Practical starter pig amino acid requirements in relation to immunity,gut health and growth performance

Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytokines that orchestrate the immune response. The classic responses observed with immune system activation and cytokine production include： anorexia, fever, lethargy, recruitment of other immune cells, and phagocytosis. While production of immune system components is known to require some amino acids, increases in amino acid requirements are more than offset by the associated decrease in protein accretion and increased muscle protein degradation that also accompanies immune system activation. However, the biggest impact of cytokine production is a decrease in feed intake. Therefore, as feed intake decreases, the energy needed to drive protein synthesis is also decreased. This suggests that diets should still be formulated on a similar calorie：lysine ratio as those formulated for non-immune challenged pigs. The evidence is sparse or equivocal for increasing nutrient requirements during an immune challenge. Nutritionists and swine producers should resist the pressure to alter the diet, limit feed, or add expensive feed additives during an immune challenge. While immune stimulation does not necessitate changes in diet formulation, when pigs are challenged with non-pathogenic diarrhea there are potential advantages on gut health with the increased use of crystalline amino acids rather than intact protein sources （i.e., soybean meal）. This is because reducing crude protein decreases the quantity of fermentable protein entering the large intestine, which lowers post weaning diarrhea. It also lowers the requirement for expensive specialty protein sources or other protein sources such as soybean meal that present immunological challenges to the gut. The objective of this review is two-fold. The first is to discuss immunity by nutrition interactions, or lack thereof, and secondly, to review amino acid re     

Practical starter pig amino acid requirements in relation to immunity,gut health and growth performance

Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytokines that orchestrate the immune response. The classic responses observed with immune system activation and cytokine production include: anorexia, fever, lethargy, recruitment of other immune cells, and phagocytosis. While production of immune system components is known to require some amino acids, increases in amino acid requirements are more than offset by the associated decrease in protein accretion and increased muscle protein degradation that also accompanies immune system activation. However, the biggest impact of cytokine production is a decrease in feed intake. Therefore, as feed intake decreases, the energy needed to drive protein synthesis is also decreased. This suggests that diets should still be formulated on a similar calorie:lysine ratio as those formulated for non-immune challenged pigs. The evidence is sparse or equivocal for increasing nutrient requirements during an immune challenge. Nutritionists and swine producers should resist the pressure to alter the diet, limit feed, or add expensive feed additives during an immune challenge. While immune stimulation does not necessitate changes in diet formulation, when pigs are challenged with non-pathogenic diarrhea there are potential advantages on gut health with the increased use of crystalline amino acids rather than intact protein sources (i.e., soybean meal). This is because reducing crude protein decreases the quantity of fermentable protein entering the large intestine, which lowers post weaning diarrhea. It also lowers the requirement for expensive specialty protein sources or other protein sources such as soybean meal that present immunological challenges to the gut. The objective of this review is two-fold. The first is to discuss immunity by nutrition interactions, or lack thereof, and secondly, to review amino acid requirement estimates for nursery pigs.     

The effects of dietary concentrations of minerals, source of protein, amino acids and antibiotics on the growth of and digestibility of amino acids by broiler chickens

1. The effects of dietary calcium, available phosphorus, amino acid and antibiotic supplements on the digestibilities of amino acids and growth of broiler chickens were investigated in two experiments. 2. The performance of chickens fed on diets containing high concentrations of calcium and available phosphorus was poorer with meat meal-based diets than with soyabean-based diets. Methionine supplementation improved the performance of chickens fed meat meal-based diets. 3. A high dietary content of calcium (25.9 vs 11.8 g/kg) reduced chick performance and the digestibility of glutamic acid, leucine and phenylalanine but increased the digestibility of lysine and histidine. 4. High dietary contents of calcium and available phosphorus (24.3 and 13.0 vs 11.8 and 4.0 g/kg) reduced chick performance and the digestibilities of most amino acids. 5. Antibiotic supplementation did not improve the performance of chickens, but increased the digestibilities of most amino acids in chickens fed on diets with a high calcium or high calcium and available phosphorus contents. 6. It was concluded that excess dietary calcium alone, or calcium and phosphorus together, reduced chick performance and the digestibilities of most amino acids. Growing chickens tolerated excess dietary calcium and available phosphorus better in well-balanced amino acid diets, such as soyabean meal or methionine-supplemented meat meal diets, than in poorly balanced amino acid diets, such as unsupplemented meat meal diets.     

