Nutritionally optimal feeds for Asian Seabass or Barramundi

Asian seabass (Lates calcarifer) is an important finfish species for aquaculture in several

Countries across the world. Popularly known as Pandugappa in Andhra Pradesh and Betki in West Bengal, Seabass is an important potential fish species for farming in India as well. This is a euryhaline fish, growing rapidly up to 3-5 kg within a growing period of 2-3 years both in freshwater as well as brackish water environments. For maturation and spawning it migrates to the sea while the post-larvae and juveniles migrate to lagoons and backwaters for growth. It is a voracious carnivorous fish.

Seabass attains sexual maturity at the age of 3-4 years and at a length and weight range of 60 to 70 cm and 2.5 to 4.0 kg respectively. Males are generally smaller and in the size range of 2.0-3.0 kg and seabass being a protandrous hermaphrodite, males change sex and become females as they reach a size above 5.0 kg. The fecundity is between 2.1 to 17.0 million depending upon the size of the fish.

Availability of seed and appropriate feed are the two important prerequisites for the development and propagation of aquaculture of any fish species. In general, most marine carnivorous fish, including seabass require high dietary protein compared to omnivorous and herbivorous species. Therefore, fishmeal is being used as a major protein source in commercial formulations due to its balanced nutrients, essential amino acids and fatty acids, higher palatability and digestibility.

The nutritional requirements of fish vary with different growth stages and depend upon the feeding habits that change according to the morphology of the digesting system. Considerable effort has been made in Australia, Thailand, the Philippines and more recently in Israel in defining the nutritional requirements of this species to enhance production. Understanding the nutritional requirements of the candidate species is the first and essential prerequisite for the development of cost-effective, efficient and eco-friendly feeds: Diet preparation mainly focuses on energy nutrient requirements and micronutrient requirements such as vitamins as well as trace minerals.

Nutritional requirement in Initial stages (Hatchery or Nursery)

The nutritional requirements of larvae that have a body mass of less than a few milligrams are not very much understood. Based on the composition of the yolk, live prey and larvae themselves, it is assumed that the nutritional requirements of larvae were higher than those of the juveniles. The nutritional requirement is not similar for larvae and juveniles.

Protein: Protein sources were selected based on their amino acid profile and incorporated into the micro diet. Fish meal has been used as the main protein source in the diet. The profiles of essential amino acids in fish body tissue are generally considered as good indicator of their amino acid requirements.

Lipids: Lipids included in microparticulate diets come partly from fish meals or other meals incorporated as protein sources and are generally derived from marine sources. Cod liver oil, roe oil, sardine oil or menhaden oil are added as triglycerides in larval diets.

Nutritional factors affecting larval metamorphogemesis

Protein hydrolysate enhances larval morphogenesis. The molecular form of the dietary protein supply, native proteins or hydrolysed into oligopeptides (around

20 amino acids), which has probably an indirect effect on morphogenesis. Dietary lipids play an essential role in larval growth and survival. Growth and normal morphogenesis increased as the dietary inclusion of phospholipids and vitamins, particularly vitamin A.

Nutritional requirements for growers

Protein and amino acids constitute the key group of essential nutrients required by seabass for the synthesis of protein and subsequently growth.

Protein: Most of the studies undertaken to examine the requirements for protein in barramundi diets suggest a relatively high protein requirement due to the carnivorous/piscivorous nature of the fish. Seabass being highly carnivorous showed a dietary requirement of 45-55% protein. The diet energy density and the size of fish used, appear to be the key factors influencing the specific amount of protein required for seabass.

Amino acids: Most of the finfish including seabass show the requirement of the same ten amino acids (arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine tryptophan, tyrosine or valine) as essential.

Lipid: Lipids comprise an important dietary energy source for seabass and are also a source of essential fatty acids. Much work has been devoted to exploring the inclusion of lipids in barramundi diets to increase their energy density. The best growth rate has been observed in barramundi from diets having 45% to 50% protein and 15% to 18% lipid content.

Vitamins: It requires vitamins A, B, Riboflavin, Nicotinic acid, Cobalamin, Biotin, Inositol, Vit D, E, K and Vit C

About Skretting Stella B Seabass fish feeds

Skretting Nutrition is the global leader in producing aquafeeds across the globe having six Innovation and Validation centres across the regions and pioneers in innovating aquafeeds for different aquatic species, from marine hatchery feeds, broodstock feed and shrimp feeds, to high-value fish feeds and having 56 feed mills across the globe with its state-of-the-art manufacturing facilities.

Stella B (Seabass fish feed) is a high-quality and scientifically nutritionally balanced floating fish feed developed for Seabass. It contains an optimal blend of essential nutrients. Stella B is developed through extensive research and development in Skretting ARC (Norway). Moreover, it caters to the need for cage culture as well as rearing ponds. Our quality ensures maximum digestibility, and palatability and avoids any contaminant.