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.

-Characteristics of growth, fat deposition, carcass and meat quality of pigs from the Basque Black Pied breed were described and compared with those of Large White pigs. Four pens, two per breed, of eleven pigs born during the same two week period, were simultaneously fattened and slaughtered, under the same conditions. The experiment was carried out over a fixed duration (124 days) and slaughter was carried out at a fixed average age (202 days). Basque pigs showed lower growth and feed efficiency and higher backfat depth (2.6 vs. 1.7 cm, P < 0.001) than Large White pigs. The difference was especially noticeable in the middle subcutaneous fat layer (0.5 cm, P < 0.001). The meat of Basque pigs was darker, redder, more marbled, and with higher pH values than in Large White pigs. Differences in fatty acid composition were observed between breeds but they were not statistically significant (P > 0.05) because of high variability observed between animals. The Basque breed exhibited an early and higher adipose development and a higher activity of enzymes responsible for lipid synthesis than the Large White. The diameter of intramuscular adipose cells was larger in Basque (40.2 vs. 33.0 µm, P < 0.001) than in Large White pigs. The results show the particular characteristics of the Basque breed as compared to pig lines highly selected for lean growth efficiency.Basque pig / fattening performance / adipose tissue / meat quality Résumé -Comparaison des performances de croissance, du développement des tissus adipeux, de la qualité de la carcasse et de la viande du porc Basque et Large White. Les performances de croissance, le développement des tissus adipeux et la qualité de la carcasse et de la viande de porcs de race Pie Noir du Pays Basque ont été étudiés et comparés à ceux de porcs de race Large White. Pour chaque race, deux lots de onze porcs, nés à la même période, ont été élevés dans les mêmes conditions de logement, d'alimentation, puis abattus au même âge. L'expérience a duré 124 jours et les animaux ont été sacrifiés à un âge moyen constant de 202 jours. Les porcs Basques ont eu une croissance et une efficacité alimentaire plus faibles que les porcs Large White, alors qu'ils ont eu une épaisseur de lard plus élevée (2,6 vs. 1,7 cm, P < 0,001). La différence était particulièrement apparente dans la couche moyenne de lard sous-cutané (0,5 cm, P < 0,001). La viande des porcs * Corresponding author: leo.alfonso@unavarra.es 34 L. Alfonso et al.Basques a été plus foncée, plus rouge, plus marbrée, et avec des valeurs du pH plus élevées que celle des porcs Large White de référence. Des différences dans la composition en acides gras ont été observées entre les races, mais elles n'étaient pas statistiquement significatives (P > 0,05) en raison d'une grande variabilité entre animaux. Les caractéristiques des tissus adipeux ont été significativement différentes, montrant un développement précoce chez les porcs Basques avec des activités élevées des enzymes responsables de la synthèse des lipides. Le diamètre des cell...

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The effects of sex, genotype, and adipose depot on lipogenic enzyme activity have been investigated in Holstein and Pirenaican bulls and heifers, taking into account differences in adipocyte size. Fifteen Pirenaican bulls and 15 heifers and 15 Holstein bulls and 13 heifers were fattened until slaughter (12 to 13 mo old and 450 to 500 kg of body weight). During the fattening period, animals had ad libitum access to commercial concentrates and straw. The 10th rib was dissected to determine the fat content. Adipocyte size and activities of the following lipogenic enzymes were determined: glycerol 3-phosphate dehydrogenase, fatty acid synthase, nicotinamide adenine dinucleotide phosphate (NADP)-malate dehydrogenase, glucose 6-phosphate dehydrogenase, and NADP-isocitrate dehydrogenase, in the omental, perirenal, subcutaneous, and intermuscular adipose depots, respectively. Because adipocyte mean cell volume varied with sex, breed, and depot, regression analyses of log(e) activity per cell and log(e) cell volume were used to compare activities per unit volume. Sex, breed and depot had no effect (P > 0.05) on the gradients of regressions, which did not differ significantly from 1. Thus, activity per unit volume did not vary with cell size. Consequently, sex, breed, and depot effects on the regression analyses were equivalent to effects on activity per unit volume. Females had greater amounts of fat in the 10th rib (P < 0.001), larger adipocytes (P < 0.001) and, in general, greater (P < 0.05) lipogenic activity per cell, even when adjusted for cell size, than males. These findings suggest that differences in adiposity between sexes are mainly due to females having a greater capacity for lipid synthesis, and hence, hypertrophy, than males. When adjusted for differences in carcass weight, Holsteins had larger adipocytes than Pirenaicans. The abdominal depots, omental and perirenal, had a greater adipocyte size (P < 0.001) and, in general, greater lipogenic enzyme activities per cell (P < 0.05) than the subcutaneous and intermuscular carcass depots. However, when activity per cell was adjusted for cell size, subcutaneous depots had greater fatty acid synthae, glucose 6-phosphate dehydrogenase, and NADP-malate dehydrogenase activities than omental and perirenal, indicating that other factors such as nutrient supply may restrict hypertrophy of carcass adipocytes.

