A releaser pheromone that attracts methyltestosterone- treated immature fish in the urine of ovulated female rainbow trout

SUMMARY: Behavioral experiments concerning a releaser pheromone in the urine of female rainbow trout were performed using immature fish administered orally with 17α-methyltestosterone (MT) during the non-spawning season. The urine was collected by catheter. The frequency of entries of test fish was recorded in each channel scented by test and control solutions in a Y-maze trough. The behavior of both MT-treated and control fish demonstrated that they could not discriminate the differences between distilled and environmental water as control solutions. There was also no difference between MT-treated and control fish when distilled and environmental water were introduced. The MT-treated immature fish were attracted to the channel scented by ovulated female urine. Neither coelomic fluid nor the immature female urine had any effect on the behavioral responses of MT-treated fish, while immature control fish had no preference for the urine of ovulated females. These results suggest in rainbow trout that ovulated female urine contains a releaser pheromone to attract mature males, and that androgens are involved in the sensory mechanisms detecting the releaser pheromone in fish.     

柞蚕肠液理化性质与饲料效率的相关性研究

对柞蚕肠液的理化性质与饲料效率的相关性进行研究的结果表明 :柞蚕肠液对促进蚕体抗病与消化吸收功能有着重要作用 ,平均每头蚕有肠液 1 76mL ,品种间开差为 0 78mL ,相对开差 5 7 80 % ,肠液量越多 ,饲料效率越高 ;柞蚕不同品种肠液pH平均值未发现明显差异 ,但强健好养饲料效率高的品种个体间开差小 ;柞蚕肠液缓冲力除与品种强健性有关外 ,还与品种的饲料效率呈正相关 ,在强健丰产与高饲料效率品种中 ,肠液恢复pH原值所需时间越短 ,饲料效率越高 ,电刺法取出肠液后 ,肠液恢复缓冲力所需时间是恢复其pH原值时间的 1 8倍多 ,同恢复肠液pH原值所需时间长短与品种强健性和饲料效率的关系完全一致。     

Effect of ruminal dosing of mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in Holstein steers fed a concentrate diet

This experiment was conducted to determine the effect of ruminal dosing of a mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in steers fed a concentrate diet at maintenance level. Animals were dosed three Rumen Faibu (RF) per head through the rumen fistulae (RF treatment) and not dosed (control) in a change‐over design. The organic cell wall content of the concentrate diet was 12.7% of dry matter. Daily time spent on rumination was very short in both treatments with 24 min in RF treatment and 15 min in control. The turnover rate of ruminal fluid in RF treatment was higher than that in control. There were no differences in ruminal pH and total volatile fatty acid concentration between RF treatment and control. Acetic and butyric acid concentrations were not different between the treatments. Propionic acid concentration tended to be higher in the animals on RF treatment than in control animals. The RF dosing in Holstein steers fed a low fiber diet did not affect the rumination time, but increased rumen digesta passage rate and ruminal propionic acid production.     

乳牛瘤胃挥发性脂肪酸的气相色谱分析

本文介绍了一种准确、可靠、简便、快速的乳牛瘤胃挥发性脂肪酸(VFA)的气相色谱分析方法。瘤胃液只经过一步前处理即可进样分析,从样品预处理到给出测定结果仅需15min,主要VFA的回收率可达97.86％～99.51％之间,变异系数在0.23％～1.19％之间。     

葡萄子油及原花青素研究与开发利用

综述了葡萄子油、葡萄子原花青素等天然产物的提取与保健作用的研究进展,原花青素的生物活性及药理研究的现状,葡萄子油成分分析方法和葡萄子,提取物中原花青素含量测定的方法;介绍了用超临界CO2萃取法制取高质量的葡萄子油和应用夹带剂提取葡萄子中的原花青素的方法。分析了葡萄子的综合开发的应用前景。     

Effect of cyclodextrin diallyl maleate on methane production, ruminal fermentation and microbes in vitro and in vivo

Effects of β‐cyclodextrin diallyl maleate (CD‐M) on methane production, ruminal fermentation and digestibility were studied both in vitro and in vivo. In in vitro study, diluted ruminal fluid (30 mL) was incubated anaerobically at 38°C for 6 and 24 h with or without CD‐M using hay plus concentrate (1.5:1) as a substrate. The CD‐M was added at different concentrations (0, 1.25, 2.5, 5.0 and 7.5 g/L). The pH of the medium and numbers of protozoa were not affected by the addition of CD‐M. Total volatile fatty acids were increased and ammonia‐N was decreased, molar proportion of acetate was decreased and propionate was increased (P < 0.05) by CD‐M. Methane was inhibited (P < 0.05) by 14–76%. The effect of CD‐M on methane production and ruminal fermentation was further investigated in vivo using four Holstein steers in a cross‐over design. The steers were fed Sudangrass hay and concentrate mixture (1.5:1) with or without CD‐M (2% of feed dry matter) as a supplement. Ruminal proportion of acetate tended to decrease and that of propionate was increased (P < 0.05) 2 h after CD‐M dosing. Total viable counts, cellulolytic, sulfate reducing, acetogenic bacteria and protozoa were unaffected while methanogenic bacteria were decreased (P < 0.05) by CD‐M. The plasma concentration of glucose was increased, whereas that of urea‐N was decreased (P < 0.05). Methane was inhibited (P < 0.05) from 36.4 to 30.1 L/kg dry matter intake by the addition of CD‐M. Apparent digestibilities of dry matter and neutral detergent fiber were not affected while that of crude protein was increased (P < 0.05) in the medicated steers. These data suggested that dietary supplementation of CD‐M decreased methane production and improved nutrient use.     

