Timekeeping is important at two levels: to time changes in physiology and behavior within each day year. For the former, birds have a system of least three independent circadian clocks present retina eyes, pineal gland, hypothalamus. This differs from situation mammals which input, pacemaker, output are localized different structures. Each bird clock interacts with one other clock, together, they appear form centralized that keeps daily time. These powerful endogenous component, light‐dark...

Human bowel movements usually occur during the day and seldom night, suggesting a role for biological clock in regulation of colonic motility. Research has unveiled molecular physiological mechanisms function brain; less is known about peripheral rhythmicity. This study aimed to determine whether genes such as period 1 (per1) period2 (per2) modulate rhythmic changes Organ bath studies, intracolonic pressure measurements, stool studies were used examine measures motility wild-type per1per2...

When confined to a cage, migratory songbirds exhibit nocturnal restlessness (also called Zugunruhe) during the spring and autumn periods, even though these birds are exclusively diurnal remainder of year. Zugunruhe, which has been demonstrated be under direct control circannual timer, is characterized by stereotypic “wing-whirring” behavior while bird perched. To elucidate role played circadian system in regulation authors studied activity garden warblers ( Sylvia borin), long-distance...

Regulation of the daily rhythm milk synthesis is important to production animals and breastfeeding, but difficult observe in nursing animals. The rate food intake varies over day expected create a nutrient absorption. objective this study was determine if timing entrains pattern synthesis. Seventeen Holstein cows were used crossover design. Treatments ad libitum feeding total mixed ration once (1× fed) or fed four equal meals every 6 h (4× fed). Cows milked last 7 days each period. There...

Avian behavior and physiology are temporally regulated by a complex circadian clock on both daily an annual basis. The secretion of the hormone melatonin is critical component regulation circadian/daily processes in passerine birds, but there little evidence that gland regulates changes primary reproductive function. Here it shown locomotor rhythms house sparrows, Passer domesticus, which made arrhythmic either pinealectomy or maintenance constant light, can be synchronized administration...

Dairy cows display daily rhythms of milk synthesis that appear to be driven by a circadian clock located in the mammary gland. These are altered time feed availability. Fatty acids have been shown entrain liver and adipose tissue experimental models, but their role gland has not well investigated. Our objective was determine effects timing fatty acid absorption on synthesis. Nine lactating Holstein were arranged 3 × Latin square design. Treatments abomasal infusions 350 g/d free stock...

Fruit preference by birds is a complex process based upon the morphology and spatial arrangement of fruits on physiological needs capabilities birds. In North America, most can be divided into two groups nutritional content: those rich in sugars relative to lipids, lipids sugars. To investigate how fruit may change seasonally determine if it correlated with state, we designed simple laboratory experiment using American Robins (Turdus migratorius) artificial fruits. During summer autumn,...

Laying hens often experience unbalanced calcium utilization which can cause deficiencies in bone and egg mineralization. Because melatonin has been shown to affect mineralization other animals, we examined whether treating with would eggshell thickness improve skeletal performance, thereby reducing shell defects. Birds were given a diet containing either low (30 µg/kg), medium (300 or high (3 mg/kg) concentrations of melatonin, control feed through approximately one laying cycle. We the...

White-throated sparrows increase fat deposits during pre-migratory periods and rely on these stores to fuel migration. Adipose tissue produces hormones signaling factors in a rhythmic fashion may be controlled by clock adipose or driven master the brain. The convey photoperiodic information from environment facilitate fattening, may, turn, release adipokines indicate extent of energy stores. Here, we present evidence that change signal adiponectin visfatin act body condition, thereby...

Abstract Many birds undertake long biannual voyages during the night. During these times of year drastically reduce their amount sleep, yet curiously perform as well on tests physical and cognitive performance than non-migrating year. This inherent physiological protection disappears when are forced to stay awake at other year; thus protective changes only associated with nocturnal migratory state. The goal current study was identify mechanisms that confer against consequences sleep loss...

Temporal changes of mRNA expression three clock genes, qPer2, qPer3 and qClock, were studied in the suprachiasmatic nucleus (SCN) Japanese quail under different light conditions, as well condition continuous melatonin. In addition, melatonin receptor Mel1a Mel1c, SCN also examined. The qPer2 showed robust oscillation during both dark (LD) 12:12 cycles constant conditions (DD), but did not exhibit circadian rhythmicity (LL), instead being expressed at a consistently high level. Expression LD...

The amplitude of the b-wave electroretinogram (ERG) varies with a circadian rhythm in green iguana; is high during day (or subjective day) and low night night). Dopamine melatonin contents eye are robustly rhythmic under constant conditions; dopamine levels day, night. affect an antagonistic phase-dependent manner: D2-receptor agonists injected intraocularly produce high-amplitude b-waves characteristic whereas reduces amplitude. Sectioning optic nerve abolishes rhythms content. results this...

The circadian system of the lizard Iguana iguana is composed several independent pacemakers that work in concert: pineal gland, retinae lateral eyes, and a fourth oscillator presumed to be located hypothalamus. These govern expression multiple behaviors physiological processes, including rhythms locomotor activity, endogenous body temperature, electroretinogram, melatonin synthesis. numerous, easily measurable rhythmic outputs make an ideal organism for examining contributions individual...

Circadian physiology in the vertebrate retina is regulated by several neurotransmitters. In lateral eyes of green iguana circadian rhythm melatonin content peaks during night while dopamine day. present work, authors explore interaction these 2 neurotransmitters cycle. They depleted retinal with intravitreal injections 6-hydroxydopamine (6-OHDA) and measured ocular vivo throughout 1 The not only persisted but increased 10-fold amplitude. This increase was substantially reduced intraocular...

Serotonin in blood plasma is primarily synthesized the duodenum, as brain derived serotonin does not cross blood-brain barrier. Because and retina under control of a circadian clock, we sought to determine if clock duodenum regulates synthesis release blood. We examined gene expression chickens at different times day found that rhythmically expresses molecular genes controlling biosynthesis, specifically tryptophan hydroxylase, light dark cycle (LD). Analysis showed amount varies across...

Abstract Exposure to stressors over prolonged periods can have fitness‐relevant consequences, including suppression of immune function. We tested for effects presence an invasive species threat on a broad panel functions coexisting lizard. Eastern fence lizards ( Sceloporus undulatus ) been exposed fire ants Solenopsis invicta 80 years. Fire sting and envenomate lizards, causing physiological stress, but we do not comprehensive understanding the consequences lizard exposure ant presence....

Milk synthesis exhibits a daily rhythm that is modified by the timing of feed intake. However, it unknown how specific nutrients entrain this rhythm. Amino acids have an important role in milk synthesis, and may entrainment mammary circadian rhythms. The objective study was to determine effects intestinally absorbed protein on rhythms component key plasma hormones metabolites. Nine lactating Holstein cows were assigned 1 3 treatment sequences × Latin square. Treatments included abomasal...

Dairy cows have a daily pattern of feed intake which influences ruminal fermentation and nutrient absorption. Milk synthesis also exhibits rhythm is altered by the timing availability. Nutrients can regulate physiological rhythms, but it unclear specific nutrients affect rhythms milk in cow. The objective this study was to determine effect acetate infusion on intake, synthesis, fatty acids, plasma insulin metabolites, core body temperature. Ten lactating ruminally cannulated Holstein (127 ±...