Association of allelic polymorphisms of IGFALS gene with growth traits in Makouei and Ghezel sheep breeds

Insulin-like growth factor-binding protein acid-labile subunit (IGFALS) encodes a protein which binds to IGF1 and IGFBP-3 to regulate the growth, differentiation, and other physiological processes. The aim of this study was the identification of allelic polymorphisms of the IGFALS gene using the PCR-RFLP technique and evaluation of their association with growth traits. For this end, 120 blood samples were randomly collected from each breed. Following amplification of an 1113-bp fragment of exon 1 and a part of intron 1 of the IGFLAS gene, genotyping was conducted by three restriction enzymes including HinfI, MscI, and PvuII. The results showed that only one allele was observed in IGFALS-PvuII site, while in IGFLAS-MscI site, three AA, AB, and BB genotypes with the frequencies of 17.5%, 32%, and 50.5% and 11%, 37.5%, and 51.5% were observed in Makouei and Ghezel sheep breeds, respectively. Additionally, in the IGFLAS-HinfI site, two AB and BB genotypes with the frequency of 34.2% and 65.8% were observed in Makouei sheep and AA, AB, and BB genotypes with the frequency of 9%, 21%, and 70% were observed in Ghezel sheep. So that, Makouei sheep with AB genotype had more chest girth (CG) compared with other genotypes. Furthermore, a significant association was observed between the genotypes of IGFLAS-HinfI with birth weight (BW) in Ghezel and BW, weaning weight (BW3), and CG in Makouei sheep. Haplotype analysis revealed an association between paternal haplotypes and BW in both Ghezel and Makouei breeds. So that, AAB and ABB haplotypes showed more BW than others in Makouei and Ghezel sheep, respectively.

     

The influence of age and gender on haematological parameters in Lipizzan horses

Haematological parameters [red blood cell count (RBC), white blood cell count (WBC), packed cell volume (PCV), haemoglobin concentration, mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC)] in resting Lipizzan horses were determined for 143 stallions, 104 mares and 25 foals. The mean RBC and WBC values in Lipizzans were in the lower part of the normal range for warm-blooded horses. The mean PCV, MCV and MCH values were higher, but the mean haemoglobin concentration and MCHC values were lower than reported for other warm-blooded horses. In foals, the mean RBC, WBC, PCV, haemoglobin concentration and MCHC values were higher, whereas MCV and MCH were lower than in older animals. Results indicating a significant decrease in WBC (P < 0.01) and an increase in MCV, MCH and MCHC (P < 0.05) with increasing age are consistent with some other reports on warm-blooded horses. The age-related variations in RBC and PCV were less marked. Contrary to some reports, RBC (P < 0.01), WBC and haemoglobin concentration (P < 0.001) were higher in Lipizzan stallions than in mares, but differences in MCHC, MCH and MCV were insignificant. The specific haematological values determined in Lipizzans are presumably a result of selection and should be taken into consideration when dealing with this race of horses.     

Effect of parenteral iron doses on the measurement of red blood parameters and on weight development in lambs of different breeds

Conventionally reared male and female lambs of Merinoland- (n = 87) and Rh?n sheep (n = 30) were injected at day 3 of age with 300 mg iron dextran. Body weight of the animals was determined and blood samples were taken at day 3, 10, 21 and 42 of age. Glutathione (GSH) and haemoglobin (Hb) concentrations in blood, haematocrit (PCV), mean corpuscular haemoglobin concentration (MCHC) as well as haemoglobin-type (Hb-type) and the occurrence of foetal and anaemic Hb-bands after electrophoretic separation were determined. Data were analysed by least squares procedures where the effects of breed, sex, number of lambs born, Hb-type, foetal and anaemic Hb-bands were considered as fixed factors. Independent of all fixed factors, the application of iron dextran increased daily gain from day 3 to 10 of age in all lambs treated. Mainly twins and male lambs showed higher daily gains in this period when compared with the control groups. In untreated lambs lower values for blood parameters were observed within the first week of life, but no negative influence was found in daily gain until day 42. Between Merinoland- and Rh?n sheep, significant differences in GSH concentration of blood where found which were not influenced by the application of iron. Lambs with a detectable foetal band at day 42 of age showed significant lower daily gains, MCHC, and Hb-concentrations when compared with lambs lacking this band. Interactions between occurrence of anaemic band and erythrocyte measurements could not be shown.     

