Researchers in Taiwan have found that dry grape extract is an antioxidant solution that can be used as an alternate for vitamin E in shrimp starter diets.
Nor-Feed carried out the 8-week trial at the National Taiwan Ocean University to evaluate the effect of a supplementation with Nor-Grape 80 on the growth performances of the Pacific White shrimp at an early stage. Nor-Grape 80 is a dry grape extract registered as a feed additive in the European Union and many jurisdictions around the world, able to provide a powerful antioxidant effect to optimize vitamin E utilization.
Though the complete replacement of vitamin E is not common, the dry grape extract was utilized as an alternative to vitamin E for the purposes of the study. Five diets were formulated for the trial as follows:
- Control Group: 100 ppm vitamin E
- NG1: 0 ppm vitamin E + 50 ppm Nor-Grape
- NG2: 0 ppm vitamin E + 100 ppm Nor-Grape
- NG3: 0 ppm vitamin E + 150 ppm Nor-Grape
- NG4: 0 ppm vitamin E + 200 ppm Nor-Grape
The initial size of the shrimp in the study was 20 mg (post-larvae stage). Researchers recorded weight gain, Feed Conversion Ratio (FCR) and survival rate.
Results demonstrated that the replacement of vitamin E with Nor-Grape 80 led to an improvement of the FCR in all supplemented groups, despite the fact that vitamin E was totally removed. No difference was observed in terms of mortality between groups.