Specific Growth Rate Values Research Articles

Phycoremediation of pollutants from secondary treated coke-oven wastewater using poultry litter as nutrient source: a cost-effective polishing technique.

This article focuses on the phycoremediation of pollutants from secondary treated coke-oven effluent through a green and economical route. A microalgal sample was collected and identified as a consortium of Chlorella sp. and Synechococcus sp. The culture cost was reduced by using poultry litter extract as supplementary material to BG-11 medium. Since the major pollutants present in real secondary treated coke-oven wastewater are phenol, ammoniacal-N (NH4+) and cyanide, several matrices were designed with these three major pollutants by varying their initial concentrations such as phenol (2-10 mg/L), cyanide (0.3-1 mg/L) and NH4+ (100-200 mg/L), termed as simulated secondary treated coke-oven wastewater. Maximum removal was observed with individual solutions of phenol (4 mg/L), cyanide (0.6 mg/L) and NH4+ (175 mg/L), while maximum removal in simulated secondary treated coke-oven wastewater was observed at higher concentrations of phenol (8 mg/L) and cyanide (0.8 mg/L) and the same concentration of NH4+ (175 mg/L). A consortium was found effective to meet statutory limits of pollutants. Kinetic model was developed for predicting growth of consortium and observed that the poultry litter extract-enriched BG-11 medium showed higher values of maximum specific growth rate (0.56 per day) and carrying capacity (1,330 mg/L) than that in BG-11 medium only.

Co-culture of Indian white shrimp, Penaeus indicus and seaweed, Gracilaria tenuistipitata in amended biofloc and recirculating aquaculture system (RAS)

A 60 days nursery-based co-culture of Indian white shrimp, Penaeus indicus along with seaweed, Gracilaria tenuistipitata trial was carried out in Recirculatory Aquaculture System (RAS) of 6000 Liters capacity tank (FRP, reinforced fibre plastics) by using biofloc technology (BFT) to evaluate the growth, survival performance and immune potential. Accordingly a completely randomized experiment was designed with six treatments. These treatments were: T1- Static system (Control), T2 - RAS with BFT, T3 - RAS with Gracilaria, T4 - RAS and BFT customized with bacterial consortium, T5 - RAS with BFT + Gracilaria + bacterial consortium, T6 - Static + Gracilaria + BFT (without consortium and without RAS). Shrimp post larvae (0.08 ± 0.03 g) were stocked at a density of 3000 nos./ton. RAS with BFT along with the seaweed and bacterial consortium showed significantly higher growth and survival compared to control (T1) and treatments without BFT (T3). The control (T1) exhibited significantly lower growth, weight gain, specific growth rate, yield and higher FCR value than that of the RAS + BFT (T2), RAS+ seaweed (T3) and RAS + BFT or their combinations with bacterial consortium (T4 and T5). The treatment having seaweed without BFT (T3) showed higher survival than the static control (T1), but no significant difference in growth. The highest ABW of 4.23 ± 0.39 was obtained in T4 (BFT customized with consortium) followed by T5 (BFT + seaweed + bacterial consortium) and lowest was observed in T1 (2.14 ± 0.4). Similarly, the highest survival (92.33 ± 1.52) and production (10.39 ± 0.24 kg/ton) was observed in T5. Significantly higher NH4-N and NO2-N was accumulated in the control (T1) in comparison with other treatment like T4 and T5. Immune parameters viz., PPO activity, Total Serum Protein and Total Hemocyte Count (THC) showed significantly higher values in all the treatments compared to control. This study establishes the novel concept of incorporation of macroalgae in biofloc based RAS improving the production performance and immune response of shrimp during nursery as well as grow-out phase.

Addition of Bamboo Charcoal to Selenium (Se)-Rich Feed Improves Growth and Antioxidant Capacity of Blunt Snout Bream (Megalobrama amblycephala).

