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.

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 high ambient temperature on lipid metabolism in finishing pigs

In this study,we investigated the effects of high ambient temperature on lipid metabolism in finishing pigs.Sixteen pigs（（79.6±1.2） kg） were randomly assigned to two groups：（1） ambient temperature of 30℃ with ad libitum access to feed（HT;n=8） and（2） ambient temperature of 22℃ and fed the average amount consumed by eight pigs in HT group on the previous day（PF;n=8）.After 21 days of constant exposure to different environmental conditions,all the pigs were euthanized,and blood and tissue samples were obtained.High ambient temperature increased the proportion of backfat（P=0.04,＋21.6%）and flare fat（P〈0.01,＋43.3%）.Compared with pair-fed pigs,the activities of fatty acid synthase（FAS） and malic enzyme in backfat and flare fat were lower（P〈0.05） in heat-stressed pigs,as were the amounts of acetyl-CoA-carboxylase and FAS in the longissimus muscle（LM）,the amount of FAS in backfat（P〈0.01）,and FAS activity in the liver（P〈0.01）.Ambient temperature did not affect the amount of hormone-sensitive lipase in different tissues.The amount of lipoprotein lipase in flare fat tended to be higher（P=0.09,＋28.3%）,and the activities of β-hydroxyacyl coenzyme A dehydrogenase in front and back of LM were lower（P〈0.01,-48.3 and-49.8%,respectively） at 30℃ than at 22℃.The plasma concentration of high-density lipoprotein tended to be lower（P=0.08）,but the plasma concentrations of very low-density lipoprotein（VLDL）（P=0.09,＋50.0%） and nonestesterified fatty acid（NEFA）（P=0.04,＋44.2%） were higher in heat-stressed pigs.We concluded that high ambient temperature depressed de novo fatty acid synthesis in both adipose tissues and the liver.However,β-oxidation of fatty acid in skeletal muscles was also inhibited in the high-temperature environment.As a result,more plasma NEFAs were used to synthesize VLDLs in the liver and were absorbed by adipose tissues.This may be one reason that high ambient temperature enhances the accumulation of backfat and flare fat in finishing pigs.

The Influence of Lairage Conditions for Finishing Pigs on Behavior,Biochemical Indicators and Meat Quality

A total of 60 crossbred(Large White×Landrace) pigs of halothane genotype NN(castrated males and females) were allotted to three treatments:3 h lairage with toys,3 h lairage and 0 h lairage in a randomized complete block design and used to evaluate the influence of lairage conditions on behavior, biochemical indicators and meat quality for finishing pigs at slaughter.Behavior of the pigs was scored subjectively during lairage.Blood samples were taken at exsanguination s to measure blood temperature, plasma Cortisol,ACTH,glucose,lactate,plasma enzymes and hematological indices.Post-mortem meat quality measurements included muscle colour value(MCV),electrical conductivity(EC),pH at 45 min and 24 h from Longissimus thoracis(LM) and Semimembranosus(SM) mucles and drip loss from LM. The results showed that 3 h lairage group with toys demonstrated significantly improved behavior than the group without toys at 3 sampling times.All the pigs showed increasing calmness as the time of lairage progressed.The omission of lairage increased plasma Cortisol,ACTH,glucose and lactate(P【0.05),and decreased plasma lactate dehydrogenase(LDH),and creatine kinase(CK)(P【0.05).No biochemical index was influenced by the presence or absence of toys during lairage(P【0.05).Muscle colour value, electrical conductivity,pH at 45 min and 24 h from LM and SM and drip loss were not affected by any treatment(P【0.05).Pigs provided 3 h lairage,with or without toys,exhibited lower red blood cell(RBC), hemoglobin(HGB),and haematocrit(HCT) when compared to 0 h lairage.3 h lairage with or without toys resulted in higher white blood cell(WBC) and lymphocyte(W-SCC) levels than 0 h lairage.None of the hemocytic indices in pigs given lairage was affected by the presence or absence of toys.We conclude from this pilot study that in local commercial conditions,from the point of view of animal welfare and meat quality,lairage time of 3 h after short travel was beneficial.Pigs resting showed increased relief from stress and a recovery in immune competence.Holding pigs in lairage with toys for a few hours after arrival at the abattoir may be beneficial for the animal’s well-being.

