The role of dietary nucleotides in single-stomached animals

Non-antibiotic feed additives in diets for pigs: A review

A number of feed additives are marketed to assist in boosting the pigs' immune system, regulate gut microbiota, and reduce negative impacts of weaning and other environmental challenges. The most commonly used feed additives include acidifiers, zinc and copper, prebiotics, direct-fed microbials, yeast products, nucleotides, and plant extracts. Inclusion of pharmacological levels of zinc and copper, certain acidifiers, and several plant extracts have been reported to result in improved pig performance or improved immune function of pigs. It is also possible that use of prebiotics, direct-fed microbials, yeast, and nucleotides may have positive impacts on pig performance, but results have been less consistent and there is a need for more research in this area.

Dietary nucleotides supplementation during the suckling period improves the antioxidative ability of neonates with intrauterine growth retardation when using a pig model

The aim of the present study was to investigate the effect of dietary nucleotides supplementation on the antioxidant status of piglets affected by intrauterine growth retardation (IUGR). Fourteen pairs of normal birth weight (NBW) and IUGR piglets were fed either a control diet (CON) or a nucleotides supplementation diet (NT) from 7 d of age to 28 d postnatal. Blood, liver and jejunum samples were collected at the end of the study. The results showed that IUGR piglets had decreased (P < 0.05) concentrations of plasma total antioxidant capability (T-AOC) and total superoxide dismutase (T-SOD), gene expressions of hepatic cytoplasmic copper/zinc SOD (CuZnSOD) and PPARγ coactivator-1α (PGC-1α) and jejunal glutathione peroxidase (GP_X) and extracellular superoxide dismutase (ESOD), accordingly, there was markedly higher (P < 0.05) plasma malondialdehyde (MDA) and hepatic and jejunal mitochondria DNA content in the IUGR piglets relative to NBW piglets. Regardless of body weight, dietary NT supplementation significantly increased (P < 0.05) plasma concentrations of T-AOC, T-SOD, CuZnSOD, GP_X and the ratio of reduced glutathione to oxidized glutathione, hepatic T-SOD, GP_X and mitochondria DNA content, while hepatic MDA concentration was markedly decreased (P < 0.05) 19.1% by NT diet. Furthermore, the gene expressions of hepatic glutathione reductase, CuZnSOD, nuclear erythroid 2-related factor 2, PGC-1α and nuclear respiratory factor-1 (NRF-1) and jejunal GP_X, CuZnSOD, ESOD and NRF-1 were significantly increased (P < 0.05) by NT diet, whereas the gene expression of Kelch-like ECH-associated protein 1 were markedly decreased (P < 0.05) compared with that of piglets fed with CON diet. These results indicate that dietary NT supplementation prevents the effect of IUGR on oxidative status and mitochondria DNA damage through improving the non-enzymatic and enzymatic antioxidant capacities as well as mitochondria biogenesis of piglets.

The aim of the present study was to investigate the effect of dietary nucleotides supplementation on the antioxidant status of piglets affected by intrauterine growth retardation (IUGR).

Nucleotide-mediated SPDEF modulates TFF3-mediated wound healing and intestinal barrier function during the weaning process

Most alterations during weaning involve physiological changes in intestinal structure and function. Here, we evaluated the molecular mechanisms regulating the effects of nucleotides on weaning. Nucleotide treatment induced Trefoil factor 3 (TFF3) expression and IPEC-J2 cell growth and reduced wound width. Treatment with nucleosides and TFF3 in lipopolysaccharide-challenged IPEC-J2 cells increased intestinal transepithelial electrical resistance and decreased intestinal permeability. Additionally, nucleosides improved intestinal barrier function through induction of TFF3-mediated phosphatidylinositol 3-kinase/Akt, extracellular signal-regulated kinase 1/2, p38, and Janus kinase/signal transducer and activator of transcription signaling pathways. Among selected differentially expressed genes, SAM pointed domain containing ETS transcription factor (SPDEF) expression was elevated by nucleotides in a concentration-dependent manner. Moreover, SPDEF directly regulated TFF3 expression via binding to the promoter. In vivo, nucleotide supplementation improved growth performance, serum stress levels, and intestinal morphology. Our findings provide insights into the molecular mechanisms of intestinal development during weaning in pigs.

