Application of Bacillus spp. spores in the drinking water and environment on the growth performance and gut microbiome in weaner pigs

Abstract

In this project the impact of Bacillus probiotics on the production performance and microbial gut diversity in weaner pigs were investigated. Two production units were used, namely individual housing units and group housing units each with a probiotic treatment and a control. A total of 167 weaner pigs, 21-days of age, were purchased from a commercial farm with 40 pigs allocated to individual pens and the remainder of animals housed in group pens with ±15 pigs per pen and a stocking density of 0.95 m2 per pig. Group housed pigs were kept in the trial until 57 days of age and pigs in individual pens were kept in the trial until 63 days of age. Three products from Chrisal Africa (Pty) Ltd were used, which included a PIP Animal Housing cleaner containing probiotic enzymes (3 % solution applied at 1 L/100 m2 for cleaning and 5 % solution for flushing the waterlines), PIP Environmental Enhancer containing Bacillus spores (applied as a mist at 1 L/200 m2) and PIP Water Plus containing Bacillus spores (0.02 % solution once a day). Growth performance was measured as well as microbial gut diversity using 16S rRNA sequencing analysis on faecal samples of the individually housed pigs. Group housed pigs on the probiotic treatment gained less weight than the control at 21-28 days (-230 g) and 49-57 days (-1420 g), with no significant difference in feed intake and higher feed conversion ratios at 21-28 days (+0.19 g/g) and 35-42 days (+0.11 g/g). Individually housed pigs on the probiotic treatment gained less weight than the control at 35-42 days (-0.73 g), had higher feed intake at 49-60 days (+1530 g) and higher feed conversion ratios at 35-42 days (+0.19 g/g) as well as 49-60 days (+0.3 g/g). Changes that were noted between treatments in the microbial populations included significantly more Ruminococcaceae (+4.58 %) and Streptococcaceae (+2.49 %) in the probiotic treatment at 35 days of age as well as significantly more Erysipelotrichaceae (+0.7 %), Lactobacillaceae (+3.1 %) and Streptococcaceae (+2.67 %) in the probiotic treatment at 49 days of age. No differences were detected at 63 days of age. Results indicated negative effects on growth and performance for probiotic treated pigs, although microbial gut populations of probiotic treated pigs showed increased amounts of beneficial microbes during the first four weeks after weaning.