Rate Of Food Passage Research Articles

Impact of dietary allelochemicals on gypsy moth ( Lymantria dispar) caterpillars: importance of midgut alkalinity

Midgut pH of gypsy moth larvae was depressed artificially with buffered diet to examine the impact of alkalinity on the caterpillars' ability to tolerate a dietary polyphenol and a quinone. A 2×3 factorial design was used, with 2 levels of succinate buffer and 3 dietary amendments (tannic acid, juglone, or control). Development was monitored during the third and fourth instars, with consumption, food passage rates, midgut pH, and midgut redox potential (Eh) measured in the fourth instar. Diet buffering successfully depressed midgut pH to hypothetically suboptimal acidic levels without reductions in survivorship, but it did reduce larval growth and impede development. Buffering dramatically reduced survivorship of fourth instar larvae eating diets containing tannic acid or juglone. Growth increased on unbuffered diet amended with tannic acid, but not with juglone. Caterpillars passed food through the gut more slowly when feeding on buffered tannic acid diet or on unbuffered juglone diet. These results indicate that maintenance of midgut alkalinity is critical to tolerance of dietary tannic acid and juglone, and that these allelochemicals have very different activities in the caterpillar gut.

Temporal Patterns in Feeding of Grasshoppers (Orthoptera: Acrididae): Importance of Nocturnal Feeding

Rangeland grasshoppers were sampled from the Western High Plains ecoregion every 6 h over 2 periods of 2 d each during September 1992. The crop contents of the grasshoppers were classified as full (>80% filled), partially full (5–80% filled), or empty (>5% filled). Rangeland species often engaged in nocturnal feeding, in some cases more commonly than diurnal feeding. Across all species, 44% of individuals captured at midnight and sunrise had full crops, compared with 41% captured at midday and sunset. The frequencies of full and not-full (partially full and empty) crops across sampling times differed significantly between species and between sexes within 4 of the 5 dominant species. Laboratory bioassays of the rate of food (dyed filter paper) passage in field-collected grasshoppers, at 10, 21, and 32°(; during light and dark conditions, revealed that crops were emptied within 4 h of feeding. Seasonal and spatial variation in temporal feeding was studied at 3 sites in July, August, and September 1994. The temporal patterns of crop fullness differed significantly among species and sexes at each sampling location and date. The frequencies of full crops also differed significantly within males and females of most species between sampling dates (at a single site) and between sites (at a single date). Temporal feeding patterns were highly variable. Four types of feeding patterns were apparent: diurnal, nocturnal, continuous, and intermittent. Temporal niche partitioning resulted in constant feeding by a grasshopper assemblage. Nocturnal feeding was an important component of this partitioning; 78% of the classified cases involving substantial nocturnal feeding and 50–75% of all grasshoppers sampled had full crops at midnight and sunrise.

Digestion, defecation and food passage rate in the insectivorous bat Myotis myotis

The coefficient of dry mass digestibility (DMD) in the insectivorous bat Myotis myotis (Borkhausen, 1797), fed American cockroaches, is 69.3%. This is comparable with the average digestibility and assimilation coefficients in insectivorous mammals and birds, but it is much lower than estimated in previous studies on insectivorous bats. The rate of passage of food marked with basic fuchsin (t5=25, t50=44, t90=77 minutes) and the defecation rate indicate extremely rapid digestion of food, which is connected with the feeding and foraging strategies of insectivorous bats. It is concluded, that previous estimations of bats' food consumption under natural conditions were lowered by the assumption of high digestibility of food or insignificant amount of feces defecated outside the rest place.

Diets of fruit-eating birds: what are the causes of interspecific differences?

Differences in fruit choice among the bird species of a Spanish shrubland were related to the size of fruits and to the lipid content of pulp. Lipid-rich fruits were selected by the bird species with slower food passage rates through the digestive tract. These bird species also fed frequently on insects and seeds. Bird species with faster food passage rates fed less on insects and seeds, and ate mainly fruits with pulp poor in lipids (rich in sugars and water). Studies of digestion in birds indicate that lipids require slower food passage rates for efficient digestion and intestinal transport than simple sugars. The available evidence indicates that the European bird species that show stronger preferences for lipid-rich fruits are no better as seed dispersers, from the point of view of the plants, than species choosing lipidpoor fruits. Thus, the degree of frugivory of birds, their fruit choice patterns and their effects on seed dispersal do not seem to be related to each other in the ways expected by the early models of the evolution of fleshy fruits.

