玉米蛋白多肽对豁眼鹅屠宰性能及脏器系数的影响

以昌图豁眼鹅为研究对象,在基础日粮中添加不同剂量玉米蛋白多肽,通过检测豁眼鹅的屠宰性能及脏器系数,为玉米蛋白多肽在畜禽饲料中的应用奠定理论基础.选择1日龄昌图豁眼鹅240只,公母各半,随机分为4组,对照组饲喂基础日粮,其他组分别在每千克基础日粮中添加100、300、500 mg的玉米蛋白多肽,并分别于30日龄和60日龄进行宰杀,检测屠宰性能及脏器系数.结果表明,屠宰性能方面,玉米蛋白多肽的添加可以增加豁眼鹅的半净膛率、全净膛率,且随着玉米蛋白多肽添加剂量的增加而增加,尤以中剂量组增加显著;脏器系数方面,玉米蛋白多肽的添加可以降低肝脏指数和胸腺指数;但玉米蛋白多肽对其他屠宰性能指标(活体重、胴体重)及脾脏指数和法氏囊指数的影响不明显.     

添加不同水平玉米蛋白多肽对鹅血清一氧化氮水平的影响研究

为了探讨日粮中添加不同水平的玉米蛋白肽对鹅血清NO水平的影响,研究选用1日龄昌图豁鹅240只,采取单因子完全随机设计分为4组,其中对照组饲喂基础日粮,高、中、低3个剂量组分别在每千克基础日粮中添加500,300,100 mg玉米蛋白多肽。饲养30,60天时采集鹅血制备血清,采用紫外分光光度法检测鹅血清中一氧化氮(NO)含量。结果表明:随着日龄的增加,鹅血清中NO含量有降低的趋势;一定时间内(30 d)日粮中添加一定水平的玉米蛋白多肽可以增加鹅血清中NO的含量,但添加时间过长(60 d)则会降低NO含量,具体机理有待进一步探讨。     

玉米蛋白多肽对豁眼鹅血清离子水平及肉品质的影响

为探讨玉米蛋白多肽对鹅血清离子水平和肉品质的影响,选取1日龄辽宁豁眼鹅240只,随机分为4组,每组设6个重复,每个重复10只。对照组饲喂基础日粮,低、中、高3个剂量组分别于每千克基础日粮中添加玉米蛋白多肽100mg、300mg和500mg。分别于30日龄和60日龄时采样,每组12只,共48只,称重、宰杀,采集血样及腿肌,分别检测血清离子及肉色、R值、嫩度指标。结果显示:玉米蛋白多肽高、中、低剂量组血清钾离子水平分别下降42.88%、25.37%和30.25%,均高于对照组(14.88%),高、中剂量水平可明显提高血清中游离钙和结合钙水平;与对照组相比,短时间(30d)添加使腿肌嫩度减小,显著增加中、高剂量组鹅的腿肌肉色指数及各组腿肌R值;但较长时间添加(60d),高、低剂量均可增加肌肉嫩度,中剂量显著降低肉色指数和R值,高剂量对肉色指数表现为增强效应。综上,玉米蛋白多肽可能通过影响鹅血清离子水平和腿肌的肉色指数、嫩度及R值,从而影响鹅肉品质及机体代谢,其中以高剂量(500mg/kg)30d效果较为明显。     

玉米蛋白多肽对昌图豁鹅血液生理生化指标的影响

本研究旨在探讨玉米蛋白多肽对昌图豁鹅血液生理生化指标的影响.选取1日龄昌图豁鹅240只,随机分为4组,每组设6个重复,每个重复10只.对照组饲喂基础日粮,低、中、高3个剂量组分别在每千克基础日粮中添加玉米蛋白多肽100、300和500 mg.分别于鹅只30和60日龄时采样,检测血液生理生化指标.结果表明:30日龄时,低剂量组白细胞计数显著高于对照组(P<0.05);高剂量组和低剂量组淋巴细胞计数显著高于对照组(P<0.05);中剂量组和低剂量组中值细胞计数极显著高于对照组和高剂量组(P<0.01);中性粒细胞计数,低剂量组显著或极显著高于其他3组(P<0.05或P<0.01),高剂量组显著低于对照组(P<0.05);低剂量组和中剂量组中值细胞百分比显著或极显著高于对照组(P<0.05或P<0.01);高剂量组血清葡萄糖含量极显著低于对照组(P<0.01);高剂量组血清磷、尿素氮含量显著高于对照组(P<0.05);中剂量组血清总胆红素含量显著高于对照组(P<0.05).60日龄时,各指标组问差异均不显著(P>0.05).由此得出,玉米蛋白多肽可通过使昌图豁鹅的血液生理生化指标发生变化,进而影响其机体代谢和免疫功能.     

