Although reported requirements for trace elements in piglets are rather low, high dosages of these compounds are used for their known growth promoting effects. Using high concentrations of trace elements implies certain risks. Besides the environmental impact and possible antimicrobial resistance, the stability of other feed ingredients (e.g. fat) might be compromised by the presence of reactive compounds such as free copper (Luo et al., 2005). The rapid release of reactive copper can also induce oxidative stress to the gut (greater malondialdehyde concentrations) and has negative effects on gut morphology (reduced duodenal villus height), as proven by Fry et al., 2012. Alternatively, hydroxy compounds as a new source of trace elements provide a slower release throughout the digestion process. This slow release is ensured by the covalent hydroxy-bonds, which are stable and only slightly soluble. Gradual release of the active trace elements will prevent the previously mentioned negative effects of high reactivity (Fry et al., 2012). To investigate effects of these hydroxy elements on growth and health parameters, the following study in piglets was performed, comparing CuSO4 and Hydroxy-Cu (TBCC: tribasic copper chloride) as a source of copper in piglet diets.
Material and Methods
In this trial, 192 piglets were assigned to 48 pens containing 6 different treatments (8 replicate pens per treatment). Basal starter and grower diets were fed, for 20 and 25 days respectively, differing in source and concentration of copper (Table 1). Initial weight of the piglets was 9 kg. Individual body weights were measured on day 20 and day 55, and feed intake was collected at pen level. Consistency of the feces was scored during the first two weeks using a 1 to 5 scale (from hard to loose feces).