In the last article I discussed the fat soluble vitamins, namely vitamin A,D,E and K. This article will cover all the B vitamins and well as vitamin C. These fall into the water soluble group of vitamins. Again I will not be making recommendations on feeding levels, but rather have given a basic summary of each vitamin and the role it plays in the animal body. I have used the Nutrient Requirements of Swine (2012) as a reference.Biotin
Biotin is present in most feed ingredients at more than adequate amounts, however the availability varies greatly. It is important metabolically as a co-factor for several enzymes that function in carbon dioxide fixation. A considerable portion of the pig’s biotin requirement is presumed to come from the gut where it is synthesised by bacteria. Experimental results have been varied when looking at biotin supplementation and the effect on performance. Different biotin levels have been fed and yielded no improvement in rate or efficiency of gain in pigs weaned at 21 to 28 days of age, as well as in grower and finisher pigs. In sows, biotin supplementation was reported to improve hoof hardness and compression, reduce hoof cracks and footpad lesions and improve the condition of the skin and hair coat. Deficiency symptoms of biotin include skin ulceration and dermatitis, excessive hair loss, transverse cracking of the hooves, cracking / bleeding of the footpads and exudate around the mouth.
Choline is required for phospholipid synthesis, acetyl choline formation and the transmethylation of homocysteine to methionine (the latter occurs via betaine which is the oxidation product of choline). Soy products are rich in bioavailable choline which results in starting, growing and finisher pigs not showing significant responses to supplementation (to corn-soya diets). Supplementing choline to pregnant gilts and sows has resulted in an increase in the number of piglets born alive and weaned. Choline deficiency results in a reduced weight gain, decreased blood cell counts, rough hair coats, increased plasma alkaline phosphatase and unbalanced and staggering gaits.
This is the group of compounds with folic acid activity. Following studies the results have indicated that the folacin contribution of ingredients, together with bacterial synthesis within the intestinal tract adequately meet the requirement of the pig. Folacin deficiency symptoms are slow weight gain, fading hair colour, bone marrow hyperplasia, reduced haematocrit, macrocytic or normocytic anemia, thrombopenia and leukopenia. Sulpha drugs have been shown to reduce bacterial synthesis of folacin in the intestinal tract.
Niacin is a component of coenzymes NAD and NADP which are essential for carbohydrate, protein and lipid metabolism. The determination of niacin requirement has been complicated by the metabolic conversion of excess dietary tryptophan to niacin, as well as the limited bioavailability in some feed ingredients. Niacin in yellow maize, wheat, oats and sorghum is mostly unavailable to the young pig. Niacin deficiency signs include vomiting, decreased or lack of appetite, reduced weight gain, dry skin and rough hair coat, dry skin, hair loss, diarrhea, mucosal ulcerations, ulcerative gastritis and inflammation and necrosis of the cecum and colon.
Pantothenic acid is a component of coenzyme A which is important in carbohydrate and fat metabolism. The biological availability of pantothenic acid is low in wheat, barley and sorghum and high in maize and soyabean meal. Pigs with a deficiency of pantothenic acid may show signs of slow growth, alopecia, goose stepping, reduced immune response, dry skin and rough hair coat, diarrhea and inappetence.
Riboflavin is a component of FAD and FMN and is important in protein, fat and carbohydrate metabolism. Maize – soyabean meal diets are low in bioavailable riboflavin. In sows and gilts, a riboflavin deficiency has led to anestrus and reproductive failure. In growing pigs, deficiency signs are slow growth, stiffness of gait, vomiting, alopecia, cataracts and seborrhea.
Thiamin is an essential vitamin for protein and carbohydrate metabolism. Most grain – oilseed feeds are considered adequate in thiamine hence supplementation may not be required. Thiamine deficient pigs will show an appetite loss, reduced weight gain, reduced body temperature and heart rate and in some occasions, vomiting.
Vitamin B6 (The Pyridoxines)
Vitamin B6 plays an important role in the function of the central nervous system. A deficiency of Vitamin B6 results in reduced growth rate due to a reduced appetite. Serious deficiency will cause convulsions, coma, ataxia and death.
This vitamin contains the trace element cobalt in its molecule. Vitamin B12 is involved in the synthesis of methionine from homocysteine as well as the synthesis of DNA. Plants are devoid of Vitamin B12, but animal and fermentation by-products do contain this vitamin. Vitamin B12 is stored effectively in the body if consumed in excess. This results in a delay in onset of deficiency symptoms after a Vitamin B12 deficient diet is fed. Reduced weight gain, rough skin and hair coat, loss of appetite, hypersensitivity, irritability and hind leg incoordination are all signs of a vitamin B12 deficiency. Signs of folacin deficiency usually accompany vitamin B12 deficiency due to the later being required for folate metabolism.
Vitamin C is a water-soluble antioxidant involved in the oxidation of aromatic amino acids, the synthesis of carnitine and norepinephrine and in the reduction of cellular ferritin iron for transport to the body fluids. It also enhances the formation of bone matrix and tooth dentin. Vitamin C can be synthesized by the pig from D-glucose and other related compounds but under some conditions they may not be able to synthesize this vitamin rapidly enough to meet the requirement. Results from numerous experiments on vitamin C supplementation are inconsistent. It appears that if there is a need to supplement Vitamin C, it would be at times of stress where feed intake is limited.