Application of laboratory and portable attenuated total reflectance infrared spectroscopic approaches for rapid quantification of alpaca serum immunoglobulin G.

The objective of this study was to develop and compare the performance of laboratory grade and portable attenuated total reflectance infrared (ATR-IR) spectroscopic approaches in combination with partial least squares regression (PLSR) for the rapid quantification of alpaca serum IgG concentration, and the identification of low IgG (<1000 mg/dL), which is consistent with the diagnosis of failure of transfer of passive immunity (FTPI) in neonates. Serum samples (n = 175) collected from privately owned, healthy alpacas were tested by the reference method of radial immunodiffusion (RID) assay, and laboratory grade and portable ATR-IR spectrometers. Various pre-processing strategies were applied to the ATR-IR spectra that were linked to corresponding RID-IgG concentrations, and then randomly split into two sets: calibration (training) and test sets. PLSR was applied to the calibration set and calibration models were developed, and the test set was used to assess the accuracy of the analytical method. For the test set, the Pearson correlation coefficients between the IgG measured by RID and predicted by both laboratory grade and portable ATR-IR spectrometers was 0.91. The average differences between reference serum IgG concentrations and the two IR-based methods were 120.5 mg/dL and 71 mg/dL for the laboratory and portable ATR-IR-based assays, respectively. Adopting an IgG concentration <1000 mg/dL as the cut-point for FTPI cases, the sensitivity, specificity, and accuracy for identifying serum samples below this cut point by laboratory ATR-IR assay were 86, 100 and 98%, respectively (within the entire data set). Corresponding values for the portable ATR-IR assay were 95, 99 and 99%, respectively. These results suggest that the two different ATR-IR assays performed similarly for rapid qualitative evaluation of alpaca serum IgG and for diagnosis of IgG <1000 mg/dL, the portable ATR-IR spectrometer performed slightly better, and provides more flexibility for potential application in the field.

Moving from efficacy to effectiveness: red palm oil's role in preventing vitamin A deficiency.

Vitamin A deficiency is one of the most widespread nutritional deficiencies worldwide. Hundreds of millions of children and tens of millions of women living in Sub-Saharan Africa and Southeast Asia are at particularly high risk of the adverse health consequences associated with this largely preventable condition. Red palm oil comes from oil palms that are traditionally grown in tropical regions of West Africa and are now cultivated on a large-scale commercial basis in Southeast Asia. Red palm oil is the richest naturally occurring source of beta-carotene, a carotenoid that the human body can convert into usable vitamin A (retinol). This paper reviews a series of key intervention studies designed to investigate the impact of using red palm oil-based interventions to improve vitamin A status. These included studies from Africa, Asia, and Latin America in which red palm oil was used (or proposed for use) (1) as a dietary supplement, (2) as an in-home fortificant, (3) to fortify foods used for distribution in targeted supplementary feeding programs, and (4) to fortify staple food products. Overall, the results suggest that red palm oil is highly efficacious in improving vitamin A status among populations at risk of vitamin A deficiency. The time has come to move beyond trials of biological efficacy and focus on conducting operational research projects, effectiveness trials, and cost-benefit analyses that will help expand the use of red palm oil in areas where it is likely to be well accepted but remains underutilized as a dietary source of provitamin A.