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PubMed1996

Effects of fish oil on oxidation resistance of VLDL in hypertriglyceridemic patients.

In hypertriglyceridemic (HTG) patients the addition of fish oil to the diet causes a marked reduction in the concentration of triglyceride-rich lipoproteins in the serum. To investigate the effects of fish oil on the oxidation resistance of VLDL and LDL in HTG patients, nine male patients received 1 g/d fish oil (containing 55.7% n-3 polyunsaturated fatty acids [PUFAS] and l U alpha-tocopherol/g fish oil) for 6 weeks followed by 5 g/d fish oil for an additional 6 weeks. Cu(2+)-induced oxidation of VLDL and LDL was measured by continuous monitoring of conjugated dienes. Supplementation with 1 g/d fish oil caused hardly any changes in the n-3 PUFA content of lipoproteins or lipoprotein concentrations in serum. However, supplementation with 5 g/d fish oil resulted in a significant increase of n-3 PUFA content in VLDL (from 2.5% to 6.4% of total fatty acids) and LDL (from 3.2% to 6.4% of total fatty acids), decreases in serum triglyceride, VLDL triglyceride, and VLDL cholesterol concentrations of 54%, 56%, and 40%, respectively, and an increase in LDL cholesterol of 23%. The lag times of VLDL and LDL oxidation decreased from 197 to 140 minutes (-29%) and 101 to 86 minutes (-15%), respectively. At the end of the 5 g/d fish oil supplementation the lag times of VLDL and LDL oxidation were correlated with their respective n-3 PUFA content (r = -.67; P < .05 and r = -.79; P < .02, respectively). Before and at the end of supplementation with 5 g/d fish oil the lag times and propagation rates of VLDL oxidation also correlated with the total number of double bonds in all PUFAs of VLDL. We conclude that fish oil supplementation strongly reduces serum concentrations of total triglycerides, VLDL triglycerides, and VLDL cholesterol. However, in HTG patients fish oil supplementation increased the serum LDL cholesterol concentration and the susceptibility of VLDL and LDL to oxidation.

Adult↗
PubMed2004

Accumulated evidence on fish consumption and coronary heart disease mortality: a meta-analysis of cohort studies.

BACKGROUND: Results from observational studies on fish consumption and coronary heart disease (CHD) mortality are inconsistent. METHODS AND RESULTS: A meta-analysis of cohort studies was conducted to examine the association between fish intake and CHD mortality. Studies were included if they provided a relative risk (RR) and corresponding 95% CI for CHD mortality in relation to fish consumption and the frequency of fish intake. A database was developed on the basis of 11 eligible studies and 13 cohorts, including 222 364 individuals with an average 11.8 years of follow-up. Pooled RR and 95% CI for CHD mortality were calculated by using both fixed-effect and random-effect models. A linear regression analysis of the log RR weighted by the inverse of variance was performed to assess the possible dose-response relation. Compared with those who never consumed fish or ate fish less than once per month, individuals with a higher intake of fish had lower CHD mortality. The pooled multivariate RRs for CHD mortality were 0.89 (95% CI, 0.79 to 1.01) for fish intake 1 to 3 times per month, 0.85 (95% CI, 0.76 to 0.96) for once per week, 0.77 (95% CI, 0.66 to 0.89) for 2 to 4 times per week, and 0.62 (95% CI, 0.46 to 0.82) for 5 or more times per week. Each 20-g/d increase in fish intake was related to a 7% lower risk of CHD mortality (P for trend=0.03). CONCLUSIONS: These results indicate that fish consumption is inversely associated with fatal CHD. Mortality from CHD may be reduced by eating fish once per week or more.

Animals↗
PubMed1995

Fish oil treatment decreases superoxide anions in the myocardium and coronary arteries of atherosclerotic monkeys.

