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α-Galactosidase (EC 3.2.1.22), also known asα-D-galactoside galactohydrolase,α-galactoside galactohydrolase and melibiase, specifically hydrolyzing non-reducing endα-1,6-galactoside bond, can hydrolyze melibiose, raffinose, stachyose, verbascose oligosaccharides and heteropolysaccharides withα-galactoside bond. Current studies showed thatα-galactosidase had broad application prospects in food, medicine, feed industry and other fields.In this paper we studied the solid state expanding cultivation techniques ofα-galactosidase, making a satisfactory prospect for industrial production of the enzyme. We also studied the enzymatic effect ofα-galactosidase on raffinose and stachyose, and its impact on growth performance and serum biochemical indexes of piglets. The results of this paper are listed as follows:(1) In solid state expanding cultivation ofα-galactosidase, turning materials over significantly improved the enzyme activity. Theα-galactosidase activity of fermentation production with materials turned over in 48h was significantly higher than the control, 46.06% increased (P <0.05). Beacause of evaporation, the moisture content of materials decreased gradually, the enzyme activity hits to its peak at 84h.(2) We established high-performance liquid chromatography-refractive index detector method to determine the content of raffinose and stchyose in soybean meal extraction. The precision experiment, repeated experiment, and the recovery experiment showed that this method was simple, fast, reliable, and accurate on the chromatographic conditions: Waters Sugar PAK-I column, mobile phase 500mg/L EDTA-Ca, column temperature 90℃, and flow 0.25mL/min.(3) The enzymatic effects ofα-galactosidase crude extraction on soybean meal extraction was significant. That adding 40U/mLα-galactosidase to soybean meal extraction, and under the condition 40℃for 20min, the hydrolysis rate of raffinose was 15.96 %, the stachyose hydrolysis rate was 81.65%, and the reducing sugar content increased by 17.39 times. Results showed that low concentration ofα-galactosidase acting in short time can effectively degrade raffinose and stachyose.(4) Corn-soybean meal-based diets supplemented withα-galactosidase can improve the growth performance of weaned piglets and increase economic benefits. Compared to the control group, the test groups with 0.10% and 0.15%α-galactosidase, had 6.22% and 8.29% lower feed conversion, 6.38% and 8.25% higher economic efficiency, respectively (P <0.05).
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