Study On The Strain Breeding Of Fermented Rapeseed Meal And Its Industrialized Application

Rapeseed meal resource is very abundant. It is an important source of vegetable protein feed in China. However, rapeseed meal has plenty of anti-nutritional factors, which greatly influenced the use of animal fodder. Removal of anti-nutritional factors by microbiological fermentation is a more commonly method in rapeseed meal. There are many advantages of microbiological fermentation method, such as obvious degradation effect, mild conditions, simple process, small loss of dry matter, and so on. Fermentation can make the taste of rapeseed meal better, improves the flavor and nutrition utilization of rapeseed meal. In this study, experiment on the breeding by N~+ion implantation and cultivation of the rapeseed meal glucosinolates degrading strain Aspergillus niger, and optimizes lactic acid bacteria industrial culture medium of fermented rapeseed meal. Then, the experiment studies on the effect of storage conditions and period on forage quality of fermented rapeseed meal. Finally, using an animal experiment evaluate the fermented rapeseed meal’s application effect on finishin pigs.Experiment1: Study on the breeding by N~+ion implantation and cultivation of the rapeseed meal glucosinolates degrading Strain. To obtain an efficient rapeseed meal glucosinolates degrading strain by N~+ion implantation. Aspergillus niger CICC-2238was original probiotic, which was implanted by N~+ion with dose of60×2.5×1013ions/cm2under implantation energy for2times and a high-yield mutant strain H-109was obtained. Compared with the original strain, the glucosinolate degradation rate of mutant strains was enhanced from28.95％to49.88％. The result showed that N~+ion implantation mutation was a successful way of breeding rapeseed meal glucosinolates degrading strain.Experiment2: Study on the optimization lactic acid bacteria industrial culture medium of fermented rapeseed meal. To industrial production need, optimized the lactic acid bacteria medium of fermented rapeseed meal with the prices of raw materials. According to the results of single-factor test, select corn flour, soybean flour, K2HPO4, CH3COONa, and initial pH of the five factors, optimize the composed of lactic acid bacteria industrial culture medium by a L1（835） o rthogonal experiment. Results showed the optimization conditions were as follows: corn flour30g/L, soybean flour15g/L, K2HPO41.5g/L, CH3COONa3g/L, pH6.5, cultivated at37℃24h, the viable counts were5.52×l08c fu/mL. With the optimized medium for anaerobic fermentation of solid meal, the rate of glucosinolates degradation of45.68%, isothiocyanate degradation rate40.81%, oxazolidine thione degradation rate was51.94%, and compare with lactic acid bacteria MRS medium, the both of fermentation effect was not significant. The results suggested that the optimized medium could replaced MRS medium in industrial production of rapeseed meal fermentation and reduced the cost of lactic acid bacteria medium.Experiment3: The effect of storage conditions and period on forage quality of fermented rapeseed meal. Experiment by measuring the moisture, crude protein, glucosinolates, lactic acid, probiotics, isothiocyanates, oxazolidine thione content and pH value of the fermented rapeseed meal which under the different conditions, such as different water content (12%±2%in trial1,20%±2%in trial2,40%±2%in trial3and58%±2%in trial4), different retention times (15days,30days,45days,60days,75days and90days) and in the warehouse natural temperature (from summer to autumn).The results showed that with the extension of storage time, the crude protein and lactic acid content in fermented rapeseed meal of four trials in an upward trend(P>0.05), glucosinolates and probiotic content and pH values were significantly lower (P <0.05) In addition to the isothiocyanates and oxazolidine thione in the fermented rapeseed meal of trial1were no significant change (P>0.05), the other three trials were significantly lower (P <0.05).The results suggest that the fermented rapeseed meal in about12%to60%water content, which kept in90days under natural temperature didn’t affect the feed quality, and could increase the crude protein and lactic acid content of useful elements and reduced anti-nutritional factors content.Experiment4: Study on the feeding value of fermented rapeseed meal on finishing pigs. One hundred and sixty Duroc×Landrance×Yorkshire crossbred finishing pigs with an average body weight of70kg were divided into4groups with4replicates in each group and10piglets in each replicate, male: female was1:1. The4groups were as follows: control group (fed the current farm diet), group1(replaced all the soybean meal with equal proportion fermented rapeseed meal in the control group diet), group2(replaced all the soybean meal with0.96fermented rapeseed meal and0.04corn flour in the control group diet), group3(replaced the half soybean meal with equal proportion fermented rapeseed meal in the control group diet), the trial period was45days. The results showed as follows: The average daily feed intake and average daily gain of group1and group2were extremely significantly lower than the control group (P<0.01), feed conversion was extremely significantly higher than the control group (P<0.01), dressing percentage was significantly lower than the control group (P <0.05), the average daily feed intake, average daily gain and feed conversion of group3were not significant difference compared with the control group (P>0.05), and the dressing percentage improved by0.64percentage points compared with the control group (P>0.05) The skin thickness, back fat thickness, drip loss, meat color score, and shear stress of three groups were not significantly different compared with the control group (P>0.05) The eye muscle area of group3was not significantly different compared with the control group, and the eye muscle area of group1and group2were decreased by9.53cm2(P <0.05) and3.98cm2compared with the control group (P>0.05).These results showed that fermented rapeseed meal could be used to replace about10percent soybean meal in the diet for finishing pigs, without adverse effects on the performance, slaughter performance and pork quality, could be improved the dressing percentage and meat tenderness, and reduced the drip loss.