BENVENUT, C. L.

CHAVES, S. C.

COUTINHO, R. M. A.

NAVARRO, A. M. do C.

NEVES, M. R. M.

VIEIRA, L. da S.

ZAROS, L. G.

Repository Open Access to Scientific Information from Embrapa

PHENOTYPIC MARKERS TO IDENTIFY RESISTANT AND SUSCEPTIBLE CROSSBREED GOATSTO GASTROINTESTINAL NEMATODES INFECTIONCoutinho, R. M. A.1, Benvenut, C. L.2, Neves, M. R. M.2, Chaves, S. C.2, Navarro, A. M. do C.2, Vieira, Lda S.2, Zaros, L. G.11. UFRN, Universidade Federal do Rio Grande do Norte.   2. Embrapa, Embrapa Caprinos e Ovinos.renacoutinho@yahoo.com.brAbstract / Resumo:Phenotypic markers can be used to determine the response to gastrointestinal nematodes infection. Thepresent study aimed to characterize 60 crossbreed goats (1/2 Anglo-Nubian x 1/2 Saanen) naturally infectedby gastrointestinal nematodes using phenotypic markers (parasitological, hematological and production) toidentify the most resistant and the most susceptible animals from the herd. Until the beginning of theexperimental period the animals were free from worms and kept on pasture (Panicum maximum cv. Tanzania)during 97 days. Each seven days they were weighted, submitted to body conditional score and to Famachamethod to worm control and blood samples were collected to determined eosinophil counts (EOS), the packedcell volume (PCV) and total serum protein levels (TSP) and feces to determine the EPG (eggs per gram)counts and the infective larvae. During this period, when the EPG means was 800 eggs / g (42 days), animalswere wormed and relocated in the same experimental area until the EPG means reached 800 eggs / g again(90 days). At this time, based on the EPG means, the animals were classified as resistant and susceptible andslaughtered to recover the gastrointestinal nematodes for subsequent count and species identification. Theresults were submitted to variance analysis and the correlations among variables were obtained by Pearson'scorrelation. On feces cultures, Haemonchus sp. (67%) was the predominant genus, followed byTrichostrongylus sp. (32.6%) and Oesophagostumun sp. (0,4%). The EPG means of susceptible group washigher than resistant group. (4.8 fold) (3653.5 eggs / g and 758.5 eggs / g; P <0.0001). This one presentedhigher PCV means (26.4%) and TSP levels (6.32 g / dl) than susceptible animals (24.0% and 6.0 g / dl,respectively; P <0.0001). Differences were observed regarding to Famacha degree (1.8 and 2.2; P <0.0001),body score conditional (2.7 and 2.5; P <0.001) and weight (22.9 kg and 19.7 kg; P <0.001) between resistantand susceptible groups, respectively. The correlation between OPG x VG, VG x Famacha degree, OPG xweight were negatives (r = -0.57, r = -0.35, r = -0.22; P <0.0001), and between VG x PPT and Famachadegree x OPG were positives (r = 0.53, r = 0.28; P <0.001). It can be inferred that was possible to identifyresistant and susceptible goats using phonotypical markers, verifying a better performance of resistant animalswhen infected by gastrointestinal nematodes.

Phenotypic markers to identify resistant and susceptible crossbreed goats to gastrointestinal nematodes infection.

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