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BackgroundThis 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.MethodsForty-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.ResultsSire 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.ConclusionsResults 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.

BackgroundOmega-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.MethodsSamples 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.ResultsWithin 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.ConclusionThese 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.

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Abstract: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 firstcross Merino progeny from Dorset, White Suffolk and Merino sires mated to purebred Merino ewes were supplemented with varying levels of DCCO over a nine-week period. The experimental treatment groups were: Control (1kg plain wheatbased 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 were taken 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 likely to contain higher levels of unsaturated fatty acids.