Red meat from animals offered a grass diet increases plasma and platelet n-3 PUFA in healthy consumers.

Red meat from grass-fed animals, compared with concentrate-fed animals, contains increased concentrations of long-chain (LC) n-3 PUFA. However, the effects of red meat consumption from grass-fed animals on consumer blood concentrations of LC n-3 PUFA are unknown. The aim of the present study was to compare the effects on plasma and platelet LC n-3 PUFA status of consuming red meat produced from either grass-fed animals or concentrate-fed animals. A randomised, double-blinded, dietary intervention study was carried out for 4 weeks on healthy subjects who replaced their habitual red meat intake with three portions per week of red meat (beef and lamb) from animals offered a finishing diet of either grass or concentrate (n 20 consumers). Plasma and platelet fatty acid composition, dietary intake, blood pressure, and serum lipids and lipoproteins were analysed at baseline and post-intervention. Dietary intakes of total n-3 PUFA, as well as plasma and platelet concentrations of LC n-3 PUFA, were significantly higher in those subjects who consumed red meat from grass-fed animals compared with those who consumed red meat from concentrate-fed animals (P < 0·05). No significant differences in concentrations of serum cholesterol, TAG or blood pressure were observed between groups. Consuming red meat from grass-fed animals compared with concentrate-fed animals as part of the habitual diet can significantly increase consumer plasma and platelet LC n-3 PUFA status. As a result, red meat from grass-fed animals may contribute to dietary intakes of LC n-3 PUFA in populations where red meat is habitually consumed.

Production performance and meat quality characteristics of sheep comprising four sex-types over a range of slaughter weights produced following commercial practice.

Eighty four lambs comprising four sex-types (entire rams, castrated rams, vasectomised rams and entire ewes) were distributed equally into seven target slaughter weights (32, 36, 40, 44, 48, 52 and 56kg). All lambs were born in early spring. Dams and lambs were out on pasture until late September when they were housed and fed concentrate and hay. At birth, ram lambs were heavier than ewe lambs (P<0.01) and gained weight faster (P<0.05). The three male sex-types were similar in birth weight, growth rate and dressing out percentage (P>0.05), and were significantly lower than ewes in dressing out percentage (P<0.001). The m. longissimus dorsi (LD) from all sex-types were similar in initial pH, ultimate pH and sarcomere length (P>0.05) but differed in cooking loss and shear force (P<0.05). The LD from ewes were lower in cooking loss than those from the male sex-types (P<0.05), and recorded smaller shear force values (P<0.05). The average a(∗) values (redness) of the LD was highest in ewes and differed only from that of vasectomised rams (P<0.05). Ewes were also highest in oxymyoglobin proportion (P<0.05). Although correlations between most meat quality parameters and slaughter weight were highly significant (P<0.001) the correlation coefficients (r) were generally small.

The effect of enamel porcelain thickness on color and the ability of a shade guide to prescribe chroma.

OBJECTIVE: To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. METHODS: Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thicknesses of 0.6, 0.8 and 0.6mm, respectively. The color of each disk was measured using a spectrophotometer. Enamel porcelain was reduced in thickness to 0.3mm and porcelain disks were remeasured. RESULTS: Reducing the enamel thickness of porcelain disk specimens significantly increased L) (p<0.05), b*, metric chroma and hue angle (p<0.001). For the three shades studied (3M1, 3M2 and 3M3) L* values were not significantly different (p>0.05) and chroma increased for 3M1 with the lowest chroma to 3M3 with the highest chroma, which is in line with the shade guide specifications. Although statistically significant (p<0.001) changes in hue angle between the three shades were small (less than 3 degrees overall). The difference in chroma between the three shades 3M1, 3M2 and 3M3 was greatest for the thin enamel layer than the thick enamel layer. SIGNIFICANCE: A change in enamel thickness from 0.6 to 0.3mm resulted in a three-unit change in L* and metric chroma and a 4 degrees change in hue angle. A change in enamel porcelain thickness will have a greater effect on higher chromatic shades than those with lower chroma. The ability of the shade guide to prescribe chroma was demonstrated but this could be offset by an anomalous enamel thickness.

Intramuscular lipid and fatty acid profile of sheep comprising four sex-types and seven slaughter weights produced following commercial procedure.

