Food Particle Size Research Articles

Effects of food particle size on Perca fluviatilis larval growth

The effects of the size of food particles on the uptake of an artificial diet by perch (Perca fluviatilis) larvae, reared in tanks for 15 days following hatching, were studied. Perch accepted a dry diet with particles smaller than 200μm. Average survival rates ranged from 11 to 25% with daily specific growth of 0.03mm and 0.08mg in length and weight, respectively. There were no significant differences in the growth of perch fed with food particle sizes in the ranges 0–80, 80–125, 125–160 and 160–200μm. The best results were obtained, nevertheless, with particle sizes smaller than 125μm during the first week and larger than 125μm in the second week. The mouth size of larvae doubled from 0.36 to 0.75mm and showed a significant and positive correlation with larvae length. At the and of the experiment, the lipids content in larvae was measured, especially the triacylglycerols fraction. The saturated and mono-unsaturated fatty acids in larvae reflected those in their food. The unsaturated C22 : 6 (n-3) and C18 : 2 (n-6) were the main component of n-3 and n-6 fatty acids series in perch.

「きざみ食」に関する基礎的研究 （第１報） そしゃく後の食品の大きさの測定

「きざみ食」に関する基礎的研究 （第１報） そしゃく後の食品の大きさの測定

Effects of food particle size on

Effects of food particle size on

Comparative morphology of the feeding basket of five species of Euphausia (Crustacea, Euphausiacea) in the western North Pacific, with some ecological considerations

The feeding basket morphology and stomach content analyses of five Euphausia species (E. recurva, E. nana, E. pacifica, E. mutica and E. similis) were compared to elucidate their feeding ecology. The filter areas of feeding basket of E. pacifica and E. nana were proportionally larger than those of others in the size classes 13-20 mm and <13 mm, respectively, suggesting a high filtering efficiency in these species at each size class. Based on the secondary setal distance, it is suggested that there are three types of feeding basket in five Euphausia species. One is the fine mesh (<5 μm) of E. pacifica and E. nana; a second is the medium (10-20 μm) of E. recurva and E. mutica; and the third is the coarse (20-30 μm) of E. similis. The ability to feed on particles <5 μm would give both species, E. pacifica and E. nana, a great advantage over other species when number of flagellates is high. Stomach content analyses indicated a more omnivorous feeding mode in E. mutica, E. recurva and E. similis and a more herbivorous in E. pacifica and E. nana. This is in agreement with morphological studies of feeding baskets. Increments in the primary and secondary setal distances with increasing size of four Euphausia species, except E. pacifica, were evident, reflecting interspecific differences in food particle sizes utilized. In E. pacifica, however, the morphological similarity should produce intraspecific competition in diet.

An optimization model for mastication and swallowing in mammals.

Mammalian mastication is a process combining simultaneous food comminution and lubrication. The initiation of swallowing, which is voluntary, has been thought to depend on separate thresholds for food particle size and for particle lubrication. Instead of this duality, we suggest that swallowing is initiated when it is sensed that a batch of food particles is binding together under viscous forces so as to form a bolus. Bolus formation ensures that when the food mass is swallowed, it will pass the pharyngeal region safely without risk of inhaling small particles into the lower respiratory tract. Crucial for bolus formation is food particle size reduction by mastication. This allows the tongue to pack particles together tightly by pressure against the hard palate. A major function of salivation is to fill the gradually reducing spaces between particles, so increasing viscous cohesion and promoting bolus formation. If swallowing is delayed, excessive saliva floods the bolus, separating particles and reducing cohesion. Swallowing then becomes more precarious. Our model suggests that there is an optimum moment for a mammal to swallow, defined in terms of a peak cohesive force between food particles. The model is tested on human mastication with two foods, brazil nut and raw carrot, which have very different particle size breakdown rates. The peak cohesive force is much greater with brazil nuts but both foods are predicted to be swallowed after similar numbers of chews despite the very different food particle size reductions achieved at that stage. The predicted number of chews to swallow is in broad agreement with published data.

