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PubMed1991

Effect of dietary fish oil and corn oil on lipid metabolism and apolipoprotein gene expression by rat liver.

A 3-week fish oil diet induced in weanling rats a decrease in plasma lipids and liver triacylglycerol, and an increase in insulinemia, compared to a corn oil diet. At the same time, plasma apolipoprotein (apo) A-I was slightly lower and plasma heavy apo B/light apo B ratio was higher in fish-oil-fed than in corn-oil-fed rats. Hepatocytes obtained from fish-oil-fed and corn-oil-fed rats were used to examine how fish oil affects lipid and apolipoprotein synthesis and secretion. Primary culture of hepatocytes from fish-oil-fed rats displayed a lower ability to synthesize and secrete triacylglycerol than hepatocytes from corn-fed rats, as measured by mass determination or [U-14C]glycerol incorporation. Hepatocytes from fish-oil-fed rats exhibited a lower synthesis of cholesterol, measured by [14C]acetate incorporation, than hepatocytes from corn-oil-fed rats. This impairment was associated with an increase in beta-oxidation, a higher channeling of oleic acid into phospholipids, and a lower triacylglycerol/diacylglycerol ratio in hepatocytes from fish-oil-fed rats than in hepatocytes from corn-oil-fed rats. Incorporation of [35S]methionine into secreted apoB was reduced in hepatocytes from fish-oil-fed rats, but was not paralleled by a decrease in apo B mRNA. The appearance of degradative forms of apo B suggest an increase in apo B degradation in hepatocytes from fish-oil-fed rats. Incorporation of [35S]methionine into cellular and secreted apo A-I was lower in hepatocytes from fish-oil-fed rats than in hepatocytes from corn-oil-fed rats, and was not paralleled by any difference in the apo A-I mRNA level. Finally, [35S]methionine incorporation into cellular and secreted forms of apo E and apo A-I mRNA were reduced in hepatocytes from fish-oil-fed rats, compared with hepatocytes from corn-oil-fed rats. These combined data show that fish oil diet reduces triacylglycerol synthesis and secretion and affects apo B synthesis at a post-transcriptional level, and reduces cholesterol synthesis and affects apo E and apo A-I synthesis at a transcriptional and a post-transcriptional level.

Animals↗
PubMed1998

Estimates of per capita fish consumption in the U.S. based on the continuing survey of food intake by individuals (CSFII).

This paper presents estimates of daily average per capita fish consumption by age and gender for the 48 conterminous states. The estimated consumption rates are reported for three fish habitats: freshwater/estuarine fish, marine fish, and all fish. The estimates were generated from the combined 1989, 1990, and 1991 Continuing Survey of Food Intake by Individuals (CSFII), a national food consumption survey conducted by the United States Department of Agriculture (USDA). Point and interval estimates of per capita fish consumption were generated from the empirical distribution of daily average per capita consumption. The point estimates include the mean, 50th, 75th, 90th, 95th, and 99th percentiles. Ninety percent confidence intervals are provided for the estimated mean and 90% bootstrap intervals are provided for percentile estimates. Information in a recipe file provided by USDA was used to calculate the amount of fish in recipes which contain fish. The estimated consumption rates are based on the weight of fish in its prepared or "as consumed" condition. The estimated mean consumption rate for all fish for the U.S. population of the 48 conterminous states was 15.65 grams/person/day (C.I.:14.67-16.63) of which 4.71 grams/person/day (C.I.:4.17-5.25) was freshwater/estuarine fish and 10.94 grams/person/day (C.I.:10.14-11.73) was marine fish.

Adolescent↗
PubMed2004

Maternal fish intake in late pregnancy and the frequency of low birth weight and intrauterine growth retardation in a cohort of British infants.