Muscle growth and plasma concentrations of amino acids, insulin-like growth factor-I, and insulin in growing pigs fed reduced-protein diets

Twenty barrows were used to determine if partial replacement of protein-bound AA with crystalline AA (CAA) reduces AA use for muscle tissue and whole-body growth. Barrows (44.2 +/- 1.3 kg of BW) were assigned to 4 diets in a randomized complete block design. Diets consisted of 16.1% CP with no CAA, and 12.8, 10.1, and 7.8% CP containing CAA. As the CP concentration decreased, CAA were gradually increased to meet requirements on a true ileal digestibility basis. Barrows were weighed on d 0 and 13. Blood samples were collected before the morning feeding on d 0, 6, and 12 (prefeeding), and 2 h after the morning feeding on d 13 (postfeeding). Pigs were euthanized on d 13, and liver and right LM were removed and weighed. The reduction in the dietary CP concentration linearly decreased (P < 0.01) ADG, G:F, LM weight, and the CP content of LM. Reducing the CP concentration decreased pre- and postfeeding plasma concentrations of IGF-I (linear, P < 0.01) and insulin (linear, P < 0.10). The reduction in the dietary CP concentration increased prefeeding plasma concentrations of Ala, Gln, Gly, and total AA but decreased Arg, Asn, His, Ile, Phe, Trp, and Tyr (linear, P < 0.05). Plasma concentration of total indispensable AA decreased initially and increased thereafter as the dietary CP concentration decreased from 16.1 to 7.8% (quadratic, P < 0.01). The reduction in the dietary CP concentration increased postfeeding plasma concentrations of Ala, Lys, Met (linear, P < 0.01), and Gly (linear, P = 0.073) and decreased Asn, Ser, Tyr, Arg, His, and Leu (linear, P < 0.05). Plasma concentrations of Ile, Phe, Thr, Trp, and Val decreased initially and increased thereafter as the dietary CP concentration decreased from 16.1 to 7.8% (quadratic, P < 0.05). In muscle tissue, concentrations of free Ala, Asp, Glu, Gln, Gly, and Lys increased (linear, P < 0.05) as the dietary CP concentration decreased. Concentrations of free His, Ile, Phe, Thr, Trp, and Val in muscle tissue decreased initially and increased thereafter as the dietary CP concentration decreased from 16.1 to 7.8% (quadratic, P < 0.05). In summary, the reduction in the dietary protein-bound AA decreased whole-body and LM growth, altered the free AA pool profile in muscle tissue, and decreased plasma insulin and IGF-I. As the replacement of protein-bound AA with CAA increased, 1) free Ala and Gln in muscle tissue increased, indicating an increase of muscle tissue protein breakdown; and 2) utilization of indispensable AA in muscle tissue decreased.     

饲粮含硫氨基酸水平对断奶仔猪生长性能、肠道形态及酶活性的影响

文章旨在研究饲粮含硫氨基酸水平对断奶仔猪生长性能、肠道形态及酶活性的影响。试验选择体重接近的28日龄断奶仔猪80头,称重后随机分为试验1、2、3、4组,各组饲粮中含硫氨基酸含量分别0.49%、0.64%、0.79%、0.94%,共进行21d。试验结果,仔猪平均日采食量(ADFI)随着饲粮中含硫氨基酸水平增加出现先增加后下降的趋势,料肉比(F/C)与之趋势相反,当含硫氨基酸含量为0.79%时(试验3组)生长性能最好。其中,试验2、3组仔猪平均日增重(ADG)较试验1组分别增加12.5%、15.9%(P<0.05),F/C较试验1组分别降低10.8%、12.4%(P<0.05)。饲粮中含硫氨基酸水平显著影响仔猪空肠形态,而对十二指肠、回肠形态无显著影响(P>0.05)。相比于试验1组,试验2、3、4组空肠绒毛高度(VH)分别增加8.6%、11.7%、9.1%(P<0.05),空肠隐窝深度(CD)分别下降22.6%、16.4%、12.7%(P<0.05),试验2、3组绒毛高度和隐窝深度比(V/C)较试验1组分别增加24.3%、17.4%(P<0.05)。除此之外,饲粮中含硫氨基酸显著影响仔猪空肠中碱性磷酸酶(ALP)活性(二次P<0.05)及麦芽糖酶活性(P<0.05)。综上所述,饲粮中含硫氨基酸水平显著影响断奶仔猪小肠发育及空肠内酶活性,改善生长。     

