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The possibility of increasing at the conjugated linoleic acid content in pork
27-32Views:173The composition of fatty acids in food products is a significant factor in human health. Feeding can significantly influence the composition of fatty acids in the animal fat. We analysed the effect of feeding high CLA-content (conjugated linoleic acid) feed on the composition of fatty acids in pork. The animals were grouped according to the following: Group 1) feeding experimental, ghee-mixed feed for 76 days, Group 2) feeding the same feed, but only for 33 days, Group 3) feeding sunflower-oil-mixed feed for 76 days. Ghee contains CLA in high amount. The aim of our experiment is to analyse how the high CLA content influences the fatty acid content of pork. In the end of the fattening experiment the animals were slaughtered, then samples were taken from the loin, ham, abdomen and backfat from 10 animals from each group and analysed the fatty acid content. We found significant differences between the average fatty acid content of the samples. As an effect of feeding ghee-enriched feed, the CLA content significantly increased, compared to the control group. However, the linoleic acid and the arachidonic acid content were lower, and the proportion of fatty acids was also lower when feeding control feed.
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Does the feeding frequency influence the growth performance of European perch juveniles (Perca fluviatilis) during intensive rearing?
123-128Views:149The European perch (Perca fluviatilis) is a predatory fish species. Its aquaculture production is increasing worldwide. Feeding and the frequency of feeding are important elements of intensive fish rearing. The aim of our experiment was to examine the optimal distribution of the amount of feed, at the same feed rations. The experiment lasted 42 days. Three treatments were applied in 4–4 replications. The first treatment was feeding twice per day (T2), the second treatment was feeding three times a day (T3), and the third group was fed four times a day (T4). 10 European perch juveniles were stocked per tank, with an individual mean body weight of 3.93 ± 0.06 g at the start of the experiment. The survival rate (S%) was above 90% for all treatments. The T2 treatments produced the most favourable harvest weight (13.96 ± 0.14 g) and specific growth rate (SGR = 3.08 ± 0.01% day-1), but no significant differences were observed between groups. In terms of feed conversion ratio, the best result was obtained by (T3) (FCR =1.06 ± 0.18 g g-1), but no significant difference was found for this indicator neither. The results of the trial indicate that the feeding frequency does not influence the production parameters.
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Preliminary results on Siberian sterlet (Acipenser ruthenus marsiglii) fries rearing under intensive conditions
27-31Views:135In our experiments production performances of Siberian sterlet were tested under intensive tank conditions. During the 25 days long experiment effectiveness of weaning to artificial diet of the fish was investigated. Production performances of fish fed on exclusively dry diet from the beginnings were lower than the other two groups. Between the values of sterlets fed on live food also then suddenly vs. continuously were weaned to dry diet there were no significant differences. Based on our results live food feeding could be suggested for the Siberian sterlet larvae for some days but the method of the weaning to dry diet has no significant influence to the production performances.
In 21 days long experiment four different feeding frequencies were tested in Siberian sterlet (~13 g) fingerlings. Dry feed was offered for the fish continuously, 2, 3 and 4 times per day. There were no significant differences between the values of the four treatments. Based on our results there is no high influence of feeding frequency in case of this size group of Siberian sterlet.
During the nursing in two different size groups of Siberian sterlet the optimal daily amounts of feed were aimed to determine. In case of growth values of the group fed at 7% of the total biomass were higher than the other two groups (3 and 5%). Feeding performances of fish fed at 5% were significantly better than fish fed at 7%. Based on our results for ~20 g size of the subspecies at least 5% of total body weight could be suggested.
In case of ~150 g size of the fish the production performances of fish fed at 1% were lower than the other two groups (2 and 3%). Between the values of stocks fed at 2 and 3% there were no significant differences. Based on these results 2% of total body weight of dry feed could be suggested for the Siberian sterlet with ~150 g body weight.
