Effect of dietary supplementation of Lactiplantibacillus plantarum probiotics as functional feed additive in Pacific white shrimp (Peneaus vannamei)

Abstract

The current study aimed to investigate Lactiplantibacillus plantarum as candidate probiotic and dead bacteria functional aquafeed additives in P. vannamei. The 45-day feeding experiment was carried out in juvenile whiteleg shrimp, P. vannamei. Two hundred and seventy shrimps were randomly distributed into nine tanks with 30 juvenile shrimps (initial body weight 4.43 ± 0.045 g) constituting three replicates per treatment. Water temperature was maintained at 26–29 °C. Three experimental diets were formulated, viz. basal diet with live L. plantarum 10¹¹ CFU Kg⁻¹ of feed (LLP); basal diet with L. plantarum dead bacteria (DLP); and control basal diet (CON). The animals were fed to satiation and the feed was offered at 6% of the body weight. The diet contains 364 g/kg crude protein and 15.79 MJ/kg energy level. It was found that the group fed with LLP showed higher (17.03 ± 0.42 g) final weight, weight gain, SGR, PER, and survival than DLP and CON, though statistically not significant. However, the PPV was significantly (P < 0.05) higher in the LLP-fed group. Significantly (P < 0.05) higher total haemocyte count; small and large nongranular haemocyte; and small and large granular haemocyte, as well as the percentage occurrence of these cells, were observed in LLP. Further, prophenol oxidase enzyme was significantly (P < 0.05) high in LLP and DLP. The immune-related gene hsp 70 was significantly expressed higher (P < 0.05) in LLP and DLP. The LLP group recorded significantly (P < 0.05) higher amylase (1.80 ± 0.36 U mg⁻¹) and leucine aminopeptidase (0.78 ± 0.152 U mg⁻¹) hepatopancreatic digestive enzyme activity. Midgut depicted significantly (P < 0.05) high crypt depth (23.68 µm ± 8.20), villi height (59.53 µm ± 10.42), and muscular layer thickness (91.92 µm ± 13.98) in LLP. Rhodobacteraceae (37.69%) and Flavobacteriaceae (15.74%) were beneficial core microbiome bacterial signatures observed predominantly in LLP. In challenge studies with Vibrio campbellii, the LLP group recorded significantly (P < 0.05) lower cumulative mortality (30%) and significantly (P < 0.05) upregulated prophenol oxidase, super oxide dismutase, and heat shock protein immune gene expression. The results of the current study infer that dietary supplement of L. plantarum at 3% would act as a functional feed additive in the diet of P. vannamei.