Demand feeding and welfare in farmed fish     

Attia J  Millot S  Di-Poï C  Bégout ML  Noble C  Sanchez-Vazquez FJ  Terova G  Saroglia M  Damsgård B 《Fish physiology and biochemistry》2012,38(1):107-118

Following the development of demand-feeding systems, many experiments have been conducted to explore feeding motivation and feed intake in farmed fish. This work aims to review a selection of studies in the field, focusing on three key factors, related to demand feeding and fish welfare. Firstly, we outline how demand feeders should be considered when developing feed management strategies for improving welfare in production conditions. Secondly, via laboratory demand-feeding experiments, we show self-feeding activities depend not only on feeding motivation and social organisation, but also on individual learning capacity and risk-taking behaviour. Thirdly, we report encouraging results demonstrating that when presented with two or more self-feeders containing complementary foods, fish select a diet according to their specific nutritional requirements, suggesting that demand feeders could be used to improve welfare by allowing fish to meet their nutritional needs.  相似文献   

Census Report of the <Emphasis Type="BoldItalic">Potato Virus Y</Emphasis> (PVY) Population in Swiss Seed Potato Production in 2003 and 2008     

Stefania Rigotti  Carole Balmelli  Paul Gugerli 《Potato Research》2011,54(2):105-117

The status of the Potato virus Y (PVY) in Swiss seed potato production was investigated in the years 2003 and 2008 by analysing 385 leaf samples of field-grown, suspicious potato plants collected in four representative seed control fields. Serological investigations by ELISA showed that in c. 84% of the PVY-positive samples in both years, viruses belonging to the PVY^N group were found. All 124 serologically positive PVY samples collected in 2003 and a selection of 81 isolates of 2008 were further typified by molecular tests and by biological assays on tobacco and potato plants. These tests largely confirmed the predominance of the PVY^N group and, within this group, the prevalence of recombinant PVY^NTN, with 81.4% and 70.4% in 2003 and 2008, respectively. The percentage of PVY^N-Wilga (PVY^N-Wi) increased from c. 6% to 17% between the two years. PVY^O was detected only in 10.5% and 4.9% of all molecularly analysed samples in 2003 and 2008, respectively. The persistent predominance of recombinant PVY^NTN in Swiss seed potatoes indicates that this strain group is now widespread, representing a considerable threat to Swiss seed potato production.  相似文献   

Influence of nacre deposition rate on cultured pearl grade and colour in the black-lipped pearl oyster Pinctada margaritifera using farmed donor families     

Carole Blay  Manaarii Sham-Koua  Vincent Vonau  Roger Tetumu  Philippe Cabral  Chin-Long Ky 《Aquaculture International》2014,22(2):937-953

Cultured pearl nacre deposition rate in Pinctada margaritifera oysters was studied to examine its influence on Tahitian classification grade and colour and to further our understanding of using selected donor oysters produced in a hatchery system for the improvement of these traits. A large-scale grafting experiment using 150 farmed donor oysters was realised in Rangiroa atoll (French Polynesia). After 18 months of culture, 874 pearls were harvested and 7 pearls quality traits were recorded: (1) nacre deposition rate assessed by nacre thickness and weight, (2) classification grade, lustre and surface defects, and (3) colour assessed by pearl colour darkness level and visual colour categories. Nacre deposition rate significantly influence pearl grade, surface defects, darkness level and colour categories, but not the lustre. Grade A pearls had the thickest and heaviest nacre on average, compared with grade D pearls and rejects. In addition, pearls without any surface defect had thicker and heavier nacre. Pearls with low darkness were the thinnest and the lightest. Pearls of aubergine–peacock secondary colours were the thickest and the heaviest. These results highlight the importance of rapid nacre deposition rate for increasing the production of grade A pearls, with less surface defects and dominance of a black tone colour. Fast nacre deposition may, however, have a negative impact on other pearl quality traits, such as pearl lustre. This study demonstrates the importance of examining relationships between pearl quality traits in a way that provides solid information that can be directly used for breeding and genetic selection programmes.  相似文献   

Comparative study of plasma leptin concentration between solid ruminal and liquid abomasal feeding in weaned adult sheep     

Tomomi BAN‐TOKUDA  Carole DELAVAUD  Yves CHILLIARD  Tsutomu FUJIHARA 《Animal Science Journal》2010,81(6):648-656

This experiment was conducted to investigate the difference between ruminal (solid feed, SF) and abomasal (liquid feed, LF) feeding on the plasma leptin concentration in sheep. The experiment consisted of 2 weeks to adapt the animals to SF, 4 weeks of feeding on SF, 2 weeks adaptation to LF, 8 weeks of feeding on LF, 2 weeks of adaptation to SF, and 4 weeks of feeding on SF. The LF directory flowed into the abomasums of sheep by bottle feeding. Plasma leptin concentration before morning feeding was almost constant in the SF periods, whereas it showed between‐day variations when measured during the LF periods. Mean plasma leptin levels were higher for LF (7.77 ± 0.76 ng/mL; mean ± SE) than for SF periods (3.95 ± 0.16 ng/mL; mean ± SE). Although plasma leptin concentration did not show any change after feeding in the SF and LF periods, plasma insulin and glucose levels increased within 15 min after liquid abomasal feeding, but not after solid ruminal feeding. The high plasma leptin concentration during the LF periods in weaned sheep could be due to change of digestible energy intake and changes in plasma insulin and glucose levels accompanying the changes in digestive processes and nutrient supply.  相似文献   

