This study was conducted in the field of the Poultry Research Station of the Department of Animal Production / Department of Agricultural Research / Ministry of Agriculture for the period 4/4/2021 to 16/5/2021, in which 300 one-day-old Ross308 chicks that fed on diets used avocado oil and Chia with percentages 0, 0.2, 0.4, 0.6% respectively, and their mixture consisting of 0.0, 0.1, 0.2, 0.3 each of avocado and Chia oil (50% avocado + 50% Chia oil). The experiment included 4 treatments with 3 replicates for each treatment (10 birds/replicates), in order to study the effect of using avocado and chia oil and their mixture in meat broiler diets on some physiological and microbial characteristics of blood plasma. The results indicate a significant increase (P < 0.01) in the concentration of total protein and globulin for the treatment birds in which the mixture of avocado and Chia oil was used. While there were no significant differences in the concentration of albumin between the types of the used oils. It was noted through the results that the percentage of usage 0.6% had achieved a high significant increase in the concentration of total protein, albumin and globulin in the blood plasma of the birds of these treatments compared with the rest of the percentages of use (0, 0.2 and 0.4). As for the interaction, the results showed a high significant increase in the protein concentration (P<0.01) in the treatment (M0.6) in both total protein and albumin concentration compared with the rest of the interactions, And the concentration of globulin was significantly increased (P<0.01) in the birds of the treatments (C0.6, M0.2, M0.4, M0.6) compared with the rest of the interactions. The results showed a high significant decrease (P<0.01) in the concentration of cholesterol in the birds of the treatments in which the mixture of oil and Chia oil were used, while a high significant increase (P < 0.01) in the concentration of HDL was observed in the birds that used the mixture of avocado and Chia oil in their diets compared with the other types of oils, While a high significant decrease (P<0.01) in LDL concentration was observed in birds of the treatment with the oil mixture, while no significant differences were observed between types of oils in the concentration of both triglycerides and VLDL. The level of the percentage of usage had a high significant decrease (P < 0.01) in the concentration of cholesterol, triglycerides, LDL and VLDL at all levels of usage 0.2, 0.4 and 0.6% compared to the control treatment, while a high significant (P < 0.01) increase in the concentration of HDL was observed at the rates of use of 0.4 and 0.6% compared with the control treatment which is void of usage. Whereas, the best high significant improvement (P<0.01) in the lipid profile of the lipid plasma was achieved by a mixture treatment with a percentage of use of 0.6% compared with the rest of the interactions. It was noted that there was a high significant increase (P < 0.01) in the number of Lactobacillus bacteria and a high significant decrease (P < 0.01) in the number of E. coli bacteria in the avocado and Chia oil mixture treatments compared with the rest of the used oils. As for the study of the effect of the percentage of use, it increased significantly. (P < 0.01) Lactobacillus bacteria numbers of all usage percentages (0.2, 0.4 and 0.6) compared with the control treatment, in addition to a high significant decrease (P < 0.01) in the numbers of E. coli bacteria. As for the interaction between the type of oil and the percentage of usage, a high significant increase (P < 0.01) was observed in the numbers of Lactobacillus bacteria in the treatment (M0.2 and M0.6) compared with the rest of the interactions, in addition to a high significant decrease (P < 0.01) In the numbers of E.coli bacteria in treatment (M0.6) as the best interaction compared to the rest of the interactions. We conclude from this study that the use of mixed oil at a percentage of 0.4-0.6% in meat broiler diets will improve the physiological characteristics of the blood plasma, in addition to a decrease in the number of harmful bacteria (E. coli) and an increase in the number of beneficial bacteria, which has an important role in improving the physiological condition of birds, which is reflected positively on productive performance and obtaining high growth without the use of harmful synthetic materials.