Food safety assessment of pig clones and their progeny
When it comes to pigs, the FDA could not find any published studies on the meat composition data on clones or clone progeny. The FDA relied solely on data supplied by a cloning company, Viagen, Inc. that had “designed two studies to evaluate the health, growth, and meat composition of swine clones, fertility of boar clones, and health, growth and meat composition of swine clone progeny vs. age-matched, genetically related, artificial insemination (AI)-derived comparator animals” (FDA, 2006: F3). The meat composition data were collected from 4 clones and 242 offspring of clones. Data on 2 more clones were excluded from the study. The data on the excluded clones contradict the finding of no significant differences between cloned and conventional meat.
In the first study, Viagen began with seven clones—6 “Hamline” and 1 “Duroc,” all females—and 15 conventional comparators, all females, that were age-matched and sired by the same Hamline nuclear donor boar in a conventional (e.g. AI) program. These 7 cloned pigs began the study at 50 days of age and all survived until the end of the study at approximately 195 days of age. However, for the comparison of carcass characteristic, Viagen only used data from 4 clones. Two Hamline clones were excluded because they were “approximately 45.45 kg [e.g. 100 pounds] lighter than any of the other animals in the experiment at the time of slaughter” while the Duroc clone was excluded because the carcass was condemned at slaughter due to a lung adhesion (FDA, 2006: F21). In spite of excluding data from 2 clones (about 30% of the total sample size) simply because they were smaller than the other animals, the data clearly showed that the comparators were still over 50% larger than the clones at birth (1.72 kg vs. 1.13 kg, respectively). And excluding data simply because the animals were too small does not seem scientifically valid. The fact that FDA elsewhere admits that these two clones “were euthanized due to chronic health problems at the end of the study” (FDA 2006: F11-F12) is more damning. Excluding clones with chronic health problems from the analysis has the effect of making the SCNT clones resemble normal pigs in the study.
Based on the data from 4 clones, the carcasses of clones tended to have less back fat and to be a slightly darker and more red in color than the non-clone comparators; given the small sample size (4 clones and 15 comparators), only difference with the thickness of back fat measured on the first rib was statistically significant (see Table F-7 in FDA, 2006). FDA suggests that the differences in backfat thickness and marbling color were due to the fact that the clones were also almost 10 pounds lighter, on average, than the non-clone comparators. As noted, two clones that were 100 pounds lighter were removed from the study.
For the meat composition data, FDA only excluded the 2 smallest clones, keeping the data from the Duroc clone that had been condemned at slaughter, so there were data from 5 clones. FDA concluded that the meat composition data “were remarkably similar,