Comparative digestibility of energy and ileal amino acids in yeast extract and spray-dried porcine plasma fed to pigs

Two experiments were conducted to evaluate the digestible (DE) and metabolisable energy (ME), apparent (AID) and standardised ileal digestibility (SID) of amino acids (AA) in yeast extract (YE) and spray-dried porcine plasma (SDPP). In Experiment 1, 18 barrows (25.1 ± 1.2 kg body weight [BW]) were randomly allotted to three treatments with six replicates per treatment. The DE and ME of YE was 20.64 and 19.31 MJ/kg, respectively, which were not significantly different with the DE and ME of SDPP (18.74 and 18.05 MJ/kg, respectively). In Experiment 2, six barrows (20.6 ± 2.6 kg BW) fitted with ileal T-cannulas were fed three diets in a repeated 3-period Latin square design. For Met and Glu, the AID tended to be, while the SID was significantly higher (p < 0.05), in YE than in SDPP. The AID of Cys tended to be lower in YE (p = 0.07), while the SID of Phe tended to be higher in YE than in SDPP (p = 0.06). Accordingly, YE could be a potential substitute for SDPP as a superior protein ingredient in diets for pigs in terms of the available energy and AA digestibility.

Effect of yeast-derived products and distillers dried grains with solubles (DDGS) on growth performance and local innate immune response of broiler chickens challenged with Clostridium perfringens

This study evaluated the effect of yeast-derived products on growth performance, gut lesion score, intestinal population of Clostridium perfringens, and local innate immunity of broiler chickens challenged with C. perfringens. One-day-old broiler chickens were randomly assigned to eight dietary treatments providing six replicate pens of 55 birds each per treatment. Dietary treatments consisted of Control diets without and with C. perfringens challenge, and diets containing bacitracin methylene disalicylate (BMD, 55 g/tonne), nucleotides (150 g/tonne), yeast cell wall (YCW, 300 g/tonne), and a commercial product Maxi-Gen Plus (1 kg/tonne) fed to chickens challenged with C. perfringens. Diets containing 10% distillers dried grains with solubles without and with C. perfringens challenge were also used. Birds were orally challenged with C. perfringens (10(8) colony-forming units (cfu)/bird) on day 14. On day 21, intestinal samples were collected for gene expression analysis. Pathogen challenge significantly (P < 0.05) impaired feed intake, body weight gain, and feed conversion ratio (FCR) shortly after the challenge (14-21 days). Increased C. perfringens counts and intestinal lesion scores were observed for challenged birds except the BMD-containing diet. Over the entire trial (1-35 days), no difference in growth performance was observed except the BMD diet which improved FCR over the Control, challenged group. Birds receiving nucleotides showed increased expression of toll-like receptors and cytokines interleukin (IL)-4 and IL-18 compared to the Control, challenged group. Expression of macrophage mannose receptor and IL-18 was upregulated in birds receiving YCW. Increased expression of cytokines and receptors involved in innate immunity in broilers receiving nucleotides and YCW suggests the immunomodulatory properties of these products under pathogen challenge conditions.

