Administration of Glucose at Litter Equalization as a Strategy to Increase Energy in Intrauterine Growth Restricted Piglets

Effects of gruel feeding and oral dextrose on the survivability of pigs after weaning

Two experiments were conducted in a 14,400 head nursery using 3,087 (experiment 1) and 988 (experiment 2) pigs to determine the effect of gruel feeding (experiment 1) and supplemental oral dextrose (experiment 2) on nursery pig survivability after weaning. Upon arrival to the nursery, for experiment 1, the smallest 10% of pigs were selected and randomly placed in pens with 61 to 108 pigs per pen. Pens of small pigs were assigned to one of two treatments in a completely randomized design. Treatments consisted of gruel feeding two or four times per day for 14 d postplacement. At each gruel feeding, approximately 1.13 kg of solid feed was added to a round bowl (Rotecna S.A., Agramunt, Spain) located at the front of each pen and water added at a decreasing rate over time. In experiment 2, every other pig removed for welfare considerations (lameness, sick, or unthrifty) from the general population or pens of small pigs received a single 10 mL oral dose of a 50% dextrose solution (Vet One, MWI Animal Health, Boise, ID), as a source of glucose, before being placed in a removal pen. All removed pigs were tagged and weighed, body temperature recorded, and blood glucose concentration measured prior to and 30 min after entering removal pens. Overall, gruel feeding small pigs two or four times per day for 14 d postplacement did not influence (P > 0.10) mortality from weaning to the end of gruel feeding (3.78% vs. 4.25%, respectively). Likewise, dextrose administration did not influence (P > 0.10) pig mortality after removal to approximately 38 d postweaning (21.4% vs. 23.4% respectively), even though blood glucose concentration increased (P < 0.001) 30 min after removal for pigs administered dextrose. An interaction was observed for blood glucose concentration and body temperature (P < 0.001) where pigs with blood glucose concentrations less than 70 mg/dL had increased mortality as body temperature increased. In contrast, pigs with a blood glucose concentration of 70 mg/dL or greater had decreased mortality as body temperature increased. Pigs weighing less than 4.5 kg also had increased mortality (P < 0.001) compared with pigs weighing greater than or equal to 4.5 kg at removal. In summary, gruel feeding four times per day vs. two times per day or providing a dextrose supplement to pigs removed from the general population did not improve the survivability of pigs after weaning. Additionally, pigs removed with decreased body weight or with body temperature or blood glucose concentrations below or above the normal range had decreased survivability.

Identification of tRNA-derived small RNAs and their potential roles in porcine skeletal muscle with intrauterine growth restriction

Intrauterine growth restriction (IUGR) in humans often manifests as poor growth and delayed intellectual development, whereas in domestic animals it results in increased mortality. As a novel epigenetic regulatory molecule, tRNA-derived small RNAs (tsRNAs) have been reported to be involved in many biological processes. In this study, pigs (35d) were used as a model to characterize tsRNAs by sequencing in normal and IUGR porcine skeletal muscle. A total of 586 tsRNAs were identified, of which 103 were specifically expressed in normal-size pigs and 38 were specifically expressed in IUGR pigs. The tsRNAs formed by splicing before the 5' end anti codon of mature tRNA (tRF-5c) accounted for over 90% of tsRNAs, which were significantly enriched in IUGR pigs than in normal-size pigs. Enriched pathways of differentially expressed tsRNAs target genes mainly included metabolic pathways, Rap1 signaling pathway, endocytosis, mTOR signaling pathway, and AMPK signaling pathway. Regulatory network analysis of target genes revealed that IGF1 was one of the most important molecules of regulatory nodes in IUGR and normal porcine skeletal muscle. In addition, IGF1 was found to be one of the target genes of tRF-Glu-TTC-047, which is a highly expressed tsRNA in IUGR pigs. The findings described herein uncover the role of tsRNAs in IUGR porcine skeletal muscle development, thus providing insights into the prevention and treatment of IUGR in mammals.

The Stomach Capacity is Reduced in Intrauterine Growth Restricted Piglets Compared to Normal Piglets

Simple Summary

Large litters have resulted in a higher percentage of piglets suffering from intrauterine growth restriction (IUGR). There is a higher mortality in this subset of piglets and a large number die because they do not receive enough nutrients for energy within the critical first 24 h after birth. One source of nutrients for energy could be supplementation with extra colostrum from previously milked sows. However, there is no knowledge on the stomach capacity of IUGR piglets, and therefore, of how much colostrum could potentially be supplemented. This is important information in order to recommend how much supplementary colostrum IUGR piglets need in order to survive.

Abstract

Selection for increased litter sizes have decreased the average birth weight of piglets and up to 30% of newborn piglets in Danish herds show signs of intrauterine growth restriction (IUGR). It has been reported that around 48% of liveborn piglets dying between birth and weaning have empty stomachs, and that IUGR piglets do not ingest the recommended amount of colostrum to survive. The aim of this study was to investigate how much colostrum could be administrated depending on whether they were IUGR compared to normal piglets. Seventy-two piglets within 24 h of farrowing were classified as either IUGR or normal based on their head morphology. Stomach weight, length and capacity were measured along with bodyweight (BW). The results displayed a decreased BW, empty stomach weight and capacity in IUGR piglets, as well as a decreased relative stomach capacity in IUGR compared with normal piglets. In conclusion, birth weight is not the only factor influencing stomach capacity, and IUGR piglets have a smaller stomach capacity compared with normal piglets. It is estimated that IUGR piglets have the capacity to be given a bolus of 25 mL per kg/BW, whereas a normal piglet have a higher capacity (30 mL per kg/BW).