Hybrid Bass Research Articles

Re-focusing on the Significance of Saxophone's Invention

본 연구는 아돌프 삭스가 처음 색소폰을 만든 때부터 1846년 첫 색소폰 특허를 받을 때까지의 상황을 다양한 문헌조사를 통해 살펴본 것이다. 삭스는 1838년과 1840년 사이에 첫 색소폰을 만들었으며 이는 베이스 색소폰이었다. 1838년은 삭스가 베이스 클라리넷을 처음 제작한 해였음을 감안할 때 삭스가 베이스 색소폰을 만든 것은 베이스 클라리넷이 할 수 없는 역할을 수행할 새로운 저음 악기가 필요하다고 생각했음을 알 수 있다. 새로운 악기를 만들기 위해 삭스는 당시 널리 사용되던 저음 관악기인 오피클라이드도 또 하나의 본보기로 활용하였다. 목관악기인 베이스 클라리넷의 마우스피스와, 금관악기인 오피클라이드의 황동 몸체를 결합시킴으로써 새로운 합성 저음 관악기인 베이스 색소폰이 탄생한 것이다. 이처럼 목관악기의 마우스피스와 금관악기의 몸체가 결합된 베이스 색소폰은 원래 오케스트라에서 저음 목관과 금관악기를 연계하는 중간 역할을 할 것으로 기대되었으며, 이러한 의도는 1846년 첫 색소폰 특허에 포함된 삭스의 설명문에 잘 표명되어 있다. 한 마디로 색소폰은 처음부터 음량이 목관과 금관악기의 중간이면서, 동시에 음색이 거칠고 다루기가 힘든 오피클라이드보다 더 듣기 좋은 소리를 내는 저음 관악기로 만들어졌던 것이다.This study is an attempt to observe the circumstances from the Adolphe Sax`s invention of saxophone to the granting of its patent in 1846 based on various literatures. Sax made his first saxophone, a bass saxophone, between 1838 and 1840. Considering that the year 1838 was when Sax made his first bass clarinet, he made bass saxophone in order to make a different kind of bass wind instrument which can fulfill the certain needs which cannot be expected from the bass clarinet. In order to make such an instrument, Sax made use of Ophicleide, which was a popular bass brass instrument, as another model. Sax combined the mouthpiece of a bass clarinet with the brass body of the ophicleide in order to make a bass saxophone, a new hybrid bass wind instrument. Sax`s original intention, expressed in an ‘Explanation of the first saxophone patent of 1846, was to bridge a gap between the woodwinds and brasses in an orchestra with a new wind instrument equipped with its woodwind mouthpiece and brass body. In a word, from the beginning saxophone was born with its volume of tone in the middle of woodwinds and brasses as well as better quality of tone than rather harsh and unruly ophicleide.

A hybrid Bass–Markov model for the diffusion of a dual-type device-based telecommunication service: The case of WiBro service in Korea

Because the increasing complexity of technology embedded in telecommunication services enables services to be provided via various mediums, the vital requisite for forecasting the diffusion of such services is to simultaneously capture different diffusion phenomena for different devices. This paper proposes a new diffusion model for a dual-type device-based service called the hybrid Bass–Markov model. The proposed model is targeted at the service environment where one type of device is new to the market, and the other type has existing competing services. The Bass model is selected to model service diffusion through the former type of device, while the Markov transition model is employed to capture the diffusion through the latter type of device. The hybrid Bass–Markov model is then developed to produce the aggregate demand. The case of the wireless broadband (WiBro) service in Korea is presented to illustrate the proposed model with a policy sensitivity analysis. This research is expected to be the basis of multi-type device-based service forecasting and, ultimately, will help researchers conduct demand forecasting of services offered by several different devices.