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Possibility of oil seeds in feeding dairy cows
67-73Views:210The efforts to modify the fatty acid composition of milk have intensified with health conscious nutrition coming to the forefront.This experiment of ours was designed to investigate to what extent the natural-based feed additives, such as oilseeds, can influence the fatty acid composition of cow’s milk.Further information was gained about feeding of oilseeds in specific amounts to be fitted into the technology of a large-scale dairy farm in practice. The feed supplements were whole, untreated rapeseed and whole, untreated linseed, as part of a total mixed ration. In case of saturated fatty acids when supplementing with whole rapeseed the most significant change was observable in the concentration of the caprylic acid, capric acid, undecylic acid, lauric acid, myristic acid, stearic acid. In case of unsaturated fatty acids the quantity of oleic acid enhanced considerably. When observating the feeding with whole linseed the concentration of many saturated fatty acids lowered (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid). The quantity of some unsaturated fatty acids was showing a distinct rise after feeding with linseed, this way the oleic acid, α-linolenic acid, conjugated linoleic acid, eicosadienoic acid. The aim of the study was to produce food which meets the changed demands of customers, as well.
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Heat treated feeds in turkey feeding
19-22Views:144The main aim of our study was to determine the effect of expanded and pelleted feeds, as well as the only pelleted feed based on wheat and corn, on the production of turkeys. In May 2006,, a fattening experiment on turkeys was started on the starter farm of Habar Ltd in Szarvas, owned by the Gallicoop Corporation. 17 day old male turkeys were involved in the fattening experiment. The experiment lasted 117 days. At that time, theanimals were 134 days old. After the experiment was completed, they were slaughtered. The following parameters were examined: growth, feed conversion ratio, carcass traits. Turkey feed were produced separately at different times. Similarly to the standard method of turkey fattening, 8 phases feeding was carried out. The fattening experiment was adjusted on male turkeys in 4×12×6 grouping (4 treatments: expanded and pelleted, and only pelleted corn and wheat feed; 12 repeats: number of pens/treatments; 6 birds/pen) 6-6 turkeys from 12 pens per each treatments were measured individually from the 17th day (starter) and at the time of each following feeding changes and mortality. The average of the group was calculated. The average daily weight gain, proportion of the given feed per pen, feeding changes and mortality were determined. The average daily feed intake and the feed conversion ratio were calculated.
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Presence, feeding and health status of collared doves (Streptopelia decaocto Friv. 1838) on animal breeding farms
49-54Views:139In the course of our examinations we were determining the gender of collared doves (Streptopelia decaocto) feeding at animal breeding farms by biometric data. We were estimated their nourishment and necropsies were carried out.
We compared the results of the nutrition analysis with similar data of collard doves feeding at agricultural areas.
We analyzed the crop and gizzard content and recorded the body proportions of collard doves that were captured between December of 2004 and August 2005. In the course of the necropsy examinations we did parasitological, bacteriological examinations as well as examinations for the detection of Newcastle disease. In the course of the gender analysis of the collard doves that were collected at animal breeding farms, both the wing length and the length of the third quill-feather has shown a significantly greater value in the case of males (p>0.05).
From the orts found in the crop and gizzard it has been stated that the feed consumed the most was corn (80.77% m%). The collared doves consumed much less other cereal seeds (wheat 0.82%, barley 1.26%).
In the course of the necropsy examinations done in the Veterinary Institute of Debrecen, the birds proved to be free of parasites, and the results of the Salmonella and Newcastle disease analysis were negative as well. E. coli bacteria had been detected in the liver of not more than three birds. -
Strategic Steps in the Sheep and Goat Branches
61-68Views:146The balance of the sheep and goat branches can be summarised as follows:
If the increase in stock size, specific yields, genetic improvement and modernisation are not realised, several thousand shepherds will lose their jobs and possibilities to work, and their families will lose their only source of livelihood.
Several hundred hectares of grassland will become weedy and the costs of crop protection will increase in these regions. Pollen pollution, the number of allergic ailments and medical costs will increase, mentioning only the main disadvantages. Its financial requirement is nearly equal to the one required for development without any essential compensation or production.
