Birth weight has no influence on the morphology, digestive capacity and motility of the small intestine in suckling pigs

Effects of Different Weaning Weight on Growth Performance, Serum Biochemical Indices and Intestinal Health of Piglets

A 3-week feeding experiment was conducted to explore the effects of different weaning weights on growth performance, apparent nutrient digestibility, serum biochemical indices, and intestinal health of piglets weaned at 21 days of age. Forty healthy (Landrace × Yorkshire) binary crossbred pigs with the same birth age and weaned at Day 21 were assigned to two treatments including L (5.0-5.5 kg) and H (6.5-7.0 kg), each with five replicates and four piglets per replicate. The two groups were fed the same diet. Data revealed that the average daily gain of high-weight piglets after weaning at 21 days was significantly higher than that of low-weight weaned piglets (p < 0.05); The crude fat (EE) and crude protein (CP) of H-piglets was significantly higher than that of l-piglets; There was no significant difference in the contents of total protein (TP), alkaline phosphatase (ALP), glutamic pyruvic transaminase (ALT), cholesterol (CHO), glucose (GLU), immunoglobulin M (IgM), triglyceride (TG), albumin (ALB), glutamic oxaloacetic transaminase (AST) and UREA between H-piglets and l-piglets after weaning at 21 days (p > 0.05). There was no significant difference in the villus height (VH), crypt depth (CD) and VH:CD ratio (VRC), and no significant difference in the relative abundance of intestinal flora at phyla and genus level (p > 0.05). In summary, the growth performance of piglets after weaning at 21 days is related to their weaning weight.

Effect of small peptide chelated iron on growth performance, immunity and intestinal health in weaned pigs

BACKGROUND

Small peptide chelated iron (SPCI), a novel iron supplementation in pig diets, owns growth-enhancing characteristics. Although a number of researches have been performed, there is no clear-cut evidence to show the exact relationship between the dose and effects of small peptide chelated minerals. Therefore, we investigated the effect of dietary supplementation of SPCI at different doses in the growth performance, immunity, and intestinal health in weaned pigs.

METHODS

Thirty weaned pigs were randomly assigned into five groups and feed with basal diet or the basal diet containing 50, 75, 100, or 125 mg/kg Fe as SPCI diets. The experiment lasted for 21 d and on day 22, blood samples were collected 1 h later. The tissue and intestinal mucosa samples were collected following.

RESULTS

Our results showed that the feed to gain ratio (F:G) decreased with different levels of SPCI addition (P < 0.05). The average daily gain (ADG) (P < 0.05) and digestibility of crude protein (P < 0.01) decreased with 125 mg/kg SPCI addition. With dietary different levels of SPCI addition, the serum concentrations of ferritin (quadratic, P < 0.001), transferrin (quadratic, P < 0.001), iron content in liver (quadratic, P < 0.05), gallbladder (quadratic, P < 0.01) and fecal (quadratic, P < 0.01) increased quadraticly. While the iron content in tibia (P < 0.01) increased by 100 mg/kg SPCI supplementation. Dietary 75 mg/kg SPCI addition increased the serum insulin-like growth factor I (IGF-I) (P < 0.01) and SPCI (75 ~ 100 mg/kg) addition also increased the serum content of IgA (P < 0.01). The serum concentrations of IgG (quadratic, P < 0.05) and IgM (quadratic, P < 0.01) increased quadraticly by different levels of SPCI supplementation. Moreover, different levels of SPCI supplementation decreased the serum concentration of D-lactic acid (P < 0.01). The serum glutathione peroxidase (GSH-Px) (P < 0.01) elevated but the malondialdehyde (MDA) (P < 0.05) decreased by 100 mg/kg SPCI addition. Interestingly, SPCI supplementation at 75 ~ 100 mg/kg improved the intestinal morphology and barrier function, as suggested by enhanced villus height (P < 0.01) and villus height/crypt depth (V/C) (P < 0.01) in duodenum, as well as jejunum epithelium tight-junction protein ZO-1 (P < 0.01). Moreover, SPCI supplementation at 75 ~ 100 mg/kg increased the activity of duodenal lactase (P < 0.01), jejunal sucrase (P < 0.01) and ileal maltase (P < 0.01). Importantly, the expression levels of divalent metal transporter-1(DMT1) decreased with different levels of SPCI addition (P < 0.01). In addition, dietary SPCI supplementation at 75 mg/kg elevated the expression levels of critical functional genes such as peptide transporter-1(PePT1) (P = 0.06) and zinc transporter 1 (ZnT1) (P < 0.01) in ileum. The expression levels of sodium/glucose co-transporter-1 (SGLT1) in ileum (quadratic, P < 0.05) increased quadraticly by different levels of SPCI addition and amino acid transporter-1 (CAT1) in jejunum(P < 0.05) also increased by 100 mg/kg SPCI addition.

