all groups increased by about 4.5 fold following a 2‐h confinement. Fish held on a summer pattern had differences in both the initial cortisol samples and those measured after confinement. Acclimation to a constant 35 C resulted in significantly higher initial cortisol concentrations, but these levels did not increase following confinement. The inability of the fish held at 35 C to respond to the confinement was thought to be due to the constant thermal stress, resulting in an inadequate interrenal reserve. Physiological consequences due to the diurnal physiochemi‐cal cycling in ponds needs further attention.
Effects of Dietary Lipid and Energy to Protein Ratio on Growth and Feed Utilization of Juvenile Mutton Snapper Lutjanus analis Fed Isonitrogenous Diets at Two Temperatures
Authors: Watanabe Wade O. , Ellis Simon C. , Chaves Juan
Published: April 2007

Growth and feed utilization of juvenile, hatchery‐reared mutton snapper Lutjanus analis (mean weight = 12.2 g) were compared for 40 d in laboratory aquaria on four isonitrogenous diets (45% crude protein) of varying lipid content (6, 9, 12 and 15%) with energy:protein ratios (E: P; kJ/g protein) of 33.9, 36.3, 38.8, and 41.2, respectively. Growth on these diets was compared under temperatures of 25 and 30 C. Final weights (Wtr) and specific growth rates (SGR) were higher (P < 0.05) at lower dietary E: P ratios of 33.9 and 36.3 (Wtr= 20.3–22.0 g; SGR = 1.25–1.35%/d) than at E:P ratios of 38.8 and 41.2 (Wtr= 17.2‐17.7 g; SGR = 0.84–0.85%/d). Growth at 30 C (Wtr= 21.5 g, SGR = 1.35%/d) was higher (P < 0.05) than at 25 C (Wtr= 17.3 g; SGR = 0.82%/d). Feed consumption (FC) was higher (P < 0.05) at a dietary E: P ratio of 33.9 (1.57%/d) than at 36.3 (1.27%/d) or 38.8–41.2 (0.89–0.98%/d). Growth was highly correlated (P < 0.01) to E: P ratio and to feed consumption. Feed conversion ratio (FCR = 2.17–3.98), protein efficiency ratio (PER = 0.58–1.03) and apparent net protein retention (ANPR = 15.8–20.0%) were not significantly (P > 0.05) affected by dietary E: P ratio. Apparent net energy retention (ANER) was higher (P < 0.05) at E: P ratios of 33.9 and 36.3 (9.50–9.98%) than at E: P ratios of 38.8 and 41.2 (7.15–7.10%). Feed utilization parameters were significantly (P < 0.05) better at 30 C (FC = 1.36%/d; FCR = 2.6; PER = 0.88; ANER = 10.2%) than at 25 C (FC = 1.03%/d; FCR = 3.38; PER = 0.69; ANER = 6.72%), with the exception of ANPR (17.0–17.8%). Maximum growth and energy retention in juvenile mutton snapper using a diet containing 45% crude protein was obtained at dietary lipid levels of 6–9% and E: P ratios of 33.9–36.3 kJ/g protein. Studies which determine optimum protein levels and the effects of reducing E: P ratios below 33.9 kJ/g are needed to improve feed conversion and growth.
Biochemical Changes in Freshwater Prawn Macrobrachium rosenbergii During Larval Development
Authors: Roustaian Paymon , Kamarudin Mohd Salleh , Omar Hishamuddin Bin , Saad Che Roos , Ahmad Mansor Haji
Published: April 2007

Abstract.— Quantitative changes in the protein, lipid and carbohydrate were studied in the early larval stages of developing freshwater prawn Macrobrachium rosenbergii reared under fed and starved conditions to understand the relative importance of these nutrients in energy metabolism of the growing larvae. Larvae obtained from several females were stocked into three 250‐L tanks at a density of 30 larvae/L. The feeding regime consisted of newly hatched Artemia nauplii. Protein was always the major organic constituent followed by lipids and then carbohydrates of both fed and starved larvae. Protein levels of both fed and starved larvae increased during development, suggesting an important role in morphogenesis. The decline of lipid during the larval growth that was more rapid for starved larvae, suggests a probable utilization of lipid as the major metabolic source of energy. Carbohydrates formed less than 5 and 2.4% of the larval dry weight of fed and starved larvae, respectively, suggesting their limited role in larval metabolism.
Feeding Frequency Affects Growth, Not Fillet Composition, of Juvenile Sunshine Bass Morone chrysops×M. saxatilis Grown in Cages
Authors: Webster Carl D. , Thompson Kenneth R. , Morgan Ann M. , Grisby Ebony J. , Dasgupta Siddhartha
Published: April 2007

