Polymorphisms in the promoter region of myostatin gene are associated with carcass traits in pigs.

Higher average daily gain, more lean meat yield and less fat yield of porcine carcass increase selling profits for animal producers. Myostatin (MSTN), previously called GDF8, is a member of transforming growth factor-ß (TGF-ß) superfamily. It is a negative regulator for both embryonic development and adult homeostasis of skeletal muscle. In this study, the genotypes of the previously described SNPs MSTN g.435G>A and g.447A>G SNPs in 66 Duroc pigs, 33 Landrace pigs, 180 Duroc × Landrace (DL) pigs and 155 Duroc × Yorkshire × Landrace (DYL) pigs were determined by Taqman SNP Genotyping Assays. For Duroc and Landrace pigs, MSTN g.435GG/g.447AA individual had greater backfat thickness (p < 0.05) than g.435AA/g.447GG individual, whereas MSTN g.435AA/g.447GG had greater meat (p < 0.05) and meat percentage (p < 0.05) than g.435GA/g.447AG individual. For DL and DYL pigs, the MSTN g.435GG/g.447AA animals were greater in backfat at ultrasound 10th rib (p < 0.05) and carcass 10th rib (p < 0.01) than g.435AA/g.447GG individual. The MSTN g.435AA/g.447GG individual also had higher values than g.435GG/g.447AA for anterior-end meat (p < 0.05), posterior-end meat (p < 0.01), total meat weight (p < 0.01) and meat percentage (p < 0.01). This study confirmed evidence that MSTN g.435G>A and g.447A>G affected carcass traits in pigs. The effects of the mutated alleles were additive with the maximal effects resulting from two copies of the mutated allele. Selection for MSTN g.435A/g.447G allele is expected to increase muscle of limb and total meat production and decrease backfat thickness.

Bimolecular triplex formation between 5'-d-(AG)nT4(CT)n and 5'-d-(TC)n as functions of helix length and buffer.

It was observed that a group of unusually stable DNA hairpins (Hn: 5'-d-(AG)nT4(CT)n, n = 2-4) were directed to homopyrimidine sequences (Pn: 5'-d-(TC)n) by py x pu x py-type triplex formation, resulting in high binding affinity and specificity. The spectroscopic results (UV and CD) showed that the short bimolecular triplex Hn:Pn could be formed in acidic conditions (pH 4.5-6.0) as helix length n > 2, and further extending to neutral pH as n = 4. This hairpin strategy for recognition of a pyrimidine strand has a substantial binding advantage over either the conventional linear analog or simple Watson-Crick complement. Triplex stability of Hn with Pn is not only pH-dependent, as expected for triplexes involving C+. GC triads, but also sensitive to the buffer. The triplex H4:P4 was formed in the phosphate buffers of pH 6.0-7.0 but already dissociated above pH 6.5 in the buffer of cacodylate, MOPSO or PIPES. By contrast, the nature of a buffer had no major influence on stability of a hairpin duplex. Here we provide a simple triplex system, and the data presented here may be useful in defining the experimental conditions necessary to stabilize triplex DNA.

Genetic evaluation by BLUP in two-breed terminal crossbreeding systems under dominance.

To obtain estimates of breeding values by BLUP using Henderson's mixed-model equations, it is necessary to invert the covariance matrix for each random effect in the model. In a model in which the genotypic value is included as a random effect (genotypic model), it is necessary to invert the genotypic covariance matrix. Under additive inheritance, the inverse of the genotypic covariance matrix can be computed efficiently. Under dominance inheritance, however, an efficient method to invert the genotypic covariance matrix has not yet been developed, especially for crossbred populations. Thus, the use of a genotypic model for BLUP is not suitable for genetic evaluation in large, crossbred populations. We present an equivalent model in which the genotypic effect is partitioned into additive and dominance effects. With this equivalent model, methods used for within-breed genetic evaluation by BLUP can be used for a two-breed terminal cross under dominance.

Theory for modelling means and covariances in a two-breed population with dominance inheritance.

