Commercial Shrimp Feed Research Articles

Effects of culture salinity on growth and reproduction of the polychaete Dendronereis chipolini

Dendronereis chipolini is an important brackish water polychaete and has been wildly used as fattening feed for marine shrimp broodstocks. Investigation into the effects of salinity on performance of this worm species is fundamental for the development of mass culture procedure to produce feed for fattening shrimp broodstock and reduce pressure on wild catch. The study was conducted in a tank system with an area of 0.25 m2 in which the young worms (0.9±0.2 cm in length and 0.007±0.003 g in body weight) were stocked at 100 inds/tank. Four salinity treatments, including 15, 20, 25, 30 ppt, were designed with three replicates each. The worms were fed once a day at 9 am with commercial shrimp feed at a rate of 3% body weight. After 150 days of rearing, the fastest growth of worms was recorded in 20 ppt. The survival rate was also higher in 20 ppt but no significant difference was found (p>0.05) between treatments. Higher absolute fecundity (103,890±17,389 and 112,740±22,328 eggs/female) was recorded at 20 and 25 ppt, respectively. The males in 20 ppt also produced a higher number of sperms. Overall, the polychaete D. chipolini reared at 20 ppt performed higher growth, survival and reproduction rates.

Commercial balanced shrimp feed allows good growth, survival and immunity of snook (Centropomus spp.)

The aim of this research was to evaluate the effect of three diets based on commercial balanced food for shrimp (AB) with 28% protein, pipona (Gambusia affinis) and jumbo squid (Dosidicus gigas) on the growth, survival and blood parameters of snook (Centropomusspp.). The experiment lasted 8 weeks, it had three treatments with two repetitions (3 m3tanks) in which 10.9 g snookswere stocked, at a density of 3.3 specimens/m2, the food was applied once a day. At the end of the experiment, the specimens that received the AB diet had a total weight and length that were significantly higher than those of the other diets. Survival and percentage of lymphocytes in blood was higher with AB and jumbo squid. But, the erythrocyte count and hematocrit were lower in AB-fed fish, possibly due to the iron deficiency of this diet. It was concluded that the commercial balanced food for shrimp with 28% protein allowed good growth, survival and percentage of lymphocytes, and that if supplemented with iron it can be a good option for feeding snooks in culture.

Environmental impacts and effects on greenhouse gas emissions in shrimp feed production system for aquaculture – A case study in India

Attributional life cycle assessment study examines the environmental impact of raw materials, machinery, and unit operations. In the present work, an attributional life cycle assessment (LCA) was employed to assess the environmental and greenhouse gas impacts of a shrimp feed production system. A commercial shrimp feed mill in Tamil Nadu, India, provided inventory data for one-ton shrimp feed (functional unit) for a Cradle-to-Gate evaluation using environmental impact methodologies, specifically Impact 2002+ in SimaPro® (V9.3.0.3) software. The results showed that human health (0.003357 DALY), ecosystem quality (2720.518 PDF × m2 × yr), climate change (2031.696 kg CO2 eq), and resources (71019.42 MJ primary) were the most significantly impacted. The human health category was found to be the most prominent after normalization and weighting (0.47 pt), and strategies were suggested accordingly. The GWP20 and GWP100 measures for long-term climate change were calculated to be 8.7 and 7.33 kg CO2 eq, respectively. Cast iron used in machinery production (GWP 20–15.40%, GWP100–134.5%) and electricity use (GWP 20–6.13%, GWP 100–6.9%) accounted for sizable portions of the burden. Feed production is estimated to contribute 0.2% of global CO2 emissions within the proposed global context. These findings are significant regarding economically and environmentally sustainable shrimp feed production worldwide.

