Browsing by Person "Becker, Klaus"

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A case study: Fish production in the integrated farming system of the Black Thai in Yen Chau district (Son La province) in mountainous North-western Vietnam - current state and potential
(2009) Steinbronn, Silke; Becker, Klaus
Son La province is located in mountainous north-western Vietnam and belongs to the poorest regions of the country. In the valleys of this province, fish farming is one of the major activities among farmers who belong to the ethnic Black Thai minority. Up until now, the aquaculture system practiced here has not been scientifically investigated. There is generally very little data available regarding the aquaculture of resource-poor farmers in Southeast Asia. This lack of information can be partly explained by the difficulty in obtaining this data. However, a solid understanding of current aquaculture systems is necessary for any kind of future involvement. Within the course of a special research program (SFB 564), aquaculture practices in three communes of Yen Chau district (Son La province) were surveyed between 2004 and 2006. The research was conducted in a holistic way in order to obtain a detailed description of the typical local aquaculture system with its potentials and limitations. In addition, measures for improvement were developed, which will be tested during the next phase of the special research program. The data was collected and analyzed on three different levels. On the ?macro level?, general data is presented regarding the land use and irrigation system in the studied area. Data on the ?meso level? concerns the aquaculture and agriculture system and was predominantly collected through interviews with 155 farmers, 22 village headmen and other stakeholders. On the ?micro level?, an in-depth investigation based on measurements and close observation of 6 individually selected case study farms is presented. This data includes the limnological pond conditions, fish growth rates, food conversion and the profitability of the aquaculture system. The data gathered during these investigations compensates for the information that could not be satisfactorily gathered through the interviews alone. Currently, around 63% of the households in the study area produce fish in ponds. The aquaculture production is closely linked with other farming activities and is integrated into the overall irrigation system. Farmers stock different carp and tilapia in polyculture with the main species being grass carp. Fish are mainly fed leaves and by-products of crop production, weeds and manure, e.g. from buffalo. The pond system is feed-based and exhibits a more or less continuous water flow; both of these features are rather atypical for small-scale aquaculture. In the case study farms, the average fish stocking density was 1.0 fish m-2. Calculated based on one hectare, the average daily feed application was 37.1 kg dry matter (DM) and the annual net production of aquatic species 1.5 tons ha-1, of which roughly 2/3 were sold. The average conversion of feed (DM) to aquatic species biomass was 7.7:1, and the conversion of added nitrogen (feed and manure) to produced nitrogen (aquatic species) was 14.7%. The yields in the presented system are relatively low compared to other feed-based aquaculture systems. Nevertheless, it has been shown that aquaculture production contributes significantly to food security, generates income and plays a significant role in farmers? lives. At present, the local market in Yen Chau cannot be completely satisfied by the districts? fish production alone. Recently, a road was upgraded that connects the north-western mountains with the country?s capital Hanoi. As a result, fish from the more intensive aquaculture in the lowlands has started to flood the local markets. This development is expected to proceed, which will leave farmers unable to compete in the market in the future. In order to produce fish in a sustainable way, the current system must be improved so that the local fish production increases. There are various reasons that can explain the relatively low productivity in the ponds. These include an unclassifiable grass carp disease that leads to high mortalities, poor water quality, low fish growth rates caused by low quality of fish seed, low quality of feed and manure applied as well as low natural food availability in the ponds. Furthermore, farmers seem to have limited knowledge regarding basic aquaculture techniques, which may be explained by the lack of training or extension services available in this field. In the present study, a ?basket? of modification measures have been proposed. These measures concern the farms themselves (e.g. improved pond management), the institutional and political framework (e.g. support of the local hatcheries) as well as the research. The focus of the next part of the special research program will be the identification of the causative agent of the grass carp disease and the development of prevention and treatment strategies. Additionally, a modified watering and feeding management system will be tested scientifically. It is expected that this locally adapted, improved pond system will lead to significantly higher fish production.
