The Effect of a Total Fishmeal Replacement by Arthrospira platensis on the Microbiome of African Catfish (Clarias gariepinus)

Abstract

An increasing number of fishmeal supplements are becoming the focus of aquaculture research, with a special emphasis on microalgae/cyanobacteria such as spirulina being considered as sustainable alternatives. New feed ingredients can have a far-reaching impact on the intestinal microbiome and therefore play an important role in the development and the health of fish. However, the influence of these alternatives on the microbiome is largely unknown. We undertook a 10 weeks feeding experiment on 120 African catfish with an initial body weight of 50.1 ± 2.95 g. To understand the effect of the spirulina supplementation, two isoenergetic experimental diets were formulated, containing either fishmeal or spirulina as a protein source. The 16S rRNA sequencing was used to analyze the intestinal bacteria microbiota. Results show that the observed richness indicated no significant statistical difference, but Chao1, ACE, Shannon, and Simpson indices indicate a possible increase in bacterial richness for the spirulina diet. The most abundant bacteria in both experimental groups were Fusobacteriia with the only taxa from the genus Cetobacterium. The bacterium from genus Romboutsia was more likely to be found in the microbiome of fish fed the fishmeal diet. In spirulina-fed fish, the genera Plesiomonas and Bacteroides were the most dominant microbes observed. Even though some genera were more abundant in the spirulina group, the overall microbial community structure was not affected by diets.

Functional Properties of Protein Hydrolysates on Growth, Digestive Enzyme Activities, Protein Metabolism, and Intestinal Health of Larval Largemouth Bass (Micropterus salmoides)

“…However, dietary protein hydrolysates supplementation significantly reduced the diversity of the intestine microbial community, which was in line with previous studies in largemouth bass and gilthead seabream ( 94 ; 95 ). Previous studies have revealed that Plesiomonas is a normal inhabitant of the fish gut ( 96 ), and this genus was also the most dominant microbes observed in African Catfish ( 97 ). The antimicrobial effect of Plesiomonas has been well clarified ( 98 ), and therefore, the decreased inflammatory response of larvae in the PH100 group may have been also partly due to the increased relative abundance of Plesiomonas .…”

Growth performance and nutritional composition of Clarias gariepinus in flood-and-drain aquaponics coupled with three species of leafy vegetable

“…Studies have reported better feed conversion efficiency in Nile tilapia raised in aquaponics than in those raised in conventional fishponds (Amin et al, 2021; Shaw et al, 2022; Strand et al, 2007). An important observation in the aquaponic fish tank was the presence of slimy cyanobacteria (Figure 5), which increased with time and has been reported to significantly contribute to more than 10% of fish protein intake and affect their gut microbiome(Rosenau et al, 2021). Changes in the gut microbiome composition have profound effects on the physiological and molecular functions of C. gariepinus (Adejonwo et al, 2020).…”

Spirulina as Animal Feed: Opportunities and Challenges

“…Overall, the digestibility for both diets was high, but the feed conversion ratio was increased for spirulina-fed rainbow trout and brook trout and resulted in significantly lower growth rates in all species. A subsequent investigation of the intestinal microbiome in African catfish, using 16S rRNA sequencing, found only slight changes for some bacterial genus, but the overall microbial community structure was not affected by spirulina-diet [ 26 ].…”