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Biomedical subjects

Y M Saif

Publications and source records attributed to Y M Saif.

At least 37 records · Page 2Linked to original sources
PubMed1997

In-vitro antimicrobial susceptibility of Clostridium perfringens from commercial turkey and broiler chicken origin.

The minimum inhibitory concentrations (MIC) of eight antibiotics and two anticoccidial agents were determined for Clostridium perfringens strains isolated from 26 commercial broiler farms and 22 commercial turkey farms. Isolates were obtained from the intestines of birds on the farm or as the processing plant using standard culture and identification techniques. The microbroth dilution test was used to determine the MIC for each compound. Most isolates from chickens had MICs in the range of 2-16 mg/L for tilmicosin, tylosin and virginiamycin, whereas the MICs for avilamycin, avoparcin, monensin, narasin and penicillin were < or = 1 mg/L. Most strains from chickens had high MICs (> or = 64 mg/L) and appeared to be resistant to bacitracin and lincomycin. Most turkey isolates had MICs in the range of 2-16 mg/L for bacitracin, tilmicosin, tylosin and virginiamycin, with strains exhibiting MICs < or = 1 mg/L for avilamycin, avoparcin, monensin, narasin and penicillin. Several turkey isolates had MICs > or = 64 mg/L to lincomycin. No attempt was made to associate farm usage of a particular antibiotic to the antibiograms.

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PubMed1996

The influence of major histocompatibility complex genotypes on resistance to Pasteurella multocida and Newcastle disease virus in turkeys.

Sublines homozygous for each of four MHC haplotypes were developed from randombred control populations of turkeys and challenged with Pasteurella multocida (capsular serogroup a, somatic serotype 3, 4) at 6 wk of age or Newcastle disease virus (NDV; Texas GB strain) at 4 wk of age. In addition, individuals from a randombred control line (RBC2) and a subline (F) of RBC2 long-term selected for increased 16-wk BW were included in most of the challenge trials. The duration of the challenge trials was 2 wk for both organisms. Mortality following challenge with P. multocida or NDV was higher in the F line than in its randombred control. The MHC genotypes differed in mortality following exposure to both organisms but the rankings of the genotypes were not the same for P. multocida and NDV. The increased susceptibility of the F line to both organisms could not be explained by known changes in the frequency of the MHC haplotypes.

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PubMed1996

Influence of growth selection in turkeys on resistance to Pasteurella multocida.

Four lines of turkeys, a randombred control (RBC2) started in 1966 and three sire lines (F, A, and B), were challenged with a field isolate of Pasteurella multocida (capsular serogroup A, somatic serotype 3, 4) at 6 wk of age. Line F, a subline of the RBC2 line, was selected for 28 generations for increased 16-wk BW and Lines A and B were primary breeding sire lines from two commercial breeders. Each bird was inoculated subcutaneously in the back of the neck with 1.2 x 10(7) washed bacteria. Mortality following challenge with P. multocida was higher in the sire lines (54 to 65%) than in the RBC2 line (26%). There was no significant difference in mortality among sire lines following challenge. These results suggest that the increased susceptibility to P. multocida in the F line in comparison to its control may be due to genetic changes resulting from selection for increased BW in this line.

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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).

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PubMed1994

Genetic analysis of antibody responses of turkeys to Newcastle disease virus and Pasteurella multocida vaccines.

