Fish Genetics And Endocrinology

During the past two decades, fish endocrinology has witnessed exciting developments due to our increased knowledge at all levels of biological organizations, including molecular biology, cell biology, physiology and behavior. New insights into development, neurobiology, immunology and molecular genetics closely correlated with classical aspects of endocrinology and represent important contributions to our knowledge on regulatory processes of vertebrates, including fish. The purpose of this book is to overview major advances in numerous research areas of fish endocrinology. Most of the chapters not only review and discuss the state-of-the-art in the respective field, but also show perspectives of future research. The book will be of interest to scientists involved in basic fish research, comparative endocrinology, fisheries and aquaculture as well as for students of fish biology.

Provides an overview of major advances in numerous research areas of fish endocrinology. This book is useful to scientists involved in basic fish research, comparative endocrinology, fisheries and aquaculture as well as for students of fish biology.

This book is dedicated to present different aspects of reproductive physiology and molecular endocrinology of commercially important as well as potential aquaculture fish species. The existing aquaculture generation is looking for species diversification for efficient utilization of available diverse water resources. The knowledge of reproductive physiology of fish will help in development of breeding strategy for use in commercial aquaculture. Reproductive system is highly coordinated and governed by means of complex network of nervous, endocrine system and environmental factor as well. This book emphasize on different key aspects of reproductive endocrine system such as basic gonadal biology in the events of climate vulnerability, sex determination, sex reversal, stimulatory hormones, inhibitory hormones and receptors, environmental and chemical factor guiding reproduction, puberty, neuroendocrine regulation of reproduction etc. This book further describes how reproduction is not just indispensable for the existence or survival of an individual, but it is important for the survival of species. Chapters also address the concerns of anthropogenic activities on fish and the aquatic environment lead main trouble on physiological and reproductive processes of aquatic animals. This book offers an attractive compilation of highly relevant aspects of current and future of aquaculture, especially in view of the growing awareness of aquaculture, to food scientists working on commercial fish, animal biologists, fish geneticists etc. This book is very timely, and relevant to the sustainable development goals. The contents would be relevant to policy makers, working towards blue revolution and blue economy.

Of all vertebrates, fish exhibit unparalleled diversity of sexual plasticity and flexibility, ranging from gonochorism to unisexualism, and exceptional patterns of functional hermaphroditism. Fish farming and monosex aquaculture have led to reproductive dysfunction with males producing less milt, and females failing to ovulate and spawn. This book

Hormones have a manifold impact upon growth and metabolism. This book focuses upon the molecular biology of fish hormones and their regulation. Chapters dealing with gonadotropin, corticotropin, vasotocin, isotocin, somatolactin, and other hormones are written by an international team of fish physiologists and endocrinologists. In addition, there are chapters that survey a growing literature on the ways hormones are regulated both in terms of their actions and in terms of the gene transcription that leads to their formation. The first two sections of the book covers brain and pituitary hormones and the latter two sections are devoted to other hormones and their regulation. As more and more endocrinologists and physiologists seek to use hormones that are inexpensive, provide for more facile experimental replication, and are less subject to cumbersome regulation, they will turn to the sorts of fish models reviewed in this book.

Growth rate is a primary trait of interest in most finfish selection programs and is intrinsically linked to productivity and profitability of finfish aquaculture industry in several parts of the world. Search for candidate genes influencing growth has been a major focus of research in aquaculture and several such genes have been isolated from the fish genome and their effects are quantified. Growth hormone genes have been studied extensively in many species because of its potential in enhancing the growth rate of fishes in aquaculture. The identified growth hormone gene in most of the fishes is roughly 1.5 kb long, with the protein coding region divided in to four to five blocks (exons) representing less than one third length of the genomic region. Growth hormone (GH) is a single chain polypeptide that plays a major role in the growth development of vertebrates. It is the main regulator of postnatal somatic growth and stimulates anabolic processes such as cell division, skeletal growth and protein synthesis. In addition, growth hormone is also involved in the regulation of fat oxidation, inhibition of glucose transport to peripheral tissues and regulation of ribosome translational activity, which in turn influences protein synthesis. Presently, the importance of GH as a candidate gene for studies of genetic variation in connection with growth traits and potential natural marker for studies of evolutionary relationship of various fishes has been demonstrated. Its potential application in the growth traits and fish evolution studies has been an active area of research. Natural growth rates of organisms have evolved to provide maximum fitness in wild environments and therefore, enhancement of natural growth rate of fish in aquaculture has been extensively explored, with gains arising from improvements in husbandry, nutrition, and genetical selection. Growth enhancement can be advantageous for aquaculture by shortening production time, and enhancing feed conversion efficiency. Therefore, endocrine approaches in controlling growth have been extensively explored. Several studies have demonstrated the efficacy of mammalian GH in the acceleration of growth of various species. In fish, GH administration by various modes of delivery like injection, and oral administration of hormones has been successfully studied. These studies have suggested that the exogenous growth hormone enhances fish growth by stimulating appetite and improving feed conversion. It is clearly understood that growth hormone plays major role in aquaculture industry by increasing the growth. Therefore, knowing the different aspects of growth hormone is very much essential for the researchers aim for growth enhancement in fishes.