Daily rhythms of locomotor and demand-feeding activities in Schizothorax pelzami (Kessler, 1870)

A study was carried out to investigate the daily rhythms of locomotor and feeding activity of Khajoo, Schizothorax pelzami, a candidate species for freshwater aquaculture. Using self-feeder juvenile Khajoo were exposed to a 12/12 LD cycle to determine the rhythms of locomotor and feeding activity. The effects of feeding on locomotor and feeding activity of fish were also examined. Finally, the endogenous rhythmicity under different lighting condition tested. Fish displayed a strictly diurnal feeding and locomotor activities with 98% and 84% of the total activity occurred in the photophase, respectively. In scheduled feeding, both the L-group (fed in light) and the D-group (fed in the dark) showed a diurnal locomotor activity pattern. However, the L-group had a peak of locomotor activity near the feeding time, but the D-group had a scarce locomotor activity in the scatophase with no significant change at the mealtime. Most of the individuals display free-running rhythms when exposed to different lighting condition including, constant darkness, ultradian 45:45 min LD cycle and reversed DL photo cycle. Taken together the results of this study showed that both locomotor and feeding activity have diurnal rhythms in Khajoo S. pelzami, even fish feeding had taken place at night. Additionally, the free-running locomotor activity of the fish in the absence of external light stimuli, suggests the existence of an endogenous timing mechanism in this fish species.     

Circadian locomotor rhythms in individual honeybees

ABSTRACT. The circadian locomotor (walking) rhythms of individual forager honeybees ( Apis mellifera ligustica L.) were measured under a variety of conditions. In constant dark the rhythms exhibited endogenous periodicities that were less than 24 h, whereas under constant light the periods tended to be greater than 24 h. Individual honeybees readily entrained to photoperiods, displaying a diurnal pattern of entrainment with most of the activity occurring in late photophase. Evidence is presented which suggests that foraging behaviour and general locomotor behaviour may be governed by two different circadian clock systems.     

Emergence rhythms and protandry in relation to daily patterns of locomotor activity inTrichogramma species

Summary In insect parasitoids, the mating structure of the population depends on the emergence pattern of adults and on their behaviour after emergence. In order to study some aspects of these characteristics in four species of egg parasitoid of the genusTrichogramma, laboratory experiments using automatic video analysis are performed. Adult emergence is concentrated in the morning, with an earlier time for males. The variability of the time of emergence is under genetic control. The relationships between the emergence pattern and the locomotor activity are considered by measuring individually: first, the delay between the emergence and the first locomotion which is significantly greater in females than in males and, second, the activity of newly emerged males, which is maximum at the time of the emergence of females. The locomotor activity is influenced by mating; mated females are much more active than virgin ones, mated males are less active than virgin ones. The adaptive values of the rhythmicity of emergence and of protandry are discussed together with their relationship with the patterns of locomotor activity. The results are also considered with respect to mating strategies in insect parasitoids; they actually support the hypothesis of mating occurring principally among individuals native to the same host patch inTrichogramma species.     

The effects of thyrotropin-releasing hormone, metabolites and analogues on locomotor activity in rats

Thyrotropin-releasing hormone (TRH) has generally been reported to increase locomotor activity in rats; however there are also some negative reports. In order to identify the possible causes for this discrepancy, the effects of intra-cerebroventricular injection of TRH, its metabolites 'acid TRH' (TRH-OH) and His-Pro-diketopiperazine (DKP), and two analogues 3-methyl-His-TRH and RX 77368 (3,3-dimethyl-Pro-TRH), were assessed using photocell activity cages. All compounds were tested in groups of eight rats in the afternoon (1300-1700 h), but in addition TRH and DKP were tested in two further groups of rats during the morning (0900-1230 h). TRH and DKP failed to induce a significant rise in activity during the morning test period, but TRH did have a significant effect when tested in the afternoon. Both TRH and TRH-OH caused dose dependent increases in locomotor activity, whereas DKP and the two analogues had no effect. This stimulation of activity was shown to be at least partly mediated by dopamine since locomotor enhancement was blocked in a second experiment using the dopamine antagonist alpha-Flupenthixol. The results are discussed in terms of actions on the mesolimbic dopamine system, and the importance of circadian variations within this system to the expression of peptide effects in general.     

