Effect of protein and lipid levels in diets for female red claw crayfish Cherax quadricarinatus on quality of offspring (juvenile), with emphasis on growth performance,biochemical composition and stress resistance to low oxygen,high ammonia and salinity     

H. Rodríguez‐González  A. Hernández‐Llamas  M. García‐Ulloa  I.S. Racotta  M. Montoya‐Mejía  H. Villarreal 《Aquaculture Nutrition》2014,20(5):557-565

This study measures the effect of protein and lipid levels in broodstock diet on the quality of juvenile Cherax quadricarinatus. Diets with different contents of crude protein (180, 250, 310, 370 g kg^?1) and lipids (30 and 70 g kg^?1) were offered to female crayfish. Juveniles were used to assess initial weight (IW), biochemical composition (BC) and survival to stress tests (ST). After 50 days, growth was estimated. No significant effects of broodstock diet on IW and BC of juveniles were detected. Protein content (PC) significantly influenced growth (P < 0.05), with an optimum level of 250 g kg^?1, representing a weight gain of 1.17 g (98.08% body weight). PC significantly influenced survival of juveniles exposed to ST (P < 0.05). Results from fitting dose–response models indicated that maximum survival was obtained with PC above 261, 258 and 312 g kg^?1 for hypoxia, salinity, ammonia tests. No significant effect of dietary lipid level was observed on growth and survival to ST, except for greater survival to ammonia ST at lipid content of 70 g kg^?1. We recommend feed with PC of 260 g kg^?1 to simultaneously enhance growth and quality of juveniles.  相似文献   

Thermal Characterization of Alkali Treated Kenaf Fibers and Kenaf-Epoxy Composites     

Levi Gardner  Troy Munro  Ezekiel Villarreal  Kurt Harris  Thomas Fronk  Heng Ban 《Fibers and Polymers》2018,19(2):393-402

Chemical treatment of natural fibers is a well-defined means of mechanical property improvement in natural fiberreinforced composites. An understanding of mechanical and thermal properties in these media is essential for evaluating heat transfer, thermal degradation, and overall performance of these composites over their product lifetime. However, very little information is available illustrating the effect of such treatment on the thermal properties of kenaf composites. Also, no study to date has reported the thermal conductivity of individual kenaf fibers. This study reports the effects of fiber treatment (in 6 % NaOH) on thermal transport in unidirectionally oriented kenaf-epoxy composites and individual kenaf fibers. The effective thermal conductivities and thermal diffusivities of chemically treated fiber composites show a general increase over untreated fiber composites (0.210 to 0.232 W/m/K at 28 °C, 0.206 to 0.234 W/m/K at 200 °C). This improvement may be attributed to improved interfacial contact between the fibers and epoxy matrix shown in microstructural images after chemical treatment. The thermal conductivity of individual fibers was evaluated at room temperature using two techniques. Results from both techniques showed slight increases after chemical treatment (0.58±0.53 to 1.0±0.13 W/m/K and 1.2±0.54 to 1.6±0.28 W/m/K) but lacked statistical significance. Any improvement in surface crystallinity after chemical treatment does not appear to affect overall fiber thermal conductivity. A better understanding of thermal transport in kenaf fibers and composites enables better estimation of the performance of these composites in different applications. Moreover, the thermal conductivities of individual fibers are useful in understanding the fiber’s contribution to conduction in different fiber reinforcement configurations.  相似文献   

Deposition of litter and nutrients in leaves and twigs in different plant communities of northeastern Mexico     

Humberto González-Rodríguez  Roque Gonzalo Ramírez-Lozano  Israel Cantú-Silva  Marco Vinicio Gómez-Meza  Eduardo Estrada-Castillón  José Ramón Arévalo 《林业研究》2018,29(5):1307-1314

Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The objective of this research was to assess litterfall production,the potential deposition of macro and micronutrients through leaf and twig fall as well as macronutrient—use efficiency in three forest ecosystems at different altitudes: a pine forest mixed with deciduous species(S1); a Quercus spp.forest(S2); and,a Tamaulipan thornscrub forest(S3).Total annual litterfall deposition was 594,742 and 533 g m~(-2) for S1,S2 and S3.Leaf litter was higher (68%) than twigs(18%),reproductive structures(8%) or miscellaneous material(6%).Micronutrient leaf deposition was higher for Fe followed by Mn,Zn and Cu.Macronutrient leaf deposition was higher for Ca followed by K,Mg and P.Even though P deposition in leaves and twigs was lower than other macronutrients,its nutrient use efficiency was higher than Ca,Mg or K.Altitude and species composition determine litter and nutrient deposition,with higher values at mid-altitudes(550 m).Altitude is an important factor to consider when analyzing litter production as well as nutrient deposition as shown in this study.Litter production and nutrient deposition are expected to change in a scenario of global warming.  相似文献   

Comparative analysis of texture descriptors in maize fields with plants,soil and object discrimination     

Yerania Campos  Humberto Sossa  Gonzalo Pajares 《Precision Agriculture》2017,18(5):717-735

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In vitro antifungal activity of extracts of Mexican Chihuahuan Desert plants against postharvest fruit fungi     

D. Jasso de Rodríguez  R. Rodríguez GarcíaF.D. Hernández Castillo  C.N. Aguilar GonzálezA. Sáenz Galindo  J.A. Villarreal QuintanillaL.E. Moreno Zuccolotto 《Industrial Crops and Products》2011,34(1):960-966

Chemical fungicides have been intensively used in the control of diseases in fruits in postharvest conditions; nevertheless these actions have developed resistance in the phytopathogens, have contaminated the atmosphere, and have affected people's health through residual toxic compounds present in the food for human consumption. The objective of this study was to evaluate the in vitro inhibiting activity of extracts of Lippia graveolens Kunth, Agave lechuguilla Torr. Yucca carnerosana (Trel.) Mc Kelvey and Yucca filifera Chaub., against Rhizopus stolonifer, Colletotricum gloesporoides and Penicillium digitatum the postharvest fungi that causes diseases in fruits of commercial interest. The plants were collected in the neighborhood of the cities of Saltillo and Torreon in the Southern Region of the State of Coahuila in the semi-arid zones of the North of Mexico. The extracts of the plants were obtained with ethanol and hexane as solvents, and the resin was separated of solvent in a rotary evaporator. The fungi were isolated of apple, mango and orange fruits and were then seeded in Potato-Dextrose-Agar medium; the bioassays were inoculated with fungi and developed in Petri dishes. The evaluated variables were: Inhibition of mycelial growth, and Inhibition of the number of spores. For the analysis of the information a completely randomized experimental design in factorial arrangement was used. The results showed that the ethanolic extracts of L. graveolens at 500 μl L⁻¹ presented a fungicide effect of 100% against R. stolonifer, Y. filifera at 4000 μl L⁻¹ inhibited 100% the pathogen. The hexanic extracts of L. graveolens presented an inhibition of 100% at 500 μl L⁻¹. A. lechuguilla inhibited the pathogen in 100% at 3000 μl L⁻¹. The extract of L. graveolens, A. lechugilla, Y. carnerosana and Y. filifera showed its inhibiting activity in different percentages against the development of R. stolonifer, Colletotrichum gloeosporioides, and P. digitatum. This is the first scientific report that shows anti-fungal activity of ethanolic and hexanic extracts of L. graveolens, A. lechuguilla, Y. carnerosana, and Y. filifera against R. stolonifer, C. gloesporoides, and P. digitatum.  相似文献   

Bioassay-guided isolation of an anti-ulcer chromene from Eupatorium aschenbornianum: Role of nitric oxide,prostaglandins and sulfydryls     

María Elena Sánchez-Mendoza  Benito Reyes-Trejo  Paula Sánchez-Gómez  Juan Rodríguez-Silverio  Carlos Castillo-Henkel  Humberto Cervantes-Cuevas  Jesús Arrieta 《Fitoterapia》2010

Eupatorium aschenbornianum is considered useful in the treatment of gastric ulcer. In the current study the validity of this practice was tested by using the experimental model of an ethanol induced gastric ulcer in rats. The results show that E. aschenbornianum had gastroprotective activity, that the hexane extract had the highest protective activity (85.65 ± 4.76%), and that encecanescin isolated from this extract was the main active gastroprotective agent. The effect elicited by encecanescin was attenuated by N^G-nitro-l-arginine methyl ester, N-ethylmaleimide and indomethacin, which suggests that NO, prostaglandins and sulfydryl groups are involved in the mechanisms of gastroprotective action.  相似文献   

