Evonik: Bacillus subtilis-based probiotics, an alternative to AGPs for improving performance and health of weaned pigs

Health challenges in weaned piglets

 

Pigs are often exposed to pathogens and stressors in commercial production conditions.

 

Weaning is a stressful period associated with multiple stressors, e.g. separation from mother sows and change of diet. After weaning, digestive system is immature and feed intake of piglets is low, which causes intestinal inflammation and impairs gut morphology, increasing the amount of undigested feed in the large intestine for the proliferation of pathogenic bacteria particularly E. coli K88 (F4) and F18, and a reduction of beneficial bacteria known as dysbiosis. Microbiota dysbiosis coupled with the immature digestive system of weaned pigs can impair the barrier function of the small intestine and increase the incidence of diarrhea, reducing growth performance, increasing morbidity, and mortality of weaned piglets (Lallès et al., 2004). Post-weaning diarrhea is more severe during the first two weeks after weaning and is mainly caused by enterotoxigenic E. coli F4 (K88) and F18 resulting reduced performance, increased mortality, and economic losses.

 

Due to public concerns about potential antibiotic resistance risks related to human health, one of the current interests in nursery pig nutrition is to adopt antibiotic-free feeding systems. This requires developing feed additives that could be used as in-feed antibiotics alternatives in pig feeding strategies. Probiotics are among the key alternative solutions to antibiotics and are live organisms which helps to promote intestinal health by modulating intestinal microbiota, enhancing intestinal morphology and immunity, and increasing short chain fatty acids (SCFA) production in the hind gut.  Thus, probiotics are promising for preventing gut health diseases, however, important factors for effectiveness are strain, strength, stability, shelf life, safety, and scientific backing.

 

GutPlus^®  enhances gut health and performance (He et al., 2020):

 

Bacillus spp. probiotics are considered to be suitable probiotics due to their ability to form spores that enable them to endure harsh environmental and pelleting conditions and to germinate in the gut of pigs after passing the stomach.

 

GutPlus^® is a probiotic, based on Bacillus subtilis 32540, specially developed by Evonik, to inhibit pathogens, including E. coli, Clostridium perfringens, Streptococcus suis, Enterococcus Cecorum, Strep. aureus, and produce secondary (antimicrobial) metabolites and lactic acid. It is also compatible with organic acids and antimicrobial growth promoters (AGP). Recent studies showed that a probiotic containing Bacillus subtilis DSM 32540 (GutPlus^®), promotes a healthy gut environment by improving gut morphology, gut microbiota balance and strengthening immune status, contributing to lower diarrhea rate and improved growth performance of weaned pigs.

 

In a commercial trial conducted in China, supplementing GutPlus^® improved intestinal morphology in jejunum and ileum and increased final body weight compared with the control diet, but it was not different from AGP treatment (0.04 kg/ton virginiamycin). Diarrhea rate was reduced by addition of AGP or probiotic compared to control group (Figure 1; Facts & Figures 14142).

Figure 1. Diarrhea rate of pigs fed control diet, diet with antibiotics, or diet with probiotics

  

To validate the effectiveness against E. coli, two studies were conducted to evaluate the effect of GutPlus^®  in piglets challenged with E. coli K88 or F18.

 

A study was conducted at South Dakota State University (the United States) using weaned pigs orally challenged with a sub-clinical dose of K88 strain E. coli and fed three experimental diets, a corn-soybean meal basal diet (negative control; NC); the basal diet with antibiotic growth promoters (AGP; 0.25 % Neomycin + oxytetracycline); and the basal diet supplemented with Bacillus subtilis DSM 32540 (500 g/ton; GutPlus^®). The results demonstrated that supplementation of probiotic, GutPlus^®  improved growth performance, lessened severity of diarrhea, improved morphology of jejunum and ileum (Table 1) of weaned pigs challenged with E.coli K88 (Park et al., 2020).

  

Table 1. Effects of the dietary inclusion of antibiotic or probiotic (GutPlus^®) on morphology of jejunum and ileum of piglets under E. Coli k88 challenge (day 18)

 

a,b,cWithin a column, means without a common superscript differ (P < 0.05). NC= Negative control (basal diet), AGP= basal diet supplemented with antibiotics, GutPlus^®= basal diet supplemented with Bacillus subtilis DSM 32540.  

  

Another study conducted at the University of California, Davis, showed that supplementation with GutPlus^® resulted in greater body weight (day 7, 12 and 21) and a reduction in the frequency of severe diarrhea (score >4) in pigs under E. coli F18 challenge (He et al., 2020; Figure 2).

Figure 2.  Effect of GutPlus^® on diarrhea and growth of weaned pigs challenged with E. coli F18

 

GutPlus^® alleviate heat stress in pigs

 

Pigs exposed to heat stress undergoes imbalanced gut microbiota which may compromise intestinal morphology and integrity. Feeding study conducted in Mexico concluded that probiotics supplementation can help pigs to maintain a healthy intestinal environment under heat stress conditions. Results from this study demonstrated that supplementation with Bacillus subtilis DSM 32540 at 1 × 106 CFU per gram of feed was effective in counteracting some of the negative effects on performance (Figure 3), body temperature, and intestinal histology of pigs caused by heat stress (Gonzalez et al., 2024).

Figure 3.  Effect of GutPlus^® on ADG and FCR pigs under both thermal neutral (TN) and heat stress (HS) conditions

       º can replace AGP without affecting pig performance