Effect of different diets on growth performance, physiological response and behavior of spiny lobster Panulirus homarus (Linnaeus, 1758)

This study aimed to know the effect of different feedings on growth performance, physiological responses, and behavioral changes of juvenile spiny lobsters. The experimental method used a completely randomized design with three treatments and four replications. There were three different feeds used as treatment, namely: flesh mussel (K), commercial fish feed (I), and commercial shrimp feed (U). Feed is given as much as 30% of body weight, five times per day at 6:30 am, 12:00 pm, 4:00 pm, 9:00 pm, and 2:00 am. The results showed that the commercial feeding of fish (I) significantly (P<0.05) increased the survival rate and biomass of spiny lobster for 54.17% and 141.7 g, respectively. While fresh mussel give better growth and stress response, but had the lowest survival rate. The results of the physiological response test of lobster were more effective in suppressing lobster stress levels than other treatments (P<0.05). The behavior of juvenile spiny lobsters showed a very striking color difference and reflex impairment scores, which indicated that the vitality of the treated juveniles (I) was better than the vitality of the treatments (K) and treatment (U). This study shows that commercial fish feed (I) is recommended for maintaining spiny lobsters in the juvenile phase, although it needs further maintenance by using an appropriate feed formulation to improve the growth performance of spiny lobsters.

Immunomodulatory Effect of Paederia (Paederia foetida Linn.) based on Phagocytic Activity of Litopenaeus vannameii

Vannamei shrimp farming usually encounters bacterial invasions. The bacteria’s attacks make the vannamei shrimp unable to be treated. Therefore, farmers must prevent the attacks by increasing their immunity. In this research, the researchers observed the immune response ability of the shrimp using the phagocytic activity of Litopenaeus vannameii as an indicator. The researchers prepared paederia flour, a mixture of commercial shrimp feed, and various formulations, starting from 0%, 10%, 20%, 40%, and 80%. The researchers determined the phagocytic activity of the mixture of Vibrio alginoliticus bacteria cells in shrimp blood. The researchers observed the phagocytosis of vannameii shrimp at 0, 10, 20, and 30 days. The results showed no significant effects of the applied treatment on phagocytosis activity. The sig-value is 0.067, with a significant confidence level of 5. The highest phagocytic activity in the treatment of Paederia addition was 40%, with the number of macrophage cells found in the phagocyte bacterial cell Vibrio alginoliticus at 41.29%.

Performance of pacific white leg shrimp fed an open-source marine resource-free diet under commercial conditions

Pacific white leg shrimp were stocked (150 PL m-3) into one of four plastic-lined 1000 m3 (0.1 ha) ponds. Ponds were randomly fed one of two diets in duplicate: a commercial shrimp feed (Grobest® Vista Eco), or an open formula, experimental, fishmeal and fish oil-free diet (F3). Shrimp were fed by hand and automatic feeders using commercial feed tables for 56 days. Sub-samples of shrimp (n = 50) were weighed weekly from each pond to evaluate growth and adjust feeding rates. Following harvest, no differences were observed between diets for survival. Combined pond biomass was 2045.0±45.96 kg (S.D.) and 2302.5±28.99 kg for commercial and F3 shrimp respectively. FCR were 1.15±0.00 and 1.03±0.01 (P< 0.05). Individual F3 fed shrimp were significantly (P< 0.05) heavier at trial termination with animals fed the commercial diet weighing 18.03±0.24 g versus 23.25±0.84 g (P< 0.05). Total hemocyte counts were 33.26±0.46 and 33.88±0.72, that for semi-granular cells 20.19±1.65 and 18.72±0.81, granular cells, 15.20±1.39 and 15.56±0.15, hyaline cells, 64.62± 3.01 and 65.72±0.96, and phenoloxidase activity, 56.87±6.12 and 50.29±0.55, for commercial and F3 fed shrimp respectively. A basic economic analysis indicated increased profitability for the F3 fed shrimp (US$7362.43 versus US$10665.62) with a return on investment (ROI) of 64.5% for the commercial feed and 89.8% for the F3 ponds. There were no differences between samples for proximate composition, cooked tail color as assessed by a BASF Salmon Color Fan or texture, as determined by a texture analyzer. Results from this trial unconditionally demonstrate the practicality of cultivating white leg shrimp using marine resource-free-based diets without impacting growth performance or consumer acceptability, while returning increasing ROI.

