不同杂交组合商品猪的肥育性能与胴体品质研究

本研究选用二元长大（L×Y）、三元杜长大（D×LY）、四元皮杜长大（PD×LY）三个杂交组合猪群为实验动物,进行生长发育性能、胴体品质性状测定,旨在为优质肉高效配套杂交组合筛选提供理论依据。研究表明：PD×LY日增重、料肉比及屠宰率最优,日增重、屠宰率与L×Y差异显著（P〈0．05）;PD×LY眼肌面积、后腿比例分别为48．09cm2、34．23％,为三组合中最高,并与L×Y差异显著（P〈0．05）,与D×LY组差异不显著（P〉0．05）。     

Intake, live animal scores/measurements and carcass composition and value of late-maturing beef and dairy breeds

The objectives of this study were to compare the progeny of 1) late-maturing beef with dairy breeds and 2) Charolais (CH), Limousin (LM), Simmental (SM) and Belgian Blue (BB) sires bred to beef suckler dams, for feed intake, blood hormones and metabolites, live animal measurements, carcass traits and carcass value in bull and steer production systems. The bull system included 50 late-maturing beef breeds and 22 Holsteins (HO) slaughtered at approximately 15 months of age, whereas the steer system consisted of 56 late-maturing beef breeds and 23 British Friesians (FR) slaughtered at approximately 24 months of age. Beef breeds were suckled until approximately 8 months of age, while dairy breeds were artificially reared until weaning at approximately 3 months of age. All animals were finished on an ad libitum concentrate diet. Mean live weight, live weight gain, carcass gain and feed efficiency were greater (P < 0.05) in beef than dairy breeds in both systems during the finishing period when offered concentrates. Although there was no difference in feed intake between beef and dairy breeds, intake expressed relative to live weight was lower (P < 0.001) in beef breeds in both systems. At 10 months of age and pre-slaughter, beef breeds had higher (P < 0.001) muscularity scores and greater scanned muscle depth (P < 0.001) than their dairy contemporaries. Carcass weight, kill-out proportion, carcass conformation score, meat proportion and value were greater (P < 0.001) and carcass fat and bone proportions were lower (P < 0.05) in beef than dairy breeds in both systems. Insulin concentrations were lower (P < 0.001) in beef than dairy breeds, whereas there was no difference in blood metabolites or IGF-1 concentrations. Feed intake expressed relative to live weight or feed efficiency did not differ between CH, LM, SM or BB sired progeny. Muscularity scores were greater (P < 0.05) in BB than SM, whereas skeletal scores were lower (P < 0.05) in LM than SM. Limousin had lower (P < 0.05) carcass gain per day of age than CH and SM, whereas SM had a lower (P < 0.05) carcass conformation score than BB and CH and a higher (P < 0.05) carcass fat score than CH. Simmental had a lower (P < 0.05) carcass meat proportion and a higher (P < 0.05) carcass fat proportion than CH, LM and BB, which were similar (P > 0.05). The improvement obtained for beef over dairy breeds in live weight gain was 12%, while the improvements in carcass gain and meat produced was 24% and 33%, respectively. This demonstrates that the importance of carcass data contributing to breed comparison studies cannot be over-emphasised.     

Evaluation of estimated genetic merit for carcass weight in beef cattle: Blood metabolites, carcass measurements, carcass composition and selected non-carcass components

