Plastic Tanks Research Articles

Effects of Substituting Soybean Meal by Unprocessed and Processed Peanut Cake Meal on the Growth, Body Composition and Survival of Tilapia (Oreochromis niloticus)

An 8-week feeding trial was conducted to investigate the effects of replacing soybean meal by unprocessed and processed peanut cake meal on the growth, body composition and survival of Nile tilapia fry. Five types of feed were produced: diet 1 containing unprocessed peanut meal (natural NPM), diet 2 toasted peanut meal (toasted TPM), diet 3 fermented peanut meal (fermented FPM), diet 4 steamed peanut meal (steamed SPM) and diet 5 containing soybean meal (SBM). For the diet containing FPM, the fermentation of the mill mixed with yeast lasted 7 days anaerobically. The diet containing SPM was formulated with a steam-treated cake on a couscous steamer held on a kettle. The diet made with TPM underwent heat treatment on a stove. The remaining part of the cake NPM did not undergo any transformation. The experiment was conducted in an open system at the University of Cheikh Anta Diop and lasted nearly for two months. The fish were first subjected to acclimatisation phase prior to the initiation of the trial. The five treatment diets were triplicated and the stocking density was 15 fish per tank with a total of 225 fry with an initial average weight of 0.13 g. The fish were raised in plastic tanks of 50L each and fed three times a day (9 a.m, 1p.m and 5 p.m) at a feeding rate of 8% and 3% of their body weight during the 1st, 2nd to 3rd and 4th 2 weeks respectively. The temperature and dissolved oxygen were monitored in the morning and evening and the culture units were cleaned, siphoned and refilled with water at two third of their capacity prior to the feeding. The results of this study indicated that dietary NPM and TPM could replace SBM without a negative impact on the growth of tilapia. The FCR of the fish fed the diet containing NPM, SPM, TPM are not significantly different with FCR of those fed SBM. There were effects on the body composition of the fish fed diets containing the substitution of soybean meal with processed peanunut cake. The survival rate varied from 93 to 100%. The results of the analysis of the aflatoxin level in the four types of feed containing peanut meal showed that the heat treatment had no effect on the aflatoxin content. The substitution of soybean meal with natural and toasted peanut cake has no adverse effect on growth and feed efficiency of Nile tilapia fry. The authors suggested to use natural or toasted peanut cake for better growth.

Effect of Marjoram Origanum majorana L. Extract on Growth Performance and Some Haematological Parameters of Common Carp Cyprinus carpio L.

The current study examines the effects of different levels of marjoram Origanum majorana extract (0, 0.5, 1.0, and 1.5 %) on growth performance and haematological parameters in diets of common carp Cyprinus carpio. Four units of the Recirculating Aquaculture System (RAS) were used. Each unit had three plastic tanks (30×30×60 cm), representing four treatments with three replicates, each tank containing ten fish with an average weight of 16.31 + 0.02g - 16.48 + 0.10. Fingerlings were fed at a rate of 3% of the total fish weight. All diets contained an average of 33.89 ± 0.067 % crude protein and about 20.32±0.16 (kJ/g) of gross energy. Fish are fed twice daily, six days a week. The study lasted eight weeks (56 days) during November and December 2021. According to our findings, a group of fish fed 1.5% marjoram extract had the highest rate of final body weight, daily weight increase, relative growth rate, specific growth rate, food conversion ratio, and feed conversion efficiency. The 1.5 % marjoram extract treatment had the highest rate of total protein +5.68 0.84 g/dl, albumin +4.48 0.48 g/dl, globulin +1.17 0.54 g/dl and 3.82 + 0.51% albumin/ globulin. Based on the results, it can be concluded that the use of 1.5 % O. majorana extract was best for growth, and blood profile. The results suggest that the inclusion of O. majorana can improve the nutrient efficiency, growth performance, and haematological parameter of C. carpio fingerlings without negative effects on the fish.

