棕背Ping昼夜活动节律的研究

The diurnal activity rhythm of Clethrionomys rufocanus was studied under three different food conditions in a laboratory. The activity occurred both in the daytime and at night, but mainly at night (19:00--4:00). The mice fed with Mouse food exhibited six small peaks in their daily activity, and those fed with grass or hay exhib-ited seven, but the peak of the out-nest night activity was 2 ～ 3 hours earlier. The activity amount of out-nest was 30 518.0 ± 3 694.9 s for those fed with grass, the next was 21 811.7 ± 2 288.0 s for those fed with hay,and the least was 15 038.0 ± 666.0 s for those fed with mouse food. The activity amount of feeding was 10867.3± 1 612.1 s for those fed with grass, much more than those fed with mouse food and hay. The activity amount for drinking was 988.5 ± 79.1 s (fed with hay), 568.9 ± 60.9 s (fed with mouse food) and 139.3 ±47.2 s (fed with grass).     

Effect of food intake on urinary excretions of histamine, N tau-methylhistamine, imidazole acetic acid and its conjugate(s) in humans and mice

The urinary excretions by young healthy men of histamine and its metabolites, N tau-methylhistamine, imidazole acetic acid, and imidazole acetic acid conjugate(s), increased 1-3 h after food intake. The increase was seen even after the intake of konnyaku (mannan) as a protein-deficient food, suggesting that physical stimulation of the gastric mucosa by food is the main cause of histamine release. This suggestion was confirmed by the following findings in patients and mice. In patients with stomach diseases, gastrectomy resulted in decreases in the excretion of histamine and its metabolites in the urine, and patients subjected to intravenous hyperalimentation excreted less histamine and its metabolites in the urine than normal subjects. In mice, a correlation of histamine excretion with food intake was demonstrated experimentally. Namely, mice fed only during the night (21:00-0:00) showed increased excretions of histamine and its metabolites at 23:00-3:00, whereas those fed in the morning (9:00-12:00) showed increased excretions of those compounds at 11:00-15:00. All these results are consistent with the idea that urinary histamine and its metabolites mainly originate from the stomach.     

人工释放苜蓿切叶蜂的营巢行为观察

苜蓿切叶蜂Megachile rotundata Fabricius是紫花苜蓿的理想授粉昆虫,国内外已广泛利用切叶蜂为紫花苜蓿授粉,因此,对切叶蜂的田间活动行为分析具有重要的实践指导意义。对苜蓿切叶蜂的田间营巢行为进行观测,结果表明:整个花期切叶蜂均十分活跃,放蜂的第4天开始适应环境,正常活动,7月8～22日,切叶蜂最为活跃,进入蜂巢的切叶蜂数最高时达426头/蜂巢,每日10:00～16:00为活动高峰。每日每块蜂巢的封孔数最多为14个,平均每个蜂室封闭巢孔的数量最多为185个。     

Chewing activities and oesophageal motility during feed intake, rumination and eructation in camels

It was the aim of this study to characterize rumination behaviour, eructation and oesophageal motility in camels to identify similarities and differences between camels and domestic ruminants. Recordings were carried out in five camels fed on a hay-based diet. On an average, the duration of rumination, feeding and resting was 8.3, 5.6 and 10.1 h per 24 h, respectively. Rumination activity peaked in the morning between 9:00 and 11:00 and in the night between 02:00 and 04:00 a.m. During rumination periods, on an average 67 boluses were regurgitated per hour. Each bolus was chewed for an average of 45 s with 68 chews per min. The pause between two rumination cycles lasted on an average 9 s. Hay intake took 61 min/kg dry matter (DM), rumination lasted 71 min/kg DM of hay consumed. The regurgitation of a bolus started with a contraction of cranial compartment 1 (C 1) during a B-sequence, followed by a deep inspiration with closed glottis. Digesta enters the oesophagus, and an antiperistaltic wave transported the bolus orally. Eructation starts with a contraction of the caudal C1 during a B-sequence when the cranial C1 is relaxed. After entering the oesophagus, a rapid antiperistaltic wave transports the gas orally. Results revealed that the parameter values obtained in the camels were remarkably similar to those in domestic ruminants despite profound morphological differences and different patterns of forestomach motility.     

Daily rhythms of swimming activity,synchronization to different feeding times and effects on anesthesia practice in an Amazon fish species (Colossoma macropomum)

ABSTRACT

This study aimed to investigate the existence of day-night differences in the time for anesthesia and recovery in tambaqui exposed to the anesthetic eugenol and the influence of feeding time. Thus, we evaluated: (1) swimming activity; (2) food anticipatory activity (FAA) as a synchronizer of swimming activity and change to susceptibility to anesthetic; and (3) the effects of diurnal/nocturnal anesthesia exposure of fish feeding in the mid-light phase: 12:00 h (ML) and fish feeding in the mid-dark phase: 00:00 h (MD). Our findings revealed strictly nocturnal activity for tambaqui (94.2%), known as diurnal fish to date. Moreover, FAA was observed in tambaqui fed at MD, which showed a sustained increase in activity that began 2 h before feeding time and lasted until feeding. In contrast, no FAA was observed in fish fed at ML. Regarding anesthesia by day or night, the tambaqui treated with eugenol exhibited no difference in induction time. However, differences were observed in recovery times, with fish anesthetized at day recovering in 1–2 min and fish anesthetized at night recovering in 5–7 min. In short, our findings revealed for the first time the nocturnal behavior of tambaqui. These results indicated that recovery by day/night by eugenol in tambaqui has a strong dependence of behavioral patterns and the time of day.     

