黄霉素对黄河鲤鱼生长性能和体成分的影响

研究了饲料中添加不同水平黄霉素(2、4、6和8 mg/kg)对黄河鲤鱼生长性能和体成分的影响.结果表明:试验组饵料系数低于对照组;试验组黄河鲤鱼的生物学综合评价高于对照组,其中添加6mg/kg黄霉素的试验组黄河鲤鱼的生物学综合评价最好;全鱼水分、粗蛋白质、粗脂肪和灰分含量组间差异不显著(P＞0.05).     

α-硫辛酸对育肥猪生产性能和抗氧化功能的影响

研究日粮中添加α-硫辛酸对肥育猪生产性能和抗氧化功能的影响.对照组饲喂基础日粮,试验组在基础日粮中分别添加300、600和900 mg/kg的旷硫辛酸,试验期28 d.结果表明:与对照组相比,添加600、900 mg/kgα-硫辛酸降低了平均日增重(P＜0.05)和平均日采食量(P＜0.01),而各组料重比差异均不显著(P＞0.05);900mg/kgα-硫辛酸组总抗氧化能力增加显著(P＜0.05),谷胱甘肽过氧化物酶活性极显著增强(P＜0.01).α-硫辛酸添加组血清中丙二醛含量均显著降低(P＜0.05).α-硫辛酸的适宜添加水平为600 mg/kg.     

大豆异黄酮对樱桃谷鸭生长和屠宰性能的影响

选用健康1日龄樱桃谷SM2商品代雏鸭128只,随机分为4组,公、母各半.对照组饲喂基础日粮,试验I、Ⅱ、Ⅲ组日粮是在基础日粮中分别添加5、10和15 mg/kg的大豆异黄酮,于42日龄屠宰.结果表明:①试验组公鸭、母鸭每周平均体重均显著高于或高于对照组,试验Ⅱ组的平均体重显著高于其他各组(P＜0.05).大豆异黄酮对樱桃谷鸭母鸭和公鸭的生长具有明显的促进作用,而且其作用效果呈现剂量效应,以10 mg/kg添加水平效果最为明显.②试验Ⅱ组母鸭的屠宰率和胸肌率高于其他各组(P＞0.05);母鸭和公鸭的腹脂率均显著低于其他各组(P＜0.05).试验Ⅲ组母鸭的腿肌率显著高于其他各组(P＜0.05).试验组间母鸭的皮脂率差异不显著(P＞0.05);但均显著低于对照组(P＜0.05),试验Ⅲ组母鸭的皮脂率最低.试验Ⅲ组公鸭的屠宰率、胸肌率和腿肌率高于其他各组(P＞0.05),试验I、Ⅲ组公鸭的腹脂率也显著低于对照组(P＜0.05),试验Ⅱ组公鸭的皮脂率显著低于其他各组(P＜0.05).大豆异黄酮发挥了降脂作用,且以10 mg/kg的作用最为明显.     

大蒜素对肉仔鸡脂肪代谢及相关基因表达的影响

探讨大蒜素对肉仔鸡脂类代谢及相关基因表达的影响,为揭示大蒜素调节动物脂肪沉积的机理作依据。试验选取体重相近、体格健壮的1日龄AA肉仔鸡(公)96只,随机分成4组,每组设4个重复,每个重复6只鸡。试验期为42d。在各组基础饲料中分别添加0、200、400、600mg/kg的大蒜素。结果表明,添加400和600mg/kg大蒜素的处理组与对照组比较,肉仔鸡腹脂率和肝脂率显著降低(P0.05);而添加200、400及600mg/kg大蒜素的处理组与对照组比,皮下脂肪厚度和肌间脂肪厚度没有显著的差异(P0.05),但有下降的趋势。400mg/kg组和600mg/kg组的甘油三酯、总胆固醇及低密度脂蛋白的含量显著下降(P0.05);而高密度脂蛋白水平则呈现出显著的提高(P0.05)。各浓度添加大蒜素组的游离脂肪酸的水平与对照组相比而言,有降低的趋势,但差异不显著(P0.05)。添加400mg/kg或600mg/kg大蒜素可显著降低AA肉仔鸡肝脏中的乙酰辅酶A羧化酶、脂肪酸合成酶的mRNA表达水平(P0.05);添加600mg/kg大蒜素组的肉仔鸡肝脏脂蛋白脂酶mRNA水平显著上调(P0.05)。添加600mg/kg大蒜素的肉仔鸡腹脂中乙酰辅酶A羧化酶mRNA表达水平显著低于对照组(P0.05),脂蛋白脂酶mRNA水平则显著上升(P0.05)。大蒜素对肉仔鸡腹脂脂肪酸合成酶mRNA水平无显著影响。     