Effects of Pretilachor Pyribenzoxim Pollution on the Water Quality, Serum Biochemical Indices, and Behavioural Response of Oreochromis niloticus Juveniles

Aims: The effects of Pretilachor pyribenzoxim (PP) pollution on the water quality, serum biochemical indices, and behavioural response of Oreochromis niloticus Juveniles were studied.
 Study Design: The completely randomized design was used in this study.
 Place and Duration of Study: The experiment was carried out in the Central Laboratory of the Fisheries and Aquaculture Department, Faculty of Agriculture, Adekunle Ajasin University Akungba-Akoko, Nigeria, between January and March 2023.
 Methodology: The experiment was carried out in 30 L of non-chlorinated and aerated water in rectangular plastic tanks (45cm x 30cm x 30cm). 250 juveniles O. niloticus of both sexes were collected from Federal University of Technology, Akure, Ondo state and acclimatized for 14days in the laboratory. During rearing period, the fish were fed coppen feed at 2% body weight. In a definitive test, a group of 10 fish specimen (11.3-17.5cm length and 10.5-32.3g weight) were treated at random to nominal PP doses of 0.0, 0.10, 0.125, 0.150, 0.175, and 0.2 ml being diluted in 30 litres of water and labelled T1. T2, T3, T4, T5 and T6, respectively in triplicate. The LC50 of PP, test water's physicochemical, behavioural responses and serum biochemical indices were determined.
 Results: The dissolved oxygen depleted (P<0.05) in T5 and T6, compared to T1 and the rest of the treatments. The water conductivity increases (P<0.05) with an increased concentration of PP contamination. The water's total dissolved solids levels increased progressively with an increase in PP concentration. The total dissolved solids in T5 and T6 were similar (P>0.05) to T4 but lower (P<0.05) than T1 and T2. Juveniles in treatments 2, 3, 4, 5 and 6 shows behavioural responses such as loss of reflex, fin deformation, erratic swimming, air gulping, and moulting. The serum total protein of the juveniles in treatments 2, 3, 4, 5 and 6 was lower (P<0.05) than T1. Serum creatinine level increased with increased PP contamination from treatments 1 to 6. The serum aspartate aminotransferase (AST) of the juvenile in T3, T4, T5 and T6 were higher (P<0.05) than in T1. The serum Alanine aminotransferase (ALT) of the juvenile in T2, T3, T4, T5 and T6 were significantly (P<0.05) higher than T1.
 Conclusion: The exposure of juvenile O.niloticus to PP contamination affected the physicochemical properties of water, behaviour and Serum biochemicals of juvenile O. niloticus fish. Hence, leaching of pp into water bodies through Agricultural activities should be mornitored to reduce lost of fish which can lead to economic detune.

Ureagenesis of Asian seabass (Lates calcarifer) under ammonia stress and overcrowding

Ammonia, an excretory substance resulting from the catabolism of proteins and amino acids, is toxic to fish. Increasing ammonia, due to overcrowding fish in a tank, results in dropping production efficiency. This study aims to investigate the adaptation of Asian sea bass to increased ammonia content in fish tanks with different populations. Five groups were tested in 250-l plastic tanks: group A: 15 fish (6 g/L), group B: 20 fish (8 g/L), group C: 25 fish (10 g/L), group D: 30 fish (12 g/L), group E: 35 fish (14 g/L). The ammonia level in the tanks was measured daily. After 60 days, the activity of some enzymes and biochemical parameters related to ammonia was measured in muscle, liver, and blood. The results were statistically analyzed. After hypoxia, in the overcrowded group, the level of liver glycogen and blood glucose fell; the blood lactate and muscle adenosine monophosphate deaminase (AMPD) activity increased; the activity of muscle glutamate dehydrogenase (GDH) increased; the activity of glutamate dehydrogenase, glutaminase, arginase, and aspartate transferase (AST) of the liver increased. Due to the increased activity of urea cycle enzymes in the liver, urea was detected in the blood. One of the strategies that Asian sea bass adopts in dealing with a high level of ammonia is to activate the urea cycle in the liver and turn ammonia into urea to control it. This way is a type of adaptation to ammonia stress that was not identified in this species before.

