Transplacental induction of fatty acid oxidation in term fetal pigs by the peroxisome proliferator-activated receptor alpha agonist clofibrate

Intestinal Carnitine Status and Fatty Acid Oxidation in Response to Clofibrate and Medium-Chain Triglyceride Supplementation in Newborn Pigs

To investigate the role of peroxisome proliferator-activated receptor alpha (PPARα) in carnitine status and intestinal fatty acid oxidation in neonates, a total of 72 suckled newborn piglets were assigned into 8 dietary treatments following a 2 (±0.35% clofibrate) × 4 (diets with: succinate+glycerol (Succ), tri-valerate (TC5), tri-hexanoate (TC6), or tri-2-methylpentanoate (TMPA)) factorial design. All pigs received experimental milk diets with isocaloric energy for 5 days. Carnitine statuses were evaluated, and fatty acid oxidation was measured in vitro using [1-¹⁴C]-palmitic acid (1 mM) as a substrate in absence or presence of L659699 (1.6 µM), iodoacetamide (50 µM), and carnitine (1 mM). Clofibrate increased concentrations of free (41%) and/or acyl-carnitine (44% and 15%) in liver and plasma but had no effects in the intestine. The effects on carnitine status were associated with the expression of genes involved in carnitine biosynthesis, absorption, and transportation. TC5 and TMPA stimulated the increased fatty acid oxidation rate induced by clofibrate, while TC6 had no effect on the increased fatty acid oxidation induced by clofibrate (p > 0.05). These results suggest that dietary clofibrate improved carnitine status and increased fatty acid oxidation. Propionyl-CoA, generated from TC5 and TMPA, could stimulate the increased fatty acid oxidation rate induced by clofibrate as anaplerotic carbon sources.

Effects of bamboo leaf extract intervention on the growth performance, antioxidant capacity, and hepatic apoptosis in suckling piglets

This study investigated whether bamboo leaf extract (BLE) could improve the growth performance, antioxidant capacity, and inhibit hepatic apoptosis in suckling piglets. Sixty-four suckling piglets were orally gavaged with vehicle (CON group) or 100, 200, or 300 mg BLE/kg body weight (BL, BM, and BH groups) at 3 days of age for 21 days (n = 8). The results showed that BLE treatment had no effects on the growth performance (P > 0.05). Compared with the CON group, the BM and BH groups decreased (P <0.05) the jejunal and hepatic malondialdehyde (MDA) contents. Supplementation with BLE increased antioxidant enzymes activities and the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and several targeted genes in the jejunum and liver of suckling piglets. The hepatic apoptosis rate was lower (P >0.05) in BLE treatment than in the CON group. Compared with the CON group, the BLE groups showed increased (P <0.05) mRNA levels of B-cell-lymphoma protein 2 (BCL-2), while decreased (P <0.05) BCL-2-associated X (BAX) and cysteine aspartate specific protease-3 (caspase-3) mRNA levels. The results of protein expressions of BCL-2 and caspase-3 were consistent with those of mRNA levels. Altogether, our results indicated that BLE intervention can improve the antioxidant capacity and inhibit hepatic apoptosis in suckling piglets.

Fatty acid ethyl esters in meconium: A biomarker of fetal alcohol exposure and effect

To determine if meconium fatty acid ethyl esters (FAEE) in rat pups is a good biomarker of prenatal exposure and effect to alcohol, three groups of pregnant rats were studied: one control (pair fed) and two treatment groups given 25% alcohol at 2.2 or 5.5 g-1 kg-1 d-1. The pups were delivered on day 20 and, for each dam, were separated into a male and female group. The body, brain, intestines, and placenta of the pups were obtained, weighed, and stored at -20°C. The pups' intestines (as surrogate of meconium) from each group were pooled, and meconium was analyzed by gas chromatography/mass spectroscopy for FAEE. The meconium showed the following FAEE: ethyl palmitate, ethyl stearate, and ethyl linolenate and were only found in the alcohol-treated group and with high specificity but low sensitivity. Mean body weight of the pups was lower in the treatment groups compared to the control groups. Ethyl palmitate concentration correlated negatively to the pups' mean body and brain weights. Therefore, ethyl palmitate, stearate, and linolenate, in meconium of rat pups prenatally exposed to alcohol, are useful biomarkers of prenatal alcohol exposure, with ethyl palmitate a good biomarker of adverse effect on the pups' body and brain weight.