OBJECTIVE: To investigate the relation between maternal fish intake in late pregnancy and the frequency of low birth weight and intrauterine growth retardation (IUGR). PARTICIPANTS: 11 585 pregnant women in south west England. METHODS: Information on fish intake was obtained from a food frequency questionnaire sent to the women at 32 weeks' gestation, and used to calculate n-3 fatty acid (n-3FA) intake from fish. IUGR was defined as a birth weight for gestational age and sex below the 10th centile. Confounding variables considered included maternal age, height, weight, education, parity, smoking and drinking in pregnancy, and whether the mother was living with a partner. Only singleton, liveborn infants were included. MAIN RESULTS: Mean daily intakes of fish and n-3FAs were 32.8 g and 0.147 g respectively. In unadjusted analyses there were positive associations between mean birth weight and fish intake or n-3FA intake, but these disappeared on adjustment for potential confounders. The frequency of IUGR decreased with increasing fish intake-the OR (95%CI) of IUGR in those eating no fish was 1.85 (1.44 to 2.38) compared with those in the highest fish intake group. On adjustment this relation was attenuated (adjusted OR 1.37 (1.02 to 1.84)), but the decline in the frequency of IUGR with increasing fish intake remained statistically significant. No relation was observed between mean gestation and fish or n-3FA intake. CONCLUSIONS: These results lend some support to the hypothesis that raising fish or n3-FA intake during pregnancy may increase fetal growth rate. However, they provide no evidence that increasing fish consumption is associated with an increase in mean gestation.

Analysis of Variance↗
PubMedDate not supplied

Fish consumption and stroke: a community case-control study in Asturias, Spain.

BACKGROUND: The relationship between fish consumption and stroke is controversial. Actually, a low fish consumption may protect against ischemic stroke, while a fish diet is ecologically associated with an increased risk of hemorrhagic stroke. OBJECTIVE: This study seeks to examine the relationship between fish consumption and stroke in a population with a high fish consumption and stroke incidence. METHODS: A population-based case-control study was performed, lasting from September 1990 to December 1991. The study comprised 440 incident cases of stroke and 473 controls between the ages of 40 and 85. Cases were defined following WHO criteria, and controls were randomly selected from the study base population. Information on fish consumption was obtained with a food frequency questionnaire. RESULTS: After controlling for age, energy intake and several stroke risk factors, the risk of stroke increased with the consumption of fish, chi(2) 4.12, p = 0.04. Those in the highest quintile of consumption (46 g of fish/day) had a multivariate adjusted odds ratio (OR) of 1.95 (95% CI: 1.14-3.33) as compared to those in the lowest quintile of fish consumption (11 g/ day). The risk of cerebral infarction also increased with the consumption of fish, showing an OR of 1.98 (95% CI: 1.08-3.47). Those in the highest quintile of n-3 fatty acid consumption (660 mg/day) were at borderline higher risk of stroke, with an OR of 1.76 (95% CI: 0.95-3.26), and also of cerebral infarction (OR: 1.89, 95% CI: 0.95-3.75), as compared to those in the lower quintile of n-3 fatty acids consumption (115 mg/day). CONCLUSION: Although misclassification of exposure and residual confounding by unmeasured factors cannot be ruled out, a high fish consumption was associated with an increased risk of stroke and cerebral infarction in this study. More studies should be done to clarify the effect of fish consumption on stroke and stroke subtype in order to issue recommendations regarding the consumption of fish and the risk of stroke.

Adult↗
PubMed1997

Health advisories for consumers of Great Lakes sport fish: is the message being received?

Nationwide, 45 states issue health advisories for sport fish consumers. Chemical contaminants in some Great Lakes (GL) sport fish include compounds suspected of causing adverse reproductive and developmental effects. Although advisories to reduce consumption of contaminated fish, especially by women, have been issued by GL states (i.e., Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin) since the mid-1970s, little is known about advisory awareness and GL sport fish consumption in the general population. To estimate the prevalence of GL sport fish consumption and health advisory awareness, we conducted a population-based telephone survey of 8,306 adult residents of the eight GL states. We gathered information concerning respondents' demographic characteristics, fish consumption during the preceding year, and sport fish consumption advisory awareness. The survey response rate was 69%. GL sport fish were eaten during the preceding year by 8.4% -95% confidence interval (CI), 7.6-9.2- of adults in the GL states, approximately 4.7 million persons. Women accounted for 43.9% (CI,39. 4-48.4) of consumers. Although 49.9% of GL sport fish consumers were aware of a health advisory, awareness varied significantly by sex: 58.2% (CI, 51.7-64.7) of males and 39.1% (CI, 32.6-45.6) of females were aware. Using logistic regression, we found awareness associated with male sex -odds ratio (OR) = 2.3; CI, 1.5-3.5), white race (OR = 4.2; CI, 1.9-9.1), college degree (OR = 3.1; CI, 1.3-7.6), and consuming >=24 GL sport fish meals/year (OR = 2.4; CI, 1.4-4.3). Only half of GL sport fish consumers reported awareness of a health advisory concerning eating GL sport fish. Awareness was especially low among women, suggesting the need of targeted risk communication programs for female consumers.

