Introduction: The white shrimp, Litopenaeus vannamei has become a popular species for aquaculture worldwide due to its euryhaline nature and commercial importance. In aquaculture, the balance of nutrients in the diet of aquatic animals guarantees optimal growth and health improvement. Taurine (Tau = 2-aminoethanesulfonic acid) is an amino sulfonic acid, which has been proven to be conditionally essential for some aquatic animals when these animals are fed with diets containing high plant protein levels, due to taurine deficiency in plant-based protein sources. Tau has been also implicated in osmoregulation, modulation of neurotransmitters, hormone release, and antioxidation. Materials and Methods: A 30-day feeding study was conducted to determine the effects of supplementing the Tau in the diet of broodstock western white shrimp. Hawaiian domesticated shrimp stocks were transferred to Aquatic Research Laboratory, Persian Gulf University, from a private greenhouse pond (Delvar, Bushehr, Iran). Shrimp broodstock were disinfected with formalin (100 ppm, 30 s). Following two weeks of acclimatization to the husbandry system, the shrimp broodstock were placed in two 4000-L circular fiberglass tanks. A total of 180 shrimp broodstock with mean initial weight of 30.37 ± 2.36 g, were stocked into 18 black circular polyethylene tanks with a capacity of 250 L. Six isonitrogenous and isolipidic diets were supplemented with graded amounts of Tau including 0 (control), 2, 4, 6, 8, and 10 g/kg (T2, T4, T6, T8 and T10 respectively). To evaluate the effects of Tau on growth, body composition, digestive enzymes, and haemolymph biochemical parameters, sampling was taken at the end of the experiment. Results and discussion: The results showed that final weight, specific growth rate, weight gain, condition factor, and survival of shrimp fed with the supplemented diets with Tau had no significant differences than the control group (p>0.05). The protein content in the shrimp muscle of T6 was higher than T4 and the control group (p<0.05). The obtained results showed that hyaline cells in the haemolymph of T10 upraised, while semi-granular rate (%) decreased compared to the control group (p<0.05). However, other haemolymph indices and metabolites in the treatments fed with Tau-supplemented diets did not show significant differences compared to the control group (p>0.05). The present results showed that lipase activity upraised by increasing Tau levels in the treatments (p<0.05). The results show that the growth performance of broodstock was not influenced by dietary Tau during the shrimp maturation process. It may be attributed to the preference of the broodstock shrimp for gonadal growth rather than for somatic growth. Conclusion: The obtained results indicated that supplementing the broodstock diet with 6-10 g/kg Tau has beneficial effects on the protein content in the muscle and haemolymph biochemical indices, especially hemocyte cells and digestive enzyme activities of white shrimp broodstock during the maturation process.

A 30-day research was carried out to examine the impacts of dietary taurine (Tau) on ovaries maturation and physiological responses of Penaeus vannamei female brooders (29.4 ± 0.2 g). A basal diet (497 g kg-1 protein and 140 g kg-1 lipid) was administered with graded levels of Tau ranging from 0 (control) to 2, 4, 6, 8, and 10 g kg-1. A total of 180 shrimp brooders were stocked into 18 250 L black circular polyethylene tanks. Female (n = 5) and male (n = 5) shrimps were stocked in each tank and supplied with seawater (35.2 ± 3.1 g L-1 salinity, 28.9 ± 1.4°C) and the experimental feeds were offered to shrimp twice a day at 5% of their biomass. Supplementing diet with 4-8 g Tau kg-1 reduced latency period after eye stalk ablation to spawning (5-6 days) that was associated with higher hepatopancreatic and gonadosomatic (except for 8 g Tau kg-1 diet) indices (p < 0.05). With 10 g Tau kg-1 diet hepatopancreas glutathione peroxidase activity and total antioxidant capacity increased and catalase activity increased by 6 g Tau kg-1 diet. Supplementing diet with Tau-enhanced bile-salt dependent lipase activity in the gut. Docosahexaenoic acid and Tau levels were elevated in the ovaries with the increment of dietary Tau level (p < 0.05). Plasma total protein, calcium, cholesterol, and high-density lipoprotein increased with inclusion of 6-10 g Tau kg-1 diet. The transcription levels of vitellogenin, insulin-like growth factor II, superoxide dismutase, prophenoloxidase, and lysozyme genes transcription levels were upregulated in the hepatopancreas of shrimp brooders fed 6-10 g Tau kg-1 diet (p < 0.05). It seems that Tau at 4-8 g kg-1 diet by modulating lipid metabolism, antioxidant capacity, and immunocompetence can improve maturation and health status of P. vannamei brooders.

