Biomedical subjects

N B Anthony

Publications and source records attributed to N B Anthony.

At least 37 records · Page 2Linked to original sources

PubMed1998

Flow-dependent pulmonary vasodilation during acute unilateral pulmonary artery occlusion in Jungle Fowl.

Giant Jungle Fowl previously were shown to be highly resistant to the onset of pulmonary hypertension syndrome (PHS, ascites) under conditions that induce a substantial incidence of PHS in broiler chickens. In the present study, lightly anesthetized, clinically healthy 12- to 13-wk-old male Giant Jungle Fowl maintained a lower respiratory rate, a similar hematocrit, and superior arterial blood gas values when compared with 6-wk-old male broilers. Giant Jungle Fowl weighed less than broilers (1,860 +/- 19 vs 2,788 +/- 63 g, respectively) and had equivalent absolute values for pulmonary arterial pressure, cardiac output, and pulmonary vascular resistance. Acute unilateral pulmonary artery occlusion in Giant Jungle Fowl doubled the pulmonary vascular resistance and forced the right ventricle to propel a sustained 60% increase in blood flow through the vasculature of the unoccluded lung. A transient increase in pulmonary arterial pressure initially was required to overcome the vascular resistance of the unoccluded lung; however, flow-dependent vasodilation gradually reduced the pulmonary vascular resistance and permitted pulmonary arterial pressure to return toward control levels. Unilateral pulmonary artery occlusion also triggered an immediate reduction in the partial pressure of oxygen in arterial blood, and the gradual return of pulmonary arterial pressure toward control levels did not eliminate this ventilation-perfusion mismatch, which has been attributed to blood flowing too rapidly through the unoccluded lung to permit diffusive gas equilibration. The inherent capacity for flow-dependent pulmonary vasodilation may reduce the susceptibility of Giant Jungle Fowl to PHS by reducing the increment in pulmonary arterial pressure required to propel an elevated blood flow through the lungs.

Animals↗

PubMed1998

Effects of amino acid restriction during starter and grower periods on subsequent performance and incidence of leg disorders in two strains of male large white turkeys.

Male turkeys of two commercial Large White strains (Nicholas 88, BUT 6) were subjected to growth restriction by means of reducing amino acid (AA) content of diets to a minimum of 75% of NRC (1994) suggested levels. There were three periods when diets containing 75% of NRC recommended AA for that age period were fed ad libitum: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth (control) group was not restricted in AA content at any time. When turkeys were not fed the AA-restricted diets they were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1994) AA recommendations, which resulted in a 3 x 4 factorial arrangement of treatments with three AA levels by four restriction times. Four pens of 12 males each were fed each AA by restriction time combination. At 18 wk, all birds were scored individually for leg condition and representative samples of turkeys were processed for parts yield. Birds fed restricted diets from 0 to 6 or 6 to 12 wk had significantly lower BW at 18 wk than control birds. Birds fed the restricted diets from 0 to 3 wk did not differ significantly in 18-wk BW compared to control birds but the magnitude of difference was similar to that observed at the end of the restriction period. Feed utilization was not improved by early AA restriction. Restricting early growth resulted in a significantly higher incidence of birds with no leg disorders and a lower incidence of birds with moderate leg disorders than control birds. Feeding higher AA levels during realimentation resulted in a greater severity of leg disorders. Breast meat yield was depressed significantly as severity of early restriction increased. Increasing dietary AA above NRC (1994) recommended levels generally improved performance during realimentation but was not able to compensate for reduced gains during restriction.

Amino Acids↗

PubMed1997

Effect of intermittent activity on broiler production parameters.

