Weight Specific Growth Rate Research Articles

Effects of Different Dietary Organic Acids on the Survival, Growth, and Hepatopancreatic Histopathology of the Blue Swimmer CrabPortunus pelagicus

Organic acids are receiving increasing attention as a potential means to improve the growth as well as nutrient utilization of aquatic animals. A 20-day experiment was conducted to compare the effects of different dietary organic acid salts that included sodium acetate, sodium citrate, sodium butyrate, or sodium propionate at 2%, on the survival, growth, and hepatopancreatic histopathology of blue swimmer crab Portunus pelagicus early juveniles. All diets were isonitrogenous and were provided to apparent satiation twice daily. Crabs were kept individually within plastic containers, and there were 45 replicate crabs for each treatment. Results showed that, by the third molt, all the tested dietary organic acids significantly (P < 0.05) accelerated the molting (7.16–8.65 days) of the crabs compared with those in the control treatment (10.03 days). The specific growth rate (SGR) for width and length as well as the final dry weights were significantly higher (P < 0.05) in all the organic acid treatments, while SGR for weight was significantly higher (P < 0.05) in the sodium acetate and sodium propionate treatments, compared with the control. Hepatopancreatic histopathology revealed no structural differences in all treatments or staining intensity for glycogen. To our knowledge, this is the first reported study showing improvements to the survival and growth of crabs fed with inclusions of dietary organic acids.

Influence of Lactobacillus plantarum supplemented diet on growth response, gut morphometry and microbial profile in gut of Clarias gariepinus fingerlings

Objective: To evaluate the influence of dietary inclusions of Lactobacillus plantarum (L. plantarum) on growth response, gut morphometry and intestinal microbial profile of Clarias gariepinus (C. gariepinus) fingerlings was carried out using a total of 150 C. gariepinus fingerlings (2.35 ± 0.48 g/fish) by selecting at random into five treatments groups of 10 fish in 3 three replicates each. Methods: L. plantarum isolated from corn slurry was cultured using standard measures. Five isonitrogenous diets were prepared at 35% crude protein (T0, T1, T2, T3 and T4) with L. plantarum at inclusion rate of 0.0%, 0.5%, 1.0%, 1.5% and 2.0% respectively. The fish were fed at 5% body weight per day for 12 weeks twice daily. Results: T4 recorded the highest mean weight gain and specific growth rate while the lowest was obtained in T1. T4 (1.97) when compared with other treatments had marginally lower feed conversion ratio. Absorptive area was most significantly higher in T3 and T4 group when compared to the control (T0) and other lower dietary probiotic inclusion groups. Cryptal depth was highest in T4 with significant difference which also gave the maximum enterobacteriaceae count while T0 recorded the least count. Conclusions: From these indications, L. plantarum fortified diets may enhance the growth of cultured C. gariepinus fingerlings at 2.0% inclusion rate as it was observed to improve body weight gain, feed conversion ratio with increment in the absorptive area and the microbial count in the gut.

English

The growth performance of Clarias gariepinus fed with different dietary levels of processed cassava leaves and their nutrient utilized were studied for a period of 24 weeks. One hundred and forty four experimental Catfish (Clarias gariepinus) with 0.75±0.20 g mean weight and 3.9±0.31 cm mean total length were collected from Aqua-fish Consult, Awka, Anambra State, Nigeria. Eighteen rectangular plastic tanks were used for this study. Green cassava leaves (Manihot esculenta) were collected from a farm in Uda, Igbo-Eze North of Enugu State. The leaves were soaked for 36 h and sun-dried for one week to reduce the presence of cyanogenic glycosides. The dried leaves were ground into fine powder and analyzed for proximate composition. The experimental design used was Complete Randomized Block Design (CRBD) consisting of 18 treatments. Triplicate culture tanks in treated (L25-L100), and control groups (L0 and Ac) were stocked with eight fingerlings per square meter, respectively. The cost benefit of C. gariepinus fingerlings was estimated using weight gain and specific growth rate against management and construction cost. Weight gain, specific growth rate (SGR), feed efficiency (FE) and total length (TL) of catfish in different treatments were plotted against water chemistry parameters. This trail was conducted to access the possibility of replacing maize (Zea mays) with varying levels of whole cassava leaf meal in the diet of C. gariepinus catfish. Five isocaloric and isonitrogenous diets were formulated to contain 0, 25, 50, 75 and 100% cassava leaves to replace equal weight of maize meal. Internationally made fish feed (coppens) was also used as a control feed. All the diets were fed to catfish (C. gariepinus) fingerlings in replicate for 24 weeks. The results revealed that optimum requirement of cassava leaves level in the formulation of practical diets for improved growth of C. gariepinus was 25%. Key words: Growth performance, nutrient utilization, Clarias gariepinu, cassava leaves.