In order to develop a competitive branch, a subsidisation of 10-20 billion HUF is needed until the accession of Hungary to the EU, depending on the scale and progressivity of development. The subsidisation and realisation of the strategic steps would result in:
– the establishment of a registered livestock with 1.5 million ewes, which would ensure better market position for the branch in the EU (5%),
– the establishment of a competitive and marketable branch with a production value of 15-25 billion HUF, calculated using the present price level (after accession, the branch would be self-operating and profitable, with the 6-8 billion HUF/year normative subsidisation by the EU),
– the establishment of a genetic potential which would ensure our participation in profitable international breeding animal market, which provides extra profit,
– the establishment of a sheep husbandry with better genetic potential and phenotypic performance, producing a quality of international level,
– the maintenance of the workplace of more than 10.000 people (saving 3-5 billion HUF/year of the budget),
– the maintenance of the condition of growing areas of grasslands with their advantages (crop protection and public health) whose financial effect is considerable. -
Effect of sex on some composition traits of wild boar (wild pig) meat
25-29Views:274The authors examined the nutrition value of the meat of shot wild boars (wild pigs) (n=66) from three wild boar enclosures with different feeding intensity and also the technological properties of the meat. Samples were taken immediately after the evisceration. Considering the storing and processing properties of game meat the samples were taken from m. serratus anterior. As for dry matter examination results, the highest values were measured in case of semi-intensively fed wild boars, then followed the data from the samples of intensively and extensively fed wild boars. The fat content from the meat samples of intensively and extensively fed wild boars proved to be lower while in case of the semi-ntensively fed wild boars it was higher. In females the dry matter content, while in males the fat content was higher. As for the protein content there were no differences in either the feeding groups or in the genders. It was only the water holding capacity of the samples from the meat of the females from semi-intensive feeding intensity wild boar enclosure that fell in between normal values.
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Effect of feeding linseed on the fatty acid composition of milk
45-50Views:281In the last decades many researches were made to change the animal product food’s composition. The production of better fat-compound milk and dairy products became a goal in the name of health conscious nutrition. These researches were motivated by the non adequate milk fat’s fatty acid composition. There have been made researches in order to modify the milk’s fatty acids’ composition to reach the expectations of functional foods. With the optimal supplement of the feed can be increased the proportion of the polyunsaturated fatty acids and can decreased the saturated fatty acids. Row fat content of milk was not decreasing in the course of examination neither of the cold extruded linseed nor the whole linseed supplement as opposed to observations experienced by other authors. In case of monounsaturated and polyunsaturated fatty acids when supplementing with cold extruded linseed the most significant change was observable in the concentration of the elaidic acid, oleic acid, linoleic acid, alfa-linolenic acid, conjugated linoleic acid. In case of saturated fatty acids the quantity of palmitic acid and myristic acid lowered considerably. When observating the feeding with whole linseed the concentration of many fatty acids from the milkfat of saturated fatty acids lowered (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid). The quantity of some unsaturated fatty acids was showing a distinct rise after feeding with linseed, this way the oleic acid, alfa-linolenic acid, conjugated linoleic acid, eicosadienoic acid. The aim of the study was to produce food which meets the changed demands of customers as well. The producing of milk with favourable fatty acid content from human health point of view can give scope propagate the products of animal origin. -
Feeding questions of organic lamb fattening
155-160Views:104Organic farming has done in line with conventional farming in the Karcag Research Institute of DU CASE since 2001. Our organic farming activities were enhanced with sheep farming and
grassland management in 2005. We started our study of technology development of organic lamb fattening and the treatment of its economic effect this year. Our goal was to develop
the elements of the technology to reach a more efficient organic lamb fattening. We also studied what economic advantages the organic sheep farming could realize in the present economic environment. Our studies were carried out between 2005 and 2007. We established that the excellent ewe feeding (good quality of fodder and silage) can decrease the lamb feeding cost between the 2nd and 8th weeks of the lambs’ life. We established that the
yield of convention lambs are significantly higher than the yield of organic lambs. The cost of organic lamb fodder is significantly lower than the cost a convention lamb fodder, but the profit was higher in the case of convention lamb fattening. The organic lamb fattening technology (without extra price) is not competitive to the conventional lamb fattening technology. We think that the profitability of organic lamb fattening is significantly less than of the convention one. The organic lamb price should be 20-30% higher than the other price to be competitive. Unfortunatly there is only a little demand for organic lamb and there is no difference between the prices of organic and convention lambs, so organic sheep farmers have worse economic circumstances than conventional sheep farmers. -
The Role of Grasslands in the Diet of Geese
19-21Views:116A feeding trial was conducted with 4 weeks old growing geese. Feeding treatments were different proportion of chopped grass and grain pellets. Daily DM intake, weekly live weight gains and final live weight was measured. It is concluded that 25% of chopped grass in the diet has similar result as only grain pellet diet. This is good for the economy of goose production.
