Responses of apple fruit size to tree water status and crop load     

Naor A  Naschitz S  Peres M  Gal Y 《Tree physiology》2008,28(8):1255-1261

The combined effects of irrigation rate and crop load on apple yield and fruit size were examined in two commercial apple orchards (cv. Golden Delicious) in a semi-arid zone. The irrigation rates applied were 1, 3 and 7 mm day(-1), and the two fruit thinning treatments involved adjusting crop load to 100 and 300 fruits per tree at Ortal and 50 and 150 fruits per tree at Matityahu. Unthinned trees served as the control. The fruit from each tree was picked separately, and fruit size distribution was determined with a commercial grading machine. Midday stem water potentials varied from -0.9 to -2.8 MPa, crop load varied from 80,000 to 1,900,000 fruit ha(-1) and crop yield varied from 10 to 144 Mg ha(-1). Midday stem water potential decreased with increasing crop load in all irrigation treatments at Matityahu, but only in the 1 mm day(-1) treatment at Ortal. The extent of the lowering of midday stem water potential by crop load decreased with increasing soil water availability. At both orchards, a similar response of total crop yield to crop load on a per hectare basis was observed. Mean fruit mass and relative yield of fruit > 70 mm in diameter increased with midday stem water potential, with the low crop loads having similar but steeper slopes than the high crop load. The responses of mean fruit mass and relative yield of fruit > 70 mm in diameter to midday stem water potential were similar at both orchards, perhaps indicating that thresholds for irrigation scheduling are transferable to other orchards within a region. Factors that may limit the transferability of these thresholds are discussed.  相似文献   

Influence of temperature on protein utilization in juvenile European seabass (Dicentrarchus labrax)     

Helena Peres  Aires Oliva-Teles 《Aquaculture (Amsterdam, Netherlands)》1999,170(3-4):337-348

The aim of this trial was to study the utilization of dietary protein by seabass juveniles with 5.5 g mean body weight, at two water temperatures: 18°C and 25°C. For that purpose, the fish were fed for 12 weeks, four isoenergetic diets with different protein levels (36, 42, 48, and 56%). At the end of the trial, growth rate and feed utilization were significantly better at the higher water temperature. Within each temperature, specific growth rate and feed efficiency were significantly higher with the 48 and 56% protein diets than with the other diets. At 25°C, feed efficiency was also significantly better with the 56% than with the 48% protein diet. N retention (g kg average body weight⁻¹ day⁻¹) was higher at 25°C than at 18°C but, as a % N intake the inverse was true. Although at 25°C N retention (% N intake) was not different among groups, retention in g kg ABW⁻¹ day⁻¹ was significantly higher with the 56% protein diet than with 36 and 42% protein diets. On the contrary, at 18°C N retention (g kg ABW⁻¹ day⁻¹) was similar among groups while as a percentage of N intake it was inversely related to the dietary protein level. Regarding energy utilization, at each temperature, there were no differences among dietary treatments on energy retention (g kg ABW⁻¹ day⁻¹). As a % of energy intake, energy retention significantly increased with the increase of dietary protein level at 25°C, while at 18°C, there were no significant differences among groups. Within each temperature, at the end of the trial, there were no differences among groups in proximate composition of whole fish. Apparent digestibility coefficients of dry matter, protein and energy significantly improved with the increase of water temperature but, within each temperature, there were no significant differences among groups. The results of this study indicate that, regardless of water temperature, the dietary protein requirement for growth seems to be satisfied with a diet containing 48% protein. Growth and feed efficiency were significantly higher at the higher temperature, however, protein utilization was more efficient at the lower temperature.  相似文献   

Competitive effects between rainbow trout and Atlantic salmon in natural and artificial streams          下载免费PDF全文

Aimee Lee S. Houde  Andrew D. Smith  Chris C. Wilson  Pedro R. Peres‐Neto  Bryan D. Neff 《Ecology of Freshwater Fish》2016,25(2):248-260

