Effect of Using Different Levels of Crude Protein and Adding some Amino Acids to the Diet on some Blood Biochemical, Histological and Nitrogen Excretion Characteristics of Laying Hens Lohmann Brown

Abstract

Abstract This experiment was conducted at the poultry house of the Department of Animal Production - College of Agriculture - Tikrit University for the period between 13/2/2021 and 8/5/2021 and aimed to use different levels of crude protein and add some amino acids to the diet of laying hens of Lohmann Brown breed The experiment included 240 chickens at the age of (34) weeks and continued for three production periods, each 28 days long. The treatments were fed as follows: T1: the base diet without any addition (control treatment according to the breeding guide). the other five treatments T2, T3, T4, T5 and T6, the base diet reduced the level of crude protein by 0.5, 1, 1.5, 2, and 2.5, respectively, and supported it with amino acids (lysine, methionine, threonine) to be equal to what it is in the control diet. The results were a significant superiority of the control treatment compared to all treatments of the experiment except for the sixth treatment in total protein in the blood serum, as well as the control treatment was significantly superior to all other treatments of the experiment in the concentration of uric acid in the blood serum. The other experiment treatments, and there was no significant difference between the treatments in the depth of the crypts. As for the ratio between the depth of the crypts and the height of the villus, the fourth and fifth treatments increased significantly compared to the control treatment, and there was no significant difference between them and the rest of the experiment treatments, as well as a significant increase in nitrogen proposed for the sixth treatment. Compared with other experimental parameters.