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At least 55 records · Page 3Linked to original sources
USGS2005

Naturally occurring secondary nutritional hyperparathyroidism in cattle egrets ( Bubulcus ibis ) from Central Texas

Naturally occurring secondary nutritional hyperparathyroidism is described in the nestlings of two colonies of cattle egrets ( Bubulcus ibis ) from Central Texas (Bryan and San Antonio, Texas, USA). Nestlings from a third colony (Waco, Texas, USA) were collected in a subsequent year for comparison. Birds from the first two colonies consistently had severe osteopenia and associated curving deformities and folding fractures of their long bones. These birds also had reduced bone ash, increased osteoclasia, a marked decrease in osteoblast activity, variable lengthening and shortening of the hypertrophic zone of the epiphyseal cartilage, decreased and disorganized formation of new bone, and a marked hypertrophy and hyperplasia of the parathyroid glands as compared to birds collected from the third colony. Fibrous osteodystrophy was found in all of the birds from San Antonio and Bryan. Evidence of moderate to severe calcium deficiency was also identified in 33% of the cattle egrets collected from Waco. Gut contents of affected chicks contained predominately grasshoppers and crickets; vertebrate prey items were absent from the Bryan birds. Grasshoppers and crickets collected from fields frequented by the adult egrets in 1994 had 0.12–0.28% calcium and 0.76–0.81% phosphorus. Pooled grasshoppers and crickets collected during a subsequent wet early spring averaged 0.24% calcium and 0.65% phosphorus. Although the phosphorus content of the insect prey was adequate for growth, calcium was approximately one-third the minimum calcium requirement needed for growth for other species of birds. It was postulated that cattle egrets breeding in Central Texas have expanded their range into habitat that contains less vertebrate prey, and as a result, many nestling egrets are being fed diets that contain suboptimal calcium. Therefore, in years where vertebrate prey is scarce and forage for insect prey is reduced in calcium, nestling egrets are at risk for developing secondary nutritional hyperparathyroidism.

Texas↗
USGS2022

Extending body condition scoring beyond measurable rump fat to estimate full range of nutritional condition for moose

Moose ( Alces alces ) populations along the southern extent of their range are largely declining, and there is growing evidence that nutritional condition — which influences several vital rates – is a contributing factor. Moose body condition can presently be estimated only when there is measurable subcutaneous rump fat, which equates to animals with >6% ingesta-free body fat (IFBFat). There is need for a technique to allow body fat estimation of animals in poorer body condition (i.e., <6% body fat). We advance current methods for moose, following those used and validated with other ungulate species, by establishing a moose-specific body condition score (BCS) that can be used to estimate IFBFat in the lower range of condition. Our modified BCS was related strongly ( r 2 = 0.89) to IFBFat estimates based on measurable rump fat. By extending the predicted relationship to individuals without measurable fat, the BCS equated severe emaciation with 0.67% IFBFat, supporting the accuracy of the method. The lower end of nutritional condition is important for identifying relationships involving life-history characteristics because most state-dependent changes occur at lower levels of condition. Therefore, until the BCS can be validated with moose carcasses, we believe our method to estimate body fat across the full range of condition should yield better understanding of the drivers underlying declining moose populations.

Alces↗
USGS2025

Sapsucker wells as a keystone nutritional resource: Evaluating methods for detection of secondary sap consumers

