02594naa a2200181 a 450000100080000000500110000800800410001902400540006010000180011424501490013226000090028152019600029065300210225065300170227165300240228870000170231277300830232920354122021-11-09       2017    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1080/10408398.2014.8870562DOI1 aINACIO, C. T.  aPrinciples and limitations of stable isotopes in differentiating organic and conventional foodstuffsb2. Animal products.h[electronic resource]  c2017  aIn this review, we examine the variation in stable isotope signatures of the lighter elements (2H, 13C, d15N, d18O, 34S) of tissues and excreta of domesticated animals, the factors affecting the isotopic composition of animal tissues and whether stable isotopes may be used to differentiate organic and conventional modes of animal husbandry. The main factors affecting the d13C signatures of livestock are the C3 / C4 composition of the diet, the relative digestibility of the diet components, metabolic turnover, tissue and compound specificity, growth rate and animal age. 15N signatures of sheep and cattle products have been related mainly to diet signatures, which are quite variable among farms and between years. Although few data exist, a minor influence in 15N signatures of animal products was attributed to N losses at the farm level, whereas stocking rate showed divergent findings. Correlations between mode of production and 2H and d18O have not been established, and only in one case of an animal product was d34S a satisfactory marker for mode of production. While many data exist on diet-tissue isotopic discrimination values among domesticated animals, there is a paucity of data which allow a direct and statistically-verifiable comparison of the differences in the isotopic signatures of organically- and conventionally-grown animal products. The few comparisons are confined to beef, milk and egg yolk, with no data for swine or lamb products. 13C appears to be the most promising isotopic marker to differentiate organic and conventional production systems when maize (C4) is present in the conventional animal diet. However, 13C may be unsuitable under tropical conditions where C4 grasses are abundant, and where grass-based husbandry is predominant in both conventional and organic systems. At the present time there is no universal analytical method that can be applied to differentiate organic and conventional animal products.  aCriação animal  aDieta animal  aIsótopos estáveis1 aCHALK, P. M.  tCritical Reviews in Food Science and Nutritiongv. 57, n. 1, p. 181-196, 2017.