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PubMed1992

Estimation of the dietary riboflavin required to maximize tissue riboflavin concentration in juvenile shrimp (Penaeus monodon).

The riboflavin requirements of marine shrimp (Penaeus monodon) were evaluated in a 15-wk feeding trial. Juvenile shrimp (initial mean weight, 0.13 +/- 0.05 g) were fed purified diets containing seven levels (0, 8, 12, 16, 20, 40 and 80 mg/kg diet) of supplemental riboflavin. There were no significant differences in weight gains, feed efficiency ratios and survival of shrimp over the dietary riboflavin range. The riboflavin concentrations in shrimp bodies increased with the increasing vitamin supplementation. Hemolymph (blood) glutathione reductase activity coefficient was not a sensitive and specific indicator of riboflavin status of the shrimp. The dietary riboflavin level required for P. monodon was found to be 22.3 mg/kg diet, based on the broken-line model analysis of body riboflavin concentrations. Shrimp fed unsupplemented diet (riboflavin concentration of 0.48 mg/kg diet) for 15 wk showed signs of deficiency: light coloration, irritability, protuberant cuticle at intersomites and short-head dwarfism.

Animals↗

PubMed1994

Quantification of vitamin C requirements for juvenile shrimp (Penaeus monodon) using polyphosphorylated L-ascorbic acid.

The vitamin C requirements of marine shrimp (Penaeus monodon) for optimal growth were evaluated in a 15-wk feeding trial using polyphosphorylated L-ascorbic acid (C2PP), a stable derivative of L-ascorbic acid (C1). Juvenile shrimp (0.55 +/- 0.01 g) were fed purified diets containing graded levels (0, 50, 100, 200 and 400 mg/kg diet) of supplemental C2PP or a high dosage of C1 (2500 mg/kg diet). Their weight gain, survival, feed efficiency and C1 storage in hepatopancreas and muscle were used to quantify the requirements. The growth of the shrimp fed the unsupplemented diet was significantly lower than those of the supplemented groups except the 100 mg C2PP/kg diet group. The C1 concentrations in muscle and hepatopancreas were greatest in shrimp fed 200 or 400 C2PP mg/kg diet. The dietary level required for juvenile P. monodon was found to be 209 mg/kg diet, based on the broken-line model analysis of weight gain, and was 220 mg/kg diet and 210 mg/kg diet, based on the analyses of C1 concentrations of hepatopancreas and muscle, respectively. Shrimp fed unsupplemented diet showed a significantly higher mortality than the supplemented groups. Most of the shrimp in the unsupplemented group that died suffered incomplete molting. No other overt deficiency sign was observed in any group.

Animals↗

PubMed1994

The dietary requirement of juvenile grass shrimp (Penaeus monodon) for vitamin D.

Two 8-wk experiments were conducted to determine the adequate level of dietary vitamin D for juvenile grass shrimp (Penaeus monodon). In Experiment 1, purified diets with six levels (0, 0.1, 0.5, 2.5, 12.5 and 62.5 mg/kg diet) of supplemental ergocalciferol and cholecalciferol were fed to P. monodon (mean weight 0.19 +/- 0.02 g). In Experiment 2, we used 0, 0.05, 0.1, 0.2, 0.3, 0.6 and 1.0 mg/kg of supplemental cholecalciferol in basal diet fed to the shrimp (mean weight 0.25 +/- 0.03 g). In both experiments, shrimp fed vitamin D-deficient diets grew poorly. In Experiment 1, poorer growth performance was observed in shrimp fed diets containing ergocalciferol compared with those fed the diets containing cholecalciferol. In Experiment 2, weight gain was highest in shrimp fed the diet supplemented with 0.2 mg cholecalciferol/kg diet, followed by the groups fed 0.1 mg/kg, then 0.3 mg/kg, 0.05 and 0.6 mg/kg, 1.0 mg/kg, and finally the unsupplemented control group. The differences among these groups were significant (P < 0.05). The feed efficiency ratio and alkaline phosphatase activity generally followed the same pattern as the weight gain. Analysis by brokenline regression of weight gain and alkaline phosphatase activity of the shrimp in Experiment 2 indicated that the adequate dietary cholecalciferol concentration for growing P. monodon is approximately 0.1 mg/kg.

Alkaline Phosphatase↗

PubMed2001

Molecular characterization and high expression during oocyte development of a shrimp ovarian cortical rod protein homologous to insect intestinal peritrophins.