North American sapsuckers are considered double keystone species because they (1) excavate nest cavities that are used by other birds, small mammals, and invertebrates, and (2) create and maintain sap wells, a temporary nutritional resource available to a variety of secondary consumers. Most previous reports of secondary sap consumption relied on human observers and were based on either brief or incidental observations. However, modern technology can greatly enhance observational techniques and provide additional insights into the functional, community-level importance of sap wells. We used visual surveys, camera traps, and environmental DNA (eDNA) to identify secondary consumers of sap from wells created by red-naped ( Sphyrapicus nuchalis ) and Williamson's ( S. thyroideus ) sapsuckers among three functional groups of shrubs and trees in south-central Colorado: shrub willows ( Salix spp.), Rocky Mountain maple ( Acer glabrum ), and conifer trees (Pinopsida). Camera traps and eDNA revealed additional sap-well visitors not identified from direct observations. Camera traps were effective for detecting nocturnal sap-well visitors such as small rodents as well as occasional diurnal visitors. Environmental DNA analyses corroborated findings from other methods and identified four additional taxa as possible sap consumers. The physiology of sap-well visitors, such as the ability to taste and assimilate compounds within sap, may aid in determining consumption versus contact when evaluating the results of eDNA analyses. Total vertebrate taxa detected using all 3 methods included 17 bird taxa in 10 families within 3 orders and 8 mammal taxa in 6 families within 4 orders. Shrub-willow sap wells attracted the most diverse vertebrate taxa (23), followed by Rocky Mountain maple (13) and conifer trees (10). Invertebrates in 13 families within 3 orders were observed feeding from sap wells during visual surveys. Because many secondary sap consumers perform ecological services such as pollination, seed dispersal, and pest control, the methods described here may aid in elucidating the importance of sap-well creators in supporting biodiversity and ecosystem functioning.

Colorado↗
USGS2014

Testing the nutritional-limitation, predator-avoidance, and storm-avoidance hypotheses for restricted sea otter habitat use in the Aleutian Islands, Alaska

Sea otters ( Enhydra lutris) inhabiting the Aleutian Islands have stabilized at low abundance levels following a decline and currently exhibit restricted habitat-utilization patterns. Possible explanations for restricted habitat use by sea otters can be classified into two fundamentally different processes, bottom-up and top-down forcing. Bottom-up hypotheses argue that changes in the availability or nutritional quality of prey resources have led to the selective use of habitats that support the highest quality prey. In contrast, top-down hypotheses argue that increases in predation pressure from killer whales have led to the selective use of habitats that provide the most effective refuge from killer whale predation. A third hypothesis suggests that current restricted habitat use is based on a need for protection from storms. We tested all three hypotheses for restricted habitat use by comparing currently used and historically used sea otter foraging locations for: (1) prey availability and quality, (2) structural habitat complexity, and (3) exposure to prevailing storms. Our findings suggest that current use is based on physical habitat complexity and not on prey availability, prey quality, or protection from storms, providing further evidence for killer whale predation as a cause for restricted sea otter habitat use in the Aleutian Islands.

Alaska↗
USGS1992

Nutritional value of dietary nucleic acids and purine bases to rainbow trout (Oncorhynchus mykiss)

Rainbow trout were fed diets with graded levels (0.6%, 1.6%, 2.5%, and 4.1%) of a yeast nucleic acid extract corresponding to dietary Saccharomyces cerevisiae levels of 7.5%, 20%, 30% and 50% or diets supplemented isonitrogenously (0.8% N) with free purines (adenine, guanine, xanthine, and hypoxanthine) in two 12-week studies. Fish fed increasing levels of yeast extract manifested significant ( P < 0.05) corresponding incremental increases in growth and nitrogen retention. No negative effects on feed intake were observed. When fish were fed supplemental free purines, adenine was shown to be a potent inhibitor of feed intake and growth. While supplementation with the remaining purines did not negatively affect feed intake or growth, carcass nitrogen retention was significantly depressed, indicating the lack of a nitrogen-sparing effect. Our results indicate that the nutritional significance of free dietary adenine versus nucleic acid-bound adenine in yeast or yeast nucleic acid is an important consideration in evaluating the suitability of single cell proteins in fish feed formulations.

Aquaculture↗
USGS1982

Amino acid nutrition of fishes: requirements and supplementation of diets

The purpose of this paper is: (1) to make a concise review of the published dietary requirements of fishes for amino acids, (2) to describe recent findings at the Tunison Laboratory concerning amino acid nutrition of trout, (3) to review specific signs of deficiency of amino acids, and (4) to discuss use of the fish egg amino acid pattern as a guideline to formulating new feeds or studying amino acid requirements of fishes for which there is limited information on their quantitative requirements.