Differential and Gonad Stage-Dependent Roles of Kisspeptin1 and Kisspeptin2 in Reproduction in the Modern Teleosts, Morone Species1

Kisspeptin is an important regulator of reproduction in many vertebrates. The involvement of the two kisspeptins, Kiss1 and Kiss2, and their receptors, Gpr54-1 and Gpr54-2, in controlling reproduction was studied in the brains of the modern teleosts, striped and hybrid basses. In situ hybridization and laser capture microdissection followed by quantitative RT (QRT)-PCR detected coexpression of kiss1 and kiss2 in the hypothalamic nucleus of the lateral recess. Neurons expressing gpr54-1 and gpr54-2 were detected in several brain regions. In the preoptic area, gpr54-2 was colocalized in GnRH1 neurons while gpr54-1 was expressed in cells attached to GnRH1 fibers, indicating two different modes of GnRH1 regulation. The expression of all four genes was measured in the brains of males and females at different life stages using QRT-PCR. The levels of kiss1 and gpr54-1 mRNA, the latter being expressed in minute levels, were consistently lower than those of kiss2 and gpr54-2. While neither gene's expression increased at prepuberty, all were dramatically elevated in mature females. The levels of kiss2 mRNA increased also in mature males. Kiss1 peptide was less potent than Kiss2 in elevating plasma luteinizing hormone levels and in up-regulating gnrh1 and gpr54-2 expression in prepubertal hybrid bass in vivo. In contrast, during recrudescence, Kiss1 was more potent than Kiss2 in inducing luteinizing hormone release, and Kiss2 down-regulated gnrh1 and gpr54-2 expression. This is the first report in fish to demonstrate the alternating actions and the importance of both neuropeptides for reproduction. The organization of the kisspeptin system suggests a transitional evolutionary state between early to late evolving vertebrates.

Temperature and Maternal Effects on Hatch Rate and Length at Hatch of Hybrid Bass (White Bass × Striped Bass) Larvae

AbstractBroodstock selection is an approach that could improve aspects of hybrid bass (white bass Morone chrysops × striped bass M. saxatilis) production. We examined incubation temperature and maternal effects on modal period of incubation (h), hatch rate, and length at hatch. Gametes from three to four white bass dams and one striped bass sire were used to produce hybrids each week for 4 weeks. Eggs from each dam were incubated at 14, 16, 18, and 20°C. The period of incubation, hatch rate, and length at hatch were determined for larvae from each dam × temperature combination. The relationship between incubation period and incubation temperature was exponential, and warmer temperatures resulted in progressively shorter incubation periods and less‐variable hatching duration (i.e., the period from first hatch to last hatch). The effects of incubation temperature and dam explained approximately equal amounts of the variability in length at hatch. Dam weight did not explain a significant amount of variability in modal incubation period, hatch rate, or average length at hatch. Selection for increases in length at hatch could offer improvements to the hybrid bass industry by improving survival in ponds or by eliminating the need for rotifers at first feeding in tanks. The benefits of producing larvae that are larger at hatch should be compared with the effort and cost of a breeding program that selects for length at hatch.

Morphological Models for Identifying Largemouth Bass, Spotted Bass, and Largemouth Bass × Spotted Bass Hybrids

AbstractHybridization is common among many closely related fishes, such as the largemouth bass Micropterus salmoides and spotted bass M. punctulatus. Although these species are common members of the sport fish community in midwestern and southeastern U.S. reservoirs, fairly little is known about their ecological interactions or the potential for the introduction of one species to influence the other species. To address these ecological questions and develop appropriate management strategies, reliable field and laboratory identification of each parental species and their hybrid is required. To that end, we collected juvenile (n = 60) and adult (n = 78) largemouth bass, spotted bass, and largemouth bass × spotted bass hybrids from Lake Norman, North Carolina, a system with a historically strong largemouth bass fishery that recently experienced a spotted bass introduction. We recorded a suite of morphological traits on each individual and correlated those observations with DNA sequences from one mitochondrial marker and three nuclear DNA markers in an attempt to develop morphological field and laboratory methods for identifying individuals of the parental species and their hybrid. After confirming that largemouth bass and spotted bass were hybridizing in Lake Norman, we used classification tree analyses to form dichotomous keys for field and laboratory identification of parental individuals and hybrids at juvenile (50–100 mm total length) and adult (300–500 mm) life stages. These keys should provide fishery biologists and managers with a tool to identify these two species, which commonly interact and closely resemble one another. In addition, these keys should be useful in providing evidence that largemouth bass and spotted bass are hybridizing before more expensive techniques like DNA sequencing are pursued.