Dietary levels of protein and free amino acids affect pancreatic proteases activities,amino acids transporters expression and serum amino acid concentrations in starter pigs

The dietary contents of crude protein and free amino acids (AA) may affect the protein digestion and AA absorption in pigs. Trypsin and chymotrypsin activities, AA serum concentrations and expression of AA transporters in the small intestine of pigs fed a low protein, AA‐supplemented (19.2%, LPAA) or a high protein (28.1%, HP), wheat‐soybean meal diet were measured in two 14‐d trials. The LPAA diet contained free L‐Lys, L‐Thr, DL‐Met, L‐Leu, L‐Ile, L‐Val, L‐His, L‐Trp and L‐Phe. All pigs were fed the same amount of feed (890 and 800 g/d for trial 1 and 2 respectively). In trial 1, samples of mucosa (duodenum, jejunum and ileum) and digesta (duodenum and jejunum) were collected from 14 pigs (17.2 ± 0.4 kg); in trial 2, blood samples were collected from 12 pigs (12.7 ± 0.3 kg). The trypsin and chymotrypsin activities in both intestinal segments were higher in pigs fed the HP diet (p < 0.01). Trypsin activity was higher in jejunum than in duodenum regardless the dietary treatment (p < 0.05). Pigs fed the LPAA diet expressed more b^0,+AT in duodenum, B⁰AT1 in ileum (p < 0.05), and tended to express more y⁺LAT1 in duodenum (p = 0.10). In pigs fed the LPAA diet, the expression of b^0,+AT was higher in duodenum than in jejunum and ileum (p < 0.01), but no difference was observed in pigs fed the HP diet. Ileum had the lowest b^0,+AT expression regardless the diet. The serum concentrations of Lys, Thr and Met were higher in LPAA pigs while serum Arg was higher in HP pigs (p < 0.05). Serum concentrations of AA appear to reflect the AA absorption. In conclusion, these data indicate that the dietary protein contents affect the extent of protein digestion and that supplemental free AA may influence the intestinal site of AA release and absorption, which may impact their availability for growth of young pigs.     

Effect of glycine supplementation in low protein diets with amino acids from soy protein isolate or free amino acids on broiler growth and nitrogen utilisation

1. Here, it was investigated whether substitution of amino acids (AA) from soy protein isolate with free AA in low crude protein diets influences the growth performance and N utilisation in broilers, and whether interactions with dietary glycine equivalent (Gly_equi) concentration exist.

2. Birds were distributed in two 2 × 2 factorial arrangements of 48 floor pens containing 10 birds each, plus 48 metabolism cages containing two birds each. Experimental feed was provided for ad libitum consumption from d 7 to 22. Diets contained either a soy protein isolate at 79 g/kg or a mix of free AA, which supplied the same amount of 18 proteinogenic AA. A mix of free glycine and l-serine was used to obtain low and high (12.0 and 20.5 g/kg dry matter) levels of dietary Gly_equi.

3. Substitution of soy protein isolate with free AA reduced the average daily gain and feed efficiency, mainly due to reduced feed intake. Efficiency of N accretion was not influenced by the AA source or Gly_equi concentration on d 21, possibly due to the lower AA digestibility of soy protein isolate and higher urinary excretion of nitrogenous substances in the treatments with the AA mix.

