Influence of carbon source and inoculum type on anaerobic biomass adhesion on polyurethane foam in reactors fed with acid mine drainage

This paper analyzes the influence of carbon source and inoculum origin on the dynamics of biomass adhesion to an inert support in anaerobic reactors fed with acid mine drainage. Formic acid, lactic acid and ethanol were used as carbon sources. Two different inocula were evaluated: one taken from an UASB reactor and other from the sediment of a uranium mine. The values of average colonization rates and the maximum biomass concentration (C(max)) were inversely proportional to the number of carbon atoms in each substrate. The highest C(max) value (0.35 g TVS g(-1) foam) was observed with formic acid and anaerobic sludge as inoculum. Maximum colonization rates (v(max)) were strongly influenced by the type of inoculum when ethanol and lactic acid were used. For both carbon sources, the use of mine sediment as inoculum resulted in a v(max) of 0.013 g TVS g(-1) foam day(-1), whereas 0.024 g TVS g(-1) foam day(-1) was achieved with anaerobic sludge. (C) 2011 Elsevier Ltd. All rights reserved.

Digital control and integration of a 192 MW wind farm with doubly fed induction generator into the Brazilian power system

This paper reports on design of digital control for wind turbines and its relation to the quality of power fed into the Brazilian grid on connecting to it a 192 MW wind farm equipped with doubly fed induction generators. PWM converters are deployed as vector controlled regulated current voltage sources for their rotors, for independent control of both active and reactive power of those generators. Both speed control and active power control strategies are analyzed, in the search for maximum efficiency of conversion of wind kinetic energy into electric power and enhanced quality of delivered power. (C) 2009 Elsevier B.V. All rights reserved.

Growth performance and body composition of pacu Piaractus mesopotamicus (Holmberg 1887) in response to dietary protein and energy levels

Improper dietary protein and energy levels and their ratio will lead to increased fish production cost. This work evaluated effects of dietary protein : energy ratio on growth and body composition of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5 +/- 0.4 g) were fed twice a day for 10 weeks until apparent satiation with diets containing 220, 260, 300, 340 or 380 g kg-1 crude protein (CP) and 10.9, 11.7, 12.6, 13.4 or 14.2 MJ kg-1 digestible energy (DE) in a totally randomized experimental design, 5 x 5 factorial scheme (n = 3). Weight gain, specific growth rate increased and feed conversion ratio (FCR) decreased significantly (P < 0.05) when CP increased from 220 to 271, 268 and 281 g kg-1 respectively. Pacu was able to adjust feed consumption in a wide range of dietary DE concentration. Fish fed 260 CP diets showed best (P < 0.05) protein efficiency ratio and FCR with 11.7-12.6 MJ kg-1; but for the 380 CP-diets group, significant differences were observed only at 14.2 MJ kg-1 dietary energy level, suggesting that pacu favours protein as energy source. DE was the chief influence on whole body chemical composition. Minimum dietary protein requirement of pacu is 270 g kg-1, with an optimum CP : DE of 22.2 g MJ-1.

Enteric cell proliferation in newborn lambs fed bovine and ovine colostrum

The objective of this study was to investigate immunoglobulin G (IgG) and total serum protein (TP) acquisition in newborn Santa Ines lambs fed Holstein bovine or Santa Ines ovine colostrum as well as the cell proliferation rate in the animals` intestine epithelium. At 0 h and 6 h of life, 12 newborn lambs received 250 mL of bovine 1st milking colostrum (BC) and another 12 animals received 250 mL of ovine 1st milking colostrum (OC). Blood samples were collected at 0, 6, 24. and 72 h of life. Six animals were randomly slaughtered just after birth, without colostrum intake. The other animals were randomly slaughtered at 24 and 72 h. The IgG serum concentration at 6, 24 and 72 h were significantly higher for BC, 16.32 +/- 6.19; 33.80 +/- 5.68 and 27.95 +/- 5.46 mg/mL respectively, compared with OC, 11.31 +/- 6.08, 21.02 +/- 6.53 and 19.88 +/- 7.31 mg/mL BC showed higher (P < 0.05) TP values (7.29 +/- 0.87 and 6.89 +/- 0.30 g/100 mL) at 24 and 72 h in relation to OC (5.73 +/- 1.35 and 5.69 +/- 0.57 g/100 mL). At birth, the animals showed 32.52%, 45.47% and 30.60% cells in division for the duodenum, jejunum and ileum, respectively. At 24 h, the OC animals showed lower (P < 0.0001) mitotic cell percentage in the duodenum (42.12%) and ileum (35.66%) in relation to the BC animals, 46.44% and 39.74%, respectively. At 72 h, a lower (P < 0.0001) rate of proliferation was observed in the duodenum crypts of the OC animals (36.28%) compared with BC (43.18%). The results indicate that this lacteal secretion can accelerate the epithelium renovation process and can be used as an alternative source of IgG for newborn lambs. (C) 2009 Elsevier B.V. All rights reserved.

