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This experiment was conducted to investigate the effects of dietary black soldier fly (Hermetia illucens) larvae meal on growth performance, non-specific immunity and lipid metabolism of Litopenaeus vannamei. The control diet (FM) contained 25% fishmeal and then 10% (BSF10), 20% (BSF20) and 30% (BSF30) of fishmeal protein were replaced by black soldier fly larvae meal to formulate four isonitrogenous and isolipidic diets. Shrimps with an initial body weight of (0.88±0.01) g were fed four times daily for 7 weeks. Results showed that there were no significant differences in growth performance of shrimp fed BSF10 and BSF20 diets compared to FM group (P>0.05), but the growth performance of the shrimp in the BSF30 group significantly reduced (P<0.05). The whole shrimp crude lipid content was significantly lower in the BSF20 and BSF30 groups, and the hemolymph triglyceride and total cholesterol levels were significantly lower in the BSF30 group compared to FM group (P<0.05), but there were no significantly different in crude lipid of hepatopancreas among the four groups (P>0.05). The activities of hemolymph alanine aminotransferase and aspartate aminotransferase significantly decreased in the BSF10, BSF20 and BSF30 groups compared to FM group (P<0.05). The total antioxidant capacity of BSF20 group was significantly higher than that of the other groups, and superoxide dismutase activity of BSF10 group was significantly higher than that of FM group (P<0.05). The hepatopancreas acid phosphatase and alkaline phosphatase activities were significantly lower in the BSF30 group than that in the FM group (P<0.05). The lipase activity of BSF30 group was significantly lower than BSF10 group (P<0.05). The fatty acid synthase activity in BSF10 and BSF20 groups was significantly higher than that in FM group, the carnitine palmitoyl transferase activity in BSF20 group was significantly higher than the other three groups, and the activity of isocitrate dehydrogenase in BSF30 group was significantly higher than that in FM group (P<0.05). The activities of hemolymph lipid triglyceride lipase and α-ketoglutarate dehydrogenase in BSF10, BSF20 and BSF30 groups were significantly higher than those in FM group (P<0.05). To conclude, replacing 10% or 20% of fishmeal with black soldier fly larvae meal had no negative effect on the growth performance of Litopenaeus vannamei, improved the antioxidant capacity of shrimp and reduced the hemolymph glutamate transaminase and glutamic acid transaminase activities. The crude lipid of whole shrimp significantly reduced in BSF20 group, and when the replacing level reached to 30%, the activity of enzymes related to lipid catabolism and tricarboxylic acid cycle was significantly increased, which further promoted the lipid metabolism of shrimp. [ABSTRACT FROM AUTHOR]

The apparent digestibility coefficients (ADCs) of Tenebrio molitor meal (TMM), Hermetia illucens meal (HIM), Clostridium autoethanogenum protein (CAP), Methylococcus capsulatus meal (MCM), Chlorella vullgaris meal (CVM), Cottonseed protein concentrate (CPC) and Peruvian fishmeal (PFM) were determined in juvenile hybrid grouper (Epinephelus fuscoguttatus♀xEpinephelus lanceolatu♂). A basal diet (including 50% fishmeal) and seven test diets (700 g/kg of the basal diet and 300 g/kg of each test ingredient) were formulated with 0.1% yttrium oxide (Y2O3) as an inert marker. The juvenile hybrid groupers, with initial average body weight of (9.95±0.50) g, were randomly distributed into 0.3 m³ fiberglass tanks, each tank with 30 fish. The faeces samples were collected twice-daily by siphoning following feeding fish after five days of domestication. The ADCs of dry matter of seven test ingredients were ranked as CVM>TMM=CAP=CPC>HIM=MCM=PFM (P<0.05). CVM showed the highest ADCs of dry matter (DM), crude protein (CP) and most amino acids (including methionine and threonine) except crude lipids (CL), whereas HIM had the relatively lower ADCs of DM, CP and most amino acids except CL. CAP had a higher lysine digestibility than the other six test ingredients, and was only lower than CVM in the ADC of CP. The ADC of DM in PFM was significantly lower than that in CVM (P<0.05), and showed no differences with that in CAP (P>0.05). Besides, PFM showed a lower ADC of CP than the ADCs of CP in CVM, CAP and MCM (P<0.05), and showed a lower ADC of lysine than that in CAP as well as a lower ADC of threonine than those in CAP and CVM (P<0.05). Overall, this study showed the advantage of CVM and CAP among the seven protein sources on the digestibility of feed available in hybrid grouper. [ABSTRACT FROM AUTHOR]