Observations on Haemoglobin Types in Three Breeds of Omani Goats

Haemoglobin (Hb) types were studied in three breeds of Omani goats, Batinah (n = 22), Jebel Akhdar (n = 27) and Dhofari (n = 85). Type A was the only adult Hb observed in adult Batinah and Jebel Akhdar goats. In contrast, only 34% of the Dhofari goats were homozygous for Hb A, while 66% were heterozygous for Hb A and Hb B. Dhofari goats with type AB could further be differentiated into those with approximately 67% type A and 33% type B and those with approximately 33% type A and 67% type B. None of the goats was homozygous for type B. Seventeen kids observed from birth exhibited different levels of fetal Hb, dependent upon whether they developed the adult phenotype AA or AB. Kids that became homozygous for type A were born with approximately 90% Hb F and 10% Hb A. In contrast, goats that developed the heterozygous AB phenotype were born with only 30–60% Hb F, the remaining Hb being types A and B. These findings are not in accordance with previous reports that kids are born without any adult Hb. Hb F was no longer detectable in any of the three breeds of goats at 49 days of age. There was no evidence of Hb C, the pre-adult form of Hb.     

Reference values of the red blood profile in beagle, German shepherd and golden retriever puppies

In the present study, blood samples were taken from clinically healthy puppies of the breeds Beagle, German Shepherd, and Golden Retriever between days 1 and 3 (n = 146), 8 and 10 (n = 137), 28 and 33 (n = 151), and 50 and 58 (n = 129) post natum. Measurements for red blood cell count, haemoglobin concentration, haematocrit, mean erythrocyte volume (MCV), mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC) were performed by a semi-automatic blood cell counter; the normoblast number was counted visually. Between the 1st and 3rd day of life, the erythrocyte number of the puppies was 4.57 +/- 0.68 10(6)/microliter and, as such, was clearly below the reference range for adult animals. It further decreased by the 2nd measurement (8th to 10th day of life) to 3.59 +/- 0.41 10(6)/microliter, and then increased again to 4.75 +/- 0.68 10(6)/microliter (reference range: 3.73-6.25 10(6)/microliter, 2.5% to 97.5% percentile) by the final measurement (50th to 58th day of life). The measurement values of the haemoglobin concentration (13.5 +/- 2.0 g/dl) and haematocrit (41.0 +/- 6.5%) after birth were only insignificantly below or around the lower limit of the reference range for adult animals. Both parameters decreased to a more pronounced extent than did the erythrocyte count. They reached a minimum of 8.4 +/- 1.0 g/dl and 26.8 +/- 3.2%, respectively, between the 28th and 33rd day of life. Even at the end of the examination period (50th to 58th day of life), the values of these parameters (10.1 +/- 1.1 g/dl, reference range: 7.5-11.8 g/dl; 32.1 +/- 4.2%, reference range: 24.8 to 40.8%) were remarkably lower than the minimum of reference range for adult dogs. At the 1st sampling (between 1st and 3rd day of life), MCV (89.8 +/- 6.7 fl) and MCH (29.6 +/- 1.9 pg) were distinctly higher than the reference values for adult dogs. Both parameters decreased with increasing age. Thus, from the 50th-58th day of life, the results were comparable to those of adults. No considerable age dependence was found for MCHC. During the first days of life a relatively high number of normoblasts (8 +/- 7/100 Leukozyten) was found; it decreased rapidly. The study revealed significant differences between the breeds, e.g. German Shepherd dogs had lower initial values of erythrocyte count, haemoglobin concentration, and haematocrit when compared to the other breeds. Puppies of this breed also had higher normoblast numbers than the Beagle and Golden Retriever puppies at the 2nd and 3rd samplings. No clear sex differences in the studied parameters were observed. The results of this study reflect the replacement of fetal erythrocytes by postnatal erythrocytes. Moreover, they illustrate the need to use age as well as breed-specific reference ranges.     

