不同养殖密度瓦氏黄颡鱼肌肉营养成分分析与评价

目的分析评价不同密度养殖瓦氏黄颡鱼(Pelteobagrus vachelli)肌肉的营养品质。方法采用国家标准的方法,对瓦氏黄颡鱼肌肉的营养成分进行分析。结果高密度(40、60、80尾/m~3)养殖瓦氏黄颡鱼肌肉的粗蛋白含量显著高于低密度组(20尾/m~3),而粗脂肪含量、能值和E/P值却相反。60尾/m3养殖瓦氏黄颡鱼肌肉的呈味氨基酸、必需氨基酸、氨基酸总量、EAAI值及E/T、E/N值均高于其他组。60尾/m~3瓦氏黄颡鱼肌肉的顺式亚油酸相对含量、α-亚麻酸相对含量、EPA+DHA相对含量、单不饱和脂肪酸、多不饱和脂肪酸及必需脂肪酸总量均高于其他组。结论瓦氏黄颡鱼养殖密度在60尾/m~3时肌肉的必需氨基酸构成比例均衡,不饱和脂肪酸含量丰富,营养价值最高。本研究为瓦氏黄颡鱼高密度集约化养殖提供了参考依据。     

膨化饲料中玉米蛋白粉对黄颡鱼生长的影响

为了研究饲料中玉米蛋白粉对黄颡鱼生长性能、部分生理功能的影响,以初均重(13.82±1.06)g的黄颡鱼为试验对象,以使用挤压膨化日粮在等氮、等能、等磷条件下,将饲料中玉米蛋白粉用量设置0%、6%、10%、14%,以及叶黄素添加对照组共5个试验组,每组3个平行。在池塘网箱中饲养58 d,结果显示,不同饲料组黄颡鱼的成活率、饲料系数、特定生长率、增重率、蛋白效率差异不显著(P0.05);各组别黄颡鱼的脏体长、肝体比、肥满度和鱼体营养组成等差异不显著(P0.05);对黄颡鱼的血脂含量、非特异免疫力、肝胰脏功能等无显著性影响(P0.05),而对血糖含量则产生显著性影响(P0.05)。在黄颡鱼挤压膨化饲料中可以使用6%的玉米蛋白粉,能够维持黄颡鱼的正常生产性能和正常生理功能。     

洞庭湖黄颡鱼肌肉营养成分及品质特性分析

采用理化分析方法分析了黄颡鱼肌肉中的营养成分、系水力和质构特性。结果表明,黄颡鱼的含肉率为 ( 68.57±1.38) %,肌肉 (鲜样 ) 中水分、 粗蛋白、 粗脂肪和粗灰分的含量分别为 (76.84±2.11)%、(15.52±0.64)%、(5.87±0.43)%和(1.19±0.12)% 。肌肉贮存损失率(1.35±0.29)%、冷冻渗出率(2.87±0.94)、蒸煮失重率(15.12±1.56)%。质构特性中硬度(2946.38±571.84)、弹性(0.67±0.06)、凝聚性(0.46±0.05)、胶黏性(1043.54±313.89)、咀嚼性(457.63±193.46)、回复性(0.30±0.07)。肌肉中含钙(586.41mg/Kg)、锌(14.73mg/Kg)、铁(21.40mg/Kg)、铜(81.59mg/Kg),有合理的Cu、Zn、Fe比值;含有 18种氨基酸,干基中氨基酸的总量(78.40±0.74) %, 其中人体必需氨基酸8 种含量 ( 34.03 ±0.26) %,占总氨基酸总量的 43.41%;4种鲜味氨基酸含量 (30.7±0.39) % ,占氨基酸总量的 39.16%,必需氨基酸指数为 69.02。EPA与 DHA在脂肪酸中的含量较高,分别为 (2.18±0.11) %、 ( 3.87±0.18) %。表明黄颡鱼具有较高的食用价值与保健作用。     

