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Diet Items (diet + item)

Distribution by Scientific Domains
Life Sciences71%

Selected Abstracts

Ontogenetic diet shift in the June sucker Chasmistes liorus (Cypriniformes, Catostomidae) in the early juvenile stage

ECOLOGY OF FRESHWATER FISH, Issue 3 2010
J. D. Kreitzer
Kreitzer JD, Belk MC, Gonzalez DB, Tuckfield RC, Shiozawa DK, Rasmussen JE. Ontogenetic diet shift in the June sucker Chasmistes liorus (Cypriniformes, Catostomidae) in the early juvenile stage. Ecology of Freshwater Fish 2010: 19: 433,438. © 2010 John Wiley & Sons A/S Abstract,,, Ontogenetic diet shifts are common in fishes and often occur during early life stages. The larval and early juvenile period is critical in the life cycle of the endangered June sucker, Chasmistes liorus (Teleostei: Catostomidae). High larval and juvenile mortality leads to low recruitment to the breeding population and hence a declining natural population. To understand diet composition and dynamics in June sucker at early life stages, diet was quantified and compared to available food items in the natural environment during the early juvenile stage. Rotifers (Brachionus sp.) were the primary diet item at week 10, but by week 12 a small cyclopoid copepod (Microcyclops rubellus) became predominant. Availability of diet items varied little across the experimental period. The increase in size of young suckers may explain this rapid dietary shift, but there are some inconsistencies with the size selection argument. This diet shift represents an important nutritional change that should be considered in development of diets for young June sucker and in assessing suitability of nursery habitats. [source]

Bioaccumulation and trophic transfer of polychlorinated biphenyls by aquatic and terrestrial insects to tree swallows (Tachycineta bicolor)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2006
Jonathan D. Maul
Abstract Insectivorous passerines often bioaccumulate polychlorinated biphenyls (PCBs) via trophic transfer processes. Tree swallows (Tachycineta bicolor) frequently are used for estimating PCB bioaccumulation, yet the focus on specific trophic links between contaminated sediment and bird has been limited. Bioaccumulation of PCBs from sediment to tree swallows was examined with focus on trophic pathways by simultaneously examining PCBs in emergent aquatic and terrestrial insects and gut contents of nestlings. Total PCB concentrations increased from sediment (123.65 ± 15.93 ,g/kg) to tree swallow nestlings (2,827.76 ± 505.67 ,g/kg), with emergent aquatic insects, terrestrial insects, and gut content samples having intermediate concentrations. Biota-sediment accumulation factors (BSAFs) varied among congeners for tree swallow nestlings and for male and female Chironomus spp. For nestlings, the highest BSAF was for the mono- ortho -substituted congener 118. Nestling biomagnification values were similar for gut contents and female Chironomus spp., suggesting this diet item may be the main contributor to the overall PCB transfer to nestlings. However, gut content samples were highly variable and, on a PCB congener pattern basis, may have been influenced by other taxa, such as terrestrial insects. Considering dietary plasticity of many insectivorous birds, the present study suggests that a variety of potential food items should be considered when examining PCB accumulation in insectivorous passerines. [source]

Ontogenetic diet shift in the June sucker Chasmistes liorus (Cypriniformes, Catostomidae) in the early juvenile stage

ECOLOGY OF FRESHWATER FISH, Issue 3 2010
J. D. Kreitzer
Kreitzer JD, Belk MC, Gonzalez DB, Tuckfield RC, Shiozawa DK, Rasmussen JE. Ontogenetic diet shift in the June sucker Chasmistes liorus (Cypriniformes, Catostomidae) in the early juvenile stage. Ecology of Freshwater Fish 2010: 19: 433,438. © 2010 John Wiley & Sons A/S Abstract,,, Ontogenetic diet shifts are common in fishes and often occur during early life stages. The larval and early juvenile period is critical in the life cycle of the endangered June sucker, Chasmistes liorus (Teleostei: Catostomidae). High larval and juvenile mortality leads to low recruitment to the breeding population and hence a declining natural population. To understand diet composition and dynamics in June sucker at early life stages, diet was quantified and compared to available food items in the natural environment during the early juvenile stage. Rotifers (Brachionus sp.) were the primary diet item at week 10, but by week 12 a small cyclopoid copepod (Microcyclops rubellus) became predominant. Availability of diet items varied little across the experimental period. The increase in size of young suckers may explain this rapid dietary shift, but there are some inconsistencies with the size selection argument. This diet shift represents an important nutritional change that should be considered in development of diets for young June sucker and in assessing suitability of nursery habitats. [source]