Level of heavy metals in the liver of sheep in experimental poisoning with copper oxide from industrial emissions

The life span and cumulation of heavy metals in the liver of 12 ewes of the Improved Wallachian breed were investigated in relation to feeding pollutants from a copper works. The total intake of copper, iron, zinc, arsenic, cadmium and lead was 466.8; 1253.93; 111.67; 34.75; 0.091; 2.13 mg per experimental animal/day, respectively. The average life span of ewes in the experimental group was 77 days. The difference between the first and the last animal which died from copper intoxication was 18 days. The concentration of copper in the liver of sheep who died from intoxication by this metal (2138.28 +/- 1090.96 mg. kg-1 in dry matter) was significantly higher (p less than 0.01) if compared with the control ewes (212.9 +/- 58.33 mg. .kg-1 in dry matter). In the course of observations no direct dependence between the concentration of copper in the liver and the life span of experimental animals was confirmed. The content of iron and zinc in the liver of experimental animals was within the reference range; the difference in zinc was statistically significant when compared with the control group (p less than 0.01). The intake of pollutants from the copper works increased significantly the concentration of arsenic and lead in the liver of experimental animals (p less than 0.01) if compared with the control group. The amount of cadmium in the liver of experimental ewes was 0.304 +/- 0.22 mg. .kg-1 and in the control ewes 0.285 +/- 0.10 mg.kg-1 in dry matter; no significant difference was determined at the same time.     

小尾寒羊高繁殖力候选基因RBP4的研究

以视黄醇结合蛋白4（retinol binding protein 4，RBP4）基因为候选基因，采用PCR-SSCP技术分析了RBP4基因在高繁殖力绵羊品种（小尾寒羊、湖羊）以及低繁殖力绵羊品种（多赛特羊、萨福克羊）中的单核苷酸多态性，同时研究这个基因对小尾寒羊高繁殖力的影响。结果表明：RBP4基因扩增片段在4个绵羊品种中存在PCR-SSCP多态性。BB基因型只出现在高繁殖力绵羊品种中，而低繁殖力绵羊品种则没有BB基因型；AB基因型频率随着绵羊繁殖力的降低而升高；AA基因型只出现在小尾寒羊、多赛特羊中。BB基因型小尾寒羊产羔数分别比AA和AB基因型多0．52只（Pd0．05）和0．67只（Pd0．05），AA和AB基因型小尾寒羊产羔数没有显著差异（P〉0．05）。本研究检测的绵羊RBP4基因座位与小尾寒羊高繁殖力相关。     

Response of Corriedale and Crioula Lanada Sheep to Artificial Primary Infection with Haemonchus Contortus

Clinical, parasitological and biochemical parameters were evaluated in Corriedale and Crioula Lanada sheep after a single experimental infection with Haemonchus contortus. Ten 4-month-old worm-free lambs, of each breed, were infected with 200 L₃ H. contortus per kg live weight and four uninfected animals of each breed were used as controls. Every week, the animals were weighed and blood and faecal samples were collected for measurement of packed cell volume (PCV), total serum protein (TSP) and albumin (ALB), and the number of eggs per gram of faeces (EPG), respectively. Twelve weeks after infection, the animals were slaughtered. The worm burden was determined and samples of the abomasal mucosa were processed for determination of the number of eosinophils, mast cells and globule leukocytes. No significant differences in PCV, TSP, ALB, parasite burden or the cell populations of the abomasal mucosa were observed between breeds, but Crioula lambs had a lower EPG count. The comparison of the infected groups with their respective controls revealed significant alterations in PCV, TSP and ALB in the Corriedale lambs and in PCV, TSP, ALB and the density of eosinophils and mast cells in the Crioula lambs.     

DNA polymorphism of 5' flanking region of prolactin gene and its association with litter size in sheep

A single nucleotide polymorphism of 5' flanking region of the prolactin gene was investigated in both high prolificacy breeds (Small Tail Han and Hu sheep) and low prolificacy breeds (Dorset and Suffolk sheep) using polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP). The results indicated that two genotypes (AA and AB) were detected in Small Tail Han sheep (n   =   239), only one genotype (AA) was detected in Hu (n   =   40), Dorset (n   =   50) and Suffolk sheep (n   =   39). The mutant homozygous genotype (BB) was not detected in four sheep breeds. In Small Tail Han sheep (n   =   239), the frequency of genotypes AA and AB was 0.91 and 0.09, the frequency of the A and B alleles was 0.95 and 0.05, respectively. The fitness tests showed that the Small Tail Han sheep population was in Hardy–Weinberg equilibrium. Sequencing revealed a mutation (G→T) at the position 63 bp of the 5' flanking region of prolactin gene in AB genotype compared with AA genotype in Small Tail Han sheep. The Small Tail Han ewes with AB genotype had 0.83 (p < 0.05) lambs more than those with AA genotype. These results preliminarily showed that the prolactin locus is either a major gene that influences the high prolificacy in Small Tail Han sheep or is in close linkage with such a gene.     

