Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.     

The value of sea urchin,Lytechinus variegatus,egesta consumed by shrimp,Litopenaeus vannamei

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.     

Radioisotope and stable isotope ratios (Δ14C, δ15N) suggest larval lamprey growth is dependent on both fresh and aged organic matter in streams

Lampreys have a complex life cycle which includes a multi‐year infaunal larval stage (ammocoete). Gut content analysis has generally identified detritus (i.e., unidentifiable organic matter) as the major dietary component to ammocoetes, though algae can also be important. However, gut content preserves only a snapshot of the animal's diet and does not reflect assimilated material. In order to better characterise the nutritional sources supporting ammocoete growth, we analysed ammocoete body tissue and potential dietary sources at two streams using natural Δ¹⁴C and δ¹⁵N to estimate time‐integrated nutritional support. Bayesian isotope mixing models revealed differences in the importance of sources supporting ammocoetes between sites. Ammocoetes from a stream in a mixed land usage area (~50% agriculture, ~40% forest and ~10% developed) were primarily supported (mean: ~50%) by fresh terrestrial organic matter but were also supported by substantial contributions (mean: ~30%) by aged organic matter (AOM) and autochthonous material (algae; mean ~20%). In a predominantly forested (~90%) headwater stream, different modelling scenarios (uninformed or informed priors) suggested that algal support of ammocoete nutrition ranged from 7% to 45%. However, the model relying on informed priors developed from gut content analysis produced the low estimates, suggesting these were more reliable. When algae were a minor component of the nutrition at the forested site, ammocoetes were highly dependent on AOM (83 ± 26%; mean ± SD). Based on these findings, ammocoete growth and development are predicted to be strongly influenced by both land use and the availability of allochthonous and autochthonous materials of varying ages within streams.     

鄂尔多斯细羊毛生产经营分析及发展对策

鄂尔多斯细羊毛主要产自内蒙古自治区鄂尔多斯市乌审旗，羊毛综合品质堪比澳毛。近年来，在各级政府的大力支持下，当地相关部门积极探索，摸索出了一条有效的细羊毛生产经营之路，细羊毛价格连年攀升，当地农牧民实现稳步增收。为了进一步推进该地区细羊毛供给侧结构性改革，建议该地区进一步加强鄂尔多斯细毛羊品种改良，做好羊毛直销的组织工作，全面推行羊毛现代化管理技术，推行羊毛公正检验制度方面的生产经营模式。     

Three SNPs within exons of INHA and ACVR2B genes are significantly associated with litter size in Dazu black goats

The aim of this study was to analyse the association between single-nucleotide polymorphisms within INHA and ACVR2B and litter size in Dazu black goats. In total, twenty-two SNPs were genotyped in 190 individuals by SNaPshot and resequencing. The results showed that three SNPs (SNP_1, SNP_12 and SNP_13 in this study) were detected to have significant additive genetic effect on the recorded goat litter size (p < .05). The SNP_1 (NC_030809.1), a non-synonymous substitution of G for T at chr2-g. 28314990 in the exon 2 of INHA gene (NM_001285606.1), resulted in homozygote 2 (HOM2) contributed 0.25 and heterozygote (HET) contributed 0.12 larger litter than homozygote 1 (HOM1). Meanwhile, SNP_12 (Chr22-g. 11721225 A > T) and SNP_13 (Chr22-g. 11721227 A > C) (NC_030829.1) simultaneously mutated at the first and third position of a triplet AAA (lysine, K) in the exon 4 of ACVR2B gene (XM_018066623.1) had estimated genetic effects of HOM1 (0.00) and HOM2 (0.03) larger than HET (−0.12). In conclusion, one SNPs (chr2-g. 28314990 T > G) within the exon 2 of INHA and two SNPs (Chr22-g. 11721225 A > T and Chr22-g. 11721227 A > C) i n the exon 4 of ACVR2B gene were highly recommended as candidate markers of litter size in Dazu black goats. A large-scale association study to assess the impact of these variants on litter size is still necessary.     

