Effects of different dietary lipids on growth, body composition and lipid metabolism‐related enzymes and genes in juvenile largemouth bass, Micropterus salmoides

Abstract

This study investigates the effects of different lipids on growth, body composition and lipid metabolism of largemouth sea bass fish Micropterus salmoides. A total of 360 juvenile M. salmoides (mean ± SD mass = 33.83 ± 0.15 g) were randomly stocked into 12 tanks of 0.5 m 3 volume for 8 weeks. Four replicates were made in each group, which were fed one of three diets containing fish oil (FO), soybean oil (SO) or lard oil (LO). The weight gain rate and specific growth rate did not differ among the groups (p > 0.05). Fish oil fish had the lowest condition factor (p < 0.05) and highest serum glucose content (p < 0.05). Crude lipid contents in the whole body and in the liver and muscle of FO fish were significantly lower than in the SO and LO groups (p < 0.05).The fatty acid composition of whole-body lipids was closely correlated with that of the diet. The carnitine palmitoyltransferase 1 (cpt1) activity in the FO group was significantly higher than those in the SO and LO groups (p < 0.05). No significant differences in fatty acid synthase (fasn) activity were observed among the groups (p > 0.05). The Cpt1 and fasn gene expression levels in the FO group were significantly higher than those of the SO and LO groups (p < 0.05). The apolipoprotein B100 gene expression level was significantly higher in the SO group than in the FO group (p < 0.05). Fatty acid-binding protein 1 gene expression levels in the FO and SO groups were not different (p > 0.05) but were both higher than that of the LO group (p < 0.05). The delta-6 fatty acyl desaturase gene expression level in the LO group was significantly higher than that in the FO group (p < 0.05), but lower than that in the SO group (p < 0.05). It can be concluded that FO can be completely replaced by SO or LO in the M. salmoides diet, at least within the 8-week culture period. Different types of dietary lipids significantly affect body condition and hepatic lipid metabolism in M. salmoides. K E Y W O R D S enzyme activity, gene expression, growth performance, lipid metabolism, lipid sources, Micropterus salmoides | 1319 ZHANG et Al.

Responses of largemouth bass ( Micropterus salmoides , Lacépède, 1802) to fishmeal‐, and fish oil‐free diets

“…In other trials, dietary n‐3 to n‐6 ratios of 0.1 have been reported as sufficient for growth, and although the precise fatty acid requirements of LMB remain unknown, it is generally suggested that any dietary needs for EPA/DHA are low and that demands can be satisfied through hepatic conversion of linolenic acid (Yadav et al, 2020). The lack of effect of the three alternative oils, and their blends, on growth, survival and feed conversion, which support the findings of others (Subhadra et al, 2006a; Tidwell et al, 2007; Yun et al, 2013; Zhang, Li, et al, 2019, Zhang, Tan, et al, 2019), illustrates the feasibility of totally excluding FO from LMB diets. It should nevertheless be noted that dietary alternative proteins and oils have been associated with significant changes in various physiological control processes.…”

“…In other trials, dietary n-3 to n-6 ratios of 0.1 have been reported as sufficient for growth, and although the precise fatty acid requirements of LMB remain unknown, it is generally suggested that any dietary needs for EPA/DHA are low and that demands can be satisfied through hepatic conversion of linolenic acid (Yadav et al, 2020). The lack of effect of the three alternative oils, and their blends, on growth, survival and feed conversion, which support the findings of others (Subhadra et al, 2006a;Tidwell et al, 2007;Yun et al, 2013;Zhang, Li, et al, 2019, Zhang, Tan, et al, 2019 oils have been associated with significant changes in various physiological control processes. For example, increased oxygen consumption, elevated pepsin levels, disturbance in various hepatic enzymes, changes in hepatic gene expression profiles, negative impacts on LMB immunity and, inter alia, histopathological effects upon the gut and changes therein to the microbiome have all been detected (e.g., Habte-Tsion et al, 2020;He et al, 2020;Shi et al, 2019;Subhadra et al, 2006a;Zhang, Li, et al, 2019, Zhang, Tan, et al, 2019Zhou et al, 2018;Zhu et al, 2019).…”

“…It should nevertheless be noted that dietary alternative proteins and oils have been associated with significant changes in various physiological control processes. For example, increased oxygen consumption, elevated pepsin levels, disturbance in various hepatic enzymes, changes in hepatic gene expression profiles, negative impacts on LMB immunity and, inter alia , histopathological effects upon the gut and changes therein to the microbiome have all been detected (e.g., Habte‐Tsion et al, 2020; He et al, 2020; Shi et al, 2019; Subhadra et al, 2006a; Zhang, Li, et al, 2019, Zhang, Tan, et al, 2019; Zhou et al, 2018; Zhu et al, 2019). Whether these and other adjustments are consequential to animal welfare and production remains unresolved, but each certainly deserves further examination.…”

Effects of dietary supplementation with peony pollen on growth, intestinal function, fillet quality and fatty acids profiles of common carp

“…In fish, the muscle is one of main sites of lipid deposition (Nanton et al, 2007). The amounts of muscle lipid and unsaturated fatty acid (UFA) contents in fish reflect the flesh nutritive values and healthcare actions (Zhang et al, 2019). Muscle quality is one of the most important factors affecting consumers’ purchase of fish food (Gatlin et al, 2007).…”

Effects of dietary lipid sources on the survival, growth, body composition, antioxidant capacity and expression of antioxidant and pro‐inflammatory genes in juvenile Chinese mitten crab ( Eriocheir sinensis ) reared under three salinities

“…Trachinotus ovatus , Megalobrama amblycephala (Zhang et al, 2018) and Micropterus salmoides (Zhang et al, 2019).…”