Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on lipid content and palatability in beef cattle

Thirty-six Angus x Hereford heifers were used in a 3 x 2 factorial (3 dietary treatments; 2 supplementation times) to examine the effect of dietary lipid supplementation on lipid oxidation, lipid composition, and palatability of ribeye steaks and ground beef. Lipid was supplied in the diets as corn oil or a partially rumen-protected CLA salt for 2 specific treatment periods of the final 32 or 60 d on feed, corresponding to a total time on feed of 89 or 118 d. After an initial 56-d feeding period (basal diet), the heifers were fed 1 of 3 dietary treatments (DM basis): 1) a basal diet containing 88% concentrate and 12% grass hay (CON), 2) the basal diet plus 4% corn oil (OIL), or 3) the basal diet plus 2% partially rumen-protected CLA (RPCLA) containing 31% CLA. Heifers were randomly allotted to dietary treatments at the initiation of the study and fed individually. At 48 h postmortem, the right forequarter of each carcass was fabricated into retail cuts. Steaks (2.54-cm thick) were obtained from the posterior end of the ribeye roll (NAMP 112), and beef trim was ground for all subsequent analyses. Dietary treatment did not affect (P > 0.05) lipid oxidation in ground beef or ribeye steaks. Total trans-octadecenoate fat and trans-10 octadecenoic acid content in ribeye steaks increased (P < 0.05) with RPCLA compared with CON. Total CLA and the cis-9 trans-11 isomer of CLA contents in ribeye steaks were unchanged (P > 0.05) by lipid supplementation. In ground beef, RPCLA supplementation increased (P < 0.05) the amount of trans fat and trans-10 octadecenoic acid compared with CON or OIL; supplementation of RPCLA increased (P < 0.05) the amount of CLA cis-9 trans-11 isomer and total CLA. Lipid supplementation did not alter (P > 0.05) off-flavor ratings in ground beef or ribeye steaks. Supplementation of corn oil increased (P < 0.05) total PUFA content of ribeye steaks compared with CON and RPCLA. Dietary RPCLA supplementation increased the amount of trans fat per serving (85.5 g, broiled) by 110 and 88% in ribeye steak and ground beef, respectively, and CLA cis-9 trans-11 by 58% in ground beef compared with CON. Supplementing OIL or RPCLA resulted in minimal changes in lipid oxidation and sensory attributes of steaks and ground beef.     

Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on fatty acid composition of adipose tissues in beef cattle

Thirty-six Angus x Hereford heifers (365 +/- 60 kg) were used to determine the effects of supplemental dietary lipid sources on fatty acid composition of i.m., perianal (p.a.), and s.c. lipid depots. Lipid was supplied to diets as either corn oil or a rumen-protected conjugated linoleic acid (CLA) salt for two specific treatment periods of either the final 32 or 60 d on feed. Following an initial 56-d feeding period, heifers were fed one of three dietary treatments (DM basis): 1) basal diet containing 88% concentrate and 12% grass hay (CON), 2) basal diet plus 4% corn oil (OIL), or 3) basal diet plus 2% rumen-protected CLA salt (RPCLA) containing 31% CLA. The trans-10, cis-12 CLA concentration was greatest (P < 0.05) for heifers fed RPCLA and OIL diets and least (P < 0.05) for CON, regardless of time on dietary treatment. Heifers fed supplemental RPCLA had greater (P < 0.05) total CLA content than either CON- or OIL-fed heifers. Adipose tissue concentration of trans-11 vaccenic acid (TVA) was less (P < 0.05) for CON than OIL or RPCLA, which did not differ (P > 0.05). Percentages of C18:1 trans-10 were least (P < 0.05) in i.m. lipid compared with p.a. and s.c., which did not differ (P > 0.05). Following 60 d of lipid supplementation, heifers fed OIL and RPCLA had lower (P < 0.05) concentrations of oleic acid and total monounsaturated fatty acids (MUFA) compared with CON. The ratio of cis-9, trans-11 CLA:TVA was higher (P < 0.05) for heifers fed 60 vs. 32 d, but did not differ (P > 0.05) between adipose depots. Feeding OIL increased (P < 0.05) adipose concentration of C18:2 fatty acid, whereas feeding RPCLA increased (P < 0.05) total CLA isomers by 22%. Intramuscular lipid contained the lowest (P < 0.05) percentage of cis-9, trans-11 CLA, total CLA, C18:1 cis-9, C18:1 trans-10, and TVA. Total CLA and cis-9, trans-11 CLA isomers were increased (P < 0.05) in p.a. and s.c. adipose depots, whereas i.m. adipose tissue contained increased (P < 0.05) amounts of total PUFA. Results from this study indicate that short-term lipid supplementation to feedlot cattle can increase adipose tissue CLA concentrations, but only marginally (8.3 to 17.5%). Moreover, observed decreases in oleic acid and total MUFA concentrations of adipose tissues from heifers fed rumen-protected CLA or corn oil suggest that lipid supplementation may decrease delta9 desaturase activity in adipose tissues, which in turn would lower the conversion of TVA to cis-9, trans-11 CLA isomer.     