4. The average daily weight gain of the treatments with high Gly_equi concentration was higher for both AA sources. This increase was due to higher average daily feed intake by broilers in the treatments with soy protein isolate and due to the increased feed efficiency in the treatments with the AA mix. Broilers exhibited different growth responses to dietary Gly_equi between the AA sources; however, these responses could not be attributed to the different utilisation of Gly_equi for uric acid synthesis.

     

氨基酸微量元素螯合物对异育银鲫生长及其品质的影响

试验研究了氨基酸微量元素螯合物对异育银鲫生长及其品质的影响。结果表明,①氨基酸微量元素螯合物替代无机微量元素能显著促进异育银鲫生长,提高饲料利用效率,其中,以65%替代无机微量元素的促生长效果最好,饲料利用效率最高,日特定生长率和饲料利用效率分别增加25.37%和26.32%。②用氨基酸微量元素螯合物替代无机微量元素后,鱼体水分、灰分含量无显著差异,以65%替代无机微量元素后,鱼体蛋白含量提高1.75%;鱼体脂肪含量在35%、50%、65%替代无机微量元素后,均有增加。③氨基酸微量元素螯合物35%、50%、65%替代无机微量元素,对鱼体肥满度没有产生影响,但内脏比均增加。④氨基酸微量元素螯合物以35%、50%、65%替代无机微量元素后,提高了成活率、降低了养殖饲料成本。⑤在氨基酸微量元素螯合物基础上再添加黄霉素,具有更好的促生长效果和更高的饲料利用效率。     

Effects of epidermal growth factor on placental amino acids uptake in pregnant rats

To evaluate the effects of epidermal growth factor (EGF) on placental amino acids uptake, transport activities for L-proline, L-leucine, and L-alanine were kinetically examined in placental microvillous vesicles(PMV) obtained from pregnant rats administered with EGF(100 and 200 microg/kg/day) from day 18 to 21 of pregnancy. The Vmax of Na(+)-dependent proline uptake remarkably increased with a dose-dependent manner of EGF, while Km did not change. In contrast, Vmax and Km values of Na(+)-dependent and -independent alanine, and Na(+)-independent leucine uptake were not affected. These results suggested that EGF enhanced proline transport activity in placental microvillous membranes, resulting in an increase of proline concentration in the fetal blood. The selective up-regulation of proline uptake was considered to contribute to fetal growth by EGF.     

氨基酸与免疫系统的相互作用

疾病和免疫机能抑制会影响动物的生长速度和饲料转化率，消除这种不利影响通常可以改善动物的生产性能。国内外新近的科学研究表明，氨基酸营养对提高动物的免疫机能具有积极作用，特定的氨基酸可以抵抗或消除疾病和免疫机能抑制的产生。但总的说来，在猪和禽的研究方面，关于氨基酸营养和免疫系统的相互作用的资料较少（ Williams等， 1997a； Stahly， 1996）。 1氨基酸对免疫系统的影响 　　氨基酸对免疫系统功能有一定的影响，它们或者通过影响免疫球蛋白的形成或者通过影响免疫球蛋白的活性而使机体免疫力下降，以下是影响免疫系统功…     

氨基酸分析仪测定饲料及其原料中的含硫氨基酸

本文采用过甲酸氧化水解法处理饲料及饲料原料样品、通过日立L-8900氨基酸自动分析仪检测样品中的含硫氨基酸含量,结果显示：每份试样平行测试结果相对偏差小于4％．蛋氨酸和胱氨酸峰面积回收率在93．02％～102．06％．该方法测定含硫氨基酸的重复性和准确性良好．氧化水解法比常规盐酸水解法处理样品检测含硫氨基酸．检测结果更为准确。     

Effects of rumen-protected amino acids on ruminant nitrogen balance, plasma amino acid concentrations and performance