棉子糖对草鱼生长性能与肠道黏膜形态的影响

以基础饲料作为对照组,在基础饲料中分别添加200、400、800、1 200和2 000mg/kg棉子糖的组作为5个试验组,以研究棉子糖对草鱼生长性能与肠道黏膜形态的影响。结果显示:(1)添加棉子糖能够提高草鱼的特定生长率,降低饵料系数,其中1 200mg/kg组与其余各组相比差异显著(P<0.05)。(2)各试验组肠道皱襞高度均高于对照组,除800、2 000mg/kg组外,其他试验组均显著高于对照组(P<0.05);200mg/kg组、1 200mg/kg组微绒毛高度显著高于对照组(P<0.05);除2 000mg/kg组外,其他试验组微绒毛密度均显著高于对照组(P<0.05)。本试验条件下,饲料中棉子糖最适添加量为1 200mg/kg。     

黄霉素和大蒜素对鲫鱼生长性能及生理状况的影响

在基础饲料中分别添加10 mg/kg黄霉素和200 mg/kg大蒜素,研究其对鲫鱼生长性能、血清生化指标及抗氧化能力的影响.结果表明:黄霉素和大蒜素对鲫鱼的生长性能无显著影响(P＞0.05).大蒜素组血红蛋白显著高于其他两组(P＜0.05),血清白蛋白、球蛋白、甘油三酯显著高于黄霉素组(P＜0.05),血清葡萄糖显著低于对照组(P＜0.05),血清总胆固醇、肝胰脏SOD活性显著高于对照组(P＜0.05);大蒜素可改善其生理状况.     

外源复合酶对异育银鲫生长及肠道消化酶活性的影响

采用单因素梯度设计,在基础饲料中分别添加0、100、200和400 mg/kg的复合酶配制试验饲料,饲养初始体重6.71 g左右的异育银鲫56 d后,测定生长特性、肠道蛋白酶、淀粉酶及木聚糖酶活性.结果表明,添加200 mg/kg复合酶组异育银鲫的增重率和特定生长率最大,显著大于对照组(P＜0.05),同时该组异育银鲫的饲料系数最低,显著低于对照组(P＜0.05).从肠道分布的部位来看,前肠3种消化酶活性均高于后肠.     

乳化剂对育肥猪肌肉品质和抗氧化性能的影响

探讨乳化剂对育肥猪肌肉品质和抗氧化性能的影响.结果表明:在育肥猪日粮中添加200 mg/kg乳化剂,对肌肉颜色、pH值、失水率和熟肉率无显著影响(P＞0.05),但试验组滴水损失降低显著(P＜0.05),肌内脂肪提高显著(P＜0.05).与对照组相比,试验组肌肉超氧化物歧化酶活力增加(P＞0.05),丙二醛含量下降(P＜0.05).     

