A genome-wide association study of meat and carcass traits in Australian cattle

Chromosomal regions containing DNA variation affecting the traits intramuscular fat percentage (IMF), meat tenderness measured as peak force to shear the LM (LLPF), and rump fat measured at the sacro-iliac crest in the chiller (CHILLP8) were identified using a set of 53,798 SNP genotyped on 940 taurine and indicine cattle sampled from a large progeny test experiment. Of these SNP, 87, 64, and 63 were significantly (P < 0.001) associated with the traits IMF, LLPF, and CHILLP8, respectively. A second, nonoverlapping sample of 1,338 taurine and indicine cattle from the same large progeny test experiment genotyped for 335 SNP, including as a positive control the calpastatin (CAST) c.2832A > G SNP, was used to confirm these locations. In total, 37 SNP were significantly (P < 0.05) associated with the same trait and with the same favorable homozygote in both data sets, representing 27 chromosomal regions. For the trait IMF, the effect of SNP in the confirmation data set was predicted from the discovery set by multiplying the estimated allele effect of each SNP in the discovery set by the number of copies of the reference allele of each SNP in the confirmation set. These weighted effects were then summed over all SNP to generate a molecular breeding value (MBV) for each animal in the confirmation data set. Using a bivariate analysis of MBV and IMF phenotypes of animals in the confirmation set, a panel of 14 SNP explained 5.6 and 15.6% of the phenotypic and genetic variance of IMF, respectively, in the confirmation data set. The amount of variation did not increase as more SNP were added to the MBV and instead decreased to 1.2 and 3.8% of the phenotypic and genetic variance of IMF, respectively, when 329 SNP were included in the analysis.     

Effects of Environmental Stress on Forest Crown Condition in Europe. Part IV: Statistical Analysis of Relationships

Site-specific estimates for various environmentalstress factors were related with measured crowncondition data at a systematic 16 ×: 16 km² gridover Europe, according to previously statedhypotheses, using a multiple regression approach,including interactions, and lagged effects of stressfactors. Methodological differences among countriesaccounted for >30% of the variation in defoliation.Nevertheless, crown condition was found to varynaturally with tree age, altitude, drought stress and,most likely, also pathogenic fungi and insects.Significant impacts of air pollution (specificallyozone but also NO_x, SO_x and acid deposition)were found at regional levels in parts of centralEurope, particularly for deciduous species. Impactsseemed less significant for conifers, especially forspruce, but this might be affected by confoundingeffects or strong correlations between (a harsh)climate and (low) atmospheric deposition in the areawhere spruce predominates. National studies indicatethat ozone and acid deposition can have a significanteffect on the defoliation of spruce as well. Weconclude that while forest condition varies naturally,continued emissions will contribute further to forestdecline in the long term.     

含盐饲用酶复合物稳定性研究

随着生物技术的发展 ,越来越多的酶能够廉价地进行工业化生产 ,并在饲料工业中广泛地应用。但是这些酶 (包括它们的复合物 )有一个重要弱点—容易失活 ,不仅在加工过程中的极端条件(如高温 ,p H偏高或偏低 )下容易失活 ,即使在常温下长期存放也容易失活。通常采用的减少酶失活的方法是使用各种不同的添加剂。如在酶溶液中加入各种金属盐 ,再通过冷冻干燥、喷雾干燥等方法获得干燥物。需要指出的是 ,在许多情况下必须使用酶的干燥物。尽管干燥对于提高酶的稳定性是一个有价值的手段 ,但干燥过程经常会引起酶活性的损失 ,而且最终产品 (干酶 …     

Phytoremediation: European and American trends successes, obstacles and needs

Phytoremediation is an emerging technology based on the use of green plants to remove, contain, inactivate or destroy harmful environmental pollutants. Recent developments in Europe and the USA show that the approach is somewhat different on both sides of the Atlantic. In Europe, phytoremediation has more basically been research driven and, based on the outcomes, applications have been envisaged. By contrast, the approach in the USA is more application and experience driven. In spite of a growing track record of commercial success, more demonstration projects are needed to prove that phytoremediation is effective in order to rigorously measure its underlying economics, and to expand its applications. More fundamental research is also required to better understand the complex interactions between pollutants, soil, plant roots and micro-organisms at the rhizosphere level, to increase the bioavailability of pollutants, to fully exploit the metabolic diversity of plants and, thus, to successfully implement this new green technology.     

Molecular genetic approaches for identifying the basis of variation in resistance to tick infestation in cattle

In recent years there has been renewed interest in the adaptation of cattle to challenging environments, largely driven by advances in genomic methods. The current interest in tick resistance is understandable given the major production and welfare implications of tick infestation in tropical and subtropical zones where around 70% of beef cattle are located. Heritability for tick burden in cattle has been shown to range about 0.30, which is sufficient to result in the success of some programs of selection for tick resistance in cattle. Gene-expression studies strongly indicate that both immune and non-immune mechanisms are associated with tick resistance in cattle. Recent quantitative-trait mapping studies have identified chromosome segments and single nucleotide polymorphisms associated with tick burden, but no causal variant has been identified so far. Most of the genetic markers identified for tick burden explain a relatively small proportion of the variance, which is typical of markers for quantitative traits. This leads to the conclusion that panels of multiple markers for tick resistance rather than a single marker will most likely be developed, possibly involving specific panels for zebu or taurine breeds, which could be used for future selection and breeding programs in cattle.     

