Protein Disulfide Isomerase and Its Potential Function on Endoplasmic Reticulum Quality Control in Diatom Phaeodactylum tricornutum

PDI is a molecular chaperone and plays an important role in Endoplasmic Reticulum quality control (ERQC).PDI participates in the refolding of the misfolded/unfolded proteins to maintain cellular homeostasis under differentstresses. However, bioinformatic characteristics and potential functions of PDIs in diatom Phaeodactylumtricornutum (Pt) are still unknown so far. Hence, the genome-wide characteristics of PtPDI proteins in P. tricornutumwere first studied via bioinformatic and transcriptomic methods. 42 PtPDI genes were identified from thegenome of P. tricornutum. The motif, protein structure, classification, number of introns, phylogenetic relationship,and the expression level of 42 PtPDI genes under the tunicamycin stress were analyzed. A pair of tandemduplicated genes (PtPDI15 and PtPDI18) was observed in P. tricornutum. The 42 PtPDIs with different genecharacteristics were divided into three independent clades, indicating different evolutional relationships and functionsof these PtPDIs. The 14 up-regulated PtPDI genes under the tunicamycin treatment might have a positiveeffect on the ER quality control of the unfolded/misfolded proteins, while the 7 down-regulated PtPDIs mightnegatively affect the ERQC. The characteristics of all 42 PtPDIs and their proposed working model here providea comprehensive understanding of the PtPDIs gene family. The differential expression of 21 PtPDIs will be usefulfor further functional study in the ERQC.

Analysis of quality-related proteins in golden pompano(Trachinotus ovatus)fillets with modified atmosphere packaging under superchilling storage

Here,we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage.Tandem mass tags(TMT)-labeled quantitative proteomic strategy was applied to investigate the relationships between protein changes and quality characteristics of modified atmosphere packaging(MAP)fillets during superchilling(-3°C)storage.Scanning electron microscopy was used to show that the muscle histology microstructure of fillets was damaged to varying degrees,and low-field nuclear magnetic resonance was used to find that the immobilized water and free water in the muscle of fillets changed significantly.Total sulfhydryl content,TCA-soluble peptides and Ca2+-ATPase activity also showed that the fillet protein had a deterioration by oxidation and denaturation.The Fresh(FS),MAP,and air packaging(AP)groups were set.Total of 150 proteins were identified as differential abundant proteins(DAPs)in MAP/FS,while 209 DAPs were in AP/FS group.The KEGG pathway analysis indicated that most DAPs were involved in binding proteins and protein turnover.Correlation analysis found that 52 DAPs were correlated with quality traits.Among them,8 highly correlated DAPs are expected to be used as potential quality markers for protein oxidation and water-holding capacity.These results provide a further understanding of the muscle deterioration mechanism of packaging golden pompano fillets during superchilling.

Revealing the process of storage protein rebalancing in high quality protein maize by proteomic and transcriptomic

Quality protein maize(QPM)(Zea mays L.) varieties contain enhanced levels of tryptophan and lysine, exhibiting improved nutritive value for humans and livestock. However, breeding QPM varieties remains challenging due to the complex process of rebalancing storage protein. This study conducted transcriptome and proteome analyses to investigate the process of storage proteins rebalancing in opaque2(o2) and QPM. We found a weak correlation between the transcriptome and proteome, suggesting a significant modulating effect of post-transcriptional events on non-zein protein abundances in Mo17o2 and QPM. These results highlight the advantages of proteomics. Compared with Mo17, 672 differentially expressed proteins(DEPs) were identified both in Mo17o2 and QPM, and several of them were associated with storage protein, starch, and amino acid synthesis. We identified 178 non-zeins as DEPs in Mo17o2 and QPM kernels. The up-regulated non-zein DEPs were enriched in lysine, tryptophan, and methionine, which affected the protein quality. Co-expression network analysis identified regulators of storage protein synthesis in QPM, including O2,PBF1, and several transcription factors. Our results revealed how storage protein rebalancing occurs and identified nonzein DEPs that may facilitate superior-quality QPM breeding.

