Browsing by Subject "Futtermittel"

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    Bestimmung präcecaler Verdaulichkeitskoeffizienten für heimische Energie- und Proteinfuttermittel für die Bio-Hühnermast
    (2016) Ritteser, Carolin; Grashorn, Michael
    To improving the supply of slow growing broiler chicken in organic poultry production with essential amino acids the ileal digestibility (ID) of 15 organically cultivated feedstuffs was determined using a linear regression approach. The ID was determined for three and six week old chickens. The feedstuffs included common cereal species such as wheat, rye, spelt and summer barley, hull-less cereals such as naked barley and naked oats, forgotten cereals or pseudo-cereals such as brown top millet, pearl millet and buckwheat but also corn silage, strip waste of lentils, alfalfa leaves, and clover grass silage (extruded and untreated). The cultivars were added to a basal diet in 3 concentrations in exchange to corn starch. Therefore, the increase for crude protein (CP) and amino acids (AA) resulted from the cultivar only. Titanium dioxide was used as an indigestible marker. Each diet was fed ad libitum between day 15 and 21 d of age to 6 pens of 15 chickens or between day 36 and 42 d of age to 6 pens of 6 chickens, each. On day 21 and/or day 42 birds were killed by carbon dioxide, the chymus was collected and pooled for the 15 or 6 chickens per pen, respectively and analyzed on pen basis. Contents of crude protein, amino acids and titanium dioxide have been determined. The slope of the regression line between the amount of AA intake by feed and the amount of AA digested up to the ileum is considered to be the true ileal digestibility. The crude nutrient contents of the organically grown feedstuffs show different results in comparison to conventionally grown ones. The highest crude protein content was determined for lentils, followed by clover grass silage and dried alfalfa leaves. However, the alfalfa leaves also showed the highest content of crude fiber. Brown top millet, pearl millet, clover grass silage and alfalfa leaves contained the highest amount of methionine. The highest lysine contents were found for lentils, clover grass silage and alfalfa leaves. Values for digestibility of crude protein and amino acids varied strongly among the feedstuffs. Rye, spelt and the clover grass silages were digested only poorly by both, the three and the six week old broilers. This was probably caused by an increased content of antinutritional substances and crude fiber. Extrusion didn´t have any positive effect on the amino acids digestibility of the clover grass silage, it rather impaired digestibility. For buckwheat and clover grass silage the high contents of crude protein and amino acids were compensated by poor digestibility. Brown top millet, pearl millet, strip waste of lentils and especially alfalfa leaves turned out to be appropriate feedstuffs for an adequate protein and amino acids supply in broiler nutrition. Due to the high fiber content alfalfa leaves should be used carefully in the diet. Their high crude fiber content causes an increase in feed volume and this may result in a too low feed intake of broilers to fulfill their nutritional requirements. This again can cause growth disturbances. In general, digestibility values for the organically grown feedstuffs were found to be similar to the values of conventionally grown feedstuffs.
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    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.
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    Studies on the extent of ruminal degradation of phytate from different feedstuffs
    (2017) Haese, Eva; Rodehutscord, Markus
    The predominant storage form of phosphorus (P) in plant seeds and grains is phytate (InsP6). To cleave the phosphate group and, thus, make the bound P available for absorption by the animal, the enzyme phytase is required. Rumen microorganisms show substantial phytase activity, however, recent studies have suggested that the extent of InsP6 hydrolysis in ruminants is variable leading to an incomplete hydrolysis of InsP6 in specific conditions followed by the excretion of P from undegraded InsP6. As P is an essential element for the metabolism in animals it is important to ensure that the animals’ requirements are met. Diets for ruminants are often supplemented with mineral P (Pi). However, the global phosphate resources are finite and the excretion of surplus P contributes to eutrophication of surface water when applied to the farmland with manure in excessive amounts. Thus, dietary P supply is of environmental concern. Better knowledge about ruminal InsP6 hydrolysis could help to optimise the utilisation of InsP6 and, thus, reduce the use of Pi as well as unnecessary excretion of P. Hence, the objectives of the present thesis were to examine the InsP6 hydrolysis from different feedstuffs in ruminants and to identify factors that might affect the extent of InsP6 hydrolysis. In the first study, the total digestive tract disappearance of InsP6 from diets differing in amount and source of P was determined in lactating dairy cows. The results confirmed the high potential of rumen microorganisms to hydrolyse InsP6, but the composition of the diet influenced the extent of hydrolysis in vivo. In the second study, two in vitro experiments were conducted in order to determine the InsP6 hydrolysis from maize grain and RSM. In experiment 1, two diets differing in P- and InsP6-P concentration were fed to the donor animals of rumen fluid. In experiment 2, a diet similar to the high P diet of experiment 1 was fed to the donor animals of rumen fluid and the rumen fluid was mixed with artificial saliva containing Pi (PI: 120 mg Pi/l) or no Pi. Maize and RSM were incubated for 3, 6, 12, and 24 h in both experiments and the InsP6 concentration was analysed in fermenter fluids and bag residues. InsP6 disappearance from maize proceeded faster than from RSM. The disappearance of InsP6 was higher when the diet with high P concentration was fed (experiment 1) and lower when the rumen fluid was mixed with Pi containing buffer (experiment 2). In the third study, the in situ disappearance of InsP6 from five different concentrates was examined. Maize, wheat, RSM, heat treated RSM (hRSM), and soybean meal were incubated in the rumen of fistulated dairy cows fed with three diets differing in P- and InsP6-P concentration. Concentrations of InsP6 and isomers of InsP5, InsP4, and InsP3 were determined in the bag residues after 2, 4, 8, 16, and 24 h of incubation. The disappearance of InsP6 from cereals proceeded faster than from oilseed meals, however, averaged over the diets, after 24 h of incubation 95% had disappeared from all concentrates except for hRSM (57%). Feeding the diet with high InsP6 concentrations increased InsP6 disappearance from oilseed meals but not from cereals, while feeding the high Pi diet did not influence ruminal InsP6 hydrolysis from any concentrate. The results derived from analysis of lower InsPs suggested that intrinsic plant phytase activity plays only a minor role in the rumen and that active phytases in the rumen react differently to changes in the ruminal environment. The results of the present thesis suggest that the composition of the diet fed to ruminants affects the extent of ruminal InsP6 hydrolysis. While high InsP6 concentrations have the potential to increase InsP6 hydrolysis, a decrease of InsP6 hydrolysis can occur after addition of Pi to the diet. Differences in the pace of InsP6 hydrolysis between concentrates occurred which could be of importance at high ruminal passage rates when the time available for ruminal hydrolysis decreases.
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    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.