CONCLUSIONS

Dietary SPCI supplementation at 75 ~ 100 mg/kg improved growth performance by elevated immunity and intestinal health.

Developmental Profiling of Dietary Carbohydrate Digestion in Piglets

Carbohydrates are the main source of energy in the diet, accounting for the largest proportion in the diets of humans and monogastric animals. Although recent progress has been made in the study of intestinal carbohydrate digestion in piglets, there is a lack of comprehensive study on the dynamic changes in intestinal carbohydrate digestion with age in the early growth stage of piglets. To fill in this gap of knowledge, we collected samples of the small intestine, pancreatic tissues, and colonic digesta from 42 piglets during newborn [day (d) 0], lactation (d 7, 14), weaning (d 21), and nursery (d 28, 35, and 42) stages. Intestinal and pancreatic tissues and colonic digesta were collected at necropsy and analyzed for morphology, digestive enzyme activities, short-chain fatty acids (SCFA), and microbial abundance. Villus height reached a maximum at 1 week (d 7) in the duodenum and jejunum (P <0.01), and a higher ratio of villus height to crypt depth and lactase activity were observed on d 0 and 7 (P < 0.001) compared to other ages. However, the sucrase and maltase activities were increased with piglets' age. Similar activities of sucrase and maltase were found in the small intestine. In addition, amylase, lipase, and protease activities were assayed in the pancreas. The activity of amylase increased with age, while lipase and protease decreased gradually from birth to weaning (d 21, 28) and then increased after weaning (d 35, 42). Compared with d 0, d 42 increased the abundance of Firmicutes and Bacteroidetes with a higher concentration of total SCFA (P < 0.001) and decreased the abundance of Proteobacteria, but weaning (d 21, 28) increased the abundance of Proteobacteria in the colon. These results indicate that with the increase in piglet age, the carbohydrate digestive function gradually increased, but weaning hindered the development of intestinal function. These results provide us with new insights into the healthy development of piglets' intestines, which may help us to better regulate the physiological health of piglets in the future.

Effects of oral glutamine supplementation on jejunal morphology, development, and amino acid profiles in male low birth weight suckling piglets

Background

It has been shown that small intestine development in low birth weight (LBW) piglets is impaired. Glutamine (Gln) has been reported to improve piglet health and intestinal function in weaned piglets, but data is scarce in suckling piglets. This study was conducted to investigate the effects of oral Gln supplementation compared to Alanine (Ala) on jejunal development and function in 5 and 12 d old male LBW and normal birth weight (NBW) suckling piglets.

Results

Gln had no effect on the jejunal morphology, development, tissue and digesta amino acid profiles and mRNA abundance of genes involved in amino acid transport, metabolism, glutathione synthesis in LBW piglets when compared to Ala supplementation and birth weight controls at 5 and 12 d. Only the concentration of Gln in jejunal tissue was higher in NBW piglets supplemented with Gln compared to Ala at 5 d (P < 0.05). A comparison of the birth weight groups showed no differences between LBW and NBW piglets at 5 and 12 d in any parameter. Jejunal crypt depth, villus height / width, tunica muscularis thickness, number of goblet and IgA positive cells, the ratio of jejunal RNA to DNA and the concentration of DNA, protein and RNA changed (P < 0.05) from 5 compared to 12 d. The concentrations of several free, and protein bound amino acids as well as amino metabolites differed between age groups in jejunal tissue but the digesta concentrations were affected to a lesser extent.

