Right for Animals

The goal of RIGHT for ANIMALS is preventative care by getting it right for vitamins at the right stage and by strengthening the immune system to minimize the risk of the animal getting sick, reducing the need for treatment of weakened or diseased animals. Good nutrition is one of the most important factors helping to keep animals healthy: We know that when people eat heathy diets, take vitamin and mineral supplements, their immune systems are strengthened, and the same benefits apply for animals

What vitamins do

Vitamin have been divided into two groups based on their solubilities in water or in fat. B-complex vitamins and vitamin C are classified as water soluble while the fat-soluble vitamins include A, D, E and K. The eight different types of B vitamins (thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid, and cobalamin) each have unique functions in the body as coenzymes or cofactors in~ ~intermediate metabolism related to boosting energy and reducing stress (Fig. 1). Fish are unable to synthesize vitamin C because they lack the enzyme Lgulonolactone oxidase in the pathway and herefore it must be supplied to fish through the feed with a precise estimate of optimal requirements using bioavailable forms (Holt, 2011).

Vitamin have been divided into two groups based on their solubilities in water or in fat.

Fat soluble vitamins are absorbed mainly in intestinal tract and stored in the body’s fatty tissues and are necessary in small doses. Vitamin A (Retinol, retinal, retinyl esters) is important as a dietary supplement for all animals and plays role in two aspects, vision and gene expression regulation promoting growth and cell development. Vitamin D (Cholecalciferol or vit D3; Ergocalciferol or vit D2) is involved in regulation of growth and differentiation of various cell types and it has role in controlling plasma calcium and phosphorus. Vitamin E (tocopherols and tocotrienols), serves as an important antioxidant (Fig.2) and it is important for growth, fertility, reproduction and immune system. Vitamin K (Phylloquinone or vit K1; menaquinone, or vit K2; menadione or vit K3) play vital roles in blood coagulation and aids bone mineralization in fish. All 15 vitamins have been demonstrated to be metabolically essential for all fish species and must be obtained through the diet to maintain normal growth, reproduction and health of fish.

Are your animals getting enough vitamins to stay healthy? How much do you know about vitamin requirements for your animals?

Why are vitamins important for your animals? Growth rates, reproductive efficiency and especially immune system function can be directly and indirectly effected by vitamin nutrition. When it comes to getting the right amount of vitamins in feeds, it is generally accepted that the requirements for vitamin differ for various species, breeds, production stage, age, and size. Various studies indicate that the vitamin levels recommended in Nutrient Requirements of Fish and Shrimp (NRC 2011) do not appear to be adequate because of many influencing factors; e.g., higher vitamin levels may be required in some stages, deficiencies of some vitamins may occur when substituting ingredients, loss of some vitamins during feed production, and finally, changing requirements due to farming conditions, water quality, stress and handling.

Influence of life stage

During maturation, brood stock have higher vitamin requirements to reach high fecundity, prolong spawning, improve quality, hatchability, viability of eggs and larvae than levels required for normal growth of typical farmed animals. The retention of essential nutrients such as essential fatty acids and Vitamin C by eggs and larvae are dependent on the nutrient reserves in the brood stock, consequently larval seed quality increases when improving the quality of brood stock nutrition. In male fish, it has been observed that high vitamin E supplementation (720.6 mg/kg), significantly improved sperm concentration, duration of motility and maintained normal sperm morphology of turbot (Xu et al., 2015). Other research with milkfish has confirmed the essentiality of vitamin C (1000 mg/ kg), alone or in combination with vitamin E (500 mg/kg) in producing more spawns with higher egg and larval quality (Emata et al., 2000). The supplementation of 400 mg/kg of vitamin E during the reproductive period of female Nile tilapia is sufficient to ensure the best reproductive performance, providing efficient production of a larger number of larvae in individuals of this species (Nascimento et al., 2014).
Furthermore, early stages of larval development are more sensitive to nutrient deficiencies than in later developmental stages because younger fish larvae have rapid growth rates, but have less efficient digestive systems and lower storage capacity of vitamins in their organs.
For example, water soluble vitamins are poorly stored in organs and tissues, which means that excessive intake leads to rapid tissue saturation and increased excretion (Holt, 2011). Larval production of red sea bream with supplementation of vitamin C at a level of 800 mg/ kg (Ren et al., 2010) or with vitamin E at 3 g/kg (Atalah et al. 2008) has been shown to produce high quality larvae which have greater tolerance under stressful conditions than controls without vitamin supplementation.
Dietary thiamin requirements are proportional to animal age and size as well as physiological conditions that increase the metabolic rate. Juveniles are more susceptible to vitamin B1 deficiency due to their rapid metabolism and lack of storage capacity (McDowell, 2000). Furthermore, it is important to be aware of fluctuations of vitamins supplied in live life stage-diets. Folic acid improves the antioxidant capacity of aquatic animals and an optimum dietary folic acid level has been estimated at 2.29-2.90 mg/kg for juvenile Chinese mitten crab (Eriocheir sinensis) (Wei et al., 2016), and 0.82-1 mg/kg for juvenile tilapia (Shiau and Huang, 2001, NRC, 2011).