Evaluation of Dairy–Yeast Prebiotic Supplementation in the Diet of Juvenile Goldfish in the Presence or Absence of Phytoplankton and Zooplankton

Prebiotics recently have been shown to increase immune responses and disease resistance in certain fish species; therefore, the current study was conducted to evaluate the commercially available dairy-yeast prebiotic, GroBiotic-A, for use with juvenile goldfish Carassius auratus. The study consisted of two 10-week feeding trials in which juvenile goldfish were fed practical diets that were either unsupplemented or supplemented with the dairy-yeast prebiotic at 2% by dry weight. Juvenile fish were sorted by size and stocked into 12 units within each of two culture systems: one indoor system supplied with recirculated well water and one system located outdoors with a continuous flow of pond water to provide a source of phytoplankton and zooplankton. Both diets were fed to fish in six units within each system at the same fixed percentage of body weight twice daily. Culture system (i.e., presence or absence of phytoplankton and zooplankton) was the primary factor influencing (P < 0.0001) percent weight gain, feed efficiency, and survival of goldfish during the feeding trials. No dietary effect was detected, although there was a significant (P < 0.05) interaction between culture system and diet, with supplementation of the dairy-yeast prebiotic tending to improve weight gain and feed efficiency of fish in the presence of phytoplankton/zooplankton. During a controlled disease challenge with an intraperitoneally administered dose of Aeromonas hydrophila that was equivalent to a predetermined LD50 (dose lethal to 50% of test fish), average survival values ranged between 67% and 83% for fish that previously had access to phytoplankton/zooplankton compared with 17-33% for fish that had no access to phytoplankton/zooplankton. The dairy-yeast prebiotic, however, did not enhance resistance of goldfish to the bacterial pathogen and did not greatly alter microbiota of the anterior or posterior gastrointestinal tract based on denaturing gradient gel electrophoresis analysis. In conclusion, the dairy-yeast prebiotic did not improve feed efficiency in goldfish or resistance to a bacterial pathogen as previously observed in golden shiners Notemigonus crysoleucas and hybrid bass (white bass Morone chrysops X striped bass M. saxatilis).

Status of an Introgressed Guadalupe Bass Population in a Central Texas Stream

AbstractIntroductions of nonnative smallmouth bass Micropterus dolomieu into central Texas streams resulted in introgressive hybridization with an endemic allopatric congener, the Guadalupe bass M. treculii. The objectives of this study were to use the variation at 14 microsatellite DNA loci to examine the frequencies of Guadalupe bass, smallmouth bass, and their hybrids 10 years after supplemental stockings of Guadalupe bass in the Blanco River. Genetic analysis identified 40% of individuals as smallmouth bass, 51% as smallmouth bass × Guadalupe bass hybrids, and 9% as other Micropterus hybrids. Pure Guadalupe bass were not collected. Despite supplemental stocking, the frequency of pure Guadalupe bass appears to have declined in the Blanco River in the past 10 years. These results emphasize the need for a current survey of the genetic status of the species throughout its native range.

Development of specific enzyme-linked immunosorbent assay for determining LH and FSH levels in tilapia, using recombinant gonadotropins

We recently produced Oreochromis niloticus recombinant LH and FSH as single-chain polypeptides in the methylotrophic yeast Pichia pastoris. Glycoprotein subunit α was joined with tilapia (t) LHβ or tFSHβ mature protein-coding sequences to form a fusion gene that encodes a ``tethered” polypeptide, in which the gonadotropin β-subunit forms the N-terminal part and the α-subunit forms the C-terminal part. Recombinant (r) gonadotropins were used to develop specific and homologous competitive ELISAs for measurements of FSH and LH in the plasma and pituitary of tilapia, using primary antibodies against rtLHβ or rtFSHβ, respectively, and rtLHβα or rtFSHβα for the standard curves. The wells were coated with either rtLHβ (2 ng/ml) or rtFSHβ (0.5 ng/well), and the final concentrations of the antisera were 1:5000 (for tLH) or 1:50,000 (for tFSH). The sensitivity of the assay was 15.84 pg/ml for tLH and 0.24 pg/ml for tFSH measurements in the plasma, whereas for the measurements in the pituitary, the sensitivity was 2.43 ng/ml and 1.52 ng/ml for tLH and tFSH, respectively. The standard curves for tFSH and tLH paralleled those of serially diluted pituitary extracts of other cichlids, as well as of serially diluted pituitary extract of seabream, European seabass and hybrid bass. We examined plasma tFSH and tLH levels in the course of one reproductive cycle, between two successive spawnings, in three individual tilapia females. Plasma levels of both FSH and LH increased during the second day after the eggs had been removed, probably related to the vitellogenic phase. LH levels increased toward spawning, which occurred on the 11th day. FSH levels also increased on day of cycle, probably due to recruitment of a new generation of follicles for the successive spawning. The development of specific ELISAs using recombinant gonadotropins is expected to advance the study of the distinct functions of each of these important hormones.

