N-甲基-D,L-天门冬氨酸(NMA)对肥育猪脂肪沉积的影响及其机理

研究了不同剂量 N-甲基 -D,L-天门冬氨酸 ( NMA)对肥育猪脂肪代谢的影响。结果表明 ,饲粮中添加NMA 50 mg/ kg,肥育猪日增重提高 9.6 5% ( P<0 .0 1 ) ,胴体瘦肉率提高了 4 .0 8% ( P<0 .0 5) ,脂肪率降低3.50 % ( P<0 .0 1 ) ,皮下脂肪苹果酸脱氢酶总活力下降 1 8.6 4 % ( P<0 .0 5) ,葡萄糖 -6 -磷酸脱氢酶总活力下降 1 5.93% ( P<0 .0 5) ,异柠檬酸脱氢酶总活力下降 4 7.70 % ( P<0 .0 1 ) ,激素敏感脂肪酶活性提高 37.4 0 %( P<0 .0 3) ,脂肪组织中 c AMP含量提高 36 .6 8% ( P<0 .0 4 ) ,血清脂肪酶活性提高 1 1 5.1 5% ( P<0 .0 1 ) ,游离脂肪酸浓度上升 2 2 .6 4 % ( P<0 .0 1 )。据此认为 ,NMA可以通过调控脂肪代谢相关酶的活性 ,从而影响猪体脂肪代谢     

二丁酰环腺苷酸对猪胴体组成和肉品质的影响

通过皮下注射和饲料添加不同剂量dbcAMP进行饲养试验 ,研究其对肥育猪胴体组成和肉品质的影响。结果表明 :皮下注射 1.0mg/kg和饲料添加 2 0mg/kg对改善肥育猪的胴体组成和肉品质效果最好 ,眼肌面积分别提高31.99%和 36 .39% (P <0 .0 5 ) ;瘦肉率分别提高 12 .4 2 %和 11.94 % (P <0 .0 5 ) ;背膘厚分别降低 19.95 %和 2 0 .97%(P <0 .0 5 )。肌肉粗蛋白含量分别提高 10 .87%和 16 .5 4 % (P <0 .0 5 )。     

半胱胺和酵母铬对生长肥育猪生产性能和胴体品质的影响

试验选择25 kg左右的"杜长大"三元杂交猪96头,采用2×2析因设计分成4组,每组6个重复,每个重复4头。对照组喂基础饲粮,酵母铬(Cr)组在基础饲粮中添加酵母铬(生长期和肥育期分别添加Gr 200、300μg/kg),半胱胺(CS)组在基础饲粮中添加半胱胺(生长期和肥育期分别添加CS 120、170 mg/kg),复合组在基础饲粮中同时添加酵母铬和半胱胺(生长期和肥育期分别添加Gr 200μg+CS 120 mg/kg、Gr300μg+CS 170 mg/kg)。试验分生长期和肥育期两阶段进行,研究半胱胺和酵母铬对生长肥育猪生长性能、胴体和肌肉品质的影响。结果表明,生长肥育猪饲粮中分别添加半胱胺和酵母铬,一定程度上可改善生产性能,提高日增重、降低饲料/增重比;二者同时添加时有提高日增重的趋势,但统计分析差异不显著(P>0.05)。饲粮中分别或同时添加半胱胺和酵母铬对胴体肌肉品质也有一定的改善作用,但统计分析差异不显著(P>0.05)。     

