Concrete Ponds Research Articles

Effects of yucca, Yucca schidigera, extract and/or yeast, Saccharomyces cerevisiae, as water additives on growth, biochemical, and antioxidants/oxidant biomarkers of Nile tilapia, Oreochromis niloticus

The current study was carried out to assess the effects of aqueous extract of yucca, Yucca schidigera (YE) and/or yeast, Saccharomyces cerevisiae, used as water additives on the performance of Nile tilapia, Oreochromis niloticus. Fish (28–32 g) were randomly situated in 12 2-m3 concrete ponds at a density of 20 fish per m3 and assigned to four treatments in triplicates where the control ponds were not received any additive (the control) as well as ponds received YE only, yeast only, or both YE + yeast. YE and/or yeast were added daily to ponds water at levels of 1.0 g YE/m3 and/or 1.0 g yeast/m3 for 8 weeks. Neither water temperature nor dissolved oxygen were significantly affected by YE and/or yeast treatment; but pH and NH3 levels were significantly reduced (P < 0.05) by these water additives especially at the YE + yeast treatment. The growth performance of Nile tilapia was significantly improved (P < 0.05) by these water additives and highest growth performance was observed in fish treated with YE + yeast. In contrast, YE and/or yeast treatments did not affect levels of glucose, alanine aminotransferase, and alkaline phosphatase. However, levels of serum total lipids, total protein, albumin, and globulin were higher (P < 0.05) in fish treated with YE + yeast than those observed in the control fish. Adding YE and/or yeast to ponds water significantly decreased levels of aspartate aminotransferase, uric acid, and creatinine (P < 0.05) in fish, especially with the YE + yeast treatment. In addition, significant higher activities of superoxide dismutase, catalase, and glutathione peroxidase, with significant lower malondialdehyde value, were observed in fish treated with YE + yeast (P < 0.05). Overall, these results suggest that using 1.0 g/L of both YE + yeast as water additives improved water quality by reducing pH and ammonia levels, which appears to improve the fish growth and reduce the oxidative stress in Nile tilapia.

Environmental impacts of existing and future aquaculture production: Comparison of technologies and feed options in Singapore

In a context of global population growth and increased food demand, the development of the aquaculture industry has become essential, and aquaculture development policies have flourished. However, aquaculture is associated with various environmental impacts, such as eutrophication or climate change. It is therefore important to assess the environmental sustainability of aquaculture development, for example through the use of life cycle assessment (LCA). Yet, there is limited application of LCA to aquaculture technologies in Asian countries, where most aquaculture growth is taking place, and none of them has assessed environmental impacts of both current and future aquaculture systems. Here, we took Singapore as an example of country, which has recently developed aquaculture development strategies, and we performed a comparative LCA of eight Singaporean aquaculture production systems, thus covering all relevant existing and potential future production technologies. To do so, we built comprehensive life cycle inventories (LCI) of 8 categories of aquaculture production for four species groups in Singapore, for both 2017 and 2040. Two options of feed evolution were assessed in 2040: increasing the part of fishmeal and fish oil (FMFO) produced from trimmings and replacing FMFO by insect-based meal and algal oil. We assessed 11 environmental impact categories, including net primary production use. Overall, per unit of edible seafood produced, the production of marine fishes in sea cages near the shore and in recirculating aquaculture systems were found to be the most attractive options to limit the environmental impacts while increasing seafood production in Singapore. Freshwater fishes produced in concrete ponds were found to have the lowest impact indicator scores per ton of edible seafood produced, but these results were highly sensitive to methodological choices and it was deemed constrained by limited potential to increase its production capacity in the future. Increasing the part of FMFO produced from trimmings is found to have more environmental benefits than insect-based meal. However, the uncertainty concerning the future technologies is high, particularly for anticipating future technologies. Further research is therefore needed to refine the assessment of the potential environmental impacts of future aquaculture production systems, including focusing on novel technologies and new feed options specifically adapted to each country. Meanwhile, we recommend analysts to take inspiration from and build on the detailed LCIs developed in the current study to support assessments of aquaculture systems in other underresearched Asian countries.