Effect of Salinity at Different Temperature Regimes on Growth ofCyprinus carpio(Linn.) Fingerlings

The present study was undertaken to determine the effects of five different salinities (0 ppt, 1.5 ppt, 3 ppt, 6 ppt and 12 ppt) on growth of common carp for 60 days at three different temperature regimes. The experiment was conducted in aquaria of 38 litres capacity fitted with complete aeration and filtration system, with 10 fishes in each, at air temperature ranges from 31.0°C-37.5°C (high), 23.0°C-31.0°C (mild) and 13.5°C-19.0°C (low) in triplicate. Growth in terms of average daily gain (ADG), net weight gain (NWG) and specific growth rate (SGR) were estimated on weekly basis. The fingerlings adapted well to the saline environment upto 6 ppt but 100% mortality was observed in 12 ppt at high and mild temperature regimes while 50% survival was recorded at low temperature. The decreasing trend of ADG, NWG and SGR were observed in fingerlings from 0 to 12 ppt salinity. Maximum ADG was reported in 0 ppt salinity followed by 1.5 ppt, 3 ppt, 6 ppt and 12ppt. At all the temperature regimes, as salinity increases the NWG of carp fingerlings similarly decreased like ADG. The highest SGR was recorded in 0 ppt salinity and followed by 1.5 ppt>3 ppt>6 ppt at mild temperature. The highest SGR (1.70±0.01%) was detected on 15th day at 0 ppt while the lowest SGR (0.44±0.04%) was reported on 60th day in 6 ppt salinity at mild temperature. The differences were statistically significant (p≤0.05) among salinities. The present findings demonstrate that environmental salinity affects the growth of carp fingerlings, with maximum growth in freshwater and declined with ascending levels of salinities at different temperature regimes upto 6 ppt salinity.

Effect of different rearing systems on the growth and survival of Gold fish (Carassius auratus)

The study was conducted to compare the effect of three different fry rearing systems such as: hapa, cistern and pond on the growth and survival of goldfish (Carassius auratus ) fry. A total of 645 fry (mean initial weight: 0.0071 mg) were randomly distributed in the three treatments (systems) each having three replications. The stocking density was same in all the treatments with respect to the water volume of the systems which was 10 fry/hapa, 125 fry/cistern and 80 fry/pond. The trial lasted for 40 days. The water quality parameters were favorable in all the treatments during the period of the study. The growth and survival of goldfish fry varied among the systems. Highest average weight gain and specific growth rate (SGR) were observed in pond followed by hapa and cistern. On the other hand, survival rate was highest in cistern followed by hapa and pond. It can be concluded from the study that the pond was the best system in terms of growth rate and cistern was the best system for survival of gold fish fry.Res. Agric., Livest. Fish.2(2): 301-306, August 2015