Conclusions

Oral Gln supplementation to suckling male piglets over the first 12 d of life was not associated with changes in jejunal parameters measured in this study. The absence of effects may indicate that Gln is absorbed as well as metabolized in the upper intestinal tract and thus could benefit intestinal development at a more proximal location.

The Effect of Feeding Liquid or Dry Creep Feed on Growth Performance, Feed Disappearance, Enzyme Activity and Number of Eaters in Suckling Piglets

Simple Summary

The transition from sow’s milk to a vegetable-based diet around weaning is one of the most critical periods in a pig’s life, due to the strong association between undigested nutrients and post weaning diarrhoea. For practical and economic reasons, piglets are weaned before their gastro-intestinal tract has fully developed. Early provision of creep feed could be one way of promoting gut maturation and may thus be used as a preventive tool for post weaning diarrhoea instead of medicinal zinc oxide. Increasing the activity of enzymes involved in the digestive processes might enhance gut maturation, thereby preparing the piglet for weaning. Therefore, the objective of this study was to investigate the effect of dry and liquid creep feed on growth performance, enzyme activity and the number of pigs actually consuming creep feed. In conclusion, in this on-farm setup, the pigs fed the dry diet displayed a greater enzyme activity in the proximal part of the small intestine and a higher weight gain, suggesting more mucosal maturation and adaptation to a vegetable-based diet.

Abstract

The aim of this study was to investigate the effect of two dietary treatments (liquid creep feed (LCF) and dry creep feed (DCF)) offered during the suckling period on feed disappearance, number of eaters, and intestinal enzymatic development at weaning in an on-farm study with 347 piglets. Piglets were allocated to either the DCF or LCF treatment from day 10 to day 24 postpartum for 9 h a day. Red ferric oxide (1%) was added to the diet to categorize piglets into eating categories (good eaters, moderate eaters, or non-eaters) via faecal swabs. At weaning, 40 piglets were sampled for intestinal enzymatic development. The LCF treatment increased the dry matter disappearance from day 10–18 (p < 0.001). The percentage of good eaters, moderate eaters and non-eaters did not differ between treatments (p > 0.05). The DCF pigs displayed greater average daily gain (ADG) pre-weaning (p = 0.024), and a greater body weight (BW) at day 61 (p < 0.001). The activity of lactase, maltase and sucrase in the proximal part of the small intestine were greatest (p < 0.001) in the DCF pigs.

Effects of iron, vitamin A, and the interaction between the two nutrients on intestinal development and cell differentiation in piglets