Adolescent↗
PubMed1999

The long-term outcome of patients with IgA nephropathy treated with fish oil in a controlled trial. Mayo Nephrology Collaborative Group.

It was reported previously that dietary fish oil supplementation retarded the progression of renal disease in patients with IgA nephropathy in a multicenter, placebo-controlled, randomized, 2-yr clinical trial. The aim of this study was to determine the long-term influence of fish oil treatment on renal progression in observations on the study cohort of 106 patients extending beyond the 2-yr trial. Renal function was assessed by serial serum creatinine and 24-h urine protein measurements. Vital, end-stage renal disease (ESRD), and BP status and treatment beyond completion of the 2-yr trial were determined. As in the trial, the primary end point was an increase of 50% or more in the serum creatinine, and the secondary end point was ESRD. After a mean follow-up of 6.4 yr, 46 patients-17 in the fish oil group versus 29 in the placebo group-reached the primary end point (P = 0.002), and 27 patients-eight in the fish oil group versus 19 in the placebo group-developed ESRD (P = 0.009). At the end of the 2-yr trial, 75 patients (45 fish oil, 30 placebo) remained at risk for the primary end point. This is also when the double-blind part of the trial ended, allowing physicians to stop supplements, switch original placebo-assigned patients to fish oil, and continue fish oil in original fish oil-assigned patients. A significantly greater number of nonsupplemented placebo patients developed the primary end point (P = 0.02) and ESRD (P = 0.003) compared with long-term supplemented fish oil patients. Conversely, more fish oil-supplemented patients had stable renal function than nonsupplemented patients (P = 0.02). By intention, BP control, primarily treated with angiotensin-converting enzyme inhibition, was equal in the fish oil and placebo groups. Proteinuria was modestly reduced in both groups. It is concluded that early and prolonged treatment with fish oil slows renal progression for high-risk patients with IgA nephropathy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2002

The effect of feeding habitats on dietary shifts during the growth in a benthophagous suction-feeding fish.

Several mechanisms of fish ontogenetic dietary shifts, which have important ecological implications, have been proposed. We studied the mechanism of dietary shifts of a benthophagous fish Goniistius zonatus, focusing on the effect of foraging on calcareous algal mat, one of its main feeding substrates, through comparison between two local populations (Morode and Arakashi) with different feeding ecology. The studied fish (11-29 cm SL) fed on various kinds of small invertebrates inhabiting the substrates, using a suctorial feeding mode without visual discrimination towards individual prey. At Morode, gut contents of small fish consisted of more epifaunal and less infaunal organisms than those of large fish, that is, mainly small crustaceans in small fish, and many invertebrates other than crustaceans in large fish. By contrast, at Arakashi, gut contents consisted mostly of epifaunal crustaceans regardless of fish size, i.e., fish showing no dietary shifts. At Morode, G. zonatus took foods mostly from thick calcareous algal mat, whereas fish foraged mainly on thin algal mat and bare rocks at Arakashi, the difference being due to the local differences in the substrate component. The algal mat of Morode harbored much larger amount of infaunal animals than any substrates of Arakashi. At Morode, large fish more forcefully and deeply thrust the mouth into thick algal mat than small fish, and was likely to suck up more infaunal prey using great suctorial force. The comparison clearly indicates that the dietary shifts of G. zonatus at Morode resulted from size-related efficiency in straining foods from heterogeneous micro-topography of thick algal mat.

Animals↗
PubMed2001

Nutritional value of fish meals in the diet for young pigs.

