Seaweed is a prominent resource in the various fields of biological applications. The present book depicts about the importance of marine algae utilization in various fields. They are the primary natural resources of the marine environment. Seaweeds have been of energy interest in the biomedical area, mainly due to their contents of bioactive substrates and they show great potential as anti-inflammatory, antimicrobial, antiviral, and anti-tumoral drugs. Due to their appropriateness as prospective feed production and as nutritional supplements, seaweeds are on the verge of becoming mainstream. Protein, dietary fibers, and phytochemicals found in seaweeds are utilized to improve the nutritional value of feed for animals. Since ancient times, animals in coastal regions have been fed seaweed, also known as marine algae. Seaweeds are used in animal feed since their consumption alone can be harmful to animals. this book is also discussed the seaweed applications using nanotechnology for the human drug development process. The nutritional benefits of seaweeds and their contributions to seaweed-based animal feed and supplements are discussed in this book.