Effects of Manganese and Iron Organic Sources in Layer Diets on Nutritional Quality of Eggs

Abstract

Organic trace minerals present a higher bioavailability and stability, therefore lower rates of inclusion in feed will be needed to meet the poultry nutritional requirements which will lead to a lower environmental output. The purpose of this study was to determine the effect of total replacement of the inorganic Mn and Fe salts by organic forms of these elements on nutritional quality of eggs and on apparent absorption coefficients. A study was conducted on 192 laying hens, housed in cages (2 birds/cage), divided into 3 groups (C, E 1 , E 2 ). All groups received a similar diet (17.96% CP and 2724.31 kcal/kg ME). Diet E 1 used the same level of Mn and Fe as diet C, but in chelated form (71.9 mg Mn/kg and 60 mg Fe/kg). Compared to C, diet E 2 had the same level of Fe (inorganic source) but the Mn concentration was 200 mg/kg (organic source). Every two weeks egg samples were collected randomly (18 eggs/group). During the study, all droppings were daily collected in order to form average weekly samples/cage, from which Mn, Fe was determined by FAAS. The replacement of the inorganic Mn and Fe salts by chelates of these minerals in layers diets didn’t affect their performances. The analytical results showed an improvement of nutritional quality of eggs in terms of significant (P≤0.05) increasing of Mn concentration in egg yolk for E 2 (1.84±0.28 mg/kg) compare to C (1.46±0.16 mg/kg) and E 1 (1.59±0.30 mg/kg) but without any statistically assured improvement of Fe concentrations. The apparent absorption coefficients of Fe and Mn were higher for E 2 compare to the other two groups (E 1 , C). A possible explanation of these results could be the existent interactions between the trace elements found in animal organism, a high concentration of Mn being able to influence positively the absorption of Fe in organism. The chelate source of trace minerals can be a way of obtaining Mn enrichment eggs but only using amounts of Mn above conventional rate.