Skin carotenoid levels in lactating dairy cows as measured using multiple spatially resolved reflection spectroscopy.

This research communication describes a pilot study measuring skin carotenoid levels of lactating dairy cows. Carotenoids are natural antioxidants, involved in cell communication and immune function, protecting against oxidative stress. They are precursors of vitamin A, important for reproduction efficiency, growth and male fertility. Therefore, easy-to-use, inexpensive methods to measure carotenoids in cattle would provide interesting data for farmers to monitor the health and nutritional status of their herds. In this study, we used a commercially available sensor based on multiple spatially resolved reflection spectroscopy (MSRRS), intended for human use, to measure the carotenoid content in bovine skin in three research herds in France, Ireland and Scotland. Carotenoid levels were measured by applying the sensor to the teat barrel, avoiding pigmented areas of skin. Mean sensor values differed significantly between herds and between diets, with pasture-based animals showing significantly higher carotenoid levels. Our results suggest that MSRRS can be used to accurately to measure skin carotenoids in cows. However, further calibration in bovines is needed to improve of the accuracy of the MSRRS sensor in cattle.

Carbohydrates molecular structure profiles in relation to nutritional characteristics of newly developed low and normal tannin faba bean varieties in dairy cows analysed by using standard methods and the vibrational molecular spectroscopy (Ft/IR-ATR).

To our knowledge, there was no study on interactive relationship between CHO molecular structure spectral profiles of newly developed cool-season adapted faba bean and nutritional characteristics in ruminants. The aim of this study was to evaluate the impact of genotypes and tannin levels on the physicochemical and nutritional characteristics of faba bean as an alternative protein and energy source for ruminants and its relation to CHO molecular structure spectral profiles using vibrational molecular spectroscopy (Ft/IR-ATR). Eight genotypes with two tannin levels (low and normal) grown at three different locations in Saskatchewan (CDC crop research fields) were analysed. Chemical analyses were performed using AOAC standards and energy was evaluated using NRC standards. Rumen degradation kinetics were determined using in situ dairy trial. Intestinal digestion was analysed by a modified three-step in vitro technique with 12 h pre-rumen incubation in dairy cows. Molecular spectral study was performed using Ft/IR-ATR, and the molecular structural features were analysed at ca. 4000-800 cm-1 using the Spectra ManagerII. CHO-related functional groups were analysed with OMNIC 7.3. The results showed low-tannin faba bean (LT) presented a highly significant difference (p < 0.05) on rumen bypass starch (BSt) compared to normal tannin faba bean (NT). On the other hand, NT had more total tract digested starch (TDST) compared to LT. No significant differences (p > 0.10) were observed for total digestible nutrients (TDN1x ), metabolizable protein (MP), feed milk value (FMV) or rumen undegraded crude protein (RUP). Results showed differences in physicochemical characteristics among faba bean varieties; however, the predicted production performance was not different within faba bean genotypes. These outcomes suggest that faba bean can be used as nutritive ingredient for dairy cattle without a significant genotype or tannin level effect on metabolic characteristics. Results from vibrational spectroscopic study showed a higher ATR-Ft/IR absorbance (p < 0.05) in NT on inherent structural CHO (STCHO), total CHO (TCHO) area and peaks (H_1015, H_1076, H_1145), and cellulosic compounds (CEC) to total CHO (TCHO) ratio. Significant correlations could be found between CHO spectral profiles and metabolic characteristics of faba bean, which indicates that structural spectral features of faba bean could be used to predict metabolic characteristics in ruminants.

Short communication: Detection of mastication speed during rumination in cattle using 3-axis, neck-mounted accelerometers and fast Fourier transfer algorithm.

There have been limited reports on mastication speed during cattle rumination. The objective of this study was to establish a method to detect mastication speed based on data obtained during rumination through the use of a 3-axis accelerometer attached to the neck. A 3-axis accelerometer was attached to 6 dry Holstein cattle. When rumination behavior was observed, the accelerometer and the high-speed camera simultaneously recorded acceleration at the neck and moving image of the head movement. Based on the number of mastication movements recorded on video, mastication speed A was calculated. Data obtained from the 3-axis accelerometer were analyzed with fast Fourier transfer algorithm and identified as mastication speed B. The vibration of the neck recorded in the accelerometer during rumination was considered as mastication movement. Using Bland-Altman plot analysis, the mean difference between mastication speed A and mastication speed B was 0.041 s/bite, and the 95% limits of agreement ranged from -0.080 to 0.161. Since mastication movement occurred periodically, it was possible to detect the movement using spectrum analysis, as mastication speed B. Although there were some differences between calculated speeds and speeds obtained from spectrum analysis, there was clinical compatibility between mastication speed A and B. This study showed the feasibility of establishing a detection method for mastication speed during rumination, which might provide a basic procedure for studying the purpose of mastication and the variable factors involved.

