Published in Scientific Papers. Series D. Animal Science, Vol. LXVII, Issue 2
Written by Iulia VARZARU, Arabela Elena UNTEA, Tatiana PANAITE, Gabriela Maria CORNESCU, Mihaela SARACILA, Alexandra Gabriela OANCEA, Petru Alexandru VLAICU
This study aimed to evaluate the effectiveness of oak barn as a natural source of tannins included in low protein diets on the performance parameters, excreta composition, and nitrogen balance of laying hens. A total of 168 Lohmann Brown laying hens, 51 weeks of age, were divided into three dietary treatment groups and housed in digestibility cages. Laying hens were fed 17.5% crude protein (CP) in control 1 (C1), 15.5% CP in control 2 (C2), and 15.5% CP supplemented with 0.5 % oak barn in the experimental group (E). Dietary treatments registered a significant increase (p = 0.001) in laying production in the C2 and E groups, and a significant decrease in average egg weight (p = 0.0002) in the E group. The nitrogen balance assessment showed a significant decrease (p = 0.0004) of the nitrogen excreta in groups with reduced dietary protein (C2 and E) compared to control (C1). The cumulative effect of the two studied factors (oak bark and protein level) led to a reduction in nitrogen elimination through droppings of almost 33%, on average.
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