Novel fermentable fiber made from milk sugar
aids piglet transition into nursery
GOS supplementation, along with creep feeding, positively impacts beneficial microbes
By Timothy E. Boston, Feng Wang, Xi Lin, Sung Woo Kim, Vivek Fellner, Mark F. Scott, Amanda L. Ziegler, Laurianne Van Landeghem, Anthony T. Blikslager and Jack Odle
Nursery pigs face high morbidity and mortality due to reduced feed intake, dietary shifts and stress at weaning. Historically, dietary antibiotics were used to reduce pathogenic bacteria, but concerns about antimicrobial resistance have led to alternative approaches. Creep feeding and prebiotic fiber are now being explored to aid weaning transition while reducing antibiotic reliance.
Creep feeding to supplement lactation, particularly with liquid and gruel creep diets, can increase intake and support higher weaning weights. A wide array of fermentable prebiotics are also being added to nursery diets to promote beneficial gut bacteria. Although prebiotics are not digested but by the piglet, they can be fermented by gut bacteria, potentially boosting short-chain fatty acids (SCFA) production and enhancing gut health in early life.
Novel elements of our research first include the use of an automated gruel creep feeder manufactured by Baker (Mini Transition Feeder) which precisely mixes water with creep feed to promote greater intake. Secondly, we examine a new feed-grade prebiotic (galactooligosaccharide, GOS) manufactured by Actus Nutrition from milk-derived lactose. While GOS has been added to infant formulas for several years, Actus is the first company to produce the prebiotic at a price point feasible for use in the animal feed industry.
Our experiment tested the effects of GOS on growth of pigs when supplemented into gruel creep diets (5% inclusion) and phase 1 nursery diets (3.8% inclusion, Fig. 1). Also, on day 22 of age (one day before weaning) and day 31 (one-week post-weaning), we measured intestinal parameters, including microbial diversity and SCFA proportions.
Pigs fed gruel creep during farrowing were 6% heavier than controls by day 14 and 12% heavier by day 23 (Fig 2; P < 0.05; See YouTube Short). This translated into daily weight gains being greater for creep-fed pigs, with a 17% increase in the first week (D7-D14) and 26% in the second week (D14-D21; data not shown). Effects of gruel creep feeding extended into the nursery. By day 58, pigs that had been fed creep containing GOS were 1.6 kg heavier than those lacking GOS and were 1.9 kg heavier than pigs that were not fed creep (Fig. 3).
When GOS was added to the phase 1 nursery diet, pigs grew 34% faster than controls during the first week (Fig 4, P < 0.05), and the increase was sustained with an overall (D23-58) increase of 8% (P < 0.05). Increased feed intake (Fig 4) accompanied the increased growth, with GOS-fed pigs eating 11% more in phase 1 (P = 0.06), 8% more in phase 2 (P = 0.02), and 6% more overall (P = 0.06). Furthermore, GOS increased feed efficiency (gain:feed) by 15% during phase 1 (P < 0.05). There were no differences in fecal diarrhea scoring across treatments.
Before weaning, gruel creep feeding and GOS supplementation had no effect on cecal SCFA composition at D22. However, by D31 (one-week post-weaning), pigs that had been fed creep without GOS showed reduced acetate and increased valerate compared to pigs not feed creep. Pigs fed GOS pre-weaning had the highest acetate and an intermediate valerate level.
In the nursery, GOS in the phase 1 diet increased cecal butyrate and decreased propionate (Fig. 5), indicating a GOS-induced shift in SCFA proportions. The presence of Bacteroidetes, which can produce propionate, was relatively reduced in GOS-fed pigs.
Microbial diversity analysis showed that the weaning event itself caused the most significant shift in bacterial communities, seen through beta-diversity measurements (Fig. 6). Alpha diversity (not shown), which measures species richness within samples, increased in creep-fed pigs, suggesting a more varied bacterial community, while GOS had no effect on alpha diversity measured post-weaning.
Our pre-weaning analysis only compared creep-fed pigs to control pigs because no effects of GOS were observed. Predominant bacterial families were Ruminococcaceae, Lachnospiraceae and Lactobacillaceae, and at the genus level, creep-fed pigs had higher relative abundance of Fructobacillus, Incertae Sedis, Lactococcus, and Prevotella NK3B31, while Lachnoclostridium and UBA1819 decreased (P < 0.05).
Fermentation acid (SCFA) profiles can be altered by prebiotics, which accompany altered microbial growth in the hindgut. Because mammalian enzymes can't break down fibrous plant material, bacterial fermentation is necessary for breaking down the beta-glycosidic bonds in GOS. Studies have shown that adding GOS increases lactic and acetic acid in the proximal colon and butyric acid in the distal colon, with a reduced pH in the proximal colon [1].
In the nursery phase, increased fiber intake post-weaning led to changes in SCFA profiles, with pigs fed GOS in phase 1 showing a decrease in propionate and an increase in butyrate. Studies on oligosaccharides like soy galactooligosaccharides have shown increases in propionate and butyrate, while mannan-oligosaccharides decreased butyrate and propionate while increasing acetate [2, 3]. The type of oligosaccharide affects microbial populations and SCFA profiles differently.
Butyrate is particularly important due to its positive effects on growth, nutrient absorption, and intestinal health. Protected butyrate supplementation has been shown to improve intestinal microflora and barrier function [4].