对氨基苯胂酸对肥育猪生长性能和肉质的影响及其机理研究

1 2 0头“长嘉 (兴 )”肥育猪按体重、性别和遗传基础分成对照组和试验组 (每组三个重复 ,每个重复2 0头 ) ,分别饲喂含对氨基苯胂酸 (PAPAA)为 0和 70mg/kg的饲粮 ,进行 80天饲养试验 ,随后屠宰测定。结果表明 ,添加PAPAA使日增重提高 8.7% (P <0 .0 5) ,饲料转化率提高 1 1 .5% (P <0 .0 1 ) ,胴体瘦肉率提高 6.7% (P <0 .0 5) ,脂肪率降低 3.5% (P <0 .0 5) ,并发现眼肌面积提高 9.3% (P <0 .0 5)、大理石纹评分提高 5.0 % (P <0 .0 5)。残留测定显示 ;停药 4天后肌肉中砷含量达到国家卫生标准。组织分析发现 :饲粮中添加PAPAA使猪血清生长激素 (GH)浓度升高 4 4.0 % (P <0 .0 5)、胰岛素降低 2 3.4 % (P <0 .0 5) ;背最长肌、肾上腺和腺垂体cAMP含量分别提高 4 8.6%、30 .3%和 57.5% (P <0 .0 3)。上述结果揭示PA PAA似通过影响猪的内分泌系统机能而发挥其促进生长和改善胴体组成的效果     

半胱胺不同剂型对瘦肉猪生产性能的影响

选择体重 18 .0 4± 2 .5 1kg健康大长二元杂交仔猪 96头 ,随机分为 4组 ,分别为试验 1、2、3组和对照组 ,每组 4个重复 ,每个重复 6头。试验 1组在对照组日粮的基础上每隔 5天添加半胱胺 1次 ,剂量为 10 0mg/kg体重。试验 2和 3组在对照组日粮的基础上每隔 5天分别添加半胱胺糊化淀粉包被和半胱胺巯基磷酸二乙酯盐酸盐。试验结果表明 ,试验 1、2、3组日增重分别较对照组提高14 .74%、15 .61% (P <0 .0 1)和 7.5 9% (P <0 .0 5 )。料增重比试验1、2、3组日增重较对照组分别降低 9.77%、10 .2 3 %和 4.2 3 %。日粮补加不同剂型半胱胺对二元杂交猪生长有一定促进作用     

氧化三甲胺对生长肥育猪胴体组成的影响

本课题以“杜长嘉”三元杂交猪为试验对象 ,研究了氧化三甲胺 (TMAO)对生长肥育猪胴体组成的影响 ,并探讨了其作用机理。96头体重 32kg左右的“杜长嘉”三元杂交猪 ,按饲养试验要求分成 4组 ,每组 3个重复 ,每个重复 8头 ,公母各半。分别饲喂含 0 (对照 )、10 0 0 (1组 )、2 0 0 0 (2组 )、30 0 0 (3组 )mg kgTMAO的玉米 豆粕型饲粮。预试期 7天 ,正试期 6 6天。饲养试验结束后 ,随机从各组中挑选体重 78kg左右的试验猪 8头 (公母各半 ) ,共 32头 ,进行屠宰 ,测定胴体组成。屠宰试验表明 :1组的瘦肉率提高了 6 .15 % (P <0 .0 5 ) ,眼肌面积提高了 18.6 8% (P <0 .0 1) ,股四头肌比率提高了 8.6 %(P <0 .0 5 ) ,脂肪率降低了 18.4 % (P <0 .0 5 ) ,背膘厚降低了 2 1.6 3% (P <0 .0 5 )。血清分析显示 :1组的游离脂肪酸提高了 4 9.2 3% (P <0 .0 5 ) ,甘油三酯提高了 5 2 .4 6 % (P <0 .0 1) ,胰岛素含量降低了 32 .2 8% (P <0 .0 1) ,T4 含量提高了72 .5 5 % (P <0 .0 5 )。本研究结果提示 ,TMAO能明显改善生长肥育猪胴体组成     

