| Summary: | This study aimed to evaluate effects of fish protein hydrolysate (FPH) supplementation in plant protein based diets for tiger puffer (Takifugu rubripes) on growth performance, intestinal peptide and amino acid transporters, and the expression of protein synthesis-related genes and texture parameters in muscle. Tiger puffer were fed negative and positive control diets with 280 and 400 g/kg fish meal (LFM and HFM) or test diets containing 52 and 104 g/kg FPH supplement as 60 and 120 g/kg fish meal (FPH6 and FPH12) substitute for 56 days. Each diet was randomly fed to triplicate groups of 30 fish per tank. Growth parameters (final body weight, weight gain and specific growth rate) in the LFM group were significantly lower than that of the HFM group (p < 0.05), while no differences in those growth results were observed among the FPH6, FPH12 and HFM groups (p > 0.05). Compared with the LFM group, the expressions of intestinal PepT1, EAAT3, PAT1 and y+LAT2 were up-regulated in the FPH12 and HFM groups, while intestinal CAT1 and B°AT1 mRNA levels showed opposite trends. To protein synthesis-related gene expression, compared with the LFM group, mRNA levels of TOR and S6k1 was not significantly affected by dietary treatments, but mRNA level of 4E-BP1 increased in the FPH12 group. Lower chewiness and higher adhesiveness were observed when FPH was supplemented to the diets. In conclusion, FPH supplementation in plant protein based diets demonstrated a sparing effect on fish meal, without the negative effect on the growth of tiger puffer.
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