Dietary supplementation of microbial floc heightens growth and improves digestive,immune, antioxidant enzymes activity and ammonia resistance in Opsariichthys kaopingensis

The present study was conducted to evaluate the effects of dietary supplementation of microbial floc on growth, digestive and immune enzymes activity, antioxidant status and ammonia resistance in Opsariichthys kaopingensis. Four hundred fifty healthy O. kaopingensis juveniles (6.21 ± 0.32 g) were randomly assigned to 15 tanks. Juvenile fish were fed five experimental diets containing microbial floc 0 (B0 control), 4% (B4), 8% (B8), 12% (B12) and 16% (B16), respectively, for 30 days. Results showed that B12 could significantly enhance weight gain rate (WGR), specific growth rate (SGR) and protein efficiency ratio (PER), reduce feed conversion rate (FCR) (p < .05), compared to the control. The activity of protease, lipase and amylase in hepatopancreas and gut of B12 group were higher than that of the control (p < .05). Also, significant increases in lysozyme (LSZ), glutamic pyruvic transaminase (GPT) and alkaline phosphatase (AKP) activities of O. kaopingensis were found at B12 group (p < .05). Comparing the antioxidant capacity, the activities of superoxide dismutase (SOD), total antioxidant capacity (T‐AOC), catalase (CAT) and ascorbic acid (ASA) of juveniles in B12 group were significant highly (p < .05) than control, and the content of malondialdehyde (MDA) was much lower than control in gill, kidney, hepatopancreas, intestine and serum under this experiment condition. After ammonia challenge, survival rate in all dietary supplementation of microbial floc treatment groups was significantly increased (p < .05). Overall, these findings suggest that dietary supplementation of microbial floc enhanced growth, digestion, antioxidant and immune response, and increased ammonia stress resistance in O. kaopingensis. The suitable supplemental level of approximately 12% microbial floc was recommended in the present study.     

Antioxidant effects of nanoencapsulated lipoic acid in tissues and on the immune condition in haemolymph of Pacific white shrimp Litopenaeus vannamei (Boone, 1931)

The antioxidant and oxidative damage responses and immune parameters in shrimp, Litopenaeus vannamei, reared in clear water (CW) and in a biofloc system (BFT) were evaluated. The animals were given feed supplemented with either nanocapsules containing the antioxidant lipoic acid (NCLA) or empty nanocapsules (NC). Antioxidant and oxidative stress analyses were evaluated by measuring glutathione S‐transferase activity (GST), reduced glutathione (GSH) concentration and lipid peroxidation (TBARS) in the gills, hepatopancreas and muscle. The immune parameters were then determined by the differential hemocyte count in the haemolymph. The final weight of the shrimp reared in both CW and BFT and treated with NCLA increased (p < .05). The shrimps reared in BFT showed increased GST activity in the gills and hepatopancreas after NCLA treatment (p < .05). Higher GSH levels were observed in the hepatopancreas with NCLA supplementation in CW and BFT (p < .05). Decreased levels of TBARS were observed in the gills and muscles of shrimp supplemented with NCLA and maintained in CW (p < .05). A decrease in the percentage of hyaline hemocytes and an increase in granular hemocytes were observed in shrimp treated with NCLA in CW and BFT (p < .05). The antioxidant treatment induced positive responses in terms of the zootechnical, biochemical and immunological parameters.     

Immune responses by dietary supplement with Astragalus polysaccharides in the Pacific white shrimp,Litopenaeus vannamei

Two experiments were conducted to investigate the immune‐enhancing effect of dietary supplement with Astragalus polysaccharides (APS) on the Pacific white shrimp, Litopenaeus vannamei. In experiment 1, the optimal APS dose was determined based on the immune responses of shrimps fed APS diet for 30 days. In experiment 2, the effect of APS supplementation on immune response of shrimp suffering white spot syndrome virus (WSSV) challenge was determined. Results showed that the total haemocyte count and phagocytic activity in shrimps fed APS diets significantly (p < .05) increased in comparison with those fed the basal diet. Dietary supplement with APS markedly (p < .05) increased the activity of phenoloxidase (PO), total superoxide dismutase (SOD), lysozyme (LZM), acid phosphatase and alkaline phosphatase in shrimp hemolymph, but decreased the maleic dialdehyde (MDA) content. Significantly higher (p < .05) activity on PO, SOD and LZM and lower (p < .05) MDA content have also been found in shrimps suffering WSSV challenge. Therefore, APS could be used as a safe and effective feed additive in shrimp aquaculture, and the optimal dose of APS for the Pacific white shrimp was suggested to be 0.2 g/kg based on our results.     

