Effect of selenium supplementation and source on the selenium status of horses

This study was conducted to determine the effect of Se supplementation and source on the Se status of horses. Eighteen 18-mo-old nonexercised horses were randomly assigned within sex to 1 of 3 treatments: 1) control (CTRL, no supplemental Se, 0.15 mg of Se/kg of total diet DM); 2) inorganic Se (INORG, CTRL + 0.45 mg of Se/kg of total diet DM from NaSeO3); or organic Se [ORG, CTRL + 0.45 mg of Se/kg of total diet DM from zinc-L-selenomethionine (Availa Se, Zinpro, Corp., Eden Prairie, MN)]. Horses were acclimated to the CTRL diet (7.1 kg of DM alfalfa hay and 1.2 kg of DM concentrate per horse daily) for 28 d. After the acclimation period, the appropriate treatment was top-dressed on the individually fed concentrate for 56 d. Jugular venous blood samples were collected on d 0, 28, and 56. Middle gluteal muscle biopsies were collected on d 0 and 56. Muscle and plasma were analyzed for Se concentrations. Glutathione peroxidase activity was measured in muscle (M GPx-1), plasma (P GPx-3), and red blood cells (RBC GPx-1). Data were analyzed as a repeated measures design. Mean plasma Se concentration on d 28 and 56 was greater (P < 0.05) for Se-supplemented horses compared with CTRL horses, and tended (P < 0.1) to be greater in ORG vs. INORG on d 28. Mean muscle Se concentration and P GPx-3 activities increased (P < 0.05) from d 0 to 56 but were not affected by treatment. Mean RBC GPx-1 activity tended to be greater (P < 0.1) in ORG than INORG or CTRL horses on d 28, and tended to be greater (P < 0.1) for INORG compared with ORG horses on d 56. Mean RBC GPx-1 activity of INORG and ORG horses was not different from that of CTRL on d 56. Mean M GPx-1 activity decreased (P < 0.01) from d 0 to 56. In conclusion, zinc-L-selenomethionine was more effective than NaSeO3 at increasing plasma Se concentration from d 0 to 28; however, both supplemental Se sources had a similar effect by d 56. No difference in Se status due to Se supplementation or source could be detected over a 56-d supplementation period by monitoring middle gluteal muscle Se, M GPx-1, or P GPx-3. Results for RBC GPx-1 also were inconclusive relative to the effect of Se supplementation and source.     

Certain physiochemical properties of uterine tubal fluid, follicular fluid, and blood plasma in the mare.

Uterine tubal fluids were collected twice a day from mares for 5 consecutive estrous cycles between March 15 and September 1. Follicular fluids were aspirated from the follicles of exteriorized ovaries of 3 mares between days 2 and 5 of estrus. Uterine tubal fluid and follicular fluid were analyzed for osmolarity, dry matter, total lipids, total free fatty acids, glucose, fructose, and lactic acid. Blood samples were collected (jugular venipuncture) throughout the estrous cycle, and the same physical and biochemical analyses were made on blood plasma. A difference (P less than 0.01) was found for osmolarity between uterine tubal fluids collected during estrus and those collected during anestrus. The osmolarity of uterine tubal fluid during anestrus was greater than that of blood plasma; follicular fluid was similar in osmolarity to blood plasma. The dry matter in blood plasma was greater (P less than 0.01) than that in either uterine tubal fluid or follicular fluid. Cyclic variations in dry matter content were not observed in uterine tubal fluid. Total lipids in blood plasma and follicular were greater (P less than 0.01) than those in uterine tubal bluid. The concentration of total lipid in uterine tubal fluid was similar during estrus and anestrus. Myristic acid (C14:0) in blood plasma and myristoleic acid (C14:1) in uterine tubal fluid were the only free fatty acids that had cyclic variation. The fatty acids in the greatest concentration in uterine tubal fluid and blood plasma were palmitic acid (C16:0) and linoleic acid (C18:2). Concentrations of linoleic acid and stearic acid (C18:0) were greater (P less 0.01) in follicular fluid than in uterine tubal fluid or blood plasma. Only trace amounts of glucose were detected in uterine tubal fluid, whereas a considerable amount of glucose was found in follicular fluid. Fructose was not detected in any of the fluids. Lactic acid concentrations did not differ between estrus and anestrus. Lactic acid concentration was significantly greater (P less than 0.01) in uterine tubal fluids and follicular fluids than in blood plasma.     

