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Abstract: This study tested the effects of Spirulina supplementation level, basal diet and their interactions with sire breed and sex on liveweight, body conformation and growth traits in dual-purpose Australian lambs. In two concurrent feeding trials utilising typical pasture-based and simulated-drought basal diets, a total of 48 lambs was randomly allocated to treatment groups of Spirulina supplementation levels (CONTROL – 0ml, LOW – 50ml, MEDIUM – 100ml and HIGH – 200ml), balanced by sire breed (Black Suffolk, Dorset, Merino and White Suffolk) and sex (ewes and wethers). In both feeding trials, Spirulina was supplemented daily for 9-weeks, following a 3-week adjustment phase. Weekly data of liveweight and body conformation measurements; chest girth (CG), wither height, body length, and body condition score (BCS), were taken throughout the trials. These were transformed into changes between initial and final periods of the feeding trial. Average daily liveweight gain (ADG) was computed from the differences in liveweight divided by duration in days. All data were analysed using Factorial ANOVA analysis in SAS. Medium and high Spirulina supplementation levels were found to improve the liveweight and ADG of White Suffolk- and Merino-sired lambs on simulated-drought basal diets. BCS improved with Spirulina supplementation in lambs on simulated-drought basal diets. Under typical pasture-based basal diet, supplemented lambs had comparatively higher CG, BCS, liveweight and ADG than their counterparts on simulated-drought basal diets. These findings are of practical significance to the sheep industry because of the potential selection aid to Australian farmers in identifying the usefulness of Spirulina as a supplement and the optimal sire breed choice for the best performance response that is cost-effective when using dietary protein-rich supplements for their dual-purpose prime lamb operations. [Copyright &y& Elsevier]

The Warner–Bratzler shear force (WBSF) of 335 lamb m. longissimus lumborum (LL) caudal and cranial ends was measured to examine and simulate the effect of replicate number ( r : 1–8) on the precision of mean WBSF estimates and to compare LL caudal and cranial end WBSF means. All LL were sourced from two experimental flocks as part of the Information Nucleus slaughter programme (CRC for Sheep Industry Innovation) and analysed using a Lloyd Texture analyser with a Warner–Bratzler blade attachment. WBSF data were natural logarithm (ln) transformed before statistical analysis. Mean ln(WBSF) precision improved as r increased; however the practical implications support an r equal to 6, as precision improves only marginally with additional replicates. Increasing LL sample replication results in better ln(WBSF) precision compared with increasing r , provided that sample replicates are removed from the same LL end. Cranial end mean WBSF was 11.2 ± 1.3% higher than the caudal end. [ABSTRACT FROM AUTHOR]

• Microalgae (Chlorella vulgaris) increased the omega-3 long-chain PUFA concentration in fresh lamb meat. • Microalgae supplementation did not affect lamb growth performance, wool or meat quality parameters. • Microalgae supplementation did not affect rumen fermentation parameters. This study evaluated the effect of different levels of fresh microalgae (Chlorella vulgaris) in a feedlot diet on the performance, carcass traits, and meat quality of lambs. Forty-five, four-month-old wether lambs were randomly assigned to one of three dietary treatments: 1) CONTROL, without algae; 2) MEDIUM, with 0.5 % dry matter (DM) algae; or 3) HIGH, with 1 % DM algae added to a basal diet consisting of barley hay and commercial feedlot pellets in a 41:59 ratio. The lambs were fed for 98 days and then slaughtered. Microalgae supplementation did not affect (P ≥ 0.09) growth performance, wool quality, rumen fermentation parameters, carcass weight, dressing percentage, or subcutaneous fat thickness of the lambs. However, microalgae supplementation at 0.5 % DM increased (P ≤ 0.05) the concentration of alpha-linolenic acid (ALA; C18:3n-3), arachidic acid (C20:0), and total omega-3 long-chain (n-3 LC) fatty acids in the longissimus lumborum et thoracis (LTL) muscle of lambs, compared to the CONTROL. Intramuscular fat (%) was similar between the CONTROL and the MEDIUM group (av. 3.65 %), but was lower (P = 0.044) in the HIGH group (3.1 %). Therefore, our results indicate that adding 0.5 % DM microalgae to lamb diets can increase the levels of alpha-linolenic acid and total n-3 LC PUFA in fresh lamb meat without affecting lamb performance or carcass characteristics. [ABSTRACT FROM AUTHOR]

A small angle X-ray scattering (SAXS) synchrotron was used to evaluate 100 ovine m . longissimus lumborum , representing lamb (n = 50) and sheep (n = 50). The diffraction of X-rays gives information on muscle myofibril structure and fat content. The linear relationships between SAXS measures with measures such as, shear force, intramuscular fat content (IMF) and collagen content/solubility, were investigated. A relationship was found between the d-spacing of the actin/myosin fibril spacing (SAX1 and SAX2) and the cross sectional area of the rhombohedral unit cell (Cell area) and shear force after 1 and 5 day ageing. There was a positive relationship between IMF and a SAXS Fat area measure. There was a muscle site effect on SAX1, SAX2 and Cell area, with the cranial site having a larger distance between myofibrils. The potential of SAXS as a powerful research tool to determine not only the structural components of ovine tenderness, but also the fat content related to IMF is evident. [ABSTRACT FROM AUTHOR]