A. Horcada

Meat and fat quality of unweaned lambs as affected by slaughter weight and breed.

Sixty-four male lambs of two Southern Spanish breeds, a dairy breed (Grazalema Merino) and a meat breed (Churra Lebrijana), were used to study the effects of slaughter weight and breed on meat traits and intramuscular and subcutaneous fat composition. Lambs were reared following a traditional production system without weaning and slaughtered when live weight reached 12kg (suckling) or 20kg (light). Meat from suckling lambs of both breeds had lower fat and myoglobin contents, and was more tender and had higher scores for sustained juiciness in the sensory analysis. Fat from light lambs had lower C12:0 and C14:0 levels than fat from suckling lambs. Grazalema Merino meat had higher fat and ash contents, and its fat had higher conjugated linoleic acid content than Churra Lebrijana meat.

Suckling kid breed and slaughter weight discrimination using muscle colour and visible reflectance.

Meat colour was evaluated in 141 male suckling kids from five Spanish breeds: Blanca Andaluza (BA), Blanca Celtibérica (BC), Moncaína (MO), Negra Serrana-Castiza (NE) and Pirenaica (PI). Kids were slaughtered at 7.5 and 11.5 kg. pH and colour were measured in the longissimus thoracis et lumborum muscle. pH values did not differ significantly among breeds. Lightness tended to decrease and redness to increase as weight increased. BC and NE at light weight and BC and BA at heavy weight were characterized by greater lightness, chroma and hue. At both weights MO and PI were darker and showed lower values for chroma and hue. BA at light weight and NE at heavy weight were characterized by values that were between those of the former groups for all variables. Discriminant analysis based on colour and pH correctly classified 48.9% of the kids into their breed and slaughter weight.

Fatty acid profile of three adipose depots in seven Spanish breeds of suckling kids.

Intramuscular, subcutaneous and kidney knob fat depot fatty acid profiles were studied in 104 male suckling kids from seven Spanish breeds: Blanca Andaluza, Blanca Celtibérica, Moncaína, Negra Serrana-Castiza, Pirenaica, Malagueña and Murciano-Granadina. Kids were raised in the traditional production system on mothers milk and slaughtered at around 7kg live weight. Differences were observed between dairy (Malagueña) and meat breeds (Blanca Andaluza, Blanca Celtibérica, Moncaína, Negra Serrana-Castiza, and Pirenaica). Malagueña showed higher monounsaturated and conjugated linoleic fatty acid levels than the other breeds. Highest percentages of saturated fatty acids were observed in meat breeds. For intramuscular fat depot, the range for desirable fatty acids was 66.16-72.27% was. The influence of breed on fatty acid profiles of intramuscular, subcutaneous and kidney knob fat depots studied was evident. Intramuscular fat depot is proposed as a differentiating factor between dairy and meat breed goat kids, but not between meat breed kids.

Influence of sex on cellularity and lipogenic enzymes of Spanish lamb breeds (Lacha and Rasa Aragonesa)

The effect of sex on the size and number of adipocytes and on the lipogenic enzyme activity in different fat depots in Lacha (L) and Rasa Aragonesa (RA) lambs was studied. Male and female L lambs were fed on ewe milk and were slaughtered at 25 and 24 days of age corresponding to 11·4 and 10·9 kg live weight (UN), respectively. Male and female RA lambs were weaned at 58 days (16·0 kg LW) and were then given concentrates and barley straw until slaughtered at 89 and 91 days of age corresponding to 24·5 and 23·1 kg LW, respectively. A number of parameters were studied in omental (OM), mesenteric (MES) and kidney knob and channel fat (KKCF) depots including the amount of fat, the number and size of adipocytes and the activity of the following enzymes: glycerol 3-phosphate dehydrogenase (G3PDH), fatty acid synthetase (FAS), glucose 6-phosphate dehydrogenase (G6PDH) and NADPmalate dehydrogenase (MD). In subcutaneous (SC) and intermuscular (IM) depots, all the former parameters except the adipocyte number were studied. Females of both breeds had higher amounts of adipose tissue than males in the internal fat depots (P as well as larger adipocytes, mainly in the KKCF (P and P for L and RA lambs, respectively) and OM (P in the RA lambs) depots. There were no differences between sexes in the number of adipocytes. The activity of the G3PDH enzyme was higher in females than in males in OM and SC depots (P in L lambs, and in KKCF, IM (P OM and MES (P depots in RA lambs. Thus, the sex effect on adiposity in both breeds studied involved a greater fattening of the females which was consistent with a greater hypertrophy and a higher G3PDH activity .