Redeye Bass (Micropterus coosae) and Alabama Spotted Bass (M. punctulatus henshalli) Hybridization in Keowee Reservoir

Keowee Reservoir has supported an abundant population of native Micropterus coosae (redeye bass) for over 30 years. Recently, redeye bass abundance in this reservoir declined concomitantly with the establishment of angler-introduced Micropterus punctulatus henshalli (Alabama spotted bass). We suspected declines in redeye bass abundance may be related to their hybridizing with the Alabama spotted bass resulting in offspring that are difficult to differentiate from the Alabama spotted bass. Thus, we collected tissue for genetic analyses from what was thought to be pure redeye bass (Jocassee Reservoir, SC), the original source of Alabama spotted bass (Lake Lanier, GA) stocked in Lake Keowee, and suspected redeye bass x Alabama spotted bass hybrids (Keowee Reservoir, SC) to determine if hybridization might be occurring. These analyses confirmed that hybridization among species of Micropterus had occurred in Keowee Reservoir.

Composition and Consumer Attribute Analysis of Smoked Fillets of Gulf Sturgeon (Ancipenser oxyrinchus desotoi) Fed Different Commercial Diets

ABSTRACT Sturgeons were fed on commercially available diets for hybrid bass, catfish or trout. The impact of these diets on the quality of the smoked fillets was investigated through determination of proximate composition, fatty acid profiles and sensory characteristics. Sensory analysis showed significant differences in moistness, saltiness and acceptability. No significant differences were detected in fattiness and smoked flavor intensity. Proximate analysis revealed an approximate 10% decrease in moisture content together with an estimated 3% salt uptake due to brining and smoking. Results showed that smoking did not adversely affect the fatty acid profile of the fillets. The commercial fish diets tested had no detrimental impact on the composition of the smoked product. Trout and bass diet provided higher levels of EPA and DHA in sturgeon fillets than the catfish diet. Consequently, ratios of ω3-ω6 fatty acids determined for the smoked fillets of sturgeon fed on either bass or trout diet were twice the value determined for the smoked fillets of sturgeon fed on catfish diet.

Comparative Oxygen Consumption and Metabolism of Striped Bass Morone saxatilis and its Hybrid M. chrysops ? xM. saxatilis ?