The intramuscular lipid and fatty acid profiles of the m. longissimus dorsi from 84 sheep comprising four sex-types (enire ram, vasectomised ram, wether and ewe) and seven slaughter weights (32, 36, 40, 44, 48 and 52kg) were measured. Animals were reared following the commercial practice. Specifically, they were fed pasture and a concentrate diet, and age at slaughter ranged from 180 to 390 days. Differences between entire and vasectomised rams, and between wethers and ewes in intramuscular lipid content were not significant (P>0.05). However, entire and vasectomised rams were significantly lower (P<0.05) in intramuscular lipid content than ewes and wethers. Sex related differences in 14:0 (myristic acid), t18:1, c18:1, t18:2 and c18:2 proportions were not significant (P>0.05). Ewes and wethers were similar in 16:0 (palmitic acid) and 18:0 (stearic acid) proportions, but ewes contained significantly higher 16:0 and lower 18:0 proportions than entire and vasectomised rams (P<0.01). Entire and vasectomised rams recorded the highest c18:3 proportions, wethers were intermediate whilst ewes contained the lowest proportion (P<0.01). Although neither saturated fatty acid (SFA) nor monounsaturated fatty acid (MUFA) proportions varied with sex-type, vasectomised rams contained significantly higher polyunsaturated fatty acid (PUFA) proportion that the other sex-types (P<0.05). Whilst intramuscular lipid content, and 18:0 and c18:1 proportions were linearly correlated with slaughter weight (P<0.001), 14:0 and c18:3 proportions decreased quadratically with increasing slaughter weight (P<0.001). The vasectomised ram and the entire ram were similar in fatty acid profile, except the significantly higher PUFA proportion recorded by the vasectomised ram.

Interrelationships amongst carcass and meat quality characteristics of sheep.

The relationships between various carcass and meat quality characteristics of sheep were studied. Relationships were determined by regression, using data obtained from sheep belonging to a wide range of breeds, sex types and slaughter weight (32-62 kg). The chilling rate of the M. longissimus dorsi (LD) post-mortem was negatively correlated with carcass weight (r=-0.42, P<0.01), back fat thickness (r=-0.54, P<0.001) and the cooking loss of the M. infraspinatus (IS) muscle (r=-0.44, P<0.001). Correlation between chilling rate and shear force of the IS muscle was not significant, which was also the case between chilling rate and the cooking loss and shear force of the LD and M. triceps brachii muscles. A positive relationship was observed between total collagen and cooking loss (r=0.34, P<0.05) and between heat-insoluble collagen and cooking loss of the LD muscle (r=0.37, P<0.01). Generally collagen content was positively correlated with lean content and negatively with fat content. Carcass weight was significantly (P<0.001) correlated with intramuscular fat (r=0.61), moisture (r=-0.76), cooking loss (r=-0.49), shear force (r=-0.41) and hue angle (r=-0.41). Shear force was positively associated with cooking loss (r=0.42, P<0.001), but negatively with intramuscular fat content (r=-0.55, P<0.001). Cooking loss was positively correlated with moisture content (r=0.55, P<0.001).

The use of digital imaging for colour matching and communication in restorative dentistry.

OBJECTIVE: To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'. METHODS: Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3. A second shade guide was used to match the selected shades. A Nikon Coolpix 990 digital camera with Nikon SB21B ring flash was used to record the digital images of the shade tabs of the two shade guides and the images were processed using Adobe Photoshop software. A total of 27 samples (three replicates of each shade of the nine tabs selected) were matched with a digital shade guide prepared from the digital images of the second shade guide by 10 observers on a computer screen (computerised matching method). The 10 observers also matched the same shade tabs using the conventional matching method simulated in a phantom head. In addition, colour values were obtained from the digital images using Adobe Photoshop and quantified according to an internationally recognised scale as CIELAB colour values, L*,a*,b*. The relationship of the digitally derived CIELAB values to the CIELAB values obtained using a reflectance spectrophotometer was investigated. RESULTS: The cross tabulation statistical analysis showed a statistically significant difference (p<0.001) between the conventional method and the computer method with a 43% and 61.1% correct match respectively. There was also a statistically significant difference between observers in both methods (p<0.001 and p<0.04 for the conventional and computer methods respectively). A statistically significant high correlation of the CIELAB colour values were found between both colour measurement methods (p<0.001). CONCLUSION: The observers' shade matching performance was significantly better with the computer method compared with the conventional one. There was a large variation in the observers' matching ability. The digital camera can be used as a means of colour measurements in the dental clinic.

