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The vitamins are a very important class of the nutrients. They play various important roles in the life cycle of any living-being. The absence or deficiency of the vitamins in poultry causes serious problems. The water soluble vitamins are very important sub-class of vitamins. In the poultry which can not synthesize these vitamins in their body these should be provided in the diets means these are dietary essential. The inclusion of the water soluble vitamins accurately, according to the needs of birds, production stage, physiological state of the birds and environmental conditions is very necessary to avoid the problems and to gain maximum performance because these vitamins are required by the birds in many systems including energy metabolism, growth, proper blood flow, development of skeleton, compensation of the stress, egg production, fertility, anti-oxidants for semen and proper development and viability of the growing embryos. It means these are not only important for current birds but also their provision in an accurate way will ensure the next generation of the birds.
Key words: roles, water soluble vitamins, poultry.
The term "vitamin" was first used in 1912. Vitamins are a group of complex organic compounds which are present in minute amounts in natural feedstuffs. These are required for normal metabolism and the deficiency of these compounds in the feed cause's deficiency diseases. The vitamins are divided into two groups depending upon their solubility i.e.:-
1) Fat soluble vitamins which include Vitamin A, D, E and K.
2) Water soluble vitamins which are Vitamin B-complex and vitamin C.
The names, synonyms and the two classes i.e. fat and water soluble can be summarized as:-
Retinol, retinal, retinoic acid
Vitamin PP, Vitamin B3
Pyridoxol, pyridoxal, pyridoxamine
Vitamin H, vitamin B8
Folacin, folate, Vitamin M, Vitamin Bc, Vitamin B9
(Adopted from McDowell, 2004)
Poultry and other monogastric animals are dependent on dietary sources of vitamins to a much greater degree than are ruminants. It is considered that animals with fully functional rumen can not suffer from a deficiency of vitamin B-complex. Vitamin B12 is unique in that it occurs in plant tissues as a result of microbial synthesis (McDowell, 2004). Thiamin (B1) is required to control appetite and reduces death rate, Riboflavin (B2) is responsible to control curly-toe paralysis, proper growth and proper egg production, Pantothenic acid(B5) is necessary for controlling dermatitis and improper lesions on the mouth and feet, Niacin(B3) is involved in proper confirmation of legs, tongue and mouth cavity, Choline ensures proper growth and proper egg production, Vitamin B12 is required to control anemia and to control early embryonic death, Folic acid(B9) is required for proper growth, controlling of anemia, proper feathering and proper egg production, Biotin (B8) is required to control dermatitis o feet, around eyes and beak and Ascorbic acid(vitamin C) is required to normal growth and development, growth and repair of tissues , formation of collagen, cartilage, bones, avoid stresses and wound healing (Unknown, 2002). Vitamin C (vit C) is a water soluble antioxidant found in cytosol and extracellular fluids and it can directly scavenge super oxide hydroxyl radicals and single oxygen species (Clarkson and Thompson, 2000). It is thought to exert its effects on the immune system through the enhancement of neutrophil production and through protection of the cell against super oxide radical damage (Bendich et al., 1986). Under normal conditions birds can synthesize sufficient amounts of vit C (Roy and Guha, 1958), however in the stress conditions birds may require an external source of vit C (Meade S.M. 2004) to provide non-specific resistance against infections and overcome stress and therefore improving productivity (Pardue and Thaxton, 1985). The phagocyte activity is enhanced in the presence of vit C. There is a higher quantity of the superoxides found in the phagocytes when sufficient amounts of vit C are found and further increase in the level of vit C further increases the amount of free radicals in phagocytes (Scarpa et al., 1983; Som et al., 1983). Viral infections have been shown to cause a depletion of leukocyte ascorbate, which resulted in varying degrees of non-specific immunosuppression and a reduction in serum vit C concentration (Thomas and Holt, 1978; Bendich et al., 1986).
