B.W.B. Holman

Growth and body conformation responses of genetically divergent Australian sheep to Spirulina (Arthrospira platensis) supplementation

The hypothesis that supplementation with Spirulina will increase liveweight, growth and body conformation with significant interactions between sire breed and sex was tested using purebred Merino weaners and first-cross weaners from Merino dams sired by Dorset, Black Suffolk and White Suffolk rams under the same pasture-based management system. Our experimental objective was to evaluate the effects of varying levels of Spirulina supplementation, sire breed and gender on liveweight and body conformation traits. We utilized a complete randomized block experimental design balanced by 4 sire breeds, 3 supplementation levels and 2 sexes in which weaned prime lambs with an average liveweight of 37.6 ± 5.2 kg and body condition score of 3.1 ± 0.4 at 6 months of age were balanced by sire breed and gender and randomly allocated into 3 treatments (8 lambs per treatment) – the control group grazing without Spirulina (0%), low (10%wt/vol) and high (20%wt/vol) Spirulina. Lambs in the low and high Spirulina treatment groups were drenched daily with Spirulina prior to being released for grazing with the control group of lambs over a 6-week trial period, following a 3-week adjustment phase. Weekly measurements of chest girth, withers height, body length, body condition score and liveweight were taken. Mixed linear model procedures in SAS with sire breed, sex, Spirulina level and their second order interactions as fixed effects and sire as a random variable, were used for statistical analysis. Spirulina level significantly influenced lamb liveweight (P<0.018), body condition score (P<0.001) and body length (P<0.015). Lambs on Spirulina levels of 10% recorded the highest mean liveweight of 41.9 ± 0.7 kg. Spirulina levels of 20% did not significantly improve liveweight compared to the control group (0%). Highly significant sire breed interactions with Spirulina level (P<0.001) resulted in the heaviest (47.08 kg) and lightest (35.14 kg) average liveweights in Black Suffolk-sired crossbreds and purebred Merino lambs respectively, supplemented at the 20% Spirulina level. Body conformation (P<0.001) and liveweight (P<0.014) responses to Spirulina supplementation significantly varied between ewe and wether lambs. It was evident that a cost-effective supplementation strategy with Spirulina for optimal liveweight gains in weaner lambs was achieved at the 10% level. These findings will aid sheep farmers in making informed choices about appropriate sire breed and gender combinations in their enterprises when supplementing with Spirulina for growth improvement as a strategic pathway for the early attainment of market weights in prime lambs. We concluded that based on the empirical experimental evidence within the scope of this study, the tested hypothesis is acceptable.

Effect of dietary supplementation with Spirulina on the expressions of AANAT, ADRB3, BTG2 and FASN genes in the subcutaneous adipose and Longissimus dorsi muscle tissues of purebred and crossbred Australian sheep

BackgroundThe demand for healthy, lean and consistent meat products containing low saturated fatty acid content and high quality polyunsaturated fatty acids (PUFA), especially long-chain (≥C20) omega-3 PUFA, has increased in recent times. Fat deposition is altered by both the genetic background and dietary supplements, and this study aimed to assess the effect of dietary Spirulina supplementation levels on the mRNA expression patterns of genes controlling lipid metabolism in the subcutaneous adipose tissue (SAT) and Longissimus dorsi (ld) muscle of Australian crossbred sheep.MethodsTwenty-four weaned lambs belonging to four breeds under the same management conditions were maintained on ryegrass pasture and fed three levels of Spirulina supplement (control, low and high). In terms of nutrient composition, Spirulina is a nutrient-rich supplement that contains all essential amino acids, vitamins and minerals. It also is a rich source of carotenoids and fatty acids, especially gamma-linolenic acid (GLA) that infer health benefits. After slaughter, subcutaneous adipose tissue (SAT) and ld samples were subjected to mRNA extraction and reverse transcription using quantitative polymerase chain reaction (RT-qPCR) to assess the mRNA expression levels of the Aralkylamine N-acetyltransferase (AANAT), Adrenergic beta-3 receptor (ADRB3), B-cell translocation gene 2 (BTG2) and Fatty acid synthase (FASN) genes, which are associated with lipid metabolism.ResultsBoth low and high Spirulina supplementation levels strongly up-regulated the transcription of all the selected genes in both SAT and ld tissues (mostly in the subcutaneous adipose), but sheep breed and sex did not influence the gene expression patterns in these tissues.ConclusionsThe evidence indicates that high Spirulina supplementation level resulted in a decrease in intramuscular fat content in Australian purebred and crossbred sheep due to the enhanced production of melatonin in sheep muscle tissues and strong up-regulation of mRNA expression of BTG2 in SAT which negatively affected fat deposition. In contrast, low Spirulina supplementation level strongly up-regulated the ADRB3 and FASN genes responsible for fat production. These findings are consistent with the observed phenotypic data suggesting that low Spirulina supplementation level can increase lamb production, with higher long-chain PUFA content.