BACKGROUND: This experiment sought to determine the effects of fish oil on superoxide anion production in the myocardium and coronary arteries of atherosclerotic monkeys. Recent evidence indicates that dietary supplementation with fish oil preserves normal vasomotion of atherosclerotic coronary arteries and reduces damage to the myocardium after ischemia and reperfusion, although the mechanisms remain unclear. METHODS AND RESULTS: Adult male cynomolgus monkeys were fed an atherogenic diet with (n = 15) or without (n = 15) half the fat calories from fish oil. After 12 months, chemiluminescence of lucigenin was used to measure superoxide anion production in coronary arteries and myocardium after 1 hour of ischemia and 2 hours of reperfusion. The signals were calibrated with known quantities of xanthine and xanthine oxidase. Superoxide anion production in ischemic myocardium was (mean +/- SEM, nmol/mg dry wt per minute) 1 +/- 1 and 4 +/- 1 in monkeys fed fish oil and not fed fish oil, respectively (P < .05). Superoxide anion production in coronary arteries not exposed to ischemia and reperfusion was (nmol/mg dry wt per minute) 4 +/- 1 and 8 +/- 2 in monkeys fed fish oil and not fed fish oil, respectively (P < .05). Superoxide anion production in coronary arteries was (nmol/mg dry wt per minute) 5 +/- 2 and 16 +/- 3 in monkeys fed fish oil and not fed fish oil after ischemia and reperfusion, respectively (P < .05). CONCLUSIONS: Dietary supplementation with fish oil reduced vascular superoxide anion production and prevented the increase in vascular and myocardial superoxide anion production that accompanied ischemia and reperfusion. These phenomena may underlie some of the beneficial cardiovascular effects of fish oil.

Acridines↗
PubMed1998

Effects of dietary fish and weight reduction on ambulatory blood pressure in overweight hypertensives.

Obesity is a major factor contributing to hypertension and increased risk of cardiovascular disease. Regular consumption of dietary fish and omega3 fatty acids of marine origin can lower blood pressure (BP) levels and reduce cardiovascular risk. This study examined the potential effects of combining dietary fish rich in omega3 fatty acids with a weight loss regimen in overweight hypertensive subjects, with ambulatory BP levels as the primary end point. Using a factorial design, 69 overweight medication-treated hypertensives were randomized to a daily fish meal (3.65 g omega3 fatty acids), weight reduction, the 2 regimens combined, or a control regimen for 16 weeks. Sixty-three subjects with a mean+/-SEM body mass index of 31.6+/-0.5 kg/m2 completed the study. Weight fell by 5.6+/-0.8 kg with energy restriction. Dietary fish and weight loss had significant independent and additive effects on 24-hour ambulatory BP. Effects were greatest on awake systolic and diastolic BP (P<0.01); relative to control, awake pressures fell 6.0/3.0 mm Hg with dietary fish alone, 5.5/2.2 mm Hg with weight reduction alone, and 13.0/9.3 mm Hg with fish and weight loss combined. These results also remained significant after further adjustment for changes in urinary sodium, potassium, or the sodium/potassium ratio, as well as dietary macronutrients. Dietary fish also significantly reduced 24-hour (-3.1+/-1.4 bpm, P=0.036) and awake (-4.2+/-1.6 bpm, P=0. 013) ambulatory heart rates. Weight reduction had a significant effect on sleeping heart rate only (-3.2+/-1.7 bpm, P=0.037). Combining a daily fish meal with a weight-reducing regimen led to additive effects on ambulatory BP and decreased heart rate. The effects were large, suggesting that cardiovascular risk and antihypertensive drug requirements are likely to be reduced substantially by combining dietary fish meals rich in omega3 fatty acids with weight-loss regimens in overweight medication-treated hypertensives. The reduction in heart rate seen with dietary fish suggests a cardiac/autonomic component, as well as vascular effects, of increased consumption of omega3 fatty acid from fish.

Adult↗
PubMed2006

Evolution and origin of vomeronasal-type odorant receptor gene repertoire in fishes.

