Feed restriction delays developmental fast skeletal muscle myosin heavy chain isoforms in turkey poults selected for differential growth.

Genetic selection has been very successful at significantly increasing BW and breast muscle proportion in commercial broiler and turkey strains. The mechanisms of breast muscle growth in poultry and the interactive effects of nutritional status and selection are not fully understood. The hypothesis underlying the current study is that feed restriction, simply as a vehicle for controlling early growth, would delay the temporal expression pattern of neonatal (nMyHC) and adult (aMyHC) fast skeletal muscle myosin heavy chain (MyHC) isoforms in the pectoralis major muscle of turkey poults. The poultry growth model used to evaluate this hypothesis consisted of a randombred control turkey line (RBC2) that represents commercial turkeys of the 1960s and a line developed from the RBC2 by selection for BW at 16 wk of age (F line). The F line has significantly heavier breast muscles than the RBC2 concomitant with increased BW, but the proportion of breast muscle relative to BW is similar. A quantitative indirect ELISA using fast skeletal MyHC isoform specific monoclonal antibodies revealed no significant line differences in the temporal expression of posthatch fast skeletal muscle MyHC in ad libitum fed poults. Feed restriction, however, altered the temporal expression patterns of nMyHC and aMyHC in both F line and RBC2 poults compared with the poults fed ad libitum.

Comparative proteomic characterization of the sarcoplasmic proteins in the pectoralis major and supracoracoideus breast muscles in 2 chicken genotypes.

The selection processes that have resulted in broiler (meat) and leghorn (eggs) chickens have had very different effects on the pectoralis major and supracoracoideus muscles. The objective of this study, therefore, was to analyze the one-dimensional proteomic profiles of sarcoplasmic protein fractions isolated from the p. major and supracoracoideus muscles collected from 10 chicks from each genotype to compare developmental differences. The sarcoplasmic protein fraction was analyzed by SDS-PAGE. The mean band percentages were analyzed using a mixed model, with strain and muscle type as main effects. Six bands were found to be significantly different across the 2 strains. Strain differences in glycogen phosphorylase, enolase, elongation factor 1, creatine kinase, fructose-bisphosphate aldolase, and glyceraldehyde 3-phosphate-dehydrogenase suggest a genotype-specific shift in energy metabolism during breast muscle growth and development.

Multivariate evaluation of 1-dimensional sarcoplasmic protein profile patterns of turkey breast muscle during early post-hatch development.

Proteins are the main participants in metabolic pathways. However, the analysis of protein abundance patterns associated with those pathways is complicated by the large number of proteins involved. In this study, the objective was to present the application of principal component analysis (PCA) to permit the visualization of developmental proteomic patterns of sarcoplasmic proteins found in breast muscle. Different turkey genotypes and nutritional regimens were used to potentially increase the variability within the sarcoplasmic protein profile. Sarcoplasmic protein fractions from turkey breast muscle samples were collected at 6 ages between 7 to 24 d. Breast muscle samples were collected from 2 distinctly different turkey lines. The poults within each line were either ad libitum or restrict fed. Proteomic PCA plots showed a visual developmental pattern from 7 until 17 d. Multivariate ANOVA highlighted the effect of time point and feeding regimen among profile patterns. The use of different genotypes and feeding regimens influenced variability, which was measured by mean Euclidean distances and ellipses of the PCA plots. These treatment effects, however, did not mask the developmental patterns. After 17 d, the proteomic patterns converged, suggesting that a level of biological stability was achieved regardless of the genotype or treatment. The developmental pattern obtained by the PCA methodology can aid in the planning of more efficient experimental designs so the developmental stage of individuals can be more accurately assessed.

(-)-Gossypol containing hen sera and a myosin (-)-gossypol conjugate reduces the proliferation of MCF-7 cells.

Sera from chickens that consumed a known level of (-)-gossypol (-)-GP) exhibited bioactivity against human breast cancer cells in vitro. Based on this, it is conceivable that similar anti-breast cancer activities of different magnitudes will be exhibited in biological samples harvested from (-)-GP-fed layer hens. The experimental data generated in this study may influence the fundamental thinking regarding the utilization of low cost agricultural commodities such as (-)-GP cottonseed meal to produce value-added chemopreventive animal products.

Technical note: a gene delivery system in the embryonic cells of avian species using a human adenoviral vector.