Earthworm,Eisenia fetida,bedding meal as potential cheap fishmeal replacement ingredient for semi‐intensive farming of Nile Tilapia,Oreochromis niloticus

The study amalgamated earthworm and agro‐industrial wastes through vermicomposting and then evaluated the potential of the bedding (mixture of Eisenia fetida and vermicompost) to replace fishmeal in semi‐intensive farming of Oreochromis niloticus. The bedding was used to substitute fishmeal at inclusion rates of 100, 60, 30 and 0% (D100, D60, D30 and control D0). In triplicates, the four homogeneous diets were fed to quadruplicate groups of 30 g O. niloticus for 112 days. There was no significant difference (p > .05) in mortalities, average length gain and FCR among all tests. Nevertheless, diet D0 had significantly (p < .05) superior amino acid profile, low fibre content and fish carcass crude protein (63.2 ± 0.72% dry matter). Subsequently, D30 and D0 produced fish with significantly higher (p < .05) mean weight gain (256.03 ± 0.4 g) and biomass (369,136 g) respectively. On to the contrary, diet D100 had significantly higher (p < .05) crude lipids content (9.4 ± 0.6% dry matter), economic returns and profit index than the control diet due to the comparatively low cost of producing the earthworm bedding. This simple biotechnology can commercially be upscaled to sustainably produce cheap and nutritious fish feed capable of increasing yields and maximizing profits.     

Effects of dietary herbal formulae combined by Astragalus polysaccharides,chlorogenic acid and allicin in different combinations and proportions on growth performance,non‐specific immunity,antioxidant status,vibriosis resistance and damage indexes of Litopenaeus vannamei

In this study, a feeding trial followed by a challenge test was performed to evaluate effects of six herbal formulae which were different combinations of Astragalus polysaccharides (APS), chlorogenic acid (CGA) and allicin on growth performance, non‐specific immune response, antioxidant capacity, disease resistance and biomolecule damage of white shrimp Litopenaeus vannamei. Shrimp were fed seven diets, control diet (basal diet with no herbal formulae) and six herbal formula diets (G1–G6, basal diet supplemented with 0.1% APS + 0.05% allicin, 0.1% APS + 0.1% allicin, 0.1% CGA + 0.05% allicin, 0.1% CGA + 0. 1% allicin, 0.1% APS + 0.1% CGA and 0.1% APS + 0.1% CGA + 0.05% allicin respectively), for 21 days. After that, shrimp were challenged with Vibrio harveyi and then the cumulative mortality of shrimp was recorded for 7 days post challenge. The results showed that there were no significant differences in growth performance among all groups, while the non‐specific immune responses and antioxidant indexes were significantly improved (p < .05) in shrimp fed herbal formula diets when compared to the control. Meanwhile, the lowest cumulative mortality was observed in shrimp fed herbal formula diets with 0.1% APS, 0.1% CGA and 0.05% allicin supplementation after V. harveyi challenge. Additionally, herbal formulae could not cause biomolecule damage to the hepatopancreas of shrimp. In conclusion, these results indicated that synergistic effect of APS, CGA and allicin helped to boost immunity, antioxidant capacity and disease resistance of shrimp without biomolecule damage.     