BACKGROUND: In teleost fishes that lack a vomeronasal organ, both main odorant receptors (ORs) and vomeronasal receptors family 2 (V2Rs) are expressed in the olfactory epithelium, and used for perception of water-soluble chemicals. In zebrafish, it is known that both ORs and V2Rs formed multigene families of about a hundred copies. Whereas the contribution of V2Rs in zebrafish to olfaction has been found to be substantially large, the composition and structure of the V2R gene family in other fishes are poorly known, compared with the OR gene family. RESULTS: To understand the evolutionary dynamics of V2R genes in fishes, V2R sequences in zebrafish, medaka, fugu, and spotted green pufferfish were identified from their draft genome sequences. There were remarkable differences in the number of intact V2R genes in different species. Most V2R genes in these fishes were tightly clustered in one or two specific chromosomal regions. Phylogenetic analysis revealed that the fish V2R family could be subdivided into 16 subfamilies that had diverged before the separation of the four fishes. Genes in two subfamilies in zebrafish and another subfamily in medaka increased in their number independently, suggesting species-specific evolution in olfaction. Interestingly, the arrangements of V2R genes in the gene clusters were highly conserved among species in the subfamily level. A genomic region of tetrapods corresponding to the region in fishes that contains the V2R cluster was found to have no V2R gene in any species. CONCLUSION: Our results have indicated that the evolutionary dynamics of fish V2Rs are characterized by rapid gene turnover and lineage-specific phylogenetic clustering. In addition, the present phylogenetic and comparative genome analyses have shown that the fish V2Rs have expanded after the divergence between teleost and tetrapod lineages. The present identification of the entire V2R repertoire in fishes would provide useful foundation to the future functional and evolutionary studies of fish V2R gene family.

Animals↗
PubMedDate not supplied

Potential health risks of recreational fishing in new york city.

BACKGROUND: Fish in the rivers around New York City are contaminated with polychlorinated biphenyls (PCBs) that have been increasingly associated with neurodevelopmental abnormalities. The New York State Department of Health has recommended that the consumption of fish from the rivers around New York City not exceed one meal per month and that no pregnant women or children less than 15 years of age eat any fish from these waters. DESIGN/METHODS: We systematically surveyed anglers at Manhattan fishing sites over a 3-month period to estimate the exposure of anglers, children, and women of childbearing age to PCB-laden fish. RESULTS: One hundred sixty anglers completed the interview. Eighty percent of these anglers were unaware of any advisory to limit fish consumption in order to limit PCB exposure. Most anglers ate the fish they caught. Of the anglers who said that they took the fish home (72.5% of the total sample), 17.7% reported that children regularly eat the fish, and 15.4% reported that an individual had been pregnant while regularly eating the fish. CONCLUSION: Despite state advisories, New York City anglers report high rates of fish consumption by themselves, pregnant women, and children. Although determining the consequences of such consumption will require further study, this represents a worrisome environmental exposure.

Adult↗
PubMed1999

Mortality of fish fry as a result of specific and aspecific cercarial invasion under experimental conditions.

Although the effect exerted on fish by fluke cercariae developing in fish as intermediate hosts is fairly well known, cercariae of flukes requiring intermediate hosts other than fish occur in fish ponds in much higher numbers. To study the effect of these latter cercariae on fish fry, a few days old common carp fry (Cyprinus carpio) were exposed to cohorts of xiphidiocercariae or echinocercariae shed by one or two snails acting as intermediate hosts. The observed pathogenicity of these cercariae was compared to the well-known pathogenic effect of Diplostomum cercariae. Although Diplostomum cercariae proved to be the most pathogenic, occasionally also the other two types of cercariae could kill the common carp fry by invading their body. Xiphidiocercariae ingested by the fish penetrated the intestinal wall and developed into metacercariae within the body of the fry. They could also get into the musculature through the skin. The much larger echinocercariae invaded the gill cavity where they became encapsulated, thus hampering gill function and leading to fish mortality due to oxygen deficiency. Diplostomum cercariae were more pathogenic than the cercariae of the other two flukes in that they were shed by the intermediate host in very large numbers. Although much less xiphidiocercariae and echinocercariae emerged from the intermediate host snails than Diplostomum cercariae, the former could kill the fish fry already in lower numbers. These findings prove that fluke cercariae nonspecific to fish may exert pathogenic effects on fish, and presumably contribute to the early mortality of young fry placed out into fish ponds.

Animals↗
PubMed1996

Fish oil in diabetic nephropathy.

