Sunshine Bass Research Articles

A comparison of two faecal collection methods for protein and amino acid digestibility coefficients of menhaden fish meal and two grades of poultry by-product meals for market-size sunshine bass (Morone chrysops × M. saxatilis)

Apparent digestibility and availability coefficients for protein and amino acids in menhaden fish meal (MEN), pet-food grade (PBM-pet,) and feed-grade poultry by-product meal (PBM-feed) were determined for market-size (500 g) sunshine bass in two consecutive trials using passive netting (1.6 mm mesh) followed by manual stripping of faeces. A reference diet resembling a commercial feed was formulated to meet or exceed all known nutritional requirements of hybrid striped bass. Test diets were formulated to contain a 70 : 30 mixture of reference diet to test ingredient with chromic oxide (1%) serving as the inert marker. Diets were extruded under commercial conditions and the reference diet was fed for two weeks in order to acclimate fish to experimental conditions. Each diet was randomly assigned to triplicate tanks containing 30 fish each. Fish were fed their respective diet twice daily to apparent satiation for two weeks, with faecal collections being conducted on the 7th and 14th day, in each trial. ADC values determined in the net method were highly variable and generally lower than ADCs obtained by stripping. Consistently lower and highly variable chromium concentrations were found in the net method faecal samples and suggest that marker loss relative to nutrient content, or dilution of marker with non-faecal matter, on the net collectors influenced results in that trial. In contrast, the standard errors of ADCs determined in the strip method were less than 5 percentage points in most cases. Protein digestibility ranged from a low of 51% (PBM-feed) to a high of 87% (PBM-pet) in the net method, and from a low of 80% (PBM-feed) to a high of 99% (MEN) in the strip method. With the exception of Lys, no differences in amino acid availabilities among diets were found in the net method. In the strip method, protein digestibility and amino acid availabilities in MEN were generally greater than those found in PBM-pet or PBM-feed, whereas ADCs were not significantly different between the two poultry by-products. Based on the conditions of the present study, net collection of faecal matter can not be recommended for determining the digestibility of nutrients in feed ingredients for market-size sunshine bass. Digestibility coefficients obtained by the strip method for feed and petfood grades poultry by-product were higher than those previously reported and will be facilitate more efficient and economical diet formulations for larger sunshine bass.

Candidate Species for Florida Aquaculture: Hybrid Striped Bass, Morone saxatilis x Morone chrysops

FA155, a 9-page illustrated fact sheet by Cortney L. Ohs, Christian L. Miller, and R. LeRoy Creswell, describes these crosses between striped bass and white bass, commonly called sunshine bass and palmetto bass — geographical distribution and habitat, phases of production, pond, cage, and tank production, feeding, water quality, and marketing. Includes references. Published by the UF School of Forest Resources and Conservation Program for Fisheries and Aquatic Sciences, December 2008. FA155/FA155: Candidate Species for Florida Aquaculture: Hybrid Striped Bass, Morone saxatilis x Morone chrysops (ufl.edu)

Comparison of zootechnical performances, welfare condition and quality traits of hybrid striped bass (Morone chrysops x Morone saxatilis) reared in different Italian farms

Growth performances of sunshine bass (initial m.b.w.=200±50 g) were examined in 3 different rearing conditions: concrete square basins (HSB-1); raceways (HSB-2); natural ponds (HSB-3). Fish received the same extruded feed (prot. 48.8%; lip. 17.8%). The trial lasted 16 months in HSB-1 and HSB-2 and only 12 months in HSB-3 due to unfavourable welfare status and low growth performances. At harvest (after 16 months), sunshine bass reached a satisfactory mean weight without significant differences between groups. HSB-2 fish were longer with a smaller circumference, probably due to different hydrodynamics of the raceway. Glucose, cholesterol, triglycerides, protein, lactic dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), glycogen of plasma or tissue were not affected by rearing conditions as well as the proximate composition and the fatty acid profile of the fillet.