Thermal neutron measurement in the STU Mini Labyrinth experiment

As part of an international cooperation the research team from the Slovak University of Technology is involved in the development of new radiation shielding experimental workplaces for code verification and demonstration of radiation shielding principles. One of these activities is the so called “Mini Labyrinth” experiment. It is a simple neutron and gamma shielding benchmark, inspired by the ALARM-CF-AIR-LAB-001 ICSBEP experiment. The STU Mini Labyrinth, as its name implies, is a mini version of the original IHEP Labyrinth, currently with dimensions of 96 × 60 × 25 cm. The experimental setup is placed on a special deck in the neutron physics laboratory of STU and uses remote source handling mechanism and video surveillance. It consists of several NEUTRONSTOP C5 shielding blocks (polyethylene with 5% boron), several detector positions and two channels to insert the neutron source and to generate thermal neutrons. The first one is a plastic tank filled with liquid moderator and a second one is a solid graphite prism, which is ideal to produce thermal neutrons. In the previous works of the research team, efforts were made to find the best setup for measurement inside and outside the Mini Labyrinth. It was found out that the 25 cm height was not appropriate, therefore it was increased to 50 cm by adding an extra level of NEUTRONSTOP blocks. This paper brings the results of first measurements performed on the V3-50-R measurement geometry and their comparisons with simulations using the Monaco code from the SCALE 6 system. In this measurement setup, the neutron source is placed inside the graphite prism and the aim is to measure and simulate the thermal neutron count-rate.

Water Renewal Frequency Affects Water Quality, Growth Performane and Physiological Staus of African Catfish, <i>Clarias gariepinus</i> Juveniles

A 56-day experiment was undertaken to assess the influence of water changing frequency on the water quality, growth performance and physiological status of African catfish, Clarias gariepinus juveniles. There were three treatments with different water changing regimes, every two days, every four days and once a week. Nine plastic tanks were stocked with ten African catfish (10.39±0.36 g) each in triplicates for the three treatments. The fish were fed at 5% body weight daily. Selected water quality parameters were examined twice a week, while growth performance and physiological parameters were measured at the end of the eight weeks. pH, temperature and nitrate-nitrogen were not different significantly among the treatments. The highest total ammonia-nitrogen (0.55±0.01 mg L-1 ) was observed in the treatment with water changes once a week, and it was significantly higher than the treatment with water changes every two days. Both total dissolved solids and electrical conductivity were also different among the treatments. Growth performance improved with decreased frequency of changing water; weight gain, specific growth rate and yield were all higher significantly in the treatment with water changes once in a week compared to every two days. Nutrient utilization, survival and body indices were not different significantly among the treatments. Higher glycogen and healthier livers were noted in the treatment with water changes once a week. The result established that changing the water once a week for fish stocked up to 20 Kg m-3 may confer more advantages on the fish and lead to improved performance.

An investigation into the effects of using protein hydrolysate in low fish meal diets on growth performance, feed utilization and health status of snakehead fish (Channa striata) fingerling

This study aimed to investigate the growth performance, feed utilization and innate immune response of snakehead fish (Channa striata) that had received a low fish meal-based diet and supplementation with protein hydrolysate. A fish meal-based diet was consider as a ‘high fish meal diet’ in feed formular (HF) and a ‘low fish meal diet’ (LF) replaced 40% of fish meal with soybean meal. Two other diets were prepared by supplementing tuna hydrolysate (TH) and poultry hydrolysate (PH) in LF diet. The experimental fish (initial mean weight 4.1 ± 0.15 g) were randomly assigned to quadruplicate group and fish were randomly distributed into 500-L circular plastic tanks at a density of 70 fish per tank. Each experimental diet was handfed three times daily to apparent satiation for eight weeks. At the terminal period, the results showed no significant difference in fish survival rates among all groups (p > 0.05), and significant improvements (p < 0.05) in percentage of weight gain and specific growth rate were obtained in fish fed dietary TH compared to among all group. In terms of feed utilization, the data showed that there was also no significant difference (p > 0.05) in feed conversion ratio (FCR) and protein efficiency ratio (PER) among all groups. Values of hematological parameters did not significantly differ among experimental groups (p > 0.05). Serum lysozyme levels increased significantly in fish fed diet TH. Other immune parameters (Catalase, MPO, SOD and RBA) were not altered by diet. However, fish fed diet TH and HF had strong fluorescence intensity, indicating slightly higher respiratory burst activity than other groups. Overall, the present findings suggest that supplementing 2.5% tuna hydrolysate in the low fish meal-based diet can improve feed intake, growth performance and innate immunity in snakehead fish.

