A Comparative Study of the Dietary Lysine Requirement of Juvenile Striped bass Morone saxatilis and Sunshine bass M. chrysops x M. saxatilis

Previous reports have indicated there are significant differences in both the dietary lysine requirement and the metabolic rate of striped bass and its hybrids. However, there is very little directly comparative data to confirm these suggestions. A series of experiments was conducted to comparatively assess efficiency of protein and energy retention between striped bass Morone saxatilis and sunshine bass M. chrysops♀×M. saxatilis♂ grown under identical culture conditions. In experiment one, a dose response study was conducted using digestible energy (DE) levels of 3,200 kcal/kg and 3,600 kcal/kg. At each level of DE, six levels of dietary lysine were fed to striped bass and sunshine bass. Ten sunshine bass weighing 3.48 ± 0.08 g or six striped bass weighing 3.23 ± 0.14 g were stocked into 15-L tanks supplied with single-pass flow-through fresh water. After 12 wk on the experimental regime, feed conversion ratios (FCR), weight gain, and % nitrogen (N) retention were determined. Nonlinear regression analysis indicated that the dietary lysine requirement of both bass groups was similar. The dietary lysine requirement was determined to be 2.0 ± 0.08% of dry diet (or 6.0 ± 0.26 g lysine/1,000 kcal DE), and 1.7 ± 0.08% of dry diet (or 4.7 ± 0.22 g lysine/1,000 kcal DE), for the 3,200 and 3,600 kcal DE/kg diets, respectively. A second experiment comparatively assessed growth, metabolism, and energy partitioning between striped bass and sunshine bass. Two diets were formulated to be isonitrogenous and isocaloric with a calculated DE level of 3462 kcal/kg and contained lysine concentrations approximating the published dietary requirements of sunshine bass (low lysine = LL diet) and striped bass (high lysine = HL diet). The diets were fed at an average rate of 2% of body weight/d to 25 juvenile striped bass or hybrid bass held separately in eight 2000-L single-pass flow-through tanks supplied with freshwater. In general, growth performance of sunshine bass was superior to striped bass. Both bass groups performed better when fed the HL diet. Mean FCRs were 1.19 ± 0.12 and 1.94 ± 0.29, respectively, for hybrids and striped bass fed the LL diet (P= 0.066); and 1.17 ± 0.07, and 1-58 ± 0.08, respectively, for hybrids and striped bass fed the HL diet (P = 0.011). Mean % gain/d values were significantly higher (P= 0.001) for hybrids (2.77 ± 0.85) than for striped bass (1-30 ± 0.27) when fed the LL diet. When fed the HL diet, mean % gain/d was significantly higher (P = 0.003) for sunshine bass (2.72 ± 0.83) compared to striped bass (1.51 ± 0.25). Additionally, when fed the HL diet, sunshine bass had significantly higher percent nitrogen (P= 0.006) and energy retention (P= 0.014) when compared to striped bass. These results further document that sunshine bass are more efficient at protein and energy retention compared to striped bass in freshwater.     

饲料蛋白质含量对杂交条纹鲈生长的影响

杂交条纹鲈是指条纹鲈 (ＭｏｒｏｎｅＳａｘａｔｉｌｉｓ)和白鲈 (Ｍ .Ｃｈｒｙｓｏｐｓ)的杂交种。 6 0年代中期 ,在美国加州用条纹鲈的卵子和白鲈的精子生产出杂交条纹鲈 (又称棕榈鲈 ) ,另一种相对应的杂交种称为阳光鲈。 80年代末 ,在美国东南部开始养殖杂交条纹鲈并迅速发展成为一项主要的水产养殖产业。杂交条纹鲈适宜养殖水温为 4～ 33℃ ,最适生长水温为 2 5～ 2 7℃。能在各种盐度的水体生长 ,最适溶氧为 6～ 12ｍｇ/Ｌ ,ｐＨ为 7 0～ 7 5。杂交条纹鲈终生为肉食性鱼类 ,在人工饲养条件下亦可摄食配合饲料。该鱼具有显著的杂交生长…     

