Search USGS⌕ Search

SEARCH · Search USGS

Results for “Journal of Nutrition”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
USGS2014

An assessment of morphometric indices, blood chemistry variables and an energy meter as indicators of the whole body lipid content in Micropterus dolomieu , Sander vitreus and Ictalurus punctatus

The effectiveness of several non-lethal techniques as indicators of total lipid content in smallmouth bass Micropterus dolomieu , walleye Sander vitreus and channel catfish Ictalurus punctatus was investigated. The techniques included (1) the Fulton and relative condition factors, (2) relative mass, (3) plasma indicators of nutritional status (alkaline phosphatase, calcium, cholesterol, protein, triglycerides and glucose) and (4) readings from a hand-held, microwave energy meter. Although simple linear regression analysis showed that lipid content was significantly correlated with several predictor variables in each species, the r 2 values for the relations ranged from 0·17 to 0·50 and no single approach was consistent for all species. Only one model, between energy-meter readings and lipid content in I. punctatus , had an r 2 value (0·83) high enough to justify using it as a predictive tool. Results indicate that no single variable was an accurate and reliable indicator of whole body lipid content in these fishes, except the energy meter for I. punctatus .

Journal of Fish Biology↗
USGS1980

Food use and nutrition of black ducks nesting in Maine

Based on 32 adult black ducks ( Anas rubripes ) collected during the nesting seasons of 1974-76, the proportion of macro invertebrates (as aggregate [average] percent of dry weight) in the diet of males, egg-laying females, and postlaying females was 60, 75, and 55%, respectivey. Sample sizes were small, and the differences associated with sex and reproductive condition were not signficant. Molluscs, Isopods, ephemeropteran and odonate nymphs, and coleopteran, trichopteran, and dipteran larvae contributed 74% of the dry weight and 64% of the gross energy ingested. Data from proximate analyses of 9 invertebrate and 9 plant foods were combined with food habits data to estimate the nutrients available to breeding hens. We concluded that females with access to an adequate amount of natural food including invertebrates and the seeds and tubers of aquatic plants would obtain sufficient minerals, protein, and energy for reproduction. Food quality does not appear to limit the density of black ducks nesting in Maine.

Maine↗
USGS2000

Evaluating immunocontraception for managing suburban white-tailed deer in Irondequoit, New York

Immunocontraception is frequently proposed as an alternative to lethal removal of females for deer management. However, little information is available for evaluating the potential of applying immunocontraceptives to free-ranging populations. Our objectives were to estimate effort required to apply porcine zona pellucida (PZP) to individual deer and assess the utility of using immunocontraception to control growth of deer populations. The study was conducted in a 43-km2 suburban community with about 400 deer. Effort per deer was measured as time required to capture and mark deer, and then to apply booster immunocontraceptive treatments by remote injection. Estimates of numbers of females to treat to control population growth were based on the generalized sustained-yield (SY) model adapted for contraception of females. The SY curve was calibrated using data on deer abundance acquired from aerial population surveys and nutritional condition of females removed by a concurrent culling program. Effort was influenced by 4 factors: deer population density, approachability of individual deer, access to private and public land, and efficacy of the contraceptive treatment. Effort and deer density were inversely related. Cumulative effort for treatment increased exponentially because some deer were more difficult to approach than others. Potential of using immunocontraception at low deer population densities (<25% ecological carrying capacity) is limited by the interaction of the proportion of breeding-age females in the population and treatment efficacy, as well as encounter rates. Immunocontraception has the best potential for holding suburban deer populations between 30 and 70% of ecological carrying capacity, but is likely to be useful only in localized populations when the number of females to be treated is small (e.g., <200 deer).