Dietary supplementation with a nucleotide-rich yeast extract modulates gut immune response and microflora in weaned pigs in response to a sanitary challenge

An experiment was carried out to evaluate the short-term effect of supplementing a nucleotide-rich yeast extract (NRYE) on growth performance, gut structure, immunity and microflora of piglets raised under sanitary and unsanitary conditions. A total of 84, 21-day old piglets were used in this study; 42 piglets were raised in a room designated as the clean room that was washed once per week, whereas the other 42 piglets were raised in a room designated as the unclean room in which 7 kg of manure from the sow herd was spread on each pen floor on day 1 and 7 and the room was not washed throughout the experiment. The pigs were fed a corn-soybean meal-based diet without or with 0.1% NRYE. Each treatment had 7 replicate pens in each room, and each pen housed 3 pigs. Feed disappearance and BW were recorded on day 1 and 14. On day 14, one pig per pen was euthanized to collect ileum, mesenteric lymph nodes and spleen tissues, and cecum and colon digesta. Overall, NRYE supplementation did not affect growth performance in both clean and unclean conditions, improved kidney weight in both clean (P=0.0002) and unclean room (P<0.0001) and tended to improve the villus height/crypt depth ratio in the clean room (P=0.073). Supplementing NRYE was associated with upregulation of Ileal programmed cell death gene-1 (P=0.0003), interleukin (IL)-1β (P<0.0001), IL-6 (P=0.0003), IL-10 (P<0.0001) and tumor necrosis factor-α (TNF-α) (P<0.0001) in pigs raised in the unclean room. Supplementing the NRYE in pigs raised in the clean room suppressed growth of cecal Enterobacteriacea (P<0.0001) members and colonic Enterococcus spp. (P<0.019), improved proliferation of cecal Lactobacillus spp. (P<0.002) and colonic Clostridium cluster IV (P<0.011) and XVIa members (P<0.0002). Supplementing the NRYE in the unclean room improved proliferation of cecal Clostridium cluster IV (P<0.026) and suppressed proliferation of colonic Enterococcus spp. (P<0.037). In conclusion, supplementing the NRYE to piglets under unsanitary conditions improved ileal immune response by upregulating inflammatory cytokines, and positively modulated proliferation of beneficial gut bacteria and suppression of harmful ones in both clean and unclean rooms.

Nutritional support for low birth weight infants: insights from animal studies

Infants born with low birth weights (<2500 g, LBW), accounting for about 15 % of newborns, have a high risk for postnatal growth failure and developing the metabolic syndromes such as type 2 diabetes, CVD and obesity later in life. Improper nutrition provision during critical stages, such as undernutrition during the fetal period or overnutrition during the neonatal period, has been an important mediator of these metabolic diseases. Considering the specific physiological status of LBW infants, nutritional intervention and optimisation during early life merit further attention. In this review, the physiological and metabolic defects of LBW infants were summarised from a nutritional perspective. Available strategies for nutritional interventions and optimisation of LBW infants, including patterns of nutrition supply, macronutrient proportion, supplementation of amino acids and their derivatives, fatty acids, nucleotides, vitamins, minerals as well as hormone and microbiota manipulators, were reviewed with an aim to provide new insights into the advancements of formulas and human-milk fortifiers.

The Importance of Human Milk for Immunity in Preterm Infants

The immune system of preterm infants is immature, placing them at increased risk for serious immune-related complications. Human milk provides a variety of immune protective and immune maturation factors that are beneficial to the preterm infant's poorly developed immune system. The most studied immune components in human milk include antimicrobial proteins, maternal leukocytes, immunoglobulins, cytokines and chemokines, oligosaccharides, gangliosides, nucleotides, and long-chain polyunsaturated fatty acids. There is growing evidence that these components contribute to the lower incidence of immune-related conditions in the preterm infant. Therefore, provision of these components in human milk, donor milk, or formula may provide immunologic benefits.

