Low crude protein formulation with supplemental amino acids for its impacts on intestinal health and growth performance of growing-finishing pigs

Background Low crude protein(CP)formulations with supplemental amino acids(AA)are used to enhance intestinal health,reduce costs,minimize environmental impact,and maintain growth performance of pigs.However,extensive reduction of dietary CP can compromise growth performance due to limited synthesis of non-essential AA and limited availability of bioactive compounds from protein supplements even when AA requirements are met.Moreover,implementing a low CP formulation can increase the net energy(NE)content in feeds causing excessive fat deposition.Additional supplementation of functional AA,coupled with low CP formulation could further enhance intestinal health and glucose metabolism,improving nitrogen utilization,and growth performance.Three experiments were conducted to evaluate the effects of low CP formulations with supplemental AA on the intestinal health and growth performance of growing-finishing pigs.Methods In Exp.1,90 pigs(19.7±1.1 kg,45 barrows and 45 gilts)were assigned to 3 treatments:CON(18.0%CP,supplementing Lys,Met,and Thr),LCP(16.0%CP,supplementing Lys,Met,Thr,Trp,and Val),and LCPT(16.1%CP,LCP+0.05%SID Trp).In Exp.2,72 pigs(34.2±4.2 kg BW)were assigned to 3 treatments:CON(17.7%CP,meeting the requirements of Lys,Met,Thr,and Trp);LCP(15.0%CP,meeting Lys,Thr,Trp,Met,Val,Ile,and Phe);and VLCP(12.8%CP,meeting Lys,Thr,Trp,Met,Val,Ile,Phe,His,and Leu).In Exp.3,72 pigs(54.1±5.9 kg BW)were assigned to 3 treatments and fed experimental diets for 3 phases(grower 2,finishing 1,and finishing 2).Treatments were CON(18.0%,13.8%,12.7%CP for 3 phases;meeting Lys,Met,Thr,and Trp);LCP(13.5%,11.4%,10.4%CP for 3 phases;meeting Lys,Thr,Trp,Met,Val,Ile,and Phe);and LCPG(14.1%,12.8%,11.1%CP for 3 phases;LCP+Glu to match SID Glu with CON).All diets had 2.6 Mcal/kg NE.Results In Exp.1,overall,the growth performance did not differ among treatments.The LCPT increased(P<0.05)Claudin-1 expression in the duodenum and jejunum.The LCP and LCPT increased(P<0.05)CAT-1,4F2hc,and B0AT expressions in the jejunum.In Exp.2,overall,the VLCP reduced(P<0.05)G:F and BUN.The LCP and VLCP increased(P<0.05)the backfat thickness(BFT).In Exp.3,overall,growth performance and BFT did not differ among treatments.The LCPG reduced(P<0.05)BUN,whereas increased the insulin in plasma.The LCP and LCPG reduced(P<0.05)the abundance of Streptococcaceae,whereas the LCP reduced(P<0.05)Erysipelotrichaceae,and the alpha diversity.Conclusions When implementing low CP formulation,CP can be reduced by supplementation of Lys,Thr,Met,Trp,Val,and Ile without affecting the growth performance of growing-finishing pigs when NE is adjusted to avoid increased fat deposition.Supplementation of Trp above the requirement or supplementation of Glu in low CP formulation seems to benefit intestinal health as well as improved nitrogen utilization and glucose metabolism.

Intrauterine growth restriction alters growth performance, plasma hormones,and small intestinal microbial communities in growing-finishing pigs

Background: The interaction of the gut microbiota with key metabolic and physiological processes may be associated with poor growth outcomes in animals born with intrauterine growth restriction(IUGR).Results: Growth performance, plasma hormone concentrations, and intestinal microbiota composition were analyzed in IUGR pigs and in normal birth weight(NBW) pigs when the NBW pigs reached 25, 50, and 100 kg of body weight(BW). Compared to NBW pigs, IUGR pigs had lower initial, weaned, and final BW, and lower average daily gain and average daily feed intake in all the considered time points. In the 25 kg BW group, IUGR pigs had higher concentrations of plasma ghrelin and pancreatic polypeptide(PP), but lower insulin concentration than NBW pigs, while the situation was reversed in the 50 kg BW group. As compared to NBW pigs, IUGR pigs had higher microbial alpha diversity in the jejunum and ileum;in the 50 and 100 kg BW groups, IUGR pigs had higher Firmicutes abundance but lower Proteobacteria abundance in the jejunum, and lower Lactobacillus abundance in the jejunum and ileum;in the 25 kg BW group, IUGR pigs showed higher unclassified Ruminococcaceae abundance in the ileum;and in 25 and 50 kg BW groups, IUGR pigs showed lower Ochrobactrum abundance in the jejunum.Spearman's correlation revealed that Lactobacillus was negatively correlated with growth performance, while unclassified Ruminococcaceae was positively correlated. Predictive metagenomic analysis detected significantly different expression of genes in the intestinal microbiota between IUGR and NBW pigs, suggesting different metabolic capabilities between the two groups.Conclusions: Growing-finishing IUGR pigs showed lower growth performance, higher microbial alpha diversity, and differences in plasma hormone concentrations compared to NBW pigs. Alterations in the abundance of Firmicutes,Proteobacteria, Ruminococcaceae, Lactobacillus, and Ochrobactrum in the small intestine may be associated with IUGR, and may therefore serve as a future target for gut microbiota intervention in growing-finishing IUGR pigs.

