Adipose Tissue Of Lambs Research Articles

Ethylcellulose oleogels of oil glycerolysis products as functional adipose tissue mimetics

Replicating the functionality of animal fat with its plant/microbial counterparts plays a key role in successful design of plant-based analogues of animal-derived foods. Given the intricate structure of animal adipose tissue, merely substituting animal fats in plant foods with saturated bulk fats and oils often results in compromised mechanical and sensory attributes. Animal adipose tissue is comprised of adipocytes encapsulated by connective tissue. Simply replacing this tissue with coconut oil will not succeed in creating a true meat mimetic. Enzymatically glycerolized oils are derived from the conversion of native triacylglycerols in oils into partial glycerides. They are a promising fat alternative that could diminish the need for tropical and hydrogenated oils in plant-based meat products. Oils can be converted into fats using a mild enzymatic reaction without the use of hydrogenation or addition of saturated hardstocks. In this study, we explored the potential of oleogels made from glycerolysis products to mimic adipose tissue. Utilizing various enzymatically structured oils, we formulated oleogels with ethylcellulose (EC) of differing molecular weights (EC20 and EC45) at a 5% concentration. The thermal, microstructural, and mechanical properties of the oleogels were compared to those of whole pork, beef, and lamb adipose tissue. In general, the thermal and structural characteristics of both EC45 and EC20 oleogels closely matched those of the glycerolysis products they originated from. Mechanical properties largely depended on the solid fat content, with oleogel systems richer in saturated fatty acids exhibiting more ordered and rigid structure, akin to adipose tissue. Additionally, pronounced resemblance was observed in thermal softening behavior of some of oleogel systems and that of animal adipose tissue. Our findings highlight the potential of EC oleogels from glycerolysis products in creating meat substitutes, thus preventing the characteristic oil-loss from plant-based meat alternatives when cooked, which lead to dry and grainy sensory textures.

Influence of Dietary Protein Source and Level on Histological Properties of Muscle and Adipose Tissue of Lambs.

The muscle and adipose tissue histological properties in wether and ewe lambs of Gentile di Puglia breed, fed diets including two protein sources [soybean meal (SB) and SB plus distillers dried grain with solubles (DD)] and three protein levels (12.5, 15.7, and 18.9%) were evaluated. Muscle samples were collected from the longissimus/rump, cut, and stained (reciprocal aerobic and anaerobic stains) for muscle fiber typing and fat cell characterization. Fibers were classified as α-red, β-red, and α-white. Lambs fed SB had larger α-white (p < 0.10) and smaller-diameter β-red and α-red fibers (p < 0.05). Among dietary protein levels, lambs fed 12.5% protein exhibited the highest percentage of α-red and the greatest diameter of α-white fibers, whereas wethers had a higher percentage of α-red (p < 0.05), and ewes had a higher percentage of α-white fibers (p < 0.05). Intramuscular fat cells were larger (p < 0.10) in ewes than in wethers. Lambs in the group fed 12.5% protein had larger subcutaneous fat cells at the sacral vertebrae location. Overall, both sources and levels of dietary protein had significant effects on lamb muscle and fat histological features, suggesting the potential of modulating muscle or fiber types through dietary protein strategies.

Monensin supplementation downregulated the expression signature of genes involved in cholesterol synthesis in the ruminal epithelium and adipose tissue of lambs

To understand the metabolic mechanisms regulating lipid metabolism by monensin, Afshari male lambs (n = 16) with 41.0 ± 2.4kg body weight (BW, mean ± SD) at approximately 180days of age were randomly assigned equally to two dietary treatments. After a 21-day pre-adaptation period, all animals in two groups continued to receive the basal diet, but one group received no monensin supplementation (control) while the other group received 30mg/day of monensin per animal. Individual BW was recorded weekly to determine the average daily body weight gain (ADG). At the end of the 56-day experimental period, lambs were weighed and slaughtered. Monensin supplementation did not affect BW, ADG, and rumen fermentation characteristics. However, monensin significantly downregulated the sterol regulatory element-binding protein (SREBP)-2 gene expression in all sample tissues (p < 0.05). Also, monensin downregulated expressions of SREBP-1c and peroxisome proliferator-activated receptor (PPAR)-γ in back fat tissues. Monensin increased the expression of 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS)-2, but it decreased the mRNA abundance of HMGCS-1 in the rumen epithelial tissues (p < 0.05). Our data suggest that monensin downregulates cholesterol synthesis via inhibition of HMGCS-1 and impairment of the SREBP pathway, probably due to a crosstalk among different tissues to control energy metabolism.