Arachidonic acid (AA) is an essential fatty acid that has vital influences on early development in marine fish larvae. In this regard, a 30-day research was run to examine the effects of live food enrichment with graded levels of AA on some physiological responses of Acanthopagrus latus larvae. Four experimental emulsions containing four levels of AA were used to enrich live foods (rotifer and Artemia), including very low (6

This experiment was conducted to compare water quality, growth performance, body composition, and insulin growth factor gene expression of Pacific white shrimp, Litopenaeus vannamei , reared under different stocking densities (100, 200, 300, and 400 shrimp m- 3) in a biofloc system with zero-water exchange for nine weeks. The results demonstrated that all the water quality variables remained within the acceptable range that are presumed to be safe levels for Pacific white shrimp farming. The weight gain ratio and specific growth rate of shrimp reduced by increasing the stocking density to the lowest values of 2800.00 +/- 105.32 % and 5.34 +/- 0.11 % d-1 , respectively, in shrimp reared under the highest stocking density (400 shrimp m- 3). The highest feed conversion ratio was also obtained under the highest stocking density of shrimp (P < 0.05). A significant decreasing trend of the insulin growth factor-1 gene expression was observed by increasing the shrimp stocking density (P < 0.05). The final yield of shrimp in the present study significantly increased by increasing the shrimp stocking density and reached the maximum value of 3.05 +/- 0.21 kg m- 3 at the highest stocking density. There was no significant difference in the carcass composition of the shrimp among the experimental treatments (P < 0.05), except for lipid content which was significantly higher in shrimp reared under the lowest stocking density (100 shrimp m-3) (P < 0.05). Findings of the current study confirmed a clear effect of stocking density on growth perfor-mance of the Pacific white shrimp with the recommended density of 400 shrimps m- 3 to achieve the maximum yield, while the stocking density of 100 shrimps m- 3 is feasible to reach the highest weight gain and probability of Pacific white shrimp cultured in a biofloc system with zero-water exchange for the present experimental condition, genetics used and nutrition supplementation.

Abstract In the present study, the effects of dietary supplementation of low molecular weight sodium alginate on growth, body composition, anti-oxidant enzymes, digestive enzymes, and immune response in yellowfin sea bream juvenile (Acanthopagrus latus) were investigated. Fish (n=180) were divided into 3 groups with 3 replicates and received dietary treatments including basal diet without sodium alginate (control treatment), basal diet containing 5 g sodium alginate per kg diet (0.5% treatment), and 10 g sodium alginate per kg diet (1% treatment) for 8 weeks. The results showed that the final weight, weight gain, specific growth rate, condition factor, feed conversion, and protein efficiency ratios did not reveal a significant improvement compared to the control treatment (P>0.05). The obtained results indicated that dietary sodium alginate did not affect body composition (P>0.05). The activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in the groups fed on 0.5 and 1% sodium alginate showed a significant increase (P<0.05) compared to the control group. But, the activity of lipid peroxidation (MDA) in the groups fed on 0.5 and 1% sodium alginate showed a significant decrease (P<0.05) compared to the control group. The digestive enzymes increased significantly (P<0.05) by supplementation of sodium alginate, compared to the control group. Mucus lysozyme and complement activity were not significantly different (P>0.05). Overall, it can be concluded that feeding of yellowfin sea bream on the diet supplemented with 0.5 and 1 percent sodium alginate for a period of 8 weeks does not enhance the non-specific immune response and growth. Nonetheless, sodium alginate improved the activity of the antioxidant and digestive enzymes, indicating the positive effects of sodium alginate on enzymatic responses.