Influence of a rumen-protected conjugated linoleic acid mixture on carcass traits and meat quality in young Simmental heifers

The aim of the present study was to investigate the influence of feeding rumen-protected CLA during the early growing period on physical and chemical beef properties in young Simmental heifers. A total of 36 heifers (5 mo old; initial BW 185 ± 21 kg) were fed 250 g of different rumen-protected fats daily for 16 wk in 1 of 3 treatment groups: 250 g of a CLA-free control fat; 100 g of a CLA fat containing 2.4% of cis-9,trans-11 CLA and 2.1% of trans-10,cis-12 CLA and 150 g control fat; or 250 g of the CLA fat. Heifer growth performance variables as well as carcass weight, classification (conformation and fatness), and weights of organs and fat depots were not affected (P > 0.05) by CLA supplementation. Concentration of trans-10,cis-12 CLA in tissues (LM and subcutaneous fat) was dose-dependently increased (P < 0.01) by CLA supplementation, whereas that of cis-9,trans-11 CLA in these tissues did not differ (P > 0.05) between groups. The ratio of SFA to MUFA was increased (P < 0.01) in tissues of CLA-fed heifers compared with control heifers. Concentration of α-tocopherol in LM was greater (P = 0.01) in heifers of the 2 CLA groups than in control heifers. Other quality characteristics such as drip loss during storage, cooking loss, intramuscular fat content, and color variables in LM did not differ (P > 0.05) between groups. In conclusion, the present study demonstrates that feeding rumen-protected CLA during the early growing period changes tissue fatty acid composition but does not influence beef quality variables. Performance variables and carcass traits in young heifers, unlike in pigs and laboratory animals, are not influenced by CLA feeding.     

瘤胃保护共轭亚油酸和亚油酸对奶牛产奶性能的影响

选择健康、泌乳月份与产奶量相近的多胎荷斯坦泌乳牛20头,随机分成5组,每组4头,研究日粮中添加商业来源的瘤胃保护共轭亚油酸钙盐(Ca-CLA)同时添加自然来源亚油酸(葵花油)对奶牛生产性能的影响。试验期为52d。对照组基础日粮为60%粗饲料(苜蓿、羊草、青贮)和40%精料(以DM为基础),处理组在对照组日粮基础上分别添加Ca-CLA100g/d·头(CLA)、葵花油350g/d·头(Sunf);Ca-CLA100g/d·头 葵花油350g/d·头(CLA Sunf),Ca-CLA50g/d·头 葵花油175g/d·头(1/2CLA 1/2Sunf)。结果表明:在奶牛日粮中,单独添加自然来源亚油酸产奶量较对照组差异不显著(P>0.05),而单独添加共轭亚油酸钙盐或与自然来源亚油酸高低不同剂量添加产奶量较对照组都分别显著提高2.20%、9.95%、11.16%,无论单独添加自然来源亚油酸或Ca-CLA或二者以高低不同剂量同时添加,牛奶的乳脂率较对照组都分别显著降低15.0%,6.24%,21.74%,14.35%。总之,奶牛日粮中同时添加Ca-CLA和自然来源亚油酸能显著提高产奶量,降低乳脂率,并且,减少Ca-CLA的添加量同时添加自然来源亚油酸可以达到高剂量添加Ca-CLA相同的效果。     