甲基供体促仔猪生长的内分泌机制的探讨

试验将 72头始重为 1 0kg左右的杜长嘉仔猪随机分为 3组 ,以添加和不添加蛋氨酸为对照 ,试验组喂以添加 80 0mg/kg的甜菜碱。 3组的基础饲粮组成及营养水平相同 ,试验期为 3 6天。结果表明 ,与不添加蛋氨酸组相比 ,添加甜菜碱组猪的日增重和采食量分别提高了 1 1 .82 %(P <0 .0 5)和 8.71 %(P <0 .0 5) ,饲料转化率提高了 2 .79%(P <0 .0 5) ;与添加蛋氨酸组相比无显著差异 (P >0 .0 5)。此外 ,甜菜碱组肝脏中甜菜碱高半胱氨酸甲基转移酶 (BHMT)活较不添加蛋氨酸组高 61 .4 1 %(P <0 .0 5) ,较添加蛋氨酸组高 55.3 6%(P <0 .0 5) ,血样分析结果显示 ,添加甜菜碱组猪比不添加蛋氨酸组显著降低了血清尿素氮含量 (P <0 .0 1 )。提高了血清总铁结合力、GH和IGF -1水平 (P <0 .0 5)。但与添加蛋氨酸组相比 ,差异均不显著 (P >0 .0 5)。上述结果提示 ,甲基供体一方面通过肝脏BHMT酶的调控下为机体甲基化合成代谢提供甲基 ,发挥节约蛋氨酸的效应 ;另一方面通过增强机体GH和IGF -1的分泌 ,促进生长。     

N-甲基D,L-天冬氨酸对肥育猪生长性能和胴体品质的影响

本试验以杜长大肥育猪为试验对象 ,研究了N 甲基D ,L 天冬氨酸对其生长性能和胴体品质的影响。结果表明 ,在日粮中添加 50mg/kgN 甲基D ,L 天冬氨酸使肥育猪 ( 1 )日增重提高 9.31 % (P <0 .0 1 ) ,饲料转化率提高 7.1 6 % (P <0 .0 2 ) ;( 2 )胴体瘦肉率提高 6 .53% (P <0 .0 1 ) ,脂肪比率降低 1 1 .76 %(P <0 .0 1 ) ,背膘厚降低 1 9.72 % (P <0 .0 1 ) ,眼肌面积提高 2 1 .0 1 % (P <0 .0 4 ) ;( 3)背最长肌、股二头肌和半膜肌重量分别增加 1 1 .3% (P <0 .0 1 )、1 0 .0 9% (P <0 .0 1 )和 1 4 .4 4% (P <0 .0 1 )。     

半胱胺对肉仔鸡生产性能和胴体品质的影响

选择324只AA肉仔鸡随机分成6组,基础日粮中分别添加0、40、60、80、100、120mg/kg的半胱胺饲喂7周,结果表明:①日粮中添加60mg/kg半胱胺显著提高了3周末肉仔鸡的增重8.41%(P<0.05)和胸肌率13.6%(P<0.05)。②日粮中添加100mg/kg半胱胺显著提高了4～7周龄肉仔鸡的增重5.62%(P<0.05),降低料肉比12.97%(P<0.05),提高其屠宰率和胸肌率分别为4.1%(P<0.05)和12.4%(P<0.01),显著降低了肉仔鸡的腹脂率31.6%(P<0.05)。③日粮中添加60mg/kg半胱胺是改善1～3周龄肉仔鸡生产性能和胴体品质的最适剂量,100mg/kg半胱胺是改善生长全期肉仔鸡生产性能和胴体品质的最适添加剂量。     

甜菜碱对生长肥育猪生长性能的影响及其转甲基效应研究

以添加 1 0 0 0和 1 50 0mg/kg甜菜碱的饲粮分别饲喂生长肥育猪 ,均显著提高生长肥育猪日增重 ,其中以 1 0 0 0mg/kg组效果更为明显 ,生长期提高了 1 3.2 0 % (P <0 .0 1 ) ,肥育期提高了 5.68% (P <0 .0 5)。甜菜碱增加了猪肝脏甜菜碱高半胱氨酸甲基转移酶 (BHMT)活力 ,生长期总活力与比活力 1 50 0mg/kg组分别提高了 2 3.0 8% (P <0 .0 1 )和 1 8.1 8% (P <0 .0 5) ,肥育期则以 1 0 0 0mg/kg组更为明显 ,总活力与比活力分别提高 1 6.33% (P <0 .0 5)和 1 5.63% (P <0 .0 5)。肉碱含量分析表明 ,甜菜碱均显著提高了生长猪肝脏和肌肉游离肉碱的含量 ,而肥育期仅以肝脏游离肉碱及肌肉酸不溶肉碱含量上升显著     