New York↗
USGS2003

Clinical pathology and assessment of pathogen exposure in southern and Alaskan sea otters

The southern sea otter ( Enhydra lutris nereis ) population in California (USA) and the Alaskan sea otter ( E. lutris kenyoni ) population in the Aleutian Islands (USA) chain have recently declined. In order to evaluate disease as a contributing factor to the declines, health assessments of these two sea otter populations were conducted by evaluating hematologic and/or serum biochemical values and exposure to six marine and terrestrial pathogens using blood collected during ongoing studies from 1995 through 2000. Samples from 72 free-ranging Alaskan, 78 free-ranging southern, and (for pathogen exposure only) 41 debilitated southern sea otters in rehabilitation facilities were evaluated and compared to investigate regional differences. Serum chemistry and hematology values did not indicate a specific disease process as a cause for the declines. Statistically significant differences were found between free-ranging adult southern and Alaskan population mean serum levels of creatinine kinase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, calcium, cholesterol, creatinine, glucose, phosphorous, total bilirubin, blood urea nitrogen, and sodium. These were likely due to varying parasite loads, contaminant exposures, and physiologic or nutrition statuses. No free-ranging sea otters had signs of disease at capture, and prevalences of exposure to calicivirus, Brucella spp., and Leptospira spp. were low. The high prevalence (35%) of antibodies to Toxoplasma gondii in free-ranging southern sea otters, lack of antibodies to this parasite in Alaskan sea otters, and the pathogen's propensity to cause mortality in southern sea otters suggests that this parasite may be important to sea otter population dynamics in California but not in Alaska. The evidence for exposure to pathogens of public health importance (e.g., Leptospira spp., T. gondii ) in the southern sea otter population, and the naïveté of both populations to other pathogens (e.g., morbillivirus and Coccidiodes immitis ) may have important implications for their management and recovery.

Journal of Wildlife Diseases↗
USGS1961

Chemotherapy of hexamitiasis in fish

Heramita salmonis , the causative agent of hexamitiasis in salmonoid fishes, is endemic in most trout and salmon hatcheries throughout North America. The etiologic agent, a protozoan flagellate, ostensibly causes cellular damage in the caecal mucosa of afflicted fishes. It is also believed that heavy infections may interfere with normal growth by direct competition with the host for available nutrients in the intestinal tract. While the role of this supposed pathogen is relatively unclear, its presence in test fishes at this laboratory has caused considerable concern during the conduct of controlled nutritional studies. Although McNeil et al (1941) showed that the incidence of Hexamita infections is widespread, hexamitiasis appears to be commercially important only in turkeys (Almquist and Johnson, 1951) and fish (Davis, 1953). Very little has been reported on the protozoacidal effects of various drugs on the Hexamita infections in fish (Fish and McKernan, 1940; Smith and Quistorff, 1940; and Nelson, 1941). The most widely used chemotherapeutic agents are p-carbamidobenzene arsonic acid (carbarsone) and mild mercurous chloride (calomel). Initial attempts at this laboratory to control the parasite in infected fish populations using these two drugs at the recommended concentrations demonstrated that the former was erratic in effectiveness and the latter was toxic and produced loss in fish weight. The present study, therefore, was undertaken to find more effective therapeutic agents which would be palatable, non-toxic, and still effectively eradicate the protozoan from fish.

Journal of Parasitology↗
USGS1985

Nutritional ecology of a fossorial herbivore: protein N and energy value of winter caches made by the northern pocket gopher, Thomomys talpoides

Northern pocket gophers ( Thomomys talpoides ) are fossorial herbivores that excavate belowground plant parts for food. In subalpine areas during autumn and winter, pocket gophers hoard plant parts in caches placed in or under snow. We examined the size and composition of 17 nival caches and tested the hypotheses that (i) cached food can provide complete energy and protein N sustenance during typical periods when burrowing is precluded by soil conditions, and (ii) cached food is a random sample of items encountered by burrowing gophers during tunnel excavation. Our data indicate that caches provide substantially more energy than protein in terms of a pocket gopher's daily maintenance requirements. Nevertheless, quantities stored are sufficient to allow individuals to endure commonly encountered adverse environmental conditions without entering negative energy or protein balance. Analysis of stomach contents and a comparison of cache composition to availability of plant species suggests that gophers consume high-protein items as they are encountered, and store low-protein items in caches.