The role of vit C in controlling of stress has been documented many a times. There was a proof that by providing external vit C source at a rate of 330ppm the blood levels of vit C are elevated (Nestor et al., 1972). Another study showed that a 1000ppm adding of vit C reduces exogenous cortisol related immunosuppression. Some studies have also reported that vit C decreases heat shock protein 70 and plasma corticosterone response in chicken subjected to cyclic heat stress (Mahmoud et al., 2003, 2004). Vitamin C supplementation in feed or water can also reduce the sensation of fear in the birds (Jones, R. B., 1996). Pardue and Thaxton (1986) documented the effects of supplementation with vit C on a number of characteristics including growth, reproductive performance, immunosuppression and mortality. It was also documented by Satterlee et al., 1989; Kutlu and Forbes, 1993a; McKee and Harrison, 1995)
Poultry under intensive production systems are particularly susceptible to vit deficiencies so to avoid this poultry feeds are supplemented normally with B2, niacin, pantothenic acid, B12 and choline out of water soluble vitamins (Scott et all. 1982). It is to be noted that Thiamin, vitamin B6, biotin and folacin are mostly present in adequate quantities in the major ingredients such as corn-soybean meal-based diets and poultry can normally produce a sufficient amount of ascorbic acid by its own (McDowell, L. R. 2004). Vitamin needs of new strains developed for improved production are higher. Leg problems seen in fast growing strains of broilers can be corrected in part by higher levels of biotin, folacin, niacin and choline (Roche 1979). Stress and disease conditions in animals may increase the basic requirement for certain vitamins. Nutrient levels that are adequate for growth, feed efficiency, gestation and lactation may not be adequate for normal immunity and for maximizing the animals' resistance to disease (Cunha 1985; Nockels et al. 1996). Diseases and microorganisms affecting the gastro intestinal tract reduce the absorption as well as the production of vitamins also the conditions affecting the G.I.T. cause a reduction in vitamin production and absorption i.e. diarrhea and vomiting(McDowell, L.R., 2004). Mycotoxins and internal bleeding in poultry also causes a reduced efficiency of vitamins (McDowell, L.R., 2004). Vitamin antagonists (antimetabolites) interfere with the activity of various vitamins (Oldsfield 1987). Under commercial production a higher level of the vitamins is helpful for optimum production and performance this also helps in achieving best growth rates, feed utilization and health and in part also helps to increase body reserves (Coelho, 1996). The ascorbic acid acts as an antioxidant for the avian spermatozoa (Surai et all, 2001). Ascorbic acid supplementation enhances the ejaculation qualities of male fowl (Surai et all, 2001). In the hot and dry season offering the cold water supplemented with ascorbic acid increases weight gain and spleen but it will also cause a reduced size of wings (Abioja, et all, 2011).
Classes of B-Complex:-
Based on the functions the B-complex can be categorized into 3 classes, however some of the members fall into more than one class;
Energy releasing- Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5), Piroxidine (B6), and Biotin.
Hematopoietic- Folic acid (B9), Cyanocobalamin (B12), Pantothenic acid (B5), and Piroxidine (B6).
Other- Thiamine (B1), Niacin (B3), Piroxidine (B6), Folic acid (B9), and Cyanocobalamin (B12). (Wilson, G. V.)
Vitamin B-complex deficiencies:-
Deficiency arises due to inadequate supplies of the vitamins and the signs develop over a time period. So if the vitamin levels provided are lower than the required levels then the classical deficiency signs will be seen in the birds. Generally the young and growing chicks are more prone to vitamin deficiencies and the developing embryo is the best model showing deficiencies of vitamins. Problems due to the B-complex deficiency arise quite abruptly and often seen in 5-7 days because there is a little storage of these in the body (Leeson, S. and J. D. Summers, 2001).
In the researches carried out on poultry of different age groups it was shown that a deficiency in the availability of Thiamine (B1) caused a loss of appetite and increased death ratios (Poultry Health Services, 2009). Leeson, S. and J. D. Summers, 2001 stated that polyneuritis in the birds shows the later stages of thiamine deficiency which may arise due to the build up of the intermediates of carbohydrate metabolism. In mature birds it is seen approximately 3 weeks after they are being fed a thiamine deficient feed. Poultry may also suffer from neuromuscular problems, resulting in impaired digestion, general weakness, star gazing and frequent convulsions (Leeson, S. and J. D. Summers, 2001).
A deficiency in the availability of Riboflavin (B2) caused increased occurrence in the curly toe paralysis, poor growth and poor egg production (Poultry Health Services, 2009). Many tissues especially epithelium and myelin sheath are affected due to feeding of a feed which is d4eficient in riboflavin and on postmortem the characteristic sign of riboflavin deficiency is marked enlargement of the sciatic and brachial nerve sheath with the sciatic nerve showing the most pronounced effects (Leeson, S. and J. D. Summers, 2001).
