Effect of probiotic bacteria on the growth of other potentially beneficial bacteria in the gut of Macrobrachium rosenbergii

Abstract

The present study was conducted to evaluate the effect of dietary supplementation of

different probiotics on the gut microbiota of Macrobrachiumn rosenbergii. The experiment

also aimed to see whether the inoculation of dietary bacteria does flourish the amount of

other probiotic bacteria in the gut or not? Three potential probiotic's bacteria namely Bacillus

spp., Lactobacillus spp., and Clostridium spp. were selected for inoculation and challenged

against Vibrio parahaemolyticus. The research was designed with 8 treatments viz. the only

Bacillus as T1, Bacillus + Vibrio as T2, Lactobacillus as T3, Lactobacillus + Vibrio as T4,

Clostridium as T5, Clostridium + Vibrio as T6, and two control as Negative control (Cn, no

Vibrio), positive control (Cv, only Vibrio). The total inoculation period was 15 days in the

laboratory tank-rearing condition. The composition of Bacillus in Cn and Cv ware 8.11±0.07

and 7.98±0.08 Log (CFU/g), whereas T1 and T2 showed higher Bacillus amount as

10.20±0.08 and 9.883±0.05 Log (CFU/g) respectively compare to Cn and Cv. Bacillus also

flourished with Lactobacillus concentration in both T1 (7.18±0.07) and T2 (7.054±0.03)

associate to Cn and Cv value respectively as 5.08±0.10 and 5.20±0.02 Log (CFU/g).

Similarly, Bacillus treated groups have higher Clostridium bacterial load (T1=6.12±0.18 Log

(CFU/g), T2= 6.234±0.09 Log (CFU/g) than Cn (4.11±0.05) and Cv (4.36±0.13 Log

(CFU/g). In term of Lactobacillus application, the concentration of Bacillus was increased to

8.471±0.13 and 7.32±0.06 Log(CFU/g); and Clostridium increased to 3.72±0.27 and

4.53±0.20 Log(CFU/g) successively in T3 and T4 compared to Cn and Cv. In case of

Clostridium inoculation, Bacillus load increased to 9.21±0.06 and 8.91±0.04 Log (CFU/g)

whereas, Lactobacillus increased to 7.88±0.18 Log (CFU/g) and 7.273±0.17 Log(CFU/g)

respectively in T5 and T6. Throughout the experiment, it was observed that probiotic bacteria

had significantly increased the total number of bacterial load in the prawn gut, where Bacillus

and Clostridium inoculated tanks represented legendary flourishment with other beneficial

native bacteria in the gut of Macrobrachium rosenbergii

• Supervision