Dietary Levamisole Influenced Hematological Parameters of Juvenile Pacu, Piaractus mesopotamicus (Holmberg 1887)

Diseases outbreaks are a major concern in intensive fish farming because fish are exposed to stressors which may negatively affect their physiology. This study set out to determine effects of dietary levamisole (Levamisole HCl; SIGMA (R)) on performance and hematology of pacu, Piaractus mesopotamicus, juveniles. Fish (55.94 g) were stocked into 24 plastic aquaria (500 L; 15 fish per aquarium) and fed for 30 d with a commercial diet with 0, 50, 100, 200, 400, and 800 mg/kg levamisole, and for an extra 15 d, with a control diet in a totally randomized design trial (n = 4). Biometrical and hematological data were collected. No significant differences in growth parameters were recorded for either control or supplemented diets. Hematological parameters, such as hemoglobin, plasma glucose, white blood count (WBC), and differential leukocyte count were influenced (P < 0.05) levamisole. WBC, lymphocytes, neutrophils, monocytes, eosinophils, and special granulocytic cell numbers decreased significantly after 15 d. Dietary levamisole at 100 mg/kg diet for 15 d increased leukocyte production in juvenile pacu. However, levamisole administration for more than 15 d presented toxicity to lymphopoietic tissues. Information about long-period administration, mode of action in weight gain, effects on hematology of levamisole in freshwater fish nutrition are scarce and necessary for its safe use in aquaculture.

Dietary lysine requirement of juvenile pacu Piaractus mesopotamicus (Holmberg, 1887)

Lysine is the reference essential amino acid in fish feeds and usually the most limiting amino acid in feedstuffs. The dietary lysine requirement of juvenile pacu Piaractus mesopotamicus (4.3 g) was determined using five isonitrogenous (32% CP) test diets containing graded levels of lysine (0.9, 1.17, 1.44, 1.69 and 1.96% of dry diet) fed three times a day to four groups of 18 fish for 74 days. Growth, body composition, nutrient retention and hematological parameters of pacu were analyzed. Analysis of variance showed that all growth performance parameters were significantly affected by dietary treatments. The lysine requirements estimated using regression analysis for maximum weight gain and feed efficiency were 1.45 and 1.51% of dry diet, respectively. Nitrogen retention efficiency increased with increasing levels of dietary lysine up to 1.43% (p<0.05). Whole-body protein increased (p<0.05) and whole-body lipid decreased (p<0.05) with increasing dietary lysine level. Thus, the lysine requirement of juvenile pacu was estimated as being 1.4-1.5% of dry diet or 4.4-4.7% of dietary protein. (c) 2009 Elsevier B.V. All rights reserved.

Apparent digestibility coefficients of selected feed ingredients for dourado Salminus brasiliensis

The excellence of its flesh and fast growth makes the dourado, Salminus brasiliensis, a carnivorous fish native to the Prata basin, a potential candidate for intensive fish farming. This study evaluated the apparent digestibility coefficients (ADC) of energy and nutrients of animal and plant protein sources for the carnivorous Characin dourado S. brasiliensis. Fish (19.5 +/- 5.0 g) were stocked in plastic cages (80-L) and fed pelleted test diets containing 30% of the test ingredient [fish meal (FM), poultry by-product meal (PBM), soybean meal (SBM), and corn gluten meal (CGM) plus 70% of a reference diet (481.4 g kg(-1) of crude protein and 18.63 kJ of gross energy per gram]. After the last daily meal, cages were transferred to cylindrical, conical-bottomed aquarium (200-L) where faeces were collected by sedimentation in a refrigerated container. Except for ADC of protein and energy, all other ADC of nutrients showed significant differences (P < 0.01). ADC values were: 94.3%, 91.3%, 93.1%, and 93.5% for crude protein; 91.0%, 90.3%, 87.8%, and 88.8% for gross energy; 92.1%, 84.5%, 80.6%, and 79.3% for ash; 83.9%, 80.3%, 84.3%, and 84.6% for dry matter; 97.4%, 96.7%, 93.3%, and 91.5% for lipid for FM, PBM, SBM, and CGM, respectively. The average amino acid ADC was: 93.6%, 90.0%, 92.1%, and 92.5% of FM, PBM, SBM, and CGM, respectively. All test ingredients were efficiently used and can partially replace FM in diets for carnivorous dourado.

