饲粮精料水平和蛋氨酸铬添加剂量对舍饲滩羊生长性能、屠宰性能、肉品质和脂肪沉积的影响

本试验旨在探究饲粮精料水平和蛋氨酸铬(Cr-Met)添加剂量对舍饲滩羊生长性能、屠宰性能、肉品质和脂肪沉积的影响。采用2×3双因素试验设计,2个因素分别为饲粮精料水平和Cr-Met添加剂量,其中饲粮精料水平分别设为35%(低精料饲粮,饲粮精粗比为35∶65)和55%(高精料饲粮,饲粮精粗比为55∶45),Cr-Met添加剂量分别设为0、0.75和1.50 g/(d·只)。将60只雄性滩羊羔羊[平均体重为(21±1)kg]随机分配到6个试验组,每组10只。试验期为80 d,其中预试期15 d,正试期65 d。结果显示:1)与低精料饲粮组相比,高精料饲粮组滩羊的平均日增重、屠宰率、背膘厚度、肌内脂肪含量和后腿肉比重显著增加(P<0.05),但料重比与肌肉蒸煮损失、剪切力、pH、亮度(L*)值、红度(a*)值和黄度(b*)值则显著降低(P<0.05)。2)低精料饲粮组滩羊背膘厚度、皮下脂肪厚度、肌内脂肪含量和后腿肉比重随Cr-Met添加剂量的增加而线性降低(P<0.05),但肌肉pH则线性升高(P<0.05)。3)高精料饲粮组滩羊肋肉比重、腰肉比重以及肌肉剪切力和pH随Cr-Met添加剂量的增加而线性升高(P<0.05),而肌内脂肪含量和肌肉a*值则线性降低(P<0.05)。综合本试验测定指标,建议在滩羊养殖中选择精粗比为55∶45的高精料饲粮,Cr-Met的适宜添加剂量为1.50 g/(d·只),且不建议在精粗比为35∶65的低精料饲粮中添加Cr-Met。     

保鲜处理对冷鲜鲟鱼肉特征性风味成分的影响

为明晰保鲜处理对冷鲜鲟鱼肉冷藏期间的特征性风味物质的影响。本实验利用固相微萃取—气相色谱—质谱联用(SPME-GC-MS)结合电子鼻和电子舌技术，对经微酸性氧化电解水和ε-聚赖氨酸两步法保鲜处理的冷鲜鲟鱼肉在冷藏期间的挥发性成分和滋味成分进行分析。电子鼻能够对挥发性成分从整体上进行分析，贮藏后期保鲜处理组和对照组的鲟鱼肉挥发性气味的数据集无重叠区域，差异明显。利用SPME-GC-MS定性鉴定出46种挥发性物质，主要包括醛类、酮类、烃类和醇类等物质，其中己醛、庚醛、苯甲醛、辛醛、壬醛、癸醛和2,5-辛二酮、苯乙酮、3,5-辛二烯-2-酮为保鲜处理组的主要挥发性物质，保鲜处理延缓了冷鲜鲟鱼肉腥味的产生以及鱼肉香味的下降。电子舌检测冷藏过程中鲟鱼肉的滋味物质时发现，保鲜处理组苦味、涩味、咸味均低于对照组，两组样品贮藏6 d后，在苦味、涩味、咸味、鲜味方面均呈显著差异。保鲜处理起到了减缓冷藏期间冷鲜鲟鱼肉风味物质下降的作用，为保鲜处理在冷鲜鲟鱼肉中的应用提供了一定的理论基础。     

引进肉用绵羊品种的杂交利用研究进展

文章综述了从国外引进优良肉用绵羊品种对国内不同地方绵羊品种杂交改良方面的研究应用情况,重点介绍了萨福克羊、杜泊羊、无角陶赛特羊、美利奴羊、特克塞尔羊等优良绵羊品种与我国不同地方绵羊品种杂交,其杂交后代在生长发育性能、产肉性能、胴体品质等方面的表现,旨在总结中国肉用绵羊的杂交改良工作,为推动中国肉用绵羊杂交改良,提高地方绵羊的生长性能和肉用性能,扩大我国肉羊的生产规模,促进我国畜牧业的健康发展和动物性肉食结构平衡提供借鉴。     

