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51.
Investment in silvicultural techniques is notice-ably lacking,especially in breeding programs for non-con-ventional wood species.Studying genotype × environment interaction (G × E) is essential to the development of breed-ing programs.Thus,this study aimed to estimate genetic diversity of and the effects of G × E interaction on two prog-eny tests of Cordia trichotoma,including the estimation of genetic gain and genetic diversity after selection.For the experiment,30 progenies of C.trichotoma were tested at two sites with differing soil textures.Diameter at breast height (1.30 m above soil surface,dbh-cm),total height,diameter at 30 cm from the soil,first branch height,and survival were all monitored for four years.Statistical devi-ance,best linear unbiased estimator,and harmonic mean of relative performance of genetic values (MHPRVG) were all calculated to predict breeding values,estimate genetic parameters,and analyze deviance.All quantified traits varied significantly among progenies by soil type,with greatest variation recorded for genetic variability.Heritability of the progenies led to predictions of genetic gain,ranging from 7.73 to 15.45%,for dbh at four years of age.The calculated decrease in genetic diversity after selection showed that this parameter should be monitored in subsequent breed-ing cycles.G × E was low for all tests.The best-performing progenies proved most stable and best adapted to the differ-ent environmental conditions tested.  相似文献   
52.
53.
An experiment was conducted to evaluate the effect of CLA on the immune response and performance of piglets when subjected to an immune challenge. A total of 32 weanling pigs (17 to 23 d of age) with an initial BW of 8.9 kg were allotted to a 3 × 2 factorial arrangement of treatments. There were 3 levels of dietary CLA (0%, 1%, and 2%) and 2 levels of lipopolysaccharide (LPS) challenge (unchallenged and challenged). Challenged pigs were challenged on d 7 and 21. On d 4 and 18, all pigs were inoculated with BSA for assessment of IgG production. There was no difference in growth performance among piglets receiving different CLA supplementation levels. However, LPS-challenged piglets had poorer BW (P < 0.05), ADFI (P < 0.01), and ADG (P < 0.001) compared with the control group at d 35 postweaning. Lipopolysaccharide-challenged piglets also had increased respiratory rate (P < 0.001) and rectal temperature (P < 0.001), and decreased plasma proteins, hematocrit, and white blood cell counts (P < 0.05). Production of IgG against BSA was increased in the 1% CLA supplementation group (P < 0.001), indicating that CLA has an immunomodulatory effect. Supplementation with CLA did not affect lymphocyte proliferation, percentage of CD4(+) and CD8(+) cells, plasma proteins, red and white blood cell count, respiratory rate, or rectal temperature after LPS challenge. Although CLA supplementation did not influence growth performance or certain immune system measurements, the increased IgG titers with 1% CLA dietary supplementation indicate that it has a beneficial effect on the humoral immune system of weaned piglets.  相似文献   
54.
In this study, we captured 60 wild New World monkeys (Cebus spp.; Alouatta caraya) at the Paraná river basin, Paraná State, Brazil, and modified agglutination test (MAT) was performed to evaluate anti-Toxoplasma gondii antibodies. Prevalence was 30.2% (13/43) in Cebus spp. (capuchin monkeys) and 17.6% (3/17) for A. caraya (black and golden howler monkeys). MAT showed antibody titers of 16 (15/16) and 64 (1/16). Herein, we have observed an odds ratio (OR)=4.67 (1.060.05). The present work is the first report on serum occurrence of anti-T. gondii antibodies in wild capuchin monkeys and in wild black and golden howler monkeys.  相似文献   
55.
The digestive system of the capybara has been investigated because of its coprofagia habits, important for their absorptive activity. These species present differences in terms of gastrointestinal morphological characters when compared with other rodents. Macroscopiclly, the stomach of the capybara is constituted of the following parts: cardiac, pyloric, body, fundic and gastric diverticulum. It presents two curvatures, one big and another small. Externally, the presence of gastric bands (tenias) is observed. With regards to the volumetric view, the gastric capacity varies from 850 to 2010 ml, with an average of 1498.57 ml. So, the stomach of this animal can be classified as a simple stomach, in the format of