Agronomic,nutritive value,reproductive, cytogenetic,and molecular aspects of Paspalum accessions: Contribution to the development of new forage cultivars     

Frederico de Pina Matta  Alessandra Pereira Fávero  Bianca Baccili Zanotto Vigna  Marisa Toniolo Pozzobon  Sergio Raposo de Medeiros  Waldomiro Barioni Júnior  Marcelo Mattos Cavallari 《Grass and Forage Science》2023,78(1):101-118

This study investigated the agronomic, nutritive value, cytogenetic, molecular, and reproductive aspects of twenty-five Paspalum accessions to support breeding programs. The agronomic aspects and the nutritive value were evaluated in a randomized block experimental design with four replications, and with monthly repeated measures for 2 years. For the molecular characterization 16 microsatellite markers developed for different Paspalum species in previous works were used. The number of chromosomes was determined by visualizing the meiotic cells and the DNA content was determined by flow cytometry. The embryo sac clarification technique was used to characterize the reproductive system. T he results indicated genetic variability for all the variables related to yield and nutritive value. For almost all variables, the values of Paspalum accessions were higher than those of the commercial cultivars Megathyrsus maximus cv. Tanzania and Urochloa brizantha cv. Marandu, used as references. However, the accessions showed in vitro dry matter digestibility values lower than the mean value presented by the references. The groups formed in the molecular analysis showed correspondence to the groups observed in the principal components analysis, considering the variables related to yield and nutritive value. Most accessions were revealed to be tetraploid with 40 chromosomes and most accessions belonging to the Virgata group displayed a sexual embryo sac structure . Some crosses can be indicated for genetic breeding, due to a superior genomic affinity between the accessions and the higher probability of heterosis in the progeny. These results provide subsidies to genetic plant breeding programs that use these accessions.  相似文献   

Feeding selectivity in early life stages of Rhamdia voulezi under experimental conditions          下载免费PDF全文

Ariane Furtado de Lima  Maristela Cavicchioli Makrakis  Fernanda Freitas Andrade  Elaine Antoniassi Luiz Kashiwaqui  Michele de Faveri Gimenes  Sergio Makrakis 《Aquaculture Research》2017,48(4):1618-1628

The feeding selectivity of laboratory‐reared larvae of Rhamdia voulezi was assessed to investigate the preferred preys in early life stages. Three experiments were conducted at different larval development stages, starting soon after the absorption of the yolk sac (on fourth day after hatching – DAH), using zooplankton from fish ponds as food. Differences were detected in the patterns of prey selection among development stages. At first, the larvae prefer small preys, such as rotifers and cladocerans. Later, when they are more developed, they prefer to feed on large preys, such as copepods. On the fourth DAH, larvae in the pre‐flexion and initial flexion stage strongly selected rotifers and cladocerans (Diaphanosoma spinulosum, D. brevireme, Moina sp., M. micrura and M. minuta). At the other stages, cladocerans continued to be strongly selected. However, on the eighth DAH, larvae in flexion stage selected less strongly copepods Argyrodiaptomus azevedoi, Metacyclops mendocinus and Termocyclops decipiens. On the tenth DAH, larvae in postflexion stage selected more strongly copepods Argyrodiaptomus furcatus, Notodiaptomus cf. spinuliferus and M. mendocinus. As larvae grow, they tend to specialize in feeding of a particular prey. Prey selection of R. voulezi larvae was based both on species and zooplankton size. The size of the zooplankton ingested was related to the mouth gape size of larvae.  相似文献   

Effect of potential probiotic bacteria on growth and survival of tilapia Oreochromis niloticus L., cultured in the laboratory under high density and suboptimum temperature     

Juan Pablo Apún-Molina  Apolinar Santamaría- Miranda  Antonio Luna-González  Sergio F. Martínez-Díaz  & Maurilia Rojas-Contreras 《Aquaculture Research》2009,40(8):887-894

This study examined the effect of potential probiotic bacteria on growth and survival of the tilapia Oreochromis niloticus , under high density and suboptimum temperature. Presumptive Bacillus and lactic acid bacteria (LAB) were isolated from tilapia and from their culture system and were characterized for haemolytic and enzymatic activity, and antagonism against Vibrio . Selected strains were included in the diet of juvenile tilapia and evaluated during a 134-day assay. The experiment was conducted with four treatments: (1) fish fed with commercial feed plus Dry Oil^®; (2) fish fed with commercial feed plus LAB; (3) fish with bacilli in water; (4) fish with a mixture of treatments 2 and 3. Tilapias in all treatments, including bacteria, grew significantly better than fish fed with commercial feed plus Dry Oil^® (control group). Survival was similar in all treatments. The physicochemical parameters of the culture system were maintained within the optimal ranges for the species, with the exception of temperature (19.9–24.82 °C). Animals fed diet supplemented with bacilli and LAB had good survival and the best growth performance, suggesting that bacteria are appropriate growth-stimulating additives in tilapia cultivation.  相似文献   