Dietary interactions

many factors; ingredients, feed characteristics, vitamin forms, feed manufacturing and storage conditions, bioavailability, biological variations, environment factors, etc. Due to limited availability of marine ingredients as well as sustainability concerns, many studies have been conducted on replacing all or part of fishmeal in aquafeed with plant based-ingredients and other alternative ingredients. It is not a simple matter to take fishmeal or other types of animal proteins out of feed formulations. It is very important that any nutrient gaps resulting from fish meal reduction are closed. Shifting feeds away from marine and animal ingredients to terrestrial ingredients increases the risk that nutritional deficiencies will occur. Consequently as the composition of the diet changes, the contribution of endogenous vitamins will also change with specific vitamins varying among ingredients. Nutritional concerns regarding plantbased diets include meeting adequate levels of vitamin D, B2, niacin, pantothenic acid, B6 and B12 (Hansen et al., 2015). For example, signs of a pantothenic acid deficiency were observed within 6 weeks when rainbow trout were fed a plant-based diet with or without vitamin premix. Among all supplemented diets, vitamin premix signi?cantly improved survival, feed intake, protein retention ef?ciency, energy retention effciency, hematocrit and hepatosomatic index (Barrows et al., 2018).

Shiau and Shiau (2001) reported that the dietary vitamin E requirement of hybrid tilapia increased as the dietary lipid level increased.

Several studies on the interaction between macronutrients and vitamins have found that vitamin levels should be adjusted in parallel with changing nutrient content. It has been shown that vitamin B6 (pyridoxamine) is involved in protein metabolism (Lewicki et al., 2018), and when dietary protein levels were increased in diets for tilapia, the pyridoxine requirement increased from 4 mg/kg to 12-50 mg/kg (Shiau and Hsieh, 1997). Shiau and Shiau (2001) reported that the dietary vitamin E requirement of hybrid tilapia increased as the dietary lipid level increased. Similar results were found with grouper, where the optimum dietary vitamin E requirements increased from 61-68 mg/kg to 104-115 mg/kg as the dietary lipid level increased from 4% to 9%, respectively (Lin and Shiau, 2005). Dietary polyunsaturated fatty acid content is another factor impacting dietary vitamin E requirements in fish, with evidence showing that elevation of unsaturated fatty acid levels can result in increased requirements for vitamin E as intracellular antioxidants to protect cells (Fig. 1). In red sea bream (Pagrus major), compared to controls, an increase of supplementary a-tocopherol > 100 mg/kg and dietary vitamin C > 400 mg/kg could improve growth performance and reduce lipid peroxidation and blood oxidative stress status (Gao et al., 2012a; Gao et al., 2013). Recently, the development of nutritional strategies using highenergy diets for fast growing strains have shown increased nutritional needs for essential nutrients like amino acids, vitamins, lipids and minerals. Vitamin supplementation of highenergy diets must be increased substantially because animals will consume less feed, thereby reducing vitamin intake. Diet composition is another factor that can influence the thiamin requirement. Thiamin has key functions in intermediate carbohydrate metabolism converting carbohydrates into cellular energy (Fig 1), so the requirement increases as consumption of carbohydrate increases.