Abstract.— In an effort to feed sunshine bass Morone chrysops×M. saxatilis efficiently, promote optimal growth, and reduce labor costs associated with feeding, sunshine bass were grown in cages and fed one of four feeding frequencies: once/d, twice/d, once every other day (I X/EOD), and twice every other day (2X/EOD) for 21 wk. Juvenile sunshine bass were fed a commercial floating diet containing 40% protein and 11.5% lipid. One hundred fish were hand‐counted and stocked into each of 12 3.5‐m3 cages with three replications per treatment. At the conclusion of the study, percentage weight gain of sunshine bass fed twice/d was significantly (P < 0.05) higher (1,850%) compared to fish fed all other feeding frequencies. Specific growth rate (SGR) of fish fed twice/d was significantly higher (2.1%/d) compared to fish fed all other feeding regimes, while fish fed once/d had a higher SGR (2.0%/d) compared to fish fed I X/EOD (1.6%/d) and 2X/EOD (1.8%/d). Percentage survival was not significantly different (P > 0.05) among all treatments and averaged 70.4%r. Feed conversion ratio (FCR) of fish fed twice/d was significantly higher (2.40) compared to fish fed all other feeding regimes. Percentage fillet weight of fish fed twice/d was significantly higher (27.8%) compared to all other treatments. Percentage moisture, protein, lipid, and ash in fillet were not significantly different among all treatments and averaged 75.7%, 19.4%, 3.5%, and 1.2%n, respectively (wet‐weight basis). Based upon data from the present study, it appears that producers growing juvenile sunshine bass in cages may want to feed fish twice daily. This feeding regimen allows for higher growth rates, without adverse effects on body or fillet compositions. However, economic analysis needs to be conducted to determine if feeding twice/d is profitable.
Voluntary Spawning, Early Development, and Completion of the Life Cycle of Spotted Sand Bass Paralabrax maculatofasciatus in the Laboratory
Authors: Martínez‐Diaz Sergio F. , Martínez‐Pecero Rodolfo , Rosales‐Velázquez Martin O. , Alvarado‐Castillo Reyna , Perez‐Espana Horacio , Tucker John W.
Published: April 2007

Abstract.— Spawning behavior and development of spotted sand bass Paralabrax maculatofasciatus were studied in the laboratory. Captive fish (15–20 cm standard length) spawned in 100‐L aquaria at 24 C and 35 ppt salinity with a controlled photoperiod (13 h light: 11 h dark). Distinct courtship coloration and displays were observed. Courtship began near noon and continued all afternoon. Spawning occurred toward the surface during late afternoon. Development from fertilization to 3 d after hatching is described. Hatching occurred in 24–25 h at 24 C. Larvae were reared in 100‐L aquaria with microalgae, rotifers, and Artemia. First feeding occurred 3 d after hatching, and 5.3% survival was obtained at 17 d (4.1‐mm mean notochord length, 1.7–5.5 mm range). On a diet of minced clams and fish, first maturity was reached at 7.5 mo (19.5 g mean weight, 8.3–37.9 g range and 90 mm mean standard length, 66–116 mm range).
Analysis of Catfish Pricing and Market Dynamics: The Role of Imported Catfish
Authors: Quagrainie Kwamena K. , Engle Carole R.
Published: April 2007

