Tedera is a valuable high-quality forage for sheep during summer–autumn. There is evidence that prior grazing experience of novel forages influences preference and haymaking of tedera improves preference by goats. In the first experiment, it was hypothesised that the voluntary feed intake (VFI) of fresh leaves and stems of tedera by sheep would be greater for experienced vs. naïve sheep. In the second experiment, it was hypothesised that the VFI of naïve sheep fed wilted leaves and stems of tedera would be greater than fresh leaves and stems of tedera. To test these hypotheses, adult Merino sheep were fed seven accessions of tedera, in two outdoor pen feeding experiments conducted consecutively. Each of six pens had 14 feeders, two for each accession, and two sheep. In experiment 1, three pens had sheep that had previously grazed tedera (experienced) and three pens had sheep with no experience (naïve), and all were fed fresh leaves and stems of the seven tedera accessions. Experiment 2 involved only naïve sheep, with three pens fed fresh leaves and stems and three pens fed wilted leaves and stems of the seven tedera accessions. Preference was measured each day for six days in experiment 1; and for five days in experiment 2 by calculating the average differences of feed offered and feed remaining from the feeders. In experiment 1, experienced sheep showed no difference in preference (average percentage eaten) in the first hour of each day compared to naïve sheep (70% vs. 56% DM intake (kg), p = 0.27). There was an increase in the amount eaten from the first to the last day for both groups, except for the intake of one accession that was reduced for the experienced sheep. In experiment 2, there was no statistical difference in preference between accessions. However, when the average percentage eaten by the experienced and naïve groups are combined, they are strongly correlated, with significant differences between accessions. Sheep did not eat more wilted tedera compared to fresh, which did not support our hypothesis. The only differences we found in sheep preference for tedera accessions occurred in experiment 1. Further studies to investigate seasonal differences in sheep preference between accessions is required and increased replication is needed to better determine the effect of prior grazing experience on the preference for tedera accessions.

The objective of the study was to determine if feeding the probiotic Bacillus amyloliquefaciens strain H57 ('H57 ') to young Merino wethers can improve their feed intake, productivity, energy metabolism and rumen fermentation parameters. Thirty-six Merino wethers were housed in individual pens and fed ad libitum a high-fibre pelleted diet (Control group, n = 18), or the same pelleted diet inoculated with H57 (H57 group, n = 18) for a four-week Treatment period. This was followed by a two-week Carry-over period when all wethers were fed the pelleted diet without H57. Intake of pellets was measured daily (dry matter intake, DMI), live weight (LW) and body condition score (BCS) were measured weekly, and the LW gain (LWG) and feed conversion ratio (FCR) were calculated from the DMI and LWG. During the six-week experimental period, samples of blood and rumen fluid were collected four times and analysed for blood enzymes, metabolites, hormones and rumen fermentation parameters. In the Treatment period, the H57 group had 25% larger final LW than the Control group (6.0 vs 4.8 kg, P = 0.045) and had a greater BCS (2.94 vs 2.44, P = 0.014) and DMI of pellets (1429 vs 1337 g/day, P = 0.033), resulting in a better FCR (6.8:1.0 vs 8.4:1.0, P = 0.049). The increases in final LW and BCS were most marked in the initial two weeks of the Treatment period, but persisted over the remaining two weeks and continued, albeit to a smaller extent, during the Carry-over period. Blood metabolites, enzymes and hormones did not differ between the two groups and were within the expected reference ranges for sheep. Rumen NH3 concentrations were elevated (P = 0.033) in the H57 group throughout the experiment, but overall the volatile fatty acid (VFA) concentrations were not different. B. amyloliquefaciens was present in H57 pellets throughout the Treatment period, and consequently was detected in the rumen fluid and faeces of the H57 group. In conclusion, young Merino wethers fed high-fibre pellets inoculated with H57 for four weeks grew faster, converted the pellets into final LW more efficiently and had a higher BCS than peers fed the same pellets without H57. This can be important when feeding high-fibre pellets to transition young Merino wethers onto a finishing diet. The mechanisms behind these responses remain to be elucidated.

