Growth Performance Of Shrimp Research Articles

Effects of dietary chenodeoxycholic acid supplementation in a low fishmeal diet on growth performance, lipid metabolism, autophagy and intestinal health of Pacific white shrimp, Litopenaeus vannamei

An 8-week feeding trial was conducted to evaluate the effects of chenodeoxycholic acid (CDCA) on growth performance, body composition, lipid metabolism, and intestinal health of juvenile white shrimp, Litopenaeus vannamei fed a low fishmeal diet. Four practical diets were formulated: HFM (25% fishmeal), LFM (15% fishmeal), LB1 (LFM + 0.04% CDCA), LB2 (LFM + 0.08% CDCA). Each diet was assigned to four tanks with forty shrimp (initial weight 0.33 ± 0.03 g) per tank. The results indicated that the growth performance of shrimp were similar between the four groups; the crude lipid content of shrimp fed the LB2 diet was significantly lower than those fed the HFM diet (P < 0.05). The lipase activity content in hepatopancreatic were significantly higher in the two CDCA supplemented groups than that in LFM group; the contents of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol in hemolymph were significantly lower in LFM group, LB1 group and LB2 group than that in HFM group (P < 0.05). The shrimp fed LB1 diet was significantly decreased the intestinal expression levels of tube than those fed in HFM diet; the intestinal gene expression of imd and toll were significantly lower in LB2 group than those in HFM group (P < 0.05). The results of hepatopancreas gene expression suggest that shrimp fed the LFM diet showed significantly upregulated expression levels of sterol regulatory element-binding protein (srebp), acetyl-CoA carboxylase (acc), and carnitine palmitoyltransferase 1 (cpt-1) than those fed the HFM diet; shrimp fed the LB1 diet showed significantly upregulated expression levels of srebp, acc, and AMP-activated protein kinase (ampk) than those fed the HFM diet; shrimp fed the LB2 diet had higher expression levels of srebp, acc, and cpt-1 than those fed the HFM diet (P < 0.05). In the hepatopancreas, the shrimp fed the LFM diet shown significantly up-regulated the expression levels of beclin1 compared to those fed HFM diet; the expression levels of autophagy-related protein13 (atg3), autophagy-related protein 12 (atg12) of in shrimp fed the LB1 diet were significantly higher than those fed the HFM diet; and the expression levels of autophagy-related protein13 (atg13), beclin1, atg3, atg12, autophagy-related protein 9 (atg9) of shrimp fed LB2 diet were significantly higher than those fed the HFM diet (P < 0.05). The atg3 in intestine of shrimp fed the LB2 diet were significantly higher than those fed the HFM diet (P < 0.05). Intestinal mucous fold were damaged, hepatic tubules were disorganized and B cells appeared to be swollen in LFM group. The fold height and width of shrimp fed the diets supplemented with CDCA increased significantly than those fed the LFM diet (P < 0.05), the hepatic tubules were neatly arranged, and R cells increased. In conclusion, supplementary CDCA in a low fishmeal diet promoted lipid metabolism, enhanced autophagy of shrimp, also improved the health of the intestine and hepatopancreas.

Environmental factors of rearing water and growth performance of shrimp (Penaeus vannamei) in a microalgal monoculture system

Microalgal ecological regulation technology uses beneficial planktonic microalgae in water their physiological and ecological characteristics, and then to regulate and optimize the water ecological environment. To identify high-quality algal strains suitable for microalgal ecological regulation technology and analyse the ecological regulation mechanism of microalgae in shrimp culture, Nannochloropsis oculata and Thalassiosira sp. preliminarily were used as the research objects. A 60-day feeding trial was conducted to evaluate the effects of N. oculata and Thalassiosira sp. monocultures on the growth performance (survival rate, yield, food coefficient, and specific growth rate) of shrimp and the physicochemical factors (DO, pH, NO2−-N, NO3−-N, NH4+-N, PO43−-P, COD and EI) and biotic factors (content of Vibrio Spp., Vibrio parahaemolyticus and bacteria) of the rearing water. The results showed that different microalgae had significant effects on the growth performance of shrimp and the environmental factors of rearing water. On the one hand, among the groups, the Thalassiosira sp. group (TG) had the highest survival rate, SGR and yield. On the other hand, similar to the nitrogen and phosphorus contents, the eutrophication index was significantly lower in the N. oculata group (NG) and TG than in control group (CG). Furthermore, of the groups, TG had the lowest Vibrio parahaemolyticus content. In summary, the Thalassiosira sp. monoculture in the rearing water absorbed nitrogen and phosphorus, reduced eutrophication, regulated the water environment, inhibited the growth of V. parahaemolyticus and increased the survival and yield of shrimp. This research provides an important theoretical basis and a representative demonstration for constructing a more efficient monoculture technology for microalgae and a new model for ecologically friendly and healthy shrimp cultivation and management.

