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

Effects of maternal feeding of clofibrate on hepatic fatty acid metabolism in suckling piglet

BACKGROUND

Energy deficiency is a leading cause of the high pre-weaning mortality of neonatal piglets in the swine industry. Thus, optimal energy metabolism is of crucial importance for improving the survivability of neonatal piglets. The effective utilization of milk fat as primary energy is indispensably required.

METHODS

Pregnant sows (n = 27) were randomly assigned into 3 treatments. Each treatment received a standard diet (3,265 kcal ME/kg) supplemented with either 0, 0.25% or 0.5% clofibrate (w/w) from d 107 of gestation to d 7 of lactation. The effects of maternal clofibrate on their milk fatty acid (FA) and performance of the piglets were evaluated. The evaluations were performed via measuring sow productive performance, milk FA composition, and hepatic FA oxidation of the piglets at birth and d 1, 7, 14 and 19 after birth.

RESULTS

Maternal supplementation of clofibrate had no effect on reproductive performance of the sows at farrowing and weaning (P > 0.05). However, the mortality at weaning was reduced for piglets from sows with 0.25% of clofibrate, and the average weekly (and daily) gain was higher in piglets from sows that received clofibrate than sows without clofibrate in the first week (P < 0.0001). Maternal clofibrate increased percentage of milk C12:0 and C14:0 FAs but decreased C18:2 and n-6 polyunsaturated FAs. Maternal clofibrate also increased plasma ketone body levels and hepatic FA oxidation measured at the first day of birth, but the increase was not detected in piglets on d 7, 14 or 19. Clofibrate was not detected in milk collected from the clofibrate-treated sows. The percentage of FA oxidation decreased, and the percentage of FA esterification increased with increasing in postnatal age. Supplemental carnitine increased FA oxidation regardless of succinate dehydrogenase inhibition, and the increase had no effect on FA esterification.

CONCLUSIONS

Maternal supplementation of clofibrate during late gestation and early lactation increases hepatic FA oxidative metabolism at birth and improves growth performance of newborn piglets. Maternal clofibrate transfer to suckling piglets via milk was not detected. Carnitine availability is critical for piglets to maintain a high FA oxidation rate during the suckling period.

Efficacy of energy supplementation on growth performance and immune response of suckling pigs

Three studies were performed to determine the effects of oral energy sources on the performance, immune status, and intestinal morphology of piglets. In Exp. 1, 50 litters were selected based on genotype and parity order to determine the optimum amount of supplemental energy for neonatal pigs. They were distributed according to a 5 × 5 Latin square design, in which columns were represented by 5 sows and rows were represented by 5 newborn weight categories. Treatments consisted of 2 oral doses of 0, 2, 4, 8, or 16 mL of rice bran oil (RBO). There was a positive response of RBO on BW with a numerical difference (P = 0.12) and a significant linear effect (P = 0.04) at weaning. In Exp. 2, litters (n = 340) were randomly allotted to a 2 × 2 factorial arrangement of treatments: RBO supplemented either through oral doses (without supplementation or with 2 mL of RBO) or through prestarter feed (without supplementation or with 2% of RBO replacing 2% of soybean oil). Piglets orally receiving RBO showed a numerical increase in BW at weaning (P = 0.101) compared with the control group. Moreover, piglets supplemented by prestarter feed tended to increase feed intake (P = 0.084). In Exp. 3, litters (n = 245) were selected based on genotype and parity order and they were distributed according to a 7 × 7 Latin square design planed in the same way as in Exp. 1. Each neonatal pig within a litter was randomly assigned to 1 of 7 treatments: 1) control (no supplementation), 2) 2 mL of RBO enriched with omega-3 fatty acids, 3) 2.33 mL of pure glycerin, 4) 1.3 mL of soybean oil, 5) 1.4 mL of linseed oil, 6) 1.68 mL of coconut oil, and 7) 2 mL of RBO. Animal performance was analyzed using 2 data sets: all data (average initial BW of 1.479 kg) and low birth weight (LBW) piglet data (≤1.220 kg initial BW with average of 0.985 kg). Body weight or BW gain (BWG) were not different among treatments (P > 0.10) when all data were analyzed. However, LBW piglets fed coconut oil tended to increase BW (P = 0.099) during the first week. In conclusion, the oral use of RBO may increase BW at weaning and the supplementation by prestarter feed may enhance the feed intake of piglets. In addition, coconut oil may increase BW of LBW piglets in the first week of life without affecting mortality, immune response, or gut morphology. The routine practice of oral supplementation of energy for newborn pigs could be an important tool in swine production.