Brook trout, Salvelinus fontinalis, microhabitat selection and diet under low summer stream flows

FISHERIES MANAGEMENT & ECOLOGY, Issue 3 2006
J. C. SOTIROPOULOS
Abstract, This study investigated the effects of low summer discharge on habitat, prey use and prey availability for age 1 brook trout, Salvelinus fontinalis (Mitchill), in two small streams in Massachusetts, USA. Stream discharge declined substantially from June to August, with corresponding decreases in microhabitat depth and velocity; but fish habitat preferences were consistent throughout the summer, with fish selecting deep, low current velocity locations. Invertebrate drift rate, drift density and trout stomach fullness were significantly greater in June than August samples. Diets were dominated by aquatic-derived prey (chironomid larvae and adult blackflies) in June, but terrestrial invertebrates were the most frequent diet items in August. Consistent occupancy of low-velocity, deep microhabitats with low invertebrate flux rates indicated that, despite variation in habitat and prey conditions, trout adopted a habitat-use strategy of minimising risks and energy costs rather than maximising forage gain. This observation is consistent with, and provides a potential explanation for, the low summer growth rates of brook trout observed in small streams. [source]

Brief communication: Puncture and crushing resistance scores of Tana river mangabey (Cercocebus galeritus) diet items

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009
Julie Wieczkowski
Abstract Cercocebus mangabeys are characterized by dental traits that have been interpreted as adaptations to eat hard diet items. Although there are data that mangabeys include a large proportion of fruit and especially seeds in their diets, no hardness measurements have been done on mangabeys' food items. This study measured puncture and crushing resistance of food items in the diet of the Tana River mangabey (C. galeritus). Feeding data were collected by the use of scan samples from one mangabey group from August 2000 to July 2001 and from July 2005 to June 2006. Food items were collected during the latter period only, and from the same tree in or under which mangabeys had been observed eating. A portable agricultural fruit tester was used to measure the puncture resistance of fruit and a valve spring tester was used to measure the crushing resistance of seeds. The average puncture resistance of fruit was 1.7 kg/mm2, and the average crushing resistance of seeds was 12.8 kg. There were no correlations between puncture resistance, crushing resistance, or all resistance scores and frequency contribution to the diet. Resistance scores measured in this study were within the range of hardness scores of fruit and exceeded hardness scores of seeds eaten by other hard object feeders. Although this study supports the interpretation that Cercocebus dental traits are adaptations to hard object feeding, future research should investigate other material properties of food, as well as the role hard diet items play in niche separation and as fallback foods. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source]

Fluoride ingestion from food items and dentifrice in 2,6-year-old Brazilian children living in a fluoridated area using a semiquantitative food frequency questionnaire

COMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 4 2009
Ana Paula Borges Miziara
Abstract,,, Objectives:, The aim of this study was to evaluate the fluoride intake of 2,6-year-old Brazilian children using a semiquantitative food frequency questionnaire (FFQ) which also estimated fluoride intake from dentifrice. Methods:, The FFQ was previously validated through application to 78 2,6-year-old Brazilian children and then administered to 379 children residing in an optimally fluoridated community in Brazil (Bauru, State of São Paulo). The FFQ was applied to the parents and used to estimate the food intake of the children. The constituents of the diet were divided into solids, water and other beverages. The fluoride content of the diet items was analyzed with the fluoride electrode. The questionnaire also estimated fluoride intake from dentifrice. Results:, The average (±SD) fluoride intake from solids, water, other beverages and dentifrice was 0.008 ± 0.005; 0.011 ± 0.004; 0.009 ± 0.014 and 0.036 ± 0.028 mg F/kg body weight/day, respectively, totalizing 0.064 ± 0.035 mg F/kg body weight/day. The dentifrice and the diet contributed with 56.3% and 43.7% of the daily fluoride intake, respectively. Among the children evaluated, 31.2% are estimated to have risk to develop dental fluorosis (intake>0.07 mg F/kg body weight/day). Conclusions:, The dentifrice was the main source of fluoride intake by the children evaluated. However, the fluoride concentration in food items also significantly contributed to the daily ingestion by 2,6-year-old children. The questionnaire used seems to be a promising alternative to duplicate diet to estimate the fluoride intake at this age range and may have potential to be used in broad epidemiological surveys. [source]