OBJECTIVE: Recent studies in nondiabetic kidney diseases suggest that dietary supplementation with n-3 polyunsaturated fatty acids (fish oil) may have beneficial effects on albuminuria, kidney function, arterial blood pressure, and dyslipidemia. Therefore, we evaluated the long-term effect of fish oil in diabetic nephropathy. RESEARCH DESIGN AND METHODS: A 1-year double-blind randomized controlled study comparing fish oil (4.6 g n-3 fatty acids/day) with placebo (olive oil) was performed in an outpatient clinic in a tertiary referral center. Thirty-six normotensive IDDM patients with diabetic nephropathy were included; 18 were treated with fish oil. Seven patients dropped out (four received fish oil), and results for the remaining 29 are presented. Albuminuria (enzyme immunoassay), glomerular filtration rate (51Cr-labeled EDTA plasma clearance), 24-h ambulatory blood pressure, and lipid profile were determined every 6 months. RESULTS: Albuminuria increased by 22% (1-46%) (mean [95% CI]) in the fish oil group vs. 15% (-11-49%) in the placebo group (NS). Glomerular filtration rate decreased from 116 +/- 7 to 105 +/- 7 ml.min-1.1.73 m-2 (mean +/- SE) vs. from 108 +/- 6 to 103 +/- 7, fish oil and placebo, respectively (NS). No significant changes occurred in 24-h ambulatory blood pressure: from 141 +/- 4/82 +/- 2 mmHg to 142 +/- 5/83 +/- 2 vs. from 140 +/- 4/78 +/- 2 to 144 +/- 4/80 +/- 3, fish oil and placebo, respectively (NS). In the fish oil group, serum triglycerides (median [range]) decreased from 0.97 (0.5-4.0) mmol/l to 0.8 (0.4-3.0) vs. from 1.01 (0.4-2.0) to 1.09 (0.4-2.0) in the placebo group (P < 0.05) and VLDL cholesterol decreased from 0.45 (0.23-1.88) to 0.37 (0.21-1.43) mmol/l vs. from 0.44 (0.21-0.94) to 0.41 (0.17-1.94) (P < 0.05), but total and LDL cholesterol rose in the fish oil compared with the placebo group. CONCLUSIONS: Our study does not suggest that fish oil has beneficial effects on albuminuria, kidney function, blood pressure, and dyslipidemia in normotensive IDDM patients suffering from diabetic nephropathy.

Adult↗
PubMed2004

The effect of dietary fish oil supplementation on exercising horses.

Ten horses of Thoroughbred or Standardbred breeding were used to study the effects of dietary fish oil supplementation on the metabolic response to a high-intensity incremental exercise test. Horses were assigned to either a fish oil (n = 6) or corn oil (n = 4) treatment. The fish oil (Omega Protein, Hammond, LA) contained 10.6% eicosapentaenoic acid and 8% docosahexaenoic acid. Each horse received timothy hay and a textured concentrate at a rate necessary to meet its energy needs. The supplemental oil was top-dressed on the concentrate daily at a rate of 324 mg/kg BW. Horses received their assigned diet for 63 d, during which time they were exercised 5 d/wk in a round pen or on a treadmill. During wk 1, horses exercised for 10 min at a trot. After wk 1, exercise time and intensity were increased so that at wk 5, exercise time in the round pen increased to 30 min (10 min of cantering and 20 min of trotting) per day. Starting at wk 6, horses were exercised 3 d/wk in the round pen for 30 min and 2 d/wk on a treadmill for 20 min. After 63 d, all horses performed an exercise test consisting of a 5-min warm-up at 1.9 m/s, 0% grade, followed by a step test on a 10% grade at incremental speeds of 2 to 8 m/s. Blood samples were taken throughout exercise. During exercise, horses receiving fish oil had a lower heart rate (treatment x time interaction; P < 0.05) and tended to have lower packed cell volume (treatment effect; P = 0.087). Plasma lactate concentrations were not affected by treatment. Plasma glucose concentrations were not different between groups during exercise but were lower (treatment x time interaction; P < 0.01) for the fish oil group during recovery. Serum insulin tended to be lower in fish oil horses throughout exercise (treatment effect; P = 0.064). There was a tendency for glucose:insulin ratios to be higher for fish oil-treated horses throughout exercise (treatment effect; P = 0.065). Plasma FFA were lower (treatment x time interaction; P < 0.01) in horses receiving fish oil than in horses receiving corn oil during the initial stages of the exercise test. Serum glycerol concentrations also were lower in fish oil-treated horses (P < 0.05). Serum cholesterol concentrations were lower in horses receiving fish oil (treatment effect; P < 0.05), but serum triglycerides were not affected by treatment (P = 0.55). These data suggest that addition of fish oil to the diet alters exercise metabolism in conditioned horses.