添加玉米蛋白多肽对豁眼鹅血清酶及抗氧化指标的影响

本研究探讨添加不同剂量玉米蛋白多肽对豁眼鹅血清中酶水平及抗氧化指标的影响,利用全自动生化分析仪和紫外分光光度计分别检测高、中、低剂量添加玉米蛋白多肽日粮组以及对照组30、60 d时豁眼鹅血清中酶水平和抗氧化指标。结果表明:短时间(30 d)添加玉米蛋白多肽可使血清GPT、GOT、HBDH、LDH、CK、CKMB、GSH-Px、GSH和维生素C水平升高;较长时间(60 d)添加,所有试验组血清中CK、CKMB、HBDH、GSH水平降低,低剂量组血清中GPT、GOT、LDH水平降低,GSH-Px水平表现为中、低剂量水平添加使其增加,高剂量使其降低,高、中、低剂量组血清维生素C含量均升高。本研究表明玉米蛋白多肽可以作为鹅或其他家禽的饲料添加剂,以提高机体代谢水平、增强抗氧化力。     

锌对鹅铜锌超氧化物歧化酶和丙二醛含量影响变化的研究

试验选用120只1日龄鹅随机分成四组,A组喂以玉米、大豆为基础饲粮未加锌的饲料,另外3组在基础日粮中添加ZnSO4·H2O,使锌含量分别为40mg/kg(B组),110mg/kg(C组)和2000mg/kg(D组)。分别于15日龄、30日龄和55日龄测定铜锌超氧化物歧化酶(CuZn-SOD)活性和丙二醛含量变化。结果表明,在鹅血清和肝脏中,A、D组CuZn-SOD活性低于B、C组,C组的MDA含量在四组中最低。在整个试验过程中脾脏CuZn-SOD活性和MDA含量没有太大变化。该结果揭示了锌能影响鹅的抗氧化防御系统,锌添加量为110mg/kg时,可提高鹅抗氧化水平。     

脂肪酸合成酶基因mRNA在马身猪和大白猪3种组织中的发育性表达研究

为探究脂肪酸合成酶(fatty acid synthase,FAS)基因在猪不同组织中的发育性表达规律,本研究采用实时荧光定量PCR技术检测马身猪和大白猪7个阶段(初生、30、60、90、120、150和180日龄)肝脏、背最长肌和背部皮下脂肪3种组织中FAS基因mRNA的相对表达量。结果表明,品种间比较,FAS基因mRNA在马身猪和大白猪肝脏、背最长肌和背部皮下脂肪组织各生长发育阶段中的表达差异均达到显著或极显著(除肝脏组织初生阶段和背部皮下脂肪组织120日龄阶段)(P<0.05;P<0.01)。FAS基因mRNA在大白猪组织间的表达差异与生长发育相关,150和180日龄阶段,背部皮下脂肪组织中表达量极显著高于肝脏和背最长肌组织(P<0.01),初生、30日龄和90日龄阶段,背最长肌中的表达量极显著高于肝脏和背部皮下脂肪组织(初生阶段无脂肪组织样)(P<0.01);而马身猪整个发育过程中,背最长肌组织表现为优势组织,极显著高于其他2种组织(除120日龄阶段外)(P<0.01),脂肪组织表达量次之,肝脏组织中表达量较少。品种、日龄、组织及品种与日龄、组织与日龄的互作效应对FAS基因mRNA的相对表达量均有极显著影响(P<0.01)。FAS基因直接参与脂肪酸的合成,对猪肉质性状的遗传改良具有重要意义。     

