Quantitative Requirement for Cholecalciferol in the Absence of Ultraviolet Light

Abstract

Studies were conducted to determine the basic requirement of the bird for cholecalciferol in the absence of ultraviolet light by utilizing filter sleeves on fluorescent lights in the room and brooder. In Experiment 1, some pens were fitted with filter tubes and some lights were turned off. All the birds received a cholecalciferol-deficient diet. Birds with ultraviolet light excluded grew slowly, developed rickets (95%), had low plasma calcium, and low bone ash (27%); whereas birds exposed to the fluorescent light had normal growth and plasma calcium, slightly low bone ash (38%), and some rickets (12%). Experiments 2 and 3 were conducted to determine the amount of cholecalciferol that must be added to the diet under conditions in which ultraviolet light was excluded. In Experiment 2, the highest level of cholecalciferol fed was 400 ICU/kg. This level was not sufficient to permit the chickens to have weight gain or bone ash equal to the birds receiving the ultraviolet light. The birds receiving 400 ICU/kg of diet also had a 77% incidence of rickets compared with 20% for the birds receiving ultraviolet lights. In Experiment 3, when birds received 800 or 1,600 ICU/kg of cholecalciferol in the diet, they grew and were comparable to those receiving ultraviolet light for the criteria measured.

Use of vitamin D to reduce lameness in broilers reared in harsh environments

“…The authors concluded that the vitamin D 3 requirements of broilers up to 14 d of age are much higher than earlier estimates and may be related to the higher calcium requirements of the modern broiler genotypes. The results of the present study are also in agreement with the conclusions obtained by other investigators who, using diets with unbalanced Ca: P levels to induce TD, observed a reduction in the leg disorders when using, in particular, the active metabolite 1,25-dihydroxyvitamin D 3 (Rennie et al, 1993;Edwards Jr. et al, 1994, 2000Fritts & Waldroup, 2003). It is likely that, when TD is induced by hypocalcaemia or vitamin-deficient diets, this condition may be secondary to rickets, which might be mitigated by correcting calcium homeostasis.…”

“…Broilers had access to natural lighting and indirect UV light, as it is the case of most broiler houses in Brazil, which may have enhanced the vitamin D status. Several authors (Edwards Jr. et al, 1994;Edwards Jr., 2003) established the optimal doses and methods of secure use of UV light to chicks to increase their vitamin D status under laboratory conditions. This may provide an alternative to supplying high levels of vitamin D in the starter diets.…”

“…In contrast with all other vitamins, vitamin D is endogenously produced in the skin exposed to UV light, and several studies indicated that UV light is effective in reducing leg problems in chickens (Ameenuddina et al, 1985;Edwards Jr. et al, 1994;Elliot & Edwards Jr., 1997;Edwards Jr., 2003). Edwards Jr. (2000) found that broilers fed diets deficient in vitamins, minerals, and amino acids are more susceptible to leg problems.…”

Vitamin D3 requirement of young chicks receiving diets varying in calcium and available phosphorus

“…Edwards et al (1994) and Elliot and Edwards (1997), however, concluded that at least 20 m g D3/kg was required from 1 to 16 d of age when exposure of chicks to uorescent lighting was prevented. The chicks in our studies were con ned to batteries containing no lighting, but overhead uorescent lights were present on a continuous 24 h basis.…”

Efeito da vitamina D3 e 25-hidroxi-colecalciferol sobre o desempenho, o rendimento de carcaça e a morfologia intestinal de frangos de corte¹

“…As exigências para máximo desempenho normalmente são menores que 25 μg/kg ração (Edwards et al, 1994;NRC, 1994). A fase inicial, período em que ocorre alta taxa de crescimento do tecido esquelético, além da imaturidade do trato digestório (digestão e absorção de lipídios e compostos lipossolúveis), é provavelmente mais sensível ao aumento na suplementação.…”