Effects of dietary energy density on plasma glucose and lipid profile,morphological aspects and chemical characteristics of adipose tissue in finishing pigs

ABSTRACT： Peroxisome proliferator-activated re- ceptor-Υ （PPAR-T） plays a pivotal role in controlling adipogenesis. We hypothesized that changes in dietary energy density might alter fat deposition in finishing pigs via modulation of the expression of PPAR-Υ . To test this hypothesis, thirty female finishing pigs were fed diets containing low （ LD ）, medium （ MD ） or high （HD） energy density. Blood samples were col- lected on day 53, and then the pigs were sacrificed to collect samples of the dorsal subcutaneous （ ST）, ab- dominal （AT） and mesenteric （MT） adipose tissue. Compared with pigs fed the MD diet, malate dehydro- genase activity was increased in the ST and MT of pigs fed the HD diet, while activity was decreased in the MT of pigs fed the LD diet （P 〈 0.05）. Glucose- 6-phosphate dehydrogenase activity was increased in all three fat depots of pigs fed the HD diet （P 〈0.05） in comparison with pigs fed the MD diet. Both HD and LD diets increased the size of the adipocytes in the AT and MT （ P 〈 0.05 ）. Pigs fed the HI） diet had a higher cell proliferation index in the ST com- pared with pigs fed the other two diets （P 〈 0.05 ）. Compared with pigs fed the MD diet, a decreased ap- optosis index was seen in the ST of pigs fed the HD diet, and in the AT of pigs fed the LD diet, as well as in the MT of both HD and LD fed pigs （ P 〈 0.05）. PPAR-Υ positive percentage was elevated in the ST and MT of HD fed pigs compared with pigs fed the MD and LD diets, while it was decreased in the ST of LD compared with MD fed pigs （ P 〈 0.05 ）. These results suggest that dietary energy density may regu- late fat deposition in fmishing pigs. It is possible that feeding a high energy diet may induce fat deposition via up-regulation of PPAR-Υ expression.

Effects of Low Protein Diets on Nutrient Digestibility and Excretion in Finishing Pigs

The experiment was conducted to study the effects of low protein diets on nutrient digestibility and excretion of finishing pigs. For the 30-d trial,fortytwo duroc × landrace × yorkshire( DLY) finishing pigs with the initial weight of( 91. 13 ± 1. 64) kg were randomly divided into two groups,with three replicates in each group. The pigs in the two groups were fed with different crude protein( CP) levels( control groups: 15. 49% and low protein groups: 12. 59%). The results showed that:( 1) The digestibility of dry matter and crude fat( CF) in low protein groups were increased significantly( P < 0. 01),but there were no significant differences in digestibility among CP,calcium( Ca) and phosphorus( P);( 2) The digestibility of arginine( Arg) in low protein groups were 2. 02%( P <0. 05) lower than that in control groups. However,the digestibility of other amino acid were no difference between two groups;( 3) The nitrogen( N) excretion in low protein groups was 23. 96%( P < 0. 05) lower than that in control groups,but there were no significant differences in excretion among organic matter,P and Ca( P > 0. 05). The results showed that 2. 9% reduction of the CP in diets could improve nutrient digestibility and reduce the excretion of N,but reduced the digestibility of Arg.

