Study Of A Complex Lactobacilli Preparation And Its Function On Piglets

Lactobacilli strains were isolated from gastrointestinal(GI)tract mucosa and screened out to develop a complex lactobacilli preparation, which would alleviate piglet weaning stress. Two animal experiments were conducted to study the action mode of the preparation in piglets. On the basis of stress-tolerance and probiotic characteristics, Lactobacillus gasseri was selected from 1220 strains in stomach and L. reuteri from duodenum, L. acidophilus from jejunum and L. fermentum from colon, were also singled out from 5789 intestinal strains. The biological characteristics of four strains of lactobacillus were determined and fermentation parameters of these lactobacilli were optimized by means of uniform design. Lactobacilli survivability after 75℃treatment for 15 min, pH2.0 treatment for 6 h and storage for 1 month, respectively, were measured. L. gasseri survivability after 75℃, storage, and pH2.0 treatment was 72%, 37.8%, 133%, respectively and fermentation parameters were as follows: culture time 20 h, glucose 110 g/L, sucrose 60 g/L, peptone 30 g/L, yeast extract 30 g/L, and ammonium citrate 2 g/L. L. reuteri survivability after 75℃, storage, and pH2.0 treatment was 31.3%, 85.5%, 34.4%, respectively and fermentation parameters were as follows: culture time 20 h, glucose 10 g/L, sucrose 60 g/L, peptone 30 g/L, yeast extract 2 g/L, and ammonium citrate 2 g/L. L. acidophilus survivability after 75℃, storage, and pH2.0 treatment was 62.5%, 59%, 69.5% respectively and fermentation parameters were as follows: culture time 20 h, glucose 110 g/L, sucrose 10 g/L, peptone 5 g/L, yeast extract 30 g/L, and ammonium citrate, 12 g/L. L. fermentum survivability after 75℃, storage, and pH2.0 treatment was 45.1%, 78.4%, 80.9%, respectively and fermentation parameters were as follows: culture time 20 h, glucose 10 g/L, sucrose 60 g/L, peptone 30 g/L, yeast extract 30 g/L, and ammonium citrate 12 g/L. The optimal ratios of four lactobacilli bacteria in complex preparation were determined in uniform design. The proportion of lactobacilli is as follows: L. gasseri : L. reuteri : L. acidophilus : L. fermentum =2 : 3 : 5 : 2. Twelve pigs (7.65±1.10 kg BW), weaned at 28 d, were allocated randomly into 2 groups. One group was provided with water containing the preparation and the other with tap water as control before piglet was orally administered with E. coli on the 8th d. In the following 7 d, diarrhea index and diarrhea incidence were decreased by 66 and 69.1%, respectively, in lactobacilli treated group. The lactobacilli significantly decreased E. coli, coliforms and aerobes counts but increased lactobacilli, bifidobacteria and anaerobes counts in digesta and mucosa of most sections of GI tract. Thirty-six piglets weaned at 28 d (7.65±1.09 kg BW) were allocated randomly into two groups with six pens per group and three pigs per pen. Half of piglets were fed a non-medicated basal diet with lactobacilli preparation and the other with 50 mg/kg carbadox as control. The lactobacilli preparation significantly improved piglets ADG by 30.2% and ADFI by 23.9% compared with carbadox (P<0.05) during the first 2 wks after weaning. From d 15 to d 21, improved growth performance was not observed in lactobacilli treated group. The lactobacilli significantly increased lactobacilli, bifidobacteria, anaerobes, E. coli, coliforms, and aerobes counts in digesta and mucosa of most sections of GI tract. Digestibility of nitrogen and total phosphorus was only significantly increased (P<0.05). BUN was decreased in lactobacilli group (P<0.01). The results from these experiments showed that the complex lactobacilli preparation improved performance of piglets in the first 2 wks and resistance to E. coli challenge mainly by improving microbial balance in GI tract.