Blood group and biochemical polymorphism in the Malabari breed of goat and its exotic crosses

Abstract

Realising the importance of blood groups and biochemical polymorphism in livestock improvement a study was undertaken in 305 adult goats of Malabari breed and its exotic crosses viz. Saanen x Malabari and Alpine x Malabari, to identify the blood group factors and polymorphism, if any, at haemoglobin, potassium and erythrocyte glutathione (GSH) loci and their utility as genetic markers for selection. Standard haemolytic test and absorption technique were performed to produce monovalent reagents and to type the goats. The different haemoglobin types were detected employing horizontal starch gel electrophoresis. The potassium concentration in whole blood and the GSH concentration in erythrocytes were estimated by Flamephotometry and Spectrophotmetry respectively. Twelve blood group reagents M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11 and M12 were produced during the present study from the nineteen polyvalent goat sera obtained from Switzerland. The phenotypic frequencies of different blood group factors were different from each other among the three genetic groups. The blood group factors M4, M10 and M12 were not observed in the Malabari goats. In electrophoretic separation, 94 per cent of the goats showed only one haemoglobin band (HbAA) and six per cent showed two bands (HbAB). HbBB was not observed in any of the genetic groups. Inheritance pattern of Hb alleles revealed that they inherit as autosomal co-dominant alleles. The frequency of HbA allele was 0.98 in Malabari and Saanen x Malabari and 0.97 in Alpine x Malabari, the difference being non significant. It was observed that the goat populations were in Hardy-Weinberg equilibrium with respect to the haemoglobin locus. The genetic group had no effect on the concentration of whole blood potassium. The frequency distribution of potassium concentration in the pooled population showed a distinct bimodality, on the basis of which the goats were classified into two distinct types viz. LK ( < 22 meq/1) and HK ( > 22 meq/1). 76.39 per cent of the pooled population were the LK type, a situation not reported in Indian goats. The potassium phenotypes are controlled by two autosomal alleles, KL (determining LK) and KH (determining HK), the KL being dominant over KH. The gene frequencies of KL and KH were 0.53 and 0.47 in Malabari, 0.50 and 0.50 in Saanen x Malabari and 0.52 and 0.48 in Alpine x Malabari, the difference among the three genetic groups being non significant. The genetic groups had significant effect on the potassium concentration in LK type goats, but such effect was not noticed in HK type goats. The genetic groups had significant effect on the erythrocyte glutathione (GSH) concentration. The frequency distribution of GSH concentration in the pooled population revealed a bimodality. Goats with GSH concentration of > 60 mg/100 ml RBC were classified as GSH-high type and those with < 60 mg/100 ml RBC were classified as GSH-low type. The frequency percentage of GSH-high type in the pooled population was 85.26. Among the three genetic groups, Alpine x Malabari had the highest frequency of 88.48 per cent and Malabari had the lowest frequency of 76.56 per cent. Inheritance pattern of GSH phenotypes showed that in goats GSH types are controlled by two autosomal alleles GSHH (determining GSH-high type) and GSHh (determining GSH-low type), the GSHH being dominant over GSHh. The frequencies of GSHH and GSHh were 0.51 and 0.49 in Malabari, 0.62 and 0.38 in Saanen x Malabari and 0.66 and 0.34 in Alpine x Malabari, without any significant differences among the genetic groups. The frequencies of potassium and GSH alleles and also their concentration did not change over the two generation in any of the genetic groups except in Saanen x Malabari, wherein the mean GSH concentration GSH-high type goats of third generation was significantly higher than that of the second generation. Sex did not influence the concentration of potassium and GSH. A valid conclusion could not be drawn on the effect of sire on the potassium and GSH concentration in its offspring. Studies revealed that haemoglobin, potassium and GSH were not genetically associated. Haemoglobin type had no effect on packed cell volume and concentration of potassium and GSH. The LK type goats had significantly higher packed cell volume in all the genetic groups. The potassium type had no effect on the concentration of GSH in the crossbred goats but in Malabari the HK types had significantly higher concentration in GSH than that of LK types. Goats with HbAA phenotype had heavier body weight at different ages when compared to that of HbAB type. However, the differences was significantly only for the weight at one year in Malabari and weight at nine months in crossbreds. Haemoglobin type had no effect on the production traits. In general, the growth and production traits were not seen influenced by the potassium and GSH types.