日粮添加共轭亚油酸钙盐和葵花油对奶牛产奶性能及饲料消化率的影响

试验研究了奶牛日粮中添加过瘤胃共轭亚油酸(Ca-CLA),同时添加葵花油对奶牛生产性能和饲料利用率的影响。选择健康、泌乳月份与产奶量相近的多胎荷斯坦泌乳牛20头,随机分成5组,每组4头。对照组(A组)基础日粮为60%粗饲料(苜蓿、羊草、青贮)和40%精料(以DM为基础),处理组在对照组日粮基础上每天每头牛分别添加Ca-CLA100g(B组)、葵花油350g(C组)、Ca-CLA100g+葵花油350g(D组)、Ca-CLA50g+葵花油175g(E组)。试验共进行52d。结果表明:C组产奶量较对照组差异不显著(P>0.05),B、D、E组产奶量较对照组都分别显著提高2.20%、9.95%、11.16%(P<0.05);B、C、D、E组牛奶的乳脂率较对照组都分别显著降低15.00%、6.74%、21.74%、14.35%(P<0.05)。与对照组相比,B组显著提高饲料中EE、CP、NDF、ADF消化率;C组除脂肪外其它营养成分消化率有降低的趋势但差异不显著;D、E组除脂肪消化率显著提高外,其它营养成分消化率差异不显著。     

Effect of feeding rumen-protected conjugated linoleic acid on carcass characteristics and fatty acid composition of sheep tissues

Two experiments were conducted to determine the effectiveness of a rumen-protected CLA (pCLA) supplement and the impact of feeding this pCLA on carcass characteristics and tissue fatty acid composition of lambs. In Exp. 1, a CLA-80 preparation (80% pure CLA; contained similar proportions of cis-9, trans-11, and trans-10, cis-12 CLA), protected against rumen degradation, was fed to sheep, and the proportion of CLA reaching the duodenum was determined. A 3 x 3 Latin square design was used with 3 diets (1.4 kg of concentrate-based control diet, the same control diet plus 22 g of CLA-80, or the same control diet plus 110 g of pCLA/d), 3 feeding periods, and 3 rumen and duodenally cannulated sheep (Mule x Charolais males, 10 mo of age, BW 55.3 +/- 1.8 kg). After 7 d of feeding, sheep were ruminally infused with chromium EDTA and Yb acetate for 7 d, after which samples of duodenal digesta were collected every 6 h for 48 h to determine the quantity of CLA reaching the small intestine each day. The amounts of CLA cis-9, trans-11 and trans-10, cis-12, and combined isomers, flowing through the duodenum each day were greater (P = 0.01) in sheep fed pCLA. Approximately 65% of the pCLA avoided rumen biohydrogenation, with the ratio of the 2 main isomers remaining similar. In Exp. 2, 36 Mule x Charolais ewe lambs (approximately 13-wk old, average initial BW 29.3 kg) were fed 3 levels of the pCLA or Megalac, which were fed to provide an equivalent energy content at each pCLA level. Lambs were randomly assigned to 1 of 7 treatment groups, which were fed for 10 wk to achieve a growth rate of 180 g/d. Treatments included the basal diet and the basal diet plus 25, 50, or 100 g of pCLA/kg of diet or the equivalent amount of Megalac. In liver (P < 0.001) and all adipose tissue depots studied, the proportions of both CLA isomers increased (P = 0.02) with the amount of pCLA fed but were not altered with increasing of Megalac. Although there was no effect of treatment on cis-9, trans-11 CLA content, accumulation (P < 0.001) in the LM with increasing of pCLA supplementation was observed for the trans-10, cis-12 isomer. Although tissues had been enriched with CLA, there was no evidence of a reduction in adipose tissue or an increase in muscle mass in these sheep. However, an effect of pCLA on tissue fatty acid composition was consistent with an inhibition of stearoyl-CoA desaturase.     

