## 4 Discussion
A higher biohydrogenation process in lambs supplemented on MO and MOVE treatments also explains the results observed for conjugated linoleic acid (CLA) deposition, which was 14.63% higher in the meat of lambs from the Control treatment. The intensity at which fatty acids in the diet are biohydrogenated in the rumen is drastically reflected in the proportion of CLA in meat and milk [45]. In addition, according to [PERSON] et al. [70], the endogenous conversion rate of stearic acid (t11 C18:1) in c9t11 C18:2 is approximately 87% as a result of the action of the enzyme \(\Delta\)9-desaturase. In the present study, neither the desaturation index nor the expression of the SCD1 gene differed among all treatments, which indicates that the amount of CLA found in the meat of lambs under MO and MOVE treatments was highly influenced by the biohydrogenation process. The inclusion of macadamia oil and vitamin E in the supplement of grazing lambs conferred a higher proportion of c9 C16:1 in the meat; however, these results are not supported by the outcomes of the expression of the SCD1 gene and the activity index of the enzyme \(\Delta\)9-desaturase. SCD1 gene expression did not respond to the increase in c9 C16:1 in the meat from lambs under MOVE treatment, which is explained by the fact that a higher expression of a gene does not necessarily correlate to higher protein concentration or enzyme activity, as numerous processes can occur between transcription and translation events [71]. As in the current study, an increased expression of SCD gene expression is associated with a lower concentration of oleic acid in the diet [72]. Besides, [PERSON] et al. [73] observed in cattle that weight gain was negatively correlated with SCD1 gene expression. Thus, a similar ADG of the lambs, independent of the treatment provided, is in agreement with the results found for the expression of SCD1. The recommended atherogenicity index for lamb is below 1.00 to reduce the influence of diet on the incidence of coronary heart disease [41]. The mean value of the atherogenicity index among all treatments in our experiment was 0.56. According to [PERSON] et al. [74], values below 1.00 for this index reflect to a greater amount of antiatherogenic fatty acids in lamb meat. For the thrombogenicity index, the recommended value for lamb is 1.33 [41]. In the present work, lambs from MO and MOVE treatments had an average thrombogenicity of 1.41, while lambs from the Control treatment had a 3.1% reduction from the maximum allowed (1.33). An increase in thrombogenicity index in lambs from MO and MOVE treatments may be justified by an increase in the proportion of fatty acid C18:0 in the meat, which was 12.27% higher when compared to lambs from the Control treatment. In the current study, the mean n6:n3 ratio was 5.13 and was not influenced by the inclusion of macadamia oil or vitamin E in the diet of the lambs. [PERSON] & [PERSON] [50] described that acceptable values for the benefit of human health of the n6:n3 ratio are around 4:1, which is below the observed average. However, for [PERSON] [75], a ratio of up to 10:1 is not harmful to human health. In the current study, a higher ratio of n6:n3 may have been associated with animal genetics. [PERSON] et al. [76] reported that Dorper lambs tend to deposit higher concentrations of saturated fatty acids at a younger age and, consequently, reduce the amount of PUFAs that make up the phospholipids of the membrane. Some studies that evaluated the fatty acid profile in the Longissimus muscle of Dorper \(\times\) Santa Ines crossbred lambs reported a high n6:n3 ratio of 12.64 [77], 9.43 [78] and 7.23 [79], respectively. The results obtained for gene expression in the muscle are in agreement with the increase in the supply of long-chain fatty acids via the inclusion of macadamia oil in the diet of the lambs (Figure 1), where an absence of dietary effect on the expression of transcription factor SREBP-1c can be observed.