Evaluation of some haemolymph biochemical properties and F‐cell prevalence in hepatopancreas of white leg shrimp (Litopenaeus vanammei) after fed diets containing apple cider vinegar and propionic acid

The present study aimed to evaluate the effect of dietary ACV (apple cider vinegar) and PA (propionic acid) supplementation on some biochemical properties of haemolymph and fibrillar cell (F‐cell) number in the hepatopancreas of shrimp. Five different diets supplemented with 0%, 1%, 2%, 4% ACV and 0.5% PA diets were fed to Litopenaeus vanammei. Some biochemical parameters of haemolymph (cortisol, alkaline phosphatase, albumin, urea, uric acid, creatinine, phosphorus, total hemocyte count) and prevalence of F‐cell in hepatopancreas were examined after 60 days feeding trial. The albumin concentration and total hemocyte count in 2% and 4% ACV and PA groups were significantly higher than those of other groups (p < .05). Moreover, the highest phosphorus concentration was detected in shrimp fed 4% ACV and PA experimental diets (p < .05). No significant differences in haemolymph cortisol, urea, uric acid, creatinine, alkaline phosphatase and tubule area were observed among the experimental groups (p > .05). 2% ACV group showed more F‐cell number in hepatopancreas than other groups while the reduction in F‐cell number was observed in the PA group. Based on these observations, the tested ACV and PA diets remarkably exhibited positive impacts on nutritional value and they may be a potential for adding to shrimp diet.     

Hypoxia‐induced changes in survival,immune response and antioxidant status of the Pacific white shrimp (Litopenaeus vannamei) fed with graded levels of dietary myo‐inositol

A 3‐hr experiment was conducted to investigate the effects of dietary myo‐inositol (MI) supplementation on survival, immune response and antioxidant abilities in Litopenaeus vannamei under acute hypoxia stress. Six practical diets were formulated with supplementation of graded levels (control group 0, 0.1, 0.2, 0.4, 0.8 and 1.6 g/kg dry diet) of MI and were randomly assigned to triplicate groups of L. vannamei (mean weight 0.40 ± 0.00 g) for 8 weeks. Ten healthy shrimp (final mean weight approximately 11–14 g) randomly selected from each tank were exposed to hypoxia stress after feeding trial. After 3‐hr acute hypoxia stress, survival of shrimp fed MI‐supplemented diets (except 0.1 and 0.4 g/kg diets) was significantly increased compared with the control group. Shrimp fed control diet had lower activities of alkaline phosphatase (AKP), acid phosphatase (ACP), total antioxidant capacity (T‐AOC) and glutathione peroxidase (GPX), and higher malondialdehyde (MDA) and protein carbonyl (PC) contents in hepatopancreas than those fed the MI‐supplemented diets. In addition, mRNA expression levels of heat shock protein 70 (Hsp70), catalase (CAT) and penaeidin were significantly differentially regulated in hepatopancreas. In summary, dietary MI supplementation may have a positive effect on improving resistance to acute hypoxia stress of L. vannamei.     

Effects of Rosemary (Rosmarinus officinalis) extract on growth,blood biochemistry,immunity, antioxidant,digestive enzymes and liver histopathology of rainbow trout,Oncorhynchus mykiss

This research was designed to determine the effects of rosemary (Rosmarinus officinalis) extract on growth, blood biochemistry, immunity, antioxidant, digestive enzymes and liver histopathology of rainbow trout. In a 40‐day diet experiment, rainbow trout was fed with the experimental diets containing 0.4, 0.7, 1 and 3 g/kg of rosemary. 0.4 and 0.7 g/kg rosemary extracts had no significant effect on all parameters studied (p > .05). The growth performance (SGR and WG) and feed utilization (FCR and FER) of the fish increased with the increase in the rate of rosemary in the feed (p < .001). Additionally, only the final weight levels were significant at the linear level (p < .05). Rosemary's 1 and 3 g/kg doses increased total protein, trypsin, amylase, lipase, superoxide dismutase (SOD), catalase (CAT), lysozyme, total immunoglobulin (IG) and white blood cell (WBC) levels when compared to control group. However, glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol and triglyceride levels decreased significantly (p < .001). Moreover, these doses of rosemary caused a significant reduction in steatosis of liver hepatocytes compared to the control group. In conclusion, the present study showed that rosemary may be useful in reducing the stress effects by increasing the growth, antioxidant, digestive enzymes and immunity levels, as well as reducing the rate of steatosis in the liver of rainbow trout.     