Dietary glutamine, glutamic acid and nucleotides increase the carbon turnover (δ 13C) on the intestinal mucosa of weaned piglets

This study aimed at evaluating the influence of dietary glutamine, glutamic acid and nucleotides on duodenal and jejunal carbon turnover, and on mucosa morphometry of piglets weaned at an age of 21 days. The diets were: additive-free diet - control (C); 1% of glutamine (G); 1% of glutamic acid (GA); and 1% of nucleotides (N). In intestinal mucosa morphometry trial, 65 animals were used. At day 0 (baseline), five animals were slaughtered to determine the villus height (VH), crypt depth (CD), VH : CD ratio and villi density (VD). The remaining 60 animals were allocated into a randomized block design with 4×3 factorial arrangement (four diets: C - control, G - glutamine, GA - glutamic acid and N - nucleotides; three slaughter ages: 7, 14 and 21 days post-weaning) with five piglets slaughtered per treatment. In carbon turnover trial, 123 animals were used. At day 0 (baseline), three animals were slaughtered to quantify the δ 13C half-life (T50%) and the 99% carbon substitution (T99%) on intestinal mucosa. The remaining 120 animals were blocked by three weight categories (light, medium and heavy) and, randomly assigned to pen with the same four diets from the previous trial with one piglet slaughtered per weight category per treatment at days 1, 2, 4, 5, 7, 9, 13, 20, 27 and 49 after weaning. Morphometric analyses have yielded no consistent results regarding the action of the evaluated additives, and few reproducible age-related effects. The N diets determined lower T50% values (5.18 days) and T99% (17.21 days) than G and C diets (T50%=7.29, 7.58 days and T99%=24.22, 25.17 days, respectively) in the duodenal mucosa. In jejunum, the N, GA and G diets determined the lowest T50% means (4.9, 6.2 and 6.7 days, respectively) and T99% means (15.34, 21.10 and 21.84 days, respectively) in comparison with C diets (T50%=7.44 and T99%=24.72 days). The inclusion of the additives in the diets of piglets accelerated the carbon turnover in piglets during the post-weaning period. The stable isotopes technique (δ 13C) is an important methodology in studies of additives with trophic effects on the intestinal mucosa of the piglets.

Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance, immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide

Background

This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter (AGP) on performance, immune status and gut structure after an E. coli lipopolysaccharide (LPS) challenge. Thirty-six pigs were allotted to six treatments including: a non-challenged control (NCC); LPS-challenged control (CC); CC + AGP; CC + yeast extract; CC + enzymes; and CC + enzymes + yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal samples.

Results

Overall (d 1 to 11), compared with CC pigs, AGP attenuated the LPS-induced reduction in ADG (P = 0.004), ADFI (P = 0.03) and gain/feed ratio (P = 0.01). At 6 h post-challenge, AGP pigs had lower plasma urea N (PUN; P = 0.02) and serum TNF- α concentration (P = 0.07), and higher platelet count (P = 0.04) and serum IL-10 concentration (P = 0.02) than CC pigs. At 48 h post-challenge, AGP pigs had lower PUN (P = 0.02) than CC pigs, whereas enzymes + yeast extract interacted non-additively (P = 0.001) to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN (P = 0.02) and higher duodenal (P = 0.03), jejunal (P = 0.01) and ileal (P = 0.07) villus height than CC pigs. In addition, enzymes + yeast extract interacted additively and non-additively to reduce ileal IFN-γ (P < 0.0001) and IL-10 (P = 0.012) expression, respectively. Generally, no differences (P > 0.10) were observed between AGP and enzymes + yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ (P < 0.0001) and TNF-α (P = 0.003) in enzymes + yeast extract pigs at 96 h post-challenge.

Conclusions

The LPS challenged piglets receiving enzymes + yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance.

Dietary yeast-based nucleotides as an alternative to in-feed antibiotics in promoting growth performance and nutrient utilization in weaned pigs

Effect of dietary nucleotide supplementation without or with in-feed antibiotics on piglet performance and energy and nutrient digestibility was determined. Supplementing antibiotics without or with nucleotides (1000 ppm) increased weight gain (P < 0.05), whereas increasing nucleotide levels in antibiotic-supplemented diets linearly decreased (P < 0.05) energy and nutrient digestibility.