Alterations in intestinal microbiota composition coincide with impaired intestinal morphology and dysfunctional ileal immune response in growing-finishing pigs under constant chronic heat stress

Background:Previous studies had shown that short-term acute heat stress(HS)affected the host’s metabolism and intestinal microbiota independent of feed intake(FI)reduction,and long-term calorie restriction caused intestinal morphological injuries and gut microbial alterations.However,research on the effects of constant chronic HS on intestinal microbial composition and the roles of FI reduction played in is limited.This study aimed to investigate the effects of 7-day constant chronic HS on the composition of intestinal microbes in growing-finishing pigs,and its relationship with pigs’performance,intestinal morphology,and ileal immune response.Twenty-four growingfinishing pigs(Duroc×Large White×Landrace,30±1 kg body weight)were randomly assigned to three treatments(n=8),1)thermal neutral(TN)conditions(25±1℃)with ad libitum FI,2)HS conditions(35±1℃)with ad libitum FI,3)pair-fed(PF)with HS under TN conditions to discriminate the confounding effects of dissimilar FI,and the FI was the previous day’s average FI of HS.The small intestinal segments(duodenum,jejunum,and ileum)and feces were collected on d 8.Results:Results indicated that HS drastically declined(P<0.05)average daily gain(ADG)and average daily feed intake(ADFI)(about 61%)in comparison with TN,and caused hyperpyrexia,meanwhile PF caused hypothermia.Morphological observation by light and electron microscopes showed that both HS and PF treatment decreased(P<0.05)the villus and microvillus height compared with TN.Additionally,HS increased(P<0.05)protein expression of heat shock protein 70 in the duodenum,jejunum,and ileum.Furthermore,the expression of tight junction protein zonula occluden-1(ZO-1)in the duodenum and ileum,and Occludin in the ileum were enhanced(P<0.05)compared with TN and PF.Moreover,HS significantly enhanced(P<0.05)the mRNA relative expression of inflammatory cytokines(TLR-2,TLR-4,and tumor necrosis factor-α(TNF-α),IL-6,IL-8,PG1–5,β-defensin 2(pBD-2)),mucins(mucin-1 and mucin-2)and P65 protein level in the ileal mucosa tissue.Intestinal microbiota analysis by 16S rRNA sequencing showed lower(P<0.10)αdiversity in both HS and PF,and a separated cluster ofβdiversity among groups.Compared with TN,HS but not PF mainly reduced(FDR<0.05)Bacteroidetes(phylum),Bacteroidia(class)and elevated the proportions of Proteobacteria(phylum,FDR<0.05),Bacillales(order,FDR<0.05),Planococcaceae(family,FDR<0.05),Kurthia(genus,FDR<0.05),Streptococcaceae(family,FDR<0.10)and Streptococcus(genus,FDR<0.10).Notably,Lactobacillales(order)was decreased(FDR<0.05)by PF alone.Furthermore,the Spearman correlation analysis indicated that the microbes prevalent in HS were positively(P<0.05)associated with intestinal morphological injuries indicators and ileal immune response parameters,and the microbes reduced in HS were negatively(P<0.05)with the performance data.Conclusions:Intestinal morphological injuries and ileal immune response caused by constant chronic HS independent of FI showed close connections with alterations in intestinal microbiota in growing-finishing pigs.

Effects of dietary protein restriction on muscle fiber characteristics and m TORC1 pathway in the skeletal muscle of growing-finishing pigs