How weed control and fertilisation influence tree physiological processes and growth at early establishment in an exotic F<Subscript>1</Subscript> hybrid pine plantation of subtropical Australia     

Paula?T.?IbellEmail author  Zhihong?H.?Xu  Terence?J.?Blake  Carole?Wright  Timothy?J.?Blumfield 《Journal of Soils and Sediments》2014,14(5):872-885

  相似文献   

Influence of Reducing Conditions on Solubility of Trace Metals in Contaminated Soils   总被引：1，自引：0，他引：1  

Charlatchka  R.  Cambier  P. 《Water, air, and soil pollution》2000,118(1-2):143-168

Dissolved trace metals Cd, Pb, Zn, andother solutes were determined after reducingconditions have been imposed to samples of anagricultural polluted soil. The ploughed layer wassampled as undisturbed blocks for floodingexperiments, and sieved samples were incubated inaqueous suspensions at controlled pH (pH 6.2) underdifferent redox conditions. Redox potential and pH,concentrations of major and trace elements, andorganic and inorganic ligands, were measured in thesolutions. Their chemical speciation was calculated byusing the programme Soilchem.These experiments and calculations have shown that pHvariations definitively influence trace metalsolubility, whatever they are induced by reductivedissolution, organic acid formation, or otherprocesses, and that strong acidification can beobtained with well buffered soil when about 1%available carbon is anaerobically transformed intoorganic acids. The organic acids also intervene bycomplexation, particularly for Pb. On another hand,denitrification can limit these effects by consumingprotons and organic substances. Given a steady pH,reducing conditions enhance the mobility of tracemetals, at first by dissolution of manganic and ferricoxides; Pb appeared more sensitive to these processesthan Zn, and finally Cd. As a general rule,hydromorphy in a well-buffered contaminated soil at afirst step should increase the mobility of divalenttrace metals, by decreasing pH and reducing Mn and Feoxides, but prolonged flooding can lead to fix tracemetals again, rather by re-adsorption or precipitationphenomena than by formation of insoluble sulphides.  相似文献   

Aquaculture Animal Welfare and Animal Rights          下载免费PDF全文

Carole R. Engle 《Journal of the World Aquaculture Society》2018,49(4):642-643

  相似文献   

Morbillivirus infection in two common porpoises (Phocoena phocoena) from the coasts of England and Scotland.     

S Kennedy  T Kuiken  H M Ross  M McAliskey  D Moffett  C M McNiven  M Carole 《The Veterinary record》1992,131(13):286-290

Two common porpoises (Phocoena phocoena), one found stranded on the Isle of Sheppey, Kent, and the other in the Moray Firth, Scotland, in late 1990, were examined post mortem. Lesions of diffuse bronchointerstitial pneumonia were present in both animals; they were characterised by the infiltration of alveoli with leucocytes, macrophages and multinucleate syncytia, the necrosis of bronchial and bronchiolar epithelium, focal proliferation of type II pneumocytes and occasional acidophilic cytoplasmic inclusions in alveolar macrophages and syncytia. Lymphoid depletion was apparent in the spleen, thymus and lymph nodes of both porpoises. Other changes in the Isle of Sheppey porpoise included severe dacryoadenitis. Marked pharyngitis, oesophagitis and balanoposthitis were present in the Moray Firth porpoise. Immunoperoxidase staining revealed the presence of morbillivirus antigen in a range of epithelia from both porpoises. This is the first report of morbillivirus infection in cetaceans from the coast of Great Britain.  相似文献   

Why Interdisciplinary Research is Critical for the Growth and Development of Aquaculture          下载免费PDF全文

Carole R. Engle 《Journal of the World Aquaculture Society》2016,47(2):149-151

  相似文献   

Economics of Intensively Aerated Catfish Ponds          下载免费PDF全文

Ganesh Kumar  Carole Engle 《Journal of the World Aquaculture Society》2017,48(2):320-332

The US catfish industry is evolving by adopting production‐intensifying practices that enhance productivity. Catfish producers have increased aeration rates over time, and some now use intensive rates of aeration (>9.33 kW/ha). Costs and production performance were monitored at commercial catfish farms using high levels of aeration (11.2–18.7 kW/ha) in Alabama, Arkansas, and Mississippi. A multivariate‐cluster analysis was used to identify four different management clusters of intensively aerated commercial catfish farms based on stocking density, size of fingerlings at stocking, and feed conversion ratios (FCR). Breakeven prices of hybrid catfish raised in intensively aerated pond systems were estimated to range from $1.86/kg to $2.17/kg, with the lowest costs associated with the second greatest level of production intensity. The two medium‐intensity clusters generated sufficiently high revenues for long‐term profitability. However, the least‐intensive and the most‐intensive clusters were economically feasible only when catfish and feed prices were closer to less probable market prices. Feed price, FCR, and yield contributed the most to downside risk. Intensive aeration in catfish ponds, up to the levels analyzed in this study, appears to be economically feasible under the medium‐intensity management strategies identified in this analysis.  相似文献