Substituting fishmeal with extruded soybean meal in diets did not affect the growth performance, hepatic enzyme activities, but hypoxia tolerance of Dolly Varden (Salvelinus malma) juveniles

Abstract

Extruded soybean meal (ESBM) showed increased digestibility of crude protein, amino acids and fat, better oil retention capacities, attenuated anti‐nutrient factor effects and improved its nutritive value compared with raw soybean meal, indicating a promising application prospects for ESBM in fish culture. This study aimed to evaluate the effects of substituting fishmeal with ESBM on growth performance, hepatic antioxidant capacity and the resistance to hypoxia stress on juvenile Dolly Varden (Salvelinus malma). Five hundred and forty fish were randomly assigned to six groups fed with iso‐nitrogenous and iso‐energetic diets with ESBM for replacement of 0% (control), 10% (G1), 20% (G2), 30% (G3), 40% (G4) and 50% (G5) fishmeal. After an 81‐day feeding trial, groups fed ESBM substituted diets (G2 to G5) showed no significant differences in survival rates, final body weights, weight gain rates, feed conversion ratios, specific growth rates, hepatosomatic indexes and condition factors with the control group (G0), reflecting normal food intake and growth performance. The hepatic enzyme activities of total antioxidant capacity, catalase and superoxide dismutase were not affected by ESBM substituted diets, showing no harmful effects on ROS eliminating abilities. Hepatic HSP70 expression levels had increased 1.3 times for G5 group, reflecting a less tolerance to hypoxia for fish fed diets with high substituting level of ESBM. In conclusion, replacing, despite 50%, fishmeal with ESBM in diets had no detrimental effects on growth performance and hepatic enzyme activities, but lowering the hypoxia tolerance of juvenile Dolly Varden (Salvelinus malma).

Effects of Substituting Fish Meal with Two Types of Soybean Meal on Growth, Enzyme Activities, and Intestinal Morphology in Juvenile Rhynchocypris lagowskii

“…This explains why R. lagowskii had a higher acceptance of ESBM compared with SBM in our study. And the same results were found in Asian Swamp Eel Monopterus albus (Zhang et al 2015), Dolly Varden (Meng et al 2020), and Rainbow Trout (Santizo‐Taan et al 2020). It is worth noting that the extrusion process of ESBM cannot effectively remove heat‐stable antinutritional factors (mainly including soya‐saponins, soy antigen protein, phytic acid, isoflavone, oligosaccharide, tannin) or optimize the composition of amino acids profile (Zhang et al 2015).…”

“…Extrusion technology could effectively reduce the antinutritional factor content in SBM and increase the free amino acid content (Pongmaneerat and Watanabe 1993; Berenti et al 2021). Studies on broiler chicks and Dolly Varden have revealed that ESBM increased the digestibility of crude protein, amino acids, and fat and weakened the effect of antinutritional factors compared with SBM (Jahanian and Rasouli 2016; Meng et al 2020). These studies show that ESBM has a good application prospect in the feed industry and also partly explain why ESBM has less effect on muscle crude protein content of R. lagowskii compared with SBM.…”

“…In terrestrial livestock (broiler chicks Gallus gallus domesticus , Holstein dairy calves, and weanling pigs Sus sp.) and also fish (Dolly Varden Salvelinus malma , Rainbow Trout Oncorhynchus mykiss , Gilthead Seabream Sparus aurata , Japanese Flounder Paralichthys olivaceus ), extruded soybean meal (ESBM) has been shown to improve the weight gain ratio, specific growth rate, and digestibility of dry matter and crude protein compared with SBM (Li et al 1991; Saitoh et al 2003; Venou et al 2006; Barrows et al 2007; Lu et al 2010; Jahanian and Rasouli 2016; Meng et al 2020; Santizo‐Taan et al 2020; Berenti et al 2021). These studies indicated that ESBM had a good application prospect in aquatic formula feed.…”

Taurine supplementation increases the potential of fishmeal replacement by soybean meal in diets for largemouth bass Micropterus salmoides

“…The capacity of utilizing soybean meal as a dietary fishmeal substitute has been evaluated in a wide range of carnivorous fish species, such as giant snakehead Channa micropeltes (Hien et al, 2015), Japanese seabass Lateolabrax japonicas (Zhang et al, 2016, 2018), European sea bass Dicentrarchus labrax (Bonvini et al, 2017), Dolly Varden Salvelinus malma (Meng et al, 2019), Asian seabass Lates calcarifer (Ma et al, 2019) and rainbow trout Oncorhynchus mykiss (Yeşilayer & Kaymak, 2020). Early study suggested that average final weight of largemouth bass declined significantly when reducing dirtary fishmeal level from 300 g/kg to 150 g/kg, with soybean meal used as a fishmeal substitute (Tidwell et al, 2005).…”

“…Among the plant ingredients used in aqua‐feed, soybean has been demonstrated as an excellent protein source due to its high protein digestibility, relative balance of amino acids, huge global production and reasonable market price (Metts et al, 2011; Wang et al, 2006). The potential of replacing fishmeal with soybean‐derived ingredients (soybean meal, soy protein concentrate and isolated soy protein) in diets for carnivorous fish species has been intensively evaluated (Biswas et al, 2019; Bonvini et al, 2017; Hossain et al, 2019; Ma et al, 2019; Meng et al, 2019; Novriadi et al, 2017; Yaghoubi et al, 2016; Yeşilayer & Kaymak, 2020; Zhang et al, 2016, 2018). And results from these studies suggested that fishmeal replacement level by soybean‐derived ingredients varies among different fish species.…”