Involvement of cortisol and sirtuin1 during the response to stress of hypothalamic circadian system and food intake-related peptides in rainbow trout,Oncorhynchus mykiss

Stress is conditioning animal welfare by negatively affecting a wide range of physiological and behavioral functions. This may be applied to circadian physiology and food intake. Cortisol, the stress-related hormone, may mediate such effect of stress, but other indirect mediators might be considered, such as sirtuin1. Then, either the independent modulatory effect or the existence of any interaction between mediators may be responsible. The circadian system is the main modulator of several integrative mechanisms at both central and peripheral levels that are rhythmically presented, thus influencing different processes such as food intake. In this way, food intake is controlled by the circadian system, as demonstrated by the persistence of such rhythms of food intake in the absence of environmental external cues. Our study aimed to evaluate the daily profile of hypothalamic mRNA abundance of circadian clock genes (clock1a, bmal1, per1 and rev-erbβ-like), and food intake regulators (crf, pomc-a1, cart, and npy) in rainbow trout (Oncorhynchus mykiss), the impact of stress on such rhythms, and the involvement of cortisol and sirtuin1 as mediators. Four cohorts of trout were subjected to 1) normal stocking density (control group), 2) high stocking density for 72 hours (stress group), 3) normal stocking density and implanted with mifepristone, a glucocorticoid receptors antagonist, and 4) mifepristone administered and stressed for 72 hours. Fish from each group were sampled every 4-h along the 24-h LD cycle, and cortisol, glucose and lactate plasma levels were evaluated. Hypothalamic mRNA abundance of clock genes, food intake regulators, glucocorticoid receptors and sirtuin1 were qPCR assayed. Our results reveal the impact of stress on most of the genes assayed, but different mechanisms appear to be involved. The rhythm of clock genes displayed decreased amplitude and averaged levels in stressed trout, with no changes of the acrophase being observed. This effect was not prevented by mifepristone. On the contrary, the effect of stress on the daily profile of crf, pomc-a1, and npy was totally prevented by mifepristone administration. Accordingly, cortisol appears to mainly mediate the effect of stress on food intake regulators through binding to specific glucocorticoid receptors within trout hypothalamus, whereas sirtuin1 is apparently mediating such effects on the circadian system in the same brain region. Further research must be performed to clarify those mechanisms through which stress influences food intake and the circadian oscillator within the same brain region, hypothalamus, in rainbow trout, and the interaction among them all.     

Dominance in demand-feeding behaviour in Arctic charr and rainbow trout: the effect of stocking density

The effects of stocking density on the demand feeding behaviour of Arctic charr Salvelinus alpinus and rainbow trout Oncorhynchus mykiss were evaluated using demand feeders in combination with a monitoring system based on automatic passive integrated transponders. The proportion of total bites accounted for by top-ranked charr and trout decreased from 87 to 15% and from 66 to 15%, respectively, when moving from the lowest to the highest densities, indicating that the ability of the highest-ranked fish to monopolize the demand feeders was reduced at high densities. However, when the individuals were grouped into quartiles, based on their individual rank, both charr and trout ranked within the upper quartile accounted for the majority of bites independent of stocking density (87 and 72% of the total, respectively). Instead of there being a single dominant individual, as was the case under low density conditions, a small group of individuals dominated the actuation of the trigger at high densities. The two species responded differently to crowding, with the total daily bite activity of charr increasing linearly with increasing density, whereas the corresponding relationship was quadratic for rainbow trout, with a peak value at 24 to 36kg m⁻³.     

Daily and seasonal rhythms of locomotor activity and adrenal function in male hedgehogs(Erinaceus europaeus L.)

Abstract

Male hedgehogs were maintained in outdoor parks, under natural climatic conditions. The general locomotor activity was recorded over one year in five hedgehogs, using an infra‐red producer‐receptor system registering entering or leaving the nest box in relation to time. Simultaneously, thecortico‐adrenal activity was studied monthly by sampling without disturbing, at 4 h intervals over a period of 24 h, in groups of 6 animals with a catheter inserted in the left carotid artery. The corticosteroids were assayed using a competitive protein binding technique.

In our study, hedgehogs living in Western Central France showed:

(1) from February‐March to August‐September a daily nocturnal locomotor activity well synchronized with sunset and sunrise,

(2) between August‐September and February‐March an alternation of resting and activity periods which constitute the hibernating period. The activity periods occur still during the night, but there are no relationships with sunset or sunrise,

(3) from February to October, a nycthemeral rhythm of plasma corticosteroids wi th an evening maximum and a morning minimum, as in laboratory animals with nocturnal locomotor activity,

(4) after October, during hibernation, significant variations of plasma corticos teroids with an irregular.pattern (shifting of the maximum or biphasic profile),

(5) a clearly annual cycle of the daily plasma corticosteroids levels, with a considerable increase in autumn (maximum in December), a significant decrease in January and a minimum from January to May.