Competition with non‐native species may impede the restoration of native species, but differences in competitive abilities among intraspecific native populations may make some populations more suitable for reintroduction than others. Here, juvenile Atlantic salmon (Salmo salar) from two allopatric populations (LaHave and Sebago) being used for reintroduction into Lake Ontario were placed into two natural stream sites differing in the presence of ecologically similar rainbow trout (Oncorhynchus mykiss). We assessed the effects of competition in the natural streams on fitness‐related traits and habitat use of the Atlantic salmon. We then compared these effects to those observed in artificial streams from a previous study. Atlantic salmon in natural streams had reduced fitness‐related traits that were associated with suboptimal microhabitats in the presence of rainbow trout, but utilised optimal microhabitats in their absence. In the presence of rainbow trout, the two Atlantic salmon populations exhibited comparable recapture proportions to each other, but the individuals from the Sebago population had better performance (body size and condition) than those from the LaHave population. Responses of both Atlantic salmon populations to competition with rainbow trout were generally similar in both direction and magnitude when compared to results from the artificial stream study. The combined results suggest that native species restoration efforts should be focused on candidate populations that are ecologically suitable to reintroduction environments, as well as on suitable habitats that do not contain exotic competitors. Moreover, this study highlights the value of controlled experiments in artificial environments for predicting fitness‐related performance in natural environments.  相似文献   

Evaluation of ethanedinitrile (EDN) as a preplant soil fumigant in Florida strawberry production     

Jialin Yu  Juliana S Baggio  Nathan S Boyd  Josh H Freeman  Natalia A Peres 《Pest management science》2020,76(3):1134-1141

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Selection for Pathogenicity to Strawberry in Populations of Colletotrichum gloeosporioides from Native Plants     

Mackenzie SJ  Seijo TE  Legard DE  Timmer LW  Peres NA 《Phytopathology》2007,97(9):1130-1140

ABSTRACT Colletotrichum gloeosporioides causes a serious crown rot of strawberry and some isolates from native plants are pathogenic to strawberry. C. gloeosporioides from lesions on wild grape and oak were sampled at two sites adjacent to commercial strawberry fields in Florida and two distant sites. Random amplified polymorphic DNA (RAPD) marker data and restriction enzyme digests of amplified rDNA were used to determine whether isolates were from the same C. gloeosporioides subgroup that infects strawberry. There were 17 to 24 native host isolates from each site that clustered with a group of strawberry crown isolates based on RAPD markers. Among strawberry isolates, there were two rDNA genotypes identified by restriction enzyme analysis. Both genotypes were present among native host isolates sampled from all four sites. There was some evidence that the different rDNA genotypes differentiated two closely related subpopulations, although the proportion of pathogenic isolates from native hosts among the two different genotypes was not different. The incidence of isolates pathogenic to strawberry was greater at sites close to strawberry fields relative to sites distant from strawberry fields for isolates with a BstUI(-)/MspI(+) rDNA genotype (44 versus 13%), a BstUI(+)/MspI(-) genotype (57 versus 16%), or when both genotypes were analyzed together (46 versus 15%). Based on these results, it appears that the C. gloeosporioides subgroup that causes crown rot on strawberry is widely distributed in Florida and that selection for pathogenicity on strawberry occurs in the area where this host is grown in abundance.  相似文献   

Global network reorganization during dynamic adaptations of Bacillus subtilis metabolism     

Buescher JM  Liebermeister W  Jules M  Uhr M  Muntel J  Botella E  Hessling B  Kleijn RJ  Le Chat L  Lecointe F  Mäder U  Nicolas P  Piersma S  Rügheimer F  Becher D  Bessieres P  Bidnenko E  Denham EL  Dervyn E  Devine KM  Doherty G  Drulhe S  Felicori L  Fogg MJ  Goelzer A  Hansen A  Harwood CR  Hecker M  Hubner S  Hultschig C  Jarmer H  Klipp E  Leduc A  Lewis P  Molina F  Noirot P  Peres S  Pigeonneau N  Pohl S  Rasmussen S  Rinn B  Schaffer M  Schnidder J  Schwikowski B  Van Dijl JM  Veiga P  Walsh S  Wilkinson AJ  Stelling J  Aymerich S 《Science (New York, N.Y.)》2012,335(6072):1099-1103

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Evaluation of Soy Protein Concentrate and Meat and Bone Meal as a Replacement for Fish Meal in the Diet of Nile Tilapia Fingerlings          下载免费PDF全文