Animal Feed↗
PubMed1989

Effects of fish meals on rumen bacterial fermentation in continuous culture.

Effects of various forms of fish meal on microbial metabolism were investigated in continuous cultures of rumen contents. Five diets were formulated to contain 12% ruminally degradable protein and 47 to 48% nonstructural carbohydrate. Soybean meal was the major protein source in the control diet, whereas in the other four diets, various fish meals were substituted for 6% of total diet DM. Fish meals were: fish meal containing 34.4% FFA, fish meal containing 34.4% FFA with CaCl2 added, fish meal containing 65.6% FFA, and fish meal defatted using 1:1 ethanol:ether extraction. The five treatments were fermented with pH either held constant at 6.2 or not controlled. When pH was maintained at 6.2, the inclusion of any fish meal except defatted fish meal reduced the acetate:propionate ratio, decreased protein digestion, and reduced microbial N produced/per kilogram DM digested when compared with the soybean control. When not controlled, pH decreased after feeding to 6.0 or lower. Under these conditions, the soybean control had a lower acetate:propionate ratio and lower NDF digestion than all diets containing fish meal. In this study, oil-containing fish meal affected microbial metabolism more negatively when the fermentation pH was held at 6.2 than when the pH was 6.0 or lower.

Animal Feed↗
PubMed2002

Does size really matter? Effects of fish surface area on the settlement and initial survival of Lepeophtheirus salmonis, an ectoparasite of Atlantic salmon Salmo salar.

The effect of the size of the surface area of a fish host on settlement and initial survival of Lepeophtheirus salmonis (Krøyer, 1837) was determined. Atlantic salmon Salmo salar L. of various sizes-small (43 +/- 4 g), medium (173 +/- 32 g) and large (644 +/- 62 g)-were initially examined to ascertain their respective body surface area, excluding gill surface. The initial examination showed a size-dependent body to fin area ratio, with the fin area of small fish representing 34% of the total body area and the fin area of medium and large fish representing 26 and 23%, respectively. Regression analysis of the body weight and standard length against total body surface area gave a good correlation and high R2 values. Two simultaneous experimental infections with approximately 7,000 copepodids of L. salmonis were carried out on fish populations of mixed sizes consisting of 30 small fish, 10 medium-sized fish and 5 large fish, with an approximate total surface area per size group of 2700 cm2. Higher numbers of parasites were found on the small size group, which also had the highest parasite density, with 0.25 and 0.45 parasites cm(-2). Comparison of samples of 5 fish per experimental group revealed that the larger fish had the highest mean numbers of parasites, but the smaller fish still retained the highest density. There was a statistically significantly higher settlement on the fins than on the remainder of the body surface in all size groups. Highest numbers of parasites were particularly found on the dorsal and pectoral fins. Examination of the surface surface area revealed that the dorsal fin had the greater parasite density, with >2 parasites cm(-2) in all fish size groups. These data provide insight into the effects of the amount of host surface area available on parasite settlement and survival, and highlight the potentially increased susceptibility of farmed salmon smolts to infection of this ectoparasite.

Animals↗
PubMed2006

Fish meal in animal feed and human exposure to persistent bioaccumulative and toxic substances.

Persistent and bioaccumulative toxic substances (PBTSs) that end up in fish are health hazards and the object of fish-consumption advisories. Some of these substances are present as extraneous contaminants, e.g., man-made lipophilic pollutants such as organohalogen pollutants, and others such as monomethyl mercury can be considered naturally occurring. Omnivores (e.g., poultry and swine) and especially ruminants that are fed contaminated fish meal can pass monomethyl mercury and organohalogen pollutants to eggs, meat, and dairy products. Differences in fish meal PBTS profiles and farm animal (e.g., poultry, swine, cattle, and farmed fish) physiology modulate PBTSs in animal products. Fish-consumption advisories issued to protect human health do not extend to fish by-products fed to farmed animals. Animals (especially farmed fish) that are fed fish meal can bioconcentrate monomethyl mercury in protein matrices, and organohalogen pollutants can be passed on in the fat components of derived foods. Policies to decrease exposure to monomethyl mercury and organohalogen pollutants must consider farming practices that use fish by-products. A risk assessment of toxic contaminants in fish meal may indicate that food safety objectives must consider the human health impact of foods derived from animals fed contaminated meal.

