The suckling piglet as an agrimedical model for the study of pediatric nutrition and metabolism

A 21-day safety evaluation of biotechnologically produced 3-fucosyllactose (3-FL) in neonatal farm piglets to support use in infant formulas

3-Fucosyllactose (3-FL) is one of the most abundant fucosylated oligosaccharides in human breast milk and is an approved infant formula ingredient world-wide. 3-FL functions as a prebiotic to promote early microbial colonization of the gut, increase pathogen resistance and modulate immune responses. To investigate safety and potential gut microbiota effects, 3-FL was fed for 21-days to farm piglets beginning on Postnatal Day (PND) 2. Fructooligosaccharide (FOS), an approved infant formula ingredient, was used as a reference control. Standard toxicological endpoints were evaluated, and the gut microbiota were assessed. Neither 3-FL (245.77 and 489.72 mg/kg/day for males and 246.57 and 494.18 mg/kg/day for females) nor FOS (489.44 and 496.33 mg/kg/day males and females, respectively) produced any adverse differences in growth, food intake or efficiency, clinical observations, or clinical or anatomic pathology changes. Differences in the gut microbiota after 3-FL consumption (versus control and FOS groups) included the absence of Bifidobacterium species from the piglets, enrichment of Prevotellamassilia timonensis, Blautia species, Mediterranea massiliensis, Lachnospiraceae incertae sedis, and Eubacterium coprostanoligens and lower relative abundance of Allisonella histaminiformans and Roseburia inulinivorans. This study further supports the safe use of 3-FL produced using biotechnology as a nutritional ingredient in foods.

Protein turnover in pigs: A review of interacting factors

Protein turnover defines the balance between two continuous and complex processes of protein metabolism, synthesis and degradation, which determine their deposition in tissues. Although the liver and intestine have been studied extensively for their important roles in protein digestion, absorption and metabolism, the study of protein metabolism has focused mainly on skeletal muscle tissue to understand the basis for its growth. Due to the high adaptability of skeletal muscle, its protein turnover is greatly affected by different internal and external factors, contributing to carcass lean-yield and animal growth. Amino acid (AA) labelling and tracking using isotope tracer methodology, together with the study of myofiber type profiling, signal transduction pathways and gene expression, has allowed the analysis of these mechanisms from different perspectives. Positive stimuli such as increased nutrient availability in the diet (e.g., AA), physical activity, the presence of certain hormones (e.g., testosterone) or a more oxidative myofiber profile in certain muscles or pig genotypes promote increased upregulation of translation and transcription-related genes, activation of mTORC1 signalling mechanisms and increased abundance of satellite cells, allowing for more efficient protein synthesis. However, fasting, animal aging, inactivity and stress, inflammation or sepsis produce the opposite effect. Deepening the understanding of modifying factors and their possible interaction may contribute to the design of optimal strategies to better control tissue growth and nutrient use (i.e., protein and AA), and thus advance the precision feeding strategy.

Comparison of maternal and neonatal gut microbial community and function in a porcine model

Our knowledge of the difference in maternal and neonatal gut microbiota composition is not fully understood. Using the Bama miniature pig model, the bacterial community in the feces from sows and piglets was analyzed on an IonS5TMXL platform targeting the single-end reads strategy. Results revealed that the maternal and neonatal bacteria profile in the pig model was distinct. Compared with the piglets, sows had higher proportions of bacteria in Spirochetes, Clostridiales, and Spirochaetales (p < 0.10) and had a lower abundance of bacteria in Tyzzerella (p < 0.05) and Alistipes (p < 0.10). Meanwhile, the proportions of bacteria in Oscillibacter and the index of Chao1, Shannon, and observed_species increased in the sows compared with those in the piglets (p < 0.05). Moreover, the abundance of bacteria associated with the human disease was higher (p < 0.05) and the population of bacteria associated with cellular processes was lower (p < 0.05) in the piglets compared with those in the sows. Collectively, the diversity and beneficial bacteria populations in the sow fecal microbiota exhibit more than those in the piglets. This study indicates that maternal fecal microbiota may be a beneficial source of transplanted bacteria to promote healthy function in neonates.

An Accurate Estimate of the Amino Acid Content of Human Milk Collected from Chinese Women Adjusted for Differences in Amino Acid Digestibility

BACKGROUND

The amino acid (AA) composition of human milk is used to define the AA requirements of the infant. Thus, it is important that estimates of composition be as complete and accurate as possible. When determining AA composition using standard hydrolysis methods, some AAs are progressively destroyed while others are incompletely released. For accuracy, AA composition needs to be determined using multiple hydrolysis times. The true ileal digestibility of AAs also needs to be taken into consideration.

OBJECTIVE

The objective was to bring together AA compositional (determined using multiple hydrolysis intervals) and digestibility data determined using the piglet to give an estimate of the absorbed AA profile of human milk with reference in particular to Asian females.

METHODS

Mature milk was collected from Chinese females. AA analysis using multiple hydrolysis intervals and a nonlinear regression model was used to accurately estimate AA composition. Human milk, as well as a protein-free diet, were fed to piglets (n = 6), and ileal digesta were collected (piglet age, 21 d) to determine the true ileal AA digestibility of AAs in human milk.

RESULTS

True ileal AA digestibility coefficients ranged from (mean ± standard error of the mean) 0.61 ± 0.081 for tyrosine to 1.01 ± 0.030 for tryptophan, with a digestibility for total nitrogen of 0.90 ± 0.013. Convergence criteria were met for the modeling for each AA, and the model had a level of significance of P < 0.0001 for each AA. The amount of available AAs (total AA content as per the model prediction multiplied by the true ileal AA digestibility coefficient determined in the piglet) are reported.

CONCLUSIONS

An estimate of the absorbed AA profile of mature milk collected from Chinese females is provided. For the first time, data is presented for cysteine.

Galacto-Oligosaccharides Alleviate LPS-Induced Immune Imbalance in Small Intestine through Regulating Gut Microbe Composition and Bile Acid Pool

Recent evidence suggests that the protective effect of gut microbiota on intestinal inflammation can be achieved through a microbe-bile acids (BAs) mechanism. Galacto-oligosaccharides (GOS) are a kind of prebiotic that alter gut microbiota composition. To verify whether GOS has a protective effect on intestinal inflammation through a microbe-BAs mechanism, this research was performed in a lipopolysaccharide (LPS) porcine model with the presence or absence of GOS. GOS prevented LPS-induced production of pro-inflammatory cytokines, the decrease of bacterial bile salt hydrolase-containing bacteria abundance, and the decrease of chendoxycholic acid (CDCA) level in piglets. Additionally, CDCA decreased LPS-induced production of pro-inflammatory cytokines, induced the expression of the takeda G-protein receptor 5 (TGR5), and its downstream cyclic adenosine monophosphate (cAMP) production in lamina propria-derived CD11b+ cells. The cAMP inhibitor eliminated the protective effect of CDCA on lamina propria-derived CD11b+ cells. These results suggested that GOS reduced the production of pro-inflammatory cytokines and inhibited NF-κB activation via microbe-BA-dependent TGR5-cAMP signaling in LPS-challenged piglets.

Preterm Pigs Fed Donor Human Milk Have Greater Liver β-Carotene Concentrations than Pigs Fed Infant Formula

BACKGROUND

Milk carotenoids may support preterm infant health and neurodevelopment. Infants fed human milk often have higher blood and tissue carotenoid concentrations than infants fed carotenoid-containing infant formula (IF). Donor human milk (DHM) is a supplement to mother's own milk, used to support preterm infant nutrition.

OBJECTIVES

We tested whether tissue and plasma β-carotene concentrations would be higher in preterm pigs fed pasteurized DHM versus premature IF.

METHODS

This is a secondary analysis of samples collected from a study of the effects of enteral diet composition on necrotizing enterocolitis incidence. Preterm pigs received partial enteral feeding of either DHM (n = 7) or premature IF (n = 7) from 2 to 7 d of age. The diets provided similar β-carotene (32 nM), but DHM had higher lutein, zeaxanthin, and lycopene, whereas IF had higher total vitamin A. Plasma, liver, and jejunum carotenoid and vitamin A concentrations were measured by HPLC-PDA. Jejunal expression of 12 genes associated with carotenoid and lipid metabolism were measured.

RESULTS

Liver β-carotene concentrations were higher in DHM- than IF-fed piglets (23 ± 4 compared with 16 ± 2 μg/g, respectively, P = 0.0024), whereas plasma and jejunal β-carotene concentrations were similar between diets. Liver vitamin A stores were higher in piglets fed IF than DHM (50.6 ± 10.1 compared with 30.9 ± 7.2 μg/g, respectively, P=0.0013); however, plasma vitamin A was similar between groups. Plasma, liver, and jejunum concentrations of lutein, zeaxanthin, and lycopene were higher with DHM than IF feeding. Relative to piglets fed DHM, jejunal low density lipoprotein receptor (Ldlr) expression was higher (61%, P = 0.018) and cluster determinant 36 (Cd36) expression (-27%, P = 0.034) was lower in IF-fed piglets.

CONCLUSIONS

Preterm pigs fed DHM accumulate more liver β-carotene than IF-fed pigs. Future studies should further investigate infant carotenoid bioactivity and bioavailability.

Early Development of Locomotion in the Term Piglet Model: Does Size Matter?

Intrauterine undernutrition in humans typically results in low birth weight ([small for gestational age] SGA) and delayed postnatal neuromotor maturation. Since SGA and intrauterine growth retardation are also common in domestic pigs, piglets are premised as models to study delayed motor development. Applied to the locomotor paradigm, however, questions emerge: (i) how to map the developmental time scale of the precocial model onto the altricial target species and (ii) how to distinguish size from maturation effects? Gait data were collected at self-selected voluntary walking speed during early development (0-96 hours postpartum; pp) for SGA- and normal ([appropriate for gestational age] AGA) piglets. Dimensionless spatiotemporal gait characteristics (according to dynamic similarity) become invariant already after 4 hours pp, suggesting rapid postnatal neuromotor maturation. Moreover, dimensionless gait data are largely identical for SGA- and AGA-siblings, indicating that primarily size effects explain absolute locomotor differences. This is further supported by (i) normalized force-generating capacity of limb muscles, (ii) joint kinematics (<10 hours pp), and (iii) normalized ground reaction forces (<5 days pp) being indifferent between SGA- and AGA- piglets. Furthermore, predictive modeling based on limb joint kinematics is unable to discern the majority of SGA- from AGA-piglets (<10 hours pp). All this leads to the conclusion that, although smaller than the AGA piglets in absolute terms, SGA-piglets mature (neuromechanically speaking) just like, and equally fast as their AGA littermates. Yet, it remains a fact that early SGA piglets are reported to be less mobile, less vital, and less competitive than their AGA siblings (even often die before day 3 pp). This conspicuous difference likely results from the energy level (blood glucose and glycogen) and its mobilization being considerably different between the piglet categories during early development.