Visible spectroscopy on lamb fat and muscle to authenticate the duration of pasture finishing.

Pasture-based livestock systems are considered environmentally-sustainable and welfare-friendly farming systems that can meet consumer demand for good-quality produce. However, trust in products labelled as 'grass-fed' depends on the ability to reliably authenticate pasture origin. The two objectives of this study were (i) to test the ability of visible spectroscopy combined with discriminant analysis on lamb perirenal fat (PF), dorsal fat (DF) and longissimus thoracis et lumborum muscle to discriminate different durations of pasture-finishing; and (ii) to determine the timing of appearance of the pasture signature and its stabilization in these tissues. Four groups of 35 lambs were used over two years, i.e. lambs fed concentrate in-stall (L0) and lambs grazing alfalfa for 21d (L21), 42d (L42) and 63d (L63) before slaughter. No one tissue satisfactorily discriminated the four treatment groups, with ≤75% of lambs correctly classified. However, visible spectroscopy discriminated L0 from L21 + L42 + L63 lambs with an accuracy of 92.8%, 92.0%, and 85.3% lambs correctly classified on PF, DF and muscle, respectively, and discriminated L0 + L21 from L42 + L63 lambs with an accuracy of 90.1%, 76.5% and 92.3% on PF, DF and muscle, respectively. The pasture fingerprint or signature on the spectrum appeared in most lambs between 0 and 21d in PF and DF and between 0 and 42d in muscle. Pasture signature gradually stabilized with increasing time on pasture but was not entirely stabilized in any tissue within the range of grazing durations explored. These promising results need to be confirmed on larger datasets with different breeds and grazing conditions.

Measuring body composition in dogs using bioelectrical impedance spectroscopy.

Assessment of body composition is an essential aspect of veterinary canine care, particularly as prevalence of overweight and obesity in dogs is increasing. Few quantitative objective methods for body composition measurement are available for routine clinical use. Bioelectrical impedance analysis is widely used in human medicine and nutritional assessment and although it has shown promise in production animals it has not yet been adopted for companion animals. The present study validated bioimpedance spectroscopy (BIS) against the reference method of dual-energy X-ray absorptiometry. Resistivity coefficients for use in BIS were determined: ρe = 444.8 and ρi = 1477.8 ohm.cm and used to predict fat-free mass (FFM) in a cohort of 35 mixed breed dogs. Overall, FFM was predicted to within 3.5% of reference values. At an individual level, FFM was predicted within 2 standard deviations (95% confidence) of 10%. BIS provides an objective quantitative alternative to the widely used semi-quantitative body condition scoring. In addition, BIS provides estimates of body water volumes (total, extra-and intracellular), information that can be useful in fluid management. BIS is inexpensive, and simple to perform but does require brief (<5 min) sedation of the animal.

Quantitative bioimaging of copper in frozen liver specimens from cats using laser ablation-inductively coupled plasma-mass spectrometry.

OBJECTIVES: The aim of this study was to assess laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) as a tool for measuring concentrations and determining accumulation of copper in frozen liver specimens from cats. METHODS: Six frozen liver specimens were evaluated by qualitative copper staining and quantitative flame atomic absorption spectroscopy. Tissue specimens were cryo-sectioned and quantitative bioimaging of copper was performed using LA-ICP-MS. Results were compared with those obtained using conventional methods. RESULTS: Of the six specimens, only one showed positive staining for copper with rhodanine. Using flame atomic absorption spectroscopy (FAAS), one specimen showed a deficient copper level (<100 µg/g dry weight), two specimens had copper within the reference interval (RI; 150-180 µg/g) and three specimens had copper concentrations above the RI. Bioimaging from LA-ICP-MS showed inhomogeneous distribution of hepatic copper. The areas with dense copper accumulation were represented as hotspots in the liver specimens. Hepatic copper quantification by LA-ICP-MS correlated well with copper quantified by FAAS (r = 0.96, P = 0.002). CONCLUSIONS AND RELEVANCE: Our findings suggest that quantitative bioimaging by LA-ICP-MS could be used to demonstrate the distribution and concentration of copper in frozen liver specimens from cats. The distribution of copper in these specimens was inhomogeneous with dense accumulation represented as hotspots on tissue sections. A positive correlation of hepatic copper concentrations determined by LA-ICP-MS and FAAS was found. Further studies to establish an RI for hepatic copper using this technique and to further determine its clinical utility are warranted.