Background： To investigate the effects of dietary crude protein（CP） restriction on muscle fiber characteristics and key regulators related to protein deposition in skeletal muscle, a total of 18 growing-finishing pigs（62.30 ± 0.88 kg）were allotted to 3 groups and fed with the recommended adequate protein（AP, 16 % CP） diet, moderately restricted protein（MP, 13 % CP） diet and low protein（LP, 10 % CP） diet, respectively. The skeletal muscle of different locations in pigs, including longissimus dorsi muscle（LDM）, psoas major muscle（PMM） and biceps femoris muscle（BFM） were collected and analyzed.Results： Results showed that growing-finishing pigs fed the MP or AP diet improved（P 〈 0.01） the average daily gain and feed： gain ratio compared with those fed the LP diet, and the MP diet tended to increase（P = 0.09） the weight of LDM. Moreover, the ATP content and energy charge value were varied among muscle samples from different locations of pigs fed the reduced protein diets. We also observed that pigs fed the MP diet up-regulated（P 〈 0.05） muscular m RNA expression of all the selected key genes, except that myosin heavy chain（My HC） IIb,My HC IIx, while m RNA expression of ubiquitin ligases genes was not affected by dietary CP level. Additionally, the activation of mammalian target of rapamycin complex 1（m TORC1） pathway was stimulated（P 〈 0.05） in skeletal muscle of the pigs fed the MP or AP diet compared with those fed the LP diet.Conclusion： The results suggest that the pigs fed the MP diet could catch up to the growth performance and the LDM weight of the pigs fed the AP diet, and the underlying mechanism may be partly due to the alteration in energy status, modulation of muscle fiber characteristics and m TORC1 activation as well as its downstream effectors in skeletal muscle of different locations in growing-finishing pigs.

Effects of the standardized ileal digestible lysine to metabolizable energy ratio on performance and carcass characteristics of growing-finishing pigs

A total of 2,121 growing-finishing pigs （Duroc × Landrace ×Large White） were utilized in six experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine （SID-Lys） to metabolizable energy （ME） on the performance and carcass characteristics of growing-finishing pigs. Exps. 1 （30 to 50 kg）, 2 （52 to 70 kg） and 3 （81 to 104 kg） were conducted to find an optimum ME level and then this level was used in Exps. 4 （29 to 47 kg）, 5 （54 to 76 kg） and 6 （84 to 109 kg） to test the response of pigs to different ratios of SID-Lys：ME. In Exps.1 to 3, four treatments were used consisting of diets with a formulated ME content of 3.1, 3.2, 3.3 or 3.4 in Exps. I and 2 while Exp. 3 used 3.05, 3.1 S, 3.25 or 3.35 Mcal/kg. A constant SID-Lys：ME ratio of 2.6, 2.3 or 2.0 g/Mcal was used in Exps. 1, 2 and 3, respectively. Weight gain was significantly increased with increasing energy level in Exp.1 while weight gain was unaltered in Exps. 2 and 3. For all three experiments, feed intake was decreased （P 〈 0.05） and feed efficiency was improved （P 〈 0.05） with increasing energy level. Tenth rib back fat thickness linearly increased （P 〈 0.05） with increasing energy level, in Exps. 4 to 6, five treatments were used consisting of diets with a SID-Lys：ME ratio of 2.4, 2.6, 2.8, 3.0 or 3.2 in Exp. 1, 2.1, 2.3, 2.5, 2.7, 2.9 or 3.2 in Exp. 2 and 1.8, 2.0, 2.2, 2.4, or 2.6 in Exp. 3. A constant ME level 3.2, 3.2 and 3.05 Mcal/kg was used in Exps. 1, 2 and 3, respectively （selected based on the results of weight gain）. For all three experiments, weight gain increased （P 〈 0.05） and feed efficiency improved linearly （P 〈 0.05） as the SID-Lys：ME ratio increased. Tenth rib back fat thickness linearly decreased （P 〈 0.0,5） as the SID-Lys：ME ratio increased. Based on a straight broken-line model, the estimated SID-Lys：ME ratio to maximize weight gain was 3.0, 2.43 and 2.2 for 29 to 47, 54 to76 and 84 to 109 kg of pigs, respectively.

Feeding Effect of Growing-Finishing Pigs under Fine Division of Feeding Stages

In order to study the feeding effect of fine division of feeding stages on the growing-finishing pigs,96 healthy Duroc × Landrace ×Yorkshire hybrid commercial pigs with similar age in days,size,and body weight about 15 kg,half boars and half sows,randomly divided into3 treatments( each treatment repeated 4 times,and each repetition 8 pigs). According to the body weight division standard,three stages,four stages,and five stages of feeding were adopted separately. The daily ration of with different nutrition levels was used,body weight and feed consumption were measured,and effects of different feeding methods on body weight increase,feed utilization,and economic benefits of growing-finishing pigs. The results showed that compared with the three-stage feeding,the body weight of five-stage and four-stage feeding increased by 4. 18%( P < 0. 01) and 2. 41%( P < 0. 05),respectively,and the body weight of five-stage feeding increased by 1. 74%( P < 0. 05) compared with that of four-stage feeding; the daily feed consumption of five-stage and four-stage feeding increased 3. 10%( P < 0. 01) and 1. 70%(P <0. 01),respectively,and the daily feed consumption of five-stage feeding was 1. 37% higher than that of four-stage feeding. The feed cost of five-stage feeding and four-stage feeding increased 3. 32%( P < 0. 01) and 1. 61%( P < 0. 05) separately,and the feed cost of five-stage feeding was 1. 69% higher than that of four-stage feeding( P < 0. 01). The income from average body weight increase of five-stage and fourstage feeding increased by 5. 47%( P < 0. 01) and 3. 59%( P < 0. 01) respectively,and the benefit of average body weight increase of fivestage feeding was 1. 81% higher than that of four-stage feeding( P > 0. 05). The crude protein consumption from average body weight increase of five-stage and four-stage feeding decreased by 2. 28%( P < 0. 01) and 1. 68%( P < 0. 01),respectively; the crude protein consumption from average body weight increase of five-stage feeding was 0. 67% lower than that of four-stage feeding; the feed conversion ratio of five-stage feeding,four-stage feeding,and three-stage feeding was 2. 92,2. 93,and 2. 95 respectively. The results showed that compared with the threestage feeding,the four-stage and five-stage feeding could significantly increase the body weight of the growing-finishing pigs,improve the feed utilization level and improve the economic benefits,and the effect of five-stage feeding was better than the four-stage feeding.

