The influence of different concentrations of feed additive, based on shell rock and bentonite, on the growth, blood and meat parameters of the African black ostrich (Struthio camelus) in south-east Kazakhstan

Forty-eight 3-month old African ostrich females were divided into four groups: control and 3 experimental comprising 12 animals each. All the animals were fed the adopted diet and the experimental groups additionally received a feed supplement based on shell rock and bentonite, at a rate of 5 g/kg, 10 g/kg and 15 g/kg, respectively, for 9 months. At the beginning and the end of the experiment blood samples were collected for hematological and biochemical analyses. At the end of the experiment, 3 ostriches from each group were slaughtered and the quality of their meat was examined. At 12 months of age the weight of the birds in the experimental groups was significantly higher (P <= 0.05) in comparison to the control group, by 11 kg, 13.3 kg or 16.4 kg, respectively. During the experiment, an increase in the number of red blood cells, leukocytes and hemoglobin was recorded, however all tested hematological parameters remained within the range of physiological values. The biochemical blood parameters in all groups of ostriches did not change significantly at the beginning and the end of experiment. However, the levels of total protein, glucose, Ca and P in the experimental groups showed an upward trend in correlation with the dosage of the tested feed additive. Feed additive contributed to a change in the chemical composition and biological value of the meat. In comparison with the control group, an increase in ash, fat, protein and energy content, the level of mineral elements and vitamins in the meat of the experimental ostriches was noted, in a reliable dependence on the inclusion rate of the feed additive (P <= 0.05). We concluded that the use of feed additive positively affects body mass and hematological blood parameters, as well as the nutritional and biological value of ostrich meat.