Comparison of Tank Treatments with Copper Sulfate and Potassium Permanganate for Sunshine Bass with Ichthyobodosis

The biflagellated, single-celled parasite Ichthyobodo necator can cause significant losses among fish populations, particularly those cultured in tanks. Treatments of KMnO4 and CuSO4 were evaluated against a naturally occurring I. necator infestation on sunshine bass (female white bass Morone chrysops x male striped bass M. saxatilis) raised in tanks. Four-hour static treatments with 3 mg of KMnO4/L of water (2.5 mg/L above the determined KMnO4 demand) or 2 mg of CuSO4/L of water (total alkalinity = 207 mg/L; total hardness = 95 mg/L) were randomly applied to 4 tanks/treatment (23 fish/tank); the same treatments were reapplied 2 d later. Four tanks were used as positive controls. By 2 d posttreatment (after the second treatment), only 17.4% of the untreated control fish survived, and a sample of the remaining fish was heavily infested with I. necator. All remaining control fish were dead by 5 d posttreatment. The KMnO4 treatment significantly curtailed the initial mortality (survival = 92.4%) and slightly reduced the high parasite loads at 2 d posttreatment. However, fish mortalities increased dramatically over the next 3 d (survival at 5 d posttreatment = 37.5%), and parasite loads from sampled fish remained high. The CuSO4 treatment was effective in significantly lowering the parasite load (almost eliminating I. necator) and maintaining a high fish survival (87.5%) by 5 d posttreatment. The findings in this study clearly demonstrate that CuSO4 is a viable treatment for ichthyobodosis in tanks.

Fishmeal-based diet decreases the redness of sunshine bass (Morone chrysops×Morone saxatilis) fillets

Abstract The objectives of the present study were to determine the effects of feeding a fishmeal-based diet on color attributes and lipid oxidation in sunshine bass ( Morone chrysops × Morone saxatilis ) fillets during retail display. A balanced diet containing 30 percent fishmeal (FM) or a diet containing poultry byproduct meal as a complete replacement of fishmeal (PB) was fed to sunshine bass for fifteen months. Harvested fish were filleted, overwrapped with polyvinyl chloride film and stored at 2 °C (REF) or over ice (ICE), under an illuminated retail display. Samples ( n = 6) were analyzed after 0, 3, 6, or 9 d storage for color attributes (CIE L ∗ , a ∗ , b ∗ , hue angle and chroma), thiobarbituric acid-reactive substances (TBARS), and pH. TBARS and pH increased ( P P a ∗ (redness) value and greater ( P

Minimizing Fish Oil and Fish Meal with Plant‐based Alternatives in Sunshine Bass Diets without Negatively Impacting Growth and Muscle Fatty Acid Profile

Abstract We determined whether canola oil could spare menhaden oil (MO) in diets containing minimal fish meal without affecting sunshine bass, Morone chrysops × Morone saxatilis, production. Seven isonitrogenous, isocaloric (41.7% crude protein and 14.6% crude lipid) diets containing graded levels (0, 20, 40, 60, 80, or 100%) of menhaden to canola oils with 20% menhaden meal (MM) or 100% canola oil with 20% lipid‐extracted MM were fed to sunshine bass (initial weight 9.3 ± 0.16 g; mean ± SD) twice daily to apparent satiation for 10 wk. Sunshine bass fed less than 40% of their dietary lipid as MO exhibited significantly (P < 0.05) lower feed intake and growth rates. Increased concentrations of saturated, n‐3, and n‐3 highly unsaturated fatty acids (FA) in the fillet were associated with MO‐rich diets, while monounsaturated and n‐6 FA were most common in fillets from fish fed diets rich in canola oil. Reducing MO to 40% of the dietary lipid in diets containing minimal fish meal allows for efficient utilization of marine resources without negatively impacting juvenile sunshine bass production.

Replacement of Fish Meal with Poultry By‐product Meal as a Protein Source in Pond‐raised Sunshine Bass, Morone chrysops ♀ × M. saxatlis ♂, Diets

