Assessment of Compensatory Growth in Channel Catfish Ictalurus punctatus R. and Associated Changes in Body Condition indices     

I. Gibson  Gaylord Delbert M.  Gatlin III 《Journal of the World Aquaculture Society》2000,31(3):326-336

A feeding trial was undertaken to evaluate compensatory growth in channel catfish and to chronicle the changes in body condition associated with the imposed feeding strategy. Four 1200-L circular tanks were each stocked with approximately 600 fingerling channel catfish (mean initial weight 32 g). Two tanks represented control fish which were fed to apparent satiation once daily throughout the trial. The two remaining tanks of fish were unfed for 4 wk and subsequently refed daily to apparent satiation for the following 10 wk in order to elicit a compensatory growth response. Fish fed to apparent satiation during the first 4 wk of the trial had a 41% increase in body weight, while the fasted fish decreased in weight by 20%. During the subsequent refeeding period, previously unfed fish were not able to increase growth rates sufficiently to overcome weight loss imposed by the 4-wk feed restriction. However, after 8 wk of refeeding, total increase in body weight of the previously unfed fish was 179 % of initial weight and similar to that of control fish which gained 231 % of initial weight. Hepatosomatic index (HSI) and condition factor decreased rapidly during the fasting period and increased rapidly to control levels during subsequent refeeding. The intraperitoneal fat (1PF) ratio and muscle ratio responded more slowly to feed restriction with IPF ratio decreasing consistently after 2 wk feed restriction. Muscle ratio showed little effect from the 4-wk period of feed deprivation. It appears that not feeding channel catfish fingerlings for 4 wk is too long to induce a compensatory growth response that is optimal for aquaculture; however, HSI may be the index of choice for detecting when refeeding should begin to maximize compensatory growth.  相似文献   

Dissociation of individual molecules with electrons from the tip of a scanning tunneling microscope     

Dujardin G  Walkup RE  Avouris P 《Science (New York, N.Y.)》1992,255(5049):1232-1235

The scanning tunneling microscope (STM) can be used to select a particular adsorbed molecule, probe its electronic structure, dissociate the molecule by using electrons from the STM tip, and then examine the dissociation products. These capabilities are demonstrated for decaborane(14) (B(10)H(14)) molecules adsorbed on a silicon(111)-(7 x 7) surface. In addition to basic studies, such selective dissociation processes can be used in a variety of applications to control surface chemistry on the molecular scale.  相似文献   

Advances in irrigation: Vol. 2. Daniel Hillel (editor). Academic Press,London, 1983. 364 pp., US$59.00/£42.00. ISBN 0-12-024302-4     

Gaylord V. Skogerboe 《Agricultural Water Management》1984,9(3):260-263

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Sensory Analysis of Rainbow Trout,Oncorhynchus mykiss,Fed Enriched Black Soldier Fly Prepupae,Hermetia illucens     

Wendy M. Sealey  T. Gibson Gaylord  Frederic T. Barrows  Jeffery K. Tomberlin  Mark A. McGuire  Carolyn Ross  Sophie St‐Hilaire 《Journal of the World Aquaculture Society》2011,42(1):34-45

A growth trial and fillet sensory analysis were conducted to examine the effects of replacing dietary fish meal with black soldier fly (BSF) prepupae, Hermetia illucens, in rainbow trout, Oncorhynchus mykiss. A practical‐type trout diet was formulated to contain 45% protein; four test diets were developed by substituting 25 and 50% of the fish meal with normal (BSF) or fish offal‐enriched black soldier fly (EBSF) prepupae. Dietary fat was adjusted to approximately 20% lipid using fish oil and poultry fat. Diets were fed to three replicate tanks of fish per treatment (10 fish/tank) for 8 wk. After the trial, three fish per tank were sampled for determination of hepatosomatic index, intraperitoneal fat ratio and muscle ratio, and muscle proximate and fatty acid composition. Fish remaining after sampling were used for sensory evaluation. Growth of fish fed the EBSF diets was not significantly different from those fish fed the fish meal‐based control diet, while the growth of fish fed the BSF diets was significantly reduced as compared to the control diet. A group of 30 untrained panelists did not detect a significant difference in a blind comparison of fish fed the fish meal containing control diet as compared to fish fed the EBSF or BSF diets.  相似文献   

