Dietary supplementation of laminarin improves the reproductive performance of sows and the growth of suckling piglets

Background Maternal nutrition is essential in keeping a highly efficient production system in the pig industry.Laminarin has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the homeostasis of intestinal microbiota.However,the effect of dietary supplementation of laminarin on the reproductive performance of sows and the growth of suckling offspring remains unknown.Methods A total of 40 Landrace×Yorkshire multiparous sows on d 85 of gestation,similar in age,body weight(BW),parity and reproductive performance,were randomly divided into four dietary treatments with 10 sows per treatment,receiving a control diet(basal pregnancy or lactating diets)and a basal diet supplemented with 0.025%,0.05%and 0.10%laminarin,respectively.The experiment lasted from d 85 of gestation to d 21 of lactation.Results Laminarin supplementation linearly increased number born alive per litter(P=0.03),average daily feed intake(ADFI,P<0.01),and total milk yield of sows during the lactation of 1–21 d(P=0.02).Furthermore,maternal laminarin supplementation increased the average daily gain(ADG)of piglets while tending to reduce the culling and death rate before weaning.In addition,alterations to the composition of colostrum and milk,as well as to serum inflammatory cytokines and immunoglobulins of sows were observed.The fecal microbiota profile of sows supported the improvement of reproductive performance in sows and the growth performance in suckling offspring.Conclusions Dietary supplementation of laminarin during late pregnancy and lactation could significantly improve reproductive performance of sows and growth performance of piglets.

Gut microbiota affects the estrus return of sows by regulating the metabolism of sex steroid hormones

Background Sex hormones play important roles in the estrus return of post-weaning sows.Previous studies have demonstrated a complex and bi-directional regulation between sex hormones and gut microbiota.However,the extent to which the gut microbiota affects estrus return of post-weaning sows is largely unknown.Results In this study,we first screened 207 fecal samples from well-phenotyped sows by 16S rRNA gene sequencing and identified significant associations between microbes and estrus return of post-weaning sows.Using metagenomic sequencing data from 85 fecal samples,we identified 37 bacterial species that were significantly associated with estrus return.Normally returning sows were characterized by increased abundances of L.reuteri and P.copri and decreased abundances of B.fragilis,S.suis,and B.pseudolongum.The changes in gut microbial composition significantly altered the functional capacity of steroid hormone biosynthesis in the gut microbiome.The results were confirmed in a validation cohort.Significant changes in sex steroid hormones and related compounds were found between normal and non-return sows via metabolome analysis.An integrated analysis of differential bacterial species,metagenome,and fecal metabolome provided evidence that normal return-associated bacterial species L.reuteri and Prevotella spp.participated in the degradation of pregnenolone,progesterone,and testosterone,thereby promoting estrogen biosynthesis.Furthermore,the microbial metabolites related to sow energy and nutrient supply or metabolic disorders also showed relationships with sow estrus return.Conclusions An integrated analysis of differentially abundant bacterial species,metagenome,and fecal metabolome revealed the involvement of L.reuteri and Prevotella spp.in sow estrus return.These findings provide deep insight into the role of gut microbiota in the estrus return of post-weaning sows and the complex cross-talk between gut microbiota and sex hormones,suggesting that the manipulation of the gut microbiota could be an effective strategy to improve sow estrus return after weaning.

Standardized ileal digestibility of amino acids in soybean meal fed to non-pregnant and pregnant sows

Background Two studies were designed to determine standard ileal crude protein(CP)and amino acid(AA)digestibility of soybean meal(SBM)from different origins fed to non-pregnant and pregnant sows.Seven solvent-extracted SBMs from soybeans produced in the USA,Brazil,and China were selected.In Exp.1,eight different diets were created:a nitrogen(N)-free diet and 7 experimental diets containing SBM from different origins as the only N source.Eight non-pregnant,multiparous sows were arranged in an 8×8 Latin square design(8 periods and 8 diets).In Exp.2,the diet formula was the same as in Exp.1.Eight gestating sows(parity 3)were assigned to 4 different diets in a replicated 4×3 Youden square design(three periods and four diets)in mid-gestation and again in late-gestation stages.Results When fed to non-pregnant and late-gestating sows,the standardized ileal digestibility(SID)of CP and most AAs from different SBM were not significantly different(P>0.05).When fed to mid-gestating sows,the SID values for Arg,His,Lys,Phe,Cys,Gly,Ser,and Tyr in SBM 1 were lower than in SBM 4 and 5(P<0.05),whereas SID for Leu from SBM 5 was higher than in SBM 1 and 4(P<0.05).SID values for Ile,Ala,and Asp from SBM 4 were lower than in SBM 1 and 5(P<0.05).Sows had significantly greater SID values for Lys,Ala,and Asp during mid-gestation when compared with late-gestation stages(P<0.05).Mid-gestating sows had greater SID value for Val and lower SID value for Tyr when compared with non-pregnant and late-gestating sows(P<0.01),whereas non-pregnant sows had significantly greater SID value for Met when compared with gestating sows(P<0.01).Conclusions When fed to mid-gestating sows,the SID values for most AAs varied among SBM samples.The SID values for Lys,Met,Val,Ala,Asp,and Tyr in SBM were affected by sow gestation stages.Our findings provide a cornerstone for accurate SBM use in sow diets.