Excess iron supplementation induced hepatopancreas lipolysis, destroyed intestinal function in Pacific white shrimp Litopenaeus vannamei

So far, the adverse effects of excess Fe in shrimp have been ignored for years as it was thought that extra Fe supplementation was not needed in the practical diets. Nowadays, Fe concentration in commercial shrimp feed from feed enterprises could be around 301.34–545.5 mg/kg, which is mainly due to the fish meal containing up to 1500 mg/kg Fe. Therefore, the purpose of this experiment was to investigate the effects of Fe supplementation on the growth performance, tissue Fe deposition, hepatopancreas lipid metabolism, intestinal function in L. vannamei. The results showed that although growth performance was not influenced by the dietary Fe supplementation, excess Fe supplementation (955.00 mg/kg) significantly increased hepatopancreas Fe deposition and induced lipolysis. Moreover, excess Fe supplementation impaired intestinal immune function and disrupted microbiota homeostasis. These findings might provide partial theoretical evidence for the effect of dietary Fe supplementation on physiological metabolism in L. vannamei.

Application of dsRNA VP15-WSSV by Oral Vaccination to Increase Survival Rate and Response Immunes of Tiger Shrimp Penaeus monodon

Background: RNA interference (RNAi) has recently introduced as a powerful technique for specific gene silencing in antiviral therapy for controlling shrimp diseases. The present study was conducted to assess the effect of dsRNA VP15-WSSV vaccine by oral administration on tiger shrimp survival rate and response immunes. Methods: A gene encoding VP15 was isolated from tiger shrimp infected WSSV and cloned into the L4440 vector with the T7 promoter. For mass production, the pT7-VP15 gene construct was transformed to bacteria. The bacteria were inactivated using the heat-killed method by immersion and 108 cells of bacteria were mixed with 0.02 g of commercial shrimp feed for dsRNA application. The shrimp were fed by: (A) feed containing dsRNA and coated by fish oil, (B) feed without dsRNA and coated by fish oil and (C) feed without dsRNA and fish oil. The shrimp were challenged with WSSV by intramuscular injection after vaccination for two weeks. The survival rate (SR) after the challenge test was counted daily, while the THC and proPO were observed before, then on 1st, 3rd and 5th days post-challenge (dpc). Result: The survival rate of tiger shrimp for all treatments tended to decrease until the 3rd dpc, while the 4th dpc the vaccinated tiger shrimp was started to exhibit the higher SR compared to both treatments. The vaccinated tiger shrimp had significantly (P less than 0.05) higher SR and THC compared with both control treatments, but not significantly (P greater than 0.05) for proPO activity. The results indicated that the application of oral dsRNA vaccination suggested increasing in SR and response immune of tiger shrimp.

Sperm viability in wild-caught males of Macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae) fed with different diets

The relationship of body weight and length with sperm load and spermatophore weight was evaluated in wild males of Macrobrachium tenellum (Smith, 1871). In addition, the influence of a commercial and natural feed on the load and viability of sperm was determined in wild males. In 28 wild males spermatophore extraction was performed by electrostimulation 24 h after capture to analyze the relationship between body length/weight and sperm load and viability, respectively. Spermatophore weight (SW), total number (TS), dead (DS) and abnormal sperm cells (AS) were used as indicators of sperm viability. The results obtained show that there is a positive correlation between TS per spermatophore compared to body length and weight of the male. To study the effect of different diets on sperm load, three diets were employed: Diet A, commercial shrimp feed; Diet B, natural feed (mixture of squid, sardine and clam); and Diet C, combination of natural and commercial diet. To assess the initial reproductive status of the males at the beginning of the experiment, sperm viability was determined in a subsample of specimens after capture. Broodstock were fed ad libitum once a day during 70 days. TS, DS, AS and SW were evaluated. The results of the bioassay did not show differences between treatments in the parameters analyzed, except DS, which was higher in the initial group. In conclusion, the present work suggests that it is feasible to substitute fresh feed for an artificial diet for the maintenance in captivity of male M. tenellum broodstock shrimp.