Effects of Fermented Forage with Highly Active Bacteria on Immunity and Oxidation Resistance of Growing-finishing Pigs

[Objective]The aim was to study on effects of fermented forages with highly active bacteria on immunity and oxidation resistance of fin- ishing pigs,providing references for popularization and application of the forage. [Method]About 180 duroc-landrace-yorkshire swines at the same age were chosen and two groups were set. In control group,the pigs were fed with basic forages and antibiotics,and in test group,the pigs were fed with basic forages and 8% of forages with highly active bacteria. [Result] Compared with control group,immune globulins in test group im- proved significantly and IgG differed extremely on the 28th d （ P 〈0. 01） ; blocking rate of antibody against swine fever enhanced by 46. 10% on the 28th d than that on the 21th d with significant differences （ P 〈0. 05） ; oxidation resistance in test group was significantly higher and T-AOC achieved an extreme level （ P 〈0. 01） . [Conclusion]Forages with highly active bacteria would promote immunity and oxidation resistance of finishing pigs, which is of great value in production.

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.

Effects of main active components of rosemary on growth performance,meat quality and lipid metabolism in finishing pigs

Rosemary extracts have been widely used as feed additives in recent years.This study aimed to investigate the effects of rosmarinic acid(RA)and ursolic acid(UA),the main active components of rosemary,on growth performance,meat quality and lipid metabolism in finishing pigs.A total of 72 finishing pigs(Landrace;initial age of 150 d)were randomly divided into 3 treatments with 8 replicates of 3 pigs each,and fed a basal diet or diet containing 500 mg/kg of RA or UA.The results showed that dietary supplementation of RA or UA had no significant effect on the growth performance and carcass traits of finishing pigs(P>0.05).However,both RA and UA significantly increased the triglyceride(TG)level in soleus muscle(P<0.001).Supplementation of RA increased the expression of genes related to lipogenesis and transport including fatty acid synthase(FAS)(P<0.001),sterol regulatory element binding protein-1c(SREBP1c)(P<0.001)and peroxisome proliferator-activated receptorγ(PPARγ)(P<0.05),while UA increased the expression of fatty acid transport protein 1(FATP1),a gene related to lipid uptake(P<0.05).However,RA reduced the expression of adipogenesis-related gene acetyl-coenzyme A carboxylase a(ACCa)(P<0.01).Characterization of cecal microbiota indicated that RA increased the microbial richness(chao 1,P<0.001)and diversity(observed species,P<0.01).Further analysis of the genera revealed that RA increased the relative abundance of Bacteroides and g-UCG-005(P<0.05),and UA enriched Prevotella(P<0.001).Correlation analysis showed that g-UCG-005 was positively correlated with the expression of FAS,carnitine palmitoyl transferase 1B(CPT1B),SREBP1c and PPARγ(P<0.01).In conclusion,dietary supplementation of RA or UA may increase fat deposition in muscle of finishing pigs by regulating lipid metabolism and gut microbiota.

Effects of the ratio of unsaturated fatty acid to saturated fatty acid on the growth performance,carcass and meat quality of finishing pigs

The effects on finishing pigs(80-100 kg BW) fed diets supplemented with oil sources containing different ratios of unsaturated to saturated fatty acids(UFA:SFA ratio) were evaluated in 15 barrows and15 gilts(Duroc × Large White × Landrace). Three experimental diets were evaluated using a randomized complete block design, with broken rice, soybean meal and rice bran as the main feedstuffs in the control diet. Diets 2 and 3 consisted of the control diet supplemented with 3% oil, with UFA:SFA ratios of 2.5:1 and 5:1, respectively. Overall, there was no significant difference(P> 0.05) found in the average daily gain(ADG) of the pigs fed the treatment diets; however, the pigs fed the control diet and diet 3 had better(P < 0.05) feed conversion ratios(FCR) than the pigs fed diet 2. The pigs fed diets 2 and 3, which were supplemented with oil at UFA:SFA ratios of 2.5:1 and 5:1, had greater(P < 0.05) average daily feed intakes(ADFI) than the pigs in the control group. Additionally, it was found that the gender of the pigs had an effect(P < 0.05) on the FCR. Interaction effects between the experimental diets and the gender of the pigs(P < 0.05) were found in the ADFI and FCR. There were no significance differences(P > 0.05)among the treatment groups with regard to the carcass quality of the pigs; however, it was found that the gilts had greater(P < 0.01) loin eye areas than the barrows fed diets 2 and 3 and the loin eye area of pig fed diet 2 was the largest(P < 0.05); In the case of the meat quality parameters, it was clearly found that the pigs fed the control diet had a greater(P < 0.05) lightness(L~*) in the meat colour, and the lowest cooking loss was found in the pigs fed the diet supplemented with fat containing the UFA:SFA ratio of 5:1.Overall, the dietary treatment did not significantly affect the drip loss, thawing loss and shear force of the pork. In conclusion, the supplementation of oil with UFA:SFA ratios of 2.5:1 and 5:1 has the potential to improve pork quality.