Simple SummaryIn our previous studies, we determined that juvenile blunt snout bream (Megalobrama amblycephala) require a selenium (Se) dietary intake of 0.958–0.959 mg/kg based on the quadratic fitting method. Nevertheless, growth rates were significantly affected, and the expression of anti-inflammatory factors was inhibited when the feed contained excessively high Se concentrations. Given its activity as an insoluble carrier, bamboo charcoal can be used as a dietary supplement in fish feed to absorb and slowly release excess nutrients. However, these hypotheses have not been evaluated in diets containing excess Se. The present study determined that 2–3 g/kg bamboo charcoal inclusion in Se-rich feed could improve the growth performance of blunt snout bream. Dietary bamboo charcoal supplementation mobilized the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 signaling while suppressing NF-κB signaling.The ability of bamboo charcoal to reduce the negative effects of high dietary selenium (Se) concentrations was assessed by feeding juvenile blunt snout bream (Megalobrama amblycephala) one of five Se-rich diets (1.5 mg/kg Se; 36% protein, 8.7% lipid) containing graded levels (0–4 g/kg) of bamboo charcoal powder for eight weeks. There were four tanks (350 L) of fish (initial weight 16.0 ± 0.5 g) for each treatment, and the fish were fed to satiation four times each day. At the end of the feeding trial, all of the fish from each tank were weighed to calculate the growth performance. Blood samples were firstly obtained to collect plasma for the biochemical indexes determination. Liver tissues were then collected to determine the antioxidant enzyme activities and gene expression. Dorsal muscles were also collected to determine the nutrient composition. The results show that when the bamboo charcoal content in the Se-rich feed ranged between 0 and 3 g/kg, the weight growth rate (WGR) and specific growth rate (SGR) values increased with the higher dietary bamboo charcoal content, and the maximum WGR and SGR values were achieved when the bamboo charcoal content in the Se-rich feed was 2–3 g/kg (p < 0.05). The Se content in muscle tissues decreased significantly with the increased bamboo charcoal content (p < 0.05) in the Se-rich feed, which ranged from 0 to 4 g/kg. When the bamboo charcoal content in the Se-rich feed was 2–3 g/kg, the levels of glucose (GLU) and albumin (ALB) in plasma reached a maximum (p < 0.05), whereas the level of alkaline phosphatase (ALP) reached a minimum (p < 0.05). Additionally, the activities of catalase (CAT), total superoxide dismutase (T-SOD), total antioxidative capacity (T-AOC), and glutathione peroxidase (GSH-Px) were significantly enhanced (p < 0.05) when the bamboo charcoal content was 3 g/kg. In contrast, the malondialdehyde (MDA) level increased sharply when the bamboo charcoal content in the Se-rich feed was 1 g/kg, compared to the control group and the groups supplemented with 2–3 g/kg bamboo charcoal (p < 0.05). Regarding mRNA-level gene expression, the results show that dietary supplementation with 0 to 3 g/kg of bamboo charcoal increased the expression of keap1 and nrf2, whereas nfkb expression was inhibited (p < 0.05). The mRNA expression of the antioxidant enzymes cat, gpx, and mn-sod was consistently enhanced in the group fed with the 3 g/kg bamboo charcoal diet (p < 0.05). The expression of the pro-inflammatory cytokines tnfα and tgfβ was inhibited in the groups supplemented with 2–3 g/kg bamboo charcoal, whereas the expression of anti-inflammatory cytokines (il10) increased in the bamboo charcoal supplementation groups compared to the control group (p < 0.05). Generally, supplementation with 2–3 g/kg of bamboo charcoal in Se-rich feed improved the growth performance, physiological status, and antioxidant enzyme activities of blunt snout bream. Moreover, bamboo charcoal supplementation in Se-rich diets stimulated the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 and suppressing NF-κB.

Effects of hypoxia and hyperoxia on growth parameters and transcription levels of growth, immune system and stress related genes in rainbow trout

Hypoxia and hyperoxia are disparate stressors which can have destructive influences on fish growth and physiology. It is yet to be determined if hypoxia and hyperoxia have a cumulative effect in aquatic ecosystems that affect biological parameters in fish, and to understand if this is associated with gene expression. Here we address whether growth performance and expressions of growth, immune system and stress related genes were affected by hypoxia and hyperoxia in fish. Rainbow trout was chosen as the study organism due to its excellent service as biomonitor. After an acclimatization period, fish were exposed to hypoxia (4.0 ± 0.5 ppm O2), normoxia (7.5 ± 0.5 ppm O2) and hyperoxia (12 ± 1.2 ppm O2) for 28 days. At 6 h, 12 h, 24 h, 48 h, 72 h and 28 days, samples were collected. Hypoxia and hyperoxia negatively affected weight gain (WG), specific growth rate (SGR), survival rate (SR) and feed conversion ratio (FCR). The best WG, SGR, SR and FCR values occurred in fish exposed to normoxia, whereas hypoxia was most suppressive on growth and hyperoxia showed intermediate suppression of these parameters. Gene expression analyses were performed in liver and results revealed that long term exposure caused reduced growth hormone-I (GH-I) and insulin like growth factor I-II (IGF I-II) levels in both hypoxia and hyperoxia-treated fish. Heat shock protein (HSP70) levels increased in both hypoxia and hyperoxia treatment, and both exposures caused elevation of leptin (LEP) expression in long-term exposure. Overall data indicate that both hypoxia and hyperoxia cause stress in rainbow trout and negatively affects growth parameters.

Marine Algal Sensitivity to Source and Weathered Oils.