对虾饲料中木薯粉替代小麦粉对对虾生长性能的影响

研究饲料中以不同水平的木薯粉替代配方中相应的高筋小麦粉对凡纳滨对虾的生长速度、成活率和饵料系数的影响.结果表明:替代水平3％的组,凡纳滨对虾增重率最高(3 401.25％),但与对照组比差异不显著(P＞0.05);随着木薯粉替代水平的提高,增重率呈下降趋势且均显著低于对照组(P＜0.05),替代水平达12％的组,增重率降至最低(3 170.00％).试验组凡纳滨对虾成活率均显著高于对照组(P＜0.05).添加木薯粉可以降低凡纳滨对虾的饵料系数,3％组饵料系数(1.12)显著低于对照组(P＜0.05).     

L-肉碱对异育银鲫生长性能、液生化指标和肌肉氨基酸组成的影响

研究L-肉碱对异育银鲫生长性能、血液生化指标和肌肉氨基酸组成的影响.L-肉碱在基础饵料中的添加水平分别为0、50、100、150、200、250 mg/kg,饲养试验时间为40 d.结果表明:L-肉碱可促进鲫鱼生长发育,200 mg/kg组的鱼体的平均尾增重高于对照组13.23%(P<0.05),饵料系数降低12.82%(P<0.05);异育银鲫血清中的生长激素(GH)含量提高,其中200 mg/kg组高于对照组8.49%(P<0.05),150 mg/kg组的血清总胆固醇(CHO)和尿素氮(BUN)的含量分别降低10.85%、16.67%(P<0.05),200 mg/kg和250 mg/kg组CHO和BUN降幅均达到极显著水平(P<0.01);各试验组鱼体肌肉氨基酸含量和组成均有不同程度改善.添加水平为200 mg/kg时效果最好.     

动物性食品中环境激素对人体的影响及其防治

文中分别介绍了环境激素的定义、激素与环境激素间的关系,以及动物性食品中所包含的环境激素种类,通过分析动物性食品中环境激素的污染途径及其对人体的影响,提出了控制措施以增强人们对其危害的重视,并减少环境激素对人体损害,有利于控制环境激素在动物性食品中的含量。     

蜂王浆对雌性大鼠生长发育的影响

目的：探讨高剂量蜂王浆对雌性大鼠生长发育的影响。方法：实验组大鼠按3 g/（200 g·d）（以体质量计,下同）灌胃新鲜的蜂王浆溶液,对照组按3 mL/（200 g·d）灌胃生理盐水,4 周后,停止灌胃,继续饲养2 周。每两周解剖一批大鼠,称质量计算心、肝、脾、肺、肾、肾上腺、子宫、卵巢脏器系数,用放射免疫技术检测血清雌二醇（estradiol,E2）、促卵泡素（follicle stimulating hormone,FSH）、促黄体素（luteinizing hormone,LH）、孕激素（progestrone,P）含量,实时定量聚合酶链式反应（real-timepolymerase chain reaction,real-time PCR）检测卵巢和子宫中雌激素受体α（estrogen receptor α,ERα）、雌激素受体β（estrogen receptor β,ERβ）、促卵泡素受体（follicle stimulating hormone receptor,FSHR）、促黄体素受体（luteinizing hormone recepter,LHR）、孕激素受体（progestrone receptor,PR）mRNA表达量。结果：灌胃2 周,实验组大鼠体质量、主要脏器系数、血清主要性激素含量及其卵巢和子宫中受体表达量与对照组相比均无显著差异;灌胃4 周,实验组大鼠体质量显著低于对照组,实验组血清E2显著高于对照组,实验组卵巢PR mRNA表达量显著高于对照组,实验组子宫中ERα、ERβ、PR mRNA表达量显著高于对照组。实验组与对照组脏器系数无显著差异;停止灌胃2 周后,实验组大鼠体质量、主要脏器系数、血清主要性激素含量与对照组相比均无显著差异,实验组卵巢中FSHR、ERβ、PR mRNA表达量显著高于对照组,实验组子宫中ERα、ERβ、FSHR和PR mRNA表达量显著高于对照组。结论：高剂量的蜂王浆在一定程度上影响雌性大鼠的生长发育。     

Intravaginal instillation of gonadotropin-releasing hormone analogues with an absorption enhancer induced a surge of luteinizing hormone in lactating dairy cows

