Association of DGAT2 gene polymorphisms with carcass and meat quality traits in domestic pigeons (Columba livia)

1. Diacylglycerol acyltransferase (DGAT) plays an important role in the synthesis of triacylglycerol, but its effects on meat quality and carcass composition in pigeons are unclear. In this study, single-nucleotide polymorphisms (SNPs) in the exons of the DGAT2 gene were identified and analysed by using DNA sequencing methods in 200 domestic pigeons (Columba livia). The associations between DGAT2 polymorphisms and carcass and meat quality traits were also analysed.

2. Sequencing results showed that 5 nucleotide mutations were detected in exons 3, 4, 5 and 6 of the DGAT2 gene. The analysis revealed three genotypes (AA, AB and BB) in G18398T and G22484C, in which the AA genotype and A allele had the highest frequency.

3. In the SNP of G18398T located in exon 5, individuals with genotype BB had significantly higher meat quality and lower abdominal fat content than those with AA or AB genotype. In the SNP of G22484C located in exon 6, the genotype AA showed highest carcass trait values, while the genotype BB represented better meat quality, compared to AA and AB genotypes.

4. The results imply that DGAT2 gene has a close relationship with carcass and meat quality traits in pigeons, and the SNPs of G18398T and G22484C can be used as genetic markers for marker-assisted breeding in pigeon.     

The temporal-spatial patterns,polymorphisms and association analysis with meat quality traits of FABP1 gene in domestic pigeons (Columba livia)

ABSTRACT

1. Fatty acid-binding proteins (FABP) are members of lipid-binding proteins, which participate in the metabolism and intracellular transportation of lipids. This study was designed to investigate the expression patterns, polymorphisms and associations with meat quality traits of the FABP1 gene in pigeons.

2. The temporal-spatial expression patterns showed FABP1 was widely expressed in all eleven tissues from 0–4 weeks of age, the expression level in the liver was the highest, followed by the small intestine and subcutaneous fat.

3. Five novel SNPs were found; all of them were synonymous and in Hardy-Weinberg equilibrium. Association analysis revealed that for the SNP of G161C, the AB and BB genotypes had higher (P ≤ 0.01) inosinic acid concentrations in breast muscle than the AA genotype. The BB genotype showed the highest (P < 0.01) intramuscular fat among the three genotypes, and significantly greater FABP1 mRNA levels were observed in the breast muscle of the BB genotype than in the AA and AB genotypes (P < 0.01). In the SNP C1376T, the AB and BB genotypes showed higher (P < 0.01) intramuscular fat than the AA genotype, and the relative mRNA expression level of the BB (P < 0.01) and AB (P < 0.05) genotypes was higher than that of the AA genotype in breast muscle. Correlation analysis implied that the FABP1 mRNA expression level was closely related to the inosinic acid (P < 0.05) and intramuscular fat content (P < 0.01). Oil red O staining of frozen sections of breast muscle on d 28 for SNPs G161C and C1376T also indicated that the BB genotype had the highest intramuscular fat content in both SNPs. In addition, correlation analysis implied the FABP1 mRNA expression level was closely related to inosinic acid (P < 0.05) and intramuscular fat content (P < 0.01).

4. The results suggested that FABP1 could be a potential candidate gene in marker-assisted selection for breeding pigeons with high-quality meat.     

Association of MYF5 and KLF15 gene polymorphisms with carcass traits in domestic pigeons (Columba livia)

1. Single nucleotide polymorphisms (SNPs) in the exons of the myogenic factor 5 (MYF5) and Kruppel-like factor 15 (KLF15) genes were identified and analysed by using DNA sequencing methods in 60 female domestic pigeons (Columba livia).

2. Five SNPs (T5067A, C5084T, C5101T, T5127A and C5154G) were detected in exon 3 of MYF5 and 6 SNPs (C1398T, C1464T, G1542A, C1929T, G1965A and A2355G) were found in exon 2 of KLF15, respectively. The analysis revealed three genotypes, in which the AA genotype was dominant and the A allele showed a dominant advantage.

3. For the MYF5 gene, the C5084T and T5127A SNP genotypes were significantly associated with carcass traits of pigeons. Within those two SNPs, the BB genotype showed relatively higher trait association values than those of AA or AB genotypes. No significant association was observed between the KLF15 SNP genotypes and carcass traits.

4. These results indicated that the MYF5 gene is a potential major gene affecting carcass traits in domestic pigeons. The BB genotype of the C5084T and T5127A SNPs could be a potential candidate genetic marker for marker-assisted selection in pigeon.

