Energy evaluation of extruded compound foods for dogs by near-infrared spectroscopy

Near-infrared reflectance spectroscopy (NIRS) was used to predictthe chemical composition, the apparent digestibility and the content ofdigestible nutrients and energy of commercial extruded compoundfoods fordogs

Estimación de la composición corporal del ganado ovino : métodos de difusión

Las necesidades nutritivas de las ovejas varían a lo largo de su ciclo reproductivo, siendo elevadas al final de la gestación y primera fase de la lactación y próximas al mantenimiento en el resto de ios periodos. Como se verá en el transcurso de este seminario (Guada, 1991) el aporte de nutrientes no se ajusta siempre a esta evolución de las necesidades, bien por razones fisiológicas, debido a la limitada capacidad de ingestión al final de la gestación e inicio de la lactación, o bien por razones de disponibilidad de alimentos como consecuencia de la variación estacional de la producción de pastos. Para amortiguar el defase entre necesidades y aporte de nutrientes, las ovejas movilizan y utilizan sus propias reservas corporales, pudiendo perder hasta el 50 % de sus reservas iipídicas durante la gestación (Russel et al., 1968) y llegar prácticamente a la deplección de grasa a mitad de la lactación (Sykes, 1974), cuando se mantienen en condiciones de explotación extensiva. Por consiguiente no se puede establecer una relación causal entre aportes y producción si no se conoce en que medida las movilizaciones de las reservas corporales contribuyen al desarrollo del feto y anexos o a la producción de leche. Para el establecimiento de estas relaciones es precisó disponer de un método fiable de estimación de la composición corporal o estado de reservas de los animales a lo largo del ciclo reproductivo

Primary gas thermometry by means of laser-absorption spectroscopy: Determination of the Boltzmann constant

We report on a new optical implementation of primary gas thermometry based on laser absorption spectrometry in the near infrared. The method consists in retrieving the Doppler broadening from highly accurate observations of the line shape of the R(12) $\nu_{1} + 2 \nu_{2}^{\phantom{1}0} + \nu_{3}$ transition in CO$_{2}$ gas at thermodynamic equilibrium. Doppler width measurements as a function of gas temperature, ranging between the triple point of water and the gallium melting point, allowed for a spectroscopic determination of the Boltzmann constant with a relative accuracy of $\sim1.6\times10^{-4}$.Comment: Submitted to Physical Review Letter

Energy evaluation of extruded compound foods for dogs by near-infrared spectroscopy

Near-infrared reflectance spectroscopy (NIRS) was used to predict the chemical composition, apparent digestibility and digestible nutrients and energy content of commercial extruded compound foods for dogs. Fifty-six foods of known chemical composition and in vivo apparent digestibility were analysed overall and 51 foods were used to predict gross energy digestibility and digestible energy content. Modified partial least square calibration models were developed for organic matter (OM), crude protein (CP), ether extract (EE), crude fibre (CF), nitrogen free extracts (NFE) and gross energy (GE) content, the apparent digestibility (OMD, CPD, EED, NFED and GED) and the digestible nutrient and energy content (DOM, DCP, DEE, DNFE and DE) of foods. The calibration equations obtained were evaluated by the standard error and the determination coefficient of cross-validation. The cross-validation coefficients of determination (R) were 0.61, 0.99, 0.91, 0.96, 0.94 and 0.92 for OM, CP, EE, CF, NFE and GE, the corresponding standard error of cross-validation (SECV) being 5.80, 3.51, 13.35, 3.64 and 16.95 g/kg dry matter (DM) and 0.29 MJ/kg DM respectively. The prediction of apparent digestibility was slightly less accurate, but NIRS prediction of digestible nutrient (g/kg DM) and DE (MJ/kg DM) gave satisfactory results, with high R (0.93, 0.97, 0.93, 0.83 and 0.93 for DOM, DCP, DEE, DNFE and DE respectively) and relatively low SECV (11.55, 6.85, 12.14 and 22.98 g/kg DM and 0.47 MJ/kg DM). It is concluded that the precision of NIRS in predicting the energy value of compound extruded foods for dogs is similar or better than by proximate analysis, as well as being faster and more accurate

ln vivo prediction of body composition from the dilution space of the deuterium oxide in two lactating Spanish dairy breed ewes

Thirteen Churra (5 forty days and 8 seventy,days after lambing) and twelve Latxa (6 forty days and 6 a hundred and twenty days after lambing) lactating dairy ewes were used to obtain predicting equations of body fat, protein and energy from the live weight and the dilution space of deuterium oxide (SD20). Ewes were injected with 0.6 gD 20/kgo f live weight in the jugular vein and blood samples were collec5te, d7, 29 and 31 hours after infusion. The D20 content of blood water was determined by infrared spectrometry, and SDZO was calculated as the ratio between the weight of the injected D20 and its predicted concentration at zero time. After the last bleeding ewes were sheared and slaughtered and the body water, fat, protein, ash and energy were chemically determined. The Churra ewes presented 2% more water and 1.7% less protein in the fat free empty body 40 days than 70 days after lambing and fat free empty body water content decreased linearly (R=-0.60) with empty body fat content. There was however a close negative relationship (R2=0.97) between the fat and water content of the fleece free body weight. Neither the breed nor the stage of lactation significantly affect this relationship. Body water was predicted from SD20 with a residual standard deviation (RSD) of approximately kg when a pool equation was considered, though for a same SD20, the Latxa ewes presented 1.76 kg more water than the Churra ewes. Body fat and energy were predicted from the live weight and measured body water with a RSD of 0.437 kg and 6.85 Mcal, respectively, when a pool equation was considered. The adjusted means of body energy differed significantly between breeds and when this effect was taken into account the RSD diminished to 3.10 Mcal. When SDZO was substituted for measured body water, the resulting RSD were 0.980 kg and 6.85 Mcal, respectively. The intercept of the prediction equation of body fat differed significantly between breeds and when this effect was taken in account the RSD decreased to 0.703 kg. The accuracy of the body protein prediction from the ewes sheared body weight (RSD=0.56k9g from the pool equation and 0.282 kg for equation taking into account the breed effect) was not improved by the inclusion of SD20 as a second predictive variable. The stage of lactation did not significantly affect any of the equations studied

The nuclear receptor LXRα controls the functional specialization of splenic macrophages.

Macrophages are professional phagocytic cells that orchestrate innate immune responses and have considerable phenotypic diversity at different anatomical locations. However, the mechanisms that control the heterogeneity of tissue macrophages are not well characterized. Here we found that the nuclear receptor LXRα was essential for the differentiation of macrophages in the marginal zone (MZ) of the spleen. LXR-deficient mice were defective in the generation of MZ and metallophilic macrophages, which resulted in abnormal responses to blood-borne antigens. Myeloid-specific expression of LXRα or adoptive transfer of wild-type monocytes restored the MZ microenvironment in LXRα-deficient mice. Our results demonstrate that signaling via LXRα in myeloid cells is crucial for the generation of splenic MZ macrophages and identify an unprecedented role for a nuclear receptor in the generation of specialized macrophage subsets