Monitoring UV-accelerated alteration processes of paintings by means of hyperspectral micro-FTIR imaging and chemometrics

We explored the potential of infrared hyperspectral microimages to investigate the alteration of organic binders in pictorial layers after artificial UV light ageing. A set of paint mockups was prepared considering three different binders, namely, rabbit glue (a collagen-based proteinaceous binder), linseed oil (representative of drying oils) and egg tempera (a mixture of egg yolk and linseed oil). Four pigments (vermilion, orpiment, azurite and lead white) were considered in order to investigate the influence of pigment-binder interaction, following color changes by means of fiber optic reflectance spectroscopy (FORS). FTIR micro-images provided a representative picture of the complex and heterogeneous structure of paintings since each pixel contained the whole spectrum of the sample area from it was recorded. Principal component analysis (PCA) was used to analyze the FTIR images data in order to extract useful information about spectral changes taking place during UV induced ageing. Significant trends were observed, mainly depending on the binders and their degradation as a consequence of UV exposition in this pilot study on model samples. Several processes, such as the oxidation of proteins with the formation of carbonyl moieties and changes in amide band positions have been detected in the case of rabbit skin glue. The evaporation of linseed oil, probably due to the breakdown of the triacylglycerols, has been noticed for the binder alone but not when it was mixed with the pigments. In these cases, other spectral features depending on the pigment have been observed in the loading plots upon oxidation, namely the broadening of the carbonyl band, the appearance of carboxylic and dicarboxylic acids and the formation of metal carboxylates. For egg tempera, the main changes detected were related to the oxidation of lipidic components present in egg yolk fraction. Furthermore, in this case, the trend observed in the score graphs suggested that the presence of lead white accelerates its oxidation. It is interesting to note the major stability of the colored pigments when using this binder.

Intramammary administration of lipopolysaccharides at parturition enhances immunoglobulin concentration in goat colostrum

In newborn ruminants, transfer of passive immunity is essential to obtain protection against pathogens. This study aimed to increase the permeability of the blood-milk barrier using intramammary lipopolysaccharides (LPS) in goats at parturition to modulate colostrum composition. Twenty multiparous Majorera dairy goats were randomly allocated in one of the two experimental groups. The LPS group (n = 10) received an intramammary administration (IA) of saline (2 mL) containing 50 µg of LPS from Escherichia coli (O55:B5) in each half udder at parturition. The control group (n = 10) received an IA of saline (2 mL). Rectal temperature (RT) was recorded, and a blood sample was collected at parturition (before IA). In addition, RT was measured, and blood and colostrum/milk samples were collected on day (d) 0.125 (3 hours), 0.5 (12 hours), 1, 2, 4, 7, 15 and 30 relative to the IA. Goat plasma immunoglobulin G (IgG) and M (IgM) and serum β-hydroxybutyrate, glucose, calcium, free fatty acids, lactate dehydrogenase and total protein concentrations were determined. Colostrum and milk yields as well as chemical composition, somatic cell count (SCC), IgG and IgM concentrations were measured. The MIXED procedure (SAS 9.4) was used, and the model included the IA, time, and the interaction between both fixed effects. Statistical significance was set as P < 0.05. Goats from the LPS group showed higher RT on d 0.125, 0.5 and 4 relative to the IA compared to the control group (PIA×Time = 0.007). Goat serum biochemical variables and plasma IgG and IgM concentrations were not affected by the IA. Colostrum and milk yield as well as chemical composition were not affected by the IA, except for milk lactose percentage that was lower in the LPS group compared to the control group (4.3 ± 0.08 and 4.6 ± 0.08%, respectively PIA = 0.026). Colostrum SCC was higher in the LPS group than in the control group (3.5 ± 0.09 and 3.1 ± 0.09 cells × 106/mL, respectively; PIA = 0.011). Similarly, milk SCC increased in the LPS group compared to the control group (PIA = 0.004). The LPS group showed higher IgG (PIA = 0.044) and IgM (PIA = 0.037) concentrations on colostrum than the control group (31.9 ± 4.8 and 19.0 ± 4.8 mg/mL, 0.8 ± 0.08 and 0.5 ± 0.08 mg/mL, respectively). No differences in milk IgG and IgM concentrations between groups were observed. In conclusion, the IA of LPS at parturition increases RT, SCC and IgG and IgM concentrations in colostrum without affecting either yield or chemical composition.

