低蛋白日粮平衡氨基酸对生长猪生产性能的影响

本试验旨在研究低蛋白日粮平衡氨基酸对生长猪生长性能的影响.试验选取健康状况良好,胎次相近,平均体重(31.06±2.05kg)的杜长大三元杂交商品猪18头,随机分为3个处理,每个处理6个重复,每个重复1头猪,单笼饲养.对照组饲喂18％CP日粮、试验组在对照组基础CP依次降低2％和4％,即16％CP和14％CP,并添加相...     

低蛋白日粮对生长猪及育肥猪的影响

选取初始体重为25kg的杜×大×长三元健康生长猪176头及初始体重为50kg的杜×大×长三元健康中猪144头,采用单因子设计,分为对照组和试验组;对照组中日粮按照NRC（1998）营养需要量推荐配制,试验组在NRC推荐的日粮粗蛋白水平上降低4个百分点探讨低蛋白日粮对生长猪和育肥猪生长性能的影响。结果表明：生长猪试验组日增重比对照组增加了46g,提高幅度为6．82％;料肉比比对照组低了10．96％;每kg增重成本节约了0．89元。育肥猪试验一组日增重较高,比对照组增加了23g,提高幅度为3．09％,试验二组与对照组日增重相当;试验一组、试验二组料肉比分别比对照组降低了1．15％和3．2％;试验一组、试验二组每kg增重成本分别比对照组节约了0．44元和0．49元;试验组瘦肉率与对照组相比没有显著差异。从各指标的趋势上看,试验组的生长表现和经济效益均优于对照组．     

低蛋白日粮对生长猪及育肥猪的影响

选取初始体重为25kg的杜×大×长三元健康生长猪176头及初始体重为50kg的杜×大×长三元健康育肥猪144头。采用单因子设计,分为对照组和试验组;对照组中日粮按照NRC（1998）营养需要量推荐配制,试验组在NRC推荐的日粮粗蛋白质水平上降低4个百分点探讨低蛋白质日粮对生长猪和育肥猪生长性能的影响。结果表明：生长猪试验组日增重比对照组增加了46g,提高幅度为6．82％：料肉比比对照组低10．96％：增重成本节约0．89元／kg体重。育肥猪试验1组日增重较高．比对照组增加23g．提高幅度为3．09％。试验2组与对照组日增重相当;试验1组、试验2组料肉比分别比对照组降低1．15％和3．2％;试验1组、试验2组增重成本分别比对照组节约0．44元／kg体重和0．49元／kg体重;试验组瘦肉率与对照组相比没有显著差异。从各指标的趋势上看．试验组的生长表现和经济效益均优于对照组．     

低蛋白日粮对生长猪生长性能和腹泻率的影响

本研究旨在探讨低蛋白日粮对生长猪生长性能和腹泻率的影响。试验选取初始体重为16kg左右的三元（杜×长×大）健康生长猪66头,采用单因子试验设计,分为对照组和试验组,每组设3个重复,每个重复11头;对照组日粮按照NRC（1998）推荐营养需要量配制,试验组在NRC推荐日粮粗蛋白水平上降低3.8个百分点,试验期30d。结果表明,试验组日增重比对照组增加了23．4g,提高幅度为4．6％（P〈0．05）;料肉比降低了0．22,降低幅度为10．8％（P〈0．05）;试验组腹泻率与对照组相比,有下降趋势,但无显著性差异（P〉0．05）。说明使用低蛋白日粮能提高生长猪的生长性能和饲料转化率,并在一定程度上能减少仔猪腹泻。     

低蛋白日粮对生长猪生长性能和腹泻率的影响

本研究旨在探讨低蛋白日粮对生长猪生长性能和腹泻率的影响。试验选取初始体重为16kg左右的三元（杜×长×大）健康生长猪66头,采用单因子试验设计,分为对照组和试验组,每组设3个重复,每个重复11头：对照组日粮按照NRC（1998）推荐营养需要量配制,试验组在NRC推荐日粮粗蛋白水平上降低3．8个百分点,试验期30天。结果...     