大豆黄酮和半胱胺对生长肥育猪生长性能的影响

本试验研究了半胱胺(CS)和大豆黄酮(Da)对杜×长×大生长肥育猪生长性能和胴体性状的影响,结果表明:这两种物质均具有显著促进猪生长作用,且在猪生长期的促生长效果好于肥育期.二者能提高胴体瘦肉率4%以上,脂肪率下降9%.     

半胱胺对皖西白鹅增重及胴体品质的影响

在1日龄皖西白鹅的饲粮中添加100mg/kg的半胱胺,饲喂9周。试验结果表明:与对照组相比,试验组鹅体重提高了8.2%,饲料转化效率提高了11.9%,且差异显著(P<0.05)。在胴体品质上,试验组鹅胸肌重和后躯重分别比对照组增加10.5%和11.4%,腹脂下降14.8%,且差异极显著(P<0.01);双腿重和硬胸重分别提高了9.3%和8.3%,差异显著(P<0.05);半净膛重、全净膛重、翅重、翅根重和胸骨及肋骨重等指标试验组鹅也均有增加趋势,但与对照组差异均不显著(P>0.05)。试验结果表明,日粮中添加半胱胺可显著地提高了皖西白鹅增重及饲料转化效率,且对胴体品质有明显的改善作用。     

Dietary stimulation of the endogenous somatotropic axis in weaner and growerfinisher pigs using medium chain triglycerides and cysteamine hydrochloride

Background: Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides(MCT) and cysteamine hydrochloride(CSH) into the diets of young and growing pigs would stimulate the endogenous somatotropic axis to improve growth and performance.Results: In Experiment 1, weaner pigs were given either a 5 d dietary supplement of 5 % MCT(n = 8) or a control diet(n = 8). MCT increased the plasma concentration of growth hormone(GH; P 0.05) and the GH secretagogue,ghrelin(P 0.05). Additionally, the MCT treatment reduced scouring(P 0.05), maintained villous height in the small intestine(P 0.05) and stabilised daily weight gain(P 0.05), compared to the controls. Experiment 2compared the effects of 4 levels(0, 1, 3 and 6 % v/v) of MCT supplementation in grower-finisher male pigs, of approximately 35 kg live weight(n = 15 per treatment). Blood samples taken after 7 wk of treatment showed that the MCT supplementation increased circulating ghrelin(P 0.001), GH(P 0.01) and insulin(P 0.05)concentrations in a dose-dependent manner. Daily weight gain, feed intake and feed conversion ratio were not affected by the MCT diets. In Experiment 3, 64 female pigs of approximately 60 kg live weight were allocated to one of three dietary treatments: control(n = 20); 6 % MCT(n = 21); and 70 mg/kg CSH(n = 21). After 3 wk of supplementation, the MCT treated pigs had a higher plasma concentration of ghrelin compared to the control and CSH pigs(P 0.05). Plasma concentrations of GH and weight were not affected by any of the dietary treatments.Conclusions: Evidence is provided in Experiment 1 to support the use of dietary MCT supplements, perhaps acting via stimulation of somatotropic endocrine pathways, to minimise weaning-associated disorders such as slowing of growth and diarrhoea. In Experiments 2 and 3, although there was no effect on weight gain or feed conversion ratio in either experiment, MCT and CSH increased endocrine components of the somatotropic axis.     

Effect of dietary L-carnitine on growth performance and body composition in nursery and growing-finishing pigs.

