Low Birth Weight Piglets Research Articles

Short-chain fructo-oligosaccharides supplementation to suckling piglets: Assessment of pre- and post-weaning performance and gut health.

Farmers face difficulties in redeeming their investment in larger litter sizes since this comes with larger litter heterogenicity, lower litter resilience and risk of higher mortality. Dietary oligosaccharides, given to the sow, proved beneficial for the offspring’s performance. However, giving oligosaccharides to the suckling piglet is poorly explored. Therefore, this field trial studied the effect of dietary short-chain fructo-oligosaccharides (scFOS; 1g/day; drenched) supplementation to low (LBW, lower quartile), normal (NBW, two intermediate quartiles) and high (HBW, upper quartile) birth weight piglets from birth until 7 or 21 days of age. Performance parameters, gut microbiome and short-chain fatty acids profile of feces and digesta were assessed at birth (d 0), d 7, weaning (d 21.5) and 2 weeks post-weaning (d 36.5). Additional parameters reflecting gut health (intestinal integrity and morphology, mucosal immune system) were analysed at d 36.5. Most parameters changed with age or differed with the piglet’s birth weight. Drenching with scFOS increased body weight by 1 kg in NBW suckling piglets and reduced the post-weaning mortality rate by a 100%. No clear difference in the IgG level, the microbiota composition and fermentative activity between the treatment groups was observed. Additionnally, intestinal integrity, determined by measuring intestinal permeability and regenerative capacity, was similar between the treatment groups. Also, intestinal architecture (villus lenght, crypt depth) was not affected by scFOS supplementation. The density of intra-epithelial lymphocytes and the expression profiles (real-time qPCR) for immune system-related genes (IL-10, IL-1ß, IL-6, TNFα and IFNγ) were used to assess mucosal immunity. Only IFNγ expression, was upregulated in piglets that received scFOS for 7 days. The improved body weight and the reduced post-weaning mortality seen in piglets supplemented with scFOS support the view that scFOS positively impact piglet’s health and resilience. However, the modes of action for these effects are not yet fully elucidated and its potential to improve other performance parameters needs further investigation.

Low birth weight influences the postnatal abundance and characteristics of satellite cell subpopulations in pigs

Low birth weight (LBW) can cause lifelong impairments in muscle development and growth. Satellite cells (SC) and their progeny are crucial contributors to myogenic processes. This study provides new data on LBW in piglets combining insights on energy metabolism, muscle capillarization and differences in SC presence and function. To this aim, muscle tissues as well as isolated myogenic cells of 4-day-old German Landrace piglets were analyzed. For the first time two heterogeneous SC subpopulations, which contribute differently to muscle development, were isolated from LBW pigs by Percoll density gradient centrifugation. The muscles of LBW piglets showed a reduced DNA, RNA, and protein content as well as lower activity of the muscle specific enzymes CK, ICDH, and LDH compared to their normal birth weight siblings. We assume that deficits in energy metabolism and capillarization are associated with reduced bioavailability of SC, possibly leading to early exhaustion of the SC reserve cell pool and the cells’ premature differentiation.

Impact of sow lactation feed intake on the growth and suckling behavior of low and average birthweight pigs to 10 weeks of age.

Improved genetics in commercial pig production have resulted in larger litter sizes. However this has increased the prevalence of compromised pigs exhibiting inferior birthweights, weaning weights, and lifetime performance. This study aimed to determine the effects of increased sow lactation feed intake on growth of low and average birthweight piglets until 10 wk of age. Low (Low BW; <1 kg) and average (Av BW; 1.3–1.7 kg) birthweight animals were reared in uniformly weighted litters comprising 14 piglets on a foster mother offered either a low (Low FA; max 7.5 kg/d) or high (High FA; max 11 kg/d) feed allowance over a 28- ± 1-d lactation. Piglet performance was monitored from birth until 10 wk of age. Sows offered a High FA consumed 42.4 kg more feed on average than those offered Low FA, resulting in a greater derived milk yield (P < 0.05). Animals of Av BW remained heavier than Low BW pigs throughout the trial (P < 0.05). Piglets reared by High FA sows were heavier at weeks 3, 4, 5, and 7 (P < 0.05) but not week 10 (P > 0.05). Growth rate of piglets relative to their birthweight was significantly greater for Low BW piglets than those of Av BW during lactation (P < 0.001). Piglets reared by sows offered a High FA expressed greater relative growth preweaning (P < 0.05); however, postweaning relative growth for piglets reared on sows offered a Low FA was greater (P < 0.05) suggesting compensatory growth. Neither birthweight nor sow feed allowance significantly affected preweaning mortality (P > 0.05). However, Low BW animals on sows with a High FA recorded half the preweaning mortality of Low BW pigs on sows with a Low FA. During week 1 of lactation, Av BW litters recorded a greater total suckling duration compared to Low BW litters (P < 0.05) but there was no difference in suckling frequency (P > 0.05). During week 3 of lactation, High FA litters displayed a significantly lower suckling frequency (P < 0.05) yet a greater total suckling duration (P < 0.001). Average daily gain was greater for Av BW pigs during weeks 4–7 (P < 0.001) but no difference was recorded between weeks 7 and 10 (P > 0.05). Average daily feed intake was greater for Av BW pigs throughout the nursery period (P < 0.05) but feed–conversion ratio did not differ compared to Low BW pens (P>0.05). In conclusion, offering sows a High FA increased weaning weight of all animals; however, birthweight was the major determinant of postweaning performance.

