Evaluation of Optimum Dietary Threonine Requirement by Plasma Free Threonine and Ammonia Concentrations in Surgically Modified Rainbow Trout, <i>Oncorhynchus mykiss</i>

Abstract

This study was carried out to evaluate the dietary threonine requirement by measuring the plasma free threonine and ammonia concentrations in rainbow trout, Oncorhynchus mykiss after dorsal aorta cannulation. A total of 70 fish (average initial weight 506±8.2 g) were randomly distributed into each of the 14 net cages (5 fish/cage). After 48 hours (h) of feed deprivation, each group was intubated at 1% body weight with one of the seven L-amino acid based diets containing graded levels of threonine (0.42%, 0.72%, 0.92%, 1.12%, 1.32%, 1.52%, or 1.82% of diet, dry matter basis). Blood samples were taken at 0, 5, and 24 h after intubation. Post-prandial plasma free threonine concentrations (PPthr) of fish 5 h after intubation with diets containing 1.32% or more threonine were significantly higher than those of fish intubated with diets containing 1.12% or less threonine (p<0.05). Post-absorptive free threonine concentrations (PAthr) after 24 h of intubation of the fish with diets containing 0.92% or more threonine were significantly higher than those of fish intubated with diets containing 0.72% or less threonine. Post-prandial plasma ammonia concentrations (PPA, 5 h after intubation) were not significantly different among fish intubated with diets containing 1.12% or less threonine, except the PPA of fish intubated with diet containing 0.42% threonine. Broken-line model analyses of PPthr, PAthr, and PPA indicated that the dietary threonine requirement of rainbow trout should be between 0.95% (2.71) and 1.07% (3.06) of diet (% of dietary protein on a dry matter basis).

Partial Substitution of Fish Oil with Microalgae (Schizochytrium sp.) Can Improve Growth Performance, Nonspecific Immunity and Disease Resistance in Rainbow Trout, Oncorhynchus mykiss

“…Growth performance from the current study compares favorably with similar studies [31,32] carried out previously with the same species. Our observations are in agreement with those of earlier reports, suggesting a fish oil replacement level of 80~90% using alternative plant/animal lipid sources without compromising the growth performance in Rainbow trout [24].…”

Amino acid levels from blood plasma of rainbow trout raised in different seasons and farming systems

“…The circulating level of essential and non-essential amino acids in fish is mainly influenced by the quality of the administered feed (YUN & al [24]; YUN & al [25]) and the voluntary intake rate. Fish are poikilothermic organisms and any changes in medial parameters lead to behavioral and physiological changes (SARAVANAN & al [26]; HOLT & JØRGENSEN [27]).…”

Modelado matemático del efecto del hidrolizado de vísceras en el desempeño productivo de trucha arcoíris (Oncorhynchus mykiss)

“…La treonina es el tercer aminoácido limitante después de la metionina y la lisina para algunas especies de peces, y potencialmente marginal o limitante en las formulaciones de alimentos. La deficiencia de treonina provoca un retraso en el crecimiento y una reducción del consumo de alimento en la trucha arco iris (Rodehutscord et al, 1995); según Yun Hyeonho et al, (Yun et al, 2015), las necesidades dietéticas de treonina basado en las concentraciones plasmáticas de amoníaco posprandial (PPA), en O. mykiss debe estar entre 0,95% (2,71) y 1,07% (3,06) de la dieta (% de proteína dietética en base a materia seca), dentro del rango de la dieta para las especies de peces de cultivo (0,6% a 2,0%), aunque se reconoce que la PPA es afectada por los niveles dietéticos de arginina, lisina, metionina y valina (Yun et al, 2015).…”

“…Según Witono et al, (2016) los requerimientos dietéticos de lisina de las especies de peces carnívoros de agua dulce, son más altos que los de las especies omnívoros y herbívoros; así para la trucha arco iris este valor oscila entre 2,34% y 6,1% de la dieta (proteína dietética) ( (Rodehutscord et al, 1995y Yun et al, 2015. Consecuentemente, el principal determinante del crecimiento de los peces, es el resultado del reclutamiento de nuevas fibras musculares (hiperplasia) que se mantiene durante gran parte del ciclo de vida en las especies de peces que alcanzan un gran tamaño corporal adulto, tanto como de la hipertrofia de las fibras musculares existentes, cuando se incluye en las dietas de O mykiss metionina (Alami et al, 2018).…”