Effects of silage to concentrate ratio and duration of feeding on the fatty acid composition of ovine muscle and adipose tissue

Context Dietary strategies may influence the fatty acid composition of sheep meat and ultimately its nutritional and sensory quality. Aim This study investigated the effects of silage to concentrate ratio and feeding duration on the concentration of intramuscular fatty acids and branched chain fatty acid in subcutaneous adipose tissue of lambs. Methods Pasture fed lambs were assigned in groups of 11 to one of nine dietary treatments consisting of silage to cereal concentrate at ratios (dry matter basis) of 100:0 (silage), 50:50 (silage:concentrate) or 0:100 (concentrate) for three feeding durations (36, 54 or 72 days) pre-slaughter. A 10th group of 11 lambs remained at pasture until slaughter. Fatty acid methyl esters were prepared using a microwave-assisted method and quantified by gas chromatography with flame ionisation detection. Results The concentration of n-3 polyunsaturated fatty acids (PUFA) and proportions of C18:3n-3 and C18:2 cis-9 trans-11 decreased for mixed feed and/or concentrate treatments, but not for silage, from 36 to 72 days. The C18:2n-6 and n-6 PUFA concentrations increased for mixed feed and concentrate, but not for silage, from 36 to 72 days. The animals that remained at pasture had lower C18:2n-6 and n-6 PUFA than those receiving mixed feed for 72 days, concentrate for 54 days and concentrate for 72 days, but higher C18:3n-3, C18:2 cis-9 trans-11 and n-3 PUFA concentrations than the indoor finishing groups. The n-6/n-3 PUFA ratio was lower in pastured lambs compared to the other groups. 4-Methyloctanoic acid and 4-ethyloctanoic acid were higher in concentrate and mixed feed treatments than in silage while 4-methylnonanoic acid increased with increase in concentrate level in the diet. Conclusion The ratio of silage to concentrate in the diet and duration of feeding pre-slaughter influence the fatty acid composition of muscle and subcutaneous adipose tissue of lambs. Implications The results are important for lamb producers in understanding the nutritional and sensory implications of altering lamb diets.

Dietary Sea Buckthorn Pomace Induces Beige Adipocyte Formation in Inguinal White Adipose Tissue in Lambs.

Simple SummaryHeat production is important for the survival of young animals, especially for those born in a cold winter. During this process, both brown and beige adipose tissues play an important role. Sea buckthorn is a natural source of bioactive compounds and has multiple health benefits. The aim of this study was to determine whether dietary sea buckthorn pomace supplementation could affect beige cell formation in lambs. Here, we found that dietary sea buckthorn pomace could promote beige adipocyte formation, increase mitochondrial numbers, and improve insulin sensitivity in inguinal white adipose tissue. These results will be useful for increasing heat production through modulation of beige cell formation in young lambs.The sea buckthorn contains substantial amounts of bioactive compounds. The objective of this study was to investigate the effects of dietary sea buckthorn pomace (SBP) on sheep beige adipocyte formation. A total of thirty lambs were equally divided into three groups and fed with diets containing different levels of SBP: 0% SBP (Control), 7.8% SBP (7.8SBP), and 16.0% SBP (16SBP). The results showed that dietary SBP affected inguinal adipocytes’ size distribution, and increased both UCP1 protein content (p < 0.05) and mitochondrial numbers (p < 0.05). mRNA expression of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1, and mitochondrial transcription factor A were increased when animals were subjected to 16% SBP (p < 0.05). Supplementation with 16% SBP increased CCAAT/enhancer-binding protein β content (p < 0.05) and PR domain containing 16 mRNA abundance (p < 0.05). Consistently, inguinal white adipose tissue (iWAT) from the 16SBP group exhibited increased insulin sensitivity, which was associated with elevated glucose transporter 4 abundance (p < 0.05). Importantly, AMP-activated protein kinase (AMPK) was activated in the 16SBP group (p < 0.05). Collectively, these results suggest that dietary SBP promotes iWAT browning in lambs, which might be through the activation of the AMPK–PGC-1α–UCP1 signaling pathway.

