Cow＇s milk constitutes a significant food for babies when mother＇s milk is insufficient. The purpose of this work is to offer a fermented milk, potentially hypoallergenic, using selected Lactobaeillus acidophilus an...Cow＇s milk constitutes a significant food for babies when mother＇s milk is insufficient. The purpose of this work is to offer a fermented milk, potentially hypoallergenic, using selected Lactobaeillus acidophilus and Bifidobacteria sp. for their proteolytic activities. The fermentation is evaluated by the rate of lactic acid production and by the bacterial enumeration at 45 ℃. The rate of acidification obtained by mixed cultures （La ＋ B. longum, 63.8 ± 3.5 °D） and （La ＋ B. breve, 43.4 ± 1.67 °D） compared with the control （milk） （18.6 ± 1.31 °D）. The result of the best hydrolysis was obtained by （La＋ B. longum） （154.88 ± 30.33 ug/mg） which corresponded to a better release of the a-NH2 functions （103.32 ± 12.81 umoles/mg） compared with control （307.2 ± 11.54 ug/mg and 10.25 ± 0.44 umoles/mg ）. The best synergy was obtained by （La ＋ B. bifidum） （13 × 10^6 cfu/mL and 60 × 10^6 cfu/mL） and reached 95 × 10^10 cfu/mL and 119 × 10^10 cfu/mg at the end. The electrophoresis of fermented milk revealed the presence of soluble proteins （a-Lactalbumin and β-Lactoglobulin）. The Enzyme Linked Immtmo Sorbent Assay showed the results of residual antigenic activities of β-Lg （1.4 ± 0.23 ug/mg）, a-La （0.012 ± 0.004 ug/mg） and bovin serum albumin （0.014 ± 0.005 ug/mg）by the associations （La ＋ B. longum）, （La ＋ B. bifidum） and （La ＋ B. bifidum） compared with the control （14.43 ± 5.91 ug/mg, 0.183 ± 0.062 gg/mg, 0.05 ± 0.008 ug/mg） respectively. Lactic fermentation reduced to a significant antigenic reactivity of principal whey milk proteins.展开更多
The objective was to evaluate effects of rumen-protected methionine （RP-Met） supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty-four multiparous （2.2 - 0.4...The objective was to evaluate effects of rumen-protected methionine （RP-Met） supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty-four multiparous （2.2 - 0.40 parity） Holstein dairy cows, averaged 620 ± 12.3 kg of BW, 68 ± 2.5 day in milk and daily milk production averaged 26.0 ±0.3 kg/cow were used in a replicated 4 × 4 Latin square experiment. The treatments were： control （without RP-Met）, LRP-Met, MRP-Met and HRP-Met with 20, 40 and 60 g RP-Met per cow per day, respectively. RP-Met was hand-mixed into the top one-third of the daily ration. Experimental periods were 30 days with 15 d of adaptation and 15 d of sampling. Dry matter （DM） intake and milk yields were not affected （P 〉 0.05） with increasing RP-Met supplementation. Yields of 4%FCM, ECM, milk fat and milk protein were higher （P 〈 0.03） for RP-Met supplementation than control and were quadratically （P 〈 0.05） changed due to the higher percentage of milk fat and protein for RP-Met supplementation than control （P 〈 0.03）. Ruminal pH tended to be lower （P = 0.071） for RP-Met supplementation than control, whereas total VFA concentration tended to be higher （P = 0.086） for RP-Met supplementation than control. Ratio of acetate to propionate decreased linearly （P = 0.001） from 4.01 to 3.57 as RP-Met supplementation increased due to the increase in propionate production. Digestibilities of DM, OM, CP, NDF and ADF in the total tract were higher （P 〈 0.05） for RP-Met supplementation than control and were quadratically （P 〈 0.05） increased with increasing RP-Met supplementation. Plasma concentrations of glucose not affected （P 〉 0.05） with RP-Met supplementation, Plasma concentrations of non-esterified fatty acids （NEFA） were significantly lower （P = 0.017） for RP-Met supplementation than control and were linearly （P = 0.011） changed. Plasma concentrations of beta-hydroxybutyrate tended to be lower （P = 0.068） for RP-Met supplementation than control and were linearly （P = 0.001） changed. The present results indicate that supplementation of diet with RP-Met improved the content of milk fat and protein, rumen fermentation and feed digestion, decreased plasma concentrations of NEFA. It was suggested that the RP-Met stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum RP-Met dose was about 25 g RP-Met per cow per day.展开更多
