The effect of monosodium glutamate on brain, liver, kidney, testis, ovary, fertilization and hatching rate in zebrafish (danio rerio)

Abstract

Monosodium glutamate (MSG) is composed of sodium salt and amino acids that is commonly used to enhance food taste. Although it is safe at consumption level, the adverse effect of MSG had been reported. The present research was intended to evaluate the effect of MSG on the brain, liver, kidney, testes, and ovaries of zebrafish (Danio rerio) which were exposed from embryo stage to adult stage, along with the analyzing of the fertilization rate and hatching rate of zebrafish embryos. From the observation of histopathological changing of different organs of zebrafish after exposed to 10, 100, and 1000 ppm MSG for 60 days compared with control group (zebrafish in each group were mating before sacrificed for study the histopathology. In the next day embryos of zebrafish were collected and analyzed for the numbers, survival rate and hatching rate). The results indicated that liver and kidney in MSG exposed group had significantly higher lesion score (p-value <0.05) compared to the control group. Generalized swelling of hepatocytes and blood congestion in the liver as well as the congestion and decreasing number of distal tubule in the kidney from all of the MSG exposed groups had been found. The severity of the lesions from 1000 ppm MSG exposure group was the highest following by the group of 100 and 10 ppm. However, no detectable lesions in the brain tissue, testes, and ovaries of every group were found. Zebrafish from the 1000 ppm MSG exposed group did not spawn after placing in the mating tank, while in 100 ppm MSG group was lower in the number of embryos than 10 ppm MSG and control group. The survival of fertilized embryos was observed every 24 hours for 120 hours. The result of survival rate in 100 ppm MSG group was significantly lower than the control group. All of zebrafish embryos that can be developed until 96 hours post fertilization were hatching completely. In summary, this study revealed that zebrafish exposed to MSG for 60 days showed liver and kidney lesions and reduced the reproductive performance.