Influence of time of food administration on daily rhythm of total locomotor activity in ponies

The activity rhythm can be entrained by nonphotic cues, especially food availability. Daily feeding schedules can act as “Zeitgeber” to synchronize the circadian system. In this study, the authors evaluated the influence of different feeding schedules on the daily rhythm of total locomotor activity in ponies. Six clinically healthy Shetland ponies were kept under natural 12/12-h light/dark cycle and monitored during 4 different feeding schedules: fed twice (at 8 am and 8 pm), fasted, fed at 8 pm, fed at 8 am, and fed twice a day again. Water was available ad libitum. To record total activity, we equipped the animals with actigraphy-based data loggers (Actiwatch-Mini). Two-way analysis of variance revealed a significant main effect of the time of day and no effect of feeding schedules on the amount of total locomotor activity. Locomotor activity showed daily rhythmicity in all experimental conditions, with diurnal acrophase. The amplitude of the rhythms and their robustness statistically changed across all experimental conditions. Our findings support the theory that when given essentially free choice hay, the time of feeding did not entrain activity, and suggest that feeding behavior can influence the distribution of locomotor activity during a 24-hour period in ponies, with changes in the amplitude and robustness of the rhythm.     

The regulation of food intake and correlated energy balance in mice.

In order to study the regulation of food intake and correlated body energy metabolism, the effect of restricted feeding during the light period in female IVCS mice was investigated. Access to food and water was restricted (RF group) for 3 weeks only from 10:00 hr to 17:00 hr, and that in the control group remained ad libitum. After starting food restriction (day 1), mean food intake decreased to 10% of the control value, then rose sharply, over the next 3 days, to reach 70% of the control value. Then, it decreased gradually to about 50% of the control value and remained at this low level thereafter. There was no significant difference between mean body weights for the two groups. Feed-efficiency was considered, therefore, to be higher in the RF than in the control group. RF-treatment increased plasma corticosterone levels and decreased locomotor activity. However, the diurnal patterns of plasma corticosterone levels and locomotor activity observed suggest that the circadian rhythm, synchronized with the light-dark cycle, persisted during RF-treatment. These findings suggest that restricted feeding during the naturally inactive phase (light period) induces a decrease in food intake. Animals seem to adapt to underfeeding, at least partly, by increasing feed-efficiency and plasma corticosterone levels and decreasing locomotor activity.     

Daily rhythm of tear production in normal horse

Objective  This study was designed to assess the daily rhythm of tear production in clinically healthy horses, to compare left eye and right eye, and to evaluate the influence of time and gender.
Animal studied  For our study 18 horses (nine female and nine male) were subjected to three different light/dark (L/D) schedules: 12/12 L/D cycles, constant light (24/0 L/D) and constant darkness (0/24 L/D).
Procedures  In all subjects Schirmer tear tests were performed at 4-h intervals over a 24-h period.
Results  A circadian rhythm of tear production was found during the 12/12 L/D period and during constant darkness. Also our results showed a statistical significant difference comparing left eye and right eye, and between gender.
Conclusions  Our findings would suggest that the time of tear evaluation is significant in the diagnosis of tear film disorders, and that the difference between the two eyes and the two genders should be taken into consideration during the ophthalmic exam.     

Daily rhythm of tear production in normal dog maintained under different Light/Dark cycles

This study was conduced to assess the daily rhythm of tear production in clinically healthy dog. For our study eight female purebred Beagles were subjected to three different Light/Dark schedules: 12/12 L/D, 24/0 L/D and 0/24 L/D cycles. In all subjects Schirmer tear test I was performed at 4 h intervals over a 24 h period. A statistical significant effect of photoperiod was observed comparing the three different L/D schedules, and a statistical significant difference was observed comparing left and right eye during the 12/12 L/D schedule. We demonstrated daily variation of tear production in dogs maintained under an L/D cycle. We also provided strong evidence that the rhythm of tear production is endogenously generated because it persisted in constant darkness. Although the range of excursion of the daily/circadian oscillation in STT I (about 2 mm/min) is likely too narrow to be of clinical significance, it is statistically significant and may have physiological implications not yet appreciated.     