These daily and seasonal variations of locomotor activity and cortico‐adrenal activity are related to the seasonal variations of the environment.     

Influence of light and food on the circadian clock in liver of rainbow trout,Oncorhynchus mykiss

Several reports support the existence of multiple peripheral oscillators in fish, which may be able to modulate the rhythmic functions developed by those tissues hosting them. Thus, a circadian oscillator has been proposed to be located within fish liver. In this vertebrate group, the role played by the circadian system in regulating metabolic processes in liver is mostly unknown. We, therefore investigated the liver of rainbow trout (Oncorhynchus mykiss) as a potential element participating in the regulation of circadian rhythms in fish by hosting a functional circadian oscillator. The presence and expression pattern of main components of the circadian molecular machinery (clock1a, bmal1, per1 and rev-erbβ-like) were assessed. Furthermore, the role of environmental cues such as light and food, and their interaction in order to modulate the circadian oscillator was also assessed by exposing animals to constant conditions (absence of light for 48 h, and/or a 4 days fasting period). Our results demonstrate the existence of a functional circadian oscillator within trout liver, as demonstrated by significant rhythms of all clock genes assessed, independently of the environmental conditions studied. In addition, the daily profile of mRNA abundance of clock genes is influenced by both light (mainly clock1a and per1) and food (rev-erbβ-like), which is indicative of an interaction between both synchronizers. Our results point to rev-erbβ-like as possible mediator between the influence of light and food on the circadian oscillator within trout liver, since its daily profile is influenced by both light and food, thus affecting that of bmal1.     

Daily rhythms of activity in horses housed in different stabling conditions

Total locomotor activity was studied in 10 Thoroughbreds housed under a natural 12/12 light/dark cycle. Five horses were housed in individual boxes, and five were housed in individual boxes with a paddock. In order to record locomotor activity, on each horse was placed an Actiwatch-Mini® (Cambridge Neurotechnology Ltd, UK), actigraphy-based data loggers that record a digitally integrated measure of motor activity. Locomotor activity in the different experimental conditions was evaluated by visual inspection. Average amount of activity (bout of activity/hour) during light and dark phase and cosine Peak (time of peak activity) were calculate using Actiwatch Activity Analysis 5.06. Student's t-test was used to determine significant differences. The results from this study underline the influence of stabling conditions on activity rhythms in horses; furthermore, we clearly established that in horses, the activity rhythm reaches its peak in the middle of the day.     

Influence of growth rate on white muscle dynamics in rainbow trout and brook trout

In trout, fast growth stimulated white muscle fibre hypertrophy ( P 0·001) and hyperplasia ( P <0·01) in outer fibres but not in deep fibres. Glycogen was most prevalent in outer fibres ( P <0·01) and in brook trout ( P <0·01) that on average had three to four times larger fibres than rainbow trout.     

Circadian rhythms and the evolution of photoperiodic timing in insects

This review discusses possible evolutionary trends in insect photoperiodism, mainly from a chronobiological perspective. A crucial step was the forging of a link between the hormones regulating diapause and the systems of biological rhythms, circadian or circannual, which have independently evolved in eukaryotes to synchronize physiology and behaviour to the daily cycles of light and darkness. In many of these responses a central feature is that the circadian system resets to a constant phase at the beginning of the subjective night, and then ‘measures’ the duration of the next scotophase. In ‘external coincidence’, one version of such a clock, light now has a dual role. First, it serves to entrain the circadian system to the stream of pulses making up the light/dark cycle and, second, it regulates the nondiapause/diapause switch in development by illuminating/not illuminating a specific light sensitive phase falling at the end of the critical night length. Important work by A. D. Lees on the aphid Megoura viciae using so‐called ‘night interruption experiments' demonstrates that pulses falling early in the night lead to long‐day effects that are reversible by a subsequent dark period longer than the critical night length and also show maximal sensitivity in the blue–green range of the spectrum. Pulses falling in the latter half of the night, however, produce long‐day effects that are irreversible by a subsequent long‐night and show a spectral sensitivity extending into the red. With movement to higher latitudes, insects develop genetic clines in various parameters, including critical night length, the number of long‐night cycles needed for diapause induction, the strength of the response, and the ‘depth’ or intensity of the diapause thus induced. Evidence for these and other types of photoperiodic response suggests that they provided strong selective advantages for insect survival.     