A series of three experiments was conducted to evaluate the nutritional value of fish meals as protein sources in young pigs' diets. Four fish meals (menhaden; mackerel, dried at 85 degrees C and 70 degrees C; and herring, dried at 70 degrees C) were tested. For the first experiment, eight pigs (2 wk old) were surgically fitted with ileal cannulas and used to measure apparent digestibility of the fish meals over the age period of 3 to 7 wk. Compared with menhaden fish meal, mackerel and herring fish meals yielded higher (P < 0.05) ileal digestibility values for threonine, serine, alanine, valine, histidine, lysine, and arginine and also for the average of all amino acids. Ileal digestibility was increased (P < 0.05) as pigs grew. For the second experiment, four different diets each containing different fish meals were fed to 120 pigs to evaluate growth performance over the age period of 3 to 7 wk. Average daily gain was higher (P < 0.07) in pigs fed diets containing either mackerel or herring fish meal than in pigs fed menhaden fish meal during 3 to 5 wk of age and was highest (P < 0.07) in pigs fed a diet containing mackerel fish meal during 5 to 6 wk of age. Gain/feed was higher (P < 0.05) in pigs fed diets containing mackerel and herring fish meals than in pigs fed menhaden fish meal. Mackerel dried at 70 degrees C showed the highest value from the previous two experiments and was chosen to measure the relative bioavailability in comparison to spray-dried porcine plasma. A classical slope-ratio design was used to measure relative bioavailability of mackerel fish meal compared to porcine plasma protein. This study showed that mackerel dried at 70 degrees C can replace spray-dried porcine plasma with the same bioavailability during d 17 to 29 postpartum with additional crystalline lysine and amino acid supplementation to match amino acid profile of the spray-dried porcine plasma.

Animal Feed↗
PubMed2005

Influence of fish oil supplementation on growth and immune system characteristics of cattle.

A study was conducted to determine the effects of supplemental fish oil on growth performance and immune system characteristics of beef calves. The grazing phase (78 d) used 48 yearling crossbred steers (231 +/- 22 kg initial BW) grazing 0.45-ha mixed-grass pastures (four per treatment) supplemented with 1.82 kg/d (as-fed basis) of the diets. Diets consisted of 1) corn-based supplement; 2) corn-based supplement with 1.5% (as-fed basis) fish oil; 3) wheat midd-based supplement; and 4) wheat midd-based supplement with 1.5% fish oil. On d 78, all calves were bled by jugular venipuncture, and blastogenic response of peripheral blood lymphocytes to phytohemagglutinin, concanavalin A, and pokeweed mitogen was measured. Fish oil supplementation negatively affected ADG with the corn-based supplement, but it had no effect when added to the wheat midd-based supplement (base-supplement x fish oil interaction; P < 0.03). Isolated lymphocytes from calves fed the corn-based supplement with fish oil had a greater response to stimulation with concanavalin A than did lymphocytes from calves fed the corn-based supplement alone, but there was no effect of fish oil addition to the wheat midd-based supplement (base-supplement x fish oil interaction; P < 0.01). During the growing phase, the 48 steers (352 +/- 32 kg initial BW) from the grazing phase were moved to drylot pens and were stratified by BW and previous dietary treatment (three calves per pen; eight pens per dietary treatment) for a 56-d growing trial. Dietary treatments consisted of 1) control, and 2) the control diet with 3% (as-fed basis) fish oil. Calves supplemented with fish oil had decreased ADG, ADFI, and G:F (P < or = 0.02) compared with controls. Fish oil supplementation during the grazing phase modulated the immune system; however, the decreased growth performance associated with fish oil in both trials may limit its practical use as an immune stimulant.

Animal Feed↗
PubMed1998

Capacitance microbiology as a means of determining the quantity of spoilage bacteria on fish fillets.