Preferensi Teripang Pasir Holothuria scabra Terhadap Pakan Berbahan Dasar Makroalga

&lt;p class="Papertext"&gt;&lt;strong&gt;The Preference of The Sandfish Holothuria scabra on Macroalgae-Based Feed. &lt;/strong&gt;The sandfish, &lt;em&gt;Holothuria scabra&lt;/em&gt;, is one ofthe marine species that has the potential to be developed as a source of high-value functional food. However, the growth of sandfish is still constrained by the availability of suitable feed. This study aimed to determine the level of preference of sea cucumbers for artificial feed made from macroalgae. This study used six main ingredients: control (sea-sand), FF-1 (commercial shrimp feed), FF-2 (&lt;em&gt;Padina&lt;/em&gt; sp.), FF-3 (&lt;em&gt;Ulva&lt;/em&gt; sp.), FF-4 (&lt;em&gt;Sargassum&lt;/em&gt; sp.), FF-5 (combination). A completely randomized design with three replications was implemented. Nutritional values of feed and the sandfish body, feed consumption, specific growth rate (SGR), survival, and water quality were investigated. The results revealed that all treatments had a 100 percent survival rate, even though the SGR for all treatmentswere negative. Artificial feed made from &lt;em&gt;Padina&lt;/em&gt; sp. (FF-2) had the highest average feed consumption of 0.51 gram/day. This value was significantly greater than the other treatments (p&amp;lt;0.05). The SGR reached a positive value in the last week of the maintenance phase. The nutritional quality of the sandfish body generally decreased compared to the initial rearing condition. On the other hand, water quality was optimal for sandfish growth throughout the experiment.It can be concluded that the feed derived from &lt;em&gt;Padina&lt;/em&gt; sp. is preferable for &lt;em&gt;Holothuria scabra &lt;/em&gt;and has the potential to be further developed.&lt;/p&gt;

Evaluation of polyherbal feed supplement (Ban-V) on the enhancement of growth and non-specific immune responses in shrimp Penaeus vannamei

Owing to the growing need for eco-friendly aquaculture, usage of herbal feed supplement receives higher attention. A commercial shrimp feed supplement known as Ban-V is a unique blend of polyherbal extracts that act synergistically with each other to help in improving the immune system, protects hepatopancreas and activates several metabolic pathways for better growth and disease resistance. For that, four supplemental concentrations such as 0.5, 1.0, 2.0 and 3.0 % of Ban-V were used along with commercial shrimp feed, and feed with no supplement (control) were evaluated for 60 days. Results revealed that 2.0% of Ban-V diet fed group showed significantly increased biological performance like (average body weight, average daily growth, feed conversion ratio and survival rate) than control. The tested immunological parameters such as total haemocyte count, oxyhaemocyanin level, phenoloxidase (PO) activity, respiratory burst activity (RB), superoxide dismutase (SOD), lysozyme activity, plasma protein content (PPC) and bactericidal activity were higher in 2.0% test diet fed P. vannamei, when compared to other test and control diet fed shrimp. It is therefore suggested that Ban-V supplementation at a concentration of 2.0% was efficient in stimulating the growth and immunity in shrimp.

