Effects of graded levels of medium chain triglycerides and cysteine on growth, digestive processes and nutrient utilization in sea water reared Atlantic salmon (Salmo salar, L.) under ad libitum feeding regime

Fifteen experimental diets with five levels of medium chain triglycerides (MCT) (0, 39, 78, 117 and 156 g kg^?1) and three levels of cysteine supplementations (0.0, 2.5 and 5.0 g kg^?1) were fed ad libitum to Atlantic salmon (mean weight at start 846 g) in sea water for 71 days. Nutrient digestibilities and protein retention improved significantly with increasing dietary MCT level following simple linear regression models. Positive effects were also observed on proteolytic enzyme activities in chyme of the pyloric region with peak value around 117 g kg^?1 MCT. However, strong inverse relationships were observed between MCT level and feed intake, growth, body lipid and energy retention, and these effects accelerated with increasing MCT level. Also chyme dry matter decreased with increasing MCT level which also seemed to stimulate pancreatic and bile secretion. MCT did not significantly affect condition factor, dress out percentage, relative liver size or pH in gastrointestinal contents. The only significant effects of dietary cysteine supplementation were increased enzyme activities in chyme of the pyloric region with peak values for the intermediate cysteine level. The results elucidate the importance of diet composition for digestive functions, production efficiency and composition quality.     

Use of mineral element content of potato petioles for predicting yield potential

Six potato clones (Kennebec, Norchip, Norland, Red Pontiac, Russet Burbank, and M6664) were grown in a split-plot designed experiment to study the relationship of tuber yield and the mineral element content of petioles, both measured at 14 day intervals during the growing season. Seasonal trends in the N, P, K, and Mg content in petioles were highly intercorrelated. Concentrations of N, P, and K decreased with time, while Mg increased. Clones differed in the rate of change in these elements during growth. Trends in N, P, K and Mg content in petioles were highly correlated with tuber bulking. Change in N, P, K, and Mg concentrations are hypothesized to be a function of the sink strength of developing tubers. For another set of potato clones grown in a replicated yield trial, the change in petiolar K content with time was the “best” variable associated with final tuber yields. A regression model [Model II: Y(cwt/A)=200.6223-1887.0150 (b_k)] is given for predicting the yield potential of 18 clones. Given the slope of the petiolar K concentration (b_k) during growth, this model identified 9 of the 10 top yielding clones. Factors affecting the reliability of the model are discussed.     

Dakota rose: A bright red tablestock potato cultivar that retains its skin color in storage

‘Dakota Rose’ is a medium-maturing, white-fleshed, red-skinned cultivar that retains its bright red color in storage. Tubers have very smooth skin with an oblong shape. Yields are equivalent, or superior, to ‘Red Norland’, but lower than ‘Red Pontiac’, a late-maturing cultivar. Dakota Rose produces a high percentage of U.S. No. 1 tubers and few oversized tubers. Sensory evaluation scores for baked, boiled, and microwaved potatoes are similar to Red Norland and Red Pontiac, standard red tablestock cultivars. The specific gravity averaged about 1.067 across irrigated and non-irrigated sites, a typical value for a red tablestock cultivar. Adequate skin set for handling has often been difficult to achieve; application of nitrogen early in the growing season, coupled with chemical vinekill 3 weeks prior to harvest aids in minimizing the problem. Dakota Rose was released by the North Dakota Agricultural Experiment Station on 17 November 2000.     

Sangre: An oval,high quality red potato

Sangre is a medium maturing, high quality, fresh market red potato adapted to irrigated areas of the West. Tubers are deep red, oval to oblong, shallow-eyed and have a thick skin. Baking and boiling quality is excellent. Sangre is slow emerging and produces a medium size vine. It is susceptible to early and late blights, Verticillium, moderately susceptible to dry rot and bacterial soft rot, moderately resistant to early blight tuber rot, resistant to leafroll net necrosis, and rarely exhibits hollow heart, internal discoloration or blackspot.     

The influence of potassium fertilizer application on tuber yield and mineral element content of potato petioles during the growing season

Potassium was applied at rates equivalent to 0, 135, and 250 pounds per acre (0, 151, 180 kg K/ha) to study the effect of soil applied K on tuber yields and concentration of mineral elements in the petioles of potato plants during growth both measured at 14 day intervals. Petioles were analyzed for N, P, K, Ca, Fe, Mg, Zn, Cu, Al, Mn, and B. Seasonal trends in petiolar K content were highly correlated with tuber bulking regardless of rate of K application. Increasing K application rates generally increased petiolar levels of K and Zn (early in the season) and decreased the levels of N, Mg, Ca, Zn (late in the season), Al, Fe, Cu, and B in the petioles. Concentrations of P and Mn were unaffected by K applications. Seasonal trends in the mineral element content of petioles were not influenced by K. Results indicate that a prediction model for tuber yield based upon trends in the K content of petioles is valid under differing soil levels of K.     

