Changes of serum amyloid A, haptoglobin, ceruloplasmin, fibrinogen, and lipid-associated sialic acid in sheep fed high grain rations with altered digestive functions

Changes of serum amyloid A (SAA), haptoglobin (Hp), ceruloplasmin, fibrinogen, and lipid-associated sialic acid (LSA) were assessed in sheep fed high grain rations with negative alterations of digestive functions. During a period of 30 days (divided into three equal steps), eight Karakul lambs were divided into a control (n = 4) and an experiment group (n = 4). The control group was fed a ration consisting of 80% alfalfa hay and 20% wheat straw for the whole period of the study. In the experiment group, ground barley was substituted for 40% of the ration for the first step (10 days) and 62.5% of the ration for the rest of the study (20 days). Negative alterations of digestive functions (decreased rumen pH, reduced feces consistency and dry matter, and reduced feed intake) were evidenced in the experiment group after day 10. On day 0 (beginning of the study) and days 8 and 10 of each step, serum (for SAA, HP, ceruloplasmin, and LSA) and plasma samples (for fibrinogen) were collected from jugular vein. The averages of the eighth and tenth days were used for statistical study. SAA increased in both groups from day 10 afterwards. This increase was significant (P < 0.05) in the experiment group on day 20. Great variations were observed in the concentrations of SAA in individual sheep of the control group. On day 20, the concentration of SAA was significantly higher in the experiment group than that of the control sheep (P < 0.05). HP increased in both groups from day 10 with sharp rises on day 20 (P < 0.05 in the experiment group). Great variations were obvious in the control group on days 20 and 30. Ceruloplasmin, fibrinogen, and LSA were almost constant at various stages of the study with no significant difference between groups. The results reveal that, unlike SAA and HP, levels of ceruloplasmin, fibrinogen, and LSA may not be affected by high grain rations, digestive disorders such as SARA and/or the confounding parameters such as stress. More investigations with larger numbers of animals and focusing on specific markers for stress are suggested for precise differentiations.