Effects of carbon‐to‐nitrogen ratio (C:N) on water quality and growth performance of Litopenaeus vannamei (Boone, 1931) in the biofloc system with a salinity of 5‰

This study aimed to investigate the effects of carbon-to-nitrogen ratio (C:N) on water quality and shrimp growth performance during the grow-out culture of Litopenaeus vannamei in a biofloc system under a low salinity condition. Three biofloc treatments with a C:N (contained in feed and exogenous carbon source with the assumption that 75% of the feed nitrogen is excreted) of 8:1 (CN8), 16:1 (CN16) and 24:1 (CN24), respectively, were designed to stocking shrimp juveniles (~0.8 g shrimp−1) at a density of 270 individuals m−3, for a 63-day culture experiment at a salinity of about 5‰. Water parameters were monitored, and zootechnical indices were determined in the three treatments. Results showed that in CN8 treatment, pH, carbonate alkalinity, biofloc volume and TSS were significantly lower (p < 0.05), whereas TAN, nitrite and nitrate were significantly higher, than those in the other two treatments (p < 0.05). The zootechnical parameters of shrimp were not significantly different among the three treatments (p > 0.05), except that the survival rates in CN16 treatment (96.8 ± 2.0%) and CN24 treatment (93.7 ± 4.2%) were significantly higher than that of CN8 treatment (81.5 ± 6.4%, p < 0.05). Regression analysis revealed that the optimal C:N range for pH, SVI (sludge volume index), TAN, nitrate and survival rate was 20.5:1, 18.5:1, 21.0:1, 20.8:1 and 18.6:1. The results suggested that the C:N higher than 16 were suitable for culturing L. vannamei in the biofloc system with a salinity of 5‰, with an optimal range of 18.5–21.0:1.

Effects of dietary zinc sources and levels on growth performance, serum biochemical and immunological indexes and tissue zinc content of Litopenaeus vannamei

This investigation aimed at estimating the effects of two zinc (Zn) sources and dietary Zn levels on growth performance, serum biochemical and immune indexes and zinc content of tissues. There were two Zn sources, Zn sulphate heptahydrate (Zn-S) and Zn methionine (Zn-M) with five addition gradients (10, 20, 40, 60, 80 mg/kg), separately, added to the isonitrogenous and isolipidic basal diets. The group without additional Zn supplement served as the control group. In the eight-week experiment, Litopenaeus vannamei (0.34 g initial body weight) was fed 11 kinds of experimental diets respectively (shared control group) for 8 weeks. The results indicated that: 1) dietary Zn-S and Zn-M significantly improved weight gain rate (WGR), specific growth rate (SGR), protein efficiency rate (PER) of shrimp (P < 0.05). Feed conversion ratio (FCR) of both the Zn-S and Zn-M groups was distinctly reduced (P < 0.05). Zn sources and Zn levels and the interaction of them (IZSL) didn't distinctly influence survival rate (SR) of shrimp (P > 0.05). WGR, SGR, PER and FCR were not influenced by Zn sources and IZSL (P > 0.05) while they were significantly influenced by Zn levels (P < 0.05). 2) Contents of body crude protein (CP), crude lipid (CL) and crude ash (CA) were remarkably affected by dietary Zn levels (P < 0.05), and CP content of the body was significantly affected by Zn sources. IZSL had an impact on CA content (P < 0.05). 3) Contents of triglyceride (TG) and cholesterol (CHOL) in serum were significantly increased by dietary Zn-S and Zn-M (P < 0.05), and simultaneously, activities of acid phosphatase (ACP), alkaline phosphatase (AKP) and total superoxide dismutase (SOD) in serum were improved by dietary Zn-S and Zn-M (P < 0.05). There were distinct effects of IZSL on serous activities of ACP and AKP (P < 0.05). 4) Content of Zn in the body and muscle were significantly increased by dietary Zn-S and Zn-M (P < 0.05). Zn content of muscle was significantly affected by Zn sources, but Zn content of body and muscle were not influenced by IZSL (P > 0.05). In conclusion, dietary Zn-M and Zn-S both improved growth performance and immunity of shrimp. Based on WGR and Zn content of the whole body, the optimum requirements of Zn in Zn-S or Zn-M for shrimp were 93.36 ~ 112.28 mg/kg and 66.03 ~ 103.61 mg/kg. Additionally, Zn-M exhibited higher avail and immunity and was recommended in diets of Litopenaeus vannamei.