Significant Augmentation of Sunshine Bass Morone chrysops x M. saxatilis Fillet Highly Unsaturated Fatty Acid Content without Impact on Oxidative Stability or Sensory Attributes

We evaluated production performance, fillet composition, and sensory integrity of sunshine bass (Morone chrysops x M. saxatilis) fed a marine oil-based finishing feed after being raised on a plant oil-based production feed. Two feeds containing either corn oil (CO) or menhaden oil (MO) were fed to sunshine bass according to different feeding regimens at the close of the production cycle: control groups were fed the CO or the MO feeds exclusively; remaining groups were transitioned from the CO feed to the MO feed at 4-, 8- or 12-week intervals. Replacing MO with CO yielded fillets with distinctly different fatty acid profiles; however, finishing with an MO-based feed for 4–8 weeks offered significant compensation for reductions in fillet nutritional quality. Production performance and fillet sensory characteristics were largely unaffected by dietary lipid source, suggesting fillet fatty acid profile can be manipulated to maximize nutritional value of cultured fillets without reducing consumer acceptance.     

Early growth and survival of striped bass, Morone saxatilis (Walbaum), and its phenotypically similar hybrid (M. saxatilis × M. chrysops) using an otolith marking method

An experiment using differently marked larval striped bass, Morone saxatilis (Walbaum). and its hybrid (M. saxatilis x M. chrysops (Rafinesque)) was performed in two grow-out ponds. Larval striped bass were immersed in oxytetracycline solution to mark their otoliths; hybrids received no treatment. Larvae from both groups were mixed and stocked at 8 days post hatch into the ponds. Striped bass and hybrid larvae grew to a significantly larger size at 35 days in one pond. In both ponds, hybrid lengths at 35 days after hatch were significantly greater than striped bass lengths. However, the magnitude of the size difference between hybrids and striped bass was twofold greater (10%) in one pond than in the other (5%). The proportion of striped bass juveniles at 35 days differed from the initial stocking proportion (0.53) only in one pond, where hybrids showed 12% greater survival than striped bass. Results suggested that the relative survival of hybrids was influenced by growth conditions in the ponds. Based on the ease of protocol and analysis of the marking experiment, we recommend its use to (1) investigate relative performance between genetic groups of young fish in common environments; and (2) predict the effects of introductions of genetically altered fishes.     

Lysine supplementation of commercial fishmeal‐free diet in hybrid striped bass Morone chrysops x M. saxatilis affects expression of growth‐related genes

Our recent results in hybrid striped bass (HSB) concluded that ideal protein theory accurately predicts first‐limiting amino acids in commercial diet formulations if accurate amino acid availability data are used and that appropriate levels of supplemental lysine are needed to improve fish performance from fishmeal‐free diets. Our goal in this study was to elucidate how dietary lysine supplementation of a commercial fishmeal‐free diet influences the expression of two genes, myostatin and myogenin, controlling myogenesis in differentially growing groups of HSB. Real‐time RT‐PCR results in HSB suggest that the levels of lysine added to the diet (17.8, 35.1, 51.0 g kg^?1 of diet) has an impact on myogenin relative to the basal unsupplemented diet, but no effect on myostatin. Moreover, our data further suggest that the amount of dietary lysine supplementation influenced the ratio of myostatin/myogenin expression in HSB and that this pattern mimicked that of most of the growth, composition of growth and nutrient retention data from our previous study and may therefore be a useful marker for selecting fish for improved growth performance.     