Effect of a Cell‐Wall‐Degrading Enzyme Complex on Starch Recovery and Steeping Requirements of Sorghum and Maize     

Sergio O. Serna‐Saldívar  Martha Mezo‐Villanueva 《Cereal Chemistry》2003,80(2):148-153

The effect of a commercial cell‐wall‐degrading enzyme (CWDE) complex on the steeping time and starch yields of white regular sorghum (RSOR) compared with yellow maize (YMZ) was determined. An in vitro wet‐milling method standardized to test dosages of 0–120 fungal β‐glucanase units (FBG)/100 mL indicated that starch yields were significantly higher for YMZ than RSOR and increased proportionally as enzyme dosage increased. A factorial experiment with a level of confidence of P < 0.05 was performed to study the effect of CWDE addition to coarsely ground grains for 4 hr after 20 or 44 hr of SO₂ steeping of whole grains. At both regular steep times, YMZ yielded significantly higher amounts of starch than RSOR. When steep times were compared, grains soaked for 48 hr produced 1.7% higher starch yields than counterparts treated for 24 hr. CWDE significantly increased starch yields and recoveries. Enzyme‐treated grains yielded 2.5% more starch than counterparts steeped regularly. For both grains, the best wet‐milling conditions to obtain the highest amount of starch were 48 hr of steeping and CWDE addition. Under these conditions, YMZ and RSOR yielded 66.9 and 66.6% starch, respectively. Starches obtained after the enzyme treatment at both steep times contained higher amounts of residual protein and ash compared with the untreated counterparts. Rapid viscoamylograph properties of YMZ and RSOR starches were not affected by the use of the CWDE nor the steep time. In comparison with RSOR starch, the YMZ starch initiated gelatinization at lower temperature, had less shear thinning and higher viscosity or setback at the end of cooling.  相似文献   

Stress response and lipid composition in shrimp Litopenaeus vannamei fed diets enriched with squid or scallop viscera meal     

Celene Navarro  Roberto Civera  Olivia Arjona  Crisalejandra Rivera‐Perez  Hugo Sergio García  Miguel ngel Hurtado‐Oliva  Elena Palacios 《Aquaculture Research》2020,51(4):1602-1622

We substituted 10% of fishmeal with scallop (Argopecten ventricosus) or squid (Dosidiscus gigas) by‐product meal in a feed for shrimp (Litopenaeus vannamei) growth assay that lasted 60 days and then shrimps were submitted to handling stress. Shrimp fed the control diet had smaller weight gain and lower recovery after stress. Prostaglandins in gills were affected by diet and stress, with significant differences in shrimp fed the control diet before and after the stress. Hydroperoxides were increased after stress, while isoprostanoids were higher in shrimp fed the control diet. The gene expression of Glutathione peroxidase and Catalase was increased on the stressed shrimp fed the scallop diet, with no differences among diets for Superoxide dismutase or Cyclooxygenase. Arachidonic acid in the phospholipid fraction of muscle was the only fatty acid affected by stress and diet. Cholesterol oxidation products were significantly higher in shrimp fed the scallop diet compared to shrimp fed the control diet before applying the stress. A PCA analysis grouped in one‐factor growth variables, as well as Superoxide dismutase, esterified astaxanthin and isoprostane, while another factor was determined by stress, prostaglandin and hydroperoxide levels in gills. The partial substitution of fishmeal with scallop of squid by‐product meals affected growth and stress differently, indicating shrimp that grew up more were not necessarily more tolerant to handling stress, which can have a strong repercussion in aquaculture, particularly during density control, recording of growth and harvest.  相似文献   

In vivo and in vitro protein digestibility and growth performance of animal and no‐conventional plant ingredients for river prawn Macrobrachium americanum (Caridea: Palaemonidae)     

Ana M. Parra‐Flores  Jesús T. Ponce‐Palafox  lvaro F Barreto‐Altamirano  Milton Spanopoulos‐Hernndez  Sergio G. Castillo‐Vargasmachuca  Gabriela Gaxiola  Hctor Esparza‐Leal  Apolinar Santamaría‐Miranda 《Aquaculture Research》2020,51(9):3652-3663

