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Fish Nutrition (fish + nutrition)
Selected AbstractsA method to determine protein digestibility of microdiets for larval and early juvenile fishAQUACULTURE NUTRITION, Issue 6 2009J.M. HANSEN Abstract A method to evaluate protein quality using in vivo methods was developed for larval fish. FluoSpheres® fluorescent microspheres (10 ,m) were incorporated into two test diets, our standard zein microdiet (ZMD) and a microdiet with identical ingredients except for the replacement of high quality fish meal with the same product cooked for 24 h at 80 °C (ZMD-CF). Several trials were performed to design a reliable method to test digestibility using FluoSpheres® as a marker. The developed in vivo technique was tested on 35 days posthatch (dph) larval Atlantic cod (Gadus morhua L.) and two tropical fish species in the early juvenile stage. The method took into account loss of total protein to the faecal pellet and water column. Apparent digestibility of protein in larval cod fed ZMD was significantly higher than that of larvae fed ZMD-CF (P < 0.05). A growth study to validate differences between the two diets showed significant differences in growth and survival of larvae fed ZMD versus ZMD-CF (P < 0.05). Further validation of our results was indicated through the use of a pH-stat method using enzymes extracted from 35 dph larval cod guts. This novel technique will be advantageous for researchers to evaluate feed ingredients for larval marine fish and is adaptable to many different areas of larval fish nutrition. [source] Effects of protein-, peptide- and free amino acid-based diets in fish nutritionAQUACULTURE RESEARCH, Issue 5 2010Konrad Dabrowski In the present review, we summarize data related to the utilization of purified diets formulated with the purpose of determining the amino acid requirements in fish independent of the ontogenetic stage and the morphological characteristics of the digestive tract. Expanding present knowledge on the formulation of protein, free amino acid (FAA) and synthetic dipeptide-based diets can provide possible insights that might lead to a better understanding of the mechanism of amino acid utilization in the growth of fish. Differences exist in the utilization of protein, dipeptides or free amino acids for growth between stomach-possessing and stomachless fish with respect to their response to manipulating the proportion of protein and dipeptides in the formulas. Free amino acid-based diets are uniformly inferior. The effects of diet manipulation on indispensable FAA concentrations in the body (muscle) are not simply the result of deamination or the protein synthesis/degradation ratio. The hydroxyproline/proline ratio was confirmed to be of value in quantifying muscle collagen degradation/synthesis and can perhaps be used to quantify the amino acid requirement necessary to maximize the utilization (deposition) of dietary amino acids. In summary, indispensable amino acid requirements for maximum growth in fish can be addressed using diets formulated from protein/peptide/FAA sources. [source] Regulation of gene expression by nutritional factors in fishAQUACULTURE RESEARCH, Issue 5 2010S Panserat Abstract In the past few years, molecular tools have been increasingly used to complement basic husbandry techniques to assess the response at the whole animal or the farm level. This review aims at giving some examples from researches undertaken in fish nutrition and gene expression and, more recently, on nutrigenomics and proteomics as applied to fish nutrition and feeding. [source] Important antinutrients in plant feedstuffs for aquaculture: an update on recent findings regarding responses in salmonidsAQUACULTURE RESEARCH, Issue 3 2010Åshild Krogdahl Abstract This review presents an overview of antinutritive factors (ANFs) relevant for fish nutrition. The sources of ANFs and the possibilities of reducing the impact of ANFs are briefly mentioned. Proteinase inhibitors, lectins, saponins and oligosaccharides are given a more thorough presentation regarding mechanisms of action and the state of knowledge regarding effects on gut function in fish and upper safe dietary levels. Thereafter, selected results from recent works addressing the involvement of T cells and proteinase-activated receptors in soybean-induced enteritis are summarized. Our conclusions are as follows: we are only beginning to understand effects of ANFs in fish; strengthening of the knowledge base is urgently needed to understand the effects and to find the means to overcome or modify these effects; interactions between the effects of ANFs appear to be very important; the microbiota may modify the effects of ANFs; not only salmonids are affected; not only soybeans contain ANFs of biological importance in fish; and with increased knowledge, we can develop better diets for optimal nutrition, health and economy in aquaculture. [source] Modelling growth and body composition in fish nutrition: where have we been and where are we going?AQUACULTURE RESEARCH, Issue 2 2010André Dumas Abstract Mathematical models in fish nutrition have proven indispensable in estimating growth and feed requirements. Nowadays, reducing the environmental footprint and improving product quality of fish culture operations are of increasing interest. This review starts by examining simple models applied to describe/predict fish growth profiles and progresses towards more comprehensive concepts based on bioenergetics and nutrient metabolism. Simple growth models often lack biological interpretation and overlook fundamental properties of fish (e.g. ectothermy, indeterminate growth). In addition, these models disregard possible variations in growth trajectory across life stages. Bioenergetic models have served to predict not only fish growth but also feed requirements and waste outputs from fish culture operations. However, bioenergetics is a concept based on energy-yielding equivalence of chemicals and has significant limitations. Nutrient-based models have been introduced into the fish nutrition literature over the last two decades and stand as a more biologically sound alternative to bioenergetic models. More mechanistic models are required to expand current understanding about growth targets and nutrient utilization for biomass gain. Finally, existing models need to be adapted further to address effectively concerns regarding sustainability, product quality and body traits. [source] My 50 years in fish nutrition, 1949,99AQUACULTURE RESEARCH, Issue 8 2001J E Halver [source] | ||||||||||