Buffalo milk transcriptome: A comparative analysis of early, mid and late lactation.

The expression of genes and their regulation during lactation in buffaloes remains less understood. To understand the interplay of various genes and pathways, the milk transcriptome from three lactation stages of Murrah buffalo was analyzed by RNA sequencing. The filtered reads were mapped to the Bubalus bubalis as well as Bos taurus reference assemblies. The average mapping rate to water buffalo and Btau 4.6 reference sequence, was 75.5% and 75.7% respectively. Highly expressed genes (RPKM > 3000), throughout lactation included CSN2, CSN1S1, CSN3, LALBA, SPP1 and TPT1. A total of 12833 transcripts were common across all the stages, while 271, 205 and 418 were unique to early, mid and late lactation respectively. Majority of the genes throughout lactation were linked to biological functions like protein metabolism, transport and immune response. A discernible shift from metabolism in early stage to metabolism and immune response in mid stage, and an increase in immune response functions in late lactation was observed. The results provide information of candidate genes and pathways involved in the different stages of lactation in buffalo. The study also identified 14 differentially expressed and highly connected genes across the three lactation stages, which can be used as candidates for future research.