Dynamic changes of rumen microbiota and serum metabolome revealed increases in meat quality and growth performances of sheep fed bio‑fermented rice straw

Background Providing high-quality roughage is crucial for improvement of ruminant production because it is an essential component of their feed.Our previous study showed that feeding bio-fermented rice straw(BF)improved the feed intake and weight gain of sheep.However,it remains unclear why feeding BF to sheep increased their feed intake and weight gain.Therefore,the purposes of this research were to investigate how the rumen micro-biota and serum metabolome are dynamically changing after feeding BF,as well as how their changes influence the feed intake,digestibility,nutrient transport,meat quality and growth performances of sheep.Twelve growing Hu sheep were allocated into 3 groups:alfalfa hay fed group(AH:positive control),rice straw fed group(RS:negative control)and BF fed group(BF:treatment).Samples of rumen content,blood,rumen epithelium,muscle,feed offered and refusals were collected for the subsequent analysis.Results Feeding BF changed the microbial community and rumen fermentation,particularly increasing(P<0.05)relative abundance of Prevotella and propionate production,and decreasing(P<0.05)enteric methane yield.The histomorphology(height,width,area and thickness)of rumen papillae and gene expression for carbohydrate trans-port(MCT1),tight junction(claudin-1,claudin-4),and cell proliferation(CDK4,Cyclin A2,Cyclin E1)were improved(P<0.05)in sheep fed BF.Additionally,serum metabolome was also dynamically changed,which led to up-regulating(P<0.05)the primary bile acid biosynthesis and biosynthesis of unsaturated fatty acid in sheep fed BF.As a result,the higher(P<0.05)feed intake,digestibility,growth rate,feed efficiency,meat quality and mono-unsaturated fatty acid concentration in muscle,and the lower(P<0.05)feed cost per kg of live weight were achieved by feeding BF.Conclusions Feeding BF improved the growth performances and meat quality of sheep and reduced their feed cost.Therefore,bio-fermentation of rice straw could be an innovative way for improving ruminant production with mini-mizing production costs.

Effects of dietary Clostridium butyricum and rumen protected fat on meat quality,oxidative stability,and chemical composition of finishing goats

Background Clostridium butyricum(CB)is a probiotic that can regulate intestinal microbial composition and improve meat quality.Rumen protected fat(RPF)has been shown to increase the dietary energy density and provide essential fatty acids.However,it is still unknown whether dietary supplementation with CB and RPF exerts beneficial effects on growth performance and nutritional value of goat meat.This study aimed to investigate the effects of dietary CB and RPF supplementation on growth performance,meat quality,oxidative stability,and meat nutritional value of finishing goats.Thirty-two goats(initial body weight,20.5±0.82 kg)were used in a completely randomized block design with a 2 RPF supplementation(0 vs.30 g/d)×2 CB supplementation(0 vs.1.0 g/d)factorial treatment arrangement.The experiment included a 14-d adaptation and 70-d data and sample collection period.The goats were fed a diet consisted of 400 g/kg peanut seedling and 600 g/kg corn-based concentrate(dry matter basis).Result Interaction between CB and RPF was rarely observed on the variables measured,except that shear force was reduced(P<0.05)by adding CB or RPF alone or their combination;the increased intramuscular fat(IMF)content with adding RPF was more pronounced(P<0.05)with CB than without CB addition.The pH24h(P=0.009),a*values(P=0.007),total antioxidant capacity(P=0.050),glutathione peroxidase activities(P=0.006),concentrations of 18:3(P<0.001),20:5(P=0.003)and total polyunsaturated fatty acids(P=0.048)were increased,whereas the L*values(P<0.001),shear force(P=0.050)and malondialdehyde content(P=0.044)were decreased by adding CB.Furthermore,CB supplementation increased essential amino acid(P=0.027),flavor amino acid(P=0.010)and total amino acid contents(P=0.024)as well as upregulated the expression of lipoprotein lipase(P=0.034)and peroxisome proliferator-activated receptorγ(PPARγ)(P=0.012),and downregulated the expression of stearoyl-CoA desaturase(SCD)(P=0.034).The RPF supplementation increased dry matter intake(P=0.005),averaged daily gain(trend,P=0.058),hot carcass weight(P=0.046),backfat thickness(P=0.006),concentrations of 16:0(P<0.001)and c9-18:1(P=0.002),and decreased the shear force(P<0.001),isoleucine(P=0.049)and lysine content(P=0.003)of meat.In addition,the expressions of acetyl-CoA carboxylase(P=0.003),fatty acid synthase(P=0.038),SCD(P<0.001)and PPARγ(P=0.022)were upregulated due to RPF supplementation,resulting in higher(P<0.001)content of IMF.Conclusions CB and RPF could be fed to goats for improving the growth performance,carcass traits and meat quality,and promote fat deposition by upregulating the expression of lipogenic genes of Longissimus thoracis muscle.

