Effect of Probiotics on Production Performance, Bacterial State and Immune Responses of Macrobrachium Rosenbergii (De Man, 1879)

Abstract

The study has been investigated the effect of probiotics on production performance of freshwater prawn (Macrobrachium rosenbergii) in the pond complex of Khulna University from April, 2012 to May, 2013. The experiment trial was done in Shrimp Research Station, BFRI, Bagerhat. During nursery rearing stocking density was 1000 PL/m² in the first phase at Hapa for 20 days, then they were transferred into second phase in the nursery ponds at 20/m² for a further 40 days where the survivability found 84% and 77% respectively to the probiotic treated and control prawn. In grow out phase there were two treatments along with control viz. (a) without probiotics treated through out the life (control), (b) always probiotics treated at larval, nursery and grow-out phase (T1) and (c) probiotics treated only at grow-out phase (T2). Nine ponds (each 240 m²) were used to conduct the experiment. The stocking density was 2/m² for all the treatments and each treatment was triplicated. Two probiotics namely Super PS (soil probiotics) and Zymetin (feed probiotics) were used as per the labeled instruction. The average initial body weight in grow out pond was 2.83g. After 5 months rearing weight became 36.27g, 46.16g, 17.67 and 42.13g, survivival rate during harvesting was 86.66, 92.91 and 90.83% and the total production were 628.63, 857.57 and 765.33 kg/ha where PCR was 1.81, 1.40 and 1.52 in Control, T1 and T2 respectively. There was significant difference of prawn grown performance among the treatments (P<0.05). The lowest FCR, and highest production performance was found where the T1 and T2 were treated from larval, nursery and grow-out phases. The important water quality parameters were measured and found within the cultivable range. The microbial study revealed lowest growth of harmful bacteria, the amount of total coliforms in prawn gut was at least 1.8 MPN/g, 0.8 MPN/g and 1.4 MPN/g in control, T1 and T2 respectively, but no faecal coliform, Vibrio and Salmonella found in any treatment. The growth of beneficial bacteria, Streptococcus faecalis was found 0.35×10⁴, 2.93×10⁴ and 2.88×10⁴ CFU/g in Control, T1 and T2 respectively. The total haemocyte count (THC) was 21×10⁴, 22.05×10⁴ and 21.81×10⁴ cells/cubic millimeter in Control, T1 and T2 respectively. The differential haemocyte count (DHC) indicates little differences among the treatments, higher differences between the sexes and highest differences in case of seasonal changes. As a developing country probiotics based prawn culture could enhance production and produce quality prawn that would expand export market. Thus prawn culture will keep role on earning foreign currency and uplift the livelihood of the poor farmers and all concerning the prawn industry.