Heritability (h2) of 16-wk BW and primary and secondary antibody responses and genetic and phenotypic correlations among these traits were estimated for 931 male and female turkeys vaccinated with Newcastle disease virus (NDV) and Pasteurella multocida. Turkeys from a line selected for 22 or 23 generations for increased 16-wk BW were vaccinated at 6 and 12 wk of age with blood samples collected 3 wk postvaccination. Antibody titers were determined using an ELISA method and transformed to log(e) for analysis. Heritability estimates for primary and secondary antibody responses to NDV were .380 +/- .070 (SE) and .296 +/- .063, respectively. For primary and secondary antibody responses to P. multocida, h2 estimates were .458 +/- .075 and .333 +/- .066, respectively. Heritability estimate for 16-wk BW was .404 +/- .071. The genetic correlation between primary and secondary antibody responses to NDV was .491 +/- .150. There was no genetic correlation between primary and secondary antibody responses to P. multocida. Although the genetic correlation between primary antibody responses to NDV and P. multocida was .292 +/- .159, the genetic correlation between secondary responses to the two antigens did not differ from zero. There were no genetic correlations between antibody responses and 16-wk BW. Similar results were observed for phenotypic correlations. Based on heritability and genetic correlation estimates, it would be possible to improve antibody responses to either NDV or P. multocida singularly; however, to improve antibody responses to both antigens, selection would have to be applied for each antigen.

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PubMed1991

Immunosuppression induced by infectious bursal disease virus.

Immunosuppression caused by infectious bursal disease virus (IBDV) is of major interest because of the widespread occurrence of the infection in commercial chickens. Infection with IBDV at an early age significantly compromises the humoral and local immune responses of chickens. The cellular immune response is also compromised by apparently to a lesser extent and for a short period. The immunosuppression seems to be a result of direct effect (lysis) of B cells or their precursors. Other mechanisms of immunosuppression have been suggested, notably the development of suppressor cells.

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PubMed1991

Genetic association of selection for increased leg muscle and increased shank diameter with body composition and walking ability.

Body compositions of a randombred control population (RBC2), a line selected for increased 16-wk BW (F), a line selected for increased shank diameter (FL), and a line selected for increased leg muscle mass (FM) were compared at 16 wk of age. The F line originated from the RBC2 population and the FL and FM lines were developed as sublines of the F line. The F and FL lines were developed through mass selection of BW and shank width, respectively. The FM line was developed through family selection for leg muscle mass. Selection for BW in the F line has resulted in an increase in the proportion of breast muscle and a decrease in the relative amount of leg bone in comparison with the RBC2 population. Selection for increased shank width in the FL line has increased not only shank weight but has produced concomitant increases in the weight of the tibiotarsal and femur bones. Although FL line has also shown a correlated increase in BW in association with increases in shank width the increase in leg bone weight was relatively greater than the increase in BW. Therefore, the relative weights of leg bones in the FL line increased such that they were more similar to the RBC2 population than to the F line. Although the amount of leg muscle increased slightly in the FM line, the relative proportion of leg muscle did not increase significantly. The selection program used was probably ineffective in increasing the proportion of leg muscle because of the high percentage (low selection intensity) of families selected and small family size for estimating family means.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1989

Effect of hatching egg sanitizers on embryonic survival and hatchability of turkey eggs from different lines and on egg shell bacterial populations.

Three experiments were conducted to examine the effect of hatching egg sanitizers on embryonic survival, hatchability, and microbiological populations of turkey eggs. Each experiment consisted of two trials. Experiments 1 and 2 were designed to examine embryonic survival and hatchability following sanitization. Experiment 3 examined postsanitization levels of bacteria on the shell surface and inside the egg at Day 7 of incubation. In Experiment 1, formaldehyde fumigation (FF) was compared to quaternary ammonium (QA). In Trial 1, eggs of 359 hens representing 10 lines were randomly assigned to one of the two treatments. In Trial 2, 3,890 eggs produced from a cross of randombred control line (RBC2) females with commercial sire line (C) males were randomly assigned to one of the two treatments. Differences due to sanitizing treatment were nonsignificant in both trials. Line was significant for 7-day embryonic survival and hatch of surviving embryos in Trial 1. In Experiment 2, QA was compared with QA plus U.S.P. Formalin (QAF). In Trial 1, eggs of 288 hens representing 10 lines were randomly assigned to one of the two treatments. In Trial 2, 1,058 eggs produced from the cross of RBC2 females with C males were randomly assigned to one of the two treatments. Differences due to sanitizing treatment were significant only for 7-day embryonic survival in Trial 2; embryonic survival was highest for QA. Line differences in Trial 1 were significant (P less than .01) for 7-day embryonic survival and hatch of surviving embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1989

Influence of selection for increased body weight on the incidence of leiomyomas and leiomyosarcomas in Japanese quail.