This paper presents theory and methods to compute genotypic means and covariances in a two breed population under dominance inheritance, assuming multiple unlinked loci. It is shown that the genotypic mean is a linear function of five location parameters and that the genotypic covariance between relatives is a linear function of 25 dispersion parameters. Recursive procedures are given to compute the necessary identity coefficients. In the absence of inbreeding, the number of parameters for the mean is reduced from five to three and the number for the covariance is reduced from 25 to 12. In a two-breed population, for traits exhibiting dominance, the theory presented here can be used to obtain genetic evaluations by best linear unbiased prediction and to estimate genetic parameters by maximum likelihood.

Study on the partial purification of gonadotropins and thyrotropin from deer (Cervus elaphus) pituitaries.

Deer pituitaries were extracted with Tris-Cl buffer and the extract was fractionated on Concanavalin A-Sepharose into an unadsorbed ConA I fraction and an adsorbed ConA II fraction. The ConA II fraction was chromatographed on CM-cellulose to yield an unadsorbed CM I fraction and an adsorbed CM II fraction. The CM I and CM II fractions were then respectively subjected to ion exchange chromatography on DEAE-cellulose to give the resultant unadsorbed DEAE I and adsorbed DEAE II fractions. The ConA II CM II DEAE I fraction was the chromatographic fraction with the highest potency in stimulating testosterone production by isolated rat Leydig cells and the highest immunoreactivity in a rat luteinizing hormone (LH) radioimmunoassay (RIA). The ConA II CM II DEAE II fraction represented the fraction enriched in thyroid stimulating hormone (TSH). It exhibited cross reactivity in a rat TSH RIA and much lower LH bioactivity than the LH-enriched ConA II CM II DEAE I fraction. The ConA II CM I DEAE II fraction represented the follicle stimulating hormone (FSH)-enriched fraction. The ConA I fraction demonstrated negligible FSH immunoreactivity and LH bioactivity, indicating that most of deer FSH and LH were adsorbed on ConA-Sepharose.

Covariance between relatives in multibreed populations: additive model.

Covariance between relatives in a multibreed population was derived for an additive model with multiple unlinked loci. An efficient algorithm to compute the inverse of the additive genetic covariance matrix is given. For an additive model, the variance for a crossbred individual is a function of the additive variances for the pure breeds, the covariance between parents, and segregation variances. Provided that the variance of a crossbred individual is computed as presented here, the covariance between crossbred relatives can be computed using formulae for purebred populations. For additive traits the inverse of the genotypic covariance matrix given here can be used both to obtain genetic evaluations by best linear unbiased prediction and to estimate genetic parameters by maximum likelihood in multibreed populations. For nonadditive traits, the procedure currently used to analyze multibreed data can be improved using the theory presented here to compute additive covariances together with a suitable approximation for nonadditive covariances.

Gonadotropin bioactivities in mouse, hamster, rat and guinea pig pituitaries are largely adsorbed on concanavalin A-sepharose.

The pituitaries of mice, hamsters, guinea pigs and rats were extracted with Tris-Cl buffer and the extracts were chromatographed on Concanavalin A (ConA)-Sepharose into unadsorbed ConA I and adsorbed ConA II fractions. The ConA I fraction was subjected to gel filtration on Sephadex G-100 and fractionated into an unretarded peak and several retarded peaks. The peak with a molecular weight of approximately 40,000 (designated ConAI Sephadex fraction II) was then subjected to ion exchange chromatography on CM-cellulose and fractionated into an unadsorbed CM I and an adsorbed CM II fraction. The ConA II fraction was fractionated by ion exchange chromatography on CM-cellulose into CM I and CM II fractions. The ConA II CM II fraction was the chromatographic fraction which exhibited the highest potency in stimulating testosterone production by isolated rat Leydig cells. Its activity was much higher than the corresponding ConA I Sephadex fraction II CM II fraction which differed chromatographically only by non-adsorption on ConA-Sepharose. The ConA II CM II fraction manifested cross reactivity in a rat luteinizing hormone (LH) radioimmunoassay. The guinea pig pituitary ConA II CM II fraction also cross-reacted in a rat thyroid stimulating hormone radioimmunoassay. The ConA II fractions of hamster and guinea pig pituitary extracts demonstrated follicle stimulating hormone (FSH) activity while the corresponding ConA I fractions did not. The results suggest that the ConA II/ConA II CM II fraction contained most of the FSH and LH activities present in the pituitary extract.