Effects of dietary β-mannanase (Hemicell®) and Lavandula angustifolia on Oreochromis niloticus fed a low level of dietary protein: Growth, digestive enzymes, and hemato-biochemical indices

High feed prices and limited access to feed are two critical problems faced by fish producers. One approach that farmers may consider is using less expensive and locally available components. We conducted a 60-day feeding trial to investigate the consequences of the dietary addition of Hemicell® (HC) as exogenous β-mannanase and lavender flower meal (LFM) in low- protein diet (25 % CP) in Oreochromis niloticus. The investigation assessed growth, feed utilization, somatic, body composition and hemato-biochemical indices, and digestive enzyme activity. Fish (N = 180; average weight: 17.17 ± 0.72 g) were haphazardly organized into six groups in triplicates (10 fish/replicate) and stocked in 18 plastic tanks (60 L). For 60-days, fish groups were fed on six prepared experimental diets. The negative control group (NCG) and positive control group (PCG) were fed basal diets containing 30 % CP and 25 % CP, respectively. Groups (G1-G4) were fed on basal diets containing 25 % CP and supplemented with 0.25 g/kg HC, 0.5 g/kg HC, 0.25 g/kg HC+ 10 g/kg LFM, and 0.5 g/kg HC+ 10 g/kg LFM, respectively. The findings showed decreases in the growth, body composition (crude protein and lipids), and white blood cells count (WBCs) in PCG as compared with the control group (NCG); meanwhile, no significant alteration was recorded for other parameters. Dietary addition of HC alone or with LFM enhanced growth, feed utilization, digestive enzymes activity (trypsin, amylase, and lipase), serum total protein, and hematological indices (red blood cells count, WBCs, and Hb) as compared with PCG. The highest results were notable in G2. No marked impacts were observed on water quality parameters, fish survival, somatic index (hepato-somatic and visceral-somatic), and the level of cholesterol, glucose, and creatinine in fish serum by dietary HC or LFM. However, values of triglycerides, urea, hepatic enzymes (alanine and aminotransferases), and body crude lipids increased by supplementation of HC alone or with LFM. Our findings demonstrated that feeding O. niloticus a low-protein diet supplemented with HC (0.5 g/kg) could promote growth, digestive capability, and health status. This provides a platform for potential exogenous enzyme (HC) use in low-protein diets to reduce feed costs and support the aquaculture industry.

The Effect of Ammonia Accumulation on Growth and Survival of African Catfish Fingerlings

The purpose of this study was to investigate the effects of ammonia concentration with various levels on the growth and survival rate of African catfish fingerlings and the change of water quality throughout the nursing periods. The experiment was Completely Randomized Design (CRD) 4 treatments each having 4 replications. Treatment 1 did not perform the water exchange and in treatment 2-4, 50 percent of water were exchanged when accumulated ammonia was 1-2, 4-5 and 25-26 mg/L, respectively. The experimental animals aged 15 days. The average initial weight were 0.42±0.03 g. and 3.85±0.11 cm., respectively. The fingerlings were fed floating pellets with 35 percent protein levels. Feeding was done 3 times a days. Nursing was conducted in a plastic tanks containing 50 liters freshwater with 50 fishs per tank. The duration of the experiment was 31 days. The results found that the water exchange at the ammonia levels of 1-2 and 4-5 mg/L, affected the highest growth of the fingerlings and higher than the control. (P≤0.05) Water exchange when ammonia 1-2 mg/L, the survival of fingerlings was higher than that in all experiments. (P≤0.05) This condition also used 15 liters of water per fish, pH between 7.03-7.87, temperature between 28.24-30.03 ºC, alkalinity between 76.67-193.75 mg/L, dissolved oxygen 0-4.85 mg/L and turbidity between 0-51.70 NTU.

