Juvenile Pacific White Shrimp Research Articles

Replacement of fish meal with defatted black soldier fly (Hermetia illucens) in diet of Pacific white shrimp (Litopenaeus vannamei): growth, flesh quality and transcriptome

Abstract This study evaluated the impacts of replacing fish meal (FM) with defatted black soldier fly (Hermetia illucens; BSF) on the growth performance, flesh quality and transcriptome of Pacific white shrimp (Litopenaeus vannamei). In a diet containing 560 g/kg FM, BSF was used to replace 0%, 20%, 40%, 60%, 80% and 100% of dietary FM (BSF0, BSF20, BSF40, BSF60, BSF80 and BSF100). Thus, six isonitrogenous and isolipidic diets were prepared, and then fed to juvenile Pacific white shrimp (1.70 ± 0.10 g) for 60 days. In growth performance, the BSF20 group showed the similar FCR and WGR to the control group (), and the other four BSF groups presented significantly lower WGR and higher FCR than the BSF0 group (). The flesh chewiness and the contents of crude lipid, collagen and total amino acid in flesh were significantly decreased (), and flesh cooking loss, thawing loss was significantly increased when the replaced FM was ≥40% (). When the replaced FM reached 60%, the flesh hardness, heat-insoluble collagen content, shear force, body surface redness and the ratio of n-3/n-6 fatty acids were significantly lower (), while n-6 polyunsaturated fatty acid content and total free amino acid content in flesh were significantly higher than those of the BSF0 group (). Hepopancreatic samples were used for transcriptomic analysis, and a total of 1,456 differentially expressed genes (DEGs) were identified between the BSF groups and BSF0 group, which were mainly involved in growth-promoting, energy metabolism and antioxidant capacity key pathways and genes, including the cathepsin L, folate synthesis pathway, redox-related genes and glutathione metabolism pathway. In conclusion, in a diet containing 560 g/kg FM, BSF could successfully replace 20% of dietary FM, and higher FM replacement (≥40%) decreased the growth performance and flesh quality of Pacific white shrimp.

Effects of minimum dissolved oxygen setpoints for aeration in semi-intensive pond production of Pacific white shrimp (Litopenaeus vannamei)

Aeration is considered one of the most critical factors in shrimp farming as it affects the metabolism of shrimp and other living organisms within a pond. Maintenance of proper dissolved oxygen (DO) concentrations is critical, as low DO can cause stress, lower resistance to disease, and inhibit growth. Although the effects of single, short-term hypoxia events have been widely studied, little to no research has examined effects of repeated exposure to hypoxia during multiple diurnal cycles that shrimp may experience in aquaculture ponds. Even though the concept is simple, proper DO management is not simple. It is dependent on numerous factors and often based on anecdotal recommendations. The present trial was conducted to help elucidate the effects of DO management strategies on shrimp performance. The trial examined the effects of three different DO set points for automatic aeration on shrimp production and water quality parameters in earthen ponds. In sixteen earthen ponds (0.1 ha), juvenile Pacific white shrimp (⁓0.030 g) were stocked at a density of 25ind/m2. Minimal DO setpoints that activated automatic aeration in each of the treatments were 2.5, 3.5, and 4.5 mg O2/L, respectively. Shrimp were fed using the AQ1 passive acoustic monitoring system that was set to not feed while DO was below the threshold of a given treatment. Each of the treatments was applied to 5 ponds, except for treatment 1 (2.5 mg/L) which was applied 6 ponds as it was considered of higher risk. Shrimp growth performance and water quality indicators were monitored weekly. At the end of the 79–81-day trial, results showed that different aeration control treatments had no significant effect in terms of growth performance, feed inputs or productivity parameters. The final weight of the shrimp ranged between 33.3 and 33.6 g, with average final yields of 7500–8500 kg per ha. Nonetheless, mean electrical costs differed significantly between treatments, with higher DO setpoints treatments exhibiting a higher aeration cost with no discernible benefit. Water quality parameters showed no significant difference, except for morning and afternoon DO concentrations.

Pleionea litopenaei sp. nov., isolated from the gastric tract of juvenile Pacific white shrimp Litopenaeus vannamei.

