Essay On Fish Culture

INTRODUCTION The victory of fish culture relies on optimization of food consumption and maximization of production in a cost-effective manner. Feed is a fundamental need that is necessary for life of all animals including fish. Underfeeding or lack of feeding may even lead to death of fish. Feed is the most luxurious part occupying 40-60% of the total input cost in aquaculture industry depending on the method of production (Marimuthu et.al., 2010). Efforts have been made to ensure the maximum feed utilization by fish in various ways by usage of mixed feeding timetable of varying high/low dietary protein levels in feed and addition of digestive enzymes in the diet. Overfeeding is also followed sometimes to ensure maximum growth, but it often leads to wastage of feeds and fatal economic and health related issues. Hence, the fish producers and researchers are constantly looking out the new

In fish it is predominantly secreted by the stomach (Sakata et al., 2002), but is also synthesized in the brain (Cowley, 2003). Ghrelin consist of 28 amino acid residues with an acyl side chain attached to the serine residue at third position. This acyl group is crucial for ghrelin´s orexigenic and GH-releasing actions. The term ghrelin is based on the hormone’s role as a growth hormone-releasing peptide. Ghrelin is also called as the growth hormone secretagogue (GHS) receptor. Ghrelin seems to play an important role in the short-term as well as long-term regulation of food intake and body weight (Kaiya et al., 2008; Kojima and Kangawa, 2005). Ghrelin is believed to convey information about nutrient availability from the stomach to the brain (van der Lely et al., 2004; Cummings et al., 2005). Ghrelin originates in the periphery and signal to the brain, mainly to the hypothalamus and thereby ensuring maximum feeding and body weight gain (Saito et al.,