Effects of improved amino acid balance diet on lysine mammary utilization, whole body protein turnover and muscle protein breakdown on lactating sows

Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.

Current strategies for reproductive management of gilts and sows in North America

Many advances in genetic selection, nutrition, housing and disease control have been incorporated into modern pork production since the 1950s resulting in highly prolific females and practices and technologies, which significantly increased efficiency of reproduction in the breeding herd. The objective of this manuscript is to review the literature and current industry practices employed for reproductive management. In particular the authors focus on assisted reproduction technologies and their application for enhanced productivity. Modern maternal line genotypes have lower appetites and exceptional lean growth potential compared to females of 20 yr ago. Thus, nutrient requirements and management techniques and technologies, which affect gilt development and sow longevity, require continuous updating. Failure to detect estrus accurately has the greatest impact on farrowing rate and litter size. Yet, even accurate estrus detection will not compensate for the variability in the interval between onset of estrus and actual time of ovulation. However, administration of GnRH analogs in weaned sows and in gilts after withdrawal of altrenogest do overcome this variability and thereby synchronize ovulation, which makes fixed-time AI practical. Seasonal infertility, mediated by temperature and photoperiod, is a persistent problem. Training workers in the art of stockmanship is of increasing importance as consumers become more interested in humane animal care. Altrenogest, is used to synchronize the estrous cycle of gilts, to prolong gestation for 2-3 d to synchronize farrowing and to postpone post-weaning estrus. P.G. 600~ is used for induction of estrus in pre-pubertal gilts and as a treatment to overcome seasonal anestrous. Sperm cell numbers/dose of semen is significantly less for post cervical AI than for cervical AI. Real-time ultrasonography is used to determine pregnancy during wk 3-5. PGF2a effectively induces farrowing when administered within two d of normal gestation length. Ovulation synchronization, single fixed-time AI and induced parturition may lead to farrowing synchronization, which facilitates supervision and reduces stillbirths and piglet mortality. Attendance and assistance at farrowing is important especially to ensure adequate colostrum consumption by piglets immediately after birth. New performance terminologies are presented.

Dietary resveratrol improves antioxidant status of sows and piglets and regulates antioxidant gene expression in placenta by Keap1-Nrf2 pathway and Sirt1

Background: Resveratrol, a plant phenol, affords protection against inflammation and oxidative stress. The objective of this study was to investigate the effects of dietary resveratrol supplementation during pregnancy and lactation on the antioxidant status of sows and piglets and on antioxidant gene expression and pathway in placenta.Methods: Forty sows were allotted to 2 dietary treatments 20 d after breeding. Sows were fed a control diet and a control diet with 300 mg/kg resveratrol. Oxidative stress biomarkers and antioxidant enzymes were measured in the placenta, milk, and plasma of sows and piglets. Antioxidant gene expression and protein expression of Kelch-like ECH-associated protein 1-Nuclear factor E2-related factor 2(Keap1-Nrf2), nuclear factor kappa B-p65(NFκB-p65) and sirtuin1(Sirt1) were quantified in the placenta.Results: Dietary resveratrol increased the litter and piglets weaning weights. Antioxidant status in the milk, placenta and plasma of sows and piglets was partially improved by dietary resveratrol. In placenta, Nrf2 protein expression was increased and Keap1 protein expression was decreased by dietary resveratrol. The m RNA expression of antioxidant genes including catalase(CAT), glutathione peroxidase 1(GPX1), GPX4, superoxide dismutase 1(SOD1)and heme oxygenase 1(HO1), and phase 2 detoxification genes, including glutamate-cysteine ligase modifier(GCLM), microsomal glutathione S-transferase 1(MGST1) and UDP glucuronosyltransferase family 1 member A1(UGT1 A1), was increased by dietary resveratrol. Dietary resveratrol also increased Sirt1 and phosphorylated NFκB-p65 protein expression in the placenta. We failed to observe any influences of dietary resveratrol on pro-inflammatory cytokine levels, including those of interleukin 1β(IL-1β), IL-6, IL-8 and tumor necrosis factor α(TNF-α). However, we observed that the m RNA expression of IL-8 in placenta was reduced by maternal resveratrol. In addition, dietary resveratrol showed interactive effects with day of lactation on activities of SOD and CAT and levels of malonaldehyde(MDA) and hydrogen peroxide(H2 O2) in milk.Conclusions: Dietary resveratrol supplementation during pregnancy and lactation improves the antioxidant status of sows and piglets, which is beneficial to the reproductive performance of sows. Dietary resveratrol regulates placental antioxidant gene expression by the Keap1-Nrf2 pathway and Sirt1 in placenta.