Identification of sensory attributes, instrumental and chemical measurements important for consumer acceptability of grilled lamb Longissimus lumborum.

In this study, important eating quality attributes that influence consumer liking for grilled lamb loin have been identified using preference mapping techniques. The eating quality attributes identified as driving the consumer liking of lamb loin steaks were "tenderness", "sweet flavour", "meaty aftertaste", "roast lamb flavour" and "roast lamb aftertaste". In contrast, the texture attribute "rubbery" and the flavour attributes "bitter flavour" and "bitter aftertaste" had a negative influence on consumer perceptions. Associations were observed between eating quality and a number of instrumental and chemical measurements. Warner Bratzler Shear Force showed an association with "rubbery" texture and a negative association with "tenderness" and consumer liking scores. The compounds, glucose, glucose-6-phosphate, inosine, inosine monophosphate and adenosine monophosphate were associated with the attributes, "sweet flavour","meaty aftertaste", "roast lamb flavour", "roast lamb aftertaste" and with consumer scores for liking of lamb which is probably caused by the role some of these compounds play as precursors of flavour and as taste compounds.

The measurement of thyroxine in urine using a competitive protein binding technique.

The competitive protein vinding assay for the measurement of thyroxine in blood serum was modified for the measurement of thyroxine in urine. Samples of urine of 1 to 5 ml volume containing 0 to 5 ng/ml could be assayed with 100% recovery, and above this range, up to 10 ng, recoveries were higher due to non parallelism with the standard curves. Tests carried out using porcine serum albumin indicate that results obtained by the method are not likely to be affected by proteinuria. The cross reaction with triiodothyronine was 25%. Analysis of urine samples stored at 25 degrees C gave higher values than those stored at +4 degrees C or --20 degrees C over similar periods. These increases at 25 degrees C were of the same magnitude as those obtained by acid hydrolysis of urinary thyroxine conjugates.

Investigations of the use of clay minerals and prussian blue in reducing the transfer of dietary radiocaesium to milk.

Two experiments were performed with lactating dairy cattle to assess the efficacy of clay minerals and Prussian Blue (AFCF form) in controlling the transfer of dietary radiocaesium to milk. In Experiment 1, bentonite was included in the diet at 0, 300, 600 and 900 g d-1 and the transfer of radiocaesium from silage to milk was determined. Bentonite inclusion significantly (P less than 0.001) depressed the transfer of radiocaesium to milk with no benefit in increasing the dietary inclusion above 600 g d-1 when a 73% reduction was observed. In Experiment 2, the effectiveness of bentonite (300 g d-1), clinoptilolite (300 g d-1) and Prussian Blue (3 g d-1) as dietary additives was compared. All treatments significantly (P less than 0.001) depressed the transfer of dietary radiocaesium to milk. Clinoptilolite was less effective than bentonite and both treatments were considerably less effective than Prussian Blue, the reductions being 35%, 62% and 85% respectively.

Studies on the uptake, partition and retention of ionic and fallout radiocaesium by suckling and weaned lambs.

In the first part of this study 9 one week old lambs were fed, ad libitum, a liquid milk replacer diet containing 950 Bq 137Cs kg-1, for a period of 21 days. Absorption of the 137Cs from the milk replacer was over 90% during this period. The lambs were weaned onto a silage diet and then allocated to 2 groups (A and B). Group A was fed silage contaminated with fallout radiocaesium and group B with the same silage additionally contaminated with ionic 134CsCl. After a 3 week period the diets offered were changed over between the groups. During the silage feeding period the uptake of added ionic 134Cs was approximately twice that of fallout 134Cs present in the silage. These studies highlight the difficulties in using studies with the ionic form of the isotope to predict the animals' response to fallout contaminated feed.

Studies of the transfer of dietary radiocaesium from silage to milk in dairy cows.

Four experiments were carried out to examine the transfer of radiocaesium from silage to milk by dairy cows. Three experiments assessed the effects of stage of lactation, yield and the feeding of forage only on this transfer. It was found that maximum milk radiocaesium concentrations were achieved rapidly (within 5 days) after the start of feeding contaminated silage. The transfer coefficients (Fm) were low ranging from 0.002 to 0.003 d l-1. The fourth experiment examined the effects of alternately feeding silages, of relatively high and low radiocaesium contents, on a 2 d cycle on the milk radiocaesium content. It was observed that the milk radiocaesium content changed rapidly in response to the amount of radiocaesium ingested.