Rice Storage Proteins:Focus on Composition,Distribution,Genetic Improvement and Effects on Rice Quality

Rice storage proteins(RSPs)are plant proteins with high nutritional quality.As the second largest type of storage substance in rice,it is the main source of protein intake for people who consume rice as a staple food.The content and type of RSPs affect the appearance,processing quality and eating quality of rice.These effects involve the distribution of RSPs in rice grains as well as the interactions of RSPs with other components such as starch in rice grains.In the past two decades,some progress has been made in the genetic improvement of RSPs.However,the determination mechanism of protein content and composition in rice is still unclear,and the mechanism of the effect of RSPs on rice quality has not been elucidated.In this review,the composition,biosynthesis and distribution of RSPs,and quantitative trait loci mapping and cloning of RSP genes are summarized,the research progress of the influence of RSPs and their components on rice quality are reviewed,and the research directions in the future are proposed.

Effects of Different Protein Energy Ratios on Fattening Performance,Slaughter Performance and Meat Quality of Pigs

[Objectives]Protein energy ratio refers to the proportional relationship between protein and energy levels in animal diets,i.e.,the grams of crude protein corresponding to every megacalorie of energy,which is generally expressed as CP:ME or CP:DE.This study was conducted to investigate the effects of different diets on fattening and slaughter performance and meat quality traits for"L(Large Yorkshire)×L(Landrace)"crossbred pigs.[Methods]Eighteen piglets of L×L crossbred with similar body weights about 51 kg were selected.The piglets were divided into 3 groups randomly and each group was assigned to 3 replicates with 2 piglets in a replicate.Group A was fed diet Ⅰ (control diet),group B was fed the same diet of group A in the first month of the trial but fed diet Ⅱ in second month,and group C consumed diet Ⅲ.All the pigs were fed in the same feeding condition for two months except the different diets during the trial.One pig in similar body weight from each replicate was slaughtered for the determination of slaughter performance and meat quality traits in the end of the trial.[Results]The average daily feed intake(ADFI)of pigs from group B was only(2.32±0.52)kg and significantly lower than those from group A and group C(P<0.05),but no difference was found in average daily gain(ADG) and feed/gain(P>0.05).Also,no differences occurred in the carcass length,back fat thickness,longissimus muscle (LM) area and dressing percentage(P>0.05).In addition,no differences were found in the meat quality traits of shear force,meat color,pH_(45 min),pH_(24 h) and cooking loss(P>0.05).However,the water-holding capacity of meat from group C was(2.58±0.02)ms and significantly lower than that of(2.80±0.20)ms from group A(P<0.05).Although the contents of glutamic acid and cystine in LM from group B was significantly lower than those from group A and group C(P<0.05),no differences occurred in the contents of other amino acids,the total amino acid and total flavor amino acid among the three groups(P>0.05).However,the inosine monophosphate content of LM from group C was only(331.80±11.53)mg/100 g and significantly lower than those of(361.00±6.36)and(366.37±4.80)mg/100 g from group A and B(P<0.05).Even though no differences were found in the contents of DM and CP in LM among the three groups of pigs,the content of intramuscular fat(IMF)in LM from group B and group C was increased by 45.6%and 46.58%respectively from that of group A(P<0.05),but no difference occurred between group B and C(P>0.05).[Conclusions]DietsⅡ and Ⅲ in this study caused no differences in fattening and slaughter performance of L×L crossbred pigs,but the effects on some meat traits were still significant,especially on the improvement of intramuscular fat in experimental pigs.Therefore,they could improve the meat quality of crossbred pigs to a certain extent.

