Increased carbon and nitrogen supplementation in Artemia culture ponds results in higher cyst yields

This paper studied the effects of increased carbon (C) and nitrogen (N) supplementation in pond production of Artemia franciscana cysts in southern Vietnam. Pig manure and tapioca were used to supplement the natural food of Artemia in the ponds at a fixed C/N ratio 10. Addition of pig manure and tapioca at a standard rate (0.210 kg ww and 0.319 kg dw pond^?1 day^?1, respectively) was used as control. Increasing amounts of supplementation (110, 115, and 120 % of the control) were applied in three treatments. During the 6-week culture period, extra C and N supplementation resulted in a better growth, faster maturation, and higher fecundity of Artemia when compared to the control. Total cyst production was the highest (9.96 kg ww ha^?1) at the supplementation level 10 % higher than the control; the lowest cyst production was found in the control (2.84 kg ww ha^?1). Increasing the supplementation of C and N at levels 110, 115, and 120 % of the control at C/N ratio 10 may have stimulated the formation of bioflocs in the hypersaline Artemia ponds and helped to improve conditions for increasing cyst yields.     

Yield and Economic Efficiency of Green Water in Combination with Supplemental Feeds for Artemia Production in Vietnamese Salt Ponds

We evaluated the combined effects of different green water sources and feed supplements on Artemia biomass production and economic efficiency. A two-factor experiment was set up with two green water types produced from the ratios of nitrogen and phosphorus (N:P = 5 and N:P = 10) in combination with two types of supplemental feed (rice bran or pig manure). After 12 weeks of culture, total Artemia biomass yield with the N:P = 5 treatment (2.29 ton ha^?1 crop^?1) was 14% higher than that with the N:P = 10 treatment (1.97 ton ha^?1 crop^?1), although this difference was not significant (P > 0.05). There was no significant interaction between green water and supplemental feeding treatments for the final yield of Artemia biomass. Comparative cost-benefit analysis showed that the treatment of N:P = 5 combined with pig manure attained a significantly higher net profit and cost/benefit ratio than the other treatments.     

不同卤虫混养比例对生物絮凝系统凡纳滨对虾标粗效果的影响

在生物絮凝凡纳滨对虾养殖系统中,分别以100%、50%、0%的比例投喂活的卤虫幼体(Artemia spp)和饲料(分别记为A组,AF组和F组),研究其对养殖过程中氮素转化途径及转化效率的影响。卤虫以湿质量计算,饲料以干质量计算。试验结果显示,A组亚硝酸盐浓度显著低于另外2组(P<0.05);各组氨氮浓度在养殖第7天时达到峰值,此后迅速降低并维持在1 mg/L以下,3组之间差异不显著(P>0.05);3组硝酸盐浓度均无积累,且略有下降;养殖30 d后,A组对虾存活率(35.67%)显著高于其余两组(均低于30%)(P<0.05);A组对虾终末平均体质量为(1.92±0.96)g,显著低于AF组的(2.99±1.85)g和F组的(3.25±1.23)g(P<0.05),原因可能是卤虫的营养成分相比配合饲料较为单一。     

Effects of bioflocs on water quality,and survival,growth and digestive enzyme activities of Litopenaeus vannamei (Boone) in zero‐water exchange culture tanks

A 30‐day experiment was performed to investigate the effects of bioflocs on water quality, and survival, growth and digestive enzyme activities of the white shrimp Litopenaeus vannamei. Altogether 28 shrimp (7.4 ± 0.1 g) were stocked in each 150 L tank. Two bioflocs treatments and one control were managed: ‘bioflocs 1’ and ‘bioflocs 2’ based on two different densities of the bioflocs, and clean water control without the bioflocs. Brown sugar was added to the bioflocs 1 and bioflocs 2 treatment tanks accounting for 28% and 80% of the shrimp feed respectively (corresponding to proximate C/N ratios of 10 and 14 in daily additions of organic matter respectively), so as to promote bioflocs production and approximately 14 mL L^?1 in treatment bioflocs 1 and 20 mL L^?1 in treatment bioflocs 2 were maintained from day 15. Monitoring of selected water quality parameters throughout the whole experiment period showed that all parameters remained within recommended levels for shrimp culture in the bioflocs treatments at zero‐water exchange, especially low total ammonia nitrogen and nitrite nitrogen levels. By the end of the experiment, shrimp survival rates were above 86%, with no significant differences (P > 0.05) among the three groups. Both weight gain rate and special growth rate tended to increase in the bioflocs treatments compared to those in the control. Meanwhile, the overall specific activities of protease, amylase, cellulase and lipase of the shrimp in the bioflocs treatments were all higher than those in the control; and for the specific activity of the same digestive enzyme, the differences between the bioflocs treatments and the control performed inconsistently among different organs: hepatopancreas, stomach and intestine. Present results suggest that the bioflocs can not only maintain favourable water quality conditions for shrimp culture and help shrimp grow well in zero‐water exchange culture systems, but may also have a positive effect on digestive enzyme activities of the shrimp.     

