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In mammals, several important physiological functions are modified during the perinatal period while profound changes in nutrition also occur. In utero, the fetus receives from its mother a supply of nutrients, corresponding to a high-carbohydrate/low-fat diet. After birth, newborns are fed with milk, which is a high-fat/ low-carbohydrate diet. Oleate (OLE) is the principle fatty acid (FA) in mammalian colostrum, but its role in the energy supply in enterocytes after birth remains unknown. The aim of this study was to investigate the OLE metabolic fate in isolated piglet enterocytes during the first days of life by measuring its lipid incorporation and esterification compared to β-oxidation. Moreover, we studied the carnitine palmitoyltransferase (CPT) system, which allows the mitochondrial entry of long-chain acyl-CoA for β-oxidation. Newborn pigs from Large White pregnant sows (n = 11) were used either at birth (d0; n = 10) or after 2 d of suckling (d2; n = 13). The d0 pigs were taken before the first sucking and used within 30 min after birth and the d2 pigs were left with their mother and allowed to suck ad libitum. After that animals were killed and the whole jejunoileum was used for cell isolation. Cellular triglycerides (TG) and phospholipids (PL) and FA composition were analyzed, and metabolic end-products of [1-14C]OLE were measured in enterocyte incubations.
The TG content was 6.6-fold higher in enterocytes from pigs on d 2 than in those obtained on d 0, whereas the PL content did not differ. The level of OLE in TG and PL increased (P < 0.05) from 15 and 11% of total FA, respectively, in enterocytes from newborn piglets to 30 and 17%, respectively, in those from d2 pigs. The capacity for OLE utilization was 2.8-fold greater in d2 than in d0 pig enterocytes. The oxidation and esterification rates were enhanced in enterocytes from piglets on d 2 compared to those obtained on d 0, by 4- and 2.6-fold, respectively. The predominant OLE fate was the esterification pathway, representing >85% of OLE metabolized in both groups.
This study shows that in the pig, FA from milk are preserved through intestinal transfer and, owing to their low hepatic oxidation, they can be transported to peripheral tissues where they can be used as energy sources and stored in the adipose tissue.
C Cherbuy, P Guesnet, MT Morel, C Kohl, M Thomas, PH Duée and C Prip-Buus. Oleate metabolism in pig enterocytes is characterized by an increased oxidation rate in the presence of a high esterification rate within two days after birth. 2012. The Journal of Nutrition, 142: 221-226.