Field tests on Fiber-Reinforced Plastic (FRP) stormwater storage tank under road pavements for “Sponge City” development

Urban flooding has become one of the major issues in many cities around the world, due to rising sea level, increasing precipitation intensity, and land development. This research aims at the development of underground storage tanks (USTs) using fiber-reinforced plastic (FRP) materials for stormwater detention, storage, and reuse. The USTs are proposed to be placed underneath road or highway pavements. FRP as one of the emerging structural materials possesses several advantages including high strength-to-weight ratio and excellent corrosion resistance, compared with steel and other conventional materials. The mechanical performance of FRP USTs has rarely been investigated in existing literature; the majority of the existing studies have generally focused on leakage issues and associated environmental problems. This paper presents the results of the first-ever field test on an FRP UST buried underneath a pavement subjected to traffic loads. Sophisticated instruments using optic fiber sensors were installed to measure the responses of the FRP UST. The influences of traffic location and the water storage on the behavior of the FRP UST were investigated. The test results demonstrated the reliability of the FRP UST in resisting the traffic loads. Finally, finite element modelling was conducted to simulate the test results. The insights gained from the field test and the finite element analysis are expected to provide a general guidance on the design of FRP USTs under road pavements for “Sponge City” development.

Effects of Yellow Mealworm (Tenebrio molitor) on Growth Performance, Hepatic Health and Digestibility in Juvenile Largemouth Bass (Micropterus salmoides).

This study investigated the effects of yellow mealworm meal (TM) on growth performance, hepatic health and digestibility in juvenile largemouth bass (Micropterus salmoides). The fish were fed with the basic feed and the test feed (70% basic feed and 30% raw materials) containing Cr2O3, and feces were collected for digestibility determination. The fish were fed with five isonitrogenous (47% crude protein) and isolipidic (13% crude lipid) diets, in which fishmeal (FM) was replaced with 0% (TM0), 12% (TM12), 24% (TM24), 36% (TM36) and 48% (TM48) TM. The fish were reared in cylindrical plastic tanks in a recirculating aquaculture system for 11 weeks. The apparent digestibility coefficients (ADC), of dry matter, crude protein and crude lipid, in largemouth bass of TM were 74.66%, 91.03% and 90.91%, respectively. The ADC of total amino acid (TAA) of TM in largemouth bass was 92.89%, and the ADC of essential amino acid (EAA) in TM in largemouth bass was 93.86%. The final body weight (FBW), weight gain rate (WGR) and specific growth rate (SGR) in the TM24 group were significantly higher than those in other groups. Similarly, the highest mRNA expression levels of hepatic protein metabolism genes (pi3k, mtor, 4ebp2 and got) and antioxidant enzyme (glutathione peroxidase, Gpx; catalase, Cat) activities were observed in the TM24 group. Moreover, the expression levels of anti-inflammatory factors (il-10 and tgf) in liver were up-regulated and the expression levels of pro-inflammatory factors (il-8 and il-1β) in liver were down-regulated. Quadratic regression model analysis, based on weight gain rate (WGR) against dietary TM level, indicated that the optimum level of dietary TM replacing FM in largemouth bass diet was 19.52%. Appropriate replacement levels (less than 36%) of FM by TM in the diets can enhance the antioxidant capacity and immunity of largemouth bass. However, high levels of FM substitution with TM (more than 48%) in the feeds can damage the liver health and inhibit the growth of largemouth bass. Notably, largemouth bass has high ADC and high utilization of TM, which indicates that it is feasible to use TM as feed protein source for largemouth bass.

Phytoremediation of domestic sewage using a floating wetland and assessing the pollutant removal effectiveness of four terrestrial plant species

Abstract Several developing countries have limited infrastructure and finance to treat domestic and industrial wastewater. Discharging untreated sewage pollutes the surface and groundwater. Floating wetlands are an alternate method for treating polluted surface water bodies. This study's objective is to investigate the remediation of domestic wastewater using natural buoyant bamboo as a floating raft and terrestrial plants such as Ocimum tenuiflorum, Hibiscus, Chrysopogon zizanioides, and Canna in the floating wetland treatment (FWT) system. Floating rafts with a healthy terrestrial plant were planted and made to float in four plastic tanks with domestic wastewater. The water quality analysis was carried out periodically after 0, 3, 5, 10, 15, 20, and 25 days intervals. The experimental results of FWT using C. indica showed the highest removal efficiency of the pollutants such as TSS (96%), TP (98%), ammonia (95%), and DO (45%). In contrast, Ch. zizanioides showed its maximum removal efficiencies for turbidity (90%), TDS (48%), TN (85%), sodium (53%), potassium (74%), TP (92%), EC (27%), COD (93%), BOD (95%), and E. coli (47%). This study finding showed that the best terrestrial plants for removing various nutrients and other contaminants from municipal sewage were C. indica and Ch. zizanioides. However, further research is required to utilize these terrestrial plants with substrates under long-term study.