Effect of dietary supplementation with sugar cane extract on meat quality and oxidative stability in finishing pigs

The aim of the present study was to investigate the effect of dietary supplementation with sugar cane extract(SCE) on meat quality and oxidative stability of Longissimus dorsi muscle in finishing pigs.Eighteen barrows(Duroc × Landrace × Jiaxing Black), with an average initial body weight of 62.1 ± 5.0 kg,were randomly allotted to 1 of 3 diets with 6 replicates per treatment for 42 days. The diets comprised a normal diet and the normal diets supplemented with 5 and 25 g/kg SCE. The results showed that SCE supplementation did not affect final body weight of finishing pigs. Dietary SCE supplementation significantly increased(P < 0.05) Longissimus dorsi muscle pH_(24 h),and tended to reduce(P < 0.1) and significantly decreased(P < 0.05) shear force, drip loss, myofiber cross sectional area and lactate dehydrogenase activity at 5 and 25 g/kg, respectively. Meanwhile, dietary SCE treatments significantly decreased(P < 0.05) malonaldehyde content and total superoxide dismutase activity in Longissimus dorsi muscle, and tended to reduce(P < 0.1) malonaldehyde content in serum. Altogether, these data indicate that SCE is an effective feed additive to improve pork meat quality, and the underlying mechanism may be partly due to the improved oxidative stability induced by dietary SCE supplementation.

Dietary lycopene supplementation improves meat quality,antioxidant capacity and skeletal muscle fiber type transformation in finishing pigs

This study aimed to investigate effects of dietary lycopene supplementation on meat quality,antioxidant ability and muscle fiber type transformation in finishing pigs.In a 70-day experiment,18 DurocLandraceYorkshire barrows were randomly allocated to 3 dietary treatments including a basal diet supplemented with 0,100 and 200 mg/kg lycopene,respectively.Each dietary treatment had 6 replicates with one pig each.Results showed that dietary 200 mg/kg lycopene supplementation increased muscle redness a^(*)value,intramuscular fat and crude protein contents,and decreased muscle lightness L^(*)and yellowness b^(*)values(P<0.05),suggesting that addition of 200 mg/kg lycopene to the diet of finishing pigs improved color,nutritional value and juiciness of pork after slaughter.Results also showed that dietary lycopene supplementation enhanced antioxidant capacity of finishing pigs(P<0.05).Moreover,dietary supplementation of 200 mg/kg lycopene significantly increased slow myosin heavy chain(MyHC)protein level and slow-twitch fiber percentage,and decreased fast MyHC protein level and fast-twitch fiber percentage(P<0.05),suggesting that the addition of 200 mg/kg lycopene to the diet of finishing pigs promoted muscle fiber type conversion from fast-twitch to slow-twitch.Together,we provide the first evidence that dietary 200 mg/kg lycopene supplementation improves meat quality,enhances antioxidant capacity and promotes muscle fiber type transformation from fast-twitch to slow-twitch in finishing pigs.