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Effect of fish feed containing two Chinese herbal extracts (Ganodema Iucidum and Lonicera japonica) on the non-specific immune system of Nile tilapia, Oreochromis niloticus (preliminary results)
9-14Views:131The effect of two Chinese herbs (Ganoderma lucidum and Lonicera japonica) on non-specific immune response of tilapia was examined. In addition to the control (no herbs), three diet variations were used. These contained 1.0% of Lonicera, 1.0% of Ganoderma and a mixture of Ganoderma (0.5%) and Lonicera (0.5%). The respiratory burst and phagocytic activity of blood leukocytes were monitored. Three weeks after feeding, the fish were infected with Aeromonas hydrophila. The results of this study showed that feeding tilapia with Ganoderma and Lonicera alone or in combination enhanced the phagocytosis of blood leukocytes, but not the respiratory burst activity. Both herbs, when used alone or in combination, reduced mortality after challenge with A. hydrophila. The highest mortality was observed in the control fish – 56.66%, and fish fed with Lonicera extract – 43.33% while 30% of fish died in the group fed with Ganoderma and the lowest mortality (20%) was observed when the fish were fed with a combination of the two herbs. It can be concluded that the herb extracts added to this diet act as immuno-stimulants and appear to improve the immune response and disease resistance of tilapia.
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Effect of feeds with different crude fiber content on the performance of meat goose
5-8Views:391In the last 50 years, poultry meat production has increased dynamically. The role of crude fiber content in feed is unclear based on a small amount of literature about goose feeding.
The aim of theis experiment was to determine how various crude fiber content (55; 60; 65g crude fiber/kg feed) influences the performance of meat geese in the second phase of the rearing period. 150 goslings (3 treatments, 5 cages/treatment, 10 birds/cage) were included in the test. The experiment started and finished at the age of 21st and 63rd day, respectively.
The obtained results suggest that various crude fiber content did not influence the performance of meat geese significantly; however, a feed of 55g crude fiber/kg resulted in better fattening results (final body weight, body weight gain, specific feed protein and energy conversion rate). In addition, compound feed of 65g crude fiber/kg proved more favourable with respect to cost-efficiency. Based on the obtained results so far, further models and farm experiments are required.
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HPLC-MS analysis of the active ingredients of chamomile (Matricaria chamomilla) bee feeding syrup
61-65Views:301Apiarists let prepare by bee honey products containing medicinal drugs. Our aim was to prove that the active ingredients originated from the herbs are also present in the bee products. This publication focuses only to the chamomile (Matricaria chamomilla) containing feeding syrup and the difference between the various syrup phases. To fulfil this task, we developed a method analysing the non-volatile components of the syrup using the flowers of chamomile. The method involves a filtration followed by HPLC-MS analysis. The analyses and the data evaluations proved that the non-volatile components of the herb were transferred to syrup. As the characteristic components of certain herbs could be identified also in the syrup, it is obvious that the components responsible for the medicinal effects are also transferred.