English

Several studies had been conducted on the nutritional requirements of African catfish, Clarias gariepinus. Nevertheless, currently there is a gap about the gross composition of feed ingredients required for formulation of commercial feeds. The aims of this feeding trial were to investigate whether fish fed four different commercial feeds have a significant growth rate and nutrient utilization. A total of 120 fish samples were stocked for a triplicate feeding trial (10 fish for each replication) in 4 separated tanks with 4 different feeds: Euro, Melick, Coppens and Durante (T1), (T2), (T3) and (T4) respectively. During all the trial, the water quality and growth parameters were determined according to standard methods and no significant differences were found among the water quality parameters determined. The mean weight gain (MWG) and specific growth rate of T3 were significantly higher than those of other treatments. Statistics showed that protein efficiency ratio (PER) of T3 was significantly higher than other treatments. Contrary to the above trend, the feed conversion ratio (FCR) of T2 was significantly higher than other treatments. According to the results of this study, fish fed with Coppens feed showed a significant growth rate and nutrient utilization. Key words: Feeding trial, treatments, growth, nutrient utilization, commercial feeds.

Fish Silage as Replacement of Fishmeal in Red Tilapia Feeds

We estimated the effect on growth and nutrient efficiency of replacing fishmeal with silage incorporated with rice bran in diets for fingerling red tilapia (Oreochromis mossambicus × Oreochromis niloticus × Oreochromis aureus) over 12 weeks. Isonitrogenous (300 g kg−1 protein dry matter basis) and isoenergetic (4450 Kcal gross energy kg−1) feed formulations with increasing levels of tilapia silage as a replacement for fishmeal were prepared: Diet 1 with no silage (0 g Kg−1), Diet 2 (250 g Kg−1), Diet 3 (500 g Kg−1), and Diet 4 (750 g Kg−1). Feed intake was similar among Diets 1, 2, and 3, while Diet 4 had a significantly lower intake. There was no significant difference (P > 0.05) in weight gain or specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER), among fish fed Diets 1, 2, and 3. Fish fed with Diet 4 had significantly lower weight gain; SGR and PER and significantly higher FCR. Organoleptic properties of the fish were not affected by the diets. The results of this study indicate that less expensive dried fish silage with rice bran is an alternative protein source for tilapia feed up to 50% of fishmeal replacement.

Dwarfism of blue mussels in the low saline Baltic Sea—growth to the lower salinity limit

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 517:181-192 (2014) - DOI: https://doi.org/10.3354/meps11011 Dwarfism of blue mussels in the low saline Baltic Sea—growth to the lower salinity limit Hans Ulrik Riisgård1,*, Poul S. Larsen2, Raisa Turja3, Kim Lundgreen1 1Marine Biological Research Centre (University of Southern Denmark), Hindsholmvej 11, 5300 Kerteminde, Denmark 2DTU Mechanical Engineering, Fluid Mechanics, Technical University of Denmark, Building 403, 2800 Kgs. Lyngby, Denmark 3Finnish Environmental Institute, Marine Research Centre, PO Box 140, 00251 Helsinki, Finland *Corresponding author: hur@biology.sdu.dk ABSTRACT: Mussels within the Baltic Mytilus edulis × M. trossulus hybrid zone have adapted to the low salinities in the Baltic Sea which, however, results in slow-growing dwarfed mussels. To get a better understanding of the nature of dwarfism, we studied the ability of M. trossulus to feed and grow at low salinity (7 psu) compared with its performance at relatively high-salinity (20 psu) in controlled laboratory experiments, supplemented with field (Great Belt) growth experiments with M. trossulus and M. edulis in net-bags. Subsequently, the growth of M. trossulus transplanted in cages to various localities in the northern Baltic Sea was used to evaluate the effect of very low salinities, down to 3.4 psu. The laboratory feeding experiments with M. trossulus at 7 psu showed that the growth in shell length was negligible, whereas the body dry weight nearly doubled during the 15 d experiment, with a weight-specific growth rate of 3.7% d-1. The same parameters measured at 20 psu showed a pronounced growth in both shell length and body dry weight, with a weight-specific growth rate of 2.2% d-1. The growth rates of M. trossulus and M. edulis in suspended net-bags in the Great Belt (22 psu) were similar: 5.6 and 6.8% d-1, respectively. M. trossulus in cage experiments had positive growth rates at locations with salinities above 4.5 psu, up to 2.60% d-1, but negligible increase in the shell length, and at sites with salinities below about 4.5 psu, the somatic growth was negative, around -0.3% d-1, which indicates valve closure and respiratory weight loss. A trend line in a plot of all available growth data for both mussel species as a function of salinity indicates that the growth of mussels is steadily hampered by reduced salinities from 30 psu down to about 10 psu, below which the growth is rapidly reduced to become negative below 4.5 psu. We suggest that reduced ability to produce shell material at extremely low salinity may explain dwarfism of mussels in the Baltic Sea. Reduced bio-calcification at low salinity, however, may impede shell growth, but not somatic growth, and this may at first result in an increased condition index, as seen in the benthic Baltic Sea mussels transferred to cages suspended in the water column. KEY WORDS: Mytilus edulis · Mytilus trossulus · Filtration rate · Specific growth rate · Adaptation · Effect of salinity · Condition index · Bio Energetic Growth (BEG) model Full text in pdf format PreviousNextCite this article as: Riisgård HU, Larsen PS, Turja R, Lundgreen K (2014) Dwarfism of blue mussels in the low saline Baltic Sea—growth to the lower salinity limit. Mar Ecol Prog Ser 517:181-192. https://doi.org/10.3354/meps11011 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 517. Online publication date: December 15, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Responses of the killifish (Aphanius dispar) to long-term exposure to elevated temperatures: growth, survival and microstructure of gill and heart tissues

