Degummed crude canola oil, sire breed and gender effects on intramuscular long-chain omega-3 fatty acid properties of raw and cooked lamb meat

Background: Omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) confer important attributes to health-conscious meat consumers due to the significant role they play in brain development, prevention of coronary heart disease, obesity and hypertension. In this study, the ω3 LC-PUFA content of raw and cooked Longissimus thoracis et lumborum (LTL) muscle from genetically divergent Australian prime lambs supplemented with dietary degummed crude canola oil (DCCO) was evaluated. Methods: Samples of LTL muscle were sourced from 24 first cross ewe and wether lambs sired by Dorset, White Suffolk and Merino rams joined to Merino dams that were assigned to supplemental regimes of degummed crude canola oil (DCCO): a control diet at 0 mL/kg DM of DCCO (DCCOC); 25 mL/kg DM of DCCO (DCCOM) and 50 mL/kg DCCO (DCCOH). Lambs were individually housed and offered 1 kg/day/head for 42 days before being slaughtered. Samples for cooked analysis were prepared to a core temperature of 70 °C using conductive dry-heat. Results: Within raw meats: DCCOH supplemented lambs had significantly (P < 0.05) higher concentrations of eicosapentaenoic (EPA, 20:5ω3) and EPA+docosahexaenoic (DHA, 22:6ω3) acids than those supplemented with DCCOM or DCCOC; Dorset sired lambs contained significantly (P < 0.05) more EPA and EPA+DHA than other sire breeds; diet and sire breed interactions were significant (P < 0.05) in affecting EPA and EPA+DHA concentrations. In cooked meat, ω3 LC-PUFA concentrations in DCCOM (32 mg/100 g), DCCOH (38 mg/100 g), Dorset (36 mg/100 g), White Suffolk (32 mg/100 g), ewes (32 mg/100 g) and wethers (33 mg/100 g), all exceeded the minimum content of 30 mg/100 g of edible cooked portion of EPA+DHA for Australian defined ‘source’ level ω3 LC-PUFA classification. Conclusion: These results present that combinations of dietary degummed crude canola oil, sheep genetics and culinary preparation method can be used as effective management tools to deliver nutritionally improved ω3 LC-PUFA lamb to meat consumers

Omega-3 fatty acids, nutrient retention values, and sensory meat eating quality in cooked and raw Australian lamb

This study evaluated omega-3 intramuscular fatty acids in the longissimus thoracis et lumborum of commercially prepared Australian lamb loin chops. Meats, denuded of external fats were cooked by means of conductive dry-heat using a fry grilling hot plate, to a core temperature of 70 °C. An untrained consumer panel assessed meat appearance, aroma, tenderness, juiciness, taste and overall liking. Results showed no compositional alterations (P > 0.05) to omega-3 fatty acids due to cooking treatment, whereas on absolute terms (mg/100 g muscle) omega-3 fatty acids significantly (P < 0.05) increased. The mean EPA + DHA content of the cooked meat at 32.8 ± 2.3 mg/100 g muscle exceeded the minimum 30 mg/100 g per edible portion required for the defined Australian classification as 'source' long-chain (≥ C20) omega-3 for cooked lamb. A 3.4% intramuscular fat content in the initial raw meat was sufficient to maintain acceptable overall sensory eating quality. Results endorse the application of this cooking method to enable delivery of health beneficial long-chain omega-3 fatty acids of commercially prepared Australian lamb loin chops to consumers without impediments to sensory eating properties

Genetic variation in intramuscular fat of prime lamb supplemented with varying concentrations of degummed crude canola oil

The main objective of this study was to quantify the intramuscular fat (IMF) content of Longissimus thoracis et lumborum, biceps femoris and triceps brachii muscles in genetically divergent lambs supplemented with varying levels of degummed crude canola oil (DCCO). Over a nine-week feeding trial, twenty-four first-cross prime lamb progeny from Merino, Dorset and White Suffolk rams mated with purebred Merino ewes under the same nutritional management we re supplemented with one of three levels of wheat-based pellets with or without DCCO. The experimental treatments included the Control (1kg of plain wheat-based pellets without DCCO/head/day on dry matter basis), High (1kg of wheat-based pellets containing 50ml of DCCO/kg/head/day on dry matter basis) and Medium (500g of Control + 500g of High wheat-based pellets/head/day on dry matter basis). All lambs had a three-week adjustment period and had ad libitum access to lucerne hay and water. After nine weeks of supplementation, all experimental lambs were slaughtered at a commercial abattoir with the exception of four purebred Merino ewes retained in the flock for breeding purposes. IMF content was analysed using a 2:1 vol/vol ratio of chloroform/methanol extraction and precipitated with 10% potassium chloride. IMF content varied significantly with the level of DCCO supplementation (p<0.0125) and muscle type (p<0.0001). There were also highly significant interactions between sire breed and level of DCCO supplementation (P<0.0016), and muscle type and sex (P<0.0003) in IMF content. Prime lambs in the Control and Medium level of DCCO supplementation had the most IMF (3.18±0.12 and 3.28±0.14%, respectively) and the High treatment had the least (2.96±0.10%), suggesting a decrease in IMF as supplementation levels with DCCO increased. The Longissimus thoracis et lumborum had more IMF (3.69±0.11%) than the biceps femoris (2.87±0.11%)) and triceps brachii (2.90±0.12%) muscles. It was also evident that in ewes, the biceps femoris had the least IMF (2.4%) compared with Longissimus thoracis et lumborum (3.6%). This result indicates that supplementation of prime lambs with DCCO can be used as a management tool to vary the level of IMF content to suit different market specifications dictated by meat consumers. Whereas in themselves, sex and sire breed of lambs used in this study were not the primary drivers of IMF deposition, our results demonstrate that sheep farmers can modify their nutritional management and breed combinations by effectively utilizing appropriate sire breed and supplementation level combinations to manipulate the IMF content of various muscle types in ewe and wether prime lambs