Grow-out of transfection and non transfection black tiger shrimp broodstock, Penaeus monodon in concrete pond

Broodstock supply is part of the overall sustainability of tiger shrimp hatchery production. The purpose of this study aimed to evaluate the growth performance and survival rate of broodstock of tiger shrimp transfection and non transfection. This research was conducted at 1000 m2 size of two ponds in Experimental Pond Installation, Research Institute for Coastal Aquaculture, in Punaga Village, Takalar Regency, South Sulawesi. The treatment was different kinds of broodstocks, which were: broodstock candidates of tiger shrimp transfection (A) and non transfection, (B). The 67.9 to 78.9 g/ind of broodstock candidates were stocked 0.2 ind.m−2 and then reared for 90 days. During rearing period, these shrimp were fed using enrichment commercial pelleted feed with content 36-38% of protein in dosage of 10-4%/body weight. Entering the last month of rearing period is given fresh feed were seaworms and squid (3% biomass weight). Feeding frequency was applied in the morning and in the evening. Measured variables were growth, daily growth rate, survival rate and water quality The results showed that the average final weight of transfection and non-transfection black tiger shrimp broodstocks was 80.29 and 92.57 g/ind, respectively. Survival rate of tiger shrimp in this study ranged from 71.5 to 81.5%. The range of water quality during the study still supported the growth and survival rate of black tiger shrimp.

Investigation of the Personal, Social and Economic Factors Influencing Catfish Farmers Utility in Choosing Pond Types: Implications for Profitability

The use of wrong pond types in fish farms has affected profit and this kind of widespread impression could make people quit fish farming if it is not addressed. In this study, investigation of the contributing factors of farmers choice of pond types and profitability in Delta State Nigeria were examined. A multi-stage sampling method was used to carefully choose 180 fish farmers. Data were collected from June to July 2019 using structured questionnaire. The collected data were analyzed by using descriptive statistics, multinomial logit model, regression model and one way Anova. The findings showed that majority of respondents were males and were married. The mean age was 44years with household of 5 people. High proportion of the respondents had secondary education with 9 years’ experience in fish farming. The mean pond size was 148.44m2. Majority of them employed earthen ponds in their fishing business. The major reasons for pond type selection were land availability and scale of production. The result further shows that farmers choice of pond types was influenced by cost of feed, labor cost, pond size, output, stocking density and cost of pond construction. The profit of catfish operators has been positively influenced by education of the respondent, experience of the respondent, stocking capacity, pond size and pond types of the respondent. The average profit realized from earthen pond was N61092.55 while average profit of concrete pond and tarpaulin pond operators are N38394.68 and N29753.19 respectively showing that earthen ponds are more profitable than concrete and tarpaulin ponds. Further results of Anova revealed that at 5% level of probability, there was statistically significant profit difference between the different pond types as a whole. There is need to enhance credit accessibility and to subsidize improved production inputs for effective utilization of pond types.

The effect of using three different levels of Fish Meal on growth criteria and feeding efficiency in Cyprinus Carpio.

Study the effect of three different levels of adding a fishmeal protein concentrate on the growth rates of the common carp fish (Cyprinus carpio) through laboratory experiments, which lasted for 40 days. 27 common carp fish were used with a weight of 2 ± 93.27 g and distributed over 9 concrete ponds with a capacity (300) liters, according to three treatments T1, T2, and T3 distributed in three replicates for each treatment, and put 9 fish (3 fish / repeated). The fish were fed on three different diets, with a protein concentrate ratio of 23%, 15% and 10%, respectively. Measurement of weight, relative specific growth rates and food conversion rates. The best total weight gain increase for the second treatment was recorded (35.478 ± 2.29 g). The best relative growth rates were (37.769 ± 2.51) and specific (0.346 ± 0.02)% g/day and protein efficiency ratio ( 2.365 ± 0.23) for the second treatment also, and significant differences were recorded at (P <0.01) on the two treatments T3; T1 in all the studied characteristics.

