Study On Technology Of Fermented Liquid Cereal Grain Feed And Its Effects On Growth Performance And Faecal Microbiology In Piglets

Weaning age has declined over time in order to increase sow productivity and limit disease transfer. Early-weaning induced the stressor of piglet in environmental, behavioral and immunological aspects when food of piglet switched abruptly from sow milk containing digestible nutrients to dry feed. The stressor of early-weaning represents as feed intake decline, villus atrophy, diarrhea, lower digestion and absorption, and body weight loss. Traditional diets and management has faced serious challenges. Fermented liquid cereal grain feed(FLG) is similar to sow milk which is characterized as reducing pH by increasing lactic acid, improving gastrointestinal ecology and minimizing microbial degradation of free amino acids.It has been considered as the most promising means of reducing weaning stressors. At present, there are few researchs on fermented feed in China.The present study was carried out to study liquid diets of fermented grains from the fermentation process, micro-ecological structure and evaluation of animal experiments.Experiment 1:Fermentation technology of cereal feedThis trail was carried out to study the effects of technology parameters on quality of fermented grain with index of pH and antibacterial activity on Escherichia. coli. A continuous fermentation technology at stable 25℃was adopted. The first fermentation period lasted 48h and the rest periods all lasted 24h,50% fermentation products were removed and renewed between two periods. The technology parameters included: microbial source in the first fermentation cycle (inoculation fermentation, natural fermentation), the ratio of water and grain (1:1,1:2.5) and processing cereal (mixed fermentation or independent fermentation). The results showed that pH of the inoculated fermentation system was lower as the ratio between corn and water as 1:2.5 than as 1:1, significantly. pH of the inoculated fermentation by adding Lactobacillus plantarum was lower than the natural formation system. The both could inhibit the growth of Escherichia coli completely as the ratio between maize and barley as 1:1, and its role was superior to the separated fermentation of maize or barley. When the ratio between corn and water was 1:2.5, the inoculated fermentation system by adding Lactobacillus plantarum performed the faster pH descending speed as the ratio between maize and barley as 1:1 than the separated fermentation of maize or barley. In this process, pH decreased below 5.0 or 4.0 after 12-hour or 24-hour respectively, which contribute to its inhibition role on the growth of harmful bacterial (such as E.coli.). The best fermentation parameters include: inoculation of Lactobacillus plantarum, the ratio of water and grain as 1:2.5 and fermentation with barley and corn mixture.Experiment 2:Microecological flora of continuous liquuid fermentation systemA real time PCR assay and DGGE were utilized to study the structure of biological bacteria and the dynamic of Escherichia coli and Lactobacillus. The results showed that structure of micro-ecological changed significantly in the first fermentation period. The diversity and similarity of DGGE profiles between beginning and ending fermentation were different. Relative abundance of some advanced band was significantly different, harmful bacteria was reduced and beneficial Lactobacillus bacteria increased significantly. The structure of micro-ecological and the main bacteria between different fermentation periods were similar. The average content of Escherichia coli was 5.891oglOCFU/g, that of Lactobacillus bacteria was 9.581oglOCFU/g. These results suggested that Lactobacillus plantarum can quickly took advantage when inoculation of Lactobacillus plantarum in the first fermentation period and then formed a stable structure of micro-ecological. The product of fermentation was good.16S rDNA PCR/DGGE can be used for detecting the fermentation process quality.Experiment 3:Effects of fermented grain on gastrointestinal ecology and growth performance in piglets.The effects of fermented cereal grains on gastrointestinal ecology and growth performance of 14d early-weaned piglets were investigated. Results show that the fermented cereal grains could significantly improved weight gain of pigs in the first 2 weeks after weaning. Average daily feed intake of pigs feeding the liquid diet increased 41.7%(P＜0.01) than pigs feeding the dry pellet diet. Similarly, gain and gain/feed of pigs fed liquid diet increased 107.5%(P<0.01)and 36.9% than that of feeding dry diets. Results of serum analysis showed that pre-albumin content increased 36.9%, which is consistent with growth performance. Results of 16SrDNA PCR/DGGE assay showed that all bands of control groups were similar, as well as all test groups (about 0.6). Relative abundance of some advantages band changed significantly, which show that fermented grain feed could influence the structure of gastrointestinal ecology in piglets. The real time PCR results show that the content of Escherichia coli and Lactobacillus in fecal decreased 84.9% (P<0.1), and increased 145.9%(P>0.05) respectively, the ratio of Escherichia coli and Lactobacillus bacteria increased 10.3 fold (P<0.05).In conclusion, this study established a continuous liquid fermentation of feed grains, and clarified the dynamic changes of the structure microbial ecology and some main bacteria during the fermentation process. We also found that feeding prepared fermentation feed alone and adding the remaining dietary ingredients immediately before feeding could improve growth performance, and gastrointestinal ecology in 14-day-old weaned pigs.