Management of size variation in juvenile gilthead sea bream ( Sparus aurata). I: Particle size and frequency of feeding dry and live food

The effects of particle size and frequency of feeding on survival, growth and growth depensation of juvenile gilthead sea bream were investigated in three separate experiments. In the first experiment the effects of dry food particle size and frequency of feeding were investigated with all treatments being equally supplemented with Artemia. Growth depensation, measured as the change in the coefficient of variation of mean weight (ΔCV), was affected by particle size but not by frequency of feeding. Frequency of feeding did, however, have a significant effect on growth rate. In the second experiment the effects of feeding brine shrimp, Artemia, as a supplemental feed were tested. Feeding continuously with brine shrimp resulted in a lower ΔCV than periodic feeding (ΔCV values of 15.6 vs. 21.8%, respectively). In the third experiment the effect of feeding Artemia as the sole source of food was tested. Continuous feeding resulted in a seven-fold higher ΔCV as compared to periodic feeding (ΔCV values of 24.6 vs. 3.6%, respectively). Competitive interactions between individuals of different size, and the differential attraction of fish to dry pellets and live food, are discussed as possible behavioral mechanisms underlying the results. Careful management of food administration (i.e. feeding frequency and particle size) could reduce the need for labor-intensive and stressful size-grading during nursing.

Food-particle size and selection by bivalve larvae in a temperate embayment

Epifluorescence microscopy was used to analyze the stomach contents of bivalve larvae collected in the Baie des Chaleurs (western Gulf of St. Lawrence, Canada) in order to document food-particle sizes, compare feeding among taxa, and compare the diet with the in situ phytoplankton community. Stomach contents were mainly composed of small autotrophic flagellates (<5 μm) and cyanobacteria (<2 μm), reflecting the microbial food web which characterizes these waters. More than half (55%) of all veligers examined contained algal cells of 5 to 15 μm, whereas only 3% had cells of 15 to 25 μm. Differences in the size ranges of ingested algal cells among similar-sized larvae of different species suggests that veligers actively selected food particles. Among the smallest veligers (185 to 260 μm), scallops (Placopecten magellicanus) and mussels (Mytilus edulis) ingested more <5 μm and 5 to 15 μm algae than clams (Mya arenaria). Among larger veligers (261 to 405 μm), clams contained significantly more <5 μm cells than mussels, whereas mussels contained significantly more 5 to 15 μm algae than clams. Algal cells of 15 to 25 μm were preferentially ingested by mussel veligers. Feeding also differed between different-sized veligers within taxa, i.e. the smallest clam veligers ingested fewer of 5 to 15 μm algae than the larger size classes. Mussel veligers ingested significantly more 15 to 25 μm and fewer <5 μm cells as their size increased. The dominance of ultraplankton in the nearshore waters of Baie des Chaleurs and in the stomach contents suggests that veliger larvae may be an important export path for carbon produced by small phytoplankton.

Feeding Behavior of Dipolydora commensalis (Polychaeta: Spionidae): Particle Capture, Transport, and Selection

Feeding Behavior of Dipolydora commensalis (Polychaeta: Spionidae): Particle Capture, Transport, and Selection