Multisensor hyperspectral imaging approach for the microchemical analysis of ultramarine blue pigments

This work presents a multisensor hyperspectral approach for the characterization of ultramarine blue, a valuable historical pigment, at the microscopic scale combining the information of four analytical techniques at the elemental and molecular levels. The hyperspectral images collected were combined in a single hypercube, where the pixels of the various spectral components are aligned on top of each other. Selected spectral descriptors have been defined to reduce data dimensionality before applying unsupervised chemometric data analysis approaches. Lazurite, responsible for the blue color of the pigment, was detected as the major mineral phase present in synthetic and good quality pigments. Impurities like pyrite were detected in lower quality samples, although the clear identification of other mineral phases with silicate basis was more difficult. There is no correlation between the spatial distribution of the bands arising in the Raman spectra of natural samples in the region 1200-1850 cm-1 and any of the transition metals or rare earth elements (REE). With this information, the previous hypothesis (based on bulk analysis) attributing these bands to luminescence emissions due to impurities of these elements must be revised. We propose the consideration of CO2 molecules trapped in the cages of the aluminosilicate structure of sodalite-type. Additionally, correlation between certain Raman features and the combined presence of Ca, P, and REE, in particular Nd, was detected for the lowest quality pigment. Our results highlight the usefulness of fusing chemical images obtained via different imaging techniques to obtain relevant information on chemical structure and properties.

Feed restriction around parturition does not affect colostrum immunoglobulin G concentration in dairy fat-tailed sheep but does affect performance and blood metabolites in newborn lambs

This study aimed to investigate the effect of prepartum and postpartum feed restriction of fat-tailed dairy sheep on colostrum IgG concentration, and performance and blood metabolites of newborn fat-tailed lambs. Twenty fat-tailed dairy sheep were randomly allocated into control (Ctrl; n = 10) and feed restriction (FR; n = 10) groups. The Ctrl group received a diet that met 100% of energy requirements, both prepartum (from wk -5 to parturition) and postpartum (from parturition to wk 5). The FR group received a diet equivalent to 100, 50, 65, 80, and 100% of the energy requirements in wk -5, -4, -3, -2, and -1 relative to parturition, respectively. After parturition, the FR group received a diet equivalent to the 100, 50, 65, 80, and 100% of the energy requirements in wk 1, 2, 3, 4, and 5, respectively. At birth, lambs were assigned to their dam's experimental group. Both the Ctrl lambs (n = 10) and the FR lambs (n = 10) were allowed to suck colostrum and milk from the dams. Colostrum samples (50 mL) were collected at parturition (0 h) and then at 1, 12, 24, 36, 48, and 72 h postpartum. Blood samples were collected from all lambs before suckling colostrum (0 h) and then at 1, 12, 24, 36, 48, and 72 h after birth and weekly until the end of the experimental period (i.e., wk 5 relative to birth). The data were evaluated using the MIXED procedure of SAS (SAS Institute Inc.). The model included feed restriction, time, and the interaction feed restriction × time as fixed effects. The individual lamb was set as a repeated subject. Variables measured in colostrum and plasma were considered dependent variables, and significance was set at P < 0.05. Prepartum and postpartum feed restriction in fat-tailed dairy sheep did not affect colostrum IgG concentration. Consequently, no differences in blood IgG concentrations were observed in the lambs. In addition, the prepartum and postpartum feed restriction experienced by fat-tailed dairy sheep caused decreased body weight and milk intake in lambs from the FR group compared with the Ctrl group. Feed restriction also promoted increased concentration of blood metabolites such as triglycerides and urea in FR lambs compared with control lambs. In conclusion, prepartum and postpartum feed restriction in fat-tailed dairy sheep did not affect either colostrum IgG concentration or blood IgG concentration of the lambs. However, prepartum and postpartum feed restriction decreased lamb milk intake and, therefore, lamb body weight gain during the first 5 wk after birth.

