Enhancing the immunity and egg production of stressed laying birds by supplementing organic chromium

Abstract

An experiment was conducted to improve the immunity and egg production of stressed laying birds by organic chromium supplementation for a period of 6 weeks. Total of 5000 birds (White Leghorn chicken, BV 300 strain) were divided into 5 groups (T1 to T5) having 10 replicates in each group and each replicates having 100 birds with an initial age of 33 weeks. The experimental groups are as follows: T1 is control unaffected by Newcastle disease (ND); all other groups (T2 to T5) were affected by ND and recovering from the disease. T2 is not supplemented with chromium source and act as negative control. T3, T4 and T5 were supplemented with chromium chloride, chromium yeast and chromium picolinate @ 300 ppb, respectively. The results revealed that weekly average egg production was significantly (P<0.01) high in T1 followed by T4 during first week of supplementation and increased further. The egg production recovery was very faster in T4. However, T5 groups showed significantly less egg production throughout the experiment except 6th week. The feed intake was similar in all groups except control group. The mean HI titre for NDV was significantly (P<0.01) higher in T4 followed by T5 and least in T2 and T3 during first week of vaccination. The titre was reached at the level of unaffected highly immune bird by second week in T4. However it was reached by other group on sixth week after immunization except T5. Organic chromium supplementation (T4 and T5) reduced the mortality significantly (P<0.01) in laying birds. The reduction in the mortality compare to untreated T2 is about 62.6 % in T4 and 59.0 % in T5. The beneficial effect of chromium on egg production can be related to its stress relieving effect, since the treatments were given at the time of low egg production after recovery from Newcastle disease. As a result increase in egg production in ND affected birds and increase in HI titre by means of inclusion of organic chromium to layer feeds could be useful feeding strategies. The return on investment was calculated and was high in chromium yeast (8.28) than the chromium picolinate (5.43) during stress condition. The improvement in egg production and return on investment on supplementation of chromium ensures economical benefit to the farmer.