Leiomyomas and leiomyosarcomas were observed in adult laying hens from lines of Japanese quail selected solely (HW) or partly (HW-HP; HW-LP) for increased 4-wk BW and the corresponding randombred control (R1). No neoplasms were observed in a line (LW) selected for decreased 4-wk BW based on observations in one generation. Line R1 served as the base population for Lines HW and LW and was maintained without conscious selection for any trait, Lines HW-HP and HW-LP were sublines of Line HW in which the males were selected for increased 4-wk BW and the females were selected for high or low levels of plasma total phosphorus, respectively. Hens of all lines were necropsied after completing a 120-day production period. A high incidence of neoplasms were found in the dorsal and ventral ligaments of the oviduct in the immediate vicinity of the magnum, and the incidence was much greater in the lines selected for increased growth than in Line R1. These results suggest that selection for increased BW in Lines HW, HW-HP, and HW-LP has resulted in genetic changes that are conducive to neoplastic growth. Based on the results of one generation, it appears that selection for decreased 4-wk BW reduced incidence of neoplasms.

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PubMed1988

Antibody response to Newcastle disease virus and Pasteurella multocida of two strains of turkeys.

The primary and secondary response to Newcastle disease virus (NCDV) and Pasteurella multocida (PM) of two turkey lines were studied following vaccinations with either NCDV or PM alone, or in combination. The two turkey strains were 1) a randombred control line (RBC1) and 2) a subline (E) of Line RBC1 selected 27 generations for increased egg production. This study consisted of five trials. Each trial represented a separate hatch. In Trial 1, poults of each line were subcutaneously vaccinated with a 1-mL dilution of B1 type LaSota strain NCDV vaccine. In Trial 2, poults of each line were wing-web vaccinated with the M-9 strain of PM Heddleston Type 3 x 4 cross at 6 and 10 wk of age. In Trial 3, poults of each line were subcutaneously vaccinated on the back of the neck with 1 mL of inactivated NCDV at 6 and 10 wk of age. In Trial 4, .5 mL of a PM bacterin containing Types 1, 3, and 4 in an oil emulsion was used to subcutaneously vaccinate poults of each line at 6 and 10 wk of age. In Trial 5, poults of each line were simultaneously vaccinated with inactivated NCDV (subcutaneously) and a PM bacterin (intramuscularly) at 6 and 10 wk of age. Line RBC1 had significantly (P less than .01) higher maternal antibodies to Newcastle disease at 3 wk of age than those of Line E. The RBC1 line generally had significantly higher levels of antibodies than Line E in response to vaccination for both NCDV and PM when administered singularly or in combination.

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PubMed1988

Response of two lines of turkeys to challenge with Pasteurella multocida.

Two lines of turkeys were challenged with Pasteurella multocida during three trials. The two lines were 1) a randombred control line (RBC1), and 2) a subline (E) of Line RBC1 selected for increased egg production. Each trial differed as to the age at which poults were challenged. In Trial 1, unvaccinated birds were subcutaneously inoculated with P. multocida at 6 wk of age. In Trial 2, poults vaccinated (on the back of the neck) at 7 and 9 wk of age with .5 mL of P. multocida bacterin and unvaccinated poults were challenged at 11 wk of age. Trial 3 was similar to Trial 2, except that poults were vaccinated at 8 and 10 wk of age and challenged at 12 wk of age. Line E had significantly (P less than .05) higher mortality than Line RBC1 (66.7 vs. 31.8%) in Trial 1. In Trials 2 and 3, unvaccinated birds of Line E had higher mortality than unvaccinated birds of Line RBC1; however, differences between lines were not significant in either trial. Significantly lower levels of mortality were observed for vaccinated poults than for unvaccinated poults in the second and third trials, where birds were vaccinated and challenged at older ages.