Some fish species, such as killifish, that normally inhabit temperate water environments are also found in extreme thermal environments such as thermal springs. The extent of the adaptations involved is not known. In the present laboratory study, we exposed killifish (Aphanius dispar) acclimated to a normal thermal environment to elevated temperatures (37–40 °C) in which related killifish species live permanently. Our objective was to determine whether there is evidence that killifish have heat-shock characteristics that make permanent adaptation likely. The fish was exposed to this temperature for a period of 44 days and then compared with control fish kept at their normal temperature (24 °C) with respect to growth, survival and histopathology of gill and heart tissues. At the end of the experimental time, the percentage of body weight gain and specific growth rate were significantly lower in fish kept in thermal stress compared with the control group. Feed conversion ratio (FCR) was also significantly affected by water temperature, so that during thermal stress the values of FCR were negative. Fish condition (Condition factor: CF) did not differ significantly between both groups at the end of the experiment. On days 11 and 33, however, CF was significantly lower in the thermal stress group. The gill showed blood congestion in primary lamellae and shortened secondary lamellae in fish kept at 37–40 °C. No specific alterations were found in the cardiac tissue of fish kept in thermal stress conditions. Under thermal stress, 40% of fish survived until the end of the experiment. A preliminary conclusion drawn from this work is that A. dispar, which lives at normal temperatures, shows evidence of adaptability to elevated temperatures that could be a factor in the ability of killifish to adapt permanently over time to thermal environment.

Distribution, hatch-date, growth, and mortality of larval Benthosema pterotum (Pisces: Myctophidae) in the shelf region of the East China Sea

We examined the distribution, hatch-date, growth, and mortality of larval Benthosema pterotum, a dominant pseudoceanic myctophid in the shelf region of the East China Sea, during early autumn when the main spawning has been predicted. This species is a key species in the food web of this area. Larvae were abundant in the area south of Cheju Island (60–80 m depth), corresponding with the adult habitat. Occurrence of the larvae was restricted to the onshore side of the shelf-break salinity front, indicating that this front acted as a barrier restricting the offshore dispersion of the larvae. In the area where the larvae occurred, a cyclonic eddy is formed, which is considered to limit the dispersal of the larvae, enabling them to recruit into the area of adult habitat. Modes of hatch-date appeared from late August to early September and from mid to late September, suggesting that large-scale spawning events occurred at least twice during the spawning season. Since the modes coincided with the new moon period, B. pterotum is suggested to spawn periodically once a month around the new moon, resulting in efficient mating and fertilization. Mean absolute growth rate (0.26 mm d−1) and weight-specific growth rate (18.8% of dry body weight d−1) were higher than previously reported values of other subtropical–tropical myctophids, which would be related to the high food availability in the study area. Daily instantaneous mortality coefficient during the first two weeks after hatching was estimated to be 0.28 d−1 (equivalent to 24.7% mortality d−1).