Comparative Biochemistry and Physiology, Part B: C↗
USGS2019

Examination of Bathymodiolus childressi nutritional sources, isotopic niches, and food-web linkages at two seeps in the US Atlantic margin using stable isotope analysis and mixing models

Chemosynthetic environments support distinct benthic communities capable of utilizing reduced chemical compounds for nutrition. Hundreds of methane seeps have been documented along the U.S. Atlantic margin (USAM), and detailed investigations at a few seeps have revealed distinct environments containing mussels, microbial mats, authigenic carbonates, and soft sediments. The dominant mussel, Bathymodiolus childressi , contains methanotrophic endosymbionts but is also capable of filter feeding, and stable isotope analysis (SIA) of mussel-shell periostracum suggests that these mussels are mixotrophic, assimilating multiple food resources. However, it is unknown whether mixotrophy is widespread or varies spatially and temporally. We used SIA (δ 13 C, δ 15 N, and δ 34 S) and an isotope mixing model (MixSIAR) to estimate resource contribution to B. childressi and characterize food webs at two seep sites (Baltimore Seep; 400 m and Norfolk Seep; 1500 m depths) along the USAM, and applied a linear mixed-effects model to explore the role of mussel population density and tissue type in influencing SIA variance. After controlling for location and temporal variation, isotopic variability was a function of proportion of live mussels present and tissue type. Isotopic differences were also spatially discrete, possibly reflecting variations in the underlying carbon source at the two sites. Low mussel δ 13 C values (∼−63‰) are consistent with a dependence on microbial methane. However, MixSIAR results revealed mixotrophy for mussels at both sites, implying a reliance on a mixture of methane and phytoplankton-derived particulate organic material. The mixing model results also reveal population density-driven patterns, suggesting that resource use is a function of live mussel abundance. Mussel isotopes differed by tissue type, with gill having the lowest δ 15 N values relative to muscle and mantle tissues. Based on mass balance equations, up to 79% of the dissolved inorganic carbon (DIC) of the pore fluids within the anaerobic oxidation of the methane zone is derived from methane and available to fuel upper slope deep-sea communities, such as fishes ( Dysommina rugosa and Symphurus nebulosus ), echinoderms ( Odontaster robustus , Echinus wallisi , and Gracilechinus affinis ), and shrimp, ( Alvinocaris markensis ). The presence of these seeps thereby increases the overall trophic and community diversity of the USAM continental slope. Given the presence of hundreds of seeps within the region, primary production at seeps may serve as an important, yet unquantified, energy source to the USAM deep-sea environment.

Delaware, Maryland, North Carolina, Virginia↗
USGS2021

Substitution of inland fisheries with aquaculture and chicken undermines human nutrition in the Peruvian Amazon

With declining capture fisheries production, maintaining nutrient supplies largely hinges on substituting wild fish with economically comparable farmed animals. Although such transitions are increasingly commonplace across global inland and coastal communities, their nutritional consequences are unknown. Here, using human demographic and health information, and fish nutrient composition data from the Peruvian Amazon, we show that substituting wild inland fisheries with chicken and aquaculture has the potential to exacerbate iron deficiencies and limit essential fatty acid supplies in a region already experiencing high prevalence of anaemia and malnutrition. Substituting wild fish with chicken, however, can increase zinc and protein supplies. Chicken and aquaculture production also increase greenhouse gas emissions, agricultural land use and eutrophication. Thus, policies that enable access to wild fisheries and their sustainable management while improving the quality, diversity and environmental impacts of farmed species will be instrumental in ensuring healthy and sustainable food systems.