A Gram-stain-negative, aerobic, rod-shaped and motile strain HL-JVS1T, was isolated from the gastric tract of a juvenile Pacific white shrimp. Molecular phylogenetic analysis based on 16S rRNA gene sequences of strain HL-JVS1T revealed its affiliation with the genus Pleionea, with close relatives including Pleionea mediterranea MOLA115T (97.5%) and Pleionea sediminis S1-5-21T (96.2%). The complete genome of strain HL-JVS1T consisted of a circular 4.4Mb chromosome and two circular plasmids (6.6 and 35.0kb) with a G + C content of 43.1%. The average nucleotide identity and digital DNA-DNA hybridization values between strain HL-JVS1T and the type strains of described Pleionea species were 69.7-70.4% and 18.3-18.6%, respectively. Strain HL-JVS1T grew at 10-40°C (optimum, 30°C) in the presence of 0.5 - 9.0% (w/v) sea salts (optimum, 2.0 - 2.5%), and at pH range of 5.5 - 10.0 (optimum, pH 6.5). The major fatty acids (> 10%) were summed feature 9 (iso-C17:1 ω9c and/or C16:0 10-methyl) (23.3%), iso-C16:0 (14.5%), iso-C11:0 3-OH (13.8%) and iso-C15:0 (11.0%). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminophospholipid, two unidentified aminolipids, and two unidentified lipids. The respiratory quinone was ubiquinone-8. The comprehensive phylogenetic, phylogenomic, phenotypic and chemotaxonomic results showed that strain HL-JVS1T is distinct from other Pleionea species. Hence, we propose strain HL-JVS1T as a novel species belonging to the genus Pleionea, for which the name Pleionea litopenaei sp. nov. is proposed with HL-JVS1T (= KCCM 90514T = JCM 36490T) as the type strain.

Dietary Lysophosphatidylcholine Improves the Uptake of Astaxanthin and Modulates Cholesterol Transport in Pacific White Shrimp Litopenaeus vannamei.

Astaxanthin (AST), functioning as an efficient antioxidant and pigment, is one of the most expensive additives in shrimp feeds. How to improve the uptake efficiency of dietary astaxanthin into farmed shrimp is of significance. The present study investigated the effects of lysophosphatidylcholine (LPC), an emulsifier, on dietary astaxanthin efficiency, growth performance, body color, body composition, as well as lipid metabolism of juvenile Pacific white shrimp (average initial body weight: 2.4 g). Three diets were prepared: control group, the AST group (supplemented with 0.02% AST), and the AST + LPC group (supplemented with 0.02% AST and 0.1% LPC). Each diet was fed to triplicate tanks, and each tank was stocked with 30 shrimp. The shrimp were fed four times daily for eight weeks. The AST supplementation improved the growth of white shrimp, while LPC further promoted the final weight of shrimp, but the whole-shrimp proximate composition and fatty acid composition were only slightly affected by AST and LPC. The LPC supplementation significantly increased the astaxanthin deposition in the muscle. The LPC supplementation significantly increased the shell yellowness of both raw and cooked shrimp compared to the AST group. Moreover, the dietary LPC increased the high-density lipoprotein-cholesterol content but decreased the low-density lipoprotein-cholesterol content in the serum, indicating the possible regulation of lipid and cholesterol transport. The addition of astaxanthin significantly up-regulated the expression of npc2 in the hepatopancreas compared to the control group, while the addition of LPC down-regulated the expression of mttp compared to the AST group. In conclusion, the LPC supplementation could facilitate the deposition of dietary astaxanthin into farmed shrimp and further enlarge the beneficial effects of dietary astaxanthin. LPC may also independently regulate shrimp body color and cholesterol transportation. This was the first investigation of the promoting effects of LPC on dietary astaxanthin efficiency.

Effects of hydroxyproline supplementation in low fish meal diets on collagen synthesis, myofiber development and muscular texture of juvenile Pacific white shrimp (Litopenaeus vannamei)

This experiment aimed to evaluate the impact of dietary hydroxyproline (Hyp) supplementation on the muscle quality of juvenile Pacific white shrimp (Litopenaeus vannamei) fed a low fishmeal diet. Six formulated diets included one high fishmeal (HF; 25% fishmeal content) and five low fishmeal diets (10% fishmeal content) with 0%, 0.2%, 0.4%, 0.6% and 0.8% Hyp (LF0, LF2, LF4, LF6 and LF8, respectively). Each diet was assigned to four replicates, and 40 shrimp (0.32 ± 0.00 g) per replicate were fed four times a day for 8 weeks. Dietary Hyp supplementation had little effects on growth performance, but increased the contents of Hyp, prolyl 4-hydroxylases (P4Hs), and collagen. The meat yield, springiness, hardness, chewiness, and cohesiveness of muscle were the highest in the LF4 group among the low fishmeal groups (P < 0.05). Cooking loss and freezing loss of muscle were the lowest in the LF4 group (P < 0.05). Dietary supplementation with 0.4% Hyp increased the myofiber density and decreased the myofiber diameter of muscle (P < 0.05). Supplementation of Hyp in the diet up-regulated the mRNA expression of smyhc5, smyhc15, col1a1, col1a2, igf-1f, tgf-β and tor and down-regulated the mRNA expression of smyhc1, smyhc2, smyhc6a (P < 0.05). Supplementation of Hyp in the diet up-regulated the protein expression of P-4E-BP1, P-AKT, AKT and P-AKT/AKT (P < 0.05). These results suggested that the addition of 0.4% Hyp to low fishmeal diets improved the muscle quality of L. vannamei.

