Why do eastern curlews Numenius madagascariensis feed on prey that lowers intake rate before migration?

Eastern curlews Numenius madagascariensis spending the nonbreeding season in eastern Australia foraged on three intertidal decapods: soldier crab Mictyris longicarpus, sentinel crab Macrophthalmus crassipes and ghost-shrimp Trypaea australiensis. Due to their ecology, these crustaceans were spatially segregated (=distributed in 'patches') and the curlews intermittently consumed more than one prey type. It was predicted that if the curlews behaved as intake rate maximizers, the time spent foraging on a particular prey (patch) would reflect relative availabilities of the prey types and thus prey-specific intake rates would be equal. During the mid-nonbreeding period (November-December), Mictyris and Macrophthalmus were primarily consumed and prey-specific intake rates were statistically indistinguishable (8.8 versus 10.1 kJ x min(-1)). Prior to migration (February), Mictyris and Trypaea were hunted and the respective intake rates were significantly different (8.9 versus 2.3 kJ x min(-1)). Time allocation to Trypaea-hunting was independent of the availability of Mictyris. Thus, consumption of Trypaea depressed the overall intake rate. Six hypotheses for consuming Trypaea before migration were examined. Five hypotheses: the possible error by the predator, prey specialization, observer overestimation of time spent hunting Trypaea, supplementary prey and the choice of higher quality prey due to a digestive bottleneck, were deemed unsatisfactory. The explanation for consumption of a low intake-rate but high quality prey (Trypaea) deemed plausible was diet optimisation by the Curlews in response to the pre-migratory modulation (decrease in size/processing capacity) of their digestive system. With a seasonal decrease in the average intake rate, the estimated intake per low tide increased from 1233 to 1508 kJ between the mid-nonbreeding and pre-migratory periods by increasing the overall time spent on the sandflats and the proportion of time spent foraging.

Lack of an osmotic constraint on intake rate of the eastern curlew Numenius madagascariensis

Rates of food intake in animals consuming abundant prey can be constrained by the rates of digestion or excretion of ingested substances, such as salt, particularly so in the animals that regularly migrate between freshwater and saltwater environments. We tested this hypothesis in a long-distance migrant shorebird, the eastern curlew Numenius madagascariensis (suborder Charadrii), foraging on intertidal decapods in eastern Australia. We predicted that if food intake rates are constrained osmotically, individuals with access to freshwater and less saline prey (FW group) would have higher rates of food and water intake than individuals with seawater-only access (SW group). Food intake rates did not differ between the FW and SW groups (0.14 g ash-free dry mass min(-1)), nor did the water influx rates (0.75 g min(-1)). Salt intake rates were lower at FW sites (19.3 versus 23.3 mg NaCl min(-1)) and overall they were similar to those of marine birds. Food intake rate in the eastern curlew appeared limited by digestive rather than by osmoregulatory capacity.

Nonbreeding Eastern Curlews Numenius madagascariensis Do Not Increase the Rate of Intake or Digestive Efficiency before Long-Distance Migration because of an Apparent Digestive Constraint

The possibility of premigratory modulation in gastric digestive performance was investigated in a long-distance migrant, the eastern curlew (Numenius madagascariensis), in eastern Australia. The rate of intake in the curlews was limited by the rate of digestion but not by food availability. It was hypothesized that before migration, eastern curlews would meet the increased energy demand by increasing energy consumption. It was predicted that (1) an increase in the rate of intake and the corresponding rate of gastric throughput would occur or (2) the gastric digestive efficiency would increase between the mid-nonbreeding and premigratory periods. Neither crude intake rate (the rate of intake calculated including inactive pauses; 0.22 g DM [grams dry mass] or 3.09 kJ min(-1)) nor the rate of gastric throughput (0.15 g DM or 2.85 kJ min(-1)) changed over time. Gastric digestive efficiency did not improve between the periods (91%) nor did the estimated overall energy assimilation efficiency (63% and 58%, respectively). It was concluded that the crustacean-dominated diet of the birds is processed at its highest rate and efficiency throughout a season. It appears that without a qualitative shift in diet, no increase in intake rate is possible. Accepting these findings at their face value poses the question of how and over what time period the eastern curlews store the nutrients necessary for the ensuing long, northward nonstop flight.