Peruvian Amazon↗
USGS2024

Inland recreational fisheries contribute nutritional benefits and economic value but are vulnerable to climate change

Inland recreational fishing is primarily considered a leisure-driven activity in freshwaters, yet its harvest can contribute to food systems. Here we estimate that the harvest from inland recreational fishing equates to just over one-tenth of all reported inland fisheries catch globally. The estimated total consumptive use value of inland recreational fish destined for human consumption may reach US$9.95 billion annually. We identify Austria, Canada, Germany and Slovakia as countries above the third quantile for nutrition, economic value and climate vulnerability. These results have important implications for populations dependent on inland recreational fishing for food. Our findings can inform climate adaptation planning for inland recreational fisheries, particularly those not currently managed as food fisheries.

Nature Food↗
USGS1993

Roles of diet protein and temperature in the growth and nutritional energetics of the slider turtle, Trachemys scripta

We determined the effects of dietary protein and T a on growth rates, food consumption rates, digestion rates, and digestive efficiencies of juvenile slider turtles ( Trachemys scripta ). Results from this study provide a clearer understanding of how these environmental factors interact in influencing body sizes and growth rates of individuals in wild slider turtle populations. Changes in plastron length, carapace length, and body mass were significantly greater for T. scripta eating 25% and 40% crude protein diets than for those eating 10% crude protein. Those consuming 10% crude protein showed significant decreases in body mass and plastron length over a 13-wk period. Individuals at T a 's of 15°, 22°, 28°, or 34° C had food ingestion rates (kJ wk⁻¹) that increased markedly with an increase in T a . Increasing dietary crude protein concentration increased turtle ingestion rates and influenced the positive effect of T a . Increasing dietary crude protein concentration alone did not significantly affect turtle consumption rates but did significantly influence the positive effect of T a . Digestive efficiencies were very high (because of the pelleted diet). Those turtles that ate at 15° C had a digestive efciency of 99.5%, as compared with 98.3% at 22° C, 94.8% at 28° C, and 95.8% at 34° C. Dietary protein concentration did not influence the digestive efficiencies of T. scripta. These data suggest that dietary protein is an important nutritional component to the growth of juvenile slider turtles and that elevated thermal conditions, combined with a high dietary protein availability, may explain the very high growth rates of slider turtles in some wild populations.

Alabama, Louisiana, South Carolina↗
USGS2008

Characterizing the nutritional strategy of incubating king eiders Somateria spectabilis in northern Alaska

We measured plasma concentrations of variables associated with lipid metabolism (free fatty acids, glycerol, triglyceride, and ??- hydroxybutyrate), protein metabolism (uric acid), and baseline corticosterone to characterize the nutritional state of incubating king eiders Somateria spectabilis and relate this to incubation constancy at two sites, Kuparuk and Teshekpuk, in northern Alaska. King eiders at both sites appeared to employ a partial-income incubation strategy, relying on both endogenous and exogenous energy resources. Females maintained high invariant levels of free fatty acids, ??-hydroxybutyrate, and glycerol throughout incubation, indicating that fat reserves were a major energy source, and not completely depleted during incubation. Similarly, uric acid did not increase, suggesting effective protein sparing or protein ingestion and adequate lipid reserves throughout incubation. Baseline corticosterone and triglyceride levels increased during incubation, indicative of an increase in foraging during late stages of incubation. Incubating females at Kuparuk had higher triglyceride concentrations but also had higher ??-hydroxybutyrate concentrations than females at Teshekpuk. This dichotomy may reflect a short-term signal of feeding overlaying the longer-term signal of reliance on endogenous lipid reserves due to higher food intake yet higher metabolic costs at Kuparuk because of its colder environment. Incubation constancy was not correlated with plasma concentrations of lipid or protein metabolites. ?? 2008 The Authors.

