Effects of Lysophosphatidylcholine on Intestinal Health of Turbot Fed High-Lipid Diets

Abstract

An 8-week feeding trial was conducted, where turbot were fed four experimental diets, containing different LPC levels (0%, 0.1%, 0.25%, and 0.5%, named LPC0, LPC0.1, LPC0.25, and LPC0.5, respectively). The intestinal morphology results showed that there were no widened lamina propria and mixed inflammatory cells in the LPC-supplemented groups. Dietary LPC remarkably decreased the expression of TLRs (TLR3, TLR8, TLR9, and TLR22), MyD88, and signaling molecules (NF-κB, JNK, and AP-1). Similarly, diets with LPC supplementation markedly depressed the gene expression of NF-κB and JNK signaling pathway downstream genes (TNF-α, IL-1β, Bax, Caspase9, and Caspase-3). Furthermore, dietary LPC modified the intestinal microbial profiles, increasing the relative abundance of short-chain fatty acids-producers, lactic acid bacteria, and digestive enzyme-producing bacteria. Predictive functions of intestinal microbiota showed that turbot fed LPC diets had a relatively higher abundance of functions, such as lipid metabolism and immune system, but a lower abundance of functions, such as metabolic diseases and immune system diseases. The activities of intestinal acid phosphatase and alkaline phosphatase were also increased by dietary LPC. In conclusion, LPC supplementation could regulate the intestinal mucosal barrier via the TLR signaling pathway and alter the intestinal microbiota profile of turbot fed high-lipid diets.

Physiological Benefits of Dietary Lysophospholipid Supplementation in a Marine Fish Model: Deep Analyses of Modes of Action

“…In terms of enterocyte metabolism, we detected 18 upregulated proteins, which clustered with a high PPI-enrichment p -value. As expected, lipid metabolism was improved by dietary LPLs, as suggested previously [ 6 , 7 , 27 ]. LPLs increase glucose uptake in rainbow trout ( Oncorhynchus mykiss ; [ 40 ]) as well as in broiler chickens [ 41 ].…”

“…Improvements in fish growth and/or feed utilization caused by dietary lysolecithin supplementation have been reported previously in common carp, crucian carp, catfish, and turbot [ 6 , 7 , 26 , 27 ], as well as terrestrial species. The results of the present study agree, showing a significant increase in body weight of 5% in salmon after 12 weeks of being fed an LPL-supplemented diet.…”

“…We analyzed the levels of circulating lipid, including lipid fractions such as TAG, PL, and TC, under pre-feeding conditions (samples were obtained after overnight fasting). There are no data on the effects of dietary LPLs on circulating PL levels in the literature, but Liu et al [ 27 ] did detect lower levels of circulating TAG and TC in LPL-fed channel catfish. Furthermore, we previously demonstrated in gilthead sea bream that diets with higher lipid levels corresponded to lower sums of lipids in the plasma after overnight fasting [ 30 ].…”

“…One of the expected effects of dietary LPLs in the liver is the prevention of the accumulation of abnormal fats [ 44 ]. For instance, the inclusion of lysolecithin in the diet of channel catfish led to a lower lipid content in the liver and increases in intestinal lipase activity [ 27 ], which were also observed in rainbow trout [ 13 ]. This might be because LPLs facilitate the transport of the lipids produced from lipoprotein synthesis from the liver to the adipose tissue.…”

“…Supplemental bile acids, which have similar emulsifying properties to those of LPLs, have been shown to increase the activities of antioxidant enzymes and alleviate the damage to the antioxidant system caused by high fat levels in livestock [ 5 ]. In fish, Liu et al [ 27 ] reported that the response to stimulus is involved in the upregulated response to handling and confinement stress in trout, while Raposo de Magalhaes et al [ 53 ] also referred to this GO term in the analysis of the stress-responsive hepatic proteome in gilthead sea bream. In parallel, a recent study [ 54 ] in largemouth bass ( Micropterus salmoides ) demonstrated that the addition of LPLs increased the abundance of beneficial microbiota and decreased the abundance of harmful microbiota in the intestinal flora, which could also be related to the proposed less-reactive condition of fish receiving LPL supplementation.…”