Degummed crude canola oil supplementation affects fat depot melting points in purebred and first-cross Merino sheep

The objective of this study was to test the hypothesis that degummed crude canola oil (DCCO) will lower fat melting points (FMP) of both visceral and subcutaneous fats in lambs. Twenty-four lambs comprising purebred and first-cross Merino progeny from Dorset, White Suffolk and Merino sires mates to purebred Merino ewes were supplemented with varying levels of DCCO over a nine week period. The experimental treatment groups were: Control (1kg plain wheat-based pellets only), Medium (500g plain wheat-based pellets + 500g wheat-based pellets containing DCCO), and High (1kg wheat-based pellets containing DCCO at a concentration of 50ml/kg) supplementation levels. The flock comprised eight wether and ewe lambs per treatment. However, at the end of the trial, four Merino ewes were retained in the flock for breeding purposes, while the remaining twenty lambs were slaughtered in a commercial abattoir. Visceral fat samples were taken from the kidney region and subcutaneous fat samples from the Longissimus dorsi muscle. FMP was determined using temperature slip point methodology in the laboratory. DCCO had significant effects on the FMP of both subcutaneous (P 0.0002) and visceral (p<0.0001) fats, with the lowest FMP achieved at high levels of supplementation in both fat depots. Significant sire breed differences (p<0.0001) were also detected in which Dorset-sired progeny had the highest melting points in both fat depots. The results of this study indicate that within fat depots, DCCO supplementation produced softer fats with lower melting points, suggesting potentially healthier fats containing higher levels of unsaturated fatty acids

Nutritional value and sensory characteristics of meat eating quality of Australian prime lambs supplemented with pelleted canola and flaxseed oils: fatty acid profiles of muscle and adipose tissues

The effects of canola or flaxseed oil dietary supplementation on Longissimus thoracis et lumborum (LTL) muscle and visceral adipose tissue fatty acid (FA) profiles and meat sensory traits in Australian prime lambs from different breeds were investigated. Sixty lambs were fed one of the following pellet treatments: no oil (Control), 2.5% canola, 5% canola, 2.5% flaxseed and 5% flaxseed, balanced by breed (purebred Merino, and first-cross lambs from Corriedale rams mated to Merino ewes and White Suffolk rams mated to Corriedale ewes). Lambs were individually supplemented daily with 1 kg of oil-enriched wheat-based pellets throughout the 7-week feeding trial, after a 3-week adjustment period and an unlimited access to water and lucerne hay. At the end of the feeding trial, all animals were slaughtered. From each carcass, an LTL muscle sampled at the 12/13th rib interface and a visceral adipose tissue sampled from the vicinity of the liver were taken and subjected to fatty acid analysis. A separate LTL muscle sample was utilised for sensory evaluation of meat eating quality. The inclusion of 5% flaxseed oil significantly decreased n-6/n-3 ratio in both tissues. The muscle from lambs fed 5% oil supplements had higher omega-3 long-chain polyunsaturated FA (n-3 LC-PUFA) contents and reached the claimable health-benefitting value without deleterious sensory effects. The n-3 LC-PUFA component in visceral adipose tissue was negligible. Tissue FA profiles and sensory quality were influenced by lamb breed. There were significant interactions between oil supplementation levels and lamb breed on some visceral adipose FA and meat juiciness. These findings indicate that a combination of dietary manipulation and lamb genetics can be used as an effective management tool to deliver a nutritionally improved n-3 LC-PUFA lamb to consumers

Performance and carcass characteristics of Australian purebred and crossbred lambs supplemented with rice bran

Background\ud \ud This study examined the effects of dietary supplementation with rice bran, sire breed and gender on live animal performance and carcass characteristics in Australian crossbred and purebred Merino lambs.\ud \ud Methods\ud \ud Forty-eight lambs balanced by sire breed (Dorset, White Suffolk, Merino) and gender (ewe, wether) were randomly allocated into three dietary supplementation groups (Control- 24 lambs fed wheat/barley-based pellets, Low- 12 animals fed a 50/50 ratio of wheat-based/rice bran pellets, and High- 12 lambs fed rice bran pellets). The Rice bran pellets replaced 19% of the barley component of the feed. Animals were group-fed at the rate of 1000 g of the supplement per head per day with ad libitum access to lucerne hay as the basal diet and water. The duration of the feeding trial was 49 days with an initial 21-day adjustment period.\ud \ud Results\ud \ud Sire breed differences were evident for initial (p < 0.0002) and final (p < 0.0016) liveweights, hot carcass (p < 0.0030) and cold carcass (p < 0.0031) weights, as well as dressing percentage (p < 0.0078), fat thickness (p < 0.0467), yield grade (p < 0.0470) and rib eye area (p < 0.0022) with purebred Merino under-performing compared to the crossbreds. Concentrate feed conversion efficiency, costs per unit of liveweight gain and over the hooks income were comparable between treatments regardless of the observed trend where the high supplementation group tended to show lower feed intake (745.8 g/day) compared to both the control (939.9 g/day) and low supplementation groups (909.6 g/day). No significant differences (p > 0.05) were observed between treatments for live animal performance, carcass characteristics, gender and their second-order interactions.\ud \ud Conclusions\ud \ud Results indicate that Rice bran can be utilised as a cost-effective supplementary feed source in genetically divergent sheep over a 49-day feeding period without detrimental effects on overall live animal performance or carcass characteristics