Contribution of bioflocs to the culture of <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> post-larvae determined using stable isotopes

The aim of this study was to use preselected quality indicators for Litopenaeus vannamei post-larvae and the stable isotopes technique with δ¹³C and δ¹⁵N to determine the influence of bioflocs in shrimp feeding during the nursery phase, between PL1 and PL30. A control treatment (CT) with water renewal was compared to a biofloc treatment (BT) that received organic carbon fertilizations. Different types of commercial feed (Stresspak and Flake-INVE?, PL40-GUABI?), microalgae (Chaetoceros muelleri) and Artemia sp. nauplii were used as food sources. The physical and chemical parameters of water and ammonia were monitored daily, and nitrite, nitrate and alkalinity were measured weekly. Suspended solids and the microorganisms of bioflocs were characterized. At the end of the experiment, fifteen shrimps of each replicate were collected to evaluate nine larvae quality indicators. Isotopic values of ¹³C and ¹⁵N of food sources and shrimp tissues were collected on days 10, 20 and 30, and a Bayesian model of isotopic mixture measured the contributions of these sources to the shrimp biomass. Salinity, alkalinity and nitrite differed significantly between the treatments but were appropriate for post-larvae production. The larvae quality conditions in the CT treatment were ranked as “good,” whereas the BT conditions were considered “excellent” according to the analysis of larval quality parameters. The stable isotopes analysis showed that the PL40 GUABI? feed was the most important food source throughout the experimental period in the CT. In the BT (10th and 20th days), the bioflocs and commercial feeds (Flake-INVE?, PL40-GUABI?) did not present significant variations in their contribution ratios; however, on the 30th day, the contribution of the PL40-GUABI? feed was higher when compared to bioflocs. In general, the commercial feed played a more important role as a food source for Litopenaeus vannamei larvae during the nursery phase, although the consumption of bioflocs led to a better larvae quality.     

Carbon supplementation and microbial management to stimulate artemia biomass production in hypersaline culture conditions

Two Artemia culture experiments were conducted in a zero water exchange system at salinity 80 g L^?1. In Experiment I, different carbon sources including molasses, glucose, sucrose and corn flour were given to supplement suboptimal feeding with the microalgae Dunaliella viridis, whereas the control was fed only D. viridis. In Experiment II, molasses was supplemented to the culture medium, as well as the bacteria Alkalibacterium sp. or the archaea Halobacterium sp., isolated from the brine in the local saltponds. The control groups were fed only with D. viridis or with D. viridis and molasses. Our study shows that in laboratory culture biofloc development can be stimulated under hypersaline conditions. Supplementation of carbon sources, bacteria and archaea benefited biofloc development, water quality in terms of nitrogen load and enhanced Artemia production. Denaturing gradient gel electrophoresis analysis on the bioflocs also indicates an increased biodiversity and richness of the microbial community in the culture medium. These results need to be confirmed for large scale Artemia pond production, in which case, we recommend molasses as carbon source.     

Growth of Chaetoceros calcitrans in Sediment Extracts from Artemia franciscana Culture Ponds Points to Phosphorus Limitation

Chaetoceros calcitrans is one of the most suitable algal strains to feed Artemia because of its appropriate size, digestibility, absence of toxins, and nutritional value. Apart from light and temperature, the growth of C. calcitrans in Artemia ponds in the Mekong Delta of Vietnam depends on the supply of nutrients, especially nitrogen (N) and phosphorus (P) released from the pond bottom sediments. This study was carried out to investigate the growth of C. calcitrans in relation to the availability and proportions of N and P present in the extracts of Artemia pond bottom sediments. The results show that the sediments are depleted in dissolved reactive P (DRP) and highly unbalanced in terms of the ratio of dissolved inorganic N (DIN) to DRP. Algal density and biomass were significantly higher in the extracts with DRP concentrations above 0.1 mg P/L and DIN/DRP ratios below 100.     