Socio-Economic and Environmental Impacts Assessment of Using Different Rainwater Harvesting Techniques in Sarida Catchment, West Bank, Palestine

A statistically representative questionnaire targeted people using rainwater harvesting (RWH) techniques in rural communities of Sarida catchment,West Bank, Palestine was distributed and analyzed. The main objective of this study is to assess the social, economic, and environmental impacts of adopting RWH techniques (e.g. cisterns, concrete and clay ponds, Wadi ponds, earth dams, and stone terraces) in different uses to increase water availability. The results showed a simple sharing of the female component among beneficiaries, while concrete ponds and cisterns were the most used techniques. Actually, social impacts were noticeable by sharing the same RWH structure and reflected to responsibility skills and role exchange increases. On the other hand, RWH techniques showed a significant economic impact for end users represented by enhancing domestic, agricultural,and recreational activities leading to good profit increase. In addition to food security as output, the most important environmental impact was water wasting prevention, which in turn could be linked to sustainable water management and considered as universal challenge for future generations.

Experimental aquatic food chain system: Enhancing Daphnia magna as natural feed using eutrophic waters

An experimental aquatic food chain system was tested to utilize eutrophic water for producing useful natural feed. Water flea (Daphnia magna) was the main focus in this food chain system, in which it was grown on algal biomass bloom in eutrophic water, and harvested following its function as fish feed. The eutrophic waters were originated from a small lake Situ Rawa Kalong and catfish ponds located in Bogor. Daphnia was grown in an aquarium filled with the eutrophic waters from the two localities and reared without artificial feed, with an initial density of 5 individuals/L. The experiment was conducted with three replications for 19 days. Sampling was carried out five times to observe the Daphnia development. The original chlorophyll content in the aquarium of catfish pond and Rawa Kalong water were 257.64 and 211.91 mg/m3, respectively. It was observed that Daphnia consumed algal biomass to support their growth, indicated by the increase of the chlorophyll content in the water was followed by the rise of the Daphnia density to reach a maximum of 245 individuals/L at day 15 for the catfish aquarium, and then overgrazing occurred which resulted in a decrease in the chlorophyll content which was observed from day 12. The density of Daphnia in Rawa Kalong water at day 19 was 152 individuals/L and kept increasing. In the experimentation of Daphnia as natural feed, Daphnia was grown in four concrete ponds and fed with fish pellets. The Daphnia biomass was harvested when it reached a productivity of 1.67 g/m2/day. The feed conversion ratio (FCR) of fish pellets into Daphnia biomass increased with the age of the culture, with the highest value of 0.46 at day 36. Five Bada fish (Rasbora maninjau) per aquarium were then grown for 60 days, fed daily with progressive amount of Daphnia from 1.5 to 4.0 g, and the growth was compared with the control which was fed with an increasing amount of fish pellet. Fish length and weight were observed every 20 days to calculate the growth rate, weight gain, and feed conversion ratio. The results showed that the growth rate of the fish ranged from 0.24–0.98% per day. Fish pellets stimulated a higher growth in the initial phase of growth, but decreased rapidly with the fish age, while Daphnia provided a more stable growth rate. Based on its lower FCR value, Daphnia is more efficient as fish feed. Thus, Daphnia proved to be a suitable natural food source for Rasbora cultivation. Overall, our results indicated that the experimental aquatic food chain system composing of Daphnia as the first level consumer grazing on algal biomass, followed by Rasbora as second-level consumer devouring of Daphnia not only is an efficient and flexible system for reducing the nutrient level in eutrophic waters but also can support a stable growth of cultured fish.

