Effect of Dietary Organic Acids and Astaxanthin on Growth, Survival and Tolerance to Vibrio Infection in Pacific White Shrimp (Litopenaeus vannamei)

Abstract

A study on the effect of organic acid (AMASIL NA, Formic acid 94%) and astaxanthin (Lucantin Pink CWD, Astaxanthin 10%) on growth and survival of Pacific white shrimp (Litopenaeus vannamei) was carried out under laboratory conditions. Tests with six treatments (four replicates/treatment) were conducted. Postlarvae (PL12) were stocked in 500-L fiberglass tanks (salinity 25 ppt, temperature 29±l°C) at a density of 75 PL/tank. Shrimp were fed four times daily with pelleted feed containing AMASIL NA at 0.3 %, AMASIL NA at 0.6 %, Lucantin Pink CWD 50 ppm, AMASIL NA at 0.3 % + Lucantin Pink CWD 50 ppm, AMASIL NA at 0.6% + Lucantin Pink CWD 50 ppm and the control group (without AMASIL NA and Lucantin Pink CWD). After 60 days of dietary administration, shrimp fed with Lucantin Pink CWD 50 ppm had an average body weight of 4.45±0.45 g, which was higher than those of shrimp fed with AMASIL NA at 0.3 % + Lucantin Pink CWD 50 ppm (4.38±0.37g), AMASIL NA at 0.6 % + Lucantin Pink CWD 50 ppm (4.05±0.2lg) and the control group (4.18±0.05g). There was a statistical difference between these groups and those fed withAMASIL NA at 0.3 % (3.68±0.49g) and AMASIL NA at 0.6 % (3.88±0.22g). Shrimp fed with AMASIL NA at 0.6 % + Lucantin Pink CWD 50 ppm had the highest survival rate of 82.33±8.32 %, followed by those fed withAMASIL NAat 0.3% + Lucantin Pink CWD 50 ppm (78.67±7.77%), Lucantin Pink CWD 50 ppm (78.33±9.26%), AMASIL NA at 0.3 % (72.33±9.94%) and AMASIL NA at 0.6% (67.67±14.29%). Survival rates of these groups were significantly different from the control group (64.33±10.12%). A study of the effects ofAMASILNA and Lucantin Pink CWD on the prevention of Vibrio parahaemolyticus outbreak in rearing Pacific white shrimp was conducted under laboratory conditions. Thirty shrimp (8-9 g) from each tank in the previous experiment were randomly sampled and stocked in 12 x 500-L fiberglass tanks with four replicate tanks per treatment. V. parahaemolyticus were added into each tank to obtain final concentration of 104 CFU/ml. Each treatment group received aforementioned diets four times daily for 30 days. At the end of the trial, there were no significant differences among the average body weights of shrimp from the six experimental groups. However, shrimp fed with AMASIL NA at 0.6 % + Lucantin Pink CWD 50 ppm had the highest survival rate (67.50±3.33%), followed by those fed with AMASIL NAat 0.6% (65.00±5.77%), Lucantin Pink CWD 50 ppm (56.67±17.11%) and AMASIL NA at 0.3 % + Lucantin Pink CWD 50 ppm (54.17±5.09%). There were statistical differences between these groups and those fed with AMASIL NA at 0.3 % (45.83±16.78%) and the control group (20.00±17.32%). Shrimp fed withAMASIL NA showed significantly lower number of Vibrio spp. in the intestine compared to the group fed with Lucantin Pink CWD 50 ppm and the control group.