Abstract Replacement of fish meal (FM) as a protein source with alternative sources of protein in aquaculture diets has been widely explored in aquaculture. The goal of replacement of FM in production diets is to maintain growth, lower production costs, and increase sustainability. Evaluation of the replacement of FM with poultry by‐product meal (PBM) in phase II sunshine bass diets, Morone chrysops × M. saxatilis, was conducted in ponds over 246 d. Four diets were formulated to be isonitrogenous (37%) and isocaloric (4 kcal/g) with different levels of FM replacement with PBM (0, 33, 67, and 100%, Diets 1–4, respectively). Twelve ponds were stocked with 400 phase II sunshine bass (mean weight 5.6 g) and randomly assigned one of the four diets. Fish were fed below satiation based on predicted growth and feed conversion, initially once daily (1700 h) and then twice daily (0700 and 1700 h) as water temperatures and feeding activity increased. Diets were evaluated based on production and performance indicators, body composition, and economic analysis. Production results revealed no significant differences in mean final individual fish weight (511 ± 21 g), net production (4257 ± 247 kg/ha), and survival (85 ± 2%). No significant differences occurred between the performance indicators: mean feed conversion ratio (2.47 ± 0.11), specific growth rate (1.84 ± 0.02), and protein conversion efficiency (23 ± 1.3%). Body composition was statistically similar for mean percent fillet weight (49 ± 0.6%) and percent intraperitoneal fat (9.8 ± 1.0%); however, the hepatosomatic index was significantly different between Diets 3 (3.7 ± 0.1%) and 4 (3.2 ± 0.1%). Mean proximate analysis of whole fish (dry weight basis) was not significantly different among treatments yielding the following: percent protein (46 ± 0.4%), lipid (47 ± 1.3%), and ash (8 ± 0.7%). Mean fillet composition (dry weight basis) also revealed no significant differences: percent protein (72 ± 0.8%), percent lipid (30 ± 1.6%), and percent ash (5 ± 0.2%). Proximate analysis was also performed on the diets and revealed a significantly lower protein content in Diet 3 (34.3 ± 0.5%) compared to the other diets (37.1 ± 0.4%). Amino acid analysis of the diets indicated a possible deficiency in methionine in Diets 3 and 4. Based on production, performance, and body composition, the results indicate that complete replacement of FM with PBM in sunshine bass diets is feasible; however, economic analysis suggests that the replacement of FM with PBM may result in reduced revenue over feed costs.

Influence of Vitamin E Source and Dietary Supplementation Level on Production Performance of Sunshine Bass, Morone chrysops ♀ × Morone saxatilis ♂, Fillet Tocopherol Content, and Immunocompetency during Stress and Bacterial Challenge

Abstract We evaluated the effects of dietary vitamin E concentration and source on production performance and immunocompetency of sunshine bass, Morone chrysops × Morone saxatilis, following stress and disease challenge. Four diets were formulated to contain requisite levels (1×) or five times (5×) the vitamin E requirement of sunshine bass as met by synthetic vitamin E (SYNE) or natural source vitamin E (NSVE). Each diet was fed to juvenile sunshine bass for 8 wk prior to experimental challenges. Replicate tanks within each dietary treatment were challenged with stressor exposure (chasing with dip net), incidental Flavobacterium columnare exposure, or both; control groups were not challenged. Pathogen and/or stressor exposure largely resulted in significant reductions in immunological performance. Although significant independent dietary effects were not observed among immunological parameters, suppression of complement and macrophage respiratory burst activities was numerically lower within the 5× NSVE treatment. Production performance was largely unaffected by dietary vitamin E source or level. Fillet α‐tocopherol concentration was significantly higher among fish fed the 5× diets (40.7/41.6 vs. 12.2/14.5 μg/g dry tissue for 1× diets); however, the dietary concentration required to achieve these levels was lower for NSVE. Although super‐requirement levels of either source of vitamin E were apparently beneficial, NSVE was effective at ∼50% lower supplementation levels.

Fatty Acid Profile of Sunshine Bass: I. Profile Change is Affected by Initial Composition and Differs Among Tissues

