Effects of organic selenium supplementation on growth, glutathione peroxidase activity and histopathology in juvenile barramundi (Lates calcarifer Bloch 1970) fed high lupin meal-based diets

Abstract

Very limited information is available on the relationship between dietary selenium (Se) and plant protein (PP) sources in carnivorous marine aquaculture species. Therefore, this study employed a 2  3 experimental layout to investigate the effects of lupin meal (LM) protein inclusion levels (0, 25 and 75%) and organic selenium (OS) levels (0 or 2 g kg-1) on the growth, physiology and histopathology of juvenile barramundi (Lates calcarifer). The experimental diets (LM 0 , LM 0+OS , LM 25 , LM 25+OS , LM 75 and LM 75+OS) were formulated on an isonitrogenous (48.8% crude protein) and isocalorific (20.6 MJ kg-1 gross energy) basis. In the 60-day feeding experiment, final weight (FW), specific growth rate (SGR) and weight gain (WG) were improved by the supplementation of Se in LM-based diets. Fish fed diets containing Se had higher FW, SGR and WG compared with those fed diets lacking Se supplementation (P  0.05). Both LM inclusion levels and Se supplementation levels affected the apparent digestibility coefficient of protein (ADC-P). Meanwhile, survival and the thermal growth coefficient (TGC) were not significantly different among all dietary treatments. The inclusion of a high LM level resulted in decreased glutathione peroxidase (GPx) activities, but this effect was not observed when Se was supplemented in the diets. Furthermore, there was a linear relationship between muscle Se level and Se concentration of the experimental diets. Se-induced myopathy was observed in skeletal muscles of fish fed LM diets without Se supplementation. In addition, structural alteration was found in the liver; however, the kidney, spleen and intestine were histologically normal. Overall, these results suggest that high LM diets supplemented with organic selenium can enhance growth, physiological and histological performances of juvenile barramundi.

Growth, enzymatic glutathione peroxidase activity and biochemical status of juvenile barramundi (Lates calcarifer) fed dietary fermented lupin meal supplemented with organic selenium

“…Fermentation of LM (FLM and FLM OS ) significantly improved growth performance and FCR over the 75‐day period. SGR observed in barramundi in this study is comparable to data from our previous study (Ilham, Fotedar & Munilkumar, ). The works of Van Vo et al () on similar species and Molina‐Poveda, Lucas, and Jover (2013) on juvenile whiteleg shrimp Litopenaeus vannamei led to similar results.…”

“…This study indicates that, although barramundi seem to tolerate a high inclusion level of LM in their diets, based on ADC observed in our previous study (Ilham, Fotedar & Munilkumar, ), high amounts of non‐fermented LM in the diet deleteriously affects FCR, more so than fermented LM and FM. Poor FCR have been recorded in Nile tilapia O .…”

“…Our previous study suggested that 75% of FM protein can be replaced by LM with OS supplementation in the diets of juvenile barramundi (Ilham, Fotedar & Munilkumar, ). Thus, this study was designed to investigate the effects of fermentation of LM simultaneously supplemented with OS on growth, feeding, enzymatic activity, and the biochemical status of the fish.…”

“…The total Se in diet and muscle tissue samples was analysed at the Intertek Genalysis Laboratory (Perth, WA, Australia) using inductively coupled plasma‐mass spectrometry instrument (ICP‐MS, 7500 series, Agilent Technologies, Australia), as previously described in detail (Ilham, Fotedar & Munilkumar, ). Se concentration was measured as dry weight.…”

“…However, based on the above highlight, an integrated approach that combines trace mineral supplementation and fermentation seems to be the best available strategy to enhance the content and bioavailability of trace elements in PP‐based diets for sustainable aquaculture settings. Our recent study suggests that LM‐derived phytate might have constrained Se bioavailability and thus promotes adverse performance in juvenile barramundi (Ilham, Fotedar & Munilkumar, ). It is thus expected that juvenile barramundi fed with LM should perform as well as fish fed with FM diets, as the sole protein source provided trace mineral bioavailability of the diets are simultaneously enhanced.…”