Effects of Fermented Puffed Feather Meal on Growth Performance,Serum Biochemical Indices,Meat Quality,and Intestinal Microbiota in Broilers

This study aimed to investigate the effects of fermented puffed feather meal(FPFM)on growth performance,serum biochemical indices,meat quality,and intestinal microbiota in Arbor Acres(AA)broilers.A single-factor design was adopted,and four treatments were administered with five replicates to 240 one-day-old AA broilers.The control group(group A)received a basal diet,while the experimental groups received a basal diet plus 33%(group B),67%(group C)and 100%(group D)FPFM,respectively.Compared with group A,(1)the average daily gain(ADG)in group C decreased(P<0.05),and the feed conversion ratio(FCR)in group D increased(P<0.05);(2)the level of serum urea nitrogen in treatment groups decreased(P<0.05),and the levels of triglyceride,high density lipoprotein,low density lipoprotein,cholesterol,and glucose contents in group D increased(P<0.05)at day 21;(3)the serum immunoglobulin M and immunoglobulin G in group B and the immunoglobulin A in group C increased(P<0.05)at day 21,and the serum immunoglobulin M and immunoglobulin G in group D decreased(P<0.05)at day 42;(4)the share force of breast muscle and thigh muscle in group D increased(P<0.05);(5)the villus height to crypt depth ratio in the jejunum of group B increased(P<0.05)at day 21,and the villus height in group C and D increased(P<0.05)at day 42;(6)the proteobacteria counts in the cecum digesta in treatment groups decreased(P<0.05)at day 21.The basal diet supplemented with 33%FPFM promoted protein metabolism,enhanced immunity and improved meat quality,promoted the digestion and absorption of nutrients,increased intestinal microbial diversity,and improved the content of beneficial bacteria without affecting the growth performance,it was possible to be used as a good substitute for fish meal.

Improving the accuracy of genomic prediction for meat quality traits using whole genome sequence data in pigs

Background Pork quality can directly affect customer purchase tendency and meat quality traits have become valu-able in modern pork production.However,genetic improvement has been slow due to high phenotyping costs.In this study,whole genome sequence(WGS)data was used to evaluate the prediction accuracy of genomic best linear unbiased prediction(GBLUP)for meat quality in large-scale crossbred commercial pigs.Results We produced WGS data(18,695,907 SNPs and 2,106,902 INDELs exceed quality control)from 1,469 sequenced Duroc×(Landrace×Yorkshire)pigs and developed a reference panel for meat quality including meat color score,marbling score,L*(lightness),a*(redness),and b*(yellowness)of genomic prediction.The prediction accuracy was defined as the Pearson correlation coefficient between adjusted phenotypes and genomic estimated breeding values in the validation population.Using different marker density panels derived from WGS data,accuracy differed substantially among meat quality traits,varied from 0.08 to 0.47.Results showed that MultiBLUP outperform GBLUP and yielded accuracy increases ranging from 17.39%to 75%.We optimized the marker density and found medium-and high-density marker panels are beneficial for the estimation of heritability for meat quality.Moreover,we conducted genotype imputation from 50K chip to WGS level in the same population and found average concord-ance rate to exceed 95%and r^(2)=0.81.Conclusions Overall,estimation of heritability for meat quality traits can benefit from the use of WGS data.This study showed the superiority of using WGS data to genetically improve pork quality in genomic prediction.

