Daytime Feeding Research Articles

한강에서 월동하는 수금류의 서식지로서 중랑천의 중요성

도심 하천은 야생조수에게 물의 공급원이며 서식지로서 도시 생태계를 유지시키는 중요한 역할을 담당한다. 본 조사는 서울의 주요 하천 중 하나인 중랑천에서 월동 수금류의 서식지 이용 실태를 알아보고자 수행되었다. 개체군 변동에 대한 분석은 1997년 12월부터 1998년 3월까지 수행된 센서스와 1999년부터 2004년까지의 환경부와 국립환경연구원이 실시한 겨울철 조류 동시 센서스 자료를 참고로 하였으며 개체군의 서식지 이용에 대한 조사는 쇠오리의 월동 행동 관찰을 통해 수행되었다 중랑천에서 월동하는 조류는 최소 3,004개체에서 최대 8,237개체로 주로 수면성 오리류였으며 잠수성 오리류도 상당수가 도래하였다. 연간 개체군 변동은 수면성 오리류보다는 잠수성 오리류에서 크게 나타났고 전체 수금류 개체군은 1월말과 2월말에 가장 많은 수가 도래하였다. 시간대별 개체군 변동을 보면 수금류의 개체수는 오후로 갈수록 증가하여 특히 일몰 후에는 한강 본류로부터 유입되는 개체가 크게 증가하는 것으로 보아 이 지역은 수금류의 주간 취식지뿐만 아니라 야간취식지로서 중요하게 이용되는 것으로 보인다. 잠수성 오리인 비오리와 댕기흰죽지는 낮은 기온과 높은 풍속일 때 개체수가 증가하는 것으로 보아 날씨에 따라 중랑천을 휴식지로 이용하는 것으로 보인다. Urban stream is an important place supporting urban ecosystem. This study was carried out to clarify the role of Jungrangchun for wintering waterbirds in Seoul. We monitored the fluctuation of waterbirds population using our census data (1997/98 winter) and pervious census data (the Ministry of Environment and National Institute of Environmental Research <TEX>$1999{\sim}2004$</TEX>). Wintering behaviours of common teals (Anas crecca) were also observed to understand the habitat use of waterbirds in this area. As a result of this, Jungrangchun was an important place to support <TEX>$3,004\sim8,237$</TEX> wintering birds, mainly dabbling ducks and diving ducks. The population of diving ducks showed high annual fluctuation whilst the population of dabbling ducks regularly used this area every year The maximum number of waterbirds foraged and rested in late January and late February. In daily use, the number of waterbirds increased on afternoon and rapidly increased after sunset. It is assumed that waterbirds used this area not only as a nocturnal feeding site but also daytime feeding site. Thus, this result suggest that Jungrangchun is important for not only the daily use but also the nocturnal use of wintering waterbirds. The number of diving ducks was increased with low temperature and high wind speed. Therefore, this area was also a shelter of diving ducks on chilly and windy day.

Temporal and size‐related changes in the frequency of empty stomachs in smelt

The frequency of empty stomachs (FES) of 3290 smelt Osmerus eperlanus was analysed during winter and two growing seasons. Variations in FES showed that smelt is a daytime feeder and feeding activity is low during the hours of darkness and also during the winter under ice cover. The results suggested further that the diet shifts of smelt are not permanent until the onset of piscivory.

P.4.045 Chronopharmacology of drugsimproving cognitive brain functions

Circadian rhythms (Nobel prize for Medicine 2017) regulate, under action of biological clocks located both at the level of central nervous system and inside peripheral cells, several daily activities, embracing sleep, feeding times, energy metabolism, endocrine and immune functions with related pathological conditions, including rheumatoid arthritis (RA).In RA the circadian rhythms impact on cellular functions, involving night synthesis and release of pro-inflammatory cytokines and chemokines, cell migration to inflamed tissues, phagocytosis, proliferative cell response and all are peaking at late night. In chronic inflammatory conditions such as RA, the amplitude of the circadian rhythm of the anti-inflammatory endogenous cortisol availability is not increased as expected and requested, which indicate a reduced night cortisol secretion under the adrenal chronic stress induced by the disease. Therefore, the prevention/treatment of the immune cell night hyperactivity, with related flare of cytokine synthesis and morning RA clinical symptoms, has been shown more effective when the availability of the exogenous glucocorticoids is obtained in the middle of the night (night release). The impressive positive results observed in RA patients treated with modified-night release prednisone with a low-dose chronotherapy, seem applicable even for other agents such as conventional NSAIDs and DMARDs, including the positive experimental and clinical results obtained by the night time daily administration of methotrexate. Interestingly, a very recent study showed that methotrexate upregulates important cell circadian genes, resulting in induction of apoptosis in synovial fibroblasts. The link between the circadian rhythms of the disease and the chronotherapy of RA is promising.