Penaeoid shrimp oocytes nearing the completion of oogenesis are enveloped in an acellular vitelline envelope and possess extracellular cortical rods (CRs) that extended into the cortical cytoplasm. These cortical specializations are precursors of the jelly layer (JL) of the egg. In searching for highly expressed mRNAs during oogenesis in the marine shrimp (Penaeus semisulcatus), two related cDNAs have been isolated that encode a mature protein of 250 amino acid residues. The deduced amino acid sequences revealed the presence of repeated cysteine-rich domains that are related to the chitin-binding domains of insect intestinal peritrophins. Similar cysteine-rich domains were reported in insect intestinal mucin, crustacean tachycitin, and invertebrate chitinases. The shrimp ovarian peritrophin (SOP) is glycosylated and can bind chitin when extracted from CRs. Its apparent molecular mass in SDS-PAGE is 29-35 kDa and 33-36 kDa, under nonreducing or reducing conditions, respectively. SOP is a major protein of CRs and the JL, and was immunodetected in ovaries; purified CRs; fertilized eggs that were surrounded by a JL matrix; and in the cloudy, whitish flocculent material appearing in sea water immediately after spawning. Immunolocalization in tissue sections determined that SOP was present in oocyte cytoplasm and in extraoocytic CRs. Shrimp expressed SOP mRNA in ovaries at all oocyte developmental stages, whereas expression in the hepatopancreas was restricted to vitellogenic stages. SOP mRNA was abundant in the shrimp ovary and was detected before the presence of the corresponding protein. This is the first demonstration that a protein with similar features to insect intestinal peritrophins is a component of CRs and is therefore a main precursor of the JL of spawned shrimp eggs.

Amino Acid Sequence↗

PubMed2000

Maintenance of androdioecy in the freshwater shrimp, Eulimnadia texana: estimates of inbreeding depression in two populations.

Androdioecy is an uncommon form of reproduction in which males coexist with hermaphrodites. Androdioecy is thought to be difficult to evolve in species that regularly inbreed. The freshwater shrimp Eulimnadia texana has recently been described as both androdioecious and highly selfing and is thus anomalous. Inbreeding depression is one factor that may maintain males in these populations. Here we examine the extent of "late" inbreeding depression (after sexual maturity) in these clam shrimp using two tests: (1) comparing the fitness of shrimp varying in their levels of individual heterozygosity from two natural populations that differ in overall genetic diversity; and (2) specifically outcrossing and selfing shrimp from these same populations and comparing fitness of the resulting offspring. The effects of inbreeding differed within each population. In the more genetically diverse population, fecundity, size, and mortality were significantly reduced in inbred shrimp. In the less genetically diverse population, none of the fitness measures was significantly lowered in selfed shrimp. Combining estimates of early inbreeding depression from a previous study with current estimates of late inbreeding depression suggests that inbreeding depression is substantial (delta = 0.68) in the more diverse population and somewhat lower (delta = 0.50) in the less diverse population. However, given that males have higher mortality rates than hermaphrodites, neither estimate of inbreeding depression is large enough to account for the maintenance of males in either population by inbreeding depression alone. Thus, the stability of androdioecy in this system is likely only if hermaphrodites are unable to self-fertilize many of their own eggs when not mated to a male or if male mating success is generally high (or at least high when males are rare). Patterns of fitness responses in the two populations were consistent with the hypothesis that inbreeding depression is caused by partially recessive deleterious alleles, although a formal test of this hypothesis still needs to be conducted.

Animals↗

PubMed2006

Cross-reactivity among shrimp, crab and scallops in a patient with a seafood allergy.

Shrimp is known to be the most common causative agent in seafood allergy. Patients with shrimp allergy often exhibit allergic symptoms to a variety of seafoods such as crabs and clams. We experienced a 14-year-old girl with shrimp allergy who developed oral swelling and pain accompanied with an uncomfortable feeling after ingestion of scallops followed by intensive exercise. Laboratory investigation showed that she had serum immunoglobulin (Ig)E molecules reacting with several kinds of crustaceans and mollusks, including shrimp, crab and scallops. Immunoblotting revealed that her serum IgE reacted with the 38 kDa bands for shrimp, crab and scallops, suggesting that tropomyosin was the major allergen. Dot-blot inhibition analysis showed a cross-reactivity among shrimp, crab and scallops. We conclude that the cross-reactivity of IgE in this patient resulted from the high homology of tropomyosins.

Adolescent↗

PubMed2006

Structural, immunological and functional properties of natural recombinant Pen a 1, the major allergen of Brown Shrimp, Penaeus aztecus.