Outcomes of a low birth weight phenotype on piglet gut microbial composition and intestinal transcriptomic profile

Decades of selection for increased litter size has caused a proportion of sows to consistently produce low birth weight (LBW) litters resulting in economic loss for producers due to reduced piglet survivability and growth. We hypothesized that piglets from LBW litters would have altered gut microbial composition, intestinal architecture, and intestinal transcriptomic profiles compared with piglets from high birth weight (HBW) litters. Sows were designated LBW (n = 45) or HBW (n = 46) based on litter birth weights of three successive parities. LBW piglets were 22% lighter (P &lt; 0.001) at birth; however, no longer differed (P &gt; 0.05) in weight at weaning compared with HBW piglets. LBW piglets had reduced (P &lt; 0.05) fecal microbial diversity with a 114% increase in fecal Enterobacteriaceae (P &lt; 0.05), as well as reduced (P &lt; 0.05) abundance of cecal Roseburia and Faecalibacterium, fiber-degrading butyrate producers. Several genes associated with metabolic (PER2, CES1, KLHL38, and HK2) and immune pathways (IL-1B, IRF8, and TNIP3) were differentially expressed, suggesting altered metabolic and immune function in LBW piglets. In conclusion, LBW piglets had potentially unfavorable shifts in microbial structure in comparison to HBW piglets accompanied with alterations in metabolic and immune gene expression. Results indicate some biological consequences linking LBW phenotype to changes in production efficiency later in life.

Effect of Sows Gestational Methionine/Lysine Ratio on Maternal and Placental Hydrogen Sulfide Production.

Simple SummaryHydrogen sulfide (H2S) is an important second messenger, which has been implicated in regulating placental angiogenesis. Our findings revealed that gestational dietary methionine could affect maternal and placental H2S concentrations. With the increase of dietary methionine, maternal plasma and placental H2S concentrations changed quadratically, which was consistent with placental vascular density and reproductive performance. The decrease in H2S production caused by an increase in dietary methionine was likely to be the cause for the increase in the rate of low birth weight piglets and needs further study.The placenta is a unique bond between the mother and the fetus during pregnancy, and a proper placental angiogenesis is vital for fetal development. H2S is an endogenous stimulator of angiogenesis that is mainly produced by the methionine transsulfurationpathway. The goal of this study was to evaluate the effect of gestational dietary methionine on maternal and placental H2S production in sows. Multiparous sows (Large×White; third parity; n = 65) were randomly allocated into five groups, with feed diets comprisingstandardized ileal digestible methionine/lysine (Met/Lys) ratios of 0.27 (nutrient requirements of swine (NRC); 2012 level), 0.32, 0.37, 0.42, and 0.47, respectively. The litter size and weight at birth were measured and recorded. Maternal blood samples were obtained at embryonic day (E) E40 d, E90 d, and E114 d of gestation. The placental samples were collected at parturition. The results showed that maternal plasma H2S concentration was not affected at E40 d. However, the maternal plasma H2S concentration changed quadratically with the dietary Met/Lys ratio at E90 d (p < 0.01) and E114 d (p = 0.03). The maximum maternal plasma H2S concentration was at the dietary Met/Lys ratio of 0.37. Meanwhile, maternal plasma H2S concentration was positively correlated with piglets born alive (p < 0.01) and litter weight (p < 0.01). Consistent with the maternal plasma, the placental H2S concentration also changed quadratically with the dietary Met/Lys ratio (p = 0.03); the Met/Lys ratio of 0.37 showed the maximum H2S concentration. In conclusion, our findings revealed that the gestational dietary Met/Lys ratio could affect maternal and placental H2S concentrations, which may be an important molecular mechanism affecting placental angiogenesis and piglet development.

