Safety Assessment Of Transgenic Bt Rice Used In Growing Pig Diet

Transgenic Bt brown rice, a genetically modified organism, is made use of geneticengineering which transfers Bacillus thuringiensis endotoxin crystal protein gene intothe rice genome to get the resistance characteristics of lepidoptera insects. Theexperiment was conducted to study the effects of transgenic Bt brown rice on the growthperformance, carcass traits, meat quality and immunity in growing pigs. This researchuse growing pigs as an object, and evaluate the use of Bt gene rice to provide a scientificbasis for the transgenic Bt brown rice safety evaluation system.The experiment was conducted to study the effects of transgenic Bt brown rice onthe growth performance, carcass traits, meat quality and immunity in growing pigs.30Large White piglets (35.76±2.52kg) were randomly allocated into2dietary treatmentswith15replicates per treatment. The control group was fed with basic diet+70%non-transgenic Bt brown rice, and the test group was fed with basic diet+70%transgenic Btbrown rice. This experiment lasted for90days.1. Effect of transgenic Bt brown rice as the dietary ingredients on the growthperformance of growing pigsAs growing pig diet raw material respectively, the average daily gain and feedconversion ratio of TG was higher than the CG, especially in the second phase (46d-90d), but there were no significant differences between the two groups (P>0.05).2. Effect of transgenic Bt brown rice as the dietary ingredients on the carcass traits,meat quality of growing pigsThe dressing percentage and loin eye area of TG is higher than that of CG, butthere were no significant differences between the two groups (P>0.05). At the sametime, other carcass parameters did not show distinct difference(P>0.05). In terms of thequality of meat, transgenic Bt brown rice had no significant effects on muscle PH,lightness, redness, yellowness, conductivity or drip loss of growing pigs(P>0.05).3. Effect of transgenic Bt brown rice as the dietary ingredients on the immunity of growing pigsThe results showed that effect of transgenic Bt brown rice on IgA，IgG，IgMand complement content C3and C4in serum was not significantly different with theCG (P＞0.05). Submicrostructure of liver and spleen of growing pigs in treatment grouphad no pathological changes according to tissue slice observation of two organscompared with control group pigs. And there was no significant differences in immuneorgan index between the two groups (P＞0.05).4. The residues and organ damage of exogenous gene and protein from transgenicBt rice in growing pigsThe results show that transgenic Bt brown rice, as growing pig’s diet, has noeffect on the submicroscopic structure of the visceral organs, and no differences werefound between the two groups. Exogenous protein and exogenous genes were notdetected in tissues organs, body fluids and excreta of growing pigs by PCR and ELISA.Conclusion: the experiments which used Bt brown rice as70percent in growingpig’s diet for90days indicated that the transgenic Bt brown rice and the common brownrice had the same nutritional value, using transgenic Bt brown rice had no effect ongrowth performance, carcass performance, meat performance in growing pigs. Andthere were no damage or influence to immune organs and immune function in growingpigs. Therefore, the transgenic Bt brown rice could replace common brown rice asenergy raw materials in growing pigs. Moreover, the exogenous genes and protein couldbe completely digested and absorbed by digestive tract without any residual in the bodyand had no damage to the visceral organs by using Bt brown rice to70percent ingrowing pig’s diet. However, because of the limit of test animal strains and test time,transgenic Bt brown rice impact on other aspects of growing swine also need to bestudyed by further experimental.