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Sensitivity of maize hybrids to common smut under field artificial inoculation conditions
25-28Views:229Common smut disease of maize is one of the most frequent diseases of crop. In the last decades the importance of disease has decreased in feeding maize production, however its importance increasing again nowadays, especially at sweet maize hybrids. The aims of this work was to find hybrids possess of resistance, and to evaluate which ones are more or less susceptible under field artificial inoculation circumstances. Among feeding maizes the less susceptible hybrid was ‘P9578’, and the most susceptible ’NK Columbia’ hybrid, and differences in cob infection between them was significant (8.8%). At sweet corn hybrids the less susceptible was ’Prelude’, while the most susceptible was ’Jumbo’ with very high significant 74.6% differences.
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The possibilities of the development of functional dairy products
33-36Views:188Because of our new aged world’s emerging stress, over exhausting and move less lifestyle the pollution, the not appropriate food consuming and the low calories in the consumed food there are more and more the called „civilian” disorders.
Many people have diabetes and osteoporosis others fight with lung, cardiovascular system, problems and find cancers of many kinds without age exemptions.
There could be a solution in changing lifestyle. In the developed side of the world there are presence of food lines with higher content in nutritious and/or vitamins and fibers such as: kalium, calcium, selen, magnesium, plus it contains less saturated fat. Because of that there is a new word in dietetics as functional foods.
Food having more inner content and/or biological values, so healthier, are called functional foods. Those foods components picked carefully for healthiness by modern knowledge of dietetics.
One of the best raw materials for functional food is the milk. It is already healthy by itself. The Körös-Maros Biofarm Ltd. has a goal of developing and marketing, health protecting organic functional foods in hungaricum products from cured milk. The Jedlik Ányos project helps the Ltd. to achieve this goal. We just finished an antioxidant test and we check if the antioxidant in present in the milk than we check the final product of the presence of the original antioxidant and the form and amount of it.
It had been feeding, for two weeks for three herd of cows selected for age, milk output and consanguinity. All of the three herd had been feeding with basic forage. One of the herds had been getting vitamin-E in the amount of 250 mg/bwkg the other group got licopin in the amount of 200 mg/bwkg once a day each by each orally, the third herd was the control group.
After two weeks we toke a sample of every herd were processed the samples into yogurt and cheese. Than we checked the raw milk, the cheese and the yogurt for antioxidant content with HPLC method. The test ended with good results by finding a great amount of antioxidant, in not only the raw milk but also in the final product. -
The effect of wool staple length on the mineral content using the same sheep feeding regime
97-100Views:276The wool of sheep is suitable to test the mineral supply; however, a number of factors could affect the results. The growth rate and length of staple can be very different according to season, physiological state and individual variation. These factors are likely to affect the quantity of minerals accumulated into the wool. Therefore, the purpose of this research was to examine whether there is a difference between the mineral content of wool nearly reached the full staple length and the freshly grown wool using the same feeding regime.
10 Tsigai pregnant sheep have been selected randomly from the same farm. Wool samples were obtained from the withers, side and quarter with bended scissors. Samples were mineralized using nitric acid and hydrogen peroxide using ultrasonic cleaning unit. P, Ca, Mg, Na, S, Cu,Se and Zn content were determined by ICP-OES. Statistical analyses were carried out by SAS (SAS Institute Inc., Cary, NC) GLM procedure.Differences between means were tested by Tukey test. Significantly lower Ca, Na, P, Zn values were found in case of intensively grown wool. Sampling location did not affect the mineral content. Herd mineral supply was adequate. Our results suggest that intensively grown wool samples have to be used for mineral analyses. -
The effects of the nanoselenium supplementation to the production parameters and the selenium retention of the red drum (Sciaenops ocellatus)
43-48Views:283The selenium is an essential trace element with antioxidant effect, constituent of many enzymes, natural component of the body of the animals. The addition to the fish feed as micro element supplementation is generally accepted. Numerous animal experiments veryfied, that the antioxidant effect of the nanoselenium is higher than other selenium forms. But no much information is available of the usuage at fish.