文摘Cow＇s milk constitutes a significant food for babies when mother＇s milk is insufficient. The purpose of this work is to offer a fermented milk, potentially hypoallergenic, using selected Lactobaeillus acidophilus and Bifidobacteria sp. for their proteolytic activities. The fermentation is evaluated by the rate of lactic acid production and by the bacterial enumeration at 45 ℃. The rate of acidification obtained by mixed cultures （La ＋ B. longum, 63.8 ± 3.5 °D） and （La ＋ B. breve, 43.4 ± 1.67 °D） compared with the control （milk） （18.6 ± 1.31 °D）. The result of the best hydrolysis was obtained by （La＋ B. longum） （154.88 ± 30.33 ug/mg） which corresponded to a better release of the a-NH2 functions （103.32 ± 12.81 umoles/mg） compared with control （307.2 ± 11.54 ug/mg and 10.25 ± 0.44 umoles/mg ）. The best synergy was obtained by （La ＋ B. bifidum） （13 × 10^6 cfu/mL and 60 × 10^6 cfu/mL） and reached 95 × 10^10 cfu/mL and 119 × 10^10 cfu/mg at the end. The electrophoresis of fermented milk revealed the presence of soluble proteins （a-Lactalbumin and β-Lactoglobulin）. The Enzyme Linked Immtmo Sorbent Assay showed the results of residual antigenic activities of β-Lg （1.4 ± 0.23 ug/mg）, a-La （0.012 ± 0.004 ug/mg） and bovin serum albumin （0.014 ± 0.005 ug/mg）by the associations （La ＋ B. longum）, （La ＋ B. bifidum） and （La ＋ B. bifidum） compared with the control （14.43 ± 5.91 ug/mg, 0.183 ± 0.062 gg/mg, 0.05 ± 0.008 ug/mg） respectively. Lactic fermentation reduced to a significant antigenic reactivity of principal whey milk proteins.
文摘The objective was to evaluate effects of rumen-protected methionine （RP-Met） supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty-four multiparous （2.2 - 0.40 parity） Holstein dairy cows, averaged 620 ± 12.3 kg of BW, 68 ± 2.5 day in milk and daily milk production averaged 26.0 ±0.3 kg/cow were used in a replicated 4 × 4 Latin square experiment. The treatments were： control （without RP-Met）, LRP-Met, MRP-Met and HRP-Met with 20, 40 and 60 g RP-Met per cow per day, respectively. RP-Met was hand-mixed into the top one-third of the daily ration. Experimental periods were 30 days with 15 d of adaptation and 15 d of sampling. Dry matter （DM） intake and milk yields were not affected （P 〉 0.05） with increasing RP-Met supplementation. Yields of 4%FCM, ECM, milk fat and milk protein were higher （P 〈 0.03） for RP-Met supplementation than control and were quadratically （P 〈 0.05） changed due to the higher percentage of milk fat and protein for RP-Met supplementation than control （P 〈 0.03）. Ruminal pH tended to be lower （P = 0.071） for RP-Met supplementation than control, whereas total VFA concentration tended to be higher （P = 0.086） for RP-Met supplementation than control. Ratio of acetate to propionate decreased linearly （P = 0.001） from 4.01 to 3.57 as RP-Met supplementation increased due to the increase in propionate production. Digestibilities of DM, OM, CP, NDF and ADF in the total tract were higher （P 〈 0.05） for RP-Met supplementation than control and were quadratically （P 〈 0.05） increased with increasing RP-Met supplementation. Plasma concentrations of glucose not affected （P 〉 0.05） with RP-Met supplementation, Plasma concentrations of non-esterified fatty acids （NEFA） were significantly lower （P = 0.017） for RP-Met supplementation than control and were linearly （P = 0.011） changed. Plasma concentrations of beta-hydroxybutyrate tended to be lower （P = 0.068） for RP-Met supplementation than control and were linearly （P = 0.001） changed. The present results indicate that supplementation of diet with RP-Met improved the content of milk fat and protein, rumen fermentation and feed digestion, decreased plasma concentrations of NEFA. It was suggested that the RP-Met stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum RP-Met dose was about 25 g RP-Met per cow per day.
