Imbalanced lysine to arginine ratios reduced performance in juvenile cobia (Rachycentron canadum) fed high plant protein diets

Abstract

Cobia (8.4 ± 0.1 g body weight) were fed to satiation with three test diets of high plant protein‐based ingredients and different lysine to arginine ratios, and one commercial diet (currently used for cobia rearing in Vietnam as a control for growth) for 6 weeks. The test diets contained 206 g marine ingredients kg−1, including fishmeal, krill meal and fish protein concentrate (in order of high to low inclusion), while the rest of the dietary protein was a blend of soya and pea protein concentrate, wheat protein and sunflower meal. Crystalline lysine and arginine were added in the test diets to produce either a balanced lysine to arginine ratio (BL/A; 1.1) and a high or low lysine to arginine ratio (HL/A; 1.8 and LL/A; 0.8, respectively). There were no significant differences in final body weight, weight gain, feed conversion ratio or protein gain between cobia fed BL/A‐ and commercial control diet (CCT). Cobia fed BL/A diet performed better than fish fed either HL/A‐ or LL/A diet. This was partly due to a higher feed intake and protein and lipid gain in cobia fed BL/A diet as compared to HL/A‐ and LL/A diet.

The role of dietary methionine concentrations on growth, metabolism and N-retention in cobia (Rachycentron canadum) at elevated water temperatures

“…(Olhão, Portugal). The experimental diets (Table ) were formulated based on previous results in cobia (Nguyen et al, ; Zhou et al, ). In the present study, crystalline DL‐methionine was added with different amount to make a diet deficient in methionine M9 (9.1 g/kg), a diet with sufficient methionine M12 (12.8 g/kg) and a diet with surplus methionine M16 (16.8 g/kg; Table ).…”

“…The experimental tanks were fibreglass rectangular tanks (80 × 50 × 60 cm), with 200 L water filled, in two water recirculation subunits with continuous aeration (as described in Nguyen et al, ). Salinity was 29 ± 3.1 ppt, pH 7.8–8.3, oxygen 4.6 ± 0.5 mg/L and NH 3 < 0.03 mg/L.…”

“…Growth is mainly accretion of body protein, and proper feeding protocols, together with a balanced feed composition as well as optimized amino acid (AA) metabolism, are key components to optimize growth and reduce N‐waste. We have previously demonstrated that a dietary lysine‐to‐arginine ratio close to 1 (one) would result in the best performance of juvenile cobia and that cobia tolerate high inclusion of plant protein, given that the dietary AA profiles are balanced (Nguyen, Rønnestad, Buttle, Lai, & Espe, ). We have also started to explore the endocrine control of appetite in cobia and demonstrated that as seen for many vertebrates, neuropeptide Y acts as an orexigenic signal in the regulation of feed intake (Nguyen et al, ).…”

Effects of dietary L‐lysine supplementation on growth, body composition and muscle‐growth‐related gene expression with an estimation of lysine requirement of GIFT tilapia

“…Moreover, it plays an important role in the synthesis of carnitine, which is important for the transport of long‐chain fatty acids into the mitochondrion for energy generation. In addition, dietary supplementation of lysine improves feed utilization (Li et al, ), nitrogen retention (Cao et al, ) and also reduce body lipid content of fish (Burtle & Liu, ; Nguyen, Rønnestad, Buttle, Lai, & Espe, ).…”

The effects of dietary protein levels with amino acid supplementation on the growth performance, haematological profile and histology of meagre (Argyrosomus regius) in two different size classes

“…Lysine and methionine, which are used to synthesize nitrogen containing compounds, are the two most restrictive amino acids in the diets for finfish (Li et al., ) when fishmeal is replaced by high plant protein sources. Consequently, accurate assessment or knowing of these two amino acid requirements is needed to environmentally and cost‐effective of aquafeeds (Güroy et al., ; Mai, Zhang et al., ; van Nguyen, Rønnestad, Buttle, van Lai & Espe, ; NRC, ; Zhou et al., ). Recent research revealed that inclusion of lysine and methionine when high plant proteins containing and lowering protein level in diets could be enhanced the growth performance and digestive capacity of finfish (Davies & Morris, ; Gan et al., ; Gaylord & Barrows, ; Jiang et al., ; Kroeckel, Dietz, Schulz & Susenbeth, ; Rolland, Dalsgaard, Holm, Gómez‐Requeni & Skov, ).…”