An embryo transfer study of reciprocal cross differences in growth and carcass traits of Duroc and Landrace pigs.

Reciprocal cross differences have been reported for growth rate and carcass traits in F1 pigs with the Duroc (D) as a parent breed. Such differences are synonymous with maternal effects if effects of sex linkage and genomic imprinting are negligible. In the present study, transfer of embryos (ET) to paternal breed recipients partitioned effects occurring at or before fertilization from postfertilization effects for growth and carcass traits in F1 D-Landrace (L) pigs. Fifteen boars sired 115 F1 litters, 49 produced by ET. Growth rate of 349 barrows and 361 gilts and carcass measurements on 256 barrows and 159 gilts were analyzed assuming mixed linear models with animal and litter as random effects. Contrasts among genotype (D x L, L x D)- treatment (ET, non-ET) means were tested. Reciprocal cross differences were not detected for growth rate or for carcass weight, length, average backfat thickness, estimated carcass lean, or lean per day of age. Reciprocal cross differences for 10th rib backfat thickness (BF) and longissimus muscle area (LMA) were detected only in barrows. The sexual dichotomy for reciprocal cross differences followed expectations for a Y-linked gene(s), consistent with the fact that reciprocal D-L crossbred barrows exhibited a paternal effect, with responses more like the sire breed than the dam breed. Barrows that were non-ET from D sires and L dams had 3.9 cm2 larger LMA and 5.8 mm less BF than barrows from L sires and D dams (P less than .001). Barrows from ET sired by D boars had 3.8 cm2 larger LMA than did barrows from ET sired by L boars (P less than .001), although no difference was detected for BF. Barrows sired by D boars reared in a D postfertilization environment (ET) had 6.2 cm2 greater LMA and 4.1 mm less BF (P less than .05) than barrows sired by L boars gestated and reared by D dams (non-ET). Barrows sired by D boars reared by L dams (non-ET) had 1.5 cm2 greater LMA and 2.3 mm less BF (P greater than .10) than barrows sired by L boars reared by L dams (ET). In conclusion, reciprocal cross differences detected for BF and LMA in barrows were established before or at fertilization and seemed to be Y-linked.

Genetic analyses of growth, real-time ultrasound, carcass, and pork quality traits in Duroc and Landrace pigs: I. Breed effects.

Knowledge of breed effects on carcass and pork quality traits is required to develop commercial crossbreeding programs that emphasize product quality. A 2 x 2 diallel mating system involving Landrace and Duroc pigs was used to estimate individual heterosis, direct breed effects and reciprocal cross differences for post-weaning growth, real-time ultrasound, carcass, and pork quality traits. Data from 5,649 pigs and 960 carcasses representing 65 and 49 sires, respectively, were analyzed assuming animal models. Duroc-sired pigs had 2.1 cm shorter carcasses with 7.3 mm less 10th rib backfat (BF), 4.4 cm2 larger longissimus muscle area (LMA), yielded 2.1 kg more estimated fat standardized lean (FSL), gained 16.5 g more estimated lean per day of age (LDOA), and had 1.0% less water (PWAT) and 1.9% more intramuscular fat (IMF) in the longissimus muscle than did Landrace-sired pigs (P less than .01), adjusted to an off-farm live weight of 111 kg. Reciprocal cross differences were detected for BF, LMA, FSL, LDOA and for subjective marbling, firmness, and muscling scores (P less than .01). Durocsired F1 barrows had 6.3 mm less BF and 5.9 cm2 larger LMA, yielded 3.2 kg more FSL, gained 22.3 g more LDOA, and had less marbling in the longissimus muscle and heavier ham muscling than reciprocal cross barrows. Heterosis estimates (P less than .05) were 27.6 g/d (3.2%) for ADG, -5.8 d (-3.6%) for off-test age, 2.7 cm (3.4%) for carcass length, 1.5 kg (7.2%) for FSL, 14.7 g (5.7%) for LDOA, -.07 (-3.6%) for muscle color, -.5% (-13.2%) for IMF, and .3% (.3%) for PWAT. Breed effects were not detected (P greater than .10) for muscle pH, cooking loss, shear value, and water-holding capacity or for eating quality traits. Reciprocal cross differences suggest an advantage in using the Duroc as a terminal sire, but improved carcass composition and higher intramuscular fat did not seem to affect eating quality traits.

