Survival and development of embryos of Gallus gallus domesticus treated with inorganic bromide
The range of bromide (Br-) in groundwater sources surveyed in South Africa is 0 - 18.4 mg/L. The research aimed to establish chicken embryo sensitivity to a range of Br- treatments (mg/L) injected into fertilised Ross-308 eggs in three phases: (1) five eggs injected with 10 mg Br-/L; (2) 45 eggs divided into groups and injected with 0, 1 and 5 mg Br-/L; (3) 148 eggs divided into groups injected with 0, 0.01, 0.05, 0.5, and 1 mg Br-/L. Incubation was at standard conditions. Breakout analysis was done at various stages of incubation. The mass of the embryo and of the heart, liver and brain was measured at Day 20. Statistical analysis used Statistical Analyses System® software FREQ procedure to determine the chi-square goodness-of-fit test for percentages of live or dead embryos within and between treatments. The GLM procedure was applied to test for differences in relative organ mass (g) between treatments using F-test. The results showed: (1) 10 mg Br-/L is toxic; (2) Br- is lethal to embryos at concentrations >1 mg/L and toxic at 1 mg/L; and (3) embryo survival was significantly negatively correlated (R2 = -0.92) with increasing Br- concentrations. Concentrations >0.5 mg Br-/L showed greater risk on differential development. Concentrations >0.01 mg Br-/L showed potentially severe effects on developing embryos. The heart showed the greatest relative growth response followed by the brain. The no observed adverse effect level target water quality range (NOAEL-TWQR) in developing chicken embryos was 0 - 0.01 mg/L.
Keywords: Bromine, embryo model, halogens, maximum residue level, toxicity, water quality