Performance and egg quality of laying hens fed different dietary levels of cashew nut shell liquid

Abstract

Organic acids have stood out as alternatives to antibiotic growth promoters, especially those extracted from plants, such as anacardic acid, which is present in cashew nut shell liquid (CNSL). This study evaluates the effects of CNSL as a source of anacardic acid in diets of laying hens on performance, egg quality, lipid stability of yolk and microbiological analysis of excreta. A total of 216 commercial Hisex White laying hens were housed in cages and distributed in a completely randomized design with six treatments and six replicates of six birds per treatment. Treatments consisted of a diet without antibiotic growth promoter (AGP); diet with AGP (Halquinol 60% at 0.1 g/kg and Enramycin 8% at 0.1 g/kg); and four diets without AGP and with the inclusion of 2.5, 5.0, 7.5 and 10.0 g/kg CNSL. No effects of dietary addition of AGP and CNSL were observed in bird performance and external quality of eggs. A quadratic effect was observed for lipid oxidation in egg yolk, the minimum value of which was found at 5.8 g/kg CNSL. There were no significant effects of treatments on total mesophilic, total coliform and thermotolerant coliform counts on excreta. In conclusion, adding up to 10.0 g/kg of CNSL as source of anacardic acid in laying hen diet did not influence performance or egg quality, but the addition from 7.5 g/kg of CNSL upwards reduced lipid oxidation and improved the yolk colour.

Keywords: Anacardium occidentale, lipid oxidation, natural antioxidant, organic acid