Influence of protein characteristics and the proportion of gluten on end-use quality in Korean wheat cultivars

The effects of protein characteristics and the proportion of gluten on end-use quality in 13 Korean wheat cultivars for three years were verified in this study. Year, cultivar, and the interaction between the year and the cultivar influenced protein characteristics, the proportion of gluten except for γ-and ω-gliadin using RP-HPLC(reversed-phase high-performance liquid chromatography), and end-use quality. Protein characteristics and the proportion of gluten in Korean wheat cultivars were between those of Australian standard white(ASW) and hard wheat(AH). Korean wheat cultivars exhibited a higher average α+β gliadin proportion than imported wheat, a γ-gliadin proportion similar to that of dark northern spring wheat, and the same ω-gliadin proportion as AH. They showed a bread-loaf volume intermediate between those of ASW and AH and a texture of cooked noodles similar to that of soft white wheat, but less springiness than imported wheat. The cookie diameter of Korean wheat cultivars was similar to that of hard red winter wheat. There was a correlation between bread-loaf volume and protein characteristics, except for the protein content in Korean wheat cultivars. Springiness and cohesiveness of cooked noodles were not correlated with protein characteristics, while hardness was correlated with the protein content and water absorption of a mixograph. Cookie diameter was negatively correlated with the sodium dodecyl sulfate(SDS) sedimentation volume and water absorption of a mixograph. The end-use quality was not correlated with any proportion of gluten composition. Principal component analysis(PCA) showed that the proportion of gluten was not related to the quality of the bread(both PCs, 81.3%), noodle(77.7%), and cookie(82.4%). PCA explained that Keumkang is suitable for superior bread, while Uri is good for cooked noodles and cookies.

Swelling Index of Glutenin (SIG) Related to Protein Quality, DoughCharacters and Noodle Quality

The swelling index of glutenin (SIG) and the protein fraction of 25 Chinese wheat varieties were studied with new protein fractions extracting method. The protein fractions compose of monomeric protein, soluble glutenin and insoluble glutenin. The relations between other protein index, dough character, and fresh noodle quality were also discussed. The SIG results at different time is positively and highly significantly related to the insoluble glutenin content (r= 0.808 -0.867, P< 0.01). The SIG result can reflect the insoluble glutenin content. The protein content, gluten index, farinograph stability time, extensibility length and extensigram energy were positively and significantly correlated with SIG5 and SIG20 (r= 0.516 - 0.734, P<0.05, 0.01).SIG proved to be applicable in Chinese wheat dough evaluation. Fresh noodle making quality parameters were evaluated by fresh noodle length, thickness, maximum resistance to extension, extension area and extension distance, while cooked noodle texture was determined by cutting firmness, compression recovery, surface firmness and TPA by using a texture analyzer of TA.XT2i. The noodle cooking quality was significantly correlated with SIG value. The surface firmness and cutting firmness were more desirable for predicating the quality difference than TPA test and compression. Cooking loss and water absorption were negatively related to SIG value and insoluble content (r = -0.556 - - 0.787, P < 0.05, 0.01). The results showed that SIG test was also suitable in evaluating noodle making and cooking quality in very small sample size, which was very important in wheat breeding programs. Therefore, SIG test, as a small scale test, is suitable to evaluate dough rheological properties for Chinese wheat varieties, and will be helpful in cereal research and wheat breeding program, especially, in early generations.

Protein Quality Evaluation of Animal Food Proteins by <i>In-Vitro</i>Methodologies

Animal protein foods are undoubtedly among the most concentrated source of essential amino acids (AA) for the human diet. However, their high prices and diseases associated to their excessive consumption have fomented the consumption of other alternative sources of animal proteins such as those from marine or aquatic species. Sonora is a well recognized producer of animal foods in Mexico, both terrestrial and aquatic. In this study, the protein quality evaluation of these animal food sources, highly produced and consumed in Sonora, is proposed, using in-vitro methodologies. Four different species, from each aquatic and terrestrial origin, were selected. Samples of lean muscle were used in all cases. Various in-vitro methodologies for protein quality evaluation were selected, alternatives to the animal bioassays: % digestibility, Total amino acid analyses (HPLC), PDCAAS, computerized PER calculations (C-PER and DC-PER) and total collagen contents. % in-vitro digestibility presented significant differences among samples from terrestrial species, but muscle from aquatic species did not showed significant differences. All sources of proteins, both aquatic and terrestrial proved to be rich sources of essential amino acids. PDCAAS was unable to establish significant differences in protein quality among sources of protein from different origin. Both methods C-PER and DC-PER were more exact in their results and were able to detect significant differences among samples of different origin. An important finding was the great difference in the total collagen content between aquatic and terrestrial sources of proteins, where terrestrial muscle proteins had almost 10-time more collagen than aquatic protein sources. However, these collagen contents did not seem to have a significant influence in the protein quality of these animal proteins. These muscle proteins, from both aquatic and terrestrial species, confirmed to have a high protein quality and some of the in-vitro methodologies used in this study represent a valuable alternative to the animal bioassays.