Birthweight determines intestinal microvasculature development and alters endothelial nitric oxide synthase density in young piglets.

Blood supply to enterocytes dictates intestinal health and nutrient absorption. These two aspects are impaired in low birthweight (LBW) piglets, but whether the perfusion to intestinal tissues is implicated as well is still unknown. Thus, structural changes in the microvasculature of LBW and normal birthweight (NBW) piglets were investigated during early postnatal development. Additionally, the presence of endothelial nitric oxide synthase (eNOS) in the intestinal mucosa was assessed given its important role to assure perfusion. A total of 22 pigs (11 LBW and 11 NBW) were sacrificed at days 0, 3, 8 and 19 of life. Body weight and intestinal length were recorded and a piece of the small intestine was sampled for immunohistochemical analysis of von Willebrand Factor (vWF, an endothelial cell marker) and eNOS. LBW piglets had a relatively (to body weight) longer intestine than their NBW counterparts. Age did not affect microvasculature, which was more abundant (85% larger vWF-positive area) in NBW than LBW pigs. However, an interaction age*BW was observed for eNOS-IR, showing that eNOS presence peaked in NBW piglets on the first day of life and subsequently decreased. This pattern was not observed in LBW piglets. The less abundant intestinal endothelial mass and the different pattern of eNOS expression observed in LBW piglets suggests microcirculation as a contributing factor in the impaired digestive functioning and gut health of LBW pigs. However, revealing whether the origin of this alteration is prenatal or postnatal, for example due to a lower milk intake, needs further study.

Effects of supplementing late-gestation sow diets with zinc on preweaning mortality of pigs under commercial rearing conditions.

The objective of this experiment was to determine preweaning survival of pigs when sows were supplemented with 3 dietary levels of zinc (Zn) in late gestation. Gilts and sows (n = 339) were assigned to 1 of 3 dietary treatments based on parity. Dietary treatments were 1) Control—sows fed a corn–soybean meal-based diet containing 125 ppm total supplemental Zn supplied by ZnSO4 (75 ppm Zn) and AvailaZn (50 ppm Zn, CON); 2) Intermediate—as Control + 240 ppm supplemental Zn as ZnSO4 (INT); and 3) High—as Control + 470 ppm supplemental Zn as ZnSO4 (HI). Final supplemental Zn concentrations of the 3 dietary treatments were 1) CON—125 ppm; 2) INT—365 ppm; and 3) HI—595 ppm. Sows received dietary treatments from about day 85 of gestation until farrowing. Individual piglet birth weights were recorded within 12 h of parturition. Instances of piglet mortality were recorded daily. The statistical model considered fixed effects of treatment and random effects of parity. Piglets from sows fed the INT diet had heavier (P < 0.05) birth weights than those fed CON (1.42 vs. 1.38 kg, respectively), while offspring from sows fed HI tended to have heavier (P < 0.10) birth weights (1.40 kg) than pigs from INT sows. Furthermore, incidence of low birth weight pigs was less (P < 0.05) for sows consuming INT compared with sows fed CON and HI. Despite differences in birth weight, there were no differences (P > 0.05) in total pigs born, born alive, or weaned, nor differences in individual piglet gain or weaning weight across treatments. Mortality of low birth weight pigs was lowest (P < 0.05) for offspring from sows fed HI (28.1%) compared with offspring from sows fed INT (36.1%) and CON (38.3%). Similarly, overall piglet mortality tended to decrease (P < 0.10) as dietary Zn content increased (CON: 15.0%, INT: 13.2%, and HI: 12.2%). A subset of pigs (n = 420, n = 140/treatment) were selected at weaning to evaluate effects of dietary treatment on postweaning performance. There were no significant effects of sow Zn supplementation on final body weight, days to market, or carcass characteristics of market pigs. Overall, effects of supplemental dietary Zn at 365 and 595 ppm in late gestation improved preweaning survival of low birth weight piglets and reduced overall preweaning mortality of piglets.