a curved sack and similar to an inverted letter 'J'. The gastric mucous membrane presents a surface filled by numerous tortuous gastric folds and longitudinally distributed along all its extension. The mucous tunic also possesses recesses located among the successive gastric folds, which were denoted as gastric parts with numerous openings described as gastric pits. In the cardiac part, a glandular epithelium with cardiac glands is noticed containing a lot of parietal and mucous neck cells. The fundic part, body and gastric diverticulum contain proper gastric glands with main, parietal and mucous neck cells. Finally, the pyloric part has pyloric glands with two cellular types, mucous neck and parietal cells.  相似文献   
56.
Our study assessed the efficiency of a formulated new extender in maintaining viability and morphological integrity of Colossoma macropomum spermatozoa under chilling storage. Semen was diluted in the test extender and BTS? (Beltsville Thawing Solution) and exposed to a short‐term storage at 4.6 ± 0.6°C for 96 hr. Both extenders were able to maintain 17% ± 8% motile spermatozoa by the end of experiment. Sperm dilution in test extender did not affect the morphologically normal cells (61% ± 6%) up to 48 hr of chilling, being higher than in BTS? (50% ± 6%) (p < 0.05). After 96 hr, samples kept in the test extender had 50% of normal spermatozoa, whereas those kept in BTS? presented only 38% of normal cells. Chilling storage increased the incidence of cells with strongly coiled flagella in BTS?. Our study is the first to evaluate in detail the spermatozoa morphology as indicative of C. macropomum semen viability. The new extender was able to protect the spermatozoa against increase in coiled flagellum injuries.  相似文献   
57.
The present work reports the activities of urea cycle enzymes during the ontogenic development of the teleost pacu (Piaractus mesopotamicus). Urea cycle enzymes from the kidney and liver of adult fish were compared with those from the fish's embryonic phases. Samples were evaluated over all phases of embryonic development, the larval period and alevin. Ammonia and urea concentrations were determined during embryogenesis and in the plasma of adult fish. Except for carbamoyl phosphate synthetase-III (CPS-III), all enzymes of the urea cycle were expressed in the larvae and alevins as well as in the liver and kidney of adult fish. In spite of the low level of activity of the ornithine urea cycle (OUC) enzymes compared to those in mammals, and the low levels of tissue urea concentration compared to ammonia, the ureogenesis was evaluated in pacu. Ammonia seems to be the main nitrogenous waste during embryonic development. In this phase glutamine synthetase (GS) may play a role in ammonia detoxification, and the OUC enzymes can be individually involved in functions other than urea production. The presence of ornithine carbamoyl transferase (OCT) in all developmental phases of pacu and in the adult liver and kidney suggests that this enzyme is performing different metabolic pathways. OCT in the kidney, wherein the activity is less than in the liver, should work in the biosynthesis of polyamines and control the arginine plasma concentration given that renal arginase and argininosuccinate synthetase-argininosuccinate lyase are more active than from the liver. We suppose that OCT during the embryogenesis is a control step regulating the cellular concentration of ornithine for polyamines synthesis.  相似文献   
58.
The persistence of foot-and-mouth disease virus on wool   总被引:1,自引:0,他引:1  
SUMMARY Five Suffolk sheep, held in a high-security isolation room, were exposed for 2 hours to the aerosol of 3 mature pigs that had been infected with foot-and-mouth disease virus (FMDV), strain O1-BFS. The fleeces of 3 of the sheep were contaminated with FMDV at 2 days post exposure (dpe), while at 5 dpe the fleeces of all 5 sheep were more extensively, and more heavily, contaminated. The persistence of FMDV on contaminated wool was examined in vitro using multiple 0.5 g samples of Merino wool that were each contaminated with one of 3 strains of FMDV in tissue-culture medium: O1-BFS, O-Morocco (O-MOR 9/91) or an Asia 1 strain (TAI 1/90). Wool samples were held at either 4°C, 18°C or 37°C, and decay curves were established for each virus at each temperature. These curves predicted that O1-BFS, O-MOR 9/91 and TAI 1/90 would fall below detect-able levels at 72, 70 and 48 days post contamination (pc), respectively, for wool stored at 4°C; at 11, 12 and 12 days