| المستخلص: |
This study was carried out at Poultry Production Farm, Faculty of Agriculture and Veterinary Medicine, Qassim University, to evaluate the immunogenetic profile of Saudi local breed (Baladi) comparing with standard egg production line (Leghorn) and Commercial egg production line (Lohmann), for the purpose of inclusion in some selection programs as a tool of genetic improvement. In this respect growth related body weights, maturation measurements, egg production and egg quality measurements, feed consumption and feed conversion, blood components, blood plasma and blood protein analysis were measured and recorded, Evaluation of immunogenetic aspects was executed using well defined evaluation tests e.g. weights of lymphoid organs, cell mediated immunity assay, antibody response against sheep red blood cells (SRBC's) and specific antibody against Newcastle Disease Virus (NDV). Main results of our study could be summarized as follows: 1- Growth related body weight: Lohmann strain owned significantly (P≤ 0.05) heavier body weight at early period of growing (4, 8, 12 and 16 weeks old) than Baladi chicks. 2- Maturation Age: Earlier maturation was possessed by Lohmann strain while Leghorn and Baladi strains owned late maturation and lighter body weight, consecutively. 3- Egg Production measurements: Lohmann strain chickens produced significantly (P≤ 0.05) higher egg: numbers, mass, weight and longer clutch length compared to Baladi strain. 4- Egg quality: Baladi strain had higher yolk % and stiffer eggshell as compared to Leghorn strain, while Lohmann strain owned significantly (P≤ 0.05) yolk weight, albumen weight, albumen % and shell thickness than Baladi and Lohmann strains.
5- Feed consumption and feed conversion: Lohmann strain consumed more feed and produced more egg mass. However, the efficiency of consumed feed goes to Baladi strain the highest in feed conversion ratio. 6- Blood components: Baladi strain had significantly higher WBC's (P≤ 0.05) and Thrombocytes (related to Immunity system), while Lohmann and Leghorn have higher (P≤ 0.05) values of SRBC's, Hemoglobin and Hematocrit than Baladi strain. 7- Blood Plasma analysis: Baladi strain had more calcium in their bloods (important for eggshell formation), while Lohmann strain had higher cholesterol in their blood. 8- Blood protein analysis: highly significant superiority for Baladi strain regarding total protein, albumen and globulin content in their blood. 9- Immunogenetic profile evaluation: a. Lymphoid organ weights: significant excellence in the side of Lohmann strain regarding spleen, Bursa and Thymus weights followed by Baladi strain ones, while data revealed higher significant superiority for Baladi and Lohmann strain successively regarding thymus %. b. Cell mediated immunity: significant distinction for Baladi strain regarding cell mediated produced after 72 hours of injection with PHA-P. c. Antibody against sheep red blood cells (SRBC's): significant level of antibodies after 21 days of injection with SRBC's has been discovered in the side of Baladi strain. d. Specific antibody against Newcastle disease virus: no significant differences have been detected for antibodies produced against NDV. From all of these results we conclude that Baladi strain owned positive traits and characteristic we could use in selection programs and genetics improvement such as earlier sexual maturity, higher yolk and shell content proportional to egg weight and other contents, higher eggshell solidity, strength and constructive integration, higher calcium level in their blood, higher feed conversion, higher blood contents responsible for immunity resistance against diseases and environmental stresses, higher blood protein, albumin and globulin responsible for improving immunity system, higher % of thymus (lymphoid related organ). Generally, better immunity performance and response against environmental stressors and diseases.
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