Mendizabal, J. A., Delfa, R., Arana, A., Eguinoa, P., González, C., Treacher, T. and Purroy, A. 2003. Estimating fat reserves in Rasa Aragonesa ewes: A comparison of different methods. Can. J. Anim. Sci. 83: 695-701. Four pre-slaughter measurements, liveweight (LW), body condition score (BCS) and fat thickness, measured by ultrasound, in the lumbar (FTL) and sternal regions (FTS), and four post-slaughter measurements, empty liveweight (ELW), hot carcass weight (HCW) and diameter of adipocytes in subcutaneous (DSC) and omental (DOM) fat depots¸ were used to predict the weight of fat in the omental (OM), mesenteric (MES), perirenal (PR), subcutaneous (SC) and intermuscular (IM) depots of ewes. Linear and multiple regressions were fitted to data from 42 adult, non-pregnant and non-lactating Rasa Aragonesa ewes, with liveweights between 29.8 and 79.2 kg and body condition scores between 0.75 and 4.5. Using a single parameter, ELW and HCW gave the most accurate predictions of the total depot fat (R 2 = 0.88 and 0.90, RSD = 1.571 and 1.484 kg, respectively). Multiple regressions predicted total weight of fat depots from the pre-slaughter variables LW, BCS and FTS with an R 2 value of 0.92 (RSD=1.317 kg). This result confirms the utility of using in vivo measures as fat reserve predictors in Rasa Aragonesa ewes.

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The ability to accumulate intramuscular fat (IMF) is a highly variable characteristic in beef cattle. In breeds with a low tendency to accumulate IMF, this can lead to compromised meat quality because of the contribution of fat to such organoleptic attributes as juiciness and taste. This study considered adiposity and gene expression of some of the main markers involved in adipogenesis and lipid metabolism in the subcutaneous (SC) adipose tissue (AT) and the longissimus thoracis muscle (LM) and investigated differences in adipogenic regulation between the tissues during growth and fattening under different conditions. Pirenaica beef cattle were chosen for the study due to the breed's low tendency to accumulate IMF and the breed's regional importance. The young Pirenaica bulls used (n = 16) were allocated to four groups and slaughtered at 6, 12 and 18 months. From 12 months onwards the bulls slaughtered at 18 months were fed diets having different energy densities. Backfat thickness increased from 6 to 12 months (P < 0.05) but then was unchanged, while other fattening parameters such as percentage chemical fat and marbling did not vary. The adipose cell size distribution displayed a bimodal distribution for SC adipocytes and a unimodal distribution for IMF cells, suggestive of tissue-specific hyperplasia. Gene expression of peroxisome proliferator-activated receptor γ (PPARG), CCAAT/enhancer-binding protein α (CEBPA), sterol regulatory element-binding transcription factor 1 (SREBF1), wingless-type MMTV integration site family 10B (WNT10B), fatty acid-binding protein 4 (FABP4), acetyl Co-A carboxylase α, lipoprotein lipase and fatty acid synthase (FASN) were determined by real-time quantitative PCR. Expression did not differ between the experimental groups within the tissues but did differ between the tissues: PPARG, FABP4 and FASN were upregulated in the SC AT, while CEBPA, WNT10B and SREBF1 were upregulated in the LM. Although age and diet energy density did not have a significant effect on increasing the amount of IMF, these factors could have influenced adipocyte development in this tissue differently than in the SC AT. This was evidenced by the different size distributions of the cells in the two tissues, and the differing expression patterns of certain markers in the SC AT and the LM, which may indicate a differential role of PPARG and WNT10B in triggering adipocyte proliferation and fat accumulation capacity.