Genetic analyses of growth, real-time ultrasound, carcass, and pork quality traits in Duroc and Landrace pigs: II. Heritabilities and correlations.

Knowledge of the genetic control of pork quality traits and relationships among pork quality, growth, and carcass characteristics is required for American swine populations. Data from a 2 x 2 diallel mating system involving Landrace and Duroc pigs were used to estimate heritabilities and genetic correlations among growth (ADG), real-time ultrasonic (US) measures of backfat thickness (BF) and longissimus muscle area (LMA), carcass characteristics, and various pork quality traits. Data were collected from 5,649 pigs, 960 carcasses, and 792 loin chops representing 65, 49, and 49 sires, respectively. Genetic parameters were estimated by REML assuming animal models. Heritability estimates were moderate to high for ADG, USBF, USLMA, carcass BF, and LMA, percentage of LM lipid (IMF), pork tenderness, and overall acceptability. Estimates were low to moderate for percentage of cooking loss, pH, shear force, percentage of LM water, water-holding capacity (WHC), pork flavor, and juiciness. Genetic correlations between US and carcass measures of BF and LMA indicate that selection based on US data will result in effective improvement in carcass characteristics. Selection for increased LMA and(or) decreased BF using US is, however, expected to result in decreased IMF and WHC, increased percentage of LM water and shear value, and in decreased juiciness, tenderness, and pork flavor. Average daily gain was favorably correlated with IMF and unfavorably correlated with shear force. Selection for increased ADG is expected to improve WHC but to decrease the percentage of LM water, with an associated decrease in juiciness. The results of this study suggest the feasibility of including meat quality in selection objectives to improve product quality. Favorable genetic correlations between IMF and eating quality traits suggest the possible merit of including IMF in the selection objective to improve, or restrict change in, pork eating quality.

A study of operator effects on ultrasonic measures of fat depth and longissimus muscle area in cattle, sheep and pigs.

Use of real-time ultrasonography in meat animal improvement programs has increased largely as a result of the perceived accuracy of such instruments in measuring longissimus muscle area (LMA) and fat depth (BF). The objective of this study was to examine operator effects for ultrasonic determination of BF and LMA in market-weight cattle, sheep and pigs. The day prior to slaughter, five persons scanned 45 pigs, 32 sheep and 18 cattle at the last rib using an A-mode Ithaco Model 731AM101 body composition meter (ABF) and a Johnson and Johnson Ultrasound 210DX B-mode scanner fitted with a 3.0 MHz probe. All operators measured their own B-mode recordings (OBF, OLMA); an independent, experienced technician also obtained measurements from all recordings (TBF, TLMA). Species x machine x operator interaction effects were detected (P less than .001) for ultrasonic BF. Within-species analyses also revealed that the machine x operator interaction was important (P less than .001) for all species. Analyses of ABF, OBF, TBF, OLMA and TLMA detected species x operator interactions (P less than .001) for all traits except TLMA (P less than .20). Assuming a random model with animal, operator and residual effects, variance components were estimated by maximum likelihood for each species. Repeatabilities, calculated as the intraclass correlation among animals for BF and LMA scanned and interpreted by different operators, were .13, .21 and .51 (OBF) and .28, .15 and .29 (OLMA) for cattle, sheep and pigs, respectively, indicating the importance of operator effects. Repeatabilities of TBF were .90, .42 and .68 and of TLMA were .19, .55 and .65 for cattle, sheep and pigs, respectively, indicating the importance of image interpretation in determining operator effects associated with use of the 210DX B-mode scanner. Technical training standards must, therefore, be established for operators of such equipment.

Inhibitory actions of pineal indoles on steroidogenesis in isolated rat Leydig cells.

