Different Sources of Dietary Zinc for Broilers Subjected to Immunological, Nutritional and Environmental Challenge23 February 2014
Research from Brazil reveals that zinc (from an organic or inorganic source) can be fed to broilers at less than 100ppm without affecting humoral immunity, zinc concentration in the carcass or bird performance. At the same level of zinc, the organic source was more effective in maintaining footpad integrity.
In a paper published in Journal of Applied Poultry Research, M.M. Viera and colleagues at Brazil's Federal University of Rio Grande do Sul in Porto Alegre have reported their investigation into the effects of different sources of dietary zinc for broilers subjected to immunological, nutritional, and environmental challenge
A total of 1,248 one-day-old male Cobb chicks were used to evaluate the effect of different sources and levels of dietary zinc on the humoral immune response, zinc concentration in the tibia and carcass, footpad integrity and performance.
Birds were exposed to the following challenges:
- immunological (infectious bronchitis vaccine in the hatchery)
- nutritional (250ppm of copper in the diet) and
- environmental (reused litter sprayed daily with water between one and 21 days of age).
The diets consisted of different levels of zinc from:
- an organic source (10, 20 or 40ppm of chelate Zn-HMTBa/Mintrex Zn; Novus International Inc.)
- an inorganic source (10, 20, 40 or 100ppm of zinc sulphate), or
- a negative control without zinc (0 ppm of Zn).
The birds were immunised with 0.2mg of BSA at 28 days of age and blood was collected on day 41 to measure antigen-specific antibody titre.
Neither antibody titre, zinc concentration in the carcass nor performance (feed intake, bodyweight gain and feed conversion) were affected by levels or sources of zinc.
The absence of supplementary zinc in the diets significantly decreased its concentration in the tibia ash.
Using 10 or 20ppm of zinc from an organic source decreased the incidence of footpad lesions compared with the same levels of the inorganic source.
Vieira and colleagues concluded that both sources of zinc may be supplemented individually in broiler chicken diets, even in levels below 100ppm, with no effect in carcass zinc concentration, performance or humoral immunity, under the conditions tested.
However, to maintain footpad integrity, they added that an organic source of zinc seemed to be more efficient than the inorganic form.
Vieira M.M., A.M.L. Ribeiro, A.M. Kessler, M.L. Moraes, M.A. Kunrath and V.S. Ledur. 2013. Different sources of dietary zinc for broilers submitted to immunological, nutritional, and environmental challenge. J. Appl. Poult. Res. 22(4):855-861. doi: 10.3382/japr.2013-00753