Effect of concrete pond and net-cage culture systems on growth performance and haematological parameters of Siberian sturgeon (Acipenser baerii)

The effect of concrete pond and net-cage culture systems on growth and haematological indices of the Siberian sturgeon (Acipenser baerii) were studied in a 90-day experiment. A total of 300 fish with a stocking density of 12.6 ± 0.37 kg/m2 (initial average weight 1140 ± 53.8 g) were stocked in floating net-cages. Also, 276 fish with a stocking density of 12.6 ± 0.29 kg/m2 and an initial average weight of 1097 ± 72.6 g were stocked in concrete ponds. Throughout the study, the average weight, mean length, and haematological parameters of the fish in each environment were recorded every 30 days. The fish in net-cages displayed higher growth rate (GR), specific growth rate (SGR), and body weight increase (BWI) as well as a lower food conversion rate (FCR) when compared to the fish in concrete ponds. No differences in the condition factor (CF) or survival rate (SR) were found in the trial. In terms of haematological parameters, there was no difference between the ponds and net-cages for the values of red (RBC) and white (WBC) blood cells, haematocrit (Hct), haemoglobin (Hb), MCV, MCH, MCHC, lymphocyte, monocyte, neutrophil, and eosinophil in the initial 30-day and 60-day sampling periods. In the 90-day sampling period, a statistical difference was found in the RBC, MCV, MCH, and WBC values between the ponds and net-cages. Furthermore, in the 90-day sampling period, no statistical difference was found in the Hct, Hb, MCHC, lymphocyte, monocyte, neutrophil, and eosinophil values. Consequently, the Siberian sturgeon culture in net-cages is advantageous to concrete ponds in regards to the growth parameters.

Analysis of Technical Efficiency of Catfish Production in EkitiState of Nigeria

The study investigated the technical efficiency of catfish production in Ekiti State of Nigeria and explored their determinants. Primary data were collected from 120 catfish farmers. Descriptive statistics was used to explain the socioeconomic and the enterprise characteristics of the respondents. The stochastic frontier approach was employed in analyzing the efficiency indices and their determinants. The results showed that Youths that were under 45 years account for majority of the respondents. The study accentuated the important need of women participation in catfish production. All of them attended schools at different levels which should be a boost to managerial abilities of the fish producers. Almostall the farmers (96%) adopted the earthen pond method rather than the concrete pond system because of issues relating to cost. About 89% of them had a stock capacity that ranged between 500 and 1000 fingerlings which stipulated that most of them were small scale operators. Only two of the efficiency correlates were significant. These are stock capacity and quantity oflabour. The return to scale was 0.136 which suggested that catfish farming was still a profitable venture. Fairly high inefficiencies were established in many of the farms and improvement of these was very possible if the fish farmers making up this number adopted the techniques of more efficient farms in the area.

EFECT OF LASERPUNCTURE INDUCTION TO INCREASE GSI AND HSI MALE CATFISH BROODSTOCKS

Induction of laser puncture in the male catfish broodstock has a positive influence by increasing reproductive activity which is very helpful for the process of gonadal maturation. The contribution of laser puncture induction in accelerating gonadal maturation can be seen with an increasing in the value of Gonado Somatic Index (GSI) and Hepato Somatic Idex (HIS) indicators. The purpose of this study was to examine the effect of laser puncture induction on increasing the value of GSI and HIS male catfish broodstock. This experimental study used 48 broodstocks of one year old male catfish with a body weight of 1000-1200 g maintained in a concrete pond. The treatment consisted of 2 groups i.e. without induction and induction of laser puncture, each treatment was repeated 4 times. Laser puncture induction was performed every 15 days at the point of reproduction for 15 seconds until the 75th day. The parameters observed were GSI and HIS. The results showed that there was a highly significant increase (P <0.002) in the value of GSI and HSI in male male catfish broodtock after induced by laser puncture. Conclusion for this research was laser punctur induction at the point of reproduction in male catfish can accelerate gonadal maturation with indicators of increasing GSI and HIS values.