A comparative study of meat quality and vibrational spectroscopic properties of different chicken breeds.

Chicken breed is one of the key factors that influence meat quality. The quality attributes of breast meat from commercial broiler (CB), Thai native chicken (NC, Leung Hang Khao), and the crossbred Korat chicken (KC) were investigated via synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy, Fourier transform Raman (FT-Raman) spectroscopy, and physicochemical analysis. The protein and carbonyl contents of KC and NC meats were higher than that of CB meat, but the lipid content was lower (P < 0.05). CB meat was characterized by high moisture, lightness (L*), and presence of taste-active nucleotides, namely, inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP). Moreover, NC meat had the highest insoluble collagen and inosine contents (P < 0.05). The predominant protein secondary structures of KC and NC meats were ß-turns and random coils, whereas α-helices were mainly found in CB meat. Based on principal component analysis, the meat quality and spectra were clearly separated by breeds. The high moisture and lipid content of meat corresponded to O-H stretching (3,203 cm-1) and C-H stretching (2,854 cm-1) in the FT-Raman spectra, whereas PO2- stretching (1,240 cm-1), measured via SR-FTIR, was well correlated with the IMP content. In addition, the FT-Raman wavenumber of 934 cm-1, indicating C-C stretching, was correlated with high water-holding capacity (WHC) in KC meat. The quality of meat from slow- and fast-growing chickens significantly varies. Vibrational spectroscopy is a powerful technique that provides insightful molecular information correlated with various meat attributes.

Disparities in hepatic copper concentrations determined by atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, and digital image analysis of rhodanine-stained sections in dogs.

OBJECTIVE: To investigate disparities in hepatic copper concentrations determined by atomic absorption spectroscopy (AAS), inductively coupled plasma mass spectrometry (ICP-MS), and digital image analysis of rhodanine-stained sections. ANIMALS: 516 dogs. PROCEDURES: Medical records of dogs for which hepatic biopsy specimens had been submitted between January 1999 and December 2019 for evaluation of copper content were reviewed. Paired hepatic copper concentrations obtained with digital image analysis and AAS or ICP-MS were compared, and Spearman rank correlation coefficients were calculated to test for correlations between qualitative copper accumulation scores and hepatic copper concentrations. For dogs for which ≥ 4 rhodanine-stained hepatic sections were available, intraindividual variation in copper distribution across hepatic sections was evaluated. RESULTS: Median hepatic copper concentrations obtained with digital image analysis exceeded concentrations obtained with AAS or ICP-MS. Concentrations were also higher in older dogs (≥ 9 years vs < 9 years), dogs of breeds with a typical body weight ≥ 20 kg (44 lb), and dogs with necroinflammatory changes or uneven copper distribution. Qualitative copper accumulation scores were significantly associated with hepatic copper concentrations; however, the correlation between qualitative score and concentration obtained with digital image analysis (rs = 0.94) was higher than the correlation between qualitative score and concentration obtained with AAS (rs = 0.75) or ICP-MS (rs = 0.57). The coefficient of variation for hepatic copper concentrations obtained with digital image analysis was significantly higher for dogs with higher hepatic copper concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that spectroscopic-spectrometric analysis of hepatic biopsy specimens commonly underestimated the concentration obtained by digital image analysis of rhodanine-stained sections.

Use of bioelectrical impedance spectroscopy to provide a measure of body composition in sows.