Effects of dietary protein/energy ratio on growth performance,carcass trait,meat quality,and plasma metabolites in pigs of different genotypes

Background： The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes. Methods： Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups （Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment） in a 2 x 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases. Results： We observed significant interactions （P 〈 0.05） between breed and diet for total fat percentage, intramuscular fat （IMF） content, protein content in biceps femoris （BF） muscle, and plasma urea nitrogen （UN） concentration in the nursery phase; for average daily gain （ADG）, average daily feed intake （ADFI）, dry matter, IMF content in psoas major （PM） muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced （P 〈 0.05） growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher （P 〈 0.0_5） ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower （P 〈 0.0.5） feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN. Conclusions： Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.

Studies on Reducing Nitrogen Excretion: Ⅰ. Net Energy Requirement of Finishing Pigs Maximizing Performance and Carcass Quality Fed Low Crude Protein Diets Supplemented with Crystalline Amino Acids

Two experiments were conducted to in- vestigate the effects of net energy （NE） level on the performance and carcass traits of finishing pigs fed low crude protein （CP） diets supplemented with crystalline amino acids （CAA）. A total of 216 （Exp. 1） and 360 （Exp. 2 ） barrows （ Yorkshire × Landrace× Duroc ） were allotted to one of six treatments （n =6）. The experimental diets were based on corn and soybean meal, and consisted of a high-CP diet that contained approximately 16% CP and 2.50 Mcal/kg of NE as well as five low-CP diets in which the CP level of the diet was reduced by approximately four percentage units but was supplemented with crystalline lysine, methionine, threonine, and tryptophan. The low CP diets provided 2.64, 2.58, 2.50, 2.42, or 2.36 Mcal/kg in Exp. 1 as well as 2.45, 2.40, 2.35, 2.30, or 2.25 Mcai/kg in Exp.2. In Exp. 1, a linear （P=0.03） increase in weight gain was observed with decreasing NE level while the ratio of gain to feed was unaffect- ed （P 〉 0.05） by NE level. There was a linear in-crease （P = 0.01 ） in the percentage of fat-free lean and a linear decrease （ P = 0.03 ） in the percentage of total fat with decreasing NE levels. In Exp. 2, a sig- nificant quadratic （ P = 0.03 ） effect of NE level was observed for weight gain. The ratio of gain to feed demonstrated a significant （P 〈0.01 ） quadratic effect with pigs fed 2.35 and 2.40 Mcal/kg of NE, Pigs fed the diet containing 2.40 Mcal/kg of NE had the lowest percentage of total fat （36. 95% ） and the highest percentage of fat-free lean （49.36%）. The overall results of these experiments indicate that feed- ing either a surplus or a deficiency of NE is detrimen- tal to both pig performance and carcass composition when low CP diets supplemented with CAA are fed. Our results indicate that when the CP content of the diet is reduced by four percentage units and the diet is properly supplemented with CAA, maximum per- formance and carcass quality will be obtained if the diet provides approximately 2.42 Mcal/kg of NE.

Effects of lairage after transport on post mortem muscle glycolysis, protein phosphorylation and lamb meat quality