Animal Feed↗
PubMed2000

[A historical review and some comments on the nuclear transplantation in fish].

In this review article, a brief history and main results of the studies on the nuclear transplantation (cloning) in fish was introduced. Late Professor T. C. Tung (TONG Di-Zhou), a noted Chinese Experimental Embryologist and his research group at the Institute of Zoology, the Chinese Academy of Sciences (CAS) in Beijing, China initiated and established successful technology of nuclear transplantation in fish in 1963. During the past 36 years, most of the studies on fish cloning were performed mainly by Chinese groups except only one article was published by authors in former USSR (Gasaryan et al. 1979), and the other one was published by Japanese authors in Japan (Niwa et al. 1999). The primary goals of the studies of Tung's group were: (1) to study the inter-relationship between the nucleus and the cytoplasm in terms of the controlling effects determined by nucleus or cytoplasm or both during the ontogenesis, cell differentiation and phenotypic expression in a developing animal; and (2) to produce fish clones of commercial importance for agricultural purposes. The most successful results that have been obtained by Tung's group in collaboration with the investigators at various fisheries institutions in China were the production of nucleocytoplasmic adult hybrid fish between different varieties, species, genera and subfamilies that produced viable offspring. Furthermore, these nucleocytoplasmic fish hybrid revealed that while most phenotypic characteristics are controlled by the nucleus, a few are controlled by the cytoplasm or by both. In addition, the resulting nucleocytoplasmic fish hybrids also showed some better characteristics of economic importance such as faster growth rate, increasing of protein content and reducing of fat content in muscle, etc. So far, no such kinds of evidences are available either in amphibian or in mammals. Another most important result obtained by other Chinese groups showed that the uncultured or cultured adult somatic cell in fish which can support the nuclear transplanted eggs developing into adults. They were: (1) a 17 month old gold-fish obtained by transplanting an adult erythrocytes into an enucleated egg (WU et al. 1982); (2) a subcultured kidney cell nucleus of Crucian carp (Carassius auratus) can support the transplanted enucleated egg of same species developing into a three years old adult with female sexual characteristics (CHEN et al. 1986) and (3) a cultured liver cell nucleus from grass carp (Ctenopharyngoden idellus) can support a nuclear transplanted unfertilized egg of the same species developing into an adult fish at least of one year old when that paper was published. Some discussions and comments for evaluating the results obtained from previous studies and suggestions for further investigations in this research field are also provided. More detailed information could be found in the book--"Cloning in Fish-nucleocytoplasmic Hybrids" which was written by Shaoyi Yan in English and published by International Union of Biological Sciences and Educational and Cultural Press Ltd. Hong Kong in 1998.

Animals↗
PubMed1992

[Historical review of insulin and its preparations in pharmacopoeia (3). Fish insulins].