The effect of wilting and soaking Eupatorium adenophorum on its digestibility in vitro and voluntary intake by goats

An experiment was conducted to determine what effect simple treatments might have on the voluntary intake by goats in Nepal of Eupatorium adenophorum, an invasive weed that is usually only consumed by goats to a very limited extent. Samples of E. adenophorum were collected and either untreated, soaked for 2 h or wilted for 2 h before being oven dried (60 degrees C) and ground. Soaking and wilting had little effect on the chemical composition of E. adenophorum, but did increase (P=0.036) its in vitro organic matter degradability, by approximately 8%. The short-term intake rate (STIR) of treated and untreated E. adenophorum was then estimated with eight goats. Soaking time (from 2 to 24 h) was not related to STIR (r = -0.111, P=0.198), but the time E. adenophorum was left to wilt (from 2 to 48h), was positively related to STIR (r=0.521, P<0.001), with values of STIR (g dry matter/min kg goat liveweight(0.75)) being 0.405, 0.649,1.058, S.E.M. 0.088 for E. adenophorum, that had been wilted for 0, 24 and 48 h respectively (P<0.001). Liveweight change of goats and voluntary intake of E. adenophorum by goats was then estimated with 24 goats. E. adenophorum was fed either unwilted, or wilted for 24 or 48 h. It was fed as the sole forage or as a 3:1 mixture (dry matter basis) with Ficus cunia. There was a linear (P<0.001) and quadratic (P<0.01) increase in the intake of total forage and E. adenophorum with wilting time of E. adenophorum. Offering Ficus cunia increased total forage intake, but decreased E. adenophorum intake (P<0.05). After four weeks, there was virtually no change in goat liveweight and no significant difference between treatments. The results suggest that wilting E adenophorum for 24 h could increase its intake by goats, and thereby increase its usefulness, as a potential source of forage in the dry season of Nepal, when forage scarcity is a common constraint to livestock production. (C) 2007 Elsevier B.V. All rights reserved.

Intake rates and the functional response in shorebirds (Charadriiformes) eating macro-invertebrates

As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an individual-based model of shorebird Charadriiformes populations, we attempted this for shorebirds eating macro-invertebrates. Intake rate is measured as the ash-free dry mass (AFDM) per second of active foraging; i.e. excluding time spent on digestive pauses and other activities, such as preening. The present and previous studies show that the general shape of the functional response in shorebirds eating approximately the same size of prey across the full range of prey density is a decelerating rise to a plateau, thus approximating the Holling type 11 ('disc equation') formulation. But field studies confirmed that the asymptote was not set by handling time, as assumed by the disc equation, because only about half the foraging time was spent in successfully or unsuccessfully attacking and handling prey, the rest being devoted to searching. A review of 30 functional responses showed that intake rate in free-living shorebirds varied independently of prey density over a wide range, with the asymptote being reached at very low prey densities (< 150/m(-2)). Accordingly, most of the many studies of shorebird intake rate have probably been conducted at or near the asymptote of the functional response, suggesting that equations that predict intake rate should also predict the asymptote. A multivariate analysis of 468 'spot' estimates of intake rates from 26 shorebirds identified ten variables, representing prey and shorebird characteristics, that accounted for 81 % of the variance in logarithm-transformed intake rate. But four-variables accounted for almost as much (77.3 %), these being bird size, prey size, whether the bird was an oystercatcher Haematopus ostralegus eating mussels Mytilus edulis, or breeding. The four variable equation under-predicted, on average, the observed 30 estimates of the asymptote by 11.6%, but this discrepancy was reduced to 0.2% when two suspect estimates from one early study in the 1960s were removed. The equation therefore predicted the observed asymptote very successfully in 93 % of cases. We conclude that the asymptote can be reliably predicted from just four easily measured variables. Indeed, if the birds are not breeding and are not oystercatchers eating mussels, reliable predictions can be obtained using just two variables, bird and prey sizes. A multivariate analysis of 23 estimates of the half-asymptote constant suggested they were smaller when prey were small but greater when the birds were large, especially in oystercatchers. The resulting equation could be used to predict the half-asymptote constant, but its predictive power has yet to be tested. As well as predicting the asymptote of the functional response, the equations will enable research workers engaged in many areas of shorebird ecology and behaviour to estimate intake rate without the need for conventional time-consuming field studies, including species for which it has not yet proved possible to measure intake rate in the field.