This study aimed to investigate the effects of iron, vitamin A (VA) and their interaction on intestinal development and differentiation of cells in suckling piglets. Therefore, 32 Duroc × Landrace × Yorkshire 0-d-old newborn boars with similar body weights were randomly divided into four groups, with eight replicates in each group and one pig in each replicate. All the piglets were breastfed. In addition, the piglets were given normal saline (CON group) or ferrous sulfate (OAFe group) or VA (VA group) or ferrous sulfate and VA (OAFe + VA group) on the 2nd, 7th, 12th, and 17th day, respectively. The piglets were then slaughtered on the 21st day, and intestinal samples were collected. The results showed that: 1) iron (P < 0.001) significantly increased the length, weight, relative weight, and the length to weight ratio of the small intestine. On the other hand, VA had a significant effect on the weight to length ratio (P = 0.015) and relative weight (P < 0.001) of the small intestine; 2) with regard to intestinal morphology, supplementation with iron (P <0.05) had obvious effects on the villus height (VH), crypt depth (CD), villus width (VW), and surface area. Additionally, both VA and interaction of VA and iron increased the VH (P < 0.05) and surface area (P = 0.001). The results also showed that iron (P < 0.01) increased the number of crypt goblet cells, Ki67-positive cells, and endocrine cells. Moreover, both VA and the interaction between VA and iron increased the number of endocrine cells in the villi (P = 0.05); 3) With regard to the mRNA expression levels of stem cell differentiation marker genes, iron (P < 0.05) decreased the expression of trophinin 2 (Trop2), leucine-rich repeat containing G protein-coupled receptor 5 positive (Lgr5+), male-specific lethal 1(Msl1), BMI 1 proto-oncogene, polycomb ring finger (Bmi1), and achaete-scute family bHLH transcription factor 2 (Ascl2). On the other hand, VA increased the expression of Ascl2 (P = 0.001) although the interaction of VA and iron (P < 0.05) had an effect on the expression of secreted phosphoprotein 1 (Spp1) and Bmi1. In addition, VA decreased the gene or mRNA expression of aconitase 1 (Aco1; P < 0.001), transferrin receptor (TFRC; P = 0.001), and solute carrier family 11 member 2 (DMT1; P = 0.003) in the Iron Reactive Element/Iron Regulatory Protein (IRE/IRP) signaling pathway although iron and the interaction of VA and iron had no effect on the genes' expression. The results therefore showed that VA, iron, and their interaction can promote intestinal development and epithelial cell differentiation in piglets.

Changes in Faecal Microbiota Profiles Associated With Performance and Birthweight of Piglets

The gastrointestinal tract microbiota interacts with the host to modulate metabolic phenotype. This interaction could provide insights into why some low birthweight pigs can exhibit compensatory growth whilst others remain stunted. This study aimed to identify microbiota markers associated with birthweight [low birthweight (n = 13) or normal birthweight pigs (n = 13)] and performance ["good" or "poor" average daily gain (ADG) class]. Furthermore, the study determined whether the taxonomic markers were longitudinal, or time point specific in their ability to identify low birthweight pigs who could exhibit compensatory growth. Faecal samples were collected and liveweight recorded at 10 different time points from birth to 56 days of age. No consistent associations between birthweight, performance and gut microbiota were found across all time points. However, there was a significant (P < 0.05) effect of birthweight on microbiota richness at 21, 27, 32 and 56 days of age. Significant differences (P < 0.05) in genera abundance according to birthweight and performance were also identified. Low birthweight pigs had a significantly (P < 0.05) lower abundance of Ruminococcaceae UCG-005, but a significantly (P < 0.05) higher abundance of Ruminococcaceae UCG-014 on days 21 and 32, respectively. Piglets classified as having a "good" ADG class had a significantly (P < 0.05) higher abundance of Lactobacillus, unclassified Prevotellaceae and Ruminococcaceae UCG-005 on days 4, 8 and 14, respectively. Furthermore, Ruminococcaceae UCG-005 was significantly more abundant at 14 days of age in normal birthweight pigs with a "good" ADG class compared to those classified as "poor." The results of this study indicate that there are time point-specific differences in the microbiota associated with birthweight and performance, corresponding to the period in which solid feed intake first occurs. Identifying early-life microbiota markers associated with performance emphasises the importance of the neonatal phase when considering intervention strategies aimed at promoting performance.

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

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

Dietary vitamin A affects growth performance, intestinal development, and functions in weaned piglets by affecting intestinal stem cells

