Effects of Dietary Protein Level on the Gut Microbiome and Nutrient Metabolism in Tilapia (Oreochromis niloticus)

Abstract

Dietary protein is one of the most important nutritional factors in aquaculture. The aim of this study was to examine the effects of dietary protein levels on the gut microbiome and the liver and serum levels of metabolites in tilapia. Tilapia were fed a diet with a low (20%), moderate (30%), or high (40%) content of crude protein, and the homeostasis of the gut microbiome and metabolic profile of the liver and serum were analyzed. The results showed no significant differences in the diversity and richness of the gut microbiome among the groups; however, there were differences in the microbial composition of the gut. The metabolome analysis of liver samples revealed a difference in the glucose level among the groups, with the highest glucose level in fish fed a high protein diet. In addition, there were significant differences in the levels of tyrosine, guanosine, and inosine among the metabolome analysis of serum samples of these groups. In summary, diets with different protein levels could affect the composition of gut microbiota and the dynamic balance of microbial communities. Dietary protein content can also affect glycolysis and amino acid metabolism in tilapia.

Sources of protein diet differentially stimulate the gut and water microbiota under freshwater crayfish, marron (Cherax cainii, Austin 2002) culture

“…Hence, the microbial differences in the gut and water may be primarily generated due to the differences in dietary treatments. The effects of various protein diets have been investigated on fish gut microbial communities (Gajardo et al ., 2017; Egerton et al ., 2020; Pérez‐Pascual et al ., 2021; Yang et al ., 2021); however, this is the first in‐depth study wherein impacts of different protein diets from plant sources (SOY and LNP), and processed animal protein sources (PBP, BSFL and TH) on the gut and water microbial communities, in correlations to growth performances of marron, a freshwater crayfish native to Western Australia were investigated. The microbial communities in the gut and water were distinctly different while Aeromonas was the only bacteria found with a read abundance of >5% in all samples.…”

Substrate preferences, phylogenetic and biochemical properties of proteolytic bacteria present in the digestive tract of Nile tilapia (<i>Oreochromis niloticus</i>)

“…Moreover, these three species which were recovered from tilapia intestine had also been reported to possess extracellular protease activity and other beneficial properties, and are, therefore, considered as probiotic candidates for Nile tilapia [39] , [46] , [47] . Although not frequently, but the other four genera identified in our analysis, Pseudomonas , Stenotrophomonas , Micrococcus and Providencia , have also been described among the intestinal bacteria of Nile tilapia [44] , [48] – [50] . Whatever the source of their isolation is, species of all the seven genera were reported producing extracellular protease enzymes [51] – [58] .…”

Rice protein concentrate as a fish meal substitute in Oreochromis niloticus: Effects on immune response, intestinal cytokines, Aeromonas veronii resistance, and gut microbiota composition

“…The gut microbiome (i.e., the collection of microorganisms inhabiting the gut of fish along with their overall genetic information) is closely associated with various aspects of the health and physiology of the hosts [75,76]. The properties of the gut microbiome are mainly affected by the diet and feed composition [30,31]. In this study, the different levels of rice proteins in the feed decreased the gut microbial diversity.…”

“…The gut microbiome, which plays a key role in maintaining the health status and enhancing the immune system response and digestion in fish, also must be considered [28,29]. The diet and feed composition are important determinants of the composition of the microbiome [30,31].…”