Analysis of Catfish Pricing and Market Dynamics: The Role of Imported Catfish

The producer price of catfish is becoming relatively unstable compared to the trend in previous years, necessitating the need for a complete analysis of catfish pricing and market dynamics. An understanding of the price determination mechanisms in the catfish market and the relationships between producer price, domestic processed price, and import price are important because price variability can result in significant financial losses to the domestic catfish industry. This study used a cointegration procedure to examine the long-run relationships between domestic prices of catfish and imported price. Results from unit root and cointegration tests suggest that there is a long-run equilibrium relationship between pairs of these prices. Results from Granger causality tests and error-correction model estimations suggest that the market for domestic frozen fillets plays a significant role in the price determination of imported catfish. A similar relationship is found between producer price and frozen fillet price. Some significant measures that were estimated include a frozen fillet-producer long-run price transmission elasticity of 0.162, a frozen fillet-imported fillet long-run price transmission elasticity of 3.56, and a producer-frozen fillet short-run price transmission elasticity of 0.322. High levels of fillet prices appear to have influenced the level of catfish imports. As long as distributors and restauranteurs do not see a basis for paying a premium for U.S. catfish products, they will continue to purchase the lower-priced imported catfish and consequently imports will continue to increase.     

Response of weed emergence to rate of Vicia villosa Roth and Secale cereale L. residue

Vicia villosa Roth (hairy vetch) or Secale cereale L. (rye) residue at 2 to 4 times the natural field rate reduced seedling emergence of a wide variety of weed species. However, the natural rate of residue was insufficient for control of most weed species. The form of the response of weed emergence to increasing rates of residue varied among species: emergence of some species showed a monotonic decline in response to increasing rates of residue whereas emergence of others increased at low rates before declining at higher rates. In addition to reducing number of seedlings, high rates of residue delayed the date of emergence. Seed size was generally not a good indicator of a species' ability to emerge through residue, although one very large seeded weed, Abutilon theophrasti. was especially insensitive to residue. V. villosa and 5. cereale did not differ greatly in their effect on weeds early in the growing season, but V. villosa decomposed more rapidly and allowed greater emergence later in the season. Effet de résidus de Vicia villosa Roth et de Secale cereale L. sur la levée des mauvaises herbes Des résidus de Vicia villosa Roth (Vesce velue) et de Secale cereale L. (seigle) à 2–4 fois la quan-tité normale réduisaient la levée d'un large spectre de mauvaises herbes. Cependant la quantité normale de résidus était insuffisante pour lutter contre la plupart d'entre elles. La réponse de la levée des mauvaises herbes à des quantités crois-santes de rVsidus différait selon les espèces. Pour certaines, la levée subissait un déclin monotone; pour d'autres, elle augmentait en présence de faible quantités de reésidus puis décroissait pour des quantités plus importantes. Ces dernières réduisaient la levée et la retardaient également. La taille des graines n'était généralement pas un bon indicateur de la capacité des espèces à lever au travers des résidus, bien qu'une trèAs grosse grains, Abutilon theophrasti Medic., était particu-lièrement insensible aux résidus. V. villosa et 5. cereale ne différaient pas beaucoup dans leur effet sur les mauvaises herbes en début de saison, mais V. villosa se décomposait plus rapidement et permettait des levees plus importantes en fin de saison. Wirkung von Emterückständen von Vicia villosa Roth und Secale cereale L. aufdie Keimung von Unkräutern Durch 2- bis 4 fache Ernteräckstände der Be-haarten Wicke (Vicia villosa) und des Roggens (Secale cereale) wurde die Keimung einer großen Zahl von Unkrautarten herabgesetzt. Normale Ernterückstandsmengen behinderten jedoch die Keimung nur unzureichen. Die Art und Weise der Reaktion der Keimung auf höhere Riick-stände war von Art zu Art verschieden: Die Keimung einiger Arten nahm mit zunehmender Menge an Ernterückständen gleichmäßig ab, während sie bei anderen bei niedrigen Mengen anstieg, urn dann bei höheren Mengen abzunehmen. Zusätzlich zur Verringerung der Keimpflanzendichte wurde bei hohen Rück-standsmengen die Keimung verzögert. Die Samengröße war im allgemeinen kein guter Indikator für die Fähigkeit einer Art, durch das Rückstandsmaterial zu keimen, obwohl eine Art mit großen Samen, Abutilon theophrasti, gegenüber diesen Rückständen besonders unempfindlich war. Die Rückstände der beiden Kulturpflanzen zeigten zu Beginn der Vegetationsperiode keine großen Wirkungsunterschiede, aber die Rückstände von Vicia villosa zerfielen schneller und ließen später eine stärkere Keimung zu.     

苜蓿蓟马抗性与生理活性相关性研究(英文)

[Objective] The experiment explored of resistance of different Medicago sativa through synthetic variations of all physiological indexes and the correlation analysis between physiological activity and damage degree after thrips damage. [Method] According to studying physiological activity (POD activity, SOD activity, PPO activity, PAL activity, MDA content and free proline content) of alfalfa in alfalfa resistance to different number of thrips, the correlation between physiological activity and resistance was investigated. [Result] It was shown that there were negative correlations among POD, SOD, PPO, PAL, MDA, free praline and the number of thrips, and there were negative correlations among POD, SOD, PPO, PAL, MDA, free praline and CAT. The content changes of POD,SOD,PPO,CAT,MDA and free proline in high resistant alfalfa were slow and PAL was quick and the activities of PPO,PAL,CAT were high, and the activities of POD、SOD were low. [Conclusion] The research provided theoretical basis and materials for identifying resistance varieties of alfalfa to thrip.     