The effects of prussian blue provided by indwelling rumen boli on the tissue retention of dietary radiocaesium by sheep.

A study was carried out to examine the effects of a form of Prussian Blue, provided by indwelling rumen boli, on the tissue retention of dietary radiocaesium by sheep. A single bolus providing 20-24 mg PB d-1 achieved a 42% reduction in tissue radiocaesium content. Multiple boli were not successful due to their loss from the rumen. The preparation used did not affect the health and well being of the animals.

Preliminary investigations of urinary thyroxine excretion by young pigs.

Total and unconjugated thyroxine were measured in pig urine and the effect of several forms of stress on the urinary thyroxine excretion of young pigs was investigated. There was considerable variation in the daily urinary thyroxine excretion and the rate of excretion tended to increase with age. Handling procedures used to simulate stress had little effect on thyroxine excretion rate but group penning of pigs temporarily altered thyroxine excretion rate. A diurnal variation in the excretion rate of total and unconjugated thyroxine was observed with peaks about 9.00 h, just before feeding.

The effect of the duration and type of stress on some serum enzyme levels in pigs.

The effects of blood sampling from the ear vein, jugular vein and collection on exsanguination, on serum CK, LDH, GOT and PK activities were investigated. The activities of LDH and PK were higher in ear vein vena cava samples. The effect of pre-slaughter handling was also investigated. In general there was a significant progressive increase in serum enzyme activities from farm to slaughter, although the magnitude of the change varied for different enzymes.

Oxymyoglobin formation in meat and poultry.

The rate of oxymyoglobin formation (blooming) was estimated, by reflectance spectrophotometry and depth of oxygen penetration, of beef and pork 1. dorsi and chicken breast muscles of normal ultimate pH. Although beef bloomed very rapidly when exposed to air, even at 23°C, pork muscle exhibited little evidence of oxymyoglobin formation at this temperature and no chicken muscle produced oxymyoglobin at 23°C. Even after 48 h at 5°C there was little evidence of oxymyoglobin formation in the chicken muscles although formation was evident in the pork samples. After only 24 h storage at 5°C it was apparent that both the chicken and pork muscles oxidised to produce some metmyoglobin at their surface, though the amount produced was apparently more in the chicken than the pork samples. In most chicken samples held in air at 5°C the predominant pigments were the purple reduced myoglobin and brown metmyoglobin. The implication of these observations in relation to the packaging of chicken portions is discussed.

The use of discriminant analysis for the interpretation of the reflectance spectra of irradiated porcine M. longissimus dorsi.

Slices of porcine M. longissimus dorsi were packed in overwrap packs and subjected to irradiation (0 and 5 kGy) and then stored for 7 days at 4°C. Reflectance spectra were measured on the outside surface and a freshly cut surface at 7 days post irradiation. The reflectance spectra were transformed to reflex attenuance, k/s and first and second difference spectra and subjected to discriminant analysis. Using discriminant analysis it was possible to establish a calibration equation to discriminate between the spectra of irradiated and unirradiated pork for both the outside and the inside surface. When the calibration model was used to predict the classification of new samples a 100% correct grouping was obtained for the freshly cut surface, however, for the outside surface the classification ranged from 87 to 100% correct depending on the mathematical transformation of the reflectance spectra. This shows the potential of colour measurements as a possible rapid initial screening test for the identification of irradiated pork. Evaluation of the first difference spectra to identify peak positions showed significant differences in peak positions between irradiated and unirradiated pork. The position of the peaks in the irradiated sample is discussed as lending support to the hypothesis of the carboxyhaem form as the irradiated pigment.

The effect of ionising radiation on the colour of beef, pork and lamb.