叶酸添加水平对肉仔鸡肝脏中脂肪代谢相关基因表达和甲基化的影响

本试验旨在考察叶酸添加水平对肉仔鸡血清中脂蛋白脂肪酶(LPL)和脂肪酸合成酶(FAS)活性、过氧化物酶体增殖物激活受体γ(PPARγ)含量以及肝脏中脂肪代谢相关基因表达和甲基化的影响。选择1日龄爱拔益加(AA)肉仔鸡300只,随机分成3组,每组5个重复,每个重复20只。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加5和10 mg/kg叶酸的试验饲粮。试验期为42 d。结果显示:1)与对照组相比,饲粮中添加10 mg/kg叶酸显著降低了21日龄肉仔鸡血清中LPL活性(P<0.05);饲粮中添加5和10 mg/kg叶酸极显著降低了42日龄肉仔鸡血清中LPL活性(P<0.01),极显著提高了21和42日龄肉仔鸡血清中PPARγ含量(P<0.01),极显著降低了21和42日龄肉仔鸡血清中FAS活性(P<0.01)。2)实时荧光定量PCR结果发现,饲粮中添加5和10 mg/kg叶酸均未显著影响42日龄肉仔鸡肝脏中LPL和PPARγ基因的相对表达量(P>0.05),但均显著降低了FAS基因的相对表达量(P <0.05)。3)甲基化分析显示,饲粮中添加5和10 mg/kg叶酸均未显著影响42日龄肉仔鸡肝脏中LPL和PPARγ基因的甲基化比率(P>0.05),但饲粮中添加5 mg/kg叶酸极显著提高了42日龄肉仔鸡肝脏中FAS基因的甲基化比率(P<0.01)。由此得出,饲粮中添加5和10 mg/kg叶酸极显著降低了42日龄肉仔鸡血清中LPL和FAS的活性,极显著增加了PPARγ的含量,显著降低了肝脏中FAS基因的表达;此外,饲粮中添加5 mg/kg叶酸还极显著提高了42日龄肉仔鸡肝脏中FAS基因的甲基化水平。     

黄羽肉鸡日粮中添加胆汁酸盐对肠道黏膜转运蛋白及消化酶的影响

试验旨在研究日粮中添加不同水平的胆汁酸盐对黄羽肉鸡雏鸡肠道黏膜转运蛋白(SREBF1、FATP4)及消化酶(FAS、ACC)基因表达的影响。将420只雏鸡分为7组,试验1组为阴性对照组饲喂基础日粮,试验2组为阳性对照组,在基础日粮上添加0.02%泰乐菌素代替麸皮,试验3组、试验4组、试验5组、试验6组、试验7组分别用0.015%、0.025%、0.035%、0.045%、0.055%的胆汁酸盐代替麸皮。雏鸡饲养28 d,在28日龄时采集十二指肠、空肠、回肠和肝脏,通过实时荧光定量PCR技术对各组织相应目的基因进行表达量测定。结果显示:黄羽肉鸡不同组织SREBF1、FATP4、FAS、ACC mRNA的相对表达量均存在极显著差异(P<0.01);不同胆汁酸盐添加水平黄羽肉鸡肠道SREBF1、FATP4、FAS、ACC mRNA相对表达量存在极显著差异(P<0.01)。由此可见,黄羽肉鸡肠道营养转运蛋白SREBF1、FATP4及消化酶FAS、ACC基因表达具有肠段及胆汁酸盐添加水平的差异性。日粮添加0.055%胆汁酸盐,对于肠道整体营养转运蛋白及消化酶的基因表达影响最佳。     

木聚糖酶对AA肉鸡脂代谢及相关基因表达的影响

为了研究木聚糖酶对AA肉鸡脂代谢及相关基因表达的影响,试验采用出生重相近的AA肉仔鸡480只,公母各半,随机分为3组,每组8个重复,每个重复20只鸡,对照组饲喂玉米-豆粕型基础日粮,W组日粮用60%的小麦替代AA肉鸡日粮中玉米,WE组在W组日粮的基础上添加0.1%的发酵木聚糖酶,试验期为49 d,之后分别检测了AA肉鸡的腹脂率、血液生化指标以及腹脂和肌肉的脂肪型脂肪酸结合蛋白(A-FABP)和脂肪酸合成酶(FAS)基因的表达情况。结果表明:W组、WE组28,49日龄肉鸡的腹脂率显著降低(P0.05);W组49日龄葡萄糖(GLU)水平显著降低(P0.05),WE组肉鸡GLU、总胆固醇(CHO)、三酰甘油(TG)水平变化不显著(P0.05);W组肉鸡腹脂FAS基因和A-FABP基因的表达显著降低(P0.05),49日龄时W组肉鸡胸肌FAS、A-FABP基因表达显著降低(P0.05)。说明小麦日粮添加木聚糖酶可调节肉鸡脂代谢相关基因表达,降低肉鸡腹脂率,提高经济效益。     