Other functions of thiamin include: 1) Acting as an antioxidant, where it is oxidized by free radicals and hydroperoxides; 2) Acting as a hydrogen donor converting NADP+ to NADPH which has strong reducing potential supporting regeneration of glutathione (Fig. 2); 3) Thiamine diphosphate is required as a co-factor for transketolase activation in the pentose phosphate pathway. (Lukienko et al., 2000; Surai et al., 2003). These functions of thiamin help to explain why thiamine deficiency has been observed in salmon eggs when spawning salmon brood stock have been fed a high lipid, PUFA rich diet: Thiamin intake is insuffcient in proportion to the dietary supply of energy and unsaturated fatty acids such a diet provides (Keinänen et al., 2018). Indeed, we can assume that thiamin and vitamin E levels should be adjusted upwards for optimum performance of any marine brood fish fed a high lipid PUFA-rich diet.

Farming conditions and handling

Under practical farming conditions, vitamin supplementation levels first need to consider requirements by species, sexual maturity and size. However, under certain stressful conditions, vitamin supplementation needs to be increased. Intensive culture often increases susceptibility of fish and shrimp to diseases which then then lead to mass mortality. Therefore, it is important to develop functional feeds and improve farm management strategies to reduce stress and improve immunity in aquatic animals.
Researchers have reported that dietary supplementation with high levels of vitamin C and E can reduce stress, improve immune response and disease resistance of fish species (Verlhac et al., 2015; Izquierdo and Betancor, 2015). A study with carp reared in laboratory tanks showed that sufficient amounts of vitamin C, B1 and B6 supplements were able to protect the fish from the effects of mild handling stress (Jakab Sandor et al., 2017). Silver pomfret fed a diet with dosages of vitamin C at 450 an 800 mg/kg had better cortisol regulation and a higher survival rate during a transportation stress test than pomfret fed low vitamin C (Peng et al. 2013). Moreover, dietary supplementation with 500 mg/kg vitamin E has been reported to improve HSP70 mRNA levels, raise antioxidant capabilities, increase resistance to crowding stress, and improve growth in Wuchang bream (Megalobrama amblycephala) (Liu et al., 2014). The dietary supplementation of pyridoxine at 100 mg/kg diet enhances growth, antioxidant activity and reduces thermal stress in Indian major carp (Labeo rohita) fingerlings reared in high water temperature (33?C) comparing with in ambient temperature (26?C) (Akhtara et al., 2012)

However, under certain stressful conditions, vitamin supplementation needs to be increased.

In spite of climatic constraints and limitation of water in some areas, low-salinity inland culture of white-leg shrimp is common and widespread in many regions. White shrimp have the ability to grow and survive in low salinity environments, however feed vitamins have to be optimized to accommodate shrimp production under this environmental condition.
Vitamin C and E can help white shrimp to adapt to a low salinity environment by improving their antioxidant status (Li et al., 2015) and enhancing SGR and survival rate during acute salinity stress (Darvishpour et al., 2012) Likewise, vitamin D3 supplementation of approximately 6,400 IU/kg in low salinity water has been shown to improve calcium deposition in the exoskeleton, important for successful molting (Wen et al., 2015). Vitamins are considered essential nutrients in fish/shrimp feeds which improve growth performance, feed efficiency, health status, stress tolerance and resistance to diseases.
Unfortunately, there is still much that is unknown in relation to changing to more sustainable terrestrial ingredients, different life stages, variability of farming conditions, etc. With better research and preparation, we can identify the critical vitamins in each case, and determine the most effective levels to maintain optimal feed performance and growth against these influencing factors. Maintaining optimized vitamin levels in finished feeds is cost effective when measured against the improved performance and immune status under all farming conditions.

Practical vitamin supplementation to Asian fish and shrimp feeds

The DSM Aquaculture Center Asia-Pacific has prepared preferred practical vitamin supplementation levels for Asian freshwater fish (carp, catfish, pangasius and tilapia) and marine shrimp species (Wilson 2019).
1Amount to be increased by 30% for fry, larva and broodstock, 2At low stock density the lower are recommended, 3The upper for low salinity rearing, 4Conversion Factors: 1000 IU Vitamin A (Retinol) = 0.344 mg vitamin A acetate 1000 IU, 5Vitamin D3 (cholecalciferol) = 0.025 mg vitamin D3.
The recommended vitamin amounts stated are those which should be provided to the animal in the feed at the point of consumption. Additional vitamins should be added to the product to account for processing and shelf-life storage losses to achieve the targeted consumption amounts of vitamins. To ensure optimum vitamin nutrition at all times, DSM recommends that vitamin levels in feeds be assessed regularly by every feed mill, and DSM offices can provide access to analytical services for vitamins on customer request.