Effects of Fermented Nano Chinese Herbal Medicines Replacing Antibiotics on Production Performance and Carcass Quality of Growing-Finishing Pigs

[Objectives]To study the effects of fermented nano Chinese herbal medicines replacing antibiotics on the production performance and carcass quality of growing-finishing pigs.[Methods]200 healthy and disease-free Duroc-Landrace-Yorkshire(DLY)growing-finishing pigs with similar birth time(45±2 d)and body weight of about 31.5 kg were randomly divided into group A(fed with non-antibiotic basal diet),group B(fed with antibiotic basal diet),group C(fed with non-antibiotic basal diet+0.1%fermented nano Chinese herbal medicine preparation),group D(fed with non-antibiotic basal diet+0.3%fermented nano Chinese herbal medicine preparation)and group E(fed with non-antibiotic basal diet+0.5%fermented nano Chinese herbal medicine preparation).The experiment lasted for 90 d.At the end of the experiment,the production performance and carcass indicators were measured.[Results]Compared with group A,the final weight,average daily gain(ADG)and average daily feed intake(ADFI)of groups B,C,D and E were extremely significantly increased(P<0.01),while the feed-to-gain ratio(F/G)was extremely significantly decreased(P<0.01).Compared with group B,the ADG of group E was significantly increased(P<0.05),while the F/G was significantly decreased(P<0.05).Compared with group A,the slaughter rate and carcass length of pigs in groups B,C,D and E were extremely significantly increased(P<0.01);compared with group B,the slaughter rate of groups D and E was extremely significantly increased(P<0.01).[Conclusions]The fermented nano Chinese herbal medicine preparation has better effects in promoting growth than that of antibiotic additives,and it can significantly improve the carcass quality of growing-finishing pigs.

Effects of Probiotics on Growth, Pork Quality and Serum Metabolites in Growing-finishing Pigs

A total of 72 growing-finishing pigs（56 days old） were used to investigate the effects of dietary probiotics on growing performance, pork quality and serum metabolites. Using single factorial experiment design, pigs were allotted to three groups（four pens/group and six pigs/pen）. Diet treatments were a corn-soybean meal（control group） and a corn-soybean meal with 1% probiotics（probiotics group） or 80 mg kg-1colistin sulfate（antibiotics group）. Pigs were slaughtered when pigs of the lightest averaged 90 kg（157 days of age）. There was no difference（p＆gt;0.05） in average daily gain or feed/gain, and the average daily feed intake of the antibiotics group was higher than that of the probiotics and the control groups（p＆lt;0.05）. Diet supplemented with probiotics reduced the drip loss and cooking loss of pork（p＆lt;0.05）. Dietary supplementation with probiotics significantly decreased the content of triglycerides, lowdensity lipoprotein and urea nitrogen in serum（p＆lt;0.05）, and increased the content of high-density lipoprotein in serum（p＆lt;0.05）. These results suggested improving effects of dietary probiotics on pork quality and serum metabolism in growing-finishing pigs.

Effect of different dietary protein levels and amino acids supplementation patterns on growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs

Background:This study was conducted to determine the effects of different dietary protein levels and amino acids supplementation patterns in low protein diets on the growth performance,carcass characteristics and nitrogen excretion in growing-finishing pigs.Forty-two barrows(25.00±0.39 kg)were randomly assigned to 7 diets.Diet 1:the high crude protein diet with balanced for 10 essential amino acids(EAAs).Diet 2:the medium crude protein diet with 2%(approx)decreased protein level of Diet 1 and balanced 10 EAAs.Diet 3:the low crude protein diet with 4%decreased protein level of Diet 1 and balanced 10 EAAs.The protein levels of Diet 4,5,6 and 7 were the same as that of Diet 3.Diet 4 was only balanced for lysine(Lys),methionine(Met),threonine(Thr)and tryptophan(Trp);Diet 5 and 6 were further supplemented with extra isoleucine(Ile)or valine(Val),respectively;Diet 7 was further supplemented with extra Ile+Val.Results:Over the 112 days trial,the reduction of dietary protein by 2%or 4%with balanced10 EAAs significantly decreased nitrogen excretion(P<0.05),but had no effects on growth performance and carcass characteristics(P>0.05).In low protein diet,Val supplementation significantly increased body weight gain at 25–50 kg phase(P<0.05),while Ile supplementation at 75–100 kg phase and 100–125 kg phase significantly reduced the ratio of feed to gain(P<0.05).No effect of different dietary protein levels and amino acids supplementation patterns in low protein diets on carcass characteristics was observed(P>0.05).The total N excretion of pigs supplemented with only Lys,Met,Thr and Trp was numerically higher than that of pigs fed with extra Ile,or Val,or Ile+Val diets.Conclusion:In low protein diet,Val is more required than Ile in the early growing phage(25–50 kg),while Ile becomes more required in the late growing and finishing phage(75–125 kg).

Determination of the available energy values and amino acid digestibility of Flammulina velutipes stem waste and its effects on carcass trait and meat quality fed to growing-finishing pigs

Background:Flammulina velutipes stem waste(FVS)is the by-product of mushroom industry.The objectives of this study were to determine the available energy and amino acid digestibility of FVS fed to pigs,and to evaluate the effects of dietary FVS inclusion on growth performance,biochemical profile of serum,fecal short chain fatty acid(SCFA)concentration,carcass traits,meat quality,intestinal morphology and microflora of pigs.In Exp.1,twelve crossbred barrows with initial body weight(IBW)of 37.48±4.31 kg were randomly allotted to 2 dietary treatments,including a corn basal diet and an experimental diet containing 24.35%FVS.In Exp.2,twelve barrows fitted with an ileal T-cannula(IBW:32.56±1.67 kg)were randomly allotted to 2 dietary treatments,which included a N-free diet and an experimental diet containing 40.0%FVS.In Exp.3,ninety growing pigs(IBW:63.98±6.89 kg)were allotted to 1 of 3 treatment diets for 63 d,including a basal diet and 2 experimental diets with 2.5%and 5%FVS,respectively.Results:The digestible energy(DE)and metabolizable energy(ME)of FVS were 4.58 and 4.06 MJ/kg on dry matter basis,respectively,and the standardized ileal digestibility(SID)of indispensable AAs ranged from 17.50%to 59.47%.Pigs fed diets with 2.5%FVS showed no difference on average daily gain(ADG)and gain to feed ratio(G/F).Although dietary 5%FVS inclusion impaired apparent total tract digestibility(ATTD)of organic matter and gross energy,it elevated the SCFA concentration(P≤0.04)in gut and antioxidant capacity in serum.In addition,dietary FVS inclusion depressed the backfat thickness(P=0.03)in pigs.The longissimus dorsi muscle of pigs fed FVS revealed higher n-3 polyunsaturated fatty acid concentration and optimized fatty acid composition.Dietary 2.5%FVS inclusion also improved the intestinal development and health by increasing the villius height to crypt depth ratio(V/C)in jejunum(P<0.01),and promoting microbial diversity and beneficial microbiota proliferation.Conclusions:It is feasible to include moderate content of FVS as an unconventional fiber ingredient in diet of growingfinishing pigs.

Effects of Dietary Net Energy Density and Standardized Ileal Digestible Lysine: Net Energy Ratio on the Performance and Carcass Characteristic of Growing-Finishing Pigs Fed Low Crude Protein Supplemented with Crystalline Amino Acids Diets

