Substitution effect of fish meal (FM) with chicken by-product meal (CBM) or meat meal (MM) in diets on growth, feed utilization, body composition, hematological chemistry, non-specific immune responses and amino and lipid acid profiles of juvenile olive flounder (Paralichthys olivaceus)

Abstract

1. Dietary substitution effect of fish meal with chicken by-product meal on growth, feed utilization, body composition, hematology and non-specific immune responses of olive flounder (Paralichthys olivaceus)

The present study examined the dietary substitution effect of CBM for FM on growth, feed utilization, body composition, hematology and non-specific immune responses of olive flounder, Paralichthys olivaceus. Six isonitrogenic and isolipidic experimental diets were prepared. The control (Con) diet contained 65% of FM. Ten, 20, 30, 40 and 50% of FM were replaced with CBM, referred to as the CBM10, CBM20, CBM30, CBM40 and CBM50 diets, respectively. A total of 400 juvenile fish averaging 14.7 g was distributed into 20 tanks (20 fish/tank) and fed triplicate groups of each diet, except for quadruplicate groups for the Con and CBM30 diets twice daily to satiation for 8 weeks. Arginine, phenylalanine and threonine content of the experimental diets increased with dietary increased substitution of FM with CBM. The experimental diets did not affect survival, weight gain, specific growth rate, feed consumption and feed utilization of fish. The chemical composition, whole body amino acid profiles, hematological variables and non-specific immune responses of fish were not changed by the experimental diets. These findings suggest that FM up to 50% of FM can be substituted with CBM without retardation in growth, feed utilization, hematology and non-specific immune responses of olive flounder.

2. Substitution effect of fish meal with meat meal in diets, feed utilization, hematological chemistry, non-specific immune responses and amino and lipid acid profiles of juvenile olive flounder (Paralichthys olivaceus) and challenge test against Streptococcus iniae

This study investigated the substitution effect of the graded levels of fish meal (FM) with meat meal (MM) on growth, feed consumption, feed utilization, chemical composition, hematological parameters, amino acid and lipid acid profiles of the whole body, and non-specific immune responses of olive flounder (Paralichthys olivaceus) and challenge test against Streptococcus iniae. A total of 525 juvenile fish were randomly distributed into 21, 50 L flow-through tanks. Seven experimental diets were prepared. Sixty five percent FM, 12% dehulled soybean meal and 1% krill meal were used as protein source in the control (Con) diet. The graded levels (10, 20, 40, 60, 80 and 100%) of FM were substituted with high quality of MM at the expense of wheat flour and soybean oil, referred to as the MM10, MM20, MM40, MM60, MM80 and MM100 diets, respectively. The experimental diets were isonitrogenous and isolipidic. All experimental diets were assigned to triplicate groups of fish. Fish were hand-fed to satiation for 8 weeks. Arginine content of the experimental diets tended to increase with increased substitution of FM with MM, except for the MM20 diet, but decrease for histidine, isoleucine, lysine, methionine except for the MM40 diet, threonine and valine except for the MM80 diet. ∑Saturates and ∑Monoenes contents of the experimental diets increased with increased substitution of FM with MM, but decreased for 18:2n-6, 18:3n-3, 20:5n-3, 22:6n-3 and ∑n-3 highly unsaturated fatty acids contents. The greatest weight gain (52.3 g/fish), specific growth rate (SGR) (3.39%) and feed consumption (49.3 g/fish) were obtained in fish fed the MM20 diet, followed by the MM10, MM40, Con, MM60, MM80 and MM100 diets, in that order. However, weight gain, SGR, feed consumption, protein efficiency ratio (PER) and protein retention of fish fed MM10 and MM40 diets were not different from those of fish fed the Con diet. Condition factor (CF) of fish fed the MM20 diet was higher than that of fish fed all other diets. The proximate composition of fish was not affected by the experimental diets. Amino acid profiles of the whole body of fish except for alanine, plasma chemistry and serum lysozyme and SOD activities were not affected by the experimental diets. No difference in survival of fish after S. iniae infection was observed during the 8-day post observation. In conclusion, FM up to 40% could be replaced with MM without deterioration of growth performance, SGR, feed utilization, non-specific immune responses and disease resistance of fish against S. iniae. The greatest weight gain, SGR, feed consumption, feed utilization (FER and PER) and CF were obtained in fish fed the MM20 diet.