Evaluation of ingredient combinations from differing origins (fishmeal,terrestrial animal and plants) and two different formulated nutrient targets on rainbow trout growth and production efficiency          下载免费PDF全文

T.G. Gaylord  W.M. Sealey  F.T. Barrows  C.A. Myrick  G. Fornshell 《Aquaculture Nutrition》2017,23(6):1319-1328

A 12‐week trial was performed with rainbow trout (Oncorhynchus mykiss) utilizing combinations of ingredients at two nutrient targets. Ingredient combinations were fishmeal‐based diet (FMD), animal product‐based diet (APD), plant product‐based diet (PPD), novel plant‐based diet (NPD) and potential future plant‐based diet (FPD). Two nutrient concentrations were targeted: 1) to meet published amino acid targets for rainbow trout utilizing approximately 450 g/kg crude protein (400–420 g/kg digestible protein) and 2) to meet the amino acid targets based on ideal amino acid balance of trout muscle for Lys, Met and Thr utilizing approximately 400 g/kg crude protein (370–380 g/kg digestible protein). Interactive effects between ingredient combination and nutrient concentration occurred across all response variables. When diets were formulated to Target 1, fish consuming FMD and APD displayed better weight gain and feed conversion ratio (FCR) than plant‐based diet, while graded effects were found within the plant‐based treatments. When differing ingredient combinations were utilized and formulated to Target 2, fish grew equally well except for the NPD treatment which supported lower growth and higher FCR. Based on the data from the current experiment, one can completely remove fishmeal from trout feeds and reduce protein levels when dietary digestible amino acids are balanced.  相似文献   

Impact of plant cell wall network on biodegradation in soil: Role of lignin composition and phenolic acids in roots from 16 maize genotypes     

Gaylord Erwan Machinet  Isabelle Bertrand  Yves Barrière  Sylvie Recous 《Soil biology & biochemistry》2011,43(7):1544-1552

Residue quality is a key factor governing biodegradation and the fate of C in soil. Most investigations of relationships existing between crop residue quality and soil decomposition have been based on determining the relative proportions of soluble, cellulose, hemicellulose and lignin components. However, cell wall cohesion is increased by tight interconnections between polysaccharides and lignin that involve cross-linking agents (phenolic acids). The aim of this study was to determine the role of lignin composition and phenolic acids on short- to medium-term decomposition of maize roots in soil. Sixteen maize genotypes, presenting a range of chemical characteristics related to root lignin and phenolic acids, were used. The main components were characterized by Van Soest (VS) extraction and cell wall acid hydrolysis, and the non-condensed Syringyl and Guaicyl lignin monomers, esterified phenolic acids and etherified phenolic acids were determined. Maize roots were then incubated in soil under controlled conditions (15 °C, −80 kPa moisture) for 796 days. Results showed that VS extraction over-estimated the structural hemicellulose content and that VS lignin was more recalcitrant than Klason lignin. The tremendous effect of cell wall chemical characteristics was shown by marked variations (almost two-fold differences in C mineralization), between the 16 maize roots. Decomposition was controlled by soluble residue components in the short term whereas lignin and the interconnections between cell wall polymers were important in the long-term. Notably the cell wall domain rich in non-condensed lignin and esterified phenolic acids was prone to decomposition whereas the presence of etherified ferulic acids seemed to hamper cell wall decomposition.  相似文献   

Pesticide Use and Mycotoxin Production in Fusarium and Aspergillus Phytopathogens     

J.P. Felix D'Mello  Ann M.C. Macdonald  David Postel  Wilko T.P. Dijksma  Aude Dujardin  Cristina M. Placinta 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(8):741-751