Effect of dietary phytase and protease supplementation on the growth performance and apparent nutrient digestibility in juvenile Pacific white shrimp (Litopenaeus vannamei) fed fish meal–free and phosphorus limiting diets

Effect of dietary phytase and protease supplementation on the growth performance and apparent nutrient digestibility in juvenile Pacific white shrimp (Litopenaeus vannamei) fed fish meal–free and phosphorus limiting diets

Determination of optimal dietary valine concentrations for improved growth performance and innate immunity of juvenile Pacific white shrimp Penaeus vannamei

Determination of optimal dietary valine concentrations for improved growth performance and innate immunity of juvenile Pacific white shrimp Penaeus vannamei

Effects of the Supplementation of Lysophospholipid in Low‐Lipid Diets on Juvenile Pacific White Shrimp

The shortage of lipid sources has been a limiting factor of the aqua‐feed industry. Lysophospholipid (LPL) is a highly efficient lipid emulsifier, which may help improve lipid utilization efficiency and thus spare the dietary lipid. This study aimed to evaluate the effects of LPL on growth performance, fatty acid composition, and lipid metabolism of juvenile Litopenaeus vannamei (averagely, 2.4 g). Five diets were prepared: a control diet with 6.5% lipid, the control diet supplemented with 0.05% or 0.1% LPL (0.05% LPL and 0.1% LPL), a moderately low‐lipid (MLL) diet supplemented with 0.05% LPL (0.05% LPL‐MLL), and an extremely low‐lipid (ELL) diet supplemented with 0.1% LPL (0.1% LPL‐ELL). Each dietary group had triplicate tanks (30 shrimp in each tank). The feeding experiment lasted 8 weeks. Compared with the control group, the addition of 0.05% LPL promoted the growth by 9.95%; diet 0.05% LPL‐MLL resulted in a comparable growth to the control, but diet 0.1% LPL‐ELL tended to adversely affect the growth. Dietary LPL had little effect on the whole‐body proximate composition. The content of 18:2n−6 and 18:3n−3 was significantly higher in the 0.05% LPL group compared to the control. The 20:5n−3 content was the highest in the 0.05%LPL‐MLL group. In addition, the 0.05% LPL and 0.1% LPL group increased the plasma high‐density lipoprotein‐cholesterol content. Meanwhile, all LPL groups reduced the low‐density lipoprotein‐cholesterol content. The addition of LPL significantly regulated the messenger RNA (mRNA) expression of genes related to cholesterol homeostasis, such as ldlr, srb1, abca1, and abcg8. In conclusion, dietary supplementation with 0.05% LPL tended to promote shrimp growth and can spare 15% dietary lipid. However, when the dietary lipid content decreased from 6.5% to an extremely low level of 4.8%, dietary LPL was ineffective to spare lipids. This was the first study to validate the lipid‐sparing effect of dietary LPL in shrimp.

Different protein levels in a super-intensive culture of juvenile Pacific white shrimp (Litopenaeus vannamei) in biofloc systems during the early rearing phase

The determination of crude protein level in diets of aquatic organisms allows maximizing growth, decreasing feed costs and improving water quality. A nursery culture of Litopenaeus vannamei was carried out in superintensive biofloc systems using five diets with different protein levels (320 g kg-1 CP, 360 g kg-1 CP, 400 g kg-1 CP, 440 g kg-1 CP and 480 g kg-1 CP); each diet was used in quadruplicates. The experimental period lasted 35 days, and the shrimps (0.59± 0.001 g) were stocked at a density of 600 PL m-³, using 20 experimental units (50 L of useful volume). There were no significant differences in animal survival between treatments (p&gt;0.05). The animals fed with 480 g kg-1 presented higher final weight, SGR when compared to the treatments fed with 320 g kg-1 (p&lt;0.05). Furthermore, feeding shrimp with 32% CP diets results in a reduction in feed utilization and nutrient retention, thus increasing feed costs. Overall, the results show that it is possible to reduce the protein content of L. vannamei diets to up to 360 without affecting the zootechnical performance, survival and antioxidant capacity of the animals.