The producer price of catfish is becoming relatively unstable compared to the trend in previous years, necessitating the need for a complete analysis of catfish pricing and market dynamics. An understanding of the price determination mechanisms in the catfish market and the relationships between producer price, domestic processed price, and import price are important because price variability can result in significant financial losses to the domestic catfish industry. This study used a cointegration procedure to examine the long‐run relationships between domestic prices of catfish and imported price. Results from unit root and cointegration tests suggest that there is a long‐run equilibrium relationship between pairs of these prices. Results from Granger causality tests and error‐correction model estimations suggest that the market for domestic frozen fillets plays a significant role in the price determination of imported catfish. A similar relationship is found between producer price and frozen fillet price. Some significant measures that were estimated include a frozen fillet‐producer long‐run price transmission elasticity of 0.162, a frozen fillet‐imported fillet long‐run price transmission elasticity of 3.56, and a producer‐frozen fillet short‐run price transmission elasticity of 0.322. High levels of fillet prices appear to have influenced the level of catfish imports. As long as distributors and restauranteurs do not see a basis for paying a premium for U.S. catfish products, they will continue to purchase the lower‐priced imported catfish and consequently imports will continue to increase.
Economic Optimization of Shrimp Farming in Honduras
Authors: Valderrama Diego , Engle Carole R.
Published: April 2007

A profit‐maximizing linear programming model with a risk programming component was developed to identify sets of optimal management strategies and outline an annual schedule of production activities for shrimp farming in Honduras. A database of 912 complete pond production records was used to define technical relationships between stocking density and survival and growth rates and to develop net return coefficients for the mathematical model. Separate matrices were developed for three farm‐size scenarios to account for economies of scale. Results indicated that, in spite of recent viral epizootics, shrimp farming continues to be a profitable economic activity. Stocking density was found to have a negative effect on growth rate, but not on survival rate. As a consequence, low and intermediate stocking rates were most commonly selected, but high stocking densities were recommended in certain periods of the dry season. Results demonstrated some economic advantages of reducing the traditional levels of water exchange with supplemental aeration. The risk programming analysis indicated that the selection of low and intermediate stocking rates resulted in overall annual risk levels that were relatively low.
Essentiality of Dietary n‐3 Highly Unsaturated Fatty Acids in Juvenile Japanese Flounder Paralichthys olivaceus
Authors: Kim Kyoung‐Duck , Lee Sang‐Min , Park Huem Gi , Bai Sungchul C. , Lee Yoon‐Ho
Published: April 2007

This study was conducted to confirm the essentiality of dietary n‐3 highly unsaturated fatty acids (n‐3 HUFA) and to investigate the effects of dietary lipid sources on growth performance, liver, and blood chemistry in juvenile Japanese flounder. Three replicate groups of fish (average weighing 3.0 g) were fed experimental diets containing lauric acid ethyl ester, soybean oil, soybean and linseed oils mixture, and squid liver oil as lipid sources for 13 wk. No significant difference was observed in survival among all groups (P >0.05). Weight gain, feed efficiency and protein efficiency ratio of fish fed the squid liver oil diet containing high n‐3 HUFA level were significantly higher than those of fish fed the other diets (P 0.05). Saturated and monounsaturated fatty acids of liver polar and neutral lipid fractions in fish fed the diet containing lauric acid tended to increase compared to those of the other groups. Fish fed the diets containing soybean and/or linseed oils, which contained high contents of 18:2n‐6 and 18:3n‐3, respectively, showed the highest contents of 18:2n‐6 and 18:3n‐3 in both lipid fractions of the liver (P 0.05). Significantly higher content of n‐3 HUFA was observed in both lipid fractions of the liver from fish fed the diet containing squid liver oil than for fish fed the other diets (P 0.05). Total cholesterol, glucose, and glutamic‐oxaloacetic acid transaminase in plasma were significantly affected by dietary lipids (P 0.05). Histologically, the liver of fish fed the diet containing squid liver oil had a clear distinction between nuclear and cytoplasm membranes; however, cytoplasm of fish fed the diets containing lauric acid and soybean oil was shrunken, and the hepatic cell outline was indistinguishable. It is concluded that the dietary n‐3 HUFA is essential for normal growth, and that the dietary lipid sources affect growth performance, liver cell property, and blood chemistry in juvenile Japanese flounder.
A Qualitative and Quantitative Approach to Determine the Optimum Combination of Feeding Stimulants for Striped Bass Morone saxatilis Using an Agar Gel Carrier
Authors: Papatryphon Elias , Soares Joseph H.
Published: April 2007