Transcriptome analysis reveals the mechanism of chronic heat stress on meat quality of broilers

Background:Chronic heat stress has a negative impact on poultry meat quality.Although this has been extensively investigated,previous studies have primarily focused on metabolic alterations and oxidative stress in the pectoralis major(PM)muscle under chronic heat stress,and not all of the underlying molecular mechanisms are completely understood.Methods:A total of 144 male Arbor Acres broilers(28 d old)were randomly allocated into 3 treatment groups:(1)the normal control(NC)group,with broilers raised at 22℃and fed a basal diet;(2)the heat stress(HS)group,with birds raised at 32℃and fed a basal diet;and(3)the pair-fed(PF)group,with birds raised at 22℃and fed the amount of feed equal to the feed consumed on the previous day by the HS group.The experiment lasted for 14 d.Results:Chronic heat stress decreased the average daily feed intake and average daily gain,increased feed:gain ratio(P<0.05);and increased drip loss,cooking loss,shear force,hardness,and decreased p H,redness(a*);and springiness of PM muscle(P<0.05).Furthermore,chronic heat stress decreased muscle fiber density,increased connective tissue,and led to intracellular vacuolation.The transcriptome analyses indicated that the effect of chronic heat stress on meat quality was not only related to metabolism and oxidative stress,but also to signal transduction,immune system,transport and catabolism,cell growth and death,and muscle structure.Conclusions:Chronic heat stress has a negative impact on the growth performance,meat quality,and the PM muscle structure of broilers.Transcriptome analysis revealed a comprehensive understanding of the mechanism of the chronic heat stress-induced deterioration of broiler meat quality at the transcriptional level.

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.

Effects of Addition of Amino Acids or Soybean Phospholipid in Diet on Slaughter Performance and Meat Quality of Pigs

[Objectives]The study aims to discuss the effects of addition of arginine and glutamic acid or soybean phospholipid,vitamin E and yeast selenium in diet on the slaughter performance and meat quality of long(white)×large(York)binary hybrid pigs.[Methods]27 long×large castrated hybrid boars with the body weight of(54.4±0.15)kg were randomly divided into 3 groups,with 3 replicates per group and 3 pigs per replicate.Group A was the control group,in which the pigs were fed basal diet;in group B,0.8%arginine and 0.60%glutamate were added to the basal diet;in group C,75 g of soybean phospholipid,20 g of vitamin E and 8 g of yeast selenium were added to every 100 kg of the basal diet.The trial period was 60 d.After the experiment was ended,one test pig with similar body weight was selected from each replicate for slaughter and meat determination.[Results]The average weight gain and eye muscle area of the pigs in group B were significantly higher than those in group C(P<0.05),and also showed an increasing trend compared with group A,but there was no statistically significant difference(P>0.05);there was no significant difference between group B or C and group A in the average weight gain and eye muscle area(P>0.05).There was no significant difference in other slaughter performance between the three groups(P>0.05).Besides,there was also no significant difference in the content of various amino acids,total amino acids and total umami amino acids between the three groups(P>0.05).The inosine content in the longissimus dorsi muscle and muscle cooking loss of binary hybrid pigs in group C were significantly better than those in group B(P<0.05),and also had a tendency to be better than those in group A,but there was no significant difference(P>0.05);there was no significant difference between group B or C and group A in the inosine content and muscle cooking loss of the pigs(P>0.05).In addition,there was no significant difference in other meat traits and chemical composition of the longissimus dorsi muscle between group B or C and group A(P>0.05).[Conclusions]The addition of arginine and glutamic acid or soybean phospholipid,vitamin E and yeast selenium in diet had no significant effect on the growth rate,slaughter performance and meat traits of long×large binary hybrid pigs.

Effect of Chinese Herbal Feed Additive on Meat Quality of Rex Rabbit

[ Objective] The aim of this study was to provide a theoretical basis for population and application of Chinese herbal feed additive in the rex rabbit breeding. [ Methyl] 108 weaned -rex rabbits aged 40 days were divided into three groups with thirty -six each group. Group A were fed basal diet, while group B were fed basal diet supplemented with 0.3% Chinese herbal feed additive and group C were fed basal diet supplemented with 0.4% Chinese herbal feed additive. The meat quality indexes were measured when feeding to 150 age in days. [ Result] There was significant difference among pH value, water loss rate, storing loss rate and crude protein content in each group （P〈0.05）, but no significant difference was found in tenderness, cooking percentage, moisture content and crude fat content （ P 〉 0.05）. The total content of ami- no acids, essential amino acids and semi essential amino acids as well as main delicious amino acids was highest in group C accounting for 23.84%, 11.47% and 8.32% respectively, next came group B accounting for 20.94%, 10.64% and 6.81% respectively, and lowest in group C （ control group） accounting for 19.06%, 9.61% and 6.46% respectively. [ Conclusion] The Chinese herbal feed additive can improve meat quality of rex rabbit the best addition of 0.4%.