Two experiments were conducted to determine the effect of dietary L-carnitine on growth performance and carcass composition of nursery and growing-finishing pigs. In Exp. 1,216 weanling pigs (initially 4.9 kg and 19 to 23 d of age) were used in a 35-d growth trial. Pigs were blocked by weight in a randomized complete block design (six pigs per pen and six pens per treatment). Four barrows and four gilts were used to determine initial carcass composition. L-Carnitine replaced ground corn in the control diets to provide 250, 500, 750, 1,000, or 1,250 ppm. On d 35, three barrows and three gilts per treatment (one pig/block) were killed to provide carcass compositions. L-Carnitine had no effect (P > 0.10) on growth, percentages of carcass CP and lipid, or daily protein accretion. However, daily lipid accretion tended to decrease and then return to values similar to those for control pigs (quadratic P < 0.10) with increasing dietary L-carnitine. In Exp. 2, 96 crossbred pigs (initially 34.0 kg BW) were used to investigate the effect of increasing dietary L-carnitine in growing-finishing pigs. Pigs (48 barrows and 48 gilts) were blocked by weight and sex in a randomized complete block design (two pigs/pen and eight pens/treatment). Dietary L-carnitine replaced cornstarch in the control diet to provide 25, 50, 75, 100, and 125 ppm in grower (34 to 56.7 kg; 1.0% lysine) and finisher (56.7 to 103 kg; 0.80% lysine) diets. At 103 kg, one pig/pen was slaughtered, and standard carcass measurements were obtained. Dietary L-carnitine did not influence growth performance (P > 0.10). However, increasing dietary carnitine decreased average and tenth-rib back-fat (quadratic, P < 0.10 and 0.05), and increased percentage lean and daily CP accretion rate (quadratic, P < 0.05). Break point analysis projected the optimal dosage to be between 49 and 64 ppm of L-carnitine for these carcass traits. It is concluded that dietary carnitine fed during the nursery or growing-finishing phase had no effect on growth performance; however, feeding 49 to 64 ppm of L-carnitine during the growing-finishing phase increased CP accretion and decreased tenth-rib backfat.     

Effects of pantothenic acid on growth performance and carcass characteristics of growing-finishing pigs fed diets with or without ractopamine hydrochloride

Two experiments evaluated effects of added pantothenic acid on performance of growing-finishing pigs. In Exp. 1, 156 pigs (PIC, initial BW = 25.7 kg) were used in a 3 x 2 x 2 factorial to evaluate the effects of added pantothenic acid (PA; 0, 22.5, or 45 ppm), ractopamine.HCl (RAC; 0 or 10 mg/kg), and sex on growth performance and carcass traits. Pigs were fed increasing PA from 25.7 to 123.6 kg (d 0 to 98) and RAC for the last 28 d before slaughter. Increasing the amount of added PA had no effect (P > 0.40) on ADG, ADFI, or G:F from d 0 to 70. A PA x sex interaction (P < 0.03) was observed for ADG and G:F from d 71 to 98. Increasing the amount of added PA increased ADG and G:F in gilts, but not in barrows. Increasing the amount of added PA had no effect (P > 0.38) on carcass traits. Added RAC increased (P < 0.01) ADG and G:F for d 71 to 98 and d 0 to 98 and increased (P < 0.01) LM area and percentage lean. In Exp. 2, 1,080 pigs (PIC, initial BW = 40.4 kg, final BW = 123.6 kg) were used to determine the effects of increasing PA on growth performance and carcass characteristics of growing-finishing pigs reared in a commercial finishing facility. Pigs were fed 0, 22.5, 45.0, or 90 mg/kg of added PA. Increasing the amount of added PA had no effect (P > 0.45) on ADG, ADFI, or G:F, and no differences were observed (P > 0.07) for carcass traits. In summary, adding dietary PA to diets during the growing-finishing phase did not provide any advantages in growth performance or carcass composition of growing-finishing pigs. Furthermore, it appears that the pantothenic acid in corn and soybean meal may be sufficient to meet the requirements of 25- to 120-kg pigs.     