Growth, production and feed conversion performance of the gurami sago (Osphronemus goramy Lacepède, 1801) strain in different aquaculture systems

Background: Giant gourami (Osphronemus goramy, Osphronemidae), belonging to the gurami sago strain, is an important economic fish species that was newly released for domestication in 2018 in Indonesia. The present study aimed to determine the growth, production and feed conversion efficiency of gurami sago strain in different aquaculture systems. Methods: A mean of 240 juveniles were stocked (mean, 54.53 g and 13.88 cm) into concrete ponds, floating net cages and earthen freshwater ponds (12 m3) with three replicates of each. The juveniles were fed a floating commercial pellet diet containing 30% crude protein and 5% crude lipids. Feed was supplied at 3% of fish biomass per day throughout the 90 days of the experiment. The research was conducted in the area surrounding Lake Maninjau of West Sumatera Province, Indonesia. Results: After 90 days, the mean weight of fish reared in concrete ponds was 166.86 g, floating net cages was 179.51 g and earthen freshwater ponds was 149.89 g. The mean final biomass was 37.64 kg for concrete ponds, 41.27 kg for floating net cages, and 33.72 kg for earthen freshwater ponds. The specific growth rates (%/day) for concrete ponds, floating net cages and earthen freshwater ponds were 0.67, 0.75 and 0.62, respectively. The feed conversion rates were 1.45 for concrete ponds, 1.30 for floating net cages and 1.87 for earthen freshwater ponds. The net yields (kg mˉ3) were 2.05 for concrete ponds, 2.27 for floating net cages, and 1.73 for earthen freshwater ponds. The exponents (b) of the length–weight relationship were calculated for concrete ponds (1.0146), floating net cages (1.2641), and earthen freshwater ponds (1.0056). Conclusion: The study showed that the growth performance, production and feed conversion efficiency of the gurami sago strain could be considered a new candidate strain for floating net cage aquaculture in the future.

Growth, production and feed conversion performance of the gurami sago (Osphronemus goramy Lacepède, 1801) strain in different aquaculture systems

Background: Giant gourami ( Osphronemus goramy, Osphronemidae), belonging to gurami sago strain, is an important economic fish species that was newly released for domestication in 2018 in Indonesia. The present study aimed to determine the growth, production and feed conversion efficiency of gurami sago strain in different aquaculture systems. Methods: A mean of 240 juveniles were stocked (initial weight mean, 54.53 g and length 13.88 cm) into concrete ponds, floating net cages and earthen freshwater ponds (12 m 3) with three replicates of each. The juveniles were fed a floating commercial pellet diet containing 30% crude protein and 5% crude lipids. Feed was supplied at 3% of fish biomass per day throughout the 90 days of the experiment. The research was conducted in the area surrounding Lake Maninjau of Indonesia. Results: After 90 days, the mean weight of fish reared in concrete ponds was 166.86 g, floating net cages was 179.51 g and earthen freshwater ponds was 149.89 g. The mean final biomass was 37.64 kg for concrete ponds, 41.27 kg for floating net cages, and 33.72 kg for earthen freshwater ponds. The specific growth rates (%/day) for concrete ponds, floating net cages and earthen freshwater ponds were 0.67, 0.75 and 0.62, respectively. The feed conversion rates were 1.45 for concrete ponds, 1.30 for floating net cages and 1.87 for earthen freshwater ponds. The net yields (kg m ˉ3) were 2.05 for concrete ponds, 2.27 for floating net cages, and 1.73 for earthen freshwater ponds. The exponents (b) of the length–weight relationship were calculated for concrete ponds (1.0146), floating net cages (1.2641), and earthen freshwater ponds (1.0056). Conclusion: The study showed that the growth performance, production and feed conversion efficiency of the gurami sago strain were the best found in floating net cages and considered a new aquaculture system in the future.