The influence of gut morphology on digestion time in raptors

1. 1. Raptor species (Falconiformes and Strigiformes) have been shown to differ in intestine length by as much as 50% independent of body size and these differences are thought to be related to foraging strategy. 2. 2. Unless rate of food passage is reduced, raptor species with short digestive tracts would be predicted to have lower digestive efficiency. 3. 3. European sparrowhawk, peregrine and hobby have a short small intestine relative to body size resulting in rapid digesta throughput and a short food retention time. The common buzzard, European kestrel and red kite have a long, high-capacity digestive tract with a corresponding long food retention time. 4. 4. There was no evidence for a compensatory mechanism by which food passage could be slowed in species with a relatively short digestive tract.

Digestive Efficiency and Rate of Food Passage in Oilbird Nestlings

Digestive Efficiency and Rate of Food Passage in Oilbird Nestlings

Rapid orocecal transit in chronically active persons with high energy intake

Although chronic physical activity by humans can raise energy requirements and energy intake severalfold above sedentary levels, whether these increases alter digestive strategy remains unknown. To investigate this possibility, food passage rate (mouth-to-large intestinal lactulose transit) and absorption (xylose) were compared in a cross section of young men chosen to represent a wide range of daily physical activity and food intake. In 20 men (energy intake 1,272-5,342 kcal/day), resting mouth-to-cecum transit was faster in high caloric consumers (r = -0.69, P less than 0.01). In contrast, xylose absorption (n = 26; measured either as urinary xylose excretion or integrated breath H2 production from the sugar) was unrelated to food intake. Dietary fiber intake was uncorrelated with energy intake. This apparent human digestive strategy of rapid transit across the gut absorptive surface, without a sacrifice in absorption, parallels the adaptations made by several animal species similarly faced with increased energy demand at constant fiber intake. We therefore conclude that the hyperphagia of chronic exercise in humans may be linked with significant gastrointestinal adaptations.

Response of chickens fed on hull-less barley to dietary β-glucanase at different ages

A high viscosity hull-less barley with or without β-glucanase supplementation was compared to wheat in diets given to broiler or Single Comb White Leghorn (SCWL) cockerels. Both genotypes fed on the unsupplemented hull-less barley had poorer gain and feed conversion, higher digesta viscosity, slower rate of food passage and lower fat digestibility than chicks given the enzyme-supplemented hull-less barley or wheat diets. These effects were largely confined to the early growth period (0–4 weeks) and, with the exception of higher digesta viscosity, disappeared with ageing. Streptococcus faecium colonization of the upper small intestine also declined with ageing in all treatments, but chicks given unsupplemented hull-less barley tended to have higher counts than those given the enzyme-supplemented hull-less barley or the wheat diet. Older chickens were apparently better able to cope with higher viscosity induced by feeding barley. Despite the slower growth and reduced nutrient requirements of SCWL chicks, they responded in a parallel fashion to broiler stock.

Infection byBeauveria bassiana ofLeptinotarsa decemlineata larvae as a consequence of fecal contamination of the integument followingper os inoculation

A study ofper os inoculated larvae was undertaken to determine if the entomopathogenic fungus,Beauveria bassiana, is able to infect the Colorado potato beetle,Leptinotarsa decemlineata, via the alimentary tract. Surface orper os inoculated larvae which were immediately surface sterilized post inoculation did not succumb to infection, whereas those larvae not sterilized became infected. Histological studies of fed or starved, agnotobiotic (with microbial flora) and axenic larvae revealed that conidia can germinate in the gut regardless of the presence of gut microflora. However, infection via the alimentary tract was never observed in fed larvae and only noted in a single starved individual. It is concluded that infections ofper os inoclated larvae occurred after surface contamination of the integument by viable conidia contained in the frass. The rate of food passage through the gut is probably important in preventingper os infections.