Dietary Nucleotides Supplementation Improves the Intestinal Development and Immune Function of Neonates with Intra-Uterine Growth Restriction in a Pig Model

The current study aimed to determine whether dietary nucleotides supplementation could improve growth performance, intestinal development and immune function of intra-uterine growth restricted (IUGR) neonate using pig as animal model. A total of 14 pairs of normal birth weight (NBW) and IUGR piglets (7 days old) were randomly assigned to receive a milk-based control diet (CON diet) or diet supplemented with nucleotides (NT diet) for a period of 21 days. Blood samples, intestinal tissues and digesta were collected at necropsy and analyzed for morphology, digestive enzyme activities, microbial populations, peripheral immune cells, expression of intestinal innate immunity and barrier-related genes and proteins. Compared with NBW piglets, IUGR piglets had significantly lower average daily dry matter intake and body weight gain (P<0.05). Moreover, IUGR markedly decreased the villous height and villi: crypt ratio in duodenum (P<0.05), as well as the maltase activity in jejunum (P<0.05). In addition, IUGR significantly decreased the serum concentrations of IgA, IL-1βand IL-10 (P<0.05), as well as the percentage of peripheral lymphocytes (P<0.05). Meanwhile, the down-regulation of innate immunity-related genes such as TOLLIP (P<0.05), TLR-9 (P = 0.08) and TLR-2 (P = 0.07) was observed in the ileum of IUGR relative to NBW piglets. Regardless of birth weight, however, feeding NT diet markedly decreased (P<0.05) feed conversion ratio, increased the villous height in duodenum (P<0.05), activities of lactase and maltase in jejunum (P<0.05), count of peripheral leukocytes (P<0.05), serum concentrations of IgA and IL-1β as well as gene expressions of TLR-9, TLR-4 and TOLLIP in ileum (P<0.05). In addition, expressions of tight junction proteins (Claudin-1 and ZO-1) in ileum were markedly increased by feeding NT diet relative to CON diet (P<0.05). These results indicated that IUGR impaired growth performance, intestinal and immune function, but dietary nucleotides supplementation improved nutrients utilization, intestinal function and immunity.

Effect of yeast-derived products and distillers dried grains with solubles (DDGS) on antibody-mediated immune response and gene expression of pattern recognition receptors and cytokines in broiler chickens immunized with T-cell dependent antigens

This study evaluated the effect of yeast-derived products on innate and antibody mediated immune response in broiler chickens following immunization with sheep red blood cells (SRBC) and bovine serum albumin (BSA). One-day-old male broiler chickens (Ross-308) were randomly assigned to 6 dietary treatments of 9 replicate cages of 5 birds each per treatment. Dietary treatments consisted of a Control diet without antibiotic, and diets containing 11 mg/kg of virginiamycin, 0.25% of yeast cell wall (YCW), 0.2% of a commercial product Maxi-Gen Plus containing processed yeast and nucleotides, 0.05% of nucleotides, or a diet containing 10% of DDGS. On days 21 and 28 post-hatching, 5 birds per treatment were immunized intramuscularly with both SRBC and BSA. One week after each immunization, blood samples were collected. Serum samples were analyzed by hemagglutination test for antibody response to SRBC, and by ELISA for serum IgM and IgG response to BSA. On d 35, 5 birds per treatment were euthanized and the tissue samples from the cecal tonsils were collected to assess the gene expression of toll-like receptors TLR2b, TLR4, and TLR21, monocyte mannose receptor (MMR), and cytokines IL-10, IL-13, IL-4, IL-12p35, and IFN-γ. The results for gene expression analysis demonstrated that the diet supplemented with YCW increased the expression of TLR2b and T-helper type 2 cytokines IL-10, IL-4, and IL-13 relative to the Control; and the expression of TLR4 and IL-13 was upregulated in the nucleotide-containing diet. However, the diets containing antibiotics or Maxi-Gen Plus downregulated the expression of IFN-γ compared to the control. The primary antibody response to SRBC was not affected by diets. However, the diet containing YCW increased the secondary antibody response to SRBC compared to the antibiotic treatment. Neither primary nor secondary IgG and IgM response against BSA were affected by diets. In conclusion, supplementation of the diet with YCW stimulated Th2 cell-mediated immune response indicating the immunomodulatory activities of these products following immunization with non-inflammatory antigens.