The objectives of this study were to evaluate the effects of non‐traditional plant and animal protein for river prawn M. americanum on in vivo versus in vitro digestibility in addition to growth performance. In this study, ten ingredients were used: coconut meal, jackfruit meal, soybean meal, poultry by‐product meal, squid meal and fish meal. In vivo studies were conducted using the zeolite marker method, whereas in vitro digestibility was determined by the pH‐stat method using river prawn hepatopancreas enzymes. According to the findings, river prawns digest animals more efficiently than plant ingredients, with squid and fish meal showing a tendency of higher values. Fish meal (53.66%), squid meal (48.52%) and jackfruit meal (42.21%) were found to have a digestibility greater than 40% in in vivo and in vitro methods, thus suggesting that they are the best ingredients used in this study. This also validates their inclusion in practical diets. The correlation of digestibility of in vivo and in vitro was low (R² = .6749). The highest daily weight gain was recorded in the diets containing jackfruit, coconut and squid. Given that the potential of no‐conventional plant ingredients available regionally was significantly higher, this underscores the need to conduct further research to validate their inclusion in practical diets.  相似文献   

Far-reaching blues: Long-distance migration of the invasive Atlantic blue crab     

Sergio Bedmar  Francisco J. Oficialdegui  Miguel Clavero 《水产资源保护:海洋与淡水生态系统》2024,34(4):e4136

Nitrogen requirements for deficit-irrigated bermudagrass (Cynodon spp.) fairways in South Florida     

Marco Schiavon  Travis W. Shaddox  Karen E. Williams  Sergio Gallo  P. Agustin Boeri  J. Bryan Unruh  Jason Kruse  Kevin Kenworthy 《Journal of Agronomy and Crop Science》2023,209(1):1-11

Several new bermudagrass cultivars are available and commonly used on golf course fairways. However, little is known about their cultural requirements or how these cultivars perform under lower inputs regimes. A 2-year study was conducted at University of Florida, Fort Lauderdale Research and Education Center, to assess performance of four hybrid bermudagrass [Cynodon dactylon L. Pers. X Cynodon transvaalensis (Burtt-Davy)] cultivars (‘Latitude 36’, ‘Tifway 419’, ‘TifGrand’ and ‘TifTuf’), and 2 common bermudagrass (Cynodon dactylon L. Pers.) cultivars (‘Bimini’ and ‘Celebration’) irrigated at either 50% or 80% reference evapotranspiration (ET_o) and fertilised at either 0, 146, 244, or 342 kg N ha⁻¹ year⁻¹. Plots were evaluated monthly for turfgrass quality, dark green colour index (DGCI), normalised difference vegetation index (NDVI), and Chlorophyll Index, and seasonally for N tissue content. Plots watered at 80% ET_o enhanced bermudagrass quality compared to 50% ET_o, DGCI and NDVI only in two months out of 24. Latitude 36 and Celebration were the top-rated cultivars, and their quality was not affected by no N fertilisation. Conversely, TifGrand, TifTuf and Tifway that received no N fertilisation resulted in insufficient quality during the second year of the study. Insufficient quality may be linked to reduced N metabolization compared to the highest rated cultivars. Results show that new cultivars such as Latitude 36 and Bimini could be maintained at sufficient quality levels with reduced water and N inputs in South Florida.  相似文献   

Soil legacy phosphorus after 10 years of annual dairy liquid manure application in a no-tillage system     

Lenir Fátima Gotz  Nerilde Favaretto  Gabriel Barth  Paulo Sergio Pavinato  Volnei Pauletti 《Soil Use and Management》2023,39(1):606-617

The benefits of manure as a source of nutrients for plants and to improve soil quality are well-known. Monitoring of manure application is needed if environmental issues are to be prevented. In particular, the availability and accumulation of phosphorus (P) has to be subject to rigorous monitoring. This study aims to both evaluate the efficacy of the resin method in extracting inorganic labile P in soils under the long-term application of dairy liquid manure (DLM), and verify the influence of DLM on the recovery of applied P and soil legacy P. To realize our objectives, two long-term field experiments were established under a no-tillage system with annual DLM application on sandy clay loam (sandy Oxisol) and clayey (clayey Oxisol) soils. Treatment consisted of DLM applications (0, 60, 120, 180 m³ ha⁻¹ year⁻¹), independent of mineral fertilizer. Soil samples were taken from the 0–5, 5–10 and 10–15 cm layers after 10 years from the beginning of the trial. A single extraction with resin underestimated inorganic labile P; however, successive extractions were able to take up 43% and 26% of the total P in sandy and clayey Oxisols, respectively, whereas in a single extraction the take-up was 17% and 8% from the same soils, respectively. The resin method was more effective in extracting P from the sandy Oxisol. Thus, when interpreting soil P contents for fertilizer planning, the soil texture should be taken into account. DLM application decreased P recovered from applied P, ranging from 54% to 83% (sandy), and 43% to 67% (clayey), and substantially increased soil legacy P.  相似文献