Metabolic responses of juvenile GIFT strain of Nile tilapia ( Oreochromis niloticus ) to dietary L‐tryptophan supplementation

Abstract

A 60‐day indoor feeding trial was conducted to evaluate the effects of dietary tryptophan supplementation on growth performances, whole‐body chemical composition, expression of muscle growth‐related genes (MyoD, myogenin and myostatin), and haematological and biochemical responses of juvenile genetically improved farmed tilapia (GIFT). Five corn–soy‐based isonitrogenous and isoenergetic diets were formulated to contain graded levels of dietary tryptophan (2.6, 3.2, 3.7, 4.2 and 4.8 g/kg of diet). Each diet was randomly assigned to triplicate groups of 30 fish (5.3 ± 0.1 g) per experimental unit, which were fed thrice a day (9:00, 13:00 and 17:00 hr). Maximum growth performances and feed utilization were observed in fish fed tryptophan at 3.7 g/kg of diet. There was no significant (p > .05) effect on whole‐body composition and amino acid profile by dietary tryptophan supplementation. However, significant (p < .05) differences were observed in plasma metabolites and the mRNA expression of MyoD, myogenin and myostatin. Serum cortisol level was found significantly lowest in fish fed tryptophan at 3.7 g/kg of diet. Second‐order polynomial regression analysis of weight gain and nitrogen gain against dietary tryptophan levels indicated that the optimum dietary tryptophan requirement for maximum growth and feed utilization of juvenile GIFT tilapia was 3.8 g/kg of diet.

Optimizing amino acid balance in fish meal‐free diets for GIFT strain of Nile tilapia ( Oreochromis niloticus ) by deletion method

“…When fish is subjected to stress, in order to resist from stress, more glucose is produced as demonstrated in rainbow trout (Lepage et al, 2002) and common carp (Hoseini & Hosseini, 2010). The dietary supplementation of tryptophan has been reported to reduce stress, and therefore, reduced glucose level in Nile tilapia (Zaminhan et al, 2018) and GIFT tilapia (Prabu, Felix, Uma, Ahilan, et al, 2020) was observed compared with tryptophan‐unsupplemented diets, which justify reduced glucose content in the present study of the fish fed tryptophan‐supplemented diets.…”

“…The –AA diet was formulated using plant‐based ingredients without supplementation of crystalline amino acids. The balanced diet (BD) was formulated based on the findings of our previous studies (Prabu et al, 2019; Prabu, Felix, Uma, Ahilan, et al, 2020; Prabu, Felix, Uma, & Praveenraj, 2020) with supplementation of DL‐methionine, L‐lysine, L‐tryptophan and L‐arginine. The other diets were formulated by the deletion technique, in which the BD was diluted with cassava starch resulting in a reduction in each amino acid, such as methionine (‐Met), lysine (‐Lys), tryptophan (‐Trp) and arginine (‐Arg) (Table 1).…”

“…Therefore, it is essential to frequently validate and update the nutritional requirement levels of tilapia in order to meet their new genetic demands. In this context, the authors carried out studies and found that the optimum level of methionine, lysine, tryptophan and arginine were 9.0 g/kg (Prabu et al, 2019), 18.3 g/kg (Prabu et al, 2020), 3.8 g/kg (Prabu et al, 2020) and 16.7 g/kg of diet, respectively, for attaining better growth performance in GIFT tilapia.…”

Effects of dietary protein substitution of fish meal with bioprocessed poultry by‐product meal on growth performances, nutrient utilization, whole‐body composition and haemato‐biochemical responses of GIFT tilapia reared in floating cages

“…Haematological and biochemical parameters are widely used as an indicator of health and physiological status of fish (Zhou et al, 2005). Haematological parameters such as Hb, Ery, Leuk, Ht, MCV, MCH and MCHC are representing the immunity response of host fish (Prabu et al, 2020). Blood lipid and glucose levels were associated with lipid metabolism of body and glucose metabolism as well as nutrient utilization and liver health of animals, respectively (Zhao, 2006).…”

Growth performances and nutrient utilization efficiency of GIFT tilapia reared in floating net cages fed with bioprocessed silkworm pupae meal

“…Haemato-biochemical parameters are an important indicator which reflects health and physiological status of fish (Zhou et al, 2005). Haematological parameters such as Hb, WBC, RBC, haematocrit, MCV, MCH and MCHC are representing the immunity response of host fish (Prabu et al, 2020). The present study revealed that complete replacement of fish meal protein with SWP and BSWP had no influence on the haematological parameters in GIFT tilapia.…”