The effect of ahemeral light and dark cycles on patterns of food intake by the laying hen

1. Diurnal food intake rhythms of laying hens were studied under 21, 24 and 30‐h cycles, using either a constant 12‐h photoperiod or a 10‐h scotoperiod in each cycle. The feeding patterns essentially followed a circadian periodicity under all experimental situations. The peak in food intake which normally occurs before “sunset” in a 24‐h cycle was consistently observed to be timed from the onset of the previous dark period in each light and dark cycle, regardless of cycle length.

2. This study demonstrates that the laying fowl makes use of an endogenous biological rhythm to regulate its feeding behaviour. A light to dark transition in a light and dark cycle is the primary signal for phase‐setting the pattern of food intake.     

Effects of interrupted lighting regimens on the feeding activity of the laying fowl

Segmentation of the main light period of an 8L:4D:2L:10D regimen into 30 min light, 30 min dark did not affect total feeding activity, rate of feeding or total intake of laying hens. When 15 min light and 45 min dark was provided each hour feeding activity and food intake were reduced, while rate of feeding and feeding during the dark periods increased. No feeding occurred in the 10 h 'night'. Hens subjected to interrupted lighting showed less feeding activity than those on a 14L:10D regimen. Insertion of a 4 h dark period in the 14 h subjective day of laying hens increased their rate of feeding, but reduced total intake. The pattern of feeding activity depended on the position of the 4 h dark period. The largest modification of feeding activity occurred on a 8L:4D:2L:10D regimen; 20% of activity occurred in the last 2 h of the apparent day. Feeding occurred during the 4 h dark period, but not during the 10 h 'night'.     

Involvement of thalamic paraventricular nucleus in the anticipatory reaction under food restriction in the rat

To investigate which brain regions are involved in the anticipatory activity in rats restricted feeding for 2 hr, we examined c-Fos expression before and after feeding. Only the thalamic paraventricular nucleus (tPVN) showed c-Fos expression before feeding than after feeding. After the anticipatory locomotor activity rhythm was established, lesioning the tPVN attenuated this rhythm, but not the light-dark entrained rhythm. The anticipatory increase of blood corticosterone levels was not established in long-term tPVN-lesioned rats. These results suggest that the tPVN is involved in the expression of anticipatory reactions under a food-restricted regimen.     

Characterizing behavioral sleep using actigraphy in adult dogs of various ages fed once or twice daily

Adult dogs possess strong diurnal locomotor activity/rest rhythms, and sleep/wake patterns have been characterized. However, behavioral sleep/wake data are lacking related to aging and daily feeding pattern. Three groups (young adults [Y], 1.5–4.5 years; middle-aged adults [M], 7–9 years; and senior, 11–14 years) of beagles (N = 48) wore the Actiwatch activity monitoring system (Respironics Co., Inc., Bend, OR) for 3 days while housed indoors with 12-hour light/dark schedule and fed once or twice daily. Actiware-Rhythm software (version 5.52; Respironics Co., Inc., Bend, OR) was used to estimate behavioral sleep or wake from locomotor activity data. All dogs demonstrated diurnal sleeping patterns. Total wake minutes during the light phase declined with age (P < 0.05) and differed by 7.7% and 10.2% for middle-aged adults and seniors, respectively, compared with young adults. Further analysis revealed that increased light phase nap bouts (P < 0.008), not increased nap duration, caused this decline. Total sleep minutes during the night increased with age, as middle-aged adults and seniors slept at least 38 (P = 0.01) more minutes than young adults. Increased sleep time at night resulted from a longer sleep interval duration (P = 0.05), delayed morning activity onset time (P = 0.02), and marginally fewer waking bouts (P = 0.07). Independent of age, twice-daily feeding significantly influenced daytime sleeping patterns but did not affect total minutes recorded as sleep during the day. Interestingly, napping bouts decreased significantly (P = 0.01) and napping duration increased (P = 0.0001) when fed twice-daily. Twice-daily feeding was also associated with earlier sleep onset time at night and onset of morning activity, as well as shortened sleep interval. Clear changes in behavioral sleep patterns were observed with age and daily feeding schedule.     

