评估调质时间和温度对猪颗粒饲料淀粉糊化度和维生素沉积的影响

本论文研究了饲料加工的两个关键参数(调质温度和时间)对育肥猪颗粒饲料淀粉糊化度和维生素沉积的影响。日粮配方为含30%干酒糟及其可溶物的玉米-豆粕型基础日粮。整个试验中配方保持不变。本试验采用2×3双因子设计,调质温度分别为77℃和88℃,调质时间分别15秒、30秒和60秒。此外,本试验还设置一个对照组,对照组饲料不采用调质制粒工艺,而是采用粉料饲喂。因此,本试验共有7个处理组。采集调质后制粒前(热干粉)、制粒后冷却前(热制粒)、以及制粒冷却后(冷制粒)的样品,并分析这三种样品的总淀粉率、淀粉糊化     

Factors influencing the occurrence of fall armyworm parasitoids in Zambia

Journal of Pest Science - Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and...     

Changes in the fish species composition of all Austrian lakes >50 ha during the last 150 years

Abstract  The fish communities of all Austrian natural lakes ( n  = 43) larger than 50 ha in surface area were assessed and the historical fish communities in c . 1850 were reconstructed. During the last 150 years, the fish communities of Austrian lakes have altered: in 49% of lakes at least one indigenous fish species, usually sensitive or small-bodied taxa, is now missing. Conversely, in all but one of the 43 lakes the number of fish species has increased. In particular, certain fish species of interest to angling and commercial fisheries now occur in more lakes. Generalised linear models were used to identify variables that would explain the loss of fish species using categories of lake use (ranking score). The category human population density around the lakes seemed to be one of the main causes for the loss of fish species.     

The antimicrobial activity of honey against common equine wound bacterial isolates

Delayed healing associated with distal limb wounds is a particular problem in equine clinical practice. Recent studies in human beings and other species have demonstrated the beneficial wound healing properties of honey, and medical grade honey dressings are available commercially in equine practice. Equine clinicians are reported to source other non-medical grade honeys for the same purpose. This study aimed to assess the antimicrobial activity of a number of honey types against common equine wound bacterial pathogens. Twenty-nine honey products were sourced, including gamma-irradiated and non-irradiated commercial medical grade honeys, supermarket honeys, and honeys from local beekeepers. To exclude contaminated honeys from the project, all honeys were cultured aerobically for evidence of bacterial contamination. Aerobic bacteria or fungi were recovered from 18 products. The antimicrobial activity of the remaining 11 products was assessed against 10 wound bacteria, recovered from the wounds of horses, including methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa. Eight products were effective against all 10 bacterial isolates at concentrations varying from <2% to 16% (v/v). Overall, the Scottish Heather Honey was the best performing product, and inhibited the growth of all 10 bacterial isolates at concentrations ranging from <2% to 6% (v/v).Although Manuka has been the most studied honey to date, other sources may have valuable antimicrobial properties. Since some honeys were found to be contaminated with aerobic bacteria or fungi, non-sterile honeys may not be suitable for wound treatment. Further assessment of gamma-irradiated honeys from the best performing honeys would be useful.     

Methods of assessing extinction risk in marine fishes

The decline and disappearance of species from large parts of their former geographical range has become an important issue in fisheries ecology. There is a need to identify which species are at risk of extinction. The available approaches have been subject to considerable debate – particularly when applied to commercially exploited species. Here we have compiled methods that have been used or may be used for assessing threat status of marine organisms. We organize the methods according to the availability of data on the natural history, ecology and population biology of species. There are three general approaches to inferring or assessing extinction risk: (i) correlative approaches based on knowledge of life histories and ecology; (ii) time‐series approaches that examine changes in abundance; and (iii) demographic approaches based on age‐ or stage‐based schedules of vital rates and fisheries reference points. Many methods are well suited to species that are highly catchable and/or have relatively low productivity, but theory is less well developed for assessing extinction risk in species exhibiting narrow geographical distributions or ecological specialization. There is considerable variation in both definitions of extinction risk and the precision and defensibility of the available risk assessment methods, so we suggest a two‐tiered approach for defining and assessing extinction risk. First, simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species. Second, the populations and species identified as vulnerable by this process can then be subject to more detailed and rigorous population analysis explicitly considering sources of error and uncertainty.     