Effects of dietary protein and stage of lactation on the haematology and erythrocyte enzymes activities of high-producing dairy cattle.

Blood samples were collected monthly over a nine-month period from 19 high-producing Holstein-Friesian dairy cows. Dry cows on the lowest (13 per cent) protein ration had the highest mean values for packed cell volume (PCV), haemoglobin (Hb) and red blood cells (RBC). Among the lactating cows, the group on the 13 per cent protein diet had the highest mean PCV, Hb and RBC values. Other constituents were not affected significantly by dietary protein levels. Packed cell volume, RBC, Hb, serum iron (SI), iron binding capacity (IBC) and serum albumin concentrations decreased early in lactation and rose to pre-lactation levels by mid-lactation. PCV and Hb concentrations remained low for periods up to four months. RBC count was lowest in the second month while albumin concentration was lowest in the first month and remained low up to the second month. IBC was lowest in the first month of lactation while SI concentrations were lowest in the third month. There were no significant variations in the activities of erythrocyte glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD) and reduced glutathione (GSH). The 13 per cent protein ration had no anaemia-inducing effect on the cows.     

Evaluation of antioxidant status and oxidative stress in sheep naturally infected with Babesia ovis

The present study aimed to assess antioxidant status and oxidative stress in sheep naturally infected with Babesia ovis. Red blood cell (RBC) count, hemoglobin (Hb) concentration, packed cell volume (PCV), piroplasm parasitemia percentage, malondialdehyde (MDA) concentration, erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities and total antioxidant capacity (TAC) were determined in 52 sheep naturally infected with B. ovis as well as same number of healthy sheep in West-Azerbaijan province, Iran. Microscopic examination of Giemsa-stained peripheral blood smears revealed B. ovis infection. The parasitological diagnosis was confirmed using polymerase chain reaction (PCR) analysis by amplifying a partial small subunit ribosomal RNA (ssu rRNA) gene sequence of B. ovis of 52 diseased sheep, 18 (34.61%), 11 (21.15%), 16 (30.76%) and 7 (13.48%) had <1%, 1-2%, 2-3% and >3% parasitemia, respectively. Compared to controls, the activities of erythrocyte GSH-Px, SOD, TAC and CAT showed a significant decrease, whereas the concentration of MDA in erythrocytes of infected sheep increased significantly. Parasitemia rate was positively correlated with MDA and negatively correlated with PCV, SOD, CAT, GSH-Px and TAC. Also, MDA was negatively correlated with PCV, SOD, catalase, GSH-Px and TAC. The study demonstrated that B. ovis plays an important role in the occurrence of oxidative damage to RBCs and anemia in ovine babesiosis.     

Haemoglobin types of old Norwegian short tail land race sheep

Thirty years have passed since it was shown that sheep have two types of haemoglobin (Hb), A and B. Since then a large number of studies have been undertaken; gene frequencies, relations and origins of breeds, biochemistry, correlations with diseases, to mention the most important fields for which these 2 haemoglobins have been utilized. A few years ago, in a number of studies, Vestri and coworkers (Vestri et al. 1983) using chromatographic and biochemical methods together with isoelectric focusing showed that in Italian sheep additional Hb types occurred. These new types are caused by substitutions in the alpha chains, in contrast to the A and B difference which is caused by 7 amino acid substitutions in the beta chain (Huisman et al. 1965). Vestri et al (1983) also proved that the alpha chains in sheep, as in man, horse and goat among others, are controlled by 2 closely linked alpha globin genes.     

青海省绵羊品种与引进品种先天性免疫研究

为研究青海本地绵羊品种与引进品种的先天性免疫水平和品种特性,本研究选取青海省不同海拔地区的2个本地品种（欧拉羊、白藏羊）和1个引进品种（无角道赛特羊）共186只绵羊,采集新鲜血样,进行血常规检测（白细胞数（WBC）、红细胞数（RBC）、平均红细胞血红蛋白（HGB）、红细胞压积（HCT）、平均红细胞体积（MCV）、平均红细胞血红蛋白浓度（MCH）、血红蛋白浓度（MCHC）、血小板（PLT）、红细胞分布宽度（RDW-CV）、淋巴细胞百分比（LYM%））;制备血清,用绵羊ELISA试剂盒测定白介素-1（IL-1）、白介素-2（IL-2）、白介素-6（IL-6）、白介素-18（IL-18）、γ-干扰素（IFN-γ）、免疫球蛋白G （IgG）和主要组织相容性复合体（MHC）等免疫指标;分别以品种和品种来源地为因变量对检测结果进行比较分析。结果发现,以品种为因变量,无角道赛特羊的免疫水平最高,白藏羊的抗病性稍高于欧拉羊;以品种来源地为因变量时,本地绵羊品种的先天性免疫水平低于引进绵羊品种,对疾病的抵抗力较弱,除MCH、MCHC和RDW-CV外,无角道赛特羊在血液生化水平上均高于青海本地品种,说明无角道赛特羊是具有高抗病能力的优良品种。本试验为不同绵羊品种机体先天性免疫水平的研究提供了参考数据,对青海藏羊的选育工作和品种改良具有指导意义。     

