Assesment of Cloned Animal Products

Recent articles (December 2006 and January 2007) in the Washington Post dealt with the U.S. Food and Drug Administration (FDA) assessment that products from cloned animals including meat and milk do not present a risk to food safety. Editorials in the same paper applauded the FDAs reliance on science to come to their conclusions but reminded readers that was not the same as acceptance in the market place.

The FDA made the decision based on its regulatory authorities to perform “a comprehensive risk assessment of the health of animal clones, their progeny, and the food products derived from them”. The approach that FDA used was apparently a cooperative one with the industries that were to be scrutinized for the impact of their products of cloning. The Center for Veterinary Medicine (CVM) of FDA asked that such products be withheld from the food supply. They also asked the National Research Council of the National Academies of Science to characterize “the hazards in animal biotechnology”.

The FDA asserted several principles related to cloned animals that were the underlying basis for their risk assessment: (1) cloning is not a form of genetic engineering; (2) “Animals used for food in the US are inspected without regard to the method by which they are bred”; (3) “The only remaining hazard(s) from cloning are likely to be subtle in nature.”

The presumption by FDA that cloning is not a form of genetic engineering recognizes that it is not an attempt to improve for some purpose the genetic composition of animals. Nonetheless, cloning may be an important part of many current and future approaches to genetic engineering which will be discussed later.

Points 2 and 3 clearly define the scope of the FDA risk assessment and indicate that current food safety procedures and the nature of cloned animals limit science-based concerns about cloning to potential subtle effects of cloning. Based on a voluminous literature review, FDA recognized that the problems most likely associated with cloning would be from the failure of the somatic cells used as nuclear donors in the cloning procedure (SCNT) to completely transform from a pluripotent state to the totipotent state found in germ cells. They acknowledge that the most severe errors in “reprogramming” will result in early death and thus the observed poor efficiency of cloning. This failure to reprogram completely may result in epigenetic variation between clones and the original individual. FDA is concerned that persistent epigenetic differences might result in a “subclinical physiological effect.”

FDA, in their review of the literature and submitted data, found that clones have the same type of health risks as other animals but at a higher frequency. As reported in the literature they recognize that hydroallantois and dystocia are sometimes present in the surrogate dams carrying cloned lambs or calves. They recognized the potential for large offspring syndrome in cows and lambs and some potential for small offspring in pigs. Cattle and sheep neonates were found to need more support for respiration and body temperature control. Reproductive health was found to be normal and they expect the second generation to lose their epigenetic variances. They found that the available literature and submitted data supports the notion that meat and milk from clones was within normal ranges for most compositional analyses. FDA concluded that meat and milk derived from clones is as safe as that “derived from animals produced using contemporary agricultural practices.” They suggest that data on sheep products needs additional data prior to lifting a moratorium on the products from sheep clones.

Source:

Regulation of animal biotechnology: Research needs
Theriogenology, Volume 68, Supplement 1, 1 September 2007, Pages S3-S8
C.E. Rexroad Jr., R.D. Green and R.J. Wall