Should I perform a multiple univariate analysis or a multivariate analysis?

Hi all!

I looked at different examples online and I think that my problem can be solved by performing a multiple univariate test, but I want to make sure that I am not losing any information.

I have 15 rats assigned to 3 food groups. Their body weight, heart weight, liver weight, kidney weight, spleen weight and ceruloplasmin are measured. I want to know if the food group influences each measurements.

Q3 = xlsread('Q3.xls');
Diet = categorical(Q3(:, 2));
BW = Q3(:, 3);
HW = Q3(:, 4);
LW = Q3(:, 5);
KW = Q3(:, 6);
SW = Q3(:, 7);
CERUL = Q3(:, 8);

[p,tbl,stats] = anova1(BW, Diet);
figure();
cBW = multcompare(stats', 'Alpha',0.05)

[p,tbl,stats] = anova1(HW, Diet);

[p,tbl,stats] = anova1(LW, Diet);
figure();
cLW = multcompare(stats', 'Alpha',0.05)

[p,tbl,stats] = anova1(KW, Diet);

[p,tbl,stats] = anova1(SW, Diet);

[p,tbl,stats] = anova1(CERUL, Diet);
figure();
cCERUL = multcompare(stats', 'Alpha',0.05)