Dietary SYNSEA probiotic improves the growth of white shrimp, Litopenaeus vannamei and reduces the risk of Vibrio infection via improving immunity and intestinal microbiota of shrimp

The growth performance, immunological status, and intestinal microbiology of white shrimp, Litopenaeus vannamei, were evaluated after dietary administration of the commercial probiotic SYNSEA. Shrimp were fed a control diet (without probiotic supplement) and two levels of SYNSEA probiotic, a low concentration of SYNSEA (LSL) containing 105 CFU (g diet)−1Bacillus subtilis and 105 CFU (g diet)−1 lactic acid bacteria (LAB), and a high concentration of SYNSEA (LSH) containing 106 CFU (g diet)−1B. subtilis and 106 CFU (g diet)−1 LAB, for 12 weeks. Shrimp fed with the LSL diet significantly increased growth performance as well as final weight and feed efficiency compared to the control, but not the LSH diet. After being orally challenged with Vibrio parahaemolyticus, shrimp fed with LSL diet prior to the challenge or fed with LSL and pathogen simultaneously showed significantly lower mortality compared to the control. SYNSEA probiotic significantly improved shrimp immune response, including lysozyme activity in LSL and LSH groups, and phagocytic activity in the LSL group in comparison to the control. In addition, the gene expressions of anti-lipopolysaccharide factor 2 in LSL and LSH groups, and penaeidin 4 in LSL were also up-regulated. Although there was no significant difference among groups for hepatopancreas and intestinal morphology, the muscular layer thickness and villi height were slightly improved in the intestines of shrimp fed SYNSEA. The 16S rDNA gene amplicon sequence analysis using next-generation sequencing revealed a significant decrease in α-diversity (Margalef's species richness) after oral administration of SYNSEA due to an increase in the relative abundance of beneficial bacteria in the gut flora of shrimp, such as Lactobacillus, Shewanella, and Bradymonadales and a decrease in harmful bacteria, such as Vibrio, Candidatus_Berkiella, and Acinetobacter baumannii. Together the data suggest that the provision of SYNSEA probiotic at 105 CFU (g diet)−1B. subtilis and 105 CFU (g diet)−1 LAB can improve shrimp growth, enhance immunity, and disease resistance status of the host. In addition, these findings conclude that SYNSEA probiotic has great preventive and therapeutic potential for Vibrio infection in shrimp aquaculture.

Sodium metasilicate supplementation in culture water on growth performance, water quality and economics of indoor commercial-scale biofloc-based Litopenaeus vannamei culture

In super-intensive shrimp culture, water supplements are often used to adjust and stabilize water quality parameters, microbiological and environmental conditions, as well as suppress undesirable microorganisms. In addition, some water supplements are frequently utilized to boost the diatom population in water. These microorganisms are well known to enhance the shrimp growth performance, and present inhibitory effect against pathogenic vibrio. The present study evaluated the effect of sodium metasilicate (SM) supplementation in the culture water on the diatom population, water quality, zootechnical performance and economics of indoor commercial-scale biofloc-based culture. Litopenaeus vannamei (PL10, 4.1 ± 1.5 mg initial weight) were stocked in eight 500 m−2 commercial ponds with (BFT-SM) and without SM supplementation (BFT as a control), with four replicates per treatment. After 92 days (single phase, direct stock), the average values of silica (SiO2) were 8.2 mg L−1 in BFT-SM and 2.5 mg L−1 in BFT (control) (P < 0.05). Microscopical analysis indicated higher diatom dominance in BFT-SM, corroborated by higher chlorophyll-A concentrations. The shrimp biomass and yield were significantly higher in BFT-SM with 3.0 kg m−3 and 36.2 ton ha cycle−1 compared to BFT with 2.8 kg m−3 and 33.5 ton ha cycle−1, respectively. The BFT-SM treatment produced a 9.75% higher net profit margin than the BFT treatment and a 10.55% increase in revenue. Our study demonstrated positive impacts of SM supplementation on diatom population, resulting in enhanced shrimp performance and economic returns in indoor commercial-scale biofloc-based L. vannamei culture.

Growth and production of pacific white shrimp Litopenaeus vannamei (Boone, 1931) with different stocking densities in semi-intensive brackishwater liner ponds, Chennai, India: Technical report

Pacific white shrimp (Penaeus vannamei) is one of the main fishery products in fisheries sector. It has suitable for farming, stable production, easy to stocking high density, and highly diseases resistance. Most of the farmers in India choose to cultivate vannamei shrimp. Moreover, there are still other advantages of vannamei shrimp, its euryhaline species. No proper research yet been recorded on the effect of stocking density in survival rate and growth performance of L. vannamei. The aim of this report was to evaluate the growth, survival, and production performance of white shrimp (P. vannamei) in brackishwater liner ponds at different stocking densities.

