We report the mitochondrial DNA (mtDNA) characterization of 77 indigenous chickens (fighting and meat birds) from Madagascar, using DNA sequences of the first hypervariable segment of the D-loop. Comparison with reference samples from the African continent and Asia revealed two mtDNA haplogroups, suggesting a dual geographic and genetic origin for the indigenous Malagasy chickens. The most common haplogroup was present in 65 individuals of the two types; it is likely of Indonesian origin. The second haplogroup was observed in 12 fighting birds and meat chickens; it could be of African continental origin and/or the result of recent introgression with commercial lines. We further studied a G/A single nucleotide polymorphism at nucleotide position 1892 bp of the coding sequence of the Mx gene that is reported to be one of the candidate susceptible/resistant genes to viral infection in chicken. Our results indicate the "susceptible" allele G is the most common with frequencies of 65% and 70% in Malagasy fighting and meat chickens, respectively. However, the allelic frequency difference between the two types of chickens is not significant (P > 0.05). These results are discussed in light of our current linguistic and archaeological knowledge on the origin of indigenous Malagasy chickens.
Lymnaea truncatula, 4 mm in height, were subjected to infection by a single miracidium of Fasciola gigantica, then raised at 23°C until day 60 of the experiment. Histological study of these snails demonstrated a mean redial burden of 34 parasites at day 60, of which one third were degenerating forms. The mean number of living independent rediae did not exceed 5 for the first and second generations. Conversely, in subsequent generations there were as many as 18 rediae per snail at day 60. The first living redia of the first generation in particular gave rise to daughter rediae. Mature rediae appeared at day 35 and especially concerned the first and second generations at day 60. The authors conclude that development of the first and second redial generations occurs during the same period, and that the forms of the first cohort of the second generation are produced from the first redia of the first generation which originated from the sporocyst.
Renitelo breed is a cattle breed created at Kianjasoa station (Madagascar) by a triple crossing Malagasy Zebu x Limousine x Afrikander. This breed besides many valuable advantages, such as rapid growth and drought power, presents a huge disadvantage which is sensitivity to skin disease, dermatophilosis, previously known as streptotrichosis. This disease caused by Dermatophilus congolensis is one of the major threats for the population of Renitelo cattle. An allele of MHC gene has been shown to be dramatically associated to hypersensitivity to the disease in other cattle breed. To bring further information to tick borne disease clinical survey, mainly dermatophilosis, we wanted to verify if such allele could be found in this breed. Renitelo cattle included in this study were chosen for the presence of dermatophilosis lesions in more or less severe form (N = 17). These animals were blood sampled and a genetic analysis on the MHC gene BoLA-DRB3 was performed, by PCR amplification using BOD 31 & BOD 32 primers. Amplified products were analyzed by RFLP using enzymes. Restriction band profiles were characterized according to previously defined patterns. Three cows out of the 17 cattle analyzed for MHC gene presented the hypersensitive allele FDA. Two out of the three hypersensitive cows were pure breed while one was half breed. All the cows presented dermatophilosis lesions at least during rainy season but one of them particularly suffered from severe lesions covering all its body and died of the illness. This study shows that hypersensitivity allele found in other bovine breeds can be found in Renitelo breed. This result seemed to suggest that this characterization could be utilized in breeding program for this breed.
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