The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 x 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease （P =0.] O） as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased （P 〈0.0]） when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased （P 〈0.01）. The digestible energy and metabolizable energy content of diets decreased （P 〈0.01） as the total dietary fiber increased.

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.

Predicting corn digestible and metabolizable energy content from its chemical composition in growing pigs

Background： The nutrient composition of corn is variable. To prevent unforeseen reductions in growth performance, grading and analytical methods are used to minimize nutrient variability between calculated and analyzed values. This experiment was carried out to define the sources of variation in the energy content of corn and to develop a practical method to accurately estimate the digestible energy （DE） and metabolisable energy （ME） content of individual corn samples for growing pigs. Twenty samples were taken from each of five provinces in China （Jilin, Hebei, Shandong, Liaoning, and Henan） to obtain a range of quality. Results： The DE and ME contents of the 100 corn samples were measured in 3.5.3 ±1.92 kg growing pigs （six pigs per corn sample）. Sixty corn samples were used to build the prediction model; the remaining forty samples were used to test the suitability of these models. The chemical composition of each corn sample was determined, and the results were used to establish prediction equations for DE or ME content from chemical characteristics. The mean DE and ME content of the 100 samples were 4,053 and 3,923 kcal/kg （dry matter basis）, respectively. The physical characteristics were determined, as well, and the results indicated that the bulk weight and 1,000-kernel weight were not associated with energy content. The DE and ME values could be accurately predicted from chemical characteristics. The best fit equations were as follows： DE, kcal/kg of DM = 1062.68 ＋ （49.72 ×EE） ＋ （0.54 × GE） ＋ （9.1 ] x starch）, with R^2 = 0.62, residual standard deviation （RSD） = 48 kcal/kg, and P 〈 0.01; ME, kcal/kg of dry matter basis （DM） = 671.54 ＋ （0.89 ×DE） - （5.57 × NDF） - （191.39 ×ash）, with R^2 = 0.87, RSD = 18 kcal/kg, and P〈 0.01. Conclusion： This experiment confirms the large variation in the energy content of corn, describes the factors that influence this variation, and presents equations based on chemical measurements that may be used to predict the DE and ME content of individual corn samples.

Effects of the Ratio of Lysine to Digestible Energy Level in the Diet on the Expression and Activity of Transcription Factors Involved in Lipogenesis in Rongchang Pigs

This study was conducted to determine the effects of varying the ratio of lysine to digestible energy level On the activity and gene expression of the transcription factors peroxisome proliferator-activated receptor-γ （PPAR-γ） and CCAAT/enhancer-binding protein-or and -β （C/EBP-α and C/EBP-β） to better understand the regulatory mechanisms controlling adipogenesis in fat and muscle tissue of the Rongchang pig. A total of 144 castrated Rongchang pigs weighing approximately 20 kg were used in a 2 ×2 factorial design experiment. Diets were formulated to contain a high （14.22 MJ/kg） or low （13.11 MJ/kg） digesti- ble energy （DE） level. Within each energy level, pigs were fed diets containing a high lysine： DE ratio （0.67,0. 53, or 0. 42） or a low lysine ： DE ratio （0.49,0.38 ,or 0.30） during the periods from 20 to 50 kg, 50 to 80 kg, and 80 kg to slaughter, respectively. Each diet was fed to six replicate pens, each containing nine pigs. When the pigs reached average live weights of 20,35,60, and 90 kg ,one pig from each of the replicates was chosen at random and slaughtered.Samples of back fat and longissimus dorsi muscle were collected for the assessment of transcriptional factor. The results showed that feeding a high DE level significantly increased （ P 〈 0.05 ） the expression of PPAR-T at 60 and 90 kg in muscle and at 35,60, and 90 kg in back fat. Energy level also significantly increased the expression of C/EBP-fl at 35 and 60 kg in both muscle and back fat （ P 〈 0.05 ）. Higher dieta- ry lysine increased the expression of C/EBP-fl in muscle at 35 and 90 kg （ P 〈 0.05）, but decreased the expression in back fat at 35 （P = 0.03 ） and 90 kg （P = 0.09）. The lysine level increased the expression of PPAR-3~ in muscle at 60 kg only. Energy level and lysine content had no significant effects on promote the activity of PPAR-γ, C/EBP-α, or C/EBP-β either in muscle or in back fat at any level of the body weights tested. Collectively, these data indicated that dietary energy density and lysine level were equally important for lipid deposition in muscle tissue, whereas dietary energy density was more important than lysine level for fat deposition in fat tissue.