Time-dependent effects of leptin on food intake and locomotor activity in goldfish

The present study investigates the possible circadian dependence of leptin effects on food intake, locomotor activity, glycemia and plasma cortisol levels in goldfish (Carassius auratus). Fish were maintained under 12L:12D photoperiod and subjected to two different feeding schedules, one group fed during photophase (10:00) and the other one during scotophase (22:00). Leptin or saline were intraperitoneally injected at two different times (10:00 or 22:00), coincident or not with the meal time. To eliminate the entraining effect of the light/dark cycle, goldfish maintained under 24 h light (LL) were fed and leptin-injected at 10:00. A reduction in food intake and locomotor activity and an increase in glycemia were found in goldfish fed and leptin-injected at 10:00. No significant changes in circulating cortisol were observed. Those effects were not observed when leptin was administered during the scotophase, regardless the feeding schedule; neither in fish maintained under LL, suggesting that a day/night cycle would be necessary to observe the actions of leptin administered during the photophase. Changes in locomotor activity and glycemia were only observed in goldfish when leptin was injected at daytime, coincident with the feeding schedule, suggesting that these leptin actions could be dependent on the feeding time as zeitgeber. In view of these results it appears that the circadian dependence of leptin actions in goldfish can be determined by the combination of both zeitgebers, light/dark cycle and food. Our results point out the relevance of the administration time when investigating regulatory functions of hormones.     

Meal size and feeding management strategies influence the daily rhythm of total locomotor activity in horses (Equus caballus)

Keeping and management of horses can induce changes to instinctive and innate behavioural patterns. We investigated the effect of five different management conditions in five groups of horses. All groups were housed in individual boxes under natural environmental and lighting conditions. They were fed three times a day (07:00, 12:30 and 20:00) and had free access to water. Group A was fed with 8 kg/capo/die of hay divided in the three meals. Group B was fed with 8 kg/capo/die of an unifeed divided in the three meals. Group C was fed with unifeed at 07:00 and 12:30 and with hay at 20:00. They were kept in wood-bedded boxes. Groups D and E were fed with unifeed at 07:00 and 12:30, respectively, and in the other, two meals received hay. They were kept in straw-bedded boxes. Our results showed a daily rhythm of total locomotor activity in all groups, influenced by management conditions. Group A engaged in meal patterns similar to those seen in grazing animals. Groups B and C showed the highest MESOR values due to a high searching behaviour. Group C showed a nocturnal acrophase contrary to the other groups. Groups D and E showed a total locomotor activity pattern similar to that observed in Group A probably due to an increase in straw-bedding consuming. The reduction of fibre in diet has an impact on physiology and behaviour of horses. The valuation of diet and in bedding provided to horses kept in box is useful to guarantee the maintenance of the physiological daily rhythm of total locomotor activity.     

The Microflora and Concentrations of Volatile Fatty Acids in The Rumen of Cattle Fed on Single Component Rations

The composition of the rumen microflora and the volatile fatty acids were examined in cattle free-grazing on grass or stall-fed on hay, grass pellets, oats or dried beet pulp with molasses. Total and viable counts of anaerobic bacteria were highest on the grass feeding, but viable counts as a percentage of total counts were highest when oats or beet pulp with molasses were fed. Counts of cellulolytic bacteria were lowest on these latter 2 diets, and highest on grass or grass pellet diets. Studies of the anaerobic flora showed that the composition in animals fed on grass pellets resembled more that found in animals free-grazing on grass than in those fed on hay. Counts of aerotolerant bacteria were only a small percentage of the total count, but were highest on the hay diet. On this latter diet and on grass-feeding the streptococci (identified as Streptococcus bovis) were predominant, but contrary to expectation, streptococci were found only in small numbers on the oats diet, where coryneform rods were the major type present. Although a period of 4–6 weeks was allowed for the animals to adapt to the feeds, the 2 periods of feeding on oats and dried beet pulp with molasses markedly affected the composition of the rumen flora in the subsequent periods of feeding grass pellets and hay. Ruinen volatile fatty acid analysis showed a propionogenic effect of oats and the highest percentage of butyric acid when beet pulp with molasses was fed. The expected propionogenic effect of grass pellets was not observed.     

Day–Night Differences in Membrane‐Bound Pyroglutamyl‐2‐Naphthylamide‐Hydrolyzing Activity in Rat Hypothalamus,Pituitary, and Retina

Membrane‐bound pyroglutamyl‐2‐naphthylamide‐hydrolyzing enzyme activity was analyzed fluorometrically in the anterior hypothalamus, pituitary, and retina of adult male rats to investigate day–night differences. Six groups (n=6 per group) were assessed—three during the light span and three during the dark span—under a standard 12 h–12 h light–dark cycle (light on from 07:00 to 19:00 h) and controlled temperature environment, with food and water available ad libitum. In the hypothalamus, enzyme activity levels were higher for time points of the dark than the light period. In contrast, the pituitary and retina exhibited the highest levels at the time points of the light period. The pituitary and retina also exhibited significant differences between the clock‐hour means of the light period. Day–night differences in membrane‐bound pyroglutamyl‐2‐naphthylamide‐hydrolyzing activity may reflect differences in its susceptible endogenous substrates.