Adenovirus (Ad) has been used in vivo and in vitro as a vector to carry a foreign gene for efficient gene delivery into various cell types and tissues of animals. The aim of the current study was to evaluate the Ad delivery system in primary avian cells. Primary cells isolated from the embryonic pectoralis major muscles of the chicken and quail were cultured and incubated with human recombinant Ad serotype 5 (Ad5) containing sequences encoding either the green fluorescence protein (GFP) gene alone, as a tracking marker, or both GFP and murine 3-hydroxyisobutyryl-CoA hydrolase (mHIBCH) as a target gene. The fluorescent GFP images showed the successful delivery of a target gene using Ad5 in the primary avian cultured cells. In addition, immunostaining of the myosin heavy chain (MyHC) in these cells indicated that a large population of the cells was myogenic. Colocalization of GFP-positive cells with MyHC staining was mostly found in MyHC-negative cells, indicating successful delivery of Ad5 into a large population of mononucleated cells. Furthermore, the current fluorescence study detected the dual expression of GFP and mHIBCH protein in GFP-positive cells. Finally, Western blot analysis confirmed that the Ad-mediated expression of mHIBCH protein was specific in primary cultures of avian myogenic cells and that the mHIBCH protein expression was continued for 15 d after infection in chicken primary cells. These data demonstrate that Ad5 is a feasible tool to express foreign genes in primary cultured cells of avian species, providing a new approach to study the function of genes of interest in muscle development and metabolism.

Myosin heavy chain isoform expression is not altered in the pectoralis major muscle in selenium-deficient chickens recovering from exudative diathetic myopathy.

The recovery of broiler chickens experiencing skeletal muscle myopathy caused by a selenium deficiency was compared with control broiler chickens in an age matched study by ultrastructural analysis of the pectoralis major (PM) muscle and examination of the temporal expression of the developmental fast skeletal myosin heavy chain (MyHC) isoforms. Selenium-deficient chicks showing signs of exudative diathesis (ED) were injected subcutaneously with sodium selenite in water and allowed to recover. At 0, 2, 5, 10, 20, and 30 d after selenium injection, a sample of the PM muscle was removed from selenium-deficient and control chicks for analysis. Ultrastructural analysis revealed vacuolization in the PM of selenium-deficient chicks with little or no visible damage to the sarcomere. Relative amounts of chicken ventricular, embryonic, neonatal, and adult fast skeletal MyHC isoforms were determined using chicken fast skeletal MyHC isoform specific monoclonal antibodies. The temporal expression of the developmental MyHC isoforms was similar in all chickens (P > 0.05). There was no expression of chicken ventricular MyHC observed in the PM of either group. These results indicate that chicken fast muscle recovering from exudative diathetic myopathy does not use the same pathways as chicken skeletal fast muscle regenerating from physical or toxic injury in which temporal expression of the MyHC isoforms is initially predominantly ventricular, then predominantly embryonic, neonatal, and finally predominantly adult developmental MyHC isoform.

Analysis of myosin isoform transitions during growth and development in diverse chicken genotypes.

The temporal expression of chicken skeletal fast myosin heavy chain (MyHC) isoforms in pectoralis major muscle was characterized in 3 commercial broiler lines at embryonic d 19 and at 7, 14, and 21 d posthatch. Lines A and B have been selected for breast yield, and line C is a fast' growing commercial line with limited selection for carcass traits. The isoform transitions in breast muscle samples were compared with samples from Single Comb White Leghorns (line D) using a semiquantitative immunoassay. The hypothesis was that selection for growth and carcass development in broilers would be accompanied by changes in the temporal expression of one or more of the chicken fast MyHC isoforms. Embryos from all lines were sampled at 19 d of incubation, and chicks were randomly sampled at 7, 14, and 21 d post-hatch. Myosin was extracted from pectoralis major muscle and assayed for purity and total protein concentration by SDS-PAGE and bincinchoninic acid protein analyses, respectively. The relative concentration of MyHC isoforms was evaluated by semiquantitative ELISA with 3 monoclonal antibodies specific for chicken skeletal fast embryonic and adult (eMyHC, aMyHC; EB165), neonatal (nMyHC; 2E9), and adult (aMyHC; AB8) myosin, respectively. The overall temporal expression of the myosin isoforms, eMyHC, nMyHC, and aMyHC, was similar in all lines. With eMyHC, at 19 d of incubation, line B had lower expression than lines A, C, and D. Expression of nMyHC, in lines C and D was similar with expression being highest at 7 d and lower at 14 d and 21 d. In lines A and B, however, nMyHC expression was higher at hatch than lines C and D. In line D, aMyHC was expressed at 14 d and increased through 21 d, whereas in lines A, B, and C, aMyHC isoform was expressed and was higher at 7 d and increased through 21 d. The results of this experiment support our hypothesis that commercial broilers have different temporal expression patterns of the developmental chicken fast MyHC isoforms.

