To investigate the cumulative effects of maternal supplementation with nucleotides in the form of uridine (UR) on fatty acid and amino acid constituents of neonatal piglets, fifty-two sows in late gestation were assigned randomly into the control (CON) group (fed a basal diet) or UR group (fed a basal diet with 150 g/t UR). Samples of neonates were collected during farrowing. Results showed that supplementing with UR in sows’ diet significantly decreased the birth mortality of pigs (P = 0·05), and increased serum total cholesterol, HDL and LDL of neonatal piglets (P < 0·05). Moreover, the amino acid profile of serum and liver of neonatal piglets was affected by the addition of UR in sows’ diets (P < 0·05). Furthermore, an up-regulation of mRNA expression of energy metabolism-related genes, including fatty acid elongase 5, fatty acid desaturase 1, hormone-sensitive lipase and cholesterol-7a-hydroxylase, was observed in the liver of neonates from the UR group. Additionally, a decrease in placental gene expression of excitatory amino acid transporters 2, excitatory amino acid transporter 3 and neutral AA transporter 1 in the UR group was concurrently observed (P < 0·05), and higher protein expression of phosphorylated protein kinase B, raptor, PPARα and PPARγ in placenta from the UR group was also observed (P < 0·05). Together, these results showed that maternal UR supplementation could regulate placental nutrient transport, largely in response to an alteration of mTORC1–PPAR signalling, thus regulating the nutrition metabolism of neonatal piglets and improving reproductive performance.

Obestatin is a gastrointestinal peptide having wide-ranging effects on cell proliferation; however, its mechanism of action remains poorly understood. Thus, the aim of the study was to elucidate the effect of exogenous obestatin on the postnatal structural development of the small intestine. Seven-day-old piglets with an average BW of 1.56 ± 0.23 kg were divided into four groups (n = 10) that received intragastrically obestatin (2, 10 or 15 μg/kg BW) or vehicle. After a 6-day experimental period, morphological analysis of gastrointestinal tract and small intestine wall (mitosis and apoptosis indexes, histomorphometry of mucosa and muscularis layers) was performed. The study revealed a seemingly incoherent pattern of the histological structure of the small intestine among the experimental groups, suggesting that the effect of obestatin is both intestinal segment specific and dose dependent. Histomorphometric analysis of the small intestine showed that higher doses of obestatin seem to promote the structural development of the duodenum while simultaneously hindering the maturation of more distal parts of the intestine. Intragastric administration of obestatin increased the crypt mitotic index in all segments of the small intestine with the strongest pro-mitotic activity following the administration of obestatin at a dose of 10 and 15 μg/kg BW. The significant differences in the number of apoptotic cells in the intestinal villi among the groups were observed only in proximal jejunum and ileum. In conclusion, it seems that obestatin shows a broad-spectrum of activity in the gastrointestinal tract of newborn piglets, being able to accelerate its structural development. However, the varied effect depending on the intestinal segment or the concentration of exogenous obestatin causes that further research is needed to clarify the exact mechanism of this phenomenon.

Iron-deficiency anemia is a public health concern that frequently occurs in pregnant mammals and neonatal offspring. Ferrous N-carbamylglycinate chelate (Fe-CGly) is a newly designed iron fortifier with proven effects in iron-deficient rats and weanling piglets. However, the effects of this new compound on pregnant mammals are unknown. Therefore, this experiment was conducted to evaluate the effects of Fe-CGly on sow reproductive performance and iron status of both sows and neonatal piglets. A total of 40 large-white sows after second parity were randomly assigned to two groups (n=20). They were receiving a diet including 80 mg Fe/kg as FeSO4 or Fe-CGly, respectively, from day 85 of gestation to parturition. The serum (day 110 of pregnancy) and placentas of sows were sampled. Litter size, mean weight of live born piglets, birth (live) litter weight, number of live born piglets, and the number of still-born piglets, mummies, and weak-born piglets were recorded. Once delivered, eight litters were randomly selected from the 20 litters per treatment, and one new-born male piglet (1.503±0.142 kg) from each selected litter was slaughtered within 3 h after birth from the selected litters, without colostrum ingestion. The serum, longissimus muscle, liver and kidneys of the piglets were collected. The iron status of the serum samples and the messenger RNA level of iron-related genes in the placenta, liver and kidney were analyzed. The results showed that litter weight of live born piglets was higher (P=0.030) in the Fe-CGly group (19.86 kg) than in the FeSO4 group (17.34 kg). Fe-CGly significantly increased placental iron concentration (P<0.05) of sows. It also significantly increased iron saturation and reduced the total iron-binding capacity of piglets (P<0.05) at birth. However, the results revealed that supplementation of Fe-CGly in sows reduced liver and kidney iron concentration of neonatal piglets (P<0.05), indicating decreased iron storage. In addition, the concentration of iron in the colostrum was not significantly changed. Therefore, the present results suggested that replacement of maternal FeSO4 supplement with Fe-CGly in the late-gestating period for sows could improve litter birth weight, probably via enhanced iron transportation in the placenta.