日粮蛋白质和赖氨酸水平对AA肉鸡生长性能及肌肉品质的影响

研究日粮不同蛋白质和赖氨酸水平对肉仔鸡生长性能和肌肉品质的影响。结果表明:1)日粮蛋白质水平增加4%,平均体重显著上升6.84%、饲料转化率显著上升7.2%(P<0.05);日粮赖氨酸水平增加0.2%,体重呈二次曲线变化,饲料转化率显著提高4.9%(P<0.05)。2)随日粮蛋白质水平增加,胸肌和腿肌剪切力值上升,即嫩度极显著下降55%(P<0.01);低蛋白质水平下随赖氨酸水平增加0.2%,宰后45 min的胸、腿肌pH显著下降4.1%、3.8%(P<0.05)。这表明生长速度与肌肉品质呈负相关。     

外源高赖氨酸蛋白质基因对转基因玉米种子中蛋白质和氨基酸组分的影响

分析了将高赖氨酸蛋白质基因导入玉米后,转基因玉米种子中水溶蛋白、盐溶蛋白、醇溶蛋白和碱溶蛋白组分的变化。结果表明,醇溶蛋白和盐溶蛋白总量发生了增加,水溶蛋白总量保持稳定,而碱溶蛋白量有所下降。免疫印迹结果表明,外源高赖氨酸蛋白的表达量与转基因种子中赖氨酸含量呈正相关性。推测外源高赖氨酸蛋白的表达及富含赖氨酸的水溶蛋白和盐溶蛋白组成的改变是转基因玉米种子中赖氨酸提高的主要原因;转基因玉米种子蛋白质可能是外源基因通过非直接的方式导致的结果。     

Influence of Dietary Metformin on the Growth Performance and Plasma Concentrations of Amino Acids and Advanced Glycation End Products in Two Types of Chickens

Glycation is a non-enzymatic reaction inducing the bonding of glucose to amino acids and proteins. Glycated amino acids are not useful for protein synthesis, suggesting that glycation reduces the utilization of amino acids. Metformin (MF) is well known as a therapeutic drug for type II diabetes that inhibits glycation. It is possible that treatment with MF raises the utilization of amino acids by the inhibition of glycation, thereby improving the growth performance of chickens. In the present study, therefore, we investigated the influence of dietary MF on the growth performance, and plasma concentrations of free amino acids and N^ε-(Carboxymethyl)lysine (CML), which is an advanced glycation end product, in layer (Experiment 1) and broiler (Experiment 2) chickens. From 7 d of age, chicks were allowed free access to one of the experimental diets containing MF at 3 supplementation levels (0, 150, and 300 mg/kg diet) for 14 days. Body weight and feed intake were measured every week. At the end of the experiments, blood and breast muscle (M. pectoralis major) were collected for further analysis. Dietary MF did not affect weight gain, feed intake, or feed efficiency in both layer and broiler chickens. Dietary MF at the level of 150 mg/kg diet increased breast muscle weight in both layer and broiler chickens. Dietary MF increased plasma concentrations of branched chain amino acids and decreased concentrations of CML in layer chickens, although it did not affect plasma concentrations of glucose. The present study suggested that dietary MF might have the potency to increase breast muscle weight of layer chickens with an increment in plasma concentrations of branched-chain amino acids.     

Atypical ocular Chelonoid herpesvirus manifestations in a captive Loggerhead turtle (Caretta caretta)

A captive loggerhead turtle (Caretta caretta) of unknown sex, 3 years of age, presented with bilateral mucoid secretions, severe chemosis, conjunctival hyperemia, and globe retraction. The animal was evaluated ophthalmologically and systemically, and hematological, microbiological, and conjunctival cytological and biopsy samples were collected for complementary diagnosis. The histopathological examination showed amphophilic intranuclear inclusions associated with severe inflammatory infiltrate. The diagnosis of Chelonid alphaherpesvirus 5 (ChAHV 5) was confirmed with end point PCR. Following systemic treatment with L‐lysine, acyclovir and vitamin A, the ocular signs resolved. No amphophilic intranuclear inclusions were seen in a follow‐up biopsy 5 months later, and there has been no recurrence of clinical ophthalmic signs during a 4‐year follow‐up. It is suggested that ChAHV 5 be considered as a differential diagnosis in captive marine turtles that present for conjunctival disease other than fibropapillomatosis.     