Use of near-infrared reflectance spectroscopy for the rapid determination of the digestible energy and metabolizable energy content of corn fed to growing pigs

Background： The ability of near-infrared reflectance spectroscopy（NIRS） to determine the digestible energy（DE）and metabolizable energy（ME） content of corn fed to growing pigs was tested. One hundred and seventeen corn samples, comprising different planting regions and varieties were collected from all over China in a three-year period. The samples were randomly split into a calibration set（n = 88） and a validation set（n = 29）. The actual and calculated DE and ME content of the corn samples was determined by digestion-metabolism experiments and the prediction equations of Noblet and Perez（J Anim Sci. 71：3389–98,1993）. The samples were then subjected to NIRS scanning and calibrations were performed by the modified partial least square（MPLS） regression method based on77 different spectral pre-treatments. The NIRS equations based on the actually determined and calculated DE and ME were built separately and then validated using validation samples.Results： The NIRS equations obtained from actually determined DE, the coefficient of determination for calibration（RSQcal）, cross-validation（R^2CV）, and validation（RSQv） were 0.89, 0.87 and 0.86, and these values for determined ME were 0.87, 0.86 and 0.86. For the NIRS equations built from calculated DE, the RSQcal, R^2CV, and RSQvvalues were 0.88, 0.85 and 0.84, and these values for calculated ME were 0.86, 0.84 and 0.82. Except for the equation based on calculated ME（RPD_v= 2.38, 〈 2.50）, the other three equations built from actually determined energy and calculated DE produced good prediction performance（RPD_vranging from 2.53 to 2.69, 〉 2.50） when applied to validation samples.Conclusion： These results indicate that NIRS can be used as a quantitative method for the rapid determination of the available energy in corn fed to growing pigs, and the NIRS equations based on the actually determined energy produced better predictive performance than those built from calculated energy values.

Net energy of corn,soybean meal and rapeseed meal in growing pigs

Background: Two experiments were conducted to estimate the net energy(NE) of corn, soybean meal, expel er-pressed rapeseed meal(EP-RSM) and solvent-extracted rapeseed meal(SE-RSM) using indirect calorimetry and to validate the NE of these four ingredients using pig growth performance.Methods: In Exp.1, 24 barrows(initial BW = 36.4 ± 1.6 kg) were allotted to 1 of 4 diets which included a corn basal diet,a corn-soybean meal basal diet and two rapeseed meal diets containing 20% EP-RSM(9.5% ether extract) or SE-RSM(1.1% ether extract) substituted for corn and soybean meal. The design allowed the calculation of NE values of corn,soybean meal and rapeseed meals according to the difference method. In Exp.2, 175 growing pigs(initial BW = 36.0± 5.2 kg) were fed 1 of 5 diets for 28 d, with five pigs per pen and seven replications(pens) per treatment in order to validate the measured energy values. Diets were a corn-soybean meal diet and four diets including 10% or 20% EP-RSM and 10% or 20% SE-RSM.Results: The NE of corn, soybean meal, EP-RSM and SE-RSM were 12.46, 11.34, 11.71 and 8.83 MJ/kg DM, respectively. The NE to ME ratio of corn(78%) was similar to tabular values, however, the NE to ME ratios of soybean meal(70%) and rapeseed meal(76%) were greater than tabular values. The greater NE value in EP-RSM than in SE-RSM is consistent with its higher EE content. Increasing EP-RSM or SE-RSM did not affect the growth performance of pigs and the caloric efficiency of NE was comparable for al diets.Conclusions: The NE of EP-RSM was similar to soybean meal, and both were greater than SE-RSM. The DE, ME and NE values measured in Exp.1 are confirmed by results of Exp. 2 with comparable caloric efficiencies of DE, ME or NE for all diets.

Methodologies on estimating the energy requirements for maintenance and determining the net energy contents of feed ingredients in swine:a review of recent work

In the past two decades, a considerable amount of research has focused on the determination of the digestible(DE) and metabolizable energy(ME) contents of feed ingredients fed to swine. Compared with the DE and ME systems, the net energy(NE) system is assumed to be the most accurate estimate of the energy actually available to the animal. However, published data pertaining to the measured NE content of ingredients fed to growing pigs are limited. Therefore, the Feed Data Group at the Ministry of Agricultural Feed Industry Centre(MAFIC) located at China Agricultural University has evaluated the NE content of many ingredients using indirect calorimetry. The present review summarizes the NE research works conducted at MAFIC and compares these results with those from other research groups on methodological aspect. These research projects mainly focus on estimating the energy requirements for maintenance and its impact on the determination, prediction, and validation of the NE content of several ingredients fed to swine. The estimation of maintenance energy is affected by methodology, growth stage,and previous feeding level. The fasting heat production method and the curvilinear regression method were used in MAFIC to estimate the NE requirement for maintenance. The NE contents of different feedstuffs were determined using indirect calorimetry through standard experimental procedure in MAFIC. Previously generated NE equations can also be used to predict NE in situations where calorimeters are not available. Although popular, the caloric efficiency is not a generally accepted method to validate the energy content of individual feedstuffs. In the future,more accurate and dynamic NE prediction equations aiming at specific ingredients should be established, and more practical validation approaches need to be developed.

