Norel has conducted a study comparing the bioavailability of different zinc sources in poultry, saying that a better understanding of the mineral's bioavailability is required to fine tune its supplementation levels.
It is necessary to use zinc efficiently, according to Norel, since it is both an essential trace mineral and a heavy metal. Zinc level (and bioavailability) varies significantly between feed ingredients, and so does zinc intake. As a consequence, comfortable safety margins are used, leading to dietary zinc levels being higher than recommended in poultry.
In the study, 300 Cobb broilers (50 percent males and 50 percent females) from 1 to 35 days of age were used. The experimental design included five dietary treatments: Basal diet (control); Zn-sulphate at 150 ppm; zinc methionine (Biomet zinc) at 150 ppm; Zn-sulphate at 450 ppm and Biomet zinc at 450 ppm. Starter feeds were fed from 0 to 21 days and grower feeds from 22 to 35 days of age.
Results indicate that from 21 to 35 days of age, birds receiving Biomet zinc at 150 ppm increased the adg 13.2 percent more than the control group, the rest of treatments being in an intermediate situation. Also, birds with Biomet (150 or 450) and Zn-sulphate 450 had a higher pancreas and bones zinc deposition than the control group.