Embodied Resources in Fish and Shrimp Feeds

Global averages were obtained for amounts of energy, land, water, wildfish, nitrogen, and phosphorus embodied in aquaculture feed ingredients. These data allowed amounts of these embodied resources to be calculated for typical feed formulations for channel catfish, Ictalurus punctatus; hybrid catfish, I. punctatus♀ × I. furcatus♂; Vietnamese catfish, Pangasius spp.; Atlantic salmon, Salmo salar; rainbow trout, Oncorhynchus mykiss; tilapia, Oreochromis spp.; whiteleg shrimp, Litopenaeus vannamei; and black tiger shrimp, Penaeus monodon. Embodied resource use per m.t. of feed varied among species: energy, 4.90–12.48 GJ/m.t.; land, 0.082–0.312 ha/m.t.; water, 502–1227 m³/m.t.; wildfish, 0–2880 kg/m.t.; nitrogen, 3.08–8.63 kg/m.t.; phosphorus, 1.16–5.62 kg/m.t. These calculations did not account for variations in site‐specific factors related to embodied resources and feed composition and use. But they suggest that reducing feed conversion ratio (FCR) by 0.1 unit for the seven species (species groups) could potentially reduce feed use by around 1.1 million tonne (Mt) while conserving 9.8 million GJ of energy, 270,000 ha of agricultural land, 1.4 billion m³ of freshwater, and 1.24 Mt of wildfish. Reduction of the FCR is a powerful means of lessening farm‐level production costs and negative impacts of feed production and use.     

典型山地草甸草原主要牧草生长发育情况分析

对天山北坡中山带典型山地草甸草原4种具有代表性的天然牧草——老芒麦（Elymus sibiricus）、黄（Astragalus membranaceus）、老鹳草（Geranium wilfordii）、千叶蓍（Achillea millefolium）的生长发育情况进行了研究。结果表明，4种牧草的高度变化趋势表现为“慢-快-慢”的植物基本生长规律；老芒麦、千叶蓍、老鹳草的生长速率在返青期到分蘖期时较快，而黄芪的生长速率则在返青后就较快，分蘖期后4种牧草的生长速率开始变慢；盖度和产量的最大值出现在6月和7月。     

植物乳杆菌野生质粒分析及其提取方法的优化

乳酸菌质粒提取研究具有很长的历史。目前已有多个有效的乳酸菌质粒提取方法被报道，其中多数以乳酸球菌为研究对象，而植物乳杆菌质粒提取有效方法报道较少。该研究以植物乳杆菌为研究对象，通过对比分析并优化已报道的乳酸菌质粒提取方法，得到了高效且适于平台期植物乳杆菌野生质粒的提取方法。通过该方法进一步分析了植物乳杆菌野生质粒数和高拷贝质粒，为后续构建植物乳杆菌表达系统所需供体质粒和受体菌株提供了重要依据。     

Soil protection for a sustainable future: options for a soil monitoring network for Ireland

The increased recognition of the importance of soil is reflected in the UN Post‐2015 Development Agenda with sustainable development goals that directly and indirectly relate to soil quality and protection. Despite a lack of legally binding legislation for soil protection, the European Commission remains committed to the objective of soil protection. However, the achievement of a legally binding framework for soil protection relies on the implementation of a soil monitoring network (SMN) that can detect changes to soil quality over time. As beneficiaries do not pay for the provision of soil information, the options for soil monitoring are limited. The use of existing data sets should be considered first. Using Ireland as an example, this research explored the opportunities for a SMN for Ireland considering three existing national data sets. The options for a SMN are considered in terms of their spatial and stratified distribution, the parameters to be measured and an economic analysis of the options proposed. This research finds that for Ireland, either a 10 or a 16 km² grid interval stratified by land use and drainage class offers the best potential in relation to the spatial distribution of existing data sets to reflect local data at a national level. With existing data, the stratified SIS data using the 16 km² grid offers the best value for money, with baseline costs for analysis, excluding field costs, of between €706 481 and €2.8 million. Acknowledging the impossibility of measuring all parameters with ideal frequency, this study proposes a two‐tier system for optimized monitoring frequency. Parameters must anticipate future policy requirements. Finally, the implementation of a SMN must be accompanied by standardized methods, defined thresholds and action mandates to maintain soil quality within allowable limits.     

Factors affecting skim milk progesterone assay results.

Five studies were performed to determine factors affecting progesterone concentration in skim milk. Results of the first study indicated that progesterone concentration was higher in skim milk of samples kept 16 hours in an ice bath (0 C) than of those left at room temperature (21 C). In the second study, this temperature effect was found to be reversible, with skim milk progesterone concentration increasing when whole milk samples were cooled prior to centrifugation. In the third study, [3H]-labeled progesterone was used to determine the relationship between fat content of foremilk (the first milk obtained from the teats), midmilk (milk obtained midway through milking), and strippings (milk obtained immediately after milking machines have been removed) samples and temperature (4 C and 21 C) on the percentage of progesterone in the skim milk fraction. The relationship between percentage of butterfat and percentage of progesterone in skim milk was linear when the log of these variables was used for calculations. In the fourth study, assayable progesterone in the skim milk fraction of foremilk, midmilk, and strippings was affected by temperature. In the fifth study, a multiple-regression procedure was used to determine the amount of variation in percentage of radioactive progesterone in the skim milk fraction. Independent variables (whole milk butterfat and temperature of incubation [1, 3, 13, 22, 37, and 50 C]) and the natural log of each variable, were entered into a stepwise multiple-regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)