BACKGROUND: Recombinant allergens are considered the basis for new diagnostic approaches and development of novel strategies of allergen-specific immunotherapy. As Pen a 1 from brown shrimp Penaeus aztecus is the only major allergen of shrimp and binds up to 75% of all shrimp-specific IgE antibodies this molecule may be an excellent model for the usage of allergens with reduced IgE antibody-binding capacity for specific immunotherapy. AIM: The aim was to clone, express and characterize a full-length recombinant Pen a 1 molecule and compare it with natural Pen a 1 in regard to structural and immunological parameters such as IgE antibody capacity and ability to induce IgE-mediated mediator release. METHODS: Total RNA was isolated from P. aztecus and a rapid amplification of cDNA ends (5' RACE) was performed to obtain full-length cDNA coding for Pen a 1. Using a gene-specific primer, PCR was performed and full-length cDNA was cloned and sequenced. Recombinant His-tagged Pen a 1 was isolated from Escherichia coli under native conditions by immobilized metal affinity chromatography. Secondary structure of natural and recombinant Pen a 1 was compared by circular dichroism (CD) spectroscopy, and the IgE antibody-binding capacity evaluated by RAST. The allergenic potency was tested by the capability of natural and recombinant Pen a 1 to induce mediator release in a murine and human in vitro model of IgE-mediated type I allergy. RESULTS: The deduced amino-acid sequence was 284 residues long and amino-acid sequence identities with allergenic and non-allergenic tropomyosins ranged from 80% to 99% and 51% to 58%, respectively. The analysis of the secondary structure of natural and recombinant Pen a 1 by CD spectroscopic analysis showed that both nPen a 1 and rPen a 1 had alpha-helical conformation that is typical for tropomyosin. The IgE antibody binding capacities of nPen a 1 and r Pen a1 were found to be essentially identical by RAST. The mediator release experiments using both wild-type and humanized rat basophilic leukaemia 30/25 cells showed that rPen a 1 and nPen a 1 induced a similar level of mast cell activation. CONCLUSIONS: Recombinant Pen a 1 and natural Pen a 1 are structurally and immunologically identical and rPen a 1 may be used as the basis for component-resolved diagnosis and the generation of modified shrimp tropomyosin for allergen-specific immunotherapy. The results of the animal studies indicate that C3H/HeJ mice that were sensitized with shrimp extract in combination with cholera toxin as adjuvant may be a suitable model to study shrimp allergy.

Allergens↗

PubMed1996

Molecular phylogeny and in situ detection of the etiologic agent of necrotizing hepatopancreatitis in shrimp.

Necrotizing hepatopancreatitis (NHP) is a severe disease of farm-raised Penaeus vannamei that has been associated with mortality losses ranging from 20 to 95%. NHP was first recognized in Texas in 1985 (S. K. Johnson, p. 16, in Handbook of Shrimp Diseases, 1989) and is an economically important disease that has limited the ability to culture shrimp in Texas. The putative cause of NHP is a gram-negative, pleomorphic, intracellular, rickettsia-like bacterium that remains uncultured in part because of the absence of established shrimp cell lines. The inability to culture the NHP bacterium necessitated the use of molecular methods for phylogenetic placement of the NHP bacterium. The gene encoding the 16S rRNA (16S rDNA) of this shrimp pathogen was amplified by PCR, cloned, and sequenced. Sequence analysis of the cloned 16S rDNA indicates that the NHP bacterium is a member of the alpha subclass of the Proteobacteria. Within the alpha subclass, the NHP bacterium is shown to be most closely related to bacterial endosymbionts of protozoa, Caedibacter caryophila and Holospora obtusa. Also, the NHP bacterium is distinct from but related to members of the typhus group (Rickettsia typhi and R. prowazekii) and spotted fever group (R. rickettsii) of the family Rickettsiaceae. Fluorescently labeled oligonucleotide DNA probes that bind to variable regions (V2, V6, and V8) of 16S rRNA of the NHP bacterium were used to detect the bacterium in infected shrimp by in situ hybridization. This technique provided direct visual evidence that the 16S rDNA that was amplified, cloned, and sequenced was derived from the intracellular bacterium that infects the hepatopancreas of farm-raised P. vannamei shrimp.

Animals↗

PubMed1972

Survival of Vibrio parahaemolyticus in shrimp tissue under various environmental conditions.