Responses of phosphate solubilizing bacteria to qualitatively different fertilization in simulated and natural fish ponds

The growth of phosphate solubilizing bacteria (PSB) was examined inresponse to pond fertilization with poultry dropping (PD) (12,500 kgha^–1 y^–1), cattle manure (CM) (25,000 kg ha^–1 y^–1), inorganic fertilizer (IF) consisting of urea (10.83 kg ha^–1 y^–1) and single super phosphate (43.52 kg ha^–1 y^–1) and inorganic-organic mixed fertilizers (PD:CM:IF – 1:1:1) in simulated fish ponds under alluvial and laterite soil conditions as well as in natural pondslocated in alluvial soil zone. The high correlation between dissolved oxygenand density of PSB implied the contribution of the latter in the aerobicorganic decomposition. The PSB were maximal in the PD, and minimal in theIF treatments. The distribution pattern of PSB was related to theautochthonous C/N ratio and the N/P ratios of water. Relatively low C/N ratios caused greater abundance of PSB. Increased fish production in PD treatments was clearly due to increased primary productivity and higher zooplankton abundance resulting from nutrient-grazing-detritus-microbial-food chain complex pathways.     

Evaluation of nitrogen cycling and fish production in seasonal ponds (‘Fingerponds’) in Lake Victoria wetlands,East Africa using a dynamic simulation model

A dynamic model was developed to simulate nitrogen (N) flows and fish production in seasonal wetland fish ponds (Fingerponds) based on organic manuring and natural food production. The model incorporates pond water depth, food availability, fish stocking densities, fish and fingerling weights at stocking, reproduction rate, manure type and application rates. The ponds were fertilized fortnightly with 1042 kg ha⁻¹ chicken manure. The model captured the dynamics of hydrology, nutrients and fish and demonstrated that similar fundamental processes underlie fish production in these systems. The model predicted annual fish yields of up to 2800 kg ha⁻¹. Simulated fish production, chlorophyll a and dissolved inorganic N concentrations were comparable with field measurements. Using the model, N budgets and estimates of all N flows were made. Most of the N input into the ponds (60–70%) accumulated in the bottom detritus of the pond and only 8–10% was converted into fish biomass, of which about half consisted of small fish. Fish production in Fingerponds was limited by turbidity induced light limitation and by nutrient limitation. Reduction of variability of fish production should come from reduced turbidity and sufficient nutrient input to minimize light limitation and maximize fish growth.     

The contribution of diatoms to bioflocs lipid content and the performance of juvenile Litopenaeus vannamei (Boone, 1931) in a BFT culture system

This study aimed to evaluate the contribution of three diatom species on the lipid content of bioflocs, their permanence on the bioflocs and influence on the growth performance of juvenile shrimps. Juveniles of Litopenaeus vannamei were reared (30 days; three replicates per treatment) in biofloc systems inoculated with diatoms Amphora coffeaeformis (A), Cylindrotheca closterium (C), Conticribra weissflogii (W), or biofloc only (BF, chlorophycean rich). Water quality parameters were monitored daily and the microbiota on days 1, 10, 20 and 30. The lipid content and fatty acid profiles of bioflocs were analyzed at the end of the experiment. Shrimp survival rate (99%) at treatment A was significantly higher than at BF. The bioflocs in A treatment presented the highest lipid content, differing significantly from BF and W. The content of EPA (20:5) (n‐3) was significantly higher in A and lower in BF, while linoleic acid (18:2) (n‐6) was significantly higher in BF. The results indicate that high cell density of diatoms can be successfully maintained with silicate addition in biofloc systems and that the pennate A. coffeaeformis and the centric C. weissflogii are potentially better suited than the pennate C. closterium as food supplements for shrimp diets in biofloc nurseries system.     

