Effects of Dietary Phospholipids on Growth Performance, Digestive Enzymes Activity and Intestinal Health of Largemouth Bass (Micropterus salmoides) Larvae

Abstract

While the beneficial roles of dietary phospholipids on health status and overall performances of fish larvae have been well demonstrated, the underlying mechanisms remain unclear. To address this gap, the present study was conducted to investigate the effects of dietary phospholipids on growth performance, intestinal development, immune response and microbiota of larval largemouth bass (Micropterus salmoides). Five isonitrogenous and isolipidic micro-diets were formulated to contain graded inclusion levels of phospholipids (1.69, 3.11, 5.23, 7.43 and 9.29%). Results showed that the supplementation of dietary phospholipids linearly improved the growth performance of largemouth bass larvae. The inclusion of dietary phospholipids increased the activity of digestive enzymes, such as lipase, trypsin and alkaline phosphatase, and promoted the expression of tight junction proteins including ZO-1, claudin-4 and claudin-5. Additionally, dietary phospholipids inclusion alleviated the accumulation of intestinal triacylglycerols, and further elevated the activity of lysozyme. Dietary phospholipids inhibited the transcription of some pro-inflammatory cytokines, including il-1β, and tnf-α, but promoted the expression of anti-inflammatory cytokines tgf-β, with these modifications being suggested to be mediated by the p38MAPK/Nf-κB pathway. The analysis of bacterial 16S rRNA V3-4 region indicated that the intestinal microbiota profile was significantly altered at the genus level with dietary phospholipids inclusion, including a decreased richness of pathogenic bacteria genera Klebsiella in larval intestine. In summary, it was showed that largemouth bass larvae have a specific requirement for dietary phospholipids, and this study provided novel insights on how dietary phospholipids supplementation contributes to improving the growth performance, digestive tract development and intestinal health.

Effects of Soybean Lecithin on Growth Performance, Intestine Morphology, and Liver Tissue Metabolism in Rock Bream (Oplegnathus fasciatus) Larvae

“…Studies have revealed the beneficial effects of PLs in diet emulsification (Koven et al, 1993), fatty acid absorption (Fontagné et al, 2000;Hadas et al, 2003), digestive enzyme activities (Gisbert et al, 2005), intestinal lipid transportation (Lin et al, 2018) and microbiota composition (Wang et al, 2021). However, no consensus has been reached about the relationship between dietary intact PLs and intestinal morphology at the fish larval stage.…”

Effects of dietary phospholipids on growth performance, fatty acid composition and lipid metabolism of early juvenile largemouth bass ( Micropterus salmoides )

“…It is suggested that the specific requirement of phospholipids in fish larvae mainly results from the low capacity of enterocytes for the biosynthesis of phospholipids idella; Chen et al, 2015), juvenile hybrid snakehead (Lin et al, 2018) and blunt snout bream (Megalobrama amblycephala; Li et al, 2015) clarified the necessity of low-level endogenous phospholipids inclusion in compound feed based on growth performance. Previous study in our laboratory has well clarified that largemouth bass larvae have a relative higher phospholipids requirement than other freshwater fish (Wang et al, 2021), which makes the hypothesis reasonable that phospholipids is essential for early juvenile largemouth bass. However, in this study, the inclusion of exogenous phospholipids did not produce any significant difference in growth performance of early juvenile largemouth bass, which was consistent with some previous studies in juvenile large yellow croaker (Feng et al, 2017), Atlantic salmon (Taylor et al, 2015) and hybrid grouper (Huang et al, 2022).…”

“…Largemouth bass (Micropterus salmoides), a freshwater carnivorous fish, has become one of the important economic farmed fish in China. Previous study in our laboratory has determined the optimal dietary phospholipids, at least 9.29%, of larval largemouth (Wang et al, 2021), which was relatively higher than other freshwater larvae (2%-5%; Tocher et al, 2008). It is unclear whether early juvenile largemouth bass has a relative higher requirement for phospholipids.…”

“…Growing evidences have confirmed larval fish possesses limited phospholipids biosynthesis capacity, make it essential to supplement exogenous phospholipids in microdiets for fish larvae (Cahu et al, 2009). Optimal dietary phospholipids inclusion commonly produces a positive effect on growth and development, survival and prevention of skeletal deformities in larval fish (Coutteau et al, 1997; Hamza et al, 2008; Huang, Xu, et al, 2021; Wang et al, 2021; Zhao et al, 2013). In general, the demands for phospholipids based on growth performance decrease significantly with the development of fish larval into early juvenile, while phospholipids requirement of juvenile seems species‐dependent (Tocher et al, 2008).…”

Dietary effect of soybean lecithin on the growth performance, digestive enzyme activity, blood biomarkers, and antioxidative status of striped catfish, Pangasianodon hypophthalmus

“…Hence the lipid deposition and available energy required for the growth increase [ 45 ]. The increased growth rate can be related to improved feed intake and utilization of SBL addition [ 46 ]. Indeed, the study showed a reduced FCR in striped catfish with SBL feeding.…”