Dietary vitamin E requirement of hybrid striped bass (Morone chrysops female × M. saxatilis male)

This study was conducted to determine the dietary vitamin E requirement of juvenile hybrid striped bass ( Morone chrysops female ×  Morone saxatilis male). Semi-purified diets supplemented with 0.2 mg Se kg⁻¹ from Na₂SeO₃ and either 0 (basal), 10, 20, 40, 60, or 80 mg vitamin E kg⁻¹ as  DL -α-tocopheryl acetate were fed to hybrid striped bass initially averaging 1.8 ± 0.1 g (mean ± SD) for 12 weeks. Fish fed the basal diet, which contained 5.8 mg α-tocopherol kg⁻¹ dry weight, were darker in colour and had reduced weight gain, as well as generally reduced haematocrit values compared with fish fed diets supplemented with vitamin E. In addition, fish fed diets containing less than 20 mg supplemental vitamin E kg⁻¹ had significantly ( P  < 0.05) reduced weight gain and feed efficiency compared with those fed diets supplemented with vitamin E at 20–80 mg kg⁻¹. Dietary supplementation of vitamin E caused incremental increases in the concentration of α-tocopherol in both plasma and liver tissues. However, hybrid striped bass fed graded levels of vitamin E did not exhibit a dose response in terms of ascorbic acid-stimulated lipid peroxidation of hepatic microsomes. Regression analysis of weight gain data using the broken-line model indicated a minimum vitamin E requirement ( ±  SE) of 28 ( ±  3) mg kg⁻¹ dry diet. Based on these data, the dietary vitamin E requirement of hybrid striped bass appears to be similar to that determined for other fish species.     

Effects of Amylopectin/Amylose Starch Ratio on Growth, Body Composition and Glycemic Response of Sunshine Bass Morone chrysops × M. saxatilis

Manipulation of the ratio of amylopectin (α‐[1,4] and α‐[1,6] linked glucose) to amylose (α‐[1,41 linked glucose) starches in the carbohydrate fraction of the diet has been used to improve carbohydrate and lipid metabolism in mammalian models. A 10‐wk feeding trial was conducted to determine the effect of dietary amylopectin/amylose ratio on growth and composition of growth of advanced sunshine bass (Morone chrysops × M. saxatilis) fingerlings (60 g, initial weight). Fish were fed cold‐pelleted, semipurified, isonitrogenous (35% crude protein), isocaloric (3.6 kcaVg protein), isolipidic (5%) diets containing 25% carbohydrate. The carbohydrate fraction of the diets was composed of either glucose, dextrin, 100% amylopectin/0% amylose, 70% amylopectin/30% amylose, or 30% amylopectin/70% amylose. Diets differing in ratios of amylopectin/amylose were achieved by adjusting the proportion of high‐amylopectin (100% amylopectin) to high‐amylose (70% amylose) corn starch. Diets were fed to fish in quadruplicate 76‐L tanks (seven fish/tank) connected to a brackish water (5‐7%v) recirculating culture system with biofiltration. Weight gain ranged from 195 to 236% of initial weight (60 g) and was significantly greater (P < 0.1) for fish fed diets containing 25% carbohydrate as dextrin or as 70% amylose and significantly lower in fish fed diets in which carbohydrate was composed of 30% amylose, 100% amylopectin, or glucose. Feed efficiency ranged from 0.52 to 0.61 and was higher in fish fed the diet containing the highest concentration of amylose and lower in fish fed the diet containing glucose. Hepatosomatic index was highest (2.71) in fish fed the diet containing glucose and lowest (1.401.45) in fish fed diets containing high‐amylose cornstarch. Intraperitoneal fat ratio was distinctly lower in fish fed diets containing some amylose as compared to those fed diets without amylose. Liver lipid was significantly lower (4.8%) in fish fed the diet containing glucose and almost twice as high (7.3‐8.9%) in fish fed the diets containing any starch. Glycogen content of the liver decreased from approximately 12% in fish fed the diet containing glucose to 5% in fish fed the diets containing amylose. Muscle proximate composition and ratio were unaffected by the dietary treatments. Fasting levels (15 h) of blood glucose in fish reared for 10 wk on the diet containing glucose were significantly elevated (5.5 mmol/L) when compared to fasting levels of those that had been reared on diets containing starch (3.4‐1.1 mmol/L). Fish fed the diet containing glucose exhibited maximum blood concentrations (14.6 mmoVL) 4 h postprandial then rapidly declined to nearly fasting levels within 8 h postprandial. In contrast, maximum plasma glucose concentrations in fish fed diets containing starch were roughly half (6.8‐8.1 mmol/L) those of fish fed the diet containing glucose. Blood glucose in fish fed diets containing dextrin or predominantly amylopectin starch remained elevated longer than that of fish fed diets containing glucose or predominantly amylose starch. Glycemic response appeared to decrease with increasing dietary amylose content. These data suggest that feeding diets in which a greater portion of the starch is amylose may be a useful strategy for improving carbohydrate use in sunshine bass.     