Natural reproduction of anadromous rainbow trout in Norway

Six naturally reproduced 0+ rainbow trout were caught in a Norwegian river in 1994. This is the second report and first recorded sample of descendants from anadromous parents found in a Norwegian river. If this is not a unique event, the finding bodes ill for future conservation of native anadromous Salmonids.     

Circadian rhythms of melatonin in European starlings exposed to different lighting conditions: relationship with locomotor and feeding rhythms

In passerine birds, the periodic secretion of melatonin by the pineal organ represents an important component of the pacemaker that controls overt circadian functions. The daily phase of low melatonin secretion generally coincides with the phase of intense activity, but the precise relationship between the melatonin and the behavioral rhythms has not been studied. Therefore, we investigated in European starlings (Sturnus vulgaris) (1) the temporal relationship between the circadian plasma melatonin rhythm and the rhythms in locomotor activity and feeding; (2) the persistence of the melatonin rhythm in constant conditions; and (3) the effects of light intensity on synchronized and free-running melatonin and behavioral rhythms. There was a marked rhythm in plasma melatonin with high levels at night and/or the inactive phase of the behavioral cycles in almost all birds. Like the behavioral rhythms, the melatonin rhythm persisted for at least 50 days in constant dim light. In the synchronized state, higher daytime light intensity resulted in more tightly synchronized rhythms and a delayed melatonin peak. While all three rhythms usually assumed a rather constant phase relationship to each other, in one bird the two behavioral rhythms dissociated from each other. In this case, the melatonin rhythm retained the appropriate phase relationship with the feeding rhythm. Accepted: 10 December 1999     

Circadian rhythms of proliferation events in two mouse carcinomas

We studied the index of DNA synthesis (DNAs) of two cellular carcinomas: the hepatocellular ES12a and the mammary TN60 of mice, throughout one circadian cycle. In the results, we observed that both tumors have circadian rhythms (CRs), but the peaks of DNAs vary. Besides, the mean of DNAs along 24 h shows significative differences, the TN60 has higher values than the ES12a. These observed CR in the DNAs index in both carcinomas mean that, at least in partly, the proliferation of cancer cells can be regulated by endocrine factor as it normally occurs in ordinary cells. The big problem we can find for the chronopharmacology is that it is impossible to know in advance the rate of proliferation of each tumor.     

Glucose 6-phosphate dehydrogenase in rainbow trout

Electrophoretic analysis of glucose 6-phosphate dehydrogenase from liver and blood of rainbow trout revealed a complex series of bands, which could differ between fish. The partial interconvertible nature of these bands was demonstrated with enzyme that had been incompletely inactivated at pH 8.4. In a single population of 40 fish, a homozygote and a heterozygote for an electrophoretic variant allele were found. We suggest that G6PD in rainbow trout liver and blood is determined by two alleles at a single locus, with posttranslational modification responsible for the complex electrophoretic patterns seen. The basis for this variation appears to be NADH binding to the protein molecule. Another variant and other properties of the enzyme are described.Supported in part by the State of California Department of Mental Hygiene and by USPHS Grants GM-15253, HD-04612, HD-00315, HD-05615, and HL-15125. One of us (S.D.C.) was a Special Postdoctoral Fellow of NIAMD (No. 1F03AM-40, 329-01) during part of this work.     

Circadian rhythm of locomotor activity in the Japanese honeybee, Apis cerana japonica

Abstract.  To reveal circadian characteristics and entrainment mechanisms in the Japanese honeybee Apis cerana japonica , the locomotor-activity rhythm of foragers is investigated under programmed light and temperature conditions. After entrainment to an LD 12 : 12 h photoperiodic regime, free-running rhythms are released in constant dark (DD) or light (LL) conditions with different free-running periods. Under the LD 12 : 12 h regime, activity offset occurs approximately 0.4 h after lights-off transition, assigned to circadian time (Ct) 12.4 h. The phase of activity onset, peak and offset, and activity duration depends on the photoperiodic regimes. The circadian rhythm can be entrained to a 24-h period by exposure to submultiple cycles of LD 6 : 6 h, as if the locomotive rhythm is entrained to LD 18 : 6 h. Phase shifts of delay and advance are observed when perturbing single light pulses are presented during free-running under DD conditions. Temperature compensation of the free-running period is demonstrated under DD and LL conditions. Steady-state entrainment of the locomotor rhythm is achieved with square-wave temperature cycles of 10 °C amplitude, but a 5 °C amplitude fails to entrain.     

