Influence of the Use of Diatomite-Based Mineral Sprinkles on the Content and Immobilization of Cadmium and Zinc from Poultry Litter

Previous studies have indicated that enriching litter composition with natural minerals can not only alter the biochemical activity of specific groups of microorganisms inhabiting the poultry manure, but also affect its functional properties, including the content of mobile forms of cadmium (Cd) and zinc (Zn). A study was therefore conducted to determine the effect of natural sprinkles made from diatomite (DT), enriched with bentonite (BN) or dolomite (DL), on the sorption capacity towards Cd(II) and Zn(II) and on the immobilization of these elements in the litter during the rearing of chicken broilers. The experiment was conducted with four experimental groups, each comprising six coops of 80 Ross 308 chickens (240 chickens per group). The birds were maintained on wood shavings and peat moss litter. Two groups were not administered litter additives, while the other two groups received the DTBN mixture (75/25; wt/wt, 280 g/m² L) prior to being placed in the facility. In addition, a mixture of DTDL (75/25; wt/wt; 100 g/m² L) was applied on the 10th and 26th days of rearing in selected groups, creating four experimental designs: −/−, +/−, −/+, and +/+. Litter samples for testing were collected on days (D) 0, 10, and 35 of the experiment. The results of the sorption of Cd(II) and Zn(II) indicated that both experimental mixtures exhibited a greater ability to bind these elements than pure diatomite. It was found that the use of diatomite-based mineral sprinkles reduced the mobility of Cd and Zn in the litter at the stage of animal rearing. In the litter analyzed after 35 days of rearing (D35), the content of water-extracted forms of cadmium was not determined. In contrast, a 50% reduction in the content of water-extracted forms of zinc was observed in combinations in which mineral sprinkles were applied compared to the control. The use of such additives, in addition to enhancing zoohygienic conditions, can facilitate the reduction of environmental risks subsequent to the soil application of poultry manure as a fertilizer.