Intake, nutrient apparent digestibility and ruminal constituents of sheep fed diets with canola, sunflower or castor oils

The objective in this experiment was to determine the effects of feeding diets with canola, sunflower or castor oils on intake, nutrient apparent digestibility and ruminal constituents of crossbred Dorper x Santa Ines sheep. Four rumen-cannulated animals of 90.2 +/- 11.4 kg average body weight were assigned to a 4 x 4 latin square. Animals remained individually in cages for the metabolism assay and were fed diets containing roughage at 500 g/kg and concentrate based on ground corn and soybean meal also at 500 g/kg. No oil was added to the control diet, whereas the others had canola, sunflower or castor oils at 30 g/kg (DM basis). There was no difference for the intake of DM and nutrients, except for ether extract, which was greater when animals received oil. The digestibility coefficients of dry matter, organic matter, crude protein, non-fiber carbohydrates and neutral detergent fiber were not changed; however, the addition of oil increased the ether extract digestibility. The values of total digestible nutrients (TDN, g/kg of DM), digestible energy (DE, Mcal/kg of DM), TDN intake and DE intake also did not change with the addition of lipids. Concerning the ruminal constituents, the addition of vegetable oils reduced the concentrations of acetate, butyrate and total short-chain fatty acids. Adding canola, sunflower or castor oils at 30 g/kg in diets with 500 g roughage/kg and 500 g concentrate/kg does not impair the intake or digestibility of nutrients in sheep, although it reduces the concentration of short-chain fatty acids in the rumen.

Nutrients removed by Kappaphycus alvarezii (Rhodophyta, Solieriaceae) in integrated cultivation with fishes in re-circulating water

The potential of the red alga Kappaphycus alvarezii to remove nutrients was tested to treat effluents of Trachinotus carolinus fish cultivation, and the production of carrageenan in this condition was analyzed. Experiments were conducted in four tanks of 8000 L with approximately 1200 fishes of 30 g each integrated with three tanks of 100 L with 700 g of K. alvarezii, as initial biomass per tank. Seawater was re-circulated between tanks with seaweed and with fish. As a control, three tanks with seawater circulating in an open system were utilized. Seawater samples were collected daily for 10 days and concentrations of nitrate, nitrite, ammonium and phosphate were determined in the inflow and outflow water of the tanks. Significant differences between both collecting points were considered as nutrient removal by the seaweed. Growth rates and carrageenan yields were also analyzed in seaweed cultivated in seawater and in effluents. Growth rates of seaweed cultivated in tanks were lower than those obtained in open sea and in laboratory cultivation. Effluents had concentrations of nitrate and nitrite ca. 100 times higher than in the control. Maximum values of nutrient removal on effluents were: nitrate= 18.2%; nitrite =50.8%; ammonium =70.5% and phosphate =26.8%. All plants survived throughout the experimental period, but some developed ""ice-ice"", a disease associated with physiological stress. After the experimental period, some plants selected and cultivated in open sea presented higher growth rates in 40 days, indicating nutrient storage. No significant differences between carrageenan yields of K alvarezii cultivated in seawater and in the effluents were observed. Our results show that K. alvarezii can be utilized as a biofilter for fish cultivation effluents, reducing the eutrophication process and can also be processed for carrageenan production, which provides an additional benefit to the fisheries. (C) 2008 Elsevier B.V. All rights reserved.

Digestible lysine levels in diets for pigs from 24 to 50 kg under sanitary segregation

This study evaluated the relationship between digestible lysine and metabolizable energy for barrow and gilts from 24 to 50 kg. Performance, digestibility and blood profile were studied. The experimental design was of randomized blocks, with five treatments, eight replicates and two animals per experimental unit in the performance assay and four replicates and one animal per experimental unit in the digestibility assay. The blood profile was chosen at 20 random animals of each sex, with four replicates per treatment and the animal as experimental unit. The treatments were 0.80, 0.90, 1.00, 1.10 and 1.20% digestible lysine. There was a linear effect of lysine levels on weight gain and feed conversion in females and crude protein in both sexes, gross energy excreted in the urine (kcal) and digestible energy (kcal). A quadratic effect of the amino acid studied in the daily consumption of crude protein (g) in both sexes, weight gain and feed conversion of barrows, as well as the nitrogen excreted in the urine (g) and nitrogen retained, and absorbed and retained. The relationship between neutrophils and lymphocytes had quadratic responses with increasing levels of lysine. The maximum performance for the studied genotype was obtained with 0.88 and 0.91% of digestible lysine or 2.60 and 2.67 g of digestible lysine/Mcal of metabolizable energy for females and barrows, respectively, corrected for digestibility trial.

