An in vitro method to determine phosphorus digestibility of rainbow trout Oncorhynchus mykiss (Walbaum) feed ingredients

An in vitro method was developed to assess the digestibility of phosphorus in 12 plant and animal feed ingredients for rainbow trout Oncorhynchus mykiss (Walbaum). The method simulates the gastrointestinal tract of the rainbow trout with regard to pH and gastrointestinal enzymes. Phosphorus solubility was measured after acid digestion (pH 3) with and without gastric enzymes, after alkaline digestion (pH 9) with and without intestinal enzymes, and after a two-step process involving acid and alkaline digestion. Commercially available digestive enzymes from mammals were compared with digestive enzymes from rainbow trout. Correlating in vitro digestibility with in vivo digestibility showed that acid digestion with both commercial enzymes ( r ²=0.98, P  < 0.05) and trout enzymes ( r ²=0.94, P  < 0.05) predicted the in vivo digestibility of animal feed ingredients. Alkaline digestion with both enzyme systems (commercial r ²=0.79; trout r ²=0.74, P  < 0.05) or without ( r ²=0.82, P  < 0.05) enzymes predicted the in vivo digestibility of ingredients from animal byproducts but not those from plant products. The in vitro digestibility with two enzyme steps (acid and alkaline) predicted in vivo digestibility of plant and animal ingredients ( r ²=0.79 for commercial enzymes and r ²=0.74 for trout enzymes) better than did one-step acid or alkaline digestion.     

Citrulline and intestinal fatty acid-binding protein: longitudinal markers of postweaning small intestinal function in pigs?

The objective of the current study was to investigate whether plasma citrulline or intestinal fatty acid-binding protein (I-FABP) concentrations might be used as longitudinal markers for small intestinal function in piglets after weaning. Plasma citrulline and I-FABP concentrations were measured longitudinally in weaned and unweaned piglets, and related to intestinal absorption values (i.e., plasma mannitol and 3-xylose concentrations in a sugar absorption test). Within each litter (n = 10), 2 piglets with a close-to-litter-average BW were selected. At 20.8 +/- 0.4 d of age, the selected piglets per litter were either weaned conventionally (CW) or remained with the sow (UNW). One day before, and 0.5, 2, 4, and 7 d after weaning of the CW piglets, the selected piglets of both groups were subjected to a sugar absorption test. After a 2-h fast, piglets were administered an oral dose of 2 mL/kg of sugar solution, containing 50 mg/kg of mannitol and 100 mg/kg of 3-xylose. One hour after administration, a blood sample was collected from a jugular vein for determination of plasma I-FABP, citrulline, mannitol, and 3-xylose concentrations. Plasma I-FABP concentration showed great variation within treatments, and no difference was observed in plasma I-FABP concentrations between the CW and UNW treatments (P = 0.63). The absorption of 3-xylose was not different between treatments (P = 0.83). Mannitol absorption, however, was less in the weaned CW piglets compared with the UNW piglets (P = 0.003), with the nadir on d 4 postweaning. Weaning also reduced plasma citrulline concentrations in the CW treatment compared with the UNW treatment (P < 0.001). On d 4 and 7 postweaning, plasma citrulline concentrations of CW piglets were less (P < 0.001 and P = 0.0013) than preweaning values. Furthermore, in the CW treatment, plasma citrulline concentrations correlated with plasma mannitol concentrations at d 4 postweaning (r = 0.89, P = 0.008) and overall (r = 0.76, P = 0.001). Based on these results, plasma citrulline concentration seems to be a possible marker for monitoring intestinal function in pigs after weaning.     

Comparison of Chemical and Physical Indices of Maturing and Ripening Pear Fruit

Physical indices of texture (shear, compression, puncture) were compared with chemical changes (soluble solids, pH, titratable acidity) during maturation and ripening of six pear varieties. The data showed no relationships between chemical and physical indices that were consistent for all varieties.     

Three-dimensional deformation measured in an alaskan glacier

Measurements of movement along 28 boreholes reveal the three-dimensional flow field in a 6 million cubic meter reach of Worthington Glacier, a temperate valley glacier located in Alaska. Sliding at the bed accounted for 60 to 70 percent of the glacier's surface motion. Strain rates in the ice were low from the surface to a depth of about 120 meters, but then increased rapidly toward the bed. Ice deformation was not affected by temporal changes in the sliding rate. The three-dimensional pattern of motion indicates that plane strain, which is often assumed by models, is a poor approximation of this viscous flow.     

Differential response of cold stored potato tubers to ethylene

The chip color of two potato varieties (Monona and Kennebec) processed directly out of 40 F storage changed in different directions after short exposure to ethylene and continued cold storage. Monona tubers produced much darker chips after ethylene treatment whereas non-enzymatic browning of Kennebec chips was considerably less after gassing. The distribution of pigmentation in chips prepared from both tubers was more uniform after ethylene treatment.     

Magnetic Field and Plasma Observations at Mars: Initial Results of the Mars Global Surveyor Mission

The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field and plasma observations throughout the near-Mars environment, from beyond the influence of Mars to just above the surface (at an altitude of approximately 100 kilometers). The solar wind interaction with Mars is in many ways similar to that at Venus and at an active comet, that is, primarily an ionospheric-atmospheric interaction. No significant planetary magnetic field of global scale has been detected to date (<2 x 10(21) Gauss-cubic centimeter), but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of Mars is reported.     

The distribution and prevalence of Theileria buffeli in cattle in Queensland

The distribution and prevalence of Thelleria buffeli in Queensland cattle were investigated using serum samples and blood films collected primarily for brucellosis surveillance and tick fever diagnosis. Serums from 8654 cattle from 357 farms throughout Queensland were examined by an indirect fluorescent antibody test for antibody to T buffeli. In addition, 347 peripheral blood films collected from 147 farms in south-eastern Queensland were examined for piroplasms of T buffeli. The overall herd and animal prevalences for T buffeli were 75% and 41%, respectively. There was significant variation among regions in both herd and animal prevalences (P less than 0.001). Herd and animal prevalences were highest in the north and east decreasing westward. The results indicate that T buffeli is more widespread in Queensland than previously thought.     

Purification and characterization of a carboxypeptidase from squid hepatopancreas (Illex illecebrosus)

The hepatopancreas of squid (Illex illecebrosus) extract contains a wide range of carboxypeptidase (CP) activities based on hydrolysis of N-CBZ-dipeptide substrates. SDS-PAGE zymograms with N-CBZ-Phe-Leu substrate revealed three activity zones (CP-I, 23 kDa; CP-II, 29 kDa; CP-III, 42 kDa). CP-I was purified 225-fold with 86.20% recovery based on N-CBZ-Ala-Phe activity by chromatography on DEAE-cellulose, gel filtration, and chromatofocusing. The purified enzyme had broad specificity toward N-CBZ-dipeptides; however, it preferred substrates with a hydrophobic amino acid at the C terminus. CP-I had greatest activity with N-CBZ-Ala-Phe (specific activity = 7104 units/mg of protein, K(m) = 0.40 mM, and physiological efficiency = 22863). CP-I had a pI of 3.4 and is a metalloprotease that is activated by Co(2+) and partially inhibited by Pefabloc, a serine protease inhibitor. With N-CBZ-Ala-Phe and Gly-Phe, it had optimum activity at pH 8 and 70 degrees C. The amino acid composition of squid CP-I is similar to that of CP A from other species.