     

Ob基因对松辽黑猪肉质和胴体性状的影响

以松辽黑猪为研究对象,分析Ob基因对其肉质和胴体性状的影响。测定30头松辽黑猪的9个肉质性状和6个胴体性状,用PCR-RFLP方法检测Ob基因型。结果显示,松辽黑猪TT基因型平均膘厚比CT基因型低,而肌内脂肪含量、瘦肉率则显著高于后者(P<0.05),其他肉质和胴体性状在Ob基因型间没有显著差异(P>0.05)。结果表明,Ob基因的TT基因型对猪的肉质和胴体性状具有显著的正遗传效应。     

L.fermentum F-6对肉鸡屠宰性能及肌肉品质的影响

试验旨在研究添加不同剂量的L.fermentum F-6对肉鸡的屠宰性能及肌肉品质的影响,进一步探讨其作为一种新型饲料益生菌的可行性。试验以玉米和大豆粕为主要原料配制日粮,采用单因子完全随机试验设计方法,选择1日龄雌雄各半的健康AA肉鸡240只,称重后随机分为4个组,其中1个对照组和3个L.fermenti F-6组,每个组6个重复,每个重复10只鸡,各组鸡的初始体重经方差检验差异均不显著(P>0.05)。对照组肉鸡不饲喂L.fermentiF-6,L.fermentiF-6组饮水饲喂L.fermentiF-6,添加水平分别为2×105、2×106和1×107 cfu/ml,试验期42 d。研究结果表明,添加L.fermenti F-6可显著提高肉鸡全净膛率和胸肌率(P<0.05),提高肉鸡屠宰性能,其中以添加剂量为2×106 cfu/ml时效果较好。添加L.fermenti F-6对肉鸡肌肉pH值、系水力和肉色指标无显著影响,但与对照组相比,L.fermentum F-6对肌肉系水力和肉色有一定改善效果。     

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.     

甜菜碱对育肥猪生长性能、胴体品质和肉质的影响

试验选用体重70 kg左右、日龄相近、体质良好的杜长大三元杂交猪45头,采用单因子随机设计,分为对照组、试验1、2、3、4组,每组3个重复,分别饲喂添加0、500、1000、1500、2000 mg/kg甜菜碱的日粮,试验期30 d,研究甜菜碱对肥育猪生长性能、胴体品质和肉质的影响。结果表明,与对照组相比,试验2、3、4组日均采食量、日增重、屠宰率、瘦肉率、肉色评分、大理石评分显著提高(P<0.05),背膘厚度显著降低(P<0.05),试验1组各项指标有所改善,但效果不显著(P>0.05),本试验表明,饲料中添加甜菜碱可提高育肥猪生长性能,改善胴体品质和肉品质,其中添加1500、2000 mg/kg的甜菜碱效果较为理想。     

早胜牛A-FABP基因SNPs与胴体品质和肉质性状的关系

为研究早胜牛（Bos taurus）A-FABP基因多态性与胴体品质和肉质性状的相关性,采用PCR-SSCP方法对5个早胜牛群体（庆阳群体、平凉群体、南德温与庆阳杂种群体、西门塔尔与平凉杂种群体、秦川与平凉杂种群体）A-FABP基因型进行了测定,并分析其多态性与胴体品质和肉质性状的相关性。结果表明,A-FABP基因第2外显子区c.280AG,并检测到3种基因型AA、AG和GG。对屠宰后胴体和肉质性状相关分析表明,基因型AG屠宰率极显著高于AA（P0.01）,而净肉率GG极显著高于AA（P0.01）;基因型AG剪切力显著低于AA（P0.05）。由此认为A-FABP基因突变位点可作为早胜牛胴体性状和肉质性状遗传标记。     

肉鸡品种对胴体性状和肉质的影响

本研究将清远麻鸡的两个纯系(A和B)与快速生长型AA肉鸡(C)杂交,在3个月的生长时间中测定了杂交品对肉鸡胴体性状、肌肉成分及氨基酸组成的影响.结果:杂交品系肉鸡的体重、屠体重、半净膛重、全净膛重、胸肌和腹脂重量均显著高于纯种品系(P<0.05).杂交品系肉鸡的肌纤维密度和剪切力较纯种品系显著提高了6.94％和7.98...     