Fatty acid (FA) composition of fillet tissue can be tailored by transitioning fish from alternative lipid-based, low long-chain polyunsaturated fatty acid (LC-PUFA) grow-out feeds to high LC-PUFA "finishing" feeds. To address whether grow-out feed composition influences the responsiveness of fillet tissue to finishing, sunshine bass (SB, Morone chrysops x M. saxatilis) were reared to a submarketable size on grow-out feeds containing fish oil (FO) or a 50:50 blend of FO and coconut (CO), grapeseed (GO), linseed (LO), or poultry (PO) oil. For the final 8 weeks of the trial, fish were either maintained on assigned grow-out feeds or finished with the 100% FO feed. Production performance was unaffected by dietary lipid source, but fillet FA profile generally conformed to nutritional history. Regardless of grow-out regimen, finishing had a significant restorative effect on fillet FA composition; however, complete restoration of control levels of 20:5n-3, 22:6n-3, total LC-PUFA and n-3:n-6 FA ratio was achieved only among fish fed the CO-based grow-out feed. Saturated fatty acids (SFA) appear to be preferential catabolic substrates, whereas medium-chain and long-chain PUFA are selectively deposited in tissues. Provision of SFA in grow-out feeds appears to optimize selective FA metabolism and restoration of beneficial fillet FA profile during finishing.

Fatty Acid Profile of Sunshine Bass: II. Profile Change Differs Among Fillet Lipid Classes

Fatty acid (FA) profile of fish tissue mirrors dietary FA profile and changes in a time-dependent manner following a change in dietary FA composition. To determine whether FA profile change varies among lipid classes, we evaluated the FA composition of fillet cholesteryl esters (CE), phospholipids (PL), and triacylglycerols (TAG) of sunshine bass (SB, Morone chrysops x M. saxatilis) raised on feeds containing fish oil or 50:50 blend of fish oil and coconut, grapeseed, linseed, or poultry oil, with or without implementation of a finishing period (100% FO feed) prior to harvest. Each lipid class was associated with a generalized FA signature, irrespective of nutritional history: fillet PL was comprised largely of saturated FA (SFA), long-chain polyunsaturated FA (LC-PUFA), and total n-3 FA; fillet TAG was higher in MC-PUFA and total n-6 FA; and fillet CE was highest in monounsaturated FA (MUFA). Neutral lipids reflected dietary composition in a near-direct fashion; conversely, PL showed evidence of selectivity for MC- and LC-PUFA. Shorter-chain SFA were not strongly reflected within any lipid fraction, even when dietary availability was high, suggesting catabolism of these FA. FA metabolism in SB is apparently characterized by a division between saturated and unsaturated FA, whereby LC-PUFA are preferentially incorporated into tissues and SFA are preferentially oxidized for energy production. We demonstrated provision of SFA in grow-out feeds for SB, instead MC-PUFA which compete for tissue deposition, meets energy demands and allows for maximum inclusion of LC-PUFA within fillet lipids.

Digestibility of Dry Matter, Protein, Lipid, and Organic Matter of Two Fish Meals, Two Poultry By‐product Meals, Soybean Meal, and Distiller’s Dried Grains with Solubles in Practical Diets for Sunshine Bass, Morone chrysops ×M. saxatilis

Abstract Limited information is available on digestibility of nutrients in various practical ingredients used in diets for commercially important finfish species, such as hybrid striped bass. This information is especially needed for sunshine bass, Morone chrysops ×M. saxatilis, to improve least‐cost diet formulations and to allow effective substitution of feedstuffs. A study was conducted with large (867 g) sunshine bass to determine the apparent digestibility coefficients (ADCs) for moisture, protein, lipid, and organic matter (OM) in a variety of ingredients in floating, extrusion‐processed, diets. The practical ingredients tested were menhaden (MEN) fish meal (FM), anchovy (ANCH) FM, pet‐food grade poultry by‐product meal, feed‐grade poultry by‐product meal, dehulled soybean meal (SBM), and distiller’s dried grains with solubles (DDGS). Test diets consisted of a 70:30 mixture of reference diet to test ingredient with chromic oxide (1.0%) as the inert marker. Reference and test diet ingredients were mixed and extruded on a Wenger X85 single‐screw extruder to produce floating pellets. The digestibility trials were conducted in twelve 1200‐L circular tanks. Diets were randomly assigned to tanks of 30 sunshine bass and were fed once daily to satiation. Protein digestibility coefficients were significantly (P < 0.05) different among test ingredients and ranged from 86.42% for MEN to 64.94% for DDGS. Lipid ADCs were significantly different (P < 0.05) among test ingredients and ranged from 92.14% for MEN to 57.11% for SBM. OM ADCs were significantly different (P < 0.05) among test ingredients and ranged from 89.41% for MEN to 16.94% for DDGS. This information will assist in the formulation of more efficient, economical diets for sunshine bass.