Differences in small intestinal apparent amino acid digestibility of raw bovine, caprine, and ovine milk are explained by gastric amino acid retention in piglets as an infant model

Background

The rate of stomach emptying of milk from different ruminant species differs, suggesting that the small intestinal digestibility of nutrients could also differ across these milk types.

Objective

To determine the small intestinal amino acid (AA) digestibility of raw bovine, caprine, and ovine milk in the piglet as an animal model for the infant.

Methods

Seven-day-old piglets (n = 12) consumed either bovine, caprine, or ovine milk diets for 15 days (n = 4 piglets/milk). On day 15, fasted piglets received a single meal of fresh raw milk normalized for protein content and containing the indigestible marker titanium dioxide. Entire gastrointestinal tract contents were collected at 210 min postprandially. Apparent AA digestibility (disappearance) in different regions of the small intestine was determined.

Results

On average, 35% of the dietary AAs were apparently taken up in the small intestine during the first 210 min post-feeding, with 67% of the AA digestibility occurring in the first quarter (p ≤ 0.05) and 33% in the subsequent two quarters. Overall, except for isoleucine, valine, phenylalanine, and tyrosine, the small intestinal apparent digestibility of all AAs at 210 min postprandially in piglets fed ovine milk was, on average, 29% higher (p ≤ 0.05) than for those fed bovine milk. Except for lysine, there was no difference in the apparent digestibility (p > 0.05) of any AAs between piglets fed caprine milk or ovine milk. The apparent digestibility of alanine was higher (p ≤ 0.05) in piglets fed caprine milk than those fed bovine milk. When apparent digestibility was corrected for gastric AA retention, only small differences in the small intestinal apparent digestibility of AAs were observed across milk types.

Conclusion

Bovine, caprine and ovine milk had different apparent small intestinal AA digestibility at 210 min postprandially. When corrected for gastric AA retention, the differences in apparent digestibility across species largely disappeared. The apparent AA digestibility differed across small intestinal locations.

Review on the Impact of Milk Oligosaccharides on the Brain and Neurocognitive Development in Early Life

Milk Oligosaccharides (MOS), a group of complex carbohydrates found in human and bovine milk, have emerged as potential modulators of optimal brain development for early life. This review provides a comprehensive investigation of the impact of milk oligosaccharides on brain and neurocognitive development of early life by synthesizing current literature from preclinical models and human observational studies. The literature search was conducted in the PubMed search engine, and the inclusion eligibility was evaluated by three reviewers. Overall, we identified 26 articles for analysis. While the literature supports the crucial roles of fucosylated and sialylated milk oligosaccharides in learning, memory, executive functioning, and brain structural development, limitations were identified. In preclinical models, the supplementation of only the most abundant MOS might overlook the complexity of naturally occurring MOS compositions. Similarly, accurately quantifying MOS intake in human studies is challenging due to potential confounding effects such as formula feeding. Mechanistically, MOS is thought to impact neurodevelopment through modulation of the microbiota and enhancement of neuronal signaling. However, further advancement in our understanding necessitates clinical randomized-controlled trials to elucidate the specific mechanisms and long-term implications of milk oligosaccharides exposure. Understanding the interplay between milk oligosaccharides and cognition may contribute to early nutrition strategies for optimal cognitive outcomes in children.

Feeding medium-chain fatty acid-rich formula causes liver steatosis and alters hepatic metabolism in neonatal pigs

Medium-chain fatty acids (MCFA) and long-chain fatty acids (LCFAs) are often added to enhance the caloric value of infant formulas. Evidence suggests that MCFAs promote growth and are preferred over LCFAs due to greater digestibility and ease of absorption. Our hypothesis was that MCFA supplementation would enhance neonatal pig growth to a greater extent than LCFAs. Neonatal pigs (n = 4) were fed a low-energy control (CONT) or two isocaloric high-energy formulas containing fat either from LCFAs, or MCFAs for 20 days. Pigs fed the LCFAs had greater body weight compared with CONT- and MCFA-fed pigs (P < 0.05). In addition, pigs fed the LCFAs and MCFAs had more body fat than those in the CONT group. Liver and kidney weights as a percentage of body weight were greater (P ≤ 0.05) for pigs fed the MCFAs than those fed the CONT formula, and in those fed LCFAs, liver and kidney weights as a percentage of body weight were intermediate (P ≤ 0.05). Pigs in the CONT and LCFA groups had less liver fat (12%) compared with those in the MCFA (26%) group (P ≤ 0.05). Isolated hepatocytes from these pigs were incubated in media containing [13C]tracers of alanine, glucose, glutamate, and propionate. Our data suggest alanine contribution to pyruvate is less in hepatocytes from LCFA and MCFA pigs than those in the CONT group (P < 0.05). These data suggest that a formula rich in MCFAs caused steatosis compared with an isocaloric LCFA formula. In addition, MCFA feeding can alter hepatocyte metabolism and increase total body fat without increasing lean deposition.NEW & NOTEWORTHY Our data suggest that feeding high-energy MCFA formula resulted in hepatic steatosis compared with isoenergetic LCFA or low-energy formulas. Steatosis coincided with greater laurate, myristate, and palmitate accumulation, suggesting elongation of dietary laurate. Data also suggest that hepatocytes metabolized alanine and glucose to pyruvate, but neither entered the tricarboxylic acid (TCA) cycle. In addition, the contribution of alanine and glucose was greater for the low-energy formulas compared with the high-energy formulas.

Necroptosis Mediates Muscle Protein Degradation in a Cachexia Model of Weanling Pig with Lipopolysaccharide Challenge

Necroptosis, an actively researched form of programmed cell death closely related to the inflammatory response, is important in a variety of disorders and diseases. However, the relationship between necroptosis and muscle protein degradation in cachexia is rarely reported. This study aimed to elucidate whether necroptosis played a crucial role in muscle protein degradation in a cachexia model of weaned piglets induced by lipopolysaccharide (LPS). In Experiment 1, the piglets were intraperitoneally injected with LPS to construct the cachexia model, and sacrificed at different time points after LPS injection (1, 2, 4, 8, 12, and 24 h). In Experiment 2, necrostatin-1 (Nec-1), a necroptosis blocker, was pretreated in piglets before the injection of LPS to inhibit the occurrence of necroptosis. Blood and longissimus dorsi muscle samples were collected for further analysis. In the piglet model with LPS-induced cachexia, the morphological and ultrastructural damage, and the release of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were dynamically elicited in longissimus dorsi muscle. Further, protein concentration and protein/DNA ratio were dynamically decreased, and protein degradation signaling pathway, containing serine/threonine kinase (Akt), Forkhead box O (FOXO), muscular atrophy F-box (MAFbx), and muscle ring finger protein 1 (MuRF1), was dynamically activated in piglets after LPS challenge. Moreover, mRNA and protein expression of necroptosis signals including receptor-interacting protein kinase (RIP)1, RIP3, and mixed lineage kinase domain-like pseudokinase (MLKL), were time-independently upregulated. Subsequently, when Nec-1 was used to inhibit necroptosis, the morphological damage, the increase in expression of pro-inflammatory cytokines, the reduction in protein content and protein/DNA ratio, and the activation of the protein degradation signaling pathway were alleviated. These results provide the first evidence that necroptosis mediates muscle protein degradation in cachexia by LPS challenge.

Supplemental Clostridium butyricum modulates lipid metabolism by reshaping the gut microbiota composition and bile acid profile in IUGR suckling piglets

BACKGROUND

Intrauterine growth restriction (IUGR) can cause lipid disorders in infants and have long-term adverse effects on their growth and development. Clostridium butyricum (C. butyricum), a kind of emerging probiotics, has been reported to effectively attenuate lipid metabolism dysfunctions. Therefore, the objective of this study was to investigate the effects of C. butyricum supplementation on hepatic lipid disorders in IUGR suckling piglets.

METHODS

Sixteen IUGR and eight normal birth weight (NBW) neonatal male piglets were used in this study. From d 3 to d 24, in addition to drinking milk, the eight NBW piglets (NBW-CON group, n = 8) and eight IUGR piglets (IUGR-CON group, n = 8) were given 10 mL sterile saline once a day, while the remaining IUGR piglets (IUGR-CB group, n = 8) were orally administered C. butyricum at a dose of 2 × 10⁸ colony-forming units (CFU)/kg body weight (suspended in 10 mL sterile saline) at the same frequency.

RESULTS

The IUGR-CON piglets exhibited restricted growth, impaired hepatic morphology, disordered lipid metabolism, increased abundance of opportunistic pathogens and altered ileum and liver bile acid (BA) profiles. However, C. butyricum supplementation reshaped the gut microbiota of the IUGR-CB piglets, characterized by a decreased abundance of opportunistic pathogens in the ileum, including Streptococcus and Enterococcus. The decrease in these bile salt hydrolase (BSH)-producing microbes increased the content of conjugated BAs, which could be transported to the liver and function as signaling molecules to activate liver X receptor α (LXRα) and farnesoid X receptor (FXR). This activation effectively accelerated the synthesis and oxidation of fatty acids and down-regulated the total cholesterol level by decreasing the synthesis and promoting the efflux of cholesterol. As a result, the growth performance and morphological structure of the liver improved in the IUGR piglets.

CONCLUSION

These results indicate that C. butyricum supplementation in IUGR suckling piglets could decrease the abundance of BSH-producing microbes (Streptococcus and Enterococcus). This decrease altered the ileum and liver BA profiles and consequently activated the expression of hepatic LXRα and FXR. The activation of these two signaling molecules could effectively normalize the lipid metabolism and improve the growth performance of IUGR suckling piglets.

