不同饲养标准对杜寒杂交肉用绵羊生产和屠宰性能的影响

本试验通过比较不同饲养标准杜寒杂交肉用绵羊增重、器官发育、屠宰性能及肉品质的差异,确定适宜的饲养标准。采用单因素试验设计,选取体重为(28.30±0.86)kg的杜寒杂交F1代肉羊600只,随机分为4组,每组3个重复,每个重复50只。4组分别饲喂按照以下饲养标准配制的饲粮:本实验室(中国农业科学院饲料研究所农业部饲料生物技术重点实验室)提出的杜寒杂交肉用绵羊饲养标准、美国NRC(2007)、英国AFRC(1993)以及我国农业行业标准的《肉羊饲养标准》(NY/T 816—2004),分别记为CARS、NRC、AFRC和HB。试验期81 d,每3 d记录1次采食量,每20 d进行1次称重,当CARS组羊只的平均体重达到44 kg时,每组选取10只羊进行屠宰,测定其屠宰性能、组织器官重量和肉品质等指标。结果表明:不同组羊只的实际干物质采食量,NRC组AFRC组CARS组HB组,其中NRC组与CARS和HB组间差异显著(P0.05),其他组间差异均不显著(P0.05);平均日增重和胴体重,CARS、HB、AFRC组间差异均不显著(P0.05),且均显著高于NRC组(P0.05);饲料转化率各组间存在显著差异(P0.05),CARS组HB组AFRC组NRC组;屠宰率,CARS组显著高于NRC组(P0.05),与HB、AFRC组间差异均不显著(P0.05);CARS组羊只的心脏、肝脏、肾脏重量占宰前活重比例显著高于其他组(P0.05);背最长肌失水率、肌肉色亮度、红度和黄度值,各组间均无显著性差异(P0.05)。结果提示,杜寒杂交肉羊在不同饲养标准下的实际日增重200~220g,从增重和屠宰性能上来看,CARS制订的饲养标准与国外饲养标准相比具有明显优势。     

Sex‐dependent responses of perch to changes in water clarity and temperature

Rising temperatures and decreasing water transparency of lakes have strong wide ranging effects on fish. Fish responses to various changes in the environment are usually species‐dependent, but responses may also vary within species. In general, large individuals are considered to be more sensitive to environmental variation due to higher energy demand, than smaller individuals. Similarly, large individuals require more food to maintain bodily functions and are thus more sensitive to resource and food scarcity. These size‐specific responses to environmental gradients are also sex‐dependent in species that exhibit sexual size dimorphism (SSD). We studied in enclosures with short‐term experiments how rising temperatures and decreasing water transparency regulate the feeding rates of female and male European perch (Perca fluviatilis L.). To explore experimental results, we calculated perch SSD in nine lakes with varying environmental conditions using previously collected field data. The results of the experiments revealed that the combined effect of water transparency and temperature on the feeding rate of fish is gender‐dependent: feeding rate of females decreased more than that of males. The experimental results were also supported by field data that revealed a negative relation between water transparency and the magnitude of SSD in perch. Our results suggest that rising temperatures and decreasing water transparency may potentially decrease fish size in a sex‐dependent manner. As female size is one of the main demographic traits determining the reproductive success of a fish population, changing environments may have unexpected and far‐reaching consequences on fish population dynamics.     

东海和黄海南部七星底灯鱼摄食习性的研究

根据2008年5月至2009年2月东海和黄海南部4个航次大面调查所获得的七星底灯鱼(Benthosema pterotum)胃含物样本,对其食物组成、摄食强度、食物多样性程度及营养级进行了研究.结果表明,东海和黄海南部七星底灯鱼属浮游动物食性,桡足类是其最主要的食物类群,其％ IRI值、质量百分比和个数百分比分别为75...     

鱼用促摄食物质研究方法

近些年,鱼粉的价格持续走高,使寻找优质高效的廉价替代蛋白源成为必然趋势。替代蛋白的使用又引起配方饲料诱食性和适口性下降的问题。因此,自20世纪70年代起,国内外学者进行了大     

Effects of supplementation of crystalline or coated methionine on growth performance and feed utilization of the pacific white shrimp,Litopenaeus vannamei

This study was conducted to evaluate the effects of supplementation of crystalline methionine or coated methionine supplemented in diets of Pacific white shrimp (Litopenaeus vannamei) on growth performance and feed utilization. Five iso‐nitrogen and iso‐caloric diets were prepared in which diets were supplemented with cellulose‐acetate‐phthalate (CAP), tripalmitin‐polyvinyl alcohol (TPA), acrylic resin (RES) coated l ‐methionine, hydroxyl‐methionine calcium (MHA) and crystalline l ‐methionine diet (MET, control), respectively. After 7 weeks, shrimp (0.81 ± 0.01 g in initial body weight) weight gain fed with MET and RES diets were significantly higher than that of the others (P < 0.05), while feed conversion ratio of shrimp fed with RES was significantly lower than the others (P < 0.05). Crude protein (as wet weight basis) in whole body of shrimp fed the RES diet was markedly higher than the others (P < 0.05). Methionine contents in muscle of CAP and MHA groups were significantly higher than those of MET group (P < 0.05). Apparently digestibility for essential amino acid of MET group was the highest except methionine. In the present study, RES coating methionine appeared to effectively improve feed protein utilization and enhance growth performance of Pacific white shrimp fed with low fishmeal practical diet.     