The major mycotoxigenic species of Fusarium and Aspergillus phytopathogens have been identified in this review. Since fungicides are widely used to control crop diseases caused by these fungi, it is pertinent to assess efficacy with respect to mycotoxin production. In both laboratory studies with pure cultures of phytopathogens and field trials with crop plants, the overall evidence concerning the effectiveness of fungicides is contradictory and in certain cases somewhat unexpected. In particular, at sub-lethal doses of a number of fungicides including carbendazim, tridemorph, difenoconazole and tebuconazole with triadimenol, mycotoxin production from Fusarium phytopathogens may increase. Furthermore, the efficacy of propiconazole and thiabendazole in the control of deoxynivalenol production from F. graminearum is not consistent. Evidence has been presented to suggest, for the first time, that fungicide-resistance in F. culmorum may be accompanied by a more persistent pattern of mycotoxin production. The limited evidence on the effects of fungicides on mycotoxin production in Aspergillus species is also conflicting. Under laboratory conditions, miconazole and fenpropimorph have been shown to increase aflatoxin production from A. parasiticus. Moreover, fenpropimorph increased production of the more toxic aflatoxin B1. Since fungal infection of plant products is often preceded by insect damage, there is interest in the effectiveness of insecticides to reduce infestation, infection and mycotoxin contamination. Additionally, insecticides may be effective in their own right, causing a direct effect on mycotoxin synthesis. The bulk of the evidence relates to effects on aflatoxin (AF) components B1, B2, G1 and G2. Under laboratory conditions, AFB1 production was most resistant to inhibition by insecticides, followed by AFG1, AFG2 and AFB2. This pattern of inhibition was particularly consistent for the organophosphorus insecticides. In one field study, Bux and carbaryl were considerably more effective than naled in reducing AFB1 contamination of maize kernels. It is concluded that if pesticide control is to be more effective in the future, additional criteria may be required in developing evaluation protocols for candidate compounds. In particular, the issue of fungicide-resistance in relation to mycotoxin production needs to be addressed in a concerted programme of research. Additionally, the potential of breeding and selecting cultivars resistant to disease caused by toxigenic fungi needs to be exploited in a parallel search for an environmentally acceptable solution to the question of mycotoxin contamination of plant products.  相似文献   

Fertility improvement in tetraploid pearl millet     

M. Dujardin  W. W. Hanna 《Euphytica》1989,42(3):285-289

Summary Autotetraploid (2n=4x=28) pearl millet inbred lines, Tift 23BE and Tift 239DB, have been developed for use in crosses with other polyploid Pennisetum species. Each line set less than 1% and 3% selfed and open-pollinated seed, respectively. Seed germination was usually less than 17%. First generation (F₁) hybrids between the two inbreds set up to 61% seed while up to 40% of the seed from hybrids germinated.Seed weight per inflorescence for two planting dates averaged 0.32 g and 3.06 g for the two inbreds and the second generation F₂ progeny, respectively. One hundred seed weight was also significantly higher (0.78 g vs 0.48 g) in the F₂ progeny, probably due better endosperm development. Chromosome behavior and pollen stainability were similar in the inbred parents and hybrids. However, the hybrids shed more pollen than the inbred parents.Heterosis was evident in the F₁ hybrids and F₂ progeny which showed significant increases in plant height, leaf length, leaf width, and inflorescence length in addition to fertility improvement.  相似文献   

Participation of the TATA factor in transcription of the yeast U6 gene by RNA polymerase C   总被引：35，自引：0，他引：35  

F Margottin  G Dujardin  M Gérard  J M Egly  J Huet  A Sentenac 《Science (New York, N.Y.)》1991,251(4992):424-426

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Saline and sodic soils: Principles — Dynamics — Modeling: E. Bresler,B.L. McNeal,and D.L. Carter. Springer-Verlag,Berlin/Heidelberg/New York, 1982. x + 236 pp., US$43.00/DM98.00. ISBN 3-540-11120-4     

Gaylord V. Skogerboe 《Agricultural Water Management》1984,9(1):80

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