Effects of dietary supplementation of Achyranthes aspera extract on growth performance, digestibility, innate immunity, antioxidant capacity, and disease resistance of juvenile Pacific white shrimp, Penaeus vannamei

AbstractA supplemental effect of Achyranthes aspera extract (200 mg/kg phytosterol) in diets was evaluated for Pacific white shrimp (Penaeus vannamei) on growth performance, digestibility, innate immunity, antioxidant capacity, and disease resistance against Vibrio parahaemolyticus. A fish meal and soybean meal‐based control diet (Con; protein 38.0% and lipid 8.7%) was formulated and five other diets were prepared by adding A. aspera extract into Con diet to be 0.05, 0.1, 0.2, 0.4, and 0.8 mg phytosterol/kg concentration (designated as P05, P10, P20, P40, and P80, respectively). Three replicate groups of 30 shrimp (initial body weight, 0.40 ± 0.001 g) per diet were randomly assigned into 18 acrylic tanks (240 L) and fed one of the diets for 53 days. The growth performance and feed utilization efficiency were significantly higher in shrimp fed P20 and P80 diets than in shrimp fed Con and P10 diets. The dietary phytosterol supplementation improved non‐specific immune response, antioxidant capacity, and apparent digestibility coefficients of dry matter and protein of shrimp. The IGF‐binding protein gene expression was also upregulated with dietary phytosterol supplementation. During the challenge test, the disease resistance of shrimp was significantly enhanced against V. parahaemolyticus when shrimp were fed P20 diet. These results indicate that A. aspera extract could be used as a functional feed additive for the improvements in the growth performance, feed efficiency, innate immunity, antioxidant capacity, digestibility, and disease resistance of the shrimp. The optimum dietary inclusion level of the phytosterol seems to be 0.2–0.4 mg/kg diet.

Growth, Biochemical Characteristics, Flesh Quality, and Gut Microbiota of the Pacific White Shrimp (Penaeus vannamei) Fed a Defatted Superworm (Zophobas atratus) Larvae Meal.

This study evaluated the effects of defatted superworm (Zophobas atratus) larvae meal (DBWLM) as an alternative protein ingredient for juvenile Pacific white shrimp (Penaeus vannamei). Six isonitrogenous and isolipidic experimental diets were characterized by replacing 0%, 15%, 30%, 45%, 60%, and 75% fish meal (DBWLM0, DBWLM15, DBWLM30, DBWLM45, DBWLM60, and DBWLM75, respectively) with DBWLM on a w/w basis and feeding them to juvenile shrimp (0.34 ± 0.04 g) for 56 days. The results showed that the replacement of up to 75% fish meal by DBWLM had no negative effect on the growth performance of P. vannamei. The survival of shrimp in the DBWLM30 group was the highest, and the weight gain, specific growth rate, feed conversion ratio, condition factor, and apparent digestibility coefficients of dry matter in the DBWLM15 group were the highest. The substitution of DBWLM for fish meal significantly increased the elasticity of flesh, improved the total content of umami amino acids in flesh (aspartic acid, glutamic acid, glycine, and alanine), promoted lipid metabolism in shrimp, and reduced serum lipid levels. With the increase in DBWLM level, serum acid phosphatase, alkaline phosphatase activity, and intestinal inflammatory gene expression (IGF-1 and IL-6) were inhibited, malondialdehyde content decreased, and total antioxidant capacity level and superoxide dismutase activity increased significantly. Histological sections of the hepatopancreas showed that when 60% or more fish meal was replaced, the hepatopancreas atrophied and had irregular lumen distortion, but the cell membrane was not damaged. Microbiome analysis showed that the abundance of Bacteroidetes and Firmicutes increased and the abundance of Proteobacteria decreased in the DBWLM replacement group, and it was rich in "metabolism"-related functional pathways. It is worth mentioning that the expression of amino-acid-related enzymes was upregulated in the DBWLM15 and DBWLM30 groups, and the DBWLM75 group inhibited the biosynthesis of steroids and hormones. To conclude, the replacement of 15%-45% fish meal with DBWLM can result in better growth and immune status, improved meat elasticity, and reduced inflammation in P. vannamei. However, it is recommended that the replacement level should not exceed 60%, otherwise it will cause atrophy of hepatopancreas cells.