Effect of variety and drying method on the nutritive value of corn for growing pigs

Background：This experiment was conducted to determine the nutritive value of corn from the north of China for growing pigs.The experiment examined corn variety（LS1,LS2,LS3 and LS4）grown in one location,drying method（sun dried and artificially dried）and different drying temperatures.Corn harvested at 20-25%moisture was dried to about 12%moisture by sun drying and artificially drying at 80,100,or 120℃ in a fluidized bed dryer.Ninety-six barrows（average BW of 33.4 ± 2.7 kg）were housed in individual metabolism crates to facilitate separate collection of feces and urine.A five-day collection period followed a seven-day diet acclimation period.Results：The results indicated that variety significantly influenced（P〈0.01）the 1,000 kernel weight of corn but not the bulk weight.Variety also influenced the available energy content（digestible energy of dry matter,P〈0.01;metabolisable energy of dry matter,P〈0.01）and digestibility of organic matter（P〈0.01）,as well as dry matter（P〈0.01）and gross energy（GE）content（P〈0.02）.The drying method of corn significantly influenced the 1,000 kernel weight（P〈0.01）,bulk weight（P〈0.01）and digestibility of ether extract（EE）（P〈0.01）.No effect of drying temperature on the digestibility of organic matter,dry matter（DM）,crude protein（CP）,neutral detergent fiber（NDF）,acid detergent fiber（ADF）and gross energy was observed,but gelatinization（P〈0.05）and test weight（P〈0.01）decreased with an increase in temperature.Conclusions：Variety has a significant impact on the nutritive value of corn for growing pigs,and greater attention needs to be paid to these influences in the assignment of the nutritive value of corn given to growing pigs.

The Development History of Animal Nutrition and Feed Science in China

Animal nutrition and feed science are the main scientific support for the modern breeding and feed industries. Furthermore, many aspects of biotechnology, information technology, environmental health science, and ecology are involved in the formation and development of these two disciplines.

Foreword for the 11^(th) WCAP Special Issue

The World Conference on Animal Production （WCAP） is recognized as a prestigious industrial meeting by people in the field all over the world. The conference is held every five years, with participants from over eighty countries. The aim of the conference is to retrospect the global trend in animal industry, strengthen the livestock association communication beyond boundaries, and promote the cooperation between researchers and enterprisers over the past five years.

A new start: Journal of Animal Science and Biotechnology re-launches with BioMed Central

Journal of Animal Science and Biotechnology （JASB） was founded in June 2010, as the first English language journal published in the field of animal science in China. The journal is supported by the Chinese Association of Animal Science and Veterinary Medicine, a well-respected and established society. Animal science and animal production have been developing rapidly in China over the past 20 years. China has become the largest meat and egg producer in the world. A group of scientists and researchers have emerged in this fast growing area, pro- ducing high-quality research results.

Metabolic characteristics and nutrient utilization in high-feedefficiency pigs selected using different feed conversion ratio models

An understanding of the nutrient utilization characteristics of pigs with different feed efficiencies(FEs) will help us to develop new strategies to reduce the costs of pig production.In this study,we selected pigs with a range of FEs according to two feed conversion ratio models: the feed intake(FI) model,where pigs had the same average daily gains(ADGs) but different FIs,and the ADG model,where pigs had the same FIs but different ADGs.High-FE pigs had a higher abundance of short chain fatty acid(SCFA)-producing bacteria(Lachnospiraceae,Clostridiaceae1,and Coriobacteriaceae) in their caecum in the FI model,and low-FE pigs had a higher abundance of two families(BacteroidalesS247group and Peptococcaceae) and two genera(Anaerotruncus and CandidatusSoleaferrea) in both models.By contrast,high-FE pigs had more goblet cells and higher m RNA expression of insulin-like growth factor 1(IGF-1) in the FI model,and higher mRNA expression of occludin but lower expressions of adenosine monophosphate-activated protein kinase(AMPK)-α2 and peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC1α) in the ADG model.These findings suggest that the presence of SCFA-producing bacteria in the caecum and increased muscular growth may contribute to the high FE of low-FI pigs,while improved intestinal functions and decreased mitochondrial activity in the skeletal muscle are related to the high FE of high-ADG pigs.