The ability to accurately estimate fat mass and fat-free mass (FFM) has the potential to improve the way in which sow body condition can be managed in a breeding herd. Bioelectrical impedance spectroscopy (BIS) has been evaluated as a practical technique for assessment of body composition in several livestock species, but similar work is lacking in sows. Bioelectrical impedance uses population-specific algorithms that require values for the apparent resistivities of body fluids and body proportion factors. This study comprised three major aims: (i) to derive apparent resistivity coefficients for extracellular water (ECW) and intracellular water (ICW) required for validation of BIS predictions of total body water (TBW) in live sows against standard reference tracer dilution methods; (ii) to develop predictions of TBW to body composition prediction algorithms, namely FFM, by developing a body geometry correction factor (Kb) and (iii) to compare the BIS predictions of FFM against existing impedance predictors and published prediction equations for use in sows, based on physical measurements of back-fat depth and BW (P2-based predictors). Whole body impedance measurements and the determination of TBW by deuterium dilution and ECW by bromide dilution were performed on 40 Large White x Landrace sows. Mean apparent resistivity coefficients of body fluids were 431.1 Ω.cm for ECW and 1827.8 Ω.cm for ICW. Using these coefficients, TBW and ECW were over-estimated by 6.5 and 3.3%, respectively, compared to measured reference values, although these differences were not statistically different (P > 0.05). Mean Kb was 1.09 ±â€¯0.14. Fat-free mass predictions were 194.9 kg, which equates to 60.9% of total sow weight, and 183.0 kg for BIS and the deuterium dilution method, respectively. Mean differences between the predicted and measured FFM values ranged from -8.2 to 32.7%, but were not statistically different (P > 0.05). Method validation (leave-one-out procedure) revealed that mean differences between predicted and measured values were not statistically significant (P > 0.05). Of the impedance-based predictors, equivalence testing revealed that BIS displayed the lowest test bias of 11.9 kg (8.2%), although the P2-based prediction equations exhibited the lowest bias and percentage equivalence, with narrow limits of agreement. Results indicate although differences between mean predicted and measured values were not significantly different, relatively wide limits of agreement suggest BIS as an impractical option for assessing body composition in individual sows compared to the use of existing prediction equations based on BW and back fat.

Prediction of intramuscular fat in lamb by visible and near-infrared spectroscopy in an abattoir environment.

The study used visible and near-infrared spectroscopy (Vis-NIR) in a large commercial processing plant, to test a system for meat quality (intramuscular fat; IMF) data collection within a supply chain for UK lamb meat. Crossbred Texel x Scotch Mule lambs (n = 220), finished on grass on 4 farms and slaughtered across 2 months, were processed through the abattoir and cutting plant and recorded using electronic identification. Vis-NIR scanning of the cut surface of the M. longissimus lumborum produced spectral data that predicted laboratory-measured IMF% with moderate accuracy (R2 0.38-0.48). Validation of the Vis-NIR prediction equations on an independent sample of 30 lambs slaughtered later in the season, provided similar accuracy of IMF prediction (R2 0.54). Values of IMF from four different laboratory tests were highly correlated with each other (r 0.82-0.95) and with Vis-NIR predicted IMF (r 0.66-0.75). Results suggest scope to collect lamb loin IMF data from a commercial UK abattoir, to sort cuts for different customers or to feed back to breeding programmes to improve meat quality.

Reliability of visible reflectance spectroscopy in discriminating between pasture and stall-fed lambs from thin and fat-tailed sheep breeds in dry and hot environment.

Considering the additional market value of pasture meat, many authentication methods were developed to discriminate it from meat produced in conventional systems. The visible reflectance spectroscopy technique has proved its efficiency under European conditions and breeds. The present study tested the reliability of this method to discriminate between pasture-fed (P) and stall-fed (S) lambs under North African conditions and investigated the effect of feeding system (FS) (P v. S) and breed (Barbarine; Queue Fine de l'Ouest; and Noire de Thibar) on weight and colour of perirenal, subcutaneous and caudal fat. A total of 18 P and 18 S lambs were used with 6 P and 6 S lambs for each breed. The colour and the reflectance spectrum of different fat tissues were measured. The FS affected weights of all fat tissues and all colour parameters of perirenal and subcutaneous fat (P ≤ 0.01); it almost affected redness and yellowness of caudal fat (P ≤ 0.05; P ≤ 0.01). In all adipose tissues, lightness was higher and both redness and yellowness were lower for S lambs than P lambs. The breed affected weight, lightness and redness of perirenal fat and weight and redness of subcutaneous fat with significant interaction with FS for subcutaneous fat data. To discriminate P lambs from S lambs, the reflectance spectrum of perirenal, subcutaneous and caudal fat at wavelengths between 450 and 510 nm (Method 1, M1) or at wavelengths between 400 and 700 nm using partial least squares discriminative analysis as a classification method (Method 2, M2) were used. M2 yielded to a higher proportion of correctly classified lambs compared with M1 (P = 0.001). The proportion of correctly classified lambs using M2 was 76.4, 75.0 and 80.0% for perirenal, subcutaneous and caudal fat for P lambs and 83.3, 76.4 and 100.0% for S lambs. Despite lower reliability in comparisons to European researches, this study confirmed the efficiency of visible reflectance spectroscopy technique applied on perirenal fat in feeding systems authentication under North African conditions and spotted the caudal fat as a new support for better classification of fat-tailed breeds.