Feeding Dietary Mannan Oligosaccharides to Juvenile Nile Tilapis, Oreochromis niloticus, Has No Effect on Hematological Parameters and Showed Decreased Feed Consumption

Impaired immune system by environmental stressors can lead fishes to be more susceptible to diseases that limit the economic development of aquaculture systems. This study was set out to determine the effect of six levels of mannan oligosaccharides (MOS; ActiveMOS((R)); Biorigin, Lencois Paulista, Sao Paulo, Brazil) on the performance index and hematology of Nile tilapia, Oreochromis niloticus juveniles. Fish (13.62 g) were randomly distributed into 18 plastic aquaria (300 L; 20 fishes per aquarium) and fed during 45 d with a commercial diet supplemented with 0, 0.2, 0.4, 0.6, 0.8, and 1% dietary MOS, in a totally randomized design trial (n = 3); biometrical and hematological data were collected and analyzed. There were no significant differences in hematological parameters between fish fed control and MOS supplementation diets, and daily feed consumption (FC) decreased (P < 0.05) with increasing levels of dietary MOS. Dietary MOS did not increase leukocyte count and presented negative effects on FC of Nile tilapia. At 0.4% MOS supplementation, the individual weight gain was higher in absolute values but not different (P > 0.05) compared to control diet.

Hemoglobin Regeneration Efficiency in Anemic Rats: Effects on Bone Mineral Composition and Biomechanical Properties

This study reports the effects of dietary iron (Fe) deficiency and recovery on bone mineral composition and strength in anemic rats submitted to a hemoglobin (Hb) repletion assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulfate (n = 8) or ferric pyrophosphate (FP; n = 12). At final day of each period (depletion and repletion), Fe-adequate animals were also euthanized. Iron status (blood Hb, Hb Fe pool, Hb regeneration efficiency), tibia mineral concentrations (Ca, Mg, Fe, Cu, and Zn) and biomechanical properties were evaluated. Iron-deficient rats had lower tibia Fe and Mg levels and bone strength when compared to controls. Yield load and resilience were positively related to tibia Mg levels (r = 0.47, P = 0.02 and r = 0.56, P = 0.004, respectively). Iron repletion did not recover tibia Mg concentrations impaired by Fe deficiency. Moreover, bone elastic properties were negatively affected by FP consumption. In conclusion, bone mineral composition and strength were affected by Fe deficiency, whereas dietary Fe source influenced tibia Mg and resistance in the period during which rats were recovering from anemia.

EFFECT OF n-3 POLYUNSATURATED FATTY ACIDS ON OXIDATIVE STRESS IN RATS SUPPLEMENTED WITH DIFFERENT DOSES OF FISH OIL

The diet and plasma lipid patterns associated with lipid oxidation susceptibility in rats fed different doses of polyunsaturated fatty acids (n-3 PUFA) from fish oil were evaluated. Wistar rats were assigned into three groups and received diets containing 8% soybean oil (SOY), 4% soybean oil + 4% fish oil (SOY-FISH) and 8% fish oil (FISH) for 21 days. Linoleic, oleic and alpha-linolenic acids in SOY diets were substituted by myristic, palmitic, palmitoleic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in SOY-FISH and FISH diets reducing the n-6/n-3 ratio and increasing the peroxidability index (PI). Increased dietary EPA and DHA were observed in SOY-FISH and FISH plasma at the expense of linoleic and arachidonic acid levels. Saturated fatty acids, which were significantly different between the three diets (P < 0.01), were found at the same concentration in the plasma (P = 0.23). No changes were observed in oxidative stress as measured by the concentration of thiobarbituric acid reactive substances (TBARS) expressed in brain homogenates. However, TBARS concentration in the plasma of the SOY-FISH group was higher than the other two groups (P = 0.02). The major differences between these three groups were the n-3 PUFA content (0.4, 1.8 and 3.2 g/100 g diet) and the saturates/polyunsaturates ratio (0.3, 0.5 and 0.8) for SOY, SOY-FISH, and FISH groups, respectively. Thus, n-3 PUFA intake from fish oil only when followed by a decrease in saturated/polyunsaturated fatty acids ratio increased oxidative susceptibility in rats measured by plasma TBARS concentration. PRACTICAL APPLICATIONS Because fish oil intake is associated with risk reduction for cardiovascular disease, individuals are taking supplements containing a high dose of fish oil. However, there is no scientific consensus if the intake of a high dose of fish oil could increase the oxidative stress. Thus, more studies are necessary to assure the safety of this kind of supplementation.