A feeding programme with a deficient amount of Pantothenic acid (B5) is evident as occurrence of dermatitis and lesions on mouth and feet (Poultry Health Services, 2009). According to Leeson, S. and J. D. Summers, 2001 the major lesions due to deficiency of pantothenic acid involve nervous system, the adrenal cortex and the skin.
Niacin (B3) deficiency is shown by bowed legs and inflammation of tongue and mouth cavity (Poultry Health Services, 2009). Leeson, S. and J. D. Summers, 2001 report that niacin deficiency is characterized by severe metabolic disorders of skin and digestive organs, signs being the loss of appetite, retarded growth, general weakness and diarrhea in the birds.
A feeding programme having deficiency of pyridoxine (B6) is characterized by retarded growth, dermatitis, convulsions, anemia and there may also be reduced nitrogen retention (Leeson, S. and J. D. Summers, 2001).
Choline deficiency is evident from poor growth, fatty liver, decreased egg production (Poultry Health Services, 2009). Leeson, S. and J. D. Summers, 2001 report the deficiency of choline in growing chicks is evident from poor growth and perosis.
Cobalamin (B12) deficiency is shown by cases of anaemia, poor growth, embryonic mortality (Poultry Health Services, 2009). According to Leeson, S. and J. D. Summers, 2001 a deficiency of B12 in growing chicks showed decreased weight gain, decreased feed intake, poor feathering and poor nervous system.
Folic acid (B9) deficiency is evident from poor growth, anaemia, poor feathering and poor egg production (Poultry Health Services, 2009). A deficiency of folic acid in the experimental birds caused macrocytic (megaloblastic) anemia and leukopenia i.e. reduced white blood cells (Leeson, S. and J. D. Summers, 2001).
Biotin (B8) deficiency increases the dermatitis on feet and skin around eyes and beak (Unknown, 2004; Poultry Health Services, 2009; Roche 1979; Leeson, S. and J. D. Summers, 2001).
The diseases and problem seen due to deficiencies of the water soluble vitamins in poultry can be summarized in the following table:-
Evident deficiency signs
loss of appetite
increased death ratios
curly toe paralysis
poor egg production
affected epithelium and myelin sheath
Pantothenic acid (B5)
lesions on mouth and feet
inflammation of tongue and mouth cavity
Loss of appetite
decreased egg production
Decreased weight gain
decreased feed intake
Poor nervous system.
Folic acid (B9)
poor egg production
dermatitis on feet and skin around eyes and beak
(Poultry Health Services, 2009; Roche 1979; Leeson, S. and J. D. Summers, 2001)
Role of water soluble vitamins as Co-enzymes:-
Riboflavin or vitamin B2 is a prosthetic part of over a dozen enzymes in the animal body including cytochromes reductase, lipoamide dehydrogenase, xanthine oxidase, L- and d-amino acid oxidase, histaminase and others all of which are vital for oxidation-reduction reactions involved in cell respiration (Leeson, S. and J. D. Summers, 2001).
Niacin or nicotinic acid is important in more than 100 different enzymatic reactions (Rasmusson R.) It is the vitamin component in two important enzymes i.e. nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) reported by Leeson, S. and J. D. Summers, 2001.
Pantothenic acid (B5) is the prosthetic group of coenzyme A, an important coenzyme involved in many reversible acetylation reactions in carbohydrate, fat and amino acid metabolism (Leeson, S. and J. D. Summers, 2001).
Biotin (B8) is an essential co-enzyme in carbohydrate, fat and protein metabolism (Leeson, S. and J. D. Summers, 2001).
Vitamin B12 is an essential part of several enzyme systems, with most reactions involving the synthesis of one carbon units i.e. methyl groups (Leeson, S. and J. D. Summers, 2001).
