Browsing by Subject "Karpfen"

Now showing 1 - 4 of 4

Development of supplemental diets for carp in Vietnamese upland ponds based on locally available resources
(2010) Nguyen Ngoc, Tuan; Focken, Ulfert
Cyprinids play very important role in aquaculture, especially in Asia and Pacific regions. Vietnam is not an exception. Although aquaculture in Vietnam increased dramatically recently, its high value products such as catfish, tiger prawn seem to be unaffordable for the people in rural areas, especially for the mountainous ethnic minority in the North who are more independent to herbivorous and omnivorous fish such as grass carp, Indians carp, and common carp. Yen Chau is a district of Cyprinids play very important role in aquaculture, especially in Asia and Pacific regions. Vietnam is not an exception. Although aquaculture in Vietnam increased dramatically recently, its high value products such as catfish, tiger prawn seem to be unaffordable for the people in rural areas, especially for the Son La province, located in mountainous region in North-Western Vietnam. In this district, Black Thai ethnic minority accounts for approximately 54% population. Besides producing huge amount of grain and tuber crop such as maize and cassava for selling, aquaculture in a small poly-culture pond system is also a very typical activity which supplies an important nutritional source for human consumption and income generation as well. However, even though most of farmers in Yen Chau own at least one pond each, the demand on the local market cannot be covered (Steinbronn, 2009). Recently, unknown diseases causing high mortalities could be the reason of the decrease of grass carp production. To avoid risk from losing grass carp, farmers are tending to change the composition of the fish species stocked in favour of e.g. common carp and mud carp without having an appropriate feed base for these species. So far, no high quality feed was applied into the pond system. Therefore, the study entitled ?Development of supplemental diets for carp in Vietnamese upland ponds based on locally available resources? was conducted to not only contribute to an improvement of income and food security in the region but also meet the appeal of improvement of scientific knowledge on cyprinids which is inadequate with their great contribution. In the study, most of the possible feed ingredients were collected and analyzed for nutritive and non-nutritive values. Based on the results of the analysis a number of diets were formulated for 30% of CP and 10% of CL then tested by common carp. In total, four experiments were designed. The first was conducted in laboratory in which common carp were fed by local pelleted feed with 25, 50, and 75% protein derived from local ingredients. Results of this trial were confirmed by the trial 2 which was implemented under pond condition at Hanoi University of Agriculture. Trial 3 was conducted to compare different protein (full fat soybean meal and soybean cake) and carbohydrate sources (maize and cassava powder). Furthermore, sweet potato leaves were preliminarily investigated in fish feed inclusion. The last trial, trial 4, was carried out to evaluate the use of earthworm for common carp. Trial 1, 3 and 4 were designed for a recirculation system in which five common carp were stocked in each aquarium of 40 l with 3 replicates. Water flow through the aquaria was maintained at 6-7 litters per minute. Water temperature, DO and pH were kept at 25-27°C, above 4 mg/l and around 7.0-8.0, respectively. The photoperiod was set up at 12 hrs light:12 hrs dark. Fish were fed daily five times metabolic body mass requirement for eight weeks. The trial 2 consisted of four feeding groups (3 test diets and 1 control), each having three replicates. In each net, 45 common carp were stocked, Fish were fed three times per day (8h, 12h, and 16h) at a feeding rate of 5 times of maintenance requirement manually. Feed amount was adjusted every ten days after taking the weight of fish. The total trial lasted for 2 months. Analytical results show that all of local materials have good nutritive values, similar or better that those in other regions. Besides, fish meal and many other ingredients can be used as source of protein such as full fat soybean meal, soybean cake, meat meal, as well as earthworm powder. This earthworms Perionyx excavatus show a suitable quality for fish feed, high protein (71% of DM) and amino acids in comparison with many conventional protein sources, including fish meal. Replacement of 70% of protein (~ 20% of DM) by earthworms can significantly improve growth of fish. However, it is still unclear in full replacement fish meal by this material. Using maize and cassava in Yen Chau is also feasible because these materials not only are cheap but also are the most available. Among all plant materials, full fat soybean seems to be the best ingredient with high protein and lipid content. In contrast, fish seem to be deficient of nutrient by feeding sweet potato leaf inclusion diets. In conclusion, except for sweet potato, all of local ingredients can be used for fish feed formulation. The local feeds were well digested, utilized by omnivorous common carp. Despite local feed ingredients did not give the best growth of fish, they gave the best results in term of economic return. Local ingredient feed gave the lowest cost of feed as well as the lowest cost of fresh fish produced. The field trial fish performance seems to be better than in the laboratory due to receiving certain amount of natural food. Thus, fish utilize feed more efficiently resulted in reduction of feed conversion ratio as well as cost of feed per unit of fish produced. Transfer knowledge about low-cost feed to the local farmer together with basal techniques of producing, storing, and effective using fish feed is an important issue which could help farmers to improve production of fish in the region as well as contribute to poverty alleviation in the rural areas in Vietnam.