Tissue-specific profiling reveals modulation of cellular and mitochondrial oxidative stress in normal- and low-birthweight piglets throughout the peri-weaning period

Weaning is known to induce important nutritional and energetic stress in piglets. Low-birthweight (LBW) piglets, now frequently observed in swine production, are more likely to be affected. The weaning period is also associated with dysfunctional immune responses, uncontrolled inflammation and oxidative stress conditions that are recognized risk factors for infections and diseases. Mounting evidence indicates that mitochondria, the main cellular sources of energy in the form of adenosine 5′ triphosphate (ATP) and primary sites of reactive oxygen species production, are related to immunity, inflammation and bacterial pathogenesis. However, no information is currently available regarding the link between mitochondrial energy production and oxidative stress in weaned piglets. The objective of this study was to characterize markers of cellular and mitochondrial energy metabolism and oxidative status in both normal-birthweight (NBW) and LBW piglets throughout the peri-weaning period. To conduct the study, 30 multiparous sows were inseminated and litters were standardized to 12 piglets. All the piglets were weighted at day 1 and 120 piglets were selected and assigned to 1 of 2 experimental groups: NBW (n = 60, mean weight of 1.73 ± 0.01 kg) and LBW piglets weighing less than 1.2 kg (n = 60, 1.01 ± 0.01 kg). Then, 10 piglets from each group were selected at 14, 21 (weaning), 23, 25, 29 and 35 days of age to collect plasma and organ (liver, intestine and kidney) samples. Analysis revealed that ATP concentrations were lower in liver of piglets after weaning than during lactation (P < 0.05) thus suggesting a significant impact of weaning stress on mitochondrial energy production. Oxidative damage to DNA (8-hydroxy-2′-deoxyguanosine, 8-OHdG) and proteins (carbonyls) measured in plasma increased after weaning and this coincides with a rise in enzymatic antioxidant activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD) (P < 0.05). Mitochondrial activities of both GPx and SOD are also significantly higher (P < 0.05) in kidney of piglets after weaning. Additionally, oxidative damage to macromolecules is more important in LBW piglets as measured concentrations of 8-OHdG and protein carbonyls are significantly higher (P < 0.05) in plasma and liver samples, respectively, than for NBW piglets. These results provide novel information about the nature, intensity and duration of weaning stress by revealing that weaning induces mitochondrial dysfunction and cellular oxidative stress conditions which last for at least 2 weeks and more severely impact smaller piglets.

Neurological functioning and fear responses in low and normal birth weight piglets

Low birth weight (LBW) piglets are an increasingly common occurrence on commercial pig farms, due to selection for sow fecundity. In humans, LBW is a known risk factor for impaired brain development, resulting in impaired neurological functioning and increased vulnerability to stressors. In pigs, the pre-weaning effects of LBW on neurological and emotional functioning are less well known. To assess neurological development, 60 LBW and 60 normal birth weight (NBW) piglets were subjected to a neurological examination at day one after birth. To assess fear responses, another 60 LBW-NBW pairs were compared in a human approach test (HAT) at three weeks of age. In the neurological exam, neonatal LBW piglets were found to be less likely to display a withdrawal reflex in response to a painful stimulus (P = 0.022) and showed impaired coordination during locomotion on a balance beam (P = 0.030). These findings suggest LBW piglets’ increased neonatal mortality, often due to an impaired ability to compete over food or avoid crushing by the sow, could be influenced by a delayed neuromotor development. No effects of birth weight were found on behavioral responses in the HAT, such as latency to approach an unfamiliar human and rate of vocalizations. This suggests LBW and NBW piglets have similar levels of fear in this test. However, we also found indications that the fearfulness displayed by nursing piglets in the HAT is likely due to the temporary removal from the farrowing pen, instead of the presence of an unfamiliar human. Therefore, we can only conclude that LBW does not influence the behavioral response to this combination of stressors (i.e., social isolation from the sow and the piglets’ litter mates, whilst being in a novel environment), as measured by the HAT. Future studies are required to assess whether fear responses to less salient on-farm stressors are affected by birth weight.

