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Use of crystalline methionine to optimize amino acid profiles in feeds for Atlantic salmon (Salmo salar L.) was studied in three experiments. A basic experimental diet with 25% of dietary protein from marine origin and the remaining 75% from soya protein concentrate was used either with or without supplementation of L ‐methionine, D ‐methionine or DL ‐methionine. A fishmeal‐based diet was used as control. In experiment 1, growth performance of 100 g salmon in seawater was improved by supplementation with the different methionine products. Growth performance was, however, inferior to that of fish fed the control. Feed conversion ratios (FCR) exhibited similar trends to specific growth rate (SGR) with methionine supplementation, but again not as the control. Protein retention, measured as productive protein value (PPV), was significantly better in the control and D ‐methionine groups as compared with either L ‐methionine or the nonsupplemented group. These trends were confirmed in experiment 2, using fish of the same size, where an absorption and digestibility study of D ‐ and L ‐methionine clearly indicated that D ‐methionine was absorbed as well as L ‐methionine. Results indicated that racemization of D ‐ into L ‐methionine occurs in liver and kidney in Atlantic salmon. Ornithine decarboxylase (ODC) activity in liver was significantly affected by dietary treatment and there was a good correlation with growth and feed utilization data. In experiment 3, a growth study with large salmon (1 kg) was performed using increasing supplementation of DL ‐methionine to the basic diet. Results indicated a methionine requirement for maximum growth of 9.2 g kg–1 feed dry matter (DM) kg–1 growth. This is slightly higher than that reported in the literature. The present study clearly shows that optimizing the amino acid profile by inclusion of a single crystalline amino acid (crystalline methionine) does not give the same protein utilization as that of a diet in which the amino acids are mainly protein bound. D ‐methionine was found to result in better protein utilization than L ‐methionine when measured as PPV. 相似文献
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Charmaine D Espinosa John K Mathai Laia Blavi Yanhong Liu John K Htoo J Caroline Gonzalez-Vega Hans H Stein 《Journal of animal science》2021,99(9)
An N-balance experiment was conducted to test the hypothesis that d-Methionine (d-Met) has the same bioavailability and efficacy as l-Methionine (l-Met) when fed to weanling pigs. A Met-deficient basal diet containing 0.24% standardized ileal digestible (SID) Met was formulated. Six additional diets were formulated by adding 0.036%, 0.072%, or 0.108% d-Met or l-Met to the basal diet, and these diets, therefore, contained 77%, 87%, or 97% of the requirement for SID Met. Fifty-six barrows (10.53 ± 1.17 kg) were housed in metabolism crates and allotted to the seven diets with eight replicate pigs per diet. Feces and urine were collected quantitatively with 7-d adaptation and 5-d collection periods. Blood and tissue samples from pigs fed the basal diet and pigs fed diets containing 0.108% supplemental Met were collected on the last day. Results indicated that N retention (%) linearly increased (P < 0.01) as supplemental d-Met or l-Met increased in diets. Based on N retention (%) as a response, the linear slope-ratio regression estimated the bioavailability of d-Met relative to l-Met to be 101% (95% confidence interval: 57%–146%). The villus height and crypt depth in the jejunum were not affected by the Met level or Met source. Total antioxidant capacity or thiobarbituric acid reactive substance concentrations in plasma or tissue samples from pigs fed the control diet or diets containing 0.108% supplemental d-Met or l-Met were not different. Abundance of mRNA for some AA transporters analyzed in intestinal mucosa of pigs also did not differ. Therefore, it is concluded that d-Met and l-Met are equally bioavailable for weanling pigs. 相似文献