Effects of dietary level of protein, lysine and methionine and strain of bird on production and egg yolk cholesterol

The effects of dietary level of protein (151, 181 g/kg), lysine (nil, 10g L-lysine hydrochloride/kg) and methionine (nil, 5g DL-methionine/kg) on the production performance and egg yolk cholesterol of two strains of birds were studied for 12 weeks. Birds fed on the high protein diet had higher body weight gain, feed conversion ratio (FCR), rate of lay, egg weight and mass and yolk weight and mass. A high lysine diet decreased feed intake and improved FCR. High dietary level of methionine increased egg yolk cholesterol. There were differences between strains of laying bird in feed intake, rate of lay, egg and yolk weights and egg cholesterol content. It is concluded that strain of bird and dietary level of protein and lysine influenced the production performance of birds. Whilst, egg yolk cholesterol was not reduced by any of the factors studied.

Depletion of benthic invertebrates by bar-tailed godwits Limosa lapponica in a subtropical estuary

This study (1) investigated functional (capture rate, foraging success) and numerical (density) responses of bar-tailed godwits Limosa lapponica to an experimental decrease in densities of their prey, and (2) estimated seasonal depletion of the stock of their main prey, the mictyrid crab Mictyris longicarpus, in a subtropical estuary. It was predicted that if intake rates of the godwits are in the vicinity of the gradient section of a functional response curve, i.e. are directly determined by prey density, they will respond rapidly to experimental reduction in the density of their prey. Bar-tailed godwits did respond rapidly, both functionally and numerically, to a decrease in the density of M longicarpus, indicating that their intake rate was limited by food availability. The estimated seasonal depletion of the stocks of Mictyris by the godwits was 88 % of the initial standing stock. Despite the virtual disappearance of Mictyris from sediment samples through the course of a non-breeding season, local densities of godwits did not change between October and March, implying that adequate rates of intake could be maintained throughout their residence period.

Dieta de Traupíneos (Passeriformes, Emberizidae) no Parque Estadual do Ibitipoca, Minas Gerais, Brasil

Eleven species of tanagers in Ibitipoca State Park, Minas Gerais, southeastern Brazil, were studied for 12 months and the birds diet was described. Fruits of 52 plant species were the main item consumed for all tanagers, representing 59.70% of all items in 1330 events, although different proportions in the use of this resource have been found among the bird species. The main plant families found were Myrtaceae with eight species accounting for 22.29% (n=177), and Melastomataceae with seven species accounting for 22.29% (n=177) of fruit intake. The most frequent plant species in the diet was Cecropia glaziovi Snethl. (Cecropiaceae), which made up 17.76% (n=141) of fruit intake of all species of tanagers. Arthropod consumption came second with 22.63% (n=301), but flowers, leaves, nectar, food remains left by tourists and galls were also represented. Several environmental features influenced diet composition. An Asteraceae, Vanillosmopsis erythropappa Schultz, very common in the park, was important for some birds as its flowers attracted arthropods and its branches and leaves were used as a substrate for insectivory. Fruit intake rate, some bird-plant interaction and features of food-handling were also discussed, pointing to the importance of these birds for the structure of the heterogeneous local landscape, possibly through the spread of seeds of different plant species.