Effects of dietary supplementation of Bacti-nil®Aqua on growth performance, feed utilization, immune responses, and body composition of the Pacific white shrimp, Litopenaeus vannamei

Effects of dietary supplementation of Bacti-nil®Aqua on growth performance, feed utilization, immune responses, and body composition of the Pacific white shrimp, Litopenaeus vannamei

Growth Performance, Immune-Related and Antioxidant Genes Expression, and Gut Bacterial Abundance of Pacific White Leg Shrimp, Litopenaeus vannamei, Dietary Supplemented With Natural Astaxanthin.

The current study examines the effect of dietary supplementation of ethanolic extract of Arthrospira platensis NIOF17/003, which is mainly natural astaxanthins (97.50%), on the growth performance, feed utilization, bacterial abundance, and immune-related and antioxidant gene expressions of the Pacific white leg shrimp, Litopenaeus vannamei. A total of 360 healthy L. vannamei postlarvae (0.19 ± 0.003 g) were divided into four groups (0, 2, 4, and 6 g natural astaxanthins/kg diet) each in three replicates, at an initial density of 30 PLs per tank (40 L capacity). The shrimp were fed the tested diets three times a day at a rate of 10% of their total body weight for 90 days. Diets supplemented with different astaxanthin levels significantly improved shrimp growth performance and feed conversion ratio compared to the control diet. No significant differences were observed in survival rates among all experimental groups. The immune-related genes (prophenoloxidase, lysozyme, beta-glucan binding protein, transglutaminase, and crustin) mRNA levels were significantly upregulated in groups fed with different concentrations of the natural astaxanthins in a dose-dependent manner. The prophenoloxidase gene is the highest immune-upregulated gene (14.71-fold change) in response to astaxanthin supplementation. The superoxide dismutase mRNA level was significantly increased with increasing dietary astaxanthin supplementation. In addition, increasing astaxanthin supplementation levels significantly reduced the count of heterotrophic bacteria and Vibrio spp. in the culture water and shrimp intestine. Overall, the current results concluded that diet supplementation with natural astaxanthin, extracted from Arthrospira platensis, enhanced the growth performance, immune response, and antioxidant status of L. vannamei.

Effect of dietary supplementation with sodium butyrate and tributyrin on the growth performance and intestinal microbiota of Pacific white shrimp (Litopenaeus vannamei)

Effect of dietary supplementation with sodium butyrate and tributyrin on the growth performance and intestinal microbiota of Pacific white shrimp (Litopenaeus vannamei)

Effects of fish meal replacement by three protein sources on physical pellet quality and growth performance of Pacific white shrimp (Litopenaeus vannamei)

The study investigated the effects of replacing fish meal with cottonseed protein concentrate (CPC), Tenebrio molitor (TM) and Clostridium autoethanogenum protein (CAP) on physical pellet quality and growth, feed utilization of Pacific white shrimp (Litopenaeus vannamei). A control diet (FM) was designed to contain 200 g/kg fish meal, then, 60 g/kg CPC, TM and CAP were used to replace the same amount of fish meal, respectively, to form four diets by pelleting. After the evaluation of physical quality, the four diets were fed to shrimp with initial body weight of 7.72 ± 0.01 g for 6 weeks. The results indicated that pellet hardness and bulk density were significantly increased (P < 0.05), when fish meal was substituted by CPC, TM and CAP, but no significant differences in starch gelatinization degree and pellet durability index were detected among the four diets (P > 0.05). In addition, the dissolution loss and powder content in CPC and CAP diets were significantly decreased (P < 0.05). Compared to FM group, TM group presented significantly higher feed conversion ratio (FCR) and lower protein retention(P < 0.05), but the other two groups showed no significant differences in growth performance (P > 0.05). Hepatopancreas amylase activity in CPC and CAP groups was significantly higher than that in FM group (P < 0.05), while no significant differences in the activities of hepatopancreas protease and pyruvate kinase, aspartate aminotransferase and alanine aminotransferase were found among the four groups (P > 0.05). The hepatopancreas and intestinal histology were normal in all groups without obvious injury. In conclusion, in the pelleted feed containing 200 g/kg fish meal, the replacement of 60 g/kg fish meal with CPC and CAP improved the physical pellet quality and had no negative effects on growth performance and nutrient utilization, but the replacement of 60 g/kg fish meal with TM decreased the growth performance and nutrient utilization of Pacific white shrimp.