Canadian Journal of Zoology↗
USGS1988

Pyrite formation in the Lower Cretaceous Mowry Shale: Effect of organic matter type and reactive iron content

Geochemical analysis of the Lower Cretaceous Mowry Shale in Wyoming and Montana shows that organic matter type and reactive iron content limited pyrite formation during early diagenesis. Consequently, direct interpretation of paleosalinity cannot be made from a carbon/sulfur plot. Mowry Shale samples with hydrogen index (HI) less than 150 (mg hydrocarbon/ organic carbon) contain low amounts of sulfur. In these samples, bacterial reduction of sulfate may have been inhabited by low nutritive content of the organic matter. For Mowry samples with HI greater than 150 there is a range of sulfur values and a positive correlation between iron and sulfur. The iron sulfur regression is approximately parallel to the stoichiometric pyrite line and intersects the iron axis at 0.5 percent. On average, 60 percent of the iron present was nonreactive; the remaining iron reacted with sulfide to form pyrite. For samples with HI greater than 150, pyrite formation was limited by sulfide or organic carbon content but by reactive iron content. In one modern setting, where salinity is greater than one-half normal seawater, sulfate content does not limit pyrite formation (Berner and Raiswell, 1984). From this analysis then, it can be estimated that the Mowry Sea was not a fresh water body but was either of normal marine salinity or contained brackish water with greater than one-half normal salinity.

Wyoming↗
USGS2004

Dynamics of intertidal foraging by coastal brown bears in Southwestern Alaska

Shoreline areas provide early season foraging opportunities for coastal bears in Alaska. We investigated use by brown bears (Ursus arctos) of soft-shelled (Mya arenaria) and Pacific razor (Siliqua patula) clams at Katmai National Park, Alaska, USA, to identify the potential importance of these clams to bears. We used direct observations of bear foraging behavior in the summers of 1998, 1999, and 2001 to model the nutritional importance of clamming behavior. We also used previously described models to estimate the relative importance of clamming and vegetative foraging in meeting the maintenance requirements of bears. At the harvest rate that we observed (0.69 ?? 0.46 clams/min), bears achieved higher rates of digestible energy intake than those foraging on vegetation. Although clams are available for only a few hours per day, bears could significantly reduce their total daily foraging time by utilizing clams. Smaller single bears and females with dependent young were the most represented groups of bears using intertidal areas. Large male bears, faced with higher energy requirements, likely are unable to efficiently exploit these intertidal resources. Depending on the relationship between clam size and tissue mass, the relative quality of clams differed by species. Bears foraging on Pacific razor clams required the fewest hours to meet maintenance, followed by bears consuming soft-shelled clams. Our findings highlight the significance of intertidal habitats for coastal bears, especially females.

Journal of Wildlife Management↗
USGS1975

Some nutritional aspects of reproduction in prairie nesting pintails

The nutritional significance of invertebrate foods in the diet of breeding hen waterfowl during the period of egg formation is discussed. Proximate, elemental, and amino acid analyses of the principal foods consumed by hen pintails ( Anas acut ) during the nesting season indicate the animal foods selected are rich sources of protein and calcium, whereas plant foods tested were low in protein, particularly in the essential amino acids lysine and methionine. Calcium content in major plant foods was far below needs considered adequate for egg production. Studies with penned, hand-reared pintails indicated the inadequacy of wheat as the dietary staple during breeding. Egg production among pairs on the control diet differed significantly from that of the wheat plus oystershell (P < 0.05) and wheat (P < 0.01) diets. Pairs fed wheat during the breeding period experienced nearly complete reproductive failure. The poor reproductive response among hens on the diet of wheat plus oystershell suggested that calcium availability was not the only factor limiting productivity.

Journal of Wildlife Management↗
USGS1998

Timing and synchrony of parturition in Alaska caribou

Timing of parturition of caribou ( Rangifer tarandus ) varies within populations, but the relative influences of nutritional condition of females during the autumn breeding season and during gestation on that variation is not known. We determined timing of parturition of caribou in Denali National Park, Alaska, during 1984–1995, which had wide variation in snowfall that influenced nutritional condition and productivity of females. The first young were observed each year between 4 and 15 May. Annual median dates of parturition for radiocollared females during 1987–1995 varied from 13 to 21 May. Synchrony of births (i.e., proportion of births during 7 days centered on the median date) did not vary significantly among years ( P > 0.05). Females ≤4 years old were more likely to give birth after the annual median date than older females ( P = 0.005). Dates of parturition were significantly correlated with masses of females in the previous autumn ( P = 0.034) but not in late winter ( P = 0.155). Births tended to be earlier for parous females that were not lactating during the previous breeding season compared to those that were lactating ( P = 0.030). Annual onsets of parturition varied significantly with snowfall in late winter prior to conception ( P = 0.012) but not with snowfall during gestation. Timing of parturition in our study appeared to be a function of physical condition of breeding females in autumn.