温度对黄颡鱼无水保活工艺的影响

以黄颡鱼为研究对象,研究其在0、3、6℃3个不同温度组无水保活过程中存活率、O_2消耗量、CO_2含量、肌糖原含量、腺嘌呤核苷三磷酸(ATP)含量和乳酸含量等指标的变化,探索温度对黄颡鱼无水保活因素的影响。结果表明:黄颡鱼成活率在保活过程中呈下降趋势,保活24 h时,0℃组成活率仍为100%,而6℃组已下降至85.71%。O_2消耗量随保活时间的延长逐渐降低,CO2含量随保活时间的延长逐渐上升。肌糖原随保活时间的延长逐渐降低,0℃组下降速度最快,6℃组下降速度最慢。ATP和乳酸含量的变化趋势一致,随保活时间的延长先升高后降低,在保活12 h之前ATP和乳酸含量是逐渐增加的,6℃组ATP和乳酸含量上升速率最快,0℃组ATP和乳酸含量的上升速率最慢,且在相同的保活时间下两组有明显差异(P0.05),12 h后ATP和乳酸含量逐渐下降。综上所述,黄颡鱼最适无水保活温度为0℃。     

黄颡鱼和大鳍鱯肌肉及鱼卵中脂肪酸组成的比较

采用GC测定了黄颡鱼和大鳍鱯的脂肪酸组成。结果表明:在两种鱼的肌肉和鱼卵中含有22种脂肪酸。在黄颡鱼肌肉中饱和脂肪酸占34.90%;不饱和脂肪酸中,单不饱和脂肪酸占51.37%,多不饱和脂肪酸占13.74%。在黄颡鱼卵中,饱和脂肪酸占26.76%,单不饱和脂肪酸占49.51%,多不饱和脂肪酸占23.73%。从大鳍鱯来看,肌肉中饱和脂肪酸占26.97%,单不饱和脂肪酸占48.81%,多不饱和脂肪酸占24.23%;鱼卵中饱和脂肪酸占30.75%,单不饱和脂肪酸占44.08%,多不饱和脂肪酸占25.17%。研究揭示了黄颡鱼和大鳍鱯的肌肉脂质中以不饱和脂肪酸为主,是理想的食品。两种鱼的鱼卵还含有较高的花生四烯酸（C20:4n-6,ARA）、廿碳五烯酸（C20:5n-3,EPA）和廿二碳六烯酸（C22:6n-3,DHA）的比例,鱼卵的食用、加工值得进一步研究和开发。      

传统养殖与组合湿地-池塘循环水养殖黄颡鱼的品质比较

为比较传统养殖与组合湿地-池塘循环水养殖黄颡鱼（Pelteobagrus fulvidraco）的品质差异,该研究对养殖池塘水质进行评价的同时,利用超高效液相色谱、气相色谱-质谱联用等技术分析了组合湿地-池塘循环水及传统池塘养殖黄颡鱼的表观及质地品质、营养品质、风味品质。结果表明,组合湿地-池塘循环水池塘水质污染程度较低、水体富营养化程度减缓且其中养殖的黄颡鱼肌肉空壳率、亮度及白度值显著高于传统组,肌肉的蒸煮损失率显著降低。湿地组黄颡鱼必需氨基酸/总氨基酸为40.40%,必需氨基酸/非必需氨基酸为78.67%,肌肉氨基酸组成更符合FAO/WTO推荐的理想蛋白模式。湿地组黄颡鱼不饱和脂肪酸、Omega-3脂肪酸及Omega-6脂肪酸含量分别为传统组的3.78倍、2.64倍以及3.25倍。湿地组黄颡鱼中呈油脂味等异味的挥发性气味物质含量下降,且呈苦味及酸味的氨基酸总占比下降,呈鲜味及甜味的氨基酸总占比上升,呈鲜味的IMP含量为传统组的3.16倍,呈苦味的Hx R及Hx含量较传统组下降了17.00%及17.57%。综上,组合湿地-池塘循环水养殖黄颡鱼可食用部分占比更高,肉质更为白亮,肌肉营养...     