The use of intermittent lighting in broiler production has been shown to result in spurts of activity that appear to reduce lameness. Because intermittent lighting is difficult to achieve in curtain-sided houses, the objective of this study was to determine whether simple equipment used to increase activity in broilers would improve production variables. At 1 d of age, 840 male broiler chicks were placed in 24 floor pens. The four treatments (six replicates of 35 chicks each) were as follows: 1) Control-standard feeders, 2) Ramps and Toys-birds had to climb a slight incline ramp to reach feeder and had a hanging mobile, 3) Ramps only, and 4) Toys only-standard feeders. Two trials were conducted. Weekly group weights and feed consumption were recorded. Mortality was recorded daily. At 6 wk of age, birds were bled, euthanatized, weighted, and scored for ascites and tibial dyschondroplasia (TD), and relative heart, liver, and spleen weights were obtained. Blood samples were analyzed for blood gases, hemoglobin, red blood cell count, and clinical chemistries were performed. In Trial 1, during Weeks 2, 3, and 4, treatments with ramps had significantly heavier average bird weight and significantly lower feed:gain ratios. In Trial 2, treatments with ramps had no difference in average BW; however, these groups consumed less feed, resulting in significantly lower feed:gain ratios. Cumulative mortality was decreased by ramp treatment in Trial 2. Toys decreased the incidence and severity of TD in Trial 2. In general, organ weights, blood gases, hematologies, and clinical chemistries were not affected by treatments. However, birds in treatments with ramps had significantly lower serum calcium and smaller hearts in Trial 1, and significantly lower serum cholesterol and smaller hearts in Trial 2.

Animal Husbandry↗

PubMed1997

Response of two strains of large white male turkeys to amino acid levels when diets are changed at three- or four-week intervals.

A study was conducted to evaluate the amino acid recommendations of the NRC (1994) when diets were changed at 3- or 4-wk intervals. Diets formulated to provide from 90 to 115% of recommended amino acid levels were fed to Nicholas (NIC) and British United Turkey (BUT) Large White males from day-old to 24 wk of age; samples of turkeys were processed at 18 and 24 wk. Results indicated that the amino acid levels suggested by NRC are adequate to support maximum body weight gain, feed conversion, and dressing percentage of Large White males grown to 18 or 24 wk when fed on 4-wk intervals. An approximately 5% higher level of amino acids was required to maximize breast yield. When feeds were changed at 3-wk intervals, higher levels of amino acids were required to maximize performance; however, there did not seem to be any difference in the response of the two strains of turkeys to different levels of amino acids in this study.

Amino Acids↗

PubMed1997

Ornithine decarboxylase activity in muscle, liver, and intestinal tissue of turkeys during a short-term feed withdrawal and following refeeding.

The activity of ornithine decarboxylase (ODC), an enzyme associated with cellular growth and protein synthesis, was examined in breast muscle, liver, and intestinal tissues of turkeys during a short-term period of feed withdrawal (FW) and following refeeding. Turkeys from a randombred control line were reared under standard management practices to 3 wk of age in battery brooders. Feed was then withdrawn from FW birds for a 48-h period, after which feed was consumed ad libitum. Control birds consumed feed ad libitum throughout the test period. Tissues were collected from 12 birds per treatment following 24 and 48 h of FW and at 6, 12, 24, and 48 h following refeeding for later determination of tissue ODC activity. Activity of ODC was greater in tissue from the small intestine than in liver tissue and both had greater activity than that exhibited by breast muscle. Short-term FW and refeeding produced differential responses in ODC activity of the three tissues examined. Feed withdrawal resulted in a reduction of ODC activity in intestinal tissue, whereas activity was unaffected for liver or breast muscle tissues. Compensatory increases in ODC activity were observed in liver and intestinal tissues; however, the increase was both more rapid and transitory in small intestine than in liver tissue. The ODC activity in breast muscle was largely unaffected by short-term FW and refeeding. Patterns of ODC activity in liver during FW and refeeding closely resembled patterns observed for absolute and relative liver weight. Thus, the results of the present experiment demonstrate that short-term FW and refeeding influence underlying growth mechanisms of supply organs, such as hepatic and intestinal tissue, in addition to affecting overall growth and muscle development.

Analysis of Variance↗

PubMed1997

Nucleic acid concentrations and ornithine decarboxylase activity in tissues from three lines of turkeys.