Dietary quercetin improved the growth,antioxidation, and flesh quality of grass carp (Ctenopharyngodon idella)

To investigate the effects of dietary quercetin on growth, antioxidation, and flesh quality of grass carp, Ctenopharyngodon idella, six diets were prepared with quercetin inclusion rates of 0 (control diet), 0.1, 0.2, 0.4, 0.6, and 0.8 g/kg. Grass carp with a body weight of 13.3 ± 0.1 g were fed with one of the six diets for 60 days. The weight gain (WG) showed a quadratic relationship with dietary quercetin levels; the supplementation of 0.4 g/kg quercetin significantly improved WG (+4.73%) and decreased feed conversion ratio (?0.06) (p < .05) when compared to those of the control group. The intestinal fat ratio was reduced by the addition of 0.2 or 0.4 g/kg of quercetin (p < .05), and serum activities of alkaline phosphatase and superoxide dismutase were increased by the addition of 0.4 and 0.6 g/kg of quercetin (p < .05). The inclusion of 0.2–0.6 g/kg of quercetin increased the contents of delicious amino acids and decreased the cooking loss of flesh (p < .05). Flesh collagen content was increased by the addition of 0.4–0.8 g/kg of quercetin (p < .05). In conclusion, dietary quercetin could improve the growth and enhance the antioxidation and flesh quality of grass carp, with the recommended supplemental level of quercetin was 0.37 g/kg.     

Effects of exogenous multienzyme complex supplementation in diets on growth performance,digestive enzyme activity and non‐specific immunity of the Japanese seabass,Lateolabrax japonicus

This experiment aimed to investigate the effects of exogenous multienzyme complex (EC) on growth performance, digestive enzyme activity and non‐specific immunity of the Japanese seabass, Lateolabrax japonicus (initial weight 27.09 ± 0.08 g). EC includes protease, xylanase, glucanase and mannase. Japanese seabass were given six levels of EC (0, 0.5, 1.0, 1.5, 2.0 and 2.5 g/kg) for 28 days. Results show that EC significantly enhanced the weight gain rate and specific growth rate (p < .05), while the feed conversion ratio reduced significantly (p < .05). Activities of lipase and trypsin in liver and intestine significantly increased (p < .05). Alkaline phosphatase, superoxide dismutase and lysozyme activities in serum and liver significantly increased (p < .05), while the content of malondialdehyde in liver significantly declined (p < .05). Regression analysis showed that the optimal supplementation of EC in WGR, SGR, FCR, SOD and LZM activity in serum was 1.66, 1.67, 1.81, 1.71 and 1.53 g/kg, respectively, while the best SOD, LZM activity in liver, trypsin activity in liver and intestine supplement were 1.64, 1.51, 1.81 and 1.97 g/kg. In conclusion, EC supplemented can improve the growth performance, digestive enzyme activity and non‐specific immunity of Japanese seabass, and it is recommended that the optimal supplementation of EC in diets of Japanese seabass is 1.5–2.0 g/kg.     

Effects of dietary administration of Macsumsuk® on growth and stress to low salinity and low dissolved oxygen in whiteleg shrimp,Litopenaeus vannamei (Boone, 1931) juveniles

An 8‐week study was conducted to explore the results of Macsumsuk^® as a feed additive on the stress tolerance and growth of Litopenaeus vannamei in 15 culture tanks of 36 L each. Three hundred shrimp averaging 0.1 ± 0.01 g were fed with five isonitrogenous (48.38 ± 0.38% CP) diets (in triplicate groups) containing kaolinite (Macsumsuk^®) at 0%, 0.3%, 0.6%, 1.2% and 2.4%, namely Mk₀, Mk_0.3, Mk_0.6, Mk_1.2 and Mk_2.4. Specific growth rate (SGR) and weight gain (WG) of shrimp fed diets Mk_1.2 and Mk_2.4 were significantly better than those of shrimp fed diet Mk₀ (p < .05). However, SGR and WG of shrimp fed diets Mk_0.6, Mk_1.2 and Mk_2.4 were not significantly different. Protein efficiency ratio (PER) and feed efficiency (FE) of shrimp fed diets Mk_1.2 and Mk_2.4 were significantly better than those of shrimp fed diets Mk₀, Mk₀.₃ and Mk_0.6. Furthermore, the survival of shrimp fed diet Mk_2.4 was significantly lower than that of shrimp fed diet Mk_0.6 (p < .05). Cumulative mortality of shrimp fed diet Mk_1.2 was significantly lower than that of shrimp fed diet Mk₀ at 1–1.5 hr post‐stress to low dissolved oxygen (from 6.1 mg/L to 2.9 mg/L) and 4–5 hr post‐stress to low salinity (from 32‰ to 1‰) (p < .05). The optimum dietary Macsumsuk^® level for juvenile L. vannamei was determined as 1.97% by the polynomial regression analysis of weight gain.     