Prevotella-rich enterotype may benefit gut health in finishing pigs fed diet with a high amylose-to-amylopectin ratio

To investigate the influence of baseline enterotypes and dietary starch type on the concentration of short-chain fatty acids(SCFA),numbers of butyrate producing bacteria and the expression of genes related to intestinal barrier and inflammatory response in the colon of finishing pigs,a 60-d in vivo trial was conducted.A 2-wk pre-trial with 102 crossbred(Duroc×[Landrace×Yorkshire])finishing barrows(90 d old)was conducted to screen enterotypes.Then,a total of 32 pigs(87.40±2.76 kg)with high(HPBR,>14)and low(LPBR,<2)Prevotella-to-Bacteroides ratios(PBR)in equal measure were selected and randomly divided into 4 groups with 8 replicates per group and 1 pig per replicate.The trial was designed following a 2(PBR)×2(amylose-to-amylopectin ratio,AMR)factorial arrangement.Pigs with different PBR were fed diets based on corn-soybean meal with high AMR(HAMR,1.24)or low AMR(LAMR,0.23),respectively.Results showed that neither PBR nor AMR influenced the growth performance of pigs.HPBR pigs fed HAMR diet had a higher number of colonic Clostridium cluster XIVa and higher gene expression of butyrate kinase compared to the LPBR pigs(P<0.05).The HPBR pigs fed HAMR diets also had increased colonic concentrations of total SCFA and propionate compared to the LPBR pigs(P<0.05).Comparing with other pigs,HPBR pigs fed HAMR diets showed a lower(P<0.05)expression of histone deacetylases(HDAC)gene and higher(P<0.05)expression of G protein-coupled receptor 43 gene(GPR 43)in the colonic mucosa.The interaction(P<0.05)of HPBR and HAMR was also found to decrease the gene expression of interleukin(IL)-6,IL-12,IL-1βand tumor necrosis factor-α(TNF-α)in colonic mucosa.These findings show that HAMR diet increased the abundance and activity of butyrate-producing bacteria and the concentration and absorption of SCFA,which may be associated with the decreased gene expression of inflammatory cytokines in the colonic mucosa of pigs with Prevotella-rich enterotype.All these alterations are likely to have a positive effect on the intestinal health of finishing pigs.

Co-fermented defatted rice bran alters gut microbiota and improves growth performance,antioxidant capacity,immune status and intestinal permeability of finishing pigs

Based on preparation of co-fermented defatted rice bran(DFRB)using Bacillus subtilis,Saccharomyces cerevisiae,Lactobacillus plantarum and phytase,the present study aimed to evaluate the effects of cofermented DFRB on growth performance,antioxidant capacity,immune status,gut microbiota and permeability in finishing pigs.Ninety finishing pigs(85.30±0.97 kg)were randomly assigned to 3treatments(3 replicates/treatment)with a basal diet(Ctrl),a basal diet supplemented with 10% unfermented DFRB(UFR),and a basal diet supplemented with 10% fermented DFRB(FR)for 30 d.Results revealed that the diet supplemented with FR notably(P<0.05)improved the average daily gain(ADG),gain to feed ratio(G:F)and the digestibility of crude protein,amino acids and dietary fiber of finishing pigs compared with UFR.Additionally,FR supplementation significantly(P<0.05)increased total antioxidant capacity,the activities of superoxide dismutase and catalase,and decreased the content of malonaldehyde in serum.Furthermore,FR remarkably(P<0.05)increased serum levels of Ig G,antiinflammatory cytokines(IL-22 and IL-23)and reduced pro-inflammatory cytokines(TNF-α,IL-1β and INF-γ).The decrease of serum diamine oxidase activity and serum D-lactate content in the FR group(P<0.05)suggested an improvement in intestinal permeability.Supplementation of FR also elevated the content of acetate and butyrate in feces(P<0.05).Moreover,FR enhanced gut microbial richness and the abundance of fiber-degrading bacteria such as Clostridium butyricum and Lactobacillus amylovorus.Correlation analyses indicated dietary fiber in FR was associated with improvements in immune status,intestinal permeability and the level of butyrate-producing microbe C.butyricum,which was also verified by the in vitro fermentation analysis.These findings provided an experimental and theoretical basis for the application of fermented DFRB in finishing pigs.