Dietary bile acids promote sterol metabolism, bile acids enterohepatic circulation, and apoptosis in juvenile Pacific white shrimp (Litopenaeus vannamei)

Bile acids have an important role in the growth and sterol metabolism of shrimp. The aim of this study was to elucidate the effects of bile acids supplementation in the low fishmeal diets on sterol metabolism, bile acids enterohepatic circulation, bile acid profile, and apoptosis in Pacific white shrimp Litopenaeus vannamei. Six diets were formulated in this experiment, HFM diet (25% fishmeal), LFM diet (10 % fishmeal), and LFM supplemented with four levels (0.15, 0.3, 0.6, 0.9 g kg−1) of bile acids, which were LBA1, LBA2, LBA3, LBA4, respectively. Soy protein concentrate and cottonseed protein concentrate blend was used to replace fishmeal of 60 %. After 50 days of feeding trial, the shrimp fed the LBA4 diet showed significantly increased final body weight than that fed the LFM diet (P < 0.05). In the sterol metabolism, the shrimp fed the LBA1 diet was significantly increased the HMG-CoA reductase membrane form (hmgcr) and Niemann-Pick type C-2-like protein (npc2) expression compare with that fed the LFM diet, shrimp in LBA2 group was significantly increased the related genes expression [hmgcr and NPC intracellular cholesterol transporter 1-like (npc1)] than those in the LFM group of hepatopancreas (P < 0.05). In the lipid metabolism, the shrimp in LBA2 group was significantly increased the carnitine palmitoyltransferase-1 (cpt-1) and AMP-activated protein kinase (ampk) expression than that in the LFM group, shrimp in the LBA3 group was significantly increased the fatty acid binding protein fatty acid (fabp) expression than that in the LFM group (P < 0.05). In the bile acids metabolism, the multidrug resistance-associated protein 1-like (mrp2), multidrug resistance-associated protein 2-like (mrp3) and solute carrier family 22 member 7-like (oatp) expressions were significantly increased in LBA1 and LBA2 groups than those in the LFM group of hepatopancreas, organic solute transporter subunit alpha-like (ostα), mrp2, and acyl-coenzyme A thioesterase 1-like (baat) expressions were significantly up-regulated in LBA4 group than those in the LFM group of intestine (P < 0.05). Supplementary bile acids in the diet could decrease the apoptosis-related protein expression (BCL-2 and CASPASE3) compare with the shrimp fed low fishmeal diet (P < 0.05). The concentration of beta MCA in hemolymph bile acids profile increases with bile acids supplementation. The results showed that bile acids enhanced growth performance, promoted sterol metabolism, enhanced enterohepatic circulation, and reduced apoptosis in shrimp on low fishmeal diets. Data availability statementThe data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical.

Aspergillus niger confers health benefits and modulates the gut microbiota of juvenile Pacific white shrimp (Penaeus vannamei) under farming conditions

IntroductionThe fungus Aspergillus niger is found to be predominant in the body of Pacific white shrimp (Penaeus vannamei); however, its role in shrimp’s health has not been explored. This study aimed to evaluate the influences of A. niger on growth, antioxidative activity, immune response, and gut microbiota of juvenile Pacific white shrimps under farming conditions.MethodsShrimps (2.30±1.05 g) were fed diets supplemented with 0 (control), 1.5 (A1.5), or 3.0 g/kg diet of A. niger (A3.0) for one month. At the end of the study, the growth, antioxidant enzyme activity and immune parameters, and gut microbiota in shrimps fed with different experimental diets were analyzed.ResultsThe results showed a significant increase in weight gain, specific growth rate, and length gain of shrimps in A1.5, compared with other groups (P&amp;lt;0.05). With the exception of lysozyme in both A1.5 and A3.0, which were lower than in the control, the activity of superoxide dismutase (SOD), catalase, acid phosphatase, alkaline phosphatase, and phenol oxidase was higher than those in the control. Gene expressions of SOD, anti-lipopolysaccharide factor-ALF1, and ALF2 (in A1.5 and A3.0) and nitric oxide synthase, penaeidin-PEN2 (in A1.5) and PEN3 and PEN4 (in A3.0) were significantly up-regulated compared to the control (P&amp;lt;0.05). The addition of A. niger increased diversity and separated the microbial community in the gut of shrimps. At the phylum level, Firmicutes and Bacteroidota were dominant, and Proteobacteria was less abundant in the A1.5 and A3.0, as compared to the control. At the genus level, the relative abundance of Vibrio, Marivita, and Roseobacter was increased but Ruegeria was decreased in A1.5 and A3.0 when compared to the control. The genera Edwardsiella, Clostridium sensu stricto 1, and Shimia in the A1.5 were higher than in the control.DiscussionThese findings demonstrated the beneficial effects of A. niger on growth, health, and changes in the gut microbiota in shrimps under farming conditions. The recommended concentration of A. niger in the diet for shrimps is 1.5 g/kg diet.