Evaluation of fish oil content and cottonseed meal with ultralow gossypol content on the functional properties of an extruded shrimp feed

This study aimed to analyze the extrusion processing potential of glandless cottonseed meal (GCSM) in extruded shrimp feed. Five different diets with different fish oil concentration and constant GCSM content were extruded. Extrusion temperature, screw speed, and moisture content were varied. Optimal extrudates with GCSM had 50.5 % of crude protein, which is higher than commercial shrimp feed. Mineral analyses of GCSM indicate that all minerals are within limits proposed by the authors, except iron: 0.13 compared to 0.6. GCSM is an excellent source of essential fatty acids that might meet the requirements for shrimp diets on linoleic and linolenic acids as well as highly unsaturated fatty acids. Overall results demonstrate that using GCSM as a fishmeal substitute in extruded shrimp feed might be a feasible alternative to reduce feeding costs while showing high protein, minerals, essential fatty acids, and amino acids content.

Water Quality, Growth and Feed Efficiency of White Leg Shrimp (Litopenaeus vannamei) Co-Cultured with Red Seaweed (Gracilaria tenuistipitata) Under Partial Reduction of Feeding Rates

White-leg shrimp Litopenaeus vannamei juveniles (0.95±0.03g initial weight) and red seaweed Gracilaria tenuistipitata were co-cultured in 250-L tanks for 75 days. Five feeding treatments were performed, with the control group (monoculture) being fed a commercial shrimp feed at 100% feed ration (8% of biomass per day), while shrimp in the four other groups were co-cultured with red seaweed and received commercial feed at 85%, 70%, 55% and 40% of the feeding ration of the control. The results showed that the concentrations of the TAN, NO2-, NO3-, TN, PO43-, TP, and COD in the co-culture tanks were significantly lower than in the monoculture. Survival, growth rates and production of the shrimp fed at 85%, 70% and 55% feed ration of the control were superior to those in the control group (p

Effects of environmental light colors on the larviculture of the Amazon River prawn Macrobrachium amazonicum

This study aimed to investigate the effects of red, yellow, green, violet, blue, and white light in Macrobrachium amazonicum larviculture. The trials were composed of six treatments (i.e., colors red, yellow, green, blue, violet, and white light in tanks) with four replicates each. Transparent tanks of 1 L of water, 10 salinity, and 2400 newly hatched larvae were used in trials. The larvae were fed Artemia salina nauplii and complemented with commercial shrimp feed daily. The light color affected the temperature, pH, and dissolved oxygen in the water culture and nauplii consumption, survival, and productivity of M. amazonicum. In the tanks with red light, the mean temperature was lower, while the oxygen and pH levels were higher than those with other colors. The mean consumption of A. salina nauplii was 15% higher by M. amazonicum in tanks with blue and violet light than red light. No difference in larval development was observed; however, larvae cultured under white light completed the larval cycle four days earlier than those cultured under red light. The productivity of larvae cultivated under white and violet light was 45% greater than larvae cultured under red light, and the survival was > 75%. Results indicated that M. amazonicum larval cultivation should be performed in tanks under bright light, preferably white, since other colors may negatively affect the larval development.

The Use of Mannan-oligosaccharide (MOS) to the Growth and Survival Rate of Java Eel (Anguilla b. bicolor)

Growth and survival rate are the most crucial in commercial culture as well as feed quality, and it’s pricing. This study aimed to obtain the effect of different dose of MOS to the growth and survival rate early big pencil size of shortfin eel Anguilla b. bicolor. Three replications with four treatments of feed containing 0, 0.1, 0.2, and 0.3 % doses of MOS (noted as T0, T1, T2, and T3) were administered during 84 days culture. The fish were fed with 2.2% wet basis d-1 of commercial shrimp feed combined with catfish feed. Initial density of approx. 5 kg seed stock of early big pencil eel in 0.4 m3 recirculating water system. The result indicated that absolute, individual and biomass-specific growth rate (SGRi/b) have the similar patterns corresponds to the dose of MOS. The highest SGRi was T3 (0.69±0.05% d-1) followed by T2 (0.60±0.03% d-1), T1 (0.46±0.04% d-1) and T0 (0.44±0.03% d-1). Meanwhile the SGRb shows significantly different (α < 0.05) between T3 (0.66±0.05% d-1) and T2 (0.57±0.04% d-1), but no significantly different (α > 0.05) between T1 (0.43±0.05% d-1) and T0 (0.40±0.02% d-1), and both of T3 and T2 have significantly different (α < 0.01) to T1 and T0. The best SR was in T2 (98.0 %), followed by T1 (97.5 %), T3 (97.3 %) and T3 (96.4 %). Hence, the MOS gave a positive impact on growth and slightly gave a different effect on survival rate.