The use of vertical constructed wetland and ultrasound in aquaponic systems

Treatment performance, fish production, crop plant biomass production, water consumption, and water use efficiency of a pilot aquaponic system for small-scale land-based cyprinid fish farms were evaluated. The system consisted of a 36 m(3) Pond A with an initial carp load of 0.6 kg/m(3); of a treatment chain with a lamellar settler, a roughing filter, a vertical constructed wetland filled with expanded clay and planted with tomatoes; and of a low power ultrasound unit installed in the corner of the pond. The average circulation of the water in the system was 1.2 times per day. Pond A was compared with Pond B of the same dimensions and fish load but with no treatment chain or ultrasound. The treatment chain was efficient in mass removal of total suspended solids , biochemical oxygen demand, chemical oxygen demand, NH4-N, total nitrogen, and total phosphorous (57, 49, 35, 42, 31, and 25 %, respectively). Negative removal of NO3-N, NO2-N, and PO4-P indicated the need for the introduction of additional hydroponic beds in the system. Pond A had markedly lower nutrient concentrations compared with Pond B. Fish body weight increase and specific growth rate in Pond A were higher than in Pond B (102.6 %, 72.1 %; 0.19 %/day, 0.14 %/day, respectively) indicating better rearing conditions in Pond A. Tomato biomass production was high. Water use efficiency was higher in Pond A compared with Pond B (0.31 kg of produced fish/m(3) inflow water and 0.22 kg of produced fish/m(3) inflow water, respectively). The presented aquaponic system could be useful for semi-natural fish farming with fish loads up to 2 kg/m(3).

Ascorbic acid requirement and histopathological changes due to its deficiency in juvenile spotted rose snapper Lutjanus guttatus (Steindachner, 1869)

A 13-week feeding trial was conducted to determine the optimal dietary ascorbic acid (AA) requirement of juvenile spotted rose snapper (Lutjanus guttatus). Six experimental diets containing 0, 7, 19, 29, 62 and 250 mg AA equivalent kg−1 diet, supplied as l-ascorbyl-2-polyphosphate designated as VC0, VC7, VC19, VC29, VC62 and VC250, were fed ad libitum to triplicate groups of 20 juveniles [initial weight (IW) of 8 ± 1.85 g]. Nutrient deficiency resulting in fin erosion, dark skin, desquamation and erratic swimming was observed after 8 weeks in fish fed diets from 0 to 29 mg AA kg−1. Fish that were fed all diets showed gill, kidney and brain alterations. The degree of tissue change values indicates that increasing vitamin C (VC) levels reduces these alterations. Fish fed diets VC29, VC62 and VC 250 showed a significantly higher growth rate in comparison with those fed the diets VC0, VC7 and VC17 (P > 0.05). The dietary requirement of VC in L. guttatus was estimated to be 29 mg kg−1 of AA based on weight gain and specific growth rate, but more than 250 mg kg−1 of AA is required to eliminate clinical signs and histopathological lesions.

Enhancement of nitrogen and phosphorus removal from eutrophic water by economic plant annual ryegrass (Lolium multiflorum) with ion implantation.