Our objectives were to evaluate circulating LH concentrations after intravaginal (IVG) instillation of GnRH analogs in lactating dairy cows. In 2 experiments, lactating Holstein cows (experiment 1: n = 32; experiment 2: n = 47) received the experimental treatments 48 h after the first of 2 PGF_2α treatments given 12 h apart and 7 d after a modified Ovsynch protocol (GnRH at ?7 d, PGF_2α at ?24 h, PGF_2α at ?56 h, GnRH at 0 h). In experiment 1, cows were stratified by parity and randomly allocated to receive the following treatments: 2 mL of saline IVG (SAL, n = 6), 100 µg of gonadorelin (Gon) i.m. (G100-IM, n = 5), and 100 (G100, n = 7), 500 (G500, n = 8), or 1,000 µg of Gon IVG (G1000, n = 7). In experiment 2, treatments were SAL (n = 8), G100-IM (n = 8), G1000 (n = 7), 1,000 µg of Gon plus 10% citric acid (CA) IVG (G1000CA, n = 8), 80 µg of buserelin IVG (B80, n = 8), and 80 µg of buserelin plus 10% CA IVG (B80CA, n = 8). In both experiments, blood was collected every 15 min from ?15 min to 4 h, and every 30 min from 4 to 6 h after treatment. Data for area under the curve (AUC), mean LH concentrations, and time to maximum LH concentration were analyzed by ANOVA with (mean LH only) or without repeated measures using PROC MIXED of SAS (version 9.4, SAS Institute Inc., Cary, NC). The proportion of cows with a surge of LH was evaluated with Fisher's exact test using PROC FREQ of SAS. In both experiments, LH concentrations were affected by treatment, time, and the treatment by time interaction. In experiment 1, the AUC for LH and maximum LH concentration were greatest for the G100-IM treatment and were greater for the G1000 than for the SAL and G500 treatments. The proportion of cows with an observed surge of LH was 100 and 0% for cows that received Gon i.m. and IVG, respectively. In experiment 2, the AUC and maximum LH concentrations were greater for the G100-IM, G1000CA, and B80CA treatments than for the other IVG treatments. The proportion of cows with a surge of LH differed by treatment (SAL = 0%, G100-IM = 100%, G1000 = 14%, G1000CA = 88%, B80 = 13%, and B80CA = 100%). For the treatments with a surge of LH, time to maximum concentration of LH was the shortest for the G100-IM treatment, intermediate for the G1000CA treatment, and the longest for cows in the B80CA treatment. In conclusion, Gon (up to 1,000 µg) absorption through intact vaginal epithelium after a single IVG instillation was insufficient to elicit a surge of LH of normal magnitude. Conversely, IVG instillation of 1,000 µg of Gon and 80 µg of buserelin with the addition of citric acid as absorption enhancer resulted in a surge of LH of similar characteristics than that induced after i.m. injection of 100 µg of Gon.     

Effect of elevating luteinizing hormone action using low doses of human chorionic gonadotropin on double ovulation,follicle dynamics,and circulating follicle-stimulating hormone in lactating dairy cows