Effects of low dietary levels of saponins on two common culture fish - common carp (Cyprinus carpio L.) and Nile tilapia (Oreochromis niloticus (L.))
(2001) Francis, George; Becker, Klaus
Saponins are a group of compounds present in many wild plants and cultivated crops and are commonly found in traditional medicinal preparations. Feeding experiments using saponin-supplemented (commercial Quillaja saponin) feeds were conducted in two commonly cultured fish species, namely common carp (Cyprinus carpio L.) and tilapia (Oreochromis niloticus (L.)). Quillaja saponins (QS) at dietary levels of 150 mg kg-1 and 300 mg kg-1 significantly increased body weight gain in common carp and Nile tilapia compared to controls. When fed to tilapia fry QS (700 mg kg-1) altered the normal 1:1 sex ratio. In separate, in vitro measurements it was found that QS stimulated the release of leutinising hormone (LH) from cultured tilapia pituitary cells, but apparently this did not happen in vivo since serum levels of LH were not found to be elevated in the saponin fed fish. Dietary saponins were also found to affect serum and muscle cholesterol levels. Adult tilapia - but not tilapia fry - fed a dietary level of 300 mg kg-1 QS were found to have significantly higher muscle cholesterol levels than fish fed the control diet. In tilapia fry, the average serum cholesterol levels in males showed a steady increase from dietary QS levels of 0 to 700 mg kg-1, while no such trend existed among the females. Supplementation with 50 and 100 mg kg-1 of Yucca schidigera butanol extract (containing steroidal saponins) did not significantly promote the growth of carp despite showing initial promise. The purified haemolytic fraction of triterpenoid Gypsophila saponin extract (isolated using column chromatography) did not produce any toxic effects in carp at dietary levels up to 250 mg kg-1 in a preliminary feeding trial. A growth promoting effect was however evident at the very low level of about 5 mg kg-1 when the purified fraction was used. More research needs to be done to determine the mechanisms of action of QS and to test whether saponins from other sources have similar effects.
Evaluation of suitability of non-toxic and detoxified Jatropha curcas L. meal as feed for fingerling common carp, Cyprinus carpio L., with reference to phytase application
(2012) Richter, Nahid; Becker, Klaus
Jatropha curcas L. is a hardy plant which can thrive on marginal degraded lands. Jatropha seeds contain about 300-350g kg-1 oil, which is used as fuel or in transesterified form as a substitute for diesel; they also have considerable protein quality. However, Jatropha contains antinutrients such as lectins, trypsin inhibitors and phytic acids at high levels and in toxic varities phorbolesters cause detrimental effect. Common carp fed heat-treated non-toxic Jatropha meal (JM) has been shown to have higher weight gain and protein efficiency ratio than those fish fed untreated JM. However, these parameters were significantly lower in the aforementioned trial when compared to fish fed a fish meal (FM) based diet. Reduced growth performance in fish fed non-toxic JM might be attributable to the deficiency of some essential amino acids such as lysine, to high levels of phytic acids or the presence of antinutrients. These may indicate the need for additional processing of JM for common carp. This work was therefore conducted to test various ways of further improving the nutritional quality of JM to increase the levels of inclusion in diets for common carp. In the first experiment, four diets based on 50% replacement of FM with defatted non-toxic JM were formulated, one with no further JM treatment, the second with 80% aqueous ethanol extraction before diet formulation, the third supplemented with 1% L-lysine and the fourth with 500 FTU phytase (5000G, Natuphos). These were compared to a standard, FM based diet. The results showed that diets with 500 FTU/kg phytase or 1% L-lysine could maintain common carp?s growth performance at a level comparable to fish fed a FM diet. Fish fed diets containing JM and ethanol treated JM had significantly lower growth performance than the control. The addition of 1% L-lysine or 500 FTU phytase enhanced percent body weight gain, food conversion efficiency and specific growth rate to a level comparable to those of the control. Furthermore, the addition of 500 FTU phytase significantly increased whole body Mg, P and K to the levels of those fish fed Diet Control. When the level of JM replacement was increased from 50% to 75% while at the same time supplementing the diets with inorganic phosphorus (Experiment 2), however, a significant decrease in body weight gain of common carp was observed both with and without 500 FTU phytase. In a third experiment, the effect of JM diets with added phytase but without phosphorous supplementation was therefore investigated in more detail. At the end of the eight week trial, phytase supplementation had not affected body mass gain (BMG), food conversion ratio (FCR) and specific growth rate (SGR) of fish. However, whole body phosphorous (P), P gain and P retention were significantly improved in fish fed JM with phytase supplementation when this was compared to the fish fed JM without phytase. Moreover, fish fed JM diets indicated higher O2 consumption per gramme body mass gain than carp fed FM diets. Energy expenditure per gramme protein retained was significantly higher for fish fed JM with or without phytase addition, indicating that the utilisation of JM was associated with higher energy costs for the fish. In the final experiment, the nutritional quality of non-toxic JM was compared to that of the toxic variety once appropriate measures had been taken to detoxify the latter. FM was replaced with either of the two at 75% of total dietary protein, for each Jatropha variety once without further supplementation and once supplemented with 500 FTU phytase and 1% lysine. The results of this experiment indicated that there was no significant differences in final body mass (FBM), % BMG, feed intake (FI), FCR and specific growth rate (SGR) of fish fed diets Control and non-toxic, supplemented JM. However, fish fed diets based on detoxified or non-toxic, unsupplemented Jatropha showed significantly inferior growth parameters when compared to carp fed the first two diets (p<0.05). Whole body P was significantly higher in fish fed the Control and non-toxic JM diets (with/without phytase and lysine) than fish fed either of the two detoxified JM diets (p<0.05). The depressed growth performance in the group fed detoxified JM could imply that the detoxification process was not complete and traces of phorbolesters may still be present in the diets. This work has shown that, given proper treatment, JM can act as a suitable replacement for FM at high levels in diets for common carp. The results of this work suggest that phytase addition to enhance phosphorous availability and lysine supplementation to correct the essential amino acid imbalance are two factors that have significant effects in improving JM suitability for common carp.