Activity of trypsin from Litopenaeus vannamei     

Juan Carlos Sainz Hernndez  Julio Humberto Cordova Murueta 《Aquaculture (Amsterdam, Netherlands)》2009,290(3-4):190-195

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A comparison of circle hook and J hook performance in a western equatorial Atlantic Ocean pelagic longline fishery     

J.C. Pacheco  D.W. Kerstetter  F.H. Hazin  Humberto Hazin  R.S.S.L. Segundo  J.E. Graves  F. Carvalho  P.E. Travassos 《Fisheries Research》2011,107(1-3):39-45

Catch composition, catch rates, hooking location, and status at release at haulback were monitored during 81 experimental sets (launches and hauling fishing per day) in a commercial pelagic longline fishery targeting tuna in the equatorial South Atlantic Ocean. Circle hooks (size 18/0, 0° offset) and J-style hooks (size 9/0, 10° offset) with squid baits were deployed in an alternating fashion. The catch composition was not significantly different for most species between the two types of hooks, except for bigeye tuna, which showed a significantly higher proportion of catches on the circle hook (p ? 0.001) and for sailfish, pelagic stingray, and leatherback sea turtle, which had higher catch rates on the J-style hook (p = 0.018, p ? 0.001, and p = 0.044, respectively). Bigeye and yellowfin tuna showed significantly higher rates of survival at the time of gear retrieval with circle hooks, and circle hooks hooked bigeye tuna, yellowfin tuna, swordfish, and sailfish significantly more often externally than internally. Our results suggest that the use of size 18/0, 0° offset circle hooks in the equatorial pelagic longline fishery may increase the survival of bycatch species at the time of gear retrieval with minimal effects on the catches of target species.  相似文献   

Effect of dietary protein‐to‐energy ratio on reproduction in female redclaw crayfish Cherax quadricarinatus     

Hervey Rodríguez‐González  Humberto Villarreal  Alfredo Hernández‐Llamas  Manuel García‐Ulloa  Celia Vázquez‐Boucard  Vania Serrano‐Pinto 《Aquaculture Research》2011,42(12):1840-1847

The effect of eight diets with different protein‐to‐energy ratios (P–E ratio=10, 11, 14, 16, 18, 20, 22, 24 mg kJ^?1) on reproduction of female redclaw crayfish Cherax quadricarinatus was tested under laboratory conditions. After 75 days, there was a significant effect of the P–E ratio on final weight, spawning females and the number of juveniles per female. Using the broken‐line and quadratic equations, optimal values for the P–E ratio were: 16.0, 17.1 and 16.0 mg kJ^?1. The P–E ratio significantly affected protein and carbohydrate content and energy in the hepatopancreas. The broken‐line model indicated that the respective recommended values of the P–E ratio for these parameters were: 21.8, 16.7 and 18.6 mg kJ^?1. The concentration of carbohydrates and energy in muscle tended to significantly diminish as the P–E ratio increased. From broken‐line regression analysis, the recommended P–E ratio was 16.6 and 20.2 mg kJ^?1 respectively. No significant differences were found in survival, fecundity, vitellin content in eggs, protein and lipid content in muscle and lipids in the hepatopancreas. We concluded that, overall, a P–E ratio of 18±2 mg kJ^?1 is optimal for reproductive activity of female redclaw crayfish.  相似文献   

Negative Impact on the Aquatic Ecosystems of the State of Morelos, Mexico from Introduced Aquarium and Other Commercial Fish     

Topiltzin Contreras-MacBeath  Humberto Mejia Mojica  Roberto Carrillo Wilson 《Aquarium Sciences and Conservation》1998,2(2):67-78

Of the 22 fish species presently inhabiting the waters of the state of Morelos, México, more than half (64%) have been introduced, mainly for fisheries and ornamental aquaculture purposes. Even though there are other significant problems such as pollution, eutrophication and drought, we found that fish introductions have caused the worst ecological impacts. These problems stem from a general lack of knowledge regarding the characteristics, importance and appropriate use and management of aquatic resources. Conservational actions are proposed.  相似文献