Authors
1
Department of Basic Science, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2
Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3
Department of Livestock, Poultry and Aquatic animal Health, Shahid Chamran University of Ahvaz, Ahvaz, Iran
10.22092/ijfs.2024.131413
Abstract
Aquaculture represents a pivotal economic sector worldwide, meeting the escalating food demands of the expanding global population. Consequently, this research aimed to assess the incidence of fatty liver in Asian sea bass (Lates calcarifer) subjected to a diet enriched with lactic acid bacteria and evaluate their survival against Streptococcus iniae infection. The present study examined 240 sea bass (109 ± 10.5 g average weight) that were randomly assigned into four treatments with three replicates (25 specimens per treatment) for 60 days. The treatments comprised the following: First treatment: fish were fed with commercial feed. Second treatment: fish were provided with feed containing 109 CFU/g of Lactobacillus plantarum bacteria. Third treatment: fish were fed with feed containing 109 CFU/g of Lactobacillus pentosus bacteria. Fourth treatment: fish were provided with feed having 109 CFU/g of L. pentosus bacteria combined with L. plantarum in equal proportions. At the end of the experiment, the growth performance, the survival rate against the pathogenic bacteria S. iniae and the amount of fatty liver were evaluated. The findings disclosed enhanced growth indicators in the second treatment (strain 140) during the initial 30 days. Furthermore, statistically significant disparities were noted in the third treatment (2P) concerning PER, SGR, WG, RGR, and DWG during the subsequent 30-day period (P<0.05). Liver pathology examination demonstrated that most treatments resulted in the development of fatty liver. However, the third treatment (L. pentosus) exhibited the lowest incidence of fatty liver when endogenous probiotics were incorporated into the diet. Post-challenge with S. iniae, the mortality rate in the probiotic treatments L. pentosus (P2) and L. plantarum (140) significantly surpassed that of the control group (P<0.05). The findings underscore the absence of synergistic interactions between the two experimental probiotics on the 60th day, as the combined group displayed diminished growth performance compared to the individual groups. Moreover, the use of L. plantarum and L. pentosus bacteria, particularly the latter, has been shown to significantly improve several growth indicators, as well as the food conversion ratio. Consequently, these probiotics are recommended as dietary supplements for Asian sea bass.
Keywords
)