Poly‐β‐Hydroxybutyrate (PHB) Improves Nursery‐Phase Pacific White Shrimp Litopenaeus vannamei Defense against Vibriosis

Abstract This study assessed the effect of poly‐β‐hydroxybutyrate ( PHB ) on the growth, survival, and disease resistance of Pacific white shrimp Litopenaeus vannamei . A 20‐d feeding test using 30‐d‐postlarval Pacific white shrimp (100 shrimp/tank) tested three different diets: 0.3 g PHB /kg diet, 0.5 g PHB /kg diet, and commercial feed containing no PHB as the control. The feeding test was followed by a 10‐d bacterial challenge test using Vibrio harveyi . After the feeding test, the highest average final body weight, specific growth rate, and total biomass (mean ± SD = 0.44 ± 0.28 g, 28.82 ± 2.08%/d, and 25.91 ± 7.19 g, respectively) were found in the 0.5 g PHB /kg diet group, while the 0.3 g PHB /kg diet showed the highest survival rate (67.00 ± 8.83%). After the Vibrio harveyi challenge test, both PHB diet treatments resulted in the same significantly higher survival rate (96.66 ± 4.71%) compared with the control treatment (70.00 ± 4.71%). The highest body weight gain during the challenge test was seen in the 0.5 g PHB /kg diet group. Total abundance of heterotrophic bacteria and Vibrio spp. was relatively similar for all treatments. Histopathological analysis showed that hepatopancreas samples from PHB ‐supplemented Pacific white shrimp showed decreasing tubular epithelial cell lesions as a result of Vibrio harveyi infection, suggesting that PHB protected the hepatopancreas of Pacific white shrimp from the destructive effect of Vibrio harveyi infection. Supplementation at 0.5 g PHB /kg significantly increased Pacific white shrimp survival and growth with or without Vibrio harveyi infection and, thus, has high potential for further use in Pacific white shrimp aquaculture.