电子鼻技术在肉与肉制品检测中的研究进展和应用展望

电子鼻因具备操作简单、能够快速、无损检测的特点，满足人们对肉与肉制品安全指标高效和高精确度检测提出了更高的要求。本文阐述了电子鼻技术的检测原理和其在硬件和软件系统方面的发展；从肉与肉制品的新鲜度检测、掺假检测、风味评价、病原微生物污染检测四个方向，对近年来电子鼻技术在肉与肉制品检测的应用研究进展进行了分析，突出了电子鼻技术应用的可行性和先进性；指出电子鼻技术在肉与肉制品检测中面临的检测效果参差不齐，电子鼻仪器体积大、价格高昂，模型通用性和普及性不够等不足。最后，本文从硬件系统和软件系统两方面，对未来电子鼻技术的发展及其应用前景进行了展望，包括硬件系统方面提高电子鼻传感器阵列电极膜材料的性能，增强电子鼻耐用性和识别气味的灵敏度；软件系统方面不断探索引入新的模式识别算法，使电子鼻技术实现对气味更快、更准确的识别分析。     

Seasonal Changes in Quality and Fatty Acid Composition of Black Mussel (Mytilus galloprovincialis)

The study was designed to assess the seasonal variations in the quality and lipid profile of mussel meat (Mytilus galloprovincialis) harvested along the Bulgarian coast of the Black Sea. The trial period lasted from June to October, and the sampling was carried out in the area of Varna Bay. Technological quality of the mussels was determined by measuring the water holding capacity (WHC) and cooking and roasting losses. Proximate composition, total aerobic plate count, and fatty acid analysis were carried out. Technological parameters and nutritional quality of the mussel meat were strongly affected by the season. During the summer, the mussels had higher mass, meat content, and meat yield (p < 0.001) compared to the early autumn, which corresponds to the lowest protein content during this season. Lipid profile showed seasonal variations in both individual and total fatty acid amounts (p < 0.001). Saturated fatty acids (SFA) had the highest content in summer, while monounsaturated fatty acids (MUFA) decreased gradually until the autumn. The content of polyunsaturated fatty acids (PUFA) reached its peak in October, contributing to the most favorable values of the nutritional indices of lipids in the early autumn.     

我国居民肉类消费特征及趋势判断——基于双对数线性支出模型和LA/AIDS模型

为分析我国城乡居民肉类消费水平及其结构特征,判断居民肉类消费的未来趋势,基于FAO和统计年鉴等相关统计数据,运用双对数线性支出模型和LA/AIDS模型(Linear approximated/Almost ideal deal demand system模型),测算我国及城乡居民肉类消费需求的价格弹性和收入弹性。结果显示我国居民肉类消费量不断增加,且城乡居民肉类消费差距逐步缩小。居民对牛羊肉需求的收入弹性最大,禽肉次之,猪肉最小。其中,农村居民对各项肉类消费需求的收入弹性均显著高于城镇。我国居民的牛羊肉需求对自身价格及其他肉类价格变动较敏感,猪肉需求对自身价格与其他肉类价格变动敏感度较低。由此推断,未来我国居民对牛羊肉消费将呈波动增长态势,而对猪肉的消费呈缓慢增长,但消费量趋于稳定。     