The marine fish larvae mostly rely on livefeed, with certain nutritional deficiencies such as poor long chain fatty acids, in spite of recent progress in developing artificial feed. Thus, the present experiment was conducted to evaluate a 30-day dietary effects of enriched rotifer (Brachionus rotundiformis) and Artemia nauplii (Artemia franciscana) with docosahexaenoic acid (DHA) on performance of yellowtail sea bream (Acanthopagrus latus) larvae. For this purpose, 60,000 larvae from wild broodstocks were stocked in 12 tanks (50 larvae/L) supplied with green water (0.5 ×106 cell/ml Nannochloropsis. sp). The rotifer and Artemia were enriched with four experimental emulsions contained four levels of DHA including very low (6 %, DHA-VL), low (12 %, DHA-L), medium (24 %, DHA-M) and high (37.8 %, DHA-H). Larvae were fed with rotifers from day 2–20 post hatch (DPH) and Artemia metanauplii (Instar-II, from 16 to 30 DPH). After the 30-day dietary trial, survival rate and growth performance of larvae were found not affected by different levels of DHA (P > 0.05). The activity of digestive enzymes including total proteases, lipase, amylase, alkaline phosphatase, and leucine-alanine peptidase showed some fluctuations among the experimental groups. However, in the most of the sampling intervals, except for protease activity, the activity of digestive enzymes did not change significantly among the experimental groups. The n–3 polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and DHA, were the highest in the whole body of larvae from DHA-M treatment. The DHA/EPA ratio in the whole body of larvae was significantly increased with increasing DHA level (P < 0.05). Based on our findings, very low levels of DHA is enough for supporting normal growth, survival and metamorphosis in developing A. latus larvae up to 30 days post hatching.

Dunaliella salina is well-known for its ability to accumulate high amounts of carotenoids when cultivated under high salinity and high irradiance. However, as with all microalgae, cultivation processes are expensive when synthetic fertilizers are used for cultivation. In this study, we assessed the feasibility of utilizing anaerobic digestate of food waste as a source of nitrogen for the cultivation. Dunaliella salina MUR 8 was cultivated in F-medium with partial to complete replacement of the nitrogen (0–100% digestate nitrogen) source under high salinity (150–250‰) conditions to study both cell growth and carotenogenesis. Further investigation of the physiological response of D. salina was performed under varying irradiance and temperature levels. Maximum growth rate of 0.141 ± 0.022 day−1 and carotenoid content of 3.53 ± 0.47 mg g−1 were achieved at 150‰ salinity and under mild irradiance of 180 µmol photons m−2 s−1, in medium where nitrogen was completely replaced with food waste digestate nitrogen. Higher irradiance above 400 µmol photons m−2 s−1 and higher salinity had combined negative effects on growth and carotenogenesis, reducing growth rate and carotenoid content to 0.047 ± 0.01 day−1 and 1.797 ± 0.37 mg g−1, respectively, due to the NH3–N species present in the digestate. However, under increased irradiation and temperature, in comparison with cultures grown in synthetic medium with nitrate salts as nitrogen source, there was no significant difference in biomass productivity when the strain was cultivated using food waste digestate as sole nitrogen source.

A 56-day research was conducted to assess the influence of dietary protein content and carbohydrate: lipid ratio on growth performance, hematological parameters, intestinal histoarchitecture and digestive enzymes activities of orange-spotted grouper (Epinephelus coioides) juveniles (13.7 g). Four experimental diets were designed with various protein, lipid and carbohydrate levels namely LP-LCL (low protein 40%-low carbohydrate: lipid ratio=1.4), HP-LCL (high protein 48%-low carbohydrate: lipid ratio=1.4), LP-HCL (low protein 40%-high carbohydrate: lipid ratio=2.9) and HP-HCL (high protein 48%-high carbohydrate: lipid ratio=2.9). Fish were stocked into twelve 300-L cylindrical polyethylene tanks (15 fish in each tank) and fed with experimental diets. The low carbohydrate: lipid ratio diets improved growth rate of the fish. The lipid content of the whole body increased with decreasing dietary carbohydrate to lipid ratio. The intestinal folds' length and thickness significantly increased in the low carbohydrate: lipid ratio treatments. The intestinal total alkaline protease activity elevated by increasing dietary protein content, meanwhile the activities of lipase and amylase increased with increasing dietary lipid and carbohydrate levels, respectively. Blood hematocrit decreased but hemoglobin increased by increasing dietary carbohydrate to lipid ratio. According to the results dietary lipid is more preferable than carbohydrate as an energy source for orange-spotted grouper juveniles and induces protein sparing effect in a low protein content diet.

