| Abstract: | Studies on vitamin B6 and pantothenic acid conducted with pigs, poultry and veal calves are presented to demonstrate the difficulties involved in research on B vitamins. The analysis of the B vitamins already poses problems, so that recommendations on dietary requirement must be seen in the light of the respective analytical procedures used. A distinction must be made between the minimum and optimum requirements of the animals. Today, the dietary provision of the optimum requirements is of priority and needs suitable and sensitive biochemical criteria or performance criteria for assessment.Studies using early-weaned and market pigs demonstrate that, in the case of vitamin B6, the urinary xanthurenic acid secretion after a tryptophan load and the activities of the serum transaminases are suitable biochemical criteria to diagnose suboptimum supply. Though these criteria were less responsive in poultry than in pigs, nevertheless, when the supply of vitamin B6 was suboptimal in broiler chicken, the body's retention of dry matter, nitrogen and energy, providing measures of true performance, proved to be affected adversely.The assessment of the optimum vitamin B requirement for practical feeding rations is illustrated with results from studies on the pantothenic acid requirement of broilers and market pigs. On the basis of live weight gain and feed efficiency, and also taking into consideration biochemical criteria provided by pantothenic acid and coenzyme A levels in the blood and liver, an optimum pantothenic acid requirement of 8 mg per kg of feed is recommended for broilers and 9 mg per kg of feed for market pigs. The dietary requirement of piglets, market pigs and broilers for vitamin B6 is estimated to be 3 mg per kg of feed. |