Suitable dietary chitosan improves the growth performance,survival and immune function of tiger shrimp,Penaeus monodon

Different levels of dietary chitosan on growth performance, survival and stress tolerance to air exposure was studied in tiger shrimp, Penaeus monodon. Shrimp (mean initial wet weight about 1.16 g) were fed with six different diets (C0, C0.05, C0.1, C0.2, C0.3 and C0.4) containing six level of chitosan (0%, 0.05%, 0.1%, 0.2%, 0.3% and 0.4% respectively) in triplicate for 60 days. Growth performance [final body wet weight (FBW); weight gain (WG); biomass gain (BG)] of shrimp fed chitosan‐containing diets were higher (P < 0.05) than that of shrimp fed the basal diet, shrimp fed C0.1 diet showed the highest value of growth performance. Survival of shrimp in C0.1 and C0.2 diet groups were higher (P < 0.05) than that of shrimp in C0, C0.05 and C0.4 diet groups but without statistical difference (P > 0.05) in shrimp fed C0.3 diet group. Whole body and muscle lipid contents decreased with increasing dietary chitosan levels. Plasma total cholesterol and triglyceride contents of shrimp fed C0 diet was significantly higher (P < 0.05) than that of shrimp fed chitosan‐containing diets. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities of shrimp fed C0 diet were higher than those of shrimp fed chitosan‐containing diets. Digestive gland malondialdehyde (MDA) and carbonyl protein contents of shrimp fed chitosan‐containing diets were lower (P < 0.05) than that of shrimp fed C0 diet. Total haemocyte count of shrimp fed C0 diet was lower (P < 0.05) than that of shrimp fed chitosan‐containing diets. On the contrary, the haemolymph clotting time of shrimp fed C0 diet was higher (P < 0.05) than that of shrimp fed chitosan‐containing diets. In conclusion, all results suggested that dietary intake containing 0.1% and 0.2% chitosan enhanced the growth of shrimp, whereas a higher level than 0.3% and 0.4% decreased growth of shrimp. Second‐degree polynomial regression analysis of WG and BG indicated that the optimum supplement of dietary chitosan level should be 0.19–0.21%.     

Growth performance,haematology and intestinal histo‐morphology of Nile tilapia fed on Indian Lotus (Nelumbo nucifera Gaertn.) leaf powder at different concentrations