Influence of Stress, Exertion, and Dietary Natural Source Vitamin E on Prostaglandin Synthesis, Hematology, and Tissue Fatty Acid Composition of Sunshine Bass

AbstractWe evaluated the effect of dietary natural source vitamin E (NSVE) on hematology and tissue composition of sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis) at rest and under the physical stress of exertion. Experimental diets were formulated to contain 1, 2, 5, or 30 times the dietary vitamin E requirement of sunshine bass as met by NSVE (22 mg NSVE/kg of feed, supplemental). After an 8‐week feeding trial, dietary treatment groups were subdivided for experimental exertion (forced swimming at 0.12 m/s): Control (no exercise), short‐term exertion (30 min), and long‐term exertion (180 min). Short‐term exertion induced the greatest plasma cortisol concentrations and depressed hematocrit. Dietary NSVE and exertion treatments were observed to affect eicosanoid synthesis via significant effects on cytosolic phospholipase (cPLA2) activity in adipose tissue but not white muscle or hepatic tissue. At rest, increasing NSVE was associated with increased adipose cPLA2 activity, suggesting elevated liberation of arachidonic acid (20:4[n‐6], where 20 is the number of carbon atoms, 4 is the number of double bonds, and 6 is the position of the first double bond from the methyl end) from this storage site; the ratio of 20:4(n‐6) to eicosapentaenoic acid (20:5[n‐3]) was accordingly reduced in adipose tissue. Resultant cardiac prostaglandin F2α (PGF2α) was also affected by dietary and exertion treatments; however, these results were not wholly congruent with alterations in cPLA2 activity. Levels of PGF2α decreased in association with the stress response but only among super‐requirement NSVE groups. Across all dietary treatments, exertion resulted in increased glucose liberation and minor reductions in hepatic glycogen stores. Exertion was not observed to affect tissue fatty acid composition, whereas increasing dietary NSVE was associated with minor changes in tissue composition. We conclude that dietary NSVE has some regulatory influence over eicosanoid synthesis but the mechanism is apparently not restricted to cPLA2‐mediated 20:4(n‐6) release. Moreover, NSVE may affect response to stressor exposure or exertion; however, further research is needed to fully elucidate the physiological consequences of super‐requirement NSVE supplementation.

Effect of Rotifer Enrichment on Sunshine Bass Morone chrysops × M. saxatilis Larvae Growth and Survival and Fatty Acid Composition

Abstract The effect of enriching rotifer prey with highly unsaturated fatty acids on sunshine bass Morone chrysops × M. saxatilis larval survival and growth from ages 4 to 12 d posthatch was determined. Comparisons were made among larvae fed (1) rotifers cultured with Nannochloropsis paste versus rotifers cultured with Nannochloropsis paste and enriched with Culture Selco 3000; (2) no rotifers versus rotifers cultured with Nannochloropsis paste and enriched with Culture Selco 3000; and (3) rotifers cultured with Nannochloropsis paste and enriched with Culture Selco 3000, rotifers cultured with Nannochloropsis and Pavlova pastes and enriched with Culture Selco 3000, and rotifers cultured with Nannochloropsis paste and enriched with Culture Selco 3000 and Super Selco. The only differences in survival were unfed larvae with practically no survival compared to 55.4% survival for larvae fed rotifers cultured with paste plus Culture Selco 3000. Larvae fed rotifers cultured with paste plus Culture Selco 3000 were longer and had greater condition than those fed rotifers cultured with paste. Additional enrichment with Pavlova sp. or Super Selco had no affect. A canonical analysis of fatty acid contents of diets, rotifers, and fry supported evidence from harvest results. Distances between centroids indicated distinct differences among diets, less distinction among the rotifers, and little difference among fry. Enrichment enhanced growth, but additional enrichment beyond that done during rotifer culture did not increase survival, growth, or condition.

