Reproduction Fertility and Development - REPROD FERT DEVELOP. 01/2010; 22(1).
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ABSTRACT: Assessment of general risk posed from transgenic (T) animals is important to their future contributions to society. Identification of potentially harmful properties of transgenic livestock is the initial step in a risk assessment. Direct and indirect impacts of potential harmful properties of T livestock need to be evaluated at 3 levels, namely (1) characterization of how the transgene, its product, and the T livestock behave in their immediate environment, that is, in their barn or pen; (2) determination of possible impacts of large-scale release of T livestock, that is, if they were to be integrated into the larger population of food animal livestock; and (3) determination of the more complex environmental and safety consequences of their release into livestock populations. We previously developed and characterized transgenic swine containing a mammary-specific transgene (bovine alpha-lactalbumin, bALAC) that results in increased milk production in sows. We currently are determining whether bALAC is expressed in tissues of T swine other than the lactating mammary gland and whether the transgene DNA (Tg) crosses into non-transgenic control (C) swine under various physiological and physical conditions. The specific aims addressed in the present study were to determine: (1) whether the Tg can be transferred directly from T animals to C animals by physical association or contact and (2) whether the Tg can be transferred directly from an adult T animal to an adult C animal via mating. The T animals utilized in these studies are in at least generation 10 and have stable incorporation of the Tg. Comparable age- and weight-matched animals, T and C, were housed together allowing for general contact that is normal within swine production, for either 180, 220, or 250 d of age after weaning. Swine due to their behavior ingest saliva, regurgitated food, and stool or urinary products, as well as other bodily fluids and cells during normal housing. In a second study, vaginal, cervical, uterine, oviductal, and ovarian tissues from C females on 2, 7, or 90 d after mating to T males and penis, bulbourethral gland, urethra, testis, and epididymis tissues from C males on 2 or 7 days after mating to Tg females were collected. The presence of Tg in tissues from all C animals was tested via PCR. We have analyzed for the presence of the Tg in various tissues [including mammary gland, salivary gland, skin (sebaceous gland), muscle, lung, liver, kidney, brain, ovary, oviduct, uterus, cervix, vagina, penis, bulbourethral gland, urethra, testis, epididymis, and intestine]. Results indicate no presence of the Tg in tissues of C animals (n = 28) after co-habitation for 180, 220, or 250 d (n = 305 samples analyzed) or at 2 (n = 5), 7(n = 14), or 90 (n = 2) d post-mating (n = 60, 174, or 24 samples analyzed, respectively). The present results suggest that there is no horizontal Tg transmission between T and C pigs due to rearing or mating. This work provides a critical step toward providing rigorous scientific data for risk assessment of transgenic livestock.
Reproduction Fertility and Development 01/2009; 21(1):252-253. · 2.58 Impact Factor
Reproduction Fertility and Development - REPROD FERT DEVELOP. 01/2008; 20(1).