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Fish Food (fish + food)
Selected AbstractsConsequences of introducing the invasive amphipod Gmelinoides fasciatus into large shallow Lake Peipsi: present distribution and possible effects on fish foodJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2010K. Kangur Summary The objective of the study was to assess the effect of the Baikalian amphipod Gmelinoides fasciatus, a successful invader into Europe, as a fish food source in Lake Peipsi to where it was introduced in the 1970s. In 2002,2006, the littoral macrozoobenthos was studied along 17 transects (0.1,4 m depth, 384 quantitative samples) to determine the recent distribution of G. fasciatus and its share in the benthic community. Earlier records on the littoral macrozoobenthos from the years 1970, 1980, 1990 and 2000 were also used for comparison. Our results indicate that the invasive G. fasciatus is the dominant species (about 43% of total macrozoobenthos abundance) in the littoral zone of Lake Peipsi, while the native gammarids Gammarus lacustris and Pallasea quadrispinosa appear to be extinct and oligochaetes seem to have declined. G. fasciatus preferred hard substrates and it was mainly distributed close to water shallow beach areas (water depth <0.2 m), where its abundance reached locally up to 29 000 ind. m,2 (97% of total macrozoobenthos abundance). This distribution pattern of the invader in summer makes it mostly inaccessible for adult fish and increases its survival rate. Being highly mobile, G. fasciatus is not sensitive to water level fluctuations in shallow lakes. These behavioural characteristic increase its population success. [source] Mutual influence of protein and lipid feed content on European catfish (Silurus glanis) growthJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2004E. Has-Schön Summary We wished to determine protein and lipid content in pelleted raw fish food, necessary for optimal growth of European catfish (Silurus glanis). Experiments were set up in 20 cages, each holding 30 young catfish. Fishes in each cage received a different food combination over a 98-day period at favourable physical and chemical water conditions. Food protein content varied between 37.5 and 45%, while lipid content, added in the form of soybean oil, varied between 3 and 11%. The oil contained an adequate , -fatty acids concentration, necessary for fish growth. The main growth indicators determined at the end of experiment were total body gain, specific growth rate and feed conversion ratio. There was a high statistical difference among the experimental groups receiving variable food combinations for each growth parameter (P < 0.001). Both protein and lipid food content affected growth parameters, but in a different manner. Further analysis , percentage of change depending on lipid to protein ratio and bivariate surface analysis , allowed us to recognize the most economical combination: 39.5% protein + 9% lipid content. The addition of 9% soybean oil to the fish food reduces the necessary protein concentration by 5.5%, with resulting identical catfish growth effects. [source] Factors affecting the predation of otter (Lutra lutra) on European pond turtle (Emys orbicularis)JOURNAL OF ZOOLOGY, Issue 2 2006J. Lanszki Abstract In this case study, the ecological background of an unusual hunting behaviour was investigated, when otters Lutra lutra preyed upon European pond turtles Emys orbicularis in a Hungarian fish pond system during an 18-month period. Predation on turtle was found only during cold periods (established by spraint analysis and also by the collection of 182 turtle carcasses in 2003). The relationship was not close between fish availability and turtle consumption (rP=,0.325, P=0.19). The crude protein content of the turtle head and leg was higher than that of fish, frog and turtle body, whereas the energy content of the samples was similar. The mean body weight of the killed turtles (460 g) fell within the range of the optimal prey size of the otter. Turtles were used as cache foods by otters during extreme environmental conditions (as in the long winter), but occurred only rarely as buffer foods during moderate winter. In fish ponds, the conservation of the coexistent otter and turtle depends on pond management. The maintenance of a higher fish availability in ponds during winter makes it possible to avoid the need to acquire a proper hunting technique on turtle, indicated by the scarcity of primary fish food. [source] Growth performance, feed utilization and body composition of Dentex dentex fed on different macronutrient combinationsAQUACULTURE RESEARCH, Issue 1 2009Amalia Pérez-Jiménez Abstract Determining an adequate macronutrient balance is essential to guarantee the production success. As protein is the limiting component for fish food, the utilization of lipids or carbohydrates as partial substitutes of this nutrient is a challenge to improve its use. In order to get an approximation of the maximum levels of utilization for carbohydrates and/or lipids and determine the most adequate macronutrient to partly replace protein as the main energy source of diets for dentex (91.7 ± 1.4 g mean weight), four experimental diets with different protein:lipid:carbohydrate percentages (43/16/28, 43/24/4, 38/19/28 and 38/24/13) were tested for 13 weeks. The results indicated the possibility of using 38% of dietary protein without affecting growth performance, under the experimental conditions. There were no differences among the four diets either in most of the nutritive utilization indicators or in the body composition and haematological parameters. The influence of dietary composition was only observed in the feed intake, being higher with more dietary carbohydrates, and the hepatosomatic index and protein efficiency ratio, showing more elevated values in diets with a higher lipid level. The dentex capacity of using both carbohydrates and lipids efficiently to obtain the necessary energy for its correct growth, as well as to compensate the energetic ,vacuum' caused by the dietary protein reduction, under the assayed conditions, was confirmed. [source] Quality preservation in chilled and frozen fish products by employment of slurry ice and natural antioxidantsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2009Isabel Medina Summary Fish products are known to provide high levels of constituents important for the human diet. At the same time, wild and farmed fish species are highly perishable products, the quality and freshness of which rapidly declines post-mortem. Accordingly, efficient storage and processing technologies need to be employed to reduce postmortem quality losses until the product reaches the consumer. The present review covers recent efforts carried out on some new and advanced strategies related to chilled and frozen storage. In the first part, research concerning the use of binary systems (slurry ice) is reviewed, this focussed on the commercialisation of fresh fish products as such or to its employment as raw material for processing. Then, the application of exogenous antioxidants to ensure retention of high quality is addressed; in this part, special attention is accorded to the endogenous antioxidant content retention and to the antioxidant/pro-oxidant balance in fish foods. [source] | ||||||||||