ABSTRACT
ABSTRACT This study aimed to evaluate 1) the in vitro effect of organic salts on the growth of the probiotic Lactobacillus plantarum and then 2) the combined use of a probiotic with organic salts on the in vitro inhibition of V. alginolyticus, A. hydrophila, E. coli, P. aeruginosa, and S. agalactiae. In vitro tests were performed with eight different organic salts, including butyrate, propionate, succinate, citrate, formate, fumarate, glutamate, and acetate, at two pH values (6.2 and 7.1) to determine their effect on the growth kinetics of L. plantarum. In addition, each organic salt was tested alone and in combination with L. plantarum to evaluate the inhibitory effect against the pathogenic bacteria noted above in either condition. Sodium citrate and formate inhibited the growth of L. plantarum, but sodium glutamate, succinate and fumarate stimulated it. Sodium propionate, butyrate, and acetate did not affect probiotic growth at all. Inhibition against all pathogens was significantly higher in the presence of the probiotic and lower pH. Comparing all organic salts at the two pH values, butyrate, acetate, and propionate exhibited more inhibition against V. alginolyticus than the others, while propionate had higher inhibition against A. hydrophila, E. coli, P. aeruginosa, and fumarate successfully inhibited S. agalactiae. Based on these results, it can be concluded that organic salts showed better in vitro inhibition against the aquaculture pathogenic bacteria tested when combined with the probiotic L. plantarum.
ABSTRACT
Objective: To study the effects of dietary sodium propionate on cholesterol metabolism in finishing pigs. Methods: A total of 96 finishing pigs (Duroc?Landrance?Jia) were randomly alotted to four groups. The groups received the same basal corn-soybean meal diet and sodium propionate was added to the basal diet in the concentrations of 0.5、1.0、1.5 % at the expense of corn, respectively. At the end of the feeding trial, eight pigs from each treatment were slaughtered. Results: (1) Pigs supplemented with 1.0% and 1.5% sodium propionate had significantly lower serum cholesterol and low density lipoprotein cholesterol concentrations and greater ratios of high density lipoprotein/low density lipoprotein cholesterol compared to the control. Pigs supplemented with 1.5% sodium propionate had significantly lower serum very low density lipoprotein cholesterol. (2) Supplementation with 1.0% and 1.5% sodium propionate significantly decreased the cholesterol content in liver and the activity of hepatic 3-hydroxy-3-methylglutary coenzyme A (HMG-CoA) reductase. (3) Supplementation with sodium propionate had no significant effects on growth performance, colonic or serum short-chain acid concentrations, fecal cholesterol or bile acid excretion. Conclusion: Sodium propionate may decrease the activity of hepatic HMG-CoA reductase and suppress the synthesis of cholesterol.