In Ireland, a new beef genetic index has been developed. Growth rate is expressed as expected progeny difference for carcass weight (EPD_CWT) and is estimated on an across-breed basis. Cross-breeding of dairy cows with both Aberdeen Angus and Belgian Blue beef sires is widely practised. The objective of this study was to compare blood metabolites, slaughter traits and carcass composition of progeny from Holstein–Friesian dairy cows and Aberdeen Angus (AA), Belgian Blue (BB), Friesian (FR) and Holstein (HO) sires. The AA and BB sires were selected, within breed, to be of either high (H) or low (L) estimated genetic merit for carcass weight. A total of 170 male progeny from spring-calving cows and 42 sires (10 AA, 13 BB, 7 FR and 12 HO) were artificially reared indoors and managed together until the end of their second grazing season when they were assigned to either a Light (560 kg) or Heavy (620 kg) slaughter weight. Blood metabolite concentrations were measured six times throughout life and feed intake was recorded during the first and second winter. Carcass measurements and selected non-carcass components were recorded after slaughter and the right side of each carcass was dissected into lean, fat and bone. Differences in blood metabolite concentrations amongst genetic groups were negligible although there were some effects of the prevailing level of nutrition. M. longissimus area scaled for carcass weight was 0.220, 0.221, 0.260, 0.255, 0.212 and 0.208 (SE 0.004) cm²/kg for AAH, AAL, BBH, BBL, FR and HO, respectively. Carcass measurements scaled for carcass weight were greater for L, AA, HO and the dairy strains than for H, BB, FR and the beef breeds, respectively. There was no effect of estimated genetic merit for carcass weight on carcass composition. Statistically significant interactions between genetic merit and beef breed existed for some traits with the genetic merit effect largely evident for AA only. BB and the beef breeds had more lean, less fat and more high value lean in the carcass than AA and the dairy strains, respectively. It is concluded that genetic group had little effect on blood metabolite concentrations but there were some feeding level effects. Estimated genetic merit for carcass weight affected carcass weight, m. longissimus area and carcass measurements scaled for carcass weight but the effects were confined to AA. There were large effects of beef breed and dairy strain on carcass composition.     

淮南麻黄鸡选育过程中产肉性能的比较研究

研究比较了1、3、59、世代淮南麻黄鸡8周龄的体重、屠宰性能和肌肉部分品质。结果表明:以8周龄体重作为选育目标,淮南麻黄鸡选育群早期生长速度得到了逐步提高;屠宰性能和肌肉品质在世代间差异均不显著。表明在优质肉鸡选育中,在保持其肉质基本不变的同时,可以适当提高其早期生长速度。     

21～42日龄肉鸡能量和蛋白质需要量的研究

以商品代艾维茵肉鸡为供试动物,设置3个日粮代谢能(ME)水平,分别为12.55、12.97和13.38 MJ/kg;4个粗蛋白(CP)水平,分别为18.5%、19.0%、19.5%和20.0%.采用3×4因子设计进行饲养试验, 研究日粮ME和CP水平对22～42日龄肉鸡生产性能、胴体性能以及肉品质的影响.结果表明:(1)日粮ME水平对22～42日龄肉鸡的日均采食量、平均日增体质量、料重比和21日体质量影响极显著(P<0.01);日粮CP水平对22～42日龄肉鸡的日均采食量影响不显著(P>0.05),但对平均日增体质量、42日体质量和料重比影响极显著(P<0.01).日粮ME和CP的互作对22～42日龄肉鸡料重比影响极显著(P<0.01);较高的日粮ME水平和CP水平可获得理想的生产性能;(2)日粮ME水平对22～42日龄肉鸡半净膛率、腿肌率和腹脂率影响极显著(P<0.01),对屠宰率影响显著(P<0.05),对全净膛率和胸肌率影响都不显著(P>0.05);日粮CP水平与22～42日龄肉鸡的胸肌率呈正相关,对其他胴体性能指标影响不显著(P>0.05);(3)随日粮ME水平增加,腿肌的红度(a*)先降低后增加,但对胸肌红度(a*)影响不显著(P>0.05);胸肌和腿肌的黄色度值(b*)都与日粮ME和CP水平呈正相关;日粮ME水平对胸肌的亮度(L*)影响不显著(P>0.05);(4)胸肌的PH值与日粮ME水平呈负相关,腿肌的pH值随日粮CP水平的升高呈先上升后下降趋势;腿肌的持水率与日粮ME水平呈正相关.通过本试验并结合生产实际认为: 22～42日龄肉鸡适宜的ME水平为12.97MJ/kg,CP水平为19.0%～20.0%之间.     

