Effects of Different Viscous Guar Gums on Growth, Apparent Nutrient Digestibility, Intestinal Development and Morphology in Juvenile Largemouth Bass, Micropterus salmoides

Abstract

An 8-week feeding trial was conducted to investigate the effects of different viscous guar gums on the growth performance, apparent nutrient digestibility, intestinal development and morphology of juvenile largemouth bass. Four isoproteic and isolipidic diets (crude protein 42.5%, crude lipid 13.7%) were formulated to contain 8% cellulose (Control group), 8% low viscous guar gum with 2,500 mPa s (Lvs-GG group), 8% medium viscous guar gum with 5,200 mPa s (Mvs-GG group) and 8% high viscous guar gum with 6,000 mPa s (Hvs-GG group), respectively. Each diet was fed to quadruplicate groups of 40 fish (6.00 ± 0.01 g) per repetition. Dietary guar gum inclusion significantly decreased the weight gain rate, specific growth rate, protein efficiency ratio, protein productive value and lipid deposition rate, and these parameters decreased considerably with increasing guar gum viscous and were lowest in the Hvs-GG group. Dietary guar gum inclusion significantly decreased the apparent digestibility of dry matter, crude protein and crude lipid, and these parameters decreased considerably with increasing guar gum viscous and were lowest in the Hvs-GG group. Intestinal protease, lipase and creatine kinase activities in the guar gum groups were significantly lower than those in the control group, and intestinal protease and lipase activities decreased considerably with increased guar gum viscous. Intestinal alkaline phosphatase activity in the Hvs-GG group and intestinal Na+/K+-ATPase activity in the Mvs-GG and Hvs-GG groups were significantly lower than those in the Lvs-GG and control groups. Serum high-density lipoprotein, total cholesterol and triglyceride concentrations and superoxide dismutase activity in the guar gum groups were significantly lower than those in the control group. Intestinal villus height and muscular thickness in the guar gum groups were considerably higher than those in the control group, whereas the goblet cell relative number in the Mvs-GG and Hvs-GG groups and the microvillus height in the Lvs-GG and Hvs-GG groups were significantly lower than those in the control group. The expression level of IGF-1 in the guar gum groups and the expression level of GLP-2 in the Mvs-GG and Hvs-GG groups were significantly higher than those in the control group. These results indicated that guar gum diets adversely affected intestinal morphology, decreased intestinal digestive and absorptive enzyme activities, and caused poor nutrient digestibility and growth performance in juvenile largemouth bass. Moreover, the adverse effects of guar gum are closely related to its viscous, and high viscous guar gum produces more extreme negative impacts on juvenile largemouth bass.

Different Types of Non-Starch Polysaccharides Alter the Growth, Intestinal Flora and Serum Metabolite Profile of Grass Carp, Ctenopharyngodon idella

“…BUN is the end product of amino acid catabolism in fish, while AST is an amino acid metabolizing enzyme distributed in the liver and released into the blood when liver cells are damaged [ 1 ]. Therefore, an increase in these parameters suggests that dietary SNSP promotes proteolytic metabolism and induces liver damage [ 41 , 42 , 43 ]. Similarly, our previous studies also showed that dietary SNSP induces liver damage in rainbow trout and largemouth bass ( Micropterus salmoides ) [ 1 , 41 ].…”

“…Therefore, an increase in these parameters suggests that dietary SNSP promotes proteolytic metabolism and induces liver damage [ 41 , 42 , 43 ]. Similarly, our previous studies also showed that dietary SNSP induces liver damage in rainbow trout and largemouth bass ( Micropterus salmoides ) [ 1 , 41 ]. This evidence suggests that dietary SNSP is the main type of NSPs causing liver damage in fish.…”

Feeding juvenile largemouth bass (Micropterus salmoides) with carboxymethyl cellulose with different viscous: Impacts on nutrient digestibility, growth, and hepatic and gut morphology

“…Four practical diets containing 8% microcrystalline cellulose (MC) and carboxymethyl cellulose (CMC) of 2,500, 5,000, and 6,500 mPa s [hereinafter MC, low-viscosity CMC (Lvs-CMC), medium-viscosity CMC (Mvs-CMC), and high-viscosity CMC (Hvs-CMC) groups, respectively] were designed (values in millipascal second denote the dynamic viscosity, which represents the internal friction force generated by the interaction of fluids between two 1-m 2 flat plates with a distance of 1 m when they move relative to each other at a speed of 1 m/s). The control group data have been published in a previous study (Liu et al, 2022b). All materials were first finely milled into powder, mixed thoroughly after being screened using a 0.30-mm diameter mesh, and then accurately weighed.…”

“…The visceral mass, gut, and liver were weighed accurately and the intestinal length measured. Another group of fish (n = 4 from each cage) was randomly selected for the collection of blood samples according to the method described by Liu et al (2022b). The proximal and distal intestines of two fish from each cage were collected into separate Eppendorf (EP) tubes and stored at −80°C for subsequent analysis.…”

“…However, dietary NSPs cannot be directly digested by fish. They are trapped in the intestine, they inhibit nutrient digestion and absorption, and they reduce fish growth (Cai et al, 2019;Ren et al, 2020;Deng et al, 2021;Liu et al, 2022a;Liu et al, 2022b).…”