A. Purroy

Composition and estimation of intramuscular and subcutaneous fatty acid composition in Spanish young bulls

Sixty Pirenaica yearling intact bulls were raised and slaughtered at 519±50kg live weight and 371±18 days of age. Fatty acid composition of intramuscular lipids in longissimus dorsi muscle and subcutaneous fat were determined by capillary gas chromatography. Carcass conformation and fatness, carcass weight, ether extractable intramuscular fat percentage, marbling, dorsal fat thickness, and ultrasonic parameters were recorded to study the relationship between these traits and fatty acid profile. Lipids of subcutaneous adipose tissue had higher monounsaturated fatty acids (MUFA) percentage (49% vs. 33%) but lower saturated fatty acids (SFA) (51% vs. 46%) and polyunsaturated fatty acids (PUFA) (16% vs. 5%) percentages than intramuscular fat depots (p<0.001). Fatter carcasses had higher MUFA percentage and lower PUFA percentage (p<0.01) in intramuscular fat. Carcass weight and conformation would contribute to explain the fatty acid profile of subcutaneous fat (p<0.05). Ultrasound readings reflected the effect of fatness on fat composition.

Distribution Patterns of Infection with Multiple Types of Human Papillomaviruses and Their Association with Risk Factors

Background Infection with multiple types of human papillomavirus (HPV) is one of the main risk factors associated with the development of cervical lesions. In this study, cervical samples collected from 1,810 women with diverse sociocultural backgrounds, who attended to their cervical screening program in different geographical regions of Colombia, were examined for the presence of cervical lesions and HPV by Papanicolau testing and DNA PCR detection, respectively. Principal Findings The negative binomial distribution model used in this study showed differences between the observed and expected values within some risk factor categories analyzed. Particularly in the case of single infection and coinfection with more than 4 HPV types, observed frequencies were smaller than expected, while the number of women infected with 2 to 4 viral types were higher than expected. Data analysis according to a negative binomial regression showed an increase in the risk of acquiring more HPV types in women who were of indigenous ethnicity (+37.8%), while this risk decreased in women who had given birth more than 4 times (−31.1%), or were of mestizo (−24.6%) or black (−40.9%) ethnicity. Conclusions According to a theoretical probability distribution, the observed number of women having either a single infection or more than 4 viral types was smaller than expected, while for those infected with 2–4 HPV types it was larger than expected. Taking into account that this study showed a higher HPV coinfection rate in the indigenous ethnicity, the role of underlying factors should be assessed in detail in future studies.

Multivariate study of different beef quality traits from local Spanish cattle breeds

Different raw beef quality traits from four local Spanish cattle breeds were studied using correlation, factorial, discriminant and multiple regression analysis. The following variables were studied after 0, 5, 10 and 15 days of storage under 60% O2, 30% CO2 and 10% N2 modified atmosphere packaging (MAP): colour physical variables, meat pigments, sensory degradation of odour and colour, microbial counts, thiobarbituric acid (TBA), pH, drip loss, lipid composition and volatile compounds. The degradation of raw beef quality was related to the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-methyl-2-heptene, 2-octene, 3-octene, 2-propanone, Enterobacteriaceae and aerobial plate counts (APC), metmyoglobin (MMb), lightness (L*), yellowness (b*), drip loss and TBA. Among these variables, TBA, b* and MMb may be useful in evaluating raw beef quality. No variables related to fat, except for TBA, including pH were limiting factors of the colour and odour shelf-life of raw beef under MAP. Each breed had some characteristics that were unique and these differences may influence the stability of meat to oxidation depending on myoglobin concentration and the polyunsaturated fatty acid (PUFA)/saturated fatty acid (SFA) ratio.