Glutenin Macropolymer in Salted and Alkaline Noodle Doughs

An attempt was made to understand the physicochemical attributes that are the basis of physical differences between alkaline and salted noodle doughs. Flour and dough properties of one soft and three hard‐grained wheat cultivars were observed. Doughs were made with either sodium chloride or sodium carbonate. Each formulation variant was tested at both high and low water additions. Samples for glutenin macropolymer (GMP) isolation were taken at selected noodle dough processing stages. When a 1.67% w/v Na₂CO₃ solution was used for mixograph testing, dough characteristics were radically altered and differences between cultivars were masked. In lubricated squeezing flow (LSF) testing, hard wheat noodle doughs had significantly (P < 0.01) longer relaxation times and higher % residual force values than soft wheat doughs in both the salted and alkaline variants. LSF maximum force and biaxial viscosity were significantly higher in alkaline doughs than salted. GMP extracted from alkaline doughs was gummy and sticky, and was more opaque than GMP from salted doughs. GMP weight decreased sequentially when extracted from samples taken in the active phase (mix, compound, sheet) of noodle dough processing and decreased more in alkaline doughs. GMP weight increased more after 24 hr of dough rest in salted doughs. GMP gel strength was noticeably higher in GMP extracted from alkaline doughs. After dough resting, alkaline GMP gel strength significantly increased, whereas it decreased in GMP from salted doughs, suggesting a role for GMP in the increased stiffness of alkaline noodle doughs.     

The evolution of farm management,production efficiencies,and current challenges to catfish production in the United States

Abstract

The catfish industry is the most successful aquaculture business in the US. The development and growth of the catfish industry has resulted in complex fish farm businesses that require intensive management. Technological innovations have resulted in increased yields (land use efficiency). However, in more recent years, productivity gains have not kept pace with the rate of increase in input costs. Increasing intensification of catfish production over time has been accompanied by increased use of debt capital that results in higher levels of financial risk. While still a profitable activity, real profit margins have declined as financial risk has increased. New technologies will likely continue to increase productivity over time. Market‐oriented agribusiness approaches to catfish marketing are likely to become the norm. The challenge for the catfish industry is to coordinate adoption of new higher‐cost technologies with demand increasing market development to sustain farm price levels.     

Potential restaurant markets for farm‐raised tilapia in Nicaragua

Abstract

This study assessed the potential to increase sales of farm‐raised tilapia through domestic restaurants in Nicaragua. Direct personal interviews were conducted with 118 restaurant managers. Information was collected on tilapia and other seafood sales, restaurant and market characteristics, attitudes towards tilapia characteristics, and willingness to add tilapia to the menu. The results from logit analyses suggest that the most promising restaurant markets for tilapia are older restaurants that offered a variety of food and those that served steaks. Larger restaurants that considered tilapia to be a high‐quality product and that offered “ceviche” (fish marinated in lime juice) on the menu were those that tended to sell tilapia. Tilapia farmers and processors in Nicaragua will need to guarantee and ensure the flavor, quality, and safety of their product, and promote these attributes.     

FACTORS THAT INFLUENCE FREQUENCY OF PURCHASE OF CATFISH BY U.S. HOUSEHOLDS IN SELECTED CITIES

Increased understanding of the factors that influence the frequency of purchase of catfish (Ictalurus punctatus) by U.S. households would provide guidance for catfish marketing programs. A household survey was conducted to analyze consumer preferences and consumption trends of U.S. farm-raised catfish in Birmingham, Memphis, Chicago, Jackson (MS), New Orleans, Baton Rouge, Little Rock, Oklahoma City, Dallas, Houston, and San Antonio. An ordered probit model was developed to examine the variables influencing frequency of catfish purchase. Household respondents in all cities except Jackson, New Orleans, Oklahoma City, and San Antonio were found to be more frequent buyers of catfish products. Respondents who preferred fresh catfish had a greater likelihood of frequent catfish purchase while buyers of frozen catfish were less likely to purchase catfish frequently. Method of preparation and serving had no influence on catfish purchase frequency. Buyers purchasing from supermarket outlets had a higher probability of being more frequent buyers of catfish products than those who purchase from other market outlets. Product origin labels and vacuum-sealed packaging influenced the frequency of catfish purchase. Caucasians and African Americans were found to be more frequent buyers of catfish products while Hispanics were found to be significantly less frequent buyers of catfish products. Married couples had a greater likelihood of purchasing catfish more frequently than unmarried couples. Age of the respondents as well as number of household members had no significant effect on frequency of catfish purchase. The results from this study support the importance of country of origin labeling, supplying high-quality fresh products, and alternative packaging to enhance sales of U.S. farm-raised catfish in supermarkets.