Research Regarding Fatty Acid Profile and Health Lipid Indices in the Lambs Meat of Employing Feed Supplemented with Different Vegetable Oils

Enhancing healthy fatty acids (FA) in lamb tissues is a important research issue in meat science. The present study examined the effects of feeding-protected lipid supplements rich in linoleic acid or linolenic acid on the lipid composition of muscle and adipose tissues of lambs. Thirty, 10-week-old Tsigai breed ram lambs were assigned to one of three experimental diets (forage/concentrate ratio 40:60): no oil Ca soap (C-Control), with 4% sunflower oil Ca soap (SO-high in 18:2n-6), with 4% camelina oil Ca soap (CO-high in 18:3n-3). The diet high in a-linolenic acid (CO diet) produced the highest levels of n-3 FAs: 18:3n-3 (ALA), 20:5n-3 (EPA) and 22:6n-3 (DHA) intramuscular fat. In addition, the animals fed with the diet CO have intramuscular fat the lowest n-6/n-3 ratio, atherogenic (AI) and thrombogenic index (TI). In the intramuscular fat of the animals fed with the diet high in linoleic acid (SO diet), conjugated linoleic acid (CLA) isomers and trans 18:1 reached their highest concentrations. The results of this study indicated that linoleic acid was more effective in enhancing contents of CLA in muscle and adipose tissue than linolenic acid, which contributes to the enrichment of n-3 FA lamb meat. Feeding camelina oil Ca soap has been shown to be the most effective dietary management to improve health lipid indices (n-6/n-3 ratio, AI, TI) in lambs� meat.

Effect of Protected Fat as Ca-Soap and Formaldehyde-Treated Full-Fat Soybean in the Finisher Diet of Lambs on Growth Performance, Carcass Traits and Fatty Acid Profile

Effect of feeding Ca-soap and formaldehyde-treated full-fat soybean (FFS) on growth, carcass traits and fatty acid profile of thirty male finisher (3 months) lambs of native Malpura breed was evaluated. Lambs were equally divided into two groups and fed on two isocaloric and isonitrogenous diets, one with Ca-soap 6 percent (T1) and the other with equivalent fat added through FFS (T2). Lambs were slaughtered at 6 months of age. Carcass traits and proximate composition were comparable in both the dietary groups. There were increased C16:0 and C18:1n9t fatty acids in Ca-soap-incorporated diet, whereas C15:1, C18:2n6c and C18:3n3 fatty acids were higher in FFS-supplemented diet. The fatty acid profile of Longissimus dorsi (LD) muscle revealed higher (P < 0.05) content of C14:0, C16:0, C18:2n6c fatty acids in FFS, whereas C18:3n3 fatty acid was higher (P < 0.05) in Ca-soap-supplemented diet. Saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA) and ω-3 fatty acids were higher (P < 0.05) in Ca-soap, while monounsaturated fatty acids were higher (P < 0.05) in FFS-supplemented diet. This leads to higher PUFA: SFA ratio in Ca-soap-supplemented diet as compared to FFS. Adipose tissues of lambs fed Ca-soap showed higher (P < 0.05) contents of C18:2n6c and C18:3n3, whereas lambs fed FFS had higher C14:0, C16:0, C18:1n9t and C18:1n9c fatty acids. Thus, feeding of Ca-soap compared to FFS-supplemented diet could preferentially modulate PUFA, ω6 and ω3 fatty acid in LD muscle fat as well as adipose tissue for the benefit of human consumption.

Effect of various protein sources in feed on the fatty acid composition of adipose depots in lambs

The effect of inclusion of different protein sources-sunflower meal, rapeseed meal and dry distillers’ grain with solubles (DDGS) on the fatty acid profile of subcutaneous, intermuscular, omental and perirenal fat was studied in male lambs of Bulgarian Dairy Synthetic Population. The presence of sunflower meal in the diet of the lambs led to highest content (P<0.05) of C16:0 in the omental fat while C18:0 displayed lowest content in the perirenal fat of the lambs fed DDGS (P<0.05). The content of C16:1 in the intermuscular adipose tissue was significantly (P<0.05) affected by the dietary treatment. It was highest in the rapeseed meal fed lambs and lowest in the lambs that consumed DDGS. Significant influence of the diet on C18:1 was observed in subcutaneous and omental fat (P<0.05) as its content was highest in the group fed rapeseed meal and lowest in the DDGS group. The lambs fed DDGS containing diet showed significantly increased content of C18:2 and the total amount of polyunsaturated fatty acids in the subcutaneous (P<0.05), intermuscular and omental fat (P<0.01) as well as in the perirenal fat (P<0.001) and decresead content of the total saturated fatty acids in the omental and perirenal adipose tissue (P<0.05). Rapeseed meal led to substantially higher content of C18:3n-3 in the four depots when compared to the other two protein sources. These results could suggest that the inclusion of rapeseed meal and DDGS in the diet could be used to positively manipulate the lipid profile in lamb adipose tissues.