An experiment was conducted to determine if a method for enumeration of Pseudomonas fluorescens in less than 11 h could be used to predict potential spoilage of fresh fish of for species. In each of three separate replications (Rep), five boneless fillets from each species of fish, including rainbow trout (RT), Atlantic salmon (AS), red grouper (RG), and tilapia (T) were obtained fresh from a retail outlet. For each species, six 25-g samples of fish flesh were asceptically removed from each fillet, placed into a polyethylene bag, and stored at 3 degrees C for 0, 1, 2, 3, 4, or 5 days. After storage, samples were analyzed for psychotrophic plate count (PPC), Pseudomonas fluorescens plate counts (PFPC), and P. fluorescens capacitance detection times (PDT) and subjectively evaluated for odor (ODOR). PPC gradually increased on all fish species as storage time increased. In most cases, PFPC decreased slightly and then progressively increased as storage time increased. In Reps 1 and 2, PDT decreased gradually (indicating an increase in bacteria); however, in Rep 3, PDT were erratic and difficult to interpret. Odor increased gradually throughout the storage period for all fish species. Linear correlations (R2 > 0.80) were observed between PPC and day of storage (DAY) for all fish species and Reps except for RT and RG in Rep 3. PFPC correlated (R2 > 0.70) to DAY for all fish except RT in Rep 3 and RG in Rep 2. PDT was negatively correlated to DAY for RT and T in Rep 1 and for all fish in Rep 2. Odor scores were highly correlated (R2 > or = 0.84) to DAY for all fish tested. PPC and PDT were negatively correlated for RT in Reps 1 and 2, AS in Rep 2, and T in Reps 1 and 2. Because results can be obtained in < 12 h, the capacitance procedure with further refinement may provide an excellent alternative to conducting PPC as a means of predicting potential spoilage of fish such that the fillets of inferior quality (i.e., those that will spoil rapidly) may be sent to distribution outlets that are known to move fish products quickly and are able to sell the fish before it spoils.

Animals↗
PubMed1999

Fish as an indicator of eco-system contamination with mercury.

AIM: To compare the total and organic mercury content in sea-fish samples from Croatia, where fishing occurs in a closed part of the Mediterranean Sea, and from other countries fishing mostly in the oceans. METHOD: During 1997, we collected at the Zagreb fish market a total of 115 samples of fifteen kinds of fish including bathypelagic, pelagic and elasmobranch fish, caught in the wider coastal areas of Netherlands, Germany, Spain, Argentina, Belgium, and Croatia. Total mercury and organic methyl-mercury in the fish were determined at the laboratory for testing of food and other common use material at the Zagreb Institute of Public Health. Total mercury was determined by the method of atomic absorption spectrometry. Methyl-mercury was determined by the method of gas chromatography. The mean annual fish consumption in each country was used to calculate the mean weekly intake of mercury and methyl-mercury in each individual country relative to the recommended values. RESULTS: The mean content of total mercury and organic mercury in pooled samples was 111+100 ug/kg and 95+87 ug/kg (85.6%), respectively. The highest values were found in the fish from Croatia (170+124 ug/kg and 150+107 ug/kg; 88.2%, respectively). This concentration did not exceed the maximal allowed level of 500 ug/kg for total and 400 ug/kg for organic mercury in any of the samples examined. The highest values of total mercury (119+111 ug/kg) and organic mercury (103+96 ug/kg; 86.6%) were found in bathypelagic fish. According to the mean annual per capita fish consumption in each country, the mean weekly mercury intake was highest in Spain (49.8 ug) and lowest in Croatia (19.0 ug. CONCLUSION: At present conditions of mercury content and its mean annual consumption, dietary use of sea-fish can still be recommended, even from the seas with closed circulation, such as Adriatic.

Animals↗
PubMed2003

Contamination of fish in streams of the Mid-Atlantic Region: an approach to regional indicator selection and wildlife assessment.

The extent of contamination of fish in the Mid-Atlantic Region was evaluated as part of the U.S. Environmental Protection Agency's Monitoring and Assessment Program's regional assessment in 1993 through 1994. Fish assemblages from wadeable streams were dominated by small, short-lived fishes (e.g., minnows, darters, and sculpins) that were more widely distributed and abundant than large fishes typically chosen for tissue contaminant studies (e.g., trout, black bass, sunfish, common carp). Chemical concentrations in whole-fish homogenates exceeded detection limits for mercury, DDT, and polychlorinated biphenyls (PCBs) in 75 to 100% of the stream length assessed using small fishes and 84 to 100% of the stream length assessed using large fishes. Wildlife values (WVs) representing a threshold for toxic effect were developed to allow examination of the spatial extent of potential risk to piscivorous wildlife. For mercury, DDT, dieldrin, and chlordane, estimates of the regional extent of streams where fish contaminant concentrations exceeded the WVs were greater when based on small fishes than on large fishes. However, within the distribution of stream lengths assessed using small and large fishes, the percentage of stream kilometers exceeding the WVs were quite similar. Our data demonstrate that the greater abundance and distribution of small, short-lived fishes provide greater estimates of regional extent of contamination for first- through third-order streams and can be used for regional assessments of potential exposure and effects in wildlife.

