Calibrin® -Z Increases Shrimp Survival During Early Mortality Syndrome (EMS) Challenge

Two studies conducted at the University of Arizona showed that shrimp fed Calibrin-Z had survivability of 84% when challenged to induce Early Mortality Syndrome (EMS) vs. 5% for challenged shrimp not fed the enterosorbent, write Ron Cravens, DVM, Fang Chi and San Ching, PhDs.

Background

Calibrin-Z is proven to bind fungal and bacterial toxins and reduce the effects of mycotoxicosis and certain diseases caused by bacterial toxins in poultry. Recently it was found that the cause of EMS in shrimp is due to a toxin produced in the gut by Vibrio parahaemolyticus. Therefore, it was hypothesized that adding Calibrin-Z to shrimp diets would decrease the effects of EMS in shrimp.

Experimental Procedures

Two experiments were conducted at the University of Arizona, Tucson, AZ. A total of 318 specific pathogen free (SPF) Penaeus vannamei at an average weight of 1 gram were stocked for 5 replications (2 reps in trial 1 and 3 reps in trial 2) at 20 or 22 animals per tank into 90 L aquaria.

Overall, five tanks of shrimp were designated as negative control tanks and received no EMS challenge; five tanks served as positive controls, receiving the EMS challenge, but fed a diet without Calibrin-Z; and five tanks of shrimp were fed the diet containing Calibrin-Z and challenged to induce EMS. After a 7 day pre-feeding period EMS challenged groups were fed with diets contaminated with V. parahaemolyticus multiple times (1x/day in Exp.1 and 2x/day in Exp. 2) until the ideal mortality was achieved in the positive control.

The overall survival rate is presented in Figure 1. The accumulated mortality by day is presented in Figure 2.

Water Quality

Water quality was maintained during the experiment as in Table 1.

Histopathology

The cause of the increased mortality from EMS is because of the damage the toxin(s) released by V. parahaemolyticus does to the hepatopancreas of t he sh r i mp. H i s tolog ic a l ex a m i nat ion of representative moribund or surviving shrimp was completed and is summarized in Table 2. Examples of typical histopathology of the hepatopancreas with increasing amounts of damage due to EMS are shown in Figure 3. (Lightner, GOAL 2012).

Conclusions

Challenged shrimp fed Calibrin-Z had:

• Improved Survivability – 84% vs. 5%
• Improved Histopathology – G0 vs. G3