Effects of Creatine and Guanidinoacetic Acid as Feed Additives on Nile Tilapia (Oreochromis niloticus) Growth Performance

This study was designed to investigate the effect of Creatine (Cr) and Guanidinoacetic acid (GAA) as feed additives on growth performance, feed utilization and body composition of sex reversed (male) Nile tilapia (Oreochromis niloticus) fingerlings. Creatine and Guanidinoacetic acid play an important role in metabolism and can be applied in aquaculture for improving the growth performance, feed utilization and carcass composition of aquatic animals.Nile tilapia (10.4±0.4 g / fish) were fed a commercial diet (30% crude proteinand gross energy 4120.7 Kcal/kg.) supplemented with different additives of Cr and GAA (0.8 and1.2g / kg diet). Fish were randomly distributed (in triplicates) into 5 treatments (control, Cr 0.8, Cr 1.2, GAA 0.8 and GAA 1.2 g/ kg diet). Treatments were performed in 15 concrete ponds (1x4 m each). Fish were fed three times a day for 12 weeks at 4% of their body weight. The optimum growth performance, feed utilization and body composition were obtained at 1.2g GAA/ kg diet. The GAA in Nile tilapia diet was promising for enhancing the growth performance in Nile tilapia which may improve fish production. Using GAA is beneficial in aquaculture, definitely on Nile tilapia farming.

Rice intercropping with alligator flag (Thalia dealbata): A novel model to produce safe cereal grains while remediating cadmium contaminated paddy soil

Phytoremediation has been employed as a cost-effective technique to remove the cadmium (Cd) from soil and water in several ecosystems. However, little is known about whether intercropping the remediating plants with rice (Oryza sativa) crop could reduce Cd accumulation in rice grains. We conducted greenhouse pot and concrete pond trials to explore the effects of intercropping alligator flag (Thalia dealbata, Marantaceae) on soil Cd remediation, paddy soil and microbial properties, and rice production. Our results suggest that intercropping with alligator flag significantly decreased Cd absorption, transportation, and accumulation from the soil to the rice grains (under 0.2 mg kg–1 at a soil Cd content below 2.50 mg kg–1). This decrease was due to the lowered Cd availability and higher soil pH in the rice-alligator flag intercropping system. Although planting alligator flag resulted in the reduction of soil NH4-N and NO3-N, Cd content in the rhizosphere was the main factor restricting microbial biomass, species, and community composition. Alligator flag could tolerate higher Cd contamination, and accumulate and stabilize more Cd in its tissues than rice. Our study suggests that alligator flag intercropped with rice has potential as a phytostabilization plant to produce rice safely for human consumption in moderately Cd-contaminated soils.

Growth, production and feed conversion performance of the gurami sago (Osphronemus goramy Lacepède, 1801) strain in different aquaculture systems

Background: Giant gourami (Osphronemus goramy, Osphronemidae), belonging to the gurami sago strain, is an important economic fish species that was newly released for domestication in 2018 in Indonesia. The present study aimed to determine the growth, production and feed conversion efficiency of gurami sago strain in different aquaculture systems. Methods: A mean of 240 juveniles were stocked (mean, 54.53 g and 13.88 cm) into concrete ponds, floating net cages and earthen freshwater ponds (12 m3) with three replicates of each. The juveniles were fed a floating commercial pellet diet containing 30% crude protein and 5% crude lipids. Feed was supplied at 3% of fish biomass per day throughout the 90 days of the experiment. The research was conducted in the area surrounding Lake Maninjau of West Sumatera Province, Indonesia. Results: After 90 days, the mean weight of fish reared in concrete ponds was 166.86 g, floating net cages was 179.51 g and earthen freshwater ponds was 149.89 g. The mean final biomass was 37.64 kg for concrete ponds, 41.27 kg for floating net cages, and 33.72 kg for earthen freshwater ponds. The specific growth rates (%/day) for concrete ponds, floating net cages and earthen freshwater ponds were 0.67, 0.75 and 0.62, respectively. The feed conversion rates were 1.45 for concrete ponds, 1.30 for floating net cages and 1.87 for earthen freshwater ponds. The net yields (kg mˉ3) were 2.05 for concrete ponds, 2.27 for floating net cages, and 1.73 for earthen freshwater ponds. The exponents (b) of the length–weight relationship were calculated for concrete ponds (1.0146), floating net cages (1.2641), and earthen freshwater ponds (1.0056). Conclusion: The study showed that the growth performance, production and feed conversion efficiency of the gurami sago strain could be considered a new candidate strain for floating net cage aquaculture in the future.