Sustainable Manufacturing Process Applied to Produce Waste Polymer-Polymer Matrix Composites

Getting rid of plastic and rubber waste is one of the goals of achieving a sustainable lifestyle. Out-of-service tires and fuel and water tanks manufactured from polyvinyl chloride (PVC) are the most common waste that cities suffer from. This paper aims to investigate the effect of reinforced waste polymer particles on the polyester resin matrix when producing polymer matrix composite materials from waste tires and damaged plastic water tanks with different polymeric percentages. The polymer matrix composite could be used later in different applications, such as insulators and vibration dampers. The composite materials were evaluated by measuring the Shore D hardness, tensile strength, modulus of elasticity, and coefficient of thermal conductivity. The overall results showed hopeful behavior. Mixing a specific mixture of waste PVC and tires with polyester and hardener gives a higher tensile strength, modulus of elasticity, and Shore D hardness compared to each material when used separately. The thermal conductivity values increase with the mixing conditions between the materials. The thermal conductivity values can be reduced by using higher percentages of a mixture of waste tires and polyester or PVC and polyester. A 4.5% PVC, 4.5% tire and 91% (polyester and hardener) mixture can be recommended to improve tensile strength performance. A mix of 8.3% PVC, 8.3% tire, and 83.4% (polyester and hardener) can be recommended for high hardness.

Sobaity Seabream Culture in High‐Temperature Conditions

AbstractThe survival, growth performance, feed intake, and feed conversion ratio of cultured Sobaity Seabream Sparidentex hasta in local high temperatures of 24, 28, and 32°C were estimated in this study. Experiments were conducted in triplicates with 40 fish (99 g average body weight; 17 cm average total length) in each indoor 1‐metric‐ton fiber‐reinforced plastic tank. For 96 d, the fish were fed a commercial diet (6‐mm pellets, 46.36% crude protein, and 12.54% crude lipid). The results showed that survival and growth performance of juvenile Sobaity Seabream were affected by temperature. Total weight gain was significantly higher in the 32°C group (158.57 g), followed by the 28°C group (138.25 g), and the lowest weight gain was observed in the 24°C group (116.98 g). The feed conversion ratio (1.62) was significantly lower in the 32°C group than in the 28°C (1.8) and 24°C (1.85) groups. Feed intake was significantly higher in the 32°C and 28°C groups (6.20–6.43 g) than in the 24°C group (5.41 g). In the 32°C group, the survival rate was significantly lower. The condition factor showed no significant difference among the three temperatures. Overall, Sobaity Seabream farming is feasible at temperatures ranging from 24°C to 32°C.

Prevalence of Aeromonas species in Clarias gariepinus and water from different culture facilities in fish farms in Kwara State, Nigeria

Aeromonas species are associated with diseases on fish farms leading to mortality and economic losses. In order to determine the prevalence and diversity of Aeromonas species from water and Clarias gariepinus cultured in the different holding facilities; five hundred and seventy six Clarias gariepinus fish and one hundred and eight water samples were randomly sampled from fish farms in Kwara State. The samples were clinically and bacteriologically examined and confirmed using Oxiod rapid microbat identification test kits for Gram-negative bacteria, Microbact 24E (MB24E). The overall prevalence of Aeromonas species from water from the different cultured facilities revealed water sampled from earthen ponds had the highest prevalence of 66.67 % followed by concrete tanks with a prevalence of 41.66 % and the least prevalence of 30.56 % was recorded for water in plastic tanks. A similar pattern was recorded in Clarias gariepinus from the different holding facilities showing that earthen ponds had the highest prevalence of 40.10 % when compared with concrete tanks 28.65%, and to plastic tanks 20.83 %. Four varying diversities of Aeromonas species comprising of Aeromonas hydrophila, Aeromonas caviae, Aeromonas veronii biovar sobria, and Aeromonas veronii biovar veronii were isolated from both water and fish from the different holding facilities. From this study, cultured Clarias gariepinus were susceptible to Aeromonas species irrespective of the culture facilities. Therefore, there is need for proper management practices and adherence to biosecurity measures to prevent the outbreak and spread of diseases on the farms.

