Apelin and Its Physiological Role in Regulatory Feed Intake in Fish (Labeo rohita)
Ishita Bhardwaj
*
Department of Biosciences, University Institute of Biotechnology, Chandigarh University, Mohali, Punjab,140301, India.
Kamal Vatika
Department of Biosciences, University Institute of Biotechnology, Chandigarh University, Mohali, Punjab,140301, India.
*Author to whom correspondence should be addressed.
Abstract
Bioactive peptide apelin is essential in animals for the control of energy balance and the maintenance of feeding behaviour. It was studied in Labeo rohita, Cirrhinus mrigala, Silver carp etc., a widely cultured freshwater fish species in regulation of food intake. The review compiles findings that investigated apelin in different tissues and in interaction with hunger regulatory hormones to uncover the action of apelin in feeding process. We found that apelin and its receptors are expressed throughout the body, including in the brain, and so are likely to be involved in hunger and satiety regulation. Synthetic apelin was able to alter feeding behaviour and key hormones ghrelin and leptin that respectively control appetite/energy utilization. Also, fasting and refeeding experiments revealed that apelin levels change with the nutritional state of the fish, suggesting it plays a role in adjusting feeding responses to ensure that fish adapt to food, as determines its availability. These insights give apelin a key role as a feeding and growth regulator in aquaculture species. The mechanisms by which apelin affect fish farming efficiency and sustainability could be understood, which could ultimately lead to new approaches to optimize feeding strategies of fish farm to improve the efficiency and sustainability of fish farming.
Keywords: Hunger regulation, eating patterns, feed efficiency, metabolic processes, apelin peptide