The objective of this study was to investigate the effect of lairage after transport on post mortem muscle glycolysis,protein phosphorylation and lamb meat quality.Two preslaughter animal treatments,transport for 3 h and lairage for 0 h（T3L0）and transport for 3 h and then lairage for 12 h（T3L12）,were compared with a control treatment of 0 h transport and 0 h lairage.Data obtained showed that preslaughter transport had a significant effect on lamb meat quality.Loins from lambs of the T3L0 treatment showed higher（P=0.026）pH24 h and higher（P=0.021）pH48 h values,but lower（P〈0.001）drip loss and lower（P〈0.05）glycolytic potential at 0 h post mortem than those of the T3L12 and control groups.Muscle samples of the T3L0 group showed higher（P=0.046）shear force and lower（P=0.005）b＊ value than those of the T3L12 group.Muscle glycogen concentration at 0,2,4 h post mortem were lower（P〈0.05）in the T3L0 group than in control.No significant difference（P〉0.05）in most meat quality parameters was determined between the T3L12 group and control,showing lairage for 12 h allowed lambs to recover from the effects of transport for 3 h and resulted in similar meat quality characteristics compared to no transport.Lairage after transport did not affect most meat quality indices in comparison with control,but increased the meat drip loss and b＊value of lambs possibly through decreasing glycogen concentration and glycolytic potential.

The Effect of Varied Dietary Crude Protein Levels with Balanced Amino Acids on Performance and Egg Quality Characteristics of Layers at First Laying Phase

Four diets were formulated to study the influence of varying crude protein levels on the performance, egg quality, serum and haematological characteristics at the first phase of laying cycle of sixty Bovan Nera laying birds that were randomly allotted to dietary treatments. The four experimental diets had five replicates each and three birds per repli-cate. Diet 1 contained 14% crude protein (CP), while diet 2 contained 15% CP, diets 3 and 4 contained 16% and 17% CP respectively. The experimental birds were fed for 10 weeks and the data collected were statistically analysed. Apparent variations recorded for all the performance characteristics such as Egg number, Hen-day production, Feed Conversion Ratio (FCR) and weight gain were significantly different (p < 0.05). The best FCR value were recorded by birds fed 17% CP (3.45), while the highest weight gain mean value were also recorded by birds fed 17% CP value. Findings indicated a direct relationship between dietary crude protein values and performance.

Effects of different dietary energy and protein levels and sex on growth performance,carcass characteristics and meat quality of F1 Angus x Chinese Xiangxi yellow cattle

Background：The experiment evaluated the effect of nutrition levels and sex on the growth performance,carcass characteristics and meat quality of F1 Angus × Chinese Xiangxi yellow cattle.Methods：During the background period of 184 d,23 steers and 24 heifers were fed the same ration,then put into a2×2×2 factorial arrangement under two levels of- dietary energy（TON：70/80%DM）,protein（CP：11.9/14.3%DM）and sex（S：male/female） during the finishing phase of 146 d.The treatments were-（1） high energy/low protein（HELP）,（2） high energy/high protein（HEHP）,（3） low energy/low protein（LELP） and（4） low energy/high protein（LEHP）.Each treatment used 6 steers and 6 heifers,except for HELP- 5 steers and 6 heifers.Results：Growth rate and final carcass weight were unaffected by dietary energy and protein levels or by sex.Compared with the LE diet group,the HE group had significantly lower dry matter intake（DMI,6.76 vs.7.48 kg DM/d）,greater chest girth increments（46.1 vs.36.8 cm）,higher carcass fat（19.9 vs.16.3%） and intramuscular fat content（29.9 vs.22.8%DM）.The HE group also had improved yields of top and medium top grade commercial meat cuts（39.9 vs.36.5%）.The dressing percentage was higher for the HP group than the LP group（53.4 vs.54.9%）.Steers had a greater length increment（9.0 vs.8.3 cm）,but lower carcass fat content（16.8 vs.19.4%） than heifers.The meat quality traits（shear force value,drip loss,cooking loss and water holding capacity） were not affected by treatments or sex,averaging 3.14 kg,2.5,31.5 and 52.9%,respectively.The nutritive profiles（both fatty and amino acid composition） were not influenced by the energy or protein levels or by sex.Conclusions：The dietary energy and protein levels and sex significantly influenced the carcass characteristics and chemical composition of meat but not thegrowth performance,meat quality traits and nutritive profiles.