Comparison of plant cell wall degrading community in the rumen of N’Dama and N’Dama x Jersey crossbred cattle in relation to in vivo and in vitro cell wall degradation
(2004) Nouala-Fonkou, Simplice; Becker, Klaus
This thesis presents a unique combination of an in vivo feeding trial, the analysis of the microbial community structure in the rumen, and in vitro fermentation studies, in order to assess the impact of breeds and diets on animal performance in a West African production setting. Pure N?Dama and N?Dama x Jersey crossbred cattle were fed two basal diets, baby corn and groundnut hay, supplemented with graded levels of either conventional concentrate or moringa leaf meal, to compare animal responses in productivity. In this context, Moringa oleifera leaf meal constitutes a locally available, potential alternative to commercial concentrate for cattle production. The cell wall digesting community of N?Dama and its crosses was analysed using phylogenetically based hybridisation probes to account for the contribution of rumen microbes to differences in fermentation patterns and animal response. In vitro fermentation studies were carried out using the same diets and supplementation levels as fed in vivo, to test the accuracy of the in vitro gas production technique in predicting the optimum level of supplementation. The in vivo feeding experiment focussed on the comparison of breed performance with diets relevant for local production conditions. Six N?Dama and six N?Dama x Jersey (crossbred) animals were used in a cross over design. They were fed consecutively three combinations of roughage and supplement, baby corn stover and concentrate (BCS:Co), groundnut hay and concentrate (GNH:Co) and groundnut hay and moringa meal (GNH:Mo), each at 5 levels of supplementation (0, 10, 20, 30 and 40%). Results from this study showed that there was a clear difference in animal response to different feeding regimes between the two breeds. When averaged over all diets organic matter intake (OMI) was higher in crossbred compared to N?Dama (94 and 87.6 g/kg 0.75 d-1, respectively). When analyzed for the diets and averaged over the breeds OMI was higher when animals were fed the baby corn based diet compared to groundnut based diets (95 against 88 g/kg 0.75 d-1). Only when the diet consisted of BCS:Co, and at low levels of supplementation, N?Dama ingested more than crossbred, but the difference was not significant. With GNH:Co crossbred ingested significantly more at levels of supplementation less or equal to 20%. With GNH:Mo crossbred ingested more, whatever the level of supplementation. The optimum level of supplementation in vivo, estimated with the single slope broken line model, was 10% and 20% for both breeds when they were fed BCS:Co and GNH:Co respectively, but 30% for N?Dama and 10% for the crossbreds when animals were fed GNH:Mo. Organic matter digestibility (OMD) was higher in N?Dama (64.6% against 60.7% in crossbreds) when animals were fed BCS:Co and supplementation had no effect on OMD of BCS:Co whatever the breed. When animals were fed groundnut hay as basal diet, OMD was also significantly higher in N?Dama at low levels of supplementation, but the differences became insignificant beyond 10% and 20% of concentrate or moringa, respectively. With GNH:Co OMD showed a quadratic response (p<0.001) with increasing level of supplementation when it was fed to crossbreds and was not affected when it was fed to N?Dama. Increasing levels of moringa meal supplementation increased OMD in both breeds up to a peak at 20 and 30% for N?Dama and crossbred, respectively. Average daily weight gain (ADG) was not affected by the breed, however it was higher on BCS:Co compared to other diets. On BCS:Co ADG increased with the level of supplementation, reaching a peak at 30%, whereas supplementation had no effect on ADG when animals were fed groundnut hay based diets. As N?Dama could take in and digest more of the low quality BCS:Co diet, they were less efficient in feed conversion under this feeding regime (FCE: 14 vs. 9 for the crossbreds). On GNH based diets, however, N?Dama surpassed the crossbreds in feed conversion efficiency with ratios of 11 vs. 13 for GNH:Co and 9 vs. 27 on GNH:Mo. Rumen microbes play the key role for the digestibility of a given feed and thus also for feed intake and finally animal performance. Obviously, the community composition and activity is highly dependent on the diet. With the present set-up, however, with identical external conditions and three different, well defined diets fed to both, N?Dama and crossbred cattle, a comparison of the microbial community structure between breeds could be attempted. The in vivo and in vitro data taken in the other parts of the study allow a sensible interpretation of potential changes in microbial composition. Rumen fluid was collected from three fistulated N?Dama and three crossbred animals adapted to the experimental diets at medium supplementation level. The cell wall degrading community was analyzed using the phylogenetically based 16S rRNA hybridisation probes. The results showed that on BCS:Co diet the Fibrobacter and R. flavefaciens RNA concentrations were higher in rumen