Kantian Ethics
Kantian Ethics was created by Immanuel Kant, it is a way of thinking that has two kinds of imperatives, hypothetical and categorical.
Kant did not believe in animal testing as he believed that soon it would lead to human testing and this was not alright.
Also, he did not believe you could use people or animals as a means to an end. He famously said, "“If any acts of animals are analogous to human acts and spring from the same principles, we have duties towards the animals because thus we cultivate the corresponding duties towards human beings.”
Although our duties to animals are indirect it is still important that they are treated in humane ways as animals are here to serve man so they will affect humans.