Effects of water deficit and high N fertilization on wheat storage protein synthesis,gluten secondary structure,and breadmaking quality

The content and composition of wheat storage proteins are the major determinants of dough rheological properties and breadmaking quality and are influenced by cultivation conditions.This study aimed to investigate the effects of water deficit and high N-fertilizer application on wheat storage protein synthesis,gluten secondary structure,and breadmaking quality.Reverse-phase ultrahigh-performance liquid chromatography analysis showed that storage protein and gluten macropolymer accumulation was promoted under both independent applications and a combination of water-deficit and high N-fertilizer treatments.Fourier-transform infrared spectroscopy showed that water deficit and high N-fertilizer treatments generally improved protein secondary structure formation and lipid accumulation,and reduced flour moisture.In particular,high N-fertilizer application increasedβ-sheet content by 10.4%and the combination of water-deficit and high N-fertilizer treatments increased random coil content by 7.6%.These changes in gluten content and secondary structure led to improved dough rheological properties and breadmaking quality,including superior loaf internal structure,volume,and score.Our results demonstrate that moderately high N-fertilizer application under drought conditions can improve gluten accumulation,gluten secondary structure formation,and baking quality.

Quality deterioration and improvement of wheat gluten protein in frozen dough

Frozen dough technology can effectively recover sensory quality of frozen flour products.This technique has gradually drawn the research interest in the industrialization of staple food.However,the quality of the final frozen products remains inferior to that of fresh products.This study reviewed the deterioration of gluten network in dough caused by ice recrystallization and various additives.This study also investigated the optimization of the freezing process and other empirical improvement techniques.Suggestions for future research were also provided.

Effects of Different Dietary Energy and Protein Levels on Meat Performance and Meat Quality of Jinghai Yellow Chickens

To investigate the effect of different dietary energy and protein levels on meat performance and meat quality of Jinghai yellow chickens, 480 43-day old Jinghai yellow chickens with similar weight were randomly divided into four experimental groups： experimental group 1 （protein 15%, metabolic energy 9.95 MJ/kg）, experimental group 2 （protein 16%, metabolic energy 10.95 MJ/kg）, experimental group 3 （protein 17%, metabolic energy 12.65 MJ/kg） and experimental group 4 （ protein 18%, metabolic energy 13.95 MJ/kg）, respectively. All chickens were slaughtered at 112-day old. The breast and leg muscles of Jinghai yellow chickens were collected, to determine the slaughter performance, conventional meat quality and muscle chemical indicators. The results indicated that dressing-out percentage and eviscerated yield percentage in four experimental groups were above 87.27% and 67.00%, respectively; other slaughter performance indicators exhibited no significant differences among various groups （P 〉 0.05 ） ; breast muscle color of hens in experimental group 4 varied significantly from that in other three groups （ P 〈 0.05 ） ; leg muscle color of hens in experimental group 2 varied extremely significantly from that in other three groups （ P 〈 0.01 ） ; water-holding capacity of breast muscles of hens in experimental group 3 was significantly higher than that in experimental group 4 （P 〈 0.05 ） ; thiamine content of breast muscles of cocks in experimental group 3 was significandy higher than that in experimental group 2 （ P 〈 0.05 ） ; however, other properties exhibited no significant differenees among various groups （P 〉 0.05 ）.

Effects of Dietary Protein and Temperature on Growth and Flesh Quality of Songpu Mirror Carp

The study was conducted to demonstrate the effects of dietary protein and water temperature on growth and flesh quality of Songpu mirror carp （Cyprinus carpio） at an initial weight （165.24±5.08） g. Practical diets were formulated to contain five protein levels （29.12%, 31.46%, 34.49%, 38.17%, and 40.13%）, and each diet was randomly assigned triplicate groups of 15 fishes at three temperatures （18℃, 22℃, and 26℃） in the recirculation system. Fishes were fed twice daily to apparent satiation for 56 days. Results indicated that fishes had higher weight gain rate at 22℃ and 26℃ than that at 18℃ （P〈0.05）, but there were no significant differences between 22℃ and 26℃ （P〉0.05）. Based on the weight gain rate, dietary protein level 29.12% could meet the requirement of the body at 18℃, 22℃, or 26℃. Crude protein, crude lipid, moisture and ash of muscle had no significant differences among those treatments （P〉0.05）. pH （after 24 h） of muscle was the highest at 18℃ and the lowest at 22℃ （P〈0.05）, but no differences were observed among different protein level groups at each temperature （P〉0.05）. No significant differences on shear force, water holding capacity, collagen, glycogen and lactate among all the treatments were found （P〉0.05）. It was concluded that when C. carpio fed to apparent satiation, the growth mainly depended upon temperature. Dietary protein could not significantly affect flesh quality, but temperature significantly affected pH of muscles. A dietary protein level 29.12% could meet the requirement of the body at 18℃, 22℃, or 26℃.