A Review on Tibetan Swine(a)——Carcass,Meat Quality,Basic Nutrition Component,Amino Acids,Fatty Acids,Inosine Monophosphate and Muscle Fiber

In this review, the carcass, meat quality, internal organs, basic nutrition component, amino acids （AAs）, fatty acids, inosine monophosphate （IMP） and mus- cle fiber of Tibetan swine were summarized for the first time. The formation mecha- nism of excellent features was analyzed from the aspects of physiological traits, ge- ographical environments and constraint reasons. Thereby, the outstanding features of Tibetan swine could be extended continuously, and the poor characteristics should be improved in the future.

Research on the Effect of Microbial Fermentation Feeds on Slaughter Performance and Meat Quality in Pig with Large-scale Feeding

In this paper, Duroc-lanndrae-Yorkshire crossbred piggy of born at 75 days of age, bouncing with health and similar body weight were randomly divided into experimental group （136 pigs） and control group （136 pigs）. Pigs in control group were fed with conventional diets, and 4% microbial fermentation feeds were added to the basal diet of experimental group to research on the effect of performance and meat quality of pig breeding. The results indicated that after feeding 106 d, compared to control group, the slaughter performance, meat quality and content of fatty acid and amino acid of experimental group were all better, its slaughter rate increased 1.53%, the carcass weight increased 2.75% and the backfat thickness decreased 0.02 cm. In addition, the pork meat in test group hadn＇t antibiotic and heavy metal residues, while it had higher color score, lower pH45min and pH24h value, better tenderness and rate of cooked meat and higher content of fatty acids, polyunsaturated fatty acids and amino acids. Microbial fermentation feed using in test group can significantly improved the flavor and aroma of pork, and eating this pork conducive more to human health. Thus, the application of microbial fermenta- tion feed can provide a more safe, healthy and nutritious flavor pork for human beings.

Analysis of Correlation between the Slaughter Performance and Meat Quality of Frizzle Chicken

[Objective]This study aimed to evaluate the meat quality of frizzle Chick-en, and to find out the correlation between the meat quality and slaughter perfor-mance. [Method] The slaughter performance such as live chicken weight, carcass weight, semi-eviscerated weight, eviscerated weight, chest muscle weight, leg mus-cle weight, abdominal fat weight and the meat quality indices like color, pH and shear force of 12-week-old frizzle chickens were measured to analyze the correla-tion between slaughter performance and meat quality. [Result] The carcass percent-age, semi-eviscerated percentage, eviscerated percentage, chest muscle percentage, leg muscle percentage, abdominal fat percentage, intramuscular fat width and subcu-taneous fat thickness of the male chickens were 89.76%, 81.54%, 67.53%, 7.82%, 11.29%, 2.42%, 0.69 cm and 0.48 cm, of female chickens were 89.78%, 80.87%, 62.94%, 6.19%, 9.92%, 3.91%, 0.78 cm and 0.61 cm. Some of these traits exhibit-ed significant difference between the male and female chickens （P〈0.05）. In male chickens, the chest muscle color, pH and shear force were 5.93, 6.15 and 3.72 kg, and the leg muscle color, pH and shear force were 6.18, 6.54 and 3.41 kg; in fe-male chickens, the chest muscle color, pH and shear force were 5.77, 6.05 and 3.41 kg, and the leg muscle color, pH and shear force were 6.03, 6.21 and 2.74 kg. The quality of chest and leg muscles of frizzle chickens significantly differed （P〈0.05）. Carcass weight had significant positive correlations with semi-eviscerated weight and meat color （P〈0.05）, and an extremely significant positive correlation with pH （P〈0.01）. Semi-eviscerated weight and pH value shared a significant posi-tive correlation （P〈0.05）. Eviscerated weight and leg muscle weight shared an ex-tremely significant negative correlation （P〈0.01）. Abdominal fat weight correlated sig-nificantly and negatively with shear force （P〈0.05）. Meat color and pH value had a significant positive correlation （P〈0.05）. [Conclusion] This study provides theoretical basis for the breeding of excellent chicken varieties producing high-quality meat.

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.

