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Main Nutrients (main + nutrient)
Selected AbstractsPHOSPHORUS BIOAVAILABILITY MONITORING BY A BIOLUMINESCENT CYANOBACTERIAL SENSOR STRAIN ,JOURNAL OF PHYCOLOGY, Issue 1 2002Osnat Gillor Phosphorus (P) is widely considered to be the main nutrient limiting the productivity of freshwater phytoplankton, but an assessment of its bioavailability in natural samples is highly complex. In an attempt to provide a novel tool for this purpose, the promoter of the alkaline phosphatase gene, phoA, from Synechococcus sp. PCC 7942 was fused to the luxAB luciferase genes of the bioluminescent bacterium Vibrio harveyi. The resulting construct was introduced into a neutral site on the Synechococcus sp. PCC 7942 genome to yield strain APL, which emitted light when inorganic P concentrations fell below 2.3 ,M. Light emission of P-deprived cells decreased rapidly upon inorganic P readdition. The reporter was demonstrated to be a sensitive tool for monitoring the bioavailability of both inorganic and organic P sources. In water samples taken from a natural freshwater environment (Lake Kinneret, Israel), the luminescence measured correlated with total dissolved phosphate concentrations. [source] Identification of gas-producing components in different varieties of Phaseolus vulgaris by in vitro fermentationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2001M Granito Abstract Phaseolus vulgaris consumption has been limited as part of the occidental diet owing to flatulence production. Raffinose, stachyose and verbascose have been shown to be the main components responsible for flatulence; however, it is thought that soluble fibre could also be involved in this phenomenon. The aim of the present study was to identify the main components of beans influencing flatus. Ten varieties of P vulgaris originating from South America were first analysed for their main nutrient and carbohydrate fractions. Three of the varieties were then fractionated to extract soluble and insoluble fibres. Various combinations of ,-galactosides and soluble and insoluble fibre fractions, in similar proportions to those contained in cooked grains, were used as substrates for in vitro fermentation studies using human faecal inoculum to determine the fermentative capacity of each of the three fractions. Considering the white varieties, total gas production and acidification of the medium were correlated with fermented organic matter from soluble fibre (R2,=,1)) and with ,-galactosides (R2,=,0.75). On the other hand, tannins present in pigmented varieties did not seem to interfere significantly in fermentation of soluble fibre. The total production of gas per gram of mixed fractions of soluble fibre and ,-galactosides in proportions found in cooked grains was lower than that expected from each substrate separately. It can be concluded that soluble fibre and ,-galactosides are good substrates for endogenous colonic flora subjected to in vitro fermentation studies and are thus responsible for flatulence induced by legume consumption. © 2001 Society of Chemical Industry [source] Yttrium oxide (Y2O3) as an inert marker in digestibility studies with dogs, blue foxes and mink fed diets containing different protein sourcesJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2007S. G. Vhile Summary The study evaluated the use of yttrium oxide (Y2O3) as an inert marker in studies of apparent total tract digestibility in dogs, blue foxes and mink. Comparison was made with total faecal collection, and use of chromic oxide (Cr2O3) as marker respectively. Four experimental diets were added 0.1 g/kg yttrium oxide and 10 g/kg chromic oxide and fed to four animals of each species. Faecal recovery of yttrium oxide was 94.4% (SEM ± 1.0), and of chromic oxide 105.8% (SEM ± 1.5). The digestibilities of dry matter, crude protein, crude fat, starch and total carbohydrates obtained by total collection and yttrium oxide as marker showed close similarity, and in most cases not significant differences, independent of species and diets. In dogs, overall digestibilities of main nutrients with chromic oxide as marker were not significantly different from overall means obtained with yttrium oxide (p > 0.05). Overall digestibility of dry matter, crude protein and total carbohydrates in blue foxes and mink was significantly higher with chromic oxide than with yttrium oxide (p < 0.05). In dogs and blue foxes, digestibilities of individual amino acids determined by use of yttrium oxide were not different from values obtained using total collection of faeces, both within diets and for overall mean (p > 0.05). Overall amino acid digestibilities in dogs determined with chromic oxide as marker were similar to corresponding figures for yttrium oxide, whereas use of chromic oxide resulted in significantly higher digestibilites for a