Long-term application of animal slurries to grassland alters soil cation balance

Abstract. Soil samples from a 32-year grassland field experiment were taken from 0–5, 5–10, and 10–15 cm soil depths in February 2002. Plots received annual treatments of unamended control, mineral fertilizer, three rates of pig slurry and three rates of cow slurry, each with six replicates. Samples were analysed for cation exchange capacity (CEC), exchangeable cations (Na⁺, K⁺, Ca²⁺, Mg²⁺), pH and Olsen P. Exchangeable sodium percentage (ESP) was calculated as a sodicity indicator. Mean ESP was generally greater for slurry treatments than the control, with a trend of increasing ESP with application rate. This was particularly marked for cow slurry. At 0–5 cm depth ESP increased from 1.18 in the control to 1.75 at the highest rate of pig slurry and 5.60 at the highest rate of cow slurry. Similar trends were shown for CEC, exchangeable Na⁺, K⁺ and Mg²⁺, Ca²⁺ and Olsen P. The build-up of soil P due to slurry applications, together with this combination of physical and chemical factors, may increase the risk of P loss to surface waters, particularly from soils receiving high rates of cow slurry.     

The Role of Hepatic Ultrasonography in Small Animal Medicine: From the Identification of the Lesions to Diagnosis

Veterinary Research Communications -     

Spatial distribution of Aspergillus flavus and its toxigenic strains on commercial cottonseed from south Texas and its relationship to aflatoxin contamination

The structure of Aspergillus flavus communities associated with south Texas cottonseed was determined by analysing samples from 178 truckloads of commercial cottonseed from 35 gins, extending from Fort Bend County in the north to the Rio Grande Valley in the south, from September 1999 to October 2001. The number of colony-forming units (CFU) of A. flavus on the cottonseed, and the percentage of S strain (%S) were both correlated with aflatoxin contamination of cottonseed. The number of CFU differed between both regions and seasons, while %S differed only between regions. Comparison of maps of CFU and %S revealed that CFU shows a higher variation across years, while %S shows higher spatial variation. The Rio Grande Valley had significantly lower CFU and %S strain than the Coastal Bend and Upper Coast regions. Cottonseed produced in 1999 had significantly more A. flavus than that produced in either 2000 or 2001. Identification of factors dictating geographical variation in S-strain incidence may provide insights that will lead to improved aflatoxin management.     

中国平背树螽属两新种(直翅目:螽斯科:树螽亚科)

描述了平背树螽属2新种,定名为双刺平背树螽(Isopsera bicuspidota Yang etKang)和广西平背树螽(I.guangziensis Yang et Kang)。     

Effectiveness of four methods for tagging juveniles of farm-reared gilthead sea bream, Sparus aurata, L.

This study tested different tags for each size of farm-reared gilthead sea bream, Sparus aurata L. juveniles, used in enhancement programmes. The following tags were tested: dye mark, fingerling tag, opercular tag, anchor tag A (filament diameter of 1.20 mm) and anchor tag B (0.85 mm). Tag/mark retention, wounds produced by the tag, ease of application, ease of detection and cost were examined. Epidermal dye marks had poor retention and detection rates. Of the tags tested, retention was greater for the anchor tag A (80–100%) after 7 months; anchor tag B showed a retention rate of only 20% after 3 months. The fingerling tag had a retention rate of 27.5% after 12 months. The opercular tag had a retention rate of 44% after 20 days but fractured the opercular bone in many cases. Tag incisions and wounds persisted in some fish for the duration of the experiment.     

