Food Safety Assessment Of Genetically Modified Milk With Human Lactoferrin Gene

ObjectiveThis study followed the Guide to Safety Evaluation of Transgenic Plants issued by the Ministry of Agriculture and based on the principle of substantial equivalence and case analysis. A series of in vitro and in vivo tests were launched on in the milk of cows with human Lactoferrin Gene, including test of protein toxicity and allergenicity, nutritional analysis of whole food, animal feeding test, genetic toxicity test. The effect of exogenous expression protein of human lactoferrin gene on the digestive stability, acute toxicity. sub-chronic toxicity, genetic toxicity nutrition of animal body were observed so as to evaluate the edible safety of transgenic milk and provide theoretical foundation for application prospect and commercialization of genetically modified food.Methods1 Acute oral toxicity test in mice on combinant human lactoferrin:GB15193.3-20032 28-day subacute oral toxicity test in mice on combinant human lactoferrin:(HJ/T 154-2004) and so on;3 Simulating gastric/intestinal juice digestive stability test in vitro on combinant human lactoferrin:the Ministry of Agriculture Bulletin No.869;4 Essential nutrients test on genetically modified milk with human lactoferrin gene GB/T 5413-1997 and so on;5 Acute oral toxicity test in mice/rats on genetically modified milk with human lactoferrin gene:GB15193.3-2003;6 90-day feeding test in rats on genetically modified milk with human lactoferrin gene:(HJ/T 154-2004) and so on;7 Sperm abnormality test in mice on genetically modified milk with human lactoferrin gene:GB15193.7-2003;8 Micronucleus test in mouse bone marrow cells on genetically modified milk with human lactoferrin gene:GB15193.5-2003;9 Ames test on genetically modified milk with human lactoferrin gene GB15193.4-2003.Results1 Acute oral toxicity test in mice on combinant human lactoferrin:both male and female LD50>20g/kg·BW, non-toxic level; 2 28-day subacute oral toxicity test in mice on combinant human lactoferrin:high dose group had an increasing trend in urinary protein, no other toxic effects were observed;3 The recombinant human lactoferrin was digested within 0-15s in simulated gastric juice, indicating that the protein is not digestive stabile; there was still protein band in simulated intestinal fluid, indicating that the protein is digestive stabile;4 There were no significant difference between genetically modified milk with human lactoferrin gene and control milk in protein, carbohydrates, fat, fiber, vitamins and minerals;5 Acute oral toxicity test on genetically modified milk with human lactoferrin gene MTD> 20g/kg·BW in all mice/rats and male/female, non-toxic level;6 90-day feeding test in rats on genetically modified milk with human lactoferrin gene:there were no significant difference between genetically modified milk with human lactoferrin gene and control milk in animal body weight, food intake, food efficiency, haematological indicators, serum biochemical indicators, gross anatomy and histopathology inspection;7 Sperm abnormality test in mice on genetically modified milk with human lactoferrin gene:there were no significant difference in teratospermia rate between genetically modified milk with human lactoferrin gene and control milk;8 Micronucleus test in mouse bone marrow cells on genetically modified milk with human lactoferrin gene:there were no significant difference in micronucleus incidence rate;9 Ames test on genetically modified milk with human lactoferrin gene:result is negative, there were no significant difference in back-mutation bacterial count.ConclusionsThe results show that the major nutritious ingredients are not significantly different between milk of cows with transferred human lactoferrin gene and the control milk. The transgenic milk shows no digestive stability in simulated gastric fluid, while stability in simulated intestinal fluid. The adverse effects of milk of cows with transferred human lactoferrin gene on the health of animal subjects were not observed.