Light exposure during night suppresses nocturnal increase in growth hormone secretion in Holstein steers

To understand the regulatory mechanism of the secretory rhythm of GH and the involvement of melatonin (MEL) in GH regulation in cattle, daytime and nighttime profiles of GH secretion and the effect of a photic stimulation on nocturnal GH and MEL secretion were investigated in Holstein steers. Steers were kept under a constant lighting condition of 12 h of light (LIGHT; 500 lx, 0600 to 1800 h):12 h of dark (DARK; 10 lx, 1800 to 0600 h). In Exp. 1, blood was taken for 4 h at 15-min intervals during LIGHT (1100 to 1500 h) and DARK (2300 to 0300 h), respectively. The sampling was also performed from 0500 to 0900 h, with the usual light transition (light onset at 0600 h; morning sampling). In Exp. 2, steers were exposed to light (500 lx) for 1 h from 0000 to 0100 h. Plasma GH and MEL concentrations were determined by RIA and enzyme immunoassay, respectively. Both GH (P < 0.05) and MEL (P < 0.01) concentrations in plasma for 4 h during DARK were greater than those during LIGHT. On the other hand, although MEL concentrations were decreased after the light onset at 0600 during the morning, GH release was not altered. Increased GH secretion during DARK was suppressed (P < 0.01) by the 1 h of light exposure, as were MEL concentrations (P < 0.05). Pineal MEL, which was affected by the photic condition, may play an important role in the secretory rhythm of GH secretion in cattle.     

Circadian variation in heart rate, blood pressure, body temperature and EEG of immature broiler breeder chickens in restricted-fed and ad libitum-fed states

1. Heart rate, intra-aortic blood pressure, deep body temperature and telencephalic EEG were monitored by radiotelemetry in 6 freely moving immature broiler breeders (three in each of two years), during routine food restriction and then ad libitum feeding, over two 24-h periods in each feeding state.2. Heart rate, blood pressure and body temperature were all higher during ad libitum than restricted feeding, and heart rate and body temperature were higher by day (12 h) than at night (12 h). The decreases in heart rate and body temperature at night were greater during restricted than ad libitum feeding. Blood pressure tended to be higher at night, except in year 2 during restricted feeding. Body temperature and ambient temperature were higher in year 2 than year 1.3. During restricted feeding, marked peaks in heart rate, blood pressure and body temperature in the 15 min after provision of the daily food ration at 09:00 h, when birds were eating, were equivalent to corresponding values seen during ad libitum feeding.4. Relative powers in delta (1 to 4 Hz) and theta (4 to 8 Hz) frequency bands of the EEG power spectrum were higher at night in year 2 only, while power in the alpha (8 to 12 Hz) band was higher at night in both years.5. It is concluded that most of the variation in heart rate, blood pressure and body temperature between feeding states and times of day/night can be accounted for in terms of variation in food intake and energy expenditure. The greater slow wave (delta, theta) EEG activity seen after lights-off in year 2 may reflect non-paradoxical sleep at that time.     

Influence of sudden changes in management program on physiological and behavioral parameters in hens

The present study was designed to test the effects of sudden changes of food access and light duration on the physiological and behavioral parameters of hens. The physiological parameters investigated were heart rate (HR), body temperature (BT), and locomotor activity (LA) using a radiotelemetry system. After implantation of the telemetry transmitters, six hens were housed individually in cages under constant environmental conditions for 10 days with a photoperiod of 15 h light (04.00–19.00 hours), and food was available ad libitum at all times. After that, the same hens were subjected to a feed withdrawal trial, from 12.00 to 08.30 hours, followed by a lighting hour reduction trial by changing the time of lights‐off from 19.00 to 14.00 hours. The physiological and behavioral data were recorded for 2 days before each trial, as control data. With the feed withdrawal trial, during the light and dark periods, HR and BT were significantly lower in the hens without food access than in the control. Whereas, LA was significantly lower only during the light period in the hens without food access than in the control. Further, the time spent resting increased significantly, but the time spent feeding decreased significantly in the hens without food access than in the control. Also, the number of times the cage was pecked and pecking of the feeder occured at a significantly higher level, while the number of times beaks were wiped occured at a significantly lower level in the hens without food access than in the control. With the lighting hour reduction trial, during the light period, HR and BT were significantly higher, whereas LA was significantly lower in the ’sudden light‐off’ treated hens than in the control. In addition, during the dark period, HR, BT and LA were significantly higher in the sudden light‐off treated hens than in the control. Moreover, in the sudden light‐off treated hens, the time spent preening and feeding decreased significantly, but the time spent resting increased significantly than in the control. It is concluded that sudden changes in a management program might result in many significant differences as were found in the physiological and behavioral parameters of hens in the present study.     