fluid of N?Dama compared to crossbred. These concentrations were also significantly affected by the diet, such that they were higher on baby corn stover compared to groundnut hay based diets. The results of the microbial community analysis suggested that the differences between breeds observed in digestibility could be partially explained by the composition of the cell wall degrading community. Parallel to the in vivo experiment, in vitro fermentation studies were undertaken to evaluate the predictability of the in vivo response to supplementation by the in vitro data. Rumen fluid from 3 N?Dama and 3 crossbred donor animals was used for 24 hour in vitro fermentations. The donor animals were fed consecutively the same three diets used in vivo (BCS:Co, GNH:Co and GNH:Mo) at 20% level of supplementation. Each of these inocula was incubated with in vitro substrates consisting of all the combinations tested in vivo (i.e. 3 diets, 5 levels of supplementation) plus supplement alone. This design should allow to analyze for both, the impact of donor breed as well as that of the donor diet and to conclude which factors may be varied while maintaining predictability. The breed of the donor animals did not significantly affect 24 hour gas production, but short chain fatty acid concentration was higher with rumen fluid from crossbreds when donors were fed BCS:Co and GNH:Mo. Moringa meal as supplement to donor animals changed the fermentation pattern of all the substrates, such that gas production and SCFA increased substantially in groundnut hay based substrates, whereas gas production of BCS:Co substrates decreased and SCFA did not substantially change. In vitro digestibility was higher with rumen fluid from N?Dama whatever the diet of donor animals and the substrate incubated. GNH:Mo as donor diet also increased IVTD of all the substrates. Even though there was no clear response in vivo, this indicates a general stimulation of microbial activity in the rumen and renders moringa leaf meal a promising supplement. Averaged over all data there was a positive correlation (r2=0.53 p<0.001) between IVTD and in vivo OMD. This correlation was much stronger when calculated for a specific diet (e.g. r2=0.90 p<0.001 for BCS:Co, averaged over the breeds). Analyzing the data for the individual breeds affected correlations only to a minor degree. Thus, when testing a supplementation strategy in vitro, it should be important that donor animals are fed the same components (roughage and supplement) that will be combined at different levels in vitro, whilst the breed of donor animals may be of second importance. This work provides conclusive evidence that in vitro incubations may be used to design supplementation strategies, thus reducing the need for in vivo experiments. Moringa leaf meal is a promising local resource to substitute for conventional concentrate. Differences in productivity between breeds could be correlated to (and may be partially manifested through) a divergent community structure of rumen microbes. That, in turn, indicates that animals of different breeds might have a ?genetic background? that favours the establishment of a certain community, even if the animals are kept under identical conditions. This relationship should be investigated by more advanced molecular techniques.
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.
Influence of tropical supplemental feeds on the composition and activity of rumen microorganisms, quantified by oligonucleotide probes
(2001) Muetzel, Stefan; Becker, Klaus
This study was undertaken to evaluate the applicability of oligonucleotide probes to unravel the population structure of the rumen flora in vitro. At first a RNA extraction and cell lysis method for rumen fluid samples was optimised. However when tannin containing plants were present in the samples the method failed to recover microbial RNA. The comparison of two rumen fluid sampling sites for inoculation revealed a higher in vitro gas production from samples inoculated with rumen fluid from the feed mat compared to the liquid phase. The higher gas production was not explained by a higher digestibility of the substrates. Changes in the population structure, population density and the kinetic of the fermentation might be responsible for the observed differences. This experiment showed that for interpretation of the results, population structure data have to complemented with metabolic parameters. In a supplementation experiment it was demonstrated that amount, but also the efficiency of the microbial biomass production was positively affected. Comparison of the population structure of the cell wall degrading consortium and cellulase activity revealed that Fibrobacter was mainly responsible for the expression of this enzymatic activity. Such a comparison is a new strategy which will lead to a better understanding of the complex fermentation processes in the rumen. The analysis of the population structure of the cell wall degrading organisms showed a competition for substrate or attachment sites between Fibrobacter and Ruminococcus albus which was independent of the substrate incubated, the time of sampling and the origin of the inoculum.