56 Observations on pre-weaning piglet mortality

Abstract Pre-weaning piglet mortality (PWM) is a substantial economic loss and a welfare concern. It is not a new issue; however, there is evidence that levels are increasing in US herds. Genetic improvements in prolificacy have been accompanied with lower average piglet birth weights, increased within-litter variation in birth weight, and an increasing proportion of low birth weight piglets. Low birth weight is a major pre-disposing factor for PWM. In a survey involving over 11,000 piglets (average birth weight 1.44 ± 0.390 kg), PWM for piglets weighing 1.5 kg was 44, 15, and 8%, respectively. However, the percentage of total mortality from these 3 weight groupings was 35, 42, and 23%, respectively. This suggests that efforts to reduce PWM should mainly focus on lightest 50% of piglets in a population. The major causes and timing of PWM have not changed over time. Crushing and starvation are predominant; the majority of losses occur in the first few days after birth. A substantial proportion of dead piglets have empty stomachs. Pre-weaning mortality is multifactorial in origin; reducing levels requires attention to all factors, starting with farrowing accommodation design and basic facility hygiene programs. Minimizing piglet body temperature decline after birth, and encouraging early colostrum and milk intake are critical. Strategies to reduce competition between piglets for access to the udder and/or supplementary feeding programs are important. Cross-fostering is central to maximizing piglet survival; however, there is a dearth of research-based information to use to design the optimum strategy. The potential influence of gestation nutrition on PWM requires clarification. Pre-weaning mortality is strongly influenced by the people managing the farrowing facilities; developing approaches for early identification of at risk pigs would have benefit. Ultimately, minimizing PWM requires systems-based approaches involving all components from genetic selection for survival through to facility and animal management practices.

Duodenal Ferroportin Expression Is Unresponsive to Dietary Iron Excess in Nursing Piglets (FS04-01-19)

ObjectivesIn the US, prophylactic iron supplementation without thorough screening for iron deficiency is commonly practiced in both normal weight and low birth weight infants. In a nursing pig model, we previously found that excess dietary iron results in tissue iron overload, suggesting ineffective regulation of intestinal iron absorption. Herein, we aimed to determine if hepcidin-mediated ferroportin (FPN1) degradation is functionally immature in early life. MethodsTwelve nursing piglets of normal birth weight (2.1 ± 0.4 kg, PD2) were supplemented with either low (AGAL, 1 mg/d·kg body weight) or high iron (AGAH, 15 mg/d·kg BW)) in form of ferrous sulfate solution. Eight low birth weight (1.2 ± 0.4 kg on PD2) piglets were supplemented with high iron (SGAH, 15 mg/d·kg BW) from PD2 to 21. All piglets were raised by suckling their sows. Blood samples were collected weekly for analysis of hemoglobin, hematocrit, and plasma iron. Duodenal mucosa (DM) and hepatic mRNA and protein expression of iron transporters and regulators were analyzed using RT-qPCR and Western blot. Data were analyzed using PROC MIXED of SAS with CONTRAST statement for planned comparison between AGAL and high iron groups. ResultsIn comparison with AGAL, high iron, regardless of birth weight, significantly (P < 0.05) increased hemoglobin, transferrin saturation (74% vs. 49%), and plasma iron, and resulted in iron overload in DM and liver at PD21. Hepatic mRNA expression of HAMP and FTL in DM increased 275- and 3-fold, respectively, in response to high iron, whereas DMT1 in DM and TFRC in both liver and DM decreased by 7.4-, 3.8- and 5.3-fold, respectively. Consistently, protein expression of DMT1 in DM was lower in SGAH than that in AGAL; However, both mRNA and protein expression of FPN1 in DM and liver remained unaffected by iron provision or birth weight. ConclusionsHepcidin-induced ferroportin degradation is hypo-responsive to iron excess in a nursing pig model. Funding SourcesUC Davis, NIFA.

A Single Dose of Fat-Based Energy Supplement to Light Birth Weight Pigs Shortly After Birth Does Not Increase Their Survival and Growth.

Simple SummaryIn modern piggeries, due to the increase in litter size (number of piglets born alive), the number of piglets born at a low birth weight (typically under 1.0 kg) is increasing. Those piglets have a lower chance of survival because of their lower body energy reserves, and therefore are of concern for the farmers. Piglets weighing less than 1.1 kg at birth were given an oral dose of fat-based energy (2 mL of coconut oil or 2 mL of a commercial product), 2 mL of water or were only handled but given nothing. This was done to investigate the effects of providing an energy boost at birth on the chances of survival of small piglets. Parameters measured to assess the piglets’ vitality were survival, blood glucose content, rectal temperature, behaviour test of vigour and weight gain. Unfortunately, there was no effect of the energy dose on the parameters measured. Therefore, we conclude that a single dose of energy at birth does not enhance the chances of survival of small piglets. Therefore, using energy product to improve piglet survival at birth may not be the most efficient strategy.Low birth weight piglets are at high risk of mortality, because of the rapid depletion of their energy reserves after birth. At 3 h postpartum, 405 piglets weighing <1.1 kg were either dosed orally with 2 mL of (1) coconut oil (CO, 74 kJ/2 mL, n = 107 piglets), (2) commercial product (CP, 71 kJ/2 mL, n = 101 piglets), (3) water (W, 0 kJ/2 mL, n = 100 piglets) or (4) were sham-dosed (S, n = 97 piglets). Treatments were applied within litter (97 sows). Before treatment piglets were weighed, scored for vitality and blood glucose concentration (subset: CO = 45 piglets, CP = 38 piglets, W = 49 piglets and S = 44 piglets) and rectal temperature were measured. Rectal temperature was remeasured 1 h post-treatment (4 h postpartum). At 24 h post-treatment (27 h postpartum), vitality, weight and blood glucose were remeasured. Piglets were weighed on D5, D7, D10, D14, D21 and at weaning (27 ± 0.1 day old). Mortality rate and cause were recorded until 24h period post-treatment and until weaning. Data were analysed using Generalised Linear Mixed Models in SAS. There was no overall effect of treatment on any of the parameters measured. In conclusion, a single oral of fat-based energy supplement dose at birth did not improve growth, survival, rectal temperature or vitality of low birth weight piglets.

