Preface

Comparative endocrinology is an important component of animal physiology. Hormones influence animal physiology and behavior. Knowledge gained from studies in the hormonal biology of animals can be applied to the health management of diverse systems including production animals, wildlife species, and humans.

The contributing authors come from diverse science disciplines; herein they have applied comparative endocrinology approaches to the study of fundamental and applied areas such as aquaculture, livestock production, and human health management. The texts incorporated in the book are an attempt to provide a range of comparative endocrinology studies from crustaceans, rodents, ruminants, to humans. Each chapter author has provided robust datasets to support the research discussion and outcomes. The book will be useful to students of biological and biomedical sciences and to comparative physiologists, researchers, and clinicians.

The editor is thankful to every individual who helped in the preparation of this book, and he is indebted to the chapter contributors for accepting helpful criticism, resulting in the present shape of the book.

Last but not least, the editor thanks Ms. Manuela Gabric and Ms. Dajana Pemac, publishing process managers at IntechOpen, for sending information and guidelines that allowed this book's chapters to be edited well on time.

> **Dr. Edward Narayan** School of Science and Health, Western Sydney University, New South Wales, Australia

**1**

**Chapter 1**

Science

**1. Introduction**

*Edward Jitik Narayan*

affective) state of animals [7, 8].

its environment [12, 13].

**2. Stress endocrine response**

stores and to restore homeostasis [16].

Introductory Chapter:

Applications of Stress

Endocrinology in Wildlife

Conservation and Livestock

Animals have contributed towards the progress of mankind in many ways such as through biomedicine, scientific research, domestication and farming, zoo animals and aquaculture [1–5]. The key concept of animal welfare underpins the quality of life of an animal while living under human management [6]. Animal welfare is a complex subject which takes into account the environmental and management factors that influence the physiological, behavioural and emotional (well-being or

Animals such as elephants, dolphins, birds and dogs can display complex cognitive ability guided by processes such as perception, learning, memory and decisionmaking [9, 10]. Emotion in animals involves complex physiological, behavioural, immune, cognitive and morphological responses that enable them to generate behaviours to cope against stressors [11]. There are specific physiological markers of pain and stress that enable researchers to evaluate the welfare of animals from a quantitative viewpoint and relate the data to understand how the animal perceives

Disruption to an animal's homeostasis initiates activation of the hypothalamicpituitary-adrenal (HPA) axis (**Figure 1**), the result of which generally prepares the body for some form of exertion [14, 15]. The hypothalamus releases corticotrophinreleasing hormone (CRH) [15], signalling the anterior pituitary to release adrenocorticotrophic hormone (ACTH) [15], which circulates in the blood resulting in an increased output of glucocorticoids from the adrenal cortex. Glucocorticoids, in which cortisol is pivotal to larger vertebrates and fishes, while corticosterone occurs mainly in birds, amphibians and reptiles, act to partition energy through gluconeogenesis, in preparation for a physical challenge, by diverting storage of glucose away from glycogen/fat and mobilising glucose from stored glycogen. Following the stress response, cortisol acts to initiate PH balance, as a blocker within a negative feedback process to CRH secretion, and motivates the animal to replenish energy

## **Chapter 1**