number of amino acids compared with yttrium oxide in foxes and mink (p < 0.05). The digestibilities of most main nutrients and amino acids revealed no interaction between diet and method (p > 0.05). The study showed that yttrium oxide can be used in low concentration in the feed, and allows high accuracy of analyses and thereby precise digestibility determination. It is concluded that yttrium oxide is an alternative inert marker to chromic oxide in the studied species. [source] Influence of lipase and/or emulsifier addition on the ileal and faecal nutrient digestibility in growing pigs fed diets containing 4% animal fat,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2004NA Dierick Abstract Information on the addition of lipase and/or emulsifiers to less digestible or saturated fat sources, such as tallow or other animal fats, used in swine feeding is very limited. Therefore, in a 4 × 4 Latin square design, the effects of adding lipase (0.05% L5, microbial source) and/or an emulsifier (0.3% Lysoforte) on the apparent ileal (AID) and faecal (AFD) digestibility of the main nutrients and fatty acids in particular were studied with four ileal-cannulated growing pigs (female, initial live weight 20 kg) fed diets containing barley/soybean meal supplemented with 4% animal fat. The fat source contained 35% saturated (S) and 65% unsaturated (U) fatty acids. All diets were free of antibacterial substances (antibiotics, copper sulphate or zinc oxide beyond requirements), in order to avoid interactions between the parameters studied and the gut flora. Lipase addition did not affect the AID or AFD of fat. However, the digestibility of minor fatty acids (C6:0, C14:0) was significantly improved by lipase at both ileal and faecal level. On the other hand, lipase supplementation (P < 0.05) improved the AID of dry matter (DM) and energy as well as the AFD of DM, organic matter (OM), crude protein (CP), ash and energy. Addition of an emulsifier did not have any significant influence on the AID or AFD of fat, while the AID values of DM, OM, CP and energy as well as the AFD values of DM, OM, CP and ash were significantly (P < 0.05) improved. Adding lipase in combination with an emulsifier to the diets decreased (P < 0.05) the AID and AFD of fat, with minor effects on the AID and AFD of the non-fat components of the diet. The lack of improvement in the digestion of fat by exogenous lipase and/or emulsifier may be related to the rather high U/S ratio (0.65:0.35) of the animal fat source used and to the mode of incorporation of the emulsifier (no pre-dispersion in the fat source). Furthermore, during the trial the diets, stored at room temperature, showed a steady increase in their content of free fatty acids (to more than 700 g kg,1 fat), due to endogenous lipase activity, leaving less room for upgrading the digestion of animal fat by exogenous lipase and/or emulsifier. Copyright © 2004 Society of Chemical Industry [source] The impact of red howler monkey latrines on the distribution of main nutrients and on topsoil profiles in a tropical rain forestAUSTRAL ECOLOGY, Issue 5 2010NADIA DOS SANTOS NEVES Abstract Scarcity of organic matter and nutrients in the topsoil is a typical feature of lowland primary tropical rain forests. However, clumped defecation by vertebrate herbivore troops and further dung beetle processing may contribute to locally improve soil biological activity and plant growth. We studied the impact of clumped defecation by the red howler monkey (Alouatta seniculus), a frugivorous primate, on the vertical distribution of topsoil (0,6 cm) main nutrients and microstructures in a tropical rain forest (French Guiana). Three latrines, where monkey troops regularly defecate, were sampled, together with adjoining controls for carbon, nitrogen, phosphorus and microscopic components. The vertical distribution of C and N was affected by clumped defecation: nutrients were mostly restricted to the top 2 cm in control areas while latrines exhibited homogeneously distributed C and N, resulting in higher C and N content below 2 cm. No marked effect of defecation was registered on Olsen P. A small although significant increase in pH (0.1,0.3 pH units) and a marked increase in soil respiration (×1.5,2.5) were registered in latrines. Soil microstructures were studied by the small-volume method. Variation according to depth, site and clumped defecation was analysed by Redundancy Analysis. The three latrines were characterized by an increase in root-penetrated mineral-organic assemblages, mainly composed of recent and old earthworm faeces. The local stimulation of plant roots, microbial and earthworm activity was prominent, together with an increase in soil fertility. Consequences for the regeneration of tropical rain forests in the Amazonian basin were discussed, in the light of existing knowledge. [source] | ||||||||||