The effect of irradiation (0 and 5 kGy) of beef, pork and lamb portions in retail overwrap packs and subsequent storage at 4°C was studied in relation to colour changes. The colour of the exterior surface of beef and pork was measured on the same samples on each day of storage for up to 7 days post irradiation. On day 7 the colour of a freshly cut surface was measured. The colour of both the exterior and a freshly cut surface of lamb, in similar retail overwrap packs was measured at 2, 5 and 7 days, post irradiation, different samples being used on each day of measurement. L* values of irradiated beef increased significantly with storage and a* values for unirradiated samples decreased significantly with storage. For lamb there was a general increase in L* and h(o) values and a decrease in a*, b* and C* values with storage. Analyses of the day 7 data showed statistically significant effects for species on all CIELAB parameters. Irradiation resulted in significantly higher hue angle (h(o)) values and the a*, b* and C* values were significantly higher on the exterior than freshly cut surface. There were a number of statistically significant 2 factor and 3 factor interactions. The role of formation of a carboxyhaem pigment in the colour of irradiated meat is discussed. The problem of interpretation of pigment changes from CIELAB values is highlighted.

The effect of ionising radiation on the colour of leg and breast of poultry meat.

The effect of irradiation (0 and 5 kGy) of chicken, goose and turkey breast and leg muscles and subsequent storage at 4°C was studied in relation to colour changes. The colour of the outside surface was measured on the breast on each day of storage for up to 7 days post irradiation and for breast and leg and day 7. The colour of a freshly cut interior surface of both breast and leg was measured after 7 days storage. L* values of control and irradiated chicken, goose and turkey breast muscles changed little during storage post irradiation. The a* values for unirradiated goose breast were significantly higher than irradiated goose breast but declined to values similar to irradiated goose breast after 7 days of storage. The b* values for irradiated turkey breast were significantly higher than unirradiated turkey breast at all times post irradiation treatment. Analysis of variance was performed on the day 7 CIELAB values of breast muscle for the effects of species, surface and irradiation and their interactions. After 7 days storage a* values of poultry breast were higher on the freshly cut surface due to irradiation in all species, with decreases in hue angle due to irradiation. The a* values of leg of all species at 7 day post irradiation was significantly higher in the irradiated treatment than the controls. The results for the turkey leg indicate that this effect may be mainly due to higher a* values of the freshly cut surface. The possible role of carboxy form of the haem pigments as the irradiated pigment form is discussed.

Some observations on the absorption spectra of various myoglobin derivatives found in meat.

The three principal myoglobin states of haem pigment, oxymyoglobin, metmyoglobin reduced myoglobin, and the ferrous nitrous oxide form, nitrosomyoglobin, were prepared as pure pigments in solution. The absorbance spectra of these solutions were determined and extinction coefficients calculated. The position of the absorption peaks showed some small differences compared to published data, in particular the use of absorbance readings at 525 nm as an isobestic point for all three could be questioned. The use of mathematical transforms to first or second difference functions showed merit for the identification of mixtures of some of the myoglobin forms. The second difference function separated the broad absorbance band in the Soret region into two separate troughs, thereby resolving a mixture of oxymyoglobin and reduced myoglobin. It is suggested that based on absorption spectra, similar mathematical transforms could be applied to the interpretation of reflectance spectra of meat and meat products. Further evaluation of such mathematical transformations is required on a range of meat reflectance spectra.

The effect of increasing carcass weight of finishing boars and gilts on joint composition and meat quality.

Two hundred and eighty-eight crossbred (3/4 Landrace × 1/4 Large White) pigs, comprising equal numbers of boars and gilts, were housed in single sex groups from 50 kg liveweight to slaughter at liveweights of 92, 105, 118 and 131 kg (carcass weights of 70, 80, 90 and 100 kg). Sample joints from the left longissimus dorsi muscle were obtained at slaughter for dissection and meat quality assessment. As carcass weight increased there were significant (p<0.001) increases in eye muscle area and subcutaneous fat content. Lean content decreased (p<0.001) with increasing carcass weight while intermuscular fat content was not affected. There was a significant interaction between carcass weight and gender with % drip loss in pork from gilts at 100 kg having a higher drip loss than boars and gilts at all other weights. There were small but significant (p<0.01) reductions in ultimate pH with increasing carcass weight. Cooking loss was also reduced (p<0.001) at the heavier weights. There was no effect of carcass weight on shear force or on intramuscular fat. Dry matter (DM) and crude protein (CP) contents of m. L. dorsi increased (p<0.001) at heavier weights while sarcomere length decreased (p=0.001). Compared with boars, gilts had greater eye muscle area (p<0.05), more subcutaneous fat (p<0.001). Meat from gilts in comparison with boars had higher % DM and % CP contents (p<0.001), higher intramuscular fat content and shear force (p<0.05). It is concluded that meat quality may be improved when carcass weight is increased from 70 to 100 kg. ©