Electrolytes changes in mammary secretions before foaling in jennies.

No knowledge regarding the peripartum changes in mammary secretions in the jenny are presently available in literature. In the mare, instead, several studies report the role of these changes as indicators of foetal readiness for birth and impending parturition. This experiment was designed to determine calcium, sodium, potassium concentrations, and the value of sodium/potassium ratio in mammary fluids during prepartum in the jenny. Samples were daily collected by hand milking, after mammary gland size increased noticeably, from 17 Martina Franca jennies. Prepartum mammary secretions were analysed every other day between day 10 and day 2 antepartum, and then once a day from the day before to the day of parturition. Calcium concentration showed a significant increase between day 10 and day 6 antepartum and then between day 6 and days 4 and 2. Afterwards, another statistical significant increase was observed at parturition. Sodium concentration significantly decreased from day 10 to day 2 prepartum. Potassium concentration significantly increased between day 10 and day 8 before parturition, then showed a further increase at day 4, followed by none significant changes until foaling. All jennies showed a reversal in sodium/potassium ratio between 2 days antepartum and the day before. In conclusion, the evaluation of mammary fluid calcium concentrations and the reversal of sodium/potassium ratio could be used as good indicators of foetal maturity in the jenny. As far as the prediction of parturition is concerned, the reversal of sodium/potassium ratio is the best parameter, since it was detected 48-24 h before parturition in all considered animals.

Identification of offal adulteration in beef by laser induced breakdown spectroscopy (LIBS).

Minced meat is the major ingredient in sausages, beef burgers, and similar products; and thus it is the main product subjected to adulteration with meat offal. Determination of this kind of meat adulteration is crucial due to religious, economic and ethical concerns. The aim of the present study is to discriminate the beef meat and offal samples by using laser induced breakdown spectroscopy (LIBS). To this end, LIBS and multivariate data analysis were used to discriminate pure beef and offal samples qualitatively and to determine the offal mixture adulteration quantitatively. In this analysis, meat samples were frozen and LIBS analysis were performed. The results indicate that by using principal component analysis (PCA), discrimination of pure offal and offal mixture adulterated beef samples can be achieved successfully. Besides, adulteration ratio can be determined using partial least square analysis method (PLS) with 0.947 coefficient of determination (R2) and 3.8% of limit of detection (LOD) values for offal mixture adulterated beef samples.

Specificity of the peroxisome proliferation response in mussels exposed to environmental pollutants.

Peroxisome proliferation has been proposed as novel biomarker of exposure to organic pollutants in aquatic organisms. Peroxisome proliferator compounds comprise a heterogeneous group of substances known for their ability to cause massive proliferation of peroxisomes and liver carcinogenesis in sensitive species such as rodents. Recently, several marine organisms (mussels and fish) have been shown as target species of peroxisome proliferators. In the present work, we aimed to investigate the specificity of the peroxisome proliferation response in mussels. For this purpose, mussels (Mytilus edulis) were exposed for three weeks to North Sea crude oil (NSO), a mixture of NSO, alkylphenols and extra PAHs (MIX), diallylphthalate (DAP), bisphenol-A (BPA) and tetrabromodiphenylether (TBDE), or transplanted for three weeks to four stations showing different copper concentrations in a copper mine. Peroxisome proliferation was assessed by measuring the activity of the peroxisomal beta-oxidation enzyme acyl-CoA oxidase (AOX) and the volume density occupied by peroxisomes (V(VP)) in the digestive gland. Mussels exposed to NSO and MIX showed significantly increased AOX activities and V(VP) compared to control animals. Significantly higher V(VP) was also found in DAP and TBDE exposed mussels. V(VP) did not vary in mussels transplanted into a copper concentration gradient. Our results confirm the usefulness and specificity of peroxisome proliferation as a suitable biomarker of exposure to organic contaminants such as oil derived hydrocarbons, phthalate plasticizers and polybrominated flame retardants in mussels.

