Morphological features of the poultry thymus

Abstract

This article reviews the literature on the morphological features of the poultry thymus. Since the preservation of livestock and disease prevention is a constant problem, the issue of poultry care will always remain in the forefront. Efforts to preserve the population and increase their productivity are directly related to strengthening poultry immunity and the state of their immune system. The study of the morphology of immune system organs allows us to objectively assess the effectiveness of methods for the prevention and treatment of various diseases, as well as to identify critical periods of development of the immune system and the body as a whole. When assessing the immune status of poultry, much attention is paid to the state of lymphoid organs, including the thymus. Currently, aspects related to the dynamics of development of immunocompetent organs during the postnatal period of ontogenesis and the time frame of their involution remain unresolved. Understanding the morphological features of the thymus and its changes is a key element in assessing the function of the immune system. It was found that with the growth and development of chicks, the absolute and relative weight of the thymus increases. However, at the onset of reproductive maturity, these values decrease significantly. Involution of the thymus mass occurs, the boundary between cortical and cerebral substances becomes less distinct, and the cellular composition of the thymus changes. The process of age-related involution is accompanied by a decrease in lymphoid tissue and T-lymphocytes. It is worth noting that the total number of circulating T-lymphocytes remains stable, as this population includes long-lived cells that do not require constant renewal. In this context, there is a change in the ratio of cortical and cerebral substances, the growth of connective tissue stroma and adipose tissue. It is noted that stress factors are one of the causes of early thymic involution, and the degree of development and morphological state of the thymus significantly affect the body's resistance to infections. Changes in the structure and morphometry of the chicken thymus can be an important criterion for the morphological diagnosis of immunodeficiencies in poultry.