A comparison of growth and development patterns in diverse genotypes of broilers. 1. Male broiler growth.

Selection for breast muscle yield and BW in commercial broilers has resulted in genotypes far different from broilers processed in the past. When comparative studies with commercial lines are conducted, it is often difficult to differentiate between carcass effects resulting from direct genetic selection vs. correlated effects that partially reflect genetic changes in BW. The objective of the present experiment was to compare growth and development characteristics of male broilers from commercial lines exhibiting similar rates of BW gain based on a percentage of 8-wk BW but exhibiting different carcass traits. Male broilers from 2 commercial genotypes exhibiting increased breast muscle yield (A and B) were compared with broilers from a commercial line that was "unimproved" with respect to conformation (C). All birds were fed a commercial-type broiler starter diet throughout the study and were processed at 8 wk of age for carcass comparisons. No differences were observed among lines for breast-free BW or weight of the abdominal fat pad. The absolute and relative weights of pectoralis major and pectoralis minor breast muscles were heavier in lines A and B than C (P < 0.001). Length (C > A > B; P < 0.001), width (B > C >A; P < 0.001), and depth (A = B > C; P < 0.001) of the pectoralis major were different between lines. Drum and thigh weights were heavier in lines A and B than C (P < 0.001). There were genotype differences in tibia length (C > A = B, P < 0.001) and femur length (C > A = B, P < 0.001). The comparison of line C with selected lines A and B, suggested that line C may provide a useful model for studying carcass development between commercial genotypes with similar growth patterns.

A comparison of growth and development patterns in diverse genotypes of broilers. 2. Pullet growth.

Genetic selection within commercial broiler lines continues to generate improvements in BW, feed conversion, and breast meat yield. The objective of the current experiment was to compare carcass and reproductive characteristics of broiler breeder pullets from 2 dam lines that produce heavy broilers with increased breast yield (A and B) with pullets from a commercial line that does not have the extremes in breast yield (C). Restricted-fed BW were similar at all ages of the experiment in the 3 genotypes. All pullets were photostimulated at 23 wk of age, and carcass and reproductive tract measurements were made at 27 wk of age. There were no differences in BW among the lines at 27 wk of age, but the weights of the pectoralis major and minor breast muscles were heavier in lines A and B compared with line C (P < 0.001). The weight of the abdominal fad pad, however, was heavier in line C (P < 0.04). There was no difference in total drum weight or total thigh weight among lines A, B, or C. Tibia length and tibia width were similar in lines A and C, and the measurements were larger in these lines than in line B (P < 0.02). Femur length was longer (P < 0.001) in line C than in lines A and B, whereas femur width was greater in line C than in line A (P < 0.001) but similar to line B (P < 0.001). Oviduct weight was greater in line C compared with lines A and B (P < 0.004), but there were no differences in total ovarian weight, follicle number, or follicle weight. The information gathered in the present experiment suggested that line C may prove to be useful for reproductive comparisons with commercial lines exhibiting significant differences in carcass traits.

Effect of selection for growth on onset of sexual maturity in randombred and growth-selected lines of Japanese quail.

An experiment was conducted to determine the effect of selection for growth (BW) on the onset of reproduction (first egg) in Japanese quail hens from growth-selected (HW) and randombred (R1) lines. The HW line had undergone over 40 generations of selection for increased 4-wk BW and was originally developed from the R1 line. Data were collected over two consecutive hatches and summarized by hatch and within lines. Body weight at 35 d of age was positively correlated with BW at sexual maturity (first egg) in both the R1 and HW lines, but these correlations were not significant in both hatches for either line (Hatch 1-R1; Hatch 2-HW; P < or = 0.05). There was a negative correlation between age at sexual maturity (days to first egg) and 35 d BW in both lines with the exception of the HW hens in Hatch 2. Age at sexual maturity and BW at sexual maturity was positively correlated (P < or = 0.001) in the R1 line but did not show the same relationship in the HW line. Age at sexual maturity and weight of the abdominal fat pad were positively correlated in the R1 line (Hatch 1, P < or = 0.01; Hatch 2, P < or = 0.001), but this relationship was not significant in the HW line. Age at sexual maturity and follicle number was negatively correlated in both lines but was not significant in Hatch 2 of the HW line. Follicle size, however, was positively correlated with days to first egg in only Hatch 2 (P < or = 0.001) of the HW line. The data suggest that the relationships between the onset of sexual maturity and both reproductive parameters and carcass traits in hens from consecutive hatches of HW quail are less clear than in the R1 line.