Dietary arginine supplementation in multiparous sows during lactation improves the weight gain of suckling piglets

This study investigated the effects of dietary arginine （Arg） supplementation, just during lactation, on sow and litter per- formance, plasma concentrations of metabolites and hormones, and milk yield and composition in multiparous sows. Thirty-one sows were randomly assigned to 3 dietary treatments supplemented with 0.0 （control, n=10）, 0.5% （n=10）, or 1.0% （n=11） L-Arg-HCI, respectively. Experimental diets were provided to the sows from d 3 to 21 of lactation. Plasma and milk samples were collected at d 14 and 21 of lactation. The average daily gain （ADG） of piglets from sows fed diets supplemented with 0.5 or 1.0% L-Arg-HCI at d 3 to 14 of lactation, were higher than that of controls （P〈0.05）. Maternal supplementation with 1.0% L-Arg-HCI also increased ADG of piglets between d 3 and 21 of lactation than that of the controls （P〈0.05）. There was no significant effect of supplementation on average daily feed intake （ADFI）, body weight loss, and backfat thickness loss of lactating sows. Supplementation with 0.5 or 1.0% L-Arg-HCI had a trend towards increasing milk yields and milk fat contents （0.05〈P〈0.10）; milk protein and lactose were unchanged. Supplementation with 1.0% L-Arg- HCI increased plasma concentrations of prolactin and insulin in sows at d 14 and 21 of lactation, and plasma concentrations of non-esterified fatty acid （NEFA）, insulin-like growth factor-1 （IGF-1）, and nitric oxide （NO） in sows at d 21 of lactation, when compared to the controls （P〈0.05）. Supplementation with 1.0% L-Arg-HCI increased IGF-1 and spermine in milk at d 14 of lactation, relative to the controls （P〈0.05）. Plasma Arg concentrations at d 14 and 21 of lactation, as well as plasma NO level and milk IGF-1 at d 21 of lactation, were increased, while plasma urea nitrogen （PUN） concentration at d 14 and 21 of lactation was decreased, by supplementation with 0.5 or 1.0% L-Arg-HCI when compared to the controls （P〈0.05）. Collectively, dietary supplementation of multiparous sows with Arg, just during lactation, is beneficial for enhancing litter weight gain but the complete mechanism remains to be determined and may involve in the maternal endocrine changes and milk polyamines contents.

Heat stress affects fecal microbial and metabolic alterations of primiparous sows during late gestation

Background:Heat stress(HS)jeopardizes intestinal barrier functions and augments intestinal permeability in pigs.However,whether HS-induced maternal microbial and metabolic changes in primiparous sows during late gestation remains elusive.We present here,a study investigating the fecal microbial and metabolic responses in late gestational primiparous sows when exposed to HS.Methods:Twelve first-parity Landrace×Large White F1 sows were randomly assigned into two environmental treatments including the thermoneutral(TN)(18–22℃;n=6)and HS(28–32℃;n=6)conditions.Both treatments were applied from 85 d of gestation to farrowing.The serum and feces samples were collected on d 107 of gestation,for analyses including intestinal integrity biomarkers,high-throughput sequencing metagenomics,short-chain fatty acid(SCFA)profiles and nontargeted metabolomics.Results:Our results show that HS group has higher serum Heat shock protein 70(HSP70),lipopolysaccharide(LPS)and lipopolysaccharide-binding protein(LBP)levels.The gut microbial community can be altered upon HS by usingβ-diversity and taxon-based analysis.In particular,the relative abundance of genera and operational taxonomic units(OTUs)related to Clostridiales and Halomonas are higher in HS group,the relative abundance of genera and OTUs related to Bacteroidales and Streptococcus,however,are lower in HS group.Results of metabolic analysis reveal that HS lowers the concentrations of propionate,butyrate,total SCFA,succinate,fumarate,malate,lactate,aspartate,ethanolamine,β-alanine and niacin,whereas that of fructose and azelaic acid are higher in HS group.These metabolites mainly affect propanoate metabolism,alanine,aspartate and glutamate metabolism,phenylalanine metabolism,β-alanine metabolism,pantothenate and CoA biosynthesis,tricarboxylic acid cycle(TCA)and nicotinate and nicotinamide metabolism.Additionally,correlation analysis between significant microbes and metabolites indicated that the HS-induced microbiota shift is likely the cause of changes of intestinal metabolism.Conclusions:Taken together,we reveal characteristic structural and metabolic changes in maternal gut microbiota as a result of late gestational HS,which could potentially provide the basis for further study on offspring gut microbiota and immune programming.