Different dietary starch sources alter the carcass traits, meat quality, and the profile of muscle amino acid and fatty acid in finishing pigs

Background: With increasing health awareness among consumers, the demand for healthier, tastier, higher quality and nutritional value pork is increasing. It has been shown that different dietary starch sources can alter the carcass traits and meat quality. However, research on the effects of different starch sources with clear different amylose/amylopectin ratio on the amino acid and fatty acid composition in Longissimus thoracis(L. thoracis) muscle of pigs is limited. This study aimed to investigate the effects of different dietary starch sources on carcass traits, meat quality, muscle amino acid and fatty acid composition, and the mRNA expression levels of genes involved in lipid metabolism and muscle fiber characteristics in finishing pigs. A total of 72 Duroc × Landrace × Large White barrows were randomly allocated to 3 different dietary treatment groups with 8 replicate pens/group and 3 pigs per pen.Tapioca starch(TS), corn starch(CS), and pea starch(PS), with amylose/amylopectin ratio of 0.11, 0.25, and 0.44,respectively, were used as their dietary starch sources for 40 days.Results: Results showed that the PS diet significantly increased(P < 0.05) the final body weight, average daily gain,loin-eye area, and fat-free lean index compared with the TS diet, but significantly decreased(P < 0.05) the feed to gain ratio and backfat thickness. Compared with the TS diet, PS diet also increased(P < 0.05) the pH45 min, marbling scores, the content of intramuscular fat and inosine monophosphate in the L. thoracis, and decreased(P < 0.05) the drip loss and shear force. In addition, compared with the TS diet, PS diet increased(P < 0.05) the proportions of flavor amino acids, DHA, EPA, and n-3 polyunsaturated fatty acid(PUFA) in the L. thoracis compared with TS diet,but decreased(P < 0.05) the ratio of n-6/n-3 PUFA. Furthermore, compared with the TS diet, PS diet also upregulated(P < 0.05) the lipogenic genes(FAS, LPL, SCD, ACCα) and myosin heavy-chain(MyHC)-IIa mRNA expression levels compared with the TS diet, but downregulated(P < 0.05) the CPT1 B and MyHC-IIb mRNA levels.Conclusions: In conclusion, these results provided compelling evidence that the different dietary starch source altered the carcass traits, meat flavor and quality in finishing pigs, and consumption of a diet with higher amylose/amylopectin ratio results in the production of a healthy, higher quality, and nutritional value pork.

Incorporation of meat quality and use of ultrasound technology for swine genetic improvement programs

Real-time ultrasound has been, and will continue to be, one of the most important tools in enhancing genetic improvement in the U.S. Recent advancements in the technology have allowed ultrasound to be used in evaluating intramuscular fat in live animals. Together with other genetic improvement tools, ultrasound technology will offer seedstock producers the opportunity to select for improved IMF in potential breeding stock replacements and hence speed genetic progress for the improvement of this trait. After three generations of selection for IMF using real-time ultrasound in an Iowa State University study, the average EBV for select line pigs is 0.83% greater than for control line pigs. Selection for IMF has, however, resulted in slightly more backfat and less loin muscle area, and a trend toward more days to 114 kg in the select line compared to the control line. Carcass evaluation of a sample of pigs from each litter indicated a similar increase in IMF, increase in backfat, and reduction in loin muscle area for select line pigs. No differences were found for Hunter L* color, Minolta reflectance, and ultimate pH.

Effects of selenium source and level on growth performance, antioxidative ability and meat quality of broilers