After the Deepwater Horizon oil spill in 2010, toxicity tests were conducted using 4 microalgae (Dunaliella tertiolecta, Skeletonema costatum, Isochrysis galbana, and Thalassiosira pseudonana) and one macroalga (Ectocarpus siliculosus) to study potential impacts on phytoplankton and other primary producers in the Gulf of Mexico and characterize species sensitivity. Tests were performed with Corexit 9500 and fresh source oil and weathered oil samples collected from the field during the Deepwater Horizon oil spill. Because crude oils are mixtures of poorly water-soluble hydrocarbons, dosing was performed using water-accommodated fractions (WAFs) and chemically enhanced (CE) WAFs with the addition of dispersant at a 1:20 dispersant:oil ratio using standard toxicity testing protocols. Exposure media were analyzed for volatile organic compounds, parent and alkylated polycyclic aromatic hydrocarbons, and saturated hydrocarbon compounds. Toxicity was reported as no-observable effect concentration and median effect concentration (EC50) values for average specific growth rate based on nominal percent dilution of stock solution WAFs and sum of dissolved oil toxic units for WAF/CEWAF tests. The macroalga and green alga D. tertiolecta were largely unaffected by any WAF or CEWAFs tested. Isochrysis galbana was found to be the most sensitive species overall with significant growth rate inhibitions for dispersant and all the WAFs/CEWAFs tested. Physically dispersed source oils were generally more toxic than weathered oils. The protectiveness of the chronic toxic units was effective at identifying observed algal growth rate inhibitions across algal species and oil types despite the impact of dispersants. Environ Toxicol Chem 2021;40:2742-2754. © 2021 SETAC.

Effects of taurine supplementation in a high-carbohydrate diet on growth performance, plasma biochemical, digestive and glucose metabolism enzymes in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus)

This study conducted an 8-week feeding trial to evaluate the effects of taurine supplementation in a high-carbohydrate diet on the growth performance, plasma biochemical indexes and glucose metabolism of hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus). Six iso-nitrogenous (45.94 %) and iso-lipidic (8.71 %) diets were formulated containing 20 % carbohydrates (positive control group, PC) and 30 % carbohydrates (negative control group, NC), and were supplemented with 0.4 % (T1), 0.8 % (T2), 1.2 % (T3) of 1.6 % (T4) taurine on the basis of the PC diet. Five hundred forty fish (initial body weight 12.10 ± 0.30 g) were randomly distributed among the six treatments with triplicate groups of 30 fish in each treatment. The results showed that, compared with the PC, fish fed the NC diet significantly decreased the weight gain rate (WGR) and specific growth rate (SGR), the level of insulin-like growth factor-1 receptor (IGF-1R) in the liver, the activities of trypsin and α-amylase (AMS) in the intestine, and the activity of glucokinase (GK) in the liver. Under taurine supplementation, the highest significant values of WGR and SGR were found at the T3. The optimal taurine requirements in the 30 % carbohydrate diet were found to be 1.31 %, 1.31 % and 1.05 % based on WGR, SGR and feed coefficient rate (FCR), respectively. Compared with the NC, significantly higher activities of intestinal trypsin and AMS were found in the T1-T4. Hybrid grouper fed the T3 diet showed the significantly highest levels of plasma insulin and triglycerides. Significant increase in GK activity in the liver occurred under taurine supplementation above 0.8 %. Hepatocyte oil-red O and hematoxylin-eosin staining showed that 0.4 %∼1.2 % taurine supplementation could release hepatocyte fat deposition and maintain hepatocyte structure. Therefore, taurine enhances intestinal digestive function and regulates glycolipid metabolic to improve the utilization of dietary carbohydrates, thus promoting the growth of hybrid grouper.

Dietary Pure Polyhydroxyalkanoate Effects on Growth, Nutrient Utilization, Apparent Digestibility, and Hematology in Nile Tilapia