Vibrio parahaemolyticus culture O from Gulf Coast shrimp was inoculated into whole shrimp and shrimp homogenate to determine its survival at various temperatures and pH values. Although large decreases in viable population occurred during storage for 2 days at 10 to -18 C, survivors were present even after 8 days. No significant differences were observed in the population changes of inoculated whole shrimp as compared with shrimp homogenates. Low populations (5 x 10(2) per ml) of V. parahaemolyticus were destroyed by heating shrimp homogenates at 60, 80, and 100 C for 1 min. With larger populations (2 x 10(5) per ml), some survivors were present after heating at 60 and 80 C for 15 min. None survived 1 min at 100 C. V. parahaemolyticus was very sensitive to pH values below 6.0. Cells survived for several hours in the contents of the porcine gastrointestinal tract.

Animals↗

PubMed1974

Hydrogen sulfide production by Pseudomonas putrefaciens in shrimp experimentally packed in nitrogen.

Shrimp refrigerated in a nitrogen atmosphere develop off-odors not typical of normal spoilage. Investigations of this phenomenon showed that hydrogen sulfide developed in the headspace gas, and a large percentage of the microbial population present on the shrimp stored in nitrogen was capable of hydrogen sulfide production, in contrast to the flora on shrimp stored in air. The predominant hydrogen sulfide-producing organism, Pseudomonas putrefaciens, was present in low numbers on fresh shrimp but usually reached high numbers by day 8 of nitrogen storage. Further studies revealed that cysteine and cystine were the probable substrates in shrimp utilized by this organism for hydrogen sulfide production. When shrimp sterilized by irradiation were inoculated with P. putrefaciens and incubated in an atmosphere of nitrogen, hydrogen sulfide and the characteristic off-odors developed.

Air↗

PubMed2006

PmRab7 is a VP28-binding protein involved in white spot syndrome virus infection in shrimp.

Our aim was to isolate and characterize white spot syndrome virus (WSSV)-binding proteins from shrimp. After a blot of shrimp hemocyte membrane proteins was overlaid with a recombinant WSSV envelope protein (rVP28), the reactive bands on the blot were detected using anti-VP28 antibody. Among three membrane-associated molecules identified by liquid chromatography-tandem mass spectrometry, there was a 25-kDa protein that bound to both rVP28 and WSSV. Since it had a primary structure with high homology to the small GTP-binding protein Rab7, we named it Penaeus monodon Rab7 (PmRab7). The full-length PmRab7 cDNA was obtained, and results from a glutathione S-transferase pull-down assay confirmed specific binding to rVP28. Reverse transcriptase PCR analysis revealed PmRab7 expression in many tissues, and real-time PCR analysis revealed that expression was constitutive. Binding of PmRab7 to rVP28 or WSSV occurred in a dose-dependent manner and was inhibited by anti-Rab7 antibody. In an in vivo neutralization assay, the number of dead shrimp after challenge with WSSV plus PmRab7 (15%) or WSSV plus anti-Rab7 antibody (5%) was significantly lower than after challenge with WSSV alone (95%). In contrast to the WSSV-injected group, shrimp injected with WSSV plus PmRab7 or WSSV plus anti-Rab7 showed no WSSV-type histopathology. We conclude that PmRab7 is involved in WSSV infection in shrimp. This is the first study to identify a shrimp protein that binds directly to a major viral envelope protein of WSSV.

Amino Acid Sequence↗

PubMed2006

Insights into the immune transcriptome of the shrimp Litopenaeus vannamei: tissue-specific expression profiles and transcriptomic responses to immune challenge.

Infectious disease constitutes a major obstacle to the sustainability of shrimp aquaculture worldwide and a significant threat to natural populations of shrimp and other crustacea. The study of the shrimp immune system, including the response to viral infection, has been hampered by a relative lack of molecular genetic information and of tools suitable for high-throughput assessment of gene expression. In this report, the generation of a cDNA microarray encompassing 2,469 putative unigenes expressed in gills, circulating hemocytes, and hepatopancreas of Litopenaeus vannamei is described. The unigenes printed on the microarray were derived from the analyses of 7,021 expressed sequence tags obtained from standard cDNA libraries as well as from libraries generated by suppression subtractive hybridization, after challenging shrimp with a variety of immune stimuli. The general utility of the cDNA microarray was demonstrated by interrogating the array with labeled RNA from four different shrimp tissues (gills, hemocytes, hepatopancreas, and muscle) and by analyzing the transcriptomic response of shrimp to a lethal challenge with white spot syndrome virus. Our results indicate that white spot syndrome virus infection upregulates (in the hepatopancreas) genes encoding known and potential antimicrobial effectors, while some genes involved in protection from oxidative stress were found to be downregulated by the virus.