Lipogenic gene expression in abdominal adipose and liver tissues of diet-induced overweight cats

The effect of overweight status on the expression of SREBP-1c and downstream lipogenic genes, such as ATP citrate lyase (ACL) and fatty acid synthase (FAS), in abdominal adipose and liver tissues was determined in cats using a diet-induced weight gain model. ACL and SREBP-1c mRNA expression was significantly reduced (～65% and 20%, respectively) in liver tissue, whereas FAS and SREBP-1c expression was significantly increased (～80% and 45%, respectively) in abdominal omental adipose tissue of overweight animals as compared to healthy animals. Additionally, ACL, FAS, and SREBP-1c expression was significantly reduced by ～50%, 75%, and 70%, respectively, in abdominal subcutaneous adipose tissue of overweight animals. Omental adipose tissue appeared to foster, whereas subcutaneous adipose and liver tissues appeared to defer lipid storage based on differences in SREBP-1c mRNA expression. Overall, reduced lipogenic gene mRNA expression patterns support the hypothesis that SREBP-1c expression is reduced in overweight and possibly obese cats, reflecting down-regulation of the lipogenic pathway to prevent further fat accumulation and weight gain.     

Effects of a high energy and low protein diet on hepatic and plasma characteristics and Cidea and Cidec mRNA expression in liver and adipose tissue of laying hens with fatty liver hemorrhagic syndrome

Cidea and Cidec are two members of Cell death‐inducing DNA fragmentation factor‐alpha‐like effector family proteins, which could be involved in lipid or fat metabolism. To better understand the roles of Cidea and Cidec in fatty liver hemorrhagic syndrome (FLHS), 150 healthy 155‐day‐old Hyline Brown laying hens were randomly divided into control group (fed with basic diet) and experimental group (fed with high‐energy low‐protein [HELP] diet). Analysis of the liver by tissue sectioning and hematoxylin and eosin staining showed that the HELP diet induced micro‐vesicular steatosis in laying hens. Subsequently, based on the liver color scores and the range of lipid accumulation observed in histological examination, we classified livers with <50% vacuolization as mild FLHS and >50% as severe FLHS. The results showed that the levels of Cidea and Cidec mRNA expression were markedly elevated in the liver and adipose tissues with FLHS and the levels of Cidea and Cidec mRNA expression in the liver with severe FLHS were significantly higher than that in the liver with mild FLHS. Thus, the present study revealed that the Cidea and Cidec genes may be involved in pathways of FLHS formation.     

夏季高温条件下饲粮中添加刺梨提取物对皖西白鹅生长性能、脂质代谢及肝脏中热休克蛋白70基因表达的影响

本试验旨在研究夏季高温条件下饲粮中添加刺梨提取物对皖西白鹅生长性能、脂质代谢及肝脏中热应激蛋白70(HSP70)基因表达的影响。挑选28日龄、体重相近的健康皖西白鹅150只,随机分成3组,即对照组、试验1组和试验2组,每组5个重复,每个重复10只鹅。对照组试验鹅饲喂基础饲粮,试验1组和试验2组试验鹅分别饲喂在基础饲粮中添加100和200 mL/kg刺梨提取物的试验饲粮。预试期7 d,正试期14 d,试验期间最高气温37℃,最低气温24℃,日平均气温31.6℃。饲喂2周后,每个重复挑选1只鹅屠宰,采集血样,并分离出肝脏,测定血清脂质代谢指标和肝脏中HSP70基因的相对表达量。结果表明:饲粮中添加刺梨提取物对皖西白鹅的平均日采食量和平均日增重均无显著影响(P0.05),但添加200 mL/kg刺梨提取物可显著降低料重比(P0.05);饲粮中添加100和200 mL/kg刺梨提取物均可显著提高血清高密度脂蛋白含量(P0.05),但对血清总胆固醇和甘油三酯含量无显著影响(P0.05);与对照组相比,试验1组和试验2组肝脏中HSP70基因的相对表达量均极显著提高(P0.01),同时试验1组肝脏中HSP70基因的相对表达量还极显著高于试验2组(P0.01)。由此得出,在夏季高温条件下,在皖西白鹅饲粮中添加刺梨提取物可提高饲料转化率、调节脂质代谢、上调肝脏中HSP70基因的表达,具有较明显的抗应激效果,且添加量为100 mL/kg时的抗应激效果优于添加量为200 mL/kg时。     