低蛋白日粮对育肥猪生产性能和养分消化率的影响

试验研究了低蛋白日粮对育肥猪生产性能和养分消化率的影响,试验选择初始体重为70kg的杜×大×长三元猪80头,采用单因子设计,分为对照组和试验组。对照组中日粮按照NRC(1998)营养需要量推荐配制,试验组在NRC推荐的日粮粗蛋白水平上降低3.1个百分点。试验结果表明:试验组日增重比对照组增加了85g,提高幅度为10.88%(P0.01);试验组料肉比比对照组降低了12.11%(P0.01);试验组单位增重成本比对照组节约了1.09元/kg(P0.01)。试验结果还表明:试验组氨基酸消化率均高于对照组,其中赖氨酸、苏氨酸和色氨酸消化率显著高于对照组(P0.01);蛋氨酸消化率极显著高于对照组(P0.05);粗脂肪和粗蛋白的消化率极显著高于试验组(P0.01);而血清尿素氮含量极显著低于对照组(P0.01)。从各指标的趋势上看,试验组的生长性能、养分消化率和经济效益均优于对照组。     

低蛋白日粮对瘦肉型猪生长性能及胴体品质的调控

本试验日粮研究低蛋白日粮对点瘦肉型猪生长性能和肉品质的影响,结果表明：日粮赖氨酸含量≥0．9％时,降低蛋白2个百分点,不影响猪的生长性能、屠宰性能和肉品质;而当日粮赖氨酸含量〈0．9％时,日粮蛋白含量降低,则显著降低猪的生长性能和屠宰性能,对内品质无显著影响,但肉色评分有所降低。     

低蛋白日粮对瘦肉型猪生长性能及胴体品质的调控

本试验日粮研究低蛋白日粮对点瘦肉型猪生长性能和肉品质的影响,结果表明:日粮赖氨酸含量≥0.9%时,降低蛋白2个百分点,不影响猪的生长性能、屠宰性能和肉品质;而当日粮赖氨酸含量<0.9%时,日粮蛋白含量降低,则显著降低猪的生长性能和屠宰性能,对肉品质无显著影响,但肉色评分有所降低。     

低蛋白日粮下赖氨酸水平对生长猪氮平衡和生长性能的影响

试验选用12头初始体重为(15.33±2.10)kg健康杜×长×大杂交去势公猪,分为6个处理,采用6×6双拉丁方设计,研究低蛋白日粮条件下赖氨酸水平对生长猪氮平衡和生长性能的影响。试验日粮包括1个高蛋白对照组(粗蛋白水平为18%,标准可消化赖氨酸0.83%)和5个低蛋白处理组(粗蛋白水平为14%,标准可消化赖氨酸水平分别为0.63%、0.73%、0.83%、0.93%和1.03%)。结果表明:日粮粗蛋白水平降低4%后,生长猪的氮排放量显著降低(P<0.01),氮沉积率和生物学价值随着日粮赖氨酸水平的升高呈线性上升(P<0.01);日粮粗蛋白和赖氨酸水平对生长猪的生长性能并无显著影响(P>0.05)。综合考虑日粮标准可消化赖氨酸水平对生长猪氮平衡和生长性能这两方面的影响,当日粮粗蛋白水平较《猪饲养标准》(2004)的推荐标准降低4%时,15~40kg生长猪最适日粮标准回肠可消化赖氨酸水平为0.93%~1.03%。     

Effects of low-protein diets supplemented with crystalline amino acids on performance and intestinal development in piglets over the first 2 weeks after weaning

This study was conducted to determine the effects of low-protein diets supplemented with crystalline amino acids (AA) on performance and intestinal development in barrows (n = 32) over 2 weeks after weaning at 18 ± 1 day. Four maize-soybean meal based diets providing 0.93 g standardized ileal digestible lysine/MJ ME were prepared. The treatments were a control diet containing 23.1% CP (crude protein) and three low-protein diets (21.2, 18.9, and 17.2% CP, respectively), which were supplemented with crystalline AA to achieve an ideal AA pattern. Piglets were raised individually and had free access to feed and water. Average daily gain (ADG) and average daily feed intake (ADFI) were measured weekly. Severity of diarrhea was monitored twice per day. Blood from all piglets was taken for determining serum urea nitrogen on d 0, 7, and 14 and serum free AA concentration on d 14. At the end of the experiment, all piglets were killed to measure morphology of the small intestine and disaccharidase activities. Reducing CP level did not affect ADFI (P > 0.10) but resulted in poorer (linear, P < 0.05; quadratic, P < 0.05) ADG and feed:gain ratio (F:G) over the 2-week study period. However, most of the effect of dietary CP was due to the significant deterioration of performance with the 17.2% CP diet. Faecal consistency was improved linearly (P < 0.01) with dietary CP decrease. Reducing dietary CP from 23.1 to 17.2% resulted in a linear (P < 0.001) and quadratic (P < 0.001) decrease in serum urea nitrogen levels on d 7 and 14. Serum arginine (P < 0.001), glutamine (P < 0.05), and proline (P < 0.05) concentrations were decreased in pigs fed the 17.2% CP diet compared with those fed the control diet on d 14. Villous height was decreased (P < 0.05) in the duodenum and jejunum by the reduction of dietary CP. As dietary CP declined, lactase and sucrase activities were reduced (P < 0.01) in the proximal jejunum. In conclusion, reducing CP concentration from 23.1 to 17.2% led to decreased growth performance associated with morphological changes of the gut and reduced disaccharidase activities in the small intestine. But reducing dietary CP from 23.1 to 18.9% did not affect intestinal morphology and disaccharidase activities.     

