Meat quality of lambs (hair and wool) slaughtered at different live weights

Partial substitution of alfalfa hay by Berberis vulgaris leaf modulated the growth performance, meat quality and antioxidant status of fattening lambs

BACKGROUND

Undoubtedly, global warming has caused a decrease in the production of agricultural commodities. This problem has increased the price of animal feed due to competition with human consumption. Meanwhile, the physiology of ruminants gives them the ability to use by-products and agricultural waste and supply their requirements for growth, maintenance and even production. Berberis vulgaris is a plant native to Iran, and after separating the fruit, its waste (mainly leaf) is unused and causes environmental pollution. The leaves of this plant contain significant amounts of phenolic compounds, alkaloids and anthocyanins that have antioxidant properties.

OBJECTIVES

This experiment was conducted with the aim of determining the chemical properties of barberry leaves, such as crude protein, phenolic compounds, tannins and alkaloids. The effects of substituting of B. vulgaris leaf (BVL) in the diet on performance characteristics of fattening Baluchi lambs were evaluated. The quality and antioxidant status of meat and blood parameters such as glucose, cholesterol, blood urea nitrogen and liver enzymes were investigated.

MATERIAL AND METHODS

A total of 21 male of 5-6 months old lambs with a mean body weight of 30.60 ± 1.28 kg were randomly assigned to one of three dietary treatments with different levels of BVL: 1-diet without BVL (control), 2-diet containing 7.5% BVL (BVL7.5), and 3-diet containing 15% BVL (BVL15; dry matter [DM] basis). Blood samples were harvested after overnight fasting from the jugular vein at 0, 28, 56 and 84 days. The lambs were slaughtered after 84 days of feeding trial and longissimus dorsi (LD) muscle was dissected. Meat quality and antioxidant stability status were measured.

RESULTS

15% substitution of alfalfa hay by BVL (BVL15) increased DM intake) and decreased average daily gain (p ≤ 0.05). The LD muscle (p ≤ 0.05), liver (p ≤ 0.01) and plasma (p ≤ 0.05) samples of lambs fed either BVL7.5 or BVL15 displayed a greater total antioxidant capacity than that of lambs fed the control diet. Also, malondialdehyde concentration was decreased in plasma (p ≤ 0.01) and LD muscle of lambs (p ≤ 0.05) fed both BVL7.5 and BVL15. In addition, higher a* and C* values (p ≤ 0.05) were observed in the meat of lambs fed BVL15 than those fed with the control, while the lightness (L*) in BVL15 was lower, compared to other experimental diets CONCLUSIONS: Overall, our results indicated that 7.5% substitution of alfalfa hay by BVL may positively modulate the antioxidant status of fattening lambs and improve the colour stability of meat without negative effects on performance characteristics.

Effects of Dairy Lambs' Rearing System and Slaughter Age on Consumer Liking of Lamb Meat and Its Association with Lipid Content and Composition

The effects of the rearing system (artificially vs. naturally milk-fed) and the slaughter age (3-weeks milk-fed vs. 3-months pasture-fed) on consumer liking of East-Friesian-cross dairy lamb Longissimus lumborum muscle and its association with lipid content and composition were evaluated. The artificially reared lambs were removed from their dams at 2−3 days of age and reared with cow milk. Intramuscular fat content (2.8%) was similar between treatments. Only 3 of the 25 fatty acids evaluated were influenced by the rearing system and 15 by the slaughter age. The rearing system had a minor impact (p < 0.10), but the slaughter age had a major (p < 0.01) impact on consumer liking. All consumers preferred on average meat from 3-weeks-old lambs. However, based on overall liking scores, Cluster-1 (60% of consumers) preferred meat from 3-weeks-old lambs driven by all sensory attributes but mostly tenderness, whereas Cluster-2 preferred meat from 3-months-old lambs driven by flavor only, indicating a preference for stronger flavor from older lambs finished on pasture. Meat fatty acid profile and consumer liking were not influenced by the rearing system but by lamb slaughter age, showing a niche product opportunity for the 3-weeks milk-fed lambs.