AbstractIn the past decade, different groups of additives (probiotics, oligosaccharides, and plant extracts) have been widely researched and used in worldwide aquaculture. Recently, other groups, such as biopolymers (e.g., poly‐β‐hydroxybutyrate) with prebiotic properties, have been investigated. Among biopolymers, the use of pure polyhydroxyalkanoate (PHA; composition = 95–100%) as a feed additive in aquaculture has not been studied yet. Therefore, the aim of the present study was to research the effects of four supplementation levels of pure PHA on growth, survival, feed and nutrient utilization, apparent digestibility coefficients (ADCs), and hematology of Nile Tilapia Oreochromis niloticus. Five isonitrogenous and isolipidic diets were designed, including a control (C) diet without PHA supplementation. Remaining diets were supplemented with the following levels of PHA: PHA 0.1% (basal diet + 0.1% PHA), PHA 0.5% (basal diet + 0.5% PHA), PHA 1.0% (basal diet + 1.0% PHA), and PHA 2.0% (basal diet + 2.0% PHA). After a 70‐d feeding test period, the PHA 0.5% and PHA 1.0% experimental groups showed significantly higher final body weight, weight gain, specific growth rate, lipid efficiency and productive value, and ADCs of lipid and energy compared to those of the C group. Protein efficiency ratio was significantly higher in fish fed the PHA 0.1%, PHA 0.5%, and PHA 1.0% diets compared to the C group. Protein productive value significantly increased in the PHA 1.0% group. The ADC of protein was significantly higher in fish fed diets supplemented with any level of PHA compared to C fish. Regarding hematological parameters, hematocrit value showed a significant increase in fish fed PHA 0.1% compared to the C group. Leukocyte composition (%) did not show significant differences among experimental groups. Based on polynomial regression analysis, the optimum inclusion levels of PHA in Nile Tilapia diets were 0.82–0.92% for growth performance, 1.0–1.1% for nutrient utilization, 1.0–1.2% for ADCs, and 1.34% for hematocrit. Cost–benefit ratio analysis revealed nonsignificant but numerical differences among experimental diets. Results suggest that pure PHA, when supplemented at 0.1, 0.5, 1.0, or 2.0%, has certain positive effects on growth, nutrient and feed utilization, and ADCs without compromising Nile Tilapia hematology or health.

Dietary effect of moringa (Moringa oleifera; Lamarck, 1785) leaf powder on growth response of tilapia (Oreochromis niloticus; Linnaeus, 1758)

Management of fish health is one of the main considerations in aquaculture and different plant compounds are being used for supporting fish health to minimize the negative impacts of synthetic aqua drugs. In the present experiment, potentiality of moringa (Moringa oleifera; Lamarck, 1785) leaf as a nutritious dietary source for tilapia (Oreochromis niloticus; Linnaeus, 1758) fish was tested and the duration was two months from 30th September to 30th November, 2020. The moringa leaves were brought, cleaned, dried, and finally crushed into powder. Three experimental diets were formulated using the processed moringa leaf powder (MLP) at the rate of 0% (MLP0%) as control, 10% (MLP10%) and 20% (MLP20%) as treatment mixing with rice bran, wheat bran, mustard oil cake, fish meal, soya oil and vitamin-mineral premix. Fifteen tilapia fingerlings having average initial length 10.88±0.11 cm and initial weight 29.06±0.50 g was stocked in each tank with 90 L water. Sixty days feeding trial was performed with three replications of each treatment. The fishes were fed with formulated feeds twice daily at 9 am and 4 pm at a rate of 3% of their body mass. Sampling of fish and water quality parameters were carried out at twelve days interval. Moreover, the blood glucose and cholesterol of tilapia were measured monthly. Final length, final weight, weight gain, percent weight gain, feed conversion ratio (FCR), specific growth rate (SGR) and production of tilapia were significantly different among the treatments. The highest FCR (3.17±0.25) and SGR (1.33±0.12 %) values were in MLP20% and MLP10%, respectively. In the experiment, the highest and the lowest tilapia production were 9.21±0.39 and 7.39±0.35 kg m-3 in MLP10% and MLP20%, respectively. The blood glucose values were significantly different among the treatments (p&lt; 0.05) and the highest value was in MLP0% (48.00±2.00 mg dl-1). Moreover, the highest and the lowest blood cholesterol was found in MLP0% (177.67±2.52 mg dl-1) and MLP20% (148.33±1.53 mg dl-1), respectively whereas the values were highly significantly different among the treatments (p≤ 0.01). Water quality parameters were statistically similar among the treatments (p&gt; 0.05) and the values were within acceptable range for tilapia culture. Asian J. Med. Biol. Res. 2021, 7 (2), 153-163

Antioxidant and immune response of juvenile red tilapia (Oreochromis sp) cultured at different densities in sea water with biofloc plus probiotics

Scarce information is available about the benefits of adding probiotics to biofloc systems on the growth and health status of red tilapia reared in seawater. This study aimed to assess the growth performance, antioxidant and immune responses of red tilapia (Oreochromis sp.) reared in seawater with two stocking densities (D1, 120 fish/m3; D2, 240 fish/m3) with biofloc plus probiotics. For each density, juvenile red tilapia (6.7 ± 0.2 g) were cultured under three different experimental conditions: clear seawater (control group, C), seawater enriched with biofloc (B), and seawater enriched with biofloc plus probiotics (BP). The bioassay lasted 7 weeks. Fish reared in D2 showed the lowest specific growth rate value, protein efficiency ratio (PER), and superoxide dismutase (SOD) and catalase (CAT) activity but the highest feed conversion ratio (FCR) and viscerosomatic index (VSI). However, fish from BPD2 showed FCR and PER values similar to those of fish in D1. Fish from the control group showed the highest globulin concentration (GB) with the lowest albumin:globulin ratio (AL:GB), in contrast to fish from BPD2, which also showed the highest glutathione peroxidase (GPX) activities. In conclusion, a high culture density affects the growth performance of red tilapia regardless of biofloc and probiotics in the system; however, supplying biofloc plus probiotics into the cultures improves the feed efficiency as well as immune and antioxidant responses of hybrid red tilapia when reared at high densities in seawater.