Effects of magnesium on the performance of sows and their piglets

The objective of this study was to evaluate the effects of supplemental magnesium （Mg） on the performance of gilts and parity 3 sows and their piglets. Fifty-six grits （Trial 1） and 56 sows （Trial 2） were assigned to one of 4 treatments according to their mating weight, respectively. The treatments comprised corn-soybean meal based gestation and lactation diets （0.21% magnesium） supplemented with 0, 0.015, 0.03, or 0.045% Mg from mating until weaning. The results showed that magnesium supplementation significantly （P 〈 0.05） reduced the weaning to estrus interval in both gilts and sows. There were significant effects （P 〈 0.05） of supplemental magnesium on the total number of piglets born, born alive and weaned in sows. In late gestation and lactation, the digestibility of crude fiber （quadratic effects, P 〈 0.05）, and crude protein （P 〈 0.05）, were significantly influenced by magnesium in gilts and sows, respectively. There were differences among the 4 groups in terms of the apparent digestibility of dry matter and crude fiber in sows （P 〈 0.0S） during both early and late gestation. The apparent digestibility of gross energy was increased for sows in late gestation （P 〈 0.05）, and lactation （quadratic effects, P 〈 0.0S）. At farrowing and weaning, serum prolactin levels and alkaline phosphate activities linearly increased in sows as the Mg supplementation increased （P 〈 0.0.5）. Serum Mg of sows at farrowing and serum urea nitrogen of sows at weaning was significantly influenced by Mg supplementation （P 〈 0.05）. The Mg concentration in sow colostrum and the serum of their piglets were increased by supplemental magnesium （P 〈 0.05）. In addition, growth hormone levels were linearly elevated （P 〈 0.05） in the serum of piglets suckling sows. Our data demonstrated that supplemental magnesium has the potential to improve the reproduction performance of sows, and the suitable supplemental dose ranged from 0.015% to 0.03%.

Transcriptome analysis of the effect of pyrroloquinoline quinone disodium（PQQ·Na2） on reproductive performance in sows during gestation and lactation

Background: Pyrroloquinoline quinone(PQQ), which is a water soluble, thermo-stable triglyceride-quinone, is widely distributed in nature and characterized as a mammalian vitamin-like redox cofactor. The objective of this study was to investigate the effects of pyrroloquinoline quinone disodium(PQQ·Na2) on reproductive performance in sows.Results: Dietary supplementation with PQQ·Na2 significantly increased the total number of piglets born, the number of piglets born alive and the born alive litter weight. It also increased the antioxidant status in the placenta, plasma and milk. The concentration of NO was significantly increased in the plasma and placenta. RNA-seq analysis showed that462 unigenes were differentially expressed between the control(Con) treatment and PQQ treatment groups.Among these unigenes, 199 were upregulated, while 263 unigenes were downregulated. The assigned functions of the unigenes covered a broad range of GO categories. Reproduction(27, 7.03%) and the reproduction process(27, 7.03%) were assigned to the biological process category. By matching DEGs to the KEGG database, we identified 29 pathways.Conclusions: In conclusion, dietary supplementation with PQQ·Na2 in gestating and lactating sows had positive effects on their reproductive performance.

Modified halloysite nanotubes reduce the toxic effects of zearalenone in gestating sows on growth and muscle development of their offsprings

Background： Zearalenone （ZEN） is an estrogenic mycotoxin that is primarily produced by Fusarium fungi and has been proven to affect the reproductive capacity of many species to varying degrees. The present experiment was designed to study the maternal persistent effects of zearalenone toxicity in gestating sows on growth and muscle development of their offsprings, and the alleviation of zearalenone toxicity by modified halloysite nanotubes （MHNTs）. Methods： Eighteen sows were fed with one of three dietary treatments that included the following： （1） a control diet, （2） a contaminated grain diet （with 50 % moldy corn, 2.77 mg/kg ZEN）, and （3） a contaminated grain diet （with 50 % moldy corn, 2.76 mg/kg ZEN） ＋ 1% MHNTs. Each sow was exclusively fed its experimental diets from 35 to 70 d of gestation at a total of 2 kg daily. Muscle samples were collected from six piglets per treatment at birth, weaning and finishing. Results： The results showed that feeding the sows with the ZEN-contaminated diets from 35 to 70 d of gestation decreased the ADG, ADFI and G：F of their offsprings （P 〈 0.05）. The muscle fiber numbers in the newborn, weaning and growing-finishing pigs and the muscle fiber diameters at birth and weaning were also decreased by maternal ZEN exposure （P 〈 0.05）. The expressions of IGF-I, IGF-II, Myf-5 and Mstn at birth and IGF-II, Pax7, Myf-5 and MyoD1 at weaning were altered by feeding gestating sows with ZEN-contaminated diets （P 〈 0.05）. The MHNTs reduced most of the ZEN-induced toxic effects： the ADG and ADFI on growth performance, the muscle fiber numbers at weaning and finishing and the muscle fiber diameters at weaning （P 〈 0.05）. The expression levels of IGF-II and Mstn in newborn piglets and IGF-II and Myf-5 in weaning piglets were also prevented by adding 1% MHNTs （P 〈 0.05）. Conclusions： The present study demonstrated that the offsprings of sows fed with ZEN-contaminated diets from 35 to 70 day of gestation exhibited weakening on growth performance, physiological changes in their muscle fibers and alterations of mRNA expression in their muscle tissues, and also indicated that MHNTs prevented most of the ZEN- induced weakening in the muscle tissues.

