Sex-Reversal of Oreochromis aureus by Immersion in Mibolerone,a Synthetic Steroid 1     

Les Torrans  Frank Meriwether  Fran Lowell  Bill Wyatt  Paul D. Gwinup 《Journal of the World Aquaculture Society》1988,19(2):97-102

Mibolerone (MI), a synthetic steroid, was used to sex-reverse undifferentiated Oreochromis aureus fry. Fry were exposed to 0.0, 0.3, 0.6, or 1.0 ppm MI in static-water solutions for five weeks (immersion treatments) or were fed a diet containing 1.0 ppm MI for four weeks in a flow-through system. Following hormone treatment, the fish were grown to over 60 mm total length prior to sex determination using gonadal squash examination. Fish immersed in 1.0, 0.6, or 0.3 ppm MI had average tissue MI concentrations of 14.4, 5.6, and 3.3 ppm, respectively. Immersion in either 1.0 or 0.6 ppm MI for five weeks resulted in an average of 82% males and 18% ovo-testicular fish (inter-sex fish) with no gonadal females being produced. Exposure to 0.3 ppm MI resulted in 78.7% males, 20.7% ovo-testicular fish, and 0.7% gonadal females. Feeding a diet containing 1.0 ppm MI resulted in 85% males, 11% ovo-testicular fish, and 4% gonadal females. Fry growth and survival were negatively correlated with the MI concentration of the immersion treatments. Exposing tilapia fry to static-water solutions of 0.6 ppm MI for five weeks appears to be a feasible method of eliminating the production of functional females. Immersion solutions should be changed at least weekly to maintain an effective hormone concentration.  相似文献   

Rapport General     

Les Rapporteurs Généraux L. de Saint Rat  Dr. Didier Bertrand 《Plant foods for human nutrition (Dordrecht, Netherlands)》1968,16(1-4):1-6

Sans résumé  相似文献   

Molecular ecological analysis of porcine ileal microbiota responses to antimicrobial growth promoters   总被引：1，自引：0，他引：1  

Collier CT  Smiricky-Tjardes MR  Albin DM  Wubben JE  Gabert VM  Deplancke B  Bane D  Anderson DB  Gaskins HR 《Journal of animal science》2003,81(12):3035-3045

Cultivation-independent microbial molecular ecology approaches were used to examine the effects of antibiotic growth promoters on the pig ileal microbiota. Five-week-old barrows were fitted with a simple T-cannula at the distal ileum. Three diets meeting or exceeding the minimum nutrient requirements were fed for 5 wk and supplemented as follows: 1) negative control (no antibiotic; n = 5), 2) continuous tylosin administration (n = 5), and 3) an antibiotic rotation sequence (wk 1, chlorotetracycline sulfathiazole penicillin; wk 2, bacitracin and roxarsone; wk 3, lincomycin; wk 4, carbadox; wk 5, virginiamycin; n = 5). Ileal luminal contents were collected for DNA isolation at the end of each of the 5 wk of the testing period. The V3 region of 16S rDNA was amplified by PCR and analyzed via denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction (qPCR). Resulting PCR-DGGE band numbers (bacterial species) were counted, and the banding patterns analyzed by calculating Sorenson's pairwise similarity coefficients (C(S)), an index measuring bacterial species in common among samples. Band numbers and total bacterial DNA concentrations decreased (P < 0.05) temporally in antibiotic-treated pigs compared with controls. Comparisons between treatments yielded low intertreatment C(S) indices, indicating treatment-dependent alterations in banding patterns, whereas intratreatment comparisons revealed increased homogeneity in antibiotic-treated vs. control pigs. Sequence analysis of treatment-specific bands identified three Lactobacillus, one Streptococcus, and one Bacillus species that were diminished with antibiotic rotation treatment, whereas tylosin selected for the presence of L. gasseri. Lactobacillus-specific qPCR was performed and analyzed as a percentage of total bacteria to further evaluate the effects of antibiotic administration on this genus. Total bacteria were decreased (P < 0.05) by tylosin and rotation treatments, whereas the percentage of lactobacilli increased (P < 0.05) by d 14 and through d 28 in tylosin-treated pigs. The decrease in total bacteria by antibiotics may reduce host-related intestinal or immune responses, which would divert energy that could otherwise be used for growth. Conversely, the ability of tylosin to improve animal growth may relate to its apparent selection for lactobacilli, commensals known to competitively exclude potentially pathogenic species from colonizing the intestine.  相似文献   