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%。     

Effect of mydriasis with topical rocuronium bromide on electroretinography in domestic pigeons (Columba livia)

This study aimed to investigate the effect of mydriasis using topical rocuronium bromide on electroretinography (ERG) in domestic pigeons (Columba livia). Scotopic mixed rod and cone, photopic cone, and photopic flicker ERG were performed on nine eyes of nine healthy adult pigeons under sedation. Each pigeon underwent two sets of ERG recordings. First, without the induction of mydriasis (control) and the second time with the induction of mydriasis using topical rocuronium bromide (treatment). The results were compared using either the Student’s t-test or Wilcoxon rank-sum test, where a P-value of <0.05 was considered statistically significant. No significant differences were observed in the a- and b-wave implicit times and amplitudes during scotopic ERG between the two groups. The a- and b-wave amplitudes in the photopic cone were significantly higher in the treatment group (63.83 ± 32.33 and 191.75 ± 94.46 µV) compared to the control group (46.15 ± 27.60 and 116.76 ± 70.65 µV; P=0.045 and P=0.032, respectively). The photopic flicker amplitude was also significantly higher in the treatment group (76.23 ± 48.56 µV) than in the control group (42.18 ± 31.18 µV; P=0.044). No statistically significant differences were observed in the photopic cone and flicker implicit times between both groups. In conclusions, mydriasis induced by rocuronium bromide in pigeon resulting in higher amplitudes during the photopic ERG but not scotopic ERG.     

牛CAPN3基因多态性及与肉质性状相关性分析

以中国草原红牛、西门塔尔牛、利木赞牛、天一冈山黑牛为试验对象,利用PCR-SSCP结合测序的方法进行SNPs检测,并采用SPSS软件分析CAPN3基因的遗传多态性与肉质性状的关系。结果表明,仅在草原红牛及天一冈山黑牛中发现第46 414处（NC_007308）发生G→T的突变,且发生G→T突变的位点所对应不同基因型的个体,其大理石花纹、失水率、滴水损失和剪切力这些肉质性状存在显著差异,而西门塔尔牛和利木赞牛中未发现此突变。     

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     

谷胱甘肽对肉羊生长性能、屠宰性能及肉品质的影响

选择东北细毛羊×德国肉用美利奴的杂交一代肉羊12只,分成对照组、试验Ⅰ组和Ⅱ组,每组4只,研究谷胱甘肽对肉羊生长性能、屠宰性能及肉品质的影响。试验期60 d。结果表明:与对照组相比,谷胱甘肽显著提高了肉羊的日增重(P<0.05),试验Ⅰ组、Ⅱ组分别提高了14.6%和11.4%;降低了肉羊的料重比(P<0.05),试验Ⅰ组、Ⅱ组分别降低了11.0%和8.1%。试验Ⅰ组的净肉率和GR值显著高于对照组(P<0.05),Ⅱ组的宰前活重显著高于对照组(P<0.05);试验Ⅰ组肉的剪切力显著低于对照组(P<0.05);试验Ⅰ组、Ⅱ组的滴水损失显著低于对照组(P<0.05),而熟肉率显著高于对照组(P<0.05),且两试验组间差异不显著(P>0.05);各试验组宰后45 min内肉的pH没有显著差异(P>0.05),但试验Ⅰ组24 h的pH极显著地高于其他2组(P<0.01)。     

Effects of growth rate on carcass and meat quality traits and their association with metabolism-related gene expression in finishing pigs

The objective of this study was to evaluate the effect of different growth rates on carcass characteristics and meat quality and their relationship with myogenesis and lipogenesis in finishing pigs. Pigs were slaughtered at the same age and were assigned to high (HGR) or low (LGR) growth rates with 120 kg or 110 kg final body weights at slaughter. The results indicated that pigs with HGR had heavier (P < 0.05) final body weight, carcass weight, dressing percentage, backfat thickness, higher (P < 0.05) concentrations of fat in the muscle and higher (P < 0.05) total RNA concentration in muscle than pigs with LGR. The messenger RNA (mRNA) expression of lipoprotein lipase, fatty acid synthase, malic enzyme, peroxisome proliferator-activated receptor γ, and sterol regulatory element binding protein-1 in fat were higher (P < 0.05) in pigs with HGR. Additionally, the mRNA expression of glycogen synthase in muscle was lower (P < 0.05) in pigs with HGR. These results indicate differences in postmortem myogenesis and lipogenesis traits of pigs with different growth rates; these differences in turn might have affected carcass characteristics and meat quality.     