Enigmatic hotspot of crayfish diversity at risk: Invasive potential of non‐indigenous crayfish if introduced to New Guinea

1. The large island of New Guinea has a rich indigenous astacofauna represented by numerous parastacids from the genus Cherax. The western half of the island is part of Indonesian territory.
2. Indonesia is known to be the main exporter of ornamental crayfish globally, and certain New Guinean species are exploited as ornamentals within the international pet trade. Moreover, one non‐indigenous species has been previously recorded being cultured in Java, Indonesia. This species, the North American Procambarus clarkii, is a vector of crayfish plague, the disease that is lethal to most parastacids. This population has already tested positive for the disease.
3. As the transport of non‐indigenous crayfish within the Indonesian territory is not restricted, their introduction to New Guinea can be expected. The Indonesian market was therefore surveyed for ornamental crayfish and their environmental suitability evaluated, as represented by temperature during the drought and rainy seasons in New Guinea.
4. Four North American and one Australian species were found advertised for sale. One of them, P. clarkii, was assessed as the most damaging species, followed by other North American species. A total ban on the culture and transport of the highest risk crayfish species in Indonesia and Papua New Guinea is recommended.

     

Dysentery caused by Escherichia coli (S102-9) in calves: natural and experimental disease

A dysentery syndrome was recognized among the Institute's calves at 18 to 21 days of age. It was reproduced experimentally in gnotobiotic calves with an atypical Escherichia coli (S102-9) isolated from the affected calves. In both natural and experimental disease the calves passed copious bright red blood in the feces and developed diarrhea. Walls of the colon and rectum were thickened, and the mucosa was reddened and covered by an exudate that contained mucus and blood clots. Bacteria were seen closely adherent to the luminal surfaces of enterocytes, often in cup-shaped depressions or on cytoplasmic pedestals. Microvilli were distorted, disorientated or absent. There was exfoliation of infected enterocytes and a mild acute inflammation of the underlying lamina. In two of five calves with natural disease, the adherent bacteria did not stain by the immunoperoxidase method with antisera raised against E. coli (S102-9). This indicated that there was possibly more than one bacterial cause of the syndrome. Lesions in experimentally infected calves were indistinguishable from those produced by some E. coli which are enteropathogenic for man, rabbits, and pigs.     

Viral pathogenesis of a nephrotropic infectious bronchitis virus isolated from commercial pullets.

Infectious bronchitis was diagnosed in 3-to-4-week-old pullets from an outbreak in a commercial flock in California. The disease was characterized by head swelling, watery discharge from the eyes and nostrils, and urates in kidneys. Mortality ranged from 1.8% to 12.5% per week. The isolation of a coronavirus from a suspension of pooled kidneys from clinically ill chickens at the fifth passage in 10-day-old chicken embryos, gross and histologic renal lesions, and seroconversion by enzyme-linked immunosorbent assay in inoculated birds suggested that the virus isolated was a nephrotrophic strain of infectious bronchitis virus (IBV). The virus isolate was found to be a previously unrecognized serotype, based on virus neutralization tests performed in embryonated chicken eggs. Nephropathogenicity of the IBV isolate was confirmed by inoculation of the viral isolate into specific-pathogen-free chicks and demonstration of renal lesions. The isolation of nephrotropic strains of IBV has not been reported previously from poultry in California.     

Age and growth of yellow eel, Anguilla anguilla (L.), determined by two different methods

Abstract– Ageing and calculation of growth rate of eels has always been controversial, and remarkably little validation has been reported. This article describes the growth of yellow eels from three lakes in the Burrishoole system, Ireland, as determined by back-calculation from otoliths prepared by burning and cracking. Eels captured by fyke net ranged in length from 25.0 cm to 98.5 cm and the ages ranged from 6 to 49 years. Back-calculated growth was slow, with mean annual increments of 2.08 cm, 1.40 cm and 1.97 cm for the three lakes. Yellow eels captured in the Burrishoole system in 1987 and 1988 were marked by Pan Jet inoculated alcian blue dye and released back into the three lakes. Recaptures made over the following three years yielded considerable growth data. Mean annual growth rates recorded were 2.30 cm, 1.07 cm and 0.97 cm. These data compare favorably with the calculated growth rates, thereby validating the otolith analysis for the eels in the Burrishoole system.     

Carbon Isotope Discrimination, Leaf Ash Content and Grain Yield in Bread and Durum Wheat Grown under Full-Irrigated Conditions

Integrative physiological criteria, such as carbon isotope discrimination (Δ) and (mineral) ash content (m_a) have been found to be very useful, under drought conditions, to elucidate the association between yield gains and variation of photosynthesis‐related traits and orientate future breeding efforts. Information on this association is scarce under irrigated conditions. The relationships between Δ, m_a and yield were studied in bread wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum L. var. durum) under optimal (drip) irrigation in the arid conditions of north‐west Mexico. Carbon isotope discrimination was analysed on leaves at booting stage and anthesis and on grain at maturity, whereas ash content was measured on the flag leaf at anthesis and maturity. At anthesis, there were differences between bread and durum wheat during grain filling for Δ, but not for m_a. No relationship was found between grain yield and Δ. Leaf ash content at anthesis and maturity showed a broad variability within each species and were associated with grain yield. These results suggest that ash content in leaves could be also used as predictive criteria for yield not only under drought, but also under irrigated conditions, particularly when evaporative demand is high.