Seasonal weight loss (SWL) is a major constraint to extensive animal production systems. The Australian sheep production is based on merino sheep, a European breed not tolerant to SWL. Tolerant alternative breeds such as the fat-tailed Damara and the Dorper have been increasingly used in Australia and elsewhere, due to their robustness. The aim of this study was to understand the mineral profile of muscle and liver tissues of Australian Merino, Damara and Dorper, when subjected to SWL in order to understand SWL-tolerance physiology. Twenty-four lambs were divided randomly between growing (control) and nutritionally restricted groups for each breed. The trial lasted 42 days. Animals were weighed bi-weekly and at the end of the trial, lambs were slaughtered. Liver and muscle samples were taken immediately after slaughter. Mineral assessment was carried out using inductively coupled plasma-optical emission spectrometry. Analysis of variance showed mineral concentrations were generally increased in the muscle of restricted animals, mainly because of fat tissue mobilization. An increase in Zn and Fe concentrations indicates an increase of enzymatic activity in the liver of restricted sheep as well as differential abundance of Fe-containing proteins. High concentrations of Cu in the liver of Dorper indicate higher ability to accumulate this element, even under SWL.

Seasonal weight loss (SWL) is a primary constraint for farmers in the Mediterranean and tropics. One cost-effective solution to SWL is utilizing breeds like the Damara sheep that have adapted to deal with nutritional stress. Previous studies concluded that one of the adaptation mechanisms of SWL is a specialized fatty acid metabolism. Accordingly, hepatic-mitochondrial proteomes were compared across two different breeds (24 sheep total, Merino, n = 12 and Damara, n = 12) and two different diets (restricted vs unrestricted diet, 6 per breed, per diet, 24 total). Mitochondrial-proteins were isolated and relatively quantified using Blue native PAGE / 2D-electrophoresis and then analyzed via mass spectrometry. The tool ReviGO summarized the proteomes' gene-ontology terms. A total of 50 proteins were identified with 7 changing significantly in abundance (ANOVA p-value<0.05). Specific abundance patterns of corticosteroid and inflammatory response-associated proteins such as annexin and glutamate dehydrogenase suggests that the Damara has an unusual inflammation response when subjected to SWL in addition to its unique metabolism. All significant proteins warrant further study; Annexin in particular shows promise as a potentially useful biomarker.

The effect of feed restriction on the liver protein profiles of two different breeds of sheep was studied. We compared Merino with the Damara, breeds with respectively low and high tolerance to nutritional stress. Each breed was grouped into two nutritional treatments: restricted (12-14% loss of live weight) and control (maintenance). The trial lasted 42 days. Animals were sacrificed and liver samples subjected to label free shotgun proteomics. The resultant proteins had both their fold change and statistical significance in an unpaired t-test calculated to identify differential protein abundance. The tool WebGestalt was utilized to perform an Overrepresentation Enrichment Analysis (ORA) for gene ontology terms associated with the significant proteins. We further validated shotgun proteomics findings using a selected reaction monitoring (SRM)-based targeted proteomics approach, where similar trends in regulation were obtained for a subset of relevant proteins across an independent cohort of animals. Results confirm that Damara has adapted to nutritional stress by mobilizing stored fatty acids within adipose tissue and converting them to energy more efficiently than Merino. Finally, Merino had an overabundance pattern primarily directed to protein synthesis pathways. Regulated proteins identified may be used as a basis for marker selection towards tolerance to nutritional stress. Biological significance: Sheep are one of the most important livestock animals. They remain however poorly understudied and described. Seasonal weight loss (SWL) due to pasture scarcity during the dry season is one of the most limiting conditions to ruminant production in the tropics. To counter SWL, farmers may use supple. mentation, expensive or difficult to implement. A more suitable long-term solution would be to use breeds that are naturally adapted to nutritional stress. This work contrasts two breeds with different levels of tolerance to SWL, the Damara and the Merino, respectively well and poorly adapted. Comparison is conducted at the level of the hepatic tissue and using label free proteomics. This work identifies a series of pathways in the liver of the Damara via label free proteomics that suggest a unique fatty acid metabolic process within this breed. Proteins that have increased abundance in the Damara in association with fatty acid metabolism may be used as potential markers of tolerance to nutritional stress. This research will pave the way for more viable, long-term solutions for farmers facing annual production problems due to drought in the tropics and the Mediterranean region.