Inclusion of purified dietary fiber during gestation improved the reproductive performance of sows

Background: This study aimed to investigate the impacts of guar gum and cellulose as the source of dietary fiber during gestation on the reproductive performance of sows.Methods: A total of 210 sows(parities 3–6) were randomly allocated into six diets(n = 35) throughout gestation to feed graded levels of dietary fiber(DF), including a corn-soybean meal-based control diet with no wheat bran inclusion(CON, 12.5% DF), a wheat bran-rich diet(DF1, 17.4% DF), and another 4 diets(DF2, 17.7% DF;DF3, 18.1%DF;DF4, 18.4% DF;DF5, 18.8% DF) in which wheat bran were equally substituted by 1%, 2%, 3% and 4% purified FIBER MIX(guar gum and cellulose, 1:4). All sows received similar DE and other nutrients throughout gestation.Results: DF treatment during gestation resulted in normal fecal score(1 to 5 with 1 = dry and 5 = watery) in sows compared with those received the CON diet(P < 0.05). The number of total born piglets had a tendency to be affected by dietary treatment(P = 0.07), and correlation analysis revealed a linear response of total born to dietary fiber levels during gestation(P < 0.01). Sows received the DF2, DF3, and DF5 diets during gestation had a greater ADFI during lactation compared with those in the CON group(P < 0.05) without affecting the daily body weight gain of suckling piglets. Gut microbiota compositions were dramatically changed by the gestation stage and some of those were changed by DF inclusion. Fecal acetate, propionate, and butyrate of sows were markedly increased in late gestation, and butyrate contents in feces of gestating sows were significantly affected by DF levels(P < 0.01).Serum concentrations of pro-inflammatory TNF-α were decreased and anti-inflammatory IL-10 was increased on day30 of gestation by DF levels(P < 0.05).Conclusions: In summary, increasing dietary fiber levels by guar gum and cellulose during gestation improved the reproductive performance of sows, which might be related to changes in immunity and gut microbiota of sows.

The effect of the ratio of standardized ileal digestible lysine to metabolizable energy on growth performance,blood metabolites and hormones of lactating sows

A total of 335 lactating sows （Landrace x Large White） were used in two experiments to determine the optimum ratio of standardized ileal digestible lysine （SID-Lys） to metabolizable energy （ME） for mixed parity sows during lactation. In Exp. 1, 185 sows （weighing an average of 256.2 ± 6.5 kg and having an average parity of 3.4 ± 0.3） were allocated to one of six experimental diets in a completely randomized block design within parity groups （1, 2, and 3＋）. The experimental diets were formulated to contain 3.06, 3.16, 3.20, 3.25, 3.30 or 3.40 Mcal/kg of ME and each diet was fed to the sows throughout a 28 day lactation. All diets provided a similar SID-lysine level （0.86%）. As a result, the diets provided a SID-Lys：ME ratio of 2.81, 2.72, 2.69, 2.65, 2.61 or 2.53 g/Mcal ME. Sow feed intake was significantly （P 〈 0.01） affected by the energy content of the diet as well as by sow parity. Using regression analysis, feed intake was shown to be maximized at 3.25, 3.21, 3.21 and 3.21 Mcal/kg of ME for parity 1, 2, 3＋ sows and the entire cohort of sows respectively （quadratic; P 〈 0.01）. In addition, the result of feed intake can be expressed as 2.65, 2.69, 2.69 and 2.68 g/Mcal based on analysis of SID-Lys：ME ratio. Litter weight gain was affected by dietary treatment for parity 3＋ sows and the entire cohort （P 〈 0.01）. Based on regression analysis, litter weight gain was maximized at 3.25 and 3.24 Mcal/kg of ME for parity 3＋ （quadratic; P 〈 0.01） and the entire cohort （quadratic; P 〈 0.01）. Similarly, the result of litter weight gain could be expressed as 2.65 and 2.66 g/Mcal of SID- Lys：ME ratio. Therefore, 3.25 Mcal/kg of ME was selected for Exp. 2 in which 150 sows （weighing 254.6 ± 7.3 kg and having an average parity of 3.4 ± 0.4） were allocated to one of five treatments in a completely randomized block design within parity （1, 2, and 3＋）. The experimental diets were formulated to contain 2.1, 2.4, 2.7, 3.0 or 3.3 g/Mcal of SID-Lys：ME ratio with all diets providing 3.25 Mcal/kg of ME. The diets were fed to the sows throughout a 28 day lactation. Sow body weight loss was affected by dietary treatment （parity 3＋ sows, P = 0.02; entire cohort, P 〈 0.01） and by sow parity （P 〈 0.01）. Litter weight at weaning and litter weight gain were affected by dietary treatment for parity 1, 2, 3＋ sows and the entire cohort （P 〈 0.01） as well as by sow parity （P 〈 0.01）. Plasma urea nitrogen （P 〈 0.01）, creatinine （P 〈 0.01） and non-esterifide fatty acids （P = 0.04） were decreased as the SID-Lys：ME ratio of the diet increased. Insulin-like growth factor-1 （P = 0.02）, estradiol （P 〈 0.01） and luteinizing hormone （P = 0.02） were increased as the SID-Lys：ME ratio in diet increased. Based on a broken-line model, the estimated SID-Lys： ME ratio to maximize litter weight gain was estimated to be 3.05 g/Mcal.

