Evaluation of compulsory declaration of crude protein in feed mixtures for poultry

The analysed (Kjeldahl) content of crude protein (CP) in seven standardised formulated feed mixtures for poultry, sampled from 11 feed mills through 8 yrs in western Norway, was compared to the nominal guaranteed level. Samples with analysed CP outside the statutory range were designated as faulty. 3.2% of the samples from the grower mixture were faulty. For the other mixtures: hen1, cage, breeder, chicken, broiler and hen2, the figures were 10.9%, 6.5%, 2.8%, 20.6%, 10.1% and 24.0%, respectively. The nominal mean content of CP ranged from 140 g kg−1 in grower to 220 g kg−1 in hen2. The linear correlation between the percentage of faults and the nominal CP level in the mixtures was significant (p<0.05). On average, 97% of the faulty samples were substandard. Only 3% had a higher CP content than declared. The mixtures produced in some regions were almost without faults; in other regions, the faults were more frequent. An apparent decrease in the overall frequency of faults during the period was recorded, though not at a statistical acceptable level of significance (p>0.05).