共轭亚油酸对北京油鸡肉品质及血清leptin和脂蛋白脂酶的影响

选用1日龄北京油鸡公雏360只,随机分成5个处理,每个处理6个重复,每个重复12只鸡,饲喂玉米豆粕型饲料基础日粮,添加0、0.25%、0.5%、1%、2%共轭亚油酸(CLA),用以研究CLA对北京油鸡脂类代谢和肉质性状的长期影响,试验期18周。结果表明:饲粮CLA提高了饲料利用率(P<0.05),显著性地降低了北京油鸡腹脂率和血清中脂蛋白脂酶(LPL)、leptin,显著增加了肌内脂肪的含量(P<0.05),但对pH值和肉色无显著性影响(P>0.05)。     

日粮共轭亚油酸对黄羽肉鸡生长性能及血清中瘦素和脂联素的影响

选用60只1日龄黄羽肉鸡,研究共轭亚油酸(CLA)对其生长性能、腹脂沉积的影响。结果显示,日粮中添加CLA可显著提高49日龄黄羽肉鸡腿肌重(P<0.05),显著降低母鸡的腹脂沉积(P<0.05),但对母鸡的体增重有抑制作用(P<0.05),且能提高血清中瘦素水平(P<0.05)。     

Duration of feeding conjugated linoleic acid influences growth performance, carcass traits, and meat quality of finishing barrows

Conjugated linoleic acid (CLA) was fed to growing-finishing barrows (n = 92) at 0.75% of the diet. A commercial CLA preparation (CLA 60) containing 60% CLA isomers was included at 1.25% to provide 0.75% CLA in the diet. The inclusion of CLA in diets was initiated at various BW and fed until slaughter. Growth, carcass, meat quality, physical, chemical, and sensory data were collected and analyzed. Treatments T1, T2, T3, and T4 included the last 0, 29, 56 and 87 kg, respectively, of weight gain before slaughter. Average daily gain and feed intake were not affected (P > or = 0.06) by CLA, but gain:feed responded quadratically (P = 0.05), over the entire BW gain (28 to 115 kg) with pigs of T2 and T3 having the greatest gain:feed. Loin muscle area increased (P = 0.01) linearly with increasing weight gain while fed CLA, and 10th rib, first rib, and last rib fat depth decreased (P < or = 0.05) linearly. Subjective quality measures on loin muscles increased linearly for marbling (P < 0.05) and tended to increase for firmness (P = 0.07) with increasing weight gain while barrows were fed CLA. Objective Hunter color values for loin chops from T1 and T4 were not different for L* (P = 0.12) or a* (P = 0.08) values but were higher (P < 0.05) for b* values with CLA feeding. Lipid oxidation values of loin muscle tissue were lower (P < 0.05) for pigs fed CLA (T1 vs T4). Increasing the period of weight gain while feeding CLA linearly increased (P < 0.01) saturated fatty acids and CLA isomers in loin tissue and linearly increased (P < 0.01) saturated fatty acids and CLA isomers in subcutaneous adipose tissue. Sensory panel characteristics of loin chops were not changed (P > 0.05) by feeding CLA. Increased gain:feed, increased loin muscle area, decreased fat depth, and improvements in marbling and firmness with CLA feeding could result in improved profitability of pork production systems.     

黄曲霉毒素B1分解酶对肉牛生长性能、胴体品质及毒素组织残留的影响

选取30头体质量344kg左右健康西门塔尔杂交牛,随机分为3组:对照组,饲喂基础饲粮;试验Ⅰ组和Ⅱ组分别在基础饲粮基础上添加0.05%和0.10%的黄曲霉毒素B1分解酶,试验期90d。结果表明:各组之间生长性能、胴体指标、血液和肝脏生化指标差异不显著(P0.05);添加黄曲霉毒素B1分解酶显著降低了毒素在肝脏(P0.01)和肾脏(P0.05)中的残留。试验Ⅰ、Ⅱ组肝脏黄曲霉毒素的B1残留量分别比对照组下降了44.87%(P0.01)和49.15%(P0.01);试验Ⅰ、Ⅱ组肾脏中黄曲霉毒素的B1残留量分别比对照组下降了32.20%(P0.05)和33.90%(P0.05)。由此可知,肉牛饲料中添加黄曲霉毒素B1分解酶可降低毒素在组织中的残留。     