Effect of temperature rise on growth performance, feed intake, feed conversion ratio and sex ratio of the Nile Tilapia, Oreochromis niloticus

This study was conducted to investigate the effect of increasing water temperature on growth performance, feed intake, feed conversion ratio, and sex ratio of Oreochromis niloticus. Two groups of O. niloticus fries (3 days post-hatching) were reared in an indoor system, at 30°C and 34°C. In the second group, the water temperature was increased to 36°C for only four hours a day, for the first 25 days of the experiment. At the end of the experiment, the values of body weight, length, specific and daily growth rates, and feed intake were comparable but slightly higher at 30°C. The feed conversion ratio was better in the control tank (30°C) than in the experimental one (36°C). Condition factor was higher than 1 at both temperatures indicating the general well-being of fries along the study period. The sex was skewed towards males under the effect of high temperature (36°C) in the experimental tank.

Effect of biofloc system at different salinities and crude protein levels on water quality, growth performance, and survival rate of flathead grey mullet (Mugil cephalus).

The present trial was conducted to study the effects of C/N ratio to biofloc technology (BFT) at different salinities on water quality, growth performance, and economic feasibility of flathead grey mullet fingerling. BFT was in natural light (12:12h light: dark schedule) with concrete tanks (size 6m3 water), filled with underground marine and tab water, representing three salinities (fresh, brackish 15.5ppt, and saline 33ppt). Diets contain crude protein (20%, 24%) were applied under the biofloc system, two levels of C/N ratio through adding 60% starch of the produced daily diet. Two biofloc treatments under different salinity were managed. BFT ponds were aerated and agitated using an air blower. Forty-two fingerlings with an initial body weight of 10.89 ±0.12 g/fish of grey mullet were stocked in each pond. Feed was applied daily at 3% of the total fish biomass in each pond. Survival rates of the mullet were above 91%, with a significant (P≤0.05) difference for the brackish water with both (20%, 24% CP). Regarding growth performances of the grey mullet at the three salinities with 60% starch, the highest final body weight (FBW), weight gain (WG), and specific growth rate (SGR) values were recorded for fish reared in fresh and brackish water, respectively with no significant differences due to salinities or diets. Water quality parameters alternated between safe values except for nitrate, and no significant (P>0.05) difference was recorded for zooplankton counts. No significant effects of salinity on the mullet growth were recorded under BFT.

Water temperature effects on growth performance, proximate body and tissue composition, morphometric characteristics and gastrointestinal evacuation processes of juvenile meagre, Argyrosomus regius (Asso 1801)

The effect of 4 temperature levels, 17, 20, 23 and 26 °C was investigated on growth performance, feed and nutrient utilization, body, fillet and liver composition and morphometric characteristics of meagre, of initial mean weight 36.46 g, after a 12-week trial, fed on a practical diet composed of 49% crude protein and 16% lipids (dry weight). Furthermore, the gastrointestinal evacuation processes of meagre were monitored by subjecting fish to 48-h fasting period, followed by force-feeding and collecting the stomach and intestinal contents at 1 h, 2 h, 4 h, 6 h, 8 h, 12 h and 24 h post-feeding. Meagre growth parameters significantly improved with the increase in temperature, resulting in double the thermal growth coefficient (TGC) at 23 and 26 °C compared to 17 °C. Maximum weight (122.5 g) was achieved at 26 °C. Daily feed intake (DFI) increased from 17 to 26 °C, whereas nutrient efficiency and utilization parameters were significantly lower only at 17 °C. A time effect was also evident on the growth-related parameters and feed conversion ratio (FCR), resulting in similar specific growth rate (SGR) and TGC values between 23 and 26 °C and lower FCR only in 17 °C by the 3rd month, despite the initial difference amongst the 4 treatments. Intestine length increased as fish grew bigger with temperature increase, but the relative intestine length to fish total length remained constant. No effect of temperature was found on condition index (CI), hepatosomatic index (HSI), body proximate composition, fillet lipids and liver glycogen content. Liver lipid content significantly increased from 17 °C to 26 °C. Temperature influenced gastric evacuation patterns, but not the digesta moisture in each gastrointestinal tract (GIT) segment. Hydration within the GIT was affected by temperature with lower content obtained at 17 °C. Stomach digesta moisture and hydration significantly elevated 4 h post-feeding in all treatments. Within the intestine, unlike in the stomach, digesta were mostly comprised of moisture. Gastric evacuation rate (GER) became faster with temperature increase. Meagre juveniles required 4.3–7.4 h to half-empty their stomachs depending on temperature and more than 24 h to completely evacuate their GIT. 23–27 °C was determined as the best water temperature range for growth of meagre of 36-123 g under the specific culture conditions. At 17 °C growth and feed efficiency were impaired, while gastric evacuation processes deviated from the rest.