In the experiment were investigated the effects of the nanoselenium supplementation of a commercial fish feed were investigated to the production parameters and the body tissue composition. The correlation between the accumulated selenium content of the body and the treatment, and the feed conversation was also statistically analyzed beside the production parameters. Furthermore we were curious, if can be toxic the nanoselenium in higher doses.
The experimental stock was placed into 12 plastic tanks (each 70 l water vol.) in a recirculation system for larval rearing. The salinity and the water temperature was constant during the 8 week long experiment. The feeding was ad libitum, 4 times a day. Beside the control five (1, 1.5, 2.5, 5.5, 10.5 mg Se kg-1) duplicated treatment were set.
According to the results, from the production parameters only at the value of FCR and the survival was found significant difference (p<0.05) between the groups. However strong correlation (r=0.752–0.780, p<0.01) was determined between the treatment and the accumulated selenium levels. To analyzed the free fatty acid contentof the fish, we realized, that the selenium uptake significanly enhanced this level at all treatments. The greatest change was found in case of the type n-3 fatty acids.
Established by the results, the higher intake than 0.5 mg Se kg-1 was not changed significantly the production parameters, nevertheless to increase the selenium content of commercial feeds to 1.5 mg Se kg-1 could be rewarding on the rearing of red drum.
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Feeding Possibilities for Influencing the Fatty Acid Composition of Broiler Body
29-34Views:93The experiment was conducted to assess the effect of feeding lard, linseed oil, sunflower oil and soya oil on performance, chemical and fatty acid composition of broilers. The experiment was carried out with 1200 Ross-308 male broilers. They were fed 3 phase diets. These diets were isonitrogenous, isoenergetic and contained 6% oil. The result of the experiment shows no effect of different oil sources on growth performance in male broilers, however the fatty acid composition differed (p<0,05).
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Leaf protein analyses in order to utilise the leaf shoot of artichoke
43-47Views:163The constat growth of the Earth’s population brings with itself a higher demand for food and protein not only in human nutrition but also for the feeding of livestock. Currently, the feed industry is mainly built onseed-based protein, wherethebaseplant is soybean, which is large lycovered by imports in Hungary, similar toother European countries. However, the long-term economically sustainable lifestock breeding demandschanges which has also worked out strategies. An alternative protein sources could be green leafy plants.
In current work the Jerusalem artichokes as an alternative source of protein was studied, compared to alfalfa as a valuable protein plant. Our results indicate that fiber fraction ofJerusalem artichoke shootswas 34 to 37% after pressing in the autumn period while alfalfa slightly lower values were obtained (30%). On the other hand extracted green leaf protein concentration was higher in alfalfa than in Jerusalem artichoke. Along with this higher protein content could be measured from the leaf protein concentration of alfalfa and almost each amino acids were more, as well comparing to Jerusalem artichoke.
Overall, the alfalfa proved to be advantageous as expected both in leaf protein extraction efficiency, both regarding the content of the protein in the Jerusalem artichoke. However, considering aminoacid composition and green biomass production, Jerusalem artichokecould be a promisingplant species asplant protein sourceinthefuture.
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Effect of different lysine-metabolized energy ratio on performance of meat-type geese
39-42Views:257The aim of the experiment was to determine, how the different ratios of the digestibility lysine/ metabolized energy (0.82, 0.87, 0.91 g DLYS/MJ AMEn) of the feed influence the performance of geese. There were 150 goslings (3 treatments, 5 cages/treatments, 10 birds/cages). The experiment has started and finished at the age of 3 and 9 weeks, respectively.