Corn Gluten Meal Partially Replaces Dietary Fish Meal without Compromising Growth or Fatty Acid Composition of Sunshine Bass

AbstractA 7‐week feed trial was conducted to determine the minimum dietary level of menhaden (Brevoortia spp.) meal (MM) needed to maintain growth, fillet quality, and health in sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis). Sunshine bass were stocked at 10 fish/tank (group weight per tank: Mean ± SD = 182.0 ± 2.0 g) into each of 28 tanks and were fed seven experimental diets (4 randomly assigned tanks/diet). Experimental treatments ranged from 0% to 24% MM; corn gluten meal (CGM) was used as the dietary protein replacement. The isonitrogenous diets contained 41% crude protein and 14% crude lipid, and fish were fed to apparent satiation twice daily. Sunshine bass given diets with less than 20% MM had significantly lower (P < 0.05) weight gain than fish in other treatments; however, specific growth rates and feed conversion ratios remained constant in fish fed diets with as little as 16% and 12% MM, respectively. Total n‐3 fatty acids and 20:5(n‐3) content of the fillets were similar between the 20% and 24% MM treatments; however, these fatty acids declined as more MM was replaced. Highly unsaturated fatty acid concentrations in the fillet were similar among diets of at least 16% MM. Collectively, our data provide evidence that MM can be substituted with CGM in diets fed to sunshine bass without adversely affecting growth and fillet quality; however, complete replacement of MM adversely affected growth, lipid metabolism, and oxidative stability in the liver. More effective usage of menhaden resources will enable the industry to create economically and environmentally sustainable diet formulations for sunshine bass.

Use of Turkey Meal as a Replacement for Menhaden Fish Meal in Practical Diets for Sunshine Bass Grown in Cages

AbstractA 391‐d feeding trial was conducted with caged juvenile (mean weight = 36.2 g, SD = 8.04 g) sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis) to evaluate growth, feed conversion, protein efficiency ratio, body composition, and fillet composition resulting from diets with decreasing levels of fish meal (FM; 30, 20, 10, and 0%) and increasing levels of turkey meal (TM; 0.0, 9.7, 17.5, and 26.4%). We stocked 100 randomly selected fish into each of 12 floating cages (3.5 m3). Twice daily, fish were fed all they could consume in 30 min. Four practical diets were formulated to contain 40% protein and to be isoenergetic. After 391 d, significant (P ≤ 0.05) differences were found in growth; fish fed the control diet (30% FM, 0% TM) had higher individual final weight, percent weight gain, and specific growth rate than fish fed 10.0% FM and 17.5% TM. However, differences for those variables were not apparent between the control group and fish fed the 20% FM and 9.7% TM diet or the 0% FM and 26.4% TM diet. Diet composition did not significantly alter amount of diet fed, feed conversion ratio, protein efficiency ratio, percent survival, fillet yield, or hepatosomatic index among treatments. Results indicate that sunshine bass grown in cages for 391 d can be fed a diet containing 0% FM and 26.4% TM without adverse effects on growth, feed conversion ratio, and body composition; more diverse diet formulations for sunshine bass and reduced usage of menhaden fish meal are therefore possible.

Effect of Tank Stocking Density on Larval Sunshine Bass Growth and Survival to the Fingerling Stage

AbstractDetermining optimum parameters for tank culture of sunshine bass (white bass Morone chrysops × striped bass M. saxatilis) fingerlings will facilitate a year‐round supply of seed for the production cycle of this increasingly popular food fish. This experiment determined the relationship between the stocking density of sunshine bass larvae in tanks and their survival rate and size at the time they were trained to accept commercial feeds. Four‐day posthatch (dph) larvae were stocked at 10 densities from 30 to 120 larvae/L in 10‐larvae/L increments. Larvae were initially fed rotifers Brachionus plicatilis cultured with Nannochloropsis spp. algae paste and commercial rotifer feed at 60 rotifers·mL−1·d−1 until 10 dph. Conversion to brine shrimp Artemia spp. began at 7 dph. The daily ration of brine shrimp started at 4/mL and increased by 4/mL every 4 d up to 20/mL. Training to dry starter feed began at 20 dph when 6 g/d of a commercial larval starter meal was offered; 2 d later, salmon starter meal was offered at 8 g/d in 10 equal portions. Photographs of live samples of larvae taken at 4 dph and harvest were used to determine the lengths of the fish. Regression analysis revealed that there was no significant relationship between survival and stocking density. The length and weight of the fish had a linear, negative relationship with stocking density, whereas total tank yield had a curvilinear relationship with stocking density. Under the conditions of this experiment, a stocking density of 87 larvae/L provided the maximum yield.