A series of experiments was conducted to determine the optimum combination of previously identified feeding stimulants (FS), namely L‐alanine (Ala), L‐serine (Ser), inosine‐5′‐monophosphate (IMP), and betaine (Bet), for striped bass Morone saxatilis. Three experiments were conducted to determine the optimum combination of FS using an agar gel matrix as a carrier. In the first experiment a 24 factorial experiment was conducted to test all possible combinations of the four FS at two levels, 0 and 0.1 M. Significant interactions between the FS were found, suggesting the complexity of gustatory stimulation and palatability. In the second experiment a 4 × 6 factorial design was employed to test each FS alone and at concentrations ranging from 0 to 8% in order to determine the minimum level at which maximal stimulation is achieved. The results suggest that there is no significant improvement in feed intake beyond the 1 % level of supplementation for all the FS. In addition, Ala produced a significantly greater response compared to all other FS. In the last experiment, a modified single factor method was used to estimate the optimum levels for each FS in a mixture. The range of the concentrations tested was 0–1% of the agar gel for each FS. Combining all four compounds yielded maximal stimulation. The levels of each compound in the final optimum combination of FS were: Ala, 0.4; Ser, 0.6; Bet, 0.4; and IMP, 0.3% of the agar gel.
Pharmacokinetics of Dietary 13C‐Labeled Docosahexaenoic Acid and Docosapentaenoic Acid in Red Sea Bream Chrysophrys major
Authors: Tago Akio , Teshima Shin‐Ichi
Published: April 2007

The objectives of this study were to investigate: 1) the pharmacokinetics of dietary docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA) using 13C‐labeled fatty acids; 2) the interorgan transport of DHA in the red sea bream by monitoring the DHA level of several organs; and 3) the relationship between the plasma DHA level and optimum dietary DHA level in the plasma of the red sea bream Chrysophrys major. For this purpose, a mixture of 38.5% of [13C]DHA, 8.5% of [13C]DPA, and 4.2% of [13C]palmitic acid were given to the red sea bream at dose level of 8.0, 16.0, and 47.9 mg/kg by a single oral administration. For [13C]DHA, the maximum plasma concentration (tmax) occurred at 2.00–3.00 h after the oral administration. The peak plasma concentration (Cmax) and the area under the plasma concentration‐time curve to 24 h (AUC0‐24 for [13C]DHA level linearly increased with respect to dosage. [13C]DHA appeared in each organ (plasma, erythrocyte and the fat body of the orbit, liver, intestine, skin, brain, heart and muscle) at 0.5 h and was observed until 24 h. From the values determined for the pharmacokinetic parameters, the range of the effective plasma DHA level for normal growth of the red sea bream was suggested to be between 21.0 and 40.3 μg/mL. For [13C]DPA, the AUC0‐24 and Cmax values also linearly increased with the dosage, but tmax did not depend on it.
A Laboratory Challenge Method for Estimating Taura Syndrome Virus Resistance in Selected Lines of Pacific White Shrimp Litopenaeus vannamei
Authors: White Brenda L. , Schofield Paul J. , Poulos Bonnie T. , Lightner Donald V.
Published: April 2007

Among the strategies being developed to improve survival and harvest yields in the farming of Pacific white shrimp Litopenneus vannumei is breeding domesticated family lines and the selection for further development of those lines that demonstrate resistance to Taura syndrome virus (TSV) challenge in the laboratory. A standardized laboratory challenge method for measuring TSV resistance by per os exposure to the virus, relative to a reference stock of L. vannamei, was developed and used to screen a total of 176 family lines provided by five different companies over a period of several months. All challenged shrimp were exposed to TSV per os by feeding minced TSV‐positive shrimp carcasses at ∼10% of the shrimp biomass once per day for three consecutive days. Studies were carried out for a minimum of 14 d from the first day (day 0) of exposure to TSV. The survival rates obtained following TSV challenge of the selected L. vannamei families ranged from 0% to 100%, with a mean of 31%. The reference line of L. vannamei (“Kona line”) gave survival rates of 0% to 37% with a mean of 13%. The results of the present study demonstrate that the use of a relatively simple laboratory challenge procedure provides a mechanism to evaluate and compare resistance to TSV among selected L. vannamei families and to predict the performance of selected stocks in farm environments where TSV is enzootic.