Biochemical analyses of muscles from poultry bred for rapid growth.

In the current study, commercial broiler breeder hens were mated with either commercial broiler breeder males (B/B) or artificially inseminated with semen from Leghorn cockerels (B/L). Embryos and chicks from each mating were used to study the effects of paternal genotype on breast muscle myosin expression without the confounding effects of differences in egg size and embryo development due to maternal genotype. Specifically, the temporal transitions of myosin heavy chain (MyHC) isoforms within the pectoralis (P.) major and P. minor were measured. The relative concentration of the embryonic MyHC isoform increased from d 17 through 21 in ovo in both genotypes and was higher in B/B embryos than in B/L embryos (P < or = 0.01). At 21 d posthatch, there was an increased proportion of the adult MyHC isoform within the P. major and P. minor in B/B compared with B/L chicks (P < or = 0.01). This result suggests that the B/B chicks were making the transition to mature skeletal muscle more rapidly than the B/L chicks. Although samples taken from the P. minor of B/B and B/ L chicks exhibited an increased proportion of the adult MyHC isoform and lower proportion of the neonatal MyHC isoform at 21 d, the genetic differences were far more pronounced in the larger P. major (P < or = 0.01). In summary, the P. major from the faster growing B/B chicks exhibited earlier temporal transitions of developmental fast MyHC, and these differences were evident as early as 17 d in ovo.

Analysis of poultry fertility data. 3. Analysis of the duration of fertility in naturally mating Japanese quail.

The purpose of the present study was to test the appropriateness of iterative least squares regression for the evaluation of fertility data in naturally mating quail. In each of four trials, 20 male and 200 female randombred Japanese quail were housed in stacked breeder cages. Paired females were exposed to their assigned male for a single 48-h period. Eggs were collected for 2 wk following removal of the male, incubated, and fertility determined by visual inspection at egg breakout. In Trials 1 and 3, sexually experienced males were placed with experienced and inexperienced females, respectively. In Trials 2 and 4, inexperienced males were placed with experienced and inexperienced females, respectively. Duration of fertility, by male, was analyzed by iterative least squares, using the model y(x) = gamma/(1 + e beta(tau - x)). Overall fertility was analyzed with a log odds model following transformation to logits. Iterative least squares provided estimates of fertility duration of 3.75 to 9.18 d, with significant (P < 0.05) differences in the duration of fertility observed between individual males as well as between the trials. Differences (P < 0.05) in overall fertility (17.7 to 58.3%) were also observed, with inexperienced males paired with experienced females exhibiting the lowest overall means. Taken together, these results suggest that iterative least squares may be used to evaluate fertility in naturally mating populations and that reproductive experience can have a profound effect on the interpretation of fertility in naturally mating quail.

Causes of increased renal echogenicity in pediatric patients.

Review of 2,700 abdominal ultrasonic examinations revealed 56 patients whose kidneys showed increased echogenicity. Echogenic kidneys were associated with medical renal disease in 94% of cases (30% glomerular, 48% tubulointerstitial, 16% end-stage) and with no detectable renal disease in 6% (three patients). Patterns of increased echogenicity and renal size were evaluated. Specific patterns occurred in end-stage renal disease and polycystic kidney disease. Other medical renal diseases had overlapping ultrasonographic features. Some generalizations could be made although increased echogenicity was often nonspecific.

Cystic fibrosis: its characteristic appearance on abdominal sonography.

The abdominal sonograms of 24 patients with cystic fibrosis aged 8-30 years were reviewed. Most patients had abnormal scans; the number and severity of organs involved tended to increase with age. When the pancreas was identified, it was usually echogenic and small. Cholelithiasis, microgallbladder, and obstruction of the common bile duct were observed. Textural changes in the liver reflected underlying parenchymal disease; splenomegaly and portal hypertension occurred in responses to severe hepatic involvement. A few patients had thick gastric or duodenal wall.

Huge splenic cyst in a newborn: comparison with 10 cases in later childhood and adolescence.

Radiographic, sonographic, and histologic findings in a case of a huge splenic cyst in a newborn are presented. The patient had the characteristic findings, particularly the visceral displacement, associated with splenic cysts in a series of 10 older children and adolescents. The occurrence in a newborn of a large splenic cyst histologically similar to those found in older children supports the hypothesis that they are developmental rather than traumatically acquired.