Effect of monosodium glutamate dietary supplementation on some productive traits of common carp (Cyprinus carpio L.), cultivated in net cages

  1. G. Zhelyazkov*

 

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6014 Stara Zagora, Bulgaria

 

DOI: 10.15547/ast.2018.03.039

(Manuscript received 30 May 2018; accepted for publication 15 August 2018)

 

Abstract. The aim of the study was to determine the effect of a monosodium glutamate dietary supplementation on the survival rate, growth performance, feed conversion ratio and economic efficiency of common carp (Cyprinus carpio L.), cultivated in net cages. Two hundred carps were allotted into two experimental variants, each of them comprising two replications (Control groups – CG and CG1; Experimental groups – EG and EG1), with 50 fish in a group. The average initial live weight of fish from the control and experimental groups was 1141.62±79.62g and 1129.54±71.47g, respectively (P>0.05). The carps were cultivated in net cages with a size 3.0/3.0/2.0m. The fish were fed with extruded feed Aqua garant VITAL, a product of Garant-Tiernahrung Gesellschaft m.b.H. – Austria, with 6mm size of pellets. Monosodium glutamate in amount of 1% was added to the feed of carps from the experimental groups. The fish from the control groups received no monosodium glutamate supplementation of the diet. The feed given to the fish was 2% of the total biomass. The trial period was 60 days, control catch at 30th day were done in order to study the influence of the monosodium glutamate supplementation on the weight gain and feed conversion ratio of the common carp, cultivated in net cages. The initial (1st day), control (30th day) and final (60th day) live weights (g) were determined by individual weighing. The final live weight of the fish from both replications of the experimental and the control groups was as follows: 1699.36±78.43g and 1597.27±74.66g, the differences were significant (P<0.001). The survival rate of carps from both control and experimental group replications was 100%. The average individual weight gain of fish from the two replications (supplemented with 1% monosodium glutamate) was 569.82±3.75g which was higher than that of controls by 20.04%, the differences were significant (P<0.001). At the end of the trial, the analysis of consumed feed amount showed that feed conversion ratio in the group supplemented with 1% monosodium glutamate was 1.76±0.12, i.e. by 25.57% lower than that of control carps (P<0.001). The economic efficiency in the experimental groups exhibited better economic conversion ratio (0.936), by 22.65% lower than that of the non-supplemented groups.

Effect of nutmeg extract supplementation on some productive traits and economic efficiency of common carp (Cyprinus carpio L.) cultivated in recirculation system

  1. Zhelyazkov*, S. Stoyanova, I. Sirakov, K. Velichkova, Y. Staykov

 

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University,

6000 Stara Zagora, Bulgaria

(Manuscript received 21 December 2017; accepted for publication 16 February 2018)

 

Abstract. The aim of the present study was to evaluate the effect of a dietary nutmeg extract supplement on the survival rate, growth performance, feed conversion ratio and economic efficiency of common carp (Cyprinus carpio L.) reared in a recirculation system. Thirty-two carps were allotted into two experimental variants, each of them comprising two replications with 8 fish in a group. The average initial live weight of carps from the control group (CG) and experimental group (EG) was 866.56±113.99g and 868.50±111.18g, respectively (P>0.05). Fish were reared in concrete tanks with efficient volume of 0.8m3, elements of the recirculation system. They were fed pelleted carp feed with 25% crude protein produced by “Top mix” company, with pellet size of 6mm. The feed of fish from the EG was supplemented with 1% powdered nutmeg extract after lubricating the pellets with 5ml sunflower oil per 100g feed. Control carps received the same amount of sunflower oil-lubricated feed. The daily ration of fish from both replications was 1.8% of their live weight. The experiment duration was 45 days. The initial and final live weights were determined by individual weighing. By the end of the experiment, there was a tendency towards statistically insignificant higher average live weight in fish supplemented with 1% nutmeg extract – 986.44±125.91g vs 964.94±92.04g in non-supplemented controls (P>0.05). The survival rate of carps from both control and experimental group replications was 100%. The average individual weight gain of carps from the two EG replications (supplemented with 1% nutmeg extract) was 117.94±31.24g which was higher than that of controls by 16.58% but the differences were not statistically significant (P>0.05). At the end of the trial, the analysis of consumed feed amount showed that feed conversion ratio in the group supplemented with 1% nutmeg extract was 3.05±0.78, i.e. by 23.28% lower than that of control carps (P>0.05). The group that received 1% nutmeg extract exhibited better economic conversion ratio (2.71), by 4.06% lower than that of the non-supplemented group.