Effects of modified tall oil and creatine monohydrate on growth performance, carcass characteristics, and meat quality of growing-finishing pigs

The effects of feeding modified tall oil (MTO) and creatine monohydrate (CMH) on growing-finishing pig growth performance, carcass characteristics, and meat quality were determined. Eighty cross-bred barrows (initially 45.4 kg) were allotted randomly to one of four dietary treatments by weight and ancestry. The experiment was arranged as a 2 x 2 factorial with two levels of MTO (0 or 0.50%), which were fed throughout the growing-finishing period, and two levels of CMH (0 or 25 g/d), which were fed for the final 10 d before slaughter. The corn-soybean meal diets were fed in two phases (45.4 to 78.9 kg and 78.9 to 117.5 kg BW). When CMH was added to the diet in place of corn, average BW was 107.5 kg. Feeding MTO increased (P < 0.05) ADG and gain:feed ratio (G/F) during the 45.4- to 78.9-kg growth interval and tended to improve (P = 0.10) G/F during the 45.4- to 107.5-kg growth interval. Dietary treatment did not affect (P > 0.15) growth performance during the 78.9- to 107.5-kg growth interval. Modified tall oil increased (P = 0.02) G/F during the 10-d CMH supplementation period, and CMH numerically (P = 0.11) increased ADG and G/F. Supplementation of CMH did not affect (P > 0.20) any measured carcass characteristic or measures of meat quality at 24 h or 14 d postmortem. Feeding MTO reduced average back-fat (P = 0.05) and 10th rib backfat (P = 0.01) but did not affect (P > 0.10) other measured carcass characteristics or measures of meat quality at 24 h postmortem. Modified tall oil increased (P = 0.02) L* values (lightness) and tended to increase (P < 0.10) thawing and cooking losses of longissimus muscle chops at 14 d postmortem. These data demonstrate that MTO improves growth performance and reduces backfat in growing-finishing pigs, but supplementation of CMH, under the conditions of this experiment, was not beneficial for growing-finishing pigs.     

Ractopamine对大约克猪蛋白质和脂肪代谢的影响

用添加２０ｍｇ／ｋｇＲａｃｔｏｐａｍｉｎｅ的饲粮饲喂纯种大约克肥育猪，发现半腱肌ＤＮＡ含量降低１４％（Ｐ＜０．０１），ＲＮＡ含量升高７．７％（Ｐ＜０．０１），背最长肌ＤＮＡ含量下降７％（Ｐ＜０．０１），ＲＮＡ上升５．５％（Ｐ＜０．０１），且两种肌肉中的ＲＮＡ／ＤＮＡ均呈升高趋势；背最长肌中酪氨酸、苏氨酸和蛋氨酸含量分别降低２５％（Ｐ＜０．０５）、９％（Ｐ＜０．０１）和１７％（Ｐ＜０．０５），而甘氨酸和丙氨酸含量分别上升１５％（Ｐ＜０．０５）和８％（Ｐ＜０．０５），肝组织中天冬氨酸和异亮氨酸分别提高１１．６％（Ｐ＜０．０１）和１２％（Ｐ＜０．０１）；此外背最长肌肌原纤维的降解系数（ＭＦＩ）明显降低，血清尿素氮下降１６．６％（Ｐ＜０．０５）。同时还发现Ｒａｃｔｏｐａｍｉｎｅ使皮下脂肪中异柠檬酸脱氢酶活力降低２７％（Ｐ＜０．０１），血清脂肪酶活力升高１２．２％（Ｐ＜０．０５），血清胆固醇降低２３．５％（Ｐ＜０．０５）。上述结果显示：Ｒａｃｔｏｐａｍｉｎｅ可促进体内蛋白质的合成和脂肪的分解，而抑制蛋白质的降解和脂肪的合成     

