Metabolizable energy values of fats and protein concentrates for poultry: effect of sex and inclusion level of feedstuffs

Abstract

The ME values of tallow, sunflower oil, soyabean, rapeseed and fish meals were determined by chick assay at various levels of dietary inclusion with both sexes. Female chicks metabolized significantly (P < 0.01) more energy from tallow and fish meal than did male chicks. Energy utilized from other feedstuffs tested did not differ between sexes. Less energy was available from tallow as its level of dietary inclusion increased; this could partly be due to altering the ratio of saturated to unsaturated fatty acids in the diet, leading to reduced absorption of palmitic and stearic acids present in tallow. There were significant interactions between sex of chicks and the levels at which tallow and fish meal were included in the diet. A possible interrelationship between the two feedstuffs in relation to the sex differences in absorption of dietary fat is discussed.