Growth response and feed utilization in Clarias gariepinus fingerlings fed diets supplemented with processed flamboyant (Delonix regia) leaf meal

Expanding utilization of conventional fish feed ingredients by man and fish feed industries has necessitated consideration of cheaper and locally available alternatives. A 70-day feeding trial was conducted to assess the effect of substituting graded levels of sundried flamboyant (Delonix regia) leaf meal (SFLM) for groundnut cake on growth and feed utilization of 240 Clarias gariepinus fingerlings at six substitution levels of 0 (control), 20, 40, 60, 80 and 100% in 12 plastic aquaria (50 × 40 × 40 cm). Each dietary treatment was randomly assigned in two replicates each to the aquaria making 12 treatment units and each aquarium had 20 fish. SFLM supplemented diets and fish carcass were proximately analyzed using standard procedures. Mean weight gain (MWG), specific growth rate (SGR) and feed conversion ratio (FCR) were determined. Data obtained were analyzed using descriptive statistics and ANOVA at p ≤ 0.05. Crude protein was highest (68.89%) in fish fed with diet 4, least (64.61%) in fish fed with diet 1 (control) and significantly (p &lt; 0.05) exceeded 60.54% of the pre-treatment fish carcass. Fish fed with diet 3 had significantly (p &lt; 0.05) higher values of MWG (11.73 g), SGR (2.13%/day) and superior FCR (0.451) above which growth and feed utilization indices progressively declined with increase in the substitution level of SFLM. This study revealed that 40% substitution level of the SFLM resulted in the best growth and feed utilization in C. gariepinus. The study demonstrated the considerable potential of flamboyant leaf meal as an alternative protein source, therefore other processing methods are recommended to increase its utilization, reduce feed cost and maximize aquaculture profitability.

Развитие фитопланктона в зимне-весенний период в прибрежных водах Крыма

Исследование фитопланктона в зимне-весенний период имеет важное значение для изучения особенностей его годовой динамики и функционирования экосистемы Чёрного моря в целом. Состояние фитопланктона в шельфовой зоне в зимне-весенний период по сравнению с таковым в летне-осенний сезон изучено слабо, поэтому проведение подобного исследования особенно важно для решения ряда проблем, связанных с продуктивностью конечных звеньев пищевой цепи, формированием гидрохимического режима вод и циклом углерода в море. Цель работы — оценить влияние сезонных условий на развитие фитопланктона и его продукционные показатели в зимне-весенний период в прибрежных водах Крыма. В статье представлены результаты исследований гидрофизических (температура, плотность, относительная прозрачность воды) и биологических параметров (концентрация хлорофилла a, его флуоресценция, таксономический состав и продукционные характеристики фитопланктона) в шельфовой зоне Чёрного моря в январе — апреле 2016–2019 гг. Исследования проведены на 50 станциях, расположенных в прибрежных водах Крыма от Каркинитского залива до Керченского пролива. Концентрация хлорофилла a определена стандартным флуориметрическим методом, видовой состав — с помощью микроскопирования; удельная скорость роста фитопланктона рассчитана по разработанной ранее модели. Зимой (январь — февраль) концентрация хлорофилла a и глубина верхнего квазиоднородного слоя были максимальными (0,42–0,52 мг·м−3 и 44–58 м соответственно), весной (март — апрель) — в 2–3 раза ниже. В январе — феврале доминировала примнезиевая водоросль Emiliania huxleyi (Lohmann) W. W. Hay &amp; H. P. Mohler, 1967; в марте — апреле в разные годы преобладали динофитовые и диатомовые водоросли либо примнезиевые, динофитовые и диатомовые. Зимой вертикальное распределение хлорофилла a на большинстве станций было равномерным; весной преобладали одномодальные профили с глубинным максимумом, расположение которого не было связано с градиентами температуры и плотности. Относительное изменение концентрации хлорофилла a и флуоресценции с глубиной имело, как правило, одинаковый характер. Продукция фитопланктона и суточный коэффициент P/B (production/biomass ratio) повышались от зимы к весне. Корреляция между величинами интегральной продукции, биомассой и максимальной удельной скоростью роста водорослей отсутствовала. Максимальная удельная скорость роста была наименее изменчивым показателем. В течение зимне-весеннего периода водоросли в зоне фотосинтеза делились в среднем 1 раз в 2–5 суток.

The Effect of Adding Bacillus NP5 to Feed on Growth, Survival Rate, and Protection Against Aeromonas hydrophila of Catfish (Clarias sp.)