Foliar applications of various nitrogen(N)forms to winter wheat affect grain protein accumulation and quality via N metabolism and remobilization

Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various N forms(NO_(3)^(-),urea,NH_(4)^(+))at anthesis was performed to measure their effects on wheat grain protein accumulation,quality formation,and the underlying mechanisms.Foliar application of three N forms showed varying effects in improving grain gluten proteins and quality traits.Under NH_(4)^(+) application,there was more post-anthesis N uptake for grain filling,with relatively strong increase in enzyme activities and gene expression associated with N metabolism in flag leaves at 8–20 days after anthesis(DAA),whereas its promotion of grain N metabolism became weaker after 20 DAA than those under NO_(3)^(-) and urea treatments.More N was remobilized from source organs to grain under treatment with foliar NO_(3)^(-) and urea.Genes controlling the synthesis of gluten protein and disulfide bonds were upregulated by NO_(3)^(-) and urea at 20–28 DAA,contributing to increased grain protein content and quality.Overall,foliar applications of NO_(3)^(-) and urea were more effective than those of NH_(4)^(+) in increasing grain N filling.These findings show that manipulating the source–sink relationship by reinforcing grain N metabolism and N remobilization is critical for optimizing grain protein accumulation and quality formation.

Protein quality of four indigenous edible insect species in Nigeria

Food security is a serious concern particularly for developing countries.To overcome hunger and malnutrition there is a need for increased research towards finding alternative and cheaper sources of nutrients.Insects have been reported to be rich in protein and could be alternative sources of protein.This work was therefore designed to determine the protein quality of moth caterpillar,termite,cricket and grasshopper and the effects of diets supplemented with these insects on some biochemical and haematological indices of rats.The amino acid compositions of the insects were determined using standard analytical methods.Five iso-nitrogenous and isocaloric diets were formulated on a 10%protein basis with the insects and casein.A Nitrogen free diet was also formulated as control.Thirty six(36)young weanling albino rats(21–28 days old)were divided into 6 groups and fed with the diets ad libitum for 28 days.Their weekly weight gain and daily feed intake were recorded,urine and faeces were collected for nitrogen determination using Kjedahl method and the data obtained used to calculate the various protein quality indices.After the feeding trial periods,the rats were sacrificed,blood samples collected and organs excised for various analyses.Cricket was found to have the highest amino acid score(0.91),protein efficiency ratio(1.78),net protein ratio(3.04)biological value(93.02%)and protein digestibility corrected for amino acid score(0.73)as compared to other insect proteins analysed.The organ body weight ratios of the liver,spleen,lung and heart of rats placed on the insect supplemented diets were not significantly different(p>0.05)from those fed with casein and basal diets.Serum total protein concentrations in rats fed with cricket diet were not significantly different(p>0.05)from those fed casein diet while serum LDL cholesterol concentration was lowest in rats fed cricket diet.The finding in this work that the selected insects are nutritious and safe for consumption may alleviate the fear of entomophagy thereby reducing the overdependence on conventional animal proteins.

Accumulation of Protein Fractions during Grain Filling of Wheat Genotypes Differing in Protein Content and Baking Quality

The accumulation of protein fractions was analyzed on developing and mature wheat grains of three cultivars differing in protein content and baking quality. There was a slight difference in the accumulation of cytoplasmic proteins in the cultivars used. The high yield but low protein cultivar showed a consistent decline of protein content during grain filling but the high - protein cultivars increased their psotein contant after 25 days post-anthcsis. The accumulation of storage proteins was different from that of cytoplasmic protein, and there were also cultivar variations. However, all cultivars reached their, maximum-synthesizing capacity for storage proteins at maturity. The relationship between the protein fractions or their ratio and baking quality was also discussed.