Dietary inositol improves growth and health status by regulating the barriers function of hemolymph and intestine of juvenile Pacific white shrimp (Litopenaeus vannamei)

The present study aimed to evaluate the effects of dietary inositol level on the growth performance and barriers function of hemolymph and intestine of Litopenaeus vannamei. Six isonitrogenous and isolipidic diets were formulated with analyzed inositol levels being 0.86 (basal diet), 1.34, 1.40, 2.30, 3.88, and 7.50 g kg−1, respectively. The results indicated that appropriate dietary inositol could improve the growth performance of Litopenaeus vannamei. The optimal dietary inositol requirement was 1.44 g kg−1 according to broken-line regression analysis with the WGR as the evaluation index. The activities of non-specific immune enzymes (SOD, ACP, ALP and NOS) in hemolymph and the expression levels of genes involved in the Toll signaling pathway (toll, pelle and traf6) in hemocyte of shrimp fed diet containing 1.40 g kg−1 inositol significantly higher than those in shrimp fed diet containing 0.86 g kg−1 inositol, and the activities of PO and SAHR in hemolymph and the expression levels of genes involved in immune enzymes (Mn-sod, Cu/Zn sod, acp, akp and po) in hemocyte of shrimp fed diet containing 1.40, 2.30, 3.88 and 7.50 g kg−1 inositol significantly higher than those in shrimp fed diet containing 0.86 g kg−1 inositol, suggesting that appropriate dietary inositol can improve hemolymph immunity by increasing the activities of antioxidant and immune enzymes in the hemolymph. In addition, the intestinal VH and the expression levels of genes involved in intestinal health (zo-1, cyclC, tgfβ and il2) in shrimp fed diet containing 1.40 g kg−1 inositol were the highest. Meanwhile, the inositol content, VW, and the expression levels of genes involved in the IMD pathway (imd) and anti-lipopolysaccharide factor (alf) in the intestine were significantly correlated with dietary inositol level. These results suggested that appropriate inositol can improve intestinal health by improving intestinal morphology and the expression of health-related genes. Although dietary inositol had no significant effect on the microbial composition spectrum diversity in the hemolymph and intestine of L. vannamei, it contributed to increasing the abundance of beneficial bacteria and decreasing the abundance of opportunistic pathogens. KEGG analysis showed that dietary inositol level had significantly positive effects on multiple immune and metabolic pathways. In conclusion, dietary appropriate inositol enhanced hemolymph homeostasis and host immune defense by improving the barrier function of immune and microbial in hemolymph and improved the intestine health status by enhancing the barrier function of physical, immune and microbial in intestine.

Benzoic Acid Inclusion Effects on Health Status and Growth Performance of Juvenile Pacific White Shrimp Penaeus vannamei

AbstractOrganic acids and their salts are used as additives in aquafeeds, as their participation in some metabolic pathways and energy generation in organisms increases the nutritional value. Benzoic acid (BA; C6H5‐COOH), a white crystalline substance with a chemical structure that contains carboxylic acid attached to a benzene ring, is naturally found in plant and animal tissues. It is one of the most used organic acids due to its antifungal properties, and it acts as a preservative for a variety of human consumption products. Additionally, it demonstrates health and growth benefits when included in feeds by modifying the energy metabolism, microbiota, and intestinal tract morphology. Information on BA inclusion in aquatic food is rare, and such information for Pacific white shrimp Penaeus vannamei is nonexistent. This study evaluated the effects on growth, survival, feed conversion ratio, energy content, and health status (through lipid quantification in the hepatopancreas, histological examination, and salinity stress tests) of Pacific white shrimp juveniles by including BA at different concentrations (0.0, 1.0, 1.5, and 2.0 g/kg) in a commercial feed. Diets with BA inclusion produced significant differences in the hepatosomatic index, hepatopancreas lipid content, and histopathological index value (reflecting damage to the hepatopancreas and antennal gland atrophy) at all BA concentrations. The lowest survival obtained was 94.44% at a BA concentration of 1.0 g/kg. The feed conversion ratio was in accordance with the range established by the Food and Agriculture Organization of the United Nations except for values obtained at 0 g/kg. Calorimetric analysis and BA detection in muscle revealed no significant differences between concentrations. Due to the results obtained in this study, the evaluated inclusions of BA are not recommended for use in juvenile Pacific white shrimp diets.

