Dietary citrus pulp reduces lipid oxidation in lamb meat

This study investigated the effect of replacing cereal concentrates with high levels of dried citrus pulp in the diet on lamb meat oxidative stability. Over 56 days, lambs were fed a barley-based concentrate (Control) or concentrates in which 24% and 35% dried citrus pulp were included to partially replace barley (Citrus 24% and Citrus 35%, respectively). Meat was aged under vacuum for 4 days and subsequently stored aerobically at 4 °C. The Control diet increased the redness, yellowness and saturation of meat after blooming (P < 0.01). Regardless of the level of supplementation, dietary dried citrus pulp strongly reduced meat lipid oxidation over 6 days of aerobic storage (P < 0.001), while colour parameters did not change noticeably over storage and their variation rate was not affected by the diet. In conclusion, replacing cereals with dried citrus pulp in concentrate-based diets might represent a feasible strategy to naturally improve meat oxidative stability and to promote the exploitation of this by-product.     

Effects of finishing period length with vitamin E supplementation and alfalfa grazing on carcass color and the evolution of meat color and the lipid oxidation of light lambs

Indoor-kept concentrate-fed light lambs (n = 54) were supplemented with 500 mg of dl-α-tocopheryl acetate/kg concentrate for 0, 10, 20 and 30 d before slaughtering at 22–24 kg BW. Simultaneously, 8 lambs with their dams were alfalfa-grazed and the lambs were slaughtered at the same weight. The age at slaughter and carcass characteristics were more affected by grazing than by supplementation with α-tocopherol. The grazing lambs had similar α-tocopherol levels to the lambs fed concentrate with dl-α-tocopheryl acetate for 10 days before slaughter. The length of the feeding period affected the evolution of the color, delaying the blooming and discoloration of the meat. Feeding lambs α-tocopherol enriched concentrate during the last 10 days of life or grazing them on alfalfa drastically diminished the lipid oxidation of the meat. Alfalfa grazing is a feasible alternative to increase light lamb meat shelf life without using additives.     

Dietary olive cake reduces the oxidation of lipids,including cholesterol,in lamb meat enriched in polyunsaturated fatty acids

Over 40 days, lambs were fed: concentrate (C), concentrate containing 20% linseed (L), concentrate containing 35% olive cake (OC), or concentrate containing 10% linseed and 17% olive cake (OCL). The polyunsaturated fatty acids (PUFA) and peroxidation index (PI) in phospholipids were increased by the L and OCL treatments (P = 0.007 and P = 0.003, respectively). The OC and OCL diets increased the concentration of tocopherol in muscle (P < 0.001). Compared to the OC and OCL diet, the L diet increased fatty acid oxidation, measured as conjugated dienes (CD; P = 0.003), peroxides (PV; P < 0.001) and TBARS (P = 0.002) in minced muscle over 11 days of storage in high-oxygen atmosphere. Also, the L diet increased (P < 0.001) the levels cholesterol oxidation products (COPs). In conclusion, feeding olive cake improved the oxidative stability of lamb meat and the combination of olive cake and linseed improved the fatty acid composition of meat without compromising its oxidative stability.     

Effects of linseed and quercetin added to the diet of fattening lambs on the fatty acid profile and lipid antioxidant status of meat samples

Thirty-two Merino lambs fed barley straw and a concentrate formulated either with palm oil (CTRL group) or with linseed (+ LS group), both alone or supplemented with quercetin (+ QCT group or + LS + QCT group) were used to assess the effects of these dietary supplements on meat quality attributes. After being slaughtered, the longissimus thoracis muscles were used to study the fatty acid (FA) profile in detail, whilst longissimus lumborum slices were stored under refrigerated conditions to determine the lipid stability. Linseed increased the content of highly unsaturated n − 3 long-chain fatty acid (20:5n − 3; 22:5n − 3; 22:6n − 3). Interestingly, a significant increment of rumenic acid content (9c,11t-18:2) was observed when this seed was administered together with dietary quercetin. Moreover, the feeding of quercetin resulted in a reduction in the proportion of saturated FA and a decrease in lipid peroxidation of meat when the lambs were fed linseed. In conclusion, from both a nutritional and a commercial (shelf-life) point of view, it may be useful to include a source of quercetin when lambs are fed linseed diets.     