Influence of Organic Fertilizer Source on Fatty Acid Composition of Zooplankton and Sunshine Bass Fingerlings

AbstractWe evaluated the influence of three organic fertilizers—cottonseed meal, ground rice bran, and ground flaxseed—on the fatty acid composition of zooplankton and fingerling sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis). Flaxseed contains about 10‐fold greater lipid and percent α‐linolenic acid (18:3[n‐3]); values relative to the other two organic fertilizers. Five 0.04‐ha nursery ponds were randomly selected per treatment; 5 d before fish stocking (4 d posthatch; 150,000 fish/ha) and again at day 20 poststocking, ponds were individually fertilized at a rate of 350 kg/ha. After 27 d of culture, zooplankton in the flaxseed treatment contained significantly more 18:3(n‐3) than those in the other fertilizer treatments (10.5% versus ∼7.0%). Likewise, after 40 d of culture, sunshine bass fingerlings reared in ponds fertilized with flaxseed possessed almost twofold higher 18:3(n‐3) (10.7%) than those reared in rice bran (4.7%) and cottonseed (5.8%) treatment ponds. Fish reared in cottonseed meal ponds, however, possessed the highest mean weight (8.2 g versus 6.0 g for flaxseed ponds and 4.8 g for rice bran ponds). We provide evidence that fatty acid composition of organic fertilizers, specifically 18:3(n‐3), significantly influences fatty acid composition of resident zooplankton and sunshine bass fingerlings in nursery ponds.

Influence of Stress and Dietary Natural‐Source Vitamin E on Nonspecific Immunocompetence, Tissue Tocopherol Composition, and Postslaughter Fillet Oxidative Stability in Sunshine Bass

AbstractWe evaluated the effects of stressor exposure and super‐requirement levels of RRR‐α‐tocopheryl acetate (natural‐source vitamin E [NSVE]) on production performance and nonspecific immunocompetency of juvenile sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis). Stressor exposure elicited physiological changes consistent with the generalized stress response, and the magnitude of responses generally mirrored stressor severity. Stressor exposure resulted in lower fillet peroxides and greater aldehydes after short‐term frozen storage, whereas increasing dietary NSVE was associated with a nonsignificant reduction in aldehydes after long‐term storage. Fillet α‐tocopherol content increased linearly with dietary NSVE, exceeding reported tissue levels achieved with synthetic vitamin E (SYNE). Although we observed no significant immunological effects of stress or dietary NSVE content, sampling time and high individual‐to‐individual variation probably restricted our ability to resolve statistical significance. Similar results of vitamin E supplementation have previously been reported; however, the effective dietary concentrations we observed for NSVE are low in comparison with values reported for SYNE. The potential of RRR‐α‐tocopheryl acetate as a highly active vitamin E source for aquaculture feeds warrants further evaluation of the relative suitability of NSVE in meeting the demands of optimal aquaculture nutrition.

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.

Comparison of Insulin-like Growth Factor-I and Insulin-like Growth Factor Binding Protein Concentrations of the Palmetto and Sunshine Bass and the Effects of Gender and Stress

— Plasma concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) were compared between market sized sunshine and palmetto bass. Differences between male and female fish were examined and both hybrids were sampled before and after a low-water confinement stress. There was no difference in body weight between the hybrid types, however, females were significantly heavier than males in both hybrids. Plasma IGF-I concentrations were significantly higher in pre-stressed palmetto bass when compared with sunshine bass, and male palmetto bass had significantly higher IGF-I concentrations than females. Two hours after a 15-min low-water stress, a significant decrease in palmetto bass IGF-I occurred, but there was no change in sunshine bass IGF-I concentrations. Levels of a 33-kDa IGFBP were similar in pre-stressed palmetto bass when compared with sunshine bass; however, no differences due to gender were evident for either hybrid. Two hours after a 15-min low-water exposure, there was no change in the levels of a 33-kDa IGFBP in palmetto or sunshine bass. A more complete understanding of IGF-I, IGFBPs, and IGF-I receptors may be necessary to explain the role of IGF-I in regulating fish growth.