The value of sea urchin, Lytechinus variegatus, egesta consumed by shrimp, Litopenaeus vannamei

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.

Policultivo del acocil (Procambarus acanthophorus) y tilapia del Nilo (Oreochromis niloticus) como estrategia de uso sustentable del agua

The crayfish Procambarus acanthophorus has a high potential for cultivation; however, it is necessary to evaluate its performance in polyculture with tilapia as a strategy for sustainable production in the rural sector where resources are limited. Goals. Assess the effect of polyculture of the crayfish and tilapia by measuring survival and growth. Methods. Three methods of cultivation with three replicates were evaluated: T1) crayfish monoculture, T2) polyculture crayfish/tilapia and T3) tilapia monoculture. Nine high-density polyethylene tanks (3 m diameter × 1.2 m deep) were used during the trial. The tilapia were fed commercial feed, 32/5% protein / lipids, while the crayfish were given commercial shrimp feed with 35/7% protein / lipids. The productive efficiency of mono- and biculture was determined based on survival feeding efficiency and growth performance. Results. Contrary to what was expected, interspecific competition, space, food availability, and weight gain of crayfish were similar in all treatments, whereas survival was influenced by the treatment, particularly during polyculture, where it was observed that tilapia affected the survival of crayfish. Unlike crayfish, tilapia maintained similar growth and survival in all treatments. Conclusions. The results indicate that polyculture of crayfish/tilapia in a recirculation system is possible and promotes the use of the water column. However, it is necessary to consider the antagonistic effect between species.

Administration of purple nonsulfur bacteria as single cell protein by mixing with shrimp feed to enhance growth, immune response and survival in white shrimp (Litopenaeus vannamei) cultivation

Single cell protein (SCP) is an alternative way to increase nutrients for animal consumption; and purple nonsulfur bacteria (PNSB) should be considered as SCP due to their rich sources of protein, vitamins and photopigments. Hence, the aim of this study was to investigate the potential of promising PNSB to be used as SCP by mixing with commercial shrimp feed for white shrimp cultivation starting from postlarval until early juvenile stages for 60 days. PNSB strains, Rhodobacter sphaeroides SS15 and Afifella marina STW181 were selected, based on high amounts of biologically complete protein and photopigments, to use as SCP at a ratio of 1:1; and their lyophilized cells at 1, 3 and 5% (w/w) were mixed well with commercial shrimp feed to obtain modified shrimp feed recipes; Diet 1, Diet 2 and Diet 3, respectively. Levels of NH4+, NO2−, NO3− and COD in rearing water from Diet 2 and 3 sets were significantly higher than control set. However, Diet 1 set showed the lowest levels of these water parameters among modified diet sets as no significant difference levels of NO3− and COD between Diet 1 and control sets. Shrimp growth performance on the basis of relative gain rate and other growth parameters found that Diet 1 set was much better than sets of Diet 2, Diet 3 and control with the lowest found in the control set. In addition, the maximum shrimp survival was observed in Diet 1 set (85%) although no significant difference among them as 80% in control set. No significant difference was found among control and all modified shrimp diets for total hemocyte count in shrimp; however, significant increases of superoxide dismutase activity found in sets of Diet 1, while phenoloxidase activity found in Diet 2 and Diet 3. The results of hepatopancreas (HP) histopathology analysis also showed a good condition of HP as healthy shrimp. PNSB biomass as SCP at optimal level has the potential to be an effective source of a novel protein in shrimp feed to enhance shrimp growth and also to increase shrimp survival as more nutritious with no effect on water quality.