Nuclear transfer in loach (Paramisgurnus dabryanus Sauvage) by cell-to-cell electrofusion

To study nuclear transfer in the loach (Paramisgurnus dabryanus Sauvage), blastula and gastrula cells were fused with UV-inactivated oocytes by cell-to-cell electrofusion. To facilitate nuclear transfer, blastula and gastrula cells were cultured or incubated at 4 °C in different solutions. TC-199 medium supplemented with 20% calf serum was the best culture solution, and effectively retained the totipotence of blastula or gastrula cells for up to 10 days. It was found that gastrula cells incubated at 4 °C had the same totipotence as blastula cells. The optimal UV dosage for inactivation of the oocyte chromatin was 180–240 mJ cm⁻². Electrofusion was carried out in a cone-shaped fusion chamber, which permitted the recipient oocyte and the donor blastula cell to contact one another. The electrofusion procedure resulted in a 10% success rate of normal-appearing fish. Genetic analysis indicated that the nuclear material originated from the donor cell (blastomere) and the oocyte pronucleus did not take part in development.     

Effects of Stocking Sac-Fry and Hatchery-Fed Fry on Production of Fingerling Channel Catfish Ictalurus punctatus

Abstract.— Channel catfish Ictalurus punctatus fry are typically held under hatchery conditions for 7 to 14 d after hatching to allow feeding and growth before they are stocked into nursery ponds to produce fingerling catfish. In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as "sac-fry." Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac-fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2-, 7-, and 14-d post-hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac-fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early-age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac-fry can be recommended to the catfish industry.     

Genetic diversity estimates in Cicer using AFLP analysis

Amplified fragment length polymorphism (AFLP) analysis was used to evaluate the genetic variation among cultivated chickpea and wild Cicer relatives. In total, 214 marker loci were assessed, of which 211 were polymorphic (98.6%) across the 95 accessions that represented 17 species of Cicer. The genetic variation within a species was highest in C. pinnatifidum followed by C. reticulatum and lowest in C. macracanthum. Three main species groups were identified by UPGMA clustering using Nei's pair‐wise distance calculations. Group I included the cultivated species C. arietinum, C. reticulatum and C. echinospermum. Within this group, C. reticulatum accessions were clustered closest to the C. arietinum cultivars ‘Lasseter’, ‘Kaniva’ and ‘Bumper’, supporting the hypothesis that C. reticulatum is the most probable progenitor of the cultivated species. Cicer bijugum, C. judaicum and C. pinnatifidum were clustered together creating group II. Group III contained all nine perennial species assessed and two annual species C. yamashitae and C. cuneatum. The genetic distance detected between group I and group III (0.13) was equivalent to the genetic distance detected between group I and group II (the primary and annual tertiary species, respectively; 0.14). This indicated that the perennial tertiary species may be as valuable for increasing variation to incorporate novel germplasm in the cultigen as the annual tertiary species.     

Comparative evaluation of the effect of two maternal diets on fatty acids, vitamin E and carotenoids in the chick embryo.

1. The fatty acid profile of egg yolk and vitamin E and carotenoid accumulation in the egg yolk and embryonic tissues were investigated in relation to the maternal diet. 2. Two hundred fertile eggs (Ross 308 Broiler Breeder), obtained from hens fed on a maize-based (M-diet) or a wheat-based diet (W-diet), were incubated using standard conditions. 3. The egg yolk and embryo tissues (residual yolk, yolk sac membrane, liver, kidney, lung, muscles, adipose tissue and plasma) were collected on d 18 of incubation and on d 21 (newly-hatched chicks) and analysed for fatty acids, vitamin E and carotenoids. 4. The diets did not differ in terms of fatty acid or alpha-tocopherol concentrations. The concentration of carotenoids in the M-diet was 11.8 mg/kg and in the W-diet was 5.6 mg/kg with lutein and zeaxanthin being major carotenoids. 5. Eggs from the M-group contained higher (P<0.01) concentrations of beta+gamma-tocopherols, total carotenoids, lutein and zeaxanthin. Chickens hatched from those eggs were characterised by the increased concentrations of total carotenoids and zeaxanthin in all the tissues studied. The concentration of beta+gamma-tocopherol was enhanced only in the liver and yolk sac membrane. 6. It is concluded that the maternal diet plays an important role in antioxidant systems formation during chick embryonic development; the M-diet can increase the antioxidant potential of the egg yolk and embryonic tissues compared to the antioxidant potential provided by parent birds fed the W-diet.