饲粮短期高剂量添加天冬氨酸镁对猪肉品质的影响

本试验研究了在基础日粮中短期添加不同水平的天冬氨酸镁对猪肉品质的影响。试验共分4个处理,每个处理6头猪。处理组镁(天冬氨酸镁)的添加水平分别为0、1 500、2 500和3 500 mg/kg。结果表明:屠宰前7 d饲粮添加天冬氨酸镁提高了猪肉品质,背最长肌肉中镁的含量分别比对照组提高了10.35%(P<0.05)、16.83%和18.61%(P<0.01),血清中镁的浓度分别比对照组增加了14.29%、27.14%和34.29%(P<0.01);显著提高了猪肉的初始pH(6.16~6.50)和最终pH(5.61~5.75)(P<0.05);对肉色评分改善显著(P<0.05);显著降低了滴水损失(P<0.05);但对猪的屠宰率、瘦肉率、背膘厚、眼肌厚度和肌肉中胶原蛋白含量等无显著影响(P>0.05)。回归分析结果表明:当镁的添加量在2 500~3 200 mg/kg时,对pH、滴水损失和肉色的改善作用达到最大,此时血清和肌肉中镁的含量约为0.90 mmol/L和241 mg/kg。     

Changes in hormones, growth factor and lipid metabolism in finishing pigs fed betaine

An experiment was conducted to investigate the effect of dietary betaine supplementation on carcass characteristics, hormones, growth factor and lipid metabolism in finishing pigs. Forty-eight crossbred barrows and gilts (Seghers × Seghers × Duroc) weighing about 55 kg were divided into two groups, each with three replicates of eight pigs (four barrows and four gilts) per replicate, and fed corn–soybean meal basal diets supplemented with 0 and 0.125% betaine for 42 days. At trial termination, two pigs (one barrow and one gilt) weighing about 90 kg were selected from each replicate and slaughtered for analyses. The results showed that betaine increased carcass lean percentage and longissimus muscle area by 5.19% (P < 0.01) and 17.85% (P < 0.01), respectively, and decreased carcass fat percentage and average backfat thickness by 13.07% (P < 0.01) and 10.30% (P < 0.05), respectively. Serum growth hormone, insulin-like growth factor I, free triiodothyronine, free thyroxine and insulin levels in pigs fed betaine were elevated by 45.61% (P < 0.01), 55.50% (P < 0.01), 57.95% (P < 0.01), 51.80% (P < 0.01) and 42.34% (P < 0.05), respectively. Fatty acid synthase activity in the 10th rib subcutaneous adipose tissue was decreased by 24.35% (P < 0.05) with betaine supplementation, whereas hormone-sensitive lipase activity was significantly increased (P < 0.05). Meanwhile, serum free fatty acids concentration in betaine-fed pigs was 25.75% higher compared to controls (P < 0.01). The study suggested that betaine could induce changes in hormones and growth factor in finishing pigs, and therefore could inhibit fat synthesis through reducing lipogenic enzymes activities and promote fat degradation by increasing hormone-sensitive lipase activity, with a resultant decrease in adipose tissue mass and improvement in carcass characteristics.     

无磷酸氢钙日粮对生长猪的影响研究

将48头杜×长×大三元杂交生长猪随机分为两组,分别饲喂正常磷水平日粮和无磷酸氢钙日粮,结果表明:与正常磷水平日粮相比,无磷酸氢钙日粮可显著提高磷的表观消化率(P<0.05),增加猪场的纯收入,减少粪中磷的排放以保护猪场周边的生态环境。     

重庆市致病性大肠杆菌的血清型鉴定

从重庆市各地发生典型仔猪黄、白痢猪的肛拭粪样及死亡猪的心血和肝脏中分离鉴定出173株致病性大肠杆菌,用20种大肠杆菌O抗原单价血清进行了血清学鉴定。结果表明:173株分离菌有87株能定型,分属14种血清型,其中以O101(17.2%)、O8(14.9%)、O20(14.9%)、O64(11.5%)、O45(9.2%)、O149(8%)等6种为优势血清型。同一地区存在多种血清型,大多数地区有本地的优势血清型。不同地区的优势血清型有的相同,有的不同。     

Effects of different types of dietary non-digestible carbohydrates on the physico-chemical properties and microbiota of proximal colon digesta of growing pigs

The effect of different types of fibre on the intestinal digesta and microbial diversity was evaluated in growing pigs. The animals were fed during forty-two days with one of four experimental diets including a control group, a diet enriched with resistant starch type I, by coarse ground corn, and other two diets containing sugar beet pulp (8%) and wheat bran (10%) (as sources of soluble and insoluble non-starch polysaccharides respectively). Body weight (BW) and average daily feed intake (ADFI) were assessed at day 7, 21 and 42. Luminal samples of digesta from proximal colon were collected to analyse water retention capacity (WRC), concentration of short-chain fatty acids (SCFA) and the microbial diversity. Overall, animals fed with higher amounts of non-digestible carbohydrates had lower ADFI and BW. Sugar beet pulp provoked an increase of WRC, a higher concentration of SCFA, and a more stable microbial diversity throughout the experimental period. On the other hand, animals fed with wheat bran presented a lower bacterial diversity.     

