การคัดแยกและการประเมินคุณลักษณะของแบคทีเรียผลิตกรดแลคติกจากอาหารผสมครบส่วนแบบหมักเพื่อผลิตอาหารสำหรับโคนม

Abstract

The objective of this study weretoscreenand characterizeof lactic acid bacteria (LAB) from ensiled total mixed ration (eTMR), optimized level of LAB inoculation and effect of LAB inoculation in eTMR on milk production. The study was divided into three experiments. The first experiment werescreening, characterization, and selection of LAB from eTMR. One-hundred twenty colony were randomly screened from eTMR at 3, 7, 14, 21 days of ensiling time for determination including by morphology, pH tolerant, heat tolerant, lactic and acetic acid production. DNA from colony were extracted and identified. Then, LAB was measured growth rate. The result shown that 84 colony can drop pH lower than 4.2. Thirty-four colony can grow at 45o C. Fifteen highest colony which produce high lactic acid were selected for identification. The result show that LAB is 1) Lactobacillus plantarum, 2) Pediococcus pentosaceus, 3) L. paracasei and 4) P. acidilactici. Four LABs were measured growth rate. L. paracasei showed high potential for inoculation in eTMR. The second experiment was optimizationlevel of L. paracasei in eTMR. The treatments were divided into 5 treatments: 1) eTMR (Control), 2) eTMR+ L. paracasei 104 CFU/g, 3) eTMR+ L. paracasei 105 CFU/g, 4) eTMR+L. paracasei 106 CFU/g and 5) eTMR+L. paracasei 107 CFU/g. Sample were collected at 0, 3, 5, 7, 14, 21, and 28 day of ensiling times for analysis of fermentation quality, chemical compositions, degradability by in vitro gas production technique and in situ nylon bag technique. The result shown that high level of L. paracasei inoculant enhances fermentation quality of eTMR by reducing pH, NH3 -N and butyric acid but lactic acid decreased. High level of L. paracasei increased organic matter, acid detergent fiber, hemicellulose, and cellulose. However, crude protein and acid detergent lignin were decreased. L. paracasei inoculation cause gas production at 2h and 4h from 5day sample and 8, 12, 24, 48, 72 and 96h from 3day sample were significant differences. Amount of VFA at 24h incubation and degradability by in situ nylon bag technique were not significant. Consideration from above data shown 106 CFU/g was optimal level for inoculation in eTMR. The third experiment was study effect of L. paracasei inoculation in eTMR on feed intake and milk production. Treatment was divided into 2 treatments: 1) eTMR (Control) and 2) eTMR+ L. paracasei 106 CFU/g. Eighteen Thai Frisian cattle were fed eTMR for 45day. The sample of eTMR were collected from 21days of ensiling time for analysis of fermentation quality and chemical compositions. Feed intake and milk production were record every day. Milk samples were collected at 7, 14, 21, 28, 35 and 45days of experiment for analysis of milk compositions. There was not significant differeces between treatment for fermentation quality. Ether extract, acid detergent fiber and acid detergent lignin in LAB were higher than control. Feed intake in cows fed LAB was higher than control at 45 days. Cows fed LAB higher milk fat 7 than control at 21 days. Total solid from LAB higher than control at 21 days. Moreover, cows fed LAB was higher lactose from milk than control at 14 and 45days. In conclusion, L. paracasei inoculation in eTMR enhance fermentation quality and reduce loss of nutrient from ensiling process while not effect on degradability in rumen. Furthermore, L. paracasei inoculation increase feed intake and improve milk compositions.