How would you analyze Shylock's statement, "If it will feed nothing else it will feed my revenge," as stated in The Merchant Of Venice?

These words are spoken by Shylock in reply to a question by Salarino at the beginning of Act 3. Salarino and Salanio, associates—but not friends—of Antonio had been discussing a rumor that Antonio had lost a ship laden with precious cargo when they encounter Shylock. Shylock had lent Bassanio, Antonio's closest friend, three thousand ducats and Antonio had signed a bond as a guarantee that the amount would be repaid within three months. If Antonio should forfeit, Shylock could cut out a pound of his flesh as compensation. 

When Salarino tells Shylock about Antonio's unfortunate mishap, the Jew insists that Antonio had made a promise and that he should see to it that the bond is settled. Salarino then asks Shylock,

Why, I am sure, if he forfeit, thou wilt not take
his flesh: what's that good for?

This is a logical and common-sense inquiry, since there is nothing that Shylock can really do with a pound of human flesh. Shylock, however, replies,

To bait fish withal: if it will feed nothing else,
it will feed my revenge.

Shylock states that, although human flesh is unusable on its own, he will still use it as fish bait. If it should be useless to feed fish or for any other purpose, Shylock would use the flesh to satisfy his need for revenge. Shylock clearly states his malicious intent in this regard: he seeks vengeance and would harm Antonio to get satisfaction. If Shylock could cut out Antonio's flesh, Shylock would be satisfied. Shylock then goes on to state why he despises Antonio so much:

He hath disgraced me, and
hindered me half a million; laughed at my losses,
mocked at my gains, scorned my nation, thwarted my
bargains, cooled my friends, heated mine
enemies; and what's his reason? I am a Jew. Hath
not a Jew eyes? hath not a Jew hands, organs,
dimensions, senses, affections, passions? fed with
the same food, hurt with the same weapons, subject
to the same diseases, healed by the same means,
warmed and cooled by the same winter and summer, as
a Christian is? If you prick us, do we not bleed?
if you tickle us, do we not laugh? if you poison
us, do we not die? and if you wrong us, shall we not
revenge? If we are like you in the rest, we will
resemble you in that. If a Jew wrong a Christian,
what is his humility? Revenge. If a Christian
wrong a Jew, what should his sufferance be by
Christian example? Why, revenge. The villany you
teach me, I will execute, and it shall go hard but I
will better the instruction.

In his speech, Shylock says he has been a victim of Antonio's prejudice for the simple reason that he is a Jew. Antonio had no reason to treat him so unfairly. Shylock is clearly bitter about such ill-treatment. He compares the attributes Jews and Christians have, stating that their human experience is alike in every way. Jews are just as human as Christians.

In addition, Shylock argues it is equally normal for both Christians and Jews to seek revenge for wrongs being done to them. Both would seek some kind of recompense and satisfaction from the one who wronged them. The implication is that there is nothing wrong in what he now seeks, for a Christian would have done the same. Furthermore, Shylock states he had been taught to be wicked by Christians through their unjustified malice toward him; he is just returning the favor.  

The Jew is relentless in his pursuit of vengeance and he later brings Antonio before the court, seeking recompense. Shylock stubbornly refuses to consider any alternatives and appeals for him to be merciful. In the end, he is tripped up by his own malice and loses everything he owns, including his religion.