Role of Vitamin-C and Multivitamin Diets for Enhacement of Immunity, Growth and Biological Performance in Shrimps/ Fishes

Good nutrition in aquaculture systems is essential to economically produce a healthy and high quality  product. Vitamins are essential nutrients found in foods. They perform specific and vital functions in a variety of body systems and these are crucial for maintaining optimal health. Vitamins are a heterogeneous group of organic compounds essential for the growth and maintenance of aquatic animal life. The majority of vitamins are not synthesized by the fish body or at a rate sufficient to meet the aquatic animals needs.

Vitamins are distinct from the major food nutrients (proteins, lipids, and carbohydrates) in that they are not chemically related to one another. They are present in very small quantities within animal and plant foodstuffs. They are required by the fish body in trace amounts. Approximately 15 vitamins have been isolated from biological materials and their essentiality depending on the species, the growth rate of the animal, feed composition, and the bacterial synthesizing capacity of the gastro-intestinal tract of the animal. In general, all fish display distinct morphological and physiological deficiency signs when individual vitamins are absent from the diet.

The two different types of vitamins are Fat-soluble vitamins and Water-soluble vitamins.

Fat-soluble vitamins dissolve in fat before they are absorbed in the bloodstream to carry out their functions. Excesses of these vitamins are stored in the liver, and are not needed every day in the diet.The fat-soluble vitamins are absorbed from the gastrointestinal tract in the presence of fat and can be stored within the fat reserves of the body whenever dietary intake exceeds metabolic demands .

Fat soluble: Vitamin A1 (Retinol, retinal, retinoic acid), Vitamin A2 (Dehydroretinol), Vitamin D2 (Ergocalciferol), Vitamin D3 (Cholecalciferol), Vitamin E (Tocopherol, tocotrienols), Vitamin K1 (Phylloquinone), Vitamin K2 (Menaquinone), Vitamin K (Menadione)

Water-soluble vitamins dissolve in water and are not stored by the body. Since they are eliminated in urine and require a continuous daily supply in fish/shrimp diet. Water-soluble vitamins are easily destroyed or washed out during food storage or preparation. Body stores being rapidly depleted in the absence of regular dietary water-soluble vitamin sources.                                                                       

Water Soluble:  Thiamin (Vitamin B1), Riboflavin (Vitamin B2), Niacin  (Vitamin B3) Vitamin B6 (Pyridoxol, pyridoxal, pyridoxamine), Pantothenic acid (Vitamin B5) Biotin (Vitamin H, vitamin B8) , Folic acid (Vitamin M, Vitamin Bc, Vitamin B9) Vitamin B12 (Cobalamin), Choline (Gossypine), Vitamin C ( Ascorbic acid)                                                                                                             

Thiamine (B1) : aids growth, digestion, fertility, nervous system, carbohydrate metabolism and oxidation of glucose

Riboflavin (B2): vision, enzyme functioning ,energy metabolism, respiration of poorly vascularised tissues, metabolism of carbohydrates, fats and proteins.

Pyroxidine (B6): enzyme secretion , protein and carbohydrate  metabolism.

Pantothenic Acid (B5): adrenal functioning, cholersterol production, normal physiology and metabolism ,

Nicotinic Acid (niacin, B3) : lipid, protein and amino acid metabolism

Biotin (H): enzyme secretion, purine and lipid synthesis, oxidation of lipids and carbohydrates,

Folic Acid (M): blood cell formation, blood glucose regulation and various metabolism

Cyanocobalamin (B12): enzyme systems, cholesterol metabolism

Inositol:  cell membrane permeability, structural component of skeletal, heart and brain tissue, growth of liver and bone marrow cells, liver lipid (cholesterol) transport, synthesis of RNA.

Choline: better growth and FCR, maintenance of cell structure and the transmission of nerve impulses, transport of lipid within the body. 

Retinol(Vitamin A): highest biological activites, normal vision, form a visual pigments, maintenance of the mucous secreting epithelial tissues of the reproductive tract, skin, bone and gastro-intestinal tract, protecting mucous membranes and developing bone tissue, epithelial cell metabolism, release of proteolytic enzymes from lysosomes.

Cholecalciferol (Vitamin D) : calcium and phosphorus metabolism,  growth of bone tissue, synthesis of the calcium binding protein, the conversion of organic phosphorus to inorganic phosphorus in bone, maintenance of blood calcium level, and the deposition and oxidation of citrate in bone.

Tocopherol: act as lipid-soluble extracellular and intracellular antioxidants, protect the highly unsaturated fatty acids, important role in cellular respiration, biosynthesis of DNA and coenzyme Q.

Phylloquinone (Vitamin K): maintenance of normal blood coagulation, electron transport and oxidative phosphorylation in micro-organisms

Vitamin C probably is the most important because it is a powerful antioxidant  and immunomodulator for fishes/ shrimps. The fish and shrimp body needs vitamin C( ascorbic acid or ascorbate) to remain in proper health condition.

Water temperature: Vitamin C diets  helps to fishes during  low temperature period for  enhancing digestion efficiency and thereafter promote growth rate.

Stress : The ascorbic acid concentrations in tissues in fish change during stressful periods Vitamin C prevents from various stress such as: environmental stress, handling stress, pathogenic stress, transportation stress, osmotic stress etc,  of fishes and  shrimps.

Toxic Gasses Eliminator: The ascorbic acid helps to eliminate the adverse effect of ammonia on growth of fishes  and reduces the toxic effect of nitrite levels in intensive aquaculture systems.