Dose-response effects of in-feed antibiotics on growth performance and nutrient utilization in weaned pigs fed diets supplemented with yeast-based nucleotides

Dietary nucleotides are bioactive compounds with the potential to mitigate weaning-associated challenges in piglets. An experiment was conducted to determine the interaction effect of antimicrobial growth promoters (AGP) and a nucleotide-rich yeast extract (NRYE) on growth performance and apparent total tract digestibility (ATTD) of dry matter (DM), crude protein (CP) and gross energy (GE), and to establish whether NRYE supplementation may completely or partially replace AGP in diets for weaned pigs. In phase 1 and 2, corn, wheat, canola meal and soybean meal based diets, which were formulated to contain 0.0 or 0.1% NRYE with 0, 25, 50, 75 or 100% of the recommended AGP dosage, were fed to 108 twenty-one day old piglets (initial body weight 7.11 ± 0.9 kg; mean ± SD) from d 1 to 14 and 15 to 28, respectively. Overall, increasing AGP level in NRYE supplemented diets linearly decreased average daily gain (ADG) (P = 0.002) and gain-to-feed ratio (G:F) (P = 0.007); and quadratically decreased ATTD of DM (P = 0.001), CP (P = 0.003) and G:F (P = 0.017) during phase 2. Compared with control and pigs fed NRYE with 100% of recommended AGP dosage, pigs fed 0.1% NRYE without AGP had greater (P < 0.05) ADG and G:F in phase 2 and overall. In conclusion, supplementing 0.1% NRYE improved growth performance of pigs but this beneficial effect was reduced by increasing dietary AGP dosage.

Alternatives to antibiotics in animal agriculture: an ecoimmunological view

Ecological immunology (or ecoimmunology) is a new discipline in animal health and immunology that extends immunologists’ views into a natural context where animals and humans have co-evolved. Antibiotic resistance and tolerance (ART) in bacteria are manifested in antibiosis-surviving subsets of resisters and persisters. ART has emerged though natural evolutionary consequences enriched by human nosocomial and agricultural practices, in particular, wide use of antibiotics that overwhelms other ecological and immunological interactions. Most previous reviews of antibiotic resistance focus on resisters but overlook persisters, although both are fundamental to bacteria survival through antibiosis. Here, we discuss resisters and persisters together to contrast the distinct ecological responses of persisters during antibiotic stress and propose different regimens to eradicate persisters. Our intention is not only to provide an ecoimmunological interpretation, but also to use an ecoimmunological system to categorize available alternatives and promote the discovery of prospective approaches to relieve ART problems within the general scope of improving animal health. Thus, we will categorize available alternatives to antibiotics and envision applications of ecoimmunological tenets to promote related studies in animal production.

Nucleotide enrichment of live feed: a promising protocol for rearing of Atlantic cod Gadus morhua larvae