Effect of whole linseed and rumen-protected conjugated linoleic acid enriched diets on feedlot performance, carcass characteristics, and adipose tissue development in young Holstein bulls

Forty-eight young Holstein bulls (slaughtered at 458.6±9.79 kg body weight) were used to evaluate the effect of whole linseed and conjugated linoleic acid (CLA) supplementation on animal performance, adipose tissue development, and carcass characteristics. The animals were fed with one of four isoenergetic and isoproteic diets: control (0% linseed, 0% CLA), linseed (10% linseed, 0% CLA), CLA (0% linseed, 2% CLA), and linseed plus CLA (10% linseed, 2% CLA). Animal performance and carcass characteristics were unaffected by diet composition. Adding linseed or CLA to the concentrate diet did not result in significant differences in adipocyte size and number or lipogenic enzyme activity. However, while the frequency distribution of subcutaneous adipocyte diameters followed a normal distribution, the frequency distribution of intramuscular adipocyte diameters was not normal in any dietary group (skewness coefficients: 0.8, 1.2, 0.9, 0.8 for control, linseed, CLA, and linseed plus CLA, respectively; P<0.05), indicative of adipocyte proliferation in the intramuscular adipose tissue.

Predicting meat yields and commercial meat cuts from carcasses of young bulls of Spanish breeds by the SEUROP method and an image analysis system.

The SEUROP system is currently in use for carcass classification in Europe. Image analysis and other new technologies are being developed to enhance and supplement this classification system. After slaughtering, 91 carcasses of local Spanish beef breeds were weighed and classified according to the SEUROP system. Two digital photographs (a side and a dorsal view) were taken of the left carcass sides, and a total of 33 morphometric measurements (lengths, perimeters, areas) were made. Commercial butchering of these carcasses took place 24 h postmortem, and the different cuts were grouped according to four commercial meat cut quality categories: extra, first, second, and third. Multiple regression analysis of carcass weight and the SEUROP conformation score (x variables) on meat yield and the four commercial cut quality category yields (y variables) was performed as a measure of the accuracy of the SEUROP system. Stepwise regression analysis of carcass weight and the 33 morphometric image analysis measurements (x variables) and meat yield and yields of the four commercial cut quality categories (y variables) was carried out. Higher accuracy was achieved using image analysis than using only the current SEUROP conformation score. The regression coefficient values were between R(2)=0.66 and R(2)=0.93 (P<0.001) for the SEUROP system and between R(2)=0.81 and R(2)=0.94 (P<0.001) for the image analysis method. These results suggest that the image analysis method should be helpful as a means of supplementing and enhancing the SEUROP system for grading beef carcasses.

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 .

Breed effects on cellularity and lipogenic enzymes in growing Spanish lambs

Abstract Size and number of adipocytes and lipogenic enzyme activity in different adipose depots in Lacha (L) and Rasa Aragonesa (RA) lambs has been compared. 42 L males were assigned into three different groups and were slaughtered at the following live weights (LW): 11.4 kg (L12), 24.6 kg (L24) and 35.3 kg (L36). Forty-five RA males were also assigned into three groups and were slaughtered at similar LW than L lambs: 11.70 kg (RA12), 24.5 kg (RA24) and 35.8 kg (RA36). L12 and RA12 lambs were fed on ewe milk until they were slaughtered. After weaning, L24, L36, RA24 and RA36 lambs were fed on commercial concentrate and barley straw, both ad libitum, until they were slaughtered. The parameters studied in omental (OM), mesenteric (MES) and perirenal (PR) adipose depots were: the weight of adipose tissue, the number and size of adipocytes and the activity of Glycerol 3-phosphate dehydrogenase (G3PDH), Fatty acid synthetase (FAS), NADP–malate dehydrogenase (MD) and Glucose 6-phosphate dehydrogenase (G6PDH); in subcutaneous (SC) and intermuscular (IM) depots the same parameters were determined except the adipocyte number. Internal adipose tissue weight in RA lambs was higher than in L lambs due to a greater number of adipocytes at 12 kg LW and to larger adipocytes size at 24 and 36 kg LW. Besides the greater adiposity in RA lambs was consistent with a higher G3PDH enzyme activity, which is tightly correlated with triacylglycerol esterification. Nevertheless, FAS activity was higher in L lambs. In conclusion, it is noted that the different intensity of hypertrophy–hyperplasia and enzyme activities observed in the lambs was the cause for the different adiposity that has been found.