生鲜肉类食品供应链碳排放测算及动态优化研究

以生鲜肉类食品供应链作为研究对象,基于生命周期理论界定生鲜肉类食品供应链碳排放的系统边界,并结合系统动力学方法建立生鲜肉类食品供应链的系统动力学模型,探讨肉类食品供应链的碳排放问题。研究结果表明:1)1t生鲜肉在其生命周期内产生的碳排放为166.97kg,其中生产、运输、仓储和销售环节中碳排放分别占总供应链的28.68%、52.37%、8.90%和10.04%,运输环节对全供应链的碳排放贡献率最高。2)动态优化研究发现,运输环节改变长途运输方式、生产环节废弃物回收利用及优化生产设备效率、销售环节降低设备功率取得的碳排放优化效果最佳,在2018年供应链碳排放分别降低了41.10%、4.70%、1.61%和1.25%。3)目前优化运输能源结构、开发可再生的清洁能源已成为大势所趋,且模拟结果表明,运输中燃烧生物柴油可降低供应链碳排放的13.10%,减排效果较为显著。4)在生鲜肉预冷过程中降低制冷系统能耗、在冷藏及销售过程中提高设备空间利用率可分别使供应链年碳排放降低2 100、1 600t,虽实施效果较小,但该措施便于操作,是降低供应链碳排放的有效途径。     

Effect of high inclusion of rendered animal by‐product ingredients on growth,digestibility and economic performances in climbing perch Anabas testudineus

A 70‐day growth trail was conducted to investigate the effects of inclusion of high levels of meat and bone meal (MBM) and protein concentrate (PC) on growth, digestibility and economic performances of climbing perch, Anabas testudineus. Four isonitrogenous diets were formulated by lowering the level of dietary fishmeal protein at 0 (D₁, control), 70 (D₂), 85 (D₃) and 100% (D₄) with a mixture of MBM and PC protein (1:1). Triplicate groups of 300 fish (mean weight of 0.80 g) stocked in each 40 m² pond and fed the respective test diets. A digestibility trial was conducted after the growth trial in indoor glass aquarium. The result showed that growth parameters were significantly decreased (P < 0.05) with fishmeal replacement levels. However, significant differences were not found in feed conversion ratio and survival of fish. No difference was also found in protein efficiency ratio among D1, D2 and D3. Similar to growth parameters, total fish production was highest in D1, intermediate in D2 and D3; and lowest in D4. Apparent digestibility coefficients of dry matter, protein and lipid were highest (P < 0.05) in D1 and lowest in D4. The economic analysis revealed that the benefit cost ratio was ranked by D₃ (1.81), D₂ (1.71), D₁ (1.66) and D₄ (1.46) respectively. Upon considering the overall performances and unavailability of finite protein sources, it can be concluded that 70–85% fishmeal could be replaced with a mixture of MBM and PC (1:1) in practical diets for climbing perch.     

Are dual-purpose and male layer chickens more resilient against a low-protein-low-soybean diet than slow-growing broilers?

ABSTRACT

1. Although fattening dual-purpose types or male layer hybrid chickens appears more ethical than the common practice of culling day-old male layer chicks, the lower feed efficiency of these birds raises concerns. Replacing feed ingredients that compete with food production by those of lower value for human nutrition would be beneficial.

2. Lohmann Dual (LD), a modern dual-purpose type, Lohmann Brown (LB), a male layer hybrid, and Hubbard JA 957 (HU), a slow-growing broiler type, were fattened for nine weeks on two diets (control or ?20% crude protein; n = 6 × 12 birds). Growth, carcass and meat quality were analysed.

3. Growth performance of HU exceeded that of LD and especially of LB. The growth depression caused by the low-protein diet fed to LD (?7%) was only half of that found in HU (?13%). The LD fed the control diet had the same feed efficiency as the HU fed the low-protein diet. Even the LB had a lower performance and feed efficiency with the low-protein diet in growth. There was a gradient in carcass properties (weight, dressing percentage, breast meat yield, breast proportion and breast angle) from HU to LD to LB, with some additional adverse effects of the low-protein diet especially in HU. There were some breed differences in fatty acid profile in the intramuscular fat.

4. In conclusion, the dual-purpose type used complied with regulations for Swiss organic poultry systems in terms of growth rate and was found to respond less when fed a low-protein diet than the slow-growing broiler type. The LB males were inferior in all growth and carcass quality traits. Future studies need to determine the exact protein and amino acid requirements of dual-purpose and layer hybrid chickens and the economic feasibility of the systems, especially for organic farming.