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PubMed1987

Age-related infections with rotavirus, rotaviruslike virus, and atypical rotavirus in turkey flocks.

The genome electropherotyping technique was used in longitudinal surveys to detect group A rotavirus, rotaviruslike virus (RVLV), atypical rotavirus (ATR), and reovirus in intestinal contents or fecal specimens collected from turkeys in 10 commercial and 2 research station flocks. These viruses were detected in turkeys from 8 to 10 commercial flocks surveyed. Of 278 specimens collected from turkeys less then 29 days old in commercial flocks, 79 (28.4%) contained one or more viruses, whereas only 1 of 120 specimens collected from turkeys older than 28 days had virus. Viruses were detected in commercial turkeys between 3 and 35 days old, and over a third of the specimens collected from birds during their first week of life were positive for group A rotavirus. Between 8 and 28 days of age, commercial turkeys were infected with group A rotavirus, RVLV, ATR, and reovirus. ATR was the only virus detected in birds older than 28 days. Overall, group A rotavirus and RVLV were each detected in 39 specimens, and ATR was detected in 7 specimens; reovirus was detected in 2 specimens. Eight of the positive specimens contained two viruses. All 102 specimens collected from turkeys 1 to 56 days old in the two research station flocks were negative for virus.

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PubMed1987

Comparison of bone and muscle growth in turkey lines selected for increased body weight and increased shank width.

A subline (FL) of a long-term growth-selected line (F) of turkeys was established by mass selecting solely for increased shank width at the narrowest point (dew claw). A comparison was made of bone and muscle growth in Line FL (fourth generation of selection), Line F (17th generation of selection), and a randombred control (RBC2, the base population of F) at 8, 16, and 20 wk of age. Also, a sample of the tibiotarsal and femur bones was studied histologically for evidence of pathological conditions. No significant pathological changes were observed in bones from turkeys of the different lines at the ages examined. Samples for histological study were taken at Day 1, 27, 56, 84, 112, and 140 posthatching. Genetic increases in body weight (F and FL lines) resulted in a significant decline in the relative amount of leg muscles from 16 to 20 wk of age while in Line RBC2 the relative amount of leg muscles increased slightly from 16 to 20 wk of age. This resulted in a significant line x age interaction. No significant differences in the amount of leg muscles were detected between turkeys of Lines F and FL. Amount of breast muscles increased consistently with age in all lines. Amount of breast muscles (absolute and as a percentage of body weight) was larger in Line F than in the FL and RBC2 lines. The actual weight of the breast muscles was larger in Line FL than in the RBC2 line but as a percentage of body weight there was no significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1986

Comparison of immune electron microscopy and genome electropherotyping techniques for detection of turkey rotaviruses and rotaviruslike viruses in intestinal contents.

Seventy-nine intestinal contents specimens from 65 turkey flocks were examined for rotavirus and rotaviruslike virus (RVLV) by immune electron microscopy (IEM) and genome electropherotyping. The IEM procedure was slightly more sensitive in detecting these viruses; 7 of 48 specimens (14.6%) positive for virus by IEM were negative by the genome electropherotyping technique. The genome electropherotyping technique more readily differentiated the rotaviruses and RVLVs than did the IEM procedure; 15 of 48 specimens (31%) positive for virus by IEM could not be differentiated into rotavirus of RVLV, whereas only 4 of the 41 specimens (9.7%) positive by genome electropherotyping produced incomplete genome electropherotypes and could not be differentiated. Thirty-one specimens negative by IEM were also negative by genome electropherotyping. Specimens determined to contain only rotavirus by IEM produced only rotavirus genome electropherotypes. Likewise, specimens determined to contain RVLV alone by IEM produced only RVLV genome electropherotypes. Three specimens contained viruses morphologically resembling rotaviruses that were not aggregated by either the anti-turkey rotavirus serum or the anti-turkey RVLV serum and possessed genome electropherotypes distinct from those of the turkey rotavirus and RVLV. These rotaviruses may represent a third, previously unrecognized serogroup of turkey rotaviruses.