Severe eutrophication of surface water has been a major problem of increasing environmental concern worldwide. In the present study, economic plant annual ryegrass (Lolium multiflorum) was grown in floating mats as an economic plant-based treatment system to evaluate its potential after ion implantation for removing nutrients in simulated eutrophic water. The specific weight growth rate of L. multiflorum with ion implantation was significantly greater than that of the control, and the peroxidase, nitrate reductase, and acid phosphatase activities of the irradiated L. multiflorum were found to be greater than those plants without ion implantation. Higher total nitrogen (TN) and total phosphorus (TP) removal efficiencies were obtained for the L. multiflorum irradiated with 25 keV 5.2 × 10(16) N(+) ions/cm(2) and 30 keV 4.16 × 10(16) N(+) ions/cm(2), respectively (p < 0.05). Furthermore, the nitrogen and phosphorus contents in the plant biomass with ion implantation were also greater than those in the control and were positively correlated with TN and TP supplied. L. multiflorum itself was directly responsible for 39-49 and 47-58 % of the overall N and P removal in the experiment, respectively. The research results suggested that ion implantation could become a promising approach for increasing phytoremediation efficiency of nutrients from eutrophic water by L. multiflorum.

Production effect of different commercial feeds on juvenile tench (Tinca tinca L.) under the intensive rearing conditions

Feeding experiment with juvenile tench was focused on evaluation of production effect of three different commercial feeds with differentiated level energy and protein (Karpico Crumble Excellent Ex, Dan Ex 1352, Pro Aqua Brutfutter). In the 42-day experiment at 26 °C, commercial starters were fed intensively to tench of initially 18.92 mm mean total length and 69.41 mg individual mean body weight. Main monitored indices were – survival rate (%), individual body weight (mg) and specific weight growth rate (%.d−1). The best result was achieved with commercial starter Pro Aqua Brutfutter – mean individual body weight 483.38 mg, specific weight growth 4.44 %.d−1 and survival 99.1 %. Increasing level energy and protein increased production parameters of juvenile fish.

Comparative Assessment of Growth Performance and Economics of Production of Clarias gariepinus Fingerlings in Ponds and Tanks

An experiment was conducted to compare the growth and economics of producing Clarias gariepinus in ponds (6.4x5.4x1.5m 3 ) and tanks (2.5x1.1x1.2m 3 ) for 56days. Fingerlings of Clarias gariepinus (mean weight, 1.80g and body length, 4.40cm) were stocked at 250 and 50 fish separately into each pond and tank in duplicates. Fish were fed a commercial feed containing 45% crude protein at 5% body weight. It was divided into two halves and fed at 1000 and 1600hours daily. At final harvest, the total yield of fish was significantly greater (P 0.05) in mean weight gain (13.75+0.95g, 13.44+0.95g), condition factor (0.92 +0.03, 0.91+0.03) and feed conversion ratio (0.56+0.01, 0.51+0.01) between fingerlings stocked in pond and tank. Fish in pond had higher percentage weight gain and specific growth rate while survival rate ranged 74.11+0.54-88.80+0.54% in the culture media. Net profits obtained were N4300 (pond) and N2250 (tank). The benefit: cost ratio was higher for tank (1.38) than for pond (1.19). The pond environment appeared more productive while the tank was more economical with higher benefit in this study.

HETEROLOGOUS EXPRESSION OF Escherichia coli FRUCTOSE-1,6-BISPHOSPHATASE IN Corynebacterium glutamicum AND EVALUATING THE EFFECT ON CELL GROWTH AND L-LYSINE PRODUCTION