日粮中添加苜蓿草粉对肉鹅生长性能及肉质性状的影响

试验旨在研究日粮中添加不同比例的苜蓿草粉对四季鹅生长性能、体尺、屠宰性能、器官指数和肉质性状的影响。选取健康、体重相近的15日龄四季鹅256只（公母各半）,随机分成4组,对照组饲喂玉米-豆粕型基础日粮,3个试验组分别添加10%、20%和30%苜蓿草粉。每组4个重复,每个重复16只鹅。饲养至70日龄时,测量其各项体尺指标,每个重复选取4只鹅屠宰取样,测定屠宰性能、器官指数及肉质性质。结果表明：与对照组相比,日粮中添加不同比例的苜蓿草粉对四季鹅的平均日采食量、平均日增重、料重比、体斜长、龙骨长、胫围、半潜水长、胸宽、胫长、屠宰率、半净膛率、胸肌率等均无显著影响（P>0.05）,添加20%和30%苜蓿草粉显著提高了鹅的胸深（P<0.05）,添加30%苜蓿草粉显著降低了鹅的全净膛率（P<0.05）,添加10%苜蓿草粉显著提高了腿肌率（P<0.05）。此外,与对照组相比,苜蓿草粉组腹脂率均显著降低（P<0.05）,肝脏指数、空肠指数、回肠指数以及盲肠指数均显著提高（P<0.05）,但胸肌、腿肌的滴水损失同时也提高了（P<0.05）;10%、30%苜蓿草粉组十二指肠指数均显著提高P<0.05）。综上所述,在日粮中添加苜蓿草粉可改善四季鹅的屠宰性能（增加胸深、提高腿肌率、降低腹脂率）,提高器官指数（肝脏指数、十二指肠指数、空肠指数、回肠指数以及盲肠指数）,但会提高胸肌和腿肌的滴水损失;且添加过多的苜蓿草粉（30%）还会显著降低全净膛率。综合考虑,四季鹅日粮中以添加10%苜蓿草粉为宜。     

Study on Changes of Blood Chemistry Indexes,Hepatic Routine Nutritional Composition and Expression of Lipid Metabolism-associated Genes during the Recovery of Geese with Fatty Livers

This experiment aimed to determine the changes of body weight, liver weight, abdominal fat weight, hepatic routine nutritional composition, blood biochemistry indexes, as well as mRNA expression of lipid metabolism-associated genes during the recovery of Landes geese with fatty liver, which provided the basis for the further elucidation of the recovery or protection mechanism of goose fat liver.18 Landes geese were divided into three groups (6 gees in each group).Group 1 was control group, in which the geese were fed with boiled maize;Group 2 was the overfeeding group without recovery, in which the geese were overfed with a maize-based diet for 19 days;And group 3 was the overfeeding group with 20-day recovery, in which the geese were overfed with the maize-based diet for 19 days followed by feeding boiled maize for 20-day recovery.The results showed that compared with group 2, the body weight and liver weight of the geese in group 3 decreased extremely significantly (P<0.01), and the abdominal fat weights undecreased significantly (P>0.05);Moreover, the percentages of nutrients including water, ash, CP of livers in group 3 increased significantly (P<0.05), while the percentage of EE decreased significantly (P<0.05), but there were no significant difference for these variables between groups 1 and 3 (P>0.05) except water.In regard to blood biochemistry indexes, the contents of blood ALT, AST, TG and HDL-C in group 3 decreased significantly (P<0.05), but there were no significant difference from those of group 1 (P>0.05).The mRNA expression levels of FADS1, SCD1 and CYP2C45 in group 3 decreased significantly compared with group 1 (P<0.05), but there were no significant difference between groups 1 and 3 (P>0.05).In summary, this study demonstrated the recoverability of goose fatty liver at different layers, and thus laid a foundation for further investigation on the recovery or protective mechanism of goose fatty liver and found the solution to resolve the problems related to animal fatty liver.     