Impact of Romanov breed lamb gender on carcass traits and meat quality parameters including biogenic amines and malondialdehyde changes during storage

The present study aims to evaluate the effect of Romanov breed lamb gender on carcass traits and meat quality parameters, as well as on the formation of biogenic amines (BAs) and malondialdehyde during meat storage. Obtained results revealed that lamb gender had a significant influence on sternum/breastbone, ribs, right shoulder, and bones of the back leg. Significantly higher lightness (by 3%) was found for male meat; however, higher redness of female meat was observed (by 7.7%). In all cases, a lower pH was obtained for female meat. Significantly higher cooking loss (by 38%) was found for male meat. However, gender was not a significant factor in lamb meat proximate composition, or for BAs and cholesterol content. The gender of animals had a significant influence on 10‐heptadecenoic (C17:1), linoleic (C18:2n – 6), total polyunsaturated FA, and total trans isomers content in meat. A significantly higher concentration of malondialdehyde was found in female lamb meat (by 43.4% and 56.8% in fresh and after 3 months of storage at −18°C, respectively) compared to males. Finally, the obtained results supplement the scarce database about the characteristics of Romanov breed meat of different gender and this is beneficial for lamb breeders and meat industry in order to obtain a better quality production.

Carcass and Meat Quality of Lambs from Thin-Tailed and Fat-Tailed Breeds at Five Different Slaughter Weights

In lamb production, deciding the optimal slaughter weight (SW) has great importance on product quality. The aim of the study was to determine the optimum SW for lambs from a thin-tailed breed (Kivircik) and a fat-tailed breed (Kangal Akkaraman) in order to get high-quality meat and carcass. Kivircik (n=60) and Kangal Akkaraman (n=59) lambs were allotted to five SW groups (20, 28, 36, 44 and 52 kg). In Kivircik lambs, backfat thickness and fatness score gradually increased in parallel with the increase in SW, while the increase in the tail fat and kidney knob and channel fat (KKCF) proportions were observed by up to 36 kg. In Kangal Akkaraman lambs, evident increases in fatness parameters, except tail fat proportion, were observed when the SW increased from 44 kg to 52 kg. Meat pH, Warner Bratzler shear force (WBSF) and cooking loss values were not influenced by SW in lambs of both breeds. As SW increased in Kivircik lambs, there was a significant decrease in meat lightness and an increase in yellowness. In Kangal Akkaraman breed, lambs slaughtered at 20 kg and 28 kg had higher L* values, and lower a* and C* values than those of other SW groups. In Kivircik lambs, the total PUFA proportion and the ΣPUFA/ ΣSFA ratio were lower in SW-44 and SW-52 groups than those of SW-20 and SW-28 groups. Decreases of these parameters were in SW-52 group in Kangal Akkaraman lambs. In meat samples of both breeds, SW-52 groups had a lower Σn-3 proportion and a higher Σn-6 / Σn-3 ratio than other SW groups. In Kivircik lambs, the panellists evaluated the meat of SW-20 and SW-28 groups as tender compared to those in SW-44 and SW-52 groups. In Kangal Akkaraman breed, flavour intensity in the meat of SW-52 lambs was higher than those of SW-20 and SW-28 groups. Results of the study indicate that slaughtering of lambs at 20 kg and 28 kg in both breeds provided better meat quality but caused lower carcass weight. Therefore, slaughtering Kivircik and Kangal Akkaraman lambs at 20 kg and 28 kg live weight might be recommended especially to farmers, who aim to obtain high-quality lamb meat. In this case, it should not be ignored that the amount of meat produced will be less. On the other hand, slaughtering lambs at about 44 kg weight could be recommended to farmers, who aimed to obtain as much quality lamb carcasses as possible without any negative influence on meat quality.

The inclusion of detoxified castor bean meal in sugarcane silage increases the carcass weight and the content of unsaturated fatty acids in lamb meat

The aim of this study was to evaluate the performance and meat quality of lambs fed sugarcane silage containing increasing levels of detoxified castor bean meal (DCBM). Twenty-four Santa Inês male sheep were used, with initial body weight of 25.34 ± 2.57 kg, distributed in a completely randomized design with four treatments (0, 70, 140, and 210 g/kg of DCBM in the sugarcane silage). Intake and digestibility of dry matter (DM) and crude protein (CP) were positively influenced (P < 0.05) by the levels of DCBM. There was a linear increase (P < 0.05) on the intake and digestibility of neutral detergent fiber with the inclusion of DCBM. The daily and total gains showed a quadratic effect (P < 0.05) with the inclusion of DCBM, with a maximum point of 241.64 g/d and 18.12 kg at the level of 161.9 g/kg of DCBM. There was a linear increase (P < 0.01) on the hot carcass with the inclusion of DCBM. The inclusion of DCBM did not influence (P > 0.05) the levels of total lipids (2.1%) in lamb meat, but the levels of oleic acid (C18:1 n-6c) and total monounsaturated fatty acids presented a quadratic effect (P < 0.05). It is recommended to include 160 g/kg of detoxified castor bean meal in sugarcane silage.