饲料色素对黄颡鱼生长和生理机能的影响

将加丽素红、金黄素及金菊黄3种外援色素和饲料原料色素物质配入黄颡鱼饲料中,进行为期8周的养殖试验.结果表明:各试验组间黄颡鱼的特定生长率无显著差异(P>0.05).加丽素红组、金黄素组和玉米蛋白粉组饲料蛋白质效率均分别比对照组显著降低26.2%、25.1%和24.9%,金菊黄组降低13.3%.对照组饵料系数最低,显著低于金黄素组和玉米蛋白粉组.金黄素和金菊黄的添加使得黄颡鱼的成活率达到90.2%,高于其它各组.饲料色素的添加对黄颡鱼的内脏比、肝体比无显著影响(P>0.05),但对鱼体肝胰脏中脂肪含量有一定的影响,金黄素组鱼体肝胰脏中脂肪比对照组显著下降了18.2%.饲料色素的添加对黄颡鱼血液中血红蛋白的含量、血清中SOD酶、溶茵酶活力和肝胰脏GPT活力均无显著影响(P>0.05).     

山苍子精油/壳聚糖涂膜保鲜对黄颡鱼贮藏品质的影响

为研究山苍子精油(Litsea cubeba oil, LCO)与壳聚糖(Chitosan, CS)协同处理对黄颡鱼贮藏品质的影响,以黄颡鱼为实验材料,采用对照组、壳聚糖涂膜、不同浓度山苍子精油/壳聚糖组复合涂膜(0.2%、0.4%、0.6%)处理。4℃下贮藏保鲜13 d,测定其肌肉p H值、挥发性盐基氮(Total volatile basic nitrogen, TVB-N)值、菌落数、硫代巴比妥酸(Thiobarbituric acid, TBA)值、质构与感官评价等指标变化。结果显示：经CS+LCO处理,可有效延缓pH值、TBA值、TVB-N值及菌落总数的上升速度。贮藏至第9天时,pH值、TBA值、TVB-N值及菌落总数分别比对照组低3.3%、37.7%、38.17%、11.74%。同时,CS+LCO处理组肌肉的硬度、弹性、咀嚼度、回复性等质构指标下降减缓,感官评分高于同期其他样品。因此可见,LCO/CS涂膜能较好保持黄颡鱼的贮藏品质,延长其货架期,其中以CS+0.6%LCO处理效果最佳。     

黄颡鱼无水保活技术研究

研究了黄颡鱼在生态冰温区的无水保活运输技术、相关的影响因子及鱼体肌肉和血液中生化指标的变化.结果表明:黄颡鱼的生态冰温区为-1～4℃,黄颡鱼暂养2d后,在低温(2℃)纯氧状态下可保活24h,且可在常温水中(20℃)完全复苏;在保活过程中,肌肉中糖原含量、pH下降、乳酸含量上升,血液中肌酐、血糖、乳酸含量显著上升,白蛋白显著下降,尿酸显著上升;保活前后,除肌酐、血糖、乳酸外其他各项指标没有显著变化.     

不同烹饪方式对黄颡鱼肉品质特性的影响

为探究不同烹饪方式和程度下黄颡鱼品质特性的差异,试验以生鱼肉作为对照,研究了水煮、油炸和微波3种烹饪方式对黄颡鱼基础营养物质、质构及挥发性风味化合物的影响。结果表明,黄颡鱼品质特性在不同烹饪方式下有显著差异。水煮处理对营养物质的影响最小;油炸和微波处理均能不同程度地提高灰分、蛋白质和脂肪的百分含量。3种烹饪方式均使鱼肉的硬度、粘附性、弹性和咀嚼性上升,胶黏性下降,其中水煮处理的鱼肉硬度和咀嚼性较低。水煮、油炸和微波处理的鱼肉中分别检出挥发性成分27,32,30种,微波处理主要挥发性成分的醛类和醇类总量达73.71%。综合来看,3种烹饪方式中微波处理的黄颡鱼肉品质最佳。     

Prepartum stocking density: Effects on metabolic,health, reproductive,and productive responses

