Increased resistance to thermal shock in Pacific white shrimp fed on green algae and its effect in conjunction with probiotics

This study aimed to evaluate the in vivo effect of the macroalgae Ulva ohnoi, alone and combined with
the probiotic Lactobacillus plantarum, on zootechnical, immunological, and microbiological performance,
thermal resistance and survival of Litopenaeus vannamei challenged with Vibrio parahaemolyticus. The
shrimp were fed four diets: control, seaweed, probiotic, and a combination of seaweed + probiotic. After six
weeks, a significant difference between the control and probiotic, and the control and seaweed treatments was
demonstrated in shrimp challenged with Vibrio, with the highest percentage of mortality being observed in
the group fed only with seaweed, followed by probiotic, seaweed + probiotic, and control. The control and
seaweed treatment groups also showed a significant difference in resistance to thermal shock. The animals
treated with the control diet had the highest mortality rate, followed by seaweed + probiotic, probiotic, and
seaweed. The zootechnical, immunological, and microbiological parameters did not differ significantly among
treatments. In conclusion, the use of U. ohnoi alone demonstrated a positive effect on thermal shock resistance
but did not demonstrate protection against infection caused by V. parahaemolyticus. On the other hand, its
combined use with L. plantarum in the diets did not have a positive effect on the parameters evaluated.