We investigated the effect of two commercial nucleotide products (NT1 and NT2), administered through live feed, on growth and stress tolerance of Atlantic cod larvae. Expression of genes related to muscle growth (igf-1, igf1r, igf-2, fst, fgf6, myod, and myhc) and nucleotide metabolism (uox, hprt, ndk, and uck) was evaluated during larval development. In addition, the expression of genes related to stress (hif-1α, hif-2α, hif-3α, and mb) was studied after an air exposure stress test. The enrichment of rotifers with nucleotides did not reveal any difference in nucleotide profiles, the exception being the RNA level of the NT1-enriched group that was significantly higher than the unenriched rotifer. Unenriched Artemia showed poor nucleotide profiles compared to enriched Artemia since 5' UMP, 5' GMP, and 5' AMP were observed only in the nucleotide groups. At 38 days post-hatch (dph), NT1 group had significantly higher dry weight (3.1 ± 0.1 mg) than the control (CON; 2.3 ± 0.1 mg). The treatments did not produce any significant differences in the expression of the key myogenic genes. Among the genes associated with nucleotide metabolism, ndk was down-regulated in NT1 at 38 dph. In the air exposure test, survival was significantly higher in the CON (77 ± 6 %) than in NT1 (48 ± 3 %) and NT2 (50 ± 3 %). After air exposure, mb was expressed at lower levels in NT2 group, hif-2α was induced in NT1 group, and hif-3α was upregulated in all groups. Our findings indicate that the improvement in the nucleotide profile of Artemia upon nucleotide enrichment could eventuate in the rapid growth of larvae.

The effects of pure nucleotides on performance, humoral immunity, gut structure and numbers of intestinal bacteria of newly weaned pigs

Weaning is often stressful for piglets and accompanied by morphological, histological, microbial, and immunological changes along the digestive tract. Dietary nucleotides are bioactive compounds which have the potential to diminish weaning-associated challenges. The experiment was carried out with 5 litters each of 7 pigs (mixed sex), weaned at 20 d of age. One baseline pig per litter was slaughtered at d 0. The remaining 30 pigs were housed individually and randomly allocated to 2 dietary treatments: the control diet or the control diet supplemented with a mixture of nucleotides. Measurements of growth performance traits included ADFI, ADG, G:F, and BW. At d 17, fresh fecal samples were taken to determine bacterial numbers. On d 19 and 20, pigs were slaughtered and blood samples were analyzed for plasma immunoglobulins and intestinal samples were assessed for morphological traits. Digesta from the jejunum and cecum were collected for analysis of the microbiome. The ADFI was greater in the nucleotide treatment compared with the control treatment (P < 0.05), but ADG, G:F, and BW did not differ between treatments. Plasma IgA concentrations increased with age and were greater in the nucleotide (P < 0.05) compared with the control group. There were no treatment differences in plasma IgG and IgM, gut morphology, or intestinal and fecal bacterial counts. Supplemental nucleotides may increase ADFI but without having any impact on growth performance of the pigs. Greater plasma IgA concentrations indicate that adding nucleotides in the weaning diet supported humoral immunity. However, there was no effect of dietary nucleotide supplementation on the composition of the bacterial community in parts of the small and large intestine. Further research is warranted before the use of nucleotide as a feed additive in pig diet can be recommended.

Short-term effect of dietary yeast nucleotide supplementation on small intestinal enzyme activities, bacterial populations and metabolites and ileal nutrient digestibilities in newly weaned pigs

In previous studies, dietary nucleotides have been shown to improve performance in single-stomached animals by promoting the renewal of small intestine epithelial cells and by influencing the activity and composition of the microbial community in the digestive tract. The present experiment was carried out with 12 barrows weaned at the age of 18 days and fitted with a simple T-cannula at the distal ileum. To determine short-term effects of dietary yeast nucleotides, the piglets received a grain-soybean meal-based basal diet with or without supplementation of 1 g/kg of a dried yeast product containing free nucleotides. Dietary supplementation with yeast did not affect bacterial numbers in the ileum as well as ileal concentrations of individual short-chain fatty acids (SCFA), total SCFA and total lactic acid (p > 0.05). Moreover, there was no effect of supplemental yeast nucleotides on ileal α-amylase, leucine amino peptidase, maltase and lactase activities (p > 0.05), as well as on ileal dry matter, crude protein and crude fibre digestibilities (p > 0.05). In conclusion, short-term supplementation with dietary yeast nucleotides did not affect microbial metabolite concentrations, bacterial numbers and enzyme activities in the ileal digesta as well as ileal nutrient digestibilities of newly weaned pigs.