Lipids and membrane-associated proteins in autophagy

Autophagy is essential for the maintenance of cellular homeostasis and its dysfunction has been linked to various diseases.Autophagy is a membrane driven process and tightly regulated by membrane-associated proteins.Here,we summarized membrane lipid composition,and membrane-associated proteins relevant to autophagy from a spatiotemporal perspective.In particular,we focused on three important membrane remodeling processes in autophagy,lipid transfer for phagophore elongation,membrane scission for phago-phore closure,and autophagosome-lysosome membrane fusion.We discussed the significance of the discoveries in this field and possible avenues to follow for future studies.Finally,we summarized the membrane-associated biochemical techniques and assays used to study membrane properties,with a discussion of their applications in autophagy.

Autophagy and the nutritional signaling pathway

During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced,phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo,fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1(unc-51-like kinase 1) and VPS34(which encodes a class III phosphatidylinositol(Ptd Ins) 3-kinase) complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes(ATGs). Amino acid and energy starvation mediate autophagy by activating m TORC1(mammalian target of rapamycin) and AMPactivated protein kinase(AMPK). AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes,ULK1 and VPS34.

Methodological aspects of determining phosphorus digestibility in swine:A review

The role of phosphorus(P) in swine nutrition has been taken on new significance in recent years.Methods to determine the available phosphorus(AP) content of swine feeds include relative bioavailability(RBV), apparent total tract digestibility(ATTD), standardized total tract digestibility(STTD), and true total tract digestibility(TTTD). The RBV of P is determined by measuring bone ash or bone P, whereas the ATTD of P is determined by calculating the difference between P intake and P excretion in feces.Recent research has shown that the use of ATTD of P underestimates the AP due to the existence of endogenous P in feces and digesta. The STTD can be calculated from ATTD by taking basal endogenous phosphorus losses(EPL) into consideration. The basal EPL in pigs can be measured by feeding a P-free diet. Values for STTD of P are believed to be additive in mixed diets but not for ATTD of P. The regression method is a common approach to determine total EPL and TTTD of P, which measures the linear relationship between fecal P excretion and the dietary intake of total P. In addition, in vitro methods such as the bionic enzymatic method are being increasingly utilized because they can be done quickly and simply. Several dietary factors such as P and Ca concentrations, phytate, Ca to P ratio and vitamin D may affect AP. This review summarizes the evolution of methods to measure AP and factors that can affect AP,which may provide information to formulate swine diet more accurately. Moreover, the knowledge about AP may help to reduce the P waste in swine production and thus decrease its impact on the environment.

Light-induced tumor theranostics based on chemical-exfoliated borophene

Among 2D materials(Xenes)which are at the forefront of research activities,borophene,is an exciting new entry due to its uniquely varied optical,electronic,and chemical properties in many polymorphic forms with widely varying band gaps including the lightest 2D metallic phase.In this paper,we used a simple selective chemical etching to prepare borophene with a strong near IR light-induced photothermal effect.The photothermal efficiency is similar to plasmonic Au nanoparticles,with the added benefit of borophene being degradable due to electron deficiency of boron.We introduce this selective chemical etching process to obtain ultrathin and large borophene nanosheets(thickness of ~4 nm and lateral size up to ~600 nm)from the precursor of AlB_(2).We also report first-time observation of a selective Acid etching behavior showing HCl etching of Al to form a residual B lattice,while HF selectively etches B to yield an Al lattice.We demonstrate that through surface modification with polydopamine(PDA),a biocompatible smart delivery nanoplatform of B@PDA can respond to a tumor environment,exhibiting an enhanced cellular uptake efficiency.We demonstrate that borophene can be more suitable for safe photothermal theranostic of thick tumor using deep penetrating near IR light compared to gold nanoparticles which are not degradable,thus posing longterm toxicity concerns.With about 40 kinds of borides,we hope that our work will open door to more discoveries of this top-down selective etching approach for generating borophene structures with rich unexplored thermal,electronic,and optical properties for many other technological applications.