Effect of the dietary supplementation of essential oils from rosemary and artemisia on muscle fatty acids and volatile compound profiles in Barbarine lambs

Eighteen Barbarine lambs (3 months of age), were assigned for 95 days to 3 treatments: six lambs were fed a barley-based concentrate plus oat hay ad libitum (control group, C); other lambs received the control diet plus essential oil (400 ppm DM) either of Rosmarinus officinalis (R400 group; n = 6) or of Artemisia herba alba (A400 group; n = 6). At slaughter the muscle longissimus dorsi was sampled and subjected to fatty acid and volatile organic compounds (VOC) analyses. The A400 lambs presented a greater amount of vaccenic, rumenic and linolenic acids and of polyunsaturated fatty acids (PUFA) in meat than the C and R400 animals. Essential oils supplementation did not affect meat VOC profile though the sesquiterpenes copaene and β-caryophyllene were detected only in the meat of R400 and A400 lambs. It is concluded that the supplementation of rosemary or artemisia essential oils does not produce detrimental effects on lamb meat VOC profile. The supplementation of artemisia can improve meat healthy properties.     

Antioxidant status,colour stability and myoglobin resistance to oxidation of longissimus dorsi muscle from lambs fed a tannin-containing diet

Fourteen lambs were individually penned for 60 days. Seven lambs (C) were fed a barley-based concentrate, while 7 animals (T) received the same concentrate supplemented with 8.96% (dry matter basis) quebracho (Schinopsis lorentzii) extract. Tannin supplementation extended colour stability of fresh longissimus dorsi muscle (LM) over 7 days of aerobic storage with lower changes in hue angle over time in LM from T-fed animals compared to C-fed lambs (P = 0.032). Muscle from T-fed lambs had lower metmyoglobin percentages (MMb%) than that from C-fed animals after 3 days of storage (P = 0.05) and tended to have slower rates of change in (K/S)₅₇₂ ÷ (K/S)₅₂₅ values (P = 0.07). Compared to the C diet, tannin supplementation increased the concentration of total phenols in muscle (+31.29%, P = 0.001) and resulted in a higher muscle antioxidant capacity measured by FRAP (+16.81%, P = 0.026) and TEAC (+24.81%, P = 0.001) tests. Furthermore, feeding tannins resulted in lower MMb% after nitrite-induced oxidation measured both at the meat surface (−10%, P = 0.012) and in a meat extract (−8.22%, P = 0.004).     

Animal performance and fatty acid composition of lambs fed with different vegetable oils

Twenty-seven lambs were used to investigate the effects of the inclusion of 4% hydrogenated palm oil (HPO) or sunflower oil (SFO) in the concentrate on animal performance, carcass and meat quality and fat characteristics and fatty acid composition. Animals (16.2 ± 0.27 kg initial weight) were fed concentrate (Control, HPO or SFO) and barley straw ad libitum and slaughtered at 25 kg. SFO lambs tended to eat less concentrate than HPO animals (P < 0.10). Neither HPO nor SFO affected any of the carcass characteristics studied, meat pH and meat and fat colour (P > 0.05). SFO decreased proportions of C16:0, C18:1 cis-11 and C18:3 (P < 0.05) and increased C18:1 trans (P < 0.001) and C18:2/C18:3 ratio (P < 0.05). Atherogenicity index was lower (P < 0.05) when SFO was included in the concentrate. HPO did not affected and SFO improved fatty acid composition of fattening lambs without affecting animal performance.     