This experiment was conducted to investigate the effects of selenium(Se) source and level on growth performance, carcass traits, antioxidative ability and meat quality of broilers. A total of 320 one-d-old Arbor Acres commercial broilers were randomly assigned to 1 of 5 treatments with 8 replicates in a completely randomized design involving a 2×2 factorial arrangement of treatments plus one Se-unsupplemented basal diet control for 42 d. The two Se sources were sodium selenite and Se yeast, and the two supplemental Se levels were 0.20 and 0.40 mg Se kg^–1. The results showed that broilers fed the Se-supplemented diets had higher(P<0.05) average daily gain and average daily feed intake from 22 to 42 d of age, eviscerated yield and abdominal fat percentages, Se concentrations and glutathione peroxidase(GSH-Px) activities in breast and thigh muscles on d 42, and lower(P<0.05) feed/gain from 1 to 21 and 22 to 42 d of age, mortality from 22 to 42 d of age and malondialdehyde(MDA) concentration in thigh muscle on d 42 than those fed the control diet. Broilers fed the diets supplemented with Se yeast had higher(P<0.05) p H value and lower(P<0.05) shear force in thigh muscle than those fed the diets supplemented with sodium selenite. Additionally, broilers fed the diets supplemented with 0.40 mg Se kg^–1 had lower(P<0.05) shear force in thigh muscle and higher(P<0.05) GSH-Px activities in breast and thigh muscles than those fed the diets supplemented with 0.20 mg Se kg^–1. Furthermore, broilers fed the diet supplemented with Se yeast at 0.40 mg Se kg^–1 had higher(P<0.05) Se concentrations in breast and thigh muscles than those fed the diet supplemented with Se yeast at 0.20 mg Se kg^–1, but no differences(P<0.05) were observed in these indices of broilers fed the diets supplemented with sodium selenite between 0.20 and 0.40 mg Se kg^–1. The results from the present study indicated that supplemental Se could increase the growth performance, muscle Se concentration and antioxidative ability of broilers;and the Se from Se yeast was more effective than the Se from sodium selenite in improving meat quality of broilers.

Wnt gene expression in adult porcine longissimus dorsi and its association with muscle fiber type,energy metabolism,and meat quality

This study investigated the expression profiles of Writ genes in adult porcine Iongissimus dorsi （LD） from different porcine genotypes and their associations with meat quality. The results showed that Wnt5a gene expression level was the highest in Jinhua （JHP） pigs, followed by Zhongbai （ZBP）, DurocxZhongbai （DZB）, and Duroc×Yorkshire×Landrace （DYL） pigs, with significant differences between ZBP, DZB, and DYL （P〈0.05）. This genotypic order was reversed for Wnt7a, Wnt10b, and Wnt11 expression, with JHP and DYL having the lowest and highest expressive levels, respectively. Wnt5a expression was negatively correlated with pH,5 min and ApH （P〈0.01）, some glycolytic markers （P〈0.05）, and positively correlated with meat color （a＊）, shear force （SF） value （P〈0.05）, myosion heavy chain （MyHC） I mRNA proportion （P〈0.01）, turnover ratio of creatine phosphate （CP）, and creatine kinase （CK） activity （P〈0.05）. Opposite correlations were observed for Writ2, Wnt7a, Wnt10b, and Wnt11. These results revealed that Wnt5a, Wnt7a, Wnt10b, and Wnt11 gene expressions in adult porcine muscle contributed to differences between porcine genotypes and affected pork quality. Wnt5a gene expression could be beneficial for the formation of high quality pork by regulating muscle fiber types and postmortem energy metabolism.

Effects of dietary tryptophan and stocking density on the performance,meat quality,and metabolic status of broilers

Background： Highly automated cage-rearing systems are becoming increasingly popular in China. However, a high stocking density can cause oxidative stress and decrease broiler performance. The tryptophan （TRP） derivative 5-hydroxytryptophan （5-HT） has been shown to preserve membrane fluidity in birds suffering from oxidative stress Therefore, this experiment was conducted to determine the effects of dietan/TRP supplementation on performance, breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density. Methods： Female Arbor Acres broilers （25-d-old, n = 144） were randomly allocated to 1 of 4 treatments. The birds were fed a diet based on corn, soybean meal, cottonseed meal and corn gluten meal containing either 0.18 or 0.27% TRP and were housed with stocking densities of 11 or 15.4 birds/m2 in a 2 x 2 factorial experiment. Broiler performance was evaluated from d 25 to 42. Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices. Results： A higher stocking density tended to be associated with reduced weight gain （P 〈 0.10）, and significantly increased plasma glutamic-pyruvic transaminase （GPT） activity （P 〈 0.001）. Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma （P 〈 0.01）, reducing drip loss of breast muscle （P 〈 0.10） and improving feed efficiency （P 〈 0.10）. Conclusions： An increase in dietary TRP, ].S-fold higher than the standard supplementation level, can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.

