World Aquaculture December 2018

WWW.WA S.ORG • WORLD AQUACULTURE • DECEMBER 2018 47 ( C O N T I N U E D O N P A G E 4 8 ) Vibrio were found in pond water and shrimp tail muscle. The greatest Vibrio concentrations in pond water were observed in early August at all locations and regardless of treatment, possibly due to high rates of organic loading from feed. There was a trend towards decreased levels of total vibrios in probiotic-treated ponds at GPA and GAS, but levels were not significantly different (Fig. 10). The proportion of pathogenic vibrios (green shade) was lower in probiotic-treated ponds at GAS and GPA but not at FS (Fig. 11). In contrast, shrimp collected from probiotic-treated ponds had similar to or greater concentrations of total vibrios than shrimp in control ponds at GAS and GPA (Fig. 12). Similar to what was observed with pond water vibrios, shrimp tissue examined in August had higher levels of total vibrios than in other months at all farms. There were no detectable pathological patterns observed FIGURE 13. Photos of shrimp hepatopancreas (HP) comparing normal to damaged tissue (granulomas, Vibrio and vermiforms). TOP to BOTTOM: Normal HP, Granulomas and tissue sloughing in HP, Vibrio infection of HP, Vermiform in HP FIGURE 12. Concentrations of Vibrio in shrimp tail meat sampled from ponds with or without probiotics on three farms over time ponds including Gulf American Shrimp (a), Greene Prairie Aquafarm (b) and Forkland Springs (c). a. b. c.