Eat like a Pig to Combat Obesity

Obesity and related metabolic health issues are a growing human threat, with many theories regarding its causes. In swine, physiologically alike to humans, considerable knowledge on obesity mechanisms has been accumulated. Calorie counting is the basis for managing swine diets and applied with great accuracy. Epigenetic programing predisposes pigs to insulin insensitivity, but pigs seem to sense this insensitivity and consequently eat less, preventing obesity. Pigs naturally prefer to eat small breakfasts and large dinners. Deviating from this eating pattern or providing diets with a high glycemic burden can trigger obesity; however, pigs will restrict food intake to prevent serious obesity. Interestingly, in practice, problems with obesity are rarely seen, even when pigs are fed poorly timed diets similar to junk food, likely because swine diets are balanced for every nutrient. Indeed, feeding pigs diets deficient in micronutrients does trigger obesity. For humans, several micronutrient requirements have not been set officially, and diets optimized for all micronutrients are rarely provided. In conclusion, various obesity triggers are being debated for humans, which have been proven in swine. Obesity problems in pigs are nevertheless less excessive, likely because pigs recognize unhealthy eating practices and consequently reduce food intake to avoid serious complications. Finally, swine diets are normally balanced for all nutrients, which may be an important practice to prevent obesity, from which human health could greatly benefit.

MicroRNA and mRNA sequencing analyses reveal key hepatic metabolic and signaling pathways responsive to maternal undernutrition in full-term fetal pigs

Maternal undernutrition is highly prevalent in developing countries, leading to severe fetus/infant mortality, intrauterine growth restriction, stunting, and severe wasting. However, the potential impairments of maternal undernutrition to metabolic pathways in offspring are not defined completely. In this study, two groups of pregnant domestic pigs received nutritionally balanced gestation diets with or without 50% feed intake restriction from 0 to 35 gestation days and 70% from 35 to 114 gestation days. Full-term fetuses were collected via C-section on day 113/114 of gestation. MicroRNA and mRNA deep sequencing were analyzed using the Illumina GAIIx system on fetal liver samples. The mRNA-miRNA correlation and associated signaling pathways were analyzed via CLC Genomics Workbench and Ingenuity Pathway Analysis Software. A total of 1189 and 34 differentially expressed mRNA and miRNAs were identified between full-nutrition (F) and restricted-nutrition (R) groups. The correlation analyses showed that metabolic and signaling pathways such as oxidative phosphorylation, death receptor signaling, neuroinflammation signaling pathway, and estrogen receptor signaling pathways were significantly modified, and the gene modifications in these pathways were associated with the miRNA changes induced by the maternal undernutrition. For example, the upregulated (p < 0.05) oxidative phosphorylation pathway in R group was validated using RT-qPCR, and the correlational analysis indicated that miR-221, 103, 107, 184, and 4497 correlate with their target genes NDUFA1, NDUFA11, NDUFB10 and NDUFS7 in this pathway. These results provide the framework for further understanding maternal malnutrition's negative impacts on hepatic metabolic pathways via miRNA-mRNA interactions in full-term fetal pigs.

Role of functional fatty acids in modulation of reproductive potential in livestock

Fatty acids are not only widely known as energy sources, but also play important roles in many metabolic pathways. The significance of fatty acids in modulating the reproductive potential of livestock has received greater recognition in recent years. Functional fatty acids and their metabolites improve follicular development, oocyte maturation and embryo development, as well as endometrial receptivity and placental vascular development, through enhancing energy supply and precursors for the synthesis of their productive hormones, such as steroid hormones and prostaglandins. However, many studies are focused on the impacts of individual functional fatty acids in the reproductive cycle, lacking studies involved in deeper mechanisms and optimal fatty acid requirements for specific physiological stages. Therefore, an overall consideration of the combination and synergy of functional fatty acids and the establishment of optimal fatty acid requirement for specific stages is needed to improve reproductive potential in livestock.

Regulation of skeletal muscle protein synthesis in the preterm pig by intermittent leucine pulses during continuous parenteral feeding

BACKGROUND

Extrauterine growth restriction is a common complication of preterm birth. Leucine (Leu) is an agonist for the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signaling pathway that regulates translation initiation and protein synthesis in skeletal muscle. Previously, we showed that intermittent intravenous pulses of Leu to neonatal pigs born at term receiving continuous enteral nutrition increases muscle protein synthesis and lean mass accretion. Our objective was to determine the impact of intermittent intravenous pulses of Leu on muscle protein anabolism in preterm neonatal pigs administered continuous parenteral nutrition.

METHODS

Following preterm delivery (on day 105 of 115 gestation), pigs were fitted with umbilical artery and jugular vein catheters and provided continuous parenteral nutrition. Four days after birth, pigs were assigned to receive intermittent Leu (1600 µmol kg-1  h-1 ; n = 8) or alanine (1600 µmol kg-1  h-1 ; n = 8) parenteral pulses every 4 h for 28 h. Anabolic signaling and fractional protein synthesis were determined in skeletal muscle.

RESULTS

Leu concentration in the longissimus dorsi and gastrocnemius muscles increased in the leucine (LEU) group compared with the alanine (ALA) group (P < 0.0001). Despite the Leu-induced disruption of the Sestrin2·GATOR2 complex, which inhibits mTORC1 activation, in these muscles (P < 0.01), the abundance of mTOR·RagA and mTOR·RagC was not different. Accordingly, mTORC1-dependent activation of 4EBP1, S6K1, eIF4E·eIF4G, and protein synthesis were not different in any muscle between the LEU and ALA groups.

CONCLUSION

Intermittent pulses of Leu do not enhance muscle protein anabolism in preterm pigs supplied continuous parenteral nutrition.

Low birth weight and reduced postnatal nutrition lead to cardiac dysfunction in piglets

Heart disease is the leading cause of death in humans and evidence suggests early life growth-restriction increases heart disease risk in adulthood. Therefore, this study sought to investigate the effects of low birth weight (LBW) and postnatal restricted nutrition (RN) on cardiac function in neonatal pigs. We hypothesized that LBW and RN would reduce cardiac function in pigs but this effect would be reversed with refeeding. To investigate this hypothesis, pigs born weighing <1.5 kg were assigned LBW, and pigs born >1.5 kg were assigned normal birth weight (NBW). Half the LBW and NBW pigs underwent ~25% total nutrient restriction via intermittent suckling (assigned RN) for the first 4 wk post-farrowing. The other half of piglets were allowed unrestricted suckling access to the sow (assigned NN). At 28 d of age (weaning), pigs were weaned and provided ad libitum access to a standard diet. Echocardiographic, vascular ultrasound, and blood pressure (BP) measurements were performed on day 28 and again on day 56 to assess cardiovascular structure and function. A full factorial three-way ANOVA (NN vs. RN, LBW vs. NBW, male vs. female) was performed. Key findings include reduced diastolic BP (P = 0.0401) and passive ventricular filling (P = 0.0062) in RN pigs at 28 d but this was reversed after refeeding. LBW piglets have reduced cardiac output index (P = 0.0037) and diastolic and systolic wall thickness (P = 0.0293 and P = 0.0472) at 56 d. Therefore, cardiac dysfunction from RN is recovered with adequate refeeding while LBW programs irreversible cardiac dysfunction despite proper refeeding in neonatal pigs.

Weaning Stress in Piglets Alters the Expression of Intestinal Proteins Involved in Fat Absorption

BACKGROUND

In vivo data on intestinal fat absorption in weanling piglets are scarce.

OBJECTIVES

This study aimed to investigate the effect of weaning stress on intestinal fat absorption.

METHODS

Eighteen 7-d-old sow-reared piglets (Duroc-Landrace-Yorkshire) were assigned to 3 groups (n = 6/group, 3 males and 3 females per group). Piglets were nursed by sows until 24 d of age (suckling piglets, S), or weaned at 21 d of age to a corn-soybean meal-based diet until 24 d (3 d postweaning, W3) or 28 d (7 d postweaning, W7) of age, respectively. Duodenum, jejunum, and ileum were collected to determine intestinal morphology and abundance of proteins related to fat absorption.

RESULTS

Compared with the S group, the W3 group had lower villus height (17-34%) and villus height to crypt depth ratio (13-53%), as well as 1-1.45 times greater crypt depth; these values were 1.18-1.31, 0.69-1.15, and 1.47-1.87 times greater in the W7 group than in the W3 group, respectively. Compared with the S group, weaning stress for both W3 and W7 groups reduced intestinal alkaline phosphatase activity (26-73%), serum lipids (26-54%), and abundances of proteins related to fatty acid transport [fatty acid transport protein 4 (FATP4) and intestinal fatty acid-binding protein (I-FABP)] and chylomicron assembly [microsomal triglyceride transfer protein (MTTP), apolipoprotein A-IV (APOA4), B (APOB), and A-I (APOA1)] in the duodenum and ileum (10-55%), as well as in the jejunum (25-85%). All these indexes did not differ between W3 and W7 groups. Compared with the S group, the W3 group had lower mRNA abundances of duodenal APOA4 and APOA1 (25-50%), as well as jejunal FATP4, IFABP, MTTP, APOA4, and APOA1 (35-50%); these values were 5-15% and 10-37% lower in the W7 group than in the W3 group, respectively.

CONCLUSIONS

Weaning stress in piglets attenuates the expression of intestinal proteins related to fatty acid transport (FATP4 and I-FABP) and chylomicron synthesis (APOA4).

Malnourishment affects gene expression along the length of the small intestine

Malnourishment is a risk factor for childhood mortality, jeopardizing the health of children by aggravating pneumonia/acute respiratory infections and diarrheal diseases. Malnourishment causes morphophysiological changes resulting in stunting and wasting that have long-lasting consequences such as cognitive deficit and metabolic dysfunction. Using a pig model of malnutrition, the interplay between the phenotypic data displayed by the malnourished animals, the gene expression pattern along the intestinal tract, microbiota composition of the intestinal contents, and hepatic metabolite concentrations from the same animals were correlated using a multi-omics approach. Samples from the duodenum, jejunum, and ileum of malnourished (protein and calorie-restricted diet) and full-fed (no dietary restrictions) piglets were subjected to RNA-seq. Gene co-expression analysis and phenotypic correlations were made with WGCNA, while the integration of transcriptome with microbiota composition and the hepatic metabolite profile was done using mixOmics. Malnourishment caused changes in tissue gene expression that influenced energetic balance, cell proliferation, nutrient absorption, and response to stress. Repression of antioxidant genes, including glutathione peroxidase, in coordination with induction of metal ion transporters corresponded to the hepatic metabolite changes. These data indicate oxidative stress in the intestine of malnourished animals. Furthermore, several of the phenotypes displayed by these animals could be explained by changes in gene expression.

Comparison of Changes in Gut Microbiota in Wild Boars and Domestic Pigs Using 16S rRNA Gene and Metagenomics Sequencing Technologies

Simple Summary

The microbiota co-evolves with the host and plays an important role in the host's health, immunity, and nutrient absorption. Wild boars are the ancestors of domestic pigs. During the long evolutionary process, the physiological structure and living habits of modern pigs have undergone tremendous changes. However, there are few studies on the evolution of gut microbiota of wild boars and domestic pigs. In this study, by comparing the changes in the composition and function of the gut microbiota of wild boars and domestic pigs, it was found that there were significant differences between the two groups, which indicated that the gut microbiota had changed during the evolution process. This study provides some data references for the evolution of gut microbiota.