Review: Mammary gland physiology and modulation during colostrogenesis in dairy goats

Newborn ruminants are highly dependent on the intake of high-quality colostrum immediately after birth to obtain energy and achieve an appropriate immunisation. Previous research indicates that poor management practices in the last months of gestation can lead to increased neonatal mortality rates by reducing colostrum quality among other factors. In ruminants, colostrum synthesis is a well-preserved mechanism which has been speculated to be regulated by the neuroendocrine system. However, this review aims to explore different approaches such as alternative dry-off management practices, the inclusion of different nutrients on prepartum diets, and the stimulation of the mammary gland immune response to modulate colostrogenesis and consequently, to enhance colostrum quality. Ensuring correct dry-off practices combined with controlled dietary supplementation can support mammary gland reorganisation and potentially modulate colostrogenesis. Despite positive effects on colostrum yield, the bioactive composition of colostrum seems to be irresponsive to prepartum energy, protein, and fat supplementation in dairy goats. On the other hand, mastitis has obvious negative effects on animal health; however, an experimentally induced local inflammation seems to trigger helpful modifications on the blood-milk barrier, enhancing the concentration of some immune components (i.e., immunoglobulin G and M) in goat colostrum. Yet, most research has focused on dairy cattle, leaving a significant knowledge gap on colostrogenesis in small ruminants. Therefore, future studies should focus on developing novel dry-off and dietary strategies to not only promote a healthy lactation but also to guarantee a successful colostrum synthesis.

Intramammary administration of lipopolysaccharides at parturition does not affect the transfer of passive immunity in goat kids

This study evaluated the effect of feeding colostrum obtained from an intramammary administration (IA) of LPS from Escherichia coli (O55:B5) to dairy goats at parturition, on goat kid performance, biochemical parameters (i.e., calcium, lactate dehydrogenase, glucose, total proteins, albumin, and urea) and immune status (i.e., IgG and IgM) during the first month of life. At birth, goat kids were weighted (d 0) and immediately allocated into either the LPS group (n = 15) or the control (CON) group (n = 21) based on the experimental group of the dam. At parturition, 20 multiparous dairy goats were allocated in 1 of the 2 experimental groups (LPS vs. CON). The LPS group received an IA of saline solution (2 mL) containing 50 µg of LPS in each half udder whereas goats in the CON group received an IA of saline solution (2 mL) without LPS. Goat kids were bottle-fed dam colostrum equivalent to 10% of the birth BW divided in 2 meals (i.e., at 3 and 12 h relative to birth), and then fed twice daily with milk replacer ad libitum. Individual milk intake (MI) and BW were recorded on d 7, 15, 21 and 30 of life. Blood samples were collected on d 0, 1, 2, 4, 7, 15, 21 and 30 after birth. Data were analyzed using the MIXED procedure of SAS (9.4; SAS Institute Inc.). The model included IA, time (T), and their interaction (IA × T) as fixed effects, and sex and litter size as random effects. Both groups showed similar MI, except on d 7 relative to birth as the LPS group showed higher MI than the CON group (910.5 ± 69.77 and 683.9 ± 59.64 mL, respectively; mean ± SEM). No differences in BW or rectal temperature were observed between groups, neither in plasma IgG nor IgM concentrations. Despite the IA did not affect calcium, glucose, LDH, total protein, and albumin concentrations an interaction between the IA and T was observed for urea concentration, showing the LPS group higher urea concentrations than the CON group on d 0 (20.1 ± 1.34 and 20.0 ± 1.25 mg/dL, respectively). In conclusion, feeding colostrum from goats that received an IA of LPS at parturition does not affect goat kid performance, plasma immunoglobulin concentrations and serum metabolites during the first month of life.