Isolation, characterization and potential agro-pharmaceutical applications of phorbol esters from Jatropha curcas oil
(2012) Devappa, Rakshit K.; Becker, Klaus
Biodiesel is generally prepared from renewable biological sources such as vegetable oils by transesterification. Jatropha curcas seed oil is a promising feedstock for biodiesel production. During biodiesel production from Jatropha oil, many co-products such as glycerol, fatty acid dis-tillate and seed cake, among others, are obtained. The efficient use of these co-products would enhance the economic viability of the Jatropha based biofuel industry. However, the possible presence of phorbol esters (PEs) in these co-products restricts their efficient utilization. During biodiesel production, Jatropha oil is subjected to many treatments (stripping, degumming and esterification) wherein PEs present in the oil undergo partial or complete destruction depending on the treatment conditions. One of aims of this study was to develop and integrate methodolo-gies for using the PEs as a value added product instead of simply allowing them to be destroyed during biodiesel production. Potential uses of the phorbol ester enriched fraction (PEEF), ob-tained from Jatropha oil in agro-pharmaceutical applications were also investigated. The reason for choosing this group of compounds (PEs) was that they are highly bioactive both in vitro and in vivo, but they are currently considered to be merely toxic, unwanted biomaterial in the Jatro-pha biodiesel production chain. The recent increase in the cultivation of Jatropha cultivation means that there are potentially huge quantities of PEs that could be used for many purposes. This study revealed that a large proportion (85.7%) of PEs was localized in the endosperm portion of the Jatropha seed. Interestingly, the kernel coat contained PEs in high concentration. The endosperm portion of the kernel also contained antinutritional factors such as phytate (96.5%) and trypsin inhibitor (95.3%). The presence of high levels of antinutritional/toxic com-ponents in the kernel was presumed to be one of the factors that protect Jatropha seeds against predatory organisms during post harvest storage. Based on the presence or absence of PEs, a qualitative method was developed to differentiate between toxic/nontoxic Jatropha genotypes. In this method the methanol extract of seeds is passed through a solid phase extraction (SPE) column and the absorption (280 nm) of the result-ing eluate is measured. After screening Jatropha seeds collected from different parts of the world for toxic and non-toxic genotypes using the pre-established HPLC method for PEs, a cut off value of the absorbance was set up to differentiate toxic and nontoxic genotypes. Raw kernels whose SPE eluates had an absorbance ≥0.056 were considered as toxic and ≤0.032 as nontoxic. Corresponding absorbances for the SPE eluates of defatted kernel meal were ≥0.059 (toxic) and ≤0.043 (nontoxic). However, confirmation of the presence of PEs especially in Jatropha products for food applications should be carried out using the pre-established and validated HPLC method. The developed qualitative method could find its applications for screening the toxicity of products and co-products obtained from the Jatropha biodiesel industry. Conditions were optimized for the extraction of PEs as a phorbol ester enriched fraction (PEEF) from Jatropha oil using methanol as a solvent and a magnetic stirrer/Ultra-turrax as ex-traction tools. The extent of PE reduction in Jatropha oil was >99.4% using methanol as the sol-vent. The PEEF obtained (48.4 mg PEs/g) was 14 fold higher in PEs than in the original oil and this fraction was highly bioactive as determined by the most sensitive snail bioassay (LC100, 1 ppm) (see below). As the removal of PEs from oil took 60 min, which might be considered a long time in an industrial process, further conditions were optimized to extract maximum PEs in the shortest possible time with minimum solvent. The tools used for PE extraction (Ultra-turrax and magnetic stirrer) were effective with a treatment time of 2 and 5 min, resulting in 80 and 78% extraction of PEs, respectively. The biodiesel prepared from both the residual oils met European (EN 14214:2008) and American biodiesel standard (ASTM D6751-09) specifications. It was evident from the study that PEs could be easily extracted by either of the two methods with a high yield and the residual oil could be processed to produce high quality biodiesel. Also the residual oil with a lower PE content is expected neither to harm the environment nor the workers who had to handle it. The extracted PEEF was evaluated for its agricultural potential as a bio control agent. The PEEF had a high biological activity in aquatic bioassays using snails (Physa fontinalis), brine shrimp (Artemeia salina) and daphnia (Daphnia magna), when compared with microorganisms. The EC50 (48 h) of the PEEF was 0.33, 26.48 and 0.95 ppm PEs for snail, brine shrimp and daphnia respectively. High MIC (minimum inhibitory concentration) values (≥215 ppm) and EC50 values (≥58 ppm) were obtained for both the bacterial and fungal species. Among the bio-assays tested, the snail bioassay was the most sensitive, producing LC100 at 1 μg of PEs/ml. The snail bioassay could be used to monitor the presence of PEs in various Jatropha derived products, contaminated soil and other matrices in the ecosystem