Animals↗
PubMed2004

Dietary fish intake and risk of leukaemia, multiple myeloma, and non-Hodgkin lymphoma.

This study aimed to determine whether fish intake was protective against leukemia, multiple myeloma, and non-Hodgkin lymphoma (NHL), and if our previous finding of a protective effect of fish-related occupations on the risk of these diseases was due to dietary intake of fish. We used data from a population-based case-control study undertaken in Canada in 1994-1998. Dietary information was available for 919 leukemia cases, 287 myeloma cases, 1418 NHL cases, and 4202 controls. The risk of each of the three cancers was determined using multiple logistic regression analysis according to quartiles of weekly fresh fish intake, percentage of total energy intake from fresh fish, and percentage of total fat intake from fresh fish. After adjusting for age, sex, smoking, BMI, and proxy status, people who consumed greater proportions of their total energy intake from fresh fish had a significantly lower risk of each of the three types of cancer, and there was a significant dose-response for risk of leukemia and NHL. Those in the highest quartile for percentage of fat intake from fish were at lowest risk: leukemia odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58-0.89; multiple myeloma OR 0.64, 95% CI 0.45-0.90; NHL OR 0.71, 95% CI 0.60-0.85; and all LH cancers combined OR 0.70, 95% CI 0.61-0.81. The protective effect previously observed for working with fish on the risk of leukemia and lymphoma was independent of fish intake. These findings suggest that a diet high in fish may be protective against lymphohematopoietic cancers and confirm the reduced risk among fish workers.

Animals↗
PubMed2005

Somatic condition of the fish, Notopterus notopterus (Pallas) during different phases of the reproductive cycle.

The study on the mathematical relationship between length and weight of fishes has considerable importance in fishery research especially for the study of fish population dynamics and patterns of growth in fish stocks. This aspect is useful in rationally managing the population of fishes, and is an index of relative robustness of the fish). Variations from expected weight or length of an individual fish or group of fish indicate the general well being and state of gonadal development. The condition of fish can be influenced by the onset of maturity. The results indicate that the overall condition of the female and male fish seems to get improved towards the approach of maturing and mature stages of the gonads during pre-spawning phases. The reduction in the condition factor (K) and somatic condition factor (Ks) during spawning phase may be because of the fish becoming exhausted due to spawning activity. Although improvement in the condition of the fish was observed on the approach of breeding period, the overall condition seems to be better in the aquatic body from which the fish was collected.

Animals↗
PubMed1976

Activities of oxidative enzymes in thyroid follicles of Xiphophorin fishes.

The activity of some intracellular oxidative enzymes was studied histochemically in the cells of the thyroid follicles of teleost fishes of the genus Xiphophorus. The experimental material consisted of animals of the red swordtail and Mexican swordtail breeds of Xiphophorus helleri and of melanotic Xiphophorus maculatus fishes. Observations were carried out on adult specimens of both sexes, including pregnant femals of Mexican swordtail. Moreover, immature Mexican swordtails of both sexes were examined. Thyroid follicles were found to be present in the subpharyngeal region of all fishes studied. The distribution of these follicles as well as their number and form depended on sex, age and on the analysed stage of prenancy. A smaller number and size of thyroid follicles were characteristic of immature specimens, whereas they were most numerous in the thyroids of pregnant fishes. The follicles were arranged in characteristic dense aggregations, especially in the melanotic platyfish. The follicular eipthelium in the fishes under study was usually cubical, but pregnant and non-pregnant adult females also contained a considerable number of larger follicles with flattened epithelium. Besides, thyroid follicles of multilayer epithelium were rather frequently encountered, especially in male fishes, irrespective of their age. The thyroid follicle cells of these fishes demonstrated invariably high activities of reduced NAD and NADP dehydrogenases and of beta-hydroxybutyrate dehydrogenase, and a low activity of succinat dehydrogenase. The intensities of alpha-glycerophosphate and lactate dehydrogenases and of cytochrome oxidase varied with sex, age and breed of the studied fishes. The immature and pregnant fishes showed the most clearly pronounced differences in the intensity of enzymic activity, the thyroid follicles of immature specimens revealing a high activity of lactate dehydrogenase and low activity of cytochrome oxidase, an inverse picture being seen in pregnant fishes. The adult forms of both sexes exhibited an enhanced activity of cytochrome oxidase and a decline in that of lactate dehydrogenase. The observed differences in the intensities of enzymic acitivities in the thyroids of the studied fishes are related with functions of this gland which in the period of growth are different from those in the period of sexual maturity, and certainly also with individual metabolic characteristics of the studied fishes.