共轭亚油酸对肉仔鸡体组成和肉品品质的影响

本试验旨在探讨日粮添加共轭亚油酸(CLA)对肉仔鸡体组成和肉品品质的影响。240只1日龄肉仔鸡随机分配到4个日粮处理组(0%、0.25%、0.5%和1%CLA),每个处理6个重复,每个重复10只鸡。试验结果表明:42d时,0.5%和1%CLA组肉仔鸡胸肌率显著高于对照组(P<0.05),1%CLA组肉仔鸡42d腿肌率显著高于对照组,肉仔鸡的腹脂率在各处理之间没有显著差异(P>0.05),1%CLA组肉仔鸡胸肌粗蛋白质粗脂肪比显著高于对照组(P<0.05)。0.5%、1%CLA组肉仔鸡胸肌滴水损失和丙二醛(MDA)含量显著降低(P<0.05)。试验结果表明,CLA可改善肉仔鸡屠体性状,增加鸡肉系水力和延长货架存放时间。     

共轭亚油酸对小鼠血清瘦素、内脂素水平及生殖的影响

本试验旨在探讨共轭亚油酸对小鼠生殖的影响及其机理。购入60只6~7周龄的KM雌性小鼠,随机分为2组。对照组饲喂添加了1.5%花生油的繁殖颗粒料,试验组饲喂添加了1.5%花生油和1.5%共轭亚油酸的繁殖颗粒料。酶联免疫法测定不同生殖周期血清瘦素和内脂素浓度,常规石蜡切片法制备卵巢切片,观察卵巢的组织学结构并计数次级卵泡数量。每组各6只妊娠后饲养至产仔。结果显示:共轭亚油酸极显著降低了间情期、发情期、妊娠5d小鼠的血清瘦素浓度(P0.01),显著降低了妊娠9d瘦素浓度(P0.05);共轭亚油酸极显著降低了间情期、发情期、妊娠9d的血清内脂素浓度(P0.01),显著降低了妊娠5d时血清内脂素浓度(P0.05);共轭亚油酸极显著增加发情期次级卵泡的数量和产仔数(P0.01)。由此可见,共轭亚油酸可能通过调节血清瘦素和内脂素水平,增加发情期次级卵泡数量和胚胎数量,提高小鼠的生殖能力。     

共轭亚油酸对肉鸭生产性能与屠体性状的影响研究

本试验通过添加不同剂量的共轭亚油酸来探讨其对肉鸭的生产性能和屠体性状的影响.选用7日龄健康、体重相近的天府肉鸭84只(公母各半)(P>0.05),按单因素完全随机设计分4个处理,每个处理3个重复,共21只鸭,试验期35 d.共轭亚油酸在基础日粮上分别添加0%、1%、2%和3.5%.试验结果表明:①在肉鸭的生长期内,适量添加共轭亚油酸能提高肉鸭的平均重和饲料转化率.在共轭亚油酸添加水平达2%时,促进了肉鸭生长,而3.5%水平时,却抑制了肉鸭的增重.②共轭亚油酸具有一定的营养重分配作用,提高了肉鸭的胸肌率、腿肌率,降低了腹脂率.在胸肌率方面,Ⅱ组、Ⅲ组、Ⅳ组比Ⅰ组(对照组)提高了0.5%(P>0.05)、1.79%(P<0.05)、2.5%(P<0.01);在腿肌率方面,Ⅱ组、Ⅲ组、Ⅳ组比Ⅰ组提高了1.1%(P>0.05)、1.7%(P<0.05)、2.7%(P<0.05); 在腹脂率方面,Ⅱ组、Ⅲ组、Ⅳ组比Ⅰ组降低了8.9%(P>0.05)、15.7%(P<0.05)、18.6%(P<0.05).     