评估土壤微量元素生物有效性测定方法

Trace element-contaminated soils (TECSs) are one of the consequences of the past industrial development worldwide.Excessive exposure to trace elements (TEs) represents a permanent threat to ecosystems and humans worldwide owing to the capacity of metal(loid)s to cross the cell membranes of living organisms and of human epithelia,and their interference with cell metabolism.Quantification of TE bioavailability in soils is complicated due to the polyphasic and reactive nature of soil constituents.To unravel critical factors controlling soil TE bioavailability and to quantify the ecological toxicity of TECSs,TEs are pivotal for evaluating excessive exposure or deficiencies and controlling the ecological risks.While current knowledge on TE bioavailability and related cumulative consequences is growing,the lack of an integrated use of this concept still hinders its utilization for a more holistic view of ecosystem vulnerability and risks for human health.Bioavailability is not generally included in models for decision making in the appraisal of TECS remediation options.In this review we describe the methods for determining the TE bioavailability and technological developments,gaps in current knowledge,and research needed to better understand how TE bioavailability can be controlled by sustainable TECS management altering key chemical properties,which would allow policy decisions for environmental protection and risk management.     

Production and processing studies on calpain-system gene markers for beef tenderness: consumer assessments of eating quality

We investigated the effects of calpain-system genetic markers on consumer beef quality ratings, including interactions of marker effects with hormonal growth promotant (HGP) use and tenderstretch hanging. Brahman cattle in New South Wales (NSW; n = 164) and Western Australia (WA; n = 141) were selected at weaning from commercial and research herds to achieve balance and divergence in calpastatin (CAST) and calpain 3 (CAPN3) gene marker status. Genotypes for μ-calpain (CAPN1-4751 and CAPN1-316) were also determined. Angus cattle (49 in NSW, 17 in WA) with favorable CAST and CAPN3 alleles, balanced for CAPN1-316 status, were also studied. Half the cattle at each site had HGP (Revalor-H, containing 200 mg trenbolone acetate and 20 mg 17β-estradiol) implants during grain finishing. One side of each carcass was suspended from the Achilles tendon (AT) and the other from the pelvis [tenderstretch (TS)]. Meat Standards Australia consumer panels scored 7-d aged striploin steaks from both AT and TS sides, and 7-d aged rump and oyster blade steaks from the AT side of each carcass. Two favorable CAST alleles increased tenderness ratings of AT-striploin, TS-striploin, rump, and oyster blade steaks by, respectively, 6.1, 4.2, 4.2, and 3.1 units, and overall liking by 4.7, 2.8, 2.9, 3.7 (all P < 0.04). Two favorable CAPN1-4751 alleles increased tenderness of AT-striploin, TS-striploin, and rump steaks by 6.5, 4.3, and 3.9 units, and overall liking by 5.6, 3.1, and 4.1 units. Two favorable CAPN3 alleles improved rump steaks by 3.7, 3.3, 3.7, and 3.5 units, for tenderness, juiciness, liking the flavor, and overall liking. There were no significant CAPN1-316 effects. The effect of HGP was greatest for the AT-striploin (reducing tenderness and overall liking by 8.2 units, P < 0.001), then TS-striploin (-5.6 for tenderness, -5.0 for overall liking, P < 0.001), and then rump (-4.4 for tenderness, -3.3 for overall liking, P < 0.007). Processing conditions differed considerably between NSW and WA. Rump steaks from NSW scored about 10 units greater than those from WA, but Angus and Brahman steaks from the same location with the same marker alleles had similar scores. In contrast, NSW Angus striploin steaks scored about 15 units greater for tenderness and overall liking (P < 0.001) than cattle with the same marker alleles at the other 3 location × breed combinations, which had generally similar scores. Therefore, calpain-system gene markers have beneficial effects on eating quality, consistent with our previous findings for objective meat quality.     

Genome-wide association studies for feedlot and growth traits in cattle

A genome wide-association study for production traits in cattle was carried out using genotype data from the 10K Affymetrix (Santa Clara, CA) and the 50K Illumina (San Diego, CA) SNP chips. The results for residual feed intake (RFI), BW, and hip height in 3 beef breed types (Bos indicus, Bos taurus, and B. indicus × B. taurus), and for stature in dairy cattle, are presented. The aims were to discover SNP associated with all traits studied, but especially RFI, and further to test the consistency of SNP effects across different cattle populations and breed types. The data were analyzed within data sets and within breed types by using a mixed model and fitting 1 SNP at a time. In each case, the number of significant SNP was more than expected by chance alone. A total of 75 SNP from the reference population with 50K chip data were significant (P < 0.001) for RFI, with a false discovery rate of 68%. These 75 SNP were mapped on 24 different BTA. Of the 75 SNP, the 9 most significant SNP were detected on BTA 3, 5, 7, and 8, with P ≤ 6.0 × 10(-5). In a population of Angus cattle divergently selected for high and low RFI and 10K chip data, 111 SNP were significantly (P < 0.001) associated with RFI, with a false discovery rate of 7%. Approximately 103 of these SNP were therefore likely to represent true positives. Because of the small number of SNP common to both the 10K and 50K SNP chips, only 27 SNP were significantly (P < 0.05) associated with RFI in the 2 populations. However, other chromosome regions were found that contained SNP significantly associated with RFI in both data sets, although no SNP within the region showed a consistent effect on RFI. The SNP effects were consistent between data sets only when estimated within the same breed type.