Journal of Avian Biology↗
USGS2022

Physiological and nutritional constraints on zooplankton productivity due to eutrophication and climate change predicted using a resource-based modeling approach

Emerging evidence suggests that zooplankton production is affected by physiological and nutritional constraints due to climate change and eutrophication, which in turn could have broad implications for food-web dynamics and fisheries production. In this study, we developed a resource-based zooplankton production dynamics model that causally links freshwater cladoceran and copepod daily production-to-biomass (P/B) ratios with water temperature, phytoplankton biomass and community composition, and zooplankton feeding selectivity. This model was used to evaluate constraints on zooplankton growth under four hypothetical scenarios: involving natural plankton community seasonal succession; lake fertilization to enhance fisheries production; eutrophication; and climatic warming. Our novel modeling approach predicts zooplankton production is strongly dependent on seasonal variation in resource availability and quality, which results in more complex zooplankton dynamics than predicted by simpler temperature dependent models. For mesotrophic and hypereutrophic lakes, our study suggests that the ultimate control over zooplankton P/B ratios shifts from physiological control during colder periods to strong resource control during warmer periods. Our resource-based model provided important insights into the nature of biophysical control of zooplankton under a changing climate that has crucial implications for food web energy transfer and fisheries production.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2006

Pathogens, nutritional deficiency, and climate influences on a declining moose population

Several potential proximate causes may be implicated in a recent (post-1984) decline in moose ( Alces alces andersoni ) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white-tailed deer ( Odocoileus virginianus ), negative effects of climate change, increased food competition with deer or moose, legal or illegal hunting, and increased predation by gray wolves ( Canis lupus ) and black bears ( Ursus americanus ). Long-standing factors that may have contributed to the moose decline include those typically associated with marginal habitat such as nutritional deficiencies. We examined survival and productivity among radiocollared ( n = 152) adult female and juvenile moose in northwest Minnesota during 1995–2000, and assessed cause of death and pathology through carcass necropsy of radiocollared and non-radiocollared animals. Aerial moose surveys suggested that hunting was an unlikely source of the numerical decline because the level of harvest was relatively low (i.e., approx. 15% / 2 yr) and the population usually grew in years following a hunt. The majority of moose mortalities (up to 87% of radiocollared moose [ n = 76] and up to 65% of non-radiocollared moose [ n = 84]) were proximally related to pathology associated with parasites and infectious disease. Liver fluke ( Fascioloides magna ) infections apparently constituted the greatest single source of mortality and caused significant pathology in the liver, thoracic and peritoneal cavities, pericardial sac, and lungs. Mortality due to meningeal worm ( Parelaphostrongylus tenuis ) was less prevalent and was manifested through characteristic neurological disease. Several mortalities apparently were associated with unidentified infectious disease, probably acting in close association with malnutrition. Bone-marrow fat was lower for moose dying of natural causes than those dying of anthropogenic factors or accidents, implying that acute malnutrition contributed to moose mortality. Blood profiles from live-captured animals indicated that those dying in the subsequent 18 months were chronically malnourished. Relative to other populations, average annual survival rates for adult females (0.79 [0.74–0.84; 95% CI]) and yearlings (0.64 [0.48–0.86]) were low, whereas those for calves (0.66 [0.53–081]) were high. Pregnancy (48%) and twinning (19%) rates were among the lowest reported for moose, with reproductive senescence among females being apparent as early as 8 years. Pregnancy status was related to indices of acute (i.e., bone-marrow fat) and chronic (i.e., blood condition indices) malnutrition. Opportunistic carcass recovery indicated that there likely were few prime-aged males (>5 yr old) in the population. Analysis of protein content in moose browse and fecal samples indicated that food quality was probably adequate to support moose over winter, but the higher fecal protein among animals that died in the subsequent 18 months could be indicative of protein catabolism associated with malnutrition. Trace element analysis from moose livers revealed apparent deficiencies in copper and selenium, but there was limited evidence of direct association between trace element concentrations and moose disease, pathology, or mortality. Time-series analysis of regional moose counts (1961–2000) indicated that annual population growth rate was related negatively to mean summer temperature, with winter and summer temperatures increasing by an average of 6.8 and 2.1 C, respectively, during the 40-year period. This change may have increased moose thermoregulatory costs and disrupted their energy balance, and thereby reduced their fitness. Time-series analysis failed to show a relationship between annual population growth rate and moose or deer abundance, indicating that food limitation via resource competition was unlikely. Population viability analyses, using count data (1961–2000) and demographic data collected during this study, suggested that the northwest Minnesota moose population likely would not persist over the next 50 years. More broadly, we conclude that the southern distribution of moose may become restricted in areas where climate and habitat conditions are marginal, especially where deer are abundant and act as reservoir hosts for parasites.