Effect of dietary carnosic acid on the fatty acid profile and flavour stability of meat from fattening lambs

Thirty-two lambs were fed with barley straw supplemented by a concentrate alone, or a concentrate enriched with either vitamin E (VITE006: 0.6 g kg⁻¹ feed concentrate) or carnosic acid (CARN006: 0.6 g kg⁻¹ feed concentrate; or CARN012: 1.2 g kg⁻¹ feed concentrate). In order to elucidate the influence of the dietary supplementation of carnosic compared with a reference diet antioxidant (vitamin E), the animals were slaughtered and the longissimus thoracis were lyophilised to determine the FAs profile and the phenolic compounds. In addition, longissimus lumborum slices were stored in a modified atmosphere package for 3 days and then grilled to determine volatile compounds. Dietary carnosic acid did not modify the FAs profile, but had a clear effect on the production of volatile compounds, in a dose-dependent manner. These results have implications for the food industry, since dietary carnosic acid seems to extend the shelf life of lamb meat.     

Effect of production system on carcass measurements and meat quality of Kivircik lambs

Effect of production system on carcass and meat quality was investigated in four groups of lambs: i. W-C lambs were weaned between 45 and 60 days of age and then were fattened with concentrate feed until slaughter; ii. W-G-S lambs were weaned and then taken to pasture and wheat stubble; iii. UW-C lambs were fattened with concentrate feed and they suckled their dams until slaughter; iv. UW-G lambs were kept with their dams and were taken to pasture in the day-time. Hot carcass weight was 13.62, 12.52, 14.37 and 13.88 kg (P < 0.001), and dressing percentage was 55.24, 51.77, 57.83 and 55.38% (P < 0.001), for W-C, W-G-S, UW-C and UW-G lambs, respectively. Ultimate meat pH was higher in W-G-S lambs than lambs from W-C and UW-C systems (P < 0.05). W-G-S lambs had higher shear force value in longissimus dorsi muscle (P < 0.05) and lower meat lightness (P < 0.001) than those of other systems. Panellists gave the lowest sensory scores, except juiciness, to meat of W-G-S lambs.     

Effects of different sources of fat (calcium soap of palm oil vs. extruded linseed) in lactating ewes' diet on the fatty acid profile of their suckling lambs

The main objective of this study was to evaluate the effects of supplementing lactating ewe diets with extruded linseed on the fatty acid (FA) composition of intramuscular and subcutaneous fat depots of suckling lambs. Twenty-four pregnant Churra ewes were divided into two groups based on the milk production, age, body weight and parity, and assigned to one of two treatments. Each ewe of the Control treatment was supplemented with 70 g/day of FAs from a calcium soap of palm oil, while the other treatment group (Lin) was supplemented with 128 g/day of extruded linseed. All lambs were reared exclusively on milk and were slaughtered when they reached 11 kg live weight. FA profiles of ewe milk, lamb meat and subcutaneous adipose tissue were determined by GC. Lamb performance was not affected by the treatments. Muscle fat and adipose tissue from the Lin treatment showed higher proportions of polyunsaturated fatty acids (PUFA). The percentages of α-linolenic (C18:3 n − 3), docosahexaenoic (C22:6 n − 3), vaccenic (trans-11 C18:1) and rumenic (cis-9, trans-11 C18:2) acids in both fat depots were higher in Lin than in Control suckling lambs. Furthermore, meat fat from Lin carcasses displayed a lower n − 6/n − 3 ratio than Control samples. Intramuscular depots clearly showed a greater content of PUFA, including cis-9, trans-11 C18:2, and a lower n − 6/n − 3 ratio than subcutaneous fat. The results from this study demonstrate that dietary extruded linseed supplementation of lactating ewes enhances the nutritional quality of suckling lamb fat depots such as intramuscular and subcutaneous fats.     

Effect of concentrate level and slaughter body weight on growth performances,carcass traits and meat quality of Barbarine lambs fed oat hay based diet

This study was conducted to evaluate concentrate level (CL) and slaughter body weight (SW) effects on growth performances, carcass traits and meat quality of Barbarine lambs. Twenty-four weaned male lambs (23.1 kg), receiving an oat-hay based diet, were allotted into two groups. The LCL group received low concentrate level (300 g) and the HCL group received high concentrate level (600 g). Lambs were slaughtered at two prefixed weights (35 and 42 kg). For each group and each weight, six lambs were slaughtered. Lambs from HCL group had higher ADG, carcass yields, carcass compactness and subcutaneous fat thickness, and lower carcass meat proportion. CL increase did not affect meat pH, meat and fat color, chemical and fatty acid composition. Late slaughtering improved carcass yields and increased carcass adiposity. However, it did not affect carcass meat proportion and shoulder tissue composition. SW had effect on meat color and fatty acid composition.     