Digestibility, Blood Profile and Enzyme Activity of Clarias gariepinus (Burchell, 1822) Fed Diets Containing Sweet Potato Peel

This study evaluated digestibility, haematological indices and enzymes activities of Clarias gariepinus fed sweet potato peel as a replacement for maize. Five experimental diets were formulated at a crude protein of 35% using Pearson’s square method; maize was replaced by sweet potato peel in the diets at 0%, 25%, 50%, 75% and 100%. Fifteen plastic tanks of 200-litres each were used. 10 juveniles of C. gariepinus were introduced into the experimental tanks. The fish were fed at 5% biomass twice per day. The experiment lasted for 12 weeks. The fish fed 100% sweet potato peel gave the best digestibility coefficients contents of 43.17%, 65.44% and 95.12% for apparent ash, fat and protein digestibility, respectively. The fish fed 100% sweet potato peel recorded the highest packed cell volume of 27.75% in the blood while the least percentage of 23.21 was recorded in the fish fed 25% sweet potato peel. The lipase activity was highest (0.79U/mg) in the fish fed 100% sweet potato peel while the fish fed 25% sweet potato peel had the least (0.47U/mg). This research revealed that the enzymes activities were the main factors that activated the experimental fish to assimilate the sweet potato peel more efficiently.

English

A 12-week feeding trial was conducted to evaluate the effects of replacing fishmeal with black soldier fly larvae (BSFL) meal on growth performance and carcass composition of African catfish fingerlings. Five isonitrogenous (40% CP) diets of 0 (Control), 25, 50, 75 and 100% fishmeal with BSFL were used in triplicate. A randomized complete block design was used, and 600 fingerlings (0.46&plusmn;0.02g) were randomly selected and stocked at a rate of 40 fingerlings in 15 plastic tanks respectively. Results showed that the treatment diets significantly (P&lt;0.05) affected growth indexes, feed utilisation indices, and carcass composition of fish. Furthermore, 25% fishmeal could be replaced by BSFL meal without significantly reducing growth indexes and feed utilisation indices. However, water quality and condition factors between treatments were not significantly (P&gt;0.05) affected by the diets. Decreased concentration of crude protein, ash, nitrogen free extracts in carcass composition of fingerlings with corresponding increase in dietary BSFL meal inclusion was observed. Increasing inclusion levels of BSFL meal and decreasing levels of fishmeal increased the concentration of ether extracts and fibre contents of the body composition. Therefore, BSFL meal protein can be used to partially replace fish meal up to 25% to improve growth performance and feed utilisation. Key words: Feed utilization, fishmeal, indices, insect meal, proximate analysis.

Partial dietary fishmeal replacement with mixture of plant protein sources supplemented with exogenous enzymes modify growth performance, digestibility, intestinal morphology, haemato-biochemical and immune responses for Nile tilapia, Oreochromis niloticus