The study of the antimicrobial activity of colloidal silver nanoparticles against Bacillus spp and Vibrio harveyi and their gtrowth kinetic assay

Microalgal cultivation is currently stifled by various constraints. In winter, additional losses are incurred due to lower productivities. Here, effects of medium recycling to conserve water use, paddle wheel mixing duration to reduce power consumption and culture depth on growth of Dunaliella salina (MUR 8) cultivated in raceway ponds during the Austral winter season was studied. Ponds were operated semi-continuously at 0.18 m depth to study the effect of medium recycling on the growth and productivity. One pond served as a control without recycling (NMR) which was replenished with fresh medium after each harvest while the other served as a test variable with medium recycling (MR). In parallel, two ponds were also operated to investigate the effects of culture depth on the growth and productivity with one pond being operated at of 0.11 m (LD) and the other at 0.18 m (HD). Subsequently, a comparison of 24 h paddle wheel mixing (24MX) against 12 h daytime paddle wheel mixing (12MX) was also performed in 2 m(2) raceway ponds. Our results showed that medium recycling, paddlewheel mixing time and pond depth did not have significant effects on mu(max), biomass, lipids, and carotenoid productivity of Dunaliella salina. However, carotenoids: chlorophyll a ratio were significantly higher in LD treatments in comparison with HD treatments. Areal productivities were also higher in HD treatments compared to LD treatments. Medium recycling, paddlewheel mixing time and pond depth also had no significant effect on the photosynthetic parameters: F-v'/F-m ', rETR(max) and I-optimum. However, alpha was higher in HD treatments compared to LD treatments. NPQ(max) was also higher in 24MX treatments compared to 12MX treatment. In here we demonstrated that medium recycling and reduced paddle wheel mixing could be employed as viable cost and energy saving methods in the cultivation of Dunaliella salina during the Austral winter season.

Sixty-day research was conducted to investigate the effects of dietary butyric acid glyceride (BAG) on the performance of Acanthopagrus latus fingerlings (8.59 +/- 0.33 g). Experimental feeds were prepared by supplementing a commercial feed (crude protein: 50%, crude lipid: 15%) with graded levels of BAG including 0 (control), 0.25% (BAG0.25), 0.5% (BAG0.5) and 1% (BAG 1). One hundred and twenty fish (10 fish in each tank) were stocked in twelve 300-L tanks then fed with the experimental feeds twice daily. Growth and feed utilization in fish fed BAG-supplemented diets were better than the control (p < 0.05). Fish fed BAG1 diet had more red and white blood cells counts than the other groups. Total immunoglobulin content and lysozyme activity in the skin mucus increased by increasing dietary BAG. Fish in BAG1 group had more skin mucosal alternative complement pathway activity than the other groups (p < 0.05). Liver catalase and glutathione S transferase activities increased in a dose-response manner to dietary BAG level. Fish in BAG1 group showed higher liver glutathione reductase activity than the other treatments. According to the findings of this study, supplementing diet with 1% of BAG can promote growth performance and health conditions in A. latus fingerlings.