Evaluating the influence of different water sources on water quality, survival and growth rates of Nile tilapia (Oreochomis niloticus) larvae in tilapia hatcheries

This study was conducted to evaluate the effect of different water sources on survival rate and growth performance of Nile tilapia (O. niloticus) larvae during nursing period. Larvae (post yolk sac stage) were stocked at 50000 / pond and fed 48 % crude protein diet 6 times daily at rates of 35, 26 and 18% of their weight in the successive three weeks, respectively. Nine concrete ponds assigned for 3 treatments, triplicates in each. The ground water and agricultural drainage water were the water sources in the first and third treatments, respectively, while the second treatment received a 1: 1 mixture of the two water sources. Water samples, for some physico-chemical analysis, were monitored before pumping water into the ponds and within the ponds at each fry harvest. The experiment lasted for 21 days and replicated four times. At the end of each rearing period, fry number was estimated in each pond; the survival and growth rates were calculated. The results showed that the significantly highest survival and growth rates were obtained in the mixed water treatment. Mixing agricultural drainage water with ground water results the most suitable water quality for Nile tilapia performance than each of these sources separately. Generally, water quality parameters for the studied sources at the end of each rearing period were within the acceptable range for fish culture.

Inventory of ectoparasites in pacific white shrimp (Litopenaeus vannamei) that cultivated with high density

Ectoparasites can attack on pacific white shrimp (Litopenaeus vannamei) which are kept in high density concrete ponds. The purpose of this study was to determine the type, prevalence, infestation and intensity degree of ectoparasites pacific white shrimp Postlarva (PL11 – PL15) stage and Postlarva (PL20 - PL30) stage in Bangil ponds that are cultivated with high density. The method used in this research is a survey method with random sampling. Data were analyzed using T test. The results of this study indicate that there are three genus of ectoparasites both in the pacific white shrimp PL11 - PL15 stage and PL20 - PL30 stage, namely Zoothamnium sp., Vorticella sp. and Epistylis sp. The prevalence of ectoparasites in pacific white shrimp is in the PL20 - PL30 stage at 100% while the prevalence of ectoparasites in the PL11 - PL15 stage is 75%. The level of ectoparasite intensity that attacks the pacific white shrimp (PL11 - PL15) includes a moderate category of 21.8 individuals/head, while the level of intensity of ectoparasites that attacks the pacific white shrimp (PL20 - PL30) includes a very severe category that is 814.05 individuals/head.

Effects of food, salinity, and ammonia-nitrogen on the physiology of juvenile seahorse (Hippocampus erectus) in two typical culture models in China