The use of corn distiller’s dried grains with solubles as a protein source in practical diets for Pacific white leg shrimp Litopenaeus vannamei

A two-stage growth trial using identical diets was conducted to examine the viability of partially replacing soybean meal (SBM) with corn distiller’s dried grain with solubles (DDGS) simulating the commercial growth cycle of shrimp from 1 g to 19 g body weight. In both trials, the reference diet was formulated using 25 % SBM, 8 % fish meal (FM) and 20 % poultry by-product meal (PBPM). Test diets were formulated by replacing SBM with 5 %, 10 % and 15 % of DDGS, respectively. All diets contain approximately 36 % crude protein and 7 % crude lipid. In trial 1, fifteen shrimp with average initial weight of 1.04 ± 0.04 g were stocked into 98 l aquaria tank (equivalent to 150 shrimp m-2) in a completely randomized design with ten replicates per treatment and fed with the experimental diets for 52 days. In trial 2, shrimp (5.2 ± 0.2 g) were stocked randomly into 200 L clear tanks at a density of 50 shrimp per tank (equivalent to 250 shrimp m-2) with eight replicates per treatment and fed for 84 days. The results showed growth performance of shrimp in both studies was not affected as the dietary SBM was partially replaced with DDGS. There were no significant differences observed in terms of crude protein, fat content, dry matter and ash content of the shrimp in both studies. The results from this study demonstrated that corn DDGS could be used up to 15 % in commercial feed formulations without causing any adverse effect on growth, feed conversion, nutrient utilization efficiency and whole body composition. Since the price per unit protein of corn DDGS is much cheaper than SBM, the use of corn DDGS could offer the development of sustainable and economically sound practical diets for Pacific white leg shrimp L. vannamei.

Effects of dietary Lactobacillus reuteri and Pediococcus acidilactici on the cultured water qualities, the growth and non-specific immune responses of Penaeus vannamei

This study discussed the effects of two types of lactic acid bacteria, Lactobacillus reuteri (L. reuteri) and Pediococcus acidilactici (P. acidilactici), on the growth and nonspecific immunity of Penaeus vannamei (P. vannamei) and developed probiotic applications for shrimp cultivation.This study incorporated two types of lactic acid bacteria in shrimp feed through spraying. The shrimps were grouped according to the type and concentration of effective bacteria incorporated into their feed. This research was separated into 3 individual feeding treatment as control, L. reuteri (Lr groups) and P. acidilactici (Pa groups). The shrimp was feeding with 103, 105, and 107 cfu/feed (g) L. reuteri namely as Lr3, Lr5, and Lr7. The shrimp was feeding with 103, 105, and 107 cfu/feed (g) P. acidilactici were named Pa3, Pa5, and Pa7, respectively. Through 8 weeks of feeding, the results revealed that the use of shrimp feed incorporated with lactic acid bacteria did not cause negative effects on water quality. The testing items include ammonia-nitrogen concentration, nitrite-nitrogen concentration, and total vibrio count in the water. In addition, the lactic acid bacteria concentration in the water were in the range of 1.33 ± 0.58 × 101 to 9.77 ± 1.34 × 102 cfu/mL. Observations of the growth performance of the white shrimps after 8 weeks of feeding revealed that both bacteria were beneficial to shrimp growth. In particular, group Lr7 had the highest percentage weight gain (107.99 ± 3.92%), special growth rate (1.93 ± 0.07%), feed conversion ratio (3.34 ± 0.05), and survival rate (97.22 ± 4.81%).Furthermore, observations of the nonspecific immunity reactions of the white shrimps after 4 weeks of feeding indicated that on day 4, the total number of haemocyte in shrimps in groups Lr5, Lr7, Pa3, and Pa5 significantly increased. On days 1 and 4, the phenoloxidase activity and superoxide axion production rates of the Lr group and Ls group increased. This phenomenon was the most significant in group Lr7, and the effect continued until day 28. After day 7, the phagocytic rate of groups Lr5 and Lr7 significantly increased. In addition, Lr and Pa groups exhibited significant increases in the phagocytic index after days 4 and 14, respectively. This phenomenon was also the most significant in group Lr7.

