Impact of exogenous lipase supplementation on growth, intestinal function, mucosal immune and physical barrier, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella)

Exogenous enzymes as functional additives in finfish aquaculture

“…Lipase could give glycerides with a more than twofold increase in n‐3 PUFA (polyunsaturated fatty acid) content over the original fish oils. Liu et al () stated that optimal dietary exogenous lipase significantly increased the immune performance by regulating the activities of immune‐related enzymes, and also the relative mRNA levels of antimicrobial peptides, anti‐inflammatory cytokines, signalling molecule inhibitor protein‐κBɑ and target of rapamycin. Zheng et al () informed that exogenous lipase could help hydrolysing the crude lipids in feedstuffs to produce polyunsaturated fatty acid, which could improve the quality of fish meal, and the environment of the beneficial microorganism in the gastrointestinal tract of fish, and might promote the proliferation of beneficial microorganism, which contributes to intestinal health status in fish.…”

“…These results indicated that optimal exogenous lipase supplementation might be partly through hydrolysis of lipids to affect the intestinal tight junction complex, antioxidant capacity and related signalling molecules to improve intestinal health of fish. Nevertheless, compared with optimal exogenous lipase supplementation, high levels of exogenous lipase supplementation decreased growth performance, intestinal immunity, junction complexes and antioxidant capacity in young grass carp, and these negative effects may be due to the high levels of free fatty acids (FFAs), which are the primary lipolysis products by lipase (Liu et al, ).…”

“…It has been identified that appropriate addition of exogenous enzymes in the feed can supplement the deficiency of endogenous enzymes and improve the growth performance (Drew et al, ). In addition, previous studies have evidenced that dietary cellulase can increase the ether extract content of the body tissue by 100g/kg, and the addition of phytase (500 U/kg) and cellulase (2 g/kg) in the feed can increase the lipid content of the body tissue (Baruah et al, ; Xavier et al, ). To promote immune performance and pathogen resistance (Abo et al, ; Baruah et al, ; Liu et al, , ; Song et al, ; Zheng et al, ). The immune system of fish is affected by a variety of factors, including disease, pollutants, hormones and feed (Doan et al, ).…”

“…Previous reports have shown that the addition of up to 1,000 units/kg of phytase feed could significantly improve the immune response and survival rate of Nile tilapia after being challenged by A. hydrophila (Abo et al, ). In addition, in low‐protein and high‐lipid diets, dietary exogenous lipase improved fish intestinal immune response, which was partly by increasing the acid phosphatase activity and complement component 3 contents, downregulating proinflammatory cytokines gene expression, upregulating antibacterial peptides and anti‐inflammatory cytokine gene expression, which may be partially attributed to regulate nuclear factor‐kB p65 protein inhibitors, κBɑ, IκB intestinal kinase and rapamycin target signalling pathway in fish (Liu et al, ). It is generally accepted that the changes in diet composition have an impact on fish microbiota (Einar et al, ; Li et al, ; Ringo et al, ; Silva et al, ). Recently, more and more studies have been carried out to investigate the effects of exogenous enzymes on the microbiota of fish, and elucidating that the effects of dietary enzymes on intestinal status are both timely and novel.…”

“…3. To promote immune performance and pathogen resistance (Abo et al, 2018;Baruah et al, 2010;Liu et al, 2013Liu et al, , 2016Song et al, 2017;Zheng et al, 2019). The immune system of fish is affected by a variety of factors, including disease, pollutants, hormones and feed (Doan et al, 2019).…”