N. S. Singh

Studies on immunocompetence status in two turkey varieties in India

1. Two hundred and twenty-seven adult turkeys of both sexes, of two varieties (104 Black and 123 White) were used to evaluate their immunocompetence status and body weights. 2. Response to sheep red blood cells (SRBC) (humoral immunity) was measured by Haemagglutination (HA) test 5 days post immunisation (dpi) and expressed as log2 values. Mercaptoethanol resistant (MER) antibodies representing IgG were determined by Mercaptoethanol HA test and Mercaptoethanol sensitive (MES) antibodies, representing IgM as the difference in total HA titre and IgG. Serum lysozyme concentrations were estimated by ‘Lysoplate assay’ and expressed in log2 values. 3. Least squares analysis of variance revealed that the White variety had higher adult body weight (4·788 ± 0·040 kg) than the Black (3·774 ± 0·044 kg). Sexual dimorphism was apparent and meals were heavier then females in both varieties. The interaction effect of variety and sex on body weight was also significant. 4. Least squares means for immunological traits, namely, total anti-SRBC antibodies, MER, MES titres and serum lysozyme were 7·161 ± 0·189, 0·801 ± 0·071, 6·362 ± 0·160 and 1·766 ± 0·043 µg/ml, respectively. The Black variety had a higher MES antibody titre than the White. 5. Sex had an effect on all the immunological traits except on MER titres. Females generally had higher anti-SRBC, MER and MES titres and serum lysozyme. The variety × sex interaction effect was significant for MES titres and serum lysozyme. White males had the lowest MES titres.

Influence of Selection for High Humoral Immunity on Selected and Unselected Traits in Black Variety of Turkey

Abstract Singh, N.S. and Kumar, S. 2007. Influence of selection for high humoral immunity on selected and unselected traits in black variety of turkey. J. Appl. Anim. Res., 32: 139–143. Direct and correlated changes were evaluated in the immunological traits (total, mercaptoethanol resistant (MER) and sensitive (MES) antibodies, serum lysozyme level and PHA-P response and body weights (0 to 24 weeks) in S1generation of Black turkey variety, selected for higher immune response to sheep RBCs (SRBC). The selected line had comparatively higher (P>0.05) LS means for all immunological traits except for serum lysozyme level. Hatch effect was significant on MER antibody titre and serum lysozyme level only. Females had significantly higher titre? of HA and MES (P<0.1) and lower response to PHA-P (P<0.05). Control line had comparatively higher body weights at 20 and 24 weeks of age. Realized h2 estimate as a response to selection was 0.499 indicating the effectiveness of selection.

Genetic Studies of Growth Traits in White Turkey Line Selected for High Humoral Immune Response

Abstract Singh, N.S., Kumar, S. and Majumdar, S. 2003. Genetic studies of growth traits in White Turkey line selected for high humoral immune response. J. Appl. Anim. Res., 24: 193–200. The growth performance of 138 poults obtained in 2 hatches belonging to White variety of turkey, undergoing selection for response to Sheep RBC was studied. Least squares means of body weights reached 1000 g by 10 weeks and 2000 g by 16 weeks of age. The body weights were affected significantly by hatch. The h2 estimates of body weights except at hatch and 16 weeks of age were high (0.612±0.497 to 0.792±0.587) exhibiting the presence of additive genetic variation. The phenotypic correlations (rp) among body weights at different ages were generally positive and high (P<0.05 or 0.01). Genetic correlations rG among body weights were positive but most of the estimates were more than unity. The rp had smaller magnitudes as compared to their corres-ponding rG. The findings suggested that 4 or 8 weeks body weights might be used as selection criterion for improvement of body weights at later ages.