Meta-analysis of the relationship between collagen characteristics and meat tenderness

Meta-analysis methods were used to investigate the effects of collagen content, solubility and pyridinoline cross-link content on Warner-Bratzler shear force (WBSF) and sensory tenderness in major meat species. Data was collected from the literature on pork, beef and lamb and analyzed independently for each species. The beef data was categorized into subgroups according to muscle (loin and other muscle) and age (young, <18 months and old, ≥18 months). The results showed that in beef, collagen content and pyridinoline cross-link content were positively correlated with WBSF and negatively with sensory tenderness, while collagen solubility was negatively correlated with WBSF. The correlation coefficients were greater in other beef muscles than loin. Significant correlations between collagen content and tenderness attributes were observed in old beef animals. However, non-significant relationships and large variations were found in pork and lamb. More studies with various muscles and ages are required for an in-depth understanding of the relationship between collagen characteristics and meat tenderness.

Effect of Age and Breed on Carcass and Meat Quality Characteristics of Beni-Guil and Ouled-Djellal Sheep Breeds

Two hundred eight sheep, belonging to two main breeds of eastern Morocco, “Beni-Guil” and “Ouled-Djellal,” were investigated for carcass traits and meat quality. The objective of this study is to determine the effects of breed and age at slaughter on carcass traits and meat quality. The animals were slaughtered at three age classes: milk teeth, animals with two adult teeth, and adult animals. Dressing percentage, carcass measurements, compactness indices, carcass shrinkage parameter, conformation scores, fatness state, fat consistency, fat and meat colour, and pH were measured 24 hours postmortem. The results showed that the dressing percentage, carcass measurements, and compactness indices increased with slaughter age (p < 0.001). Furthermore, the effect of breed was higher for Ouled-Djellal breed of carcass characteristics (p < 0.01). However, no significant effect was observed for carcass shrinkage parameter. The longissimus lumborum muscle was used to determine the meat colour, which ranged from 23.89 to 21.96, while the ultimate pH ranged from 5.70 to 5.82. These results were influenced by age at slaughter (p < 0.05) but not influenced by breed. Breed and age at slaughter had a significant influence on carcass traits (p < 0.001). The present study provided a new insight into the effect of breed and age at slaughter on carcass and meat traits of both “Beni-Guil-PGI” and Ouled-Djellal sheep breeds.

Liveweight and Sex Effects on Instrumental Meat Quality of Rubia de El Molar Autochthonous Ovine Breed

Simple Summary

A total of 84% of the autochthonous livestock breeds in Spain are in danger of extinction. This decline is mainly produced because they are not very productive and the farmers have been oriented to the most productive breeds, neglecting the rest. There are many factors that push us to conserve autochthonous breeds with little census. These animals are very adapted to their environment, so they are the ones that best exploit the geographical characteristics of their area; besides, their products have a high quality and these breeds have very beneficial genetic components: they are a source of very useful and not sufficiently known gene variants that make them a genetic heritage of undoubted value. If they become extinct, we would be losing an irreplaceable genetic quality. Rubia de El Molar sheep, an autochthonous breed of Madrid, Spain, is currently in serious danger of disappearing. In this work, the meat quality of lambs from Rubia de El Molar breed was studied to test both weight and sex effects on meat quality, assessed by means of instrumental methods. This is the first work that studies the instrumental quality of Rubia de El Molar suckling lamb meat.

Abstract

The effects of sex and weight on instrumental meat quality characteristics of Rubia de El Molar autochthonous ovine breed were studied. Four weight groups (10, 15, 20 and 25 kg, each of the groups with seven males and seven females) were assessed. A decrease of longissimus thoracis muscle (LT) lightness from 43.39 for 10 kg lambs to 38.84 for 25 kg group was observed. LT redness and yellowness indices and chromaticity values increased as weight increased. The percentage of juice expelled increased from 11.52 (10 kg) to 17.15 (15 kg). The percentage of intramuscular fat in biceps femoris (BF) and supraespinatus (SE) muscles increased as weight increased. Warner–Bratzler shear force (WBSF) in raw meat and hardness in cooked meat increased as liveweight increased. However, a decrease in the amount of soluble collagen in quadriceps femoris (QF), biceps femoris (BF) and infraespinatus (IE) muscles was observed as weight increased. Sex effect was only observed for intramuscular fat content in QF and BF muscles (2.4% in males and 2.9 in females) and WBSF in raw meat (26.12 N for males and 21.25 N for females). Weight had a greater effect than sex on Rubia de El Molar meat quality characteristics.