Effect of pasture and concentrate diets on concentrations of carotenoids, vitamin A and vitamin E in plasma and adipose tissue of lambs

The effect of different diets on the content of carotenoids, fat-soluble vitamins (retinol and tocopherol) and color measurements in sheep tissues was assessed, to study the possible links with the livestock production system for both nutrition and traceability. Three groups of animals were considered: 15 lambs fed on pasture (G1), 15 lambs fed on concentrate (G2) and 15 suckling lambs (G3) whose mothers were grass-fed. Lutein and β-carotene appeared only in plasma from grazing lambs, so they appear useful to differentiate lambs fed on pasture. Furthermore, retinol and α-tocopherol content in fat were significantly higher (p<0.01) in the animals fed on an extensive system (1.48±0.08 and 42.4±1.76μg/g fat, respectively) than those fed on an intensive one (1.03±0.08 and 34.8±0.23μg/g fat, respectively). When fat-soluble vitamin (retinol and tocopherol) levels and the absolute value of the integral from the reflectance spectrum, between 450 and 510nm, from fat samples were used in a discriminant model, 100% of the lambs were correctly classified according to their feeding system (pasture vs. concentrate).

Increasing concentrations of wheat dry distillers’ grains with solubles in iso-nitrogenous finishing diets reduce lamb performance

It was hypothesized that the inclusion of wheat dry distillers’ grains with solubles (WDDGS) up to 470g/kg dry matter (DM), fed to lambs in iso-nitrogenous diets, would neither affect growth performance, nor subcutaneous adipose tissue fatty acid composition. Thus, this study aimed to assess the effects of increasing concentrations of WDDGS in iso-nitrogenous diets on in vitro fermentation, in sacco degradation, growth performance and fatty acid profiles of adipose tissue in lambs. Increasing concentrations of WDDGS (100, 300 and 470g/kg dry matter (DM)) were achieved by replacing soybean meal, alfalfa hay and soybean hulls. In vitro fermentation of the diets was conducted to measure fermentation variables and CH4 production. In situ digestion kinetics of DM, crude protein (CP), and neutral detergent fiber (NDF) of the treatment diets were evaluated using three ruminally cannulated cows. Additionally, 60 lambs were used to determine the effect of WDDGS on growth performance and fatty acid profiles of subcutaneous tail fat. In the in sacco study, WDDGS increased (P=0.03) DM, CP and NDF effective degradability and reduced (P<0.01) rumen undegradable protein. In the in vitro incubations, CH4 production (mg/gDMD) increased (P=0.05) in the 470g/kg WDDGS group. In the growth trial, increasing WDDGS in the diet linearly reduced DMI (P=0.02), ADG (P<0.01) and hot carcass weight (P<0.01). Linear increases in trans-10 octadecenoic acid (P=0.02) and linear decrease in oleic acid (P<0.01) resulted in a linear reduction of total monounsaturated fatty acids (MUFA; P=0.02) yet, linoleic acid was linearly increased (P<0.01). In summary, increasing concentrations of WDDGS in iso-nitrogenous diets fed to lambs decreased animal performance and negatively affected the fatty acid profile of adipose tissue.

Effects of replacing barley grain with wheat dry distillers' grains on growth performance, eating behavior, and subcutaneous fatty acid profiles of lambs

The aim of the study was to assess the effects of replacing barley grain with increasing concentrations of wheat dry distillers' grains with solubles (WDDGS) on the growth performance and fatty acid profile of adipose tissue in lambs. Increasing concentration of WDDGS was achieved by replacing barley grain with WDDGS. Thirty-nine weaned crossbred lambs were completely randomized by weight and assigned to three dietary treatments (control, 200 g/kg WDDGS, and 400 g/kg WDDGS). Increasing WDDGS in the diet affected eating rate, total daily intake, and average daily gain. Total saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in subcutaneous fat were unaltered, but proportions of linolenic acid were increased. This study suggests that a concentrated diet containing 400 g/kg WDDGS fed to lambs as replacement of barley grain, improved lamb intake and growth performance as compared to a barley-based diet.