Tests of a Model of Food Passage Rates in Hummingbirds

Calcul du taux de passage alimentaire chez 2 especes d'oiseaux apres un repas unique ou une alimentation ad libitum. Etude du taux d'excretion, du taux de vidage du jabot, correlation avec la quantite d'aliment absorbee

Food consumption, assimilation and rate of food passage in the cape rock elephant shrew, Elephantulus edwardii (macroscelidea: Macroscelidinae)

1. 1. Food consumption, assimilation and passage rates of an elephant shrew, Elephantulus edwardii, on three natural diets (cockroaches, locusts and termites) and one artificial cereal diet (Pronutro) were compared. 2. 2. Daily food consumption varies significantly between the diets and was partly related to % assimilation, which was highest on Pronutro and cockroaches (71%) and lowest on termites (31%). 3. 3. Throughput times were estimated using soluble ( 51 Cr-EDTA) and particulate markers in the Pronutro diet. First appearance of the soluble marker (0.5 hr) was significantly earlier than for the particulate marker (1.85 hr); 50% appeared at 3.2 and 3.35 hr for the soluble and particulate markers, respectively. 4. 4. The distribution of particulate markers in the digestive tract showed some retention in the stomach, ileum and colon, but rapid movement through the duodenum and very little entry to the caecum.

WILD HORSES: SOCIAL COMPETITION AND POPULATION SIZE

This book, the latest contribution in the University of Chicago Press Wildlife Behavior and Ecology Series, is, like many of its predecessors, a detailed accounting of a long-term intensive field study of a single species. How do these and similar contributions differ from natural history monographs of previous eras, and what criteria should be used to evaluate the relative merits of today's contributions? Current monographs on the behavior and ecology of single species differ from their forerunners in that they generally address specific issues that are tied to modern theory rather than recount natural history observations in an unfocused way. It follows that these studies should be judged on the importance of the issues addressed and the manner in which the investigation was conceived, executed, analyzed and presented. Wild Horses is entertaining, valuable, and thought-provoking reading, because of the attention given by Berger to each of these factors. Berger's decision to investigate horses was a judicious one because of many important contrasts between the biology of horses and other mammals. For example, although horses are polygynous and males defend year-round harems from rival males, they do not exhibit sexual dimorphism in body size and weaponry. Most group-living ungulates defend their harems only seasonally, and in several mammalian taxa (such as ungulates and primates) there is a positive relationship between the presence of weaponry (enlarged teeth, horns, or antlers) and the degree of polygyny. Another significant comparison concerns dietary preferences. While most ungulates have four-part ruminant stomachs, horses (and other equids) possess monosacculated stomachs and are comparatively nonselective (roughage) feeders, with faster rates of food passage and higher rates of food intake than ruminants. The relationship between monomorphism and digestive efficiency, coupled with variation in habitat quality, sets the stage for many of the topics discussed by Berger. The central theme of the book is clearly stated on the first page: if individuals that are likely to reproduce do not do so because of the behavior of others, then social limitations are imposed on the size of the population. Thus, Berger addresses the venerable problem of population regulation, but through a detailed analysis of the social interactions of individuals. That phenotypically variable behavior patterns are key components in behavioral ecology is receiving increasing recognition, and the data presented here further attest to the importance of this perspective. For Berger,

X-Radiographic Observations of Food Passage through Digestive Tracts of Lemon Sharks

The time required for a meal to be completely eliminated from the digestive tract of the lemon shark Negaprion brevirostris was determined X-radiographically, with barium sulfate as a contrast medium. Two food markers and X-radiography showed that initial voidance of fecal matter began 16–17 h after feeding. Alimentary tracts emptied completely within 68–82 h after food ingestion. Passage of a meal through the digestive tract took substantially longer than in most teleosts. A slow rate of food passage may contribute to the low consumption of food and slow growth that have been observed for the lemon shark.

Study of the rate of passage of food with chromium-mordanted plant cells in chickens (Gallus gallus).