Effect of Supplementing Alfalfa Powder to Diet on Growth Performance and Meat Quality of Goose

The experiment was aimed to investigate the effects of dietary alfalfa powder on the growth performance,body size,slaughter performance,organ index and meat quality of Siji geese.A total of 256 15-day-old geese (half male and half female) with similar body weight were randomly divided into four groups with 4 replicates of 16 geese each.The geese in control group were fed with corn-soybean meal-based diet (control diet),and geese in the experimental groups were fed the basal diet replaced with 10%,20% and 30% alfalfa powder,respectively.The results showed that,compared with the control group,dietary alfalfa powder supplementation had no significant effect on the average daily intake,average daily gain,feed conversion ratio,body oblique length,keel length,shin circumference,semi diving length,chest width and shin length (P>0.05),and also had no effect on the carcass ratio,half-eviscerated carcass ratio and pectoral muscle ratio (P>0.05).However,dietary 20% and 30% alfalfa powder supplementation significantly increased the chest depth (P<0.05),dietary 30% alfalfa powder significantly decreased the full-eviscerated carcass ratio (P<0.05),and dietary 10% alfalfa powder significantly increased the leg muscle ratio (P<0.05) of geese.In addition,dietary alfalfa powder significantly decreased the abdominal fat ratio (P<0.05),raised the growth index of liver,jejunum,ileum,and cecum (P<0.05),and increased the water loss rate of pectoral muscle and leg muscle (P<0.05) compared with the control group.Dietary 10% and 30% alfalfa powder significantly increased duodenal growth index (P<0.05) of geese.In conclusion,dietary alfalfa powder supplementation might improve the slaughter performance (increase chest depth and leg muscle ratio,reduce abdominal fat rate) and organ growth index (increase the growth index of liver,duodenum,jejunum,ileum and cecum).However,dietary alfalfa powder increased water loss rates in pectoral muscle and leg muscle,and 30% alfalfa powder reduced the full-eviscerated carcass ratio of geese.The appropriate supplementation level of alfalfa powder was recommended at 10% in the present study.     

肥肝鹅恢复期血液生化指标、肝脏常规营养成分及脂代谢相关基因表达水平的变化研究

试验旨在研究朗德鹅填饲形成肥肝及恢复后其体重、肝脏重、腹脂重、常规营养成分、血液生化指标和肝脏中与脂代谢相关基因的表达变化情况,为进一步阐明鹅肥肝的恢复或保护机制提供依据。将18只70日龄朗德鹅随机分为3组(每组6只):组1为对照组,用玉米饲料进行常规饲喂;组2为填饲组,填饲玉米饲料19 d;组3为填饲19 d后再用玉米饲料常规饲养20 d进行肝脏恢复。结果显示,与组2相比,组3鹅体重、肝脏重均极显著降低(P<0.01),而腹脂重下降不显著(P>0.05);与组2相比,组3肝脏水分、灰分和粗蛋白质均显著上升(P<0.05),而粗脂肪含量显著下降(P<0.05),但与组1相比,除水分外,各项指标均无显著变化(P>0.05);与组2相比,组3血浆中谷丙转氨酶(ALT)、谷草转氨酶(AST)、甘油三酯(TG)和高密度脂蛋白胆固醇(HDL-C)浓度与组2相比均显著下降(P<0.05),但与组1相比,均无显著差异(P>0.05);与组2相比,组3肝脏中脂肪酸脱氢酶(FADS1)、硬脂酰辅酶A去饱和酶(SCD1)和细胞色素P450 2C45(CYP2C45)基因的表达量均显著下降(P<0.05),但与组1相比均无显著变化(P>0.05)。综上所述,本研究从不同层面揭示了鹅肥肝的可逆性,为深入研究鹅肥肝的恢复或保护机制,促进动物脂肪肝问题的解决奠定了基础。     