The objectives of the current experiment were to determine the effects of 2 prepartum stocking densities on milk yield, concentration of metabolites during the peripartum period, and health and reproductive parameters of dairy cows. Jersey cows enrolled in the experiment at 254 ± 3 d of gestation were balanced for parity (nulliparous vs. parous) and previous lactation projected 305-d mature equivalent milk yield (parous) and assigned to 1 of 2 treatments: 80% headlock stocking density (80SD; 38 animals/48 headlocks) and 100% headlock stocking density (100SD; 48 animals/48 headlocks). The number of experimental units was 8 (4 replicates and 2 pens/treatment per replicate). In total, 154 nulliparous and 184 parous animals were enrolled in the 80SD treatment and 186 nulliparous and 232 parous animals were enrolled in the 100SD treatment. At the start of each replicate, treatments were switched within pen. Cows were milked thrice daily and monthly milk yield, fat and protein content, and somatic cell count data were recorded up to 155 d postpartum. Plasma nonesterified fatty acid concentration was measured weekly, from −18 ± 3 to 17 ± 3 d relative to calving, and plasma β-hydroxybutyrate was measured weekly, from 1 ± 2 to 17 ± 3 d relative to calving. Cows were examined 1, 4 ± 1, 7 ± 1, 10 ± 1, and 13 ± 1 d relative to calving for diagnosis of uterine diseases. Blood was sampled for determination of progesterone concentration and resumption of ovarian cycles 35 ± 3 and 45 ± 3 d relative to calving. Average headlock (74.1 ± 0.4 vs. 94.5 ± 0.3%) and stall (80.8 ± 0.4 vs. 103.1 ± 0.4%) stocking density was lower for the 80SD treatment compared with the 100SD treatment. Treatment did not affect incidence of retained fetal membranes (80SD = 5.1, 100SD = 7.8%), metritis (80SD = 21.2, 100SD = 16.7%), acute metritis (80SD = 9.9, 100SD = 9.4%), and vaginal purulent discharge (80SD = 5.8, 100SD = 7.9%). Concentrations of nonesterified fatty acids (80SD = 251.5 ± 6.1, 100SD = 245.9 ± 5.6 μmol/L) and β-hydroxybutyrate (80SD = 508.2 ± 14.3, 100SD = 490.9 ± 13.6 μmol/L) were not different between treatments. Treatment had no effect on percentage of cows removed from the herd on the first 60 d postpartum (80SD = 6.1, 100SD = 5.1%) and on rate of removal from the herd up to 305 d postpartum 80SD = referent, 100SD [adjusted hazard ratio (95% confidence interval)] = 1.02 (0.75, 1.38). Percentages of cows pregnant to first (80SD = 41.9, 100SD = 48.4%) and second (80SD = 49.3, 100SD = 42.0%) postpartum AI were not different between treatments. Finally, treatment did not affect energy-corrected milk yield up to 155 d postpartum (80SD = 33.8 ± 0.5, 100SD = 33.4 ± 0.5 kg/d). In herds with weekly or twice weekly movement of new cows to the prepartum pen and separate housing of nulliparous and parous animals, a target stocking density of 100% of headlocks on the day of movement is not expected to affect health, metabolic, reproductive, and productive parameters.     

Short communication: effect of stocking density on indices of cow comfort

The objective of this study was to evaluate the effects of increasing stocking density on indices of cow comfort measured over a 24-h period, during peak lying time (0000 to 0400 h), and 1 h after the afternoon milking. Holstein cows (n = 136) were assigned to 1 of 4 pens, and stocking densities of 100, 113, 131, and 142% were applied in a 4 × 4 Latin square. Video data were recorded continuously for 2 d after 5 d of acclimation to stocking density and analyzed with 10-min scan samples for the percentage of cows lying in a stall, standing in a stall, standing in the alley, and eating at the manger. Percentage of cows standing idly in the alley increased as stocking density increased above 113% (10.9, 12.0, 14.4, and 16.5% for 100, 113, 131, and 142% stocking density, respectively). Cow comfort index (CCI; cows lying down/cows contacting stalls) and stall standing index (SSI; cows standing in stall/cows contacting stalls) differed little as stocking density increased, but stall use index (SUI; cows lying in stall/cows in pen not eating) decreased beyond 113% stocking density (70.1, 70.2, 68.6, and 66.3 for 100, 113, 131, and 142% stocking density, respectively). During peak lying time, SUI decreased with increasing (80.3, 79.5, 74.8, and 69.6 for 100, 113, 131, and 142% stocking density, respectively) stocking density above 113%, whereas CCI and SSI showed little response. None of the indices varied by stocking density when they were assessed at 1 h after milking. These results suggest that more than 1 index of cow comfort may be needed at higher stocking densities to assess both stall usage and cows standing idly in an alley. At higher stocking densities, SUI was reduced, because it reflected not only stall usage but the number of cows standing idly in an alley and not actively feeding and unable to access a stall. The CCI and SSI appear to assess actual stall usage (% cows lying or standing) across the range of stocking densities evaluated in this study.     

