The effect of immunocastration on adipose tissue deposition and composition in pigs

Adipose Tissue Gene Expression of Entire Male, Immunocastrated and Surgically Castrated Pigs

“…Adipose tissue of EM contains smaller adipocytes than adipose tissue of IC and SC, while there seem to be no differences in the number of adipocytes between EM, IC and SC [16]. However, the present research identified a higher expression of the genes involved in adipocyte proliferation and differentiation (i.e., SCARA5-scavenger receptor class A member 5, LGALS3-galectin 3, RBP1-retinol binding protein 1) in EM than IC or SC.…”

“…With the smaller adipocytes observed in EM than IC and SC pigs [16], we observed a downregulation of the PCK1 and SCD genes (both involved in monocarboxylic metabolic process, small molecule biosynthetic process, PPAR signaling and AMPK signaling pathways) in EM compared with both IC and SC. Phosphoenolpyruvate carboxykinase 1 enzyme is involved in glyceroneogenesis and reesterification of free fatty acids in white adipose tissue [43], and the changes in PCK1 expression and activity were previously associated with the fat quantity [44][45][46][47][48].…”

“…The SCD gene is responsible for the biosynthesis of monounsaturated fatty acids (MUFA) from the saturated fatty acids (SFA). Fatty acid composition data of the backfat demonstrated that IC and SC have increased MUFA content compared to EM [16,24]. Since SCD expression is under the hormonal (e.g., leptin, insulin, androgens) or nutritional regulation [50], the respective differences between male sex categories [11,12] corroborate with the upregulated expression of SCD.…”

“…For instance, this includes genes involved in the synthesis of collagen (e.g., COL1A2, COL6A3), which are the major components of the extracellular matrix (ECM) [22]. It has been demonstrated in different tissues that EM, due to the effect of androgens, have more collagen than castrates [23]; in that respect, IC were shown to be in-between EM and SC [16,24]. Similarly, in cattle, downregulation of genes related to collagen synthesis (including COL1A2) in subcutaneous adipose tissue and muscle have been related to castration [25,26].…”

“…Before the second vaccination (V2), IC pigs are metabolically equal to EM [11,12], but after V2, their metabolism progressively turns towards more castrate-like, with a notable increase in feed intake and fat tissue deposition [13,14], which increases almost linearly with the time elapsed from the V2 to slaughter [15]. We recently demonstrated [16] that the increase in quantity of fat depots after immunocastration is associated with a larger adipocyte and lobulus surface area in the backfat, together with notably increased activity of lipogenic enzymes (i.e., fatty acid synthase, glucose 6-phosphate dehydrogenase, malic enzyme and citrate cleavage enzyme) and increased fat saturation as a result of the elevated de novo synthesis of palmitic and stearic acids.…”