Fructose-1,6-bisphosphatase (FBPase), which is mainly used to supply NADPH, has an important role in increasing L-lysine production by Corynebacterium glutamicum. However, C. glutamicum FBPase is negatively regulated at the metabolic level. Strains that overexpressed Escherichia coli fructose-1,6-bisphosphatase in C. glutamicum were constructed, and the effects of heterologous FBPase on cell growth and L-lysine production during growth on glucose, fructose, and sucrose were evaluated. The heterologous fructose-1,6-bisphosphatase is insensitive to fructose 1-phosphate and fructose 2,6-bisphosphate, whereas the homologous fructose-1,6-bisphosphatase is inhibited by fructose 1-phosphate and fructose 2,6-bisphosphate. The relative enzyme activity of heterologous fructose-1,6-bisphosphatase is 90.8% and 89.1% during supplement with 3 mM fructose 1-phosphate and fructose 2,6-bisphosphate, respectively. Phosphoenolpyruvate is an activator of heterologous fructose-1,6-bisphosphatase, whereas the homologous fructose-1,6-bisphosphatase is very sensitive to phosphoenolpyruvate. Overexpression of the heterologous fbp in wild-type C. glutamicum has no effect on L-lysine production, but fructose-1,6-bisphosphatase activities are increased 9- to 13-fold. Overexpression of the heterologous fructose-1,6-bisphosphatase increases L-lysine production in C. glutamicum lysC T311I by 57.3% on fructose, 48.7% on sucrose, and 43% on glucose. The dry cell weight (DCW) and maximal specific growth rate (μ) are increased by overexpression of heterologous fbp. A “funnel-cask” diagram is first proposed to explain the synergy between precursors supply and NADPH supply. These results lay a definite theoretical foundation for breeding high L-lysine producers via molecular target.

Effect of Plant Based Feed Attractants on Growth ofCirrhinus mrigalaFingerlings

A 60-d experiment was conducted to study the efficacy of plant-based attractants in the feed of Cirrhinus mrigala fingerlings (av. weight 5.24±0.02g). The formulated feed contained mustard cake, soyabean meal, rice bran, vegetable oil, vitamin and mineral mixture with 1% feed attractants replacing rice bran. The different attractants used in feeds are: FA0 (Control), FA1 (Awbel, Cuscuta reflexa), FA2 (Kharboj, Cucumis melo), FA3 (Tambul, Zanthoxylum acanthopodium), FA4 (Chotokakla, Piper cubeba) and FA5 (Jayatri, Myristica fragrans). The net weight gain (g) was 1.05±0.15, 2.43±0.08, 1.45±0.05, 1.53±0.28, 1.50±0.02, 2.05±0.05, respectively in dietary groups Control to FA5. The growth study with different attractants revealed that the net weight gain and specific growth rate (SGR) were significantly (P 0.05) among the groups fed with different plant based feed attractants. Thus it may be concluded that out of the attractants tested in the present experiment, use of Awbel at 1% level (FA1) in the diet induced better performance in terms of growth and feed utilisation in mrigal fingerlings.

Dietary Effects of Ripe and Unripe Banana Peels on The Growth and Economy Of Production Of Juvenile Catfish (Clarias gariepinus Burchell, 1822)

Six diets were produced using graded levels of banana peels (5, 10 and 15% for both ripe (RBP) and unripe (UBP) banana peels) which were compared with the control diet (CTR) containing maize in the diet of C. gariepinus juveniles. Feeds were fed to triplicate groups of ten fish each to satiation thrice daily for ten weeks. There were significant differences (p0.05) in Mean Weight Gain (MWG) and Specific Growth Rate (SGR) across diets. The CTR had the highest MWG (58.40 ±5.27g) and SGR (1.877±0.09%) while the least values of MWG (25.03 ±1.85g) and SGR (1.106 ±0.05%) were recorded in Diet3 (15% UBP). The Feed conversion ratio, Protein efficiency ratio and Protein intake recorded significant differences (P0.05) etween the CTR and other diets. Similar results were recorded for Profit Index, Incidence of Cost and Economic Investment Cost Analysis. Likewise, analysis of fish organs recorded significant differences (P0.05) between the CTR and other diets. Though the CTR had the best growth performance, it had the least Profit Index (1.87) while Diet2 (10%RBP) had the highest Profit Index (3.11). Thus, plantain peel is a proftable alternative energy source for partial substitute of maize up to 10% RBP and UBP in diet of C. gariepinus.