Effects of Gamma-Aminobutyric Acid on Performance of Lactating Sows during Heat Weather

[ Objective] To study the effects of gamma-aminobutyric acid （GABA） on performance of lactating sows during heat stress. [ Metbod] A total of 14 sows at the same parity and with close expected date of childbirth and similar body we：,ght were randomly divided into control group and experimental group. They were fed a common basal diet and a GABA （300 mg/kg） supplementary diet, respectively. The trial lasted for 21 d. [ Result ] The daily feed intake, lactation yield and average daily gain of piglets in the experimental group were increased by 9.4%, 28.5% and 10.7%, respectively. The backfat of lactating sows was decreased less, and the same with the weaning-oestrus interval. The survival ratio of piglets was increased by 4.5%. Compared with the control group, the content of lactose and fat increased significantly, but other components almost did not change. [Conclusien] Supplementing GABA in diet can improve the performance of lactating sows and promote the growth of piglets effectively.

Prevalence of Streptococcus suis Isolated from Clinically Healthy Sows in China

Streptococcus suis is an important pathogen in pigs. Transmission of this pathogen is generally believed to occur between healthy carrier sows and their offspring, so the carrier status of S. suis in healthy sows is important for the control of S. suis infections in pigs, especially in suckling and growing pigs. In this study, the prevalence of S. suis isolated from clinically healthy sows in China was studied for the first time. A total of 1 043 tonsil samples were collected from clinically healthy sows from 10 regions in China from 2005 to 2007. Among the 421 S. suis isolates, 31 strains were identified as capsular type 2. The results showed that S. suis was widespread in swine herds in China with the carrier rates in different herds ranging from 19.5 to 93.9%. Overall, 40.4 and 3.0% of clinically healthy sows harbored S. suis and capsular type 2 in their palatine tonsils, respectively. Statistically significant differences of carrier rates of S. suis and capsular type 2 between the different farms were observed, which was independent of herd sizes and geographic distributions of different herds.

Morphological Changes in Hippocampus and Prefrontal Cortex of Confined Sows with Prolonged Pupillary Light Reflex

Human depression patients often show abnormal pupillary reflex with morphological changes in hippo campus and prefrontal cortex. This study aimed to find the relationship between the prolonged pupillary light reflex （PLR） which had been shown by confined sows with chronic stress or depression and morphological changes in brain, in order to provide theoretical basis for that the confined environment should lead to sows＇ depression. A total of 637 sows of Durac, Landrace and Large White breeds with various parities were observed, and the pupil light reflex （PLR） was measured and the actual pupillary light reflex time （PLRT） were recorded. All the PLRTs were grouped based on the results of confidence interval： t〉10% as group A, 5% 〈t〈10% as group B, 1%〈t〈5% as group C and t〈l% as group D. Three individuals were randomly selected from each group （12 sows in total） and the white tissues of hippocampus and the prefrontal cortex were prepared for HS staining slices （three slices/per tissue） for observation on tissue structure and pathological changes with high magnification （400X） of electronic microscope. The results showed that in group A （t〉10%） pathological change was found in hippocampus, however, as PLRT increased from group B to group D, pathological changes in hippocampus tissues tended to be deteriorated with the increase of inflammatory cells and nuclear pyknosis phenomena. The same as those shown in hippocampus as the increasing of PLRT from groups A to D, more inflammatory cells appeared in prefrontal cortex for groups B and D. The results suggested that the tissue lesions of hippocampus and prefrontal cortex of the confined sows with prolonged PLRT might be the results of chronic stress or depression.