Larval feeding habits of Diaphus theta, Protomyctophum thompsoni, and Tarletonbeania taylori (Pisces: Myctophidae) in the transition region of the western North Pacific

We examined the larval feeding habits of the 3 dominant myctophids, Diaphus theta, Protomyctophum thompsoni, and Tarletonbeania taylori, in the transition region of the western North Pacific. Feeding incidence for D. theta and T. taylori larvae was higher during the day than at night (mean: 70.7 to 84.4% vs. 2.2 to 4.1%), indicating that they are daytime visual feeders. Larvae of P. thompsoni were also visual feeders, with a daytime feeding incidence of 83.0%. The proportion of nighttime feeding in P. thompsoni gradually increased with development, which suggests faster lar- val adaptation of this non-migrant species to the poor light conditions in the mesopelagic zone. D. theta larvae ≤7.9 mm in body length (BL) fed mainly on copepod nauplii, which were replaced by calanoid copepodites and Oithona spp. in larvae ≥8.0 mm BL. The most important prey for smaller P. thompsoni and T. taylori larvae ≤7.9 mm BL were nauplii and Oithona spp., which were replaced by calanoid copepodites and ostracods in P. thompsoni and copepod eggs in T. taylori with increased development. Competition for prey among the larvae of these 3 myctophids was mostly avoided because of diet and habitat-depth segregation. Interspecific comparisons of feeding habits among the 3 species, in addition to larvae of 3 other myctophids found in the study area, suggested that their feeding strategies were associated with mouth size, i.e. larvae with larger mouths tended to take larger prey rather than a large number of smaller prey. This interspecific difference in feeding strategy is reflected in the diverse morphological characters of myctophid fish larvae.

Enhanced running wheel activity of both Mch1r- and Pmch-deficient mice

Mch1r-deficient ( Mch1r −/−) mice are hyperphagic, hyperactive, lean, and resistant to diet-induced obesity. To examine whether the MCH1R is involved in regulating activity-based energy expenditure, we investigated voluntary wheel running (WR) activity of wild-type (WT) and Mch1r −/− mice basally, in response to diets with different caloric density and with different feeding schedules. We also evaluated WR activity of mice with ablation of the prepro-MCH gene ( Pmch −/− mice). Dark cycle WR activity of Mch1r −/− mice fed low fat (LF) chow was increased significantly relative to WT mice. Transition to moderate high-fat (MHF) diet was associated with an increase in nocturnal WR activity in both genotypes. Both Mch1r −/− and WT mice exhibited food anticipatory activity (FAA) before the daily scheduled feeding time, indicating that MCH1R is not required for FAA. Naloxone (3 mg/kg, i.p.) suppressed WR activity of both genotypes, suggesting opioid regulation of locomotor activity. WR increased nocturnal dynorphin mRNA levels in Mch1r −/− brain. Importantly, Pmch-deficient mice had significantly enhanced WR activity relative to WT controls. These results suggest that endogenous MCH plays an inhibitory role in regulating locomotor activity. In summary, we demonstrated enhanced WR activities in mice lacking either MCH or its cognate receptor.

Seasonal variations in the activity budget of Japanese macaques in the coniferous forest of Yakushima: effects of food and temperature.