The effect of feed intake on ileal rate of passage and apparent amino acid digestibility determined with or without correction factors in pigs     

Albin DM  Wubben JE  Smiricky MR  Gabert VM 《Journal of animal science》2001,79(5):1250-1258

The apparent ileal digestibilities of amino acids and rate of passage were evaluated in pigs (BW = 78.3 +/- 7.4 kg) fed a semipurified diet. The pigs were fed 1.82, 2.73, or 3.65 kg DMI/d. The highest level of feed intake was considered to be ad libitum feeding. The pigs were fed according to a 3 x 3 Latin square design and were allowed to adapt to each experimental diet for 5 d. This was followed by 1 d of continuous collection of ileal digesta and a 2nd d of continuous collection separated into six 2-h postprandial time blocks. Ytterbium chloride hexahydrate was used to determine rate of passage. The ileal digestibilities of amino acids and rate of passage were unaffected (P > 0.05) by level of feed intake. The use of correction factors to more accurately express amino acid concentrations in the diet and digesta affected (P < 0.05) the apparent ileal digestibility coefficients of some amino acids.  相似文献   

Adenoma of the nasal turbinate in a sheep          下载免费PDF全文

Gabor LJ 《The Canadian veterinary journal. La revue veterinaire canadienne》2004,45(4):338-339

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Bioefficacy of L-lysine sulfate compared with feed-grade L-lysine-HCl in young pigs     

Smiricky-Tjardes MR  Mavromichalis I  Albin DM  Wubben JE  Rademacher M  Gabert VM 《Journal of animal science》2004,82(9):2610-2614

A pig growth assay was conducted to determine the relative biological value (RBV) of lysine from L-lysine sulfate compared with feed-grade L-lysine HCl. One hundred nursery pigs with an average initial BW of 9.5 +/- 1.5 kg were blocked by BW and gender and allotted randomly to five dietary treatments in five replicates of four pigs per pen. A corn-peanut meal diet containing 0.6% total lysine (as-fed basis) was supplemented with two levels (0.1 and 0.2%) of lysine from L-lysine-HCl or L-lysine sulfate. The RBV of L-lysine sulfate was determined using multiple regression slope-ratio methodology, with ADG and G:F as the response criteria. At the tested levels, linear responses for gain and G:F were obtained from increments of lysine from the two lysine sources. When ADG was regressed on supplemental lysine intake, the RBV of lysine in L-lysine sulfate was 99% of the RBV of lysine in L-lysine HCl. When G:F was regressed on supplemental lysine intake, the RBV of lysine in L-lysine sulfate was 97% of the RBV of lysine in L-lysine-HCl. The t-test analysis revealed that the RBV of lysine in L-lysine sulfate was not significantly different from the RBV of lysine in L-lysine HCl, which was assumed to be 100% bioavailable. In conclusion, L-lysine sulfate can replace L-lysine HCl in diets for growing swine.  相似文献   

Age-related morphometry of equine calcified cartilage     

Martinelli MJ  Eurell J  Les CM  Fyhrie D  Bennett D 《Equine veterinary journal》2002,34(3):274-278

Although there are many studies in the equine literature focused on articular diseases and the aetiology of osteoarthritis, few have concentrated on normal articular structures and how they change with age. The objective of this investigation was to study the thickness and morphology of the calcified cartilage layer of the distal metacarpus over a range of ages. A parasagittal slab of bone was sectioned from the region of sesamoid contact on the medial condyle of the metacarpi from 34 horses. The slab of bone was preserved, dehydrated and embedded, undecalcified, in methylmethacrylate and then stained with toluidine blue. Six repeatable fields of interest from the distal aspect of each metacarpus were digitised and examined to determine the morphology of the calcified cartilage layer. The thickness of the calcified cartilage, range 88-426 microm, was estimated using a method of integration. The results indicate an age-related influence on the thickness of the calcified cartilage layer, generally increased in older horses. While this finding is significant, perhaps more importantly a positional relationship was also identified, indicating that pressures endured by different regions within a joint may dictate morphological development of the tissues. This study has begun to lay the groundwork to determine whether the calcified layer of the hyaline cartilage could be involved in the development of osteoarthritis.  相似文献   