Indian lotus, Nelumbo nucifera (Gaertn.) is a valued medicinal plant that exhibits several pharmacological properties. The present work aimed to investigate the effect of Indian lotus as a feed supplement on the growth performance, haematological and biochemical indices, and intestinal histo‐morphology of Nile tilapia (Oreochromis niloticus L.). The fish were randomly distributed into four groups and fed on a basal diet containing Indian lotus leaf powder at different concentrations (0, 0.1, 0.2 and 0.4%) for up to 60 days. The results elucidated that Indian lotus supplemented diets (0.2% and 0.4% followed by 0.1%) significantly improved weight gain, specific growth rate (%) and feed conversion ratio (p < .05). The feed intake was significantly increased in the fish fed on the Indian lotus supplemented diets in a dose‐dependent manner (p < .05). However, Indian lotus had no significant effect (p > .05) on survival rate, total erythrocytes (RBCs) count, haemoglobin (Hb) and hematocrit value (PCV, %) except a significant reduction on Hb content of the fish fed on 0.2% Indian lotus and a significant increase in PCV (%) in the fish fed on 0.1% Indian lotus (p < .05). The total leucocytes (WBCs), neutrophils and lymphocytes counts displayed significant elevations in the fish fed on the Indian lotus diets especially at 0.2% and 0.4%, whereas significant reduction in neutrophils count in the fish fed on 0.1% Indian lotus (p < .05) was observed. The serum glucose was significantly decreased in the fish fed on Indian lotus (0.1% and 0.2%), whereas cholesterol and triglycerides were markedly increased in the fish fed on the Indian lotus supplemented diets (p < .05). Moreover, the intestinal villous heights and the numbers of goblet cells and intraepithelial lymphocytes (IEL) were significantly boosted in all parts of the intestine in all Indian lotus diet groups as compared with the control group. However, as an exception, villous heights in the middle part of the intestine in the fish fed on 0.1% and 0.4% diets (p < .05) were not affected. In the proximal part, the villous heights and the numbers of goblet cells were markedly increased in fish fed on 0.2% and 0.4% diets followed by 0.1% diet. The fish fed on 0.2% lotus supplemented diet followed by 0.1% and 0.4% supplemented diets exhibited significant elevations in villous heights in the distal part and the numbers of goblet cells in the middle part of the intestine. There were no significant differences between the fish fed on the supplemented diets in the numbers of goblet cells in the distal part and the numbers of IEL in the proximal and middle parts (p > .05). In the distal part, the numbers of IEL revealed a significant elevation in 0.4% lotus supplemented diet followed by 0.1% and 0.2% lotus supplemented diet groups (p < .05). Therefore, this study indicates the advantageous effect of the Indian lotus leaves as a natural feed additive for improving growth, intestinal structure and hence, health status of Nile tilapia.     

Improvement of growth performance,water quality and disease resistance against Vibrio harveyi of postlarval whiteleg shrimp (Litopenaeus vannamei) by administration of mixed microencapsulated Bacillus probiotics

The objective of this study was to investigate the effects of mixed Bacillus on growth, water quality and disease resistance against Vibrio harveyi in whiteleg shrimp (Litopenaeus vannamei). Postlarval shrimp (PL₃₀) were fed with (a) a basal diet (the control), (b) a diet containing mixed freeze‐dried Bacillus probiotics (FB) and (c) addition of mixed microencapsulated Bacillus probiotics (MB) in culture water. Addition of FB and MB probiotics improved (p < .05) growth, feed efficiency, survival and culture water quality (ammonia and nitrite) compared to the control group although there was no difference (p > .05) between the two treated groups. Bacillus numbers in gastrointestinal tracts and culture water of FB‐ and MB‐administrated shrimp were higher (p < .05) than in the control. After a 30‐day culture, shrimp were infected with V. harveyi and monitored for 10 days. A significant reduction (p < .05) in cumulative mortality was observed in FB‐ and MB‐supplemented shrimp (43.24% and 45.05%, respectively), compared to the control (63.06%). This finding demonstrated that administration of microencapsulated probiotics was as effective as freeze‐dried probiotics for improving growth, feed efficiency, survival, Bacillus in gastrointestinal tracts, water quality (ammonia and nitrite) and conferring disease resistance to V. harveyi.     

The effects of two fish species mullet,Mugil cephalus,and tilapia,Oreochromis niloticus,in polyculture with white shrimp,Litopenaeus vannamei,on system performances: A comparative study

