Comparison of Different Dietary Fatty Acids Supplement on the Immune Response of Hybrid Grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) Challenged with Vibrio vulnificus

Abstract

Aquaculture has been expanding in Malaysia due to the increased demand for fish products. In addition, aquaculture faces challenges in maintaining feed suitability in support of the global growth of fish production. Therefore, improvements in diet formulation are necessary to achieve the optimal requirements and attain a desirable growth efficiency and health performance in fish. Seven weeks of study were conducted to compare the equal amounts of different fatty acids (2%) (oleic acid, stearic acid, palmitic acid, and behenic acid) on the survival, the growth, and the immune response of hybrid grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) against V. vulnificus. After six weeks of the feeding trial, fish were challenged with V. vulnificus for 30 min before continuing on the same feeding regime for the next seven days (post-bacterial challenge). Fish supplemented with dietary oleic acid showed significantly (p < 0.05) enhanced immune responses, i.e., lysozyme, respiratory burst, and phagocytic activities compared to the control diet group for both pre-and post-bacterial challenges. Following the Vibrio challenge, no significant effects of supplemented fatty acid diets on survival rate were observed, although dietary oleic acid demonstrated the highest 63.3% survival rate compared to only 43.3% of the control diet group. In addition, there were no significant effects (p > 0.05) on specific growth rate (SGR), white blood cell (WBC), and red blood cell (RBC) counts among all experimental diets. The results from this study suggest that among the tested dietary fatty acids, the oleic acid diet showed promising results in the form of elevated immune responses and increased disease resistance of the hybrid grouper fingerlings challenged with V. vulnificus.

Oleic acid as potential immunostimulant in metabolism pathways of hybrid grouper fingerlings (Epinephelus fuscoguttatus × Epinephelus lanceolatus) infected with Vibrio vulnificus

“…From our previous study, key metabolites from the fatty acid group namely oleic acid, stearic acid, palmitic acid, behenic acid, palmitoleic acid, cis-erucic acid, and 8,11-eicosadienoic acid, are abundant in grouper that survived the V. vulnificus infection 21 . This finding is consistent with the study by Natnan et al 22 , who showed that the exogenous of oleic acid, palmitic acid, stearic acid and behenic acid in the feed formulation can increase the immune response while simultaneously helping to improve survival 22 .…”

Effect of temperature on fatty acid composition in the Nile tilapia (Oreochromis niloticus): A temperature dependent nutritive lipid profile

“…Among the SFAs, palmitic acid (16:00) was recorded in the highest proportion. It is a key metabolite of the fish, so its concentration is independent of fish diet (Chang et al, 2021; Hashim et al, 2021; Natnan et al, 2022). In the present study, the variations in palmitic acid content are affected by the temperature variations in different seasons.…”

“…Similar results were found in perch ( Perca fluviatilis ) tissue by Sushchik et al (2017). The second most abundant SFA was stearic acid (18:0), it is also metabolic product of the fish (Natnan et al, 2022) and is temperature dependent (Kaçar et al, 2016; Natnan et al, 2022; Sushchik et al, 2017).…”

“…Among MUFAs, the high contents of oleic acid (18:1 n‐9 cis) and palmitoleic acid (16:01) are considered the most important components of fish oil. The production of these acids depends on the metabolic rate, which in turn is temperature dependent (Citil et al, 2014; Ding et al, 2020; Guderley, 2004; Kalyoncu et al, 2010; Natnan et al, 2022). The present study showed that both oleic acid and palmitoleic acid were highest in January and lowest in June.…”

Transcriptomic responses to RGNNV and Vibrio alginolyticus infection in the spleen of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀)

“…The hybrid grouper ( Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus ♀) is one of the most important breed in mariculture industry of China [3] . But the studies of hybrid grouper mainly focused on nutrition [ [4] , [5] , [6] ], feed additives [7] , [8] , [9] and environmental response [ 10 , 11 ]. Few information regarding the immune response against pathogen infection except for parasite were recorded [ 12 , 13 ].…”