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PubMed1985

The influence of genetic increases in shank width on body weight, walking ability, and reproduction of turkeys.

Body weight and breast width have been greatly increased in the modern turkey. However, the relative amounts of leg muscles and leg bones have declined. A similar decline also occurs with age. It was theorized that this is an inherent weakness that magnifies other causes of leg problems. In an attempt to increase the relative amount of leg bone, a subline (FL) was developed by mass selection for increased shank width at 16 weeks of age from a long-term growth-selected line of turkeys (F). Shank width of FL was increased greatly by selection. The realized heritability of shank width, based on the regression of accumulated selection response on accumulated selection differential, was .33 +/- .05 over five generations of selection. Body weight of males from FL increased at a rate comparable to that of F at 16 weeks of age. However, there was no comparable improvement in body weight of FL females, resulting in a significant line X sex interaction. A similar interaction was observed for body weight at 8 and 20 weeks of age in these lines. The genetic increases in shank width in FL resulted in significantly improved walking ability of males at 16 weeks of age in comparison to F, even though body weight of males from the two lines was similar. The walking ability of FL did not change relative to the control line from which F originated. Thus, large genetic increases in body weight of males can be achieved without loss in walking ability by genetic increases in shank width.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1978

Studies on metabolism and concentrations of immunoglobulin G in the newly hatched turkey poult.

Persistence of maternal IgG in the hatched turkey poult was studied using 125I-labeled egg yolk IgG injected at hatching. Determinations were made of the half-life of IgG in the total plasma pool, and results indicated half-life for IgG of 4.08 +/- 0.33 days. Elimination of the injected IgG (comparable with maternal IgG) was described as the percentage of the injected dose remaining in the plasma with 30.53%, 10.31%, and 3.48% of the injected dose at 7, 14, and 21 days, respectively, after injection.

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PubMed1978

Metabolism and passive transfer of immunoglobulins in the turkey hen.

Aspects of the metabolism and passive transfer of radioactive 125I-labeled IgG, IgM, and IgA from the turkey hen to the egg were studied. The half-life of 125I-labeled IgG in plasma was calculated to be 5.91 +/- 0.81 days, and the time of maximal passage of radioactivity from hen into eggs was 6.5 +/- 1.3 days. The following IgG determinations were made: plasma concentration (8.54 +/- 1.2 mg/ml), total plasma pool (0.518 +/- 0.07 g/kg), total turnover rate (0.062 +/- 0.01 g/kg/day), or 11.92 +/- 0.01% of the plasma pool per day. The overall passage of IgG into sequentially laid eggs of individual hens was at a constant rate over an observation period of 46 days; loss to egg yolks accounts for less than 1% of total daily irreversible loss of IgG from the hen's body. The IgG concentrations in egg yolks assayed in 3 hens ranged from 72.1 +/- 6.7 to 104.5 +/- 6.9 mg/yolk, with significant (P less than or equal to 0.01) differences observed between birds not accounted for by differences in egg weights. The IgG was detectable in egg whites, but at a low concentration. The biological importance of egg white IgG is questionable. In 2 hens examined, 125I-labeled IgM had a half-life of 2.69 and 2.74 days, with fractional turnovers of 25.76% and 25.29% of the plasma pool/day. The IgM-associated radioactivity in egg material was considered unimportant in overall immunoglobulin transfer into eggs. In 2 hens examined, 125I-labeled IgA (biliary) had a half-life of 1.92 and 1.68 days, with fractional turnovers of 36.09% and 41.25% of the plasma pool per day. Like IgM, IgA-associated radioactivity in egg material was considered unimportant in overall immunoglobulin passage into eggs.

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