Vishwajit S. Chowdhury

Gonadotropin-inhibitory hormone (GnIH), a neuropeptide that inhibits gonadotropin synthesis and release, was first identified in quail hypothalamus. GnIH acts on the pituitary and GnRH neurons in the hypothalamus via GnIH receptor to inhibit gonadal development and maintenance. In addition, GnIH neurons express melatonin receptor and melatonin induces GnIH expression in the quail brain. Thus, it seems that melatonin is a key factor controlling GnIH neural function. In the present study, we inves

Birds reduce their food intake by the exposure to high ambient temperature (HT) which ultimately affects their productivity. However, physiological and behavioral responses of young chicks of different ages to HT have not yet been investigated. In this study, we examined the effects of HT (40, 4-h) in 3-, 5-, 7-, 14-and 21-d old chicks. There were no significant differences in food intake between heat exposed and control chicks up to 7-d old, while clear suppressions of food intake were observed

Some amino acids are important regulators of key metabolic pathways and necessary for several physiological functions. However, little is know about thermoregulatory functions of amino acids. In this study, therefore chicks were either centrally or orally administered with L-citrulline (L-Cit), L-arginine (L-Arg) or L-ornithine (L-Orn) to monitor changes in rectal temperature. In Experiment 1, the amino acids (L-Cit, L-Arg and L-Orn) were administered into the left ventricle of the chicks by int

The existence of RFamide peptides with a C-terminal LPXRFamide (X=L or Q) motif has been identified in the brain of various vertebrate species. However, the presence of LPXRFamide peptides in the urodele brain is not yet known. In this study, we cloned a cDNA encoding the precursor of LPXRFamide peptides from the newt brain by a combination of 3' and 5' rapid amplification of cDNA ends. The deduced LPXRFamide peptide precursor consisted of 233 amino acid residues, encoding four putative LPXRFami

With global warming, heat stress is becoming a pressing concern worldwide. In chickens, heat stress reduces food intake and growth, and increases body temperature and stress responses. Although it is believed that young chicks do not experience heat stress as they need a higher ambient temperature to survive, our series of studies in young chicks showed that they are sensitive to heat stress. This review summarizes current knowledge on amino acid metabolisms during heat stress, with special emph

Increased average air temperatures and more frequent and prolonged periods of high ambient temperature (HT) associated with global warming will increasingly affect worldwide poultry production. It is thus important to understand how HT impacts poultry physiology and to identify novel approaches to facilitate improved adaptation and thereby maximize poultry growth, health and welfare. Amino acids play a role in many physiological functions, including stress responses, and their relative demand an

An experiment was conducted to analyse the changes in free amino acid concentrations in the blood, brain and muscle of chicks in response to 15 or 30 min exposure to high ambient temperature (HT). Food intake and body weight were not affected, while rectal temperature was significantly increased by short-term HT exposure. Several free amino acid concentrations increased in the blood, brain and muscle even with short-term HT, whereas levels of a few amino acids declined significantly. As well as