Use of avian immunoglobulins in the control of coccidiosis
Morales1, GA., García1, LD., Rodríguez1, RA., Lucio1 DE.
1 Investigación Aplicada S.A. de C.V.
Tehuacán Puebla, México
Coccidiosis research should be
directed towards the control of the parasites through immunological methods,
including the generation of new vaccines or other methods with special emphasis
in avoiding detrimental lesions, in diminishing time to develop an effective
immune response as well as in avoiding the drug-resistance problem derived from
chemotherapy. Transfer of humoral immunity from hyperimmunized hens to
susceptible chicken may be an attractive alternative. The aim of the present
research was to demonstrate the usefulness of avian immunoglobulins in the
control of coccidiosis.
MATERIAL AND METHODS: Two ml of specific liquid immunoglobulins against Eimeria
spp. obtained from egg yolks of hyperimmunized SPF hens were administered by
oral route to thirty chickens (2 groups of 15 each). A second group of thirty
birds received the immunoglobulins in a dry form at a dose of 100g/T of feed,
and a control group of thirty birds received food without any anticoccidial drug
plus placebo. The treatments were administered during two weeks before challenge
with 150,000 oocysts of E acervulina and E maxima by oral route. The treatments
continued for one more week and the birds were sacrificed and submitted to
necropsy. Weight gain , feed conversion, oocyst count in the gut, and lesion
scores were determined. Birds were housed under controlled conditions along the
whole assay.
RESULTS: The weight gain during the last week was of 273 and 220 g for the group
which received immunoglobulins in the feed, whereas the group of liquid
immunoglobulins had 281 and 310 g and the control group 193 g . Feed conversion
was of 1.82 and 1.85 for the birds that received liquid treatment as compared
with 1.66 and 1.74 in the feed plus immunoglobulins group. The control group
showed feed conversion of 1.98. The average lesion score was 1.67 and 1.87 in
the liquid treatment group, 2.06 and 2.13 in the feed plus immunoglobulin group
and 2.8 in the control group. In both treated groups, a 126,000 oocyst count was
recorded as compared to 192,000 oocysts in the control group.
DISCUSSION The liquid treatment group showed the best performance in weight gain
as compared to feed plus immunoglobulin and control groups. Lesion scores of the
liquid treatment and the feed plus immunoglobulin groups were lower as compared
with the control group. A significant reduction (66%) in oocyst production was
observed in the treated groups as compared to the control group. The specific
antibodies against coccidia provided effective protection decreasing intestinal
damage and oocyst production. Antibody therapy may be an innocuous tool in the
control of coccidiosis in birds.