Existence of encapsulated glands situated in the mesentery of certain teleosti was reported by Brockmann (1846) and Stannius (1848), respectively. Thus the gland was named stannius corpuscle or Brockmann body. Later, as results of histological study, cells of stannius corpuscle tissues were constituted with Langerhans islet cells observed in mammalian pancreas by Diammare (1899) and Laguesse (1906). Thus, before the days of discovery of insulin by Banting and Best in 1921, stannius corpuscle has been interesting from the aspects of comparative anatomy and physiology. Rennie (1906) examined a large number of specimens in various species of teleosti and gave the term "principal islet" to easily recognizable stannius corpuscle. Osawa studied comparative anatomy in Freiburg and returned to Tokyo. He continued the study of comparative anatomy of Langerhans islet aand published a report on observation of "principal islet" of flatfish, limanda yokohamae Gth. in 1912 in Japanese. His report seemed to be a milestone of studies of fish insulin in Japan. Macleod attempted to demonstrate direct evidence on secretion of insulin from Langerhans islet cells. Experiments were made on extraction of "principal islet" of teleosti, angler Lophius) and sculpin (Myoxocephalus) to obtain insulin and demonstrated activity. No insulin activity was obtained from pancreatic tissues constituted with acinar cells of these fishes. In the case of elasmobranch, Langerhans islets are not separated, but potent insulin could be extracted from the pancreas. His report published in 1922 was the first report on fish insulin. Succeeding to Macleod's report, several reports on fish insulin were contnributed from Canada, England and U.S.A. until 1929. Dr. Kkumagai, Professor of Internal Medicine, Tohoku Imperial University (Sendai) also conducted the studies on extraction of active principle of pancreas since 1920, independently. But, a Toronto group reached the goal on discovery of insulin earlier than the Sendai group. The Sendai group also described extraction of active principle from the "principal islet" of teleosti. Especially, Ukai (1926) described morphological study on pancreas and stannius corpuscle for more than twenty species of fish. His report played an important role as the next milestone on the road of fish insulin development studies in Japan. In 1926, Dr. Sakaguchi who was a leading clinical diabetologist in Japan published a monograph entitled "Insulin" written in Japanese. He referred the report on fish insulins of McCormick and Noble and Dr. Kumagai's report, however, he commented that production of insulin from fish seemed to be less worthy due to requirements of laborious work to collect small stannius corpuscle from fish. Professor A. Ogata described a textbook entitled "Zoki-Yakuhin-Kagaku (chemistry of organotherapeutics): in 1931. In the first edition, papers of Macleod, McCormick, Dudley and Osawa were referred. In the revised fifth edition (1940) contained description of unpublished data of insulin content of various kinds of fish caught in Japan and supplied from his student Nagasawa. Under the circumstance of expanding tendency of the China Incident to World War II, shortage of importation and production of insulin preparations manufactured from domestic animals was anticipated. Development on manufacture of fish insulin became urgent. [Truncated]

Animals↗
PubMedDate not supplied

[Parasite communities and a fish spawn].

High values of dominance index, low values of evenness and Shannon index are characteristic of component parasite communities of prespawning (Prosopium cylindraceum) and spawn migratory fishes (Coregonus autumnalis, Oncorhynchus nerka). Autogenic specialists are dominant in the component parasite communities of C. autumnalis. The component parasite communities of P. cylindraceum and O. nerka are dominant in a content of generalist species. The O. nerka parasite communities are communities "sentenced to death". Low values of dominance index, high values of evenness abd Shannon index are peculiar to component parasite communities of prespawning and spawning cyprinid fishes (Phoxinus phoxinus, Oreoleuciscus humilis). Autogenic specialists are dominant. Increase of dominance index and decrease of two other indexes characterize the postspawning period. The same tendency characterises infracommunities. Thus, the component parasite communities respond differently to the fish spawn of the cyprinid and coregonid/salmonid fishes. Similarity is in the dominance of autogenic specialists in one case only (C. autumnalis). These differences are defined by the mode of fish stock formation for spawn. The cyprinids congregate for spawning and move apart for foraging and vice versa is observed in the coregonids and salmonids. Autogenic specialists dominance seems to be the important adaptation to reduce a negative effect to host during spawning. Bush and Kennedy in 1994 established that "parasites live in patches (host individuals) and fragments (host populations)". They consider the host fragmentation as "hedging your bets against extinction" due to frequency and magnitude anthropogenic factors, which increase fragmenting of host populations. This conclusion was made for a species level. From the other hand the fragmentation is a natural feature for a single host population too. Such fragmentation is a host population structure. The role of fragmentation is obvious from the data on component parasite communities during fish spawn. The fragmentation decreases in the cyprinids and increases in the salmonids that leads to the growing of the cyprinid component parasite communities diversity and to declining the salmonid component parasite communities diversity. Nevertheless the role of host population structure in a component parsite community structure is not obvious, because parasites are able or not able to "recognise" different host subpopulation groups. It is well known from data on parasite species population biology. Such recognizable subpopulation groups or groups can be a "real fragment" for the parasite community. The question is what parameters could be used for this purpose on a component community level. Host population age structure can be used as an example, because the age groups are one of the invariable population characters. Value of Shannon index for component parasite communities of spawn migratory O. nerka (5+) is similar to that of fishes of 1+ age. Difference is statistically insignificant. It is insignificant between the parasite communities of 2+ and 3+ age groups too. Fishes of these two groups could be defined as a real united fragment. It spite of similarity between the fishes of 5+ age group and fish of 1+ age group they are not united fragment. The parasite community of 1+ age fishes is not stabilized yet and one of 5+ age is a community "sentenced to death". Thus the structuring of O. nerka freshwater parasite communities are defined by 3 real host age fragments: 1+ age group, 2 and 3+ age group, 4+ age group. It looks as that Shannon index is suitable parameter to study a parasite communities structure.