Improving assessment practice through cross-institutional collaboration: An exercise on the use of OSCEs

Abstract Background: This study was undertaken to improve assessment practice on OSCEs through collaboration across geographically dispersed medical schools in Australia. Methods: A total of eleven OSCE stations were co-developed by four medical schools and used in summative 2011 and 2012 examinations for the assessment of clinical performance in the early clinical and exit OSCEs in each school’s medical course. Partial Credit Rasch Model was used to evaluate the psychometric properties of the shared OSCE data. Evaluation of the quality assurance reports was used to determine the beneficial impact of the collaborative benchmarking exercise on learning and teaching outcomes. Results: The data for each examination demonstrated sufficient fit to the Rasch model with infit mean square values ranging from 0.88 to 0.99. Person separation (1.25–1.63) indices indicated good reliability. Evaluation of perceived benefits showed that the benchmarking process was successful as it highlighted common curriculum areas requiring specific focus and provided comparable data on the quality of teaching at the participating medical schools. Conclusion: This research demonstrates the validity of the psychometric data and benefits of evaluating clinical competence across medical schools without the enforcement of a prescriptive national curriculum or assessment.

Effect of level of Spirulina supplementation on the fatty acid compositions of adipose, muscle, heart, kidney and liver tissues in Australian Dual-Purpose lambs

Abstract This study investigated the effect of level of Spirulina supplementation on the fatty acid (FA ) compositions of subcutaneous adipose, longissimus dorsi muscle, kidney, heart, and liver tissues in purebred and crossbred Australian Merino sheep. Forty-eight lambs sired by Black Suffolk, White Suffolk, Dorset and Merino rams were assigned into 4 treatment groups of daily Spirulina supplementation levels per lamb of 0 mL (control), 50 mL (low), 100 mL (medium) and 200 mL (high) referred to as 0, 5, 10 and 20% groups. The lambs were slaughtered after 9 weeks of supplementation and heart, kidney, adipose, liver and muscle tissue samples were collected. The results demonstrated significant variations in growth and body conformation traits and tissue and organ FA composition in response to the Spirulina supplementation. The medium-level Spirulina treatment group increased the ω-3 and ω-6 polyunsaturated fatty acid (PUFA ) composition in all tissues and organs significantly. The results suggest the use of medium level (100 mL/head/day) of Spirulina supplementation in order to increase lamb production with more ω-3 and ω-6 PUFA and therefore higher nutritional meat quality.

Single nucleotide polymorphisms of the ovine ADRB3 gene in crossbred Australian sheep supplemented with spirulina (Arthrospira platensis) cyanobacterial microalgae