高温高湿环境下饲粮能量水平对生长肥育猪生长性能、血清生化指标和肉品质的影响

本试验旨在研究不同饲粮消化能水平在高温高湿饲养环境下对生长肥育猪生长性能、血清生化指标和肉品质的影响,以确定生长肥育猪适宜的消化能水平。选取平均初始体重为(40.0±2.0)kg的健康“杜×长×大”生长猪50头,随机分为5个组,每个组10个重复(7头公猪,3头母猪),每个重复1头猪。5个组试验猪分别饲喂消化能水平为13.68、13.88、14.09、14.30和14.51 MJ/kg的饲粮,试验期为90 d。结果表明:1)在高温高湿环境下,随着饲粮消化能水平的提高,试验猪生长期、育肥期及试验全期的平均日采食量呈下降趋势,而平均日增重(ADG)呈先升高后降低、料重比呈先降低后升高的趋势。猪生长期和全期的ADG与饲粮消化能水平的曲线方程分别为Y1=-878.02X^2+24708.94X-173289.53(R^2=0.69,P<0.01)和Y2=-436.56X^2+12276.96X-85600.33(R^2=0.54,P<0.05),当ADG达到最大时,对应的饲粮消化能水平分别为14.07和14.06 MJ/kg。2)饲粮消化能水平对生长肥育猪血清总蛋白、高密度脂蛋白胆固醇和免疫球蛋白G含量存在显著影响(P<0.05),并且以14.09 MJ/kg消化能组最高(P<0.05)。3)饲粮消化能水平对生长肥育猪血清脂蛋白脂肪酶、脂肪酶(LPS)活性分别有极显著(P<0.01)和显著性(P<0.05)影响,而对血清苹果酸脱氢酶活性以及脂联素和生长激素含量没有显著影响(P>0.05);猪血清LPS活性与饲粮消化能水平的曲线方程为Y3=133.00X^2-3761.26X+26664.78(R^2=0.83,P<0.05),当血清LPS活性最低时,对应饲粮消化能水平为14.14 MJ/kg。4)随着饲粮消化能水平的提高,生长育肥猪的皮脂率显著提高(P<0.05),肌肉滴水损失和剪切力显著降低(P<0.05),并以14.09 MJ/kg消化能组的肉品质最优,其滴水损失和剪切力显著低于13.68 MJ/kg消化能组(P<0.05);猪肉滴水损失和剪切力与饲粮消化能水平的曲线方程分别为Y4=0.70X^2-19.92X+143.25(R^2=0.96,P<0.05)和Y5=2.88X^2-82.20X+590.36(R^2=0.99,P<0.05),当肌肉滴水损失、剪切力达到最低时,对应的饲粮消化能水平分别为14.23和14.27 MJ/kg。     

半胱胺对奶牛产奶量及血浆生长抑素、生长激素水平的影响

选用１０ 头处于泌乳中期的荷斯坦牛进行自身对照试验。对照期饲喂基础日粮,试验期在基础日粮中添加半胱胺。每隔５ 天一次,剂量为１００ｍｇ／ｋｇ 体重,共喂３ 次。结果表明,试验期奶牛日产奶量比对照期提高７ ．６ ％ （ 对照期１４ ．５ ±３ ．９ｋｇ／ 头,试验期１５ ．６ ±４ ．３ｋｇ／ 头Ｐ＜ ０ ．０５） ;奶牛采食量无明显变化,试验期饲料转化率比对照期明显提高（ 对照期０ ．３２ ±０ ．０１ ,试验期０ ．３０ ±０ ．０２ ,Ｐ＜ ０ ．０１） ;与对照期相比,试验期奶牛血浆生长抑素（ＳＳ） 水平明显下降（ 对照期１ ．２１ ±０ ．３４ｎｇ／ｍｌ,试验期０ ．１４ ±０ ．０５ｎｇ／ｍｌ,Ｐ（ ＜ ０ ．０１） ,生长激素含量显著提高（ 对照期１ ．３３ ±０ ．２６ｎｇ／ｍｌ,试验期１ ．７７ ±０ ．２９ｎｇ／ｍｌ,Ｐ＜ ０ ．０５） ;半胱胺对牛乳脂率无明显影响（ 对照期２ ．１６ ±０ ．５８ ,试验期２ ．５３ ±０ ．０６） 。以上结果表明,半胱胺能明显提高奶牛产奶量,而抑制体内生长抑素,提高内源性生长激素水平,可能为其主要的作用机制。