非常规饲料原料日粮对肉牛生长性能、胴体性状、肉品质及经济效益的影响

文章旨在评估不同非常规饲料原料替代浓缩料对肉牛生长性能、胴体性状及肉品质的影响。试验选择初始体重为（291.69±5.7）kg的肉牛80头,随机分为4组,每组20头,每头牛为1个重复。对照组肉牛在8周试验期每天自由采食水稻秸秆粗饲料并补充基础浓缩料,处理组肉牛自由采食水稻秸秆粗饲料并分别补充用8%米糠、亚麻籽和葵花粕替代基础浓缩料混合物。结果：与米糠组相比,对照组和亚麻籽组肉牛的平均日增重分别显著提高10.74%和12.40%（P＜0.05）,同时米糠组肉牛的料重比较对照组和亚麻籽组分别显著提高11.69%和15.52%（P＜0.05）。亚麻籽组肉牛的背膘厚度较对照组和米糠组分别显著提高7.84%和8.65%（P＜0.05）。对照组肉牛眼肌C14：0脂肪酸含量显著低于处理组（P＜0.05）,而米糠组肉牛眼肌饱和脂肪酸含量较对照组显著提高16.55%（P＜0.05）,单不饱和脂肪酸含量显著降低11.95%（P＜0.05）。亚麻籽和葵花粕组眼肌中蛋氨酸含量较对照组和米糠组分别显著提高168%、179.17%和154%、164.58%（P＜0.05）。结论：在本研究条件下,用8%亚麻籽替代浓缩料饲喂肉牛可以提高肌肉蛋氨酸含量,对肉牛生长表现及肌肉脂肪酸组成无负面影响。 [关键词]非常规原料|肉牛|生长性能|胴体性状|肉品质     

CLA发酵豆粕对羔羊生长性能、胴体性能和肉品质的影响

选择120只健康、体重(11.77±0.70)kg的黄淮白山羊公羔,随机分为4组,每组6个重复,每个重复5只。对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组分别用2.5%、5.0%和7.5%CLA发酵豆粕等量替代基础日粮中普通豆粕,预饲期为10 d,正式试验期为30 d。结果表明:CLA发酵豆粕对黄淮白山羊公羔的生长性能均无显著影响(P>0.05);试验Ⅲ组的胴体骨重显著高于对照组和试验Ⅰ组(P<0.05),试验Ⅲ组的骨肉比极显著高于对照组和试验Ⅰ组(P<0.01),其他胴体性能无显著差异(P>0.05);CLA发酵豆粕对黄淮白山羊公羔的肉品质而及羔羊肌肉的化学指标均无显著影响(P>0.05)。     

Effects of rumen-protected oil supplementation on finishing grazing beef cattle

Tropical Animal Health and Production - The objective of this study was to evaluate the effects of rumen-protected oil (soybean and palm oil) in supplements for beef cattle during the fattening...     

青贮饲用高粱对肉牛屠宰性能、胴体品质的影响

为探究青贮饲用高粱对肉牛屠宰性能、胴体品质的影响,综合考虑各种青贮饲用高粱的营养搭配是否满足肉牛营养需要,以期推动中国现代肉牛经济发展。研究以西门塔尔三代阉牛为试验牛,以BJ0603青贮饲料作为基础饲粮。饲喂试验结束后,每个日粮处理组挑选3头牛进行屠宰分割,测定屠宰性能及胴体品质。结果表明,不同比例的青贮高粱和青贮玉米不仅会影响肉牛的采食量和日增重,还会间接影响肉牛的产肉性能。随着日粮中青贮饲用高粱比例的增加,肉牛的采食量降低,能量摄入不足,影响机体内脂肪的正常沉积,降低了肉的嫩度。但对牛肉常规营养成分无显著影响,对其肉色影响显著。     

Effects of high-oil corn on feedlot performance, carcass characteristics, fatty acid profiles, beef palatability, and retail case life traits of beef top loin steaks

Our objective was to compare the effects of feeding steam-flaked, high-oil corn with normal steam-flaked corn to which yellow grease was added to equalize dietary fat on performance and carcass characteristics of finishing beef steers, and palatability, retail case life, and fatty acid composition of strip loins. Angus steers (n = 120; initial BW = 288 kg) were allotted to dietary treatments consisting of 1) normal mill-run, steam-flaked corn plus added fat (NMR) or 2) high-oil, steam-flaked corn (HOC) and assigned randomly to pens (12 pens/treatment with 5 steers/pen). Performance (ADG, DMI, and G:F) was measured over time, and cattle were shipped to a commercial abattoir for collection of carcass data after 165 d on feed. Carcass data were collected at 48 h postmortem on all carcasses, and 2 carcasses from each pen were selected randomly for collection of strip loins (IMPS #180A). At 14 d postmortem, 4 steaks (2.54 cm thick) were removed for retail display, trained sensory panel analysis, Warner-Bratzler shear force determination, and fatty acid analysis. Daily BW gain was greater (P = 0.03) and G:F was increased 8.4% (P = 0.01) for steers fed NMR compared with HOC, but DMI was not affected (P > 0.10) by treatment. No treatment differences were observed (P > 0.10) for HCW, 12th-rib fat, KPH, and yield grade. Marbling scores were greater (P = 0.01) for NMR than for HOC, and LM area tended (P = 0.07) to be greater in NMR than in HOC carcasses. The proportion of carcasses grading USDA Choice did not differ (P = 0.77) between treatments, but a greater (P = 0.04) proportion of carcasses graded in the upper two-thirds of Choice for NMR vs. HOC. Trained sensory panel traits and Warner-Bratzler shear force values did not differ between treatments (P > 0.10), and no differences (P > 0.10) were detected for purge loss or fatty acid composition. Overall, ADG and G:F were less and marbling score was decreased, but there were no differences between treatments in beef palatability, retail case life, or concentrations of fatty acids in strip loins.     