Dietary chenodeoxycholic acid improves growth performance and intestinal health by altering serum metabolic profiles and gut bacteria in weaned piglets

Nutritional diarrhea and subsequent performance degradation in weaned piglets are major challenges for the pig industry. Bile acids (BA) can be added to the diet as emulsifiers. This experiment was conducted to investigate the effects of chenodeoxycholic acid (CDCA), a major primary BA, on growth performance, serum metabolic profiles and gut health in weaned piglets. A total of 72 healthy weaned piglets were randomly assigned to the control (CON) and the CDCA groups, which were feed a basal diet and the basal diet supplemented with 200 mg/kg CDCA for 30 d, respectively. Our results demonstrated that CDCA significantly increased final BW and average daily gain (ADG), decreased feed-to-gain (F:G) ratio and tended to reduce diarrhea incidence. In addition, CDCA increased the villus height-to-crypt depth (V:C) ratio, elevated goblet cell numbers and the expression of tight junction proteins, suggesting the enhancement of intestinal barrier function. As an emulsifier, CDCA increased jejunal lipase activity and the mRNA expression of pancreatic lipases. CDCA supplementation also altered the serum metabolic profiles, including increasing the levels of indole 3-acetic acid, N′-formylkynurenine and theobromine that were beneficial for gut health. Moreover, the relative abundance of 2 beneficial gut bacteria, Prevotella9 and PrevotellaceaeTCG-001, were increased, whereas the relative abundance of a harmful bacteria, Dorea, was decreased in the gut of weaned piglets supplemented with CDCA. Importantly, the altered serum metabolic profiles showed a strong correlation with the changed gut bacteria. In conclusion, CDCA improved the growth performance of weaned piglets by improving intestinal morphology and barrier function, and enhancing lipid digestion, accompanied by alterations of serum metabolic profiles, and changes in relative abundance of certain gut bacteria.     

Bacillus amyloliquefaciens CECT 5940 improves performance and gut function in broilers fed different levels of protein and/or under necrotic enteritis challenge

Two studies were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/−), and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/−). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/−). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels (P < 0.001). Supplementation of BA increased BWG (P < 0.001) and reduced FCR (P = 0.043) across dietary treatments, regardless of challenge. Bacillus (P = 0.030) and Ruminococcus (P = 0.029) genomic DNA copy numbers and concentration of butyrate (P = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG (P = 0.010) and uric acid levels in serum (P < 0.001). Supplementation of BA improved BWG (P = 0.001) and FCR (P = 0.005) and increased Ruminococcus numbers (P = 0.018) and butyrate concentration (P = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced Clostridium perfringens numbers only in birds fed with RCP diets (P = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine (P = 0.013), valine (P = 0.020), and lysine (P = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.     

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

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

低蛋白质日粮不同能量水平对育肥猪生长性能和胴体性状的影响

本研究旨在探讨低蛋白质日粮中不同能量水平对育肥猪生长性能、胴体性状的影响.选用70 kg的杜长大三元杂交猪216头,按试验要求随机分为6个处理,每个处理6个重复,每个重复6头猪,对照组日粮参照NRC(1998)推荐标准设计,蛋白质水平为15.5%,消化能水平为14.27 MJ/kg,试验Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组日粮蛋白质水平在对照组基础上下调4个百分点,并补充赖氨酸、蛋氨酸、苏氨酸和色氨酸满足氨基酸需要,消化能水平分别为14.48、14.26、13.88、13.52、13.26 MJ/kg.结果表明,与对照组相比,试验组的生长性能、胴体性状和血清氨基酸(精氨酸除外)及尿素氮没有显著影响(P>0.05);各试验组之间,随着能量水平的降低,日增重显著上升(P=0.02),肉料比表现出上升的趋势(P=0.06),采食量没有受到能量水平降低的影响(P=0.86),无脂瘦肉率显著提高(P=0.01),而脂肪率显著下降(P=0.03);试验Ⅳ、Ⅴ组日增重、肉料比显著高于试验Ⅱ组(P<0.05),对照组和试验Ⅴ组眼肌面积和无脂瘦肉率显著高于试验Ⅱ组(P<0.05),而脂肪率显著低于试验Ⅱ组(P<0.05),除试验Ⅰ组外,其余各试验组血清尿素氮含量均显著低于对照组(P<0.05).综合考虑能量水平对育肥猪生长性能和胴体性状两方面的影响,日粮蛋白质水平较NRC(1998)推荐的标准降低4个百分点,消化能水平降低到13.26 MJ/kg较为合适.     