The effects of dietary myo-inositol on growth and physiological, biochemical, and molecular responses in the Pacific white shrimp Litopenaeus vannamei

Myo-inositol serves as an essential nutrient in many animal species. However, the optimal requirements of myo-inositol and the mechanisms by which myo-inositol is involved in nutritional regulation in crustaceans are unclear. An 8-week trial was conducted to comparatively evaluate the effects of 6 levels of dietary myo-inositol (20, 528, 1030, 2060, 3180 and 4235 mg/kg diet) on growth performance, body composition, serum metabolite composition, hepatopancreatic metabolite content, and digestive enzyme activity in juvenile Pacific white shrimp Litopenaeus vannamei (0.78 ± 0.039 g). The weight gain and conditioning factors of shrimp fed myo-inositol were significantly higher than those of the 20 mg/kg myo-inositol group. The maximal hepatosomatic index was found in the 1030 mg/kg myo-inositol group. On the other hand, serum triglyceride, total cholesterol, and low-density lipoprotein contents in the control group were significantly lower than those in the other groups, and glucose content in the hepatopancreas in the control group was significantly lower than that in the 2060 and 3180 mg/kg myo-inositol groups. Metabolome and transcriptome analyses revealed that myo-inositol significantly affected glycerophospholipid metabolism, transport and catabolism in lysosomes, pancreatic secretion, and bile secretion pathways. The highest growth was achieved with the inclusion of 528 mg/kg dietary myo-inositol. This study has suggested that myo-inositol may promote growth in L. vannamei by improving lipid utilization.

Effect of feed enzymes and functional immunostimulants supplementation on growth performance and overall health of postlarvae and juvenile Pacific white shrimp, Penaeus vannamei, fed soybean‐based diets

AbstractSoybean meal (SBM) is widely used in shrimp feed agro‐industry as a fish meal (FM) replacement. However, high levels of SBM may compromise animal health as a result of nutrient imbalance. This study aimed to investigate the effects of feed enzyme combination (a mixture of 6‐phytase, serine protease, and endo‐1,3(4)‐β‐glucanase) and functional immunostimulant combination (a mixture of brewer's yeast, nucleotides, vitamin C, and vitamin E) in improving the overall health of Pacific white shrimp fed soybean‐based diet. Four diets were formulated with different amounts of SBM, FM, and poultry meal (PM): 0% SBM (with 25% FM and 12.6% PM), 30% SBM (with 12.5% FM and 5.7% PM), 30% SBM plus 0.045% feed enzymes, and 30% SBM plus 0.1% functional immunostimulants. The postlarvae were fed the test diets for 45 days. Then, the body weight, survival, FCR, Vibrio spp. count, and immune responses were analyzed. The resistance of shrimp to Vibrio parahaemolyticus infection was also evaluated. The results suggest that the diet with 30% SBM was deleterious to the shrimp's health. Feed enzymes and functional immunostimulant supplements improved overall performance, immune function, and resistance to V. parahaemolyticus infection of shrimp fed the diet containing 30% SBM compared with the 30% SBM diet without feed supplements.

Comparative study on the effects of crystalline L-methionine and methionine hydroxy analogue calcium supplementations in the diet of juvenile Pacific white shrimp (Litopenaeus vannamei).

An 8-week feeding trial was conducted to evaluate the effects of L-methionine and methionine hydroxy analogue calcium (MHA-Ca) supplements in low-fishmeal diet on growth performance, hepatopancreas morphology, protein metabolism, anti-oxidative capacity, and immunity of Pacific white shrimp (Litopena eus vannamei). Four isonitrogenous and isoenergetic diets were designed: PC (203.3g/kg fishmeal), NC (100g/kg fishmeal), MET (100g/kg fishmeal +3g/kg L-methionine) and MHA-Ca (100g/kg fishmeal +3g/kg MHA-Ca). White shrimp (initial body weight 0.23 ± 0.00 g, 50 shrimp per tank) were allocated to 12 tanks and divided among 4 treatments in triplicates. In response to L-methionine and MHA-Ca supplementations, the shrimp exhibited higher weight gain rate (WGR), specific growth rate (SGR), condition factor (CF), and lower hepatosomatic index (HSI) compared to those fed the NC diet (p < 0.05). The WGR and SGR of shrimp fed L-methionine and MHA-Ca showed no difference with those in the PC diet (p > 0.05). Both of L-methionine and MHA-Ca supplementary diets significantly decreased the malondialdehyde (MDA) levels of shrimp when compared with the NC diet (p < 0.05). L-methionine supplementation improved the lysozyme (LZM) activity and total antioxidant capacity (T-AOC) of shrimp, while the MHA-Ca addition elevated the reduced glutathione (GSH) levels in comparison with those fed the NC diet (p < 0.05). Hypertrophied blister cells in hepatocytes were observed in shrimp fed the NC diet, and alleviated with L-methionine and MHA-Ca supplementations. Shrimp fed the MET and MHA-Ca diets had higher mRNA expression levels of target of rapamycin (tor) than those fed the NC diet (p < 0.05). Compared to the NC group, dietary MHA-Ca supplementation upregulated the expression level of cysteine dioxygenase (cdo) (p < 0.05), while L-methionine supplementation had no significant impact (p > 0.05). The expression levels of superoxide dismutase (sod) and glutathione peroxidase (gpx) were significantly upregulated by L-methionine supplemented diet in comparison with those in the NC group (p < 0.05). Overall, the addition of both L-methionine and MHA-Ca elevated the growth performance, facilitated protein synthesis, and ameliorated hepatopancreatic damage induced by plant-protein enriched diet in L. vannamei. L-methionine and MHA-Ca supplements enhanced anti-oxidants differently.