麻城黑山羊及杂交后代的胴体品质与肉质特性

分析麻城黑山羊及杂交后代胴体品质与肉质特性,探讨麻城黑山羊的改良和新品系选育。选用麻城黑山羊(Ⅰ,对照组)、波尔山羊×麻城黑山羊(Ⅱ)、麻城黑山羊×波麻F1(Ⅲ)、波麻F1×波麻F1(Ⅳ)和波尔山羊×波麻F1(Ⅴ)5组,以放牧加补饲的方式育肥,试验期90d,于试验始日及第90天称量,试验结束时于每个组选取12只屠宰并分析胴体品质和肉质性状。结果表明,杂交后代的肥育性能较麻城黑山羊组均有所提高,其中Ⅱ、Ⅲ、Ⅴ组的日增量极显著高于麻城黑山羊(P<0.01);杂交后代的胴体性状较麻城黑山羊有较大提高,其中Ⅱ、Ⅴ组的屠宰率和净肉率分别显著、极显著高于麻城黑山羊(P<0.05,P<0.01),Ⅱ、Ⅳ组的肉骨比显著高于麻城黑山羊(P<0.05),Ⅱ、Ⅴ组的眼肌面积极显著高于麻城黑山羊(P<0.01);各组间主要肉质性状除麻城黑山羊宰后24h的pH显著高于Ⅱ、Ⅳ组(P<0.05)外,其余差异均不显著(P>0.05);Ⅲ组的Fe含量显著高于麻城黑山羊(P<0.05),杂交后代肌肉的氨基酸组分完全,且氨基酸总量和鲜味氨基酸含量均高于麻城黑山羊。结果显示,Ⅱ组是肉羊生产理想的杂交组合,Ⅴ组可用于进一步培育麻城黑山羊新品系的研究。     

CALCA 基因遗传变异及其与肉质性状关联分析

旨在分析早胜牛及其杂交牛CALCA基因第4外显子的多态性及其与肉质性状的相关性,发现与肉质性状相关的分子标记,为加快肉牛选育进程提供参考。利用PCR-SSCP 技术对早胜牛、南杂牛、秦杂牛和西杂牛共362个个体的CALCA基因第4外显子进行了遗传变异检测,并运用SPSS 17．0软件对早胜牛（平凉类群）遗传变异与经济性状关联性进行了分析。结果表明,CALCA基因第4外显子存在2个突变位点T3237 A和G3289 A,并检测到AA和AB 2种基因型。相关性分析表明,CALCA基因突变位点与剪切力、眼肌面积、热胴体重和熟肉率显著相关（P＜0．05）,AA基因型个体剪切力、热胴体重和熟肉率显著高于AB基因型个体（ P＜0．05）,而AB基因型个体眼肌面积显著高于AA基因型个体（P＜0．05）,其他性状在各基因型间差异不显著。因此,初步推测CALCA 基因的突变位点可以作为评定早胜牛肉质性状的遗传标记。     

人重组溶菌酶对肉鸡生产性能及胴体品质的影响

研究人重组溶茵酶对肉鸡生产性能、胴体品质的影响,探讨其替代抗生素的可能性及其在肉鸡日粮中添加的最佳剂量。试验结果表明,添加0．3％人重组溶菌酶促生长效果最好。     

The relationship of various muscular and skeletal scores and ultrasound measurements in the live animal,and carcass classification scores with carcass composition and value of bulls