Mouthparts of Three Collembolan Species: Comparative Morphology

The mouthparts (labrum, mandibles, and maxillae) of three litter-dwelling collembolan species-Orchesella hexfasciata (Entomobryidae), Isotoma notabilis (Isotomidae), and Sminthurinus henshawi (Sminthuridae)-are described, using both light and scanning electron microscopy. The right molar plate of all three species bears a projection that fits into a corresponding depression on the left molar plate, a previously unnoticed but possibly common and important feature. Based on the free-standing nature of molar plate rods, we suggest a brushing rather than a grinding function. The mouthparts of these species are structurally very similar, but differ in size. Size of labrum and mandibles probably dictates the size of food particles ingested. The rake-like structure of lamella 1 on the maxillar head of L. notabilis may explain why the gut contents of this species consist largely of colloidal material. Additional key words: labrum, mandible, maxilla, Orchesella, Isotoma, Sminthurinus Collembolans are dominant arthropods in terrestrial detritus-based food webs, both in terms of population density and species richness. They have an integral role in maintaining and shaping microbial activity and community structure, and are important mediators of food web stability (Moore et al. 1988). The functional importance of collembolans in decomposition processes is closely associated with their feeding activities (Seastedt 1984). Some significant contributions on the structure and function of collembolan mouthparts include Folsom (1899, 1900), Hoffman (1905, 1908), Borner (1908, 1909), Denis (1928), Wolter (1963), Manton (1964), Goto (1972), and Chaudonneret (1973). Although the link between mouthpart structure and feeding habits has long been recognized (MacNamara 1924; Fjellberg 1985), no attempt has been made to investigate the relationship between detailed mouthpart morphology and food selection. During an investigation of food partitioning in litter-dwelling collembolans (Chen et al. 1996), we studied the morphology of the labrum, mandibles, and maxillae of three collembolan species common in deciduous forest, using both light and scanning electron microscopy. Collembolans possess an entognathous mouth, mandibles and maxillae being enclosed by the head capsule. Two general mouth types are recognized, depending on whether mandibular molar plates are present (chewing type) or absent (sucking type). Collembolans a Author for correspondence. E-mail: 23118MGR@msu.edu with mandibular molar plates use their mouthparts (mainly mandibles and maxillae) to chew, grind, and/or tear food material before ingesting it. The tips of the mandibles can scratch the food surface, and mandibles and maxillae can also reach out, grasp, and carry food back into the mouth. Movement of mandibles and maxillae is restricted by surrounding structures such as labrum, labium, and the lateral margins of the gnathal pouch (Manton 1964). Shape and size of mandibles and labrum may restrict type and particle size of ingested food (Fjellberg 1985). Although constructed according to the same general model, the feeding apparatus varies among species even in closely related groups (Fjellberg 1984).

Diets of calanoid copepods on the West Florida continental shelf: Relationships between food concentration, food composition and feeding activity

Bottle incubations were conducted in March, July/August and October 1992. to measure the daily rations (R) and objectively characterize the diets of the calanoid copepodsEucalanus elongatus, Undinula vulgaris, Centropages velificatus andTemora stylifera from the west Florida continental shelf. Daily rations,R, were clustered around two, order-of-magnitude different means, 1.3 and 11.2% of body C d−1, representative of quiescent and active feeding modes, respectively. The food concentration at which the transition from quiescent to active mode occurred was influenced by food particle size. In the quiescent mode, diets were dominated by nanoplankton, whereas no food type dominated the diet in the active mode. Selective feeding, defined as a statistically significant difference between the frequency distributions of foods in the diet and environment, occurred in both quiescent and active copepods. However, what appeared to be selective feeding in quiescent copepods could be explained by processes that passively modified the distribution of the diet relative to that of the food supply. Conversely, selective feeding in active copepods apparently resulted from foraging for particles >5 μm in diameter in food environments dominated by nanoplankton (<5 μm).

An Analytic Probability Density for Particle Size in Human Mastication

In previous studies the distribution of particles sizes of chewed food has been described by an empirical function. However, at the beginning of the chewing process, when many unbroken food particles are still present in the mixture, this function failed to give a good description. In the present study, formulae were derived to characterize the distribution of chewed food particles by size as a function of the number of chewing cycles. The reduction of food particle sizes was considered too be the composite result of a selection and a breakage process. Both processes were described by simple functions. The probability density P n +1( x) of finding a particle of size xafter n+ 1 chewing cycles was computed from P n ( x) by selecting a proportion of particles of size yfrom P n to be converted to particles of size x< yby a breakage function. Measures of central tendency—average, median, and most probable size—were obtained as a function of the number of chewing cycles. The measures of central tendency characterize the degree of food comminution during the chewing process and so can be used to quantify chewing performance. The comminution of food is described in terms of the selection and breakage functions in a convenient, efficient, analytic way, valid for all phases of the chewing process.