Age Factors↗
PubMedDate not supplied

Codon usage in bony fishes.

Bony fishes are excellent experimental models that have been used extensively in biochemical and molecular genetic studies. As proteins are isolated and characterized from these organisms, information on codon usage by bony fishes can be used for subsequent recombinant DNA studies. Codon usage and nucleotide bias within codons from three species of bony fishes and two composites of 14 and 15 bony-fish species were analyzed. Although differences in codon usage increased from seven amino acids between fish species to eight amino acids between fish genera, the small number of differences (3 amino acids) between a single species and a fish composite minus that species suggests that codon usage tables constructed from large numbers of fish species are representative of bony fish in general. Furthermore, we found few differences in codon usage between two vertebrate phyla (fish and rat). Codons in fish DNA sequences end predominantly in G or C, even though the coding sequences are not enriched in these nucleotides. This positional base bias can be used to locate putative protein coding regions in fish DNA sequences.

Amino Acids↗
PubMed1993

Fatty acid composition of serum phosphatidylcholine in healthy subjects consuming varying amounts of fish.

Fatty acid composition of serum phosphatidylcholine was studied in subjects living in the same area and selected for high consumption of fat fish, high consumption of lean fish, moderate or no consumption of fish. The proportion of eicosapentaenoic acid (20:5) in serum phosphatidylcholine was fourfold higher, and that of docosahexaenoic acid (22:6) twofold higher among high consumers of fish compared to non-consumers, and these proportions were also higher in fat fish consumers than in high consumers of lean fish, and in moderate consumers compared to non-consumers. In the whole group the intake of fat fish was correlated to the proportions of 20:5, 22:6 and total n-3 fatty acids in serum phosphatidylcholine. The estimated intake of total n-3 fatty acids from fish was highly correlated to the proportions of these fatty acids in serum phosphatidylcholine (r = 0.87). Plasma triglyceride concentration was lower among high fat fish consumers than in other groups, but no differences between groups were observed for concentration of cholesterol, LDL cholesterol, and HDL cholesterol. It is concluded that subjects who consume high amounts of fat fish in their normal diet attain approximately the same proportions of n-3 fatty acids in serum phosphatidylcholine as reported for subjects taking fish oil supplements, and that fatty acid composition of serum lipids can be used as a marker of intake of fat fish.

Adult↗
PubMed1995

Experiments on second intermediate fish host related cercarial transmission of the eyefluke Diplostomum spathaceum into rainbow trout (Oncorhynchus mykiss).

The effect of host variables such as size and density, on the transmission of cercariae of Diplostomum spathaceum (Rudolphi, 1819) into a second intermediate fish host, rainbow trout, Oncorhynchus mykiss (Walbaum), was studied quantitatively in laboratory experiments under varying exposure conditions. Differences in the number of established metacercariae were noted in differently sized fish exposed singly to the same number of cercariae and in water volumes related to the body surface area of the host. When exposed (1) singly in an equal water volume or, (2) simultaneously in the same tank, no differences in recovery of metacercariae per fish were found between "small" and "large" hosts. The latter observation is valid for three water volumes tested using the same number of cercariae per host. No significant difference in metacercarial infection was revealed in similar sized fish exposed at different host densities. It appears that transmission is more influenced by cercarial density (number of cercariae per water volume) and fish size than by fish density. These experimental findings support the view that cercarial infection of fish occurs by chance, presumably mainly in the gill region. Accordingly, in the field, individual fish size and cercarial density rather than fish population density, prevail in parasite transmission from snail to fish. This is of interest in coastal areas heated by cooling water, where fish growth and fish population density are enhanced.

Animals↗