Use of two cloprostenol administrations 11.5 days apart efficiently synchronizes oestrus in photostimulated multiparous dairy goats in the non-breeding season

This study assessed the efficiency of synchronous oestrous induction by light programme followed by two doses of cloprostenol in acyclic Saanen goats of different parity orders. Primiparous (n = 22) and multiparous (n = 33) goats were subjected to 16 hr of light and 8 hr of darkness for 60 days (D0-D60), starting 10 days after the winter solstice. All goats received 120 µg cloprostenol doses on D130 (morning) and D141.5 (afternoon) (11.5 days apart). Oestrus behaviour, ovarian follicular dynamics and serum progesterone (P4) analyses were recorded from D0 to D174 at different intervals. Animals in oestrus after D141.5 were randomly assigned into two groups: assisted natural mating (NM) or artificial insemination (AI; 10–24 hr after oestrus onset with frozen-thawed semen). From D57 to D120, 89.0% of goats presented large follicles (5–8 mm) and P4 concentrations were subluteal from D0 to D120. More multiparous compared to primiparous goats (54.5%, 18/33 vs. 18.2%, 4/22) exhibited oestrus after both injections. More primiparous compared to multiparous goats (54.5%, 12/22 vs. 12.1%, 4/33) did not exhibit oestrus after any injection. A total of 35 goats (64%) were in oestrus after the second prostaglandin injection and were subjected to NM or AI. The conception rate was similar among primiparous (70.0%, 7/10) and multiparous (68.0%, 17/25) goats but the pregnancy rate differed, being 31.8% (7/22) and 51.5% (17/33), respectively. No interaction was found between parity order and P4 concentrations in does that became pregnant or not. Thus, the association between light programme (60 days, starting at the beginning of winter) and two cloprostenol administrations 11.5 days apart (starting 70 days after the end of the light treatment) resulted in sufficient synchronous oestrous response in multiparous acyclic Saanen goats to reach satisfactory fertility levels after both NM and AI.     

Effect of lighting period on the performance of male turkeys from 6 to 18 weeks of age

A total of 468 male turkeys which had been fed ad libitum and received light for 23 h each day for the first 6 weeks oflife were used to study the effects of subsequent lighting pattern on performance. Three lighting treatments were used: a constant 23 h/d (L1), a constant 14 h/d (L2) and a step‐down pattern in which the light period was reduced from 22 h/d, by 1 h each week, to 14 h/d at 14 weeks, after which it was kept constant until 18 weeks (L3). Within each lighting treatment there were two feeding treatments: birds were either offered food ad libitum or received a restricted amount of food that was the same for all lighting treatments.

At 18 weeks of age there was no difference between body weights of birds receiving treatments L2 and L3, but birds receiving treatment Li were significantly (P< 0.05) heavier. This difference was independent of feeding treatment. Despite the difference in body weight voluntary food intake was slightly greater in birds receiving treatment L2 than in those receiving Li. As a result, a significantly (P < 0.01) more efficient food conversion was associated with L1 than with L2 and L3.     