Wound healing: Vitamin C makes collagen formation  in body and helps in quick  for optimal wound repair in fishes and shrimps.

Reproduction: Vitamin C helps in reproduction systems of fishes and shrimps such as growth of healthy brooders, proper egg and sperm formation, optimum fecundity, improve hatchability, healthy larval and fry conditions etc.

Larval Nutrition: Diet with vitamin C  acts fast development of embryo /larvae and early fry stages with reduction of mortality in early stages of fishes /shrimps.

Immunity: Vitamin C is at the top of the list among natural immune boosters for fish /shrimp body.Vitamin C have the immune-stimulating properties and compensate the immune-depression. It offers protection to fish / shrimp immune system by encouraging the activity of immune system cells including neutrophils and phagocytes. The collagen prevents various  diseases caused by bacteria and viruses  . Mucus helps in preventing microorganisms from entering to the body through the skin, gills and gastrointestinal mucosa. Vitamin C  prevents bacteria from adhering to epithelial cells. High concentration of vitamin C in white blood cells enables the immune system to function properly by providing protection against oxidative damage from free radicals generated during their action against bacterial, viral, or fungal infections.

The dietary vitamin requirements of fish and shrimp have been determined by feeding graded levels of each vitamin. Most fishes and shrimps, the quantitative dietary vitamin requirements will depend upon a number of important factors including:

In contrast to the fat soluble vitamins (A, D, E and K), the water soluble vitamins can be readily lost from the feed through leaching prior to ingestion by the fish. In general, the smaller the feed particle size and the longer the feed remains uneaten in water, the greater the loss of water soluble nutrients. L-ascorbic acid (vitamin C) has been found to be particularly prone to loss through leaching.

The use of feed antibiotics to treat disease outbreaks may destroy the vitamin synthesizing capacity of the gut microflora of fish which in omnivorous/ herbivorous species may play an important role toward the vitamin requirements of the animal.

In contrast to the water soluble vitamins, fish and shrimp accumulate fat soluble vitamins under conditions where dietary intake exceeds metabolic demand. Under certain circumstances accumulation is such that a toxic condition (hypervitaminosis) may be produced.                             

VitaminToxicity signs : Reduced growth and haematocrit, severe necrosis/erosion of anal, caudal, pelvic and pectoral fins, scoliosis, lordosis, increased mortality, pale yellow livers,lethargy, dark colouration, poor feed efficiency, Reduced blood erythrocyte concentration

RIBOFLAVIN: Anorexia, poor growth, corneal vascularisation, cloudy lens, spinal deformities, severe fin erosion, fin haemorrhage, rapid opercular movement, apparent muscular weakness, light or dark pigmentation, photo- phobia, lethargy, anaemia                                                              

NIACIN :Anorexia, poor growth, reduced feed efficiency, dark colouration, erratic swimming, muscular spasms while resting                                                                                                                                       

PANTOTHENIC ACID: Anorexia, reduced growth, gill necrosis/clubbing, high mortality, pale gill and liver, anaemia, mucous covered gills, sluggish, opercules distended                                                                           

THIAMINE: Anorexia, poor growth, dark colouration, mortality                                                              

PYRIDOXINE: Nervous disorders, hyperirritability, anorexia, ataxia, erratic and rapid swimming, greenish-blue colouration of skin, anaemia, rapid and gasping breathing                                           

BIOTIN : Anorexia, reduced growth, increased mortality, poor feed efficiency, blue-slime disease (brook trout only), lesions in the colon, thick gill lamellae, pale gills                                                                              

FOLIC ACID: Anaemia, poor growth, anorexia, lethargy, dark colouration, pale gills and liver, exopthalmia, distended abdomen with ascites fluid                                                                                                          

VITAMIN B12 : Anorexia, reduced growth, anaemia, fragmented erythrocytes, poor feed efficiency, dark pigmentation                                                                                                                                                     

CHOLINE :Reduced growth, fatty liver, poor feed efficiency, haemorrhagic kidney and intestine                                                                                                                                            

INOSITOL: Reduced growth, distended abdomen, dark colour, skin and fin lesions/haemorrhages, loss of skin mucosa ,increased gastric emptying time                                                                                                    

VITAMIN C: Reduced growth, internal/fin haemorrhage, distorted/twisted gill filaments, poor wound repair, increased mortality rate, reduced egg hatchability, Black death syndrome (blackening of exoskeleton; melanized haemocytic lesions), reduced wound repair and feed efficiency, poor growth and survival                                                                                                                                                               

VITAMIN A: Reduced growth, exopthalmia, depigmentation, clouding and thickening of corneal epithelium, degeneration of the retina, Anorexia, faded body colour, fin and skin haemorrhages, exopthalmia, abnormal/warped gill operculae                                                                                            

VITAMIN D: Reduced growth and feed efficiency, anorexia, tetany, elevated liver/muscle lipid content and plasma, Reduced survival rate                                                                                                                           

VITAMIN K: Increased blood clotting time, anaemia, haemorrhagic gills, eyes, vascular tissue, Skin haemorrhages                                                                                                                                                          

VITAMIN E: Reduced growth, exopthalmia, ascites, anaemia, clubbed gills, epicarditis, ceroid deposition in spleen, increased mortality, pale gills, erythro- cyte fragility, muscle damage/degeneration, reduced egg hatching rate/spawning efficiency, Reduced survival