For the aquaculture sector, expanding the amount of plant proteins substituting fish meal (FM) is favorable. This study was conducted to evaluate the properties of diets containing a blend of plant protein sources (cotton seed meal, sunflower meal and jojoba (CSJ)) instead of FM and supplemented with a mixture of exogenous enzymes on the growth performance, intestinal morphology, blood indices, activity of endogenous and digestibility also, immune response of Nile tilapia, Oreochromis niloticus. Three groups of the experimental diet (29.5% crude protein) and (18.76 MJ kg −1 gross energy) were performed. The first group CSJ1 was (FM: CSJ = 2:1), the second group diet CSJ2 was (FM: CSM = 2:2) and the third CSJ3 was (FM: CSJ = 2:1), the replaced was based on content of protein. All groups of diets were supplemented with mixture of enzymes (Protease, pepsin, trypsin, xylanase and amylase) at 0 and 0.5 g kg −1 diet therefore six diet was formulated. Fingerlings (6.30 ± 0.09 g) were randomly allocated into eighteen plastic tank (450 L capacity) in triplicate per each treatment (25 fish/ treatment) for 90 days. After 90-days of the feeding trial, results indicated that the highest wight gain and best FCR, higher (P < 0.05) activity of trypsin and lipase, apparent digestibility coefficient of nutrients were detected in fish fed diet of FM: CSJ 2:1 and 2:2 supplemented with 0.5 g enzymes mixture kg−1 diet with insignificant differences between group. The diet incorporating FM: CSJ 2:1 with 0.5 g enzymes mixture showed the maximum (P < 0.05) villi length/width, ASA, and MSR values. Fish fed a diet containing FM: CSJ 1:2, and supplemented with 0.5 g of an enzyme mixture kg−1 diet had the maximum Hb, Htc, RBCs and WBCs values (P < 0.05). The highest (P < 0.05) TP and GL value was estimated in diet containing FM: CSJ; 1:2 without the addition of enzymes mixture. while, the best (P < 0.05) value of ALT and AST were showed in diet containing FM: CSJ 2:1 without the addition of enzymes. The highest TAC, GSH and SOD values were recorded by fish fed diet containing FM: CSJ 1:2 or 2:2 with 0.5 g enzymes mixture kg−1 diet. Fish fed diets comprising various ratios of FM: CSJ with 0.5 g enzymes mixture kg−1 diet had the lowest (P < 0.05) MDA value. In conclusion, using mixture of enzymes (protease, pepsin, trypsin, xylanase and amylase) at 0.5 g kg−1 in combination with a high blend of CSJ instead of FM; 2:2 improved the growth performance, digestibility, digestive enzyme, intestinal morphology, blood indices, and immune response of Nile tilapia.

Variation of dietary protein/lipid levels used in postlarvae of freshwater prawn Macrobrachium rosenbergii cultured in a biofloc system

A 70-day experimental trial was performed to evaluate the contribution of biofloc to the nutrition of Macrobrachium rosenbergii 15 days old postlarvae (PL) (average 82.00 ± 19.71 mg) fed different crude protein (P) and lipids (L) levels in zero-water exchange culture tanks. Six biofloc treatments (BFT) as experimental diets with 15, 20, or 25% P levels and 5 or 8% L levels were managed: BFT-15/5; BFT-15/8; BFT-20/5; BFT-20/8; BFT-25/5; BFT-25/8, and a clear-water control without biofloc fed with 25% P and 8% L (CW-25/8). The experiment was done in triplicate in 21-60 L plastic tanks containing 10 prawns tank-1. At the end of the experiment, survival of prawns was above 66%, with no significant differences among experimental groups (P &gt; 0.05). The best growth performance was observed in the experimental prawns maintained in BFT-20/5, BFT-20/8, BF-25/5, and BFT-25/8 compared to the control (P &lt; 0.001). The feed conversion rate of the prawns in BFT-20/5 was significantly lower than that in control (P &lt; 0.001); the best P efficiency ratio and productive P value were observed in all BFT compared to control prawns (P &lt; 0.001). Results showed that it is feasible to use low concentrations of P (20%) and L (5%) in diets to grow giant freshwater prawn PL in a biofloc system. Results also demonstrated that biofloc contributes to the P and L requirements of cultured freshwater prawn PL, as indicated by improved feed utilization, P retention, and growth performance.

Quality analysis of commercially available miso produced in wooden barrel and fiber reinforced plastic tank

最近, 味噌の製造工程で発酵・熟成工程に使用される容器は, 従来の木製の桶から繊維強化プラスチック (FRP) や金属製のタンクに代わってきている. そのため, 仕込み容器の違いが味噌に与える影響を明らかにすることを目的に, 木桶およびFRP製の仕込み容器で同一原材料と原料処理および配合条件で仕込み, 製造された米味噌を用いて解析を行った. その結果, 木桶味噌とFRP味噌との差異は, 栄養成分, 有機酸および遊離アミノ酸量において若干認められたが, 味覚に関しては大きな影響を与えないことが示された. しかしながら, 香気成分では両者に大きな差が認められ, 木桶で製造された味噌の方が香気成分含量および種類ともに多かった. この要因として, 木桶味噌とFRP味噌の菌叢分布差異が影響していると示唆された.