Monitoring glycation-induced structural and biofunctional changes in chicken immunoglobulin Y by different monosaccharides.

Chicken IgY has been applied in the food industry as an important supplement. Glycation of IgY is of special interest due to its possible influence on the structure and functionality of IgY. IgY was subjected to in vitro glycation with 4 different monosaccharides, including glucose (Glu), mannose (Man), fucose (Fuc), and fructose (Fru). The objective of this paper was to characterize the formation of IgY-sugar conjugates using ultraviolet spectra, fluorescence spectra, circular dichroism spectra, Fourier transform infrared spectra, and SDS-PAGE and differential scanning calorimetry analysis. The antigen epitopes of native and glycated IgY was determined by enzyme-linked immunosorbent assay (ELISA). The existence of broad bands in stacking gel and sample well demonstrated that reducing monosaccharides covalently bound to IgY. The secondary structure of IgY was altered from a well-defined ß-sheet structure to a random coil structure. Fluorescence spectra showed that IgY was more hydrophilic after glycation. Thermal stability of glycated IgY was remarkably increased over that of native IgY. However, ELISA results would suggest that the antigen epitopes recognized by the polyclonal antibody and overall conformation changed in the IgY molecule due to a decrease in polyclonal antibody binding to glycated IgY. Data suggested that glycation induced by reducing sugars significantly affects the structure and antigen-binding ability of IgY, which could reduce the utility of IgY in certain applications.

Body composition assessment in horses using bioimpedance spectroscopy.

Assessment of equine body composition using objective measurements is difficult owing to the large size of the animals and the costs involved. Bioelectrical impedance spectroscopy (BIS), a technique widely used for the assessment of body composition in humans, was investigated for practicality of use in horses. BIS uses algorithms that require values for the apparent resistivities of body fluids and body proportion factors (Kb), currently not available for horses. Aims of the present study were to derive resistivity coefficients and body proportion factors and to validate their use for prediction of body composition horses. Validation of coefficients and predictive power using a split-sample agreement study design using correlation and limits of agreement analysis. Whole body impedance measurements were performed on 35 standardbred horses, yearlings to 14 yr, concurrently with determination of total body water volume (TBW) by deuterium dilution and extracellular water volume (ECW) by bromide dilution. Kb was determined in an independent group of 38 mixed-breed, age, and sex horses. Mean apparent resistivity coefficients were 511.4 and 1415.9 ohm.cm for intracellular water and TBW, respectively. Mean Kb was 1.52 ± 0.1. Using these coefficients, TBW and fat-free mass could be predicted with limits of agreement (2SD) of ± 11.6%; mean fat-free mass and fat mass were under- and overestimated by 3.1% and 14.1%, respectively, compared to measured reference values although these differences were not statistically significant. BIS is a practical technique for the assessment of body composition in equids, but the relatively wide limits of agreement, particularly for fat mass, may limit its usefulness for predicting body composition in individual horses.

Comparison of visible and near infrared reflectance spectroscopy on fat to authenticate dietary history of lambs.

Since consumers are showing increased interest in the origin and method of production of their food, it is important to be able to authenticate dietary history of animals by rapid and robust methods used in the ruminant products. Promising breakthroughs have been made in the use of spectroscopic methods on fat to discriminate pasture-fed and concentrate-fed lambs. However, questions remained on their discriminatory ability in more complex feeding conditions, such as concentrate-finishing after pasture-feeding. We compared the ability of visible reflectance spectroscopy (Vis RS, wavelength range: 400 to 700 nm) with that of visible-near-infrared reflectance spectroscopy (Vis-NIR RS, wavelength range: 400 to 2500 nm) to differentiate between carcasses of lambs reared with three feeding regimes, using partial least square discriminant analysis (PLS-DA) as a classification method. The sample set comprised perirenal fat of Romane male lambs fattened at pasture (P, n = 69), stall-fattened indoors on commercial concentrate and straw (S, n = 55) and finished indoors with concentrate and straw for 28 days after pasture-feeding (PS, n = 65). The overall correct classification rate was better for Vis-NIR RS than for Vis RS (99.0% v. 95.1%, P < 0.05). Vis-NIR RS allowed a correct classification rate of 98.6%, 100.0% and 98.5% for P, S and PS lambs, respectively, whereas Vis RS allowed a correct classification rate of 98.6%, 94.5% and 92.3% for P, S and PS lambs, respectively. This study suggests the likely implication of molecules absorbing light in the non-visible part of the Vis-NIR spectra (possibly fatty acids), together with carotenoid and haem pigments, in the discrimination of the three feeding regimes.