Noise, predation risk compensation and vigilance in the chaffinch Fringilla coelebs

Background noise should in theory hinder detection of auditory cues associated with approaching danger. We tested whether foraging chaffinches Fringilla coelebs responded to background noise by increasing vigilance, and examined whether this was explained by predation risk compensation or by a novel stimulus hypothesis. The former predicts that only inter-scan interval should be modified in the presence of background noise, not vigilance levels generally. This is because noise hampers auditory cue detection and increases perceived predation risk primarily when in the head-down position, and also because previous tests have shown that only interscan interval is correlated with predator detection ability in this system. Chaffinches only modified interscan interval supporting this hypothesis. At the same time they made significantly fewer pecks when feeding during the background noise treatment and so the increased vigilance led to a reduction in intake rate, suggesting that compensating for the increased predation risk could indirectly lead to a fitness cost. Finally, the novel stimulus hypothesis predicts that chaffinches should habituate to the noise, which did not occur within a trial or over 5 subsequent trials. We conclude that auditory cues may be an important component of the trade-off between vigilance and feeding, and discuss possible implications for anti-predation theory and ecological processes

The Incidence of Dysphagia in Patients Receiving Cerebral Reperfusion Therapy Poststroke

Background: The high prevalence of dysphagia after stroke leads to increased mortality, and cerebral reperfusion therapy has been effective in reducing neurologic deficits. The aim of this study was to investigate the severity and evolution of dysphagia and the occurrence of pneumonia in patients submitted to cerebral reperfusion therapy. Methods: Seventy ischemic stroke patients were evaluated. Of these, 35 patients (group 1) were submitted to cerebral reperfusion therapy and 35 (group 2) did not receive thrombolytic treatment. The following were evaluated: severity of dysphagia by means of videofluoroscopy, evolution of oral intake rate by means of the Functional Oral Intake Scale, and the occurrence of pneumonia by international protocol. The relation between the severity of dysphagia and the occurrence of pneumonia with the treatment was evaluated through the chi-square test; the daily oral intake rate and its relation to the treatment were assessed by the Mann-Whitney test and considered significant if P is less than .05. Results: The moderate and severe degrees of dysphagia were more frequent (P = .013) among the patients who were not submitted to cerebral reperfusion therapy. The daily oral intake evolved independently of the treatment type, without statistical significance when compared between the groups, whereas pneumonia occurred more frequently in group 2 (28%) in relation to group 1 (11%) and was associated with the worst degrees of dysphagia (P = .045). Conclusions: We can conclude that there is improvement in the oral intake rate in both groups, with lower severity of dysphagia and occurrence of pneumonia in ischemic stroke patients submitted to cerebral reperfusion therapy. (C) 2014 by National Stroke Association

(Table 2) Protein and fibre content of important food plants of barnacle geese (Branta leucopsis) in Adventdalen

Goose grazing on arctic tundra vegetation has shown both positive and negative effects on subsequent foraging conditions. To understand the potential of a density-dependent feedback on herbivore population size, the relation between grazing pressure and future foraging conditions is essential. We studied the effect of increasing grazing pressure of barnacle geese (Branta leucopsis) on Spitsbergen. During the establishment of a breeding colony in the period 1992-2004, the proportion of graminoids decreased in the diet of wild geese, while the percentage of mosses increased. Grazing trials with captive geese in an unexploited area showed a similar shift in diet composition. High-quality food plants were depleted within years and over years. Intake rate declined too and as consequence, metabolisable energy intake rate (MEIR) decreased rapidly with increasing grazing pressure. During three successive years of experimental grazing, MEIR decreased at all levels of grazing pressure and declined below minimal energetic requirements when grazing exceeded natural levels of grazing pressure. This suggests that foraging conditions rapidly decline with increasing grazing pressure in these low-productive habitats. The potential for density-dependent feedbacks on local population increase is discussed.