A comparative study was carried out to compare the effect of caging mullet and tilapia in a shrimp polyculture system. In six shrimp tanks (three tanks for each fish species), either mullet, Mugil cephalus (CCT‐SM), or tilapia, Oreochromis niloticus (CCT‐ST), was stocked in cages. In three other tanks, mullets were allowed to roam freely in shrimp tanks (D‐SM). White shrimp, Litopenaeus vannamei (0.50 g), was cultured as the predominant species were distributed randomly into nine fibreglass tanks (5 m³) at a density of 300 shrimp/tank, while fish (1.50 g) were stocked at the same density of 10% of the initial total shrimp biomass. The results showed that water quality parameters were not significantly different among treatments (p > .05), except for total suspended solids (TSSs). System performances based on parameters such as total weight gain (2,808.15 g/tank) and nutrient recovery were higher in D‐SM treatment (39.80% for nitrogen and 27.40% for phosphorus) than in CCT‐SM and CCT‐ST treatments (p < .05). These system performance parameters were significantly affected by the mullet‐holding strategy; however, they were not affected by fish species. The addition of mullet or tilapia in shrimp tanks did not affect shrimp growth differentially. Fish growth performances based on parameters such as final weight (98.43 g/fish) and DGR (1.29 g/day) were significantly higher in D‐SM treatment and were significantly different among D‐SM, CCT‐SM and CCT‐ST treatments (p < .05). It is concluded that in shrimp–fish polyculture with a stocking density of fish at 10% of the initial total shrimp biomass, tilapia is more effective than mullet, when caged. However, under free‐roaming conditions, the use of mullet is more effective in terms of system performances relative to a system holding caged tilapia.     

Inclusion of Amazonian Mauritia flexuosa fruit pulp as functional feed in the diet for the juvenile Pacific white shrimp Litopenaeus vannamei

This study investigated the effects of the inclusion of Mauritia flexuosa fruit pulp in the diet on the growth performance, economic benefit, muscle composition, total contents of carotenoids and flavonoids, chromaticity parameters, total antioxidant capacity, and lipid peroxidation in the hepatopancreas and muscle of the juvenile shrimp Litopenaeus vannamei (weighing 1.26 ± 0.023 g). Five diets (37% protein, 10% lipid) consisting of 0 (control), 1.25%, 2.50%, 5.00% and 10.00% (w/w) M. flexuosa fruit pulp were formulated and provided to the shrimps (n = 50 per tank, treatments in triplicate) for 31 days. Results showed that there were no significant differences between the treatments in terms of the growth capacity, chromaticity parameters, muscle composition and total flavonoid content of shrimps (p > .05). However, the carotenoid content in the muscle and hepatopancreas of the shrimps was significantly increased due to the dietary carotenoids present in M. flexuosa fruit pulp (p < .05). This increase in the carotenoid content directly favoured the increase in the antioxidant capacity in the hepatopancreas and muscle of the shrimps (R² = 0.99 and R² = 0.97 respectively; p < .05). There was also a direct relationship between the carotenoid content and the decrease in lipid peroxidation in the hepatopancreas (R² = 0.90; p < .05). The feed cost kg^?1 in terms of weight gain and protein production decreased with the inclusion of high levels of M. flexuosa fruit pulp, reaching 8.11% and 18.76% of cost reduction, respectively, with the addition of 5.00% of M. flexuosa fruit pulp. Therefore, the inclusion of M. flexuosa fruit pulp in the diets of shrimp can increase the carotenoid content and the antioxidant capacity in the hepatopancreas and muscle, reduce lipid peroxidation in the hepatopancreas, and probably provide economic benefits for the rearing of juvenile shrimps.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Effects of fish origin probiotics on growth performance,immune response and intestinal health of shrimp (Litopenaeus vannamei) fed diets with fish meal partially replaced by soybean meal