In our study, GOS feeding increased the proportion of butyrate, which was positively correlated with improved average daily gain (Fig. 7). While we did not directly supplement butyrate, the increase in butyrate could have contributed to improved intestinal health and piglet growth. Further research is needed to confirm these findings.
The hindgut microbiome is influenced by the addition of prebiotics, but the most significant factor in microbial changes in piglets is the weaning event. The transition from milk to a fibrous diet drives rapid maturation of the piglet microbiome. Studies by Bian et al. [5] and Gueverra et al. [6] confirm that weaning significantly impacts microbial diversity, with Bian et al. highlighting its greater importance than breed or nursing sow.
Our PCoA analysis, comparing pre- and post-weaned pigs (Fig.6), showed similar results to Gueverra et al., with little overlap between treatment groups. Based on these findings, we further investigated whether prebiotic GOS supplementation would affect microbial communities in pre- or post-weaned pigs.
The addition of GOS to pre-weaning gruel diets did not significantly affect the microbiota; however, creep feeding itself creep feeding (regardless of GOS) altered several microbiota. Fructobacillus, Incertae Sedis, and Eubacterium xylanophilum increased the most, which is often observed post-weaning due to the dietary shift. The gruel diet, containing fermentable ingredients like oats, soy isolate, and GOS, likely supported the growth of microbes that utilize fiber. This aligns with previous studies showing an increase in genera from the Lactobacillaceae, Ruminococcaceae, and Lachnospiraceae families after weaning.
On the other hand, Lachnoclostridium and UBA1819 decreased in GOS-fed pigs, though the change was less pronounced than the increases observed in other microbes. Post-weaning, Fusicatenibacter, Incertae Sedis, and Collinsella increased in pigs fed GOS in phase 1 diets, with all being beneficial hindgut fermenters. Fusicatenibacter produces enzymes that break down sugars, while Collinsella is linked to increased butyrate and propionate production. Campylobacter, a pathogenic bacterium, decreased significantly in the GOS-fed group.
While individual microbiota are important, the microbiome should be viewed as a complex system. GOS supplementation shifts several genera, but the entire microbial network influences phenotypic changes. Advanced sequencing techniques will provide clearer insights into these microbe-host interactions.
Overall, our study suggests that GOS supplementation, along with creep feeding, positively impacts beneficial microbes and SCFA production, potentially supporting a smoother weaning transition and improving early-life growth and health of young pigs.
ReferencesThis summary draws from our previous full-length publications, references Boston et al. 2022 [7] and Boston et al. 2024 [8] which are freely available online. During the preparation of this work the authors used Chat-GPT to assist in summarizing text. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.
1. Tzortzis G, Goulas AK, Gee JM, Gibson GR. A novel galactooligosaccharide mixture increases the bifidobacterial population numbers in a continuous in vitro fermentation system and in the proximal colonic contents of pigs in vivo. J Nutr. 2005;135(7):1726-31.10.1093/jn/135.7.1726
2. Smiricky-Tjardes MR, Grieshop CM, Flickinger EA, Bauer LL, Fahey GC, Jr. Dietary galactooligosaccharides affect ileal and total-tract nutrient digestibility, ileal and fecal bacterial concentrations, and ileal fermentative characteristics of growing pigs. J Anim Sci. 2003;81(10):2535-45.10.2527/2003.81102535x
3. Li YS, San Andres JV, Trenhaile-Grannemann MD, van Sambeek DM, Moore KC, Winkel SM, et al. Effects of mannan oligosaccharides and lactobacillus mucosae on growth performance, immune response, and gut health of weanling pigs challenged with escherichia coli lipopolysaccharides. J Anim Sci. 2021;99(12).10.1093/jas/skab286
4. Claus R, Gunthner D, Letzguss H. Effects of feeding fat-coated butyrate on mucosal morphology and function in the small intestine of the pig. J Anim Physiol An N. 2007;91(7-8):312-8.10.1111/j.1439-0396.2006.00655.x
5. Bian GR, Ma SQ, Zhu ZG, Su Y, Zoetendal EG, Mackie R, et al. Age, introduction of solid feed and weaning are more important determinants of gut bacterial succession in piglets than breed and nursing mother as revealed by a reciprocal cross-fostering model. Environ Microbiol. 2016;18(5):1566-77.10.1111/1462-2920.13272
6. Guevarra RB, Hong SH, Cho JH, Kim B-R, Shin J, Lee JH, et al. The dynamics of the piglet gut microbiome during the weaning transition in association with health and nutrition. J Anim Sci Biotechno. 2018;9(1):54.10.1186/s40104-018-0269-6
7. Boston TE, Wang F, Lin X, Leonard S, Kim SW, McKilligan D, et al. Gruel creep feeding accelerates growth and alters intestinal health of young pigs. Animals. 2022;12(18):2408
8. Boston TE, Wang F, Lin X, Kim SW, Fellner V, Scott MF, et al. Prebiotic galactooligosaccharide improves piglet growth performance and intestinal health associated with alterations of the hindgut microbiota during the peri-weaning period. J Anim Sci Biotechno. 2024;15(1):88.10.1186/s40104-024-01047-y
Boston, Weng, Lin, Kim, Fellner and Odle are with the Department of Animal Science, College of Ag and Life Sciences; Ziegler and Blikslager are with the Department of Clinical Sciences; and Landegehm is with the Department of Molecular Biomedical Sciences, College of Veterinary Medicine, all with North Carolina State University. Scott is with Actus Nutrition.