Feeding and Chewing Behaviours of Nubian Ibex: Compensation for Sex-Related Differences in Body Size

Size-related differences in digestive capabilities are thought to account for patterns of diet selection, social structure and habitat use by small- and large-bodied herbivores. We examined food processing behaviours that could compensate for digestive constraints resulting from the relative scaling of metabolic requirements and gut capacity with body mass. We observed feeding, chewing and ruminating behaviours of sexually size-dimorphic Nubian ibex fed diets chopped to a short (1-2 cm), medium (8 cm), or long (25 cm) length. These diets differed in the amount of oral processing needed for particle size reduction, bolus formation and swallowing. Food particle size did not affect intake rate (g/min) but chewing investment (chews/g) of both sexes was 30% less for the shortest hay. Rumination activity of both sexes approximated the maximum sustainable level of almost 10h/day for all diets. Chewing rates (chews/min) during rumination did not differ between males and females. Chewing investment of females was 40% greater than that of males while feeding and more than 50% greater while ruminating. Size-related differences in molar occlusal surface area (∼ 15%) were much too small to account for sex-related variation in chewing investment. Our results support the hypothesis that females enhanced digestion rates relative to those of larger-bodied males through increased oral processing.

Feeding of two mysid species on plankton in a temperate South African estuary

Two sympatric mysid species, Mesopodopsis wooldridgei and Rhopalophthalmus terranatalis, dominate mesozooplankton biomass in the Sundays River estuary, South Africa. This study aimed to investigate the food and feeding rates of the two mysids on naturally occurring phytoplankton and microzooplankton assemblages, and on copepod instars, using laboratory based feeding and predation experiments. Maximum clearance rates calculated for different size classes of M. wooldridgei on microplankton were on average 34.2, 15.8 and 18.6 ml ·. ind −1 ·. h −1 for adults, immatures and juveniles respectively. For the same R. terranatalis size classes clearance rates were 8.5, 13.0 and 13.5 ml ·. ind 1̄ ·. h −1 respectively. Thus, all size classes of the smaller M. wooldridgei had higher maximum clearance rates compared to any of the stages of the larger R. terranatalis, indicating that the former species fed more successfully on phyto- and microzooplankton and that these prey assemblages probably constitute the lower limit of the food particle size range consumed by the latter species. R. terranatalis is more successful in preying on larger plankton such as adult copepods and juvenile mysids. Microzooplankton was generally more important in mysid diet than phytoplankton. Apparent selection for microzooplankton species was probably due to an inability to feed efficiently on the smaller phytoplankton cells. Copepod nauplii were readily consumed by all mysid size classes. Predation rates, in terms of weight specific carbon ingestion, increased linearly with copepod instar prey concentration.

Aktivitätsrhythmus von Brandgänsen (Tadorna tadorna) und Watvögeln (Charadrii) an der Nordseeküste

Shelducks, Oystercatchers, Grey Plovers, Knots, Dunlins, Bar-tailed Godwits, Curlews, Spotted Redshanks, Redshanks, and Greenshanks showed a tidal rhythm of time-activity budgets on the Wadden Sea coast during the non-breeding season. Ringed Plovers and Ruffs did not react to the tidal rhythm. Night-time feeding could be observed in most species. Differences in the time-activity budgets of the species were related to body mass and size of food particles. Inter-site comparisons revealed that technical constructions for coastal protection influenced the activity rhythms of the birds.