Role of Ascorbic acid (vitamin C) in birds under stressful conditions:-
The efficacy of supplementing birds with vitamin C under stressful conditions depends upon its ability to elevate plasma vitamin C (Pardue et al., 1984). Nestor et al., (1972) reported that 330ppm vitamin C elevated blood vitamin C. Pardue et al., (1984) reported that vitamin C supplementation at a rate of 250ppm increased plasma vitamin C concentrations in broilers. But Sell et all in 1997 found that 300 mg/kg vitamin C was unable to increase plasma vitamin C levels. Kolb (1984) strongly suggested that supplemental vitamin C should be provided in poultry and livestock diets as a stress alleviator. Hill and Garren (1958) agreed and stated that vitamin C was an essential nutrient in chickens experiencing stress. Vitamin C supplementation at 300 mg/kg was able to decrease plasma corticosterone in stressed birds. These responses are supported by research suggesting that vitamin C suppresses adrenocortical steroidogenesis and depresses plasma corticosterone levels, therefore limiting some of the deleterious responses associated with stress and delays the depletion of steroid hormone precursors (Pardue et al., 1985; Gross, 1992; Kutlu and Forbes, 1993). The action of vitamin C on adrenal steroidogenesis is associated with its ability to inhibit adrenal steroid hydroxylating enzymes (Kitabchi, 1967). Supplementation with 300 mg/kg of ascorbic acid resulted in a significant increase in plasma vitamin C throughout the experiment when compared to the "Un-Supplemented" birds (Meade, S.M., 2004). There is limited research examining the effects of vitamin C on lymphocyte subset populations in chickens. However, those experiments that have been demonstrated the effects of vitamin C on lymphocyte populations in association with disease or vaccination (Wu et al., 2000). The effect of dietary vitamin C supplementation is still controversial however vitamin C supplementation at 300 mg/kg alleviated stress-induced affects (Meade, S.M., 2004). These physiological and immunological findings suggest that vitamin C may be an anti-stress agent and may be an essential nutrient in poultry when poults are subjected to stressful conditions (Meade, S.M., 2004).
Ascorbic acid as an anti oxidant for avian spermatozoa:-
Ascorbic acid or vitamin c is water soluble anti oxidant present at high molar concentrations in spermatozoa and seminal plasma in a large number of animals. In poultry its concentration in semen averages 210 +-16.4microM (Surai et all 1986b). On a molar basis this concentration was more than 2.5 times higher than glutathione and more than 100 fold higher than alpha-tocopherol. Ascorbic acid was found almost equally distributed between spermatozoa and seminal plasma (Surai et all 1986b). This data was very useful in the development of an idea that vit. C plays an important role as a water soluble anti oxidant in the avian seminal plasma (Surai et all, 2001).
Ascorbic acid effect on ejaculation quality of male Fowl:-
Monsi and Onitchi in 1991 reported that fowl males housed under hot and humid conditions and supplemented with ascorbic acid showed a better overall ejaculation quality i.e. semen volume, motile sperm proportion and sperm number per ejaculate. The reported ascorbic acid supplementation level was 500mg/kg. However sperm motility was not affected. Dietary supplementations of ascorbic acid had the effects on semen of rainbow trout reflected by increased sperm motility and decreased decline in fertilizing capacity of spermatozoa after storage (Ciereszko and Dabrowski, 2000). A protective role of ascorbic acid in maintaining the sperm quality was also reported by Ciereszko and Dabrowski in 1996. However the low dietary levels of vitamin E and C (ascorbic acid) had no effects on the spermatozoa in mice rather the increased and higher supplementary levels decreased the number of spermatozoa/mg epididymis and increased the percentage of spermatozoa with misshapen heads (Ten et all, 1997).
Role of ascorbic acid in weight gain:-
A study was carried out in SW Nigeria on a group of broiler chicken. The birds were divided into four groups after the age of three weeks. A group was given cold water without any ascorbic acid and other group was given cold water with supplementation of ascorbic acid. Similarly two groups were made for normal unchilled water with and without ascorbic acid provision. The results of study showed a marked superior growth of breast meat and spleen in the group provided with cold water and ascorbic acid. However there was no affect of ascorbic acid supplementation on the growth parameters of the birds in any of the four groups. In addition there was a decreased wing length seen in these birds. The reason for this phenomenon to happen is that in hot climatic conditions a lot of the energy is wasted in panting and when cold water is provided the birds feel comfort and there is less panting seen. Also in stress corticosteroids are released which further decrease the weight gain. By providing cold water these both conditions are avoided so better results are obtained. The cold water resulted in an overall more weight gain weekly and finally more live weight however decreased wing length, the vitamin c had no effect on the growth however it increased the breast meat and the spleen in birds, (Abioja, et all, 2011).