Effects of dietary supplementation with tropical microfungi Mucor circinelloides and Trichoderma harzianum powder on growth performance, bacterial communities, and the biomass nutritional profile of white shrimp grow-out culture (Litopenaeus vannamei)

Microfungi have been explored further as supplement constituents in shrimp culture due to their rich protein, lipid, essential amino acids, fatty acids, and various bioactive compounds. The researchers have evaluated the effects of two microfungi powders (Mucor circinelloides and Trichoderma harzianum) as feed supplements on growth performance, bacterial communities, and the biomass nutritional profile of white shrimp (Litopenaeus vannamei). The results showed that commercial/artificial feed (Feng-Li) with supplementation microfungi powder had a different effect on white shrimp growth performance than control after 62 days of the grow-out period. Supplementation with 1.5% M. circinelloides powder (M-2) could improve the growth performance of white shrimp, especially the survival rate (81.33%), final body weight (5.21 g), and shrimp biomass (211.35 g). In contrast, supplementation with 1.5% T. harzianum powder (T-2) did not improve the growth performance of white shrimp compared to control (p > 0.05). Furthermore, it also affected the profile of the bacterial community in culture water as well as in shrimp intestines. Supplementation with both microfungi could reduce the total number of bacteria in culture water at the end of the experiment, where the lowest number was obtained in treatment T-2 (3.9 × 10 5 CFU/mL), followed by M-2 (9.9 × 10 5 CFU/mL) and control (4.4 × 10 6 CFU/mL). In the culture water, 20 isolates of culturable bacteria were found during the trial, with the dominant bacteria in M-2: Bacillus cereus, Bacillus velezensis, Gordonia polyisoprenivorans, T-2: Acinetobacter sp., Gordonia polyisoprenivorans, Micrococcus luteus. Based on average well colour development (AWCD), the highest bacterial activity was in the M-2 (0.297–0.707), followed by T-2 (0.226–0.717) and control (0.094–0.694). The highest substrate group utilised in M-2 and T-2 were polymers (0.896 and 1.348) and control: amines (0.100). The highest Shannon diversity index was obtained in the M-2 (2.508), followed by control (2.286) and the T-2 (2.157). As many as 11 isolates of culturable bacteria were found in the shrimp intestine, with dominant bacteria in M-2: Bacillus velezensis, Micrococcus luteus, Bacillus cereus, T-2: Bacillus velezensis, Micrococcus sp.2, Demequina activiva. The highest bacterial activity was in M-2 (2.259), followed by control (2.020) and T-2 (0.050). The highest substrate group utilisation was in M-2: polymers (2.564), T-2: carbohydrates (0.094), and control: polymers (2.185). The highest Shannon diversity index was in the M-2 (3.234), followed by control (3.230) and the T-2 (0.751). In addition, 1.5% M. circinelloides and T. harzianum supplementation increased white shrimp muscle protein content up to 79.21% and 80.40%, respectively, compared to control (76.73%). In conclusion, using Mucor circinelloides powder as a feed supplement can improve the growth performance of white shrimp, increase the functional/probiotic bacteria: B. cereus and B. velezensis in cultur and shrimp's intestine, and increase the protein content in shrimp muscle tissue. However, more in-depth research is needed, especially on anti-nutritional compounds from fungi that affect shrimp growth.

Role of myo-inositol supplementation against toxicity of excessive dietary copper in Pacific white shrimp Litopenaeus vannamei

Raw materials for making dried shrimp (a type of foodstuff) are mostly from farmed shrimp and preliminary findings indicated that head copper (Cu) concentrations in some commercial dried shrimp products exceeded the safe limit specified in pollution-free aquatic products (50 mg/kg), which may influence food safety. Therefore, a 63-day feeding trial was conducted to explore effects of dietary Cu concentrations on accumulation of Cu in tissues, growth performance, immune response and antioxidant status of Pacific white shrimp (Litopenaeus vannamei). Moderating effect of myo-inositol (MI, adding 200 mg/kg diet) on the adverse impacts caused by excessive dietary Cu was also investigated. 600 shrimp (initial weight: 0.89 ± 0.00 g) were divided into five groups: 37.08 mg Cu/kg diet group (control group), 62.57 mg Cu/kg diet group, 125.99 mg Cu/kg diet group, 63.41 mg Cu/kg diet group (supplemented with MI) and 119.19 mg Cu/kg diet group (supplemented with MI). The results showed that dietary Cu concentrations increased from 37.08 to over 62.57 mg/kg, hepatopancreas Cu concentrations raised from 29.04 to 233.43–263.65 mg/kg, and muscle Cu concentrations only increased from 6.22 to 6.99–8.39 mg/kg. Report to control group, excessive Cu concentration (125.99 mg/kg) didn’t significantly affect growth performance, but it notably reduced whole body lipid content and immune response, induced oxidative stress and damaged the hepatopancreas structure, which was ameliorated by MI supplementation. The results suggested that consuming shrimp head and its processed products weren’t recommended. Cu concentrations of commercial feeds for Pacific white shrimp should be controlled below 62.57 mg/kg. Additionally, MI supplementation mitigated the negative impacts induced by excessive dietary Cu.