Eoparisocrinid crinoids from the Middle Ordovician (Galena Group) of northern Iowa and southern Minnesota

Two species of eoparisocrinid crinoids from the Middle Ordovician Galena Group of northern Iowa and southern Minnesota are described, namelyEoparisocrinus crossmanin. sp. andE. grandein. sp. The post-larval development ofEoparisocrinus crossmaniis examined. Crinoid arms grow by addition of new plates at their distal tips in conjunction with calcite deposition on old plates. New branches appear where axillary plates are initiated. Consequently, the growth rates for number of brachials and length of food-gathering system compared to crown volume are much faster than if the animals were isometric. The number of food particles collected is related to the number of food-catching tube-feet, which can be estimated if the length of the arms and height of the covering plates are known. The size of the largest food item is constrained by the food groove width. Thus, food-gathering capacity is the number of food-catching tube-feet multiplied by food groove width. The food-gathering capacity increases more rapidly than if the animal grew isometrically, and the ratio of food-gathering capacity: crown volume only declines slightly over the known growth range. All Ordovician cladid crinoids examined follow nearly identical ontogenetic trajectories. The ecological niche of a stalked crinoid is related to four basic parameters: stem length, food groove width, tube-foot spacing, and branch density. Stem length limits the highest elevation above the seafloor. The column ofE. crossmanibecomes longer during ontogeny due to the formation of new columnals and height growth of old ones. Consequently, individuals gradually “move up” until the adult elevation of about 50 mm is reached. The growth rates of stem length relative to crown size are slow in the youngest and mature animals but rapid in juveniles. The food grooves become wider throughout growth so that older crinoids ate larger food particles than younger ones. The food groove width increases less rapidly than if the shape were constant, because distal plates and branches are more narrow and have more slender food grooves than proximal plates. Growth curves for food groove width versus stem length and elevation were generated forE. crossmaniand other crinoids that commonly occur in the same beds. Together, elevation and food particle size define the main dimensions of the niche. The various taxa are more or less separated by different food groove widths at most comparable elevations. This pattern minimizes ecological overlap and probably competition between the different species. The tube-foot spacing ofE. crossmaniis constant regardless of size, which suggests that it employed the same type of feeding mechanism throughout post-larval ontogeny. The arm branches of adults gradually become less densely spaced relative to the area of water filtered than in juveniles.

Physiological Adaptations in the Gastrointestinal Tract of Crayfish

SYNOPSIS. Crayfish are the dominant macrocrustacean in many aquatic ecosystems and are the largest crustacean aquacultural industry in the United States, yet we know relatively little about their preferred and nutritionally important foods, as well as their ability to utilize those foods. This review focuses on the ability of crayfish to detect foods, reduce food particle size, digest macronutrients and the control of those functions. Of particular interest are the enzymatic capabilities of crayfish, especially trypsin, an alkaline protease, cellulase, muramidase, and possibly chitinase and chitobiase. The coordinated neural control of crayfish food location, ingestion and movement has been well documented, while hormonal control mechanisms have not. The conclusion we must draw from our current state of knowledge is that crayfish have ample abilities to taste and locate potential foods and enzymatic adaptations developed in crayfish that allow use of many of the foods they encounter in a benthic aquatic environment; other adaptations are lacking or have not been elucidated.

Simultaneous measurement of food particle selection and clearance rates of planktonic oligotrich ciliates (Ciliophora:Oligotrichina)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 119:125-137 (1995) - doi:10.3354/meps119125 Simultaneous measurement of food particle selection and clearance rates of planktonic oligotrich ciliates (Ciliophora: Oligotrichina) Kivi, K., Setälä, O. Oligotrich ciliates are a major microzooplankton component in the northern Baltic Sea during summer. The use of wheat starch particles as a tracer-level food source enabled us to simultaneously evaluate in situ clearance rates and food particle size selection of natural ciliate assemblages. Average clearance rates of 9 ciliates of the genera Lohmanniella, Strobilidium, Strombidium, Tintinnidium and Tintinnopsis on their most favored particle sizes ranged from 1.9 to 11.4 ul cell-1 h-1. Particle size selectivity was studied by the use of chi2-based selectivity index. Each species showed a specific particle size preference pattern. The optimal particle size varied from 1.4 um (Strombidium sp. 20 um in size) to 9.8 um (Strobilidium sp. 40 um). Most species were able to ingest effectively nanoflagellate-size food, but only 2 of the species showed effective grazing on the smallest particles, suggesting a possible ability to utilize bacteria-size prey. The overall ciliate food size spectrum covered the size range of the most abundant food items in the Baltic summer plankton. Among the ciliates investigated, there appears to be 2 different feeding strategies: specialistic and generalistic, where the ciliates either concentrate on feeding on a narrow size range of food organisms, or use food particles of a wide size range, with little or no preferences within this range. Ciliates . Grazing . Food selection Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 119. Publication date: March 23, 1995 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1995 Inter-Research.