Different copper sources and levels affect growth performance,copper content,carcass characteristics,intestinal microorganism and metabolism of finishing pigs

Copper(Cu)is an essential trace element in the production of swine.This study was conducted to investigate the effect of 3 different sources of Cu on growth performance,Cu metabolism,and intestinal microorganisms of finishing pigs,so as to estimate the bioavailability of the 3 sources for pigs.A total of 42 male finishing pigs(88.74±5.74 kg)were randomly allocated to 7 treatments.The factors were 3 sources(CuSO4,Cu-glycine,Cu-proteinate)and 2 levels(5 and 20 mg/kg)of Cu,plus one negative control treatment(0 mg/kg added Cu level)for the entire 28-d experiment.The average daily gain(ADG)and feed to gain ratio(F:G)both increased when Cu was added.The Cu level in liver,bile,kidney,serum,lung,urine and feces rose(P<0.001)with increasing dietary Cu level regardless of the source.Meanwhile,pigs receiving organic Cu(glycinate or proteinate)retained more Cu and excreted less Cu than those receiving inorganic Cu(CuSO4),which showed that organic forms were more bioavailable.At the transcriptional level,changes in the level and source of dietary Cu resulted in modulation of transporters.In the jejunal mucosa,import transporter high affinity copper uptake protein 1(CTR1)and export transporter ATPase copper transporting alpha(ATP7A)in supplemental Cu treatments were down-regulated compared to the control.Also,peptide transporter 1(PepT1)and lanine-serine-cysteine transporter,type-2(ASCT2)were significantly(P<0.01)up-regulated in 20 mg/kg Cu-proteinate and Cu-glycinate treatments,respectively.Microbial diversity was lowest in the 20 mg/kg CuSO4 treatment,and the ratio of Firmicutes to Bacteroidetes was higher in added Cu treatments,especially Cu-glycinate treatment.These results indicate that uptake of different Cu forms is facilitated by different transporters and transport mechanisms,and compared with inorganic Cu,organic Cu provides benefits to intestinal microflora and reduces Cu excretion.

Effects of Low Protein Diets Supplemented with Ami-no Acids on Production Performance,Carcass Qual-ity and Input-output Ratio of Pigs

[ Objectives ] To study the effects of low-protein diets supplemented with amino acids on the production performance, carcass quality and input-output ratio of fattening pigs and growing-finishing pigs. [ Methods] Two studies were conducted on fattening pigs and growing pigs respectively. Pigs in two experimental groupswere fed with low-protein diets supplemented with amino acids and normal diets respectively, and the initial weight, final weight, feed consumption and car- cass index of the tested pigs were measured. [ Results] The average final weight of fattening pigs in test group was 2.4 kg lower than that in control group, while the difference was not significant （P 〉 0.05 ）. The average daily gain of fattening pigs in test group was 60 g lower than that in control group, indicating that low protein diets had a tendency to decrease the growth rate （P 〉 0.05 ）, and reduction of daily weight gain in low protein diet pigs reached 7.6%. The development of pigs in low protein diet group was poor, however, the difference was not significant. Carcass backfat thickness in low-protein diet group was slightly higher than that in control group, the difference was significant （ P 〈 0.05 ）. There was no significant difference in input-output ratio between low-protein diet group and control group. Finalweight of growing-finishing pigs in low-protein diet group was 3.22 % lower than that in control group, the average daily weight gainwas 6.91% lower than that in control group, feed intake in test group was 5.48% lower than that in control group, and difference between the two treatments was significant （P 〈 0.05 ）. Feed meat ratio in low-protein diet group improved, however, the difference was not significant（P 〉0.05）. [ Conclusions] Production performance of the pigs would be decreasedand the input-output ratio could not be improvedwhen the adding contents of crude protein in diets was reduced 3% -4%. Therefore, it is recommended that the crude protein level should be enough when pigs were fed with low-protein diets.