Pre-rigor temperature and the relationship between lamb tenderisation,free water production,bound water and dry matter

The M. longissimus from lambs electrically stimulated at 15 min post-mortem were removed after grading, wrapped in polythene film and held at 4 (n = 6), 7 (n = 6), 15 (n = 6, n = 8) and 35 °C (n = 6), until rigor mortis then aged at 15 °C for 0, 4, 24 and 72 h post-rigor. Centrifuged free water increased exponentially, and bound water, dry matter and shear force decreased exponentially over time. Decreases in shear force and increases in free water were closely related (r² = 0.52) and were unaffected by pre-rigor temperatures.     

Influence of feeding systems on cortisol levels,fat colour and instrumental meat quality in light lambs

Forty-eight lambs were fed as follows: GR, lambs and dams grazed perennial pasture; GR+S, the same as GR except that lambs had access to concentrate; DRL-GRE, lambs in drylot and dams in rationed grazing; DRL, lambs with dams were stall-fed. DRL-GRE and DRL lambs were weaned at 45 days of age. Lambs were slaughtered when they reached 22–24 kg of live weight. Plasma cortisol concentration was determined three times before slaughter. Subcutaneous fat and meat colour, and texture were analysed.     

The effect of the change from a herbage- to a concentrate-based diet on the oxidative stability of raw and cooked lamb meat

Over 89 days, 10 lambs (S) were fed concentrates and hay in stall, while 9 lambs (P) grazed at pasture. Two groups of 9 animals grazed at pasture until switching to a concentrate-based diet for 14 or 37 days before slaughter (P-S14 and P-S37). The fat content of longissimus dorsi muscle (LM) increased with increasing duration of concentrate feeding (P = 0.05). As a consequence, the concentration of polyunsaturated fatty acids (PUFA) and of the highly peroxidisable (HP) PUFA in the polar lipids was similar between treatments. Lipid oxidation in fresh LM over 8 days of storage was affected by the diet (P < 0.0005) with the P-S37 and P treatments producing, respectively, the highest and the lowest TBARS values. The P treatment reduced TBARS in cooked minced LM over 2 days of storage and no difference was found between the P-S14, P-S37 and S treatments. Colour stability of fresh LM was not noticeably affected by the dietary treatment.     

Effects of the inclusion of sodium bicarbonate and sugar beet pulp in the concentrate for fattening lambs on acid-base status and meat characteristics

Thirty-six young Merino lambs (15.3 kg live weight) were allocated into four equal groups to study the effects of the inclusion of sodium bicarbonate (‘Bic’, 0 vs. 2%) and sugar beet pulp (‘SBP’, 0 vs. 12%) in the concentrate on meat characteristics. Lambs were fed barley straw and concentrate ad libitum. When they reached 25 kg a blood sample was taken and the animal slaughtered. After 24 h meat characteristics (pH, colour, water holding capacity, Warner–Bratzler shear force, chemical and fatty acid – ‘FA’ – composition) were measured on M. longissimus thoracis et lumborum. SBP replacing 24% of the barley in the concentrate caused an increase in shear force (P < 0.05) and saturated FA (P < 0.05), decreasing meat unsaturated FA (P < 0.05). SB increased blood base excess (P < 0.05) and meat yellowness (P < 0.05) and decreased meat pH (P < 0.05), without altering any other meat characteristics.     