Developmental patterns in turkeys of tissue ornithine decarboxylase (ODC) activity and nucleic acid concentrations were studied in a randombred control (RBC2), in a subline of RBC2 selected for increased 16-wk BW (F), and in a commercial sire line (C). Lines F and C were similar in BW, but Line C had greater breast weight than Line F. Lines F and C were heavier and had greater breast weights than the RBC2 population. Tissue ODC activity reached its highest level on Day 2 posthatch, declined rapidly through 13 d of age, and remained relatively low through 144 d of age. The ODC activity of liver tissue was greater than that of either breast or leg muscle. Line C had greater tissue ODC activity at 2 and 8 d of age than the RBC2 population, but Line F was not different from C or RBC2. There were no line differences for ODC activity at the other ages tested, resulting in a age by line interaction. The DNA content of muscle tissue was greatest at hatch and declined to baseline values by 55 d of age. The DNA content of breast muscle was higher than for leg muscle at hatch, but this pattern was reversed following Day 8. Muscle tissue from Lines F and C had a lower DNA content than that of the RBC2 population. Although the RNA content of muscle tissue was similar across lines, the RNA content of breast muscle was greater than for leg muscle during the early posthatch period just prior to the onset of rapid growth in this tissue. Results of the present experiment demonstrate changes in muscle functional cellularity during the growth phase in association with genetic increases in BW, but not breast muscle development. In contrast, tissue ODC activity was increased in association with genetic increases in breast muscle development, but not BW.

Aging↗

PubMed1997

Effect of the genetic selection of turkeys for increased body weight and egg production on immune and physiological responses.

Selection of poultry for fast growth rate is often accompanied by a reduction in specific immune responses or increased disease susceptibility. In this study, 17-wk-old male turkeys from each of four closed genetic lines, a randombred control (RBC) line and its subline (F) selected for increased 16-wk BW, and another RBC and its subline (E) selected for increased egg production, were tested for in vivo response to toe web inoculation with phytohemagglutinin-P (PHA-P), in vitro response of lymphocytes in whole blood to PHA-P and concanavalin A (Con A), hemolytic complement activity, differential white blood cell counts, hematology, and serum chemistry values. Fifteen male turkeys from each of two commercial lines, Com A and Com B, were also tested. The large-bodied F line birds had a lower toe web response to PHA-P, lower lymphocyte counts, and lower relative spleen weights than their smaller parent line. Body weights, total erythrocyte counts, blood urea nitrogen (BUN) levels, and in vitro mitogenic response to PHA-P and Con A were higher in the F line birds. Line E had lower hemolytic complement levels, lower relative spleen and relative bursal weights, and a higher in vitro mitogenic response to PHA-P than its parent line. The Com B line had a lower toe web response to PHA-P, and lower serum levels of gamma-glutamyltransferase and bilirubin than Com A. Line Com B had higher total RBC counts and higher levels of alanine aminotransferase (ALT) than Com A. These results support the concept that some changes in the cell-mediated immune response, as well as other physiological changes that may potentially affect immune response, appear to accompany selection for faster growth.

Alanine Transaminase↗

PubMed1997

Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 12. Heterosis in reciprocal crosses between divergently selected lines.

A selection experiment was started using Japanese quail to study the genetics of BW and plasma yolk precursor (measured by total plasma phosphorus; TPP). Lines were divergently selected for 4-wk BW (HW and LW) or plasma TPP (HP and LP). Sublines of HW were developed by continuing to select the males for increased 4-wk BW while selecting the females for increased (HW-HP line) or decreased (HW-LP line) TPP. The purpose of the present study was to determine the inheritance of traits associated with growth and reproduction in reciprocal crosses between the divergently selected lines and sublines. Reciprocal crosses were made between the HW and LW, HP and LP, and HW-HP and HW-LP lines. Traits measured included BW at various ages, age at sexual maturity, egg production, ovarian follicular development, egg weight, TPP, wet and dry liver weights, and occurrence of smooth muscle tumors in the ligaments of the oviduct. The HW line differed from the LW line in all traits measured except TPP and weight of smooth muscle tumors. No offspring were obtained from the HW x LW matings (male listed first). In the LW x HW cross, heterosis was negative for BW through sexual maturity and age at sexual maturity. Positive heterosis was observed for egg production, egg weight, and occurrence of smooth muscle tumors. Differences between the HP and LP lines were observed in the selected trait (TPP) and some correlated traits (BW at some ages, age at sexual maturity in females, egg production, and number and total weight of ovarian follicles). Positive heterosis in the HP and LP crosses was observed for BW, egg production, egg weight, and number of ovarian follicles whereas negative heterosis was observed for TPP and age at sexual maturity in females. The HW-HP and HW-LP lines differed in the selected traits and some correlated traits (egg weight and weights of the liver and smooth muscle tumors). Positive heterosis in the crosses was observed for BW, egg production, and liver weights whereas negative heterosis was evident for age at sexual maturity and TPP.