Efficacy of Xylooligosaccharides and Probiotics Additive to the Diets of Sows and/or Piglets on Performance,Milk Composition and Appearance of Diarrhea in Sows and Their Offspring

The present study investigated the effects of dietary supplementation of xylooligosaecharides （XOS） and probiotics （PR） on performance, milk compo- sition and diarrhea incidence of sows or their offspring. From day 90 of gestation until weaning, a total of 60 muhiparous sows were randomly assigned to three groups and given three different diets that included either the control diet （ sCON, n = 20 ）, the control diet containing 175 mg/kg XOS （ sXOS, n = 20 ） or 175 mg/kg XOS and 300 mg/kg probiotics （sXOS ＋ PR, n =20）. On day 21 of age, offspring were assigned within sow treatments to the piglet basal diet （pCON） or the piglet basal, diet supplemented with 175 mg/kg XOS （pXOS） for 28 d. Sow feed intake was recorded daily. Body weight and feed consumption of the pigs in each replicate were determined biweekly （on day 0, 14 and 28） to calculate the average daily gain （ADG） of body weight, average daily feed intake （ADFI） and the gain-to-feed ratio （ G： F）. The colostrum and milk samples were obtained on day 0 and 14 of lactation, respectively. Sow XOS or XOS ＋ PR dietary had no effect on the number of total piglets born and born alive and the piglet weight at birth. Milk composition in sow colostrum and milk were not affected by sow diet XOS or （ XOS ＋ PR） supplementation （ P 〉 0.05 ）. No maternal dietary effect was observed on the weaning weight and pre-weaning weight gains of piglets. However, there were interaction effects between sow and piglet dietary treatments on diarrhea rate and diarrhea index during day 35 -49 （P = 0.03 ） and day 21 -49 （P =0.02）. Although sow diet XOS and （XOS ＋ PR ） supplementation did not influence growth performance of weanling piglets, such as ADG and ADFI （ P 〉0.05 ）, piglets XOS supplementation significantly decreased ADFI during the whole experiment period and increased G： F during day 35 -49 and day 21 -49 （ P 〈0.05 ）. These results might suggest that combination of XOS and PR in sow diets had negative impact on the diarrhea incidence of offspring. XOS supplementation in weaned piglet diets decreased ADFI and feed conversion efficiency of weaning piglets.

Impact of sugar beet pulp and wheat bran on serum biochemical profile,inflammatory responses and gut microbiota in sows during late gestation and lactation

Background:Sows are frequently subjected to various stresses during late gestation and lactation,which trigger inflammatory response and metabolic disorders.Dietary fiber can influence animal health by modulating gut microbiota and their by-products,with the effects depending upon the source of the dietary fiber.This study aimed to evaluate the impacts of different fiber sources on body condition,serum biochemical parameters,inflammatory responses and fecal microbiota in sows from late gestation to lactation.Methods:Forty-five multiparous sows(Yorkshire×Landrace;3–6 parity)were assigned to 1 of 3 dietary treatments from d 85 of gestation to the end of lactation(d 21 post-farrowing):a control diet(CON,a corn-soybean meal diet),a sugar beet pulp diet(SBP,20%SBP during gestation and 10%SBP during lactation),and a wheat bran diet(WB,30%WB during gestation and 15%WB during lactation).Results:Compared with CON,supplementation of SBP decreased(P<0.05)lactation BW loss,reduced(P<0.05)serum concentration of total cholesterol,non-esterified fatty acids,interleukin-6 and tumor necrosis factor-α,and increased(P<0.05)fecal water content on d 110 of gestation and d 21 of lactation,while supplementation of WB reduced(P<0.05)serum concentration of total cholesterol on d 110 of gestation,increased(P<0.05)fecal water content and decreased(P<0.05)serum interleukin-6 concentration on d 110 of gestation and d 21 of lactation.In addition,sows fed SBP had lower(P<0.01)abundance of Clostridium_sensu_stricto_1 and Terrisporobacter than those fed CON,but had greater(P<0.05)abundance of Christensenellaceae_R-7_group and Ruminococcaceae_UCG-002 than those fed the other two diets on d 110 of gestation.On d 21 of lactation,supplementation of SBP decreased(P<0.05)the abundance of Firmicutes and Lactobacillus,but enriched(P<0.05)the abundance of Christensenellaceae_R-7_group,Prevotellaceae_NK3B31_group,Ruminococcaceae_UCG-002,Prevotellaceae_UCG_001 and unclassified_f__Lachnospiraceae compared with WB.Compared with CON,sows fed SBP had greater(P<0.05)fecal concentrations of acetate,butyrate and total SCFAs during gestation and lactation,while sows fed WB only had greater(P<0.05)fecal concentration of butyrate during lactation.Conclusions:Supplementation of dietary fiber during late gestation and lactation could improve sow metabolism and gut health,and SBP was more effective than WB.