that might be involved in the production or use of Jatropha and its products. The study also demonstrated that the PEs exhibit molus-cicidal, antifungal and antibacterial activities. The shelf life of the PEEF was investigated. The PEEF was more susceptible to degradation when stored at room temperature (50% degradation after 132 days) than when stored at 4 °C or -80 °C (8% and 4% degradation respectively). Similarly, the PEEF lost biological activity (the snail bioassay) more rapidly at room temperature becoming ineffective after 260 days; while at 4 °C and -80 °C, only 27.5% and 32.5% activity was lost after 870 days. The degradation of PEs was due to auto-oxidation. Changes in fatty acid composition, increase in peroxide value and decrease in free radical scavenging activity of the PEEF reflected the auto-oxidation. Inclusion of antioxidants as additives (butylated hydroxyanisole (BHA), Baynox and α-tocopherol) pro-tected the PEs against degradation. The study demonstrated that the PEEF was susceptible to oxidation and addition of antioxidant stabilised the PEs during storage. In soil, PEs present in both the PEEF (2.6 mg/g soil mixture) (silica was used to adsorb PEs) and Jatropha seed cake (0.37 mg/g soil mixture) were completely degraded as the temperature and moisture content of the soil increased. PEs from silica-bound PEEF were completely de-graded after 19, 12, 12 days (at 13% moisture) and after 17, 9, 9 days (at 23% moisture) at room temperature (22 −23°C), 32 °C and 42 °C respectively. Similarly, at these temperatures, PEs from seed cake were degraded after 21, 17 and 17 days (at 13% moisture) and after 23, 17, and 15 days (at 23% moisture). The toxicity of PE-amended soil extracts when tested using the snail bioassay decreased with the decrease in PE concentration. The study demonstrated that PEs pre-sent in the PEEF or Jatropha seed cake are completely biodegradable in soil and the degraded products are innocuous. In preliminary studies, the PEEF exhibited potent insecticidal activity against Spodoptera frugiperda, which is a common pest in corn fields damaging maize crop across the tropi-cal/subtropical countries such as Mexico and Brazil. The PEEF produced contact toxicity with an LC50 of 0.83 mg/ml (w/v). The PEEF at higher concentration (0.25 mg/ml, w/v) also reduced food consumption, relative growth rate and food conversion efficiency (FCE) by 33%, 42% and 38% respectively. The study demonstrated that the PEEF has a potential to be used as a bio-control agent. Further in-depth field experiments on the effects of the PEEF on S. frugiperda will pave the way for its use under field conditions. The pharmaceutical potential of Jatropha PEs was also investigated. The PEs from Jatropha oil were purified. At least six purified PEs (designated as factors C1 to C6) were present in Jatropha oil. The identities of the purified PEs (factors C1 and C2) were confirmed by NMR. Whereas, factor C3 and factors (C4 + C5) were both obtained as mixtures. However, comparison of peak areas for phorbol 12-myristate 13-acetate (PMA) and Jatropha factor C1 in the HPLC method showed a difference in sensitivity of absorption at 280 nm of 41.3 fold. All the individual purified Jatropha PEs (factors C1, C2, C3mixture and (C4+C5)) and PEs-rich extract (factors C1 to (C4 + C5)) were biologically active when tested in the snail and brine shrimp bioassays. In ad-dition, all the Jatropha PEs produced platelet aggregation in vitro with an effective order of (based on ED50 (μM)): Jatropha factor C2 < factor C3mixture < factor C1 < factor (C4+C5). The PEs-rich extract (contains factor C1 to C6) was toxic to mice upon intra gastric administration, with an LD50 of 27.34 mg/kg body mass as PMA equivalent or 0.66 mg/kg body mass as factor C1 equivalent. The prominent histopathological symptoms were observed in lung and kidney. The Jatropha purified PEs-rich extract, purified PEs (factor C1, factor C2, factor C3mixture and factors (C4+C5)) and toxic Jatropha oil produced severe cellular alterations/disintegration of the epithelium and also increased the inflammatory response (interleukin-1α and prostaglandin E2 release) when applied topically to reconstituted human epithelium (RHE) and human corneal epithelium (HCE). In RHE, the nontoxic oil (equivalent to the volume used for toxic oil) pro-duced a lower cellular and inflammatory response than the toxic oil and the response increased with an increase in concentration of the PEs. In HCE, nontoxic oil (equivalent to the volume used for toxic oil) produced marked cellular alterations. The study demonstrated that the pres-ence of PEs in Jatropha oil increased the toxicity, both towards RHE and HCE. In addition, all the purified Jatropha PEs gave positive responses in the tumour promotion assay and negative responses in the tumour initiation assay in vitro (the assay was based on foci formation in Bhas 42 cells). In the tumour promotion assay, the order of transformed foci/well formation was: PEs-rich extract > factor (C4+C5) > factor C3mixture > factor C1 > factor C2. The tumour promotion ac-tivity was mediated by the hyper activation of protein kinase C (PKC). The aforementioned studies demonstrated that Jatropha PEs are toxic when administered orally or when applied topically to the skin or eye tissues. The data obtained should help in establishing safety measures for people working with Jatropha PEs. The potential of Jatropha