Seasonal variations in the activity budget of Japanese macaques in the coniferous forest of Yakushima were studied over the course of 1 year. On an annual basis, they spent 38% of the daytime feeding, 16% traveling, 14% in social interactions, and 32% engaged in resting. The effects of temperature and food-related factors (i.e., food distribution, feeding speed, and food abundance) on the seasonal variations of activity budget were examined by stepwise multiple regression analysis. When the temperature was low, the macaques decreased traveling and feeding time, in accordance with the prediction that endothermal animals save energy under severe thermoregulatory cost. When the feeding speed of available foods was slow, they spent more time feeding. When high-quality foods were abundant, they decreased feeding time. These macaques did not respond to fluctuations in food distribution. The present results indicate the importance of temperature, in addition to food-related factors, as a determinant of activity budgets.

A method of food supplementation for ground-foraging insectivorous songbirds

Food supplementation can be an important experimental technique in studies of avian reproductive ecology, energetics, and parental care. We developed a method of food supplementation suitable for ground-foraging insectivorous passerines and tested it on Ovenbird (Seiurus aurocapilla) and Wood Thrushes (Hylocichla mustelina). We provided mealworms at feeding stations made of plastic transparency film covered with a thin layer of green moss. Feeding stations were placed on the ground or on logs or boulders in the vicinity of nests. Direct and indirect evidence suggested that 92% of breeding Ovenbirds and 79% of breeding Wood Thrushes used supplemental food. The impact of non-target consumers was not significant: they were observed eating mealworms at approximately one-third of our food-supplemented nests. However, diurnal non-target consumers were only detected on a single occasion for each species, and nocturnal consumers fed on small amounts of mealworms left after daytime feeding experiments. This method proved very effective for Ovenbirds and Wood Thrushes, and it may be applicable to other ground-foraging insectivorous passerines.

Rhinopithecus bieti at Tacheng, Yunnan: Diet and Daytime Activities

We collected data on diet and activity budget in a group of Rhinopithecus bieti at Tacheng (99°18′E, 27° 36'N, between 2,700–3,700 m asl), Yunnan, from March 1999 to December 2000. We mainly recorded species-parts eaten with feeding scores from scanning state behaviors of one-male units in tree-crowns. We also conducted microscopic analysis of feces collected monthly. The subjects consumed 59 plant species, belonging to 42 genera in 28 families, of which 90 species-parts were distributed as follows: 21 in Winter, 38 in spring, 39 in Summer, 47 in autumn. Conversely, the group annually spent, on average, 35% of daytime feeding, 33% resting, 15% moving, and 13% in social activities. Seasonal changes are apparent in daytime budget and food item-related feeding time in tree-crowns, food remains in feces, and the number of species-parts eaten. Correlations within and between food items and time budget clearly indicate maximization of foraging effectiveness and minimization of energy expenditure. In consideration of reports from northern and southern groups, that which underlay the specific adaptation to the habitat appeared to be similar to those of other colobines. Thus, the ultimate factors for survival of the species are more hopeful than expected.

Feeding is not a more potent Zeitgeber than the light-dark cycle in Drosophila.

Daily scheduled feeding is a potent Zeitgeber that elicits anticipatory activity in mammals. Recent studies have revealed that daytime feeding of nocturnal laboratory rodents completely inverts the phase of circadian gene expression in peripheral tissues such as heart, liver and kidney, independently of environmental light cycles. To investigate whether feeding is a potent time cue for Drosophila, we examined the behavioral activity rhythm and peripheral expression profile of clock genes in Drosophila under 12 h of night-time restricted feeding. We found that flies could not exhibit food-anticipatory activity rhythms under restricted feeding. Expression profiles of the clock genes period and timeless were not affected by either the phase or the amplitude in the periphery. These results suggest that feeding is not a more potent Zeitgeber than the light/dark cycle at either the individual behavioral level or at the peripheral molecular clock levels in Drosophila.

Daily Changes of Plasma Corticosterone by an 8-h Daytime Feeding Occur Without Body Weight Loss or Severe Food Restriction in the Rat

Different studies have reported that daytime feeding entrains the circadian rhythm of corticosterone secretion in rats. However, it remained unclear whether calorie restriction or daytime feeding access have an effect. The aim of our study is to evaluate the effect of an 8-h daytime feeding access on the circadian rhythm of plasma corticosterone. Eleven adult male Wistar rats were assigned to two different conditions of access to food: ad lib feeding for one week and daytime feeding for the following two weeks. On the 7th, 14th and 21st day, blood samples were collected every 4 h from 08:00 to 04:00. Food intake and body weight were recorded daily. During daytime feeding, rats ingested 88% of the amount of food ingested over 24 h in the ad lib feeding period. However, body weight increased significantly from the first day to the end of experiment. Peak plasma corticosterone was 12 h shifted during daytime feeding period compared to the ad lib condition. This study showed that an 8-h daytime feeding entrained the circadian rhythm of plasma corticosterone without body weight loss or severe food restriction.

