Effect of protein levels on growth, feed utilization, nitrogen and energy budget in juvenile southern flounder, Paralichthys lethostigma

Abstract

A feeding trial with five crude protein levels (549, 513, 472, 445 and 399 g kg )1 ) was conducted to investigate the optimum protein level in diets of juvenile southern flounder (Paralichthys lethostigma). Budgets of nitrogen and energy were discussed. Fish (initial weight 32.9 ± 0.5 g fish )1 , mean ± SD) were fed the experimental diets to satiation twice daily for 61 days. Protein levels affected specific growth rate in wet weight (SGR W ) and protein (SGR P ) significantly. SGR W and SGR P were highest at 512.5 g kg )1 protein level. SGR W was positively correlated to growth nitrogen (GN), growth energy (GE), nitrogen digestibility, energy digestibility, amount of digestible nitrogen and amount of digestible energy. Faecal nitrogen (FN) and faecal energy (FE) were affected significantly with trends contrary to SGR W . The nitrogen budget was described by the equation 100CN ¼ 2.1FN + 34.4UN + 63.5GN (CN, nitrogen intake; UN, excretion nitrogen). The energy budget was 100IE ¼ 4.04FE +3.32UE + 54.35GE + 38.30ME (IE, gross energy intake; UE, excretion energy; ME, metabolizable energy). The average proportion of GE and ME in assimilated energy (AE) was described by the equation 100AE ¼ 58.65GE + 41.35ME. KEY WORDS

Effects of digestible protein levels in isonitrogenous diets on growth performance and tissue composition of juvenileAtractoscion nobilis

“…The increase of feed intake with decreasing dietary DP content observed in white seabass agrees with the findings in other fish species (Azevedo et al. 2004; Gao et al. 2005).…”

Effect of Different Dietary Protein and Lipid Levels on Growth Performance and Body Composition of Juvenile Southern Flounder, Paralichthys lethostigma, Reared in a Recirculating Aquaculture System

“…The dietary protein requirement of juvenile southern flounder is 50.3% using menhaden meal as protein source and a dietary lipid level of 14% when reared in a recirculating system (Gonzalez et al 2005). Gao et al (2005) suggested that the optimum protein level in diets for juvenile southern flounder was 51.2% using fish meal and casein–gelatin as protein sources when reared in a net cage system supplied with flow through system. In the present study, increasing lipid levels from 10 to 15% in a 50% protein diet had no significant affect on BWG reared in a recirculating system.…”

“…The methodology of spawning and larval rearing is well documented (Berlinsky et al 1996; Watanabe et al 2001; Daniels and Watanabe 2003; Watanabe et al 2006). One of the factors limiting commercial aquaculture production of southern flounder is the limited researches regarding the nutritional requirements (Alam and Watanabe 2005; Gao et al 2005; Gonzalez et al 2005).…”

“…Although the dietary protein requirement for southern flounder had been studied (Gao et al 2005), no information is available on utilization of lipid as an energy source at different dietary protein levels. The objective of this study was to determine the effects of various levels of lipid and protein in diets on growth and body composition of juvenile southern flounder.…”

Evaluacion de dietas comerciales en el crecimiento y su efecto en la composicion bioquimica muscular de juveniles de chita, Anisotremus scapularis (Tschudi, 1846) (Familia: Haemulidae).

“…En la nutrición de peces marinos carnívoros, la proteína (sus componentes en aminoácidos, AAs) es uno de los nutrientes más importantes debido a su aporte energético para el crecimiento y formación de nuevas estructuras tisulares (Limin et al, 2006), reportándose que de acuerdo a las especies, los niveles de proteína óptimos para un buen crecimiento se encuentran en el rango entre 40 y 55% de proteína (Boonyaratpalin, 1997;Gao et al, 2005). Asimismo, los lípidos juegan un rol importante en la nutrición, puesto que son precursores de componentes hormonales y de prostaglandinas, además como fuentes de ácidos grasos esenciales (AGE) (Tidwell et al, 2007).…”