It has been reported that metabolic rates of striped bass Morone saxatilis and hybrid striped bass M. chrysops♀ x M. saxatilis♂ are different. A series of experiments were conducted to further characterize oxygen consumption and metabolism of striped bass and its hybrid, the sunshine bass. Oxygen consumption was measured to determine standard and routine metabolic rates of striped bass and hybrid striped bass in a freshwater, flow-through tank system. Additionally, blood chemistry stress indicators of the two bass groups were compared in both fresh and brackish water. Hematocrit (% PCV) and hemoglobin were measured in order to compare oxidative efficiencies of the bass. Plasma glucose, chlorides, and cortisol levels were measured to compare the relative stress status of the two bass types reared under experimental conditions. No significant differences were found in average daily oxygen consumption between striped bass and sunshine bass for either standard metabolism (P= 0.92), or routine metabolism (P = 0.86). Standard metabolic rates of oxygen consumption were 69 ± 4.1 and 68 ± 3.5 mg 02/kg3/4 bw/h for sunshine bass and striped bass respectively. Routine metabolic rates were 132 ± 30 and 125 ± 30 mg O2/kg3/4 bw/h for sunshine bass and striped bass respectively. While there were no significant differences in oxygen consumption between species, normal feeding activity generally resulted in increased oxygen consumption by the fish. Striped bass had significantly lower hematocrit values (P= 0.0001), but significantly higher hemoglobin concentrations than sunshine bass maintained in freshwater (P= 0.0001). Striped bass had significantly higher (P= 0.0001) levels of plasma glucose compared to sunshine bass (176 ± 8.6 vs. 103 ± 5.6 mg/dL respectively). Plasma chloride levels for striped bass (123 ± 1.9 mEq/L) were significantly higher (P= 0.041) than plasma chloride levels of sunshine bass (117 ± 1.7 mEq/L). Plasma cortisol levels were significantly higher (P= 0.0081) for striped bass (147 ± 8.4 ng/mL) compared to sunshine bass (119 ± 5.6 ng/ mL) when reared in freshwater. When maintained in brackish water, sunshine bass had significantly higher hematocrit values (P= 0.0001), and hemoglobin concentrations (P= 0.0012) when compared to striped bass. However, sunshine bass had significantly higher hemoglobin concentrations (P= 0.0012) when compared to striped bass. In addition, plasma glucose levels were significantly lower (P = 0.0079) for sunshine bass (79 ± 4.1 g/dL) when compared to striped bass (115 ± 11 g/dL). There were no significant differences between the bass in levels of chlorides or cortisol. No differences were detected in oxygen consumption. However, hybrid striped bass may have more efficient oxidative metabolism due to elevated hemoglobin concentrations. While striped bass hemoglobin values tended to be higher in brackish water than in freshwater, sunshine bass hematocrit or hemoglobin values generally were significantly higher than striped bass in both fresh and brackish water. Based on these results, hybrid striped bass may be capable of directing more energy towards growth than striped bass due to more efficient oxidative metabolism and lower losses of energy related to increased stress.

Influence of Commercial Diets on Quality Aspects of Cultured Gulf of Mexico Surgeon (Ancipenser oxyrinchus desotoi)

ABSTRACT: Cultured sturgeons were fed commercially available diets formulated for hybrid bass, catfish, and trout. The impact of these diets in the quality of the edible muscle was investigated through determination of processing yields, proximate compositions, fatty acid profiles, muscle color, and sensory characteristics. Sturgeon fed the catfish diet were significantly smaller but dressed fillets (percent live weight) were similar for all feeds. Consumer visual acceptability scores were highest for fillets from fish fed the catfish diet, and color differences were determined. Sturgeon fillets from fish fed the trout diet presented a yellowish orange coloration instead of a pale pink coloration. Results show that the diets tested had no detrimental impact in the composition of sturgeon fillets.

A Comparative Study of the Dietary Lysine Requirement of Juvenile Striped bassMorone saxatilisand Sunshine bassM. chrysops x M. saxatilis

AbstractPrevious 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 bassMorone saxatilisand sunshine bassM. 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.

Long-term recovery of PCB-contaminated surface sediments at the Sangamo-westonl Twelvemile Creek/lake Hartwell Superfund Site.

