engleski

Evaluation of fallen autumn leaves as a source of carotenoids for egg yolk pigmentation

Plant leaves are a rich source of carotenoids, which become visible in autumn due to the faster decay of chlorophylls. Carotenoids are a diverse family of yellow-orange pigments contributing to vitamin A, antioxidant and pigment status of animals. However, animals must obtain carotenoids from the diet and plant leaves could be used as a carotenoid source in laying hen diets. Leaves are usually left to decompose naturally, so their potential remains unused. Furthermore, the use of fallen autumn leaves as a dietary supplement for poultry pigmentation has been poorly studied. Therefore, this study was conducted to determine the carotenoid profile in leaves of plant species with intensive autumn leaves colour and to evaluate their potential as a carotenoid source for egg yolk pigmentation. Leaves of five species (Acer saccharinum, Liquidambar styraciflua, Parrotia persica, Quercus robur, and Tilia cordata) were collected (once in October and November 2021). Immediately after collection, leaves were dried at 40 °C, ground, and the content of individual (lutein, zeaxanthin, α- and β-cryptoxanthin, and α- and β-carotene) and total carotenoids (TC ; expressed as β-carotene equivalents) was quantified using HPLC method. Potential daily carotenoid intake in laying hens was calculated based on their contents in leaves and the potential average daily diet intake of the hens (130 g). The addition of 1% or 3% of leaf meal in the diet was assumed based on previous studies. The plant species studied differed in leaf carotenoid profile, with higher contents in Acer saccharinum and Tilia cordata compared to the other species at both sampling dates (250 vs. 112 µg/g DM of TC). Lutein and zeaxanthin, the main carotenoids in the natural hen diet, were the predominant leaf carotenoids in all collected species (79-95% of TC). Content of zeaxanthin was higher than of lutein only in Liquidambar styraciflua leaves. Higher supplementation of plant meals resulted in higher potential carotenoid intake in hens (on average, 931 µg of lutein, 880 µg of zeaxanthin and 2322 µg of TC), which were comparable to diets in previous studies. To achieve higher carotenoid intake, the diet could be supplemented with a higher proportion of leaf meal, but the effects of increasing fiber content on hen performance should be studied to avoid negative impact. In conclusion, meals prepared from fallen autumn leaves of some plant species could be used as a carotenoid source in hen diets after confirming their microbiological and hygienic suitability.

carotenoids ; fallen autumn leaves ; egg yolk ; pigmentation

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