Amino Acid Resources of the Wild Relative of Barley (Hordeum spontaneum) in Israel

Measurements were made on amino acid contents in collection of wild barley (Hordeum spontaneum)., grown in pot conditions, and in some Israeli breeding lines and cultivars of Hordeum vulgare. H. spontaneum was low in lysine content and high in prolilne plus glutamic acid compared to H. vulgare. Lysine content was positively correlated, in H. spontaneum, to all other ammo acids except proline and giutamic acid. Inter-populanon rnean differences for Iv-saie in H. spontaneum were small and lysine variation was obscured due to variation in protein content. The use of H. spomancum in breeding high protein. nutritionally improved barley is discussed.     

低蛋白日粮对蛋鸡产蛋性能和排泄量的影响

新罗曼蛋鸡在产蛋高峰期（产蛋率90％以上），饲喂低蛋白日粮（含粗蛋白小于14．5％），添加0．05％的赖氨酸和0．1％蛋氨酸其产蛋性能与饲喂产蛋高峰期全价饲料（含粗蛋白17．5％）比较，差异不显著。其干物质和氮的排泄量分别减少21．15％和15．81％。     

Dietary requirements of rainbow trout for tryptophan,lysine and arginine determined by growth and biochemical measurements

Three separate studies were performed to determine the dietary requirements of rainbow troutSalmo gairdneri for tryptophan (Trp), lysine (Lys) and arginine (Arg) from both growth and biochemical data. The growth studies were carried out over a 12 week period. From graphical plots of % mean weight gain against % amino acid in diet the following requirement values were obtained, Trp 0.25% diet (0.4% dietary crude protein); Lys 1.9% diet (4.3% dietary protein); and Arg 1.6–1.8% diet (3.6–4% dietary protein). Plasma and liver amino acid concentrations measured 20h after feeding did not prove useful for determination of requirement values. Hepatic activities of Trp pyrrolase (TP), Lys ketoglutarate reductase (LKGR) and arginase were not significantly affected by varying levels of Trp, Lys and Arg respectively in the diet. TP has a cytosolic location and a Km of 0.2 mM for Trp; LKGR is mitochondrial and the Km for Lys is 7.3 mM; arginase is also mitochondrial and has a Km of 4.9 mM for arginine. Measurements of expired¹⁴CO₂, after injection of a tracer dose of¹⁴C amino acid, did allow estimates of requirement levels to be made. The values obtained from the oxidation studies reinforced the values obtained from the growth data but were not precise enough to justify using this method on its own.     

Dietary lysine requirement of juvenile gilthead seabream Sparus aurata L.*

The dietary lysine requirement of juvenile gilthead seabream was determined by the growth response of duplicate groups of fish (3.5 g initial weight) fed on six isonitrogenous (427 g kg^?1) and isolipidic (135 g kg^?1) diets containing graded levels of crystalline l ‐lysine HCl, with dietary lysine content ranging from 36.3 to 79.7 g kg^?1 of protein. The final indispensable amino acid profile of the diets except for lysine was formulated so as to resemble that of wild seabream whole body. Except for the reduced growth performance of fish groups fed the lysine‐deficient diets no other deficiency signs were apparent. Survival observed throughout the feeding period of 6 weeks was excellent. Weight gain (in %), specific growth rate, feed efficiency and daily protein deposition (DPD) were significantly improved in response to the increasing levels of dietary lysine up to 52.7 g kg^?1 of protein and remained nearly constant thereafter. Whole‐body protein content followed a similar pattern as growth parameters in relation to dietary lysine level. Non‐linear regression analysis of DPD against dietary lysine level using the four‐parameter saturation kinetic model indicated a lysine requirement of 50.4 g kg^?1 of protein for this species to support growth.