Natural recovery of contaminated sediments relies on burial of contaminated sediments with increasingly clean sediments over time (i.e., natural capping). Natural capping reduces the risk of resuspension of contaminated surface sediments, and it reduces the potential for contaminant transport into the food chain by limiting bioturbation of contaminated surface or near-surface sediments. This study evaluated the natural recovery of surface sediments contaminated with polychlorinated biphenyls (PCBs) at the Sangamo-Weston/Twelvemile Creek/Lake Hartwell Superfund Site (Lake Hartwell), Pickens County, SC. The primary focus was on sediment recovery resulting from natural capping processes. Total PCB (t-PCB), lead-210 (210Pb), and cesium-137 (137Cs) sediment core profiles were used to establish vertical t-PCB concentration profiles, age date sediments, and determine surface sedimentation and surface sediment recovery rates in 18 cores collected along 10 transects. Four upgradient transects in the headwaters of Lake Hartwell were impacted by historical sediment releases from three upgradient sediment impoundments. These transects were characterized by silt/ clay and sand layering. The highest PCB concentrations were associated with silt/clay layers (1.8-3.5% total organic carbon (TOC)), while sand layers (0.05-0.32% TOC) contained much lower PCB concentrations. The historical sediment releases resulted in substantial burial of PCB-contaminated sediment in the vicinity of these four cores; each core contained less than 1 mg/kg t-PCBs in the surface sand layers. Cores collected from six downgradient Lake Hartwell transects consisted primarily of silt and clay (0.91-5.1% TOC) and were less noticeably impacted by the release of sand from the impoundments. Vertical t-PCB concentration profiles in these cores began with relatively low PCB concentrations at the sediment-water interface and increased in concentration with depth until maximum PCB concentrations were measured at approximately 30-60 cm below the sediment-water interface, ca. 1960-1980. Maximum t-PCB concentrations were followed by progressively decreasing concentrations with depth until the t-PCB concentrations approached the detection limit, where sediments were likely deposited before the onset of PCB use at the Sangamo-Weston plant. The sediments containing the maximum PCB concentrations are associated with the period of maximum PCB release into the watershed. Sedimentation rates averaged 2.1 +/- 1.5 g/(cm2 yr) for 12 of 18 cores collected. The 1994 Record of Decision cleanup requirement is 1.0 mg/kg; two more goals (0.4 and 0.05 mg/kg t-PCBs) also were identified. Average surface sedimentation requirements to meet the three goals were 1.4 +/- 3.7, 11 +/- 4.2, and 33 +/- 11 cm, respectively. Using the age dating results, the average recovery dates to meet these goals were 2000.6 +/- 2.7, 2007.4 +/- 3.5, and 2022.7 +/- 11 yr, respectively. (The 95% prediction limits for these values also are provided.) Despite the reduction in surface sediment PCB concentrations, PCB concentrations measured in largemouth bass and hybrid bass filets continue to exceed the 2.0 mg/kg FDA fish tolerance level.

The effect of exogenously administered recombinant bovine somatotropin on intestinal phytase activity andin vivophytate hydrolysis in hybrid striped bassMorone chrysops × M. saxatilis

It has been recently demonstrated that hybrid striped bass Morone chrysops × M. saxatilis exhibit intestinal phytase activity, an enzyme capable of liberating inorganic orthophosphate from the phytate molecule, thereby making phytate phosphorus (PP) available for absorption and utilization by the fish. However, it was also determined that hybrid bass were able to digest only 1–2% of dietary PP. Therefore, an experiment was conducted to determine if exogenously administered recombinant bovine somatotropin (rbST) would increase intestinal phytase activity in hybrid striped bass to a level that would improve PP availability. The results indicate that exogenous rbST treatment, administered either through intraperitoneal injection or orally, does increase intestinal brush border membrane protein concentration. While injection with rbST led to significant increases in both specific brush border membrane and total intestinal phytase activity, oral rbST administration did not cause similar increases. Total P and PP digestibility were not influenced by rbST administration. While treatment with rbST does have the potential to enhance intestinal phytase activity in hybrid striped bass, it does not appear to increase PP digestibility. This observation limits the hormone's utility as an effective technique for improving PP bioavailability to this species.

The effect of growth medium salinity of Photobacterium damselae subsp. piscicida on the immune response of hybrid bass ( Morone saxatilis× M. chrysops)

Photobacterium damselae subsp. piscicida ( P. damselae) was grown on various media and the effect of media salinity on certain immune responses of hybrid bass was studied. In Israel, pasteurellosis outbreaks have not been reported at water salinities below 1.38‰. During vaccination experiments the salinity of the medium on which P. damselae is grown, was shown to affect stimulation of the immune system. No correlation was found between antibody response and protection. Bacterial envelopes separated by electrophoresis and subjected to western blot analysis revealed an antibody response against some protein bands. Band sequencing was performed to identify the protein stimulating the immune response. Sequence identity of 80% was seen in 10-amino-acid overlap of the 36-kDa band with a specific gene of alkalophilic Bacillus firmus. A preparation of P. damselae grown in a 2.5% NaCl medium at 25 °C is the most effective vaccine against pasteurellosis, providing hybrid bass with quite good protection.

