Untitled

Abstract

This trial was conducted to investigate the dietary arginine requirement in two sizes of blunt snout bream (Megalobrama amblycephala). Six isonitrogenous and isoenergetic (34% crude protein) diets containing graded levels of arginine from 8.3 to 33.6 g kg -1 . Triplicates of 30 fishes (body weight 52.50±0.18g) of size I or 20 fishes (body weight 101.85±1.85g) of size II were fed with one of six experimental diets. Specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and weight gain (WG) significantly increased with the increase of arginine levels from 8.3 to 23.5 g kg -1(size I) or from 8.3 to 18.1 g kg -1(size II), and thereafter, kept decrease. The alanine aminotransferase (ALT) was significantly decreased with increase in dietary arginine levels from 8.3 to 23.5 g kg -1in size I or 8.3 to 18.1 g kg -1 of the size II (P<0.05). Urea content first significantly increased (P<0.05), and showed the same trend in two sizes. Meanwhile, plasma arginine concentration of two sizes significantly increased with increasing dietary arginine from 8.3 to 23.5 g kg -1 (P<0.05), and significantly lower lysine content in plasma was observed in fish fed diets with arginine levels from 8.3 to 23.5 g kg -1 (P<0.05). Broken-line regression model analysis relation on the basis of SGR, the optimal dietary arginine requirement could be 20.3 g kg -1 in size I, and 17.9 g kg -1 in size II of dry matter, respectively. The results may explain the adverse effects of a deficient or an excess dietary arginine level on growth and health of fish in future. Furthermore, the present study also suggests that an optimum dietary arginine could play an important role in improving growth, and maintaining health for different size of fish, which would be useful in developing amino acid balanced commercial feeds for blunt snout bream.

Immunomodulation of Tumor Microenvironment by Arginine-Loaded Iron Oxide Nanoparticles for Gaseous Immunotherapy

“…As shown in Figure d,e, when the pH value decreased from 7.4 to 5.0, hydrodynamic sizes and zeta potentials of LP Fe 3 O 4 NPs increased from 229.4 ± 5.0 to 318.0 ± 10 nm and −31.1 ± 0.6 to −15.4 ± 0.7 mV, respectively, indicating that PAA has been protonated to loosen the polymer shell under acidic conditions, which can be used for releasing l -Arg. Then, the released l -Arg amount could be assessed by naphthol-diethyl hydrazine . As confirmed in Figure f, nearly 72.9% of l -Arg was released from LP Fe 3 O 4 NPs after 8 h of incubation at pH 5.0, while only 48.67 and 38.9% of l -Arg were released at pH 6.0 and 7.4, respectively.…”

“…The concentration of L-Arg in the supernatant was analyzed by the naphthol-diethyl hydrazine method. 31 Briefly, the indicator aqueous solution was prepared to contain NaOH (40 mg mL −1 ), 1-naphtholpropanol (80 mg mL −1 ), and diacetyl-propanol (0.5 μL mL −1 ). 20 μL of supernatant was mixed with 130 μL of indicator solution, and then, the absorbance of the above mixture was detected at 540 nm after 20 min incubation with a SpectraMax M5 microplate reader.…”

“…25 mg of LP Fe 3 O 4 NPs was suspended in 5 mL of PBS (pH = 7.4, 6.0, and 5.0) and centrifuged at different time points. The concentration of l -Arg in the supernatant was analyzed by the naphthol-diethyl hydrazine method . Briefly, the indicator aqueous solution was prepared to contain NaOH (40 mg mL –1 ), 1-naphthol-propanol (80 mg mL –1 ), and diacetyl-propanol (0.5 μL mL –1 ).…”

Effect assessment of tea polyphenols extracted from green tea on growth performance, immunity and gut microbiota &amp; metabonomics in juvenile hybrid sturgeon (Acipenser baerii♀ × A. schrenckii♂)

“…The following variables were calculated [33] Survival rate (SR, %) = 100 × nal sh number / initial sh number.…”