Digestible tryptophan:lysine ratio for laying hens

The objective of this study was to evaluate the requirement of digestible tryptophan for white laying hens in the production stage fed diets of different digestible tryptophan: digestible lysine ratios, as well as animal performance and histological alterations in their reproductive and digestive systems. A total of 280 white laying hens at 29 weeks of age were distributed in a completely randomized design with five treatments and seven replications with eight birds in each. The treatments consisted of a base feed, formulated with corn, soybean meal and corn gluten meal, and supplemented with the synthetic amino acids L-lysine, DL-methionine, L-threonine, L-isoleucine, L-arginine, and L-valine, so as to meet the nutritional requirements for laying hens, except for digestible tryptophan. The basal diet was supplemented with 0.00; 0.017; 0.035; 0.052; and 0.069 g/kg of L-tryptophan in substitution for corn starch with the objective of reaching the levels of 0.151; 0.167; 0.183; 0.199; and 0.215 g/kg of digestible tryptophan in the feed. For the ratio between digestible amino acids and lysine, the recommendation of Brazilian Tables for Poultry and Swine was followed, except for the digestible tryptophan: digestible lysine ratios, which were 19, 21, 23, 25 and 27 for each treatment. The variation in the digestible tryptophan: digestible lysine ratio promoted changes in performance and in the histological characteristics, improving the results. The digestible tryptophan: digestible lysine ratio of 24.5% in the feed of white laying hens in production stage promotes better animal performance and histological results.

Influence of temperature, light and nutrients on the growth rates of the macroalga Gracilaria domingensis in synthetic seawater using experimental design

In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18-26A degrees C; L, 74-162 mu mol photons m(-2) s(-1); N, 40-80 mu mol L-1; P, 8-16 mu mol L-1; and M, 1-5 nmol L-1. The optimal conditions, which resulted in a maximum growth rate of a parts per thousand yen6.4% d(-1) from 7 to 10 days of cultivation, were determined by analysis of variance (ANOVA) multivariate factorial analysis (with a 2(5) full factorial design) to be L, 74 mu mol photons m(-2) s(-1); T, 26A degrees C; N, 80 mu mol L-1; P, 8 mu mol L-1; and M, 1 nmol L-1. In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5-7.0% d(-1). The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X (L), (alpha = 0.05). On the other hand, the only significant quadratic term (X (Q)) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R (adjusted) (2) = 0.9540).

Nutrients and Nonessential Elements in Soil after 11 Years of Wastewater Irrigation

Irrigation of citrus (Citrus aurantium L. x Citrus paradise Macf.) with urban reclaimed wastewater (RWW) can be economical and conserve fresh water. However, concerns remain regarding its deleterious effects on soil quality. We investigated the ionic speciation (ISP) of RWW and potential impacts of 11 yr of irrigation with RWW on soil quality, compared with well-water (WW) irrigation. Most of nutrients (similar to 53-99%) in RWW are free ionic species and readily available for plant uptake, such as: NH4+, NO3-, K+, Ca2+, Mg2+, SO42-, H3BO3, Cl-, Fe2+, Mn2+, Zn2+, Co2+, and Ni2+, whereas more than about 80% of Cu, Cr, Pb, and Al are complexed with CO3-, OH-, and/or organic matter. The RWW irrigation increased the availability and total concentrations of nutrients and nonessential elements, and soil salinity and sodicity by two to three times compared with WW-irrigated soils. Although RWW irrigation changed many soil parameters, no difference in citrus yield was observed. The risk of negative impacts from RWW irrigation on soil quality appears to be minimal because of: (i) adequate quality of RWW, according to USEPA limits; (ii) low concentrations of metals in soil after 11 yr of irrigation with RWW; and (iii) rapid leaching of salts in RWW-irrigated soil during the rainy season.

Influence of the use of rice bran extract as a source of nutrients on xylitol production

Xylose-to-xylitol bioconversion using 2.5 or 10% (v/v) rice bran extract was performed to verify the influence of this source of nutrients on Candida guilliermondii metabolism. Semisynthetic medium (SM) and sugarcane bagasse hemicellulosic hydrolysate detoxified with ion-exchange resins (HIE) or with alteration in pH combined with adsorption onto activated charcoal (HAC) were fermented in 125 mL Erlenmeyer flasks at 30 ºC and 200 rpm for 72 hours. Activated charcoal supplemented with 2.5% (v/v) rice bran extract was fermented by C. guilliermondii in a MULTIGEN stirred tank reactor using pH 5.0 and 22.9/hour oxygen transfer volumetric coefficient. Higher values of xylitol productivity (0.70, 0.71, and 0.62 g.Lh-1) and xylose-to-xylitol conversion yield (0.71, 0.69, and 0.63 g.g-1) were obtained with 2.5% (v/v) rice bran in semisynthetic medium, ion-exchange resins, and activated charcoal, respectively. Moreover, during batch fermentation, the xylitol volumetric productivity and fermentation efficiency values obtained were 0.53 g.Lh-1 and 61.1%, respectively.

Nutrients balances and milk fatty acid profile of mid lactation dairy cows supplemented with monensin

The aim of this study was to evaluate the nutrients balance and milk fatty acids profile of dairy cows supplemented with monensin. Twelve Brazilian Holstein dairy cows were distributed into four balanced 3x3 Latin squares, and fed with the following diets: control (C), basal diet without addition of monensin, monensin 24 (M24), addition of 24mg/kg DM of monensin, and monensin 48 (M48), addition of 48mg/kg DM. The experimental diets influenced the efficiency of net energy of lactation utilization. A quadratic effect was observed for the energy balance. It was observed effect of diets on nitrogen balance. It was observed effect of monensin in the milk yield, composition and in the milk fatty acids profile. Monensin in diets of dairy cows in mid lactation, using corn silage, improved the nutrients balance and milk fatty acid profile with 24mg/kg DM.