Age Factors↗
PubMed2002

Level and extent of mercury contamination in Oregon, USA, lotic fish.

We conducted a probability survey of 154 Oregon, USA, stream and river sites to assess the spatial extent of mercury (Hg) contamination in fish tissue. Samples consisted of whole-fish analyses of both small (<120 mm) and large (>120 mm) fish at each site, when both were present. Overall, Hg levels (microgram/g) in small fish (mean = 0.031; standard deviation [SD] = 0.029), large piscivores (mean = 0.284; SD = 0.175), and large invertivores (mean = 0.055; SD = 0.047) were found within fairly narrow ranges; always above detection (0.0025 microgram/g) and almost always below 0.4 microgram/g. Given the great ecoregion diversity across Oregon, the narrow range in fish tissue Hg levels suggests that atmospheric transport is an important vehicle for Hg distribution. In small fish, Hg levels were almost always low and showed little meaningful difference among fish taxa. In large fish, Hg levels were significantly related to fish length. Piscivores (pikeminnow and bass) had significantly higher Hg levels, and the slope of their Hg level/length relationship was much steeper than for invertivores. Salmonids, the most commonly occurring fish taxon in Oregon, exceeded 0.1 microgram Hg/g (deemed protective for fish-eating mammals) in an inferred 15% of stream lengths where they occurred. Pikeminnows and bass were found at fewer sites, but they exceeded 0.1 microgram Hg/g in an inferred 96 and 70%, respectively, of stream lengths where they occurred.

Animals↗
PubMed2004

[Safety evaluation of food from transgenic fish and the molecular biological mechanism].

More progresses have been made in the studying of transgenic fish in China, but the studying work of safety evaluation of food from transgenic fish are started up just now. Compared to plants and animals on the land, it is more difficult to control the mobility of fish and fish can give birth to a large number of offsprings, so the ecological risk or hazard about transgenic fish is more critical than others. Another safety problem is the chimerism which is initiated by the gene transfer methods used in the transgenic fish. Getting sterile triploid transgenic fish and fixed point integration are efficient to solve the two problems above respectively. The solution of the two problems are also the basis of safety evaluation and detection of food from transgenic fish. Up to now, there are little reports on the safety evaluation of transgenic fish including nutritional evaluation and allergic reaction, and there are no basic research on the detection of transgenic fish for the aim of food safety. In brief, it is very urgent to start up the research on the safety evaluation and detection of transgenic fish for the control of food safety.

Animals↗
PubMed1989

[Chlorinated pesticide residues and polychlorinated biphenyls in fish from various locations in Czechoslovakia].

Samples of 14 fishes (175 samples on the whole) were examined in 1984 to 1986 for residues of chlorinated pesticides and polychlorinated biphenyls. Residues of the given substances were present in all the samples. The contents of chlorinated pesticide residues in fish are influenced mainly by the food spectrum; significant influence was also exerted by the contamination of the environment where the fish lived, by the age of the fish, and by the amount of their body fat in which the lipophile chlorinated carbohydrates are stored. No tolerance limits have been proposed in Czechoslovakia for the residues of chlorinated carbohydrates in fish bodies, except for the sum of DDT = 2.00 mg per kg of fat. When the data on the fish samples were compared with the highest admissible content of chlorinated pesticides per unit mass of fish muscle tissue tolerated in the FRG and the content of PCB tolerated in the USA, the fish from the Vltava river downstream of Prague fail to comply with these FRG and US regulations; all fish from all other places comply with them. Owing to large differences in the contents of fat in muscle between different fishes, it is more conclusive from the point of view of food hygiene to express the results as data per 1 kg of muscular tissue; these data represent real contents in fish as foodstuff.

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