Characterization of the Early Life Microbiota Development and Predominant Lactobacillus Species at Distinct Gut Segments of Low- and Normal-Birth-Weight Piglets.

Microbial exposure during early life plays a pivotal role in modulating the health and intestinal development of the host. Our recent study showed that the low-birth-weight (LBW) piglets harbored a different fecal microbiota compared to normal-birth-weight (NBW) piglets during early life with a lower abundance of the genus Lactobacillus. Considering the spatial variations in gut microbiota at distinct gut locations, this study was designed to further investigate the differences in the microbiota composition and predominant Lactobacillus species in the ileum and colon between LBW and NBW piglets during early life, including day 7 (D7), day 21 (D21, before weaning), and day 35 (D35, 2 weeks after weaning). Compared with the normal group, LBW piglets harbored a significantly lower proportion of short-chain fatty acids producing microbes, such as Ruminococcaceae and Prevotellaceae in the ileum on D7, Alistipes and Lachnospiraceae in the colon on D7, Blautia in the colon on D21, and Ruminiclostridium 9 in the colon on D35. The relative abundance of the phylum Bacteroidetes was also declined in both ileum and colon of LBW piglets on D7. Meanwhile, the levels of total SCFAs on D7, D21, and D35, acetate and valerate on D7 and D21, propionate on D21, and lactate on D21 and D35, were also declined in the colon of LBW piglets. Moreover, functional alterations in the gut microbiota of LBW piglets were characterized by differentially abundant microbial genes involved in multiple pathways such as amino acid metabolism, energy metabolism, replication and repair, and metabolism of cofactors and vitamins in the colon. Additionally, lower numbers of L. salivarius on D7 and L. amylovorus on D21 resided in the colon of LBW piglets compared to those in the normal ones. Collectively, LBW piglets have altered bacterial communities, microbial metabolism and gene functions in the ileum and colon during early life, especially the colonic community. This work will help to develop novel ideas in identifying the reliable biomarkers affecting the gut microbiota development in LBW piglets during early life and facilitate the development of new nutritional interventions.

Exploratory study of the effects of intra-uterine growth retardation and neonatal energy supplementation of low birth-weight piglets on their post-weaning cognitive abilities

The present study investigated the effects of intra-uterine growth retardation (IUGR, score 0–3; i.e., “normal” to “severe”) level at birth, and the effects of neonatal energy supplementation (dosed with 2 ml of coconut oil, commercial product or water, or sham-dosed), on post-weaning cognitive abilities of low birth-weight piglets (< 1.1 kg). In total, 184 piglets were recruited at weaning (27 ± 0.1 days) for habituation to the test procedures, and were either tested for spatial learning and memory in a T-maze (n = 42; 37 ± 0.5 days) or for short-term memory in a spontaneous object recognition task (SORT; n = 47; 41 ± 0.3 days). Neonatal supplementation did not affect performances of pigs in the T-maze task or SORT. IUGR3 pigs tended to be faster to enter the reward arm and to obtain the reward in the reversal step of the T-Maze task, suggesting a better learning flexibility, compared to IUGR1 (entry t72.8=2.9, P = 0.024; reward t80 = 3.28, P = 0.008) and IUGR2 (entry t70.3=2.5, P = 0.068; reward t73.9 = 2.77, P = 0.034) pigs. However, a higher percentage of IUGR1 pigs tended to approach the novel object first (DSCF-value = 3.07; P = 0.076) and to interact with it more (t40 = 2.19, P = 0.085), relative to IGUR3 pigs. IUGR1 pigs showed a strong preference for the novel object, as they had a greater percentage time difference interacting with the objects when the novel object was presented (t81 = − 3.41, P = 0.013). In conclusion, some low birth-weight piglets are able to perform a spatial task and an object recognition test, but performances in these tests may be modulated by IUGR level.