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Hua Zhou Zhengcai Yuan Daiwen Chen Huifeng Wang Yan Shu Jun Gao John Khun Htoo Bing Yu 《Journal of animal science》2021,99(6)
Two nitrogen balance studies were conducted to evaluate the relative bioavailability values (RBV) of dl-methionine (dl-Met) and dl-methionine hydroxy analog calcium salt (MHA-Ca) to l-methionine (l-Met) as Met sources fed to pigs. In experiment 1, 42 pigs were assigned to 7 treatments feeding with basal diet (BD) formulated to be deficient in Met (0.22% standardized ileal digestible basis) but adequate in other amino acids. Diets included (1) BD, (2) BD + 0.025% dl-Met, (3) BD + 0.050% dl-Met, (4) BD + 0.075% dl-Met, (5) BD + 0.025% l-Met, (6) BD + 0.050% l-Met, and (7) BD + 0.075% l-Met. Increasing levels of l-Met and dl-Met enhanced N retained (g/d) and N retention (% of intake) linearly (P < 0.01). Using a linear slope ratio procedure, a product-to-product RBV of dl-Met compared with l-Met was 94% (95% confidence limits: 65% to 123%) based on N retained expressed as g/d and 99% (95% confidence limits: 70% to 128%) for N retention expressed as % of intake. In experiment 2, 42 pigs were allotted to 7 treatments in another N-balance trial. Diets included (1) BD, (2) BD + 0.025% l-Met, (3) BD + 0.050% l-Met, (4) BD + 0.075% l-Met, (5) BD + 0.030% MHA-Ca, (6) BD + 0.060% MHA-Ca, and (7) BD + 0.089% MHA-Ca. An increase in dietary inclusion rates of l-Met increased (P < 0.01) N retained (g/d) linearly while increasing levels of MHA-Ca had no effects (P > 0.05) on N retained (g/d) and N retention (% of intake). Using linear slope-ratio regression, the RBV of MHA-Ca compared with l-Met was 70% (95% confidence limits: 59% to 81%) on a product-to-product basis or 83% on equimolar basis based on N retained expressed as g/d. Overall, the mean RBV of dl-Met to l-Met of 97% (95% confidence limits cover 100%) indicated that dl-Met and l-Met are equally bioavailable as Met sources in pigs. Compared with l-Met, the RBV of MHA-Ca was lower at 70% (95% confidence limits: 59% to 81%) on a product-to-product basis or 83% on equimolar basis in starter pigs. 相似文献
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采用不同浓度的L-蛋氨酸培养液培养秧苗,并用L-亮氨酸15N喷施分蘖期、抽穗期和蜡熟期水稻叶面,研究水稻根系对L-蛋氨酸、水稻叶面对L-亮氨酸15N吸收情况。结果表明,用1 000、2 000、3 000、4 000 mg/L的L-蛋氨酸溶液浸根培养,与对照相比,秧苗L-蛋氨酸含量分别增加8.2%,9.8%、19.7%、21.3%;用500 mg/L的L-亮氨酸15N在分蘖期、抽穗期和蜡熟期喷施水稻叶面,三个时期都会不同程度吸收L-亮氨酸,吸收最好的时期是抽穗期和蜡熟期。 相似文献
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鲤肠道对L-甲硫氨酸和L-苯丙氨酸的离体吸收动力学 总被引：1，自引：0，他引：1
采用离体灌注试验系统和茚三酮对氨基酸显色的试验方法,定量分析了鲤鱼肠道壁对氨基酸吸收和跨壁运输量,在相同的实验环境下,分别研究鲤鱼肠道对对L-甲硫氨酸和L-苯丙氨酸的吸收转运量。结果表明,在60 min内草鲤鱼道可对灌流液的氨基酸进行持续的吸收转运,并在肠道外积累;当肠道内灌流氨基酸浓度逐渐增加时,肠道外培养液中氨基酸的浓度与其起始浓度呈正相关变化,并未出高浓度氨基酸对吸收转运的“抑制”效应;通过对吸收转运量达到最大值时试验氨基酸的浓度与吸收转运量的比较,以及在氨基酸吸收转运量随时间的变化规律等的比较分析表明,鱼肠道对L-甲硫氨酸和L-苯丙氨酸的吸收。结果表明,鲤鱼肠道能有效地吸收、运输L-甲硫氨酸和L-苯丙氨酸。鲤鱼肠道对L-甲硫氨酸和L-苯丙氨酸的吸收曲线符合Michaelis-Menten方程。两种氨基酸的吸收动力学方程分别为：1/V =0.1251×1/[S] + 0.0524（R2=0.9781,P<0.05）和1/V=0.1887×1/[S]+0.0288（R2=0.9762,P<0.05）,动力学参数为：L-甲硫氨酸：Vmax=19.08µmol/g•min,Kmax=2.39mmol/L;L-苯丙氨酸：Vmax=34.72µmol/g•min,Kmax=6.55mmol/L。吸收动力学特征分析表明：鲤鱼肠道对两种氨基酸的吸收是一种逆浓度、需要转运载体的主动吸收方式,且对不同的氨基酸有不同的吸收、运输特异性,鲤鱼肠道对L-甲硫氨酸的吸收率和跨壁运输能力均强于L-苯丙氨酸（P<0.05)。 相似文献
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【目的】研究L-蛋氨酸强化卤虫无节幼体对鳙开口苗生长、氨基酸组成及肌酸激酶、γ-谷氨酰转移酶、Na~+K~+-ATP酶活性的影响,为鳙开口苗的培育提供参考。【方法】用0(对照),400,800,1 600mg/L的L-蛋氨酸强化初孵卤虫无节幼体(Artemia nauplii)16h,投喂鳙(Aristichthys nobilis)开口苗21d,分别于试验第7,14和21天取样测定鳙开口苗的体长和体质量,第21天取样测定开口苗体内氨基酸组成和相关酶活性。【结果】试验第7和14天,L-蛋氨酸对各处理组鳙开口苗的特定增长率(SGR)和体长日增长率(BLGR)无显著影响(P0.05);在试验第21天,400和800mg/L L-蛋氨酸处理组鳙开口苗的SGR、BLGR显著高于0和1 600 mg/L L-蛋氨酸组(P0.05)。L-蛋氨酸能显著提高各处理组卤虫无节幼体和鳙开口苗体内的蛋氨酸含量,且各处理组之间蛋氨酸含量差异显著(P0.05);800mg/L L-蛋氨酸处理组鳙开口苗总氨基酸含量显著高于0和1 600mg/L组(P0.05);400和800mg/L L-蛋氨酸组鳙开口苗赖氨酸(Lys)、精氨酸(Arg)和半胱氨酸(Cys)的含量显著高于0和1 600mg/L L-蛋氨酸组;800mg/L L-蛋氨酸组鳙开口苗甘氨酸(Gly)和丙氨酸(Ala)的含量显著高于0和400 mg/L L-蛋氨酸组(P0.05);800mg/L L-蛋氨酸组鳙开口苗苏氨酸(Thr)含量显著高于其他3组(P0.05);800mg/L L-蛋氨酸组鳙开口苗的苯丙氨酸(Phe)含量显著高于对照组(P0.05)。800mg/L L-蛋氨酸组鳙开口苗肌酸激酶、γ-谷氨酰转移酶活性显著高于其他3组(P0.05);400和800mg/L L-蛋氨酸组鳙开口苗的Na+K+-ATP酶活性显著高于0和1 600mg/L L-蛋氨酸组(P0.05)。【结论】在本试验条件下,800mg/L L-蛋氨酸强化的卤虫无节幼虫能有效改善鳙开口苗体内的氨基酸组成和相关酶活性,进而提高其生长性能。 相似文献
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