Effects of NaCl and NaHCO3 on growth and gill microstructure in ju-venile &lt;I&gt;Barbus capito&lt;/I&gt;

We evaluated the effects of salinity and alkalinity on growth,feeding,and gill microstructure in juvenile Barbus capito.The fish were reared at salinity of 0(control group),2.0,4.0,6.1,7.8,10.0,or 11.9 for 60 d with temperature of 22-25℃.The body length,body weight,and specific growth rate(SGR) of juveniles were signifi-cantly lower in fish held at salinities 6.1 than in those held in salinity 6.1(P0.05).The maximum final body weight was highest in the fish reared at 2.0.The specific growth rate of weight(SGRW) and feed conversion effi-ciency(FCE) were highest in fish held at 4.0 and lowest in fish held at 11.9.Our results suggest the optimal salin-ity for growth is 1.88,whereas exposure to levels ≥7.8 results in negative effects.Fish were also reared at 10.00,15.83,25.10,39.80,and 63.12 mmol/L NaHCO3.The body weight,length,and the SGR of juveniles reared in water with 25.10 mmol/L NaHCO3were significantly lower than in the remaining groups(P0.05).The largest final body weight,body length,SGR,SGRW,and FCE were in fish reared at 15.83 mmol/L NaHCO3.The fish reared at 63.12 mmol/L NaHCO3 had the lowest values for all indices.Rearing in water with NaHCO3 levels 39.80 mmol/L had negative effects and the optimal alkalinity for growth was 20.57 mmol/L.Observation of gill microstructure revealed hypertrophy in the chloride cells,and both hypertrophy and edema in the epithelial cells as salinity and alkalinity levels increased,thereby affecting the growth of the fish.In conclusion,the salinity should bebelow 6.1 or the alkalinity should be below 25.10 mmol/L in the Barbus capito larvae culture.

Application of fish gelatin as diet binder in diets for the common carp Cyprinus carpio L. fingerlings

Fish gelatin applied as an animal source binder and stabilizer in diets for the common carp Cyprinus carpio L. fingerlings in comparison with binder void diet. Experimental diets prepared from standard raw materials adding laboratory made fish gelatin at 1% as binder. Three types of gelatin applied (extracted from tilapia Tilapia zilli skins, common carp Cyprinus carpio L. gas bladder and barred needlefish Ablennes hians heads). Three diets containing each type of extracted gelatin were prepared to compare with gelatin void diet. Fish initial average weight 5.56 gm were fed at 5% body weight daily. Chemical and physical analyses performed on pellets thrown into water to feed fish as affected by added gelatin. The influences of gelatin monitored on pellet density, floating period, sinking velocity, water absorption rate and disintegrating rate as indicators for pellet quality and resistance into water. Feed intake by fish during research period studied also. Results showed that bladder gelatin diet gave the highest weight increase in comparison with other diets which reached 15.6gm. Physical measurements demonstrated that the highest density recorded in bladder gelatin diet (1.4 gm/cm 3 ) followed by head and skin gelatin diets (1.3 gm/cm 3 ) while the lowest density recorded in gelatin void diet (1.1 gm/cm 3 ). Floating time of 8.55 sec. and sinking velocity of 1.06 sec./cm recorded for bladder gelatin diet in comparison with 7.53, 7.31 and 5.30 sec. for floating time and 1.37, 1.43 and 2.47 sec./cm for sinking velocity of diets containing head , skin gelatin and control, respectively. Various treatment indicated impacts on growth where weight increase rated 10.26-15.6 g, specific growth rate 1.10-1.61 and relative growth rate 39.46-62.40 %. Bladder gelatin diet surpassed others in weight increase, specific and relative growth rates. Feed conversion ratios reached 3.156, 2.862, 3.597 and 4.306 for skin, bladder, head gelatin and control diets, respectively. As for feed intake, bladder gelatin treatment gave the highest values. Chemical composition did not affected by using binders.