Abstract

Gut microbiota diversity is a result of co-evolution between microorganisms and their hosts. However, there are few studies on the evolution of the gut microbiota of wild boars and domestic pigs. Therefore, this study aimed to analyze the composition and function of the gut microbiota of wild boars and domestic pigs using 16S rRNA gene V3-V4 region sequencing, 16S rRNA gene full-length sequencing, and metagenomic sequencing. This study showed that after a long evolution, as compared to wild boars, the domestic pigs exhibited significantly increased relative abundances of Lactobacillus, Lactobacillus reuteri, Lactobacillus johnsonii, Lactobacillus sp.DJF_WC5, and Lactobacillus; s_uncultured bacterium, while the relative abundances of Bifidobacterium and Methanococcaceae decreased significantly. In addition, the relative abundances of “carbohydrate metabolism”, “starch and sucrose metabolism”, “valine, leucine, and isoleucine biosynthesis”, “lysine biosynthesis”, and starch-degrading CAZymes were significantly increased in the domestic pigs, while the relative abundances of “environmental adaptation”, “immune system”, “fatty acid degradation and synthesis”, and cellulose-hemicellulose-degrading CAZymes were significantly increased in the wild boars. Finally, the diversity of ARGs and the “antimicrobial resistance genes” in domestic pigs also increased significantly. This study illustrates that the gut microbiota composition and function of wild boars and domestic pigs changed during the long evolution process. These findings provide a basic research theory for the evolution of gut microbiota and the treatment of health and disease.

Lysine Dipeptide Enhances Gut Structure and Whole-Body Protein Synthesis in Neonatal Piglets with Intestinal Atrophy

BACKGROUND

Parenteral nutrition (PN) is often a necessity for preterm infants; however, prolonged PN leads to gut atrophy, weakened gut barrier function, and a higher risk of intestinal infections. Peptide transporter-1 (PepT1) is a di- or tripeptide transporter in the gut and, unlike other nutrient transporters, its activity is preserved with the onset of intestinal atrophy from PN. As such, enteral amino acids in the form of dipeptides may be more bioavailable than free amino acids when atrophy is present.

OBJECTIVES

In Yucatan miniature piglets with PN-induced intestinal atrophy, we sought to determine the structural and functional effects of enteral refeeding with lysine as a dipeptide, compared to free L-lysine.

METHODS

Piglets aged 7-8 days were PN-fed for 4 days to induce intestinal atrophy, then were refed with enteral diets with equimolar lysine supplied as lysyl-lysine (Lys-Lys; n = 7), free lysine (n = 7), or Lys-Lys with glycyl-sarcosine (n = 6; to determine whether competitive inhibition of Lys-Lys uptake would abolish PepT1-mediated effects). The diets provided lysine at 75% of the requirement and were gastrically delivered for a total of 18 hours. Whole-body and tissue-specific protein synthesis, as well as indices for gut structure and barrier function, were measured.

RESULTS

The villus height, mucosal weight, and free lysine concentration were higher in the Lys-Lys group compared to the other 2 groups (P < 0.05). Lysyl-lysine led to greater whole-body protein synthesis compared to free lysine (P < 0.05). Mucosal myeloperoxidase activity was lower in the Lys-Lys group (P < 0.05), suggesting less inflammation. The inclusion of glycyl-sarcosine with Lys-Lys abolished the dipeptide effects on whole-body and tissue-specific protein synthesis (P < 0.05), suggesting that improved lysine availability was mediated by PepT1.

CONCLUSIONS

Improved intestinal structure and whole-body protein synthesis suggests that feeding strategies designed to exploit PepT1 may help to avoid adverse effects when enteral nutrition is reintroduced into the compromised guts of neonatal piglets.

Porcine Intestinal Organoids: Overview of the State of the Art

The intestinal tract is a crucial part of the body for growth and development, and its dysregulation can cause several diseases. The lack of appropriate in vitro models hampers the development of effective preventions and treatments against these intestinal tract diseases. Intestinal organoids are three-dimensional (3D) polarized structures composed of different types of cells capable of self-organization and self-renewal, resembling their organ of origin in architecture and function. Porcine intestinal organoids (PIOs) have been cultured and are used widely in agricultural, veterinary, and biomedical research. Based on the similarity of the genomic sequence, anatomic morphology, and drug metabolism with humans and the difficulty in obtaining healthy human tissue, PIOs are also considered ideal models relative to rodents. In this review, we summarize the current knowledge on PIOs, emphasizing their culturing, establishment and development, and applications in the study of host–microbe interactions, nutritional development, drug discovery, and gene editing potential.

Evaluation of essential fatty acids in lactating sow diets on sow reproductive performance, colostrum and milk composition, and piglet survivability

Mixed parity sows (n=3,451; PIC, Hendersonville, TN; parities 2 through 9) and their litters were used to evaluate the effects of essential fatty acid (EFA) intake on sow reproductive performance, piglet growth and survivability, and colostrum and milk composition. Our hypothesis, like observed in earlier research, was that increasing linoleic acid (LA) and α-linolenic acid (ALA) would improve sow and litter performance. At approximately d 112 of gestation, sows were randomly assigned within parity groups to 1 of 4 corn-soybean meal-wheat-based lactation diets that contained 0.5 (Control) or 3% choice white grease (CWG), 3% soybean oil (SO), or a combination of 3% soybean oil and 2% choice white grease (Combination). Thus, sows were provided diets with low LA and ALA in diets with CWG or high LA and ALA in diets that included soybean oil. Sows received their assigned EFA treatments until weaning and were then fed a common gestation and lactation diet in the subsequent reproductive cycle. Average daily feed intake during the lactation period increased (P &lt; 0.05) for sows fed the Combination and CWG diets compared to sows fed the Control or SO diet. However, daily LA and ALA intakes of sows fed the Combination and SO diets were still greater (P &lt; 0.05) than those of sows fed 0.5 or 3% CWG. Overall, sows consuming high EFA from the Combination or SO diets produced litters with heavier (P &lt; 0.05) piglet weaning weights and greater (P &lt; 0.05) litter ADG when compared to litters from sows fed diets with CWG that provided low EFA. Despite advantages in growth performance, there was no impact of sow EFA intake on piglet survivability (P &gt; 0.10). Additionally, lactation diet EFA composition did not influence sow colostrum or milk dry matter, crude protein, or crude fat content (P &gt; 0.10). However, LA and ALA content in colostrum and milk increased (P &lt; 0.05) in response to elevated dietary EFA from SO. There was no evidence for differences (P &gt; 0.10) in subsequent sow reproductive or litter performance due to previous lactation EFA intake. In conclusion, increased LA and ALA intake provided by soybean oil during lactation increased overall litter growth and pig weaning weights, reduced sow ADFI, but did not affect piglet survivability or subsequent performance of sows.

Sialic acid, the secret gift for the brain

The human brain grows rapidly in early life which requires adequate nutrition. Human milk provides optimal nutrition for the developing brain, and breastfeeding significantly improves the cognition development of infants. These benefits have been largely attributed to human milk oligosaccharides (HMOS), associated with sialic acid (Sia). Subsequently, sialylated HMOS present a vital source of exogenous Sia to infants. Sialic acid is a key molecule essential for proper development of gangliosides, and therefore critical in brain development and function. Recent pre-clinical studies suggest dietary supplementation with Sia or sialylated oligosaccharides enhances intelligence and cognition performance in early and later life. Furthermore, emerging evidence suggests the involvement of Sia in brain homeostasis and disbalance correlates with common pathologies such as Alzheimer's disease (AD). Therefore, this review will discuss early brain health and development and the role of Sia in this process. Additionally, studies associating breastfeeding and specific HMOS to benefits in cognitive development are critically assessed. Furthermore, the review will assess studies implying the potential role of HMOS and microbiota in brain development via the gut-brain axis. Finally, the review will summarize recent advances regarding the role of Sia in neurodegenerative disease in later life and potential roles of dietary Sia sources.

Gut Microbiota Implications for Health and Welfare in Farm Animals: A Review

Simple Summary

Farm animal health and welfare have been paid increasing concern in the world, which is generally assessed by the measurements of physical health, immune response, behavior, and physiological indicators, such as stress-related hormone, cortisone, and norepinephrine. Gut microbiota as a “forgotten organ” has been reported for its great influence on the host phenotypes through the immune, neural, and endocrine pathways to affect the host health and behavior. In addition, fecal microbiota transplantation as a novel approach is applied to regulating the composition and function of the recipient farm animals. In this review, we summarized recent studies that gut microbiota influenced health, immunity, behavior, and stress response, as well as the progress of fecal microbiota transplantation in farm animals. The review will provide new insights into the measurement of farm animal health and welfare concerning gut microbiota, and the implication of fecal microbiota transplantation to improve productivity, health, and welfare. Above all, this review suggests that gut microbiota is a promising field to evaluate and improve animal welfare.

Abstract

In the past few decades, farm animal health and welfare have been paid increasing concern worldwide. Farm animal health and welfare are generally assessed by the measurements of physical health, immune response, behavior, and physiological indicators. The gut microbiota has been reported to have a great influence on host phenotypes, possibly via the immune processes, neural functions, and endocrine pathways, thereby influencing host phenotypes. However, there are few reviews regarding farm animals’ health and welfare status concerning the gut microbiota. In this point of view, (1) we reviewed recent studies showing that gut microbiota (higher alpha diversity, beneficial composition, and positive functions) effectively influenced health characteristics, immunity, behaviors, and stress response in farm animals (such as pigs, chickens, and cows), which would provide a novel approach to measure and evaluate the health status and welfare of farm animals. In addition, fecal microbiota transplantation (FMT) as one of the methods can modulate the recipient individual’s gut microbiota to realize the expected phenotype. Further, (2) we highlighted the application of FMT on the improvement of the production performance, the reduction in disease and abnormal behavior, as well as the attenuation of stress in farm animals. It is concluded that the gut microbiota can be scientifically used to assess and improve the welfare of farm animals. Moreover, FMT may be a helpful strategy to reduce abnormal behavior and improve stress adaption, as well as the treatment of disease for farm animals. This review suggests that gut microbiota is a promising field to evaluate and improve animal welfare.