Blood glucose, amino acid profiles and nutrient transporter gene expressions in the small intestine of low and normal birthweight piglets during the early suckling period

Birthweight and age can play a role in adaptational changes in plasma levels of glucose and amino acids by regulating the intestinal expression of specific nutrients transporters in piglets. The aim of the present study was to compare hematological features, circulating levels of glucose and amino acids, and small intestinal gene expression for transporters for glucose (SGLT1, GLUT2), amino acids (LAT2, b0,+AT) and peptides (PepT1) between low birthweight (LBW) and normal birthweight (NBW) piglets at birth prior to suckling and day 7 after birth. A secondary aim was to evaluate correlations between circulating levels of glucose or amino acids and their transporters.There were significant age-dependent changes in the immune cell repertoire in the circulating blood (P<0.004). Blood glucose levels were lower in LBW piglets than in NBW piglets (P<0.05); in both birthweight groups, blood glucose increased with age. Plasma concentrations of histidine, isoleucine, proline and tryptophan showed significant changes with age (P<0.003). With regard to mRNA levels for the nutrient transporters, there were no differences between the two birthweight groups or between the two age groups. At day 7 postpartum, intestinal expression of SGLT1 or GLUT2 mRNA did not correlate with blood glucose level. Expression of LAT2 mRNA in the ileum correlated positively with plasma level of methionine (r=0.92, P<0.001). This is the first detailed analysis of hematological features, plasma glucose and amino acid levels, and nutrient transporter expression in LBW and NBW piglets during the early suckling period.

Effects of parity and litter size on cortisol measures in commercially housed sows and their offspring

Breeding sows are regularly exposed to on-farm stressors throughout the duration of their production period. The impact of such stressors may differ for primi- and multiparous sows, as sows could learn to cope with stressors as they gain experience with them. If parity affects stress in sows, it may also impact their prenatal offspring through differential maternal stress. In addition to parity, litter size is another potential factor involved in stress of sows and piglets. Larger litters may be a source of discomfort for gestating sows, while it can result in intra-uterine growth restriction of piglets. In the current study, we aimed to assess whether parity and litter size affect cortisol measures in breeding sows and their offspring. To do this, we measured salivary cortisol concentrations of 16 primiparous and 16 multiparous sows at three time points: 1) while sows were group housed, 2) after sows were separated from the group prior to moving to the farrowing unit and 3) after handling procedures. In addition, hair cortisol concentration was determined for the sows during late gestation and for their low birth weight (n = 63) and normal birth weight (n = 43) offspring on day 3 after birth, to reflect in-utero cortisol exposure. It was expected that if sows adapt to on-farm stressors, the more experienced, multiparous sows would show decreased stress responses in comparison to primiparous sows. However, we found a comparable acute stress response of primi- and multiparous sows to separation from the group. Handling procedures did not influence sows' salivary cortisol concentrations. Sows' hair cortisol concentration was positively correlated with litter size. Future research is needed to assess whether this finding reflects increased stress in sows carrying larger litters. Parity or litter size did not have a direct effect on their offspring's hair cortisol concentration. Larger litters did have a higher occurrence of low birth weight piglets. For these piglets, females had higher neonatal hair cortisol concentrations than males. Overall, our results indicate that breeding sows do not adapt to all on-farm stressors. In addition, litter size may influence HPA axis activity in both sows and piglets.

PSVI-29 Increased N6-methyladenosine in LBW placentas from sows with high backfat thickness is negatively associated with FTO.

Maternal obesity is associated with low birth weight (LBW), especially in the domestic animals, such as pigs. However, the underlying mechanism how the LBW occurs in the obese pregnancy has not been well clarified.This study was to determine the role of N6-methyladenosine (m6A) modifications in LBW placenta in maternal obesity.1090 multiparous sows were divided into three groups (Low group: backfat thickness ≤17mm, Medium group: backfat thickness 18-20mm, High group: backfat thickness ≥21mm) to analyze the percentage of LBW piglets. 56, 38, and 56 placentas were collected from sows of each group respectively for the further research. Compared with the other two groups, the sows with high backfat thickness increased the percentage of piglets with birth weight ≤0.9kg and ≤1.0kg significantly. In LBW placentas from a high group, the expression of key genes related to placental angiogenesis, PPARγ and VEGFA showed a remarkable decrease, as well as lower vascularity density. Intriguingly, we for the first time reported that m6A modification was significantly increased in LBW placentas from a high group.The expressions of the demethylase, FTO were decreased at mRNA level as well as the protein level. The specific m6A methylations modified in the PPARγ and VEGFA were enhanced in LBW placentas from the high group. We deduce that the m6A modifications modulated by FTO in the key genes may regulate the placental development, resulting in the LBW.