Manoel Joaquim Peres Ribeiro  Rose M. Vidotti  Leandro A. Ferreira  Giovani Sampaio Gonçalves 《Journal of the World Aquaculture Society》2016,47(3):369-375

This experiment evaluated soy protein concentrate (SPC) and meat and bone meal as a replacement for fish meal protein (FP) in the diet of Nile tilapia fingerlings. Five diets were evaluated including a control diet (50.0% crude protein [CP], of which half the protein came from fish meal [FM]), and four diets in which FM was replaced by increasing amounts of SPC (25.5, 50.0, 75.5, and 100.0%) in combination with meat and bone meal. At the conclusion of a 60‐d growth trial, the following parameters were determined: final weight (FW), final length (FL), weight gain (WG), feed intake (FI), apparent feed conversion (AFC), survival (SUR), and production cost. The estimate of the best replacement value was determined by polynomial regression and the linear response plateau. The results showed significant (P < 0.05) improvement for WG and AFC ratio as FM was gradually replaced by SPC. The parameters FL and FI reached their optimum value at a replacement level of 100% SPC. These results show that it is feasible to use a combination of SPC and meat and bone meal in a balanced feed formulation as an alternative protein source in the diets of Nile tilapia fingerlings.  相似文献   

Effect of eFSH on Ovarian Cyclicity and Embryo Production of Mares in Spring Transitional Phase   总被引：1，自引：0，他引：1  

K.R. Peres  C.B. Fernandes  M.A. Alvarenga  F.C. Landim-Alvarenga 《Journal of Equine Veterinary Science》2007,27(4):176-180

The use of equine FSH (eFSH) for inducing follicular development and ovulation in transitional mares was evaluated. Twenty-seven mares, from 3 to 15 years of age, were examined during the months of August and September 2004, in Brazil. Ultrasound evaluations were performed during 2 weeks before the start of the experiment to confirm transitional characteristics (no follicles larger than 25 mm and no corpus luteum [CL] present). After this period, as the mares obtained a follicle of at least 25 mm, they were assigned to one of two groups: (1) control group, untreated; (2) treated with 12.5 mg eFSH, 2 times per day, until at least half of all follicles larger than 30 mm had reached 35 mm. Follicular activity of all mares was monitored. When most of the follicles from treated mares and a single follicle from control mares acquired a preovulatory size (≥35 mm), 2,500 IU human chorionic gonadotropin (hCG) was administered IV to induce ovulation. After hCG administration, the mares were inseminated with fresh semen every other day until ovulation. Ultrasound examinations continued until detection of the last ovulation, and embryo recovery was performed 7 to 8 days after ovulation. The mares of the treated group reached the first preovulatory follicle (4.1 ± 1.0 vs 14.9 ± 10.8 days) and ovulated before untreated mares (6.6 ± 1.2 vs 18.0 ± 11.1 days; P < .05). All mares were treated with prostaglandin F_2α (PGF_2α), on the day of embryo flushing. Three superovulated mares did not cycle immediately after PGF_2α treatment, and consequently had a longer interovulatory interval (22.4 vs 10.9 days, P < 0.05). The mean period of treatment was 4.79 ± 1.07 days and 85.71% of mares had multiple ovulations. The number of ovulations (5.6 vs 1.0) and embryos (2.0 vs 0.7) per mare were higher (P < 0.05) for treated mares than control mares. In conclusion, treatment with eFSH was effective in hastening the onset of the breeding season, inducing multiple ovulations, and increasing embryo production in transitional mares. This is the first report showing the use of FSH treatment to recover embryos from the first cycle of the year.  相似文献   

The effect of dietary protein replacement by crystalline amino acid on growth and nitrogen utilization of turbot Scophthalmus maximus juveniles     

Helena Peres  Aires Oliva-Teles   《Aquaculture (Amsterdam, Netherlands)》2005,250(3-4):755-764

A study was conducted to evaluate the effect of partial replacement of dietary fish meal by crystalline amino acids on growth performance, feed utilization, body composition and nitrogen utilization of turbot juveniles.