Potato clone variation in blackspot and soft rot susceptibility,redox potential,ascorbic acid,dry matter and potassium

Tubers of 11 potato clones were compared for susceptibility to blackspot and soft rot, redox potential, ascorbic acid, dry matter, and potassium content. Evaluations were made before and after 6 mo storage at 3.9C. Clonal behavior was generally consistent over 2 yr. Significant differences occurred among clones for each factor except redox potential. Blackspot and soft rot were positively correlated in 5 of 8 comparisons. Neither blackspot nor soft rot was correlated with ascorbic acid or redox potential. Blackspot was positively correlated with dry matter in the fall but not after storage and was negatively correlated with potassium. Soft rot evaluated in air or air plus 8% CO₂ was positively correlated with dry matter in only 2 of 8 comparisons. Soft rot susceptibility did not increase with storage when inoculated discs were incubated in air but did increase when the discs were incubated in air plus 8% CO₂. Ascorbic acid was negatively correlated with redox potential only before storage and decreased to varying degrees in all clones during storage.     

Individual and combined effects of pre- and post-anthesis temperature on protein composition of two malting barley cultivars

The present study has investigated the individual and combined influence of pre- and post-anthesis temperatures and cultivars on the protein composition in barley grains. Two barley cultivars were grown in soil and hydroponic systems in daylight chambers with different pre- and post-anthesis temperatures. Size exclusion (SE)-HPLC was used to evaluate the protein composition in mature barley grains. The results showed that individual and interactive effects of pre- and post-anthesis temperatures and cultivar variations influenced protein composition in the barley grains. Pre-anthesis temperature greatly affected the amounts of total sodium dodecyl sulphate (SDS) extractable proteins (TOTE) and explained 30% of the variation in TOTE. The barley cultivars accounted for 20% of the variation in TOTE. Variation in malting barley cultivars was found to influence the SDS extractable small monomers (41% of the variation). Percentage of SDS un-extractable polymeric proteins in total amount of polymeric proteins (%UPP) was governed by post-anthesis temperature, accounting for 11% of the variation and cultivar differences accounted for 7% of the variation. Thus, the climatic conditions during the specific growing period and a choice of cultivars played a major role in determining the protein composition and ultimately the malting quality of spring barley.     

Effect of Harvest Date on PI2, Total Protein, TGA Content and Tuber Performance in Potato

Proteinase inhibitor 2 (PI2), isolated from potatoes is associated with the release of cholecystokinin (CCK), a satiety factor in humans. PI2 is the active ingredient of Slendesta® Potato Extract. The effect of harvest date on the levels of proteinase inhibitor 2 (PI2), total protein content and total glycoalkaloids (TGA) was studied in two potato (Solanum tuberosum L.) clonal lines. In addition, tuber specific gravity, tuber yield, and tuber size distribution were measured in response to harvest date. The two potato clonal lines designated as KI-PSt0018 and KI-PSt0034 were planted in a randomized complete block design with four replicates. Tubers were harvested at four different dates during the growing season; 4 weeks and 2 weeks to vine-kill; at vine-kill; and 2 weeks post vine-kill. Sample tubers from these four harvest dates and from 2 months of storage, post vine-kill stage were analyzed for PI2, total protein and TGA. Harvesting at different dates had a significant influence on most of the traits studied in both clonal lines. The two clonal lines responded differently to different harvest dates for all traits except PI2 and specific gravity. PI2 levels increased with maturity with the highest levels observed at full maturity in both clonal lines. The protein levels did not show any specific trend in either clonal line. TGA levels increased gradually in small increments with maturity in KI-PSt0018 but did not have a clear pattern in KI-PSt0034. Tuber yield and size increased with maturity of the crop in both clonal lines. Higher tuber yields were seen during final vine-kill and 2 weeks post vine-kill compared to the earlier stages of harvest in both clonal lines. Tuber specific gravity declined when tubers were left in the ground for 14 to 21 days after vine-kill in both clonal lines. This study indicated harvest of potato prior to vine-kill is not beneficial for the extraction of PI2 for use as functional food or dietary supplement ingredient.     

Towards a sustainable fisheries policy in Europe

The reform of the European Common Fisheries Policy (CFP) in 2013 decides whether the European fisheries can be put on a sustainable course in the next 10 years. The CFP reform must halt overexploitation of fish resources and stop harm to the marine environment by fishing activities. The European Commission published a reform proposal just recently. This proposal is already an important first step in the right direction, but is under threat of being watered down by the Fisheries Council. Necessary improvements of the current CFP include among others a binding definition of a sustainable stock management, a discard ban for all fish species, transferable fishing concessions and a cessation of all aid for building new vessels. These modifications pave the way for placing micromanagement in the hands of regions and fisheries so as to foster self‐responsibility among fishers and give greater consideration to regional circumstances.