Chimpanzee diet and habitat selection in the Budongo Forest Reserve, Uganda

Between June 2000 and August 2001 observations were made on food types, plant species and parts consumed by chimpanzee in relation to various habitats in the Budongo Forest Reserve (BFR), Uganda. Factors influencing their occurrence as well as their activity patterns were also assessed. The chimpanzees of the BFR spent 80% of their daytime feeding and their diet comprised 56 plants species of which 94% were trees. Chimpanzees spent most of their feeding time on B. papyrifera, Ficus sur, Ficus mucuso, Ficus exasperata and Ficus variifolia. Chimpanzees fed mostly on fruits (71%), favouring ripe ones, and young leaves (16%). Factors positively influencing occurrence of chimpanzees included habitat types (logged area and forest edge), plant types (trees), food types (fruits), fruit maturity (ripe fruits), and fruit quantity. Logged area and forest edge provided 76% of the chimpanzee food but are also the habitats with the highest human interference, e.g. logging and agriculture encroachment. Past forest management plans did not consider chimpanzee food trees; most were considered weeds and killed with aboricides. We conclude that the long-term survival of chimpanzees of the BFR requires implementation of management plans based on conservation of food tree species.

Gluttony in migratory waders – unprecedented energy assimilation rates in vertebrates

Maximum energy assimilation rate has been implicated as a constraint on maximal sustained energy expenditure, on biomass production, and in various behavioural and life history models. Data on the upper limit to energy assimilation rate are scarce, and the factors that set the limit remain poorly known. We studied migratory waders in captivity, given unlimited food supply around the clock. Many of these waders assimilated energy at rates of seven to ten times basal metabolism, exceeding maximum rates reported for vertebrates during periods of high energy demand, for example during reproduction and in extreme cold. One factor allowing the high energy assimilation rates may be that much of the assimilated energy is stored and not concomitantly expended by muscles or other organs. The remarkable digestive capacity in waders is probably an adaptation to long and rapid migrations, putting a premium on high energy deposition rates. The upper limit to daily energy assimilation in vertebrates is clearly higher than hitherto believed, and food availability, total daily feeding time and, possibly, the fate of assimilated energy may be important factors to take into account when estimating limits to energy budgets in animals.

Observations on the Nocturnal Activity and Feeding Behavior of Anguilla japonica Glass Eels Under Laboratory Conditions

Glass eels of the temperate anguillid species, Anguilla japonica, clearly showed a nocturnal activity rhythm under laboratory conditions. Light-dark cycle was a determinant factor affecting their photonegative behavior, nocturnal locomotor activity, and feeding behavior. Under natural light conditions, glass eels remained in shelters with little daytime feeding, but came out to forage during darkness. They moved and foraged actively in the following dark, and then their activity gradually declined possibly because of food satiation. They finally buried in the sand or stayed in tubes immediately after the lights came on. Under constant light, glass eels often came out of the shelters to forage in the lights but spent little time moving outside the shelters (e.g. swimming or crawling on the sand). Glass eels took shelter to avoid light and preferred tubes to sand for shelter possibly because tubes were much easier for them to take refuge in than sand. Feeding and locomotor activities of the glass eels were nocturnal and well synchronized. They appeared to depend on olfaction rather than vision to detect and capture prey in darkness. Feeding was the driving force for glass eels to come out of sand under constant light. However, in the dark, some glass eels swam or crept actively on sand even when they were fully fed. The lunar cycles of activity rhythms of glass eels that have been observed in some estuarine areas were not detected under these laboratory conditions.

Peripheral circadian oscillators in mammals: time and food.