Effects of tributyrin on the growth performance, immune response and intestinal microbiota of shrimp (Litopenaeus vannamei)

The present study aimed to evaluate the effects of tributyrin (TB)on the growth performance, intestinal immune and microbiota of shrimp (Litopenaeus vannamei). A total of 720 healthy shrimp (0.88 ± 0.02 g) were fed with four different diets supplemented with 0, 500, 1000, and 1500 mg/kg of TB for 42 days. The current results showed that 1500 mg/kg TB dietary have positive impacts on growth performance and digestive enzymes activity, increasing the content of whole-body crude protein and lipid. In addition, TB supplement improved the intestine healthy with two possible mechanisms. 1) TB inhibited biomolecule damages including lipid peroxidation and protein carbonyl by improves antioxidant capacity 2) TB inhibited the expression level of TNF-α and IL-16 genes to attenuate inflammatory response by regulating the NF-kB activation of intestine. As for the intestinal microbiota, the microbial diversity and richness decreased and the abundance of potential probiotic (Rhodobacteraceae, Pseudomonas) increased in TB groups. The present results suggested that TB could be used as nutritional supplement to improve intestinal health of shrimp.

Growth performance of shrimp and water quality in a freshwater biofloc system with a salinity of 5.0‰: Effects on inputs, costs and wastes discharge during grow-out culture of Litopenaeus vannamei

This study aimed to evaluate the effects of biofloc technology on inputs, costs and wastes discharge during grow-out culture of Litopenaeus vannamei under a low salinity condition. Two systems (water volume 5 m3, salinity 5‰) were designed: biofloc system (BFT) with addition of molasses (C:N 20:1), and clear water system (CW), for a 63-day culture experiment with shrimp juveniles (~0.80 g, 90 shrimp m−3). Water quality and zootechnical performance were monitored, and the costs and benefits were estimated. Results showed that the levels of pH (7.75 ± 0.01), carbonate alkalinity (86.6 ± 1.9 mg CaCO3 L−1), biofloc volume (29.1 ± 2.1 mL L−1), total suspended solids (588.7 ± 40.0 mg L−1) and total ammonia nitrogen (1.42 ± 0.12 mg L−1) in BFT treatment were significantly higher than those in CW (7.26 ± 0.07, 61.9 ± 1.2 mg CaCO3 L−1, 1.1 ± 0.7 mL L−1, 75.4 ± 9.4 mg L−1 and 0.62 ± 0.06 mg L−1, P < 0.05). Significantly higher survival rate (100%) and productivity (1.10 ± 0.02 kg m−3) were observed in BFT treatment, when compared to those in CW (92.6 ± 3.7% and 0.96 ± 0.01 kg m−3, P < 0.05). The total cost in BFT treatment were 9.51 ± 0.55 USD kg−1, significantly lower than that in CW (42.20 ± 0.67 USD kg−1, P < 0.001). The discharge of waste water, salt, ammonia, nitrite and nitrate in BFT treatment decreased 78.9–99.7% compared to that in CW. The results indicated that biofloc technology could be adopted for an environment-friendly and cost-effective culture of L. vannamei with a salinity as low as 5.0‰.

Combined application of glycerol monolaurate and tributyrin improves the growth performance, antioxidant capacity, nonspecific immunity, gene expression and intestinal health of juvenile Litopenaeus vannamei

This study aimed to investigate the effects of the glycerol monolaurate (GML) and tributyrin (TB) and their interaction on the growth performance, body composition, nonspecific immunity, gene expression and intestinal microbiota of Litopenaeus vannamei (initial weight 0.24 ± 0.00 g). The feeding trial comprised a completely randomized 3 × 2 factorial design and six formulated diets with two different GML levels (0.10% and 0.15%) and three different TB levels (0.10%, 0.15%, and 0.20%) named G10T10, G10T15, G10T20, G15T10, G15T15, and G15T20, respectively. Results showed that three groups (G10T15, G15T10, and G15T15) had significantly higher final mean weight, weight gain rate, specific growth rate (P < 0.05) and lower feed conversion ratio than the other groups (P < 0.05). Catalase at low and medium addition levels of TB (G10T10, G10T15, G15T10, and G15T15) was promoted by GML (P < 0.05), and malondialdehyde was inhibited by GML (P < 0.05). Glutathione in G10T15 and G15T10 had the highest values among the groups (P < 0.05). Acid phosphatase was greatly influenced by GML, TB, and their interaction, and its maximum value was found in G15T10 (P < 0.05). Alkaline phosphatase was influenced by TB and was significantly higher in G10T15 and G15T15 than in the other groups (P < 0.05). The mRNA expression of lysozyme (LZM), heat shock protein 70 (HSP70), and phenol oxidase (PO) were significantly affected by GML, TB, and their interaction (P < 0.05). At the phylum level, Firmicutes and Firmicutes/Bacteroidetes ratio increased and then decreased at low level of GML (0.10%) and gradually decreased at high level of GML (0.15%), with minimum values in the G10T15 and G15T10 groups (P < 0.05). In conclusion, 0.15% GML and 0.10% TB were the optimal dietary addition on the basis of growth performance, nonspecific immunity, and intestinal health of the juvenile shrimp (Litopenaeus vannamei).