Effects of isoflavone-supplemented soy yogurt on lipid parameters and atherosclerosis development in hypercholesterolemic rabbits: a randomized double-blind study

Background: There is increasing interest in natural treatments to control dyslipidemia and reduce the risk of cardiovascular disease. Previous studies have demonstrated the beneficial effects of soy yogurt fermented with Enterococcus faecium CRL 183 and of dietary isoflavones on the lipid profile. The purpose of the present study was to investigate the effects of isoflavone-supplemented soy yogurt, fermented with E. faecium CRL183, on lipid parameters and atherosclerosis development in rabbits with induced hypercholesterolemia. Methods: Forty-eight rabbits were randomly assigned to eight groups fed on the following diets for 60 days: C - control; IY - isoflavone-supplemented soy yogurt; H - hypercholesterolemic (1.0% cholesterol wt/wt diet); HY - hypercholesterolemic plus soy yogurt; HIY - hypercholesterolemic plus isoflavone-supplemented soy yogurt; HP - hypercholesterolemic plus placebo; HI hypercholesterolemic plus isoflavone and HE - hypercholesterolemic plus pure culture of E. faecium CRL 183. Serum lipids and autoantibodies against oxLDL (oxLDL Ab) were analyzed on days 0, 30 and 60 of the treatment and the atherosclerotic lesions were quantified at the end of the experiment. Results: Soy yogurt, soy yogurt supplemented with isoflavones and placebo promoted significant reductions in total cholesterol level (38.1%, 27.0% and 26.6%, respectively). Significant increases in serum HDL-C concentration relative to group H were detected in animals that ingested soy yogurt, with or without the isoflavone supplement (55.2%), E. faecium culture (43.3%) or placebo (35.8%). Intake of soy yogurt and soy yogurt supplemented with isoflavones prevented the rise of oxLDL Ab during the study period. The extent of atherosclerosis in the thoracic and abdominal aortas was reduced in the HIY, HY and HP groups. However, when the whole aorta was analyzed, animals treated with soy yogurt supplemented with isoflavones exhibited the greatest reduction (51.4%, P < 0.05) in atherosclerotic lesion area, compared to group H. Conclusion: Soy yogurt could be consumed as an alternative means of reducing the risk of cardiovascular disease by improving the lipid profile and inhibiting oxLDL Ab formation. Our findings also suggest that isoflavone supplementation may enhance the antiatherosclerotic effect of soy yogurt.

Dietary glutamine supplementation increases the activity of peritoneal macrophages and hemopoiesis in early-weaned mice inoculated with Mycobacterium bovis bacillus Calmette-Guerin

Infants who are breast-fed have been shown to have a lower incidence of certain infectious diseases compared with formula-fed infants. Glutamine is one of the most abundant amino acids found in maternal milk and it is essential for the function of immune system cells such as macrophages. The purpose of this study was to investigate the effect of glutamine supplementation on the function of peritoneal macrophages and on hemopoiesis in early-weaned mice inoculated with Mycobacterium bovis bacillus Calmette-Guerin (BCG). Mice were wearied at 14 d of age and distributed to 2 groups and fed either a glutamine-free diet (n = 16) or a glutamine-supplemented diet (+Gln (n = 16). Both diets were isonitrogenous (with addition of a mixture of nonessential amino acids) and isocaloric. At d 21, 2 subgroups of mice (n = 16) were intraperitoneally injected with BCG and all mice were killed at d 28. Plasma, muscle and liver glutamine concentrations and muscle glutamine synthetase activity were not affected by diet or inoculation with BCG. The +GIn diet led to increased leukocyte and lymphocyte counts in the peripheral blood (P < 0.05) and granulocyte and lymphocyte counts in the bone marrow and spleen (P < 0.05). The +GIn diet increased spreading and adhesion capacities, hydrogen peroxide, nitric oxide, and tumor necrosis factor-alpha (TNF alpha) syntheses and the phagocytic and fungicidal activity of peritoneal macrophages (P < 0.05). The interaction between the +GIn diet and BCG inoculation increased the area under the curve of interleukin (IL)-1 beta and TNF alpha syntheses (P < 0.05). In conclusion, the intake of glutamine increases the function of peritoneal macrophages and hemopoiesis in early-weaned and BCG-inoculated mice. These data have important implications for the design of breast milk substitutes for human infants.