Southern Spain lamb types discrimination by using visible spectroscopy and basic physicochemical traits

The potential for using visible spectroscopy (400-700nm) to classify six types (breed×production system) of lamb meat was investigated. Seven wavelengths namely 400, 410, 420, 450, 510, 610 and 670nm were retained for the discriminant analysis. The basic meat physicochemical traits of Longissimus dorsi were also studied and a model including that information together with the spectra was developed to compare both accuracies. Then, Myoglobin content, water holding capacity, pH, a(∗), 670 and 610nm wavelengths, protein percentage, L(∗), ash content, 450 and 420nm wavelengths and moisture percentage were selected as variables for the development of the discriminant function. The data analysis showed that it was possible to discriminate the lamb types with accuracy around 83% using visible spectroscopy. However these results improved to 95% when using the reflectance together with basic physicochemical traits (12% better than using only the spectra).

Effect of slaughter weight and breed on instrumental and sensory meat quality of suckling kids

The effects of breed and slaughter weight on chemical composition, fatty acid groups, texture, and sensory characteristics of meat of 141 suckling male kids from 5 Spanish breeds were studied. There was a decrease in texture and lightness and hue angle with the increase of the slaughter weight. Fatty acid composition was correlated with the intramuscular fat content. All the breeds except MO had values of n-6/n-3 ratio below 4, which is the healthy limit recommended, and a low atherogenic index as well as a low intramuscular fat content. A multivariate analysis discriminated light kid, which had the most tender and juicy meat, from heavy kid which had more intense kid and milk odours. Blanca Andaluza and Pirenaica had most tender and juicy meat. The effect of slaughter weight on meat traits should be considered separately for each breed to find the most appropriate meat according to consumers preferences.

Association Study Between a SNP in Bovine SCD1 Gene with Fatty Acid Composition in a Spanish Commercial Population Fed with Two Different Diets

Stearoyl-CoA desaturase (SCD1 gene) is an enzyme responsible for the endogenous conversion of saturated fatty acid into monounsaturated fatty acids. The objective of this study was to assess the association of a single nucleotide polymorphism (SNP) in the SCD1 gene with the fatty acid composition of beef intramuscular fat of a Spanish commercial bull population (n = 155) finished with two different diets. The results suggested that the marker could be used as a candidate gene to obtain a healthier final product.

Marbling in the longissimus thoracis muscle from lean cattle breeds. Computer image analysis of fresh versus stained meat samples.

One hundred eighty ribeye steaks from Charolais, Limousin and Retinta bulls were used to describe and compare the marbling fat between fresh and stained samples. Image analysis overestimated the intramuscular fat content (P<0.05) in relation to chemical analysis. Staining had a significant effect (P<0.05) on most of the marbling fleck traits, showing an increase in the number of marbling flecks and the proportion of marbling fleck area in the whole and in the ventral half of the longissimus m., and a decrease in the size, length and width of marbling flecks. Breed had a significant influence (P<0.05) on some quantity traits of marbling, but not in the distribution and structure of marbling flecks (P>0.05). Retinta breed was leaner than French breeds and showed fewer and smaller marbling flecks (P<0.05). The results showed a positive correlation (r=0.183 to 0.465) between USDA marbling score, and intramuscular fat by image and chemical analysis.

Guaranteeing Canadian lamb meat quality using near-infrared spectroscopy on intact rack

Abstract: Lamb racks from commercial carcasses were scanned using near-infrared spectroscopy. The prediction accuracies (R 2) for meat quality traits were assessed. Prediction accuracy ranged between 0.40 and 0.94. When predicted values were used to classify meat based on quality, 88.7%–95.2% of samples were correctly classified as quality guaranteed.

Association between functional candidate genes and organoleptic meat traits in intensively-fed beef

The aim of this study was to assess the associations between the single nucleotide polymorphisms in CAPN1, CAST, DGAT1, FABP4, LEP, RORC and SCD1 genes and the sensory meat quality in an intensively fed commercial population (Charolais, Limousin and Retinta breed). This work carried out analyses on a common Spanish population and evaluated the association between the markers and sensory traits. A total of 161 bulls were allocated to two different feedlots with two different finishing diets. Steaks aged for 7 and 21 days were assessed by both untrained and trained sensory panels. A significant association and allelic substitution effect were observed for markers UoG-CAST, LEP: g.73C>T and SCD1: g.878T>C on different descriptors evaluated by a consumer panel (tenderness and overall acceptability). There are no precedents of these kinds of association studies in a Spanish commercial population. The study suggested that CAST, LEP and SCD1 genes have a potential effect on the different measurements of sensory meat quality.