Dietary fish oil levels modulated lipid metabolism, immune response, intestinal health and salinity stress resistance of juvenile Penaeus monodon fed a low fish-meal diet

Dietary fish meal (FM) and fish oil (FO) replacement are crucial for the sustainable development of aquaculture. An eight weeks feeding trial was conducted to evaluate the potential replacing FM with soy protein concentrate, and the suitable FO level for a low FM diet of Penaeus monodon. A diet containing 25% FM was used as the control (C diet), and three other diets were formulated to contain 15% FM, and supplemented with 3%, 2%, 1% FO [high FO (HF), medium FO (MF) and low FO (LF), respectively]. The experiment was conducted in quadruplicates (30 shrimp per replicate, average weight 1.00 ± 0.01 g). The results indicated that besides the final body weight, there were no differences in weight gain, feed efficiency and survival rate observed among the four groups. The results of the acute salinity stress showed that shrimp fed the C and MF diets showed a similar survival rate, which was significantly higher than those fed a LF diet. Shrimp that were fed HF, MF and LF diets showed a lower level of fatty acid transport-related mRNA expression in the hepatopancreas, compared with those fed the C diet. Shrimp fed HF, MF and LF diets showed lower expression levels of superoxide dismutase, endoplasmic reticulum protein 57 and immune deficiency (IMD) in the hepatopancreas than those fed the C diet. Shrimp that were fed a LF diet showed the lowest expression levels of inhibitor of apoptosis proteins, Toll and tumor necrosis factor receptor associated factor 6 (TRAF6) in the hepatopancreas, as well as the highest expression levels of Toll, extracellular signal-regulated kinase, Relish and TRAF6 in the intestine among four groups. Intestinal microstructure damage was observed in shrimp that were fed a LF diet, and intestinal endoplasmic reticulum (ER) swelling was observed in shrimp fed MF and LF diets. In conclusion, these results indicated that the growth performance of shrimp was not affected when the FM and FO contents decreased, whereas a low content of FM negatively influenced the immune response in shrimp by modulating IMD and ER stress related gene expression. Under low FM conditions, a suitable dietary FO level would benefit to the lipid transport, hepatopancreas and intestine health, as well as the immune response of shrimp.

Improvement in the probiotic efficacy of Bacillus subtilis E20-stimulates growth and health status of white shrimp, Litopenaeus vannamei via encapsulation in alginate and coated with chitosan

The aim of this study was to increase the efficacy of probiotic Bacillus subtilis E20 by encapsulating the probiotic in alginate and coating it with chitosan. The protective effect was evaluated by firstly ensuring the viability of encapsulated probiotics in simulated gastrointestinal fluid (SGF) and simulated intestinal fluid (SIF) conditions and then at different storage temperatures. In addition, the encapsulated probiotic was incorporated into the diet to improve the growth performance and health status of white shrimp, Litopenaeus vannamei. B. subtilis E20 has the ability to survive in SGF when encapsulated in 1.5–2% alginate and coated with 0.4% chitosan. Furthermore, viability increased significantly in SIF compared to the probiotic encapsulated in 1% alginate and coated with 0.4% chitosan and the non-encapsulated probiotic. Longer storage time and adverse conditions affected probiotics' survival, which was improved by the encapsulation with significantly higher viability than the non-encapsulated probiotic at different temperatures and storage duration. Encapsulation of B. subtilis E20 and dietary administration at 107 CFU kg−1 decreased shrimp mortality after a Vibrio infection, thereby improving shrimp's disease resistance, while the non-encapsulated probiotic required 109 CFU kg−1 to achieve better resistance. Although the best results of growth performance, immune response, and disease resistance against Vibrio alginolyticus were found in the shrimp fed with the diets supplemented with encapsulated probiotic at >108 CFU kg−1, shrimp's growth performance and health status improved after being fed 107 CFU kg−1 encapsulated probiotic for 56 days. Together, the results of this study prove that encapsulation could improve the viability of probiotic in different gastrointestinal conditions and adverse storage temperatures. Overall, lower concentrations of encapsulated probiotic B. subtilis E20 (107 CFU kg−1) was able to increase the growth performance and health status of shrimp.