Nutrient flow in improved upland aquaculture systems in Yen Chau, province Son La (Vietnam)
(2014) Pucher, Johannes Gregor; Focken, Ulfert
In South-East Asia, pond aquaculture plays an important role in the integrated agriculture aquaculture systems of small-scale farmers and contributes to their food security and income. In mountainous regions, aquaculture differs from aquaculture that is practiced in the lowland due to differences in climate and availability of feeds, fertilizers and water. In Northern Vietnam, the traditional aquaculture is a polyculture of 5-7 fish species. The macro-herbivorous grass carp (Ctenopharyngodon idella) is stocked as the main species. Common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), mrigal (Cirrhinus mrigala), mud carp (Cirrhinus molitorella) and Nile Tilapia (Oreochromis niloticus) are stocked as secondary species and are often insufficiently nourished by farm by-products. Manure is used by farmers as fertilizer for natural food resources. Ponds are managed as a constant water flow-through system. The inflowing water introduces soil particles eroded from the sloping fields of intensively cultured maize and cassava into the ponds, and cause high turbidity that limits both the primary and secondary production. The fish production of this system is low at about 1.5 ± 0.3 t ha-1 a-1 and is mainly limited by the poor quality of pond inputs, low availability of natural food resources, low oxygen production in the ponds and the occurrence of a species-specific disease that causes high mortality in grass carp. To improve the local fish production of small-scale farmers, changes in the traditional pond management were designed and tested in farmers’ ponds in the uplands of Northern Vietnam. These changes included the reduction of water flow through the ponds to reduce the introduction of eroded particles and reduce the turbidity. Chemical fertilizers were added to increase the productivity of natural food resources and encourage higher primary production. The disease-prone grass carp was replaced as the main species by common carp that command a similarly high price on the local markets. To feed the omnivorous common carp, supplemental pellet feeds based mainly on locally available resources were applied to the ponds. In a pond trial, the traditional and modified pond managements were compared for water quality parameters, availability of natural food resources, fish yields, nutrient utilisation efficiencies and monetary net benefit. In a 15N tracer experiment, the nitrogen dynamics in the natural food web in local ponds were compared under the two types of pond management. Acceptability of the modifications by local farmers was evaluated. In a net cage trial, the suitability of earthworm meal as a replacement for fishmeal in supplemental pellet feeds for common carp was tested. In another net cage trial, the effect of pesticide contaminated grass feeds on the feed intake and health condition of grass carp were tested. When compared with traditional pond management, the modified pond management was found to result in reduced water turbidity, deeper phototrophic zones, higher availability of natural food resources, higher primary production and higher fish yield. In addition, the small plankton benefited from the changes and allowed significantly higher growth rates of filter feeding fish. Common carp and grass carp had higher yields due to the changes. Under both types of pond management, nitrogen compounds were assimilated rapidly into the natural food web and there were high rates of sedimentation and re-mobilization of settled nitrogen from the pond bottom. Generally, the modifications to pond management were associated with increased nutrient utilisation efficiencies and resulted in higher net benefits and more stable pond culture conditions. It was shown that plant material from pesticide-treated fields should only be used cautiously as feeds for grass carp because pesticide residues reduce feed intake and adversely affect fish health. Low cost modifications were well accepted by the farmers. Application of supplemental feeds and chemical fertilisers, which required a continual monetary investment, were less well received. The better-educated farmers are more likely to further invest in aquaculture and might act as local adopters. To reduce the costs of feeds for common carp, earthworm has been shown to be suitable as a replacement for fishmeal in feeds. Vermiculture might therefore be a suitable additional farming activity in combination with the implementation of pond management modifications. Formation of fish farmer cooperatives might further increase the acceptability of innovations. The improvements to pond aquaculture that have been developed here may have a beneficial impact on fish production, food security and income of small-scale farmers in the uplands in South-East Asia if the information is suitably transferred through education programmes that train farmers in technologies that have been specially adapted to conditions in the uplands.