Optimal use of feed additives could promote intestinal health in pigs

Modulation of intestinal microbiota toward a more beneficial microbial community can be a key factor in enhancing intestinal health, and thus boosting the growth performance of nursery pigs, noted the authors of a review published in Animal Nutrition​​.​

The aim of the paper was to provide the latest insights into the interaction among intestinal microbiota, dietary components, and the intestinal health of pigs.

The pig’s diet and its associated components such as feed additives are the main factors affecting the microbial composition and is central in stimulating a beneficial population of microbiota, said the reviewers. 

"The use of feed additives to modulate the microbiota at a specific level should consider the existing microbial community before nutritional interventions are put in place in order to promote a more precise response," ​stressed the authors.

Absorption of nutrients 

They outlined how the small intestine is a key site to evaluate the interaction of the microbiota, diet, and host because it is the main site for digestion and absorption of nutrients and plays an important role within the immune system.

And the mucosa-associated microbiota should be evaluated when analyzing the interaction among diets, microbiota, and health, they said.

“Prevotella, Lactobacillus, and Bifidobacterium have great abundance in the mucosa and are associated with health benefits but  Campylobacter, Clostridium, Veillonella, and Helicobacter are potentially harmful or associated with intestinal dysbiosis.”​

These bacteria could be used as a biomarker to predict responsiveness to dietary interventions and more specific nutritional intervention depending on genetics, on-farm management, and current nutritional management, said the reviewers.

Pro, pre and postbiotics​

The use of probiotics should account for the intestinal microbiota status before supplementation (Barba-Vidal et al., 2018), they added.

The team cited Suez et al. (2018), who found that probiotic supplementation in humans can disturb rather than support the intestinal microbiota recovery back to baseline following antibiotic treatment.

There is evidence, continued the reviewers, that the host gene expression and the baseline microbiota can affect the probiotic colonization in the intestinal mucosa in humans (Zmora et al., 2018).

“These findings may indicate that the role of probiotics in the modulation of the intestinal microbiota is more effective in preventing disease-associated dysbiosis by promoting a healthier microbiota, rather than recovery of the microbiota following disruption. Therefore, the approach in dietary probiotic supplementation should consider both the host characteristics and the baseline intestinal microbiota.”​

In terms of prebiotics, the researchers noted work indicating that oligosaccharides can shift the intestinal microbiota toward species that play an important role in the immune system.

The authors reported inconsistencies in studies evaluating the effects of yeast-based postbiotics on the immune response of pigs and they said further investigation considering the interaction among postbiotic, mucosa-associated microbiota, and immune system is required.

Enzymes​

Supplementation of multi-enzymes may show a synergetic effect due to the complexity of plant cell wall components and therefore the variety of oligosaccharide and bio-compounds released, they noted.

According to a paper from Li et al. (2020a), a multi-carbohydrase complex containing xylanase, β-glucanase, and pectinase recovered the intestinal microbiota homeostasis disrupted by ETEC challenge in ileal and colonic digesta of newly weaned pigs.

The reviewers also cited work by Kim et al. (2018) with those researchers reporting that the inclusion of multi-enzymes containing xylanase, amylase, β-mannanase, protease, and phytase increased the count of Lactobacillus spp​. and decreased of E. coli​ and Clostridium spp​. in digesta of ileum and cecum.

Essential oils​

Looking at essential oils (EO), the reviewers said their proposed antimicrobial mechanism is related to the alteration of the cell wall and cytoplasmic membrane, increasing the cell permeability and reducing the virulence function (Nazzaro et al., 2013).

Man et al. (2019) analyzed (in vitro) the inhibitory and bactericidal activity of various EO against Staphylococcus aureus​, Enterococcus​ faecalis,​ E. coli​, Klebsiella pneumoniae​ and Pseudomonas aeruginosa​, with those researchers concluding that the most active EO were oregano, thyme, and lemon oil because of the great concentration of terpenes and terpenoids in these oils.