Dietary lysine modulates growth performance, haemato‐biochemical indices, non‐specific immune response, intestinal enzymatic activities and antioxidant properties of rainbow trout, Oncorhynchus mykiss fingerlings

Abstract

The experimental trial was conducted to assess the appropriate utilization of dietary lysine (Lys) required for Oncorhynchus mykiss fingerlings. Six isonitrogenous (450 g/kg CP) and isoenergetic (20.90 kj/g GE) casein-gelatine based diets supplemented with varying concentrations of dietary Lys (14.0, 16.5, 19.0, 21.5, 24.0. and 26.5 g/kg, dry diet) were formulated. For each incremental level, all diets were randomly distributed in triplicate groups of 20 fish (1.79 ± 0.06 g/fish; 5.70 ± 0.42 cm/fish) and were fed in the morning and evening time (08:00 and 17:00 h) at the rate of 5% BW day −1 .After the end of the trial, maximum live weight gain (355.21), protein efficiency ratio (1.69 g/kg), better-feed conversion ratio (1.31) and maximum body protein deposition were recorded at 21.50 g/kg increment of Lys in the diet. Highest body protein, lowest moisture and intermediate fat contents were noted in the fish fed 21.50 g/ kg of dietary Lys containing diet, while body ash values did not show any significant (p ˃ .05) changes at each increment of Lys in the diets, except at lower increments, where highest ash content was observed. Hepatosomatic index (HSI) value was noted lowest in the fish fed with diets containing 21.50 g/kg Lys level, while haematological variables also exhibit considerable changes with the addition of each Lys inclusion level. Maximum haemoglobin (Hb), haematocrit (Hct) and red blood cell (RBC) count were also noted at 21.50 g/kg Lys fed diet. Significant variations (p < .05) in plasma variables, non-specific immune system, intestinal enzymatic activities and antioxidant status were also observed in the fish fed with varying dietary Lys containing diets.However, cholesterol, triglycerides, amylase, lipase and superoxide dismutase (SOD) did not show any differences with respect to Lys inclusion levels. Our findings suggest that 21.60 g/kg dietary Lys, corresponding to 48.0 g/kg of dietary protein should be incorporated in the diet of rainbow trout for better growth and efficient nutrient conversion of this species, and also for the improvement in fish health. Collectively, this study indicated that an appropriate amount of Lys improve fish growth, haematobiochemical parameters, immune response and digestive ability, and also up-regulate the antioxidant status.

Effects of dietary lysine levels on growth performance and antioxidative capacity in channel catfish Ictalurus punctatus

“…Lysine is the most limiting amino acid in many plant proteins (Hauler & Carter, 2001; National Research Council (NRC) 2011). As an essential amino acid, lysine is significant for aquatic animals due to its role in growth, metabolism and immune response (Ahmed & Ahmad, 2021; Walton et al, 1984; Yang et al, 2020). Previous studies reported that appropriate lysine level improved the growth performance and feed utilization of grass carp ( Ctenopharyngodon idellus ; Dh et al, 2021), Nile tilapia ( Oreochromis niloticus ; Romaneli et al, 2021) and blunt snout bream ( Megalobrama amblycephala ; Cai et al, 2018).…”

“…In sub‐adult grass carp, the activities of catalase (CAT) and glutathione peroxidase (GSH‐Px) increased with the increase of dietary lysine levels (Li et al, 2014). In rainbow trout ( Oncorhynchus mykiss ), an appropriate amount of lysine also increased the antioxidative status of fish (Ahmed & Ahmad, 2021). Nuclear factor erythroid 2‐related factor 2 (Nrf2) is a critical transcription factor in cellular oxidative stress response (Hui & Yang, 2018).…”

Effects of dietary lysine level on the growth performance, protein metabolism, and antioxidant status in Hemibagrus wyckioides juveniles

“…However, the intestinal trypsin and lipase activities were decreased by excessive dietary lysine, indicating the digestive function of H. wyckioides was adversely affected by the imbalance of dietary amino acids. Previous studies have also confirmed that an excessive lysine level might inhibit the activities of trypsin and lipase (Ahmed & Ahmad, 2021;Huang et al, 2022). Therefore, appropriate dietary lysine may enhance digestive enzyme activities and thereby improve the digestion and growth of fish (Li et al, 2014).…”

Seasonal Variation in Fatty Acid and Amino Acid Composition of the Patagonian Marine Polychaete Abarenicola pusilla and Its By-Products

“…Since LYS is a limiting EAA found in low quantities in vegetable proteins [27], it could be one of the main advantages of using eviscerated whole polychaetes as an additional ingredient in fsh-free aquafeeds. Furthermore, it has been documented that LYS above the minimum required dietary level is essential for the nonspecifc immune system of the rainbow trout, Oncorhynchus mykiss [28], and favors the gastrointestinal development of agastric fsh [29].…”