Thirty broilers 8-10 weeks old were used to study the rate of food passage in chickens. Wheat bran and rice husks of three different sizes: more than 2 mm, between 1 and 1.5 mm, and less than 0.5 mm, mordanted with chromium, were used as markers. The suitability of these markers to study the rate of food passage in chickens and the possible influence of the size and hardness of the particle on the retention time was the objective of this study. Both T1, the time of first appearance of the marker, and Tm, the mean retention time, have been evaluated. Tm was a better parameter than T1 for studying transit time. Tm was longer with the biggest particles, especially with rice husk. The gizzard, with its grinding activity and pylorus, a selector of particle size, seems to be the transit regulator for solid particles in chickens. No chromium was found in the caecal contents of any case.

Influence of nutrient density on feed consumption, weight gain and gut capacity of broilers, leghorns and turkeys reared to 26 days of age

Four levels of dietary fibre and fat, in a factorial arrangement, were added to diets for 5-day-old male broilers, Leghorns and turkeys for a 21-day experimental period. Broilers gained more weight, but had a poorer feed:gain ratio than did turkeys, while the Leghorns were vastly inferior. The turkeys had a significantly higher concentration of carcass protein and lower concentration of carcass fat than did the other two species. Higher dietary fat levels markedly increased weight gain of the broilers, while the turkeys and Leghorns were little affected. Higher levels of dietary fibre reduced linearly the body weight gain of the broilers and turkeys, but only at the 30% level of inclusion was weight of the Leghorns reduced. Of the three species Leghorns had the largest gut size per unit body weight, while the broiler was significantly larger than the turkey. Dietary fat level had no effect on gizzard weight of Leghorns, while broiler gizzard weight was significantly increased and that of turkeys significantly reduced with increased fat levels. Higher dietary fibre levels increased gizzard weight for all three species. Increased dietary fat levels increased intestinal weight, while increased dietary fibre decreased intestinal weight for all three species. However, while intestinal length per unit body weight differed between species, it varied little with changes in dietary fat level. Specific weight of the diet, on a dry weight basis, decreased with the addition of both fat and fibre. Turkeys ate more volume of feed than did the broilers, even though their overall feed intake, per unit body weight, was less. This is explained by the increased intake in feed volume of the turkey with the higher fat diets. Rate of food passage was similar for the broilers and Leghorns, but was significantly faster for the turkeys.

Influence of ambient temperature on feeding activity parameters and digestive function in domestic fowls

In order to better understand the way in which domestic fowls regulate their food intake at different ambient temperatures, measurements were made of feeding activity parameters, drinking, rate of food passage, apparent digestibility and gut dimensions of immature female fowls acclimated to cool (8°C), moderate (20°C) and warm (32°C) environments. At 8°C birds had longer ( p<0.05) intervals between meals, ate larger meals, ate faster within meals and digested their food more efficiently than at 20°C. At 32°C they ate less food per day, drank more water, had a higher water/food intake ratio, ate slower within meals, had a slower rate of food passage, and had smaller proventriculi, gizzards and caeca than at 20°C. It is concluded that differences in daily food intake between temperatures are associated more closely with differences in meal size and rate of eating within meals than with differences in meal frequency. Effects of temperature on behavioural thermoregulation, drinking and rate of food passage all influence patterns of feeding activity shown.

Biology of the Green Turtle, Chelonia mydas, on an Arabian Feeding Ground

A population of Green Turtles (Chelonia mydas) from the Masirah Channel in the northern Indian Ocean is described. Aerial surveys and a mark and recapture program establish that between 1000 and 3000 turtles are present throughout the year. An analysis of stomach contents shows that these turtles feed on both seagrasses (Halophila ovalis and Halodule uninervis) and algae (Sargassum illicifolium and Chaetomorpha aerea). Standing crops of suitable turtle food are low and the mixed diet of this population is considered to be a response to low food availability. Captures of turtles by local fishermen are analyzed. The relationship of turtles on this feeding ground to nesting areas in the northern Indian Ocean are discussed and the effects of the observed dietary preferences on the productivity of the population are considered in relation to management needs. Green turtles, Chelonia mydas, spend the greater part of their adult lives feed- ing in shallow, tropical, marine situa- tions. However, detailed knowledge of their biology is largely restricted to nesting beaches where the aggregated females are accessible to study. C. mydas is unique among sea turtles in that wild adults are entirely herbivorous. Bjorn- dal (1979a, b, 1980) showed that C. my- das uses bacterial digestion to utilize cellulose, but that digestible nitrogen is a critical nutrient. In order to support effective bacterial digestion, C. mydas has slow food passage rates through the gut and is, therefore, limited in daily food intake. This may explain the slow growth rate observed in C. mydas eating fibrous natural food in the wild (Balazs, 1980; Limpus and Walter, 1980). Bjorn- dal (op. cit.) described specialized feed- ing behavior and highly efficient bac- terial digestion that may be a response to the dietary limitations on intake and growth. Comparisons of the diet of green tur-