The fatty acid profile of muscle and adipose tissue of lambs fed camelina or linseed as oil or seeds

The objective of this study was to evaluate the impact of diets enriched with plant oils or seeds, high in polyunsaturated fatty acids (PUFA), on the fatty acid profile of sheep intramuscular and subcutaneous adipose tissue (SAT). Sixty-six lambs were blocked according to initial body weight and randomly assigned to six concentrate-based rations containing 60 g fat/kg dry matter from different sources: (1) Megalac (MG; ruminally protected saturated fat), (2) camelina oil (CO), (3) linseed oil (LO), (4) NaOH-treated camelina seed (CS), (5) NaOH-treated linseed (LS) or (6) CO protected from ruminal saturation by reaction with ethanolamine; camelina oil amides (CA). The animals were offered the experimental diets for 100 days, after which samples of m. longissimusdorsi and SAT were collected and the fatty acid profile determined by GLC. The data were analyzed using ANOVA with ‘a priori’ contrasts including camelina v. linseed, oil v. NaOH-treated seeds and CS v. CA. Average daily gain and total fatty acids in intramuscular adipose tissue were similar across treatments. The NaOH-treatment of seeds was more effective in enhancing cis-9, trans-11 conjugated linoleic acid (CLA) incorporation than the corresponding oil, but the latter resulted in a higher content of trans-11 18:1 in both muscle neutral and polar lipids (P < 0.01, P < 0.001, respectively). Inclusion of LS resulted in the highest PUFA:saturated fatty acid (SFA) ratio in total intramuscular fat (0.22). The NaOH-treatment of seeds resulted in a higher PUFA/SFA ratio (0.21 v. 0.18, P < 0.001) than oils and on average, linseed resulted in a higher PUFA/SFA ratio than camelina (P < 0.01). Lambs offered LS had the highest concentration of n-3 PUFA in the muscle, while those offered MG had the lowest (P < 0.001). This was reflected in the lowest (P < 0.001) n-6: n-3 PUFA ratio for LS-fed lambs (1.15) than any other treatment, which ranged from 2.14 to 1.72, and the control (5.28). The trends found in intramuscular fat were confirmed by the data for SAT. This study demonstrated the potential advantage from a human nutrition perspective of feeding NaOH-treated seeds rich in PUFA when compared to the corresponding oil. The use of camelina amides achieved a greater degree of protection of dietary PUFA, but decreased the incorporation of biohydrogenation intermediates such as cis-9, trans-11 CLA and trans-11 18:1 compared to NaOH-treated seeds.

Persistence of pasture feeding volatile biomarkers in lamb fats

Abstract Recent studies have evidenced volatile biomarkers in ruminant tissues that distinguish between exclusive pasture and exclusive concentrate diets. As ruminants usually alternate these diets, we set out to monitor the persistence of volatile tracers of pasture diet in perirenal fat and caudal subcutaneous fat in lambs ( n = 28) fed on pasture and then fattened at increasing levels with concentrate: Four groups of lambs ( n = 7) were stall-finished to achieve a final weight gain of 0, 4, 8, and 12 kg, respectively. Thirty nine pasture diet tracers including terpenes, 2,3-octanedione and toluene were found that distinguish between the four different diets in both tissues. According to their clearance rates monitored in the adipose tissues of lambs fattened with different amounts of concentrate, different types of persistence were evidenced. Most of the compounds exhibited a “short” persistence, e.g. 2,3-octanedione and terpenes, while some displayed a “medium” or “long” persistence. Finally, performing discriminant analysis on ratios of tracers from the two adipose tissues enabled the correct differentiation of the four different diets.

