Effect of rumen‐protected choline and methionine on physiological and metabolic disorders and reproductive indices of dairy cows

The objective of this study was to investigate the effect of feeding different levels of ruminally protected methionine and choline on the incidence of physiological and metabolic disorders, production, and some of the reproductive indices of Holstein dairy cows. Forty Holstein dairy cows in their first and second lactation were used from 4‐week pre‐partum through 20‐week post‐partum and randomly assigned to receive one of the following treatments: 18 g/day of rumen‐protected methionine (RPM), 60 g/day of rumen‐protected choline (RPC), 18 g/day of RPM + 60 g/day of RPC, and neither supplement (control). The treatments significantly affected services per conception and open days of lactating dairy cows (p < 0.05), but did not affect significantly on days to first oestrus and number of pregnant cows. RPM + RPC‐fed cows had the lowest open days, days to first oestrus and services per conception compared with other groups. The effect of treatments was significant on the incidence of metabolic and physiological problems except for foot/leg problems. Cows fed RPM+RPC had the lowest health problems compared with other groups (p < 0.05). Results indicate that the supplementation of RPM and RPC can improve reproductive performance and health status of dairy cows.     

Effect of dietary methionine on growth performance and insulin‐like growth factor‐I mRNA expression of growing meat rabbits

An experiment was conducted to determine the effects of different amounts of dietary methionine on growth performance, serum protein, growth hormone (GH), insulin‐like growth factor‐I (IGF‐I) concentrations and IGF‐I mRNA expression of growing meat rabbits. One hundred weaned growing meat rabbits were allocated to individual cages and randomly divided into five groups. The methionine addition concentrations of the five groups were 0, 2, 4, 6 and 8 g/kg diet (as‐fed basis) and sulphur amino acids (SAA) concentrations ranging from 3.8 to 11.6 g/kg diet, respectively. The results obtained were as follows: the average daily gain of 2, 4 and 6 g/kg diet groups was higher than that of 0 g/kg diet group (p < 0.01). The feed gain ratio of the 4 g/kg diet group was lower than those of 0 and 8 g/kg diet group (p < 0.01). Methionine concentrations did not affect serum urea nitrogen, total protein, insulin and IGF‐I concentration (p > 0.05). The quadratic effects of methionine on the serum concentration of albumin (Alb) and GH were obtained (p = 0.013, p = 0.018). The quadratic effect of methionine amount on IGF‐I mRNA expression was obtained (p = 0.045). The serum concentration of Alb of the 4 g/kg diet group was higher than those of 0 and 8 g/kg diet group (p < 0.01). The serum concentration of GH of 8 g/kg diet group was higher than that of the 0 g/kg diet group (p < 0.05). The liver IGF‐I mRNA expression of 4 g/kg diet group was higher than those of the 0 and 8 g/kg diet group (p < 0.05). Providing a diet mainly consisted of corn, wheat bran and peanut vine, the optimum dietary methionine addition concentration and SAA concentration for a weaner to 2‐month‐old growing meat rabbits were shown to be 2 and 5.7 g/kg diet respectively.     

复相乳化法制备明胶微囊蛋氨酸的工艺初探

以明胶和羧甲基纤维素钠为包囊材料,蛋氨酸为芯材采用复相乳化法制备蛋氨酸微胶囊。应用均匀实验设计分析了微胶囊制备过程主要影响因素及适宜的工艺条件,得出明胶溶液浓度对微囊的形成影响较大,优化参数得出蛋氨酸微胶囊载药量为61.30%。     

