The determination of effects of in ovo administered monosodium glutamate on the embryonic development of cervical region of medulla spinalis in chicken

In this study, it was aimed to determine the effects of monosodium glutamate (MSG), one of the most widely used flavor enhancing food additives in the world, on the embryonic development of the spinal cord by histological and histometric methods. In this study, 410 fertile chicken eggs were used. Eggs were divided into five groups as control, distilled water, 0.12, 0.6 and 1.2 mg/g egg MSG, and injections were made into the yolk at the beginning of hatching. On the 15th, 18th and 21st days of incubation, medulla spinalis tissue samples were taken from the embryos obtained by opening 10 eggs from each group. After the tissue samples were fixed in 10% formalin, they were blocked in paraffin by routine histological methods. 6 μm thick sections taken from the blocks were stained with the triple staining method of Hematoxylin Eosin, Kluver-Barrera, Toluidine Blue, Periodic Acid Schiff and Crossmon. The preparations were examined under a light microscope and histometric measurements were made in the spinal cord tissue. As a result of histometric measurements made in embryos obtained on the 15th day, when the ratio of the surface area of the substantia grisea to the total surface area of the medulla spinalis observed in the sections, no significant difference was observed between the experimental and control groups in terms of histological organization. On the other hand, after histometric measurements, it was determined that this rate increased in the cervical segments of the embryos in the group treated with MSG at a dose of 1.2 mg/g eggs. In addition, as a result of histometric measurements made in the embryos obtained on the 18th day, it was observed that the ratio of the surface area of the substantia grisea observed in the sections to the total surface area of the medulla spinalis increased in the cervical segments of the embryos in the group treated with MSG at 0.6 mg/g egg dose. On the other hand, it was determined that the embryos in the group treated with MSG at a dose of 0.12 mg/g decreased in the same segments. It was determined that the ratio of the surface area of the substantia grisea to the total surface area of the medulla spinalis observed in the sections was increased especially in the cervical segments of the embryos in the group that received MSG at 0.6 and 1.2 mg/g egg doses. As a result of histometric measurements on the canalis centralis, it was determined that the transverse and longitudinal diameters of the canal were significantly lower in the MSG applied groups compared to the control and distilled water groups. As a result, it was observed that MSG given to fertile chicken eggs just before incubation caused differences in the medulla spinalis tissue compared to the control groups, as a result of light microscopic examinations and histometric measurements.