Brown sugar addition enhanced nutrient removal rates, growth performance, and bacterial community in a rice straw-based biofloc shrimp culture system

A 30-day culture trial was executed to ascertain the effects of brown sugar addition on nutrient removal, feed conversion ratio, growth performance, and microbial community in a rice straw-based biofloc shrimp system. Twelve indoor experimental barrels were supplied with juvenile pacific white shrimp (Litopenaeus vannamei) with a preliminary mean weight of ∼1.08 ± 0.35 g. The experimental groups comprised four biofloc treatments labeled as (Control-CT, SG1, SG2, and SG3), each with three replicates. The SG groups were the treatments with varying amounts of carbon source (brown sugar) addition. Each experimental barrel was stocked with 100 juvenile shrimps. To maintain the carbon: nitrogen ratio, brown sugar was added daily in varying amounts in the SG treatments but not in the control group (CT). The results demonstrated that the ammonium and nitrite‑nitrogen concentrations in the SG3 (0.45 and 0.34 mg/L) and SG2 (0.58 and 0.43 mg/L) groups were significantly (p < 0.05) lower than the Control (1.18 and 0.88 mg/L). Also, the highest nutrient removal rates for ammonium nitrogen (80%) and nitrite nitrogen (83.79%) were observed in the SG3 treatment. In addition, the SG2 group's feed conversion ratio (0.66) was statistically (p < 0.05) lower than the CT group's (0.83). Compared to the control setup (86%), the SG treatments recorded shrimp survival rates of over 90%. Furthermore, our results revealed that the most dominant microbial phyla in all treatments were Proteobacteria (71.60%), Bacteroidetes (26.60%), Actinobacteria (18.53%), Planctomycetes (8.30%), and Verrucomicrobia (2.40%) which played a significant role in nutrient cycling and promoting water quality. Overall, our study highlighted an innovative ecological farming system that recycles agricultural waste, minimizes inorganic nitrogen levels, and serves as an in-situ food source for sustainable shrimp production.

Growth performance and nutritional impact of Moringa oleifera leaf extract as supplemental diets in the juvenile pacific white shrimp (Penaeus vannamei)

Moringa (Moringa oleifera) is widely recognized for its potent medicinal properties and immunostimulant effects. This study aimed to investigate the impact of a hot water extract of moringa leaves on the growth performance, feed conversion ratio, and survival of pacific white shrimp, Penaeus vannamei. Four different diets were used in this experiment, each containing varying levels of moringa leaf extract: 0, 2.5, 5, and 7.5 g/kg of the diet. A total of 1,200 shrimp, with an initial body weight of 0.01 g/individual, were carefully selected to ensure they were free from Vibrio infestation. One hundred shrimp were placed in each circular tank, with a volume of 750 L or 133 individuals per cubic meter. The shrimp were fed the diets four times daily, with a protein content ranging from 13% to 39%, over a period of 30 days. The results of the study revealed that the growth performance and survival rate of the shrimp in the groups that were fed diets supplemented with moringa were significantly higher than those in the control group (without moringa supplementation). The highest growth performance, in terms of specific growth rate, weight gain, and final weight, was observed in the groups of shrimps that were fed diets containing either 2.5 g or 5 g of moringa leaf extract per kilogram of the diet (p&lt;0.05). Furthermore, the diet containing 2.5 g of moringa leaf extract per kilogram resulted in the highest survival rate compared to the other treatment groups. Therefore, it can be concluded that the optimal level of moringa in the diet of vannamei shrimp is 2.5 g/kg of the diet.