Changes in small intestinal nutrient transport and barrier function after lipopolysaccharide exposure in two pig breeds     

Albin DM  Wubben JE  Rowlett JM  Tappenden KA  Nowak RA 《Journal of animal science》2007,85(10):2517-2523

Specific pig breeds with unique characteristics have been developed, and the current study sought to characterize some of these differences. Using modified Ussing chambers, electrophysiological mucosal transport of D-glucose, L-Gln, L-Pro, L-Arg, L-Thr, and glycylsarcosine was assessed in small intestinal tissues (duodenum, jejunum, ileum) taken from Yorkshire-based hybrid (BW = 142.4 +/- 2.0 kg; mean age = 8 mo) and Meishan (BW = 65.8 +/- 0.8 kg; mean age = 6 mo) female pigs after 4 h of lipopolysaccharide (LPS) exposure. Gilts were randomly assigned to control (saline infusion; n = 6 Yorkshires, n = 5 Meishans) or LPS (n = 7 Yorkshires, n = 5 Meishans) groups. Therefore, treatments were arranged in a 2 (breed) x 2 (LPS infusion) factorial. Four hours after infusions, pigs were euthanized, and intestinal segment samples were removed. Glucose transport in the ileum was decreased (P < 0.001) in Yorkshires with LPS but was increased (P < 0.001) by over 2-fold in Meishans with LPS. After LPS infusion, Pro transport was increased in duodenum (over 5-fold; P = 0.04) and ileum (over 10-fold; P < 0.001) of Meishans but was unaffected in Yorkshires. Arginine transport in the ileum of control Meishans was greater (P = 0.05) than Arg transport in control Yorkshires. Glycylsarcosine transport was greater (P = 0.02) in Meishans than Yorkshires (nearly 2-fold), regardless of LPS provision. Glycylsarcosine transport was increased (P = 0.003) over 2-fold by LPS, regardless of pig breed. Resistance (barrier function) was increased (P = 0.03) by LPS in Yorkshires but was unaffected in Meishans. The current study indicates that small intestinal function responded differently to LPS in Yorkshire and Meishan gilts and that these effects were nutrient- and segment-dependent.  相似文献   

US grower perceptions and experiences with glyphosate-resistant weeds     

Foresman C  Glasgow L 《Pest management science》2008,64(4):388-391

BACKGROUND: A survey of 400 growers of maize, soybeans and cotton was made in the United States to determine perceptions, experiences and management practices with glyphosate-resistant weeds. The survey included growers in the north (corn belt) and south (cotton belt) of the USA in spring 2006. RESULTS: Interestingly, 24 and 39% of northern and southern growers, respectively, assumed they had glyphosate weed resistance on their farm. Of the 200 southern growers interviewed, 67% had planted continuous glyphosate-resistant (GR) crops for a period of 3-5 years. According to the survey respondents, the key method for managing glyphosate-resistant weeds was to rotate to other herbicides. CONCLUSION: Growers do value GR crop technology but are adopting measures to manage resistance only as needed.  相似文献   

Urban forest assessment in Bangkok,Thailand     

Montri Intasen  Richard J. Hauer  Les P. Werner  Eric Larsen 《Journal of Sustainable Forestry》2017,36(2):148-163

The objective of this study was to conduct an urban forest assessment for Bangkok and pilot the appropriateness of adapting the i-Tree Eco International software in Thailand. Urban forest structure, function, and value were estimated from 184 stratified random sample plots. A total 48 tree species were encountered and the three most common that contributed 34.1% of total tree population were Polyalthia longifolia Sonn. (15.7%), Mangifera indica L. (13.0%), and Pithecellobium dulce (Roxb.) Benth. (5.4%). The majority of trees (approximately 70%) were <23 cm in diameter. An estimated 2.5 (0.4 SEM) million trees with a canopy cover of 8.6% (1.3 SEM) exist in the Bangkok study area. These trees store an approximate total of 309,700 (73,726 SEM) metric tons of carbon and sequester 16,271 (2965 SEM) metric tons of CO₂ annually. Additional research is needed to develop functional relationships for urban trees in Thailand to overcome a current limitation for using i-Tree Eco in Thailand to estimate structural and functional value of urban forests. Study results also provide land-use planners information on the current urban forest resource and the potential for future urban greening.  相似文献