Ảnh hưởng của liều lượng <i>Lactobacillus acidophilus</i> lên tỷ lệ sống và biến thái của ấu trùng cua biển (<i>Scylla paramamosain</i> Estampador, 1949)

Abstract

     The effect of Lactobacillus acidophilus on survival rate and metamorphosis of mud crab larvae (Scylla paramamosain Estampador, 1949) was investigated at crustacean hatchery of Ca Mau community college. This experiment aimed to identify the suitable concentration of Lactobacillus acidophilus used to the minimize antibiotic application, to improve the production and survival rate of mud crab rearing. The experiment in the larval rearing period from zoea-1 stage to crab-1 stage was conducted with different densities of Lactobacillus acidophilus as following 10⁴, 10⁵ and 10⁶ CFU/mL, respectively with three replicates per treatment. Larvae were reared in plastic tanks of 60 liters with the stocking density of 200 larvae/L. The results showed that the highest total bacteria was found in the treatment supplied concentration at 106 CFU/mL (4.2×10⁵ CFU/ml). It was significantly different from other treatments (p<0.05). The level of Vibrio sp was significantly lowest in the third treatment (0.21×10³ CFU/mL) (p<0.05). Metamorphic rate and the total length of zoea₅ stage in the treatment 10⁵ CFU/ml were the highest with 65.6% and 4.44 mm, respectively. The body length of crab-1 was highest (3.13 mm) in treatment 10⁵ CFU/mL and was not significantly different with other treatments (p>0.05). The survival of crab-1 was the best in the treatment 10⁶ CFU/mL (8.54%); which was not significantly different from those of the first treatment (8.12%) and second treatment (8.51%) (p>0.05). The results suggested that addition of Lactobacillus acidophilus at concentrations at 10⁵ CFU/mL could be applied to commercial production for mud-crab harchery.

Keywords: Lactobacillus acidophilus, mud crab, probiotic, Scylla paramamosain.