We would like to write a custom theme having alternate colors in datatables, any hint outa there?
Well, LoL after a short StackOverflow surf I got the answer by myself
You must write in theme.less your custom rules, for example:
tbody tr.level0:nth-child(even) td { background-color: darken(@theme-color-background-tinyContrast, 10%) !important;}
tbody tr.level1:nth-child(even) td { background-color: darken(@theme-color-background-tinyContrast, 5%) !important;}
tbody tr.level2:nth-child(even) td { background-color: lighten(@theme-color-background-tinyContrast, 5%) !important;}
`