The relationships of live animal muscular and skeletal scores and ultrasound measurements and carcass conformation and fat scores with carcass composition and value were determined using 74 bulls. The animals consisted of 53 late-maturing breed crosses and 21 Holstein–Friesian slaughtered at 13 to 17 months of age. They were offered concentrates ad-libitum and 1 kg of grass silage dry matter per head daily for the final 139 day finishing period. Live animal muscular and skeletal scores and ultrasonic muscle and fat depth measurements of the M. longissimus dorsi were recorded at 8 to 12 months of age and pre-slaughter. Following slaughter, carcasses were classified for conformation and fatness and the right side of each carcass was dissected into meat, fat and bone. Carcass conformation and fat scores, (scale 1 to 15) ranged from 4.7 to 14.4 and 2.7 to 11.5, respectively. Pre-slaughter muscular scores showed significant positive correlations with kill-out proportion (r = 0.82), carcass meat proportion (r = 0.72), conformation score (r = 0.94), carcass value (r = 0.72), and the proportion of high-value meat cuts in the carcass (r = 0.49), and significant negative correlations with carcass bone (r = − 0.89) and fat (r = − 0.32) proportions. The associations between pre-slaughter muscular scores and proportion of high-value cuts in meat, perinephric plus retroperitoneal fat and fat score were not significant. Corresponding correlations with muscular scores at 8 to 12 months of age were generally lower than those recorded pre-slaughter. Correlations of ultrasound muscle depth with carcass traits showed similar trends but lower values to those obtained using the muscular scoring procedure. Ultrasound fat depth pre-slaughter was positively correlated with carcass fat proportion (r = 0.56) and fat score (r = 0.54), and negatively correlated with carcass meat proportion, proportion of high-value cuts and carcass value. Correlations with other carcass traits were not significant. Correlations of live animal skeletal scores with carcass traits were generally non-significant. A one unit (scale 1–15) increase in carcass conformation score was associated with significant increases in kill-out proportion, meat yield and carcass value of 11.9 g/kg, 11.9 g/kg and 5.8 cent/kg, respectively. Corresponding effects for a one unit change in fat score were − 2.9 g/kg, − 11.1 g/kg and − 4.9 c/kg. In conclusion, live animal muscular scores and ultrasound measurements and carcass conformation and fat scores were shown to be useful predictors of carcass composition and value.     

Effect of different dietary ratios of sunflower and linseed oils on growth and carcass traits of rabbits

As part of an experiment aiming to modify the meat fatty acid profile, this work studied the growth and carcass traits as affected by various dietary ratios of sunflower oil and linseed oil. A diet without added oil served as a control (C). Four other diets were equally 4% oil-enriched but they differed in the incorporation ratios of sunflower oil (S) to linseed oil (L), i.e. 4% S to 0% L (diet 4%S), 3% S to 1% L (diet 3:1%SL), 2% S to 2% L (diet 2:2%SL) and 0% S to 4% L (diet 4%L). The oil-rich diets had slightly higher digestible energy contents (11.4 vs 10.6 MJ/kg) than the C feed. In each group 10 litters of 7 to 9 Pannon White kits per litter were studied in the pre-weaning period from 21 to 35 days old. Growth and slaughter traits were assessed with 50 and 30 rabbits per group, respectively. No significant effects of diets were found on litter and doe performances. The only significant differences in growth performance of the C, 4%S, 3:1%SL, 2:2%SL and 4%L rabbits were for the 35–49 day feed intake (88, 86, 84, 84 and 83 g per day, respectively, P = 0.046), the 35–84 day growth rate (36, 38, 37, 35 and 37 g/day, P = 0.034) and the 84-day body weight (2608, 2703, 2664, 2565 and 2628 g, respectively, P = 0.022). There were several significant differences in carcass traits including the weight of reference carcass (1357, 1391, 1388, 1380 and 1369 g, respectively, P = 0.004) and left longisimus dorsi meat (78, 79, 81, 81 and 76 g, respectively, P = 0.046) of rabbits. The diets had major effects on the L*, a* and b* colour values (lightness, redness and yellowness) of meat and fat. Carcass colour of the C and 4%S rabbits was closer and the 4%L rabbits was further from the European consumer's preference of light coloured, less red and slightly yellow rabbit meat. Our result reveals the importance of age and body weight at slaughter. Taking the growth and slaughter performances and, the recent belief of human health benefits from lower n− 6/n− 3 FAs dietary ratios into account, the 2:2%SL diet seems most appropriate if the interests of the raisers, meat processors and buyers are considered equally.