Animals↗

PubMed1997

Dietary interactions between lysine and threonine in broilers.

Two experiments were conducted to evaluate the effects of two dietary levels of lysine and four dietary levels of threonine in a factorial arrangement on broiler growth, carcass traits, and immunity. In both experiments, 120 broilers were allocated to each of 56 floor pens (6,720 total broilers). In Experiment 1, two levels of lysine (1.10 and 1.20% of diet) and four levels of threonine (0.68, 0.74, 0.80, and 0.86% of diet) were fed to broilers from 1 to 18 d of age in a sorghum-peanut meal diet. Body weight gain, feed:gain, mortality, and cellular and humoral immunity were measured. In Experiment 2, all broilers received a common basal diet up to 18 d of age. Experimental diets were fed from 18 to 34, 34 to 44, and 44 to 54 d of age. Two levels of lysine [100 and 105% of NRC (1994) recommendations] and four levels of threonine [83, 92, 100, and 108% of NRC (1994) recommendations] were included in the experimental diets for each age group (seven replications per treatment). The diets consisted of wheat (soft), corn gluten meal, soybean meal, and meat and bone meal Weight gain, feed:gain, mortality, and carcass traits were measured at 54 d of age. In Experiment 1, increasing dietary lysine from 1.10 to 1.20% from 1 to 18 d in broilers improved (P < 0.001) BW gain (453 vs 488 g) and feed:gain (1.39 vs 1.33). No interactions between lysine and threonine were observed in Experiment 1. Differences in immune parameters or mortality were not observed. In Experiment 2, an interaction in 18 to 54 d weight gain occurred with the highest gain in broilers receiving dietary lysine and threonine levels equivalent to 100 and 83%, respectively, of NRC (1994) or lysine and threonine at levels of 105% and 100% of NRC (1994), respectively (P < or = 0.05). Supplemental lysine (105% of the 1994 NRC) improved (P < or = 0.01) 18 to 54 d feed:gain (2.30 vs 2.26). No differences in mortality occurred. Supplemental lysine increased preslaughter weight (P < or = 0.05), but differences in carcass yield were not observed. Breast fillet yields were the highest (P < or = 0.03) in broilers receiving 100% of NRC lysine and 83 or 92% of NRC threonine or 105% of NRC lysine and 100 or 108% of NRC threonine. In conclusion, additional lysine improved feed:gain independent of threonine from 1 to 54 d of age. However, lysine and threonine interact to increase weight gain and breast fillet yields.

Aging↗

PubMed1996

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.

Animals↗

PubMed1996

Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 10. Response to selection over thirty generations.