Tank culture of larval sunshine bass, Morone chrysops (Rafinesque)×M. saxatilis (Walbaum), at three feeding levels

Sunshine bass, a hybrid of female white bass Morone chrysops (Rafinesque) and male striped bass M. saxatilis (Walbaum), fingerling production occurs almost exclusively in ponds. To increase production and maintain year‐round production in temperate climates, indoor tank culture is required. While tank production of fingerlings has been demonstrated, little is known about feeding requirements. Sunshine bass larvae, stocked at 75 L^?1 in 100 L of brackish water, were fed sequentially with rotifers Brachionus plicatilis cultured with a Nannochloropis algae paste and enriched with highly unsaturated fatty acids, decapsulated Artemia nauplii, and a microencapsulated commercial diet. The larvae in one treatment (three replicates) were initially fed rotifers at a daily rate of 20 mL^?1, then nauplii at an initial rate of 2 mL^?1, and then the commercial diet at 1 g. Larvae in two other treatments received two and three times as much food daily. The highest feeding rate resulted in a survival (52.9%) that was significantly higher than the survival rate (22.4%) of larvae fed the least. The total biomass produced was the highest in the treatment receiving the most food. The lowest feeding rate produced the least fish, but they were the heaviest. The intermediate feeding rate produced the shortest fish (11.3 mm).     

Selective breeding for the hybrid striped bass (Morone chrysops, Rafinesque ×M. saxatilis, Walbaum) industry: status and perspectives

The hybrid striped bass (HSB) farming industry has considerable potential for growth into domestic retail markets, but expansion of this industry is limited by high production costs that dictate high prices for HSB. It is widely recognized within the industry that selective breeding of an improved HSB will be required to increase production efficiency and reduce market prices. A National Program of Genetic Improvement and Selective Breeding for the HSB Industry has been initiated and some progress has been made toward domestication of the parent species of the hybrid. However, uncertainty remains as to which breeding procedures will most rapidly yield sustainable genetic gains in key production traits. This paper consolidates and reviews general information on the biology of temperate basses (genus Morone) relevant to selective breeding of improved HSB. The topics covered include control of reproduction, geographic distribution of stocks and population genetic variation. This is followed by a brief review of the current application of selective breeding techniques, including those based on molecular markers. Finally, we discuss potential avenues for genetic improvement of HSB in a selective breeding program.     

Effect of Stocking Rate on Growing Juvenile Sunshine Bass,Morone chrysops × M. saxatilis,in an Outdoor Biofloc Production System

The biofloc technology production system is a production‐intensifying management strategy used primarily for culturing tilapia and penaeid shrimp, both of which can consume the biofloc. Other fish can be grown in biofloc systems because the biofloc serves to maintain water quality, metabolizing the ammonia excreted by intensively fed fish. A dose–response study was conducted in an outdoor biofloc system to begin quantifying the stocking rate production function for sunshine bass, Morone chrysops × Morone saxatilis, advanced fingerlings. Sunshine bass (2.9 ± 0.2 g/fish) were stocked into tanks at 50–250 fish/m² in 50 fish/m² increments. After 94 d, gross yields ranged from 1.4 to 3.1 kg/m³ and were independent of stocking rate. Harvested fish were separated into two size groups: smaller than 115 mm total length (TL, target fish) and larger than 115 mm TL (jumper fish). Target fish increased linearly from 62 to 93% and jumpers decreased linearly from 38 to 7% of the population, respectively, as stocking rate increased. The outdoor biofloc system offers potential for intensifying the production of advanced sunshine bass fingerlings, but feed consumption appeared to be impeded by high total suspended solids concentrations. Further research is needed to optimize stocking rates and solids management.     