Four diets were formulated to be isolipidic (12% DM) and isonitrogenous (8% DM). A fish meal based diet was used as control. In the experimental diets, a crystalline amino acid (AA) mixture was used to partially replace fish meal, corresponding to a non-protein nitrogen content of 19, 37 and 56%, respectively (diets 19AA, 37AA and 56AA, respectively). The overall amino acid profile of the experimental diets resembled that of the whole-body protein of turbot. Each experimental diet was fed to triplicate groups of 20 fish (initial body weight of 31.8 g) twice daily to apparent satiation for 42 days. During the trial water temperature averaged 18 °C.

Final body weight, weight gain (g kg ABW^− 1 day^− 1) and specific growth rate were not different between the control and 19AA diet but significantly decreased with the increase of crystalline-AA inclusion from 19 to 56%. Feed intake and feed efficiency of fish fed the control and diet 19AA were similar and significantly higher than those of fish fed the 56AA diet. At the end of the growth trial, there were no significant differences in whole-body composition among groups. Hepatosomatic index was also unaffected by dietary treatments.

Nitrogen retention (g kg ABW^− 1 day^− 1) of fish fed the control and the 19AA diets were similar and significantly higher than that of fish fed the other diets. Expressed as a percentage of the nitrogen intake, N retention was significantly higher with the control than with the 37AA and 56AA diets.

Daily ammonia excretion (mg kg ABW^− 1 day^− 1) of fish fed the control diet was significantly higher than that of fish fed the 37AA and 56AA diets, while daily urea excretion (mg kg ABW^− 1 day^− 1) did not significantly differ among treatments. Non-fecal nitrogen (ammonia + urea) excretion (mg kg ABW^− 1 day^− 1) was significantly higher for fish fed the control diet than in those fed the 37AA and 56AA diets. However, as percent of N intake, ammonia excretion and non-fecal N excretion were significantly higher in fish fed the 56AA diet than in those fed the control and 19AA diets.

Specific activity of glutamate dehydrogenase, alanine and aspartate aminotransferases did not significantly differ among experimental groups.

In conclusion, in diets with an overall amino acid profile resembling that of the whole-body protein of turbot, crystalline-AA may replace 19% of dietary protein without negatively affecting growth performances or feed utilization efficiency. However, higher protein replacement levels of protein-bound-AA by crystalline-AA severely depressed growth performance.  相似文献   

Effect of dietary protein and lipid level on metabolic utilization of diets by european sea bass (Dicentrarchus labrax) juveniles     

H. Peres  A. Oliva-Teles 《Fish physiology and biochemistry》2001,25(4):269-275

Two trials were performed with sea bass juveniles to study the effect of dietary protein (trial I) and lipid (trial II) levels on the metabolic utilization of diets at 25 °C. The effect of water temperature (18 and 25 °C) on metabolism was also tested in trial I. For that purpose, oxygen consumption and ammonia excretion were measured both in fed and in 9-days starved fish. In trial I, diets were formulated to be isoenergetic (GE: 19.4 kJ g^–1) and to have 36, 42, 48 and 56% protein; in trial II, diets were formulated to be isonitrogenous (48% protein) and to have 12, 18, 24 and 30% lipid. In trial I, feed intake (g kg^–1 day^–1), and daily ammonia excretion and oxygen consumption significantly increased with water temperature. However, when expressed relatively to intake there was no significant effect of temperature on ammonia excretion (% N intake) or heat production (% GE intake). Heat increment of feeding (% GE intake) was neither affected by diet composition nor by water temperature. The relative contribution of protein catabolism to total energy expenditure significantly increased with dietary protein level, but was not affected by water temperature. In trial II, both daily ammonia excretion and oxygen consumption were inversely correlated to dietary lipid levels. Nitrogen excretion, heat production, heat increment of feeding, non-fecal losses (% intake) and the relative contribution of protein to total energy expenditure were also inversely related to dietary lipid levels. Results of this study indicate that the main effect of water temperature was to modify feed intake, not the metabolic utilization of diets. Indeed, expressed relatively to nitrogen or energy intakes, both nitrogen and energy budgets were not significantly affected by water temperature. A decrease of dietary protein to energy ratio, by modifying either dietary protein or lipid levels, spared protein utilization for metabolism, and this effect was essentially due to a decrease of non-fecal nitrogen excretion and of the heat increment of feeding.  相似文献