Effects Of Modified Montmorillonite On Adsorption Of Trypsin Inhibitor And On Digestive Function Of Post-weaning Pigs

In order to determine the effects of modified montmorillonite (MM) on adsorption oftrypsin inhibitor (TI) and on growth performance, nutrient utilization and intestinemorphology of post-weaning pigs, this study was divided into the following parts:The first trial was conducted to investigate whether MM can adsorb TI in vitro.0.5h,2h,4h,8h and16h of solution time gradient was set at the temperature gradient20℃(roomtemperature),30℃,40℃and50℃, respectively. Raw soybean was dissoluted in gastric acid,intestine juice and the buffer to detect TI by Chinese Standard respectively to set a suitablesolute condition. Five different soy products were selected as experimental materials: rawsoybean (Northeast soybean), low-protein soybean meal (CP=43%), high-protein soybeanmeal (CP=46%), soy protein concentrate (SPC) and soy protein isolate (SPI). Then MM with5different gradients (0,0.05%,0.10%,0.15%,0.20%and0.25%) were added in each soyproducts respectively to determine TI content in soy-MM mixture. The results showed thatsolvents hardly affectted TI (P>0.05). The suitable temperature and time was20℃and2h,respectively. MM could decrease TI with the most effective concentration of0.10%.Metabolic trial. This experiment was conducted to investigate effects on the growthperformance, nutrient utilization, intestinal morphology and serum biochemical indicators ofpost-weaning pigs treated by2sources of soy protein diets supplemented with MM. A total of24healthy post-weaning pigs (Landrace×Large Yorkshire×Duroc) with an average bodyweight (BW) of9.95±0.95kg at the average age of30±2d were used in the study. Pigs wererandomly allocated into4treatments with6repeats a treatment. The experimental wasdesigned as a2×2factorial model, and the4treatments were as follows, respectively:treatment1was supplemented with SPI, treatment2was supplemented with SPI+0.50%MM,treatment3was supplemented with soybean, treatment4was supplemented withsoybean+0.50%MM. Samples were taken at a5-day-interval over the total20d period.Results showed that diets adding MM had a better diarrhea rate than before (P <0.05). Serumurea nitrogen of piglets fed soybean meal was significantly higher than that of piglets fed SPI (P <0.05). The average daily feed intake, villus height (VH) in anterior segments ofduodenum and jejunum and number of E.coli were better in SPI+MM group than SPI group(P <0.05). MM could also increase length of jejunum and large intestine and weight of largeintestine in the SBM groups (P <0.05).Feeding trial. A total of120healthy post-weaning pigs (Landrace×Large Yorkshire×Duroc) at the age of30±2d with an average BW of7.89±0.98kg were used in the study.This experiment was conducted to determine the effect of MM on growth performance, fecalammonia nitrogen and serum biochemical indicators of pigs in large group feedingenvironment.120pigs were randomly allocated into2treatments with6repeats a treatment.The test was divided into two phases as follows: phase Ⅰ (1d-14d), treatment1was controlgroup fed with basal diet A, treatment2was test group fed with basal diet A+0.2%MM;phase Ⅱ (15d-35d), treatment1was fed with basal diet B, treatment2was fed with basaldiet B+0.2%MM. The results indicated that MM can significantly icrease globulin and reduceserum urea nitrogen levels (P <0.05). Therefore, MM may improve immunity and proteinutilization of piglets and decontaminate the environment.In conclusion, time and temperature of dissolution could affect TI measurements. MMcould adsorb TI from soybean product. Adding MM to diets with soybean protein sourcescould ease diarrhea of post-weaning pigs, improve the development of intestine andcomposition of microbial flora, increase protein utilization and reduce the production anddischarge of ammonia nitrogen. Immunity could also be improved to some degree.