The respiratory trees present only in the class Holothuroidea and the rest of the echinoderms lack it. Only some holothurian species have the ability to regenerate their respiratory trees after autotomy. Therefore, respiratory trees could be considered as a suitable model to assess the regeneration mechanisms in animals. In the present study, the respiratory tree regeneration after posterior evisceration were examined in Holothuria parva during 75 days. Since autotomy reduces antioxidant defense in the organisms, in the present study alterations of antioxidant enzymes were also evaluated during the experiment. H. parva is the dominant intertidal species distributed in the north of the Persian Gulf. In the present study, H. parva ejected the left respiratory tree, the digestive tract and supportive mesenteries from the anus, about 1-2 min after potassium chloride injection. The closure of the opening at the posterior ends of the body was the first reaction to the injury. Seven days after evisceration, the small bud formed on the dorsal side of the cloaca which was covered with the coelomic epithelium of cloaca. The coelomic epithelium started to proliferate to undifferentiated cells on the apex of the buds. The primary respiratory tree consisted of the luminal cuboidal epithelium and thin connective tissue surrounded by the slender coelomic epithelium. This preliminary organ was observed at the apex of the buds, 13 days after evisceration. Gradually, myoepithelial cells arranged around a longitudinal axis and formed a circular muscle. The primitive branches of primary respiratory tree started to form 18 days after evisceration. Forty days after evisceration, the luminal epithelium of the respiratory tree had the same appearance as the intact luminal epithelium. The regenerated respiratory tree was histomorphologically very similar to an intact respiratory tree 56 days postevisceration, but unlike that, it was not yet wrapped around the intestine and was completely separate from it. Despite the development of the regenerating respiratory tree, no wrapping around the intestine was observed until the end of the experiment. According to the results, the activity of the catalase (CAT) and superoxide dismutase (SOD) in the muscle homogenate was significantly higher than the control 5 days after evisceration. The CAT and SOD levels gradually decreased in eviscerated animals. The lipid peroxidation level followed a decreasing trend in the eviscerated animals during the experiment. However, its value reduced to the control level at the end of the experiment.

In the present study, the regeneration process following posterior evisceration along with changes in antioxidant enzymes during regeneration in Holothuria parva was investigated for the first time. In the present study, evisceration was induced after molecular and morphological identification of the species. Most of the digestive tract and the left respiratory tree were removed from the body through the anus. The tissue regeneration of the digestive tract and changes in the activity of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO)] were examined during 75 days. According to the results, evisceration in this species was from the anus and the regeneration process could be divided into four steps based on the histomorphological alterations. The digestive tract grew in the form of a straight cord from the anterior end to the cloaca. During the regeneration process, several cavities were created inside the cord, which gradually joined to form a continuous lumen. For the first time on the 24th day after evisceration, food was found in the digestive tract. Fifty days after evisceration, the tissue structure of different parts derived from regenerated digest tract was found to be similar to that in the intact digestive tract. According to the results, 5 days after evisceration the activity of CAT and SOD in the regenerated digestive tract was significantly higher than in the control. The CAT and SOD levels gradually decreased in the regenerated digestive tract, although by the end of the experiment it was significantly higher than in the control group. The LPO level in eviscerated animals showed a decreasing trend during the experiment and its value decreased to the control level at the end of the experiment.

A 30-day study was carried out to determine the influence of different weaning strategies (WS) on growth and survival rates, stress resistance, digestive enzyme activities and whole body fatty acid profiles in yellowfin seabream (Acanthopagrus latus) larvae. Thus, eight WS were designed by combining live foods (LF) (rotifers and Artemia) and a microdiet (MD) (Gemma Micros, Skretting). In the control group (100 LF), larvae were fed only LF (100%), including enriched rotifers (from 2 to 20 days post hatching, dph) and Artemia (nauplii + enriched metanauplii, from 18 to 30 dph). The other treatments were based on different proportions of LF with the MD: 75LF-25MD, 50LF-50MD, 25LF-75MD and 100 MD in which 25, 50, 75 and 100% of LF that applied in the control group were replaced with a fixed ration of MD, respectively. In addition, for determining the appropriate time of weaning, three WS were applied including: sudden weaning (SW): larvae were weaned on to MD with only rotifer from 2 to 5 days post hatch (dph); early weaning (EW): larvae were weaned on to MD with only rotifer from 2 to 14 dah and late weaning (LW): larvae were weaned on to MD with rotifer (from 2 to 14 dph) and Artemia nauplii (from 12 to 20 dph). Larvae were hand-fed with the MD hourly from 08:00 h to 18:00 h (11 times a day). Results showed that the lowest survival rates were found among larvae from 100MD (1.5%) and SW (1.9%) groups, whereas the highest survival rates were found in larvae from 100LF (31.0 ? 1.7%), 75LF-25MD (34.7 ? 4.5%) and 50LF-50MD (36.2 ? 4.0%). Larvae from the 50LF-50MD group showed the highest resistance against air exposure (70.0%) and osmotic stress (100.0%) challenges. At the end of the trial, larvae from 100LF, 75LF-25MD, 50LF-50MD and LW groups showed higher growth performance than the other groups. At 30 dph, larvae from the LW group had the highest level of alkaline phosphatase to leucine-alanine peptidase ratio, while those from the 100MD, SW and EW treatments showed the lowest ones. The fatty acid profile of larvae reflected that of the diet. In particular, larvae from 100MD and SW groups had generally lower levels of n-3 long chain polyunsaturated fatty acids compared to the other treatments. In conclusion, results of the present study indicated the time of weaning and proportion of LF and MD remarkably affect larvae performance in terms of growth, survival, digestive function and stress tolerance. In addition, the replacement of LF with MD up to 50% after mouth opening of larvae neither have detrimental effects on growth, survival and digestive enzymes activities, meanwhile enhanced stress resistance of A. latus larvae.