Double ovulation and twin pregnancy are undesirable traits in dairy cattle. Based on previous physiological observations, we tested the hypothesis that increased LH action [low-dose human chorionic gonadotropin (hCG)] before the expected time of diameter deviation would change circulating FSH concentrations, maximum size of the second largest (F2) and third largest (F3) follicles, and frequency of multiple ovulations in lactating dairy cows with minimal progesterone (P4) concentrations. In replicate 1, multiparous, nonbred lactating Holstein dairy cows (n = 18) had ovulation synchronized. On d 5 after ovulation, all cows had their corpus luteum regressed and were submitted to follicle (≥3 mm) aspiration 24 h later to induce emergence of a new follicular wave. Cows were then randomized to NoP4 (untreated) and NoP4+hCG (100 IU of hCG every 24 h for 4 d after follicle aspiration). Ultrasound evaluations and blood sample collections were performed every 12 h for 7 d after follicle aspiration. All cows were then treated with 200 μg of GnRH to induce ovulation. In replicate 2, cows (n = 16) were resubmitted to similar procedures (i.e., corpus luteum regression, follicle aspiration, randomization, ultrasound evaluations every 12 h, GnRH 7 d after aspiration). However, cows in replicate 2 received an intravaginal P4 device that had been previously used (～18 d). Only cows with single (n = 15) and double (n = 16) ovulations were used in the analysis. No significant differences were detected for frequency of double ovulation, follicle sizes, and FSH concentrations across replicates (NoP4 vs. LowP4 and NoP4+hCG vs. LowP4+hCG), so data were combined. Double ovulation was 40% for control cows with no hCG (CONT) and 62.5% with hCG (hCG). Double ovulation increased as the maximum size of F2 increased: <9.5 mm and 9.5–11.5 mm (7.7%) and ≥11.5 mm (94.1%). The hCG group had more cows with F2 > 11.5 (69%) than with 9.5 ≥ F2 ≤ 11.5 (25%) and F2 < 9.5 (6%). In agreement, F2 and F3 maximum size were larger in the hCG group, but FSH concentrations were lower after F1 > 8.5 mm compared with CONT. In contrast, FSH concentrations were greater before deviation (F1 closest value to 8.5 mm) in cows with double ovulations than in those with single ovulations, regardless of hCG treatment. In addition, time from aspiration to deviation was shorter in cows with double rather than single ovulation and in cows treated with hCG as a result of faster F1, F2, and F3 growth rates before diameter deviation. In conclusion, greater FSH and follicle growth before deviation seems to be a primary driver of greater frequency of double ovulation in lactating cows with low circulating P4. Moreover, the increase in follicle growth before deviation and in the maximum size of F2 during hCG treatment suggests that increased LH may also have a role in stimulating double ovulation.     

Polymorphism in the bovine growth hormone gene affects endocrine release in dairy calves

The objective was to test whether calves with the Leu/Leu genotype release more growth hormone (GH) than calves with Leu/Val and Val/Val genotypes. Danish Holstein (n = 286), Danish Red (n = 68), and Danish Jersey (n = 61) calves were genotyped for the Leu/Val polymorphism in the GH gene and assessed for GH release following inducement by the growth hormone releasing hormone (GHRH). Three GH traits were assessed for each calf: BASELINE, PEAK, and RATE. BASELINE and PEAK are the mean concentration of GH in blood sampled before and after GHRH inducement. RATE is the disappearance rate of GH in blood sampled after GHRH inducement. Danish Jersey calves with Leu/Leu genotype had a higher PEAK and RATE than calves with the Val/Val genotype, whereas the Leu/Val genotype had an intermediate response. The contribution of the Leu/Val polymorphism to the total genetic variation of the BASELINE, PEAK, and RATE traits was 5, 30, and 27%, respectively. By contrast, the amount of GH released by the Danish Holstein and Danish Red calves was not influenced by their GH genotype. Further studies involving calves with all three genotypes are required to further elucidate whether this polymorphism has a functional role or whether it works through a linked-gene effect specific to certain cattle breeds.     

Effect of dietary energy and somatotropin on components of the somatotropic axis in Holstein heifers