Two 3×3 factorial design trials with 1 080 of Yorkshire×Landrace×Duroc barrows were conducted to investigate the effects of dietary net energy （NE） density and standardized ileal digestible （SID） lysine：NE ratio on the performance of growing- finishing pigs and carcass characteristic of finishing pigs fed low crude protein （CP） supplemented with crystalline amino acids （CAA） diets. Low CP corn-soybean meal basal diets （14% for Exp. 1 and 11% for Exp. 2） supplemented with crystalline lysine, methionine, threonine, and tryptophan were formulated. Nine treatments with increasing NE density and SID lysine：NE ratio were used in each trial （Exp. 1： 9.66, 9.87, and 10.08 MJ kg-1 NE, 0.89, 0.96, and 1.03 g MJ-1 SID lysine： NE; Exp. 2： 9.83, 10.04, and 10.25 MJ kg-1 NE, 0.69, 0.76, and 0.83 g MJ-1 SID lysine：NE）. In Exp. 1, we observed that the average daily gain （ADG） for barrows that received the diet containing 9.87 MJ kg-1 NE was significantly higher than that of barrows fed a 9.66 MJ kg-1 NE diet （P0.05）, but no difference was observed when compared with barrows that received a diet containing 10.08 MJ kg-1 NE （P0.05）. The ADG was affected both linearly （P0.05） and quadratically （P0.05） as the SID lysine：NE ratio increased. The NE density or SID lysine：NE ratio and their interaction had no effect on the average daily feed intake （ADFI） and serum urea nitrogen （SUN） （P0.05）. The feed to gain ratio （F：G） decreased （linearly, P0.05; quadratically, P0.05） as the NE density or SID lysine：NE ratio increased, but no interaction of NE density and SID lysine： NE ratio on the F：G. In Exp. 2, the dietary NE density both linearly （P0.05） and quadratically （P0.05） affected the ADG and F：G. Barrows that received a diet containing 10.04 MJ kg-1 NE had a greater ADG （P0.05） than barrows that received a 9.83 MJ kg-1 diet, but there was no difference （P0.05） as compared with barrows that received a diet containing 10.25 MJ kg-1 NE. F：G was significantly higher （P0.05） for barrows that received a 9.83 MJ kg-1 diet when compared with barrows that received the other two diets. The ADG was significantly decreased （P0.05） for pigs that received a diet containing 0.69 g MJ-1 SID lysine：NE ratio when compared with pigs fed a diet containing 0.76 or 0.83 g MJ-1 SID lysine：NE ratio. The NE density or SID lysine：NE ratio and their interaction had no effect on the average daily feed intake, SUN, and carcass characteristic for finishing barrows （P0.05）. The overall results of the two experiments indicated that barrows that received the diet with the dietary CP level reduced 4 percentage units compared the NRC （1998） recommendations. Maximized the best performance with NE density and SID lysine：NE ratio were 9.87 MJ kg-1, 1.03 g MJ-1 NE for 20-50 kg pigs, and 10.04 MJ kg-1, 0.76 g MJ-1 NE for 60-100 kg pigs, respectively.

Effects of Fermentation Bed Padding on Intestinal Flora,Serum Biochemical Indexes and Immune Function of Growing-finishing Pigs

[Objective]The paper was to study the effects of fermentation bed padding on intestinal flora,serum biochemical indexes and immune function of growing-finishing pigs.[Method]A total of 90 growing-finishing pigs(Duroc × Landrace × Yorkshire)with the body weight of(30.5±0.8)kg were randomly divided into five groups,three replicates each group,six pigs each replicate.The padding of five groups were:50%rice husk+50%sawdust(control group),100%spent mushroom substrate of Pleurotus eryngii(100%spent mushroom substrate group),15%rice husk+15%sawdust+70%spent mushroom substrate(70%spent mushroom substrate group),25%rice husk+25%sawdust+50%spent mushroom substrate(50%spent mushroom substrate group),35%rice husk+35%sawdust+30%spent mushroom substrate(30%spent mushroom substrate group).The pre-trial lasted 7 d,and the formal trial lasted 90 d.[Result]Compared with the control group,the number of Escherichia col in 100%,70%and 50%spent mushroom substrate groups decreased by 35.4%,24.0%and 20.8%,respectively(P<0.05);the number of salmonella successively decreased by 29.4%,19.3%and 15.2%,respectively(P<0.05);the number of lactobacillus successively increased by 21.7%,15.9%and 12.2%,respectively(P<0.05);and the number of bifidobacteria successively increased by 20.2%,16.7%and 11.8%,respectively(P<0.05).Compared with the control group,the total serum protein content in 100%,70%,50%and 30%spent mushroom substrate groups increased by 30.6%,33.0%,28.0%and 18.4%,respectively(P<0.05);and the serum urea nitrogen content decreased by 32.4%,34.5%,33.9%and 22.0%,respectively(P<0.05).There was no significant difference in serum albumin,aspartate aminotransferase(AST)and alanine aminotransferase(ALT)between treatment groups and control group.The IgA,IgG,IgM and IL-6 levels in serum of each treatment group were significantly different from those of the control group(P<0.05).There was no significant difference in IgA,IgG,IgM and IL-6 levels among 100%,70%and 50%spent mushroom substrate groups.[Conclusion]It improves the balance of intestinal microecological flora of growing-finishing pigs and enhances the immune performance of pigs by using spent mushroom substrate of P.eryngii as the fermentation bed padding.15%rice husk+15%sawdust+70%spent mushroom substrate is the optimal proportion of spent mushroom substrate for growing-finishing pigs.

