Various Types Of Fish Research Articles

Abstract MP002: Dietary Intake of Marine Omega-3 Fatty Acids is Directly Associated with Coronary Flow Reserve among Male Middle-Aged Twins

Introduction: Evidence from previous studies suggests that dietary marine omega-3 fatty acids have cardioprotective properties. However, our understanding of the mechanism for these beneficial effects remains limited. We sought to examine the association between marine omega-3 fatty acid intake and coronary flow reserve (CFR), a measure of overall coronary vasodilator capacity and microvascular function. Hypothesis: Increased dietary intake of marine omega-3 fatty acids is associated with higher CFR. Methods: A sample of 259 male middle-aged twins, including 115 monozygotic and dizygotic twin pairs and 29 unpaired twins, with no previous history of coronary heart disease (CHD), was recruited from the Vietnam Era Twin Registry. Prior to the study visit, all twins completed a 3-day food record detailing their diet for the previous three days. Dietary information was analyzed using specialized nutrition software and reported intakes of various types of fish were used to derive marine omega-3 fatty acid (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) intake. CFR was measured using positron emission tomography [N 13 ] ammonia with quantitation of myocardial blood flow at rest and after adenosine stress. Mixed-effect regression analysis was used to assess the association between marine omega-3 fatty acid intake and CFR both at the individual level and within twin pairs. Potential confounders included demographic characteristics, lifestyle factors (including physical activity), traditional cardiovascular disease (CVD) risk factors, use of omega-3 and multivitamin supplements, total energy intake, and other nutritional factors such as intake of cholesterol, sodium, alcohol, sugar-sweetened beverages, and saturated and monounsaturated fatty acids. Results: The twins’ mean age was 54 years (SD = 3.0) and 93.1% (241 out of 259) were white. An increase in dietary intake of marine omega-3 fatty acids of 1 g/d was associated with a 7.6% higher CFR (95% CI: 0.6, 15.2) after adjustment for potential confounders ( P = 0.033). This association also persisted within twin pairs: a 1 g/d within-pair difference in dietary intake of marine omega-3 fatty acids was associated with a 16.3% higher CFR in the twin with the greater dietary intake of marine omega-3 fatty acids than in the co-twin with the lower dietary intake ( P = 0.020). These associations did not differ by zygosity. Conclusions: Dietary intake of marine omega-3 fatty acids is directly associated with CFR, a measure of coronary microvascular function, independent of traditional CVD risk factors and shared familial and genetic factors. Our study suggests a potential novel mechanism for the protective effects of dietary marine omega-3 fatty acids on the cardiovascular system and supports the benefit of consuming marine omega-3 fatty acids to promote cardiovascular health.

Methyl mercury exposure in Swedish women with high fish consumption

We studied the exposure to methyl mercury (MeHg) in 127 Swedish women of childbearing age with high consumption of various types of fish, using total mercury (T-Hg) in hair and MeHg in blood as biomarkers. Fish consumption was assessed using a food frequency questionnaire (FFQ), including detailed information about consumption of different fish species, reflecting average intake during 1 year. We also determined inorganic mercury (I-Hg) in blood, and selenium (Se) in serum. The average total fish consumption, as reported in the food frequency questionnaire, was approximately 4 times/week (range 1.6–19 times/week). Fish species potentially high in MeHg, included in the Swedish dietary advisories, was consumed by 79% of the women. About 10% consumed such species more than once a week, i.e., more than what is recommended. Other fish species potentially high in MeHg, not included in the Swedish dietary advisories, was consumed by 54% of the women. Eleven percent never consumed fish species potentially high in MeHg. T-Hg in hair (median 0.70 mg/kg; range 0.08–6.6 mg/kg) was associated with MeHg in blood (median 1.7 μg/L; range 0.30–14 μg/L; r s=0.78; p<0.001). Hair T-Hg, blood MeHg and serum Se (median 70 μg/L; range 46–154 μg/L) increased with increasing total fish consumption ( r s=0.32; p<0.001, r s=0.37; p<0.001 and r s=0.35; p=0.002, respectively). I-Hg in blood (median 0.24 μg/L; range 0.01–1.6 μg/L) increased with increasing number of dental amalgam fillings. We found no statistical significant associations between the various mercury species measured and the Se concentration in serum. Hair mercury levels exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 μg MeHg/kg b.w. per day in 20% of the women. Thus, there seems to be no margin of safety for neurodevelopmental effects in fetus, for women with high fish consumption unless they decrease their intake of certain fish species.

Analysis of demand for fish in Bangladesh

An analysis of fish consumption patterns, and how they are likely to change as income and relative price changes, is required to assess the welfare impact of technological and policy changes in the fisheries and aquaculture sectors. This analysis is based on a matrix of price and income elasticities of demand for fish by type, as fish is a heterogeneous product and consumption patterns may differ by type of product. This paper presents estimates of fish demand elasticities by fish type for Bangladesh, using individual household expenditure data (5,667 households) collected by the Bangladesh Bureau of Statistics in 1988/89. It uses a multistage budgeting framework that estimates a demand function for food in the first stage, a demand function for fish (as a group) in the second stage and a set of demand functions for fish by type in the third stage. Estimated demand elasticities vary across fish type and across income class. Among the various types of fish, carp have the highest (in absolute terms) own‐price elasticity. Income elasticities of all fish types consistently fall with the increase in per capita expenditure level of households, but none of the fish types become an inferior good at the highest income quartile. Dried fish has the lowest income elasticities for the richest quartile of the population.

Relative catch ability and performance of three strains of rainbow trout, Salmo gairdneri Richardson, in a small fishery

Abstract. The performances of two strains of rainbow trout, Salmo gairdneri Richardson, and a hybrid were assessed in a put-and-take fishery against stock from the normal supplier. The three batches of experimental fish were reared to the size usually stocked in the fishery and they and two batches of the normal stock fish were given distinctive dye-marks using a Panjet inoculator. Anglers’ returns were analysed and demonstrated that there were significant differences in the catchability of the various types of fish throughout the trial period. There was no apparent difference between strains in their susceptibility to the fly-fishing methods employed, nor between their growth rates whilst in the fishery, despite the clear superiority of some genotypes under fish-farm conditions. These factors are discussed in relation to the management of put-and-take trout fisheries.

Yield to Anglers of Spring and Autumn Stocked, Hatchery Reared and Wild, Brown Trout (Salmo trutta L.)

SUMMARY Tagging experiments are described where hatchery over-yearlings and similar sized wild brown trout were spring-stocked in two small angling lakes. This was followed in the autumn with a stocking of hatchery fingerlings and wild fish. The spring-stocked hatchery fish gave the best return to anglers of 9.3% over the first two seasons, while the autumn-stocked hatchery fish apparently suffered heavy over-winter mortality — giving a return of only 1.3% over a comparable time period. Wild fish gave low return rates of 2.9 and 2.0% from spring and autumn stockings respectively, although netting exercises indicated that these survived longer in the lake than hatchery fish. Analysis of the methods of capture indicated that hatchery fish were more liable to be caught by bait fishing whereas fly fishing was the most successful for wild fish. Estimates were made of the relative cost effectiveness of the various types of fish in terms of returns to the angler.