A 56‐day feeding try was conducted to evaluate the effects of processed garlic known as black garlic (BG) fed at different inclusion levels (0 (BG0, control), 5 (BG0.5), 10 (BG1), 20 (BG2), 40 (BG4), and 80 (BG8) g/kg feed) on the growth, whole body composition, immune and antioxidant enzyme activities, gut microbiota and resistance to Vibrio parahaemolyticus infections in Litopenaeus vannamei (initial weight = 0.60 ± 0.001 g). The results revealed a significant improvement (p <.05) in the final weight, weight gain rate, specific growth weight, condition factor, protein efficiency ratio, survival rate, hepatosomatic index, and feed conversion ratio in the BG‐treated‐groups compared to the untreated. Correspondingly, the whole body proximate composition, immune, and antioxidant enzyme activities significantly improved in the treated groups than the untreated. Dietary BG had shaped the gut microbiota by significantly increasing (p <.05) the abundance of Phylobacterium, Ruegeria, and Pseudoalteromonas genera and decreasing (p <.05) the abundance of Vibrio genus than the control. Disease test with V. parahaemolyticus revealed significantly high (p <.05) resistance in the BG‐teated‐groups than the untreated. The BG8, BG4, BG2, BG1, and BG0.5‐treated groups respectively showed 72.1%, 62.8%, 55.8%, 41.9%, and 25.6% relative percentage survival. Dietary BG inclusion at 8% or at 80 g/kg feed could help improve shrimp growth and health. [ABSTRACT FROM AUTHOR]

The intensification of aquaculture to help kerb global food security issues has led to the quest for more economical new protein-rich ingredients for the feed-based aquaculture since fishmeal (FM, the ingredient with the finest protein and lipid profile) is losing its acceptability due to high cost and demand. Although very high in protein, castor meal (CM), a by-product after oil-extraction, is disposed-off due to the high presence of toxins. Concurrently, the agro-industrial wastes' consistent production and disposal are of utmost concern; however, having better nutritional profiles of these wastes can lead to their adoption. This study was conducted to identify potential biomarkers of CM-induced enteritis in juvenile hybrid-grouper ( Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) alongside their growth and distal intestinal (DI) health evaluation. A total of 360 fish (initial weight = 9.13 ± 0.01g) were randomly assigned into three groups, namely, fish-meal (FM) (control), 4% CM (CM4), and 20% CM (CM20). After the 56-days feeding-trial, the DI tissues of FM, CM4, and CM20 groups were collected for metabolomics analysis. Principal components analysis and partial least-squares discriminant-analysis (PLS-DA, used to differentiate the CM20 and CM4, from the FM group with satisfactory explanation and predictive ability) were used to analyze the UPLC-MS data. The results revealed a significant improvement in the growth, DI immune responses and digestive enzyme activities, and DI histological examinations in the CM4 group than the others. Nonetheless, CM20 replacement caused DI physiological damage and enteritis in grouper as shown by AB-PAS staining and scanning electron microscopy examinations, respectively. The most influential metabolites in DI contents identified as the potential biomarkers in the positive and negative modes using the metabolomics UPLC-MS profiles were 28 which included five organoheterocyclic compounds, seven lipids, and lipid-like molecules, seven organic oxygen compounds, two benzenoids, five organic acids and derivatives, one phenylpropanoids and polyketides, and one from nucleosides, nucleotides, and analogues superclass. The present study identified a broad array of DI tissue metabolites that differed between FM and CM diets, which provides a valuable reference for further managing fish intestinal health issues. A replacement level of 4% is recommended based on the growth and immunity of fish., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Amoah, Dong, Tan, Zhang, Chi, Yang, Liu, Yan, Yang and Zhang.)