Journal of Mammalogy↗
USGS1995

Screening tests for assessing the anaerobic biodegradation of pollutant chemicals in subsurface environments

Screening methods were developed to assess the susceptibility of ground water contaminants to anaerobic biodegradation. One method was an extrapolation of a procedure previously used to measure biodegradation activity in dilute sewage sludge. Aquifer solids and ground water with no additional nutritive media were incubated anaerobically in 160-ml serum bottles containing 250 mg·l −1 carbon of the substrate of interest. This method relied on the detection of gas pressure or methane production in substrateamended microcosms relative to background controls. Other screening procedures involved the consumption of stoichiometrically required amounts of sulfate or nitrate from the same type of incubations. Close agreement was obtained between the measured and calculated amounts of substrate bioconversion based on the measured biogas pressure in methanogenic microcosms. Storage of the microcosms for up to 6 months did not adversely influence the onset or rate of benzoic acid mineralization. The lower detection limits of the methanogenic assay were found to be a function of the size of the microcosm headspace, the mean oxidation state of the substrate carbon, and the method used to correct for background temperature fluctuations. Using these simple screening procedures, biodegradation information of regulatory interest could be generated, including, (i) the length of the adaptation period, (ii) the rate of substrate decay and (iii) the completeness of the bioconversion.

Journal of Microbiological Methods↗
USGS2018

Environmental, anthropogenic, and dietary influences on fine-scale movement patterns of Atlantic salmon through challenging waters

Partial barriers to migration can affect migratory fish population dynamics and be influenced by many biotic, abiotic, and anthropogenic factors, including nutritional deficiencies. We investigated how such variables (including a thiamine deficiency) impact fine-scale movement of landlocked Atlantic salmon ( Salmo salar ) by treating returning spawners with thiamine and observing their attempts to climb a human-altered, high velocity stretch of river using fine-scale radio telemetry. Multiple re-entries into a river section, along with water temperature, strongly influenced movement rates. High or increasing discharge encouraged downstream movement; males abandoned migratory attempts at a higher rate than females. Although thiamine-injected salmon exhibited greater migratory duration, this did not produce a measurable improvement in passage performance, possibly due to the difficulty associated with this section of river — among 24 tagged salmon staging 10.9 attempts each and lasting 1.5 days per attempt on average, only three traversed the entire reach. This study provides new insights into how biotic and abiotic variables affect fish movement, while suggesting limits to the potential for human intervention (thiamine injections) to assist passage through partial migratory barriers.

New York, Vermont↗
USGS2022

Evaluating risks associated with capture and handling of mule deer for individual-based, long-term research