Effect of age and feeding schedule on diurnal rest/activity rhythms in dogs

Dogs exhibit biorhythms like diurnal sleep/wake and rest/activity behavior patterns with circadian rhythmicity and, similar to other mammalian species, show age-dependent changes in activity rhythms. This study sought to further characterize night/day locomotor activity patterns in adult dogs of various ages, and to examine the effect of feeding frequency (once vs. twice). Three groups (early adults [EA], 1.5-4.5 years; late adults [LA], 7-9 years; senior, 11-14 years) of beagles (N = 48) wore the Actiwatch activity monitoring system for 3 days while housed indoors with 12-hour light/dark schedule. Activity recording devices were used to collect actigraphy data when dogs were on a once- or twice-daily feeding regimen. All dogs demonstrated a circadian activity pattern with high levels of daytime activity and low levels of nighttime activity. The main effect of age differed for both daytime (P < 0.0001) and nighttime (P = 0.002) activity counts. Daytime activity in senior dogs was 17% and 42% lower compared with LA and EA dogs, respectively. With nighttime activity, both LA and seniors had significantly lower counts compared with the EA. Compared to once-daily feeding, twice-daily feeding significantly increased night activity, night/day activity ratio, and activity counts 60 minutes before the light phase across all 3 age-groups. This study provides a comprehensive characterization of age-related changes in locomotor behavior patterns in dogs and uniquely demonstrates that frequency of feeding can influence nighttime activity levels, which is partially associated with level of prelight onset of activity.     

An evaluation of adrenal mass and adrenal cholesterol as measures of adrenal activity

1. The effects of twice daily injections of corticotrophin (1 IU/kg body weight) or restriction of food intake to 75% of normal on body mass, adrenal mass and adrenal cholesterol were determined on chicks from 1 to 21 d of age. 2. Only the birds subjected to restricted feeding showed a reduced growth rate. 3. There was no adrenal hypertrophy in birds receiving corticotrophin but in the restricted group there was transient hypertrophy at 2 weeks. 4. Depletion of adrenal cholesterol was noted only in the birds receiving corticotrophin. 5. It is concluded that neither depletion of cholesterol nor hypertrophy is an inevitable consequence of enhanced adrenal cortical activity.     

A comparison of daily total locomotor activity between the lactation and the dry period in dairy cattle

The objective of this study was to investigate the influence of farming management on the total locomotor activity (TLA) behaviour in dairy cattle. We recorded 24 h/day TLA in five not pregnant Holstein Friesian cows during parts of the lactation and dry periods, by means of an activity monitoring system (Actiwatch mini®) for seven days in each period. During mild lactation (period 1) animals were milked and fed twice a day. During the dry (period 2) they were kept to graze all day. In both periods hay and water were available ad libitum. Differences between the photophase and the scotophase were evaluated with a Student t-test. One-way repeated measure ANOVA was used to determine a statistical significant effect of time. A trigonometric statistical model was used to describe the main rhythmic parameters: mean level, amplitude, acrophase and robustness of rhythm.Our results showed a circadian rhythm of daily TLA in both periods, with different percentages of robustness, and acrophase in the middle of the photophase. The different patterns of activity in the two periods were attributed to the management practise during milking period. These results could be taken in consideration during farming management for the evaluation of such systems used in livestock, with respect to production and welfare.     

光照节律对肉兔生长性能、血清生化指标、肉品质和动物福利的影响

旨在研究光照节律对肉兔生长性能、肉品质、血清生化指标和行为的影响。选取135只35日龄断奶伊拉公兔,随机分为3个处理,每个处理15个重复,每个重复3只肉兔,设置12 h光暗循环(12L∶12D)、24 h光照(24L)和24 h黑暗(24D)的3种光照节律,光照强度为100 lx,预试期为7 d,试验期为35 d。结果表明,与12L∶12D组相比,24D组肉兔21~35 d的平均日采食量(ADFI)、饲料转化率(FCR)、半净膛率、背最长肌pH和熟肉率显著提高(P<0.05),血糖浓度显著降低(P<0.05),其中FCR和半净膛率在各个处理组中最高(P<0.01)。24L组的皮指数显著低于12L∶12D和24D组(P<0.01),而白蛋白(ALB)和肌肉失水率显著高于于12L∶12D和24D组(P<0.01)。各个处理组间肌肉肉色以及肌肉常规营养指标没有显著差异(P>0.05)。24D组的肉兔坐的行为持续时间最少(P<0.01),啃咬行为频率较低(P<0.05),运动、直立、站立行为频率最高(P<0.05)。结果显示,长时间黑暗环境可以提高肉兔的生长性能,降低血糖浓度。同时,肉兔在长期的黑暗中表现出更多的社会性、较少的恐惧和焦虑,显示出良好的动物福利。     

Fasting heat production of Saanen and Anglo Nubian goats measured using open‐circuit facemask respirometry