不同粗蛋白和氨基酸组合日粮对实验兔氮代谢和免疫功能的影响

选用100日龄成年日本大耳白兔36只,随机分为6组（Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ和Ⅵ组）,分别喂以6种不同粗蛋白和氨基酸组合的日粮。其中Ⅰ-Ⅲ组日粮粗蛋白水平为12％,赖氨酸含量分别为0．72％,0．9％和1．08％,含硫氨基酸含量分别为0．52％,0．65％和0．78％：Ⅳ—Ⅵ组日粮粗蛋白水平为16％,赖氨酸与含硫氨基酸组成分别与Ⅰ-Ⅲ组相同。通过饲养试验、氮代谢试验和免疫学实验。观察这6种粗蛋白和氨基酸组合日粮对实验兔的氮代谢和免疫功能的影响。试验结果表明,动物的日增重和氮利用率以Ⅲ、Ⅳ组最高,Ⅰ、Ⅵ组最低,Ⅲ、Ⅳ组分别与Ⅰ、Ⅵ差异显著（P〈0．01）,但Ⅲ组的总氮排泄量明显低于Ⅳ组（P〈0．01）。Ⅲ、Ⅳ组动物的脾脏指数和胸腺指数也都高于其他4组动物,Ⅳ组动物的脾脏指数分别与Ⅰ、Ⅱ、Ⅴ和Ⅵ组差异显著（P〈0．01）。抗卵苛白蛋白抗体阳性的动物数以Ⅲ组最多,分别与Ⅱ、Ⅴ和Ⅵ组差异显著（P〈0．05）。血清总蛋白含量随日粮氨基酸水平提高有上升趋势,血清尿素氮含量以Ⅴ和Ⅵ组最高,与其他各组差异显著（P〈0．01,P〈0．05）。综上所述,Ⅲ、Ⅳ组日粮粗蛋白和氨基酸组合比较适宜,考虑到Ⅳ组氮排放量较高,故以Ⅲ组最佳。     

日粮蛋氨酸水平对大骨鸡肌肉SLC12A5、 Musclin mRNA表达影响的研究

试验旨在研究日粮蛋氨酸水平大骨鸡腿肌和胸肌SLC12A5、Musclin mRNA表达量的影响.选择240只16周龄公鸡,随机分为3组,每组10个重复,每个重复8只.H组、M组和L组日粮中蛋氨酸(Met)水平分别为0.42％、0.34％、0.25％,其中M组为对照组.试验期8w.结果 显示,H组各周龄公鸡血清Met含量...     

不同蛋氨酸水平对泰和乌骨鸡氮存留率的影响研究

采用氮平衡试验研究了5个不同蛋氨酸水平对生长期泰和乌骨鸡(4、8、12周龄)氮存留率。结果表明：4周龄时,泰和乌骨鸡公、母鸡均以0．44％的蛋氨酸的氮存留率最佳;8周龄时,泰和乌骨鸡公鸡以0.35％,母鸡以0．31％的蛋氨酸的氮存留率最佳;12周龄时,泰和鸡公鸡以0．26％,母鸡以0．24％的蛋氨酸的氮存留率最佳。     

Supplementing rainbow trout (Oncorhynchus mykiss) broodstock diets with choline and methionine improves growth in offspring

Nutritional programming represents the mechanism through which broodstock feeding strategies have lifelong effects on the offspring generation. The objective of this study was to determine whether supplementing rainbow trout, Oncorhynchus mykiss broodstock diets with choline and methionine affects offspring growth performance. Experimental diets were produced by top-dressing a commercial broodstock diet with (a) 12,000 ppm methionine, (b) 7,400 ppm choline, (c) 12,000 ppm methionine and 7,400 ppm choline, or (d) water (control). Six rainbow trout families were fed experimental diets beginning 18 months post-hatch through spawning; the offspring consumed a commercial diet. The broodstock diet did not affect maternal body weight, body condition, egg size, or egg yield (p > .05). Eggs from choline-treated broodstock contained 10% more choline than control eggs (p < .05). Offspring from choline-treated broodstock were smaller than controls at 146 days post-hatch (dph) (p < .05). At the final harvest (439 dph), offspring from the control broodstock weighed 12–18% less than offspring from broodstock consuming the supplemented diets (p < .05). However, there was a significant diet-by-family interaction on offspring growth (p < .05); supplemented diets improved performance in three of the six broodstock families. These findings indicate that supplementing broodstock diets with methionine and choline causes a nutritional programming effect that benefits growth in offspring.     