Dietary ferulic acid and vanillic acid on inflammation,gut barrier function and growth performance in lipopolysaccharide-challenged piglets

Ferulic acid(FA) and vanillic acid(VA) are considered as major phenolic metabolites of cyanidin 3-glucoside, a polyphenol that widely exists in plants that possess a protective effect against oxidative stress and inflammation in our previous study. This study aimed to investigate the effect of FA and VA on inflammation, gut barrier function, and growth performance in a weaned piglet model challenged with lipopolysaccharide(LPS). Thirty-six piglets(PIC 337 × C48, 28 d of age) were randomly alloca...     

Dietary organic acid and fiber sources affect performance,intestinal morphology,immune responses and gut microflora in broilers

This experiment was designed to investigate the effects of a dietary organic acid (OA) mixture and 2 fiber sources on performance, intestinal morphology, immune responses and gut microflora in broilers. A total of 390 one-day-old broiler chicks (Ross 308) were allocated to 6 dietary treatments with 5 replicate pens and 13 chicks each based on a factorial arrangement (2 × 3) in a completely randomized design. The experiment lasted 42 d. The following experimental diets and as well as their interaction were considered: a basal diet supplemented with or without OA (0 or 1 g/kg) and 2 fiber sources (sugar beet pulp [soluble fiber] or rice hull [insoluble fiber]; 0 or 30 g/kg). Dietary supplementation of OA increased daily weight gains of broilers across the entire rearing period (P < 0.05). The dietary fibrous materials did not affect the performance of broilers. Antibody titer against influenza disease virus was higher in birds fed diets containing rice hull compared with other experimental groups (P < 0.05). The population of Lactobacillus bacteria was greater in birds fed OA-added diets without or with 30 g/kg rice hull supplementation compared with other experimental groups (P < 0.05). In conclusion, dietary supplemental OA improved performance of broilers, and dietary supplemental OA with rice hull enhanced humoral immune responses.     

不同杂交组合商品猪的肥育性能与胴体品质研究

本研究选用二元长大（L×Y）、三元杜长大（D×LY）、四元皮杜长大（PD×LY）三个杂交组合猪群为实验动物,进行生长发育性能、胴体品质性状测定,旨在为优质肉高效配套杂交组合筛选提供理论依据。研究表明：PD×LY日增重、料肉比及屠宰率最优,日增重、屠宰率与L×Y差异显著（P〈0．05）;PD×LY眼肌面积、后腿比例分别为48．09cm2、34．23％,为三组合中最高,并与L×Y差异显著（P〈0．05）,与D×LY组差异不显著（P〉0．05）。     

在不同有效磷日粮中添加植酸酶对仔猪生产性能的影响

将体重相近的60头15kg左右的杜长大仔猪分为5个处理（对照组、AP降低0．1％、AP降低0．12％、AP降低0．1％＋酶、AP降低0．12％＋酶），每个处理3个重复，每重复4头仔猪。研究结果表明：曰粮有效磷水平和植酸酶对仔猪生长、料重比都有显著的影响（P〈0．05），与对照组相比，当日粮有效磷水平降低0．1％，仔猪体重、日增重会显著降低，而料重比显著上升；当有效磷降低0．1％添加植酸酶时，仔猪体重、日增重会显著增加，而料重比显著下降；当日粮有效磷降低0．12％时，不论加酶与否，其体重、日增重都会显著下降，而料重比会显著增加。     

Fiber effects in nutrition and gut health in pigs

Dietary fiber is associated with impaired nutrient utilization and reduced net energy values. However, fiber has to be included in the diet to maintain normal physiological functions in the digestive tract. Moreover, the negative impact of dietary fiber will be determined by the fiber properties and may differ considerably between fiber sources. Various techniques can be applied to enhance nutritional value and utilization of available feed resources. In addition, the extent of fiber utilization is affected by the age of the pig and the pig breed. The use of potential prebiotic effects of dietary fiber is an attractive way to stimulate gut health and thereby minimize the use of anti-microbial growth promoters. Inclusion of soluble non-starch polysaccharides （NSP） in the diet can stimulate the growth of commensal gut microbes, inclusion of NSP from chicory results in changes in gut micro-environment and gut morphology of pigs, while growth performance remains unaffected and digestibility was only marginally reduced. The fermentation products and pH in digesta responded to diet type and were correlated with shifts in the microbiota. Interestingly, fiber intake will have an impact on the expression of intestinal epithelial heat-shock proteins in the pig. Heat-shock proteins have an important physiological role in the gut and carry out crucial housekeeping functions in order to maintain the mucosal barrier integrity. Thus, there are increasing evidence showing that fiber can have prebiotic effects in pigs due to interactions with the gut micro-environment and the gut associated immune system.