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Feed Formulations (feed + formulations)

Distribution by Scientific Domains

Earth and Environmental Science	100%

Selected Abstracts

A feed is only as good as its ingredients , a review of ingredient evaluation strategies for aquaculture feeds

AQUACULTURE NUTRITION, Issue 1 2007
B.D. GLENCROSS
Abstract The evaluation of feed ingredients is crucial to nutritional research and feed development for aquaculture species. In evaluating ingredients for use in aquaculture feeds, there are several important knowledge components that should be understood to enable the judicious use of a particular ingredient in feed formulation. This includes information on (1) ingredient digestibilities, (2) ingredient palatability and (3) nutrient utilization and interference. Diet design, feeding strategy, faecal collection method and method of calculation all have important implications on the determination of the digestible value of nutrients from any ingredient. There are several ways in which palatability of ingredients can be assessed, usually based on variable inclusion levels of the ingredient in question in a reference diet and feeding of those diets under an apparent satietal or self-regulating feeding regimes. However, the design of the diets, the parameters of assessment and the feeding regime can all be subject to variation depending on subtleties of the experimental design. Clearly, issues relating to feed intake are the key performance criteria in palatability assessments, and it is important that such experiments maintain sufficient stringency to allow some self-discrimination of the test feeds by the fish. The ability of fish to use nutrients from the test ingredient, or defining factors that interfere with that process, is perhaps the most complex and variable part of the ingredient evaluation process. It is crucial to discriminate effects on feed intake from effects on utilization of nutrients from ingredients (for growth and other metabolic processes). To allow an increased focus on nutrient utilization by the animals, there are several experimental strategies that can be adopted, which are based on variations in diet design and feeding regime used. Other issues such as ingredient functionality, influence on immune status and effects on organoleptic qualities are also important consideration in determining the value of ingredients in aquaculture feed formulations. A key aspect to note is the need to design all experiments with sufficient experimental capacity to detect significant effects. [source]

Use of commercial fermentation products as a highly unsaturated fatty acid source in practical diets for the Pacific white shrimp Litopenaeus vannamei

AQUACULTURE RESEARCH, Issue 7 2010
Tzachi M Samocha
Abstract Removal or reduction of marine ingredients (MI) from feed formulations is critical to the sustainability of the aquaculture industry. By removing MI, diets may become limiting in several nutrients including highly unsaturated fatty acids (HUFA) such as docosahexaenoic acid (DHA) and arachidonic acid (ArA). To reduce reliance on MI in shrimp diets, two trials were conducted with Litopenaeus vannamei juveniles to determine the feasibility of using fermentation meals rich in DHA and ArA as the primary source for HUFA. A practical diet with no MI was formulated with/without DHA and ArA supplements and fed in the first trial. A diet with menhaden fish oil or a combination of plant oil with/without DHA and ArA supplements was used in the second trial. To determine whether HUFA is only needed in the early growth stages, we also fed one group a HUFA-supplemented diet to 5 g and then switched them to a HUFA-supplement-free diet. In both trials, the weights were reduced when HUFA supplements were not provided either throughout the trial or from 5 g to harvest (<16 g). These results suggest that supplementation of plant oils with DHA- and ArA-rich oils from fermented products is a viable option to replace marine fish oil for L. vannamei. [source]

Towards effective nutritional management of waste outputs in aquaculture, with particular reference to salmonid aquaculture operations

AQUACULTURE RESEARCH, Issue 5 2010
Dominique P Bureau
Abstract Long-term sustainability of many fish culture operations may be dependent on their ability to reduce their waste outputs. The release of solid wastes is mainly a function of the digestibility of various dietary components, and the release of dissolved wastes is mainly a function of the metabolism of nutrients by the fish. Consequently, simple principles of nutrition and models have been effectively used to describe, predict and manage the excretion of wastes by fish. Nutritional strategies offer a direct and effective way of managing waste output by aquaculture operations. Very significant reduction in waste outputs per unit of fish produced, notably in terms for solid and phosphorus wastes, have been achieved over the past few decades by commercial fish culture operations. Further reduction in waste outputs could be achieved through fine-tuning of feed formulations, judicious use of feed additives and processing/refining of ingredients. A better understanding of the basis of the effect of various endogenous (biological) and exogenous (dietary, environmental) factors on nutrient utilization by fish could also contribute to the development of strategies for reducing waste outputs. The present paper provides a brief overview of issues and challenges related to potential environmental impacts of wastes, and of recent progresses relative to nutritional strategies aimed at better management of the release of wastes by aquaculture operations. [source]

Interaction between diet and genetic aptitude for weight and growth in juvenile rainbow trout, Oncorhynchus mykiss (Walbaum)

AQUACULTURE RESEARCH, Issue 8 2002
J M Blanc
Abstract Samples of rainbow trout, Oncorhynchus mykiss (Walbaum) alevins from 17 independent families (full-sib-groups) were raised from the start of feeding until the age of 18 weeks post-hatching with three diets (C, G and S) differing in protein content (fish soluble protein concentrate: 84% in C, 54% in G and 44% in S) and carbohydrates (none in C, 30% glucose in G and 40% crude corn starch in S). Fish were fed to near satiation, and their body weight and growth were measured. Diet effect was highly significant (G<,C < S), as well as the familial effect. The major part of the familial variance (80,90%) was common to the three diets. However, a minor part of the familial variance was observed to be diet dependent (family × diet interaction), and was found to result mainly from relative performances with carbohydrates (G and S diets) vs. pure protein (C diet). These results indicate that genetic improvement of growth should suffer little impairment from possible changes in future feed formulations. [source]