Influence of ammonium sulphate feeding time on fed-batch Arthrospira (Spirulina) platensis cultivation and biomass composition with and without pH control

Previous work demonstrated that a mixture of NH(4)Cl and KNO(3) as nitrogen source was beneficial to fed-batch Arthrospira (Spirulina) platensis cultivation, in terms of either lower costs or higher cell concentration. On the basis of those results, this study focused on the use of a cheaper nitrogen source mixture, namely (NH(4))(2)SO(4) plus NaNO(3), varying the ammonium feeding time (T = 7-15 days), either controlling the pH by CO(2) addition or not. A. platensis was cultivated in mini-tanks at 30 degrees C, 156 mu mol photons m(-2) s(-1), and starting cell concentration of 400 mg L(-1), on a modified Schlosser medium. T = 13 days under pH control were selected as optimum conditions, ensuring the best results in terms of biomass production (maximum cell concentration of 2911 mg L(-1), cell productivity of 179 mg L(-1) d(-1) and specific growth rate of 0.77 d(-1)) and satisfactory protein and lipid contents (around 30% each). (C) 2011 Elsevier Ltd. All rights reserved.

A New Approach to Ammonium Sulphate Feeding for Fed-Batch Arthrospira (Spirulina) platensis Cultivation in Tubular Photobioreactor

Arthrospira platensis was cultivated in tubular photobioreactor using different photosynthetic photon flux densities (PPFD) and protocols of (NH(4))(2)SO(4) fed-hatch supply. Results were evaluated by variance analysis selecting maximum cell concentration (X(m)), cell productivity (P(x)), nitrogen-to-cell conversion factor (Y(X/N)) and biomass, protein and lipid contents as responses. At PPFD of 120 and 240 mu mol-photons/m(2) s, a parabolic profile of (NH(4))(2)SO(4) addition aiming at producing biomass with 7% nitrogen content ensured X(m) values (14.1 and 12.2 g/L, respectively) comparable to those obtained with NaNO(3). At PPFD of 240 mu mol-photons/m(2) s, P(x) (1.69 g/Ld) was 36% higher, although the photosynthetic efficiency (3.0%) was less than one-half that at PPFD of 120 mu mol-photons/m(2) s. Biomass was shown to be constituted by about 35% proteins and 10% lipids, without any dependence on PPFD or kind of nitrogen source. These results highlight the possible use of (NH(4))(2)SO(4) as alternative, cheap nitrogen source for A. platensis cultivation in tubular photobioreactors. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 1271-1277, 2010

Fed-batch cultivation of Arthrospira (Spirulina) platensis: Potassium nitrate and ammonium chloride as simultaneous nitrogen sources

Arthrospira platensis was cultivated in minitanks at 13 klux, using a mixture of KNO(3) and NH(4)Cl as nitrogen source. Fed-batch daily supply of NH(4)Cl at exponentially-increasing feeding rate allowed preventing ammonia toxicity and nitrogen deficiency, providing high maximum cell concentration (X(m)) and high-quality biomass (21.85 mg chlorophyll g cells(-1); 20.5% lipids; 49.8% proteins). A central composite design combined to response surface methodology was utilized to determine the relationships between responses (X(m), cell productivity and nitrogen-to-cell conversion factor) and independent variables (KNO(3) and NH(4)Cl concentrations). Under optimum conditions (15.5 mM KNO3; 14.1 mM NH(4)Cl), X(m) was 4327 mg L(-1), a value almost coincident with that obtained with only 25.4 mM KNO(3), but more than twice that obtained with 21.5 mM NH(4)Cl. A 30%-reduction of culture medium cost can be estimated when compared to KNO(3)-batch runs, thus behaving as a cheap alternative for the commercial production of this cyanobacterium. (C) 2010 Elsevier Ltd. All rights reserved.