Effect of linseed and sunflower oils in the diet on the growth parameters in rainbow trout (Oncorhynchus mykiss W.) cultivated in a recirculating system

G. Zheliazkov*

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The aim of this study was to determine the influence of linseed and sunflower oils in the diet on the survival rate, weight gain and the feed conversion ratio in rainbow trout, reared in a recirculating system. The fish of the three groups were raised in concrete tanks with effective capacity of 0.8 m3, which were part of the recirculating system. Rainbow trout received extruded feed (6 mm pellets), produced by “Aqua garant”. The feed of the fish from the experimental group (EL) was supplemented with 5% linseed oil, while that of the trout of the group (ES) – 5% sunflower oil. The diet of the fish of the control group (C) did not contain any of the above mentioned oils. The duration of the trial was 60 days. In order to study the effect of linseed and sunflower oils in the diet on the weight gain of the fish, control catches were carried out at 15 days’ interval. The live weight (g) and linear growth (mm) of the control catches were determined as the fish were individually weighed and measured. The final live weights of the trout in the experimental groups as well as that in the control were as follows: EL – 334.79±67.52g, ES – 329.39±70.31 g and C – 323.58±67.77 g. The values of this parameter in EL were higher than those of fish from ES and the control group by 1.64% and 3.47%, respectively, but the differences were not significant (P>0.05). This trend persisted also for the linear measurements – in the trout of EL they were the highest. The fish of EL displayed the lowest feed consumption. This trait had lower values than the ones of the trout of ES and the control group by 2.84% and 5%, respectively, though the differences were not significant (P>0.05). The survival rate of the fish from the groups did not differ substantially.

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Effect of linseed and sunflower oil supplementation in the diet on the growth performance in carp (Cyprinus carpio L.), cultivated in a recirculating system

Abstract. The aim of this study was to determine the influence of linseed and sunflower oil supplementation on the survival rate, weight gain and feed conversion ratio in carp (CyprinuscarpioL.), raised inarecirculating system. The fish in the experiment were reared in concrete tanks that were part of the recirculating system and had a capacity of 0.8 m3. The carps received extruded pellets (6 mm) obtained by “Aqua garant”. For a period of 60 days the feed of the fish of the experimental group (EL) was supplemented with 5 % linseed oil, while the carps of the group (ES) received additionally 5 % sunflower oil with the diet. The fish of the control group (C) received feed without any of the above mentioned vegetable oils. The weight gain of the carps was controlled at 15-days intervals. The live weight (g) and the linear growth (mm) were determined as the fish were weighed and measured individually. The final live weight of the carps of the experimental and control groups was as follows: EL–871.45±240.39 g, ES–849.00±223.22 g and C–819.55±269.91 g. The value of this parameter in the fish of EL groups was by 2.58% and 5.96% higher than those of the individuals of ES and C groups, respectively, but the differences were not significant (P>0.05). This tendency was similar for the linear measurements, as in the carps receiving linseed oil they were the highest. The EL group displayed the lowest feed consumption. The value of this parameter was lower than those of the ES and C groups by 13.90% and 25.74%, respectively. The differences were significant between the control group and the carps supplemented with linseed oil (P<0.05). The survival rate in the fish of the three groups did not differ significantly.

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