绵羊高繁殖力候选基因BMPR-IA的研究

以骨形态发生蛋白受体IA（bone morphogenetic protein receptor IA，BMPR-IA）基因为候选基因，采用PCR—SSCP技术检测该基因在高繁殖力绵羊品种（小尾寒羊、湖羊）以及低繁殖力绵羊品种（多赛特羊、特克塞尔羊、德国肉用美利奴羊）中的单核苷酸多态性，同时研究该基因对小尾寒羊高繁殖力的影响。结果表明：在小尾寒羊中检测到AA、AB两种基因型，在湖羊中只检测到一种基因型BB，而在低繁殖力的3个绵羊品种中只检测到一种基因型AA。统计结果表明：小尾寒羊A等位基因频率为0．964，B等位基因频率为0．036。测序结果表明：BB型与AA型相比有6处核苷酸发生了突变。独立性检验表明：外尾寒羊与低繁殖力绵羊品种间基因型分布差异不显著（P〉0．05），而湖羊与小尾寒羊、低繁殖力绵羊品种间基因型分布差异极显著（P〈0．001）。AB基因型小尾寒羊平均产羔数比AA基因型多0．15只，但差异不显著（P〉0．05）。研究表明：BMPR-IA基因不是小尾寒羊和湖羊高繁殖力的主效基因。     

小尾寒羊高繁殖力候选基因RARG的研究

以视黄酸受体γ（retinoic acid receptor-gamma，RARG）基因为候选基因，采用PCR—SSCP技术分析了RARG基因在高繁殖力绵羊品种（小尾寒羊、湖羊）以及低繁殖力绵羊品种（特克塞尔、多赛特、萨福克）中的单核苷酸多态性，同时研究这个基因对小尾寒羊高繁殖力的影响。结果表明：RARG基因引物1扩增片段在5个绵羊品种中存在PCR—SSCP多态性，AA基因型只出现在湖羊中，AB和BB基因型均出现在5个绵羊品种中；BB基因型小尾寒羊平均产羔数比AB基因型多0．41只，但差异不显著（P〉0．05）。RARG基因引物2扩增片段在5个绵羊品种中存在PCR—SSCP多态性，CC和CD基因型均出现在5个绵羊品种中，5个绵羊品种中都没有检测到DD基因型；CC基因型小尾寒羊平均产羔数比CD基因型多0．55只（P〈0．05）。     

Effects of heparin, citrate, and EDTA on plasma biochemistry of sheep: Comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals, but limited information is existing for sheep plasma biochemistry. Ten clinically healthy Baloochi breed of sheep were blood sampled in different tubes containing each anticoagulants and plain tube for harvesting plasma and serum. The concentrations of glucose, cholesterol, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, and magnesium and the activity of aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of GGT, bilirubin and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than that of serum. For corrected citrated plasma significant differences were seen for the concentrations of glucose, creatinine, calcium and the activity of ALP.Most parameters did not show any difference, but significant increase was seen for albumin concentration when heparin was used as an anticoagulant. Using EDTA as anticoagulant caused a significant difference for the concentrations of some of the measured parameters in plasma except glucose, GGT, cholesterol, albumin, bilirubin, CK, and inorganic phosphorus comparing with serum.     