Seasonal Weight Loss (SWL) is one of the most pressing issues in animal production in the tropics and Mediterranean. This work aims to characterize muscle proteome changes as a consequence of SWL in meat producing sheep, using a label-free proteomics approach. We compare three breeds: the Australian Merino (SWL susceptible), the Damara (SWL tolerant) and the Dorper (SWL intermediate tolerance). We identified 668 proteins of the sheep proteome, 95 with differential regulation. Also we observe that the more vulnerable to SWL a breed is, the more differential abundance proteins we find. Protein binding was the most frequently altered molecular function identified. We suggest 6 putative markers for restricted nutritional conditions independently of breed: ferritin heavy-chain; immunoglobulin V lambda chain; transgelin; fatty acid synthase; glutathione S-transferase A2; dihydrodiol dehydrogenase 3-like. Moreover, we suggest as related to SWL tolerance: S100-A10 Serpin A3-5-like and Catalase, subject however to necessary validation assays. The identification of SWL-tolerance related proteins using proteomics will lead to increased stock productivity of relevant interest to animal production, particularly if identified at the muscle level, the tissue of economic importance in meat production. BIOLOGICAL SIGNIFICANCE:Seasonal Weight Loss (SWL) is the most pressing issue in animal production in the tropics and the Mediterranean. To counter SWL, farmers often use animal breeds that have a natural ability to withstand pasture scarcity. Here we study the sheep muscle proteome at the muscle level, the tissue of economic importance in meat production. Furthermore, the identification of proteins that change their abundance in response to SWL using proteomics can contribute to increased stock productivity of relevant interest to animal production. We identified 668 proteins of the sheep proteome. We demonstrate that the following proteins are affected by restricted nutritional conditions: ferritin heavy chain; immunoglobulin V lambda chain; transgelin; fatty acid synthase; glutathione S-transferase A2; dihydrodiol dehydrogenase 3-like. Furthermore, S100-A10, Serpin A3-5-like and Catalase are proteins that changed their abundance in response to SWL. Nevertheless, it is important to highlight that Catalase values for the merino breed were close to significance and therefore catalase validation is of utmost importance.

Seasonal Weight Loss (SWL) is an important constraint, limiting animal production in the Tropics and the Mediterranean. As a result, the study of physiological and biochemical mechanisms by which domestic animal breeds respond to SWL is important to those interested in animal breeding and the improvement thereof. To that end, the study of the proteome has been instrumental in gathering important information on physiological mechanisms, including those underlying SWL. In spite of that, little information is available concerning physiological mechanisms of SWL in production animals. The objective of this study was to determine differential protein expression in the muscle of three different breeds of sheep, the Australian Merino, the Dorper and the Damara, each showing different levels of tolerance to weight loss (low, medium and high, respectively). Per breed, two experimental groups were established, one labeled "Growth" and the other labeled "Restricted." After forty-two days of dietary treatment, all animals were euthanized. Muscle samples were then taken. Total protein was extracted from the muscle, then quantified and two-dimensional gel electrophoresis were conducted using 24 cm pH 3-10 immobiline dry strips and colloidal coomassie staining. Gels were analyzed using Samespots® software and spots of interest were in-gel digested with trypsin. The isolated proteins were identified using MALDI-TOF/TOF. Results indicated relevant differences between breeds; several proteins are suggested as putative biomarkers of tolerance to weight loss: Desmin, Troponin T, Phosphoglucomutase and the Histidine Triad nucleotide-binding protein 1. This information is of relevance to and of possible use in selection programs aiming towards ruminant animal production in regions prone to droughts and weight loss.

Sheep are a valuable resource for meat and wool production. During the dry summer, pastures are scarce and animals face Seasonal Weight Loss (SWL), which decreases production yields. The study of breeds tolerant to SWL is important to understand the physiological mechanisms of tolerance to nutritional scarcity, and define breeding strategies. Merino, Damara and Dorper sheep breeds have been described as having different levels of tolerance to SWL. In this work, we assess their liver and muscle metabolomes, and compare the responses to feed restriction. Ram lambs from each breed were divided into growth and feed restricted groups, over 42 days. Tissue metabolomes were assessed by 1H-NMR. The Dorper restricted group showed few changes in both tissues, suggesting higher tolerance to nutritional scarcity. The Merinos exhibited more differences between treatment groups. Major differences were related to fat and protein mobilization, and antioxidant activity. Between the Damara groups, the main differences were observed in amino acid composition in muscle and in energy-related pathways in the liver. Integration of present results and previous data on the same animals support the hypothesis that, Dorper and Damara breeds are more tolerant to SWL conditions and thus, more suitable breeds for harsh environmental conditions.

