Soyabean glycinin depresses intestinal growth and function in juvenile Jian carp (Cyprinus carpiovar Jian): protective effects of glutamine

Abstract

This study investigated the effects of glycinin on the growth, intestinal oxidative status, tight junction components, cytokines and apoptosis signalling factors of fish. The results showed that an 80 g/kg diet of glycinin exposure for 42 d caused poor growth performance and depressed intestinal growth and function of juvenile Jian carp (Cyprinus carpio var. Jian). Meanwhile, dietary glycinin exposure induced increases in lipid peroxidation and protein oxidation; it caused reductions in superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities; and it increased MnSOD, CuZnSOD, GPx1b and GPx4a mRNA levels, suggesting an adaptive mechanism against stress in the intestines of fish. However, dietary glycinin exposure decreased both the activity and mRNA levels of nine isoforms of glutathione-S-transferase (GST) (α, μ, π, ρ, θ, κ, mGST1, mGST2 and mGST3), indicating toxicity to this enzyme activity and corresponding isoform gene expressions. In addition, glycinin exposure caused partial disruption of intestinal cell-cell tight junction components, disturbances of cytokines and induced apoptosis signalling in the distal intestines > mid intestines > proximal intestines of fish. Glycinin exposure also disturbed the mRNA levels of intestinalrelated signalling factors Nrf2, Keap1a, Keap1b, eleven isoforms of protein kinase C and target of rapamycin/4E-BP. Interestingly, glutamine was observed to partially block those negative influences. In conclusion, this study indicates that dietary glycinin exposure causes intestinal oxidative damage and disruption of intestinal physical barriers and functions and reduces fish growth, but glutamine can reverse those negative effects in fish. This study provides some information on the mechanism of glycinin-induced negative effects.

Effects of dietary protein levels on the disease resistance, immune function and physical barrier function in the gill of grass carp ( Ctenopharyngodon idella ) after challenged with Flavobacterium columnare

“…First, we observed no changes or decreases in enzyme activities because the increases in mRNA levels of antioxidant enzymes indicated an adaptive mechanism; the fish gill required more de novo synthesis of those antioxidant enzymes to scavenge excess ROS, but at either low or high levels of protein, the activities of those antioxidant enzymes were constantly inactivated by the ROS. Similar results were observed in previous studies in our laboratory with Jian carp (Cyprinus carpio var Jian) [80,81]. Second, the enzyme activities are influenced not only by gene transcription but also by posttranscriptional processes (such as translation and posttranslational modification) in fish [80].…”

“…Similar results were observed in previous studies in our laboratory with Jian carp (Cyprinus carpio var Jian) [80,81]. Second, the enzyme activities are influenced not only by gene transcription but also by posttranscriptional processes (such as translation and posttranslational modification) in fish [80]. However, determination of the exact mechanism requires further investigation.…”

Effects of dietary Radix Rehmanniae Preparata polysaccharides on the digestive enzymes, morphology, microbial communities and mucosal barrier function of the intestine of Luciobarbus capito

“…Polysaccharides are prebiotics that have received increasing attention in fish aquaculture (Daniels & Hoseinifar, 2014;Song et al, 2014). Digestive and absorptive functions are closely associated with intestinal structural integrity and digestive enzymes (Jiang et al, 2015). Digestive and absorptive functions are closely associated with intestinal structural integrity and digestive enzymes (Jiang et al, 2015).…”

Dietary low or excess levels of lipids reduced growth performance, and impaired immune function and structure of head kidney, spleen and skin in young grass carp (Ctenopharyngodon idella) under the infection of Aeromonas hydrophila

“…To our knowledge, not only gene transcription but also the post-transcriptional events (such as posttranslational modification) influence on enzymatic activity [94]. It was reported that the mRNA levels of MnSOD in rat lungs was significantly up-regulated, though no correlated increase in enzyme activity was seen [95].…”