Changes in adipose tissue accumulation in Rasa Aragonesa breed lambs during growth and fattening

Changes during growth and fattening in the number and size of adipocytes and in the activity of the lipogenic enzymes glycerol 3-phosphate dehydrogenase (G3PDH), fatty acid synthetase (FAS) and lipoprotein lipase (LPL) were studied in perirenal (PR) and subcutaneous (SO adipose depots of 28 male lambs of Rasa Aragonesa Spanish breed. Three groups of animals were slaughtered at: 32 (s.d. 6) (no. = 10), 89 (s.d. 8) (no. = 10) and 120 (s.d. 8) (no. = 8) days of age. A significant increase in the quantity of fat was observed as the age of the lambs increased ( P P P P

Effects of Addition of Linseed and Marine Algae to the Diet on Adipose Tissue Development, Fatty Acid Profile, Lipogenic Gene Expression, and Meat Quality in Lambs

This study examined the effect of linseed and algae on growth and carcass parameters, adipocyte cellularity, fatty acid profile and meat quality and gene expression in subcutaneous and intramuscular adipose tissues (AT) in lambs. After weaning, 33 lambs were fed three diets up to 26.7 ± 0.3 kg: Control diet (barley and soybean); L diet (barley, soybean and 10% linseed) and L-A diet (barley, soybean, 5% linseed and 3.89% algae). Lambs fed L-A diet showed lower average daily gain and greater slaughter age compared to Control and L (P < 0.001). Carcass traits were not affected by L and L-A diets, but a trend towards greater adipocyte diameter was observed in L and L-A in the subcutaneous AT (P = 0.057). Adding either linseed or linseed and algae increased α-linolenic acid and eicosapentaenoic acid contents in both AT (P < 0.001); however, docosahexaenoic acid was increased by L-A (P < 0.001). The n-6/n-3 ratio decreased in L and L-A (P < 0.001). Algae had adverse effects on meat quality, with greater lipid oxidation and reduced ratings for odor and flavor. The expression of lipogenic genes was downregulated in the subcutaneous AT (P < 0.05): acetyl-CoA carboxylase 1 (ACACA) in L and L-A and lipoprotein lipase (LPL) and stearoyl-CoA desaturase (SCD) in L-A. Fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2) and fatty acid elongase 5 (ELOVL5) were unaffected. In the subcutaneous AT, supplementing either L or L-A increased peroxisome proliferator-activated receptor gamma (PPARG) and CAAT-enhancer binding protein alpha (CEBPA) (P < 0.05), although it had no effect on sterol regulatory element-binding factor 1 (SREBF1). In the intramuscular AT, expression of ACACA, SCD, FADS1 and FADS2 decreased in L and L-A (P < 0.001) and LPL in L (P < 0.01), but PPARG, CEBPA and SREBF1 were unaffected.

The effect of vitamin A supplementation on postnatal adipose tissue development of lambs.

Vitamin A (retinoic acid) is known to be an adipogenic factor influencing both in vitro and in vivo cell development. This study aimed to determine its effect on lamb adipose tissue development during the early phase of postnatal development until 100 d of age. Male lambs (n = 24) of the Rasa Aragonesa breed were used. At birth, lambs were assigned to 1 of 2 experimental groups: 1) the control (C) group, which received feed without vitamin A supplementation, and 2) the vitamin A (V) group, which received a supplement of 500,000 IU/animal twice per week from birth to slaughter. The effect of vitamin A supplementation was studied at 16.8 +/- 0.35 kg of BW (58 +/- 0.7 d of age) and at 27.8 +/- 0.78 kg of BW (101 +/- 6.5 d of age). The variables of lamb growth, carcass, LM area, and lipid content were analyzed. To study adipose tissue development, the amount of adipose tissue accumulated, the size and number of adipocytes, and lipogenic enzyme activities (glycerol 3-phosphate dehydrogenase, fatty acid synthase, and glucose 6-phosphate dehydrogenase) of the omental, perirenal, and s.c. depots were quantified. Results showed that vitamin A supplementation had no influence on growth, carcass variables, LM area, and lipid content during lamb growth but that the number of adipocytes in the perirenal depot was 30% greater in lambs of the V group (P < 0.05) and that these lambs had smaller adipocytes in the omental and perirenal depots (P = 0.06) at 28 kg of BW (101 d of age). These results suggest that the intake of this level of vitamin A during the whole period of growth of the lambs influenced the processes of hyperplasia and hypertrophy in the different adipose depots, depending on their degree of maturity.