This study aimed to establish the heat production (HP) of Saanen and Anglo Nubian goats at absorptive (feeding) and at post‐absorptive (fasting) statuses to determine the adequate period of fasting required for the measurement of basal metabolism. Gas exchange was recorded via open‐circuit facemask respirometry. Six non‐lactating and non‐pregnant goats of each breed, Saanen (49.2 ± 3.2 kg of body weight, BW) and Anglo Nubian (64.0 ± 3.0 kg BW), were placed in individual pens with ad libitum access to the same total mixed ration. After a 3‐day feeding period, the animals were subjected to fasting (no feed), and the gas exchange measurement was performed for 30 min at 0, 12, 20, 36, 44, 60 and 68 h after fasting. The daily HP of the Saanen and Anglo Nubian goats averaged 557.4 ± 38.7 and 357.1 ± 35.3 kJ/kg^0.75 BW day respectively. During fasting, the methane production decreased exponentially in both breeds, and the critical time when methane production was statistically equal to zero was at 31 h of fasting for the Saanen goats and at 40 h for the Anglo Nubian goats. The daily HP and respiratory exchange rate during fasting decreased up to 60 h. Taken together, our results suggest that the ideal period to measure fasting heat production (FHP) for goats fed at maintenance levels should be between 40 h and 60 h of fasting. Consequently, the daily FHP, after 60 h of fasting, of Saanen and Anglo Nubian goats was 183.3 ± 16.3 and 211.1 ± 11.5 kJ/kg^0.75 BW day respectively. The results presented herein are relevant for future studies of energy metabolism in goats.     

Intermittent lighting and feeding schedules for broilers incorporating long periods of darkness

1. Intermittent lighting and feeding schedules incorporating long periods of darkness and periods without access to food were applied to growing broilers.

2. Birds exposed to a 2 h light(L): 10 h dark(D) lighting schedule with feeding restricted to the light periods ate significantly less food and grew more slowly than conventionally‐reared birds. Satisfactory growth and efficiency of food utilisation were obtained by allowing these birds access to food during the dark periods.

3. Altering the lighting schedule to 2L:6D resulted in birds with food intakes and growth rates similar to those reared conventionally, even when feeding was restricted to the light periods.

4. Releasing birds from the light and food restriction for the 2 weeks preceding slaughter resulted in greater food consumption which was not characterised by significantly better growth or food utilisation.

5. Feeding a diet of high energy or pelleting a diet of low energy during the period of restriction increased food intake and improved growth rate.

6. The response of broilers to intermittent lighting and feeding was not significantly influenced by ambient temperature within the range 16 to 35 °C or by the energy concentration of the diet fed before the introduction of the intermittent schedule.     

Nutritionally induced body weight loss and ovarian quiescence in Shiba goats

Four female Shiba goats were used to determine the influence of body weight loss by dietary restriction on estrous cyclicity. The dietary restriction was started on the day following ovulation. The goats were fed hay cube and straw at an amount of 30% of energy requirement based on weekly body weight measurement. The ovaries were monitored daily by transrectal ultrasonography and blood samples were collected daily by jugular venipuncture for ovarian steroids analysis. After the start of food restriction, all animals lost body weight and entered ovarian quiescence. Intervals to the onset of ovarian quiescence tended to depend on the body weight of each animal at the start of food restriction. The mean concentration of progesterone during the mid-luteal phase (from 7 to 13 days after ovulation) in the last estrous cycle before ovarian quiescence was significantly lower than that in normal estrous cycle of the control period (19.7 +/- 2.8 vs 12.3 +/- 2.2 ng/ml, P<0.05), whereas there was no significant difference in the length of the luteal phase, determined as the period when corpora lutea existed and concentrations of progesterone were equal to or greater than 1 ng/ml (15.8 +/- 1.5 vs 15.0 +/- 2.8 days, P>0.1). A rise of estradiol concentration and follicular growth in the follicular phase following a decline of progesterone level after luteal regression tended to be suppressed at the onset of ovarian quiescence. It seems that the present results are consistent with previous findings that nutritionally induced body weight loss influences the secretion of ovarian steroids and eventually induces ovarian quiescence.