Endogenous chitinase might lead to differences in growth performance and intestinal health of piglets fed different levels of black soldier fly larva meal

This study aimed to investigate the effects of different levels of black soldier fly(BSF)replacing soybean meal(SBM)in diets on the performance and health condition of piglets.A total of 180 weaned piglets were allocated into 5 treatments:BSF0(corn-soybean meal basal diet),BSF25(BSF replacing 25%SBM),BSF50(BSF replacing 50%SBM),BSF75(BSF replacing 75%SBM)and BSF100(BSF replacing 100%SBM).During the whole period,in comparison with BSF0,average daily gain(ADG)and average daily feed intake increased in the BSF25 and BSF50 groups,whereas ADG decreased in the BSF75 and BSF100groups(P<0.05).The result of quadratic fitting curve showed that piglets exhibited the highest ADG when BSF replaced around 20%SBM.Compared with BSF0,organic matter and dry matter digestibility improved in the BSF25 group,whereas ether extract digestibility decreased in the BSF100 group(P<0.05).In comparison with BSF0,piglets from the BSF25 group showed a higher duodenal ratio of villus height to crypt depth,increased jejunal sucrase activity,serum neuropeptide Y and ghrelin levels,elevated ileal immunoglobulin(Ig)A,Ig G and Ig M contents and a lower leptin level,and piglets from the BSF100 group exhibited an increased relative weight of kidney(P<0.05).However,no significant differences were observed in the expression level of tight junction proteins and chitin-degrading enzyme.Additionally,compared with BSF0,the abundance of short chain fatty acid producing bacteria such as Ruminococcaceae,Faecalibacterium and Butyricicoccus increased,and potential pathogenic bacteria decreased in piglets from the BSF25 group,whereas piglets from the BSF100 group had a greater abundance of harmful bacteria.In conclusion,BSF replacing 25%SBM in diets could improve digestive parameters,immune function and intestinal microbiota,and thus improved growth performance of piglets.However,BSF replacing 100%SBM showed an adverse effect on piglet performance,and the reason might be related to the limited amount of chitin-degrading enzyme.

PORK PRODUCTION SYSTEMS IN CHINA:A REVIEW OF THEIR DEVELOPMENT,CHALLENGES AND PROSPECTS IN GREEN PRODUCTION

This paper reviews the changes in pork production in China,the largest pork producing and consuming nation in the world.The pork sector in China has changed dramatically since the 1990s,with large-scale intensive pork production systems replacing the former,exclusively family-based pork production systems.Modern breeding,feeding,vaccinating,and management technologies are widely used now.However,smallholders still account for a large proportion of the total production.The intensification and specialization of the pork sector is expected to continue in the future,but there is increasing awareness and pressure to develop more environmentally-sustainable production systems.The relative shortage of domestically produced feed,the low utilization efficiency of feed ingredients,the large emissions of nitrogen and phosphorus to the environment,the high use of antibiotics,and the presence of residual metals in manures are very large challenges for the pork sector nowadays.To solve these problems,techniques including new feed resource utilization,precise feeding,low-protein diets,alternatives to antibiotics and increased manure recycling are all important topics and research directions today.With new techniques and management approaches,it is possible to build more sustainable pork production systems in China.

Flavor supplementation during late gestation and lactation periods increases the reproductive performance and alters fecal microbiota of the sows

This study was conducted to evaluate the effect of flavor on reproductive performance and fecal microbiota of sows during late gestation and lactation.A total of 20 healthy Yorkshire sows were fed a corn-soybean basal diet unsupplemented or supplemented with 0.1%flavor compound from d 90 of gestation to 25 d post-farrowing,and then the piglets were weaned.The reproductive performance and the fecal microbiota of sows were analyzed.Compared with the controls,flavor supplementation in maternal diets increased(P<0.05)weaning litter weight,litter weight gain,weaning body weight,and average daily gain of piglets.There was a trend of increase in the average daily feed intake of sows(P=0.09)by maternal dietary flavor addition.The backfat thickness and litter size were not affected by flavor supplementation(P>0.05).The 16S rRNA analysis showed that flavor supplementation signifi-cantly increased the abundance of Phascolarctobacterium(P<0.05),but significantly decreased genera Terrisporobacter,Alloprevotella,Clostridium_sensu_stricto_1,and Escherichia-shigella(P<0.05).Spearman correlation analysis showed that Phascolarctobacterum was positively correlated with the average daily feed intake of sows(P<0.05),the litter weight gain and average daily gain of piglets(P<0.05).In contrast,Clostridium_sensu_stricto_1 and unclassified_f__Lachnospiraceae were negatively correlated with the litter weight gain and average daily gain of piglets(P<0.05).Taken together,dietary flavor sup-plementation improved the reproductive performance of the sows,which was associated with enhanced beneficial microbiota and decreased potentially pathogenic bacteria in the sows.