Phenotypic blood glutathione concentration and selenium supplementation interactions on meat colour stability and fatty acid concentrations in Merino lambs

The interaction between blood glutathione (GSH) and supplementation of selenium (Se, 2.5 mg/kg diet) on meat colour and fatty acids concentrations was studied. Forty eight Merino lambs selected for high blood GSH (HGSH) or low GSH (LGSH) concentration were used. They were fed individually with or without Se supplement for 8 weeks. There were interactions (P< 0.05) between GSH and Se on the colour stability (as w630 nm/w580 nm ratio) of m. longissimus (LD), m. semimembranosus (SM) and m. semitendinosus. Without Se supplementation the ratio was higher in HGSH than LGSH group. However, the difference was reduced with Se supplement. Polyunsaturated and n-3 fatty acids in SM and LD were higher in HGSH than in LGSH group (P< 0.05), and did not change with Se supplement. Se supplementation increased Se content in LD (P< 0.001) and the lungs (P< 0.05), but had no influence in the heart

Quantum walks: a comprehensive review

Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important result: the computational universality of both continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing Journa

The mobilisation of fat in response to adrenaline is greater in merino ewes with higher breeding values for coefficient of variation of fibre diameter

Biological indicators that can be used to predict the sensitivity of animals to environmental changes are of interest to the sheep industry for economic and welfare reasons. The coefficient of variation of fibre diameter (HCVFD) is a potential indicator of environmental sensitivity and tends to be negatively correlated with fatness. To further understand the association of HCVFD with the sensitivity to the environment, exogenous adrenaline was administered to Merino ewes with known breeding values for fleece weight and HCVFD on three occasions throughout the breeding cycle. The mobilisation of fat in response to Adrenaline was greater in high HCVFD ewes and this effect was consistent across pregnancy, lactation and non-breeding states. Merino sheep with low breeding values for HCVFD are likely to mobilise less fat in response to stress and are therefore likely to be less sensitive to changes in the grazing environment. Therefore HCVFD is thus a potential indicator of environmental sensitivity in sheep

Selection for superior growth advances the onset of puberty and increases reproductive performance in ewe lambs

The reproductive efficiency of the entire sheep flock could be improved if ewe lambs go through puberty early and produce their first lamb at 1 year of age. The onset of puberty is linked to the attainment of critical body mass, and therefore we tested whether it would be influenced by genetic selection for growth rate or for rate of accumulation of muscle or fat. We studied 136 Merino ewe lambs with phenotypic values for depth of eye muscle (EMD) and fat (FAT) and Australian Sheep Breeding Values at post-weaning age (200 days) for live weight (PWT), eye muscle depth (PEMD) and fat depth (PFAT). First oestrus was detected with testosterone-treated wethers and then entire rams as the ewes progressed from 6 to 10 months of age. Blood concentrations of leptin and IGF-I were measured to test whether they were related to production traits and reproductive performance (puberty, fertility and reproductive rate). In total, 97% of the lambs reached first oestrus at average weight 39.4 ± 0.4 kg (mean ± s.e.m.) and age 219 days (range 163 to 301). Age at first oestrus decreased with increases in values for PWT (P < 0.001), and concentrations of IGF-I (P < 0.05) and leptin (P < 0.01). The proportion of ewe lambs that achieved puberty was positively related with increases in values for EMD (P < 0.01), FAT (P < 0.05) or PWT (P < 0.01), and 75% of the ewe lambs were pregnant at average weight 44.7 ± 0.5 kg and age 263 days (range 219 to 307). Ewe lambs that were heavier at the start of mating were more fertile (P < 0.001) and had a higher reproductive rate (P < 0.001). Fertility and reproductive rate were positively correlated with increases in values for EMD (P < 0.01), FAT (P < 0.05), PWT (P < 0.01) and leptin concentration (P < 0.01). Fertility, but not reproductive rate, increased as values for PFAT increased (P < 0.05). Leptin concentration increased with increases in values for EMD (P < 0.001), FAT (P < 0.001), PWT (P < 0.001), PEMD (P < 0.05) and PFAT (P < 0.05). Many of these relationships became non-significant when PWT or live weight was added to the statistical model. We conclude that selection for genetic potential for growth can accelerate the onset of puberty and increase fertility and reproductive rate of Merino ewe lambs. The metabolic hormones, IGF-I and leptin, might act as a physiological link between the growing tissues and the reproductive axis

