The effect of different levels of dietary fat on the growth of rainbow trout (Salmo gairdneri Richardson)

Two types of fat, represented by cod liver oil and lard, were added at various levels to the diet of rainbow trout. The food intake of the trout and their growth rate were measured. The results indicated that when cod liver oil was used as the fat supplement, the amount and the water temperature affected food intake and weight gain; fish fed on lard showed only a slight loss of appetite.     

Differential responses of rat trophoblast cells and embryonic fibroblasts to cytokines that regulate proliferation and class I MHC antigen expression

TNF-alpha and type I IFN (IFN-alpha/beta) are present in the uteroplacental unit during the course of normal gestation. IFN-gamma is likely to be present during infections. To identify potential effects on two types of blastocyst-derived cells, TNF-alpha, IFN-alpha/beta, and IFN-gamma were tested for the ability to modulate proliferation and the expression of class I MHC Ag by rat trophoblast cells and embryonic fibroblasts. The three cytokines had opposite influences on cellular proliferation by the two types of cells. Growth of the trophoblast cells was inhibited by TNF-alpha, IFN-alpha/beta, and IFN-gamma, whereas both TNF-alpha and IFN-alpha/beta enhanced fibroblast proliferation. The two endogenous cytokines had different effects on class I Ag expression by trophoblast cells and fibroblasts: TNF-alpha failed to induce trophoblast cell class I Ag and IFN-alpha/beta was a poor inducer whereas fibroblast Ag were induced by both cytokines. Moreover, combinations of TNF-alpha and IFN did not increase trophoblast cell class I Ag whereas the same combinations synergized to induce class I Ag expression by fibroblasts. In contrast, IFN-gamma was a highly efficient inducer on both types of cells. The results suggest that 1) cytokines in the uteroplacental unit may orchestrate some of the events associated with placental and embryonic development by exerting differential effects on two embryologically distinct types of cells and that 2) infections may disrupt normal events.