PEs as a feedstock intermediate for the synthesis of Prostratin, a promising adjuvant in anti HIV therapy, was evaluated. The studies demonstrated that the Jatro-pha PEs could be synthesized sequentially by converting them first to crotophorbolone and then to prostratin. As analyzed by Nano-LC-ESI-MS/MSR, the prostratin synthesized from Jatropha PEs had similar mass and peak retention time to the reference prostratin (Sigma, St. Louis), The study showed that prostratin could be synthesized from Jatropha PEs. However, further optimi-zation studies are required to ascertain the synthesis reactions and yield of prostratin synthesized from Jatropha PEs. Some of the preliminary requirements for any successful bio-control agent are that it should have a high bioactivity on the target organism, a long shelf-life and a high biodegradability in soil. In addition, the bioactive phytochemical should be available in large quantities, it should be easily extractable and continuously available. The PEEF potentially satisfies these aforesaid re-quirements. The abundance and novelty of PEs present in Jatropha species could form a new ?stock? for the agro-pharmaceutical industries. Considering the projected oil yield of 26 million tons/annum by 2015 (GEXSI, 2008), huge amount of raw materials will be available for both biodiesel and pharmaceutical industries. PEs in the form of the PEEF could be used either as in-sect controlling agents in agricultural applications or as a ?stock? biomaterial for synthesizing prostratin in pharmaceutical applications.
Jatropha meal and protein isolate as a protein source in aquafeed
(2011) Kumar, Vikas; Becker, Klaus
As aquaculture continues to develop, there will be an increasing need to use alternative plant proteins in aquaculture diets so that aqua eco-systems will be sustainable. Jatropha (DJKM, H-JPKM and DJPI) can be used as protein rich sources in the diets of fish and shrimp. There is a high potential for the safe use of DJKM, H-JPKM and DJPI in diets for fish and shrimp without compromising performance, provided that these ingredients are free of toxic factors. The detoxification process developed in Hohenheim is simple and robust and produces products that are safe and of good quality. Their addition to fish and shrimp diets gave excellent performance responses without any ill effects on animal health or safety. Effects on growth and nutrient utilization: ? Detoxified Jatropha kernel meal, H-JPKM and DJPI could replace 50%, 62.5% and 75% fish meal protein respectively without compromising growth performance and nutrient utilization in fish. In addition, DJKM could also replace 50% fish meal protein with no adverse effects on growth and nutrient utilization in shrimp. If the replacement levels are exceeded, the producer must examine the nutrient profile of the feeds carefully to ensure that desired production levels can be achieved and fish and shrimp health maintained. ? High inclusion (>50% fish meal protein replacement) of DJKM decreased the efficiency of conversion of feed to body mass. This could be explained partly by the increased mean feed intake which was possibly a reaction to the reduced protein retention, measured as protein efficiency ratio and protein productive value. No such effects were seen with the use of DJPI in common carp diets. ? Increased DJKM inclusion in diets caused a significant lowering of protein, lipid and energy digestibilities. No such effects were seen when DJPI was used in common carp diets. Effects on energy budget: ? Feeding DJKM and H-JPKM to common carp and Nile tilapia respectively did not change the major components of the energy budget (routine metabolic rate, heat released and metabolisable energy) compared to fish meal and soybean meal fed groups. These results revealed that dietary protein sources DJKM and H-JPKM can be efficiently utilized for growth by common carp and Nile tilapia respectively, as well as soybean meal and fish meal. Effects on expression of growth hormone and insulin-like growth factor-1 encoding genes ? As the level of DJKM inclusion increased in the common carp diet, growth rate decreased. The expression of Insulin-like growth factor-1 (IGF-1) in liver also decreased with increase of DJKM in the diet and that of the growth hormone in liver decreased. Effects on clinical health parameters and gut health: ? No mortality and unaffected haematological values suggested the fish were all in normal health. Alkaline phosphatase and ALT activities; urea nitrogen, bilirubin and creatinine concentration in blood were in the normal ranges which showed that there was no liver or kidney dysfunction. ? The measured plasma nutrient levels gave no indications of stress, but increasing the level of plant protein in the diet decreased plasma cholesterol. This may be related to high NSP content or reduced dietary intake of cholesterol. Decrease in muscle cholesterol level is also expected which could be considered good for human health. ? Histopathological evaluation of organs showed no damage to the stomach, intestine or liver of common carp or rainbow trout. Effects of Jatropha-phytate in Nile tilapia The defatted Jatropha kernel meal obtained after oil extraction is rich in protein (58−66%) and phytate (9 −11%). The phytate rich fraction was isolated from defatted kernel meal using organic solvents (acetone and carbon tetrachloride). It had 66% phytate and 22% crude protein and