Vitamins are essential micronutrients, required for optimum health and normal physiological functions such as growth, development, maintenance and reproduction. Vitamins exercise catalytic functions that facilitate synthesis and degradation of nutrients, thereby controlling their metabolism and influencing poultry performance and quality of meat.
Most vitamins cannot be synthesized by animals and must therefore be obtained from feed. Although every animal should receive the right level of vitamins through feed, numerous factors impact the vitamin status, including storage times and limited bioavailability.
The vitamins A, K and C contained in feedstuffs, for example, can suffer a loss of activity of over half their content after six months of storage. At the same time, the bioavailability of biotin in most cereals is usually below 20 percent. On this basis, poultry manufacturers are increasingly looking at vitamin supplementation as a valid solution to increase vitamin intake.
Vitamin nutrition is an important aspect in the production and marketing of poultry meat and eggs, so its optimization is essential to maximizing return over feed costs. Vitamin requirements must be updated regularly to accommodate for improvements in production and marketing methods, changes in conditions on the farm, and new vitamin nutrition knowledge. Continued improvement of the genetic potential of poultry demands that the industry adapts to these changes and determines if increased vitamin levels are required to adequately meet these higher performance levels.
Changing world of poultry vitamin requirements
Although valuable guidance on minimum vitamin requirements can be obtained from the National Research Council’s (NRC) “Nutrient Requirements” publications, these alone are no longer adequate for commercial poultry rearing.
The NRC’s "Nutrient Requirements of Poultry" have been viewed as a nutritional benchmark since their first publication in 1944, but have been revised only eight times since then. Major advances in vitamin nutrition knowledge, improvements in vitamin product forms, and extensive changes in commercial broiler production have been taken into account, but the "Nutrient Requirements of Poultry" have not been updated in more than 20 years.
In that time, the poultry industry has advanced tremendously and faces new challenges and demands that were not foreseen or accounted for in 1994. For instance, layer feed conversion rates continue to improve year on year, but the NRC’s recommendations have not kept pace with that development. Furthermore, some experts feel the nutrient requirements need to be adapted as they are based on controlled studies and therefore often exclude the stresses encountered in a commercial environment.
The 13 vitamins currently required by the NRC account for approximately 33 percent of the total number of feed ingredients in many complete poultry rations. However, vitamins represent only a minute fraction of poultry feeds, amounting to less than 0.1 percent by weight and about 1 to 2 percent of the cost of poultry rations, depending on the diet used and the level of supplementation required.
Re-evaluating feed levels
Re-evaluating feed levels enables livestock producers to feed their animals high-quality vitamins in the right amounts and ratios, fitting to their life stage and growing conditions. Research has shown that performance benefits from optimized diets for meat production include increased growth, feed efficiency, oxidative stability of meat, resistance to high-density stress and prevention of bone problems.
For example, several research papers have demonstrated the effect of vitamin E in reducing lipid oxidation and improving meat quality and that supplementing diets with 25-OH-D3, the vitamin D metabolite, has been positively correlated with reduced incidence of lameness and other related bone defects, increased body weight, improved feed conversion and higher breast yield.
For laying hens, vitamin-optimized diets improve all phases of egg production, such as increased egg numbers, egg weights and percentage lay. Eggs and meat are excellent sources of bioavailable vitamins. Due to lower feed intakes as a result of improved feed efficiency, vitamin levels have decreased in meat and eggs in recent years. Use of balanced concentrations in poultry feeds will improve human nutrition as poultry products will be a dependable source of bioavailable vitamins.
To account for the advances in the production of poultry meat and eggs, optimum vitamin intake is required as a cost-effective method to optimize animal health, well-being, performance and the quality and nutritional value of these products. For the modern successful poultry operation, balanced nutrition is essential and, in order to achieve this, livestock producers need to check regularly the vitamin levels in their feed.