Comparative morphology of the feeding appendages of four mesozooplankton species in the Sundays River estuary

The morphology of feeding appendages of the coexisting estuarine copepods, Pseudodiaptomus hessei and Acartia longipatetla, and mysids, Rhopalophthalmus terranatalis and Mesopodopsis wooldridgei. were examined and compared as an aid in elucidating dietary differences. The robust mandibles of P. hessei copepodids compared to the more pointed and slender teeth with no molar region, of A. longipatella suggest that the latter species relies on more fragile food particles. Mandible edge indices indicate, however, omnivorous feeding by both species. No clear dietary differences could be deduced from the dimensions of the second maxillae of these copepods. Mandible edge indices calculated for the mysid species suggest a more herbivorous feeding mode in M. wooldridgei and a more carnivorous one in R. terranatalis, supporting previous studies on their diets. No interspecific differences between the mysid size classes were evident from edge indices. Significant increments in setae and setule lengths and spacing with increasing mysid size class were evident, reflecting differences in food particle sizes utilized. The morphological differences in the feeding apparatus could reflect differences in the diets between species and indicate differences in food particle sizes utilized by the various developmental stages within species. These differences in diet should reduce inter- and intraspecific competition.

The association between chewing efficiency and occlusal contact area in man

Chewing is influenced by a number of factors, which include jaw and tongue movements, the activity of circumoral muscles, bite force and hard oral surfaces, but it is not clear which of these factors is most crucial to efficiency. The mere presence of surfaces such as the hard palate, or teeth, does not insure that chewing will be efficient. The purpose of this study was to explore the relationship between occlusal contact area, and chewing efficiency and to observe the influence of chewing-side preference on efficiency. These variables were recorded for both left- and right-hand sides, in a sample of 26 normal young adults. Chewing efficiency was estimated by the size of food particles collected after a predetermined number of chewing strokes. The particles were measured using image analysis and the median size calculated. Comparisons were made, firstly within subjects, between the left- and right-hand side, and secondly between subjects. Correlations were found between chewing efficiency and occlusal contact area which were more pronounced within, than between, subjects. It was concluded that while occlusal contact area influenced chewing efficiency within the same individual, it could not account for the differences in chewing efficiency found between individuals. Differences in the movement of the jaw and in the bite force may have a greater influence on chewing efficiency than occlusal contact area.

Patterns of growth and lipid deposition in cod ( Gadus morhua L.) fed natural prey and fish-based feeds

Groups of cod were fed two natural prey types, prawn and herring, and two herring-based wet diets, one with low and the other with high energy density. Cod fed upon whole herring and enriched-herring paste showed the highest growth rates but tended to store increasing amounts of lipid in the liver. Cod fed upon the leanest diet, prawn, showed, however, better efficiencies of energy and nutrient conversion. The effect of decreasing food particle size, by mincing the herring, was to slightly impair growth and to substantially lower the efficiency of food conversion. The fatty acid compositions of the body lipids tended to reflect dietary input. The major lipid class in the muscle was the phospholipid whereas the main lipid storage depot consisted of triacylglycerols in the liver. There were some indications that either 20:5 n−3 was chain elongated to 22:6 n−3, or was selective utilized. Dietary 22:1 appeared to have been used as an energy source by the cod, a predator that naturally feeds on prey such as herring which are rich in these fatty acids.