its inclusion in fish diets showed the following: ? Negative effects on growth performance, nutrient utilization and digestive physiology (nutrient digestibility and digestive enzymes). ? Adverse influences on biochemical entities such as metabolic enzymes (alkaline phosphatase and alanine transaminase) and electrolytes/metabolites. Salient changes include decreased red blood cell count and hematocrit content, decreased cholesterol and triglyceride concentrations in plasma and decreased blood glucose levels. The adverse effects observed may be due to the interaction of phytate with minerals and enzymes in the gastro intestinal tract, resulting in poor bioavailability of minerals and lower nutrient digestibility. The level of phytate used in the present study (1.5 and 3.0%) corresponds to 16.5% and 33.0% of DJKM in the fish diet. The DJKM at levels > 16.5% in the diet would exhibit adverse effects in Nile tilapia. Addition of phytase to the phytate containing diets would mitigate the adverse effects of at least up to 3% Jatropha phytate (or 33% DJKM) in the diet. Addition of phytase (1500 FTU/kg) in diets containing DJKM is recommended to maximize their utilization by Nile tilapia.
Seasonal variation in growth, quantitative and qualitative food consumption of milkfish, Chanos chanos (Forsskål 1775), and Nile tilapia, Oreochromis niloticus (L. 1758), in Laguna de Bay, Philippines
(2002) Richter, Hartmut; Becker, Klaus
Laguna de Bay, the largest lake in the Philippines, lies directly southeast of the capital Manila. The lake has a mean depth of only 2.8m and a muddy bottom which is stirred during windy weather, causing turbid conditions (Secchi depth <30cm). In the dry season, the water level drops below that of the nearby sea, leading to a backflow of saline water which clears the water until the return of the monsoon winds (Secchi depth >100cm) and leads to algal blooms. Since the beginning of the 1970s, the lake has been used for culturing milkfish, Chanos chanos (Forsskål), in large netpens (max. 2000ha) and Nile tilapia, Oreochromis niloticus (L.), in smaller cages (max. 200m2). Initially, it was possible during the algal blooms to grow fish from fingerling (ca. 10g) to marketable size (ca. 200g) in three months, making two harvests a year possible. Aquaculture quickly spread until in the middle of the eighties, over a third of the lake was covered with cages. At the same time the growth of the fish declined, which was attributed to the excessive use of primary production. Since then, despite a reduction in aquaculture coverage to the generally recommended level of 10% of the lake, fish growth has never reached the levels of the early days of culture. In the present work, seasonal variation in growth, feeding spectrum and daily ration of these two species was to be investigated in relation to water quality in order to find out more about the interaction between aquaculture and the lake. Between May 1995 and August 1997, milkfish and tilapia were sampled on several occasions at commercial operations over the 24-hour cycle. Since milkfish, unlike tilapia, do not receive supplemental feed, the proportion of their growth derived only from natural food could be determined from the cultured fish. Tilapia were kept in cages without feed specially for this purpose and measured and weighed twice a month between March and November 1997. At the same time, selective water quality parameters (particulate organic and inorganic matter, Chlorophyll-a, zooplankton) were analysed weekly. The growth of unfed fish was significantly faster between saltwater intrusion (mid-May) and the return of the monsoons (late July) than at other times of the year. On the other hand, food consumption was only slightly higher in tilapia when the water was clear than at other times and in milkfish hardly differed over the year. Both species mainly fed on amorphous organic detritus; significant levels of phytoplankton were only found in the stomachs at times of algal bloom. In supplemented tilapia, the daily ration still consisted of 35-75% natural food, suggesting that pelleted feed was used inefficiently. The main factor limiting fish growth therefore seemed to be food quality since detritus has often been shown to be poor quality food. The weekly water samples collected in 1997 demonstrated that the total level of phytoplankton was not necessarily higher at times of rapid fish growth. The main difference was related to algal size, since at times of turbid water, small diatoms dominated but these were replaced by larger blue-green algae after saltwater intrusion. In conjunction with the feeding method of these fish, the strongly seasonal growth of the fish could now be explained. Phytoplanktivorous fish such as milkfish and tilapia can only select their food on the basis of size. Since the organic detritus in the lake consisted of particles smaller than 15µm, it was possible for the fish to selectively filter larger blue-green algae but not smaller diatoms. This could also explain why fish growth rates did not recover after a reduction in aquaculture in the mid-eighties, since the relationship between the level of algae and that of detritus seems to be more important than total algal biomass. In order to increase production to those levels found in the early seventies, the level of detritus in the lake would have to be reduced, for which its origin would have to be investigated first.
