The including of marigold (Calendula officinalis L.) in the compound feed for the layers of the net utilization of the energy and protein has been studied. Two new indexes of net utilization have been introduced: Clarc of energy distribution (CED) – the relation between consumed metabolizable energy and accumulated gross energy in the egg mélange and Clarc of protein transformation (CPT) – the relation between consumed crude protein and accumulated crude protein in the egg mélange.
The results show that 0.5% of the additive in the hens’ diet influences on the net utilization: CED (fodder – egg mélange) was 0.1891 for the experimental group against 0.1820 for the control group. CPT was 0.2562 against 0.2358 respectively. The differences (especially for CPT) may arouse the interest of the scientific community in collecting more data in this field.
Keywords: Clarc of energy distribution, Clarc of protein transformation, marigold flowers’ addition, layer’s egg mélange