Probiotics are useful organisms in preventing the spread of disease in aquaculture. Therefore this study aims to evaluate the effect of administering Bacillus NP5 on the growth, survival rate, and histology of catfish with Aeromonas hydrophila infection. To achieve this, catfish (7.75 ± 0.02 g) were reared for 45 days with a density of 20 per tank. Furthermore, the study consisted of 4 treatments and 3 replications, namely K+: 0% Bacillus NP5+0.1 mL A. hydrophila injection, K-: 0% Bacillus NP5 + without A. hydrophila injection, A: 0.3% Bacillus NP5, and B: 0.8% Bacillus NP5. The results showed that the addition of probiotics significantly increased the growth and survival rate of catfish (P <0.05) compared to K+. The higher value of specific growth rate was found in treatments A and B (0.22 ± 0.03 and 0.23 ± 0.03% day-1, respectively) and the lowest in K+ (0.14 ± 0.03% day-1). Also, the tissue damage in K+ was higher than in the probiotic treatment. Besides, hyperplasia, congestion, and secondary lamella fusion in the gill tissue were found in the K+, while other treatments were found only in hyperplasia. Melanomacrophages occurred in catfish kidney tissue for all treatments, however, hydropic degeneration was found in the control treatment. The addition of Bacillus NP5 in feed resulted in higher growth, survival, and tissue damage compared to K+. Also, the addition of 0.8% Bacillus NP5 resulted in less catfish tissue damage.

Tratamiento de aguas residuales con aceite de motor empleando un biorreactor de lecho empacado usando un consorcio microbiano nativo inmovilizado

Waste motor oil generates contamination in water due to its inappropriate disposal and is hence considered a hazardous residue. In this study a native microbial consortium was isolated from soil contaminated with waste motor oil. The ability to grow, biosurfactant production, and degradation of different oil concentrations (0.2, 0.5, 1.0, and 2.5 % v v-1) was analyzed. The growth kinetic analysis revealed the value of the maximum specific growth rate was 0.758 d1, while the saturation constant was 0.781 % v v-1 (7.11 mg mL-1) and the inhibition constant, 2.60 % v v-1 (23.77 mg mL-1). Waste motor oil (1.0% v v-1) was used in the biodegradation oil studies using a packed-bed bioreactor and native microbial consortium immobilized over plastic rings. The results obtained showed the biosurfactant production capacity was 398.18 mg L-1 and the efficiency of waste motor oil was 67.76%. The results obtained in the present work represent a significant advantage in bioremediation of oil contaminated water.

Effect of dietary protein level on growth, food utilization, food conversion and survival rate of giant trevally (Caranx ignobilis)

Background: Proper feed formulation is required for successful fish farming activities. Therefore, it is necessary for fish feed to provide optimal growth so that the cultivation business generates profits. Currently, there is very limited information about the appropriate feed for Caranx ignobilis, causing problems with its development. This study aims to provide feed with different protein levels to C. ignobilis. Methods: We will examine the protein levels’ effects on the daily growth rate (DGR), specific growth rate (SGR), absolute growth rate (AGR), feed conversion ratio (FCR), feed efficiency (FE), and survival rate (SR). This research was conducted for 35 days, from June to October 2017, at the Center Brackiswater Aquaculture Development (BPBAP) Ujung Batee, Ministry of Marine Affairs and Fisheries, Aceh Besar, Indonesia. This study used a completely randomized design method, with five treatment levels (30%, 40%, 50%, 60%, and 70% protein feed) and four replications. Results: The results showed that feeding with different proteins on C. ignobilis had a significant effect on the mean values ​​of DGR, SGR, AGR, FCR, FE, and SR. The 50% protein feed gave the best results for C. ignobilis, with a mean DGR value of 0.267 ± 0.005 g / day, a mean SGR of 1.722 ± 0.030% / day, a mean AGR of 0.081 ± 0.003 cm/day, a mean FCR of 1.290, a mean FE 77.755% and a mean SR was 86.667%. Conclusions: Furthermore, feed treatment with increased protein content between 30%–50% has a positive correlation with the growth of C. ignobilis. However, the ability to grow fish will decrease if the feed protein content is &gt;50%.

Substitution of commercial feed with fermented banana peel flour (Musaceaea sp.) and fish meal to feed consumption level, specific growth rate, feed efficiency, fat retention, and energy retention in siam catfish (Pangasius hypophthalmus)

This study aims to investigate the effect of commercial feed substitution with fermented banana peel flour and fish meal on feeding rate, specific growth rate, feed efficiency, fat and energy retention. This study used a Completely Randomized Design which consisted of 5 treatments: P0 (100% commercial feed), P1 (commercial feed 95% + 5% FTKPTI), P2 ( commercial feed 90% + 10% FTKPTI), P3 (commercial feed 85% + 15% FTKPTI), and P4 (commercial feed 80% + 20% FTKPTI). Data were analyzed using Analysis of Variance (ANOVA) and continued with Duncan’s Multiple Range Test. The results of statistical analysis showed that commercial feed substitution using fermentation of banana peel flour (Musaceaea sp.) And fish meal resulted in feed consumption values, specific growth rates, feed efficiency, fat retention and energy retention which had no significant differences (p> 0.05). This shows that commercial feed substitution using fermentation of banana peel flour (Musaceaea sp.) and fish meal up to a dose of 20% in feed has the same feed consumption, specific growth rate, feed efficiency, fat retention and energy retention values as well as the control feed.