Dietary protein level and C/N ratio manipulation in zero‐exchange culture of Litopenaeus vannamei: Evaluation of inorganic nitrogen control,biofloc composition and shrimp performance

A 30‐day experiment was conducted to evaluate inorganic nitrogen control, biofloc composition and shrimp performance in zero‐exchange culture tanks for juvenile L. vannamei offered a 35% (P35) or 25% (P25) crude protein feed, each feed supplemented with additional carbohydrate to increase the C/N ratio to 20:1 (CN20) or 15:1 (CN15). Sucrose was used as a carbohydrate to manipulate the two C/N ratios based on the carbon and nitrogen content of both the feeds and sucrose. The four treatments were referred to as: P35 + CN20, P35 + CN15, P25 + CN20 and P25 + CN15. Each treatment consisted of four replicate tanks (125 L), each stocked with 28 shrimp (equivalent to 224 shrimp m^?3). Bioflocs formed and developed based on initial inoculation in all four treatments; and monitored water quality parameters were maintained within acceptable ranges for shrimp culture throughout the experiment. No significant effects (P > 0.05) of dietary protein level, C/N ratio or their interaction were observed on biofloc development (BFV, TSS and BFVI) and inorganic nitrogen (TAN, NO₂^?‐N and NO₃^?‐N) concentrations. At the end of the experiment, proximate analysis of the bioflocs collected from the four treatments showed crude protein levels of 21.3% ~ 32.1%, crude lipid levels of 1.6% ~ 2.8% and ash levels of 43.4% ~ 61.4%. Extracellular protease and amylase activities of the bioflocs were 9.9 ~ 14.4 U g^?1 TSS and 293.5 ~ 403.8 U g^?1 TSS respectively. Biofloc composition and enzyme activity were both affected by dietary protein level (P < 0.01) and C/N ratio (P < 0.05). Survival, per cent weight gain and protein efficiency ratio of shrimp were not affected (P > 0.05) by dietary protein level, C/N ratio or their interaction; however, the feed conversion ratios were significantly lower (P < 0.05) in treatments with high dietary protein (P35) compared with those in treatments with low dietary protein (P25). The results from this study demonstrate that dietary protein level and C/N ratio manipulation can have important implications for water quality, biofloc composition and shrimp performance in intensive, zero‐exchange biofloc‐based culture systems.     

不同C/N对草鱼池生物絮团的形成及水质的影响研究

为了研究草鱼池生物絮团形成所需的适合C/N,实验分析不同C/N水平对水泥池中生物絮团的形成、水质及草鱼生长的影响。对照组投喂基础饲料(C/N为10.8∶1),实验组在基础饲料上添加葡萄糖,控制C/N分别为15∶1、20∶1和25∶1。结果显示,当C/N≥15时,形成的生物絮团可以有效的调节水质,降低水体中的氨氮、亚硝酸盐氮水平;各组的生物絮团体积指数(FVI)随养殖时间逐步增加,在第14天趋于稳定;随着C/N增高,尽管实验组水体中形成的生物絮团粗蛋白含量显著高于对照组(P<0.05),但是草鱼生长却呈下降趋势。综合而言,生物絮团技术应用于草鱼养殖适宜的C/N为15,该比值能促进生物絮团的形成,并能有效降低水中的氨氮、亚硝酸盐氮水平。     

Effects of Pond Volume Manipulation on Production of Fingerling Largemouth Bass,Micropterus salmoides

Hatchery ponds were manipulated by timing of filling to increase the efficiency of production of fingerling largemouth bass, Micropterus salmoides. The effects on pond productivity of fertilizing with chicken manure versus plant meals (consisting of equal parts by weight of cottonseed meal, alfalfa meal, and wheat shorts) were also examined. When ponds were filled in stages, more favorable water temperatures for largemouth bass were achieved, and desirable dissolved oxygen concentrations were maintained. Chlorophyll a levels and plankton community respiration rates were higher in ponds that were fertilized with the plant meals than in ponds fertilized with chicken manure (25% dry matter). Secchi disk visibility was relatively greater in chicken manure ponds than in ponds fertilized with the plant meals; however all differences were not significant. Zooplankton densities were comparable among treatments. Filling ponds in stages had no significant effects on chlorophyll a, plankton community respiration rate, Secchi disk visibility, or zooplankton abundance and population dynamics. Daily production of largemouth bass was greater in ponds filled in stages and fertilized with plant meals than in other treatment ponds. Yield was highest in stage-filled ponds fertilized with plant meals and lowest in full ponds fertilized with chicken manure. Filling ponds in stages reduced the fertilizer cost per kilogram of largemouth bass by 50% in ponds fertilized with plant meals and by 65% in manure-fertilized ponds.     

