The Preparation Of A Novel Yeast Culture And Its Effect On Growth Performance,Apparent Nutrient Digestibility And Fecal Microbiota Of Weaned Piglets

As a widely used probiotics, yeast culture(YC) is rich in nutrients. Nowadays, the quality and effect yeast cuture products are different in the market. In the development of YC, the quality of the product is mainly decided by the performance of strains. As a result, the excellent yeast strains are the basis of the research and application of yeast culture. Massa Medicata Fermentata(MMF), the Chinese traditional herbal leaven and sourdough are similar to modern yeast culture, but contain complex microbial communities, and include the basis strains of the preparation of yeast culture--Saccharomyces cerevisiae. This test will produce a compound yeast culture by combing strains from natural fermentation with modern fermentation technology and explore its effect on performance of weaned piglets. The main experimental results were as follows:1) Seven yeast strains were isolated from Jianqu in Hebei, Shenqu in Beijing, Shenqu in Sichuan and sourdough using traditional culture method, name J1, J2, BS1, BS2, SS1, SS2 and JI1. They were identified as Saccharomyces cerevisiae through morphological characteristics, biochemical identification and molecular identification. But the type strain number of J2 and BS2, J1 and SS1 were same, actually five kinds of Saccharomyces cerevisiae J1(SS1), J2(BS2), BS1, SS2 and JI1. From the aspect of phylogenetic tree, the similarity among J1(SS1)、J2(BS2)、BS1 and SS2 strains can reach 99%, the similarity between JI1 and the others is 66 percent. So JI1 is a different subtype, which can assimilate starch.2) We compared the feature of SS2, JI1 with Saccharomyces cerevisiae CGMCC2.614. From the point of growth curve, the growth characteristics of three strains were roughly the same. Three strains have differences in yeast polysaccharide production measured by phenol sulfuric acid method, JI1 > SS2 > CGMCC2.614. It showed that two isolated strains had a better feature in producing yeast polysaccharide, and had a potential to be excellent strains. By adding 5% of the two strains seed solution to malt extract medium respectively, and processing liquid aerobic fermentation at 30°C, 200 r/min for 24 h. Then added 10% of the two kinds of fermented liquid into solid medium composed of soybean meal, bran and flour, contained 60% water at the ratio of 1:1, at 30°C for 48 h, and dry naturally. The composited YC had live bacteria number 4×106CFU/g, malic acid 0.24 mg/g, tartaric acid 1.34 mg/g, citric acid 2.58 mg/g, and acetic acid 8.87 mg/g.3) For investigating the effect of Saccharomyces cerevisiae separated from Massa Medicata Fermentata and sourdough, Bacillus subtilis and papain, we studied the effects of newly developed composited yeast culture, Bacillus subtilis, papain, and YC plus papain on growth, fecal microbiota and nutrient digestibility of nursery pigs. A total of 225 weaned pigs(initial body weight: 15.7 ± 0.26 kg) were randomly allotted to 5 treatments and fed with 5 different diets, including basal diet(control, CT), diet supplemented with 5 g/kg YC, diet supplemented with 2×1011 CFU/kg Bacillus subtilis(BSK), diet supplemented with papain(PE) with 0.3 g/kg, and diet supplemented with YC and papain(YP). The results showed that the final body weight(BW), average daily gain(ADG) and feed to gain ratio(F/G) of YP group were significantly higher than the piglets in the CT group(P < 0.05). The final body weight in the YC group was higher than that the CT, BSK and PE groups(P > 0.05). Average daily feed intake(ADFI) was not changed by the addition of the additives in the diet, except in the YP group which was higher than the other groups. In the YP and PE groups, the diarrhea rate was decreased compared with the other groups(P < 0.05). The piglets in the YC group had the lowest diarrhea rate(P < 0.01), whereas in the BSK group the diarrhea rate of the pigs remained no change. The digestibility of the gross energy(GE) and dry matter(DM) was significantly increased in the YC, BSK, PE and YP groups compared with the CT group(P < 0.05). The piglets in the YC group showed decreased digestibility on crude protein(CP), neutral detergent fiber(NDF), calcium(Ca) and phosphorus(P). In the YP group, the digestibility of the animals increased(P > 0.05). In the feces of the animals from YC and YP groups the number of Lactobacillus was higher than those in the other groups(P < 0.05). The BSK group had the lowest Lactobacillus number(P < 0.05). In the feces of the animals from the YC and YP group, the number of Escherichia coli decreased(P < 0.05); while the ratio of Lactobacilli to E. coli was increased in the YC and YP group(P < 0.05). In conclusion, the novel YC could improve the growth performance and intestinal micro-ecology environment of the piglets. The YC and papain combination could also improve the growth performance of piglets.