Predicting the growth performance of growing-finishing pigs based on net energy and digestible lysine intake using multiple regression and artificial neural networks models

Backgrounds:Evaluating the growth performance of pigs in real-time is laborious and expensive,thus mathematical models based on easily accessible variables are developed.Multiple regression(MR)is the most widely used tool to build prediction models in swine nutrition,while the artificial neural networks(ANN)model is reported to be more accurate than MR model in prediction performance.Therefore,the potential of ANN models in predicting the growth performance of pigs was evaluated and compared with MR models in this study.Results:Body weight(BW),net energy(NE)intake,standardized ileal digestible lysine(SID Lys)intake,and their quadratic terms were selected as input variables to predict ADG and F/G among 10 candidate variables.In the training phase,MR models showed high accuracy in both ADG and F/G prediction(R^(2)_(ADG)=0.929,R^(2)_(F/G)=0.886)while ANN models with 4,6 neurons and radial basis activation function yielded the best performance in ADG and F/G prediction(R^(2)_(ADG)=0.964,R^(2)_(F/G)=0.932).In the testing phase,these ANN models showed better accuracy in ADG prediction(CCC:0.976 vs.0.861,R^(2):0.951 vs.0.584),and F/G prediction(CCC:0.952 vs.0.900,R^(2):0.905 vs.0.821)compared with the MR models.Meanwhile,the“over-fitting”occurred in MR models but not in ANN models.On validation data from the animal trial,ANN models exhibited superiority over MR models in both ADG and F/G prediction(P<0.01).Moreover,the growth stages have a significant effect on the prediction accuracy of the models.Conclusion:Body weight,NE intake and SID Lys intake can be used as input variables to predict the growth performance of growing-finishing pigs,with trained ANN models are more flexible and accurate than MR models.Therefore,it is promising to use ANN models in related swine nutrition studies in the future.

Effect of Graded Levels of Wheat Distillers Grains with Solubles on Nutrient Digestibility,Performance and Carcass Traits of Growing-Finishing Pigs Fed Diets Based on Wheat and Field Peas

This trial was conducted to determine the effects of graded levels of wheat distillers dried grains with solubles （DDGS） on nutrient digestibility, performance and carcass characteristics of pigs （21.8 to 112.3 kg） fed diets based on wheat and field peas. Forty crossbred pigs were assigned on the basis of sex and weight to one of five dietary treatments in a 5 x 2 （treatment x sex） factorial arrangement. The experimental diets were based on wheat and field peas and were formulated to contain 0, 4.86%, 9.71%, 14.57% or 19.42% wheat DDGS during the growing period and 0, 4.01%, 8.05%, 12.10% and 16.14% wheat DDGS during the finishing period. At the highest levels, ~vheat DDGS supplied 100% of the supplementary protein. The digestibility coefficient for gross energy showed a tendency towards a linear decline （P 〈 0.08 ） as the level of wheat DDGS in the diet increased while digestibility coefficients for dry matter and crude protein were unaffected （P 〉 0. 05 ） by inclusion level of wheat DDGS. During the growing period （21.8 to 60.8 kg）, weight gain of pigs fed wheat DDGS declined （P〈0.01） linearly. The impairment in growth appeared to be associated with a decrease in feed in- take which also declined linearly （P 〈 0.01 ） with increasing inclusion level of wheat DDGS. Feed conversion was unaffected by level of wheat DDGS. During the finishing period （60.8 to 112.3 kg）, and over the entire experimental period （21.8 to 112.3 kg ）, weight gain and feed conversion declined linearly as the dietary inclusion level of wheat DDGS increased. Carcass traits were generally unaffected by the inclusion of wheat DDGS with the exception of a trend towards a linear （P = 0.10） reduction in lean yield and a linear increase （ P = 0.09） in loin fat as the level of wheat DDGS in the diet increased. Overall, these results suggest that wheat DDGS are inferior to field peas as a supplementary protein source for use in swine rations.

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.

Evaluation of the VIUSID Vet (Powder and Solution) Nutritional Supplement in Growing-Finishing Pigs

The objective of this research was to evaluate the impact of the VIUSID Vet(powder and solution)nutritional supplement on the productive performance of growing-finishing pigs.Two experiments were conducted,each using 210 pigs at an average age of 40 d—70 per treatment—which were distributed into 15 pens(five per group).The experiments lasted 170 d.The treatments consisted in:Experiment 1,Group I control group;Group II received from the start 1.5 g of VIUSID Vet powder per kilogram of feed daily for 90 d;Group III same as the former,but instead given 2.0 g.Experiment 2,Group I control;Group II received from the start 1.5 g of VIUSID Vet powder per kilogram of feed daily for 90 d;Group III same as the former,but instead given 1.5 mL of VIUSID Vet solution per kilogram of feed.VIUSID Vet(powder or solution)significantly improved weight gain and feed conversion as well as reduced deaths when given doses of 2.0 g and 1.5 g or 1.5 mL per kilogram of feed during the first 90 d of the growing-finishing phase,giving rise to financial benefits.