The effect of storing hybrid bass ( Morone saxatilis × M. chrysops) sera at freezing temperatures on antibody titers

The effect of storing hybrid bass sera at freezing temperatures on their enzyme-linked immunosorbent assay (ELISA) titers was determined, and the precipitate formed during storage was characterized. Frozen bass sera from fish vaccinated with bacterial sonicate showed no titer in either of two groups—one immunized with bacterial sonicate and the other with sonicate emulsified in adjuvant. Fresh sera exhibited average titers of 1:32 in both groups and 1:20 in convalescent serum. Hybrid bass antisera to bovine serum albumin showed maximum ELISA OD when sera were used after a short storage at 4 °C. Storage at freezing temperatures (−20 and −73 °C) reduced the OD value substantially. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of the cryoprecipitate formed after freezing hybrid bass sera showed protein bands at 85 and 38 kDa, most probably the heavy and light chains, respectively, of bass IgM. Bands at 55, 52, 28, and 26 kDa may represent fibrinogen subunits. It is possible that the cryoprecipitate is composed of a fibrinogen net, which traps the tetrameric IgM molecules and precipitates them during frozen storage.

Tissue essential fatty acid composition and competitive response to dietary manipulations in white bass ( Morone chrysops), striped bass ( M. saxatilis) and hybrid striped bass ( M. chrysops× M. saxatilis)

The effects of wide changes in dietary levels of docosahexaenoic (DHA) or arachidonic (ArA) acids on growth, survival and fatty acid composition in body tissues of Morone larvae were examined. White bass (WB, Morone chrysops), striped bass (SB, Morone saxatilis) and sunshine hybrid bass (HSB, M. chrysops× M. saxatilis) larvae (day 24–46) were fed Artemia nauplii enriched with algal sources of varying proportions of DHA and ArA (from 0 to over 20% of total fatty acids). WB larvae fed DHA-deficient Artemia diet retarded over 50% of their potential growth, however, increasing dietary DHA/ArA ratios were associated with a significant growth improvement. The highest proportion of polyunsaturated fatty acids was found in WB neural tissue (approx. 50% of total fatty acids), while HSB neural tissue contained the highest proportion of saturated fatty acids (approx. 35% of total fatty acids). Within the neural tissues of all Morone larvae, both DHA and ArA were generally the most dominant as well as the most responding fatty acids to dietary manipulations (except in WB fed DHA or ArA deficient diets). HSB neural tissue was particularly efficient in retaining a significant amount of DHA in the face of dietary deficiency. However, WB neural tissue was the most responsive to dietary increase in DHA, accumulating a significantly higher amount of DHA ( P<0.05) than SB or HSB. Results demonstrate significant differences in fatty acid composition and growth responsiveness to dietary manipulations between Morone larvae species and within specific tissues. WB weight gain and neural tissue composition was affected most by dietary changes in both DHA and ArA whereas SB and HSB tissue compositions were generally less affected by dietary manipulations.

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 Km and Vmax 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.

Intestinal phytase II: A comparison of activity and in vivo phytate hydrolysis in three teleost species with differing digestive strategies

Phytates are the primary source of phosphorus in animal feeds of plant origin; however, this phytate phosphorus (PP) is only available to growing fish provided it is released from the phytate molecule as inorganic orthophosphate. Two experiments were conducted to compare phytase activity in the intestinal brush border membrane of carnivorous hybrid striped bass Morone chrysops × M. saxatilis, omnivorous tilapia Oreochromis niloticus × O. aureus and omnivorous koi Cyprinus carpio, and to evaluate the capability of these three species for PP digestibility. The results indicate that tilapia exhibit a significantly higher specific intestinal brush border membrane phytase activity of 5 nmol inorganic phosphate released mg−1 protein min−1 than hybrid bass or koi, which do not differ in their lower activities of 3 nmol inorganic phosphate released mg−1 protein min−1. There were no statistical differences among the three species in terms of total intestinal phytase activity, although the level of total intestinal phytase activity exhibited by the two omnivorous species tended to be higher than that of the carnivorous bass. The tilapia were shown to be capable of digesting substantial amounts of dietary PP, with observed apparent PP digestibility values of 50%. The hybrid bass and the koi could digest only 1–2% of the PP present in the diet. It appears that the only species of the three examined for which intestinal phytase activity is of physiologic significance from a practical standpoint of utilizing dietary PP is tilapia.