Carcass characteristics of feedlot lambs fed crude glycerin contaminated with high concentrations of crude fat

Thirty non-castrated male lambs with 20 ± 2.3 kg average body weight (BW) were randomly assigned to five treatments consisted of different dietary concentrations of crude glycerin (CG; 0, 3, 6, 9 and 12% on DM basis) to evaluate the effects on performance, carcass and meat quality traits. A quadratic effect was observed for performance (P = 0.04), final BW (P < 0.01) and hot carcass weight (P < 0.01). No effects of CG were observed (P > 0.05) on carcass pH neither on shear-force, cooking loss and ether extract content in longissimus. The inclusion of CG tended to reduce the Zn content in meat (P = 0.09). The data suggests that CG (36.2% of glycerol and 46.5% of crude fat) may be used in diets of finishing lambs with concentrations up to 3% without negative effects on performance and main carcass traits. Moreover, inclusion of CG seems to not affect quality and safety of meat for human consumption.     

The effect of conditioning period on loin muscle tenderness in crossbred lambs with or without the Texel muscling QTL (TM-QTL)

A Texel muscling quantitative trait locus (TM-QTL) has been identified on chromosome 18, which increases loin muscling, but may also have a negative impact on mechanically-measured loin tenderness in crossbred lambs, depending on conditioning time. This study investigated the influence of a range of conditioning times (3, 5, 7 or 9 days) on the effect of TM-QTL on loin muscle tenderness. Using Texel rams heterozygous for TM-QTL, mated to non-carrier Mule ewes, heterozygous (n = 45) and wild-type (n = 50) crossbred lambs were produced. Weight of the valuable Longissimus lumborum muscle was higher in TM-QTL carriers than non-carriers, when compared at a fixed age (+11.5%; P = 0.038), with the same trend at a fixed carcass weight (+10.2%; P = 0.064). Toughness, measured by shear force, was significantly higher in samples from TM-QTL carriers than non-carriers, after conditioning for 3 days (P = 0.002), 5 days (P = 0.003) or 7 days (P = 0.03), but was not significantly different after 9 days of conditioning (P = 0.32). Compared to non-carrier lambs, the proportion of samples above consumer acceptability thresholds for toughness was greater in the TM-QTL carrier lambs after 3 and 5 days of conditioning, similar at 7 days, but lower at 9 days. The results suggest that the negative effect of TM-QTL on loin tenderness in crossbred lambs can be overcome by conditioning for more than 7 days. Marketing of TM-QTL carrier lambs through companies that use enhanced processing protocols could be beneficial, due to higher loin muscle weights, without negative effects on meat quality.     

Quercetin dietary supplementation of fattening lambs at 0.2% rate reduces discolouration and microbial growth in meat during refrigerated storage

Thirty-two Merino lambs fed barley straw and a concentrate formulated either with palm oil (CTRL group) plus quercetin (QCT group) or flaxseed (FS group) plus quercetin (FS-QCT group) were used to assess the effects of this flavonoid on meat quality attributes. The animals were slaughtered after being fed for at least 5 weeks with the experimental diets. Chemical composition of longissimus thoracis (LT) muscle was not different among treatments. The longissimus lumborum (LL) samples of QCT and FS-QCT groups revealed lower discolouration (hue angle) when compared to the CTRL and FS lambs (P < 0.05), whereas extract release volume (ERV) and microbiological data jointly suggest that flaxseed and quercetin may reduce the growth of microbial populations responsible for meat spoilage in quadriceps femoris (QF).     

The effects of immunological castration against GnRH with recombinant OL protein (Ovalbumin-LHRH-7) on carcass and meat quality characteristics,histological appearance of testes and pituitary gland in Kıvırcık male lambs

The aims of the study were to investigate the effects of immunization against GnRH using OL protein (Ovalbumin-LHRH-7) on feedlot performance, carcass, meat quality and some reproductive traits in K?v?rc?k ram lambs. Ram lambs in the immunization (I, n = 7) group were immunized against GnRH using OL protein and boosted 2 weeks later. Control (C, n = 7) group was not treated. The animals were kept at pasture for 6 weeks after the first immunization, subjected to a 70 day fattening program, and then slaughtered. Growth performance, various carcass and meat quality characteristics were not affected from the immunization. GnRH immunization induced GnRH antibody production, suppressed testosterone production and testicular growth (P < 0.01). Testicular structure was negatively affected from the immunization, but not pituitary. These results suggest that immunization against GnRH with OL could be an alternative castration technique in ram lambs without negatively affecting carcass and meat quality characteristics.