早期断奶仔猪营养性腹泻的分析及防治

仔猪腹泻是一种严重制约养猪业发展的疾病,其发生由应激、环境、营养等多种因素造成。本文主要从营养方面阐述了早期断奶仔猪发生腹泻的原因,并综合近年研究资料,论述了各种营养因素对仔猪营养性腹泻的改善作用,为研究合理的断奶仔猪日粮提供理论依据。     

Genome-wide Association Study on Alive Litter Size Trait in Bama Xiang Pigs

In order to identify the molecular markers related to alive litter size of Bama Xiang pigs,the genome-wide association study (GWAS) was used to map and screen the candidate genes affecting the alive litter size trait.Ear tissue samples of 297 Bama Xiang pigs with multiple parity records were collected,and DNA was extracted and genotyped by porcine 50K SNP beadchip.After quality control and genotype imputation,the alive litter size of Bama Xiang pigs were GWAS by Tassel.The results showed that the average number born alive per litter of Bama Xiang pigs increased gradually with the increasing of parity in the range of 1-9 parities.A total of 32 816 SNPs were obtained after quality control and filtration.8 SNPs related to alive litter size of Bama Xiang pigs were screened by genome-wide association analysis,which were significant at genome or chromosome level.Based on the enrichment analysis of the coding genes in the region between 500 kb upstream and downstream of the associated significant SNP loci,and the QTL regions and gene functions related to porcine reproductive traits,4 genes (CAPZB,MSH3,CITED2 and HSD17B7) were finally identified to be candidate genes related to alive litter size of Bama Xiang pigs.     

铜的来源和水平对生长猪生长性能禾粪铜排出量的影响

选用平均体重29．6kg的三元杂（杜×大×长）生长猪144头，按随机区组设计分为6个处理。饲粮中分别添加0、100、200mg／kg硫酸铜、200mg／kg碱式氯化铜、100mg／kg小肽铜、100mg／kg复合氨基酸螯合铜（以铜含量计）。结果表明：100mg／kg小肽铜和100mg／kg复合氨基酸螯合铜均能有效提高生长猪日增重和日采食量，其促生长效果与200mg／kg硫酸铜无显著（P〉0．05）差异，而粪中铜含量分别下降了36．8％和48．4％（P〈0．05）。     

不同氟水平对生长育肥猪毒性的研究

96头始重(24.14±1.12)kg的杜长大三元杂交猪,随机分为4组。第1组为对照组,饲喂基础日粮(含氟量37.39mg/kg),第2、3、4组分别饲喂含氟(以NaF形式添加)量为100、150、200mg/kg的日粮,研究日粮中不同氟水平对猪生长性能和血清某些生化指标的影响,并探讨了氟在肝、肾和肌肉中的沉积,饲料氟和粪氟、血清氟、尿氟之间的相关关系。结果表明,第3、4组猪增重与对照组相比分别降低8.86%(P<0.05)和9.81%(P<0.05),料重比分别升高7.36%(P<0.05)和8.07%(P<0.05)。第4组血清钙、镁、白蛋白含量和碱性磷酸酶的活力与对照组相比分别降低了17.33%(P<0.01)、29.91%(P<0.01)、10.75%(P<0.05)和33.71%(P<0.01)。第3、4组肝、肾和肌肉氟含量与对照组相比显著增加(P<0.05)。各试验组粪氟、血清氟、尿氟含量随饲料中氟含量的增加而升高,且各组间差异极显著(P<0.001),饲料氟与粪氟、血清氟、尿氟含量相关系数分别为0.943(P<0.01)、0.911(P<0.01)和0.959(P<0.01)。     

膨化与加酶玉米对断奶仔猪生长性能和肠黏膜形态的影响

通过2个饲养试验，研究了膨化及加酶处理玉米对断奶仔猪的生长性能和肠黏膜形态的影响。试验一分别用普通玉米、膨化玉米、普通玉米加酶及膨化玉米加酶为主要能量原料的饲料饲喂仔猪做4种处理，每个处理6个重复，定时记录体质量和耗料量．计算日增重、日采食量和料肉比。结果表明，膨化和加酶玉米均可提高日增重，降低料肉比。试验二分别用普通玉米、膨化玉米、普通玉米加酶及膨化玉米加酶为主要能量原料的饲料饲喂仔猪做4种处理，每个处理6个重复，分别在断奶后第14天和第28天各屠宰1头公猪。取十二指肠、空肠前、中、后段以及回肠做组织切片，观察其黏膜厚度、绒毛高度、隐窝深度和绒毛宽度。结果表明，断奶后14d，与普通玉米组相比，膨化玉米组和加酶玉米组都显著提高了十二指肠的绒毛高度，二者共同处理组使十二指肠的绒毛高度极显著提高；2种处理组都显著降低了空肠中段的隐窝深度；显著增加了十二指肠、空肠前段、后段和回肠的黏膜厚度。断奶后28d，2种处理组都显著增加了十二指肠的黏膜厚度。