Effects of steam-flaked sorghum grain or corn and supplemental fat on feedlot performance, carcass traits, longissimus composition, and sensory properties of steers.

One hundred forty British x Exotic crossbred, yearling steers (370 kg) were used in a 2 x 2 factorial experiment to evaluate main effects and the interaction of grain type (steam-flaked sorghum grain [SFSG] or steam-flaked corn [SFC]) and level of supplemental far (0 or 4% yellow grease [YG]) on feedlot performance, diet NE concentration, carcass traits, and chemical composition and sensory properties of longissimus muscle. Steer performance and estimated dietary NEm and NEg values were not different between SFSG and SFC. Supplemental YG improved (P less than or equal to .05) gain/feed and estimated NEm and NEg of both SFSG and SFC diets. Compared with steers fed SFSG, steers fed SFC had a more yellow (P less than .05) subcutaneous fat color. Supplemental YG had an additive effect (P less than .025) on yellow color of subcutaneous fat but improved (P less than .08) the lean color of longissimus muscle. Grain type or supplemental YG had no effect on sensory properties or mechanical shear of longissimus muscle. Longissimus muscle cholesterol content was elevated (P less than .05) by supplemental YG (.49 vs .52 mg/g of wet tissue for 0 vs 4% YG, respectively); however, the biological significance of this result is questionable. Similarly, effects of YG on increased (P less than .05) stearic acid concentration and a higher concentration (P less than .05) of linoleic acid measured in longissimus muscle of steers fed SFSG vs SFC were small in magnitude. These data indicate that under the conditions of this experiment, NE contents of SFSG and SFC were similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

日粮中添加植物油对延边黄牛牛肉中共轭亚油酸含量的影响

本研究通过在延边黄牛育肥牛日粮中添加不同水平的混合植物油,探讨植物油对延边黄牛牛肉中共轭亚油酸(CLA)含量的影响.试验采用单因子随机区组设计,选择体重相近的健康延边黄牛(公牛)16头,按体重随机分为4组,每组4头.对照组饲喂基础日粮,试验组在基础日粮中分别添加4%、5%、6%(以精料为基础)的混合植物油,试验期为88 d.混合植物油以豆油、红花油和葵花油.按55%、25%和20%的比例混合而成.试验结果表明:日粮添加4%、5%和6%植物油与对照组相比,牛肉中的共轭亚油酸(c9,t11)含量显著提高(P<0.05),4%、5%、6%植物油组分别比对照组提高了275%、287.5%、325%,并随植物油水平提高呈上升趋势;各试验组共轭亚油酸(t10,c12)含量均高于对照组,但差异不显著(P0.05);牛肉中亚油酸(C18∶2)和亚麻酸(C18∶3)含量极显著高于对照组(P<0.01),4%、5%、6%植物油组亚油酸含量分别比对照组提高了52.38%、41.74%、46.50%,亚麻酸含量分别比对照组提高了105.88%、47.06%、52.94%;油酸(C18∶1)含量.各试验组均高于对照组,但差异不显著(P0.05),随植物油添加水平的提高呈上升趋势;不饱和脂肪酸含量,各试验组均高于对照组,随植物油添加水平的提高呈上升趋势,其中6%植物油组与对照组差异显著(P<0.05);饱和脂肪酸含量各试验组均高于对照组但差异不显著(P0.05).