The Nutrient Profile in Organic Fertilizers

Abstract

In order to manage nitrogen (N) and phosphorous (P) through organic fertilization in aquaculture ponds, it is important to understand the nutrient profile of different animal manures at various concentrations and the respective biological response. The rate of nutrient released from animal manure over time is a key factor in deciding the frequency and quantity of manure required to fertilize ponds. This study was conducted to elucidate the nutrient profile, and its efficiency in terms of primary productivity, of pig, cow, and buffalo manure, at different N:P concentrations in tank. Appropriate concentrations were maintained by using the minimum amount of inorganic fertilizer supplement. This paper also investigated the impact of lime-treated manure, a traditional practice in Vietnam, on primary production (phytoplankton abundance). The average nitrogen (N) and phosphorus (P) content was higher in pig manure (0.54% N and 0.173% P) compared to cow (0.31% N and 0.028% P) and buffalo (0.34% N and 0.013% P). The ammonia release rate increased with increase in N concentration. The average ammonia release rate (all concentrations, 1-2 ppm N) in the pig manure treatment was significantly higher than cow and buffalo manure treatments. Cow and buffalo manures were found to be similar in terms of ammonia release rate. However, soluble phosphorus level was significantly lower in buffalo manure treatments compared with cow manure. The pig manure treatment produced maximum soluble phosphorus levels in the tanks. The primary productivity obtained at various concentrations (1-2 ppm N:0.5 ppm P) did not differ significantly (P > 0.05) in cow and buffalo manure treatments. The primary productivity performance of pig manure was highest amongst the manure types tested. The 1 ppm N:0.5 ppm P concentration from pig manure yielded the maximum average (1.64 mg C/L) net primary productivity. Based on the primary productivity pattern in the tank, which had a significant correlation with nutrient release rate for all manures tested, the frequency of fertilizer application appeared to be most suitable every 8-10 days. However, increasing the frequency of manure application based on the level of nutrient available in the water will provide more control on nutrient and water quality management for pond aquaculture systems. This level of monitoring may not be practical for regional farmers.     

Effect of pig dung on water quality and polyculture of carp species during winter and summer

Theeffect of pig dung, as pond manure [at 18 and 36 tha^–1 yr^–1] and as fish feed ingredient[replacing traditional diet composed of solvent extracted rice bran and mustardcake (1:1) at 25, 50, 75 and 100% levels], was observed on water quality, pondproductivity and survival and growth of carp in polyculture system during winter(12–18 °C) and summer (18–36 °C)months. The studies on water quality parameters viz pH, dissolved oxygen andalkalinity revealed that pig dung even at higher levels (both as manure and /oras feed ingredient) did not deteriorate the quality of water, as all the waterparameters remained within the optimum ranges required for carps. The nutrient(phosphates and nitrates) status of water was significantly better in pondsreceiving pig dung as pond manure at 36 tha^–1 yr^–1. Pond productivity in terms ofplankton production (phyto and zooplankton) was also significantly higher innutrient rich water (36 tha^–1 yr^–1) both during winter andsummer. Further, in all the ponds (including control) phytoplankton levels weresignificantly higher during winter and zooplankton was higher during summer. Thestudies revealed 100% survival of all the fish species in all the treatments.During winter, the growth of carp was higher in treatments where pig dung wasused as feed ingredient (at 25% level), whereas during summer growth was higherwhere pig dung was used either as pond manure and/or as feed ingredient (athigher levels). Further, among carps, the growth of Indian major carps vizCatla catla, Labeo rohita and Cirrhinamrigala was higher during summer and that of exotic carps vizCyprinus carpio and Ctenophayrengodonidella was higher during winter.     

