Immune response, hematological traits, biochemical blood parameters, and histological status of laying hens influenced by dietary chitosan-oligosaccharides

ABSTRACT: This experiment aimed to examine the effect of chitosan-oligosaccharides (COS) supplementation in laying hens' diets affected their immune response, hematological characteristics, blood biochemical parameters, and histological status. At the age of 34 wk, 200 laying hens and 20 cocks of the Mandarah chicken strain were allotted into four groups, each consisting of 50 hens and five cocks. The first group acted as a control group, fed on a basal diet. The second, third, and fourth experimental groups each received 0.1, 0.2, and 0.5 g/kg of COS in addition to a base diet. Birds received COS at various dosages had significantly (P ˂ 0.05) increased serum concentration of immunoglobulins, avian influenza, and Newcastle disease antibodies compared with the control birds. Moreover, adding COS at level 0.2 g/kg diet insignificantly enhanced immune response than the rest of the treatment groups. Also, treated birds with COS at different levels had insignificantly improved hematological parameters such as red blood cells, white blood cells, hemoglobin and hematocrit compared to the control group. Birds fed COS at all levels had significantly decreased serum cholesterol, triglycerides, Ca++ and alanine aminotransferase concentrations compared with control birds. In addition, compared to the control group, chitosan-treated birds showed enhanced histological examination of the small intestine, isthmus, and testis, notably in birds given COS at 0.1 g/kg diet compared to other treated birds. Cocks fed COS at all levels improved testicular tissues and increased the number and diameter of seminiferous tubules compared with control birds Morphological examination of the ileum showed increased villi number, height, and crypt depth. It is possible to conclude that laying hens' physiological performance and general health can be effectively improved by using chitosan at 0.1 or 2 g/kg diet levels enhanced immune response.