The inhibition elicited by pineal indoles on testosterone production by isolated rat Leydig cells could not be overcome by a maximally active dose of luteinizing hormone (LH), and dibutyryl-cAMP-induced steroidogenesis was also suppressed, suggesting that the indoles did not exert their effect through an interaction with LH receptors on Leydig cells. Pregnenolone-induced progesterone secretion was unaffected, indicating that the activity of 3 beta-dehydrogenase was not altered. Methoxytryptamine (MTN) at a dose of 1 mM decreased progesterone-induced 17 alpha-hydroxyprogesterone secretion by 50%, suggesting that the enzyme 17 alpha-hydroxylase was inhibited. The inhibition caused by other pineal indoles was either very slight or absent. MTN reduced 17 alpha-hydroxyprogesterone-induced androstenedione production by 65%, methoxytryptophol (MTOL) and melatonin (MEL) by 35%, and methoxyindoleacetic acid (MIAA) and hydroxyindoleacetic acid (HIAA) by 10%, revealing an inhibition of 17-20 desmolase. The reduction of androstenedione-induced testosterone production by MTN infers inhibition of 17-ketoreductase activity. However, testosterone production induced by either dehydroepiandrosterone or androstenedione was unaffected by other indoles. The data suggest that MTN inhibited 17 alpha-hydroxylase, 17-20 desmolase, and 17-ketoreductase while MEL, MTOL, MIAA, and HIAA inhibited only 17-20 desmolase. The highest potency of MTN in inhibiting enzymes on the testosterone biosynthestic pathway was reflected in its greatest inhibition of testosterone production. On the other hand, MIAA and HIAA had the lowest potency in inhibiting the enzymes and testosterone production while MEL and MTOL had intermediate potencies.

Studies on IUD-induced menorrhagia and increased synthesis of prostacyclin in endometrium.

PIP: 43 samples of endometrium from IUD users with excessive uterine bleeding (MBL 80 ml), normal menstrual blood loss (MBL 80 ml), and non-IUD users with normal menstrual blood loss (80 ml) have been studied. Concentration of 6-keto-PGF1alpha, a metabolite of prostacyclin (PGI2), was determined by radioimmunoassay. It was found that the concentration of 6-keto-PGF1alpha of patients with IUD-induced excessive uterine bleeding was significantly higher than that of IUD users with MBL 80 ml (p 0.05) and of non-IUD users (p,0.01). But the difference between IUD users with normal menstruation and the controls was of no statistical significance (p0.05). The results also indicated a positive correlation between the amount of MBL and 6-keto-PGF1alpha concentration in the endometria of IUD users (r=0.439; p0.05). The measurements of both tissue plasminogen activation (t-PA_ and 6-keto-PGF1alpha concentrations from samples of 28 cases showed a weak positive correlation between t-PA and 6-keto-PGF1alpha (r=0.459; p0.05). Further study is necessary to evaluate the significance of this result. These studies prove that the increased 6-keto-PGF1alpha is an important factor in the existence of excessive uterine bleeding in IUD users.^ieng

Carp maturational-ovulatory gonadotropin but not carp vitellogenic gonadotropin or salmon maturational-ovulatory gonadotropin stimulates testosterone production by rat Leydig cells in vitro.

Carp (Cyprinus carpio) maturational-ovulatory gonadotropin, prepared from the fraction of pituitary extract adsorbed on Con A-Sepharose (Con A II) and subsequently adsorbed on CM-cellulose (Whatman CM-52), stimulated testosterone production by isolated rat Leydig cells. The fraction of carp pituitary extract unadsorbed on the immobilized lectin (Con A I) with a mol. wt of 30,000, which had previously been shown to contain vitellogenic gonadotropin, was devoid of steroidogenic activity. Salmon (Oncorhynchus keta) pituitary Con A I and Con A II fractions containing vitellogenic and maturational-ovulatory gonadotropin respectively did not enhance steroidogenesis in the same assay system. The results indicated that carp maturational-ovulatory gonadotropin resembled mammalian luteinizing hormone (LH) in its chromatographic behavior on Con A-Sepharose and CM-cellulose and also in its steroidogenic activity in rat Leydig cells. However, not all teleost maturational-ovulatory gonadotropins are LH-like: the salmon hormone is a notable exception. The data further supports the distinctiveness of carp vitellogenic gonadotropin and maturational-ovulatory gonadotropin.