Effects of Feeding Rate on Habitat Quality in Fish Rearing Ponds

Manufactured feeds are commonly added to earthen ponds to enhance growth and survival of juvenile fish. However, excessive feeding may decrease fish production efficiency and yields by causing hypoxia (dissolved oxygen, DO < 2 mg/L) and stimulating excessive phytoplankton, filamentous green algae, and vascular plant growth. In this study, we quantified the effects of manufactured feed addition (no feeding, 1%, or 3% body‐weight/day, BW/d) on DO and inorganic phosphorus (P) and nitrogen (N) concentrations, plant abundance, and invertebrate prey production in ponds stocked with age‐0 channel catfish, Ictalurus punctatus. We found that the 3% BW/d ponds had lower DO concentrations and greater infestation by filamentous green algae (Rhizoclonium spp.) as compared to the 1% BW/d and no‐feeding ponds. Using stable N and carbon (C) isotopes to trace the fate of feed‐derived N and C in ponds, as well as analysis of zooplankton abundance, we determined that the supplied feed did not support or enhance production of natural invertebrate prey. To improve fish production efficiency, we recommend that managers leverage natural prey support of growth during early life, then adjust feeding levels to enhance growth of older fish and maintain suitable habitat quality.     

Bacterial Flora of Artemia Cultured in Earthen Saline Ponds

Aerobic bacteria in pond water, sediments, and Artemia in earthen saline ponds in Saudi Arabia were quantified. Total viable counts (TVC; mean ± SD) in pond water ranged between 7.9 ± 4.8 × 10³ and 1.6 ± 3.7 × 10⁴ colony forming units (cfu)/mL; in sediments between 7.1 ± 4.2 × 10⁶ and 6.5 ± 3.8 × 10⁷ cfu/g; on Artemia surfaces, 3.9 ± 0.9 × 10³ and 1.0 ± 2.9 × 10⁴ cfu/Artemia; and in Artemia homogenate, 4.6 ± 2.4 × 10⁷ and 3.2 ± 3.6 × 10⁸ cfu/g. The bacterial flora was predominantly Gram-negative rods, accounting for 89% of total isolates. Altogether, nine bacterial species of seven genera were identified. Bacteria in pond sediments were the most diverse compared to other populations. In all populations, Vibrio alginolyticus, Vibrio sp., and Staphylococcus sp. were dominant (P < 0.005). The bacterial flora of pond water and sediments were reflected in the bacterial composition on and in Artemia.     

Stable carbon (δ13C) and nitrogen (δ15N) isotopes as natural indicators of live and dry food in Piaractus mesopotamicus (Holmberg, 1887) larval tissue

This study proposed the use of the stable isotope technique to track the type of food utilized by pacu Piaractus mesopotamicus larvae during their development, and to identify the moment when the larvae start using nutrients from the dry diet by retaining its carbon and nitrogen atoms in their body tissues. Five‐day‐old pacu larvae at the onset of exogenous feeding were fed Artemia nauplii or formulated diet exclusively; nauplii+formulated diet during the entire period; or were weaned from nauplii to a dry diet after 3, 6 or 12 days after the first feeding. δ¹³C and δ¹⁵N values for Artemia nauplii were ?15.1‰ and 4.7‰, respectively, and ?25.0‰ and 7.4‰ for the dry diet. The initial isotopic composition of the larval tissue was ?20.2‰ and 9.5‰ for δ¹³C and δ¹⁵N respectively. Later, at the end of a 42‐day feeding period, larvae fed Artemia nauplii alone reached values of ?12.7‰ and 7.0‰ for δ¹³C and δ¹⁵N respectively. Larvae that received the formulated diet alone showed values of ?22.7‰ for δ¹³C and 9.6‰ for δ¹⁵N. The stable isotope technique was precise, and the time at which the larvae utilized Artemia nauplii, and later dry diet as a food source could be clearly defined.     

Increasing cyst yields in Artemia culture ponds in Vietnam: the multi-cycle system

In this study, one-cycle and multi-cycle culture systems for Artemia in seasonal salt ponds are compared. In one-cycle systems, Artemia is inoculated only once per season, while in multicycle systems ponds are drained and re-stocked several times per season. In Vietnam, three-cycle systems gave significantly higher cyst yields than did the one-cycle system. However, after two cycles, systems were not significantly different. Food limitation probably caused the steady decline in cyst yields, as observed in the one-cycle ponds. In these ponds, females have smaller broods (from the second cycle onwards) and during the last cycle the number of adult females is lower than in multi-cycle ponds.