Role of water soluble vitamins in Energy metabolism:-
The transformation of dietary energy sources, such as carbohydrates, fats and proteins into cellular energy in the form of ATP requires several micronutrients as coenzymes and cofactors of enzymatic reactions, as structural components of enzymes and mitochondrial cytochromes, and as active electron and proton carriers in the ATP-generating respiratory chain(Groff et all, 1996, Depeint et all, 2006): (i) thiamine pyrophosphate (TPP; vitamin B1), CoA (containing pantothenic acid), flavin mononucleotide (FMN; derived from vitamin B2), flavin adenine dinucleotide (FAD; derived from vitamin B2) and nicotinamide adenine dinucleotide (NAD; derived from nicotinamide) are involved in the Krebs cycle and complexes I and II of the respiratory chain; (ii) biotin, CoA and FAD are involved in haem biosynthesis, which is an essential part of the cytochromes and important for the latter part of the mitochondrial respiratory chain; (iii) succinyl-CoA can feed into either the respiratory chain or the Krebs cycle depending on the needs of the cell.
Depeint et all, in 2006 confirmed the essential role of vitamins B6, B12 and folate in maintaining the mitochondrial one-carbon transfer cycles by regulating mitochondrial enzymes. The same authors also emphasized the essential role of the B vitamin family in maintaining mitochondrial energy metabolism and how mitochondria in their role as the cellular organelles responsible for energy metabolism are compromised by a deficiency of any B vitamin (Depeint et all, 2006).
Table given here summarizes the present state of knowledge with regard to the role or roles of individual water soluble vitamins in energy metabolism (adopted from Institute of medicine, 1998).
Function in energy metabolism
â€¢ Essential cofactor in the conversion of carbohydrates to energy.
â€¢ Needed for normal muscle function, including the heart muscle.
â€¢ Involved in oxidative carboxylation reactions, which also require manganese ions.
â€¢ As a cofactor in the mitochondrial respiratory chain, helps in the release of energy from foods.
â€¢ Component of the main coenzymes FAD and FMN.
Nicotinic acid, niacin (B3)
â€¢ As a cofactor in the mitochondrial respiratory chain, helps in the release of energy from foods.
â€¢ Transformed into NAD and NADP, which play a key role in oxidation -reduction reactions in all cells.
â€¢ Helps in the release of energy from foods.
â€¢ Used as a cofactor by nearly 100 enzymatic reactions, mainly in protein and amino acid metabolism.
â€¢ Essential for metabolism of fats and carbohydrates and the synthesis of proteins.
â€¢ Interacts with folic acid metabolism.
â€¢ As a cofactor, involved in metabolism of fatty acids, amino acids and utilization of B vitamins.
â€¢ Plays an essential role in the Krebs cycle.
â€¢ Component of coenzyme A.
â€¢ Essential for synthesis of carnitine (transports long-chain fatty acids into
(Ascorbic acid) mitochondria) and the catecholamines, adrenaline and noradrenaline.
â€¢ Ascorbic acid facilitates transport and uptake of non-haem iron at the mucosa, the reduction of folic acid intermediates, and the synthesis of cortisol.
â€¢ Potent antioxidant.
â€¢ Folates function as a family of cofactors that carry one-carbon (C1) units required for the synthesis of thymidylate, purines and methionine, and required for other methylation reactions.
â€¢ Folate is essential for metabolic pathways involving cell growth, replication and survival of cells in culture.
â€¢ Around 30 - 50% of cellular folates are located in the mitochondria.
Toxicity arising due to water soluble vitamins:-
Toxicities arise due to over supplementation levels or more inclusion rates of the nutrients. Generally the toxicity of the water soluble vitamins is not seen in the birds because of the reason that these vitamins have a very minimal storage in the body. If the inclusion rate of vitamin B-complex is at least100x than the required level, it tends to cause toxicity in the poultry. Vitamin C, E and Biotin are moderately toxic, potentially causing problems at 20-30x the normal inclusion levels. Toxicity of vitamins administered in the drinking water is quite rare because the birds are reluctant to drink such fortified water (Leeson, S. and J. D. Summers, 2001).
From above discussion it can be concluded that the water soluble vitamins play many important roles in the poultry life including proper growth, production, weight gain, egg production, immunity, proper conformity, proper functioning, avoiding of stress due to many origins, proper feathering, proper skin condition and proper embryo development.
The water soluble vitamins are required in the metabolism, in the oxidation and reduction reactions as coenzymes which mean these are vital for the survival of the animals.
These also enhance the quality of the ejaculation in male fowl as well a act as antioxidants for the avian spermatozoa ensuring the fertility and avoiding deformities in the semen of poultry. The water soluble vitamin family member, ascorbic acid is also involved in extra gain of the breast meat which is most liked part of chicken meat in general.