pc, respectively, for wool stored at 18°C; and at 57, 68 and 33 hours pc, respectively, for wool stored at 37°C. For wool contaminated with O1-BFS-infected sheep faeces, urine or blood, or with O1-BFS-infected cattle saliva, decay curves predicted virus to persist for 5 to 11 days pc at 18°C. We demonstrated that the simulated scouring of FMDV-contaminated wool at 60° to 70°C would usually reduce virus to below detectable levels. The detergent component of the scouring process had little, if any, antiviral activity, and scouring at 20°C or 50°C had limited impact on FMDV titres . We recommend that either (1) simple storage of FMDV-contaminated wool for 4 weeks at temperatures of 18°C or higher, or (2) scouring of contaminated wool at 60° to 70°C would be sufficient to remove the threat of FMDV-contaminated wool being infectious to other animals .  相似文献   
59.
The sustainability of fast-growing tropical Eucalyptus plantations is of concern in a context of rising fertilizer costs, since large amounts of nutrients are removed with biomass every 6–7 years from highly weathered soils. A better understanding of the dynamics of tree requirements is required to match fertilization regimes to the availability of each nutrient in the soil. The nutrition of Eucalyptus plantations has been intensively investigated and many studies have focused on specific fluxes in the biogeochemical cycles of nutrients. However, studies dealing with complete cycles are scarce for the Tropics. The objective of this paper was to compare these cycles for Eucalyptus plantations in Congo and Brazil, with contrasting climates, soil properties, and management practices.The main features were similar in the two situations. Most nutrient fluxes were driven by crown establishment the two first years after planting and total biomass production thereafter. These forests were characterized by huge nutrient requirements: 155, 10, 52, 55 and 23 kg ha?1 of N, P, K, Ca and Mg the first year after planting at the Brazilian study site, respectively. High growth rates the first months after planting were essential to take advantage of the large amounts of nutrients released into the soil solutions by organic matter mineralization after harvesting. This study highlighted the predominant role of biological and biochemical cycles over the geochemical cycle of nutrients in tropical Eucalyptus plantations and indicated the prime importance of carefully managing organic matter in these soils. Limited nutrient losses through deep drainage after clear-cutting in the sandy soils of the two study sites showed the remarkable efficiency of Eucalyptus trees in keeping limited nutrient pools within the ecosystem, even after major disturbances. Nutrient input–output budgets suggested that Eucalyptus plantations take advantage of soil fertility inherited from previous land uses and that long-term sustainability will require an increase in the inputs of certain nutrients.  相似文献   
60.
1. This study evaluated the effects of canola meal in broiler diets on carcass yield, carcass composition, and instrumental and sensory analyses of meat.

2. A total of 320 one-day-old Cobb broilers were used in a 35-d experiment using a completely randomised design with 5 concentrations of canola meal (0, 10, 20, 30 and 40%) as a dietary substitute for soya bean meal.

3. Polynomial regression at 5% significance was used to evaluate the effects of canola meal content. The following variables were measured: carcass yield, chemical composition of meat, and instrumental and sensorial analyses.

4. The results showed that carcass yield exhibited a quadratic effect that was crescent to the level of 18% of canola meal based on the weight of the leg and a quadratic increase at concentrations up to 8.4% of canola meal based on the weight of the chest. The yield of the chest exhibited a linear behaviour.

5. The chemical composition of leg meat, instrumental analysis of breast meat and sensory characteristics of the breast meat was not significantly affected by the inclusion of canola meal. The chemical composition of the breast meat exhibited an increased linear effect in terms of dry matter and ether extract and a decreased linear behaviour in terms of the ash content.

6. In conclusion, soya bean meal can be substituted with canola meal at concentrations up to 20% of the total diet without affecting carcass yield, composition of meat or the instrumental or sensory characteristics of the meat of broilers.  相似文献   

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