Detection of serum protein fractions and their concentrations in laying and non-laying ostriches (Struthio camelus) fed with different dietary protein levels

The aim of this study was to measure serum protein fractions and their concentrations in laying and non-laying ostriches (Struthio camelus) fed with different dietary protein levels. Twenty females, eight years old ostriches were used. The ostriches were randomly divided into two groups to be fed with different protein levels (20% in group I and 23% in group II) during 5 months. There were 2 sections by group according to the laying status. The sections A (in group I) and C (in group II) were constituted by laying ostriches, whereas in the sections B (group I) and D (group II), there were non laying females. At this end of the experimental feeding, serum albumin, alpha(1)- and alpha(2)-, beta- and gamma-globulins were detected by agarose gel electrophoresis and serum total protein, albumin and globulin concentrations were measured by using Auto Technicon DAX 72 autoanalyzer and it's commercial kits. The laying status induced no significant modification of serum protein concentrations (total protein and protein fractions) except for alpha(1)-globuiins whose concentrations were significantly increased (p<0.05). When birds were fed with a high-protein diet, significant increases in protein (p<0.01) and in alpha- (alpha(1)- (p<0.05) and alpha(2)- (p<0.01)) globulin concentrations occurred whereas gamma-globulin concentrations tended to decrease. Moreover, this variation was more evident in non-laying females (interaction between diet and laying status : p<0.05). Since these changes in protein concentrations did not bring a real benefit for the health of the ostriches, and since feeding costs greatly contribute to the total cost of ostrich production, it was concluded that crude protein required in diet did not need to exceed 20% of the food intake.