Effects of prepartum stocking density and a blind on physiological biomarkers,health, and hygiene of transition Holstein dairy cows

Many dairy cows succumb to disease after calving. Disease risk may be affected by the cows' social environment and ability to perform maternal behaviors. In nature, cattle isolate from others and find seclusion to give birth; these behaviors may be limited in indoor group pens and could potentially affect the cows' ability to cope. The aim was to determine whether stocking density and a physical blind in prepartum bedded-pack group pens affected physiological biomarkers, disease risk, and hygiene of peripartum dairy cows. A randomized complete block designed with a 2 × 2 factorial arrangement of treatments was used. Approximately 3 wk before calving, 374 cows (primiparous = 127; multiparous = 247) were assigned randomly to 1 of 4 treatment pens with the following 2 factors: (1) high versus low stocking density (7.7 to 12.9 m² vs. 15.4 to 25.8 m² lying space per cow), and (2) presence or absence of a blind. The blind was created using plastic road barriers and plywood, a steel gate, and shade cloth. After calving, cows were moved into a freestall pen and milked 3 times per day. Blood was sampled on the day of enrollment (baseline; ?24 d) and approximately ?14, ?7, 3, 7, 10, and 14 d relative to calving, to measure inflammatory (haptoglobin) and metabolic (nonesterified fatty acids and β-hydroxybutyrate) biomarkers. β-Hydroxybutyrate (≥1.2 mmol/L) was used to diagnose subclinical ketosis. Vaginal discharge was scored 3, 7, 10, and 14 d after calving, to diagnose metritis (none, mild, or severe). Hygiene was scored on ?24, ?14, and ?7 d before calving. Before calving, haptoglobin was lower in pens with a blind. After calving, cows in pens with low stocking density before calving tended to be at greater odds of being diagnosed with metritis. Cows were more likely to have poorer hygiene scores in high stocking density pens. No treatment effects were detected for pre- and postpartum nonesterified fatty acids, β-hydroxybutyrate, postpartum haptoglobin, or subclinical ketosis. Results suggest that the provision of a blind and lower stocking density may be beneficial for reducing inflammation before calving. However, low prepartum stocking density might increase the odds of metritis after calving. Although the reason for this paradox is unclear, the effects of prepartum stocking density may require further exploration.     

氨基酸溶液电渗析脱盐过程的研究

测定了不同浓度和流速下的盐水和氨基酸盐溶液的极限电流密度,分析了浓度、流速、氨基酸含量等因素对电渗析极限电流密度的影响,提出了描述电渗析特性的数学模型。初步研究了应用电渗析对氨基酸盐溶液进行处理时,流速和电压对脱盐率和氨基酸回收率的影响,用较低的流速在接近极限电流密度的条件下操作能达到最好的分离效果。     

苏尼特羊肉氨基酸组成及与其他羊肉的对比分析

目的 分析苏尼特羊肉氨基酸组成以及与其他羊肉氨基酸组成进行对比分析。方法 以锡林郭勒放牧型苏尼特羊肉、乌珠穆沁羊肉、察哈尔羊肉以及两个区域舍饲型小尾寒羊肉为研究对象,通过氨基酸自动分析仪测定不同样品中氨基酸组成和含量,并进行比较分析。结果 苏尼特羊肉的水解氨基酸和游离氨基酸含量显著高于乌珠穆沁羊肉和察哈尔羊肉(P<0.05);苏尼特羊肉的水解氨基酸含量与舍饲型小尾寒羊肉无显著差异(P>0.05),但是其游离氨基酸含量显著高于舍饲型小尾寒羊肉。5种羊肉必需氨基酸/非必需氨基酸均高于60%,必需氨基酸/总氨基酸在40%左右,符合联合国粮农组织/世界卫生组织(UnitedNationsFood Agriculture Organization/World Health Organization, FAO/WHO)人体理想蛋白质模式。结论 苏尼特羊肉水解氨基酸和游离氨基酸组成丰富,含量较高,具有较高营养价值和食用品质。     