Plasticity of diel and circadian activity rhythms in fishes

In many fish species, some individuals arediurnal while others are nocturnal. Sometimes,the same individual can be diurnal at first andthen switch to nocturnalism, or vice-versa.This review examines the factors that areassociated with such plasticity. It covers thebreakdown of activity rhythms during migration,spawning, and the parental phase; reversals ofactivity patterns during ontogeny or from oneseason to the next; effects of light intensity,temperature, predation risk, shoal size, foodavailability, and intraspecific competition.Case studies featuring goldfish (Carassiusauratus), golden shiner (Notemigonuscrysoleucas), lake chub (Couesiusplumbeus), salmonids, sea bass (Dicentrarchus labrax), and parentalsticklebacks and cichlids illustrate some ofthese influences. It is argued that mostspecies have a circadian system but that havingsuch a system does not necessarily imply strictdiurnalism or nocturnalism. Rigidity ofactivity phase seems more common in species,mostly marine, that display behavioral sleep,and for these animals the circadian clock canhelp maintain the integrity of the sleepperiod and ensure that its occurrence takes place atthat time of day to which the animal's sensoryequipment is not as well adapted. However, inother fishes, mostly from freshwater habitats,the circadian clock seems to be used mainly foranticipation of daily events such as thearrival of day, night, or food, and possiblyfor other abilities such as time-place learningand sun compass orientation, rather than forstrict control of activity phase. In thesespecies, various considerations relating toforaging success and predation risk maydetermine whether the animal is diurnal ornocturnal at any particular time and place.     

Circadian rhythms in zebrafish (Danio rerio) behaviour and the sources of their variability

Over recent decades, changes in zebrafish (Danio rerio) behaviour have become popular quantitative indicators in biomedical studies. The circadian rhythms of behavioural processes in zebrafish are known to enable effective utilization of energy and resources, therefore attracting interest in zebrafish as a research model. This review covers a variety of circadian behaviours in this species, including diurnal rhythms of spawning, feeding, locomotor activity, shoaling, light/dark preference, and vertical position preference. Changes in circadian activity during zebrafish ontogeny are reviewed, including ageing-related alterations and chemically induced variations in rhythmicity patterns. Both exogenous and endogenous sources of inter-individual variability in zebrafish circadian behaviour are detailed. Additionally, we focus on different environmental factors with the potential to entrain circadian processes in zebrafish. This review describes two principal ways whereby diurnal behavioural rhythms can be entrained: (i) modulation of organismal physiological state, which can have masking or enhancing effects on behavioural endpoints related to endogenous circadian rhythms, and (ii) modulation of period and amplitude of the endogenous circadian rhythm due to competitive relationships between the primary and secondary zeitgebers. In addition, different peripheral oscillators in zebrafish can be entrained by diverse zeitgebers. This complicated orchestra of divergent influences may cause variability in zebrafish circadian behaviours, which should be given attention when planning behavioural studies.     

Isolation of rainbow trout (Oncorhynchus mykiss) intestinal intraepithelial lymphocytes (IEL) and measurement of their cytotoxic activity

Established methods for isolating intraepithelial lymphocytes (IEL) from mouse small intestine were modified to facilitate the isolation of IEL from rainbow trout gut epithelium. A 1 h incubation in 1 mMDTT/EDTA was required to maximise the separation of the epithelial compartment from the underlying lamina propria. Epithelial cell content was reduced by filtration on nylon wool columns followed by centrifugation on a 40% Percoll cushion. Most IEL pelleted through the 40% Percoll [high density (HD) IEL] although significant numbers banded out at the medium/40% Percoll interface [low density (LD) IEL]. The majority (∼90%) of HD IEL were<12·5 μm in size, had a pleiomorphic nucleus and obvious mitochondria. LD IEL were larger cells, containing more cytoplasm with abundant ribosomes. Neither HD nor LD IEL appeared to contain ‘ cytotoxic ’ granules. Despite this, in a non-radioactive cytotoxicity assay (LDH release) with EL4 mouse thymoma cells as targets, significant killing was observed by both the HD and LD IEL.