A series of trials was conducted to determine the effects of supplemental rumen-protected methionine (RPMet) and lysine (RPLys) on nutrient metabolism and performance. In situ RPMet N disappearance was less than 4% following 48 h of incubation and was not affected (P greater than .05) by diet or resultant ruminal pH differences, indicating that RPMet was well protected from ruminal microbial degradation. Thirty-five Dorset-sired crossbred wether lambs (avg wt 28 kg) fed ground corn-soybean hull diets supplemented with urea were randomly assigned to one of the following treatments: 1) 0% RPMet, 2) .03% RPMet, 3) .06% RPMet, 4) .09% RPMet or 5) .12% RPMet. Dry matter, fiber and N digestibilities and N retention were not affected (P greater than .05) by treatment. Plasma methionine concentration tended to increase linearly (P less than .07) with dietary RPMet level. Six Simmental X Angus steers (avg wt 427 kg) were fed a corn grain-corn silage diet supplemented with urea and five levels of RPMet: 1) 0%, 2) .04%, 3) .08%, 4) .12% and 5) .16%. The plasma methionine concentration increased linearly (P less than .01) with dietary RPMet level. In a steer performance trial, no improvements in feedlot performance resulted due to these RPMet levels (P greater than .05), suggesting that the control diet (0% RPMet) was meeting the methionine requirement of these steers. The effects of RPMet and RPLys on growing and finishing steer feedlot performance also were evaluated. Treatments were 1) urea control, 2) soybean meal positive control, 3) .09% RPMet + .06% RPLys, 4) .12% RPMet + .08% RPLys and 5) .15% RPMet + .10% RPLys. In the growing trial, added RPMet and RPLys did not improve steer feedlot performance. In the finishing trial, only steers fed .09% RPMet + .06% RPLys had higher (P less than .05) gains than those fed the urea control diet. These trials indicate that postruminal methionine and lysine supplies were not limiting feedlot steer performance.     

陈化大米替代玉米对断奶猪生长性能、血液生化及游离氨基酸水平的影响

本研究旨在研究用陈化大米完全替代玉米对仔猪断奶后1～28?d生长性能、血液生化及游离氨基酸水平的影响.试验将21?d断奶、平均初始体重为(6.32±0.09)kg的480头仔猪随机分为2组,每组8个重复,每个重复30头.两组断奶仔猪在28?d的试验期中分别饲喂玉米和陈化大米为主的日粮.结果:与玉米组相比,陈化大米组仔猪...     

Dietary supplementation of sulfur amino acids improves intestinal immunity to Eimeria in broilers treated with anti-interleukin-10 antibody

Oral antibody to interleukin-10(anti-IL-10) enhances the intestinal immune defense against Eimeria. The sulfur amino acids methionine and cysteine(M+C) play essential roles in inducing and maintaining protective immune responses during intestinal infections. Hence, increased dietary M+C may support the anti-IL-10-induced intestinal immunity to Eimeria. Broilers(n = 640) were arranged in a 2 × 2 × 2factorial design with 2 levels of each of the 3 main factors: dietary standardized ileal digestible...     

包被精油复合酸化剂对断奶仔猪生长性能、肠道免疫及盲肠微生物的影响

研究旨在观察包被精油复合酸(microencapsulated complex of essential oils and organicacids, MEA)对断奶仔猪生长性能、免疫相关指标和盲肠微生物的影响及其机理探讨。选用断奶仔猪250头,随机分为5组,每组设5个重复,每个重复10头猪,分别饲喂基础日粮(BASE组)、基础日粮+0.05%MEA2(LA组)、基础日粮+0.08%MEA2(MA组)、基础日粮+0.20%MEA1(HA组)、基础日粮+0.20%MEA1+0.05%MEA2(BHA组),饲养试验时间为21 d。结果表明,LA、MA组断奶仔猪肝脏指数显著低于BASE组(P<0.05),但在日粮中添加MEA对断奶仔猪生长性能、血清IL-2、回肠OccludinmRNA相对表达量与空肠SlgA无显著影响(P>0.05);BASE、LA组、MA组回肠pH值均显著高于BHA组(P<0.05),且随着MEA添加量的增加,回肠pH值随之降低(P<0.01);MA组较LA组或HA组相比有增加血清IgG的趋势(0.050.05)。结果提示,在日粮中添加MEA可以降低断奶仔猪回肠pH值;在日粮中添加MEA2可以显著降低断奶仔猪肝脏指数;在日粮中添加0.08%的MEA2可以增强断奶仔猪免疫强度并可改善断奶仔猪盲肠微生物菌群结构。