Capture and handling techniques for individual-based, long-term research that tracks the life history of animals by recapturing the same individuals for several years has vastly improved study inferences and our understanding of animal ecology. Yet there are corresponding risks to study animals associated with physical trauma or capture myopathy that can occur during or following capture events. Rarely has empirical evidence existed to guide decisions associated with understanding the magnitude of capture-related risks, how to reduce these risks when possible, and implications for mortality censoring and survival estimates. We used data collected from 2,399 capture events of mule deer ( Odocoileus hemionus ) via helicopter net-gunning to compare daily survival probabilities within a 10-week period centered on a capture event and evaluated how animal age, nutritional condition (body fat), and various handling methods influenced survival before, during, and following a capture event. Direct mortality resulting from capture efforts was 1.59%. Mean daily survival was 0.9993 ± 0.0001 (SE) during the 5-week pre-capture window, was depressed the day of capture at 0.9841 ± 0.0004, and rebounded to 0.9990 ± 0.0008 during the 5-week post-capture window. Neither capture nor handling had a detectable effect on post-capture survival, including handling time ( x̄ = 13.30 ± 1.87 min), capture time of year (i.e., Dec or Mar), tooth extraction, and the number of times an animal had been recaptured (2–17 times). Although mortality rate was slightly elevated during capture (resulting from physical trauma associated with capture), age and nutritional condition did not influence the probability of mortality during a capture event. Following a capture event, nutritional condition influenced survival; however, that relationship was consistent with expected effects of nutritional condition on winter survival and independent of capture and handling. Overall survival rates 5 weeks before capture and 5 weeks after capture were not different. A specified window of time with depressed survival following capture and handling was not evident, which contradicts the implementation of a predetermined window often used by researchers and managers for censoring mortalities that occur after capture. Previous notions that censorship of all mortality data in the 2 weeks following capture is unwarranted and risks removal of meaningful data. With previous evidence guiding our protocols for capture (e.g., reduced chase time) and handling (e.g., temperature mitigation), low direct mortality and almost undetectable indirect mortality post capture reinforces the efficacy of helicopter net-gunning for capture and recapture of mule deer in long-term, individual-based studies.

Wyoming↗
USGS2014

Reproductive effects on fecal nitrogen as an index of diet quality: an experimental assessment

Concentration of fecal nitrogen has been used widely as an indicator of dietary quality for free-ranging ruminants. Differences in digestive function between species of dimorphic ungulates render interspecific comparisons of fecal nitrogen unreliable; however, whether intraspecific sexual differences in digestive function also bias this nutritional index is unknown. Our objective was to compare sex-specific variation in concentration of fecal nitrogen using male, nonlactating female, and lactating female white-tailed deer ( Odocoileus virginianus ) on high- and low-quality diets. During weekly trials over spring and summer (2008-2009), we monitored intake rates, collected feces twice daily, and used micro-Kjeldahl procedures to determine percent fecal nitrogen. We also determined nitrogen content of feces following a neutral detergent fiber (NDF) rinse during pre-, peak, and postlactation. Fecal nitrogen reflected general differences in dietary quality between diets; however, fecal nitrogen of lactating females in both dietary groups was lower than for males or nonlactating females throughout lactation. Nitrogen concentration following an NDF rinse also was lower for lactating females during peak lactation. We hypothesize that the remodeling of the digestive tract and increased rumination by lactating females may enhance their ability to extract nitrogen from their forage. These adjustments may expand the foraging options of lactating females by increasing their ability to process low-quality foods, but also affects the interpretation of fecal nitrogen during the season of lactation.

Journal of Mammalogy↗
USGS2002

Relating net nitrogen input in the Mississippi River Basin to nitrate flux in the Lower Mississippi River--A comparison of approaches

A quantitative understanding of the relationship between terrestrial N inputs and riverine N flux can help guide conservation, policy, and adaptive management efforts aimed at preserving or restoring water quality. The objective of this study was to compare recently published approaches for relating terrestrial N inputs to the Mississippi River basin (MRB) with measured nitrate flux in the lower Mississippi River. Nitrogen inputs to and outputs from the MRB (1951 to 1996) were estimated from state-level annual agricultural production statistics and NO y (inorganic oxides of N) deposition estimates for 20 states that comprise 90% of the MRB. A model with water yield and gross N inputs accounted for 85% of the variation in observed annual nitrate flux in the lower Mississippi River, from 1960 to 1998, but tended to underestimate high nitrate flux and overestimate low nitrate flux. A model that used water yield and net anthropogenic nitrogen inputs (NANI) accounted for 95% of the variation in riverine N flux. The NANI approach accounted for N harvested in crops and assumed that crop harvest in excess of the nutritional needs of the humans and livestock in the basin would be exported from the basin. The U.S. White House Committee on Natural Resources and Environment (CENR) developed a more comprehensive N budget that included estimates of ammonia volatilization, denitrification, and exchanges with soil organic matter. The residual N in the CENR budget was weakly and negatively correlated with observed riverine nitrate flux. The CENR estimates of soil N mineralization and immobilization suggested that there were large (2000 kg N ha −1 ) net losses of soil organic N between 1951 and 1996. When the CENR N budget was modified by assuming that soil organic N levels have been relatively constant after 1950, and ammonia volatilization losses are redeposited within the basin, the trend of residual N closely matched temporal variation in NANI and was positively correlated with riverine nitrate flux in the lower Mississippi River. Based on results from applying these three modeling approaches, we conclude that although the NANI approach does not address several processes that influence the N cycle, it appears to focus on the terms that can be estimated with reasonable certainty and that are correlated with riverine N flux.