Physiological and hormonal aspects in female domestic pigeons (Columba livia) associated with breeding stage and experience

The present study examined the changes in serum biochemical values, hormone profiles and ovary prolactin receptor (PRLR) gene expression occurring in female domestic pigeons (Columba livia) under different breeding status and experience. The egg‐laying pigeons had lower calcium, total protein, albumin, prolactin levels and higher oestrogen levels than those of incubating birds (p < 0.05). First‐time breeders had higher (p < 0.05) progesterone levels and lower (p < 0.05) prolactin levels than that of experienced ones. The levels of oestrogen and follicle‐stimulating hormone (FSH) increased with age (p < 0.05). The very old birds showed a pronounced increase (p < 0.05) in PRL, FSH and progesterone and a little decrease in oestrogen. Serum prolactin level was not correlated with the ovary PRLR mRNA expression pattern among all the pigeons. Results showed that serum physiological profile of female pigeons was correlated with breeding status, whereas reproductive hormone levels were correlated with advancing breeding experience. It was concluded that female pigeons had a good ability of recovering from nutrient loss after each breeding attempts, and the degradation of reproductive performance might be attributed to changes in the endocrine system.     

Efficacy of topical rocuronium bromide as a mydriatic agent in domestic pigeons (Columba livia)

This study was conducted to investigate the efficacy of rocuronium bromide as mydriatic agent in domestic pigeons (Columba livia). This study was done in two phases. In the first phase, rocuronium bromide (0.20 mg/20 µl) was topically instilled to the right eye (OD) of eight domestic pigeons. Pupil diameter was measured before instillation (T0), and at 5 (T05) and 10 (T10) min after instillation, and every 10 min thereafter until 160 (T160) min. Pupillary light reflex (PLR) was assessed using a scoring system at the same time points. In the second phase, the same dosage was instilled twice in the span of 10 min into both eyes (OU) of four pigeons (eight eyes). Measurements were done accordingly. The iris color in the first phase were: gravel, pearl and bull eye. All irises in the second phase were bull eye. Mydriasis were observed in 6/8 (75%) pigeons in the first phase. Maximal mydriasis was observed at T30 (mean pupil diameter=4.62 ± 0.13 mm). Pupil diameter in the treated eye was significantly different from contralateral eye and from T0 since T05 (P=0.017 and P=0.006, respectively)−T120 (P=0.043 and P=0.044, respectively). PLR was disappeared from T10 (P=0.034) to T90 (P=0.041). In the second phase, mydriasis was only observed in 2/8 eyes. This study suggested that rocuronium bromide was able to produce mydriasis in pigeons other than bull eye iris.     

The influences of weaning age and weight on carcass traits and meat quality of pigs

The purpose of this study was to establish the effects of weaning age and weight on pigs, and their interaction with carcass traits and meat quality. A total of 468 piglets were obtained from 57 sows and four boars and grouped by age at weaning (D21, 18–24 days; D28, 25–32 days). Each weaning group was subdivided into three weight groups (L, M and H) according to weaning weight. The D28 group had heavier carcass weight, redness and yellowness, but had lower marbling scores and less drip loss than the D21 group (P < 0.05). The pigs with a light weight at weaning had higher carcass weights and lower yellowness than did pigs with a medium or heavy weight at weaning (P < 0.05). Weaning age was found to have a negative correlation with drip loss, while weaning weight was negatively correlated with carcass weight and drip loss (P < 0.05). We concluded that carcass and meat quality traits in pigs were significantly related to their age and weight at weaning. Therefore, we find that piglet weaning age and weight are no less important than post‐weaning growth performance and behavior, with regard to carcass traits and meat quality.     

Evaluation of the four breeds in synthetic line of Jiaxing Black Pigs and Berkshire for meat quality traits,carcass characteristics,and flavor substances

To investigate breed characteristics and the effect of hybridization of Jiaxing Black Pig (JBP) with Western breeds, the carcass and meat quality traits and flavor substances such as inosinic acids (IMP), intramuscular fat (IMF) in longissimus muscle (LM) from five breeds including JBP, Berkshire, Berkshire × JBP (BJBP), Duroc × Berkshire × JBP (DBJBP), Duroc × Landrace × JBP (DLJBP) were compared in this study. It was found that water holding capacity (WHC) of LM in JBP was significantly higher than that in the other strains (p < 0.01). Dressing out percentage and lean percentage of JBP were both significantly lower than those in the others (p < 0.01) in connection with their lighter carcass weight and higher subcutaneous fat percentage (p < 0.01). Heterosis was realized in DJBP, DBJBP, and DLJBP since their carcass weight, lean percentage, and loin eye muscle area (LEMA) were markedly higher when compared to JBP, whereas lower than those in Berkshire. Among the breeds, the content of IMF and IMP in the LM of JBP were the highest. These traits were also palpably improved in the crossbreds, especially for DBJBP, of which pork was considered outstanding for containing the most abundant essential amino acids (EAA) and total amino acids (TAA).