Intermittent bolus feeding does not enhance protein synthesis, myonuclear accretion, or lean growth more than continuous feeding in a premature piglet model

Optimizing enteral nutrition for premature infants may help mitigate extrauterine growth restriction and adverse chronic health outcomes. Previously, we showed in neonatal pigs born at term that lean growth is enhanced by intermittent bolus compared with continuous feeding. The objective was to determine if prematurity impacts how body composition, muscle protein synthesis, and myonuclear accretion respond to feeding modality. Following preterm delivery, pigs were fed equivalent amounts of formula delivered either as intermittent boluses (INT; n = 30) or continuously (CONT; n = 14) for 21 days. Body composition was measured by dual-energy X-ray absorptiometry (DXA) and muscle growth was assessed by morphometry, myonuclear accretion, and satellite cell abundance. Tissue anabolic signaling and fractional protein synthesis rates were determined in INT pigs in postabsorptive (INT-PA) and postprandial (INT-PP) states and in CONT pigs. Body weight gain and composition did not differ between INT and CONT pigs. Longissimus dorsi (LD) protein synthesis was 34% greater in INT-PP than INT-PA pigs (P < 0.05) but was not different between INT-PP and CONT pigs. Phosphorylation of 4EBP1 and S6K1 and eIF4E·eIF4G abundance in LD paralleled changes in LD protein synthesis. Satellite cell abundance, myonuclear accretion, and fiber cross-sectional area in LD did not differ between groups. These results suggest that, unlike pigs born at term, intermittent bolus feeding does not enhance lean growth more than continuous feeding in pigs born preterm. Premature birth attenuates the capacity of skeletal muscle to respond to cyclical surges in insulin and amino acids with intermittent feeding in early postnatal life.NEW & NOTEWORTHY Extrauterine growth restriction often occurs in premature infants but may be mitigated by optimizing enteral feeding strategies. We show that intermittent bolus feeding does not increase skeletal muscle protein synthesis, myonuclear accretion, or lean growth more than continuous feeding in preterm pigs. This attenuated anabolic response of muscle to intermittent bolus feeding, compared with previous observations in pigs born at term, may contribute to deficits in lean mass that many premature infants exhibit into adulthood.

Use of Agriculturally Important Animals as Models in Biomedical Research

Livestock have contributed significantly to advances in biomedicine and offer unique advantages over rodent models. The human is the ideal biomedical model; however, ethical reasons limit the testing of hypotheses and treatments in humans. Rodent models are frequently used as alternatives to humans due to size, low cost, and ease of genetic manipulation, and have contributed tremendously to our understanding of human health and disease. However, the use of rodents in translational research pose challenges for researchers due to physiological differences to humans. The use of livestock species as biomedical models can address these challenges as livestock have several similarities to human anatomy, physiology, genetics, and metabolism and their larger size permits collection of more frequent and often larger samples. Additionally, recent advances in genetics in livestock species allow for studies in genomics, proteomics, and metabolomics, which have the added benefit of applications to both humans in biomedical research and livestock in improving production. In this review, we provide an overview of scientific findings using livestock and benefits of each model to the livestock industry and to biomedical research.

Sialylated milk oligosaccharides alter neurotransmitters and brain metabolites in piglets: an In vivo magnetic resonance spectroscopic (MRS) study

Background: Human milk contains high concentrations and diversity of sialylated oligosaccharides that have multifunctional health benefits, however, their potential role in optimizing neurodevelopment remains unknown.Objective: To investigate the effect of sialylated milk oligosaccharides (SMOS) intervention on neurotransmitters and brain metabolites in piglets.Methods: 3-day-old piglets were randomly allocated to one of three groups and fed either standard sow milk replacer (SMR) alone (n = 15), SMR supplemented with sialyllactose 9.5 g/kg (SL, n = 16) or a combination of SL and 6'-sialyllactosamine 9.5 g/kg (SL/SLN, n = 15) for 35 days. Brain spectra were acquired using a 3T Magnetic Resonance Spectroscopic (MRS) system.Results: SMOS fed piglets were observed to have significantly increased the absolute levels of myo-inositol (mIns) and glutamate + glutamine (Glx), in particular, the SL/SLN group. Similar findings were found in the relative amount of these metabolites calculated as ratios to creatine (Cr), choline (Cho) and N-acetylaspartate (NAA) respectively (P < .05). In addition, there were significant positive correlations of brain NAA, total NAA (TNAA), mIns, total Cho (TCho), total Cr (TCr), scyllo-Inositol (SI) and glutathione (Glth) with total white matter volume; Glu and SI with whole brain volume; and SI with whole brain weight respectively (P < .01). SLN and 3'SL intake were closely correlated with the levels of brain Glu, mlns and Glx in the treatment groups only (P < .01-.05).Conclusions: We provide in vivo evidences that milk SMOS can alter many important brain metabolites and neurotransmitters required for optimizing neurodevelopment in piglets, an animal model of human infants.

Dietary sialylated oligosaccharides in early-life may promote cognitive flexibility during development in context of obesogenic dietary intake

Introduction: Oligosaccharides found in mammalian milk have shown the potential to alter brain development across multiple species. The diversity and concentration of these oligosaccharides is species-specific and varies greatly between individuals, thus understanding their role in cognitive development is warranted. We investigated the impact of early life dietary fucosylated/neutral or sialylated human milk oligosaccharides (HMO) on behaviours in tasks assessing anxiety, motivation, appetite, learning, and memory.Methods: Sixty-four female Göttingen minipigs were artificially reared from 2 weeks postnatal and provided milk replacers. The study used four groups: no additional oligosaccharides (Con), fucosylated and neutral oligosaccharides (FN, 4 g/L), sialylated oligosaccharides (SL, 0.68 g/L), or both FN and SL (FN + SL, 4 g/L) from 2 to 11 weeks postnatal. One reference group was sow-reared. Weaning occurred between 10 and 11 weeks postnatal, and thereafter an obesogenic diet was provided. Behavioral tasks were conducted over three periods: 1) 0-11 weeks; 2) 16-29 weeks; 3) 39-45 weeks. Tasks included a spatial holeboard task, open field task, exposure to a novel object, runway task, single-feed task, and home pen behaviour observation.Results: In the holeboard, the SL group demonstrated improved reference memory during reversal trials between 16-29 weeks. All groups demonstrated equivalent behavior in open field, novel object, runway, and single-feed tasks, as well as in their home pens (Ps > 0.05).Discussion: These results suggest that early life dietary intake of sialylated oligosaccharides may provide an improvement to cognition during the equivalent developmental stage of adolescence.

Brief Research Report: Estimation of the Protein Digestibility-Corrected Amino Acid Score of Defatted Walnuts

Introduction: Walnuts are considered a good source of essential fatty acids, which is unique among tree nuts. Walnuts are also composed of about 10–15% protein, but the quality of this protein has not been evaluated. Pistachios and almonds have been evaluated for their protein content using a protein digestibility-corrected amino acid score (PDCAAS), but it is unclear how the quality of protein in walnuts relates to that in other commonly consumed tree nuts. The objective of this study was to substantiate the protein quality of walnuts by determining their PDCAAS.

Methods: A small, 10-day dietary intervention trial was conducted using male Sprague-Dawley rats (n = 8, 4 per group) with two diets: a nitrogen-free diet and a diet containing protein exclusively from defatted walnuts. Feed intake and fecal output of nitrogen were measured to estimate the true protein digestibility, and the amino acid compositions of walnuts compared to child and adult populations were used to calculate amino acid scores (AAS) and PDCAAS.

Results: The true protein digestibility score of raw walnuts was calculated to be 86.22%. Raw walnuts contained 15.6 g protein/g walnut with AAS of 0.45 and 0.63 for children aged 6 months to 3 years and 3–10 years, respectively. For each population, a PDCAAS of 39 and 46% was calculated, respectively, using a protein conversion constant of 5.30. Using a protein constant of 6.25, a PDCAAS of 39% (6 months - 3 years) or 46% (3-10 years) was calculated.

Conclusions: This is the first known assessment of the PDCAAS of walnuts. Like almonds, they appear to have a low-to-moderate score, indicating they are not a quality source of protein.

Dietary Tryptophan Supplementation Alters Fat and Glucose Metabolism in a Low-Birthweight Piglet Model

Low birthweight (LBW) is associated with metabolic complications, such as glucose and lipid metabolism disturbances in early life. The objective of this study was to assess: (1) the effect of dietary tryptophan (Trp) on glucose and fat metabolism in an LBW piglet model, and (2) the role peripheral 5-hydroxytryptamine type 3 (5HT3) receptors in regulating the feeding behavior in LBW piglets fed with Trp-supplemented diets. Seven-day-old piglets were assigned to 4 treatments: normal birthweight-0%Trp (NBW-T0), LBW-0%Trp (LBW-T0), LBW-0.4%Trp (LBW-T0.4), and LBW-0.8%Trp (LBW-T0.8) for 3 weeks. Compared to LBW-T0, the blood glucose was decreased in LBW-T0.8 at 60 min following the meal test, and the triglycerides were lower in LBW-T0.4 and LBW-T0.8. Relative to LBW-T0, LBW-T0.8 had a lower transcript and protein abundance of hepatic glucose transporter-2, a higher mRNA abundance of glucokinase, and a lower transcript of phosphoenolpyruvate carboxykinase. LBW-T0.4 tended to have a lower protein abundance of sodium-glucose co-transporter 1 in the jejunum. In comparison with LBW-T0, LBW-T0.4 and LBW-T0.8 had a lower transcript of hepatic acetyl-CoA carboxylase, and LBW-T0.4 had a higher transcript of 3-hydroxyacyl-CoA dehydrogenase. Blocking 5-HT3 receptors with ondansetron reduced the feed intake in all groups, with a transient effect on LBW-T0, but more persistent effect on LBW-T0.8 and NBW-T0. In conclusion, Trp supplementation reduced the hepatic lipogenesis and gluconeogenesis, but increased the glycolysis in LBW piglets. Peripheral serotonin is likely involved in the regulation of feeding behavior, particularly in LBW piglets fed diets supplemented with a higher dose of Trp.

Potential Benefits of Bovine Colostrum in Pediatric Nutrition and Health

Bovine colostrum (BC), the first milk produced from cows after parturition, is increasingly used as a nutritional supplement to promote gut function and health in other species, including humans. The high levels of whey and casein proteins, immunoglobulins (Igs), and other milk bioactives in BC are adapted to meet the needs of newborn calves. However, BC supplementation may improve health outcomes across other species, especially when immune and gut functions are immature in early life. We provide a review of BC composition and its effects in infants and children in health and selected diseases (diarrhea, infection, growth-failure, preterm birth, necrotizing enterocolitis (NEC), short-bowel syndrome, and mucositis). Human trials and animal studies (mainly in piglets) are reviewed to assess the scientific evidence of whether BC is a safe and effective antimicrobial and immunomodulatory nutritional supplement that reduces clinical complications related to preterm birth, infections, and gut disorders. Studies in infants and animals suggest that BC should be supplemented at an optimal age, time, and level to be both safe and effective. Exclusive BC feeding is not recommended for infants because of nutritional imbalances relative to human milk. On the other hand, adverse effects, including allergies and intolerance, appear unlikely when BC is provided as a supplement within normal nutrition guidelines for infants and children. Larger clinical trials in infant populations are needed to provide more evidence of health benefits when patients are supplemented with BC in addition to human milk or formula. Igs and other bioactive factors in BC may work in synergy, making it critical to preserve bioactivity with gentle processing and pasteurization methods. BC has the potential to become a safe and effective nutritional supplement for several pediatric subpopulations.

Gut microbiota absence and transplantation affect growth and intestinal functions: An investigation in a germ-free pig model

This study was conducted to investigate host–microbiota interactions and explore the effects of maternal gut microbiota transplantation on the growth and intestinal functions of newborns in a germ-free (GF) pig model. Twelve hysterectomy-derived GF Bama piglets were reared in 6 sterile isolators. Among them, 6 were considered as the GF group, and the other 6 were orally inoculated with healthy sow fecal suspension as fecal microbiota transplanted (FMT) group. Another 6 piglets from natural birth were regarded as the conventional (CV) group. The GF and FMT groups were hand-fed with Co60-γ-irradiated sterile milk powder, while the CV group was reared by lactating Bama sows. All groups were fed for 21 days. Then, all piglets and then were switched to sterile feed for another 21 days. Results showed that the growth performance, nutrient digestibility, and concentrations of short-chain fatty acids in the GF group decreased (P < 0.05). Meanwhile, the serum urea nitrogen concentration and digesta pH values in the GF group increased compared with those in the FMT and CV groups (P < 0.05). Compared with the CV group, the GF group demonstrated upregulation in the mRNA expression levels of intestinal barrier function-related genes in the small intestine (P < 0.05). In addition, the mRNA abundances of intestinal development and absorption-related genes in the small intestine and colon were higher in the GF group than in the CV and FMT groups (P < 0.05). The FMT group exhibited greater growth performance, lipase activity, and nutrient digestibility (P < 0.05), higher mRNA expression levels of intestinal development and barrier-related genes in the small intestine (P < 0.05), and lower mRNA abundances of pro-inflammatory factor in the colon and jejunum (P < 0.05) than the CV group. In conclusion, the absence of gut microbes impaired the growth and nutrient digestibility, and healthy sow gut microbiota transplantation increased the growth and nutrient digestibility and improved the intestinal development and barrier function of newborn piglets, indicating the importance of intestinal microbes for intestinal development and functions.

Young Domestic Pigs (Sus scrofa) Can Perform Pavlovian Eyeblink Conditioning

Introduction: Pigs have been an increasingly popular preclinical model in nutritional neuroscience, as their anatomy, physiology, and nutrition requirements are highly comparable to those of humans. Eyeblink conditioning is one of the most well-validated behavioral paradigms in neuroscience to study underlying mechanisms of learning and memory formation in the cerebellum. Eyeblink conditioning has been performed in many species but has never been done on young pigs. Therefore, our aim here was to develop and validate an eyeblink conditioning paradigm in young pigs. Method: Eighteen intact male pigs were artificially reared from postnatal day 2-30. The eyeblink conditioning setup consisted of a sound-damping box with a hammock that pigs were placed in, which allowed the pig to remain comfortable yet maintain a typical range of head motion. In a delay conditioning paradigm, the conditional stimulus (CS) was a 550 ms blue light-emitting diode (LED), the unconditional stimulus (US) was a 50 ms eye air-puff, the CS-US interval was 500 ms. Starting at postnatal day 14, pigs were habituated for 5 days to the eyeblink conditioning setup, followed by 5 daily sessions of acquisition training (40 paired CS-US trials each day). Results: The group-averaged amplitude of conditioned eyelid responses gradually increased over the course of the 5 days of training, indicating that pigs learned to make the association between the LED light CS and the air-puff US. A similar increase was found for the conditioned response (CR) probability: the group-averaged CR probability on session 1 was about 12% and reached a CR probability of 55% on day 5. The latency to CR peak time lacked a temporal preference in the first session but clearly showed preference from the moment that animals started to show more CRs in session 2 and onwards whereby the eyelid was maximally closed exactly at the moment that the US would be delivered. Conclusion: We concluded that 3-week-old pigs have the capability of performing in a cerebellar classical conditioning task, demonstrating for the first time that eyeblink conditioning in young pigs has the potential to be a valuable behavioral tool to measure neurodevelopment.

Probiotics, Prebiotics and Epithelial Tight Junctions: A Promising Approach to Modulate Intestinal Barrier Function

Disruptions in the intestinal epithelial barrier can result in devastating consequences and a multitude of disease syndromes, particularly among preterm neonates. The association between barrier dysfunction and intestinal dysbiosis suggests that the intestinal barrier function is interactive with specific gut commensals and pathogenic microbes. In vitro and in vivo studies demonstrate that probiotic supplementation promotes significant upregulation and relocalization of interepithelial tight junction proteins, which form the microscopic scaffolds of the intestinal barrier. Probiotics facilitate some of these effects through the ligand-mediated stimulation of several toll-like receptors that are expressed by the intestinal epithelium. In particular, bacterial-mediated stimulation of toll-like receptor-2 modulates the expression and localization of specific protein constituents of intestinal tight junctions. Given that ingested prebiotics are robust modulators of the intestinal microbiota, prebiotic supplementation has been similarly investigated as a potential, indirect mechanism of barrier preservation. Emerging evidence suggests that prebiotics may additionally exert a direct effect on intestinal barrier function through mechanisms independent of the gut microbiota. In this review, we summarize current views on the effects of pro- and prebiotics on the intestinal epithelial barrier as well as on non-epithelial cell barrier constituents, such as the enteric glial cell network. Through continued investigation of these bioactive compounds, we can maximize their therapeutic potential for preventing and treating gastrointestinal diseases associated with impaired intestinal barrier function and dysbiosis.

Short-chain fatty acids can improve lipid and glucose metabolism independently of the pig gut microbiota

BACKGROUND

Previous studies have shown that exogenous short-chain fatty acids (SCFAs) introduction attenuated the body fat deposition in conventional mice and pigs. However, limited studies have evaluated the effects of exogenously introduced SCFAs on the lipid and glucose metabolism independently of the gut microbiota. This study was to investigate the effects of exogenous introduction of SCFAs on the lipid and glucose metabolism in a germ-free (GF) pig model.

METHODS

Twelve hysterectomy-derived newborn pigs were reared in six sterile isolators. All pigs were hand-fed with sterile milk powder for 21 d, then the sterile feed was introduced to pigs for another 21 d. In the second 21-d period, six pigs were orally administrated with 25 mL/kg sterile saline per day and considered as the GF group, while the other six pigs were orally administrated with 25 mL/kg SCFAs mixture (acetic, propionic, and butyric acids, 45, 15, and 11 mmol/L, respectively) per day and regarded as FA group.

RESULTS

Orally administrated with SCFAs tended to increase the adiponectin concentration in serum, enhance the CPT-1 activity in longissimus dorsi, and upregulate the ANGPTL4 mRNA expression level in colon (P < 0.10). Meanwhile, the mRNA abundances of ACC, FAS, and SREBP-1C in liver and CD36 in longissimus dorsi of the FA group were decreased (P < 0.05) compared with those in the GF group. Besides, the mRNA expression of PGC-1α in liver and LPL in longissimus dorsi tended to (P < 0.10) upregulate and downregulate respectively in the FA group. Moreover, oral administration of SCFAs tended to increase the protein level of GPR43 (P < 0.10) and decrease the protein level of ACC (P < 0.10) in liver. Also, oral administration of SCFAs upregulated the p-AMPK/AMPK ratio and the mRNA expressions of GLUT-2 and GYS2 in liver (P < 0.05). In addition, the metabolic pathway associated with the biosynthesis of unsaturated fatty acids was most significantly promoted (P < 0.05) by oral administration of SCFAs.

CONCLUSIONS

Exogenous introduction of SCFAs might attenuate the fat deposition and to some extent improve the glucose control in the pig model, which occurred independently of the gut microbiota.

Safety and Efficacy of Sodium and Potassium Arachidonic Acid Salts in the Young Pig

Arachidonic acid (ARA; 20:4n6) and docosahexaenoic acid (DHA; 22:6n3) are polyunsaturated fatty acids (FA) naturally present in breast milk and added to most North American infant formulas (IF). We investigated the safety and efficacy of novel sodium and potassium salts of arachidonic acid as bioequivalent to support tissue levels of ARA comparable to the parent oil; M. alpina oil (Na-ARA and K-ARA) and including a Na-DHA group. Pigs of both sexes were randomized to one of five dietary treatments (n = 16 per treatment; 8 male and 8 female) from postnatal day 2 to 23. ARA and DHA were included as either triglyceride (TG) or salt. Target dietary ARA/DHA concentrations as percent of total FA by weight were as follows: TT (0.47 TG/0.32 TG), NaT (0.47 Na-salt/0.32 TG), KT (0.47 K-salt/0.32 TG), and Na0 (0.47 Na-salt/0.00), NaNa (0.47 Na-salt/0.32 Na-salt). The primary outcome in this study was bioequivalence of ARA brain accretion. Growth performance; blood and tissue fatty acid levels; liver histology; complete blood cell counts; and serum chemistries were all evaluated. Overall, diets containing test sources of ARA and DHA did not affect growth performance; liver histology; or substantially influence hematological outcomes as compared with TT. The results confirm that the use of Na and K salt forms of ARA yield bioequivalent ARA accretion in the cerebral cortex and retinal tissue compared to TG-ARA. These findings confirm that use of Na-ARA and K-ARA salts in the young pig was safe and nutritionally bioequivalent to TG-ARA for critical neural tissues.

Swine as biomedical animal model for T-cell research-Success and potential for transmittable and non-transmittable human diseases

Swine is biologically one of the most relevant large animal models for biomedical research. With its use as food animal that can be exploited as a free cell and tissue source for research and its high susceptibility to human diseases, swine additionally represent an excellent option for both the 3R principle and One Health research. One of the previously most limiting factors of the pig model was its arguably limited immunological toolbox. Yet, in the last decade, this toolbox has vastly improved including the ability to study porcine T-cells. This review summarizes the swine model for biomedical research with focus on T cells. It first contrasts the swine model to the more commonly used mouse and non-human primate model before describing the current capabilities to characterize and extend our knowledge on porcine T cells. Thereafter, it not only reflects on previous biomedical T-cell research but also extends into areas in which more in-depth T-cell analyses could strongly benefit biomedical research. While the former should inform on the successes of biomedical T-cell research in swine, the latter shall inspire swine T-cell researchers to find collaborations with researchers working in other areas - such as nutrition, allergy, cancer, transplantation, infectious diseases, or vaccine development.

Maternal antibiotic treatment affects offspring gastric sensing for umami taste and ghrelin regulation in the pig

Background

Scarce is knowledge on the process regulating the development of acid secretion, orexigenic signaling, and chemosensing in the stomach of young pigs. Changes of early microbial encounters by suckling pigs can interact with the gut maturation, by the induction of different molecular signaling. Our goal was to assess if the age of offspring and the maternal environment, influenced by sow antibiotic treatment peripartum, could affect gastric morphology and the expression of genes involved in the control of hydrochloric secretion, feed intake, taste, and inflammation in offspring stomach.

Methods

84 pigs from sows fed a diet with amoxicillin (on –d10 to +d21 from farrowing, ANT) or without (CON) were sacrificed at d14, d21, d28 (weaning) or d42. Samples of oxyntic (OXY), pyloric (PY) and cardiac mucosae close to OXY were collected and parietal and enteroendocrine cells (EECs) were counted. Relative gene expression of a set of 11 key genes (ATP4A, SSTR2, GAST, GHRL, MBOAT4, PCSK1, GNAT1, TAS1R1, TAS1R3, IL8 and TNF) was assessed by qRT-PCR. In addition, 40 offspring obtained from the same ANT and CON sows were offered a normal or a fat-enriched diet for 4 weeks between 140 and 169 d of age, and then OXY and PY were sampled.

Results

The number of parietal and EECs increased with age (P < 0.001). ATP4A increased with age (within suckling, P = 0.043, post-weaning vs. suckling, P < 0.001), SSTR2 increased only after weaning (P < 0.001). In OXY, GHRL increased during suckling (P = 0.012), and post-weaning as a trend (P = 0.088). MBOAT4 tended to increase during suckling (P = 0.062). TAS1R1 increased from suckling to post-weaning period (P =0.001) and was lower in ANT offspring (P = 0.013). GNAT1 in PY was higher in ANT offspring (P = 0.041). Antibiotic treatment of sows peripartum increased expression of GHRL and MBOAT4 in OXY of growing-finishing offspring aged 5 months.

Conclusions

Data show that sensing for umami taste and ghrelin regulation can be affected by maternal environment, but the development of acid secretion, orexigenic signaling and taste perception in the stomach are mostly developmentally controlled.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00557-3.

Prematurity blunts the insulin- and amino acid-induced stimulation of translation initiation and protein synthesis in skeletal muscle of neonatal pigs

Extrauterine growth restriction in premature infants is largely attributed to reduced lean mass accretion and is associated with long-term morbidities. Previously, we demonstrated that prematurity blunts the feeding-induced stimulation of translation initiation signaling and protein synthesis in skeletal muscle of neonatal pigs. The objective of the current study was to determine whether the blunted feeding response is mediated by reduced responsiveness to insulin, amino acids, or both. Pigs delivered by cesarean section preterm (PT; 103 days, n = 25) or at term (T; 112 days, n = 26) were subject to euinsulinemic-euaminoacidemic-euglycemic (FAST), hyperinsulinemic-euaminoacidemic-euglycemic (INS), or euinsulinemic-hyperaminoacidemic-euglycemic (AA) clamps four days after delivery. Indices of mechanistic target of rapamycin complex 1 (mTORC1) signaling and fractional protein synthesis rates were measured after 2 h. Although longissimus dorsi (LD) muscle protein synthesis increased in response to both INS and AA, the increase was 28% lower in PT than in T. Upstream of mTORC1, Akt phosphorylation, an index of insulin signaling, was increased with INS but was 40% less in PT than in T. The abundances of mTOR·RagA and mTOR·RagC, indices of amino acid signaling, increased with AA but were 25% less in PT than in T. Downstream of mTORC1, eIF4E·eIF4G abundance was increased by both INS and AA but attenuated by prematurity. These results suggest that preterm birth blunts both insulin- and amino acid-induced activation of mTORC1 and protein synthesis in skeletal muscle, thereby limiting the anabolic response to feeding. This anabolic resistance likely contributes to the high prevalence of extrauterine growth restriction in prematurity.NEW & NOTEWORTHY Extrauterine growth faltering is a major complication of premature birth, but the underlying cause is poorly understood. Our results demonstrate that preterm birth blunts both the insulin-and amino acid-induced activation of mTORC1-dependent translation initiation and protein synthesis in skeletal muscle, thereby limiting the anabolic response to feeding. This anabolic resistance likely contributes to the reduced accretion of lean mass and extrauterine growth restriction of premature infants.

Dairy-Derived Emulsifiers in Infant Formula Show Marginal Effects on the Plasma Lipid Profile and Brain Structure in Preterm Piglets Relative to Soy Lecithin

Breastfed infants have higher intestinal lipid absorption and neurodevelopmental outcomes compared to formula-fed infants, which may relate to a different surface layer structure of fat globules in infant formula. This study investigated if dairy-derived emulsifiers increased lipid absorption and neurodevelopment relative to soy lecithin in newborn preterm piglets. Piglets received a formula diet containing soy lecithin (SL) or whey protein concentrate enriched in extracellular vesicles (WPC-A-EV) or phospholipids (WPC-PL) for 19 days. Both WPC-A-EV and WPC-PL emulsions, but not the intact diets, increased in vitro lipolysis compared to SL. The main differences of plasma lipidomics analysis were increased levels of some sphingolipids, and lipid molecules with odd-chain (17:1, 19:1, 19:3) as well as mono- and polyunsaturated fatty acyl chains (16:1, 20:1, 20:3) in the WPC-A-EV and WPC-PL groups and increased 18:2 fatty acyls in the SL group. Indirect monitoring of intestinal triacylglycerol absorption showed no differences between groups. Diffusor tensor imaging measurements of mean diffusivity in the hippocampus were lower for WPC-A-EV and WPC-PL groups compared to SL indicating improved hippocampal maturation. No differences in hippocampal lipid composition or short-term memory were observed between groups. In conclusion, emulsification of fat globules in infant formula with dairy-derived emulsifiers altered the plasma lipid profile and hippocampal tissue diffusivity but had limited effects on other absorptive and learning abilities relative to SL in preterm piglets.

Exogenous infusion of short-chain fatty acids can improve intestinal functions independently of the gut microbiota

The present experiment was conducted to investigate the effects of exogenously infused short-chain fatty acids (SCFAs) on the growth development and intestinal functions in a germ-free (GF) pig model. Twelve hysterectomy-derived newborn piglets were reared in six sterile isolators. All piglets were hand-fed Co60-γ-irradiated sterile milk powder for 21 d and then were switched to sterile feed for another 21 d. During the second 21-d period, GF piglets (n = 6) were orally infused with 25 mL/kg sterile saline per day, and SCFA piglets (n = 6) were orally infused with 25 mL/kg SCFAs mixture (acetic, propionic, and butyric acids, 45, 15, and 11 mM, respectively) per day. We observed the concentrations of SCFAs in serum and intestine, and the messenger ribonucleic acid (mRNA) abundance of G-protein-coupled receptor-43 in the ileum was increased (P < 0.05) in the SCFA group. Meanwhile, oral infusion of SCFAs enhanced (P < 0.05) the contents of glucagon-like peptide-2 in the jejunum and serum and tended to increase the villi height in the ileum (P < 0.10). Besides, the activities of lipase, trypsin, sucrase, lactase, Na+-K+-adenosine triphosphatase ([ATPase] P < 0.05), and Ca2+-Mg2+-ATPase (P < 0.10) were stimulated and the mRNA expressions of solute carrier family 7 (SLC7A1) and regeneration protein (REG)-ΙΙΙ γ in the jejunum (P < 0.05) were upregulated in the SCFA group. Additionally, SCFAs infusion downregulated the mRNA abundances of interleukin (IL)-1β and IL-6 in the jejunum, ileum, or colon (P < 0.05) and increased the counts of white blood cell, neutrophils, and lymphocyte in the blood (P < 0.05). Collectively, exogenous infusion of SCFAs might improve intestinal health through promoting intestinal development and absorption function, and enhancing intestinal immune function, and these effects were occur independently of the gut microbiota.

A prospective on multiple biological activities of lactoferrin contributing to piglet welfare

Piglets, especially weaning piglets, show a lower level of immunity and higher morbidity and mortality, owing to their rapid growth, physiological immaturity, and gradual reduction of maternal antibodies, which seriously affects their growth and thus, value. It is important that piglets adapt to nutrient digestion and absorption and develop sound intestinal function and colonization with gut microbiota as soon as possible during their early life stage. Lactoferrin is a natural glycoprotein polypeptide that is part of the transferrin family. It is widely found in mucosal secretions such as saliva and tears, and most highly in milk and colostrum. As a multifunctional bioactive protein and a recommended food additive, lactoferrin is a potential alternative therapy to antibiotics and health promoting additive for piglet nutrition and development. It is expected that lactoferrin, as a natural food additive, could play an important role in maintaining pig health and development. This review examines the following known beneficial effects of lactoferrin: improves the digestion and capacity for absorption in the intestinal tract; promotes the absorption of iron and reduces the incidence of iron deficiency anemia; regulates intestinal function and helps to balance the microbial biota; and enhances the resistance to disease of the piglets via modulating and enhancing the immune system.

Developing a Reference Database for Typical Body and Organ Growth of the Artificially Reared Pig as a Biomedical Research Model

Objectives: The pig is a common model utilized to support substantiation of novel bioactive components in infant formula. However, reference ranges for outcomes to determine safety are unclear. Our objective was to use historical data to objectively define typical body and organ growth metrics of the domesticated pig in research. Methods: Twenty-two studies were compiled to assess typical growth of body and organ weights in young pigs. Metadata were organized to include milk replacer sources, bioactive components, sex, breed, source of herd, feeding regimen, and rearing environment. A combination of statistical models including simple linear regression and linear mixed effect models were used to assess typical growth patterns. Results: Over 18,000 data points from 786 animals were available. In general, minimal differences in the growth of pigs who were male and female, artificially- or sow-reared, or fed ad libitum- or by scheduled-feeding, were observed in the first 30 days of life (P > 0.05). A weight-for-age chart from reference pigs was developed to compare body weights of pigs demonstrating growth characterized as accelerated, typical, reduced, and failure to thrive to illustrate effects of dietary interventions. Distributions of relative brain, liver, and intestine weights (as % of total body weight) were similar between rearing environments and sexes. An alternative bivariate level approach was utilized for the analysis of organ weights. This approach revealed significant biologically-relevant insights into how deficient diets can affect organ weight that a univariate level assessment of weight distribution was unable to detect. Conclusions: Ultimately, these data can be used to better interpret whether bioactive ingredients tested in the pig model affect growth and development within typical reference values for pigs in the first 30 days of life.

A safety evaluation of mixed human milk oligosaccharides in neonatal farm piglets

Human Milk Oligosaccharides (HMOs) are the third most abundant, solid component of human milk after lactose and fat. As novel processes are developed to cost-effectively produce commercial volumes of these oligosaccharides, they are becoming more common components of infant formulas worldwide. The study evaluated the safety of a novel mixture of HMOs in a neonatal piglet model with the objective of identifying potential effects during the sensitive, preweaning developmental stage of life. The mixture of HMOs (HMO MIX 1) was composed of 2′-fucosyllactose (2′-FL), 3-fucosyllactose (3-FL), lacto-N-tetraose (LNT), 3′-sialyllactose (3′-SL), and 6′-sialyllactose (6′-SL), and was administered to 2-day old piglets at either 5.75 or 8.0 g/L for a period of 21 days. Piglets in the 5.75 and 8.0 g/L HMO MIX 1 dosing groups did not exhibit differences in body weight, food consumption, or feed efficiency. Analysis of clinical chemistry parameters on Study Day 7 and Study Day 21 did not demonstrate any effects that could be attributed to HMO MIX 1, nor were there any findings in organ weight, macroscopic, or microscopic inspection of tissues that could be attributed to this oligosaccharide blend. Therefore, since administration of HMO MIX 1 in a liquid diet up to 8.0 g/L resulted in no toxicologically-relevant effects in comparison with animals fed a control diet, this study supports the safety of this ingredient for addition to infant formula products.

Impact of Arachidonic and Docosahexaenoic Acid Supplementation on Neural and Immune Development in the Young Pig

Background: Human milk contains both arachidonic acid (ARA) and docosahexaenoic acid (DHA). Supplementation of infant formula with ARA and DHA results in fatty acid (FA) profiles, neurodevelopmental outcomes, and immune responses in formula-fed infants that are more like those observed in breastfed infants. Consequently, ARA and DHA have been historically added together to infant formula. This study investigated the impact of ARA or DHA supplementation alone or in combination on tissue FA incorporation, immune responses, and neurodevelopment in the young pig.

Methods: Male pigs (N = 48 total) received one of four dietary treatments from postnatal day (PND) 2–30. Treatments targeted the following ARA/DHA levels (% of total FA): CON (0.00/0.00), ARA (0.80/0.00), DHA (0.00/0.80), and ARA+DHA (0.80/0.80). Plasma, red blood cells (RBC), and prefrontal cortex (PFC) were collected for FA analysis. Blood was collected for T cell immunophenotyping and to quantify a panel of immune outcomes. Myelin thickness in the corpus callosum was measured by transmission electron microscopy and pig movement was measured by actigraphy.

Results: There were no differences in formula intake or growth between dietary groups. DHA supplementation increased brain DHA, but decreased ARA, compared with all other groups. ARA supplementation increased brain ARA compared with all other groups but did not affect brain DHA. Combined supplementation increased brain DHA levels but did not affect brain ARA levels compared with the control. Pigs fed ARA or ARA+DHA exhibited more activity than those fed CON or DHA. Diet-dependent differences in activity suggested pigs fed ARA had the lowest percent time asleep, while those fed DHA had the highest. No differences were observed for immune or myelination outcomes.

Conclusion: Supplementation with ARA and DHA did not differentially affect immune responses, but ARA levels in RBC and PFC were reduced when DHA was provided without ARA. Supplementation of either ARA or DHA alone induced differences in time spent asleep, and ARA inclusion increased general activity. Therefore, the current data support the combined supplementation with both ARA and DHA in infant formula and raise questions regarding the safety and nutritional suitability of ARA or DHA supplementation individually.

Comparison of liver and plasma metabolic profiles in piglets of different ages as animal models for paediatric population

Liver plays an important role in drug metabolism, so studying the grade of maturation of this organ would help to develop more appropriate dosing regimens for paediatric populations. Nevertheless, considering the invasive nature of liver analyses there are obvious ethical boundaries, particularly in babies and children. In this work, we investigated the suitability of blood plasma as an alternative matrix to evaluate the biological age of liver. With this aim, we studied the correlation of plasma and liver metabolomic profiles obtained by HPLC-TOF-MS for piglets of different ages (newborns, neonates and infants). By means of Pearson correlation analysis we observed that 360 and 1784 pairs of metabolite features were significantly correlated in positive and negative ionization mode, respectively. Procrustes analysis was applied in order to assess the similarity of the clustering resulting from the data obtained from the two matrices and the two ionisation modes. The Procrustes distances were low for both ESI+ (0.3753) and ESI- (0.3673) and, hence, liver and plasma are expected to provide similar discriminatory information. Furthermore, we found that Multiblock Principal Component Analysis (MB-PCA) readily allowed us to combine the data obtained from both matrices and to better understand the clustering according to the three study groups. Considering all these results, we suggest that plasma can provide valuable insight into the maturation grade of liver in order to provide accurate dosing in paediatric population.

A maternal Western diet during gestation and lactation modifies offspring's microglial cell density and morphology in the hippocampus and prefrontal cortex in Yucatan minipigs

Changes in microglial development and morphology can be induced by inflammatory conditions and associated with eating or mood disorders, such as hyperphagia or depression. In a previous paper in the minipig model, we showed that maternal Western diet during gestation and lactation decreased hippocampus neurogenesis and food-rewarded cognitive abilities in the progeny. Whether these alterations are concomitant with a central inflammatory process in brain structures involved in learning and memory (hippocampus, HPC), cognitive (prefrontal cortex, PFC), or hedonic (orbitofrontal cortex, OFC) control of food intake is still unknown. In the present study, Yucatan minipigs (Sus scrofa) sows were exposed to two different diets during gestation and lactation (standard, SD N = 7 vs. Western diet, WD N = 9). Iba1 is a calcium-binding protein specifically expressed in microglia in the brain, which plays an important role in the regulation of the microglia function. Iba1 expression was examined by immunohistochemical analyses in the PFC, OFC and HPC of piglets. The density of microglial cells, as well as their morphology, were assessed in order to have an indirect insight of microglial cell activation state possibly in relationship with neuroinflammation. The density of Iba1-positive cells was higher in the PFC but not in the HPC of WD compared to SD piglets (p < 0.001). In the HPC, anterior and dorsolateral PFC, WD piglets had more unipolar cells, contrary to SD that had more multipolar cells (P < 0.0001). Opposite effects were observed in the OFC, with SD presenting more unipolar (P < 0.001) microglial cells compared to WD. We showed here that maternal diet during pregnancy and lactation had significant effects on morphological changes of microglial cells in the offspring, and that these effects differed between the HPC and PFC, suggesting different response mechanisms to the early nutritional environment.

Early-Life Supplementation of Bovine Milk Osteopontin Supports Neurodevelopment and Influences Exploratory Behavior

Introduction: Osteopontin (OPN) is a whey protein found at high concentration in human milk and is involved in processes such as bone cell proliferation and differentiation. Milk OPN has shown to be involved in various aspects of development, including the immune system and gut health. However, the influence of dietary bovine milk OPN inclusion on brain and cognitive development has not been studied extensively until recently. This research examines whether dietary supplementation of bovine milk OPN supports brain and cognitive development in the translational pig model. Methods: From postnatal day (PND) 2 to 34, twenty-one intact male pigs were provided ad libitum access to one of two dietary treatments, a standard soy protein isolate-based milk replacer to serve as a control diet (n = 11) and the same base diet supplemented with bovine milk OPN to serve as a test diet (n = 10). In addition to growth and health outcomes, recognition memory was tested using the novel object recognition (NOR) task from PND 28 to 32, and magnetic resonance imaging was conducted at PND 34 to evaluate brain development. Results: No dietary effects were observed for growth performance or health indices. For the behavioral analysis, pigs that received the test diet exhibited shorter (p < 0.05) latency to the first object visited compared with pigs fed the control diet. Although the control group exhibited novelty preference, there was no difference in recognition index between dietary groups. Neuroimaging outcomes revealed increased (p < 0.05) relative brain volumes of the corpus callosum, lateral ventricle, left and right internal capsule, left and right putamen-globus pallidus, and right hippocampus, and right cortex in the test group. Diffusion tensor imaging revealed higher (p < 0.05) radial diffusivity in the corpus callosum and lower (p < 0.05) fractional anisotropy in pigs provided the test diet. Conclusion: Dietary supplementation of bovine milk OPN increased the relative volume of several brain regions and altered behaviors in the NOR task. Underlying mechanisms of bovine milk OPN influencing the development of brain structures and additional behaviors warrant further investigation.

Dietary Oligofructose Alone or in Combination with 2'-Fucosyllactose Differentially Improves Recognition Memory and Hippocampal mRNA Expression

Mounting evidence suggests that dietary oligosaccharides promote brain development. This study assessed the capacity of oligofructose (OF) alone or in combination with 2'-fucosyllactose (2'-FL) to alter recognition memory, structural brain development, and hippocampal gene expression. Beginning on postnatal day (PND) 2, male pigs received one of three milk replacers formulated to contain OF, OF + 2'-FL, or no oligosaccharides (CON). Pigs were tested on the novel object recognition task using delays of 1 or 48 h at PND 22. At PND 32-33, magnetic resonance imaging (MRI) procedures were used to assess structural brain development and hippocampal tissue was collected for analysis of mRNA expression. Pigs that consumed the OF diet demonstrated increased recognition memory after a 1 h delay, whereas those consuming diets containing OF + 2'-FL displayed increased recognition memory after a 48 h delay. Pigs fed OF or OF + 2'-FL exhibited a larger relative volume of the olfactory bulbs compared with CON pigs. Provision of OF or OF + 2'-FL altered gene expression related to dopaminergic, GABAergic, cholinergic, cell adhesion, and chromatin remodeling processes. Collectively, these data indicate that dietary OF and OF + 2'-FL differentially improve cognitive performance and affect olfactory bulb structural development and hippocampal gene expression.