Vitamin A (VA) is an important nutrient for weaning piglets. It plays a significant role in the normal formation, development, and maintenance of epithelial cells. Previous studies have shown that VA supplements could improve the host's intestinal barrier function. Therefore, we hypothesized that VA supplements can affect intestinal function in weaned piglets by regulating intestinal stem cells. Thirty-two 21-d-old weaned [(Yorkshire × Landrace) × Duroc] piglets with an average weight of 8.34 ± 0.13 kg were randomly divided into 4 treatment groups, with 1) 2 mg/kg (control), 2) 4 mg/kg, 3) 8 mg/kg, and 4) 16 mg/kg doses of VA, respectively. The experiment lasted for 14 d. Weaned piglets were given ad libitum access to food and water during the test. The ADG (linear, P = 0.020) and G:F (linear, P = 0.005) of the piglets were found to increase significantly from days 8 to 14. The Lgr5+ gene expression (P = 0.012) in the jejunum mucosa of the 16 mg/kg VA group was increased. The jejunum villus height (P = 0.027) and villi surface area (P = 0.035) were significantly increased in the 4 mg/kg VA treatment group. The crypt depth increased significantly in the 4 and 8 mg/kg VA treatment groups (quadratic, P = 0.043), and the ratios of villus height to crypt depth significantly increased in the 16 mg/kg VA group (quadratic, P = 0.015). The maltase (P = 0.032), sucrose (P = 0.041), and alkaline phosphatase activity (linear, P = 0.024) were significantly increased when further supplemented with 4 mg/kg VA. Slc2a2 mRNA abundance was significantly increased in the 2 mg/kg VA group (linear, P = 0.024). Moreover, the budding rates, buddings number per organoid, and Chromogranin A and Muc2 expression of piglet intestinal organoids were significantly reduced (P < 0.05) by VA and its metabolites (retinoic acid). Compared with the control group, the expression of Spp1 and Trop2 increased. These results indicated that VA may increase the stemness of intestinal stem cell in vitro. This study suggested that VA could affect growth performance and intestinal function by regulating intestinal stem cells in the jejunum of weaned piglets.

A comparison of the anatomical and gastrointestinal functional development between gilt and sow progeny around birth and weaning1

Gilt progeny (GP) often have restricted growth performance and health status in comparison to sow progeny (SP) from birth, with the underlying mechanisms responsible for this yet to be fully understood. The present study aimed to compare differences in growth and development between GP and SP in the first 24 h after birth and in the periweaning period. Two cohorts of pigs including 36 GP and 37 SP were euthanized at 1 of 4 time points: a birth cohort (at birth before suckling, 0 h; and 24 h after birth, 24 h; n = 33) and a weaning cohort (at approximately 29 d of age; "pre-weaning," PrW; and 24 h after weaning; "post-weaning," PoW; n = 40). Pigs were individually weighed at 0 h, 24 h, PrW, and PoW up until the point of euthanasia, at which time the weights of selected tissues and organs were recorded and analyzed relative to BW. The length of the small intestine (SI), femur, and body were also measured, and a serum sample was collected and analyzed for IgG concentration. Samples of jejunal and ileal mucosa were collected and analyzed for total protein and specific activity of lactase. Euthanized GP were lighter (P < 0.01) than SP at all time points. At all time points, the ratios of quadriceps weight to femur length, BW to body length, spleen to BW (all P < 0.05), and SI weight to length (P < 0.10) were lower in GP than in SP. There was no difference (P ≥ 0.05) in stomach or heart to BW ratios between GP and SP in either cohort. The brain to liver weight ratio was greater (P = 0.044) in GP than in SP in the birth cohort, and the brain to BW ratio was greater (P < 0.01) in GP in both the birth and weaning cohorts. The liver to BW ratio was similar (P = 0.35) at birth but greater (P = 0.014) in GP around weaning. Total mucosal protein content in the jejunum and ileum was lower (P = 0.007) in GP at 24 h compared with SP, and specific activity of lactase was greater (P = 0.022) in GP in the birth cohort, whereas there were no differences in the weaning cohort (P ≥ 0.10). Gilt progeny had lower (P < 0.001) serum IgG concentration compared with SP at 24 h, but there was no difference (P ≥ 0.10) in the weaning cohort. Collectively, these findings suggest that the early development of GP may be delayed compared with SP and that a number of the anatomical differences between GP and SP that exist after birth are also present at weaning.

