Poultry diets based on grains, particularly corn, are routinely supplemented with pantothenic acid. For a practical corn-soybean meal diet, there was no effect of pantothenic acid supplementation for White Leghorn pullets 0 to 6 weeks of age (Bootwalla and Harms, 1991), for broilers aged 0 to 21 days (Harms and Nelson, 1992) or turkeys aged 0 to 4 weeks (Harms and Bootwalla, 1992b). However, although turkeys grew normally to 21 days without signs of pantothenic acid deficiency, increasing intake of pantothenic acid improved feed efficiency (Ruiz and Harms, 1989).
Scott et al. (1982) concluded that practical diets usually contain sufficient pantothenic acid for all classes of chickens, but a number of factors may influence the requirement for this vitamin. Increasing supplemental pantothenic acid to turkey breeding hens increased the transfer of pantothenic acid in eggs (Robel, 1993a). Scott (1966) indicated that the pantothenic acid requirement for poultry might have to be increased 60% to 80% due to a lack of availability from bound forms in feeds. Southern and Baker (1981) estimated that pantothenic acid in both corn and dehulled soybean meal was 100% bioavailable. The bioavailability of pantothenic acid in barley, wheat and sorghum, however, was estimated to be only 60% based on chick growth bioassay. Nevertheless, corn and sorghum contained less bioavailable total pantothenic acid than barley and wheat because of less total content of the vitamin. Clinical pantothenic acid deficiency signs appear to be completely reversible, if not too far advanced, by oral treatment or injection with the vitamin followed by restoration of an adequate level of pantothenic acid in the diet.
Type of diet influences need for pantothenic acid supplementation. High-protein diets reduce pantothenic acid needs due to the decreased level of dietary carbohydrate, which presumably would require coenzyme A for metabolism. Pigs fed a pantothenic acid-deficient high-fat diet failed to gain weight, exhibited a lower feed efficiency ratio and developed deficiency signs more quickly than pigs fed diets low in fat (Sewell et al., 1962). Biotin and folic acid have been found necessary for pantothenic acid utilization, and vitamin B12 and antibiotics have a sparing effect for chicks (Latymer and Coates, 1981) and pigs (Latymer et al., 1985).
Pantothenic acid is available as a commercially synthesized product for addition to feed. It is available as d- or dl-calcium pantothenate. One gram of d-calcium pantothenate is equivalent to 0.92 g of d-pantothenic acid activity. A racemic mixture (equal parts d- and l-calcium pantothenate) is generally sold to the feed industry. Because livestock and poultry can biologically utilize only the d-isomer of pantothenic acid, nutrient requirements for the vitamin are routinely expressed in the d-form.
Feed-grade pantothenic acid products are available in a number of potencies. Products that are sold on the basis of racemic mixture content can be misleading and confusing to a buyer who is not fully aware of the biologic activity supplied by d-calcium pantothenate. To avoid confusion, the label should clearly state the grams of d-calcium pantothenate or its equivalent per unit weight and the grams of d-pantothenic acid.
A straight racemic mixture is available to the feed industry, but its hygroscopic and electrostatic properties contribute to handling problems. Readily picking up moisture, it sticks to packing materials and feed manufacturing and processing equipment, and it can become hard after long exposure to air. Its electrostatic properties cause it to cling to metallic and other objects, and losses can be significant. Through complexing procedures, several companies now market free-flowing, essentially nonhygroscopic and nonelectrostatic products.
Verbeeck (1975) reported calcium pantothenate to be stable in premixes with or without trace minerals and regardless of the mineral form. Losses of calcium pantothenate may occur in premixes that are extremely acidic in nature, however. Use of a calcium pantothenate-calcium chloride complex instead of the plain calcium pantothenate should alleviate this problem.
There is controversy on the concept of removing vitamins and trace mineral supplementation from poultry and other species' diets sometime prior to slaughter. Skinner et al. (1992) reported that removal of vitamins and trace minerals from broiler diets did not affect performance. However, Teeter and Deyhim (1993) detected reduced performance and carcass variables when the same period was examined. Increased dietary fortification with pantothenic acid elevated (P < 0.05) pectoralis muscle concentration of the vitamin (Deyhim et al., 1992b). Such effects of removing vitamin supplementation have the potential to affect consumer perception of poultry meat as wholesome and should be considered when vitamin withdrawal is being contemplated.