Journal of Environmental Quality↗
USGS2001

Dietary restriction causes chronic elevation of corticosterone and enhances stress response in red-legged kittiwake chicks

Release of corticosterone in hungry kittiwake chicks facilitates begging and allows them to restore depleted energy reserves by increasing parental food provisioning. However, in order to avoid detrimental effects of chronic elevation of corticosterone, chicks might suppress adrenocortical activity in response to prolonged food shortages. In this study we examined temporal dynamics of corticosterone release in red-legged kittiwake (Rissa brevirostris) chicks exposed to prolonged restrictions in energy content and/or nutritional quality (low versus high lipid content) of their food. Starting at the age of 15 days, chicks were fed either high- or low-lipid fish at 40%, 65%, and 100% of ad libitum energy intake. Body mass measurements and baseline plasma samples were taken on a weekly basis after beginning of the treatment. After 3 weeks of treatment, chicks were exposed to a standardized acute handling and restraint stress protocol, where in addition to a baseline sample, three plasma samples were taken at intervals up to 50 min. We found that food-restricted chicks had lower body mass, chronically (during 2-3 weeks) elevated baseline and higher acute stress-induced levels of corticosterone compared to chicks fed ad libitum. Low lipid content of food further exacerbated these effects. An increase in baseline levels of corticosterone was observed within a week after energy requirements of food-restricted chicks exceeded their daily energy intake. A tendency for suppression of adrenocortical activity was observed in treatments fed low-lipid diets only at the end of the experiment. We suggest that nest-bound chicks, if food-stressed, might suffer deleterious effects of chronic elevation of corticosterone.

Journal of Comparative Physiology B: Biochemical, ↗
USGS2026

Thiaminase I activity is high in grass and silver carp, but negligible in bighead and black carp

Bighead carp ( Hypophthalmichthys nobilis ), black carp ( Mylopharyngodon piceus ), grass carp ( Ctenopharyngodon idella ), and silver carp ( H. molitrix ) have spurred wide concern of potential ecosystem disruption as they threaten to invade the Laurentian Great Lakes. Besides competition for resources, carp may also have disadvantageous nutrition for predators. One biochemical aspect to consider in carp is production of the enzyme thiaminase that cleaves thiamine (vitamin B 1 ), making it unavailable to most vertebrates. The function of thiaminase within prey fishes is unclear, but roughly half of all fishes tested have measurable thiaminase activity. Predators consuming large volumes of prey with high thiaminase activity can develop thiamine deficiency, ultimately leading to offspring mortality. Three invasive carp (black carp, grass carp, and bighead carp) have no published thiaminase data. We tested juvenile (<160 mm standard length) black carp (n = 38), bighead carp (n = 7), grass carp (n = 50), and silver carp (n = 50) for thiaminase activity. All four species had measurable activity; however, grass carp had statistically higher thiaminase activity (p < 0.001; median = 61 nmol/g/min) than the other three species. Silver carp had the second highest thiaminase activity (14 nmol/g/min). Bighead (2.7 nmol/g/min) and black (2.2 nmol/g/min) carp had the lowest thiaminase activity; activities were often near detection limits. Predators with diets heavily composed of grass carp or silver carp may experience thiamine deficiency, though seasonal variation in carp size and other food source availability may determine potential effects of invasive carp predation in Great Lakes food webs.

Journal of Great Lakes Research↗
USGS2009

Egg fatty acid composition from lake trout fed two Lake Michigan prey fish species.

We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife-bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos.

Journal of Aquatic Animal Health↗