Effect of diet and MC4R genotype on nutrient digestibility and nitrogen balance in Kacang goats

This study aims to determine the effect of the relationship between feed treatment and Melanocortin 4 receptor (MC4R) genotypes on nutrient digestibility and nitrogen balance in Kacang goats. Blood samples were collected from 20 Kacang goats, and genomic DNA was extracted by using a Geneaid isolation kit. Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) was used to genotype blood samples at the SNP position g.1079C/T cut by the KpnI enzyme. A 2 × 3 factorial design with two diet factors (diets 1 and 2) and three genotypes (homozygotes CC and TT and heterozygote CT) was used. The diet 1 and 2 groups comprised 4 goats with the TT genotype, 4 goats with the CT genotype and 2 goats with the CC genotype. Diet 1 contained an additional 400 g of concentrate with 11.25% crude protein (CP) and 55.88% total digestible nutrient (TDN) and
diet 2 contained a total mixed ration containing 12.46% CP and 67.92% TDN. Results demonstrated that diet and
MC4R genotype had a nonsignificant interactive effect (P>0.05) on nutrient digestibility, N balance and blood
composition. However, feed factor shown a significant result (P<0.05) on EEI, NDFI, DM, CP, EE, NDF, DM, CP, EE and NDF on TT genotype (P0) with the highest level than CC and CT genotype (P1). The P0 goat group absorbs a lot of nitrogen in the body, however the P1 goat group is able to utilize the nutrient efficiently in the body. Kacang goats with the TT genotype can be selected as livestock that excel in utilizing nutrients in feed.