The somatotropic axis, consisting of growth hormone (GH), GH receptor (GHR), insulin-like growth factor (IGF)-I, IGF binding proteins (IGFBP), and IGF receptors, controls growth and mammary development in heifers. Manipulation of the axis with recombinant bovine somatotropin (rbST) improves heifer growth and reduces age at first calving. The effects of rbST are influenced by dietary energy through partially understood mechanisms. The objective was to characterize the somatotropic axis in Holstein heifers fed a diet for either low or high rate of gain and treated with or without rbST. Heifers (120 d of age) were assigned to one of 2 diets to gain either 0.8 kg/d (low, n = 18) or 1.2 kg/d (high, n = 20). Within each diet, half of the heifers (n = 9 for low and n = 10 for high) received daily rbST injections (25 microg/kg of body weight). Treatments and diets continued until slaughter (2 mo after puberty). Blood was collected 2x per week, and a frequent sampling window was performed 1 d before slaughter. Liver was collected at slaughter. Feeding a high diet or treating with rbST increased serum IGF-I and decreased serum IGFBP-2. The observed changes in serum IGF-I and IGFBP-2 were reflected in their respective liver mRNA amounts. Feeding a high diet decreased serum GH concentrations after rbST injection, but the stimulatory effect of rbST on serum IGF-I was nonetheless greater in high-diet heifers. The differential IGF-I response may be explained by greater GHR 1A in the liver of high-diet heifers. We conclude that a high-gain diet modifies the somatotropic axis in rbST-treated heifers by decreasing serum GH but increasing serum IGF-I after rbST treatment. Greater IGF-I (indicative of an increased GH response) may be a consequence of greater GHR 1A expression in the liver.     

Hormonal and lactational responses to growth hormone-releasing hormone treatment in lactating Japanese Black cows

Ten multiparous lactating Japanese Black cows (beef breed) were used to evaluate the effects of bovine growth hormone-releasing hormone (GHRH) analog on milk yield and profiles of plasma hormones and metabolites. The cows received 2 consecutive 21-d treatments (a daily s.c. injection of 3-mg GHRH analog or saline) in a 2 (group) x 2 (period) Latin square crossover design. The 5 cows in group A received GHRH analog during period 1 (from d 22 to 42 postpartum) and saline during period 2 (from d 57 to 77 postpartum), and those in group B received saline and GHRH analog during periods 1 and 2, respectively. Mean milk yield decreased in saline treated compared with that during the 1-wk period before treatment 7.4 and 19.1% during periods 1 (group B) and 2 (group A), respectively. Treatment with GHRH analog increased milk yield 17.4% (period 1, group A) and 6.3% (period 2, group B). Treatment with GHRH analog induced higher basal plasma concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin, and glucose compared with saline-treated cows. In glucose challenge, the GHRH analog-treated beef cows had greater insulin secretion than the saline-treated beef cows. In insulin challenge, however, there were no significant differences in the areas surrounded by hypothetical lines of basal glucose concentrations and glucose response curves between GHRH analog- and saline-treated cows. These results demonstrate that GHRH analog treatment facilitates endogenous GH secretion in lactating Japanese Black cows, leading to increases in milk yield and plasma concentrations of IGF-1, insulin, and glucose.     

烟碱对小鼠运动性疲劳的作用研究

为研究烟碱对小鼠负重游泳时间和抗疲劳相关理化指标的影响,选择SPF昆明种雄性小鼠随机分为4组,试验组每天分别皮下注射尼古丁酒石酸盐（生理盐水配制）0.1 mg/kg、0.5 mg/kg、1.0 mg/kg,对照组每天注射1.0 mg/kg生理盐水,在注射20 d后检测体重、负重游泳时间,以及血尿素氮、血乳酸、肝糖原含量。结果表明,0.5 mg/kg尼古丁酒石酸盐能显著增加小鼠游泳时间,降低血尿素氮和血乳酸浓度,而对肝糖原含量没有影响。小鼠游泳时间的增加可能是因为烟碱刺激小鼠激素的分泌而导致运动能力增强。     

大麦发芽过程中内源激素的变化

选用进口大麦Gairdner和国产大麦甘啤二号为原料,分析比较了发芽过程中赤霉素、生长素和脱落酸等内源激素含量的变化规律。研究结果表明,3种激素在两种大麦发芽过程中均呈现出随发芽时间上下波动的趋势,且两种大麦在发芽过程中各激素含量的变化规律基本一致。同时,赤霉素均有刺激并诱导其他两种内源激素的作用。