Impact of growth trajectory on sexual maturation in layer chickens.

Recent studies showed that apart from photostimulation, metabolic triggers may independently activate sexual maturation and egg production in chickens. However, the origin, mode of action, and specific target(s) of this metabolic control remain unknown. Beyond body weight (BW), we hypothesize that body composition (BC) and associated specific metabolic signals are involved.

Oral Administration of a Medium Containing L-Citrulline-producing Live Bacteria Reduces Body Temperature in Chicks.

Recently, we showed that oral administration of crystallized L-citrulline (L-Cit) caused hypothermia under a control thermoneutral temperature (CT) and provided thermotolerance under high ambient temperature (HT) in chicks. The aim of this study was to clarify whether oral administration of a medium containing L-Cit-producing live bacteria can reduce body temperature in chicks under CT. In Experiment 1, 7-day-old chicks were orally administered either a medium (containing mainly L-Cit-producing live bacteria and 277 mM L-Cit) or an equimolar amount of L-Cit to determine their effects on body temperature (acute treatment).

Cortisol responses of goldfish (Carassius auratus) to air exposure, chasing, and increased water temperature.

Fish can respond to stimuli from the internal or external environment with activation of the hypothalamo-pituitary-interrenal (HPI) axis and the secretion of cortisol. Stimuli that activate the HPI axis of fish include short term air exposure and increases in water temperature. The present study was conducted to determine how quickly cortisol concentrations increase in goldfish subjected to an increase in water temperature, and to compare the response to an increase in water temperature with responses to other stimuli.

Reduction in voluntary food intake, but not fasting, stimulates hypothalamic gonadotropin-inhibitory hormone precursor mRNA expression in chicks under heat stress.

Heat stress is an issue of rising concern across the globe. Recently, we found that mRNA expression of gonadotropin-inhibitory hormone (GnIH), an orexigenic neuropeptide, was increased in the heat-exposed chick brain when food intake was reduced. The aim of the current study was to examine mRNA expression of GnIH and of the glucocorticoid receptors (GRs) in the hypothalamus as well as the plasma corticosterone (CORT) and metabolites in 14-d-old chicks exposed to a high ambient temperature (HT; 40 ± 1 °C for 1 or 5 h) or a control thermoneutral temperature (CT; 30 ± 1 °C), either with free access to food or fasted.

Central NPY-Y5 sub-receptor partially functions as a mediator of NPY-induced hypothermia and affords thermotolerance in heat-exposed fasted chicks.

Exposure of chicks to a high ambient temperature (HT) has previously been shown to increase neuropeptide Y (NPY) mRNA expression in the brain. Furthermore, it was found that NPY has anti-stress functions in heat-exposed fasted chicks. The aim of the study was to reveal the role of central administration of NPY on thermotolerance ability and the induction of heat-shock protein (HSP) and NPY sub-receptors (NPYSRs) in fasted chicks with the contribution of plasma metabolite changes.

L-Citrulline acts as potential hypothermic agent to afford thermotolerance in chicks.

Recently we demonstrated that L-citrulline (L-Cit) causes hypothermia in chicks. However, the question of how L-Cit mediates hypothermia remained elusive. Thus, the objective of this study was to examine some possible factors in the process of L-Cit-mediated hypothermia and to confirm whether L-Cit can also afford thermotolerance in young chicks.

Central administration of neuropeptide Y differentially regulates monoamines and corticosterone in heat-exposed fed and fasted chicks.

Recently, we demonstrated that brain neuropeptide Y (NPY) mRNA expression was increased in heat exposed chicks. However, the functions of brain NPY during heat stress are unknown. This study was conducted to investigate whether centrally administered NPY affects food intake, rectal temperature, monoamines, stress hormones and plasma metabolites in chicks under high ambient temperatures (HT).

l-Leucine acts as a potential agent in reducing body temperature at hatching and affords thermotolerance in broiler chicks.

Thermal manipulation (TM) of incubation temperature causes metabolic alterations and contributes to improving thermotolerance in chicks post hatching. However, there has been no report on amino acid metabolism during TM and the part it plays in thermotolerance. In this study, we therefore first analyzed free amino acid concentrations in the embryonic brain and liver during TM (38.

Chronic oral administration of pine bark extract (flavangenol) attenuates brain and liver mRNA expressions of HSPs in heat-exposed chicks.

Exposure to a high ambient temperature (HT) can cause heat stress, which has a huge negative impact on physiological functions. Cellular heat-shock response is activated upon exposure to HT for cellular maintenance and adaptation. In addition, antioxidants are used to support physiological functions under HT in a variety of organisms.

L-Ornithine is a potential acute satiety signal in the brain of neonatal chicks.

Recently, we observed that neonatal chicks exhibit feeding behavior characterized by frequent food intake and short resting intervals, with changes detected in the brain amino acid and monoamine concentrations. In this study, we aimed to clarify further the relationship between the appetite of neonatal chicks and brain amino acid metabolism. In Experiment 1, changes were investigated in free amino acids in the brain under conditions of regulated appetite induced by fasting and subsequent short-term re-feeding.

Acute heat stress up-regulates neuropeptide Y precursor mRNA expression and alters brain and plasma concentrations of free amino acids in chicks.

Heat stress causes an increase in body temperature and reduced food intake in chickens. Several neuropeptides and amino acids play a vital role in the regulation of food intake. However, the responses of neuropeptides and amino acids to heat-stress-induced food-intake regulation are poorly understood.