广西海鸭蛋中氨基酸的含量及组成分析

目的 研究广西区内海鸭蛋氨基酸含量及其组成分析广西海鸭蛋的品质。方法 采用盐酸水解法处理18组海鸭蛋样品,通过日立氨基酸自动分析仪测定16种氨基酸总含量,分析海鸭蛋各氨基酸的含量及其组成。结果 18份海鸭蛋样品中氨基酸的测定结果表明,广西海鸭蛋中氨基酸总量在11.99 g/100 g~13.79 g/100 g范围,各氨基酸占氨基酸总量的比值相近,其中谷氨酸的含量最高, 约占氨基酸总量的13%, 组氨酸含量最低,约占氨基酸总量的2%,其他氨基酸的含量均在3%~9%的范围内。结论 广西海鸭蛋氨基酸总含量有差异,但氨基酸组成较稳定,各氨基酸占氨基酸总量的比值相近,谷氨酸的含量最高,组氨酸含量最低。人体必需氨基酸占氨基酸总量的百分比（E/T）为47.25%,人体必需氨基酸含量与9种非必须氨基酸含量的比值（E/N ）为0.89,符合1973年FAO/WHO提出的理想模式,说明海鸭蛋中氨基酸都属于优质蛋白质,具有很好的营养价值。     

四大名醋的游离氨基酸组成成分分析

目的检测四大名醋中的游离氨基酸,探讨各游离氨基酸对食醋滋味的贡献度,为食醋的质量控制及滋味品质的提高提供基础。方法先用磺基水杨酸溶液对食醋样品进行前处理,再利用30+氨基酸自动分析仪确定游离氨基酸含量。通过计算味道强度值(TAV)确定各游离氨基酸对食醋滋味的贡献率。结果保宁醋氨基酸含量最多为3438.55 mg/100 mL,红曲醋3年陈酿中氨基酸含量最少为737.55 mg/100 mL。保宁醋、镇江香醋、山西老陈醋中对滋味有贡献的氨基酸个数依次为11、8、5。不同酿造年份(3年、5年、8年)的红曲醋中对滋味有贡献的氨基酸个数依次为3、4、4。结论利用氨基酸自动分析仪可确定食醋中游离氨基酸的含量,而味道强度值的引入可计算各游离氨基酸对食醋滋味的贡献率。     

竹节人参中氨基酸含量及组成分析

以竹节人参根为原料,采用氨基酸自动分析仪对样品各种氨基酸的含量进行检测,并对其组成进行比较与分析：结果表明,竹节人参中总氨基酸含量较高,各种人体必需氮基酸种类齐全,且凡比例均衡。在各种人体必需氨基酸中,第一限制氨基酸为蛋氨酸＋胱氨酸。     

Effects of glucagon infusions on protein and amino acid composition of milk from dairy cows

Changing the composition of milk proteins and AA affects the nutritional and physical properties of dairy products. Intravenous infusions of glucagon decreases milk protein production and concentration by promoting the use of gluconeogenic blood AA for hepatic glucose synthesis. Little is known about how the diversion of AA to gluconeogenesis affects the composition of milk proteins and AA. The objective was to quantify changes in composition of milk protein and AA in response to i.v. glucagon infusions. Three separate experiments were used: 1) 8 Holstein cows were fed ad libitum and infused with glucagon at 10 mg/d for 14 d, 2) 7 Holstein cows were feed restricted and infused with glucagon at 10 mg/d for 14 d, and 3) 4 Brown Swiss cows were infused with glucagon at 5 and 10 mg/d for 2 d each. Milk and milk component yields and milk protein and amino acid composition of samples, collected with blood samples at the first and last day of the glucagon infusion period, were compared with those collected 1 d before and after the glucagon infusion period. Glucagon infusions decreased milk protein production and concentration in each experiment by at least 0.2 ± 0.05 kg/d and 4 ± 0.4 g/L, respectively. The decrease was accompanied by changes in milk protein composition, the most consistent being an increase in κ-casein (1.68 ± 0.27%). Overall, glucagon infusions resulted in higher proportions of κ-casein and α_S2-casein (1.34 ± 0.51%) and smaller proportions of α_S1-casein (−3.83 ± 1.75%) and α-lactalbumin (−0.91 ± 0.32%). Glucagon had little impact on milk AA composition except an increase in glycine (0.26 ± 0.11%). The results suggest that milk protein synthesis is regulated by many factors including AA and glucose availability.