A 56-day nutritional research was performed to examine the influence of alternative vegetal protein and lipid sources on performance of yellowfin seabream fry (Acanthopagrus latus) (0.5 +/- 0.0 g). In this regard, five isoproteic (Ca. 500 g/kg) and isolipidic (Ca. 150 g/kg) diets were formulated in which fish meal (FM) and fish oil (FO) were simultaneously replaced with blends of plant proteins (PP, soybean meal and corn gluten) and vegetal oils (VO, canola and soybean oils) at 20% (SR20), 40% (SR40), 60% (SR40) and 80% (SR80) levels, respectively; meanwhile, a control diet (SR0) was formulated based on FM and FO. Growth and feed utilization were not influenced by experimental diets. The fatty acid profile of fillet drastically altered by dietary treatments. Fish fed with the SR60 and SR80 feeds had higher total protease, trypsin and alpha-amylase activities than other treatments. The antioxidant enzyme activities and glutathione content in liver were enhanced in fish fed with the SR40, SR60 and SR80 diets. Skin mucosal immune parameters including total protein content, alkaline phosphatase and alternative complement pathway activities in the control group were relatively lower than the vegetal treatments. According to these results, it is recommended that 410 g/kg of FM and 45 g of FO/kg can be replaced with alternative vegetal sources in diet for A. latus fry.

An 80-day feeding trial was conducted to evaluate the influence of different short-term fasting and re-feeding strategies on growth and physiological responses in yellowfin seabream, Acanthopagrus latus (2.4 +/- 0.2 g) fingerlings. The fish were subjected to four different feeding regimes, and the control group fed four times daily to apparent satiation throughout the whole feeding period, while the other three groups were deprived for 2, 4 and 8 days followed by 8, 16 or 32 days of re-feeding (F2R8, F4R16 and F8R32, respectively) in repeated cycles for 80 days. The fish in the control and F2R8 groups had the highest and the lowest total length, respectively (p < .05). Moreover, fish exposed to F4R16 had the highest hepatosomatic indices, while control fish had the lowest hepatosomatic indices (p < .05). Fish in the F2R8 group relatively had higher catalase and glutathione-S-transferase activities than other groups (p < .05). Furthermore, total protease, alpha-amylase and alkaline phosphatase activities in the F4R16 and F8R32 were higher than the F2R4 and control groups (p < .05). Overall, this study showed that compensatory growth in weight and length and digestive enzyme activities were observed in the F4R16 and F8R32; however, the increase in the activity of antioxidant enzymes in the F8R32 group indicated that oxidative stress remained after 80 days of re-feeding in the liver.