Minnesota↗
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↗
USGS2006

Assessing the nutritional stress hypothesis: Relative influence of diet quantity and quality on seabird productivity

Food availability comprises a complex interaction of factors that integrates abundance, taxonomic composition, accessibility, and quality of the prey base. The relationship between food availability and reproductive performance can be assessed via the nutritional stress (NSH) and junk-food (JFH) hypotheses. With respect to reproductive success, NSH posits that a deficiency in any of the aforementioned metrics can have a deleterious effect on a population via poor reproductive success. JFH, a component of NSH, posits specifically that it is a decline in the quality of food (i.e. energy density and lipid content) that leads to poor reproductive success. We assessed each in relation to reproductive success in a piscivorous seabird, the black-legged kittiwake Rissa tridactyla . We measured productivity, taxonomic composition, frequency, size, and quality of meals delivered to nestlings from 1996 to 1999 at 6 colonies in Alaska, USA, 3 each in Prince William Sound and Lower Cook Inlet. Productivity varied widely among colony-years. Pacific herring Clupea pallasi , sand lance Ammodytes hexapterus , and capelin Mallotus villosus comprised ca. 80% of the diet among colony-years, and each was characterized by relatively high energy density. Diet quality for kittiwakes in this region therefore remained uniformly high during this study. Meal delivery rate and meal size were quite variable among colony-years, however, and best explained the variability in productivity. Parent kittiwakes appeared to select prey that were energy dense and that maximized the biomass provisioned to broods. While these results fail to support JFH, they do provide substantial support for NSH.

Marine Ecology Progress Series↗
USGS2023

Outlining potential biomarkers of exposure and effect to critical minerals: Nutritionally essential trace elements and the rare earth elements

Emerging and low-carbon technologies and innovations are driving a need for domestic sources, sustainable use, and availability of critical minerals (CMs)—those vital to the national and economic security of the United States. Understanding the known and potential health effects of exposures to such mineral commodities can inform prudent and environmentally responsible handling and harvesting. We review the occurrence, use, predominant exposure pathways, and adverse outcome pathways (AOP) for human and fish receptors of those CMs that are nutritionally essential trace metals (specifically, cobalt, chromium, manganese, nickel, and zinc), as well as the rare earth elements. Biological responses to some elements having comparable biogeochemistry can sometimes be similar. Candidate quantifiable biomarkers for assessing potential AOP are conveyed.

Toxics↗
USGS1957

The nutrition of salmonid fishes. I. Chemical and histological studies of wild and domestic fish

Salmonids reared under artificial conditions show marked consistent differences in body composition in comparison with wild salmonids. Protein and mineral levels are lower and lipid values are higher in hatchery fish than in wild fish. As the period of artificial rearing is increased, these differences become more extreme. In hatchery fish, there is generally more microscopically visible fat in the liver and viscera than in these organs in wild fish although extremes are seen in both groups. In young hatchery fish and in wild fish, there is no correlation between fat deposition in the liver and in the pancreas, but in older hatchery fish, both of these organs are fatty and there is a simultaneous increase in total body lipid. In wild fish, ceroid deposition is greater, suggesting that the fatty acids are more highly unsaturated. There is little difference in disease incidence between the two groups, but parasitism is more pronounced in wild fish. The significant variables between wild and artificially produced fish appear to be limited to diet and environment. From the factors discussed above, diet alone is probably the most important single factor in producing the changes observed in body composition.

Alaska, British Columbia, California, Oregon, Wash↗