Effects of Feeding Frequency on Growth Performance and Production of Labeo rohita (Hamilton, 1822) Reared in Cage

Optimum feeding schedule is one of the main things for the proper growth of fish and other animals. A study was conducted to optimize the effects of different feeding frequencies on growth performance and production of Rui (Labeo rohita) under pond cage culture system in Rajshahi, Bangladesh. Labeo rohita with an average weight of 302.23±4.07g (mean ± SD) were randomly stocked in 9 cages at 30 fish/cage in all the treatment. Fish were fed (4% of body weight) a commercial floating feed with three different feeding schedules: feeding of fish thrice daily in T1treatment; twice in T2 treatment and once in T3 treatment. Water quality parameters were measured during the study period. The physico-chemical parameters of pond water were within suitable ranges for fish culture in cages. The obtained values of the water quality parameters were temperature 28.26 to 28.46°C, pH 6.91 to 6.94, DO 5.04 to 5.33 mg/l, CO2 2.95 to 3.02 mg/L. The mean final weight gain was significantly highest in T1 (345.05 g) a followed by T2 (324.66 g) and T3 (257.82 g). The Specific growth rate (SGR) value were significantly higher in T1 treatment (0.91% bwd-1; Body weight per day) than T2 (0.87% bwd-1) and T3 treatment (0.73% bwd-1). The feed conversion ratio (FCR) value was significantly lower in T1 fish group (2.72) than other two T2 (2.84) and T3 (3.44) treatments. The fish productions were 18.13, 17.55 and 15.67 kg/cage/cycle in T1, T2 and T3 respectively. The highest net profit was found (Bangladeshi Taka, BDT 1445.38) in T1 compared to T2 (BDT 1329.24) and T3 treatment (BDT 937.99). The cost benefit ratio (CBR) was significantly higher in T1 (0.57) than T2 (0.53) and T3 (0.37). The feeding schedule three times in a day was most suitable than other two schedules.

Effects of Caulerpa lentillifera added into culture media on the growth and nutritional values of Phronima pacifica, a natural fish-feed crustacean

Abstract. Herawati VE, Pinandoyo, Ariyati RW, Rismaningsih N, Windarto S, Prayitno SB, Darmanto YS, Radjasa OK. 2021. Effects of Caulerpa lentillifera added into culture media on the growth and nutritional values of Phronima pacifica, a natural fish-feed crustacean Biodiversitas 22: 424-431. Phronima pacifica is a microcrustacean commonly used as natural feed in fish farming as it has high nutrient contents and is suitable based on larval fish mouth gap size and mass cultivation capacity. However, P. pacifica is not produced optimally and its supply is inadequate, so that P. pacifica culturing techniques need to be improved. The culture of P. pacifica is mostly done using sea grape seaweed (Caulerpa lentillifera). The aim of this study was to investigate the optimal stocking density of C. lentillifera added into media culture on the growth and nutritional values of P. pacifica. We applied a complete random design experiment with four treatments of stocking density of C. lentillifera (i.e., 0 g/m2 (Control), 20 g/m2, 40 g/m2, and 60 g/m2) with 3 replicates for each treatment. The following parameters were analyzed, namely specific growth rate (SGR) of C. lentillifera, and the growth, biomass, growth rate, proximate analysis, and amino and fatty acid concentrations of P. pacifica. This study found that the addition of C. lentillifera into culture media significantly enhanced the growth of P. pacifica. The highest effect on the growth was observed in the treatment of 60 g/m2 with C. lentillifera SGR value of 4.76 ± 0.12%/day, and P. pacifica growth rate, population density and biomass of 4.41 ± 0.12 ind/day, 53.81 ± 8.79 ind/L, and 1.14 ± 0.14 g, respectively. Similarly, the highest protein and fat contained in P. pacifica was obtained in the treatment of 60 g/m2 with 60.23% protein and 10.24% fat. Furthermore, the highest fatty acid profile was C20: 5n-3 of 13.23% ± 0.08% and amino acid profile of 45.23% ± 0.01%. The application of the optimal stocking density of C. lentillifera in culture media could increase the growth and nutritional quality of P. pacifica which in turn could enhance aquaculture productivity.