Differences in survival and neonatal metabolism in lambs from flocks selected for or against staple strength

In the field, we found that lamb mortality was lower (P < 0.01) in a flock selected for wool staple strength (SS+) than in a flock selected against staple strength (SS-), or a random-bred control flock (R); mortality rates calculated from 4200 records were 17.0, 22.8, and 24.1%, respectively. The proportion of twins was similar in all flocks, but birth weights differed (P < 0.01), being 4.40, 4.25, and 4.14 kg, respectively. Biochemical profiles were measured in lambs from 20 ewes from each flock around the time of birth in an animal-house study, to define potential causes of the genetic difference in survival. In the intensive study, birth weight was similar for all groups; however, gestation length was slightly shorter in the SS+ lambs (P < 0.05 for SS+ v. R). All lambs had low plasma concentrations of the essential amino acids and glucose at birth, compared with after suckling. Plasma concentrations of glucose, non-esterified fatty acids (NEFA), and blood urea nitrogen (BUN) at birth differed between lambs from the flocks with the greatest difference in mortality (i.e. SS+ v. R); that is, SS+ lambs had higher concentrations of glucose (1.84 v. 1.23 mM; P < 0.01) and NEFA (1.52 v. 1.08 mM; P < 0.05), and lower concentrations of BUN (7.7 v. 9.7 mM; P < 0.01) at birth, and for the next 9 h. The semimembranosus and semitendinosus muscle of the SS+ lambs also had lower concentrations of ATP (7.4 v. 5.0 μmol/g, respectively) compared with lambs from the other flocks, immediately post-partum. Muscle phosphocreatinine was also slightly lower in the SS+ lambs. No differences between the genotypes were observed in reserves of glycogen, carcass fat, brown adipose tissue, or in neonatal thyroid hormones. In summary, sheep selected for high wool staple strength had lower lamb mortality than the other 2 flocks. This was accompanied by metabolic differences at birth that can be associated with greater metabolic maturity, rather than greater energy reserves

Carcass and meat characteristics of sheep with an additional growth hormone gene

Effects of high growth hormone (GH) activity on body composition and some aspects of meat quality were examined in sheep transgenic for an additional copy of the ovine GH gene, as a tool to explore the biological importance of the GH axis in sheep selected commercially for meat production. Carcasses of 16 GH and 25 control mixed-sex sheep aged 45 months, and 6 GH and 6 control ewes aged 20 months, were measured. The dressing percentage was lower in the GH sheep (P < 0.001). The GH sheep had similar muscle mass to controls, but the weight of their fat depots was reduced (P < 0.001) to approximately 40% of controls, whereas limb-bone mass was 43% greater (P < 0.001) than controls. Fore and hind limbs were equally affected. Skin and most internal organs were heavier, particularly the pancreas, kidney, alimentary canal, and the liver. The concentration of intramuscular fat in the GH sheep was only 27% that of controls (P < 0.001), whereas the average pH of muscle 24 h after slaughter and the melting point of subcutaneous fat were both increased (P < 0.05). Similar changes in organ weights and body composition have been observed in sheep selectively bred to enhance lamb growth rate or to decrease fatness, suggesting that relative GH activity contributed to the outcomes of those experiments. This study indicates the importance of a multi-trait breeding objective to ensure that mechanisms associated with GH do not impair meat quality

Relationships among puberty, muscle and fat, and liveweight gain during mating in young female sheep