Element composition and biochemical components of Dirofilaria immitis.

Element composition of whole canine heartworms (Dirofilaria immitis) was determined using inductively coupled argon plasma emission spectroscopy. The elements evaluated included Na, K, Ca, Mg, P, Al, B, Ba, Cu, Fe, Mn, Sr, Zn, As, and Pb. The only significant sex difference was calcium concentration which was higher in females. Amino acid analyses of body fluid revealed presence of nine essential and eight non-essential amino acids. Concentrations for male and female heartworms were not significantly different. The spectrum of amino acids was similar to that previously reported for canine plasma. Neurotransmitters or their metabolites detected in whole male and female heartworms using HPLC with electrochemical detector were epinephrine, dihydroxyphenylacetic acid, dopamine, and 5-hydroxyindoleacetic acid. Those not detected were norepinephrine, homovanillic acid, and 5-hydroxytryptamine.

Spectral analysis of respiratory noise in horses with upper airway disorders.

REASONS FOR PERFORMING STUDY: It has long been recognised that the production of abnormal respiratory sounds by horses during exercise is frequently associated with upper airway obstructions. Respiratory acoustic measurements have shown promise in investigation of upper airway disorders in man and, more recently, in horses with experimentally-induced obstructions. OBJECTIVES: To evaluate sounds from exercising horses with naturally occurring dynamic obstructions of the upper respiratory tract and to compare these with those from normal horses in order to determine whether different obstructions produce characteristic spectral patterns. METHODS: The audio signal, airflow and videoendoscopic images were recorded simultaneously during an incremental exercise test on a high-speed treadmill. RESULTS: Spectral analysis of the audio signal showed marked differences between control and clinically afflicted horses. Dorsal displacement of the soft palate was characterised by a narrow low frequency (20-80 Hz) peak during expiration. Horses with dynamic laryngeal collapse produced inspiratory sounds characterised by a broad band high frequency spectral component in the range 1.1-2.7 kHz. CONCLUSIONS AND POTENTIAL RELEVANCE: Spectral analysis of respiratory sounds in horses has potential as a diagnostic technique for field use especially when facilities for high-speed treadmill assessment are not practicable.

Prediction of lamb carcass composition by impedance spectroscopy.

The objective of this study was to compare impedance spectroscopy with resistance measurements at a single frequency (50 kHz) for the prediction of lamb carcass composition. The impedance spectrum is usually recorded by measuring the complex impedance at various frequencies (frequency domain); however, in this study, we also applied the faster and simpler measurement in the time domain (application of a current step and measurement of the voltage response). The study was carried out on 24 male, German Black-headed Mutton lambs with an average BW of 45 kg. Frequency- and time domain-based impedance measurements were collected at 20 min and 24 h postmortem with different electrode placements. Real and imaginary parts at various frequencies were calculated from the locus diagram. Left sides were dissected into lean, fat, and bone, and right sides were ground to determine actual carcass composition. Crude fat, crude protein, and moisture were chemically analyzed on ground samples. Frequency- and time domain-based measurements did not provide the same absolute impedance values; however, the high correlations (P < 0.001) between these methods for the "real parts" showed that they ranked individuals in the same order. Most of the time domain data correlated higher to carcass composition than did the frequency domain data. The real parts of impedance showed correlations between -0.37 (P > 0.05) and -0.74 (P < 0.001) to water, crude fat, lean, and fatty tissue, whereas the relations to CP were much lower (from 0.00 to -0.47, P < 0.05). Electrode placements at different locations did not substantially improve the correlations with carcass composition. The "imaginary parts" of impedance were not suitable for the prediction of carcass composition. The highest accuracy (R2 = 0.66) was reached for the estimation of crude fat percentage by a regression equation with the time domain-based impedance measured at 24 h postmortem. Furthermore, there was not a clear superiority of measurements in a wide frequency range over a single frequency measurement at 50 kHz for the prediction of carcass composition. Even though we calculated the impedance at 50 kHz based on the locus diagram, which allowed for a high precision for predicting this impedance trait, single-frequency impedance devices typically used in practice cannot record the locus diagram and, therefore, exhibit a greater amount of uncertainty.