Lipoproteins are essential for the export of the products of dietary lipid from enterocytes into the circulation. Expression and function of apolipoproteins in the zebrafish is similar to that observed in mammals; at least one paralog from each of the ApoA-I, ApoB, ApoE, and ApoA-IV families is expressed in the larval zebrafish intestine (13). There is evidence that division of apolipoprotein function among organs is regulated by different mechanisms that achieve the same end in zebrafish and mammals: while different variants of ApoB are produced in the mammalian intestine and liver via RNA editing, larval zebrafish produce mRNA for the ApoB paralog b.1 in the intestine and liver and ApoBb.2 in the liver only. Similar compartmentalization of paralog expression between the liver and intestine is observed in the other apolipoprotein families as well (13) (Figure 3). Intestinal lipid accumulation in animals treated with an MTP inhibitor shows that as in the larval zebrafish yolk, availability of functional ApoB in necessary for normal rates of lipid export from the intestine, and that enterocyte lipid droplets are the destination of excess dietary fatty acids when export is slowed (73–75). The MTP inhibitor lomitapide is effective in larval zebrafish (72). It has also been observed that in mammals as the dietary fat content increases, chylomicron number reaches a plateau but average chylomicron size continues to increase, suggesting that apolipoprotein expression is the limiting factor in the rate of lipid export from the intestine (76).