Meat odour and flavour and indoles concentration in ruminal fluid and adipose tissue of lambs fed green herbage or concentrates with or without tannins

A 2 × 2 factorial experiment was carried out to evaluate the effect of herbage or concentrate feeding system and tannin addition to diet on skatole and indole in ruminal fluid and adipose tissue and meat sensory properties. Twenty-eight male lambs aged 45 days were randomly assigned to one of two feeding systems (vetch green herbage or concentrates, n = 14) and within feeding system to one supplement (quebracho tannins added to the diet or none). Animals were kept in singular pens and slaughtered at the age of 105 days. Indole (P < 0.05) and skatole (P < 0.01) concentrations in ruminal fluid were higher in lambs fed herbage compared to those given concentrates. Skatole in ruminal fluid tended to be present at lower concentrations in animals that received the tannin supplementation (P = 0.07). Indole was also higher in the caudal fat of animals fed green vetch compared to those fed concentrate (P = 0.04). Skatole concentration was lower in the fat of lambs fed concentrates compared to those given herbage (P = 0.05) and was lower in the fat of animals supplemented with tannins compared to the animals not supplemented (P = 0.01). Sheep meat odour was lower in meat from animals supplemented with tannins compared to those not supplemented (P < 0.01). It is concluded that tannins are more effective in reducing skatole formation in ruminants when they are associated with concentrate diets than green herbages.

Authentication of Meat Products: Determination of Animal Feeding by Parallel GC-MS Analysis of Three Adipose Tissues

Authentication of farm animal rearing conditions, especially the type of feeding, is a key issue in certification of meat quality and meat products. The purpose of this article was to analyze in parallel the volatile fraction of three adipose tissues excised from 16 lambs in order to authenticate two animal diets: pasture (n = 8) and concentrate (n = 8). On the basis of growth rate and anatomical location, three different lamb adipose tissues were analyzed: perirenal fat (PRF), caudal subcutaneous fat (CSCF), and heart fat (HF). An initial experiment was used to optimize the extraction of volatile compounds from the adipose tissues. Using a lipid liquid phase extraction, heating the ground tissue to 70 degrees C, was shown to be the best sample preparation mode before dynamic headspace-gas chromatography-mass spectrometry (DH-GC-MS) analysis to achieve a good representation of the starting material, while getting a good extraction and reproducibility. Next, the application of an instrumental drifts correction procedure to DH-GC-MS data enabled the identification of 130 volatile compounds that discriminate the two diets in one or several of the three tissues: 104 were found in PRF, 75 in CSCF, and 70 in HF. Forty-eight of these diet tracers, including 2,3-octanedione, toluene, terpenes, alkanes, alkenes, and ketones, had previously been identified as ruminant pasture-diet tracers and can be considered generic of this type of animal feeding. Moreover, 49 of the 130 compounds could identify diets in only one tissue, suggesting that complementary analysis of several tissues is superior for diet identification. Finally, multivariate discriminant analyses confirmed that the discrimination was improved when PRF, CSCF, and HF were considered simultaneously, even if HF contributed minimal information.

The effect of vitamin A supplementation on postnatal adipose tissue development of lambs1

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.

Effect of level of linseed on fatty acid composition of muscles and adipose tissues of lambs with emphasis on trans fatty acids

The effects of linseed content in concentrates on the fatty acid (FA) composition of adipose tissues and muscles of lambs were studied in a 2 × 4 design: males (M) vs. females (F) and linseed content (0%, L0, 3%, L3, 6%, L6, 9%, L9). FA proportions were determined both on a DB-wax and on a CP-Sil column in perirenal (PR), dorsal subcutaneous (SC) adipose tissue and in longissusmus dorsi muscle (IM). No effects of linseed contents in the diet on growth performances either in male or female lambs were observed. Linseed supplementation tended to decrease the fatness score. The proportion of linolenic acid increased linearly with the linseed content in the diet, from: 0.6, 0.5, and 0.5% for L0 to 1.9, 1.6, and 1.3% for L9, in PR, SC and IM, respectively. The increase in n − 3 PUFA and in total PUFA was similar to that of linolenic acid. The n − 6: n − 3 ratio decreased from 5.7, 5.3 and 5.8 for L0 to 1.8, 1.7 and 2.7 for L9, in PR, SC and IM, respectively. There was no change in the proportion of docosahexaenoic acid with linseed supplementation. The proportions of C18:1 trans-10 and C18:1 trans-11 did not vary in PR, SC and IM with linseed supplementation. The total proportion of trans-octadecenoic acid was high in each tissue type and group of lambs. C18:1 trans-10 represented about half of the total trans-octadecenoic isomers. With an increase in linolenic acid, most cis- and trans-octadecenoic isomers also increased, but trans-10 and trans-11 isomers did not and cis-9 and cis-11 isomers decreased. With linseed supplementation there was a decrease in the Δ9 desaturase indices in SC.