The adrenergic-receptor beta3 (ADRB3) gene is an obesity gene that is involved in the regulation of energy balance and a variety of physiological functions by increasing lipolysis and thermogenesis. Spirulina (Arthrospira platensis) is a blue-green cyanobacterial alga containing 60-70% protein with an extensive history of human consumption, and more recently, inclusion in animal feeds. We had earlier demonstrated that low level oral supplementation by drenching prime lambs with 100 mL/head/day of 1g of Spirulina powder dissolved in 10 mL of water (10%wt:vol) increased live weight and body conformation measurements in Black Suffolk (BS) x Merino crossbred sheep. The hypothesis that genetics-nutrition interactions between sheep breeds with fewer mutations at the ADRB3 locus and an optimal Spirulina supplementation level will increase lean meat production was tested in the current study. Forty-eight crossbred Australian prime lambs sired by four rams of diverse breeds under the same pasture-based management conditions were subjected to a nine-week feeding trial with Spirulina, followed by genomic DNA extraction and single nucleotide polymorphism (SNP) analysis. Eleven SNPs in both the coding and noncoding regions of the ovine ADRB3 gene were detected. Nine of the SNPs were in exon I and two in the intron. Variations in SNP frequencies were highly significant (P <0.0001) between all sheep breeds. The maximum and minimum number of SNPs were found in purebred Merinos (4.83) and Black Suffolk x Merino (BS) crossbreds (1.67). In total, one indel and six transverse mutations were detected that resulted in six amino acid substitutions. BS crossbreds had the lowest frequency of mutation and amino acid substitutions in their population in agreement with our hypothesis. In conclusion, BS sheep genetics matched with low level (100 mL/head/day) of Spirulina supplementation can lead to higher meat production with less fat content in a typical pasture-based sheep production system.

Wool quality traits of purebred and crossbred Merino lambs orally drenched with Spirulina (Arthrospira platensis)

The objective of this study was to evaluate the effect of Spirulina supplementation, sire breed and sex on the wool characteristics of purebred and crossbred Merino weaned lambs under a single pasture-based management system. Lambs sired by Merino, White Suffolk, Dorset, Black Suffolk breeds were randomly allocated into 3 treatments – the control group grazing without Spirulina (0 mL), low (100 mL) and high (200 mL) Spirulina groups. All lambs were kept as a single mob in paddocks, grazed for 9 weeks and wool samples analysed. Differences in wool quality between the control and supplemented groups were not significant (P>0.05). However, sire breed significantly (P<0.001) influenced fibre diameter, spinning fineness, comfort factor and fibre curvature with purebred Merinos having superior wool quality than crossbreds. Wethers grew higher quality wool than ewes. Spirulina has a potential as an alternative supplementary bioresource in dual-purpose sheep feeding because it does not compromise wool quality in supplemented weaner lambs.

Spirulina Supplementation, Sire Breed, Sex and Basal Diet Effects on Lamb Intramuscular Fat Percentage and Fat Melting Points

The effects of Spirulina supplementation, sire breed, sex and basal diet on intramuscular fat percentage (IMF) and fat melting point (FMP) in crossbred and purebred Merino lambs were investigated. Over two consecutive years, a total of 48 lambs was randomly allocated into feeding trials that utilised either ryegrass or Lucerne hay basal diets. Each treatment group had 8 lambs balanced by sire breed (Black Suffolk, Dorset, Merino, White Suffolk), sex (ewes, wethers), and Spirulina supplementation level (CONTROL - unsupplemented, LOW 50ml, MEDIUM – 100ml, and HIGH – 200ml). Each feeding trial lasted for 9-weeks after 21 days of adjustment. Post-slaughter, IMF content of the Longissimus dorsi et lumborum muscle was determined using solvent extraction and FMP measured using the ‘slip-point’ method. Spirulina supplementation level influenced both IMF content and FMP in which MEDIUM Spirulina supplementation led to a decrease in IMF (1.98%) and FMP (42.97°C) compared to 3.18% and 44.44°C, respectively, in the LOW supplementation treatment group. Sire breed was a significant source of variation in FMP as purebred Merinos had the highest (45.63°C) and Black Suffolk crossbreds the lowest (41.53°C). Ewe lambs had higher IMF than wether lambs (2.52 vs 2.12%). Lambs on the ryegrass basal diet had lower IMF and FMP than their counterparts on Lucerne. Significant interactions between sire breed and supplementation level suggest a variety of nutritional management combinations that prime lamb producers can utilise to optimise meat quality for increasingly health-conscious consumers.