Peripheral cells from mammalian tissues, while perfectly capable of circadian rhythm generation, are not light sensitive and thus have to be entrained by nonphotic cues. Feeding time is the dominant zeitgeber for peripheral mammalian clocks: Daytime feeding of nocturnal laboratory rodents completely inverts the phase of circadian gene expression in many tissues, including liver, heart, kidney, and pancreas, but it has no effect on the SCN pacemaker. It is thus plausible that in intact animals, the SCN synchronizes peripheral docks primarily through temporal feeding patterns that are imposed through behavioral rest-activity cycles. In addition, body temperature rhythms, which are themselves dependent on both feeding patterns and rest-activity cycles, can sustain circadian, clock gene activity in vivo and in vitro. The SCN may also influence the phase of rhythmic gene expression in peripheral tissues through direct chemical pathways. In fact, many chemical signals induce circadian gene expression in tissue culture cells. Some of these have been shown to elicit phase shifts when injected into intact animals and are thus candidates for physiologically relevant timing cues. While the response of the SCN to light is strictly gated to respond only during the night, peripheral oscillators can be chemically phase shifted throughout the day. For example, injection of dexamethasone, a glucocorticoid receptor agonist, resets the phase of circadian liver gene expression during the entire 24-h day. Given the bewildering array of agents capable of influencing peripheral clocks, the identification of physiologically relevant agents used by the SCN to synchronize peripheral clocks will clearly be an arduous undertaking. Nevertheless, we feel that experimental systems by which this enticing problem can be tackled are now at hand.

Daytime activity budgets of feral goats (Capra hircus) on the Isle of Rum: influence of season, age, and sex

The activity budgets of feral goats (Capra hircus) on the Isle of Rum, northwest Scotland, were studied from January to December in 1981 and from May to November in 2000. We investigated differences in activity patterns in relation to season, time of day, and age–sex classes of goats, and their possible causes. Since the goats spent the night sleeping (or resting) in caves or other sheltered sites, only diurnal activity budgets were considered. Activity patterns were very similar between the two study periods (from May to November). All age–sex classes of feral goats spent most of the daytime feeding in both years, especially during autumn and winter. Feral goats increased the percentage of daytime that they spent feeding and decreased their resting time from summer to autumn–winter in response to the decrease in available day length and, possibly, the decrease in forage quality and biomass. Feral goats on Rum had two or three daily peaks of feeding in summer, but showed no obvious daily feeding peaks in winter, although their percentage of feeding time remained relatively high throughout the daytime in winter. No significant differences in general activity budgets between adult males and females were found, but yearlings were found to spend more time feeding than adults and kids. Adult males spent more time in social activities than did other age–sex classes, and adult males sharply decreased the percentage of daytime that they spent feeding during rutting periods, which may have contributed to their higher mortality over the subsequent autumn and winter.

Effect of Feeding Schedule on Ammonia Emission from Individual and Group-housing Systems for Sows

The effect of feeding schedule on ammonia emission from housing systems for sows was studied. The hypothesis was that changing the feeding schedule would change the diurnal pattern of the ammonia emission and that daytime feeding would cause more ammonia to be emitted from the manure compared to evening feeding. The experimental units were an individual housing system with 64 dry sows in stalls (system A) and two group-housing systems: system B with 62 dry sows and feeding stalls and system C with 65 dry sows and electronic sow feeders (ESFs). In systems A and B, the sows were fed simultaneously twice daily. In system C, the sows were fed sequentially once a day. During feeding schedule 1, feeding times in systems A and B were 7:30 and 15:30 h, in system C feed was available from 15:30 h on. During schedule 2, feeding times in systems A and B were 7:30 and 21:30 h, in system C food was available from 7:30 h on. Ammonia emission, indoor temperature and animal activity were measured and the data were analysed considering autocorrelations with a time-series model. The values for the coefficients of determinations R 2 of the models explaining ammonia emission by indoor temperature and animal activity were 48% for system A, 66% for system B and 64% for system C. In all three systems, the diurnal patterns of the indoor temperature, animal activity and ammonia emission changed considerably with the feeding schedule. Average ammonia emissions per sow for feeding schedules 1 and 2 were, respectively, 0·71 and 0·68 g h −1 (probability P=0·23) from system A, 0·60 and 0·61 g h −1 ( P=0·75) from system B and 0·69 and 0·76 g h −1 ( P<0·01) from system C. It can be concluded that changing the feeding schedule alters the diurnal pattern of the ammonia emission, but if the animals are fed simultaneously, changing the feeding time does not affect the total amount of ammonia emitted. However, with the animals fed sequentially, the ammonia emission falls by 10% if the feeding starts in the afternoon instead of in the morning.