Affordable Processing of Edible Orthopterans Provides a Highly Nutritive Source of Food Ingredients

Edible orthopterans (grasshoppers, crickets, and locusts) are major delicacies, especially across sub-Saharan Africa. Their promotion as food ingredients is increasingly gaining momentum. This study evaluates the nutritional profiles of three widely consumed orthopterans: Gryllus bimaculatus, Locusta migratoria, and Schistocerca gregaria after blanching and oven-drying. All three species had high protein (65.3, 54.2, and 61.4% on a dry matter (DM) basis for G. bimaculatus, L. migratoria, and S. gregaria, respectively) and fat contents. Oleic (22.9-40.8%) and palmitic (26.1-43.0%) were the two most abundant fatty acids. All essential amino acids (in mg/100 g protein) were present, with glutamic acid (120-131), alanine (90.2-123), and leucine (82.3-84.6) being the most abundant. The minerals (in mg/100 g dry matter) potassium (796-1309) and phosphorus (697-968) were moderately high, and iron (4.60-7.31), zinc (12.7-24.9), manganese (0.40-7.15), and copper (1.20-4.86) were also observed in the samples. Vitamin B12 contents were high (0.22-1.35 µg/100 g dry matter). Our findings demonstrate that the excellent nutritional profile of the three processed insects could serve as promising alternative ingredients for improving food and nutritional security.

Dual energy X-ray absorptiometry precisely and accurately predicts lamb carcass composition at abattoir chain speed across a range of phenotypic and genotypic variables

Dual energy X-ray absorptiometry (DEXA) is an imaging modality that has been used to predict the computed tomography (CT)-determined carcass composition of multiple species, including sheep and pigs, with minimal inaccuracies, using medical grade DEXA scanners. An online DEXA scanner in an Australian abattoir has shown that a high level of precision can be achieved when predicting lamb carcass composition in real time. This study investigated the accuracy of that same online DEXA when predicting fat and lean percentages as determined by CT over a wide range of phenotypic and genotypic variables across 454 lambs over 6 kill groups and contrasted these results against the current Australian industry standard of grade-rule (GR) measurements to grade carcasses. Lamb carcasses were DEXA scanned and then CT scanned to determine CT Fat % and CT Lean %. All phenotypic traits and genotypic information, including Australian Sheep Breeding Values, were recorded for each carcass. Residuals of the DEXA predicted CT Fat % and Lean %, and the actual CT Fat % and Lean % were calculated and tested against all phenotypic and genotypic variables. Excellent overall precision was recorded when predicting CT Fat % (R2 = 0.91, RMSE = 1.19%). Small biases present for sire breed, sire type, dam breed, hot carcass weight and c-site eye muscle area could be explained by a regression paradox; however, biases among kill group (-0.73% to 1.01% for CT Fat %, -1.48% to 0.76% for CT Lean %) and the Merino sire type (0.36% for CT Fat %, -0.73% for CT Lean %) could not be explained by this effect. Over the large range of phenotypic and genotypic variation, there was excellent precision when predicting CT Fat % and CT Lean % by an online DEXA, with only minor biases, showing superiority to the existing Australian standard of GR measurements.

The effect of carcass weight on fatness and muscle and fat colour of male Ojinegra de Teruel light lambs

This study aimed to evaluate the effects of increases in lamb carcass weight in 1-kg steps from 8 to 11 kg on carcass fatness, muscle colour, subcutaneous and renal fat colour, tissue composition of the thoracic limb, and intramuscular fatty acid composition. Sixty-two carcasses from Ojinegra de Teruel male lambs fed concentrates ad libitum and barley straw were used. Both carcass scores and renal fat weight increased with carcass weight (P = 0.0001), but the percentage increase in renal fat weight was twice that of fat scores. Renal fat was prone to store carotenoids earlier than caudal fat, resulting in increased chroma. With increasing carcass weight, muscle colour became less light (decreased L* (P = 0.0001) and an increased in chroma scores (P = 0.001). Increments of 1 kg of carcass weight led to noticeable changes in the M. rectus abdominis colour, except at the increment from 10 kg to 11 kg. Slaughtering lambs at light weights was found to be advisable because renal fat is not a valuable part of the carcass. The lean percentage of the thoracic limb did not increase with carcass weight, as the increased muscle:bone ratio (P = 0.0001) was offset by an increased fat percentage (especially the intermuscular fat %). Changes with increasing carcass weight in the proportions of the main fatty acids in intramuscular fat were small. Moreover, intramuscular fat did not change in quantity or quality. However, when selling carcasses at heavier weights is preferred, achieving carcasses of 11 kg rather than 10 kg was found to be advisable because the deposition of fat in both was similar. Breeds that deposit fat earlier than the breed used in this study should be fed low-energy diets to improve carcass quality. This feeding strategy could also be considered if fat deposition differs between sexes.