Effects of the Ratio of n-6∶n-3 Polyunsaturated Fatty Acids in the Maternal Diet on Immunoglobulins,Fatty Acid Composition,and Performance of Lactating Sows and Suckling Piglets under Conditions of Low Maternal Energy Intake

This experiment was conducted to investigate the effects of different ratios of n-6 ∶ n-3 polyunsaturated fatty acids （PUFA） in sow diets on the performance of lactating sows and their piglets at low digestible energy intakes. Twenty-one pregnant Landrace sows were assigned to one of three diets from day 108 of gestation until weaning （26 to 29 d） ,containing n-6∶n-3 PUFA ratios of 3 ∶1,8 ∶1 and 11 ∶1. The effects on sow and litter production traits and on sow body condition were examined. There were no differences among treatments in daily feed intakes or in changes in sow weight and back-fat levels during lactation. Litter size,litter weight at birth and weaning and litter average daily weight gain were also unaffected by treatment. As expected, large differences were observed in n-6 and n-3 fatty acids in the colostrum and plasma of sows and piglets （P 〈 0. 01） . The ratio of n6 ∶ n-3 PUFA the diet was positively correlated with those in colostrum,sow plasma and piglet plasma （R 2= 0. 55,0. 80 and 0. 80,respectively） . Sow plasma insulin and IGF-I levels at weaning were unaffected by the treatments. Plasma leptin （P 〈 0. 05） concentrations were increased in sows fed the diet with a n-6∶n-3 ratio of 8 ∶ 1. Immunoglobulin concentrations in colostrum were not altered by dietary treatment. Plasma IgG concentrations at d 14 were highest in piglets from sows fed the 8 ∶ 1 ratio of n-6∶n-3. Furthermore,this group had the highest IgA concentrations at day 21 of lactation compared with the other two groups （P 〈 0. 05） . In summary,our study demonstrated that at low digestible energy levels,altering the ratio of n-6 ∶ n-3 PUFA in the diets for lactating sows affected immune components and the fatty acid composition of lactating sows and their piglets. Further studies are needed to examine whether higher levels of fat supplementation than those used in the present study （1. 5%） can successfully enhance performance.

Productive and physiological implications of top-dress addition of branched-chain amino acids and arginine on lactating sows and offspring

Background Branched-chain amino acids(BCAAs),including L-leucine(L-Leu),L-isoleucine(L-Ile),L-valine(L-Val),and L-arginine(L-Arg),play a crucial role in mammary gland development,secretion of milk and regulation of the catabolic state and immune response of lactating sows.Furthermore,it has recently been suggested that free amino acids(AAs)can also act as microbial modulators.This study aimed at evaluating whether the supplementation of lactating sows with BCAAs(9,4.5 and 9 g/d/sow of L-Val,L-Ile and L-Leu,respectively)and/or L-Arg(22.5 g/d/sow),above the estimated nutritional requirement,could influence the physiological and immunological parameters,microbial profile,colostrum and milk composition and performance of sows and their offspring.Results At d 41,piglets born from the sows supplemented with the AAs were heavier(P=0.03).The BCAAs increased glucose and prolactin(P<0.05)in the sows’serum at d 27,tended to increase immunoglobulin A(IgA)and IgM in the colostrum(P=0.06),increased the IgA(P=0.004)in the milk at d 20 and tended to increase lymphocyte%in the sows’blood at d 27(P=0.07).Furthermore,the BCAAs tended to reduce the Chao1 and Shannon microbial indices(P<0.10)in the sows’faeces.The BCAA group was discriminated by Prevotellaceae_UCG-004,Erysipelatoclostridiaceae UCG-004,the Rikenellaceae_RC9_gut_group and Treponemaberlinense.Arginine reduced piglet mortality pre-(d 7,d 14)and post-weaning(d 41)(P<0.05).Furthermore,Arg increased the IgM in the sow serum at d 10(P=0.05),glucose and prolactin(P<0.05)in the sow serum at d 27 and the monocyte percentage in the piglet blood at d 27(P=0.025)and their jejunal expression of NFKB2(P=0.035)while it reduced the expression of GPX-2(P=0.024).The faecal microbiota of the sows in Arg group was discriminated by Bacteroidales.The combination of BCAAs and Arg tended to increase spermine at d 27(P=0.099),tended to increase the Igs(IgA and IgG,P<0.10)at d 20 in the milk,favoured the faecal colonisation of Oscillospiraceae UCG-005 and improved piglet growth.Conclusion Feeding Arg and BCAAs above the estimated requirements for milk production may be a strategy to improve sow productive performance in terms of piglet average daily gain(ADG),immune competence and survivability via modulation of the metabolism,colostrum and milk compositions and intestinal microbiota of the sows.The synergistic effect between these AAs,noticeable by the increase of Igs and spermine in the milk and in the improvement of the performance of the piglets,deserves additional investigation.