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.

Differences in the Gut Microbiota Establishment and Metabolome Characteristics Between Low- and Normal-Birth-Weight Piglets During Early-Life.

Low-birth-weight (LBW) piglets are at a high-risk for postnatal growth failure, mortality, and metabolic disorders later in life. Early-life microbial exposure is a potentially effective intervention strategy for modulating the health and metabolism of the host. Yet, it has not been well elucidated whether the gut microbiota development in LBW piglets is different from their normal littermates and its possible association with metabolite profiles. In the current study, 16S rRNA gene sequencing and metabolomics was used to investigate differences in the fecal microbiota and metabolites between LBW and normal piglets during early-life, including day 3 (D3), 7 (D7), 14 (D14), 21 (D21, before weaning), and 35 (D35, after birth). Compared to their normal littermates, LBW piglets harbored low proportions of Faecalibacterium on D3, Flavonifractor on D7, Lactobacillus, Streptococcus, and Prevotella on D21, as well as Howardella on D21 and D35. However, the abundance of Campylobacter on D7 and D21, Prevotella on D14 and D35, Oscillibacter and Moryella on D14 and D21, and Bacteroides on D21 was significantly higher in LBW piglets when compared with normal piglets. The results of the metabolomics analysis suggested that LBW significantly affected fecal metabolites involved in fatty acid metabolism (e.g., linoleic acid, α-linolenic acid, and arachidonic acid), amino acid metabolism (e.g., valine, phenylalanine, and glutamic acid), as well as bile acid biosynthesis (e.g., glycocholic acid, 25-hydroxycholesterol, and chenodeoxycholic acid). Spearman correlation analysis revealed a significant negative association between Campylobacter and N1-acetylspermine on D7, Moryella and linoleic acid on D14, Prevotella and chenodeoxycholic acid on D21, and Howardella and phenylalanine on D35, respectively. Collectively, LBW piglets have a different gut bacterial community structure when compared with normal-birth-weight (NBW) piglets during early-life, especially from 7 to 21 days of age. Also, a distinctive metabolic status in LBW piglets might be partly associated with the altered intestinal microbiota. These findings may further elucidate the factors potentially associated with the impaired growth and development of LBW piglets and facilitate the development of nutritional interventions.

Performance of low birth-weight piglets upon protein-energy and/or colostrum supplementation

ABSTRACT The study aimed to investigate the effect of oral protein-energy supplement (OPES) and/or extra colostrum within the first few hours of life on the survival and growth performance of low birth-weight piglets during the suckling period. Based upon nutritional strategy, low-birth-weight piglets (804−1309g) were randomly allocated into four groups: C0S0 (control group, n= 300) - no supplementation; C1S0 (n= 299) - supplementation with 50mL of a colostrum pool through an orogastric tube; C0S1 (n= 298) - oral supplementation with 8mL oral OPES; C1S1 (n= 297) - supplementation with both 50mL of colostrum and 8mL of OPES. The piglets’ body weight was monitored at birth, 24h after birth, on day 7, day 14 and day 20 post-partum. Both colostrum and protein-energy supplementations did not affect (P&gt;0.05) colostrum intake (253.6g; 259.4g; 259.4g; 263.8g for C0S0, C1S0, C0S1, C1S1, respectively), weight gain during the first 24h (62.6g; 68.3g; 67.1g and 69.8g for C0S0, C1S0, C0S1, C1S1, respectively) and pre-weaning mortality (11.3%, 11.4%, 12.4% and 9.4% for C0S0, C1S0, C0S1, C1S1, respectively). Administration of OPES increased (P= 0.032) the average daily weight gain from birth till weaning (189.1 vs. 182.3g) and tended to increase the weight of the piglets (P= 0.060) at weaning (4893.1 vs. 4746.4g for OPES and no OPES, respectively). In conclusion, nutritional manipulation does not affect colostrum intake and pre-weaning mortality of low birth-weight piglets. However, body weight gain during the suckling period and the weight at weaning were observed to be marginally improved by administration of OPES.