Effect of Dietary Tryptophan on Growth, Intestinal Microbiota, and Intestinal Gene Expression in an Improved Triploid Crucian Carp

Abstract

Tryptophan (Trp) has received increasing attention in the maintenance of intestinal function. In this study, improved triploid crucian carp (ITCC) fed diets containing 6.35 g kg−1 Trp had higher average daily gain (ADG) and improved villus height (VH) and crypt depth (CD) in the intestine compared to the control group. To elucidate the potential mechanisms, we used RNA sequencing (RNA-seq) to investigate changes in the intestinal transcriptome and 16S rRNA gene sequencing to measure the intestinal microbiota in response to 6.35 g kg−1 Trp feeding in ITCC. Dietary Trp altered intestinal gene expression involved in nutrient transport and metabolism. Differentially expressed transcripts (DETs) were highly enriched in key pathways containing protein digestion and absorption and the AMPK signaling pathway. 16S rRNA sequencing showed that 6.35 g kg−1 Trp significantly increased the abundance of the genus Cetobacterium, and the Firmicutes/Bacteroidetes ratio at the phylum level (P < 0.05). In addition, bacterial richness indices (Simpson index) significantly increased (P < 0.05) community evenness in response to 6.35 g kg−1 Trp. In conclusion, appropriate dietary Trp improves the growth performance, and influences the intestinal flora of ITCC. This study might be helpful to guide the supply of dietary exogenous Trp in ITCC breeding.

Dietary Supplementation With Hydroxyproline Enhances Growth Performance, Collagen Synthesis and Muscle Quality of Carassius auratus Triploid

“…× common carp ( Cyprinus carpio L.) allotetraploid hybrids (♂) with the diploid Japanese crucian carp (♀) ( Carassius auratus cuvieri T. et S.) ( Chen et al, 2009 ). Because of its advantages of fast growth speed, strong stress tolerance and delicious flesh quality, ITCC is the preferred species of crucian carp in freshwater aquaculture in China ( Fu et al, 2021 ). Up to now, some studies have reported that Hyp can promote growth and improve muscle quality in carnivorous marine fish, whereas Hyp’s potential for the same effect on omnivorous freshwater fish remains unknown.…”

Metabolic Fate Is Defined by Amino Acid Nature in Gilthead Seabream Fed Different Diet Formulations

“…It is worth mentioning that most of the retained tryptophan (±48%) was found in the gut, which was also observed in Senegalese sole juveniles [19]. This may be due to tryptophan being the precursor of 5-hydroxytryptophan, which in turn is the precursor of serotonin, a hormone mainly synthesised in the gastrointestinal tract [11,34], or due to the beneficial effects of tryptophan in the intestinal structural integrity of fish [35].…”

Effects of chlorogenic acid on growth, metabolism, antioxidation, immunity, and intestinal flora of crucian carp (Carassius auratus)

“…Meanwhile, oral CGA also had a positive effect on the density and height of the intestinal villi of Carassius auratus. The density and height of villi in the intestine can increase the contact area between the intestine and intestinal contents, thus increasing the deposition of nutrients, Frontiers in Microbiology 08 frontiersin.org which is of great significance for improving the health of animals (Fu et al, 2021).…”