Seasonal weight loss is the major constraint to animal production in the tropics. To counter seasonal weight loss, the use of breeds better adapted to it is of major importance. Damara sheep are an important breed in tropical animal production, as they are not only able to tolerate seasonal weight loss, but also have a characteristic fat-tail adipose tissue, often discarded, but that may be of interest to the food industry. The objective of this work is to determine the effect of weight loss on mineral profiles (zinc, manganese, iron, potassium, sodium, magnesium and calcium) in the fat-tail of Damara sheep. The trial lasted 42 days and was conducted in Western Australia. Twenty-four Damara sheep lambs were randomly allocated to an underfed (growth rate –100 g/day) and a control group (growth rate 100 g/day). Upon slaughter, fat-tail adipose tissue was sampled and analysed by atomic absorption spectrophotometry for mineral content. The results showed no significant differences regarding minerals concentrations/quantities, with the exception of zinc and calcium concentrations that were higher in the restricted group, likely as a consequence of feed restriction and a decrease in fat tissue amount. In conclusion, we have quantified for the first time several minerals in Damara sheep fat-tail and demonstrated that reducing their bodyweight does not affect mineral quantity in fat-tails of Damara sheep.

BACKGROUND: Muscle fatty acid profile reflects the body condition of animals and has a noticeable effect on meat quality. Herein, longissimus dorsi muscle of three different sheep breeds, Damara (a fat-tailed breed), Dorper and Australian Merino sheep, was analysed for fatty acid composition. The three breeds were subjected to two distinctive feeding levels (ad libitum and restricted feeding) over 42 days.RESULTS: The Damara sheep revealed several differences compared to the other two breeds, namely a higher concentration of polyunsaturated fatty acids, which can be related to being a fat-tailed breed. Even in restricted feeding conditions, this breed revealed the highest levels compared to Merino and Dorper sheep respectively, of linoleic acid (+31% and +28%), linolenic acid (+97% and +51%), eicosapentaenoic acid (EPA) (+65% and +37%), docosapentanenoic acid (DPA) (+31% Merino) and dodosahexanenoic acid (DHA) (+63% and +77%). EPA, DPA and DHA are three omega-3 fatty acids, with described beneficial characteristics.CONCLUSION: With this work we show other qualities (higher levels of the omega-3 fatty acids, EPA, DPA and DHA) of Damara meat that might present this breed as an interesting alternative for animal production in semi-arid climates. (C) 2015 Society of Chemical Industry

Bituminaria bituminosa is a drought-tolerant, perennial legume that has been used for centuries as a part of the mixed sward in grazing systems around the Mediterranean sea and cut and carried' to feed as hay to dairy goats in the Canary Islands; varieties albomarginata and crassiuscula, commonly known as tedera, are native only to the Canary Islands. In south-western Australia, tedera will likely be directly grazed as green plants to help fill the feed gap in summer-autumn, due to its drought tolerance and capacity to retain green leaves. There are no reports of ill-effects of grazing tedera in its native environment; however, tedera is never the sole diet there. Hence, before proceeding to grazing trials it was important to conduct pen feeding studies with a sole diet of tedera. Sheep fed fresh tedera exclusively for 34 days readily consumed the forage and remained in good health, as reflected by a standard set of blood chemistry parameters. Furthermore, while the intake of the sheep fed tedera may not have been ad libitum (similar to 1.0 kg DM/head.day), they maintained their liveweight (42.5 kg) and body condition (condition score 3) throughout the experiment. This is the first experiment to measure the in vivo digestibility and nitrogen balance of sheep fed fresh' tedera forage. During the metabolism study, the in vivo digestibility of organic matter in the dry matter of the fresh tedera was similar to that of lucerne chaff (59% vs 55%) when the sheep fed lucerne chaff had their intake restricted to that of those fed tedera.