Effects of Cottonseed and Alfalfa Meals as Fertilizers on Production of Palmetto Bass (Morone saxatilis × M. chrysops) Fingerlings in Plastic-Lined Ponds

Effects of cottonseed meal versus alfalfa meal fertilization on water quality, zooplankton density, and production of phase I palmetto bass, Morone saxatilis × M. chrysops, were compared in plastic-lined ponds. Cottonseed meal promoted better (P < 0.05) water quality, timing of high zooplankton density development, and growth and yield of palmetto bass. Cost of cottonseed meal toward fish production was $0.75/kg of fish, while that of alfalfa meal was $1.74/kg of fish.     

Confinement and Transport-Induced Stress in White Bass Morone chrysops × Striped Bass M. saxatilis Hybrids: Effect of Calcium and Salinity1

Stress induced by severe confinement in cages and by simulated transport was evaluated in reciprocal white bass × striped bass hybrids (Morone chrysops × M. saratilis) after acclimation to various calcium concentrations in freshwater (5, 10, 20, 40, and 80 mg/L calcium) and various salinities (1, 8, 16, and 24%o) at 25 C. Survival was monitored in both confinement and transport events. In confinement events, changes in plasma osmolality were used as an indicator of osmoreg-ulatory dysfunction. After 6 h of severe confinement in cages, survival was significantly affected by treatments in both freshwater (FW) and saltwater (SW) events. Survival was greatest in 80 mg/L calcium in FW treatments and 8%o in the SW treatments. Simultaneous analysis of both FW and SW confinement data revealed that, after compensating for fish weight, survival increased as environmental ionic content increased (up to 8%o) then decreased with increasing salinity. Plasma osmolality decreased significantly from baseline levels with respect to confinement time in all FW treatments. Significant differences in plasma osmolality were observed among SW treatments: plasma osmolality of fish confined in 1%o decreased while those confined in salinities of 16 and 24%o increased. The plasma osmolality offish confined in 8%o remained near baseline levels. Almost no mortality (<5% in all treatments) occurred during (12 h) and after (5 d) transport in both FW and SW. Fish were in good condition and acclimated to transport water quality prior to transport events which may have been a major reason for high survival. Results from this study indicate that detrimental effects due to handling and transporting hybrid striped bass are reduced in FW environments that provide sufficient calcium and in SW environments which are near isoosmotic with the plasma.     

Ration of 20:3 (n-9) to 20:5 (n-3) in Phospholipids as an Indicators of Dietary Essential Fatty Acid Sufficiency in Striped Bass,Morone saxarilis,and Palmetto Bass,M. saxatilis x M. chrysops

The effects of feeding different sources of brine shrimp nauplii with different fatty acid compositions on growth, survival, and fatty acid composition of striped bass, Morone saxarilis and palmetto bass (M. saxatilis x M. chrysops) were determined. The sources of brine shrimp were Chinese (CH), with a high percentage of 20:5(n-3), eicosapentaenoic acid (EPA), and Colombian (COL), San Francisco Bay (SFB), and Great Salt Lake (GSL), with low percentages of EPA but high percentages of 18:3(n-3), linoienic acid. None of the brine shrimp sources contained a measurable amount of 22:6(n-3), docosahexaenoic acid (DHA). After enrichment with menhaden oil to increase the content of EPA and DHA, the GSL brine shrimp nauplii were also fed to hybrid striped bass.Growth and survival of fish larvae fed brine shrimp nauplii with high percentages of EPA and DHA (CH and GSLE) were higher (P < 0.05) than those of fish fed brine shrimp with a low percentage of EPA (COL, SFB, and GSL). The ratio of 20:3(n-9) eicosatrienoic acid (ETA), to DHA in polar lipids (phospholipids) of fish, traditionally used as an indicator of essential fatty acid (EFA) sufficiency of the diet, was not a reliable indicator of essential fatty acid sufficiency of diets for larval striped bass and hybrid striped bass. However, the ratio of ETA to EPA appears to be an appropriate indicator. An ETA-to-EPA ratio in phospholipids of less than 0.10 is consistent with an EFA sufficient diet.     