Effect of swine weaning age on body fat and lipogenic activity in liver and adipose tissue

Two experiments were conducted to evaluate the effects of weaning swine at 2 or 5 wk of age on postweaning performance and fat metabolism. In the first experiment, 52 pigs were weaned at 2 or 5 wk of age with body weights determined from birth to 8 wk. The early weaned group was fed a 20% protein corn-soybean meal-oat diet containing 25% dried whey from 2 to 5 wk while both groups were fed a 20% protein cereal grain-based diet from 5 to 8 wk of age. In a second experiment, a total of 90 pigs weaned at similar ages and fed the same diet sequences were killed at weekly intervals from 2 to 8 wk of age to evaluate body fat content and lipogenesis in liver and adipose tissue. Lipogenic capacity was measured by incorporation of acetate-1 14C into the total lipid fraction in liver slices and adipose tissue minces or by monitoring liver ATP citrate lyase activity. The results demonstrate that pigs weaned at 2 wk experience a slower postweaning growth rate with lower empty body weights than those either concurrently nursing the dam or weaned at 5 wk of age. Both groups had similar body weights from 6 to 8 wk of age. The body fat content of nursing pigs increased from 2 to 5 wk of age. Pigs weaned at 2 wk lost approximately 25% of their body fat the first week postweaning while later-weaned pigs did not lose body fat postweaning. Body fat composition of both groups was similar by 8 wk of age. Lipogenic activity was higher in liver than in adipose tissue from 2 to 5 wk of age and remained relatively constant throughout the trial. Adipose tissue lipogenic activity was lower in the nursing pig but increased dramatically at 5 wk in the early-weaned group and 7 wk of age in the late weaned group. These results suggest that weaning age can affect postweaning body fat composition and that adipose contributes a greater lipogenic capacity than liver tissue as the pig matures.     

饲粮不同比例青贮玉米对仔鹅生长性能、屠宰性能、肉品质及血清生化指标的影响

本试验旨在研究饲粮中添加不同比例全株青贮玉米对仔鹅生长性能、屠宰性能、肉品质及血清生化指标的影响,为全株青贮玉米在肉鹅养殖上的应用提供依据。试验选取健康、平均体重为982～985 g的28日龄三花鹅280只,随机分为4组,每组7个重复,每个重复10只仔鹅。对照组饲喂基础饲粮,试验组分别饲喂添加8%、16%、24%全株青贮玉米的试验饲粮,试验期为42 d。记录28、42、56、70日龄时鹅的体重（BW）和耗料量,计算平均日增重（ADG）、平均日采食量（ADFI）及料重比（F/G）; 70日龄时,每个重复选择2只接近平均体重的仔鹅屠宰,测定屠宰性能、肉品质和血清生化指标。结果表明：与对照组相比,在28～42日龄时,16%试验组的仔鹅ADG和ADFI显著升高（P<0.05）;在42～56日龄时,8%试验组的仔鹅ADFI显著升高（P<0.05）;在56～70日龄时,试验组的仔鹅ADG、ADFI和F/G均无显著差异（P>0.05）;28～70日龄的ADG和添加水平呈二次曲线关系（P<0.05）,达最高ADG水平的添加量为9.01%。与对照组相比,70日龄时,24%试验组的仔鹅体重显著降低（P<0.05）;各试验组的全净膛率和屠宰率显著降低（P<0.05）;屠宰率和添加水平呈二次曲线关系（P<0.05）,达最低屠宰率的添加水平为14.93%;各试验组仔鹅的肉品质无显著差异（P>0.05）。与对照组相比,8%试验组的仔鹅的血清甘油三酯含量显著降低（P<0.05）。综上所述,在本试验条件下,适量添加全株青贮玉米可提高仔鹅的生长性能,降低血清中的甘油三酯含量,对肉品质无显著影响,对屠宰性能有一定的负面影响,根据饲粮中添加全株青贮玉米的水平对ADG的最高限量和对屠宰性能的最低限量,建议在饲粮中的添加水平为9.01%～14.93%。