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.

Pharmacologic activation of peroxisome proliferator-activating receptor-α accelerates hepatic fatty acid oxidation in neonatal pigs

Up-regulation of peroxisome proliferator-activating receptor-α (PPARα) and increasing fatty acid oxidation are important for reducing pre-weaning mortality of pigs. We examined the time-dependent regulatory effects of PPARα activation via oral postnatal clofibrate administration (75 mg/(kg-BW·d) for up to 7 days) on mitochondrial and peroxisomal fatty acid oxidation in pigs, a species with limited hepatic fatty acid oxidative capacity due to low ketogenesis. Hepatic oxidation was increased by 44-147% (depending on fatty acid chain-length) and was attained after only 4 days of clofibrate treatment. Acyl-CoA oxidase (ACO) and carnitine palmitoyltransferase I (CPTI) activities accelerated in parallel. The increase in CPTI activity was accompanied by a rapid reduction in the sensitivity of CPTI to malonyl-CoA inhibition. The mRNA abundance of CPTI and ACO, as well as peroxisomal keto-acyl-CoA thiolase (KetoACoA) and mitochondrial malonyl-CoA decarboxylase (MCD), also were augmented greatly. However, the increase in ACO activity and MCD expression were different from CPTI, and significant interactions were observed between postnatal age and clofibrate administration. Furthermore, the expression of acetyl-CoA carboxylase β (ACCβ) decreased with postnatal age and clofibrate had no effect on its expression. Collectively these results demonstrate that the expression of PPARα target genes and the increase in fatty acid oxidation induced by clofibrate are time- and age-dependent in the liver of neonatal pigs. Although the induction patterns of CPTI, MCD, ACO, KetoACoA, and ACCβ are different during the early postnatal period, 4 days of exposure to clofibrate were sufficient to robustly accelerate fatty acid oxidation.

Activation of PPARα by Oral Clofibrate Increases Renal Fatty Acid Oxidation in Developing Pigs

The objective of this study was to evaluate the effects of peroxisome proliferator-activated receptor α (PPARα) activation by clofibrate on both mitochondrial and peroxisomal fatty acid oxidation in the developing kidney. Ten newborn pigs from 5 litters were randomly assigned to two groups and fed either 5 mL of a control vehicle (2% Tween 80) or a vehicle containing clofibrate (75 mg/kg body weight, treatment). The pigs received oral gavage daily for three days. In vitro fatty acid oxidation was then measured in kidneys with and without mitochondria inhibitors (antimycin A and rotenone) using [1-¹⁴C]-labeled oleic acid (C18:1) and erucic acid (C22:1) as substrates. Clofibrate significantly stimulated C18:1 and C22:1 oxidation in mitochondria (p < 0.001) but not in peroxisomes. In addition, the oxidation rate of C18:1 was greater in mitochondria than peroxisomes, while the oxidation of C22:1 was higher in peroxisomes than mitochondria (p < 0.001). Consistent with the increase in fatty acid oxidation, the mRNA abundance and enzyme activity of carnitine palmitoyltransferase I (CPT I) in mitochondria were increased. Although mRNA of mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme A synthase (mHMGCS) was increased, the β-hydroxybutyrate concentration measured in kidneys did not increase in pigs treated with clofibrate. These findings indicate that PPARα activation stimulates renal fatty acid oxidation but not ketogenesis.