Intestinal phytase I: Detection and preliminary characterization of activity in the intestinal brush border membrane of hybrid striped bass Morone saxatilis × M. chrysops

While numerous studies have evaluated intestinal phytase activity in terrestrial monogastric species, little work has been conducted investigating the enzyme's activity in finfish. This experiment was conducted to determine if hybrid striped bass Morone saxatilis × M. chrysops possess intestinal phytase activity, and to perform a preliminary characterization of this activity in terms of pH, metal ion dependence and substrate kinetics. Hybrid bass do exhibit low levels of intestinal phytase activity. The activity has an acidic pH optimum between 3.5 and 4.5. Low concentrations of Mn²⁺ slightly enhance this activity. The divalent cations Mg²⁺ and Zn²⁺ were shown to either have no effect on the enzyme activity or to be inhibitory, particularly at high concentrations. The present results indicate that intestinal phytase activity in hybrid bass does follow Michaelis-Menten kinetics, with estimated K_m and V_max values of 2.5 mM phytate and 4.8 units mg⁻¹ protein, respectively. The physiologic significance of the enzyme's presence in hybrid striped bass is questionable due to the low activity as compared to terrestrial monogastrics, the acidic pH optimum and the low affinity the enzyme appears to have for phytate. These observations also raise the question of whether the intestinal phytase activity detected in hybrid bass is merely a manifestation of non-specific acid phosphatase activity. Further investigation is needed to determine the practical significance of phytase activity in hybrid bass in terms of phytate phosphorus utilization. Additional experiments should also be conducted which evaluate intestinal phytase activity in other important aquacultured finfish species. This revised version was published online in July 2006 with corrections to the Cover Date.     

High Drift Rate Effects of Propanil and Basis Gold on the Plankton Communities and Water Quality of a Prestocking Sunshine Bass,Morone chrysops × M. saxatilis,Fry Pond

ABSTRACT

Mesocosm-testing of aerially applied herbicides propanil and Basis Gold (86.8% atrazine) and indicated high drift rates (10–20% of field rates) resulted in adverse impacts on aquaculture production-pond phytoplankton, zooplankton, and critical water-quality variables. Effects on fry pond phytoplankton, zooplankton, and water quality from these herbicides were evaluated at 30% of field application rates, equal to the worst-case scenario from drift to these smaller ponds with consequent higher concentrations. The study was conducted in 12 outdoor pool mesocosms of 500 L volume, filled with pond water from an adjacent 0.1 ha pond fertilized and prepared as recommended for sunshine bass, Morone chrysops × M. saxatilis, fry stocking. Plankton and water quality samples were taken just prior to herbicide application (day 0) and on days 1,2,3,4-zooplankton only, and on day 7 after application. Field application rates for Basis Gold and propanil were 0.8 kg active ingredient and 1.80 kg/ha, respectively. Significant changes from control treatment values were found for several parameters in both herbicide treatments. Following application on June 20, net primary productivity was significantly depressed on day 1 in the propanil treatments, but increased on days 2 and 3. Morning dissolved oxygen (DO) was lower on days 1–3, but not to critical levels. Also, in the presence of propanil, pH and consequently UIA were lower from day 1 to 3. Basis Gold reduced morning DO on days 2 and 3, but not net primary productivity. Nitrite-N, however, was significantly higher on day 1. Phytoplankton total numbers, and the cyanobacterium Chroococcus sp. which dominated, were reduced by propanil on days 1 -3; and similarly affected by Basis Gold on days 2 and 3. Numbers of green algae, Scenedesmus sp. and Coelastrum sp., and diatoms were, however, stimulated by propanil and diatoms by Basis Gold. Zooplankton were little affected by either herbicide. Thus, high levels of drift from propanil and Basis Gold should not result in negative impacts on fry production.