Fish meal (FM) is considered as an important ingredient in aquafeed production due to its high-quality protein with well-balanced essential amino acids and many other nutrients (Hertrampf & Piedad-Pascual, 2000). Over time, researchers have focused on finding suitable FM alternatives and found some successful plant protein sources that function up to some extent in feed formula-

This study was conducted to examine digestibility of insect meals for Pacific white shrimp (Litopenaeus vannamei) and their utilization as fish meal substitutes. The tested insect meals were mealworm, silkworm, black soldier fly, rice grasshopper, two-spotted cricket, dynastid beetle and white-spotted flower chafer. Apparent digestibility coefficients of the tested insect meals were 83–89% for protein, 91–98% for lipid, 84–90% for energy, 77–81% for dry matter, 28–36% for chitin, 76–96% for amino acids and 89–93% for fatty acids. The amino acid availability of insect meals was high in taurine (93–96%), arginine (91–95%) and lysine (90–95%). Availability of fatty acids were 89–93% for saturated fatty acids, 90–93% for monounsaturated fatty acids and 88–93% for polyunsaturated fatty acids. For a feeding trial, a control diet was formulated using 27% tuna byproduct meal as a fish meal source and seven other diets were prepared replacing 10% tuna byproduct meal in the control diet with each insect meal. Triplicate groups of shrimp (initial body weight: 0.17 g) were fed the diets for 65 days. The growth performance was significantly improved when the shrimp were fed black soldier fly or dynastid beetle included diet. Dietary supplementation of insect meals significantly improved non-specific immune responses and antioxidant enzyme activity in the shrimp. These results indicate that the tested insect meals have high potentials to be used as a protein source that could replace fish meal in diets for the shrimp.

This study was conducted to evaluate the supplemental effects of esterified monobutyrin (MB) and tributyrin (TB) on growth performance, feed efficiency, digestibility, innate immunity, antioxidant status and disease resistance of Pacific white shrimp, Litopenaeus vannamei. A basal (control) experimental diet was formulated without MB or TB, and four other diets were prepared by supplementing powder forms of MB at 2 and 4 g/kg (0.2% and 0.4%) or TB at 1 and 2 g/kg (0.1% and 0.2%) (designated as MB0.2, MB0.4, TB0.1 and TB0.2, respectively). Quadruplicate groups of shrimps were hand‐fed with one of the diets four times daily for 53 days. Shrimp fed MB or TB diets showed significantly higher growth performance, feed utilization, phagocytosis and glutathione peroxidase activity than shrimp fed the control diet. Increased digestibility of dietary protein, lipid and dry matter was found in shrimp fed MB‐ or TB‐supplemented diets. Relative mRNA expression levels of IGF‐binding protein and prophenoloxidase gene were significantly increased in shrimp fed MB‐ or TB‐supplemented diets than in shrimp fed the control diet. The results of a challenge test with Vibrio harveyi showed that the disease resistance of shrimp can be significantly enhanced against V. harveyi when they were fed TB0.2 diet. The results of this study indicate that dietary supplementation of 2 g/kg MB or 1–2 g/kg TB can improve growth and feed efficiency, innate immunity, antioxidant activity, digestibility and disease resistance of L. vannamei.

Background: Taurine is a conditional essential amino acid for fish. A study was conducted to investigate the compensating effect of supplemental taurine in diets for red seabream (Pagrus major) on impaired growth performance by fish meal (FM) replacement with soybean meal (SM) at low water temperature (14.15 ± 1.95°C). Methods: A FM-based diet was considered as a high FM diet and three other experimental diets were formulated to replace FM with SM by 20, 35, or 50% (HFM, SM20, SM35, or SM50, respectively) without taurine and other four diets were formulated by adding 1% taurine to the diets (HFM-T, SM20-T, SM35-T, or SM50-T, respectively). Triplicate groups of fish (108.9 ± 1.58 g/fish) were distributed into 24 polyvinyl circular tanks (215 L) with 20 fish per tank and fed one of the diets to satiation for 20 weeks. Results: Growth performance and feed utilization of red seabream were significantly improved by the dietary taurine supplementation. SM20-T and SM35-T diets increased fish growth that are comparable to HFM diet. Feed intake, feed conversion ratio, and protein efficiency ratio of fish fed SM20-T and SM35-T diets were not significantly different from those of HFM group. Dietary taurine supplementation in each FM replaced group numerically increased innate immunity of the fish. Lysozyme and superoxide dismutase activities were significantly decreased in fish fed SM35, SM50, and SM50-T diets compared to those of fish fed HFM diet while they were not significantly lower in SM20, SM20-T, SM35, and SM35-T groups. Glutathione peroxidase activity was significantly lower in fish group fed SM50 diet while SM50-T group did not significantly lower compared to that of HFM group. The relative expression level of hepatic IGF-1 mRNA was improved in fish fed taurine-supplemented diets compared to their respective SM diets. Conclusions: Growth performance and feed utilization of red seabream can be accelerated or restored by 1% taurine supplementation when they are fed high level of SM up to 35% in diets during low water temperature season.

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