The effects of grit supplementation and feed type on steel-shot ingestion in mallards

Lead poisoning by shot-pellet ingestion is an important cause of death in waterfowl from wetlands that have high densities of lead-shot pellets and low availabilities of grit in their sediments. To evaluate grit supplementation when mixed with baited grain as a method of reducing shot ingestion in waterfowl, 24 mallards (Anas platyrhynchos) were kept in captivity to study the relationship between steel-shot, grit and grain ingestion in four experiments. Steel-shot ingestion was more related to seeking grit than to feeding on grain, and it did not differ between two types of grain offered (rice or sorghum). Grit ingestion increased with grit supplementation and shot ingestion was only slightly reduced. Calcareous grit used in the experiments had a shorter half-life (1.4 days) in the gizzard than values reported for siliceous grit (3.1 days).     

Comparative IFN-τ Secretion after Hatching by Bovine Blastocysts Derived Ex Vivo and Completely Produced In Vitro

The interferon-tau (IFN-tau) secretion levels after hatching by bovine blastocysts derived from in vitro maturated oocytes (Group A) and from in vivo (Group B) were investigated considering embryo quality. Only very homogeneous blastocysts of excellent or good quality were considered from day 7 of culture (Group A) and day 7 after artificial insemination with frozen-thawed from the same bull used for in vitro fertilization (Group B). All embryos were individually cultured into a 50 microl droplet of synthetic oviduct fluid medium with 10% fetal calf serum. After 24-h culture both Group A (n=44) and B (n=40) secreted <54 pm IFN-tau. After 48-, 72-, 96- and 120-h culture, Group A daily secreted 143 +/- 24 pm IFN-tau (n=19) vs 85 +/- 12 pm IFN-tau (n=21) for Group B (p < 0.01), 491 +/- 128 pm IFN-tau (n=29) vs 216 +/- 37 pm IFN-tau (n=23) (NS), 499 +/- 135 pm IFN-tau (n=26) vs 353 +/- 93 pm IFN-tau (n=21) (NS), 559 +/- 136 pm IFN-tau (n=22) vs 333 +/- 75 pm IFN-tau (n=20) (NS), respectively. Taken all together during 5 days, Group A produced per embryo 1690 +/- 290 pm IFN-tau (n=22) vs 982 +/- 182 pm IFN-tau (n=20) for Group B (p < 0.05). For all culture time there were sizable percentages of embryos that did not produce concentrations of IFN-tau above a certain cut-off level, and as such were not used to compute the means. In respect of the embryo quality whatever the groups after days 7-12 of culture, IFN-tau secretions were 1815 +/- 453 pm (n=10) for the embryos of excellent quality vs 1356 +/- 200 pm (n=28) for those of good quality (NS) and 360 +/- 188 pm (n=4) (p < 0.05) for embryos of fair quality. A positive relationship between IFN-tau production and in vitro development of quality I embryos was observed, whatever the embryos origins and, the embryos completely produced in vitro secreted more IFN-tau than the embryos produced in vivo.     

Successful Low Dose Insemination of Flow Cytometrically Sorted Ram Spermatozoa in Sheep

The fertility of ram spermatozoa that had undergone flow cytometric sorting (MoFlo SX) and cryopreservation was assessed after low-dose insemination of synchronized Merino ewes. Oestrus was synchronized with progestagen-impregnated pessaries, PMSG and GnRH treatment. Ewes (n = 360) were inseminated with 1 x 10(6), 5 x 10(6) or 15 x 10(6) motile sorted frozen-thawed (S(1), S(5), or S(15) respectively) or non-sorted frozen-thawed (C(1), C(5) or C(15) respectively) spermatozoa from three rams. An additional group of ewes were inseminated with 50 x 10(6) motile non-sorted frozen-thawed spermatozoa (C(50)) to provide a commercial dose control. The percentage of ewes lambing after insemination was similar for C(50) (24/38, 63.2%), C(15) (37/54, 68.5%), S(15) (38/57, 66.7%), S(5) (37/56, 66.1%) and S(1) (32/52, 61.5%) groups (p > 0.05), but lower for C(5) (19/48, 39.6%) and C(1) (19/55, 34.5%) treatments (p < 0.05). This study demonstrates sorted ram spermatozoa are equally fertile to non-sorted spermatozoa even when inseminated at 2% of the dose. Furthermore, at very low artificial insemination doses (1 or 5 million motile) the fertility of sorted ram spermatozoa is superior to non-sorted spermatozoa inseminated in equal numbers. These results have significance for the future commercialization of sex-preselection technology in sheep as a reduction in the minimum effective sperm number will allow a corresponding decrease in the associated cost per dose.     

