Effects of Bacillus subtilis on growth performance and intestinal flora of weaned piglets

A large number of studies have shown that supplementing  Bacillus subtilis  in the diet of weaned piglets can reduce the number of harmful bacteria Escherichia coli in the intestinal tract and increase the number of beneficial bacteria Lactobacillus in the intestinal tract of piglets, thereby improving the growth performance of piglets. The article preliminarily evaluated the antibacterial properties of probiotics by establishing an in vitro antibacterial experiment, and on this basis, carried out animal feeding experiments to verify its application effect.
Materials and Methods
A Bacillus strain was analyzed from the feces of white-feathered broilers in the early stage, identified as Bacillus subtilis by 16 sRNA gene, and named Bacillus subtilis-Ⅱ after isolation and purification.
66 healthy weaned piglets at 28 days of age were divided into 2 treatment groups according to the principle of consistent body weight, each treatment group had 3 pens, and each pen contained 11 weaned piglets. The treatment groups were designed as follows: treatment group 1 (group A) was fed the basal diet; treatment group 2 (group B) was supplemented with 500 g/t Bacillus subtilis preparation (viable count: 1 × 1010) on the basis of the basal diet. cfu/g). The feeding cycle was 7 d.
During the experiment, the temperature of the farrowing room was kept at 23-27°C to ensure that the piglets had sufficient water and light every day; they were fed 3 times a day at regular intervals to satisfy the free feeding of the piglets. During the feeding period, pay attention to the health status of the piglets at any time, make timely treatment and make records.
All experimental pigs were weighed at 9:00 am on the 8th day of the experiment, and the average daily weight gain, average daily feed intake, feed-to-weight ratio and diarrhea rate of weaned piglets were calculated.
At 17:00 on the seventh day of the experiment, the defecation of each experimental pig was observed, and fresh feces were collected in time to detect the number of Escherichia coli and Lactobacillus.
SPSS 17.0 statistical software was used for statistical analysis of growth performance, intestinal flora and other data, and T-test data was used for statistical analysis. The inhibition zone data of Bacillus subtilis were analyzed by one-way analysis of variance and Duncan, s multiple comparison. P ≤ 0.05 indicates a significant difference, and 0.05 < P ≤ 0.1 indicates a trend towards difference.
result
The experimental data showed that the strain of Bacillus subtilis had bacteriostatic effects on Escherichia coli K88, Salmonella choleraesuis and Salmonella pullorum, and the differences in the antibacterial effects were significant (P ＜ 0.05). At the same time, Bacillus subtilis had the best bacteriostatic effect on Salmonella pullorum. In addition, Bacillus subtilis has no inhibitory effect on Lactobacillus reuteri.
The addition of Bacillus subtilis to the feed significantly increased (P ＜ 0.05) the final weight and average weight gain of weaned piglets, and significantly decreased the feed-to-weight ratio and diarrhea rate (P ＜ 0.05); but there was no significant difference in the average daily feed intake (P ＜ 0.05). > 0.05).
The addition of Bacillus subtilis to the diet could significantly reduce (P ＜ 0.05) the number of Escherichia coli in the intestine of weaned piglets; the number of Lactobacillus in the intestine of weaned piglets was significantly increased (P ＜ 0.05).
Discussion
The results of the study show that this strain of Bacillus subtilis has good bacteriostatic effect on Escherichia coli K88, Salmonella choleraesuis and Salmonella pullorum, the main pathogenic bacteria in the intestinal tract of livestock and poultry, which is consistent with previous studies.
This experiment investigated whether Bacillus subtilis has an effect on the growth performance of piglets 7 days after weaning. The results showed that the addition of Bacillus subtilis in the diet could significantly increase the final weight and average daily gain of piglets, and significantly reduce the feed-to-weight ratio and diarrhea rate of piglets. This result is basically consistent with previous reports.
Conclusion
In this study, the Oxford cup method was used to evaluate the bacteriostatic properties of Bacillus subtilis from in vitro experiments. Combined with the experimental results of adding Bacillus subtilis to the diet to improve the growth performance of weaned piglets, it showed that this strain of Bacillus subtilis can be used in feed, Feed additives and the actual breeding of livestock and poultry to improve the growth performance of piglets. At the same time, the test also established a scientific and efficient research basis for the evaluation of the use of feed probiotics.