Japanese quail lines were divergently selected for 30 generations for 4-wk BW (HW, LW) or plasma yolk precursor (HP, LP) as measured by total plasma phosphorus (TPP) at the beginning of lay. The HW, LW, HP, and LP lines were initiated from a randombred control line (R1). In the ninth generation of selection in the HW line, sublines were developed by continuing to select males for increased 4-wk BW whereas females were selected for increased (HW-HP line) or decreased (HW-LP) TPP. Individual selection was used in the HW, LW, HW-HP, and HW-LP lines. In the HP and LP lines, females were individually selected whereas males were selected on their full-sisters' performance. Realized heritabilities (h2), based on the linear regression of selection responses (corrected for environmental changes) on accumulated selection differentials (weighted for the number of offspring produced) over generations, declined with selection in the HW, LW, HP, and LP lines. The h2 of 4-wk BW in the HW line was 0.42 during the first 10 generations of selection and then declined to 0.30 during the next 2 generations of selection. In the LW line, realized h2 of 4-wk BW was 0.40, 0.16, and -0.12 in Generations 1 through 10, 11 through 20, and 21 through 30, respectively. The respective h2 for TPP in the HP line were 0.29, 0.17, and 0.14. The h2 of TPP in the LP line was 0.35 during the first 10 generations and essentially zero during the next 20 generations. Four-week BW and TPP were negatively associated in the HW, HP, and LP lines. There was no significant relationship between these two traits in the LW line.

Animals↗

PubMed1996

Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 11. Correlated responses over thirty generations.

Japanese quail lines were divergently selected for 4-wk BW (HW and LW lines) and plasma yolk precursor [total plasma phosphorus (TPP); HP and LP lines] for 30 generations. The base population was a randombred control line (R1) that was maintained along with the selected lines. Sublines were established from the ninth selected generation of HW by continuing to select males for increased 4-wk BW and selecting females for increased (HW-HP line) or decreased (HW-LP line) TPP. Correlated responses over the entire selection period were measured. Egg production of HW, LW, HP, and HW-HP declined over generations. There was positive quadratic component to the change in HW indicating that the change in egg production over generations was decreasing. There was no significant change in egg production of LP. Number of ovarian follicles in rapid development increased in LP and decreased in LW and HP. Total follicular weight increased in HW and LP and decreased in LW. Production of abnormal eggs increased over generations in HW and HW-HP. Body weight at the beginning and end of the laying period increased in HW, HW-HP, HW-LP, and LP and decreased in LW. Egg weight increased in HW HW-HP and decreased in LW and LP. The increase in egg weight of HW was due to a disproportionate increase in shell and yolk. Wet weight of the liver increased in HW and decreased in LW and HP. Dry liver weight decreased in LW, HP, and LP. Mortality to 4 wk of age increased in LW, HP, and LP.

Animals↗

PubMed1996

Short-term selection for four-week body weight in Japanese quail.

Japanese quail have been utilized as a research animal to establish genetic relationships that may be present in other poultry species. In this presentation, short-term selection experiments were reviewed. Selection intensity appeared to be the most effective in improving BW when selection experiments were compared on a response per generation basis; however, when generation interval was reduced, the response per year was superior despite lower selection intensities for lines selected the same number of generations. Correlated responses over 30 generations of divergent selection for 4-wk BW indicated that selection had a negative effect on fitness traits, including egg number and fertility. Traits such as follicle and egg weight and BW at the beginning of and after a 120-d laying period were positively correlated with BW during the growth period. The early response of quail lines selected for increased BW at 10, 17, 28, and 40 d of age indicate that the later selection is applied the greater the selection response at maturity. In fact, lines selected at young ages were competitive with late-selected lines only to the point at which selection occurred.

Aging↗

PubMed1995

Inheritance of carcass variables when giant jungle fowl and broilers achieve a common physiological body weight.

Ten chicks each from Giant Jungle Fowl (JF), broiler breeders (BB), and the respective F1 cross between them, were reared under typical broiler management practices until they reached a market weight of approximately 1,818 g. When individual birds reached market weight they were killed by CO2 asphyxiation and variables (length and weight) associated with organ, muscle, and skeletal growth were measured. Age to market weight demonstrated parental and heterotic effects. The JF had more deboned leg muscle and less Pectoralis major muscle than BB. Abdominal fat was higher in BB and showed positive heterosis. Organ weights were consistently lower for JF than BB. Positive heterosis was observed for spleen and pancreas, and negative heterosis was indicated for heart, liver, and lung. The digestive tract generally weighed less and was shorter in length for JF than for BB. Positive heterosis was observed for proventriculus and gizzard weight, and negative heterosis was noted for duodenum and jejunum lengths. Parental line differences were observed for most bone variables, including weight and length. Parental lines differed for femur breaking strength, but not for tibiotarsus breaking strength. A large negative heterotic effect was observed for tibiotarsus bone breaking strength.