The addition of external water to fresh grass does not affect dry matter intake, feeding behaviour and rumen characteristics in dairy cows

Fresh grass is often a fodder of high nutritive value for ruminants, but its intake is limited in spite of its high digestibility. The high water content of fresh grass could limit grass DM intake by cows. The effect of external water on intake, feeding behaviour and rumen fill was studied in dairy cows fed indoors with fresh perennial ryegrass offered ad libitum. Three treatments were compared: fresh grass as harvested (C: control); C with water added to the grass (SW: surface water) and C with perfusion of water in the rumen after each distribution (PW: perfused water). Grass was offered to cows at 14:00 h, 19:00 h on each day and 07:00 h the following morning. Free access was given to drinking water. In treatment SW, the DM content of the offered grass was reduced from 161 to 117 g·kg -1 on a fresh basis (P < 0.02) without changing the chemical composition of the grass on a DM basis. Compared to C and PW, the fresh matter intake and its rate of intake increased in SW (+ 36 and 39%, respectively), but the grass DM intake (16.4 kg DM·day -1 ), the rate of DM intake (35.3 g DM·min -1 ), the daily eating time (468 min) and rumination time (515 min) were not modi- fied. Perfusion of water into the rumen did not affect intake or feeding behaviour. The weight of the rumen contents (150 kg) and their DM content (115 g·kg -1 fresh matter), rumen fluid osmolality, as well as proportions of free water and bound water and turnover rate were not modified by the treat- ments. In conclusion, for dairy cows fed on grass, important inputs of external water do not affect feeding behaviour, rumen fill nor grass DM intake. dairy cows / fresh grass / surface water / intake / behaviour / rumen fill

Individual rainbow trout can learn and anticipate multiple daily feeding times

The present study was conducted to investigate whether individual rainbow trout Oncorhynchus mykiss can simultaneously anticipate two daily meals, and to evaluate the influence of time‐restricted feeding schedules and light‐dark (L:D) cycles on the timing of self‐feeding activity. Individual rainbow trout were capable of anticipating not only a single meal but also two daily meals scheduled at different times; the duration of anticipation was short and precise. This seems to be the first convincing evidence to show that a single fish can simultaneously anticipate two daily meals. Change in the onset and cessation of light did not affect the duration of food‐anticipatory activity, although it led to shift the phases of the light‐related self‐feeding activity. Moreover, under constant light and ad lib feeding conditions, only one band of rhythmic activity was observed in individual rainbow trout that had previously developed food‐anticipatory activity to each of the two daily meals.

Individual rainbow trout can learn and anticipate multiple daily feeding times

Individual rainbow trout can learn and anticipate multiple daily feeding times

Blood glucose concentrations during breeding in Short-tailed Shearwaters

Blood glucose concentration was measured in breeding adult and non-breeding immature short-tailed shearwaters (Puffinus tenuirostris) at key stages during the breeding cycle on Phillip Island, Victoria. The species’ diet has a low carbohydrate content, but its mean whole blood glucose level of ∼14 mM L−1 was comparatively high; however, this may partly have resulted from the procedure of sampling birds relatively soon after they returned to the colony at night after daytime feeding. Mean whole blood glucose level was significantly, but not dramatically, higher (by about 3 mM) during the incubation stage than at other times during breeding. This pattern was not related to breeding energetics, because it was exhibited by both age-classes. It may have reflected systematic variation in the recent feeding history of the sampled birds over the breeding season. Coefficients of variation in whole blood glucose concentration within samples obtained across the breeding cycle ranged from 13.7 to 20.8%. This level of variation is a little higher than that observed during the fasting—feeding cycle of other bird species, but might be expected in a species that exploits patchily dispersed food resources.