Studies on the nutritional quality of plant materials used as fish feed in Northern Vietnam
(2009) Dongmeza, Euloge Brice; Becker, Klaus
Fish demand has risen worldwide as populations have grown and incomes have increased; thus, fish are highly likely to continue becoming more expensive over the next two decades. This situation could endanger the availability of fish to the lower income groups and poor people in developing countries. Fisheries and aquatic products are an important source of protein in Vietnamese diets. However, in the upland areas, fish is scarce and expensive, and signs of protein malnutrition such as discoloration of hair and skin could be frequently observed among the poor inhabitants of Son La province, Northern Vietnam where the average price for fish on the local market was approximately 1.4 US$ kg-1 in 2005 which can be considered high, particularly when compared to the monthly per capita income in Son La of approximately 13.4 US$. Nevertheless, in the villages of that region nearly all households have at least one pond. The major inputs to the ponds system are crop leaves and residues and occasionally grasses and weeds. The annual fish production is low in the region. The aquaculture system in this region is lacking in adequate feed and feeding concept for the different fish species kept here. Fish are cultured in tilapia and cyprinid-based polyculture, the main species being grass carp which is the only species capable of efficiently ingesting and digesting the soluble cell contents of the leaf material used as input to the pond system. Despite these constraints, fish farming contributes enormously to food security in the region and generates incomes. Up to now, none of the feeds currently used in Son La Province have been analysed or tested. Therefore in the first part of this study presents a quantitative evaluation of the gross chemical composition, energy and antinutrient content of the plant residues used as fish feed in the course of the year in Son La Province, Northern Vietnam. The potential of some of these plant materials (such as Banana, cassava and bamboo leaves) to be used all over the year as fish feed depending on the seasonal variation of their nutrient, energy and antinutrient compositions has been presented. In this study, the analysis of the different feedstuffs fed to fish in northern Vietnam showed that some of them had relatively high protein and low fibre content. However, for some of the feedstuffs the antinutrient content was high. During the second part of this work, feeding experiments were conducted simultaneously in a computer controlled respirometer system, which allowed feeding and continuous measurement of oxygen consumption and in a water recirculation aquaria system where the faeces collection was more viable and the apparent digestibility and metabolisibility of the nutrients and energy of six of these plant residues in grass carp have been determined. The simultaneous measurement of the oxygen consumption of the fish fed the diets containing the different plant leaf materials gave accurate informations on the metabolic cost (amount of O2 consumed per unit of body mass gain) of the utilization of the diets containing these plant leaves. The results of the present study indicate that the protein and other nutrients of banana and fresh maize leaves are valuable supplements in fishmeal-based diets for grass carp as they meet the nutritional demands and excel a fast growth of these fish. The findings clearly show that fresh and dry leaf material can be differently digested by grass carp; moreover the study clearly shows the role of dietary plant fibres and some antinutrients on nutrient assimilation in grass carp. The information provided in this study is a good base for scientists and extension workers for the development of improved feeding strategies in many tropical poor countries in the world based on plant materials available locally for herbivorous fish like grass carp. These findings should be further tested under pond conditions as they could lead to an increase of fish productivity with plant based feeds and enhance the livelihood of the small-scale farmers in the rural areas.