Animals↗

PubMed1998

Tail-flip mechanism and size-dependent kinematics of escape swimming in the brown shrimp crangon crangon

Tail-flip escape swimming by the brown shrimp Crangon crangon has been investigated across a range of body lengths (11-69 mm) using high-speed video analysis. This has revealed several novel aspects of the tail-flip mechanism when compared with that of other decapod crustaceans that have been studied. (i) The pattern of body flexion in C. crangon produces movement of the cephalothorax as well as the abdomen about the centre of mass. (ii) Shrimps form a 'head-fan' with their antennal scales, in addition to the tail-fan formed by their uropods, apparently for generating thrust during tail-flips. (iii) Shrimps typically swim on their side rather than in an upright body position. It is suggested that these features may be interlinked and derive from habitat specialisation. The kinematic properties of tail-flips were found to vary with shrimp size. As shrimp body length increased, the rate of body flexion and re-extension decreased whilst the duration of tail-flips increased. Mean (and maximum) velocity estimates ranged between 0.4 m s-1 (0.7 m s-1) and 1.1 m s-1 (1.8 m s-1) for shrimps of different sizes. The combined effects of escape behaviour and size-dependent variability in tail-flip kinematics will have important implications with regard to predation risk.

Journal Article↗

PubMed1999

Escape trajectories of the brown shrimp crangon crangon, and a theoretical consideration of initial escape angles from predators

Tail-flip escape trajectories of the brown shrimp Crangon crangon have been investigated in response to a natural predator, the cod Gadus morhua, and an artificial stimulus. Shrimps escaped by rolling to their left or right during the initial tail-flip of a response, and thereafter swam on their side. As a result of the laterally directed first tail-flip, initial escape angles always lay between 75 degrees and 156 degrees with respect to the (pre-escape) longitudinal axis (anterior=0 degrees) of the shrimp. Symmetrical attacks from either head-on or tail-on produced escapes to the shrimp's left or right in equal proportions, although a contralateral bias did occur if the shrimp experienced a looming object from one side before a symmetrical attack was applied. Lateral attacks produced a significantly greater proportion of contralateral responses than ipsilateral ones. Empirical and theoretical analyses indicate that the initial escape direction is influenced by an interaction between the range of first tail-flip escape angles that the shrimp is capable of performing and the risk of being intercepted by a predator during the initial stage of an escape. Thus, the unpredictability ('protean behaviour') of the response may be affected by the conditions of the interaction. Subsequent tail-flips of an escape usually directed the response away from the stimulus, but sometimes escapes were instead steered to the side of the stimulus and then behind it. The probability of each type of escape occurring changed with attack direction. The elements of protean behaviour that have been identified in both the initial and subsequent stages of the escape may prevent predators from learning a fixed pattern of response, but a trade-off occurs when escape trajectories infringe upon zones of high capture risk.

Journal Article↗

PubMed1998

Effects of dietary shrimp, squid and octopus on serum and liver lipid levels in mice.

The effects of three seafoods, shrimp, squid and octopus, on lipid metabolism were investigated in mice fed on 0.1% and 1.0% cholesterol-supplemented diets in the first experiment. One of each of these seafoods and casein were added to the basal diet at levels of 15% and 5%, respectively, as proteins. Casein served as the sole protein source of the control diet. The serum cholesterol concentration was significantly lower in the mice fed on shrimp and squid in the 0.1% cholesterol diet and on any seafood in the 1.0% cholesterol diet when compared with that in the mice fed on the control diet. The liver cholesterol concentration was significantly lower in all seafood groups given the 0.1% cholesterol diet, and in the squid and octopus groups given the 1.0% cholesterol diet. In the second experiment, the effect of these seafoods on lipid metabolism was compared with that of their defatted products in mice fed on a 0.2% cholesterol diet. Defatting resulted in an increase in the serum cholesterol and triglyceride levels in the shrimp and squid groups. The hepatic cholesterol concentration in all the seafood groups was significantly lower than that in the control group, and defatting did not influence the liver cholesterol concentration. Fecal total steroid excretion was higher in all the seafood groups when compared with that in the control group, and was not modified by the removal of fats. Thus, shrimp, squid and octopus exerted hypolipidemic activity; the serum cholesterol-lowering activity of shrimp and squid was attributed to their lipid fraction, whereas the non-lipid fraction of shrimp, squid and octopus contributed to a reduction of hepatic cholesterol and an increase of fecal steroid excretion.