Effects of diet and vitamin E supplementation on the distribution of vitamin E in plasma, muscle, liver and adipose tissue in lambs fed on concentrates alone or with grass silage

Vitamin E protects the animal from oxidative stressin vivoand when it is administered at supranutritional levels it enhances the oxidative stability of meat. Studies have shown that poor absorption of vitamin E often occurs when concentrates are fed to lambs. Distribution of vitamin E in plasma, skeletal muscle, liver (short-term and fast release depot) and adipose tissue (long-term and slow release depot) provides useful information about the overall vitamin E status of the animals. This work studied the distribution of vitamin E in the tissues after supplementation in relation to diet and to the dietary level.

Feeding lambs high-oleate or high-linoleate safflower seeds differentially influences carcass fatty acid composition.

Our objective was to determine effects of dietary high-oleate (Oleate; 76% 18:1) or high-linoleate (Linoleate; 78% 18:2) safflower seeds on fatty acids in muscle and adipose tissue of feedlot lambs. White-faced ewe lambs (n = 36) were fed a beet pulp, oat hay, and soybean meal basal diet (Control), blocked by BW, and allotted randomly to dietary treatments. Cracked safflower seeds were used in isocaloric and isonitrogenous replacement of beet pulp, oat hay, and soybean meal so that Oleate and Linoleate diets contained 5.0% additional fat. Fatty acids were determined in semitendinosus, longissimus dorsi (longissimus), and adipose tissue from the tail head (tailhead adipose tissue), adjacent to the 12th rib (s.c. adipose tissue), and kidney and pelvic fat (KPH adipose tissue) depots. Fatty acid data were analyzed within muscle and adipose tissue as a split-block design. Single degree of freedom orthogonal contrasts were used to compare treatment effects. Average daily gain, feed efficiency, and carcass characteristics did not differ (P = 0.15 to 0.96) across dietary treatments. Adipose tissue saturated fatty acids were greater (P = 0.04) for Controls but were not different (P = 0.36) in muscle. Trans-vaccenic acid (18:1(trans-11)) increased (P < 0.0001) with safflower supplementation and was greater (P < 0.0001) in Linoleate than in Oleate for both tissue types. Linoleate lamb had greater (P < 0.0001) PUFA than Oleate lamb in muscle and adipose tissue. Conjugated linoleic acids (CLA; cis-9, trans-11 and trans-10, cis-12) were greater (P < 0.0001) in muscle and adipose tissue of lambs fed safflower seeds. Lambs fed Linoleate had greater (P < 0.0001) CLA in adipose tissue and muscle than lambs fed Oleate. Saturated fatty acids were greater (P < 0.0001) in s.c. adipose tissue than in tailhead adipose tissue. Mono- and polyunsaturated fatty acids were greater (P < 0.0001) in tailhead adipose tissue than in s.c. adipose tissue. Weight percentages of 18:1(trans-11) ranked tailhead adipose tissue = KPH adipose tissue > s.c. adipose tissue and semitendinosus > longissimus, whereas CLA ranked tailhead adipose tissue > s.c. adipose tissue > KPH adipose tissue and semitendinosus > longissimus. Feeding mono- and polyunsaturated fatty acids increased tissue 18:1(trans-11) and CLA, which is a favorable change in regard to current human dietary guidelines.

Conjugated linoleic acid and trans C18:1 in muscle and adipose tissue of lambs fed supplements containing n-3 polyunsaturated fatty acids

Conjugated linoleic acids (CLA) occur in the milk and tissues of ruminants. Although cis-9, trans-11 CLA is an intermediate in the biohydrogenation of linoleic acid in the rumen, duodenal flows of CLA are very low (Scollan et al, 2001) and most CLA appears to be synthesised in tissues from trans-11 C18:1 (vaccenic acid) (Griinari et al, 2000). Trans C18:1 isomers are also produced in the rumen and their amounts are increased when the levels of dietary unsaturated fatty acids are raised. We have investigated the relationship of tissue levels of CLA and trans C18:1 in three breeds of lambs fed supplements of linseed or fish oil to increase trans C18:1.