Effects of Dietary Isoflavone Supplementation on Meat Quality and Oxidative Stability During Storage in Lingnan Yellow Broilers

To investigate the effects of a synthetic isoflavone （SI） on meat quality and oxidative stability, 1 500 43-d-old Lingnan yellow male broilers were randomly assigned to five dietary treatments： diets supplemented with 0, 10, 20, 40, or 80 mg SI kg-1, fed ad libitum for a period of 3 wk. After refrigerated storage, a＊ value of the meat increased with dietary SI supplementation using 10 and 40 mg kg-1 level （P〈0.05）, L＊ value decreased （P〈0.05）, and 40 mg kg-j increased the pH （P〈0.05）. Supplementation with SI, at all levels, increased water holding capacity （P〈0.05） and decreased lactic acid content of meat （P〈0.05）. The concentration of malondialdehyde at 72 h decreased linearly （P=0.005） and quadratically （P=0.004） with increasing levels of SI. Dietary SI at 20 and 40 mg kg-1 levels enhanced total superoxide dismutase activity in meat （P〈0.05）. Meat pH quadratically decreased as the storage time increased （P〈0.05）, with the highest value at 24 h （P〈0.05）. Lactic acid and malondialdehyde concentrations of meat increased over time, with value at 96 h being far higher than at earlier times （P〈0.05）. Supplemental SI linearly and quadratically increased the mRNA abundance ofglutathione peroxidase （GPX） （P=0.001 and P=0.002） and catalase （CAT） （P=0.003 and P=0.006） in breast muscle. The results from this study indicate that dietary supplementation with SI can improve meat quality during refrigerated storage by decreasing lipid peroxidation and enhancing oxidative stability and, for male broilers from 43 to 63 d of age, the optimal level of SI was 40 mg kg-1.

Prediction of meat quality traits in the abattoir using portable near-infrared spectrometers:heritability of predicted traits and genetic correlations with laboratory-measured traits

Background:The possibility of assessing meat quality traits over the meat chain is strongly limited,especially in the context of selective breeding which requires a large number of phenotypes.The main objective of this study was to investigate the suitability of portable infrared spectrometers for phenotyping beef cattle aiming to genetically improving the quality of their meat.Meat quality traits(pH,color,water holding capacity,tenderness)were appraised on rib eye muscle samples of 1,327 Piemontese young bulls using traditional(i.e.,reference/gold standard)laboratory analyses;the same traits were also predicted from spectra acquired at the abattoir on the intact muscle surface of the same animals 1 d after slaughtering.Genetic parameters were estimated for both laboratory measures of meat quality traits and their spectra-based predictions.Results:The prediction performances of the calibration equations,assessed through external validation,were satisfactory for color traits(R^(2) from 0.52 to 0.80),low for pH and purge losses(R^(2) around 0.30),and very poor for cooking losses and tenderness(R^(2) below 0.20).Except for lightness and purge losses,the heritability estimates of most of the predicted traits were lower than those of the measured traits while the genetic correlations between measured and predicted traits were high(average value 0.81).Conclusions:Results showed that NIRS predictions of color traits,pH,and purge losses could be used as indicator traits for the indirect genetic selection of the reference quality phenotypes.Results for cooking losses were less effective,while the NIR predictions of tenderness were affected by a relatively high uncertainty of estimate.Overall,genetic selection of some meat quality traits,whose direct phenotyping is difficult,can benefit of the application of infrared spectrometers technology.

Effects of Nano Chinese Herbal Medicine Feed Additive on Growth Performance,Meat Quality and Disease Resistance of Chickens

[Objectives]To explore the effects of nano compound Chinese herbal medicine feed additive on growth performance,meat quality and disease resistance of chickens.[Methods]Chickens were fed with nano compound Chinese herbal medicine feed additive developed by Hunan Polytechnic of Environment and Biology,including 120 chickens in the treatment group and 120 chickens in the control group(CK).The growth performance indices(body weight gain,feed to gain ratio and slaughter index),meat quality indices(pH value,color,drip loss,shear force)and disease resistance indices(morbidity and mortality)of the chickens in the treatment and CK groups were recorded and determined,respectively.[Results]The inclusion of 2%nano compound Chinese herbal medicine feed additive in the diet significantly increased the growth rate,reduced the feed-to-gain ratio and improved the meat quality of the chickens.Supplementing Chinese herbal medicine could increase the pH value and reduce the drip loss and shear force of chicken meat.At the same time,the body's immune function,antioxidant level and resistance against diseases of the chickens fed with nano compound Chinese herbal medicine feed additive were improved.[Conclusions]The inclusion of nano compound Chinese herbal medicine feed additive in the diet can improve the growth performance,meat quality and disease resistance of chickens.