Performance,endoparasitary control and blood values of ewes locally adapted in semiarid region

This study evaluated the variation in the prevalence of endoparasitoses and their impact on body condition and blood values of sheep of the Morada Nova breed. A total of 138 ewes were examined for their morphology (body weight, BW; body condition score, BCS), parasitology (faecal egg count, FEC; Famacha© score; coproculture), hematology (red blood cell count,RBC); hemoglobin concentration, HE; packet cell volume, PCV; mean corpuscular volume, MCV,; mean corpuscular hemoglobin, MCH; mean corpuscular hemoglobin concentration, MCHC; leukocytes, WBC) and serum biochemistry (glucose, cholesterol, triglycerides, urea, creatinine, total protein, albumin, globulin, AST and ALT). Overall the animals presented higher BW and BCS in the months of September and December, however, with high FEC, in addition to a large number of animals with Famacha score 4 and 5. The results showed that the main hematophagous worm affecting the sheep, the genus Haemonchus ssp, appeared in a greater proportion (30–71.66%) than the other worms in all months of the study, except in March. About 30% of the hematological values found in the study are outside the reference ranges for suable sheep e 45.50% for serum biochemistry. These findings demonstrate the most healthy period of the year was from March to June for endoparasites control, however, in the months of September and December the animals showed better performance measures.     

Serum ferritin, serum iron, and erythrocyte values in foals

Twenty-one healthy Thoroughbred and Quarter Horse foals were studied from birth until 1 year of age. Foals had access to an iron-supplemented creep feed before weaning and were fed an iron-supplemented concentrate as part of their diet after weaning at 4 months of age. Initial blood samples were taken before foals were allowed to nurse. Serum iron concentration, total iron-binding capacity, and PCV decreased during the foal's first 24 hours of life. Serum iron concentration decreased rapidly from 446 +/- 16 micrograms/dl (mean +/- SE) at birth to 105 +/- 11 micrograms/dl at 3 days of age. Serum ferritin concentration increased from a mean of 85 +/- 8 ng/ml at birth to 159 +/- 11 ng/ml at 1 day of age. Thereafter, ferritin concentration decreased gradually to a minimum of 61 +/- 6 ng/ml at 3 weeks of age, and then at 6 months increased to values similar to those from reference adult horses. The ferritin concentration in colostrum at birth was 354 +/- 42 ng/ml, compared with 25 +/- 2 ng/ml in milk 1 day later. The decrease and then increase in serum ferritin concentration occurred concomitantly with opposite changes in serum total iron-binding capacity. The mean PCV decreased gradually to a minimum at 3 months of age. This decrease was associated with an increasing number of microcytes, as determined with a cell-size distribution analyzer.     

鸡EX-FABP基因PCR-SSCP分析

以AA白鸡、广西鸡、E1矮小鸡品系为试验材料,采用PCR-SSCP技术对鸡细胞外脂肪酸结合蛋白基因(EX-FABP)的2个片段进行PCR扩增,分析了EX-FABP基因在3个鸡品系的多态性。结果表明:EX-FABP基因在2对引物扩增片段中均存在PCR-SSCP多态性。对于引物1扩增片段,3个鸡品系均检测到BB基因型,AA基因型只出现在AA白鸡中;而且B等位基因频率在3个鸡品系中均明显高于A等位基因频率。对于引物2扩增片段,3个鸡品系均检测到HH和Hh基因型,hh基因型只出现在E1矮小鸡中;H等位基因频率在3个品系中均明显高于h等位基因频率。引物1和引物2的多态性片段测序分析表明,EX-FABP基因第641位点和645位点分别发生了单碱基的转换(G-A和T-C),第3264位点发生了转换(T-C)。     

Renal excretion of urea in the Merino and Steppe fat-tailed breeds of sheep after a short period of fasting

Urea excretion was studied in an experiment with two sheep breeds (steppe fat-tailed and merino) on the second day of fasting when the urea concentration in blood increases in fasting animals. The control group in the two breeds was given free-choice feed and water while fasting sheep were given ad libitum only water. Diuresis in both breeds was steady during the experiment. Glomerular filtration rate was not found to vary, in comparison with the control, although the plasma urea concentration rose in fat-tailed sheep (P less than 0.01) as well as in the sheep of merino breed (P less than 0.001). Fractional excretion of urea decreased in fat-tailed sheep (P less than 0.05) and also in the sheep of merino breed (P less than 0.02) while total output of urea remained steady in fat-tailed sheep but it increased in merino sheep (P less than 0.02). Tubular reabsorption of urea on the second day of fasting was observed to be higher by 65% in merino sheep (P less than 0.001), but in steppe fat-tailed sheep the increase was much higher--by up to 180% (P less than 0.001), in comparison with the control. It was demonstrated by the results that the increased tubular reabsorption of urea contributes to the rise of plasma urea concentration in sheep on the second day of fasting.