Improving piglet growth rates and fecal metabolites
Using a recommended dose of a two strain Bacillus subtilis probiotic
By Karyn Duddeck, Alexandra Smith and Young Dal Jang
One of the most stressful events in the pig’s life is weaning as it involves a sudden change of diet from milk to solid form as well as social and living environment adjustments. One of the common issues with newly weaned pigs is gastrointestinal disorders such as post-weaning diarrhea associated with pathogenic bacteria infection.
Probiotics are considered an alternative to antibiotics that are widely used in the swine diets and beneficial to improve intestinal health of post-weaning piglets by inhibiting pathogenic bacteria, enhancing beneficial bacterial proliferation, stimulating immune system, degrading toxins, and producing short chain fatty acids (SCFA) that are potential energy sources for piglets.
It has been reported that dietary supplementation of probiotics in the swine diets, especially for nursery pigs, could improve gut microbiota, gut immune system and nutrient utilization so that it could reduce weaning stress and improve growth and survival rate.
The efficacy of probiotic products is dependent on a number of factors such as the species and strains of the microbe, product formulation (single or multi-strain probiotics), the health condition being targeted as well as the dose of product administered.
Although the definition of probiotics is that they are live microorganism that benefit the health of the host when administered in adequate amounts, there is limited information about the effect of dose of dietary probiotics on growth performance and fecal metabolites of nursery pigs.
Therefore, an experiment was conducted to evaluate the effects of dietary supplementation with the recommended and high dose of a two-strain Bacillus subtilis probiotic product developed to reduce effects of F18 enterotoxigenic Escherichia coli (ETEC), a common cause of diarrhea in piglets post weaning, on growth performance and fecal SCFA concentrations of nursery pigs.
Effects of Bacillus subtilis supplementation level on growth performance and fecal metabolites in nursery pigsA total of 54 piglets (initial body weight: 9.1 ± 1.3 kg) weaned at 26.9 ± 2.0 d of age were allotted into three treatments in three replicates with six pigs per pen (three barrows and three gilts) based on body weight, breed, sex and age for a 28-day growth trial.
All piglets were housed in raised-deck nursery pens (1.32 × 1.63 m2) in an environmentally controlled nursery facility.
Treatments were:
Control: no probiotics supplementation
Pro1x: 3.75 × 108 CFU/g Bacillus subtilis supplementation (0.05% supplementation level resulting in 1.875 × 105 CFU/g diet)
Pro10x: 3.75 × 109 CFU/g Bacillus subtilis supplementation (0.05% supplementation level resulting in 1.875 × 106 CFU/g diet).
The probiotic products were obtained from Arm & Hammer Animal and Food Production and consisted of a blend of two strains selected to inhibit pathogenic F18 E. coli strains often implicated in piglet diarrhea (The ScienceHearted Center, Waukesha, Wisconsin).
All piglets were fed corn-soybean meal-based diets formulated to meet or exceed the nutrient requirement estimates of NRC (2012) with free access to water and feed for the 28 d of the entire experimental period. Two diet phases were used for d 0-14 (Phase 1) and d 14-28 (Phase 2) post-weaning. The probiotic product was supplemented in the diet at the assigned levels by replacing corn.
Body weight of each pig and feed consumption were recorded weekly at d 0 (study initiation), d 14 and d 28 post-weaning for calculation of average daily gain, average daily feed intake and gain to feed ratio.
Fecal samples were collected from two representative pigs in each pen (average body weight) by rectal palpation at d 28 post-weaning and analyzed for fecal SCFA concentrations.
In growth performance, the body weight at d 14 post-weaning (P=0.055; Table 1) and average daily gain for d 0 to 14 post-weaning (P<0.05) were greater in the Pro1x treatment than the control and Pro10x treatments.
In the fecal SCFA concentrations (Figure 1), the butyrate concentrations were greater in the Pro1x than the control and Pro10x treatments (P<0.05) and the acetate and propionate concentrations were greater in the Pro1x treatment than the Pro10x treatment with the intermediate value in the control treatment (P<0.05).
The butyrate is an important energy source for intestinal epithelial cell and an increase of butyrate concentrations was only observed in the Pro1x treatment but not in the Pro10x treatment, which indicates that overdose of probiotics to nursery pig diet might not be beneficial for fecal metabolite production and piglet growth performance.
In conclusion, dietary Bacillus subtilis supplementation of two strains selected to reduce effects of pathogenic E. coli to nursery diets at the recommended dose improved growth rate in the early post-weaning period and increase fecal SCFA concentrations. A higher dose of the probiotic did not improve the measured performance parameters over that of the control piglets.
AcknowledgementThis experiment was supported by Undergraduate Research Scholarly and Creative Activity Undergraduate Stipends and Expenses Grant and McNair program at University of Wisconsin – River Falls, and Arm & Hammer Animal and Food Production.
Duddeck is an undergraduate student at University of Wisconsin – River Falls; Smith is director of Innovation and Product Development at Arm & Hammer Animal and Food Production; and Jang is a former assistant professor at University of Wisconsin – River Falls and currently an assistant professor at University of Georgia.
