RESUMEN
The 300 day old Kadaknath chicks were randomly distributed into five treatment groups A, B, C, D and E with three replicates having 20 birds in each and reared up to 6th weeks. The treatment groups were viz., control group A: birds fed diet CP 18%, ME 2700 kcal/kg, Methionine 0.38%, Lysine 0.85%; B: diet CP 19%, ME 2800 kcal/kg, Methionine 0.40%, Lysine 0.90%; C: diet CP 20%, ME 2900 kcal/kg, Methionine 0.48%, Lysine 1.00%; D: diet CP 21%, ME- 3000 kcal/kg, Methionine 0.45%, Lysine 1.10%; E: diet CP 22%, ME 3100 kcal/kg, Methionine 0.50%, Lysine 1.20 %. The body weights and weight gain in group D were significantly (P<0.01) higher than other treatment groups except group B at 6th week. The significantly lower feed intake was observed in group D compared to control group at 1st and 3rd weeks. The feed conversion ratio was significantly (P<0.01) better in groups B (3.74±0.06), D (3.70±0.10) and E (4.18 ±0.13) compared to control group (4.70±0.25). The antibody titres against Ranikhet disease were non-significant in all treatments at 3rd and 6th weeks. The cost of production in rupees per kg live weight was recorded lowest in group D (217.56) followed by groups B (218.62), C (255.39), E (256.23) and A (261.11). It may be concluded that the rearing of Kadaknath chickens under intensive system fed starter diet containing ME 3000 kcal/kg, CP 21%, Lysine 1.10% and Methionine 0.45% recorded best growth performance, better immune response and lowest cost of production at the end of 6th week
RESUMEN
In this study, susceptibility to H5N1 virus infection was studied in two Indian native chicken breeds viz. Kadaknath and Aseel (Peela) and an Indian synthetic broiler strain (Synthetic dam line (SDL-IC). Fifty birds from each genetic group were infected intra-nasally with 1000 EID50 of a highly pathogenic avian influenza virus (HPAIV) strain A/chicken/Navapur/India/7972/ 06 (H5N1) and observed for a period of 10 days. Significant differences in severity of clinical signs, gross lesions and time for onset of symptoms were observed. The overall severity of clinical signs and gross lesions was less in SDL-IC broilers as compared to the other two genetic groups. The mortality percentages were 100, 98 and 92% with Mean Death Time (MDT) of 3.12, 5.92 and 6.96 days, respectively for the two native breeds Kadaknath and Aseel (Peela), the and SDL-IC broiler strain. Comparison of histological lesions revealed differences in disease progression among the genetic groups. Vascular lesions such as disseminated intravascular coagulopathy (DIC) were predominant on 3 days post infection (dpi) in Kadaknath, and on 5 and 6 dpi in Aseel (Peela) and SDL-IC broiler. The mean log2 HA titres of the re-isolated virus from various organs of H5N1 AIV infected birds of the three genetic groups ranged from 2.32 (lung, trachea and bursa) to 5.04 (spleen) in Kadaknath; 2.32 (lung) to 6.68 (brain) in Aseel (Peela); and 2.06 (liver) to 7.01 (lungs and kidney) in SDL-IC broiler. These results suggest that the susceptibility to H5N1 highly pathogenic avian influenza virus infection differed among the three breeds; Kadaknath being highest followed by Aseel (Peela) and synthetic SDL-IC broiler.This is possibly the first report on the differences in the susceptibility of the India native breeds to H5N1 virus infection and its severity.