Gut microflora, gut morphometry and haemato-biochemical analyses of juvenile Clarias gariepinus fed dietary Lactobacillus plantarum and guava (Psidium guajava)

Introducing probiotics and phytobiotics into fish feed is an effective strategy to reduce production costs and improve profit margins. However, there is limited information available regarding their application in aquaculture nutrition. This research evaluated the effects of diets enriched with Lactobacillus plantarum and Psidium guajava leaf meal on gut microflora, histomorphometry, water quality, and blood indices of juvenile Clarias gariepinus (initial weight: 7.48 ± 0.2 g) over an 84-day feeding trial. At the end of a-84 day feeding trial, fish samples were taken from seven treatment groups: C-Control experiment of basal diet of 42 % crude protein level, 40LPc (40 ×10 5 ml L. plantarum per kg of feed), 60LPc (60 ×10 5 ml L. plantarum per kg of feed), 80LPc (80 ×10 5 ml L. plantarum per kg of feed), 40PGLM (40 g P. guajava per kg basal diet), 60PGLM (60 g P. guajava per kg basal diet) and 80PGLM (80 g P. guajava per kg basal diet) with three replicates. There was significant difference (P < 0.05) in the Enterobacteriaceae count between the control (4.3 ± 0.2) log 10 cfu/g and other treatment groups. There was significant difference (P < 0.05) in the total viable count between 80PGLM (4.5 ± 0.2) log 10 cfu/g and other treatment groups which included control, 80LPc (4.7 ± 0.2) log 10 cfu/g and 60PGLM (4.8 ± 0.2) log 10 cfu/g respectively. Diets containing 40PGLM showed the highest levels of Hb (hemoglobin) and RBC (red blood cell) (P < 0.05). Fish-fed diets containing 40LPc and 80 PGLM showed a significant increase in total protein (TP) and heterophils (Het) (P < 0.05). Lower AST (aspartate aminotransferase), ALP (alkaline phosphatase), and ALT (alanine aminotransferase) were also exhibited in the L. plantarum and P. guajava groups (P < 0.05). The highest villi height (93.6 ± 0.0 µm), villi width (31.5 ± 0.01 µm) and cryptal depth (30.5 ± 0.0 µm) were observed in 40LPc treatment group (P < 0.05). Increase in the proliferation of Enterobacteriaceae in C. gariepinus juveniles fed dietary L. plantarum enhanced the growth of beneficial bacteria in fish gut . According to these results, a diet containing 40 LPC is suitable for feeding C. gariepinus . • L. plantarum & P. guajava meal improved gut flora, boosting Enterobacteriaceae and helping beneficial bacteria grow. • The 40PGLM group had the highest Hb and RBC levels, indicating better overall health and stronger immunity. • The 40LPc group had the largest villi and deepest crypts, which enhanced nutrient absorption and intestinal morphology.