Identification of gut microbes associated with feed efficiency by daily-phase feeding strategy in growing-finishing pigs

Feed efficiency is one of the most important issues for sustainable pig production.Daily-phase feeding(DPF)is a form of precision feeding that could improve feed efficiency in pigs.Gut microbiota can regulate host nutrient digestion,absorption,and metabolism.However,which key microbes may play a vital role in improving the feed efficiency during DPF remains unclear.In the present study,we used a DPF program compared to a three-phase feeding(TPF)program in growing-finishing pigs to investigate the effects of gut microbiota on feed efficiency.A total of 204 Landrace×Yorkshire pigs(75 d)were randomly assigned into 2 treatments.Each treatment was replicated 8 times with 13 to 15 pigs per replicate pen.Pigs in the TPF group were fed with a commercial feeding program that supplied fixed feed for phasesⅠ,Ⅱ,andⅢ,starting at 81,101,and 132 d of age,respectively,and pigs in the DPF group were fed a blend of adjacent phase feed from 81 to 155 d at a gradual daily ratio and phaseⅢfeed from 155 to 180 d of age.Daily feed intake and body weight were recorded by a computerized device in the feeders.Feces and blood samples were collected from 1 pig per replicate at 155 and 180 d of age.The results showed that the DPF program remarkably improved the feed efficiency at 155 d(P<0.001)and 180 d of age(P<0.001),with a significant reduction of the intake of crude protein(P<0.01),net energy(P<0.001),crude fiber(P<0.001),ether extract(P<0.01),and ash(P<0.001).The daily-phase feeding program increased the abundance of Prevotella copri(P<0.05)and Paraprevotella clara(P<0.05),while it decreased the abundance of Ocilibacter(P<0.05)at 155 d of age.The results of correlation analysis indicated that the differentially abundant microbiota communities were closely associated with 20 metabolites which enriched amino acid and phenylalanine metabolism.Our results suggest that 2 key microbes may contribute to feed efficiency during daily-phase feeding strategies in pigs.

Dietary supplementation of Lonicera macranthoides leaf powder improves amino acid profiles in serum and longissimus thoracis muscle of growing-finishing pigs

A 60-days feeding trial was conducted to determine the effect of dietary supplementation of Lonicera macranthoides leaf(LML) on growth performance, meat quality, and free amino acid profiles in growingfinishing pigs. L. macranthoides leaves were harvested, air-dried and milled to powder. A total of 288 crossbred barrows(Large White x Landrace) with an average initial BW of 54.0 ± 3.4 kg were randomly allocated to 3 treatment groups and fed either a basal diet or a diet supplemented with 0.5% or 1.0% LML powder. Results showed that diet supplemented with LML powder did not affect average daily feed intake(ADFI) and feed: gain ratio(P> 0.05) in growing-finishing pigs. Moreover, diet supplemented with LML powder showed no significant effects on carcass traits(P > 0.05) including dressing percentage,backfat thickness and loin muscle area, and meat quality traits(P > 0.05) including meat color, intramuscular fat and cooking loss. However, diet supplemented with LML powder significantly improved free amino acid profiles in serum and longissimus thoracis muscle in growing-finishing pigs. Most importantly, dietary LML powder increased total free amino acids content(P < 0.001) and essential free amino acid content(P < 0.001) in longissimus thoracis muscle. These results indicate that LML has the potential to improve the nutritional value of meat through improving free amino acid profiles.

Genetically modified pigs:Emerging animal models for hereditary hearing loss

Hereditary hearing loss(HHL),a genetic disorder that impairs auditory function,significantly affects quality of life and incurs substantial economic losses for society.To investigate the underlying causes of HHL and evaluate therapeutic outcomes,appropriate animal models are necessary.Pigs have been extensively used as valuable large animal models in biomedical research.In this review,we highlight the advantages of pig models in terms of ear anatomy,inner ear morphology,and electrophysiological characteristics,as well as recent advancements in the development of distinct genetically modified porcine models of hearing loss.Additionally,we discuss the prospects,challenges,and recommendations regarding the use pig models in HHL research.Overall,this review provides insights and perspectives for future studies on HHL using porcine models.

Evaluation of the Pharmacological Potential of Strychnos camptoneura Trunk Bark Hydroethanol Extract on Reproductive Functions in Male Guinea Pigs (Cavia porcellus) Exposed to Cypermethrin

The main objective of this study was to evaluate the pharmacological potential of the hydroethanol extract of Strychnos camptoneura trunk bark on reproductive functions in male guinea pigs exposed to cypermethrin. The results showed that administration of the hydroethanolic extract (100 and 250 mg/kg) of Strychnos camptoneura trunk bark after exposure of the animals to cypermethrin induced a highly significant (p Strychnos camptoneura trunk bark produced a highly significant (p Strychnos camptoneura trunk bark may have protective effects against cypermethrin-induced male infertility due to its androgenic, spermatogenic and antiradical properties.