夏秋用家蚕品种湖·滨×明·光的选育

采用杂交、回交、系统分离育种方法,育成了适合长江流域夏秋蚕饲养的家蚕新品种湖.滨×明.光。经实验室多年夏秋季饲养鉴定,新品种的虫蛹率与对照品种9.芙×7.湘相仿,主要经济性状均超过对照种,万蚕收茧量16.73 kg,万蚕茧层量3.947 kg,分别比对照种提高15.5%和28.4%;一粒茧丝长1153.5 m,解舒丝长932.5 m,分别比对照种增长210.5 m和166.5 m。该品种具有强健好养、产量高、茧丝质优良、适应性广等特点。     

Total nitrogen,carbon and phosphorus digestibility in gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) fed with conventional and organic commercial feeds: implications for particulate waste production

Organic fish farming is postulated as a more environmentally friendly activity than conventional activities. However, environmental sustainability as regards waste output has not been addressed. In this respect, the most important environmental problems associated with fish farming are those related with the discharge of particulate wastes. In this study, total nitrogen, carbon and phosphorus digestibility was estimated in a wide size range of gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) fed a commercially available conventional diet and an organic feed, as a previous step to assessing particulate waste output. Neither fish size nor feed nutrient content was seen to influence nutrient digestibility in either species. The organic diet provided higher carbon but lower nitrogen and phosphorus digestibility than conventional feed in both species. Simulations under real ongrowing conditions resulted in lower values for nitrogen and higher values for carbon particulate wastes when conventional feed was supplied to both species. Particulate phosphorus wastes were 2.6‐ to 3.4‐fold higher for fish fed the organic diet. Restrictions concerning NO the raw materials used for organic diet formulation and differences in nutrient bioavailability between the diets seemed to be the underlying reason for the differences found.     

Temperature and surface-ocean water balance of the mid-holocene tropical western pacific

Skeletal Sr/Ca and 18O/16O ratios in corals from the Great Barrier Reef, Australia, indicate that the tropical ocean surface approximately 5350 years ago was 1 degrees C warmer and enriched in 18O by 0.5 per mil relative to modern seawater. The results suggest that the temperature increase enhanced the evaporative enrichment of 18O in seawater. Transport of part of the additional atmospheric water vapor to extratropical latitudes may have sustained the 18O/16O anomaly. The reduced glacial-Holocene shift in seawater 18O/16O ratio produced by the mid-Holocene 18O enrichment may help to reconcile the different temperature histories for the last deglaciation given by coral Sr/Ca thermometry and foraminiferal oxygen-isotope records.     

A multi-trait multi-environment QTL mixed model with an application to drought and nitrogen stress trials in maize (Zea mays L.)

Despite QTL mapping being a routine procedure in plant breeding, approaches that fully exploit data from multi-trait multi-environment (MTME) trials are limited. Mixed models have been proposed both for multi-trait QTL analysis and multi-environment QTL analysis, but these approaches break down when the number of traits and environments increases. We present models for an efficient QTL analysis of MTME data with mixed models by reducing the dimensionality of the genetic variance–covariance matrix by structuring this matrix using direct products of relatively simple matrices representing variation in the trait and environmental dimension. In the context of MTME data, we address how to model QTL by environment interactions and the genetic basis of heterogeneity of variance and correlations between traits and environments. We illustrate our approach with an example including five traits across eight stress trials in CIMMYT maize. We detected 36 QTLs affecting yield, anthesis-silking interval, male flowering, ear number, and plant height in maize. Our approach does not require specialised software as it can be implemented in any statistical package with mixed model facilities.