Correlations of circulating peptide YY and ghrelin with body weight, rate of weight gain, and time required to achieve the recommended daily intake in preterm infants

The objective was to elucidate the relationships between serum concentrations of the gut hormone peptide YY (PYY) and ghrelin and growth development in infants for potential application to the clinical observation index. Serum concentrations of PYY and ghrelin were measured using radioimmunoassay from samples collected at the clinic. For each patient, gestational age, birth weight, time required to return to birth weight, rate of weight gain, time required to achieve recommended daily intake (RDI) standards, time required for full-gastric feeding, duration of hospitalization, and time of administration of total parenteral nutrition were recorded. Serum PYY and ghrelin concentrations were significantly higher in the preterm group (N = 20) than in the full-term group (N = 20; P < 0.01). Within the preterm infant group, the serum concentrations of PYY and ghrelin on postnatal day (PND) 7 (ghrelin = 1485.38 ± 409.24; PYY = 812.37 ± 153.77 ng/L) were significantly higher than on PND 1 (ghrelin = 956.85 ± 223.09; PYY = 545.27 ± 204.51 ng/L) or PND 3 (ghrelin = 1108.44 ± 351.36; PYY = 628.96 ± 235.63 ng/L; P < 0.01). Both serum PYY and ghrelin concentrations were negatively correlated with body weight, and the degree of correlation varied with age. Serum ghrelin concentration correlated negatively with birth weight and positively with the time required to achieve RDI (P < 0.05). In conclusion, serum PYY and ghrelin concentrations reflect a negative energy balance, predict postnatal growth, and enable compensation. Further studies are required to elucidate the precise concentration and roles of PYY and ghrelin in newborns and to determine the usefulness of measuring these hormones in clinical practice.

Effect of feeding fat or intrajugular infusion of glucagon-like peptide-1 and cholecystokinin on dry matter intake, digestibility, and digesta rate of passage in growing wethers

A cause and effect relationship between glucagon-like peptide 1 (7, 36) amide (GLP-1) and cholecystokinin (CCK) and DMI regulation has not been established in ruminants. Three randomized complete block experiments were conducted to determine the effect of feeding fat or infusing GLP-1 or CCK intravenously on DMI, nutrient digestibility, and Cr rate of passage (using Cr(2)O(3) as a marker) in wethers. A total of 18 Targhee × Hampshire wethers (36.5 ± 2.5 kg of BW) were used, and each experiment consisted of four 21-d periods (14 d for adaptation and 7 d for infusion and sampling). Wethers allotted to the control treatments served as the controls for all 3 experiments; experiments were performed simultaneously. The basal diet was 60% concentrate and 40% forage. In Exp. 1, treatments were the control (0% added fat) and addition of 4 or 6% Ca salts of palm oil fatty acids (DM basis). Treatments in Exp. 2 and 3 were the control and 3 jugular vein infusion dosages of GLP-1 (0.052, 0.103, or 0.155 µg•kg of BW(-1)•d(-1)) or CCK (0.069, 0.138, or 0.207 µg•kg of BW(-1)•d(-1)), respectively. Increases in plasma GLP-1 and CCK concentrations during hormone infusions were comparable with increases observed when increasing amounts of fat were fed. Feeding fat and infusion of GLP-1 tended (linear, P = 0.12; quadratic, P = 0.13) to decrease DMI. Infusion of CCK did not affect (P > 0.21) DMI. Retention time of Cr in the total gastrointestinal tract decreased (linear, P < 0.01) when fat was fed, but was not affected by GLP-1 or CCK infusion. In conclusion, jugular vein infusion produced similar plasma CCK and GLP-1 concentrations as observed when fat was fed. The effects of feeding fat on DMI may be partially regulated by plasma concentration of GLP-1, but are not likely due solely to changes in a single hormone concentration.

CO intake fraction and city ventilation rate in Hong Kong

Given the background of serious urban pollution in Hong Kong, the intake fraction (iF) of carbon monoxide due to mobile vehicles in urban area of Hong Kong is investigated and estimated to be 600 per million, much higher than those in US urban areas, Helsinki and even Beijing, indicating the high exposure level to urban pollutants in Hong Kong. The dependence of iF to the metrological factors is also discussed. Easterly and northerly winds contribute most to the total iF value. A new method of predicting ventilation rate for a city based on iF concept is proposed. City ventilation rates for different cities are calculated and compared. It is found that Hong Kong has to face the fact that it has the lowest ventilation rate and ACH.