This study was conducted to evaluate the application of four fish origin probiotics to relieve the side effects induced by SBM in shrimp. Shrimps were fed with high fish meal diet (C0, positive control containing 500 g/kg FM and 0 g/kg SBM), low fish meal diet (C, control containing 250 g/kg FM and 340 g/kg SBM) or the control diet (C) supplemented, respectively, with 1.0 × 10⁸ CFU/g Bacillus pumilus SE5 (T1), Psychrobacter sp. SE6 (T2), Enterococcus faecium MM4 (T3) or Bacillus claussi DE5 (T4). After 6 weeks of feeding, the growth performance, hepatopancreatic digestive enzymes, intestinal histological structure and immune parameters were determined. The results showed that compared with high FM group (C0), significantly lower WGR and SGR as well as higher FCR were observed in the low FM group (C) (p < .05). Compared with the control, significantly lower FCR was observed in treatment T1 (p < .05), but not in treatments T2–T4. Protease, amylase and lipase activities in all the treatments (T1‐T4) were significantly higher than the control (p < .05). GOT and GPT activities in the control were significantly lower than the C0 (p < .05), while higher MDA level was recorded in the control (p < .05). Meanwhile, higher GPT activities were observed in treatments T1‐T4 compared with the control (p < .05). Compared with the C0, lower SOD, ACP and AKP activities were observed in the control. Significantly improved SOD and AKP activities were observed in all probiotic feeding groups compared with the control (p < .05). The control diet led to significant reduction of intestinal wall thickness and villus height compared with the C0 (p < .05), while significantly higher intestinal wall thickness and villus height were exhibited in all the probiotic groups compared with the control (p < .05), except intestinal wall thickness in treatment T3. Thus, these results demonstrated that the four fish origin probiotic strains could relieve the side effects induced by high level of SBM in shrimp, while probiotic B. pumilus SE5 showed the best performance.     

Integrated rearing system approach in the farming of mud crab,shrimp, fish,oyster and periphyton in bracksihwater pond

Diversification of production systems has been identified as one of the major strategies for the long‐term sustainability of brackishwater aquaculture. On the context of diversification, a 180‐day culture experiment was carried out where four farming systems were tested: monoculture of mud crab, Scylla serrata (T1), polyculture of mud crab, with mullet Mugil cephalus and shrimp Penaeus indicus (T2), polyculture of mud crab with mullet, shrimp and oyster Crassostrea cuttackensis (T3), polyculture of mud crab with mullet, shrimp, oyster along with periphyton net (T4) covering 10% of the water spread area. There was no significant difference in the growth performances of mud crab, shrimp and oyster among the treatment but a significantly higher (p < .05) final average body weight (ABW) of M.cephalus was recorded in T4 (121.19 ± 2.09 g). Production considering only the fed animals (excluding oyster) was significantly (p < .05) higher in T4 (2,115 kg/ha) compared to other treatments. The overall water quality parameters do not vary significantly (p > .05) among the treatment ponds. Although there was no significant difference in total ammonia nitrogen (TAN) and nitrite‐N, highest value was recorded in T2 (56.23 ± 39.47 µg/L and 185.53 ± 110.71 µg/L) and T1 (55.78 ± 32.26 µg/L and 180.83 ± 103.65 µg/L). The results from the current experiment based on water quality and growth of animals showed that there is no negative interaction between the mud crab and other animals stocked in the polyculture pond which indicated that polyculture provides an efficient and sustainable utilization of resources.     

An evaluation of replacing fish meal with cottonseed meal protein hydrolysate in diet for juvenile blunt snout bream (Megalobrama amblycephala): Growth,antioxidant, innate immunity and disease resistance

This study evaluated effects of fishmeal replacement by cottonseed meal protein hydrolysate (CPH) on growth, antioxidant and immunity of Megalobrama amblycephala and its resistance to Aeromonas hydrophila. Fish (average weight: 38.66 ± 0.08 g) were divided into five groups and fed with five isonitrogenous (320 g/kg crude protein), isolipidic (70 g/kg crude fat) and isocaloric (17.8 MJ/kg gross energy) diets replacing fishmeal with 0%, 1%, 3%, 5% and 7% CPH, respectively. The control diet contained 60 g/kg fishmeal. Final weight and weight gain of fish fed 5% and 7% CPH were significantly lower than that of fish fed control diet (p < 0.05). 3% CPH significantly increased total protein, globulin, acid phosphatase, C3 and C4 contents of plasma and total‐superoxide dismutase and catalase activities of liver (p < 0.05), as well as upregulated the antimicrobial peptides 1 and 2 (Leap‐1 and Leap‐2) expression levels in liver and spleen (p < 0.05). After challenge, the lowest mortality was observed in fish fed 3% CPH, and it was significantly lower than that in fish fed the 7% CPH (p < 0.05). In conclusion, dietary fishmeal replacement by 3% CPH could increase antioxidative capacity, as well as enhance immunity of fish.