Apparent digestibility of animal, plant and microbial ingredients for Pacific white shrimpLitopenaeus vannamei

A digestibility trial was conducted to determine apparent digestibility coefficients of dry matter, protein, energy and amino acids of animal, plant and microbial ingredients for Pacific white shrimp, Litopenaeus vannamei. The tested ingredients included traditional soybean meal (TSBM), PepsoyGen soybean meal (PSBM), NutriVance soybean meal (NSBM), fish meal (FM), poultry meal (PM), squid hydrolysis (SQH), scallop hydrolysis (SCH), flash dried yeast (FDY), two batches of Ulva meal (UMF and UMS) and bacteria biomass (BB). A basal diet was formulated and produced along with the experimental diets which included 300 g/kg of each ingredient and 700 g/kg of the basal diet. Juvenile shrimp (initial mean weight: 12 g, six shrimp/tank, n = 3) were stocked in a recirculation system. Apparent dry matter, protein and energy digestibility coefficients ranged from −40.11% to 78.51%, 15.17% to 97.03% and 13.33% to 82.56% among different protein sources, respectively. In general, protein and energy digestibilities in soy sources (77.6% to 97.03% and 62.77% to 82.56%, respectively) are higher than the tested animal protein (51.39% to 71.41% and 45.29% to 69.77%, respectively) and single-cell protein sources (15.17% to 53.47% and 13.33% to 40.39%, respectively). Among the three soybean sources, TSBM showed highest protein and energy digestibility. Apparent individual amino acid digestibility coefficients were also variable among different types of ingredients, and there was a reasonable correspondence to protein digestibility. The most digestible feed ingredients for Pacific white shrimp in this study were conventional soybean meal (SBM) and NutriVance soybean meal (NSBM), which indicated that these ingredients are good protein and amino acid sources for Pacific white shrimp. Resultant digestibility data may provide useful information to commercial shrimp feed industry.

The impact of organic and intensive farming on the tropical estuary

Two marine farm ponds, one practicing the organic method and the other practicing the intensive method of shrimp farming located near the Guaraíras estuary (Rio Grande do Norte, Brazil), have the potential of causing eutrophication of the estuary by disposal of excess organic matter and nutrients. Here we report nutrients, chlorophyll concentrations and stable carbon isotope ratios from the respective ponds to access differences in their potential impact on estuary water quality. Total phosphate and chlorophyll-a concentrations of pond water under the organic and intensive management method were different (i.e., 3.39 ± 0.63 μM and 17.87 ± 7.89 μM for total phosphate and 11.88 ± 9.91 μg/L and 64.46 μg/L for chlorophyll-a, respectively). With the exception of pCO2, parameters related to carbonate system also showed greater values in the organic pond compared to the intensive pond. Sediment total phosphorus concentrations were: 1.48 ± 0.13 mg/g for the organic pond and 5.99 ± 1.30 mg/g for the intensive pond. The mean stable carbon isotopic composition of the shrimp muscle tissues from the organic pond (δ13C = -17.1 ± 0.0‰) and intensive pond (δ13C = -18.2 ± 0.1‰) were very similar, despite the fact that, compared to the δ13C value shrimp tissue, the feed in the intensive pond had very different carbon isotope ratios (δ13C = -25.3 ± 0.1‰). Pond water and sediments from the intensive shrimp farm, by having a higher phosphorus concentration, have a greater potential for causing estuary eutrophication compared to the organic shrimp farm. The small range in carbon isotope ratio between the shrimps from the two types of management indicates that the commercial shrimp feed had little contribution to the biomass of the cultured shrimp in the intensive shrimp pond.