Effect of a grower mixture of reduced energetic value on the chemical composition of broiler hearts and livers

摘要

The purpose of the study was to determine whether the use of a grower mixture of reduced energetic value can affect the chemical composition of the heart and liver in broiler chickens. The experiment involved 144 broiler chickens of the Cobb line, bred in the cage system. One-day-old nestlings were divided through random sampling Into two groups: control and experimental, 72 birds in each. Until day 21 the nestlings In both groups were fed the same typical crushed starter mixture containing 20.5% of total protein, whose energetic value was 3065 kcal EM per 1 kg. From day 22 the diets were diversified. The control group was fed a standard granulated grower mixture containing 19.5% of total protein and with an energetic value of 3200 kcal EM per 1 kg (energy to protein ratio of about 164 kcal MEN/1% crude protein), whereas the experimental group was fed a mixture with a 19% share of total protein and 2900 kcal EM per 1 kg (energy to protein ratio of about 153 kcal MEN/1% crude protein). The use of a grower mixture of reduced energetic value did not lead to any significant differentiation in the body weight of the chickens. Neither did It affect the giblets (heart and liver). The energetic value of the grower mixture had a significant influence on decreasing the content of crude ash and total protein In the broilers' hearts.