Analysis of candidate genes for fertility and seasonality traits in Bubalus bubalis

Water buffalo is an important livestock resource, which occupies a critical niche in many ecologically disadvantaged agricultural systems, providing milk, meat, and work power. In Italy, the most important production related to buffalo breeding is milk, traditionally processed into mozzarella cheese. Reproductive efficiency is the main factor affecting productivity in female buffalo, but is greatly penalized by late achievement of puberty, seasonality of calving, long postpartum anoestrus and subsequent calving interval. Buffaloes living under Mediterranean latitudes can be considered to have a tendency to be seasonal breeding animals and their reproductive efficiency is usually negatively affected by increasing day-length. The main environmental factor affecting the regulation of reproductive seasonality is photoperiod, which regulates changes in the daily melatonin secretion by the pineal gland. The melatonin effect is carried out at hypothalamic level, by regulating of GnRH secretion. Aim of this work has been the polymorphism analysis of different candidate genes for fertility and seasonality traits (STAT5A, SERPINA14 and TNFA for fertility and MTNR1A for seasonality) in buffalo species. Two sets made up of 12 samples were used for SNP discovery analysis, one for fertility traits, containing animals belonging to the tails of distribution for calving interval, and the other for seasonality, composed by 6 animals with calving occurred from August to September and 6 with calving from March to May. Seven single nucleotide polymorphisms were found, of which a C>T substitution in MTNR1A gene, already found in literature and associated to seasonality in different species, and 6 novel SNPs, of which 2 in exon 4 of TNFA gene and 4 in STAT5A gene (1 in exon 8 and 3 in introns). The results of SNP genotyping analysis on a preliminary sample of 100 buffaloes are presented.