Seasonal weight loss is the main limitation to animal production worldwide, significantly affecting the productivity of milk, meat and wool farms, particularly in drought-prone areas of the world where most of the large-scale wool production farms are located. Although the effect of nutritional status on wool quality parameters has been extensively studied, little is known on how it affects wool protein composition. Here, a proteomic approach has been applied to study changes in fiber structure and protein composition in wool from merino sheep subjected to experimentally induced weight loss. Results indicate that there is a significant reduction in the fiber diameter of wool from the animals on a restricted diet over a 42-day period. At the same time, significant increases in the expression of the high sulfur protein KAP13.1 and proteins from the high glycine-tyrosine protein ICAP6 family in the wools from the animals on the restricted diet were also detected. Such findings have strong implications for the wool industry that favors finer wool.Biological significanceSeasonal weight loss caused by poor pasture availability has strong effects on wool productivity parameters and quality traits. In this work we determine that experimentally induced weight loss causes a decrease in fiber diameter associated with an increase in the level of high sulfur protein KAP13.1 and proteins from the high glycine-tyrosine protein KAP6 family. The implication of this is that decreasing the fiber diameter of the wool by this process could result in a fiber reduced prickle but with reduced wearability and appearance retention. (C) 2014 Elsevier B.V. All rights reserved.

Seasonal weight loss (SWL) is the most pressing constraint in ruminant production systems in tropical climates. SWL is controlled using supplementation, which is costly and difficult to implement in extensive systems, or using breeds adapted to tropical hot dry climates, like the Damara and Dorper. Albeit 15 years in Australia, little is known on how these sheep compare to Australian Merino. Here, the responses of the Damara, Dorper and Merino breeds to nutritional stress were compared. Seventy-two 6-month-old ram lambs, 24 from each breed, were allocated to growth (gaining 100 g/day) or restricted diets (losing 100 g/day, 85 % of maintenance needs). Animals were weighed and carcass and meat characteristics determined. Results point out to the existence of important differences between the three genotypes, in particular between the Merino and the Southern African breeds. Additionally, Merino ram lambs seem to have been more influenced by SWL than the other two, with consequences on meat characteristics.

Fat tailed sheep breeds are known for their adaptation to nutritional stress, among other harsh production conditions. Damara sheep, native to Southern Africa, have recently been exported to other areas of the world, particularly Australia, aiming to produce lamb in semi-arid regions. Damaras have a unique hanging fat tail, a fat depot able to be mobilized under nutritional stress. In this article we perform an in-depth characterization of the fatty acid profiles of the fat tail in underfed and control Damara rams. Profiles were very similar between experimental groups, with the exception of palmitic acid (16:0) that was lower (P = 0.014) in underfed animals. However, the most striking result was the very high proportions of non-terminal branched chain fatty acids found in the fat tail adipose tissue, as well as the gastrocnemius muscle of Damara rams. The muscle of Dorper and Merino rams used in the same experiment did not present non-terminal branched chain fatty acids, suggesting that Damara rams have a unique lipid metabolism. Herein, we interpret this trait relating it to a higher ability of Damara sheep to digest fibrous fodder and to putative differences in the propionate metabolism by comparison to other sheep breeds.

Seasonal Weight Loss (SWL) is the most relevant constraint to animal production in the tropics and Mediterranean countries (Almeida et al., 2006). In fact, during the dry season characteristic of such climates animals may lose up to 20% of their initial weight, significantly affecting their productive performances with strong economic implications (Almeida et al., 2006).

Seasonal Weight Loss (SWL) poses a serious limitation to animal production in Tropical and Mediterranean climates, strongly conditioning agriculture. The study of the physiological and molecular mechanisms by which different sheep breeds respond to SWL is of capital interest with important implications in animal selection. Recently, the use of proteomic approaches has allowed a much greater insight on the molecular mechanisms at the protein level in a vast array of physiological mechanisms including those underlying SWL. The objective of this study is to determine differential protein expression in the liver of three breeds of sheep that show different tolerance levels to SWL: Australian Merino (highly susceptible), Damara (tolerant) and Dorper (intermediate). Liver samples were obtained from both control and underfed, weight-loosing animals of the three breeds. Total protein was extracted; quantified and two-dimensional gel electrophoresis was conducted using 24 cm pH 3-10 Immobiline dry strips (1). Gels were analyzed using Imagemaster platinum software (Amersham). A total of 67 spots were considered to show differential expression for this study and data is currently being processed for identification using MALDI-TOF/TOF data in order to determine physiological implications for sheep selection. Acknowledgments: A special thank to all fellow researchers from the Mass Spectometry Group at ITQB/UNL-Oeiras, Portugal, for all the helpful tips on work methods and protocols and also Tanya Kilminster, Tim Scanlon (DAFWA, WA, Australia) for kindly supplying the liver samples. References: