Compensatory growth response in pigs: effects on growth performance, composition of weight gain at carcass and muscle levels, and meat quality

A restriction/realimentation feeding strategy was applied to pigs to increase the age at market weight and final ADG, modify protein and lipid deposition rates at carcass and muscle levels, and thereby improve eating quality of the pork. A total of 126 Duroc x (Large White x Landrace) pigs (females and castrated males) were used. At the average BW of 30 kg, within litter and sex, pairs of littermates (blocked by BW) were randomly assigned to ad libitum (AL) feeding during growing (30 to 70 kg of BW) and finishing (70 to 110 kg of BW) periods (AL, n = 56), or restricted feeding at 65% of the ADFI of the AL pigs, on a BW basis, during the growing period and AL feeding during finishing (compensatory growth, CG; n = 56). In each feeding regimen, 15 pigs were slaughtered at 70 kg of BW, and 41 pigs were slaughtered at 110 kg of BW. Additionally, 14 pigs were slaughtered at 30 kg of BW to calculate tissue deposition rates. The CG pigs showed decreased ADG (-35%, P = 0.001) during growing but increased ADG (+13%, P = 0.001) during finishing (i.e., compensatory growth) due to greater (P = 0.001) ADFI and G:F. Hence, CG pigs were 19 d older at 110 kg of BW than AL pigs. The CG pigs were leaner at 70 kg of BW than AL (e.g., 11.7 vs. 13.5 mm of average backfat thickness for CG and AL pigs, respectively, P = 0.023), whereas the differences were reduced at 110 kg of BW (20.6 vs. 21.0 mm of average backfat thickness for CG and AL pigs, respectively, P = 0.536). At 70 kg of BW, intramuscular fat (IMF) content of LM did not differ between CG and AL pigs (1.25 vs. 1.49%, respectively, P = 0.118), whereas CG pigs had less IMF in LM at 110 kg of BW (2.19 vs. 2.53% for CG and AL pigs, respectively, P = 0.034). Feeding regimen influenced the composition of weight gain. From 30 to 70 kg of BW, feed restriction reduced (P = 0.001) lean and adipose tissue deposition at the carcass level and protein and lipid deposition at the muscle level. From 70 to 110 kg of BW, the CG feeding strategy increased (P = 0.016) deposition of adipose but not of lean tissue at the carcass level. However, lipid and protein deposition at the muscle level were not affected. Thus, realimentation promoted deposition of subcutaneous fat over IMF. Feeding regimen hardly affected technological meat quality at 110 kg of BW. The CG feeding strategy decreased (P = 0.014) the meat juiciness score in relation to the decreased IMF but did not influence other sensory traits. Elevated IMF content and improved pork quality might be achieved by modifying the onset or duration of the restriction and realimentation periods.     

胆囊收缩素主动免疫对猪生产性能、胴体品质及肉质的影响

为了研究胆囊收缩素(CCK-8)主动免疫对猪生产性能、胴体品质、肉质的影响,将12头体重为23.2±0.3kg的长荣猪随机分为2个处理,试验组和对照组,每个处理3个重复,每个重复2头猪,其中试验组猪注射CCK-8 人血清白蛋白(HSA),对照组猪则只注射HSA,测定猪的日采食量、日增重、料重比、屠宰率、胴体斜长、背膘厚、眼肌面积、pH、肉色评分、大理石纹、失水率、肌间脂肪等指标。试验期78d。整个试验期,与对照组相比,试验组的日增重低5.53%(P>0.05),日采食量高0.6%,料重比高6.64%(P>0.05),这表明,500μgCCK-8主动免疫有降低猪整个试验期生产性能的趋势,CCK-8免疫对猪胴体品质和肉质无显著影响,但对肉质有改善的趋势。     

Slaughterline records of various postmortem pathological lesions and their influence on carcass and meat quality in slaughtered pigs

The aim of this study was to identify the prevalence of pathological lesions in pigs from small‐scale farms and to determine associations between pathological lesions and hematological parameters, and carcass and meat quality in slaughtered pigs. The study was conducted on 625 pigs (~115 kg) originating from 20 small‐scale farms. Any signs of pneumonia, pleurisy, pericarditis, and liver milk spots were recorded as present or absent. Complete blood count was investigated. The following carcass quality parameters were measured: live, hot and cold carcass weights, cooling loss, dressing percentage, backfat thickness, and meatiness. Meat pH and temperature were measured 45 min postmortem. Of the 625 examined pigs, 41.8% had pneumonia, 23.5% pleurisy, 2.7% pericarditis, and 29.9% liver milk spots. The presence of pathological lesions in slaughtered pigs adversely affected hematological parameters, reduced live, hot and cold carcass weights, and meatiness and had deleterious effects on meat quality (higher pH_45min and higher prevalence of dark, firm and dry meat). In conclusion, this study showed a high prevalence of pathological lesions in slaughtered pigs, indicating serious health problems in smallholder pig production systems. The presence of single and, especially, multiple pathological lesions in slaughtered pigs negatively affected hematological parameters, and carcass and meat quality.     

Influence of a conjugated linoleic acid mixture on growth, organ weights, carcass traits and meat quality in growing pigs

Grain soybean meal diets, either with 2% of a conjugated linoleic acid (CLA) preparation or with 2% rapeseed oil (control), were tested in 2 × 40 pigs, Pietrain × (Landrace × Large White), each group with 20 female in the live weight range 23.5–117.0 kg and 20 male-castrated pigs in the live weight range 23.5–110.6 kg. The CLA-content of the preparation amounted to 54.0% cis / trans + trans / cis , 8.7% cis/cis and 32.7% trans / trans isomers. Daily weight gain, feed intake and feed : gain ratio were not influenced by the diets tested. The carcass lean increased significantly from 57.2% of the control group to 58.7% in the CLA group (p   < 0.05). The male-castrated showed a stronger CLA effect than the female pigs – not only was the carcass lean significantly increased by 2%, but backfat thickness was significantly decreased by 2.8 mm, i.e. minus 11% (as compared with barrows of the control). The meat of CLA-fed pigs had a higher conductivity. A CLA effect on further meat quality characteristics (pH 45 min post-mortem, impedance, colour criteria, intramuscular fat, drip loss, frying loss, shear force, sensory attributes) could not be detected. There were some significant correlations between the meat quality attributes.     

Effects of dietary soy isoflavones on growth, carcass traits, and meat quality in growing-finishing pigs

Two experiments were conducted to determine the effect of soy isoflavones on growth, meat quality, and carcass traits of growing-finishing pigs. In Exp. 1, 36 barrows (initial and final BW, 26 and 113 kg, respectively) were used and each treatment was replicated four times with three pigs each. The dietary treatments were 1) corn-soybean meal (C-SBM), 2) corn-soy protein concentrate (low isoflavones, C-SPC), or 3) C-SPC + isoflavones (isoflavone levels equal to those in C-SBM). Daily gain and ADFI were increased (P < 0.10) in pigs fed the C-SPC relative to pigs fed the C-SPC + isoflavone diet in the late finishing period; otherwise, growth performance was not affected (P > 0.10) by diet. Longissimus muscle area, 10th-rib fat depth, percentage muscling (National Pork Producers Council), 24-h pH and temperature, color, firmness-wetness, marbling, drip loss, and CIE L*, a*, and b* color values were not affected (P > 0.10) by diet. Dressing percentage, carcass length, weight and percentage of fat-free lean in ham and carcass, lean gain per day, lean:fat, and ham weight were increased (P < 0.10), and ham fat and percentage fat in ham and carcass were decreased (P < 0.10) in pigs fed the C-SPC + isoflavone diet compared with pigs fed the C-SPC diet. Pigs fed the C-SPC + isoflavone diet had similar (P > 0.10) carcass traits as pigs fed the C-SBM diet, except carcass length, percentage ham lean and thaw loss were greater (P < 0.10), and total ham fat was less (P < 0.10) in pigs fed the C-SPC + isoflavone diet. In Exp. 2, 60 gilts (initial and final BW, 31 and 116 kg, respectively) were used, and each treatment was replicated five times with four pigs per replicate. The treatments were 1) C-SBM, 2) C-SBM + isoflavone levels two times those in C-SBM, and 3) C-SBM + isoflavone levels five times those in C-SBM. Daily feed intake was linearly decreased (P < 0.10) in the growing phase and increased (P < 0.10) in the late finishing phases as isoflavone levels increased; otherwise, growth performance was not affected (P > 0.10) by diet. Diet did not affect (P > 0.10) carcass traits; however, CIE a* and b* color scores and drip loss were decreased (P < 0.06) as isoflavone levels increased. Soy isoflavones decreased fat and increased lean in barrows when fed within the dietary concentrations found in typical C-SBM diets but not when fed to gilts at concentrations above those present in C-SBM diets.     

Effect of carbohydrate source on growth performance, carcass traits, and meat quality of growing-finishing pigs

Two experiments were conducted to determine the effect of substituting a more available dietary carbohydrate (CHO) for portions of corn or fat in the diet on growth performance, carcass traits, meat quality, and serum or plasma metabolites in growing-finishing pigs. A three-phase feeding program was used with corn-soybean meal diets formulated to provide 105% of the Lys requirement for barrows or gilts gaining 325 g of lean daily in Exp. 1 or gilts gaining 350 g of lean daily in Exp. 2. Diets were isoenergetic within experiments. All other nutrients met or exceeded suggested requirements. In Exp. 1, pigs were allotted to three dietary treatments (0, 7.5, or 15.0% sucrose), with three replications of barrows and three replications of gilts, and with three or four pigs per replicate pen; average initial and final BW were 25.2 and 106.7 kg. In Exp. 2, gilts were allotted to two dietary treatments (waxy [high amylopectin] or nonwaxy [75% amylopectin and 25% amylose] corn as the grain source), with five replications of four gilts per replicate pen; average initial and final BW were 37.7 and 100.0 kg. In Exp. 1, ADG and gain:feed ratio increased linearly (P < 0.02) as dietary sucrose increased. Minolta color scores, a* and b*, and drip loss (P < 0.06) also increased linearly with added sucrose. In Exp. 2, ADG, carcass weight and length, and the Minolta a* value were greater for pigs fed waxy corn (P < 0.08) than for those fed nonwaxy corn. Feed intake, longissimus muscle area, 10th-rib and average backfat thickness, dressing percentage, fat-free lean, percentage of lean and muscling, lean gain per day, total fat, percentage fat, lean:fat ratio, serum or plasma metabolites (Exp. 1: serum urea N; Exp. 2: serum urea N, and plasma nonesterified fatty acids, triacylglycerols, total and high-density lipoprotein cholesterol, insulin, and total protein), pH of the longissimus muscle, and subjective muscle scores (color, firmness-wetness, and marbling) were not affected by diet in either experiment. In summary, increasing availability of dietary CHO in growing-finishing pig diets improved growth performance, but it did not affect carcass traits.     

Relationship between perilipin genes polymorphisms and growth,carcass and meat quality traits in pigs

The perilipins (PLIN) belong to a family of structural proteins that play a role regulating intracellular lipid storage and mobilization. Here, PLIN1 and PLIN2 have been evaluated as candidate genes for growth, carcass and meat quality traits in pigs. A sample of 607 Duroc pigs were genotyped for two single‐nucleotide polymorphisms, one in intron 2 of the PLIN1 gene (JN860199:g.173G>A) and the other at the 3′ untranslated region of the PLIN2 gene (GU461317:g.98G>A). Using a Bayesian approach, we have been able to find evidence of additive, dominant and epistatic associations of the PLIN1 and PLIN2 polymorphisms with early growth rate and carcass length. However, the major effects were produced by the dominant A allele at the PLIN2 polymorphism, which also affected the carcass lean weight. Thus, pigs carrying an additional copy of the A allele at the g.98G>A PLIN2 polymorphism had a probability of at least 98% of producing carcasses with heavier lean weight (+0.41 kg) and ham weight (+0.10 kg). The results obtained indicate that the PLIN2 polymorphism could be a useful marker for lean growth. In particular, it may help to reduce the undesired negative correlated response in lean weight to selection for increased intramuscular fat content, a common scenario in some Duroc lines involved in the production of high quality pork products.     

甜菜碱和B族维生素对商品猪生长性能及同体肉品质影响

许多研究表明,甜菜碱可以促进肥育猪生长,改善饲料利用率,降低背膘厚,减少胴体脂肪沉积,增大眼肌面积和提高瘦肉率。日粮中添加B族维生素,可     

非淀粉多糖酶对生长育肥猪生长性能、胴体性状和肉品质的影响

本研究主要通过生长育肥猪的饲养试验,观察日粮中添加非淀粉多糖酶(Non-Starch Polysaccharide Enzyme,NSP酶)对生长育肥猪生长性能、胴体性状和肉品质的影响。试验选择体质量约为40kg的杜长大三元杂交猪48头,公母各半。本试验随机分为2个处理,每个处理3个重复,每个重复8头猪,对照组饲喂基础日粮,NSP酶组饲喂基础日粮+0.6%NSP酶。结果表明:(1)生长性能方面,NSP酶组的平均日增重和平均日采食量均显著高于对照组(P<0.05),分别提高了9.8%和4.7%;NSP酶组的料重比显著低于对照组(P<0.05),降低了5.0%;(2)在胴体性状和背最长肌化学组成方面,NSP酶组眼肌面积比对照组显著提高(P<0.05),提高了9.8%;与对照组相比,滴水损失和剪切力2个指标分别降低了2.0%和14.6%,但在统计学上未达到显著水平(P>0.05)。结果显示,基础饲粮中添加NSP酶能有效提高生长育肥猪生长性能,并在一定程度上改善肉品质。     

烟台黑猪不同杂交组合猪肥育性能、胴体品质及肉质研究

研究测定了烟台黑猪与鲁育杜洛克、鲁育大约克和长白猪杂交商品猪的生长肥育性能、胴体品质及肉质。结果表明,大约克×烟黑组合日增重最高为717.37 g,料重比最低为2.97,与杜洛克×烟黑、长白×烟黑和烟黑×烟黑相比,日增重分别提高7.93%（P〉0.05）、16.22%（P〈0.05）和21.31%（P〈0.01）,料重比分别降低11.08%、3.88%、21.43%。4个组合的胴体性能及肉品质差异显著。其中,屠宰率以杜洛克×烟黑最高,比大约克×烟黑提高11.69%（P〈0.05）;眼肌面积也以杜洛克×烟黑最大,比烟黑×烟黑提高31.33%（P〈0.05）;瘦肉率以大约克×烟黑最高为60.24%,比烟黑×烟黑提高22.09%（P〈0.01）;大理石纹评分以烟黑×烟黑最高,其次是杜洛克×烟黑,分别比大约克×烟黑、长白×烟黑提高10.67%（P〉0.05）、38.02%（P〈0.05）和9.15%（P〉0.05）、36.12%（P〈0.05）;pH1以大约克×烟黑最高为6.66,其次是烟黑×烟黑组合为6.29,分别比杜洛克×烟黑、长白×烟黑提高14.63%（P〈0.01）、17.25%（P〈0.01）和8.26%（P〈0.01）、10.74%（P〈0.01）;失水率以杜洛克×烟黑最低,比长白×烟黑降低51.49%（P〈0.05）。4个组合的背最长肌氨基酸总量、鲜味氨基酸含量和必需氨基酸含量都以烟黑×烟黑组合最高,分别比大约克×烟黑和长白×烟黑提高10.07%（P〈0.01）和6.17%（P〈0.05）、9.55%（P〈0.01）和6.17%（P〈0.05）、11.18%（P〈0.01）和6.79%（P〈0.05）。背最长肌棕榈酸含量以杜洛克×烟黑最高,比大约克×烟黑提高10.59%（P〈0.05）;硬脂酸也以杜洛克×烟黑最高,分别比大约克×烟黑、长白×烟黑和烟黑×烟黑提高18.62%（P〈0.01）、20.5%（P〈0.01）和20.20%（P〈0.01）;油酸以烟黑×烟黑最高,比杜洛克×烟黑提高11.96%（P〈0.05）。     

营养水平对鲁农2号生长猪屠宰性能和肉品质的影响

试验选用108头鲁农2号生长猪(49.58±1.49)kg,随机区组,分为3个处理组,每处理4个重复,每重复(圈)9头猪,在保持日粮消化能/粗蛋白质比例不变的情况下,分为高、中、低3个营养水平组,研究日粮不同消化能和粗蛋白质水平对鲁农2号生长猪屠宰性能和肉品质的影响。试验分50～80 kg和80～100 kg两个体重阶段饲养,当试验猪平均体重达到100 kg时进行屠宰,测定屠宰性能和肉品质。结果表明:3个处理组的背膘厚、眼肌面积、后腿重、后腿比例、脂肪率、屠宰率和瘦肉率均差异不显著(P>0.05);除大理石纹外,3个处理组的肉品质差异也不显著(P>0.05)。这预示着低能量和粗蛋白质日粮饲喂鲁农2号生长猪可以获得与高能量粗蛋白质日粮相近的屠宰性能和肉品质。     

育肥方式对滇南小耳猪生长、胴体性能和肉质的影响及经济效益分析

为探讨不同育肥方式对滇南小耳猪生长、胴体性能、肉质和经济效益的影响,分规模养殖场标准化育肥(对照组)、农村吊架子育肥(试验Ⅰ组)和全放养加补饲(试验Ⅱ组)3种方式进行育肥试验,测定其胴体、肉质、肌肉化学成分、氨基酸成分,结果显示:试验Ⅰ组猪只的平均日增重、6~7肋间膘厚、三点均膘和肌肉粗脂肪含量分别比对照组降低17.96%、21.04%、15.36%和47.29%(P0.01),胆固醇含量降低43.60%(P0.05),胴体瘦肉率和肌肉甘氨酸含量分别提高8.82%和8.86%(P0.01),肌肉粗蛋白、氨基酸含量、必需氨基酸含量和呈味氨基酸含量分别提高7.78%、10.69%、9.74%和10.15%(P0.05);试验Ⅱ组猪只的平均日增重、胴体瘦肉率和肌肉粗脂肪含量分别降低37.71%、11.20%和47.29%(P0.01),胆固醇含量降低41.71%(P0.05),6~7肋间膘厚、三点均膘和肌肉甘氨酸含量分别提高14.75%、23.19%和16.46%(P0.01),肌肉粗蛋白含量、氨基酸总量、必需氨基酸含量和呈味氨基酸总量分别提高10.52%、14.22%、13.08%和13.75%(P0.05);对照组、试验Ⅰ组、试验Ⅱ组在各氨基酸含量上呈现依次递增的趋势(P0.05),对照组、试验Ⅰ组和试验Ⅱ组每头猪的经济效益分别为-109.86元/头、10.39元/头和99.54元/头。吊架子育肥和全放养加补饲育肥均可降低滇南小耳猪肌肉粗脂肪含量和胆固醇含量,提高熟肉率、肌肉粗蛋白含量、总氨基酸含量、必需氨基酸含量和呈味氨基酸含量,改善猪肉食用品质;虽降低了生长速度,延长了育肥时间,但减少了精料用量,反而可获较好的经济效益。     

小肽复合剂对育肥猪的生长性能及胴体和肉质性状的影响效应研究

试验旨在研究小肽复合剂对育肥猪生长性能、胴体性状及肉质性状的影响效果。将72头同批次健康的65日龄的(长×大)二元杂交商品猪随机分为试验组和对照组,每组设3个重复,每重复12头猪。试验组在正常饲粮中添加0.2%的小肽复合剂,对照组为正常饲粮。试验结果发现:育肥阶段饲喂0.2%的小肽复合剂能够显著提高育肥猪生长性能和改善肉质性状。表现为提高育肥猪的日增重(P<0.05),增加育肥猪的采食量,提高饲料转化效率,提高育肥猪群的成活率,降低生病率和腹泻率。肉质性状方面,显著降低滴水损失(P<0.05),增加了肌肉的保水力,生长性能和肉质性状的改善显著地提高了育肥猪的综合经济效益。     

The effects of halothane sensitivity on carcass composition and meat quality in HAL-1843-normal pigs

Objectives of this study were to determine the incidence of halothane sensitivity in pigs that are homozygous normal at the ryanodine receptor nucleotide 1843 (HAL-1843-normal) and the relationships between halothane sensitivity and carcass composition or meat quality. In Exp. 1, piglets (Lines A, B, C, and D; n = 168, 170, 168, and 169, respectively) were obtained from mating a HAL-1843-normal sire line to four HAL-1843-normal dam lines. In Exp. 2, piglets from Lines A and B (n = 87 and 90, respectively) were included with piglets (Lines E, F, G, and H; n = 94, 92, 89, and 89, respectively) obtained from mating four HAL-1843-normal sire lines to a single HAL-1843-normal dam line. Pigs were subjected to 3% halothane at approximately 9 wk of age. In Exp. 1, limb rigidity, blotching of the skin, and muscle tremors were visually assessed, and based on these criteria, halothane sensitivity (HS) was observed in 48% of the pigs. To better characterize this response, a scoring system was developed and used in Exp. 2. Using this system, 25, 42, and 33% of the pigs in E and 40, 33, and 27% of the pigs in Line G were categorized as HS-low (HS-L), HS-intermediate (HS-I), and HS-high (HS-H), respectively. In Lines F and H, 13 and 18% of the pigs were HS-I, and 0 and 2% were HS-H, respectively. No consistent effects due to HS were observed in carcass composition or meat quality; however, when a subset of pigs from Exp. 2 were subjected to more extensive handling and transportation before slaughter, ultimate pH was lower and drip loss was higher in LM from HS-H compared with HS-L pigs (P < 0.05; n = 71). These results demonstrate that some pigs are sensitive to halothane anesthesia even in the absence of the known HAL-1843 polymorphism. Additionally, halothane sensitivity may be associated with inferior pork quality under adverse antemortem conditions.     

Effect of age at slaughter on carcass traits and meat quality of Italian heavy pigs

Barrows and gilts (n = 128) from four breed crosses were used to investigate the effect of age at slaughter on carcass traits, proteolytic enzyme activity, and meat and fat quality. Pigs were blocked by breed cross into four blocks, and within blocks, one pen (eight barrows and eight gilts) was assigned randomly to be slaughtered at either 8 or 10 mo of age. Pigs were fed a corn-barley-soybean meal finisher diet from 104 +/- 2.5 d of age (37.7 +/- 0.33 kg BW) to the appropriate slaughter age. Carcasses from older (10 mo) pigs had lower (P < 0.01) muscularity indexes and lean cut yields than those of younger (8 mo) pigs, but dressing percentage and longissimus muscle area increased (P < 0.01) with age. Older pigs produced a redder (P < 0.01) and darker (P < 0.05) semimembranosus, with lower (P < 0.01) ultimate pH and cathepsin B and B + L activities, as well as higher (P < 0.01) aminopeptidase hydrolyzing activity than younger pigs. Moreover, the longissimus muscle of pigs slaughtered at 10 mo of age had lower (P < 0.01) drip and cooking loss percentages than that from pigs slaughtered at 8 mo of age. Ham subcutaneous fat from 10-mo-old pigs had greater (P < 0.05) percentages of oleic acid and lower (P < 0.01) proportions of moisture, linoleic, and linolenic acids than subcutaneous fat from pigs slaughtered at 8 mo of age. Results from this study indicate that fresh hams from pigs slaughtered at 10 mo of age would be more suitable for the production of high-quality, Italian, dry-cured hams.     

斜发沸石添加水平对育肥期苏淮猪生长性能、屠宰性能和肉品质的影响

本试验研究基础日粮中添加不同水平的斜发沸石对育肥期苏淮猪生长性能、肉品质的影响,旨在获得苏淮猪育肥期斜发沸石的适宜添加量。选择体重相近(50 kg左右)、健康的苏淮阉公猪40头,随机分为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组共4个处理组,每组10头。预试期10 d,所有猪自由采食对照组基础日粮;正试期64 d,对照组饲喂基础日粮,试验Ⅰ至Ⅲ组分别在基础日粮中添加0.5%、1.0%和2.0%的斜发沸石。于试验结束屠宰全部试验猪,用于屠宰测定和肉质检测。结果表明:1)第1阶段(体重56~68 kg)和第2阶段(体重83~98 kg),终末体重、平均日增重、料重比均无显著差异;但斜发沸石水平对第1阶段和第2阶段平均日采食量影响显著(P<0.05)并呈线性(P=0.02,P=0.047)二次方升高趋势(P=0.01)。2)对照组、试验Ⅰ组、Ⅱ组和Ⅲ组苏淮猪的生长曲线拐点分别是:第50.26天86.06 kg、第40.22天87.15 kg、第38.27天89.69 kg和第45.98天89.02 kg;最大日增重分别是0.702、0.743、0.814和0.855 kg/d,说明在饲料中添加斜发沸石后,可延长育肥猪到达生长曲线拐点体重。3)斜发沸石水平对眼肌面积和肌内脂肪影响显著(P<0.05),眼肌面积随斜发沸石添加水平的升高,呈二次方(P=0.01)变化;肌内脂肪呈线性(P=0.01),二次方(P=0.03)升高;胴体重和系水力分别随斜发沸石添加水平的升高,呈线性(P=0.07,P=0.09)升高趋势。试验表明:苏淮育肥猪采食量、胴体重和肌内脂肪随日粮斜发沸石添加水平增加呈线性升高,系水力呈线性升高趋势,但眼肌面积随斜发沸石添加水平的升高,呈二次方变化,先升高后降低。因此,添加2%斜发沸石有利于采食量、胴体重和肌内脂升高,有助于系水力降低;但从增加眼肌面积的角度考虑,斜发沸石的适宜添加比例为1%。     

Dietary mulberry leaf powder affects growth performance,carcass traits and meat quality in finishing pigs

This study was conducted to evaluate the effect of mulberry leaves as an alternative source of protein on growth performance, carcass traits and meat quality in finishing pigs. A total of 180 Xiangcun Black pigs were randomly assigned to five treatment groups with six pens of six pigs per pen. The pigs were provided with a basal diet or a diet contained 3%, 6%, 9% or 12% of mulberry leaf powder during a 50‐day experiment period. The results showed that dietary mulberry leaf powder had no negative effect on growth performance in Xiangcun Black pigs, except in the 12% mulberry group, where final body weight and average daily gain decreased (p < .05) and feed to gain ratio of the pigs increased (p < .05). Dietary mulberry inclusion decreased (quadratic, p < .05) the back fat thickness, fibre mean cross‐sectional area (CSA) in the longissimus dorsi (LD) muscle and mRNA expression levels of myosin heavy chain (MyHC) IIb in LD and biceps femoris (BF) muscles, while increased (linear or quadratic, p < .05) the plasma concentration of albumin, levels of crude protein (CP), inosine monophosphate (IMP) and several amino acids in muscle tissues. When compared with the other groups, the 9% mulberry diet increased (p < .05) loin‐eye area and contents of CP and IMP in muscles, while decreased (p < .05) plasma activity of cholinesterase and concentrations of uric acid and urea. The 6% mulberry diet had the lowest fibre mean CSA and shear force and increased total fibre number of the LD muscle, when compared with the other groups. These results suggest that including mulberry in the diet at <12% is an effective feed crop to improve meat quality and the chemical composition of muscle without negatively affecting growth performance.     

复合维生素添加剂对肉猪肥育性能、胴体性状和肌肉品质的影响

<正>国内外先进养猪技术的应用,使猪胴体瘦肉率、生长速度和饲料报酬有了较大幅度的提高,这种提高却是以猪肌肉品质下降为代价的,因此如何利用营养     

Impact of dietary energy level and ractopamine on growth performance, carcass characteristics, and meat quality of finishing pigs

A total of 54 finishing barrows (initial BW = 99.8 ± 5.1 kg; PIC C22 × 337) reared in individual pens were allotted to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement of treatments with 2 levels of ractopamine (0 and 7.4 mg/kg) and 3 levels of dietary energy (high, 3,537; medium, 3,369; and low, 3,317 kcal of ME/kg) to determine the effects of dietary ractopamine and various energy levels on growth performance, carcass characteristics, and meat quality of finishing pigs. High-energy diets were corn-soybean-meal-based with 4% added fat; medium-energy diets were corn-soybean meal based with 0.5% added fat; and low-energy diets were corn-soybean meal based with 0.5% added fat and 15% wheat middlings. Diets within each ractopamine level were formulated to contain the same standardized ileal digestible Lys:ME (0 mg/kg, 1.82; and 7.4 mg/kg, 2.65 g/Mcal of ME). Individual pig BW and feed disappearance were recorded at the beginning and conclusion (d 21) of the study. On d 21, pigs were slaughtered for determination of carcass characteristics and meat quality. No ractopamine × energy level interactions (P > 0.10) were observed for any response criteria. Final BW (125.2 vs. 121.1 kg), ADG (1.2 vs. 1.0 kg/d), and G:F (0.31 vs. 0.40) were improved (P < 0.001) with feeding of ractopamine diets. Feeding of the low-energy diet reduced (P = 0.001) final BW and ADG compared with the high- and medium-energy diets. Gain:feed was reduced (P = 0.005) when the medium-energy diets were fed compared with the high-energy diets. Additionally, G:F was reduced (P = 0.002) when the low-energy diets were compared with the high- and medium-energy diets. Feeding ractopamine diets increased (P < 0.05) HCW (93.6 vs. 89.9 kg) and LM area (51.2 vs. 44.2 cm(2)). The LM pH decline was reduced (P ≤ 0.05) by feeding ractopamine diets. The feeding of low-energy diets reduced (P = 0.001) HCW when compared with the high- and medium-energy diets and reduced (P = 0.024) 10th-rib backfat when compared with the high- and medium-energy diet. These data indicate that feeding ractopamine diets improved growth performance and carcass characteristics, while having little or no detrimental effect on meat quality. Reductions in energy content of the diet by adding 15% wheat middlings resulted in impaired ADG, G:F, and 10th-rib backfat. There were no ractopamine × energy level interactions in this trial, which indicates that the improvements resulting from feeding ractopamine were present regardless of the dietary energy levels.