Food and water environments are key factors affecting juvenile survival rate in seahorse aquaculture. In order to adjust to local conditions, different seahorse (Hippocampus erectus) breeding models were developed in North and South China. Seahorses in North China were commonly fed Artemia in indoor containers with a stable water environment, while most seahorses in South China were fed copepods in outdoor concrete ponds. Firstly, we compared the effect of food type on juvenile seahorses based on a one-month feeding experiment and found no significant difference in body length. However, the insulin-like growth factor 1 (IGF-1) gene expression was significantly higher in the liver of seahorses fed copepods than in the lever of seahorses fed Artemia, suggesting that copepods promoted better growth. A high expression of stress-related genes, namely, heat shock proteins 70 (HSP70) and Mn superoxide dismutase (Mn-SOD), in the liver of the seahorses that were fed copepods suggested that copepods might cause more stress on juveniles. Lower leptin gene expression in the liver of seahorses fed Artemia than in those fed copepods proved that Artemia was better for satiating the juveniles. Furthermore, the potential effects of salinity (15 and 30 ppt) and ammonia‑nitrogen (0, 5, and 15 mg/L) on juvenile seahorse physiological stress were studied through a 5-d orthogonal experiment. Both lower salinity and higher ammonia‑nitrogen increased the ventilation rate significantly. Low salinity caused a rapid increase in the ventilation rate on day 1, while high ammonia‑nitrogen was the main factor during the later period (days 2–5). Significant changes in the mRNA expression of genes, including Na+: K+:2Cl− cotransporter 1 (NKCC1) and Na, K-ATPase (NKA) in the gill, HSP70, Mn-SOD, glutamate dehydrogenase (GDH), and glutamyl synthase (GS) in the liver, indicated that seahorses are sensitive to acute salinity decline. In addition, high ammonia‑nitrogen exposure significantly changed the expression of genes (i.e., Mn-SOD, GDH, and GS) in seahorses exposed to low salinity level, while no significant variation was observed in seahorses exposed to normal salinity, suggesting that salinity decline might increase the negative effects of ammonia‑nitrogen stress. The present study provides a better understanding of how food, salinity, and ammonia‑nitrogen affect juvenile seahorses, and will be potentially important to improve animal welfare and increase production efficiency.

Growth Performance of Nile Tilapia (Oreochromis Niloticus) Fingerlings Fed on Soybean (Glycine Max) Compared to Dagaa (Rastreneobola Argentea) Meal with Diet Supplement of Maize Bran.

A study was conducted at Maseno University to evaluate the growth performance of Nile tilapia (Oreochromis niloticus) fingerlings fed on soybean (Glycine max) and dagaa (Rastrineobola argentea) meals separately. The experimental feeds used were Glycine max and Rastrineobola argentea. A total of 160 fingerlings were used during this experiment. The fingerlings were fed at 5% of their mean body weight on daily basis for 5 weeks and the feed amount adjusted after every sapling in relation to body weight. There were 2 replicates for each feed therefore 4 hapas were used hence 40 fingerlings for each hapa net. The concrete pond used was drained and left to dry for 4 days to kill any available parasites before filling with water. After filling the pond with water, it was fertilized using DAP to promote the growth of phytoplankton in the water before stocking with the fingerlings. Sampling was done weekly to determine SGR and FCR of the fingerlings from each hapa. Statistical analysis was done using SPSS v. 16.02. Although there was observable difference, statistically there was no significant difference between the two treatments. In weight p=0.73 (p>0.05) and length p=0.61 (p>0.05). The average temperature during the project period was 24.4°C+/- 0.33 while the pH was 8.87+/- 0.28.

Microbial Communities of Culture Water and African Catfish Reared in Different Aquaculture Systems in Nigeria Analyzed Using Culture Dependent Techniques

The microbial communities of culture water and catfish C. gariepinus from three replicates of earthen, concrete and tarpaulin ponds in Nigeria were analyzed. Waters was collected from 25 cm below pond water surface per culture system. Three catfish per replicate system were also collected and analyzed in the lab. Catfish gut, skin and gills were analyzed. Earthen ponds had significantly more diverse microbial community and coliform forming units (CFU/ml) 2.43 x10-4 CFU/ml than the rest systems. Earthen ponds had consortium of Klebsiella pneumonia, S. aureus and Salmonella enteritidis and E. coli, which was more diverse than all other aquaculture systems. Microbiota of tarpaulin ponds was 2.10x10-4 /ml CFU and this was significantly (P&lt;0.05) higher than concrete ponds (1.50x10-4 CFU/ml). Tarpaulin ponds had K. pneumoniae and E. coli, while concrete pond had S. aureus and S. enteritidis. Biofilm formation could have lead to colonization of the fish body part. The skin and gills had similar microbiota as the culture water compared to the gut. The gut microbial communities were not synonymous with the culture water.