Methionine promotes the development of hair follicles via the Wnt/β-catenin signalling pathway in Rex rabbits

To investigate the effect and molecular mechanism of methionine (Met) on the growth of hair follicles (HFs) in Rex rabbits. A total of 200 weaning Rex rabbits were divided into four groups and fed varying levels of Met-supplemented diets. We measured the HF density on dorsal skin and the Wnt/β-catenin pathway protein expression level. Meanwhile, whole HFs were isolated from Rex rabbit skins and cultured with Met in vitro to measure hair shaft growth. The relationship between Met and the Wnt/β-catenin signalling pathway was also characterized by using the Wnt/β-catenin signalling inhibitor, XAV-939. The results showed that the addition of dietary Met could significantly increase the HF density on dorsal skin (p < .05) and enhance the protein expression level of Wnt10b (p < .05), β-catenin (p < .05) and DSH (p < .05). Methionine stimulation could also prolong the hair shafts growth in vitro (p < .05). And inhibition of Wnt/β-catenin signalling using XAV-939 could eliminate this phenomenon. In summary, Met can increase the density of HFs on dorsal skin in vitro and prolong the hair shaft growth of HFs in vivo via the Wnt/β-catenin signalling pathway.     

新杨绿壳蛋鸡蛋氨酸需要量的研究

本试验通过研究蛋氨酸对绿壳蛋鸡的生产性能、蛋品质以及血清总蛋白、白蛋白、尿素氮和尿酸含量等指标的影响,旨在得出新杨绿壳蛋鸡(34～ 43周龄)蛋氨酸适宜的需要量.选取1 440羽34周龄的新杨绿壳蛋鸡随机分成6组(每组4个重复,每个重复60羽),对照组饲喂蛋氨酸水平为0.24％的玉米-豆粕型基础饲粮,试验组分别饲喂蛋氨酸水平为0.27％、0.30％、0.33％、0.36％和0.39％的饲粮.试验期为10周.结果表明:1)0.27％蛋氨酸水平组的产蛋率较0.24％和0.39％蛋氨酸水平组分别显著提高了3.75％和3.97％ (P＜0.05);0.27％蛋氨酸水平组的料蛋比较对照组和0.30％、0.33％、0.36％和0.39％蛋氨酸水平组分别显著降低了2.99％、2.40％、2.40％、3.56％和6.88％ (P＜0.05);0.33％蛋氨酸水平组的平均蛋重显著高于0.24％、0.36％和0.39％蛋氨酸水平组(P＜0.05).2)0.30％蛋氨酸水平组的蛋白高度和哈氏单位比0.39％蛋氨酸水平组分别显著提高了19.31％和9.44％ (P＜0.05).3)0.27％蛋氨酸水平组血清尿酸含量较0.24％、0.36％和0.39％蛋氨酸水平组分别显著降低了24.36％、23.21％和22.60％(P＜0.05).4)0.27％蛋氨酸水平组天冬氨酸、半胱氨酸和蛋氨酸的表观消化率显著高于0.39％蛋氨酸水平组(P＜0.05).5)二次曲线分析表明,以产蛋率为评价指标,产蛋期绿壳蛋鸡蛋氨酸需要量为0.26％;以料蛋比为评价指标,产蛋期绿壳蛋鸡蛋氨酸需要量为0.28％;以蛋白高度为评价指标,产蛋期绿壳蛋鸡蛋氨酸需要量为0.29％.结果提示,饲粮中适宜水平的蛋氨酸能够提高产蛋期绿壳蛋鸡机体蛋白质利用率,提高蛋鸡生产性能和改善蛋品质.新杨绿壳蛋鸡(34 ～ 43周龄)玉米-豆粕型饲粮蛋氨酸适宜需要量为0.26％ ～ 0.29％.