Influence of vagotomy in domestic fowls on feeding activity, food passage, digestibility and satiety effects of two peptides

The effects of bilateral vagotomy at the level of the proventriculus, in immature female fowls (VAG), on body weight, feeding activity parameters, rate of food passage, digestibility, and satiety effects of bombesin (BBS) and cholecystokinin octapeptide (CCK8), were compared with those in sham-operated controls (SHAM). SHAM birds gained weight at a greater rate postoperatively than before their operation, whereas VAG birds did not. Daily food intake did not change significantly as a result of the operation with either SHAM or VAG birds, and the only effect on feeding activity parameters was on the length of intermeal intervals, which increased in VAG birds. Rate of passage of the layers' mash diet was slower, and its apparent digestibility lower, in VAG than in SHAM birds. Short-term suppression of food intake, following intravenous injections of BBS (10 μg/kg) or CCK8 (10 μg/kg), did not differ between SHAM and VAG birds. The different postoperative weight gains may have been a consequence of different weights of food digested, and the difference in interval length was probably due to the different rates of food passage. The results of these experiments indicate that efferent information affecting rate of passage and digestibility travels via the vagus, but that afferent information concerned with initiation and termination of meals, and with satiety effects of BBS and CCK8, does not. Instead, such afferent information may travel via the intestinal nerve, which is unique to birds.

Rate of digestion in three species of pinnipeds

Torpid bowels or an impaction obstruction significantly retards the rate of passage of digesta in an animal and can lead to serious clinical problems. In many captive animals the approximate rate of food passage is well-known, thus allowing for rapid diagnosis and treatment if an intestinal blockage occurs. Although pinnipeds are commonly kept in captivity, the rate of passage of digesta in these animals is not known. In this study, the time period that elapsed before the initial defecation of a dye-marked meal was determined for 20 pinnipeds representing three species. This initial defecation time (IDT) serves as a good indicator of the rate of passage of digesta. The mean IDTs determined for pinnipeds were very fast averaging 5 h or less. No other medium to large carnivore or omnivore has been shown to exhibit such a rapid rate of passage. The extraordinarily fast excretion rate of these animals is even more remarkable considering that their intestine to body length ratios are among the largest in the animal kingdom. It is hypothesized that the rate of passage of digesta in pinnipeds is strongly influenced by their high metabolic rate and the high water content of their digesta.

Growth Performance and Intestinal Transit Time of Rats Fed Purified and Natural Dietary Fibers

The effects of some selected purified fibers were compared to those derived from cereals or legume seeds. Rats were fed for at least 9 weeks and measurements were taken to determine feed consumption, weight gain, feed efficiency ratios (FER), protein efficiency ratios (PER), apparent protein digestibility, and rate of transit through the gastrointestinal tract. Most diets were designed to contain approximately 10% dietary fiber and 10% protein. Compared to the fiber-free diet, pectin reduced weight gain, FER, PER and apparent protein digestibility values. Cellulose, xylan and raffinose had no influence on feed intake, weight gains or FERs. However, cellulose and xylan increased PER values and the rates of food passage but decreased the apparent protein digestibility values. Feed utilization, protein digestibility and growth were similar for the wheat bran, corn bran and fiber-free diets. These cereal fibers caused the rates of transit to be significantly increased relative to the fiber-free control diet. The hull and cell-wall-fiber fractions of beans, when compared to the fiber-free diet, had little effect on feed consumption, growth, FER or PER. The cell-wall-fiber fraction reduced apparent protein digestibility and the hull fraction accelerated food passage relative to the fiber-free diet.