Effect of Different Proportions of Wolffia on Growth of Procambarus clarkia in Two Community Scales

[Objective] This study aimed to examine the effect of different proportions of Wolffia on the growth of Procambarus clarkia in 2 kinds of community scales. [Method] Six proportions of baits mixed by watermeal and commercial feed (0, 20%, 40%, 60%, 80%, and 100%) were designed to feed the Procambarus clarkia juveniles in 2 community scales to research the growth situation of the crayfish in different mixed baits. The growth differences between the minimal community and the larger community of crayfish in the same proportion of Wolffia were compared. [Result] The growth situations of crayfish in the 2 community scales at different proportions of watermeal were as follows: the body length was the longest in 60% watermeal group, and shortest in the pure watermeal group; the regularity was the best in the 20% watermeal group; no matter the minimal community or the larger community, there was no significant difference in the survival rate between different watermeal proportions. The growth situations of crayfish in the 2 community scales at specific proportion of watermeal were: the average body length of the minimal community was significantly greater than the larger community, and the survival rate also greater than the latter one, but the difference was not significant. [Conclusion] Considering all kinds of index such as growth, survival rate, regularity, the appropriate proportion of the baits mixed by watermeal and commercial feed is 40% to 60%; big community scale has significant inhibition on growth of crayfish, thus, there should be barriers when cultivating Procambarus clarkia juvenile.

Multi-objective modeling and optimization for scheduling of cracking furnace systems

Cracking furnace is the core device for ethylene production. In practice, multiple ethylene furnaces are usually run in parallel. The scheduling of the entire cracking furnace system has great significance when multiple feeds are simultaneously processed in multiple cracking furnaces with the changing of operating cost and yield of product. In this paper, given the requirements of both profit and energy saving in actual production process, a multi-objective optimization model contains two objectives, maximizing the average benefits and minimizing the average coking amount was proposed. The model can be abstracted as a multi-objective mixed integer non- linear programming problem. Considering the mixed integer decision variables of this multi-objective problem, an improved hybrid encoding non-dominated sorting genetic algorithm with mixed discrete variables （MDNSGA-II） is used to solve the Pareto optimal front of this model, the algorithm adopted crossover and muta- tion strategy with multi-operators, which overcomes the deficiency that normal genetic algorithm cannot handle the optimization problem with mixed variables. Finally, using an ethylene plant with multiple cracking furnaces as an example to illustrate the effectiveness of the scheduling results by comparing the optimization results of multi-objective and single objective model.

Fermented mixed feed alters growth performance,carcass traits,meat quality and muscle fatty acid and amino acid profiles in finishing pigs

This study was conducted to investigate the effects of fermented mixed feed(FMF)on growth performance,carcass traits,meat quality,muscle amino acid and fatty acid composition and mRNA expression levels of genes related to lipid metabolism in finishing pigs.In the present study,144 finishing pigs(Duroc×Berkshire×Jiaxing Black)were randomly allocated to 3 dietary treatments with 4 replicate pens per group and 12 pigs per pen.The dietary treatments included a basal diet(CON),a basal diet+5%FMF and a basal diet+10%FMF.The experiment lasted 38 d after 4 d of acclimation.The results showed that 5%and 10%FMF significantly increased the average daily gain(ADG)of the females but not the males(P<0.05),but FMF supplementation showed no impact on carcass traits.Moreover,10%FMF supplementation increased the meat color45 min and meat color24 h values,while it decreased the shear force relative to CON(P<0.05).In addition,10%FMF significantly increased the contents of flavor amino acids(FAA),total essential AA(EAA),total non-EAA(NEAA)and total AA relative to CON(P<0.05).Furthermore,the diet supplemented with 10%FMF significantly increased the concentration of n-3 polyunsaturated fatty acids(PUFA),n-6 PUFA and total PUFA,and the PUFA to saturated fatty acids ratio(P<0.05),suggesting that FMF supplementation increased meat quality.Moreover,compared with the CON,10%FMF supplementation increased the mRNA expression of lipogenic genes,including CEBPα,PPARγ,SREBP1 and FABP4,and upregulated the expression of unsaturated fatty acid synthesis(ACAA1 and FADS2).Together,our results suggest that 10%FMF dietary supplementation improved the female pigs’growth performance,improved the meat quality and altered the profiles of muscle fatty acids and amino acids in finishing pigs.This study provides a reference for the production of high-quality pork.