The results of the experiment showed, the different ratios of DLYS/AMEn (0.82, 0.87, 0.91 g DLYS/MJ AMEn) did not influence the performance of young geese. Better growth performances were found for the 0.91 g DLYS/AMEn feed (feed intake, body weight gain, feed and energy conversion rate). This treatment coincided with high feeding costs. Based on these results we need more models and farm experiments to prove this tendency. -
Insect base-protein: A new opportunity in animal nutrition
129-138Views:533The consumption of insect protein, as well as its use in animal feeding, has become a trend. This trend is particularly receiving a lot of attention in animal nutrition because the current protein source of the highest quality in animal feeding which is fishmeal is unsustainable, expensive and its demand is higher than supply. Insect protein can be of great potential in combating world hunger as the world population continues to increase. The potential of insect protein is wide-ranging, it could improve the economics of feed production, lead to cleaner production due to its low environmental footprint.
This review focuses on the need, (nutritional and environmental) advantages of insect protein in feed production, as well as previous research findings.
The unanimous conclusion of the reviewed papers is that insect protein has a great potential in feed production in terms of nutritional value, environmental implication, sustainability as well as economic implication.
However, there is a need for the intensification of research on this alternative protein source in Europe, especially in aquaculture due to the approval of 7 insect species in aquafeeds by the European Union. Another reason for the intensification is that there is still much to be done as a result of past research which shows that growth effects vary based on species and inclusion level.
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Study of the Interaction Between Common Carp (Cyprinus carpio) and Silver Crucian Carp (Carassius auratus gibelio Bloch)
9-12Views:127Some of the main questions in the fish farming are the good manuring and the success of the feeding. For the best result is very important that only those fishes take place in the fishponds what we want. It seems to be easy but difficult to do. One of the main challenges of the successful fish production in fishponds, is to rid ponds of the silver crucian carp. In the course of the experiment, carp fry were stocked in 5 nursing ponds at the same stocking rate, with different (0-, 50-, 100-, 150-, 200%) stocking rates of silver crucian carp fry, respectively. During the rearing season, weekly test fishings were made to control the growth of the fishes. At the end of the experiment, the yield/hectar and the growth rates were calculated. The experiment proved that the presence of the silver crucian carp in the fishponds causes lower growth rates and productivity in common carp. In the control pond (without silver crucian carp), the average weight of the common carp was 25 g and the yield/hectar was over 900 kg, while in the pond with the most silver crucian carp, the average weight of the common carp was 9 g and the yield/hectar was only 158 kg.
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The effect of different fat content fish feed on the production parameters and meat quality of the hybrid striped bass
33-37Views:203The interspecific ’hybrid striped bass’ is the result of cross breeding. Their offspring have got good chances of growth and tolerate extreme water temperatures and the content of dissolute oxygen more than their parents. Furthermore, they are more resistant to diseases. Therefore, the hybrid is perfectly suitable for intensive fishery production.
Our experiment lasted for seven weeks. We analysed the indices of growth and production of the hybrid as the consequence of nurturing them with two feeds of high nutritive value during this period. We examined the content of fat and of fatty acids in the flesh of these fish. There were no considerable differences in terms of weight gain, feed conversion ratio and uneven growth between the two groups, while survival was less likely among the the fish which had consumed more fat. We demonstrated, examining the flesh of the individuals which had consumed feed containing lower fat content, that it was fattier and contained more dry matter than those that had been fed of higher fat content. Besides, the content of omega-3 and omega-6 fatty acids was higher in the fish that had consumed less lipids.
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Composition and role of hoverfly (Diptera: Syrphidae) communities in an organic apple orchard
57-61Views:123The use of hoverfly (Syrphidae) larvae in biological control is gaining more attention where the damage by their prey, aphids is significant, especially in agricultural fields and orchards, where they lower the number of aphids. The present study focuses on one hand on faunistics, on the other hand on testing the different available collecting methods for later research. Collecting in an organic apple orchard near Debrecen yielded 525 specimens of Syrphidae mostly by netting but also with white tray traps. Collected species are differentiated according to their feeding (94.1% aphidophagous). The three species found in greatest numbers are Sphaerophoria scripta (Linnaeus, 1758), Melanostoma mellinum (Linnaeus, 1758) and Episyrphus balteatus (De Geer, 1776). The available information on their biology is reviewed and their potential value of hoverflies in biological control is discussed.