断奶前补饲不同直/支链淀粉比开食料对羔羊瘤胃上皮发育的影响

为了研究断奶前补饲不同直/支链淀粉比开食料对羔羊瘤胃上皮发育的影响,选取24只体况良好、胎次一致、体重相近的10日龄羔羊(湖羊),将其随机分为3组,在饲喂相同母乳的基础上,分别补饲以纯木薯(CS)、玉米(MS)和豌豆淀粉(PS)(直/支链淀粉比分别约为0.11,0.27和0.44)为唯一淀粉来源的开食料。试验期间,每天4:00-19:00将羔羊抱入补饲栏补饲不同直/支链淀粉比的开食料,并且在6:30, 10:30和15:30将羔羊抱回母羊舍哺乳1 h。羔羊自由饮水,单栏饲喂,自由采食燕麦干草。56日龄时屠宰采样,采集瘤胃组织样品制作石蜡切片进行瘤胃乳头形态测定,采集瘤胃上皮样品提取RNA测定相关基因表达。结果表明:CS组羔羊瘤胃乳头长度和表面积显著(P<0.001)高于MS和PS组,CS和MS组羔羊瘤胃乳头宽度显著(P=0.001)高于PS组。对瘤胃上皮各层厚度统计显示,CS和PS组羔羊瘤胃上皮角质层厚度显著(P=0.001)高于MS组;CS和MS组羔羊瘤胃上皮颗粒层厚度显著高于(P<0.001)PS组;CS组羔羊瘤胃上皮棘基层厚度和总厚度显著(P<0.001)高于MS和PS组。qRT-PCR结果显示:不同直/支链淀粉比开食料显著影响羔羊瘤胃上皮CDK2和CDK6的mRNA表达量(CS>MS>PS, P<0.001);CS组羔羊瘤胃上皮细胞cyclin A和CDK4的mRNA表达量显著(P<0.05)高于PS组,但与MS组无显著差异;CS组羔羊瘤胃上皮cyclin D1的mRNA表达量显著(P=0.012)低于PS组,但与MS组无显著差异。CS组羔羊瘤胃上皮类胰岛素生长因子-1(insulin like growth factor,IGF-1)的mRNA表达量显著(P<0.001)高于MS和PS组,CS和MS组羔羊瘤胃上皮IGF-1R的mRNA表达量显著(P=0.001)高于PS组。上述结果表明:较高支链淀粉比开食料与较高直链淀粉比开食料相比,在瘤胃中较易降解生成挥发性脂肪酸,促进瘤胃上皮IGF-1及细胞周期蛋白mRNA的表达,进而有利于断奶前羔羊瘤胃上皮的发育。研究结果对制订羔羊营养方案具有重要指导意义。     

Effect of oak (Quercus persica) acorn level on apparent digestibility,ruminal fermentation,nitrogen balance and urinary purine derivatives in pregnant goats

The aim of this experiment was to investigate the effect of dietary oak (Quercus persica) acorn (OA) level on dry matter intake (DMI), apparent nutrient digestibility, nitrogen (N) utilization, ruminal fermentation, protozoa population and urinary purine derivatives (PD) during the last 60 days of goat pregnancy. Twenty‐four multiparous pregnant goats (41.7 ± 2.3 kg BW) were assigned to one of three experimental diets consisted of control diet (C, without OA) and diets containing 20 (OA₂₀) or 40 g/100 g of OA (OA₄₀) on a DM basis in a completely randomized block design. Goats fed OA₄₀ had lower DMI (p < .01), DM (p < .01), OM (p < .01) and NDF (p < .05) digestibility, ruminal NH₃‐N concentration (p < .01), N intake (p < .01) and N retention (p < .01). Crude protein digestibility and ruminal acetate and total volatile fatty acid (VFA) concentration were lower in animals fed OA‐contained diets (p < .01), whereas ruminal propionate concentration was higher in goats fed the C diet (p < .01). Animals fed OA₄₀ had higher faecal N excretion and lower urinary N excretion (p < .01). Urinary PD was lower in goats fed diets containing OA in relation to those fed the C diet (p < .01). Total protozoa population decreased linearly with increasing OA level in the diet (p < .05). These results suggest that feeding OA, especially high level, has negative impacts on DMI, nutrient digestibility, VFA concentration, N retention and urinary PD excretion that may have adverse effects on metabolism and performance of pregnant goats.     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.