Animal Nutritional Physiological Phenomena↗

PubMed2000

Long-term pyrene exposure of grass shrimp, Palaemonetes pugio, affects molting and reproduction of exposed males and offspring of exposed females.

The objective of this study was to investigate the impact of long-term pyrene exposure on molting and reproduction in the model estuarine invertebrate, the grass shrimp (Palaemonetes pugio). Grass shrimp were exposed to measured concentrations of 5.1, 15.0, and 63. 4 ppb (microg/L) pyrene for 6 weeks, during which time we determined molting and survivorship. At the end of the exposure, we immediately sacrificed some of the shrimp for biomarker (CYP1A and vitellin) analyses. The remaining shrimp were used to analyze fecundity and embryo survivorship during an additional 6 weeks after termination of pyrene exposure. Male shrimp at the highest pyrene dose (63 ppb) experienced a significant delay in molting and in time until reproduction, and showed elevated ethoxycoumarin o-deethylase (ECOD) activity immediately after the 6-week exposure period. In contrast, 63 ppb pyrene did not affect these parameters in female shrimp. Females produced the same number of eggs per body weight, with high egg viability (98-100%) at all exposure levels, but with decreased survival for the offspring of the 63-ppb pyrene-exposed females. In addition, vitellin levels were elevated only in females at 63 ppb pyrene after the 6-week exposure. We hypothesize that the elevated vitellin binds pyrene and keeps it biologically unavailable to adult females, resulting in maternal transfer of pyrene to the embryos. This would account for the lack of effect of pyrene exposure on ECOD activity, molting, and reproduction in the adult females, and for reduced survival of their offspring.

Animals↗

PubMed1990

The midgut trypsins of shrimp (Penaeus monodon). High efficiency toward native protein substrates including collagens.

Two shrimp trypsins have been purified from the midguts of Penaeid shrimps by various chromatographies and HPLC. The molecular masses of them are 27 and 29 kDa, respectively. They show the typical specificity of trypsin for substrates and inhibitors, and their N-terminal amino-acid sequences are homologous to those of other trypsins. The shrimp enzymes are very acidic (pI less than or equal to 2.4), and show distinctively low Km for the synthetic amide substrates. They also hydrolyse various native proteins more efficiently than bovine trypsin in vitro. However, the anionic shrimp trypsins do not have special preference for basic protein substrates over the acidic one. Collagenolytic activity of the midgut extract was mainly due to serine proteases. The collagenolytic activity of the purified shrimp trypsin was confirmed by assays with either soluble or insoluble native type I collagens. In comparison with the other trypsins from the Crustacean decapods, the shrimp enzymes have four pairs of disulfide bonds, intermediary between the crayfish trypsin (three pairs) and the crab trypsin (five pairs), and are immunochemically different from them.

Amino Acid Sequence↗

PubMed2006

Impact of exposure to bacteria on metabolism in the penaeid shrimp Litopenaeus vannamei.

We hypothesized that aggregation of bacteria and hemocytes at the gill, which occurs as part of the shrimp's antibacterial immune defenses, would impair normal respiratory function and thereby disrupt aerobic metabolism. Changes in oxygen uptake and lactate accumulation were determined in Litopenaeus vannamei, the Pacific white shrimp, following injection with either saline (control) or a strain of the gram-negative bacterium Vibrio campbellii that is pathogenic in crustaceans. The rate of oxygen uptake was determined during the first 4 h after injection and after 24 h. Injection of bacteria decreased oxygen uptake by 27% (from 11.0 to 8.2 micromol g-1 h-1) after 4 h, while saline-injected shrimp showed no change. Decreased oxygen uptake persisted 24 h after Vibrio injection. In well-aerated water, resting whole-animal lactic acid levels increased in shrimp injected with bacteria (mean=2.59 micromol lactate g-1+/-0.39 SEM, n=8) compared to saline-injected control shrimp, but this difference did not persist at 24 h. Exposure to hypercapnic hypoxia (PCO2=1.8 kPa, PO2=6.7 kPa) also resulted in significant whole-body lactic acid differences (mean=3.99 and 1.8 micromol g-1 tissue in Vibrio and saline-injected shrimp, respectively). Our results support the hypothesis that the crustacean immune response against invading bacteria impairs normal metabolic function, resulting in depression of oxygen uptake and slightly increased anaerobic metabolism.

Animals↗