A 6-week study was conducted to assess the effect of dietary fishmeal (FM) replacement with Sargassum ilicifolium meal (SIM) at four substitution levels including 0 (control), 3% (S3), 6% (S6) and 9% (S9) on performance of Asian sea bass ( Lates calcarifer ) juveniles (initial mean body weight of 29.0 ± 1.0 g). Growth performance pronouncedly increased in SIM-supplemented groups compared to the control ( p  < .05). Fish fed on the S6 diet had higher pancreatic digestive enzyme activities than other treatments. Supplementing diet with SIM remarkably enhanced red blood cell count compared to the control. Moreover, fish in the control and S3 groups had higher lymphocyte, but lower neutrophil percentages than the S6 and S9 treatments ( p  < .05). The greatest and the least amounts of the total protein and total immunoglobulins (Ig) in serum were found in the S6 and the control, respectively. The amount of alternative complement pathway activity in the serum of fish in the S9 group was higher than the other groups, whereas higher serum lysozyme activity was found in the S6 and S9 treatments compared to those in the control and S3 groups ( p  < .05). Total Ig content of the skin mucus in the S6 and S9 groups was higher than the control. The greatest and the least mucosal lysozyme activates were found in the S6 and control, respectively ( p  < .05). The liver superoxide dismutase activity in the S6 and S9 groups was higher than the other treatments ( p  < .05). The insulin-like growth factor-1 mRNA transcript abundance levels in the liver were greatest and the least in fish fed on the S9 and control, respectively. The expression of lysozyme gene, as indicated by an abundance of mRNA transcript for lysozyme , in the liver was higher in the S6 and S9 groups than the other groups ( p  < .05). Furthermore, fish fed the SIM-incorporated diets had higher interlukine-1β mRNA transcript abundance in the liver compared to the control ( p  < .05). Overall, according to the findings of this study 6% of dietary FM could be replaced with SIM to improve growth rate and health status in L. calcarifer juveniles.

A 15-day study was conducted to evaluate the effects of Artemia metanauplii enriched with two commercial supplements (Easy DHA-Selco and S. presso) which contained high levels of n–3 long chain polyunsaturated fatty acids (n–3 LC-PUFA) on growth performance, stress resistance and fatty acid profile of Litopenaeus vannamei post larvae (PL). In this regard, PL were fed with three different types of Artemia including: (1) newly hatched Artemia franciscana nauplii as the control group; (2) Artemia metanauplii enriched with Easy DHA-Selco; and (3) Artemia metanauplii enriched with S. presso. Survival rates did not change among different groups. PL fed Artemia enriched with the S. presso and the Easy DHA-Selco showed the highest wet and dry weight, respectively (p<0.05). Moreover, PL fed Artemia enriched with the commercial emulsions had higher survival rate (~ 10 %) than treatments fed newly hatched Artemia (p<0.05).The concentration of n–3 PUFA especially DHA and also n-3 / n-6 PUFA ratios were higher in PL fed with Artemia enriched with the commercial emulsions than the control group. Feeding enriched Artemia with n–3 LC-PUFA is recommended to improve growth performance in larval stages of L. vannamei.

ABSTRACT A 15-day study was conducted to evaluate the effect of enrichment of Artemia metanauplii with four different emulsions, including: (A) Easy-DHA Selco; (B) Easy-DHA Selco + L-lysine (4 g/L); (C) Easy-DHA Selco + DL-methionine (4 g/L); and (D) Easy-DHA Selco + L-lysine (2 g/L) + DL-methionine (2 g/L) on growth and stress resistance of white leg shrimp Litopenaeus vannamei larvae (from Mysis I to postlarvae12). It is noticed that shrimp PL in group B had the highest wet (36.1 ± 3.1 mg) and dry (1116.7 ± 60.0 µg) weights as well as stress resistance to fresh water (64.0 ± 5.5%).

Cathepsins represent a major component of the lysosomal proteolytic system and, as such, are responsible for intracellular protein degradation. The aim of this study was to evaluate the cathepsin-L (CTSL) gene expression changes and growth factors in Litopenaeus vannamei under various biofloc systems (BFT) and different protein levels. Four bioflocs were used: BFT fed diets of 25% CP and spoilage palm date extract (P25), diets of 25% CP and molasses (M25), diets of 15% CP and spoilage palm date extract (P15), diets of 15% CP and molasses (M15) and clear water without biofloc fed with 38% CP (Control) that were performed in triplicate. A 35-day study was conducted with 35 juvenile (average 5.37±0.33 g) shrimp randomly stocked in fifteen 300 L tanks at a stocking density of 175 shrimp m−3. Real time PCR technique was used to estimate the effect of biofloc on the CTSL gene expression in shrimp hepatopancreas and Beta actin gene was used as an internal control gene. In all the biofloc treatments, a significant increase in the expression of CTSL gene was observed (P 0.05). Moreover the highest growth parameters (weight gain, better feed conversion ratio (FCR), growth rate and survival) was showed in P25 and the lowest in the control (P 0.05). It seems the biofloc technology with its positive effects on digestion and immunity provides the basis of increasing the CTSL gene expression in this species.