Contents: Greater depths of muscle are associated with better reproductive performance in ewe lambs, but, in adult ewes, reproductive performance also seems to vary with liveweight gain during the mating period. Therefore, in a large field study with Merino ewe lambs, we tested whether the relationships among eye muscle depth (EMD), fat depth (FAT) and reproductive performance depend on liveweight gain during the mating period. We selected lambs with a wide range in phenotypic values for depths of eye muscle (EMD) and fat (FAT) and assigned them to dietary treatments designed to achieve low (LOW, n = 244) or high (HIGH, n = 237) rates of liveweight gain during a 28-day mating period. The LOW treatment maintained live weight, whereas the HIGH treatment gained 179 ± 3.8 g/day (p < 0.001). From those ewe lambs that attained puberty, first oestrus was detected at live weight 37.8 ± 0.2 kg and age 232 days. The proportion of ewes that attained puberty increased with EMD (p < 0.01). Ewes from the HIGH treatment were more fertile (pregnant ewes per 100 ewes exposed to rams) and had a higher reproductive rate (foetuses in utero per 100 ewes exposed to rams; p < 0.001) than those from the LOW treatment. Fertility and reproductive rate were positively correlated with weight gain during mating as well as live weight at the start of mating, FAT and EMD (p < 0.05 to <0.001). We conclude that faster growth, due to either extra nutrition during mating or higher phenotypic potential for fat and muscle, will increase reproductive performance in ewe lambs mated at 8 months of age

Liveweight loss in adult ewes is affected by their sires breeding values for fat and muscle

Ewes that lose more weight at times of nutritional pressure may decrease farm profitability through reduced production but also through reduced stocking rates, increased supplementary feeding costs and labour. Liveweight profiles were derived from the splined liveweight data of adult ewes from the Sheep CRC Information Nucleus Flock and liveweight loss was analysed. This paper reports on the response of liveweight loss to sire breeding values for fat and muscle in two contrasting environments. Overall liveweight loss was affected by significant differences between site, sire breed, ewe age, and previous and current reproductive performance. Sire breeding values for fat were significant, and interacted with site. There was a reduction in liveweight loss as sire breeding values for fat increased at Katanning in WA but an increase in liveweight loss at Kirby in NSW. Sire breeding values for muscle were also significant and different for each site, with the effects being opposite to fat at each site. These results suggest that selection against fat or selection for increased muscling may compromise the ability of ewes to maintain weight during summer and autumn in dry Mediterranean climates, however this may not be applicable for all environments

Relationships among body composition, circulating concentrations of leptin and follistatin, and the onset of puberty and fertility in young female sheep

The onset of puberty depends on the attainment of critical body mass, so should also be affected by increases in the rate of accumulation of muscle and adipose tissue. Adipose tissue and reproduction are linked by leptin. For muscle, a link has not yet been identified, although one possibility is follistatin. We assessed the relationships among circulating concentrations of follistatin and leptin and the rates of growth and accumulation of muscle and fat during pubertal development in female sheep. We used 326 animals with known phenotypic values for live weight (LW), depths of eye muscle (EMD) and fat (FAT), and known breeding values at post-weaning age for body mass (PWT) and depths of eye muscle (PEMD) and fat (PFAT). Leptin concentration was positively correlated with values for EMD, PEMD, FAT, PFAT, LW and PWT (P < 0.001), whereas follistatin concentration was negatively correlated with values for EMD and PWT (P < 0.001), and PEMD (P < 0.01) and FAT (P < 0.05). Leptin concentration was negatively related to age and positively related to live weight at first oestrus and the proportion of females that attained puberty (P ≤ 0.05), and to fertility and reproductive rate (P < 0.01). Follistatin concentration was negatively related to live weight at first oestrus and to fertility (P < 0.01) and reproductive rate (P < 0.05). There were positive correlations (P < 0.001) between muscle accumulation and leptin concentration, and between muscle accumulation and reproductive performance. We conclude that leptin and follistatin are probably both involved in effects of accelerated accumulation of muscle and adipose tissues on the onset of puberty