Sows in mid parity are best foster mothers for the pre- and post-weaning performance of both light and heavy piglets1

To improve the performance of lightweight piglets during suckling, producers are advised to create uniform litters using young sows. However, fostering piglets to primiparous sows may confer penalties due to their lower milk yield and milk immunoglobulin concentrations compared with multiparous sows. The objective was to determine the effect of foster sow parity (primiparous (F), second (S), and mid parity (M: parity 3 to 5)) on the performance from birth to day 68 of piglets born light (L: ≤1.25 kg) or heavy (H: 1.50-2.00 kg) and on creep feed consumption. Piglets (n = 507) considered L or H were cross-fostered, creating litters of 13 similar-sized piglets/litter and were randomly fostered to one of the foster parities. All litters were offered creep feed with a green dye to discern between consumers and nonconsumers, and the medication administered was recorded. Medication administrated pre- and postweaning did not differ (P > 0.05) across the different experimental groups. A significantly (P ≤ 0.025) lower number of H piglets were removed as a result of preweaning weight loss from F and S, rather than M litters. The interaction between birth weight and foster parity only affected piglet BW at day 10 (P = 0.020); foster parity did not influence BW of L piglets, but influenced that of H piglets. H piglets in F and M litters (3.82 and 3.80 kg) were significantly lighter (P ≤ 0.013) than H piglets in S litters (4.15 kg). As expected, L piglets performed worse pre- and postweaning than H piglets; they were 4.50 kg lighter at day 68. Foster parity significantly affected BW: F piglets were weaned lighter (P = 0.004) than S and M piglets (7.52 vs. 8.02 kg). Postweaning (day 68) however, F piglets achieved similar BW as S piglets (29.7 vs. 29.9 kg), whereas M piglets performed best (31.2 kg, P ≤ 0.079). Significantly fewer (almost none) of the L than the H piglets consumed creep feed (P < 0.001); significantly (P = 0.007) more F and M piglets were considered consumers than S piglets. The results suggest that irrespectively of birth weight, piglets tend to perform better when in M litters, being weaned heavy and having a high creep feed intake; however, more piglets are removed from such litters preweaning. Although S litters were weaned heavy, they were unable to maintain this BW advantage postweaning, due to their low creep feed intake and F litters remained small throughout. Long-term performance monitoring to slaughter is recommended.

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

Birthweight and age can play a role in adaptational changes in plasma levels of glucose and amino acids by regulating the intestinal expression of specific nutrients transporters in piglets. The aim of the present study was to compare hematological features, circulating levels of glucose and amino acids, and small intestinal gene expression for transporters for glucose (SGLT1, GLUT2), amino acids (LAT2, b^0,+AT) and peptides (PepT1) between low birthweight (LBW) and normal birthweight (NBW) piglets at birth prior to suckling and day 7 after birth. A secondary aim was to evaluate correlations between circulating levels of glucose or amino acids and their transporters. There were significant age-dependent changes in the immune cell repertoire in the circulating blood (P<0.004). Blood glucose levels were lower in LBW piglets than in NBW piglets (P<0.05); in both birthweight groups, blood glucose increased with age. Plasma concentrations of histidine, isoleucine, proline and tryptophan showed significant changes with age (P<0.003). With regard to mRNA levels for the nutrient transporters, there were no differences between the two birthweight groups or between the two age groups. At day 7 postpartum, intestinal expression of SGLT1 or GLUT2 mRNA did not correlate with blood glucose level. Expression of LAT2 mRNA in the ileum correlated positively with plasma level of methionine (r=0.92, P<0.001). This is the first detailed analysis of hematological features, plasma glucose and amino acid levels, and nutrient transporter expression in LBW and NBW piglets during the early suckling period.

Effects of galacto-oligosaccharides on growth and gut function of newborn suckling piglets

Background

Most research on galacto-oligosaccharides (GOS) has mainly focused on their prebiotic effects on the hindgut, but their beneficial effects on the small intestine (SI) have received little attention. Since jejunum is the important place to digest and absorb nutrients efficiently, optimal maturation of the jejunum is necessary for maintaining the high growth rate in the neonate. Therefore, this study investigates the effect of the early intervention with GOS on the intestinal development of the jejunum.