水产颗粒饲料投饵装置的原理与应用

本文分析了离心抛撒式投饵机、气力输送式投饵机和水力输送式投饵机等三种型式投饵机的技术原理与应用，指出水力输送式投饵机适合水产湿颗粒饲料自动投饵，但应解决好湿颗粒饲料机生产能力与水力输送式投饵机投饵能力的衔接配套、降低湿颗粒饲料在输送过程中的饵料溃散技术，以及根据养殖品种不同，分别进行抛投技术处理等问题。     

苜蓿饲喂肉牛育肥效果试验研究

[目的]为进一步探讨苜蓿草饲喂肉牛育肥效果。[方法]选择临床健康的1.5~2岁的西门塔尔杂种公牛60头、按年龄、体重、相同或相近的原则,配对分为试验组和对照组,每组30头。试验组饲喂养殖场周边地区的苜蓿草,经80d饲喂。[结果]表明:实验组日均增重1 320g/头,对照组日均增重1 170g/头,试验组比对照组提高12.82%(P0.05);每增加1kg净肉成本试验组14.39元、对照组为15.78元。试验组比对照组成本费减少9.67%。[结论]表明:苜蓿草饲喂肉牛增重效果显著。     

Enhancing highly unsaturated ω‐3 fatty acids in phase‐fed rainbow trout (Oncorhynchus mykiss) using Alaskan fish oils

Rainbow trout, average weight 185–187 g, were fed feeds containing menhaden oil, canola oil or fish oils (pollock, pink salmon or rockfish) produced from Alaskan seafood processing waste as the added oil for 8 weeks, at which time the fish weighed 391–411 g (average 404 g, pooled SE = 5.7). The fish were previously fed from 75 g average weight fed commercial feed containing poultry oil as the added oil. No significant differences were measured in final weight or feed conversion ratio among dietary treatment groups. Significant differences were found in fillet ω‐3 fatty acid (FA) levels from fish receiving fish oil‐supplemented feeds compared to those from fish receiving feeds containing canola oil. Fillet contents of eicosapentaenoic acid (EPA; 20:5ω3) and decosahexaenoic acid (DHA; 22:6ω3) were highest in the pollock oil treatment group, although all fish oils increased highly unsaturated ω‐3 FA contents (mg 100 g^?1) of fillets. Fish oil used through the production cycle was reduced by 25% by supplementing feeds with poultry oil during the middle phase of production (75–175 g) compared to using feeds containing fish oil throughout the production cycle. Fish oils recovered from Alaskan seafood processing waste were suitable alternatives to conventional fish oil as ingredients in rainbow trout production feeds.     

饲喂频率对妊娠母猪背膘厚和繁殖性能的影响

[目的] 研究饲喂频率对妊娠母猪背膘厚和繁殖性能的影响。[方法] 挑选加系杜洛克经产母猪480头,配种时按照胎次（2~7胎）、背膘厚（11~22 mm）相近的原则随机将母猪分为T1组（每天饲喂1次）和T2组（每天饲喂2次）,两组每天等量饲喂。T1组母猪220头,饲喂时间为8：00;T2组母猪260头,饲喂时间为8：00和15：00,每次饲喂量为总量的一半,定位栏饲养。[结果] ①饲喂频率不影响妊娠56 d、开配-妊娠56 d的背膘厚（妊娠56 d背膘厚-开配背膘厚）（P>0.05）;T2组妊娠110 d（P=0.06）、妊娠56-110 d（P=0.09）背膘厚（妊娠110 d背膘厚-妊娠56 d背膘厚）有高于T1组的趋势。②饲喂频率对窝产总仔数、活仔数、死胎数、木乃伊胎数、初生窝重以及初生个体重均无显著（P>0.05）影响。③在三胎母猪中,T2组妊娠110 d（P=0.01）、妊娠56-110 d（P=0.04）背膘厚均显著高于T1组;五胎及以上母猪,T2组妊娠56-110 d（P=0.08）背膘厚有高于T1组的趋势。④饲喂频率不影响二胎母猪窝产总仔数、死胎数、木乃伊胎数、初生窝重以及初生个体重（P>0.05）,但二胎母猪中T2组活仔数有高于T1组的趋势（P=0.07）。[结论] 饲喂频率由每天两餐减少到每天一餐不会对母猪的繁殖性能产生不利影响。