Age Factors↗

PubMed1995

Evaluation of a noninvasive technique for measuring fat-free mass in poultry.

Total body electrical conductivity (TOBEC) has been successfully used to predict fat-free mass and lipid content in various species of mammals and birds. In the current trial, TOBEC was used to predict fat-free mass in broiler chicks through 14d posthatch. To accomplish this, a calibration equation was developed and then tested for accuracy of prediction. It was determined that two calibration equations (hatch to 4 d and 6 to 14 d) were necessary to predict growth. Equations including only the TOBEC reading had R2 values of .92 (6 to 14 d) and .96 (hatch to 4 d). Equations including additional measures of length or weight had slightly improved R2 values. Through the verification of the calibration equations it was found that when the equations were used in the appropriate range, 95% of the variation in fat-free mass was explained. It was determined that TOBEC measures can be used to predict fat-free mass in live broiler chicks to 2 wk posthatch.

Adipose Tissue↗

PubMed1995

The influence of genetic changes in body weight, egg production, and body conformation on organ growth of turkeys.

Measurements were made on the breast with bone (BWB), a demand organ, and various supply organs in mature turkeys (approximately 40 wk of age) from various lines of turkeys to determine the influence of selection for increased egg production, BW, and body conformation on resource allocation. Comparisons made were: 1) a line (E) selected long-term for increased egg production and its randombred control (RBC1); 2) a line (F) selected long-term for increased 16-wk BW and its control (RBC2); 3) the F line with a commercial sire line (C); and 4) the RBC1 line and a randombred control (RBC3) that was formed from the F and C lines. Data were analyzed on an absolute basis and after adjustment to a common BW by covariance analysis. The only major change in organ sizes that occurred that could not be accounted for by differences in BW was in the E line. The actual and relative weights of total supply organs decreased and the relative weight of the BWB increased in the E line when compared with its randombred control. Selection for increased BW in the F line did not result in a relative change in BWB. The BWB weight was relatively heavier in the C line than in the F line. The relative amount of BWB was slightly but significantly different in the two randombreds (RBC1 and RBC3) formed 29 yr apart. Weight of the gizzard did not increase at the same rate as BW in two large-bodied lines (F and RBC3).

Animals↗

PubMed1995

Liver and blood glutathione in male broiler chickens, turkeys, and quail.

The objective of the present study was to establish age relationships for hepatic and whole blood glutathione (GSH) in male broiler chickens, quail, and turkeys utilizing lines within each poultry species with different rates of growth. Liver and blood samples were obtained from three quail lines (light, medium, and heavy) at 3 and 6 wk of age, from two turkey lines (light and heavy) at 10 and 20 wk of age, and two broiler lines (medium and heavy) at 3, 5, and 7 wk of age. With the exception of the heavy turkey line, older birds generally exhibited higher hepatic GSH concentrations than younger birds. There was no apparent age-related difference in whole blood GSH, nor was whole blood GSH correlated with hepatic GSH in any poultry species.

Age Factors↗

PubMed1994

Evaluation of the humoral immune response to different antigens in Arkansas Regressor and Progressor chickens.

Arkansas Regressor and Progressor chickens were re-evaluated for their immune response to different antigens. Chickens received i.v. injection of either SRBC (10 birds per line) or Salmonella pullorum (SP; 10 birds per line) at 7 wk of age, and sera were collected at 6, 13, and 20 d postimmunization. A third group of birds (10 birds per line) received and i.m. injection of GAT emulsion at 7 and 12 wk of age, and sera were collected at 10 and 14 wk of age. There were significant differences between the two lines in their humoral immunity to SRBC, SP, and GAT. Such results suggest genetic control of humoral immunity to these antigens in these lines. It is unknown whether humoral immunity to these antigens is correlated to regression of tumors induced by Rous sarcoma virus.

Animals↗