AMINO ACID APPARENT DIGESTIBILITY ASSESSMENT FROM LAYING HENS DIETS SUPPLEMENTED WITH OIL INDUSTRY BYPRODUCTS

Iulia Varzaru, Tatiana Panaite, Arabela Untea, Gabriela Cornescu, Mariana Ropota, Il. Van

Abstract
    An experiment was conducted on 114 laying hens in order to determine the amino acid apparent digestibility coefficients from diets supplemented with camelina meal, linseed meal and fenugreek seeds. The hens were assigned to 3 groups (C, E1, E2) and housed in metabolic cages (2 hens / cage, 38 hens / group). The control group received a conventional diet for laying hens with the age of 59 weeks. The experimental diets were enriched in PUFA by using 5% linseed meal and 2 % camelina meal (E1); 3% linseed meal, 3 % camelina meal and 1 % fenugreek seed (E2). During the final week of the experiment (for 5 days), the ingesta, the feed leftovers and the droppings were daily recorded with accuracy for each cage, in order to perform the amino acid balance. The digestibility coefficients of the dietary essential amino acids decreased significantly when compared with the control: for lysine 86.85 ± 2.74 % in C, 83.76 ± 3.83 % in E1, 81.34 ± 2.29 % in E2; for methionine 87.30 ± 1.43 % in C, 84.48 ± 2.71 in E1, 80.83 ± 1.51% in E2; for cystine 87.30 ± 1.43 in C, 86.66 ± 2.11 % in E1, 86.13 % for E2. The amino acid analysis of laying hen eggs revealed a significant decrease (P ≤ 0.05) of lysine, methionine and cystine in the albumen from E2, and a significant decrease (P ≤ 0.05) of methionine in the yolk from E2, when compared with the control. This fact is correlated with the amino acid digestibility coefficients. The results highlight the decreasing effects of laying hens diets supplemented with oily byproducts on amino acid digestibility.

Key words: amino acid, digestibility, oily byproducts, laying hens