Methods

A total of 6 litters of neonatal piglets (10 piglets per litter; Duroc × Landrace × Large White) with an average birth weight of 1.55 ± 0.05 kg received 1 of 2 treatments based on their assignment to either the control (CON) group or the GOS (GOS) group in each litter. Piglets in the GOS group were orally administrated 10 mL of a GOS solution (reaching 1 g GOS/kg body weight) per day from the age of 1 to 7 d; the piglets in the CON group were treated with the same dose of physiological saline. All piglets were weaned on d 21. On d 8 and 21 of the experimental trial, 1 pig per group from each of the 6 litters was euthanized.

Results

The early intervention with GOS increased the average daily gains in the third week (P < 0.05). Decreased crypt depth was also observed in the jejunum of the piglets on d 21 (P < 0.05). The early intervention with GOS increased the jejunal lactase activity on d 8, maltase activity and sucrase activity on d 21 (P < 0.05). In addition, the early intervention with GOS also facilitated the mRNA expression of Sodium glucose co-transporter 1 (SGLT1) on d 8 and the mRNA expression of Glucose transporter type 2 (GLUT2) on d 21 (P < 0.05). It was further determined that GOS up-regulated the mRNA expression of preproglucagon (GCG), insulin-like growth factor 1 (IGF-1), insulin-like growth factor 1 receptor (IGF-1R) and epidermal growth factor (EGF). GOS also up-regulated the protein expression of glucagon-like peptide-2 (GLP-2) and EGF in the jejunum of the piglets. Furthermore, it was also found that GOS enhanced the protein expression of ZO-1 and occludin on d 8 (P < 0.05), as well as increased the mRNA expression of TGF-β and decrease the mRNA expression of IL-12 (P < 0.05).

Conclusions

These results indicate that GOS have a positive effect on piglet growth performance in addition to decreasing the crypt depth and enhancing functional development in jejunum of suckling piglets.

Electronic supplementary material

The online version of this article (10.1186/s40104-018-0290-9) contains supplementary material, which is available to authorized users.

Artificial rearing influences the morphology, permeability and redox state of the gastrointestinal tract of low and normal birth weight piglets

BACKGROUND

In this study the physiological implications of artificial rearing were investigated. Low (LBW) and normal birth weight (NBW) piglets were compared as they might react differently to stressors caused by artificial rearing. In total, 42 pairs of LBW and NBW piglets from 16 litters suckled the sow until d19 of age or were artificially reared starting at d3 until d19 of age. Blood and tissue samples that were collected after euthanasia at 0, 3, 5, 8 and 19 d of age. Histology, ELISA, and Ussing chamber analysis were used to study proximal and distal small intestine histo-morphology, proliferation, apoptosis, tight junction protein expression, and permeability. Furthermore, small intestine, liver and systemic redox parameters (GSH, GSSG, GSH-Px and MDA) were investigated using HPLC.

RESULTS

LBW and NBW artificially reared piglets weighed respectively 40 and 33% more than LBW and NBW sow-reared piglets at d19 (P < 0.01). Transferring piglets to a nursery at d3 resulted in villus atrophy, increased intestinal FD-4 and HRP permeability and elevated GSSG/GSH ratio in the distal small intestine at d5 (P < 0.05). GSH concentrations in the proximal small intestine remained stable, while they decreased in the liver (P < 0.05). From d5 until d19, villus width and crypt depth increased, whereas PCNA, caspase-3, occludin and claudin-3 protein expressions were reduced. GSH, GSSG and permeability recovered in artificially reared piglets (P < 0.05).

CONCLUSION

The results suggest that artificial rearing altered the morphology, permeability and redox state without compromising piglet performance. The observed effects were not depending on birth weight.